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Review

Technologies and Innovations for Biomass Energy Production

by
Azwifunimunwe Tshikovhi
1,* and
Tshwafo Ellias Motaung
1,2
1
Department of Chemistry, College of Science, Engineering, and Technology, University of South Africa, Johannesburg 1709, South Africa
2
Department of Chemistry, Sefako Makgatho Health Science University, P.O. Box 94, Ga-Rankuwa 0204, South Africa
*
Author to whom correspondence should be addressed.
Sustainability 2023, 15(16), 12121; https://doi.org/10.3390/su151612121
Submission received: 28 May 2023 / Revised: 6 July 2023 / Accepted: 1 August 2023 / Published: 8 August 2023
(This article belongs to the Special Issue Renewable Energy Technologies for Sustainable Development)
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Abstract

:
Biomass is considered one of the prospective alternatives to energy and environmental challenges. The use of biomass as bioenergy has gained global interest due to its environmentally benign, renewable, and abundant characteristics. Numerous conversion technologies have been developed over time to convert biomass into various energy products. This review presents a summary of the different biomass conversion technologies used for bioenergy production. These include thermochemical, biological, physical, biochemical, and hybrid system technologies. It summarizes the production of different bioenergy products such as bio-oil, biodiesel, and fuel via various conversion technologies. The competitive advantages, potential environmental impacts, and challenges of these biomass conversion technologies are discussed. The recycling of biomass can solve a lot of current energy challenges. However, conversion technologies exhibit some challenges relative to upscaling and commercialization due to their immense operational and investment expenses and high energy usage.

1. Introduction

Owing to the exhaustion of fossil resources as well as the ongoing decline of environmental value, the use of renewable resources is essential. Among the numerous renewable resources, biomass is considered a better option for non-renewable fossil resources. It is abundant, cost-effective, and environmentally friendly [1]. The world’s fourth largest source of energy is biomass, and it is competent to manage rural development and energy security [2]. Presently, biomass supplies approximately 8–15% of society’s energy supplies as electricity, heat, and fuels for transportation, and about 40–50% in many developing countries. It is anticipated that nearly 33–50% of primary energy consumption in the world could be met in 2050 via biomass [3,4,5]. There are various kinds of biomass, such as municipal solid waste (textiles, plastics, and paper), agricultural waste (animal farm byproducts, agro-industries, and crops), forestry biomass (wood products activities), energy crops, and algae [6]. It is important to develop technologies that would convert waste biomass into bioenergy and chemical products, bearing in mind the environmental influence and thermodynamic efficacy [7,8]. Based on the circular economy, waste-to-energy conversion technologies seem to be one of the major background subjects of biomass research.
In recent years, several researchers have studied various process types for the conversion of biomass. Different processes, such as thermochemical and biochemical, have been used to convert biomass into valuable forms of energy [9]. The conversion technology option is dependent on the amount of property, the type of biomass feedstock, the nature of the energy anticipated, i.e., endues requirements, commercial settings, environmental values, and project-specific aspects. Biomass could be converted into three major products, which include chemical feedstock, transportation fuels, and power/heat generation [10,11]. Thermochemical and chemical processes are typically reported by different researchers. There are not many reports on the use of physical processes and the hybrid system. Physically converted biofuels have been widely used in rural areas for domestic purposes (cooking and heating), and hybrid systems are still under research. Therefore, in this review, we present a summary of different biomass conversion technologies used for bioenergy production, including thermochemical, biological, physical, biochemical, and hybrid/combined systems technologies (Figure 1, Table 1). It summarizes the production of different bioenergies such as biodiesel, fuel, bio-oil, and other chemical products from biomass feedstocks and how these processes are carried out. The potential environmental impacts, benefits/advantages, and challenges of these biomass conversion technologies will be discussed. Their economic sustainability and the potential future of bioenergy derived from biomass feedstocks will also be highlighted.

2. Biomass Conversion Technologies

2.1. Thermochemical Conversion

The biomass thermochemical process converts biomass into a higher-quality fuel or H2-rich syngas to chemicals via Fischer-Tropsch (F-T) production [19]. Drying, pyrolysis, heterogeneous char, and homogeneous reforming reactions of pyrolysis materials are the major phases involved in the thermochemical process [20]. This process is commercially more attractive due to its improved flexibility, product selectivity, quicker conversion degree, higher process effectiveness, and different market for byproducts [21].
Thermochemical technology mostly uses process settings that entail costly resources in the process equipment and conditions that use high temperatures and pressure [22]. The challenge with thermochemical is that it is expensive to obtain and install the infrastructure as compared to the feedstock’s low cost. Therefore, to enable cost-effectiveness, more research and development associated with the industry is desirable [23].
Most current biomass thermochemical conversion processes use comprise pyrolysis, hydrothermal liquefaction, gasification, combustion, torrefaction, and incineration (Table 2).

2.1.1. Pyrolysis

The pyrolysis technique is a biomass thermal breakdown process at 500–1000 K temperatures in the absence of oxygen, resulting in a solid residue, liquid, and gas (Figure 2). The solid residue well known as biochar or charcoal, which is a carbonaceous composite with a porous form [37]. A highly heterogeneous product mixture is formed during the pyrolysis process. This product mixture contains a liquid phase, a solid phase/char, and gaseous material, which are carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), and hydrogen (H2). Pyrolysis oils entail solid particles, aromatic compounds, oxygenated aliphatic, high water content ranging from 15–30 wt%, several oxygenates, and nitrogen compounds. So, further processing is needed before it can be used as a transportation fuel [38]. The pyrolysis process is influenced by various factors like catalysts, temperature, and retention time [39].
The pyrolysis process can be separated into three subsets depending on the operational settings, i.e., fast, flash, and slow/conventional pyrolysis [40,41].
Fast Pyrolysis involves the thermochemical breakdown of biomass materials in the absence of air, producing liquid (bio-oil), a combustible gas mixture (syngas), and biochar (Figure 3) [42]. This process comprises lignocellulosic feedstock thermal disintegration at about 773 K via a high quenching and heating degree with a fluidized bed reactor. As for the bio-oil product to be successfully produced, it takes around 0.5–3 s of residence time and 400–600 °C thermal treatment, which might be improved for hydrocarbon liquid fuels [43]. Of the three types of pyrolysis, fast pyrolysis has the highest bio-oil yield of 50–75%, while roughly 10–20% is converted into char [44,45]. Quick cooling of pyrolysis vapor, controlled reaction temperatures, and extremely high heating and heat transfer rates are the main characteristics of a fast pyrolysis process [46].
Fast pyrolysis is a simple process. However, the bio-oil produced may complicate the properties obtained from the original feedstock characteristics. This makes it a substandard fuel alternative [47]. Fast pyrolysis is a well-developed technological process. However, upgrading technologies for this process is still in the beginning phases of the demonstration. Therefore, it will probably take some time before it is widely used on a commercial basis [48].
Flash pyrolysis is considered an enhanced and adapted method of fast pyrolysis. The flash pyrolysis method entails elevated reaction temperatures (400–800 °C), a high heating rate (1000–100,000 °C/s), a small biomass particle size, and a relatively quick gas residence time of about 0.5 s [49]. In flash pyrolysis, the biomass-to-oil conversion efficiency can reach up to 70%. But the quality and stability of the produced oil are a big challenge due to the formation of pyrolysis water [50]. The major problem of using flash pyrolysis on an industrial scale is positioning a reactor whereby the input biomass could occupy for a brief time at exceedingly elevated heating degrees [51].
Slow pyrolysis comprises an extended duration of biomass and typically produces gas and char [47]. As a result, there are fewer liquid and gaseous products, but char production increases [52,53]. Slow pyrolysis is carried out at a heating rate of roughly ∼10 °C/min for average temperatures between 350 and 750 °C for about an hour of residence time [54,55]. This process produces approximately 35% biochar, 30% condensable substances, and 35% syngas by mass product yield [56]. Based on process factors such as vapor residence time, heating rate, and temperature, biofuel products differ in composition [57]. Additional coke, tar, and heat-stabilized products are produced when a longer residence time results in the secondary conversion of primary products. Thus, slow pyrolysis is sometimes known as carbonization [58]. Slow pyrolysis creates biochar with significant environmental advantages and fewer CO2 emissions. However, the disadvantages of this process are limited scalability, high cost, and stable feedstock quality [59,60].

2.1.2. Hydrothermal Liquefaction (HTL)

Hydrothermal liquefaction technology converts biomass into hydrothermal biochar in a sealed system with water as the medium under particular in-house pressures and temperatures. This process is effective in converting biomass into biomass with a higher energy density [61]. The HTL process is regulated by a difficult series of reactions and alterations in subcritical water. The mechanism of this process comprises (1) the biopolymers’ hydrolysis into water-resolvable peptides and (2) the fragmentation of intramolecular and intermolecular hydrogen linkages into simpler monomers, namely glucose, and additional compounds (furfural compounds, acetic acid, and acetaldehyde) [62].
HTL has various advantages as compared to other thermochemical techniques; it does not need preceding thermal drying, thus resulting in cost-effective wet materials. It utilizes pressurized water as a reactant and reaction medium, and it is versatile and environmentally benign [63].
Also, the bio-oil attained from the HTL method is of higher quality and yield, with lower water and oxygen content. Nonetheless, this process utilizes high pressure, which might result in the equipment required for industrial-scale procedures being expensive [64].

2.1.3. Gasification

Biomass gasification is typically an indirect combustion method of municipal plastic waste (MPW) to synthetic gases or fuel by waste half oxidation in the presence of oxidants [65]. This process involves the alteration of a solid/liquid organic mixture in a solid phase and a gas/vapor phase. The gas phase, also known as syngas, has a great heating capacity and could be used for biofuel or the generation of power (Figure 4) [66].
The product gas mixture of the gasification process comprises nitrogen (N2), carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and hydrogen (H2) [68]. The main familiar gasification factors are oxygen, carbon dioxide, steam, and air, where steam and air are commonly used. However, they possess distinct advantages and limitations [69,70].
In gasification technology, the use of dry biomass is much more effective compared to wet biomass because no further drying is required [71]. The gasification process comprises drying, pyrolysis, combustion, char gasification, and cracking stages (Figure 5) [72].
Biomass gasification could be considered high-temperature gasification (HTG) or low-temperature gasification (LTG), depending on the temperature. In the LTG method, gas and hydrogen can be acquired from biomass of low calorific value. The LGT process has great advantages such as easiness, operation protocol efficiency, and evasion of ash-related complications. [73]. There are various gasification technologies available, which include fluidized bed gasifiers, fixed bed gasifiers, and entrained flow gasifiers. Lately, there have been reports on new gasification technologies to decrease tar quantity, increase hydrogen quantity in the producer gas, and increase biomass gasification energy proficiency [74].
Biomass gasification is a supple technology; it might be employed for the production of electricity, or on the other hand, as a feedstock for chemical methods. Nevertheless, it has shortcomings that limit its flexibility and efficiency. For an installation to successfully operate, a steady and adequate biomass supply and type of biomass should be certain [71].

2.1.4. Combustion

Biomass combustion technology is known to be the ancient and most commonly applied thermochemical conversion process [75].
The combustion method is well known to be the only method to produce electric and heat power. There are three major steps involved during the combustion of biomass: drying, pyrolysis, and reduction; unstable gases; solid char combustion. More than 70% of the total heat generation is contributed by the combustion of unstable gases [76]. Though the combustion process can be used for any form of biomass, it can only be achieved if the moisture volume in the biomass is below 50% [51].
Biomass combustion has great proficiency in the production of heat. As a result, making it economically viable. But the complicated combustion method consists of continuous solid-gas and solid-solid reactions [19]. The combustion process requires air, heat, and fuel. If one of these three requirements is detached, burning ends. However, when all three are present in precise ratios, combustion is self-sufficient due to the extra heat released from the fuel, which initiates more burning [77].

2.1.5. Torrefaction

Torrefaction, well known as high-temperature drying or roasting, is a thermal treatment method whereby biomass is heated in a 200–300 °C temperature range for a short duration in an inert condition. The torrefaction process, or mild pyrolysis, produces solid char by first heating, pre-drying, post-drying, intermediate heating, torrefaction, and solid cooling of biomass materials [78]. Because torrefaction operates at a lower temperature and for a shorter period of time, it is more appropriate to improve the quality of the solid char [21]. During the torrefaction process, the properties of biomass are reformed into finer fuel characteristics for applications in gasification and combustion [33,34]. Torrefaction on a lab scale is mostly conducted by the use of thermogravimetric analysis (TGA), a small-scale tube reactor, and an oven [79]. Torrefied biomass has great benefits, which include hydrophobic character, closely correlated properties like coal, grindability, and ease of crushing. The products obtained from this process include lactic acid, condensable gases like water vapor, furfural, phenol, methanol, acetic acid, formic acid, and more oxygenates (Figure 6). Non-condensable gases also acquired from this method are carbon dioxide, carbon monoxide, and a small amount of hydrogen and methane [80]. The combustion heat of the non-condensable waste gases released during this process increases with an increase in torrefaction temperature [33]. Regardless of the great benefits of using torrefaction technology, the economic and technical problems need to be resolved for it to be fully commercialized. Moreover, this process is not scientifically elucidated, and further investigation on the impact of the reaction conditions is necessary [81].

2.1.6. Incineration

Incineration is the oxidative combustion process under aerobic conditions at high temperatures (900–1100 °C) with the aim of energy recovery and a decrease in volume. The final products from the incineration process are ash, solids, and combustion gas, which could be applied as heat supplies [8]. The most important steps in the incineration technique are evaporation and degassing, pyrolysis, and gasification [82]. However, the use of incineration generates a lot of chemicals, harmful gases, and greenhouse gas (GHG) emissions, resulting in water and air pollution. Thus, the incineration facility institution in every area will entail effective emission-cleaning innovation together with local community approval [22].

2.2. Biological

Microbial systems such as Escherichia coli and Saccharomyces cerevisiae are generally used in biological methods. These are enhanced for a specific chemical product by constructing a set of reactions in a metabolic pathway. In this process, there are a few advantages of using biological catalysts, such as the diverse carbohydrate feedstocks’ lenience, numerous reactions with no intermediate separations, variety of chemical products, and vastly selective reaction networks [83].
Biological conversion processes are considered environmentally friendly. But their fermentation period, use of costly hydrolytic enzymes, and the sensitivity of microorganisms to various aspects like growth settings, impurities, sugar substrates, nutrients, and inhibitors render them time-consuming [21]. Some of the biological methods include fermentation, anaerobic digestion, and aerobic composting (Table 3).

2.2.1. Fermentation

The fermentation method transforms biomass into desirable bio-products such as bioethanol, bio-hydrogen, and biogas in the presence of microorganisms (i.e., bacteria, fungi, and yeast) [89]. Biomass fermentation comes with great challenges. This is attributed to the obligation to convert many hexose sugars and pentose to ethanol in a simultaneous saccharification co-fermentation (SSCF) step. Pichia and Saccharomyces yeast species, along with Klebsiella, Zymomonas, and Escherichia coli bacteria, have been natively arranged to ferment arabinose sugars, glucose, and xylose [90].
The fermentation method is known to have the following benefits:
  • Regardless of the quality of the biomass, the whole biomass could be used, together with lignin.
  • Costly enzyme removal and challenging pretreatment steps.
  • Higher biocatalyst selectivity.
  • The H2:CO proportion for bioconversion independence
  • Aseptic process of the fermentation of syngas due to the production of syngas at elevated temperatures
  • Bioreactor operation under normal conditions.
  • There are no noble issues with metal poisoning [91].

2.2.2. Anaerobic Digestion

Anaerobic Digestion (AD) is a sequence of interrelated biological reactions whereby organic material is converted into methane (CH4), carbon dioxide (CO2), and anaerobic biomass in the absence of oxygen (Figure 7) [92]. The CH4 yield per unit area is mostly applied to govern the energy efficiency of a given feedstock. It considerably differs across organisms, with growth, geographical setting, and inputs (i.e., water, manure) among identical species [93].
Anaerobic digestion occurs in three stages:
  • The complex organic macromolecules are hydrolyzed into simpler, solvable molecules.
  • Acid-forming microbes convert molecules into basic organic acids, hydrogen, and carbon dioxide. The main acids produced include ethanol, butyric acid, propionic acid, and acetic acid.
  • Formation of methane by the methanogenic microbe. This is formed by disintegrating acids into methane and carbon dioxide or by reducing carbon dioxide reduction with hydrogen [94,95].
Different factors, such as the population of microbes employed during the procedure and its source, pH, temperature, redox potential, and harmful elements existence (cyanide, unstable fatty acids, heavy metals, and ammonium) in the digester, together with the carbon to nitrogen volume proportion of the feedstock, affect the efficiency of the AD process [96].
The AD method is highly recommended for encouraging renewable energy as compared to other technology processes because it does not require oxygen, has lesser nutrient requirements, generates energy carriers via harmless methods, and allows residual biomass reuse in agriculture [97,98]. Nevertheless, it has shown some disadvantages, such as difficulties in storing biogas and the fact that the quality of the biogas produced is mostly substandard and contains hydrogen sulfide (H2S), which is expensive to remove [99].
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Figure 7. Overview of the anaerobic digestion process [100]. Reprinted with permission from Ref. [100]. Copyright 2006 Taylor & Francis.
Figure 7. Overview of the anaerobic digestion process [100]. Reprinted with permission from Ref. [100]. Copyright 2006 Taylor & Francis.
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2.2.3. Aerobic Composting

In aerobic composting/degradation, microorganisms use oxygen from the air to disintegrate biomass into heat, CO2, and a solid product [75]. It alters organic waste biomass into steady humus using microorganisms in specific external environments and is often used in the treatment of biomass waste [101,102]. Compounds of carbon and nitrogen are easily converted and used as energy and protein sources by the microbes during the composting procedure, producing heat, CO2, H2O, NH3, organic acids, and fully developed compost products at the final phase [103]. Aerobic composting has many benefits, notably reducing animal manure quantity, destroying pathogens, and turning manure waste into nutritious, steady organic matter (e.g., compost) that could enhance the fertility of soil. However, the excess release of various greenhouse gases (GHGs) such as N2O, CH4, and CO2 from composting procedures reduces the agronomic value and contributes to additional environmental pollution [88].

2.3. Biochemical

Biochemical conversion technologies such as hydrolysis, transesterification, and supercritical water gasification are a blend of biological and chemical pathways (Table 4). This process uses microbes and biological catalysts to convert biomass into gas (CO2/CH4), waste (compost or manure), and H2O [104]. It provides great selectivity in transforming biomass into the final ideal products [105].

2.3.1. Hydrolysis

Hydrolysis is a technique that involves the breakdown of β-1,4 glycosidic cellulose linkages into simple sugars, which are thereafter hydrolyzed to ethanol [109]. Biomass hydrolysis technologies, including acid and enzymatic hydrolysis, are applied to break down feedstock into simple sugars [110,111].
Enzymatic hydrolysis employs enzymes to disintegrate the lignocellulose carbohydrate polymer’s complicated chemical composition [112]. The enzymes denote a green approach to reducing waste production and energy consumption. A green method is a necessity for the setup of cheap and sustainable biorefineries [113]. Enzymatic hydrolysis solely depends on the accessibility and potency of enzymes, which are completely connected to the structural features of biomass [114].
Lignocellulosic biomass enzymatic hydrolysis is one of the significant stages in the production of sugar, leading to the transformation of sugars into biofuels and chemicals [115,116]. Several aspects, including lignin dosage, lignin dispersion and structure, polymerization rate, fiber sizes, accessible surface area and pore size, crystallinity, and others, have a substantial effect on enzymatic hydrolysis [117]. The benefits of the enzymatic hydrolysis method encompass low utility usage, minor corrosion problems, minimal toxicity of hydrolysis products, and higher sugar recovery with smaller inhibitor production. However, there is a cost of cellulases for the bioethanol production of cellulosic materials [118,119].
Acid-based hydrolytic methods have been applied to many feedstocks, namely soft and hardwoods and agricultural residues, in the existence of acid catalysts like sulfuric acid (H2SO4), hydrochloric acid (HCl), and nitric acid (HNO3) [43,120]. Acid hydrolysis is carried out in three steps:
(1)
The acid proton interacts with the glycosidic oxygen, binding two sugar molecules, resulting in a conjugated acid.
(2)
The cleavage C-O linkage and the conjugate acid breakdown to cyclic carbonium ions.
(3)
After the addition of water, there is a release of free sugar and a proton [121].
This process has the advantages of operating at a milder temperature and pressure, having greater sugar retrieval efficacy that might exceed 90% of theoretical output for both glucose and xylose, and having a low cost of ethanol production. But it has greater toxic effects and corrosivity, and reactors that are resistant to corrosion are essential [122].

2.3.2. Transesterification

Transesterification involves a number of successive reversible reactions whereby lipids/triglycerides react with alcohol, mostly methanol, to yield monoglycerides, diglycerides, glycerol, and moieties of fatty acid methyl ester (FAME) biodiesel at each step [89,123,124]. The transesterification efficiency process is affected by factors such as alcohol-to-oil molar fraction, temperature, stirring speed, moisture, microalgal cell wall, reaction period, and the kind of catalyst [123].
This process may be accelerated by different catalysts, which are acidic or alkaline (homogeneous or heterogeneous), enzymes, ionic liquids, and carbon-based catalysts. Homogeneous alkaline catalysis is the most used process for the production of biodiesel. This is attributed to the fact that it accelerates the reaction at low temperatures and atmospheric pressure and can rapidly achieve a significant conversion yield. Potassium hydroxide (KOH) and sodium hydroxide (NaOH) are the most commonly utilized alkaline catalysts for this method [125].
The challenge with the use of these alkaline catalysts is that they can cause the formation of soap-free fatty acids in oils, which is not suitable for microalgal biodiesel production due to the significant concentration of free fatty acids found in microalgal oils. To solve this challenge, acid catalysts are usually used once the concentration of free fatty acids exceeds 1%. Currently, the commercial methods applied depend on triglyceride transesterification with homogeneous alkaline and methanol [126].

2.3.3. Supercritical Water Gasification

The world’s most available biomass is mainly wet, with a moisture level of more than 70%. The probable solution for the energy valorization of wet biomass is using the supercritical water gasification (SCWG) method [127]. Water, the most common element on the surface of the planet, occurs in three states: solid, liquid, and gas. In the hydrothermal vents on the deep sea floor called supercritical water (SCW), water also occurs in a supercritical state (p > 22.064 MPa, T > 373.946 °C) [128]. Biomass treatment in supercritical water might convert it into fuel gases that are enriched with hydrogen [129]. SCW has a unique capacity to break down materials that are typically not soluble in ambient liquid water or steam and has full compatibility with liquid/vapor products from the procedures. This creates a one-step environment for reactions that might require a multi-phase arrangement under normal circumstances. This leads to inter-phase mass transit routes, which might delay reaction rates [76].
The SCWG procedure has great reaction efficacy with the specificity of H2, and the reactions progress rapidly. Furthermore, this method yields high solid conversion (minimal char quantity and tar production) [4]. However, there are disadvantages related to this process, such as the fact that it is essential to operate at high pressure and that corrosion difficulties can happen [108].

2.4. Physical Conversion

Physical or mechanical biomass conversion entails the alteration of biomass via pre-processing operations, reduction/comminution of size, drying, and densification. This process transforms biomass into forms with improved properties such as higher mass density, higher density of energy, and hydrophobicity than raw biomass [130]. Briquetting, extraction, and distillation are the commonly used biomass conversion technologies (Table 5).

2.4.1. Briquetting

Briquetting is a procedure (Figure 8) that converts agricultural and forestry waste into biomass briquettes/bio coal (Figure 9), which are combustible in typical burners. Briquetting is a technology that might provide several socio-economic and environmental benefits, specifically in developing countries where traditional biomass is the main source of energy [131,135,136]. The biomass briquette not only supports the economy of the developing country’s progress but also assists in preserving the environment [137].
Briquettes have various uses in both households and small industrial cottages:
  • Household and heating of water;
  • Heating productive operations, including drying tobacco, fruits, drying tea, and chicken breeding;
  • Heating ceramics and clay products like better cook stoves, pottery, and bricks;
  • Fuel for electricity-generating gasifiers;
  • Operating boilers for steam generation [138,139].
Some of the advantages of briquettes from biomass are that they may be conveyed for prolonged distances with reliable energy storage choices, ensure proper size and density, and are easily affordable [140]. In terms of production, briquettes can be developed using different organic waste constituents. However, the application of the technology itself is costly due to the briquetting press’s elevated pressure, excessive energy usage, and the need for trained personnel [141]. The primary aspect that greatly impacts the briquetting process is the briquette binder. Various briquette binders such as sewage sludge, cow dung, microalgae, molasses, waste paper pulp, starch, and okra stem gum have been tested. The standard and burning efficiency of briquettes are influenced by the binders and the agricultural biomass chosen [142,143].
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Figure 8. Briquetting production method [131].
Figure 8. Briquetting production method [131].
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Figure 9. Example of briquettes made with a manual piston press [144].
Figure 9. Example of briquettes made with a manual piston press [144].
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2.4.2. Extraction

Extraction is a mechanical conversion procedure whereby oil is generated from the seeds of different biomass crops like cotton, groundnuts, and so forth. This procedure not only yields oil but also excess solid/“cake”, which is appropriate for livestock food [145]. It is important to disintegrate the cell walls for complete oil extraction by using different mechanical or non-mechanical methods [107]. The oil recovery process efficiency is influenced by the extraction parameter optimization steps, whereby the optimization is dependent on the oil accumulation in the vegetable fractions, the oil’s physical-chemical properties, and potential applications [133].

2.4.3. Distillation

The distillation process involves the crushing of oilseeds for the extraction of oil. It also consists of steam distillation of the oil mixture and essential oil vaporization. The vaporized oils are then captured and condensed or cooled to get bio-oil [104]. One drawback of the distillation method is the significant energy demand. Distillation needs a lot of energy to heat liquid, change it to vapor, and finally condense the vapor back into liquid at the condenser [146].

3. Hybrid Technologies

Hybrid or combined systems are also under research using blends of different technologies, like thermochemical and biochemical technologies. However, based on the kind and accessibility of the feedstock, every bio-refinery method can yield a particular fuel. Consequently, if these methods could be merged under an integrated waste bio-refinery notion, heterogeneous and several feedstocks may be processed to yield many supplies in the form of fodder, fuel, electricity, heat, and valuable chemicals [22]. Hybrid configuration systems result in the maximum feasible generation efficiency of electricity and minimal hazardous emissions [147].

4. Challenges, Sustainability, and Environmental Benefits

More research is required for the developments in the advanced, affordable methods for production, detoxification, biofuels, and platform chemical analysis [43].
Economic problems may be influenced by technical challenges like poor technology implementation, resulting in high technical risk that could increase operational expenses [148]. Also, the economic aspects significantly rely on the costs related to the collection, transportation, storage, and processing of biomass residues. Therefore, a decrease in the feed value of biomass should be established, which consists of reducing the cost of shipping, enhancing biomass collection systems, and establishing collection systems [149]. Though these biomass technologies are certified environmentally benign, they still have some challenges. Traditional biomass sources like wood result in many environmental consequences, such as the deforestation and degradation of land, the decline of biodiversity, indoor and outdoor contamination, and climate change [150]. To maintain sustainability standards, environmental authorization has become a crucial instrument for enhancing the image of biofuel products on the market [30]. Due to the seasonal nature and annual biomass variability, proper planning is needed to ensure sufficient quality and quantities of the biomass feedstocks. Moreover, biomass pretreatment such as drying and pyrolysis is required to reduce its moisture content and improve energy density, which leads to an increase in cost and production time [12].
Currently, the major challenge of biomass energy is that it is not economically competitive compared to petroleum [151]. To overcome this challenge, the commercialization of biomass products and environmental certification will bring out their economic relevance and create a supply chain that will readily sustain the production of biomass products, as well as improve the image of biofuel products in the market [30,132]. Moreover, biofuel production may be combined with nitrogen-rich municipal wastewater and CO2-rich flue gas treatment to be considered sustainable and economical [152]. Lastly, these biomass conversion technologies are mostly carried out on a small or lab scale. It has been a great challenge to develop a conversion technology that could successfully convert biomass into biofuel on an industrial scale. Currently, researchers are trying to find methods that can improve the existing technologies for large-scale conversions [153].

5. Conclusions

The utility of biomass for the fabrication of various biofuels using biological, thermochemical, physical, biochemical, and hybrid system conversion technologies has been reviewed. It can be concluded that these biomass technologies have great benefits and limitations. Thermochemical technologies are the most commonly used and have proven to be the most efficient in biofuel production. They are deemed commercially feasible. Biological and biochemical technologies exhibit potential that is environmentally benign and economically feasible due to their low energy consumption and greenhouse emission characteristics. Physical conversion technologies are known to be beneficial for different domestic uses, making them a great option in developing countries, particularly in rural areas and regions where traditional biomass is the primary source of energy. More work is still needed on hybrid systems to acquire more information about their benefits and limitations. The recycling of biomass can solve a lot of current energy challenges. However, the conversion technologies employed have shown significant challenges in upscaling and commercialization. This is caused by their operational and investment expenses and high energy usage. More research is required in this area for these conversion technologies to meet certain economic standards and conditions.

Author Contributions

Both authors reviewed the manuscript and contributed equally. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Acknowledgments

The authors acknowledge the Department of Chemistry, College of Science, Engineering, and Technology, University of South Africa for financial support.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Tang, X.; Hu, L.; Sun, Y.; Zhao, G.; Hao, W.; Lin, L. Conversion of biomass-derived ethyl levulinate into γ-valerolactone via hydrogen transfer from supercritical ethanol over a ZrO2 catalyst. RSC Adv. 2013, 3, 10277–10284. [Google Scholar] [CrossRef]
  2. Torres-Ortega, C.E.; Rong, B.G. Intensified Separation Processes for the Recovery and Dehydration of Bioethanol from an Actual Lignocellulosic Fermentation Broth; Elsevier Masson SAS: Paris, France, 2016; Volume 38. [Google Scholar]
  3. Vassilev, S.V.; Baxter, D.; Andersen, L.K.; Vassileva, C.G. An overview of the composition and application of biomass ash. Part 1. Phase-mineral and chemical composition and classification. Fuel 2013, 105, 40–76. [Google Scholar] [CrossRef]
  4. Ding, N.; Azargohar, R.; Dalai, A.K.; Kozinski, J.A. Catalytic gasification of cellulose and pinewood to H2 in supercritical water. Fuel 2014, 118, 416–425. [Google Scholar] [CrossRef]
  5. Vogel, F.; Waldner, M.H.; Rouff, A.A.; Rabe, S. Synthetic natural gas from biomass by catalytic conversion in supercritical water. Green Chem. 2007, 9, 616–661. [Google Scholar] [CrossRef]
  6. Gwak, Y.R.; Kim, Y.B.; Gwak, I.S.; Lee, S.H. Economic evaluation of synthetic ethanol production by using domestic biowastes and coal mixture. Fuel 2018, 213, 115–122. [Google Scholar] [CrossRef]
  7. Nanda, S.; Azargohar, R.; Dalai, A.K.; Kozinski, J.A. An assessment on the sustainability of lignocellulosic biomass for biorefining. Renew. Sustain. Energy Rev. 2015, 50, 925–941. [Google Scholar] [CrossRef]
  8. Duan, Y.; Tarafdar, A.; Kumar, V.; Ganeshan, P.; Rajendran, K.; Giri, B.S.; Gomez-Garcia, R.; Li, H.; Zhang, Z.; Sindhu, R.; et al. Sustainable biorefinery approaches towards circular economy for conversion of biowaste to value added materials and future perspectives. Fuel 2022, 325, 124846. [Google Scholar] [CrossRef]
  9. Behera, B.; Mari Selvam, S.; Balasubramanian, P. Bioresource Technology Hydrothermal processing of microalgal biomass: Circular bio-economy perspectives for addressing food-water-energy nexus. Bioresour. Technol. 2022, 359, 127443. [Google Scholar] [CrossRef]
  10. Saxena, R.C.; Seal, D.; Kumar, S.; Goyal, H.B. Thermo-chemical routes for hydrogen rich gas from biomass: A review. Renew. Sustain. Energy Rev. 2008, 12, 1909–1927. [Google Scholar] [CrossRef]
  11. Jingura, R.M.; Musademba, D.; Kamusoko, R. A review of the state of biomass energy technologies in Zimbabwe. Renew. Sustain. Energy Rev. 2013, 26, 652–659. [Google Scholar] [CrossRef]
  12. Hansen, S.; Mirkouei, A.; Diaz, L.A. A comprehensive state-of-technology review for upgrading bio-oil to renewable or blended hydrocarbon fuels. Renew. Sustain. Energy Rev. 2020, 118, 109548. [Google Scholar] [CrossRef]
  13. Siwal, S.S.; Sheoran, K.; Saini, A.K.; Vo, D.V.N.; Wang, Q.; Thakur, V.K. Advanced thermochemical conversion technologies used for energy generation: Advancement and prospects. Fuel 2022, 321, 124107. [Google Scholar] [CrossRef]
  14. Pham, T.P.T.; Kaushik, R.; Parshetti, G.K.; Mahmood, R.; Balasubramanian, R. Food waste-to-energy conversion technologies: Current status and future directions. Waste Manag. 2015, 38, 399–408. [Google Scholar] [CrossRef]
  15. Jawad, M.; Schoop, R.; Suter, A.; Klein, P.; Eccles, R. Perfil de eficacia y seguridad de Echinacea purpurea en la prevención de episodios de resfriado común: Estudio clínico aleatorizado, doble ciego y controlado con placebo. Rev. Fitoter. 2013, 13, 125–135. [Google Scholar]
  16. Verma, N.; Kumar, V. Microbial conversion of waste biomass into bioethanol: Current challenges and future prospects. Biomass Convers. Biorefinery 2021, 13, 6419–6456. [Google Scholar]
  17. Anca-Couce, A. Reaction mechanisms and multi-scale modelling of lignocellulosic biomass pyrolysis. Prog. Energy Combust. Sci. 2016, 53, 41–79. [Google Scholar]
  18. Zabed, H.; Sahu, J.N.; Boyce, A.N.; Faruq, G. Fuel ethanol production from lignocellulosic biomass: An overview on feedstocks and technological approaches. Renew. Sustain. Energy Rev. 2016, 66, 751–774. [Google Scholar] [CrossRef]
  19. Ren, J.; Liu, Y.L.; Zhao, X.Y.; Cao, J.P. Biomass thermochemical conversion: A review on tar elimination from biomass catalytic gasification. J. Energy Inst. 2020, 93, 1083–1098. [Google Scholar] [CrossRef]
  20. Zheng, H.; Wang, Y.; Feng, X.; Li, S.; Leong, Y.K.; Chang, J.S. Renewable biohydrogen production from straw biomass—Recent advances in pretreatment/hydrolysis technologies and future development. Int. J. Hydrogen Energy 2022, 47, 37359–37373. [Google Scholar] [CrossRef]
  21. Sarker, T.R.; Pattnaik, F.; Nanda, S.; Dalai, A.K.; Meda, V.; Naik, S. Hydrothermal pretreatment technologies for lignocellulosic biomass: A review of steam explosion and subcritical water hydrolysis. Chemosphere 2021, 284, 131372. [Google Scholar] [CrossRef]
  22. Nizami, A.S.; Rehan, M.; Waqas, M.; Naqvi, M.; Ouda, O.K.M.; Shahzad, K.; Miandad, R.; Khan, M.Z.; Syamsiro, M.; Ismail, I.M.I.; et al. Waste biorefineries: Enabling circular economies in developing countries. Bioresour. Technol. 2017, 241, 1101–1117. [Google Scholar] [CrossRef] [PubMed]
  23. Castaldi, M.; van Deventer, J.; Lavoie, J.M.; Legrand, J.; Nzihou, A.; Pontikes, Y.; Py, X.; Vandecasteele, C.; Vasudevan, P.T.; Verstraete, W. Progress and Prospects in the Field of Biomass and Waste to Energy and Added-Value Materials. Waste Biomass Valorization 2017, 8, 1875–1884. [Google Scholar] [CrossRef] [Green Version]
  24. Budi, S.; Ahmad, A.; Sakinah, N.; Said, M.; Fauzul, M.; Rozaimah, S.; Abdullah, S.; Razi, A.; Fitri, I.; Abu, H. Science of the Total Environment Macrophytes as wastewater treatment agents: Nutrient uptake and potential of produced biomass utilization toward circular economy initiatives. Sci. Total Environ. 2021, 790, 148219. [Google Scholar] [CrossRef]
  25. Wang, T.; Zhai, Y.; Zhu, Y.; Li, C.; Zeng, G. A review of the hydrothermal carbonization of biomass waste for hydrochar formation: Process conditions, fundamentals, and physicochemical properties. Renew. Sustain. Energy Rev. 2018, 90, 223–247. [Google Scholar] [CrossRef]
  26. Shi, X.; Ronsse, F.; Pieters, J.G. Finite element modeling of intraparticle heterogeneous tar conversion during pyrolysis of woody biomass particles. Fuel Process. Technol. 2016, 148, 302–316. [Google Scholar] [CrossRef]
  27. Saleem, M. Heliyon Possibility of utilizing agriculture biomass as a renewable and sustainable future energy source. Heliyon 2022, 8, e08905. [Google Scholar] [CrossRef]
  28. Cai, J.; He, Y.; Yu, X.; Banks, S.W.; Yang, Y.; Zhang, X.; Yu, Y.; Liu, R.; Bridgwater, A.V. Review of physicochemical properties and analytical characterization of lignocellulosic biomass. Renew. Sustain. Energy Rev. 2017, 76, 309–322. [Google Scholar] [CrossRef] [Green Version]
  29. Vaskalis, I.; Skoulou, V.; Stavropoulos, G.; Zabaniotou, A. Towards Circular Economy Solutions for The Management of Rice Processing Residues to Bioenergy via Gasification. Sustainability 2019, 11, 6433. [Google Scholar] [CrossRef] [Green Version]
  30. Song, C.; Zhang, C.; Zhang, S.; Lin, H.; Kim, Y.; Ramakrishnan, M.; Du, Y.; Zhang, Y.; Zheng, H.; Barceló, D. Science of the Total Environment Thermochemical liquefaction of agricultural and forestry wastes into biofuels and chemicals from circular economy perspectives. Sci. Total Environ. 2020, 749, 141972. [Google Scholar] [CrossRef]
  31. Velvizhi, G.; Balakumar, K.; Shetti, N.P.; Ahmad, E.; Kishore, K.; Aminabhavi, M. Bioresource Technology Integrated biorefinery processes for conversion of lignocellulosic biomass to value added materials: Paving a path towards circular economy. Bioresour. Technol. 2022, 343, 126151. [Google Scholar] [CrossRef]
  32. Chang, K.; Lou, K.; Ko, C. Potential of bioenergy production from biomass wastes of rice paddies and forest sectors in Taiwan. J. Clean. Prod. 2019, 206, 460–476. [Google Scholar] [CrossRef]
  33. Acharya, B.; Sule, I.; Dutta, A. A review on advances of torrefaction technologies for biomass processing. Biomass Convers. Biorefinery 2012, 2, 349–369. [Google Scholar] [CrossRef]
  34. Alanya-Rosenbaum, S.; Bergman, R.D. Life-cycle impact and exergy based resource use assessment of torrefied and non-torrefied briquette use for heat and electricity generation. J. Clean. Prod. 2019, 233, 918–931. [Google Scholar] [CrossRef]
  35. Rasheed, T.; Anwar, M.T.; Ahmad, N.; Sher, F.; Khan, S.U.D.; Ahmad, A.; Khan, R.; Wazeer, I. Valorisation and emerging perspective of biomass based waste-to-energy technologies and their socio-environmental impact: A review. J. Environ. Manag. 2021, 287, 112257. [Google Scholar] [CrossRef] [PubMed]
  36. Beyene, H.D.; Werkneh, A.A.; Ambaye, T.G. Current updates on waste to energy (WtE) technologies: A review. Renew. Energy Focus 2018, 24, 1–11. [Google Scholar] [CrossRef]
  37. Suopajärvi, H.; Umeki, K.; Mousa, E.; Hedayati, A.; Romar, H.; Kemppainen, A.; Wang, C.; Phounglamcheik, A.; Tuomikoski, S.; Norberg, N.; et al. Use of biomass in integrated steelmaking—Status quo, future needs and comparison to other low-CO2 steel production technologies. Appl. Energy 2018, 213, 384–407. [Google Scholar] [CrossRef] [Green Version]
  38. Rodionova, M.V.; Bozieva, A.M.; Zharmukhamedov, S.K.; Leong, Y.K.; Chi-Wei Lan, J.; Veziroglu, A.; Veziroglu, T.N.; Tomo, T.; Chang, J.S.; Allakhverdiev, S.I. A comprehensive review on lignocellulosic biomass biorefinery for sustainable biofuel production. Int. J. Hydrog. Energy 2022, 47, 1481–1498. [Google Scholar] [CrossRef]
  39. Zhang, F.; Zhao, Y.; Wang, D.; Yan, M.; Zhang, J.; Zhang, P.; Ding, T.; Chen, L.; Chen, C. Current technologies for plastic waste treatment: A review. J. Clean. Prod. 2021, 282, 124523. [Google Scholar] [CrossRef]
  40. Demirbaş, A. Current technologies for the thermo-conversion of biomass into fuels and chemicals. Energy Sources 2004, 26, 715–730. [Google Scholar] [CrossRef]
  41. Shen, Y.; Wang, J.; Ge, X.; Chen, M. By-products recycling for syngas cleanup in biomass pyrolysis—An overview. Renew. Sustain. Energy Rev. 2016, 59, 1246–1268. [Google Scholar] [CrossRef]
  42. Shen, Y.; Jarboe, L.; Brown, R.; Wen, Z. A thermochemical-biochemical hybrid processing of lignocellulosic biomass for producing fuels and chemicals. Biotechnol. Adv. 2015, 33, 1799–1813. [Google Scholar] [CrossRef] [PubMed]
  43. Kumar, G.; Dharmaraja, J.; Arvindnarayan, S.; Shoban, S.; Bakonyi, P.; Saratale, G.D.; Nemestóthy, N.; Bélafi-Bakó, K.; Yoon, J.J.; Kim, S.H. A comprehensive review on thermochemical, biological, biochemical and hybrid conversion methods of bio-derived lignocellulosic molecules into renewable fuels. Fuel 2019, 251, 352–367. [Google Scholar] [CrossRef]
  44. Papari, S.; Hawboldt, K. A review on the pyrolysis of woody biomass to bio-oil: Focus on kinetic models. Renew. Sustain. Energy Rev. 2015, 52, 1580–1595. [Google Scholar] [CrossRef]
  45. Yanik, J.; Kornmayer, C.; Saglam, M.; Yüksel, M. Fast pyrolysis of agricultural wastes: Characterization of pyrolysis products. Fuel Process. Technol. 2007, 88, 942–947. [Google Scholar] [CrossRef]
  46. Brammer, J.G.; Bridgwater, A.V. Drying technologies for an integrated gasification bio-energy plant. Renew. Sustain. Energy Rev. 1999, 3, 243–289. [Google Scholar] [CrossRef]
  47. Perkins, G.; Bhaskar, T.; Konarova, M. Process development status of fast pyrolysis technologies for the manufacture of renewable transport fuels from biomass. Renew. Sustain. Energy Rev. 2018, 90, 292–315. [Google Scholar] [CrossRef]
  48. Butler, E.; Devlin, G.; Meier, D.; McDonnell, K. A review of recent laboratory research and commercial developments in fast pyrolysis and upgrading. Renew. Sustain. Energy Rev. 2011, 15, 4171–4186. [Google Scholar] [CrossRef] [Green Version]
  49. Ly, H.V.; Kim, S.S.; Woo, H.C.; Choi, J.H.; Suh, D.J.; Kim, J. Fast pyrolysis of macroalga Saccharina japonica in a bubbling fluidized-bed reactor for bio-oil production. Energy 2015, 93, 1436–1446. [Google Scholar] [CrossRef]
  50. Li, M.F.; Sun, S.N.; Xu, F.; Sun, R.C. Organosolv Fractionation of Lignocelluloses for Fuels, Chemicals and Materials: A Biorefinery Processing Perspective; Springer: Berlin/Heidelberg, Germany, 2012; pp. 341–379. [Google Scholar]
  51. Tripathi, M.; Sahu, J.N.; Ganesan, P. Effect of process parameters on production of biochar from biomass waste through pyrolysis: A review. Renew. Sustain. Energy Rev. 2016, 55, 467–481. [Google Scholar] [CrossRef]
  52. Goyal, H.B.; Seal, D.; Saxena, R.C. Bio-fuels from thermochemical conversion of renewable resources: A review. Renew. Sustain. Energy Rev. 2008, 12, 504–517. [Google Scholar] [CrossRef]
  53. Kan, T.; Strezov, V.; Evans, T.J. Lignocellulosic biomass pyrolysis: A review of product properties and effects of pyrolysis parameters. Renew. Sustain. Energy Rev. 2016, 57, 1126–1140. [Google Scholar] [CrossRef]
  54. Patel, M.; Zhang, X.; Kumar, A. Techno-economic and life cycle assessment on lignocellulosic biomass thermochemical conversion technologies: A review. Renew. Sustain. Energy Rev. 2016, 53, 1486–1499. [Google Scholar] [CrossRef]
  55. Lee, Y.; Eum, P.R.B.; Ryu, C.; Park, Y.K.; Jung, J.H.; Hyun, S. Characteristics of biochar produced from slow pyrolysis of Geodae-Uksae 1. Bioresour. Technol. 2013, 130, 345–350. [Google Scholar] [CrossRef] [PubMed]
  56. Cozier, M. Business highlights: Collaboration: Bigger and beta. Biofuels, Bioprod. Biorefining 2014, 8, 743. [Google Scholar]
  57. Patra, B.R.; Nanda, S.; Dalai, A.K.; Meda, V. Slow pyrolysis of agro-food wastes and physicochemical characterization of biofuel products. Chemosphere 2021, 285, 131431. [Google Scholar] [CrossRef]
  58. Bi, R.; Zhang, Y.; Jiang, X.; Yang, H.; Yan, K.; Han, M.; Li, W.; Zhong, H.; Tan, X.; Xia, L.; et al. Simulation and techno-economical analysis on the pyrolysis process of waste tire. Energy 2022, 260, 125039. [Google Scholar] [CrossRef]
  59. Czajczyńska, D.; Ahmad, D.; Krzyżyńska, R.; Jouhara, H.; Rutkowski, P. Products’ composition of food waste low-temperature slow pyrolysis. In Proceedings of the 10th Conference on Interdisciplinary Problems in Environmental Protection and Engineering EKO-DOK 2018, Polanica-Zdroj, Poland, 16–18 April 2018; Volume 44, pp. 1–8. [Google Scholar] [CrossRef] [Green Version]
  60. Mondal, S.; Mondal, A.K.; Chintala, V.; Tauseef, S.M.; Kumar, S.; Pandey, J.K. Thermochemical pyrolysis of biomass using solar energy for efficient biofuel production: A review. Biofuels 2021, 12, 125–134. [Google Scholar] [CrossRef]
  61. Chai, Y.; Chen, A.; Bai, M.; Peng, L.; Shao, J.; Yuan, J.; Shang, C.; Zhang, J.; Huang, H.; Peng, C. Valorization of heavy metal contaminated biomass: Recycling and expanding to functional materials. J. Clean. Prod. 2022, 366, 132771. [Google Scholar] [CrossRef]
  62. Kumar, M.; Olajire Oyedun, A.; Kumar, A. A review on the current status of various hydrothermal technologies on biomass feedstock. Renew. Sustain. Energy Rev. 2018, 81, 1742–1770. [Google Scholar] [CrossRef]
  63. Cao, L.; Zhang, C.; Chen, H.; Tsang, D.C.W.; Luo, G.; Zhang, S.; Chen, J. Hydrothermal liquefaction of agricultural and forestry wastes: State-of-the-art review and future prospects. Bioresour. Technol. 2017, 245, 1184–1193. [Google Scholar] [CrossRef]
  64. de Caprariis, B.; De Filippis, P.; Petrullo, A.; Scarsella, M. Hydrothermal liquefaction of biomass: Influence of temperature and biomass composition on the bio-oil production. Fuel 2017, 208, 618–625. [Google Scholar] [CrossRef]
  65. Banu, J.R.; Sharmila, V.G.; Ushani, U.; Amudha, V.; Kumar, G. Impervious and influence in the liquid fuel production from municipal plastic waste through thermo-chemical biomass conversion technologies—A review. Sci. Total Environ. 2020, 718, 137287. [Google Scholar] [CrossRef] [PubMed]
  66. Molino, A.; Chianese, S.; Musmarra, D. Biomass gasification technology: The state of the art overview. J. Energy Chem. 2016, 25, 10–25. [Google Scholar] [CrossRef]
  67. Alonso, D.M.; Bond, J.Q.; Dumesic, J.A. Catalytic conversion of biomass to biofuels. Green Chem. 2010, 12, 1493–1513. [Google Scholar] [CrossRef]
  68. Dang, Q.; Zhang, X.; Zhou, Y.; Jia, X. Prediction and optimization of syngas production from a kinetic-based biomass gasification process model. Fuel Process. Technol. 2021, 212, 106604. [Google Scholar] [CrossRef]
  69. Ahmad, A.A.; Zawawi, N.A.; Kasim, F.H.; Inayat, A.; Khasri, A. Assessing the gasification performance of biomass: A review on biomass gasification process conditions, optimization and economic evaluation. Renew. Sustain. Energy Rev. 2016, 53, 1333–1347. [Google Scholar] [CrossRef]
  70. Chan, Y.H.; Cheah, K.W.; How, B.S.; Loy, A.C.; Shahbaz, M.; Singh, H.K.; Shuhaili, A.F.; Yusup, S.; Ghani, W.A.; Rambli, J.; et al. An overview of biomass thermochemical conversion technologies in Malaysia. Sci. Total Environ. 2019, 680, 105–123. [Google Scholar]
  71. Negro, S.O.; Suurs, R.A.A.; Hekkert, M.P. The bumpy road of biomass gasification in the Netherlands: Explaining the rise and fall of an emerging innovation system. Technol. Forecast. Soc. Change 2008, 75, 57–77. [Google Scholar] [CrossRef] [Green Version]
  72. Safarian, S.; Unnþórsson, R.; Richter, C. A review of biomass gasification modelling. Renew. Sustain. Energy Rev. 2019, 110, 378–391. [Google Scholar] [CrossRef]
  73. Karimi-Maleh, H.; Rajendran, S.; Vasseghian, Y.; Dragoi, E.N. Advanced integrated nanocatalytic routes for converting biomass to biofuels: A comprehensive review. Fuel 2022, 314, 122762. [Google Scholar] [CrossRef]
  74. Pang, S. Advances in thermochemical conversion of woody biomass to energy, fuels and chemicals. Biotechnol. Adv. 2019, 37, 589–597. [Google Scholar] [CrossRef]
  75. Tekin, K.; Karagöz, S.; Bektaş, S. A review of hydrothermal biomass processing. Renew. Sustain. Energy Rev. 2014, 40, 673–687. [Google Scholar] [CrossRef]
  76. Zhang, L.; Xu, C.; Champagne, P. Overview of recent advances in thermo-chemical conversion of biomass. Energy Convers. Manag. 2010, 51, 969–982. [Google Scholar] [CrossRef]
  77. Nunes, L.J.R.; Matias, J.C.O.; Catalão, J.P.S. Mixed biomass pellets for thermal energy production: A review of combustion models. Appl. Energy 2014, 127, 135–140. [Google Scholar] [CrossRef]
  78. Olugbade, T.O.; Ojo, O.T. Biomass Torrefaction for the Production of High-Grade Solid Biofuels: A Review. Bioenergy Res. 2020, 13, 999–1015. [Google Scholar] [CrossRef]
  79. Niu, Y.; Lv, Y.; Lei, Y.; Liu, S.; Liang, Y.; Wang, D.; Hui, S. Biomass torrefaction: Properties, applications, challenges, and economy. Renew. Sustain. Energy Rev. 2019, 115, 109395. [Google Scholar] [CrossRef]
  80. Verma, M.; Godbout, S.; Brar, S.K.; Solomatnikova, O.; Lemay, S.P.; Larouche, J.P. Biofuels production from biomass by thermochemical conversion technologies. Int. J. Chem. Eng. 2012, 2012, 542426. [Google Scholar] [CrossRef] [Green Version]
  81. Batidzirai, B.; Valk, M.; Wicke, B.; Junginger, M.; Daioglou, V.; Euler, W.; Faaij, A.P.C. Current and future technical, economic and environmental feasibility of maize and wheat residues supply for biomass energy application: Illustrated for South Africa. Biomass Bioenergy 2016, 92, 106–129. [Google Scholar] [CrossRef] [Green Version]
  82. Siwal, S.S.; Zhang, Q.; Devi, N.; Saini, A.K.; Saini, V.; Pareek, B.; Gaidukovs, S.; Thakur, V.K. Recovery processes of sustainable energy using different biomass and wastes. Renew. Sustain. Energy Rev. 2021, 150, 111483. [Google Scholar] [CrossRef]
  83. Huo, J.; Shanks, B.H. Bioprivileged Molecules: Integrating Biological and Chemical Catalysis for Biomass Conversion. Annu. Rev. Chem. Biomol. Eng. 2020, 11, 63–85. [Google Scholar] [CrossRef] [Green Version]
  84. Dziike, F.; Linganiso, L.Z.; Mpongwana, N.; Legodi, L.M.; Support, P.; Africa, S.; Africa, S.; Dziike, F. Biomass conversion into recyclable strong materials. South Afr. J. Sci. 2022, 118, 1–8. [Google Scholar] [CrossRef]
  85. Antoniou, N.; Monlau, F.; Sambusiti, C.; Ficara, E.; Barakat, A.; Zabaniotou, A. Contribution to Circular Economy options of mixed agricultural wastes management: Coupling anaerobic digestion with gasi fi cation for enhanced energy and material recovery. J. Clean. Prod. 2019, 209, 505–514. [Google Scholar] [CrossRef]
  86. Holtzapple, M.T.; Wu, H.; Weimer, P.J.; Dalke, R.; Granda, C.B.; Mai, J.; Urgun-Demirtas, M. Microbial communities for valorizing biomass using the carboxylate platform to produce volatile fatty acids: A review. Bioresour. Technol. 2022, 344, 126253. [Google Scholar] [CrossRef]
  87. Chojnacka, K.; Moustakas, K.; Witek-krowiak, A. Bioresource Technology Bio-based fertilizers: A practical approach towards circular economy. Bioresour. Technol. 2020, 295, 122223. [Google Scholar] [CrossRef]
  88. Lu, W.; Alam, M.A.; Luo, W.; Asmatulu, E. Integrating Spirulina platensis cultivation and aerobic composting exhaust for carbon mitigation and biomass production. Bioresour. Technol. 2019, 271, 59–65. [Google Scholar] [CrossRef]
  89. Hossain, S.M.Z. Biochemical Conversion of Microalgae Biomass into Biofuel. Chem. Eng. Technol. 2019, 42, 2594–2607. [Google Scholar] [CrossRef]
  90. Mielenz, J.R. Ethanol production from biomass: Technology and commercialization status. Curr. Opin. Microbiol. 2001, 4, 324–329. [Google Scholar] [CrossRef]
  91. Munasinghe, P.C.; Khanal, S.K. Biomass-derived syngas fermentation into biofuels: Opportunities and challenges. Bioresour. Technol. 2010, 101, 5013–5022. [Google Scholar] [CrossRef]
  92. Yilmaz, S.; Selim, H. A review on the methods for biomass to energy conversion systems design. Renew. Sustain. Energy Rev. 2013, 25, 420–430. [Google Scholar] [CrossRef]
  93. Sawatdeenarunat, C.; Surendra, K.C.; Takara, D.; Oechsner, H.; Khanal, S.K. Anaerobic digestion of lignocellulosic biomass: Challenges and opportunities. Bioresour. Technol. 2015, 178, 178–186. [Google Scholar] [CrossRef]
  94. Jingura, R.M.; Matengaifa, R. Optimization of biogas production by anaerobic digestion for sustainable energy development in Zimbabwe. Renew. Sustain. Energy Rev. 2009, 13, 1116–1120. [Google Scholar] [CrossRef]
  95. Themelis, N.J.; Ulloa, P.A. Methane generation in landfills. Renew. Energy 2007, 32, 1243–1257. [Google Scholar] [CrossRef]
  96. Roopnarain, A.; Adeleke, R. Current status, hurdles and future prospects of biogas digestion technology in Africa. Renew. Sustain. Energy Rev. 2017, 67, 1162–1179. [Google Scholar] [CrossRef]
  97. Tiwary, A.; Williams, I.D.; Pant, D.C.; Kishore, V.V.N. Emerging perspectives on environmental burden minimisation initiatives from anaerobic digestion technologies for community scale biomass valorisation. Renew. Sustain. Energy Rev. 2015, 42, 883–901. [Google Scholar] [CrossRef]
  98. Choudhary, P.; Assemany, P.P.; Naaz, F.; Bhattacharya, A.; de Siqueira Castro, J.; do Couto Couto, E.D.; Calijuri, M.L.; Pant, K.K.; Malik, A. A review of biochemical and thermochemical energy conversion routes of wastewater grown algal biomass. Sci. Total Environ. 2020, 726, 137961. [Google Scholar] [CrossRef]
  99. Pham, T.H.; Rabaey, K.; Aelterman, P.; Clauwaert, P.; De Schamphelaire, L.; Boon, N.; Verstraete, W. Microbial fuel cells in relation to conventional anaerobic digestion technology. Eng. Life Sci. 2006, 6, 285–292. [Google Scholar] [CrossRef]
  100. Balat, M. Biomass energy and biochemical conversion processing for fuels and chemicals. Energy Sources Part A Recover. Util. Environ. Eff. 2006, 28, 517–525. [Google Scholar] [CrossRef]
  101. Jia, X.; Qin, X.; Tian, X.; Zhao, Y.; Yang, T.; Huang, J. Inoculating with the microbial agents to start up the aerobic composting of mushroom residue and wood chips at low temperature. J. Environ. Chem. Eng. 2021, 9, 105294. [Google Scholar] [CrossRef]
  102. Wu, D.; Wei, Z.; Mohamed, T.A.; Zheng, G.; Qu, F.; Wang, F.; Zhao, Y.; Song, C. Lignocellulose biomass bioconversion during composting: Mechanism of action of lignocellulase, pretreatment methods and future perspectives. Chemosphere 2022, 286, 131635. [Google Scholar] [CrossRef]
  103. Vakili, M.; Rafatullah, M.; Ibrahim, M.H.; Salamatinia, B.; Gholami, Z.; Zwain, H.M. A review on composting of oil palm biomass. Environ. Dev. Sustain. 2015, 17, 691–709. [Google Scholar] [CrossRef]
  104. Omojola, A.; Ekiti, A.; Kallon, D. Impact of Fourth Industrial Revolution on Waste Biomass. In Proceedings of the SAIIE32 Steps, Muldersdrift, South Africa, 4–6 October 2021; pp. 1–14. [Google Scholar]
  105. Chundawat, S.P.S.; Beckham, G.T.; Himmel, M.E.; Dale, B.E. Deconstruction of lignocellulosic biomass to fuels and chemicals. Annu. Rev. Chem. Biomol. Eng. 2011, 2, 121–145. [Google Scholar] [CrossRef] [Green Version]
  106. Binod, P.; Janu, K.U.; Sindhu, R.; Pandey, A. Hydrolysis of Lignocellulosic Biomass for Bioethanol Production, 1st ed.; Elsevier: Amsterdam, The Netherlands, 2011. [Google Scholar]
  107. Makareviciene, V.; Sendzikiene, E. Application of Microalgae Biomass for Biodiesel Fuel Production. Energies 2022, 15, 4178. [Google Scholar] [CrossRef]
  108. Okajima, I.; Sako, T. Energy conversion of biomass with supercritical and subcritical water using large-scale plants. J. Biosci. Bioeng. 2014, 117, 1–9. [Google Scholar] [CrossRef] [PubMed]
  109. Guo, F.; Fang, Z.; Xu, C.C.; Smith, R.L. Solid acid mediated hydrolysis of biomass for producing biofuels. Prog. Energy Combust. Sci. 2012, 38, 672–690. [Google Scholar] [CrossRef]
  110. Zhou, N.; Zhang, Y.; Wu, X.; Gong, X.; Wang, Q. Hydrolysis of Chlorella biomass for fermentable sugars in the presence of HCl and MgCl2. Bioresour. Technol. 2011, 102, 10158–10161. [Google Scholar] [CrossRef]
  111. Wu, H.; Fu, Q.; Giles, R.; Bartle, J. Production of mallee biomass in Western Australia: Energy balance analysis. Energy Fuels 2008, 22, 190–198. [Google Scholar] [CrossRef]
  112. Gnanasekaran, L.; Priya, A.K.; Thanigaivel, S.; Hoang, T.K.A.; Soto-moscoso, M. The conversion of biomass to fuels via cutting-edge technologies: Explorations from natural utilization systems. Fuel 2023, 331, 125668. [Google Scholar] [CrossRef]
  113. Liguori, R.; Faraco, V. Bioresource Technology Biological processes for advancing lignocellulosic waste biorefinery by advocating circular economy. Bioresour. Technol. 2016, 215, 13–20. [Google Scholar] [CrossRef]
  114. Zhu, L.; O’Dwyer, J.P.; Chang, V.S.; Granda, C.B.; Holtzapple, M.T. Structural features affecting biomass enzymatic digestibility. Bioresour. Technol. 2008, 99, 3817–3828. [Google Scholar] [CrossRef]
  115. Yu, Z.; Gwak, K.S.; Treasure, T.; Jameel, H.; Chang, H.M.; Park, S. Effect of lignin chemistry on the enzymatic hydrolysis of woody biomass. ChemSusChem 2014, 7, 1942–1950. [Google Scholar] [CrossRef]
  116. Wyman, C.E.; Dale, B.E.; Elander, R.T.; Holtzapple, M.; Ladisch, M.R.; Lee, Y.Y. Coordinated development of leading biomass pretreatment technologies. Bioresour. Technol. 2005, 96, 1959–1966. [Google Scholar] [CrossRef] [PubMed]
  117. Yu, Z.; Jameel, H.; Chang, H.-M.; Park, S. The effect of delignification of forest biomass on enzymatic hydrolysis. Bioresour. Technol. 2011, 102, 9083–9089. [Google Scholar] [CrossRef] [PubMed]
  118. Shokrkar, H.; Ebrahimi, S.; Zamani, M. A review of bioreactor technology used for enzymatic hydrolysis of cellulosic materials. Cellulose 2018, 25, 6279–6304. [Google Scholar] [CrossRef]
  119. Dey, P.; Rangarajan, V.; Singh, J.; Nayak, J.; Dilip, K.J. Current perspective on improved fermentative production and purification of fungal cellulases for successful biorefinery applications: A brief review. Biomass Convers. Biorefinery 2022, 12, 967–995. [Google Scholar] [CrossRef]
  120. Park, J.Y.; Park, M.S.; Lee, Y.C.; Yang, J.W. Advances in direct transesterification of algal oils from wet biomass. Bioresour. Technol. 2015, 184, 267–275. [Google Scholar] [CrossRef]
  121. Hydrolysis, A.; Renewable, N. of Acid Hydrolysis of α-Cellulose. Appl. Biochem. Biotechnol. 2003, 105, 505–514. [Google Scholar]
  122. Wijaya, Y.P.; Putra, R.D.D.; Widyaya, V.T.; Ha, J.M.; Suh, D.J.; Kim, C.S. Comparative study on two-step concentrated acid hydrolysis for the extraction of sugars from lignocellulosic biomass. Bioresour. Technol. 2014, 164, 221–231. [Google Scholar] [CrossRef]
  123. Karpagam, R.; Jawaharraj, K.; Gnanam, R. Review on integrated biofuel production from microalgal biomass through the outset of transesterification route: A cascade approach for sustainable bioenergy. Sci. Total Environ. 2021, 766, 144236. [Google Scholar] [CrossRef]
  124. Roosta, A.; Sabzpooshan, I. Modeling the effects of cosolvents on biodiesel production. Fuel 2016, 186, 779–786. [Google Scholar] [CrossRef]
  125. Tsavatopoulou, V.D.; Aravantinou, A.F.; Manariotis, I.D. Biofuel conversion of Chlorococcum sp. and Scenedesmus sp. biomass by one- and two-step transesterification. Biomass Convers. Biorefinery 2021, 11, 1301–1309. [Google Scholar] [CrossRef]
  126. Boz, N.; Degirmenbasi, N.; Kalyon, D.M. Conversion of biomass to fuel: Transesterification of vegetable oil to biodiesel using KF loaded nano-γ-Al2O3 as catalyst. Appl. Catal. B Environ. 2009, 89, 590–596. [Google Scholar] [CrossRef]
  127. Castello, D.; Kruse, A.; Fiori, L. Low temperature supercritical water gasification of biomass constituents: Glucose/phenol mixtures. Biomass Bioenergy 2015, 73, 84–94. [Google Scholar] [CrossRef]
  128. Chen, Z.; Chen, H.; Xu, Y.; Hu, M.; Hu, Z.; Wang, J.; Pan, Z. Reactor for biomass conversion and waste treatment in supercritical water: A review. Renew. Sustain. Energy Rev. 2023, 171, 113031. [Google Scholar] [CrossRef]
  129. Feng, W.; Van Der Kooi, H.J.; De Swaan Arons, J. Biomass conversions in subcritical and supercritical water: Driving force, phase equilibria, and thermodynamic analysis. Chem. Eng. Process. Process Intensif. 2004, 43, 1459–1467. [Google Scholar] [CrossRef]
  130. Orisaleye, J.I.; Jekayinfa, S.O.; Dittrich, C.; Obi, O.F.; Pecenka, R. Effects of Feeding Speed and Temperature on Properties of Briquettes from Poplar Wood Using a Hydraulic Briquetting Press. Resources 2023, 12, 12. [Google Scholar] [CrossRef]
  131. Sharma, M.K.; Priyank, G.; Sharma, N. Biomass Briquette Production: A Propagation of Non-Convention Technology and Future of Pollution Free Thermal Energy Sources Manoj Kumar Sharma, Gohil Priyank, Nikita Sharma American Journal of Engineering Research. Am. J. Eng. Res. 2015, 4, 44–50. [Google Scholar]
  132. Adeleke, A.A.; Ikubanni, P.P.; Orhadahwe, T.A.; Christopher, C.T.; Akano, J.M.; Agboola, O.O.; Adegoke, S.O.; Balogun, A.O.; Ibikunle, R.A. Heliyon Sustainability of multifaceted usage of biomass: A review. Heliyon 2021, 7, e08025. [Google Scholar] [CrossRef]
  133. Sorita, G.D.; Favaro, S.P.; Ambrosi, A.; Di Luccio, M. Aqueous extraction processing: An innovative and sustainable approach for recovery of unconventional oils. Trends Food Sci. Technol. 2023, 133, 99–113. [Google Scholar] [CrossRef]
  134. Xiu, Z.L.; Zeng, A.P. Present state and perspective of downstream processing of biologically produced 1,3-propanediol and 2,3-butanediol. Appl. Microbiol. Biotechnol. 2008, 78, 917–926. [Google Scholar] [CrossRef]
  135. Tekle Asresu, A. Biomass Briquetting: Opportunities for the Transformation of Traditional Biomass Energy in Ethiopia. J. Energy Technol. Policy 2017, 7, 46–54. [Google Scholar]
  136. Ndiema, C.K.W.; Manga, P.N.; Ruttoh, C.R. Influence of die pressure on relaxation characteristics of briquetted biomass. Energy Convers. Manag. 2002, 43, 2157–2161. [Google Scholar] [CrossRef]
  137. Velusamy, S.; Subbaiyan, A.; Shanmugamoorthy, M.; Thirumoorthy, P. Characterization of solid biomass briquette biofuel from the wastes of Senna auriculata and Ricinus communis using Tapioca starch for sustainable environment. Environ. Sci. Pollut. Res. 2022, 30, 10110–10127. [Google Scholar] [CrossRef]
  138. Oladeji, J. Theoretical sspects of biomass briquetting: A Review Study. J. Energy Technol. Policy 2015, 5, 72–82. [Google Scholar]
  139. Dinesha, P.; Kumar, S.; Rosen, M.A. Biomass Briquettes as an Alternative Fuel: A Comprehensive Review. Energy Technol. 2019, 7, 1–8. [Google Scholar] [CrossRef]
  140. Velusamy, S.; Subbaiyan, A.; Thangam, R.S. Combustion characteristics of briquette fuels from sorghum panicle–pearl millets using cassava starch binder. Environ. Sci. Pollut. Res. 2021, 28, 21471–21485. [Google Scholar] [CrossRef]
  141. Fajfrlíková, P.; Brunerová, A.; Roubík, H. Analyses of waste treatment in rural areas of east java with the possibility of low-pressure briquetting press application. Sustainability 2020, 12, 8153. [Google Scholar] [CrossRef]
  142. Bot, B.V.; Sosso, O.T.; Tamba, J.G.; Lekane, E.; Bikai, J.; Ndame, M.K. Preparation and characterization of biomass briquettes made from banana peels, sugarcane bagasse, coconut shells and rattan waste. Biomass Convers. Biorefinery 2021, 13, 7937–7946. [Google Scholar] [CrossRef]
  143. Bot, B.V.; Tamba, J.G.; Sosso, O.T. Assessment of biomass briquette energy potential from agricultural residues in Cameroon. Biomass Convers. Biorefinery 2022, 1–13. [Google Scholar] [CrossRef]
  144. Kpalo, S.Y.; Zainuddin, M.F.; Manaf, L.A.; Roslan, A.M. A review of technical and economic aspects of biomass briquetting. Sustainability 2020, 12, 4609. [Google Scholar] [CrossRef]
  145. Kumar, A.; Kumar, N.; Baredar, P.; Shukla, A. A review on biomass energy resources, potential, conversion and policy in India. Renew. Sustain. Energy Rev. 2015, 45, 530–539. [Google Scholar] [CrossRef]
  146. Thatoi, H.; Dash, P.K.; Mohapatra, S.; Swain, M.R. Bioethanol production from tuber crops using fermentation technology: A review. Int. J. Sustain. Energy 2016, 35, 443–468. [Google Scholar] [CrossRef]
  147. Hameed, Z.; Aslam, M.; Khan, Z.; Maqsood, K.; Atabani, A.E.; Ghauri, M.; Khurram, M.S.; Rehan, M.; Nizami, A.S. Gasification of municipal solid waste blends with biomass for energy production and resources recovery: Current status, hybrid technologies and innovative prospects. Renew. Sustain. Energy Rev. 2021, 136, 110375. [Google Scholar] [CrossRef]
  148. Khalil, M.; Berawi, M.A.; Heryanto, R.; Rizalie, A. Waste to energy technology: The potential of sustainable biogas production from animal waste in Indonesia. Renew. Sustain. Energy Rev. 2019, 105, 323–331. [Google Scholar] [CrossRef]
  149. Seo, M.W.; Lee, S.H.; Nam, H.; Lee, D.; Tokmurzin, D.; Wang, S.; Park, Y.K. Recent advances of thermochemical conversieon processes for biorefinery. Bioresour. Technol. 2022, 343, 126109. [Google Scholar] [CrossRef]
  150. Sansaniwal, S.K.; Rosen, M.A.; Tyagi, S.K. Global challenges in the sustainable development of biomass gasification: An overview. Renew. Sustain. Energy Rev. 2017, 80, 23–43. [Google Scholar] [CrossRef]
  151. Mirmoshtaghi, G.; Skvaril, J.; Campana, P.E.; Li, H.; Thorin, E.; Dahlquist, E. The influence of different parameters on biomass gasification in circulating fluidized bed gasifiers. Energy Convers. Manag. 2016, 126, 110–123. [Google Scholar] [CrossRef]
  152. Rodionova, M.V.; Poudyal, R.S.; Tiwari, I.; Voloshin, R.A.; Zharmukhamedov, S.K.; Nam, H.G.; Zayadan, B.K.; Bruce, B.D.; Hou, H.J.M.; Allakhverdiev, S.I. Biofuel production: Challenges and opportunities. Int. J. Hydrogen Energy 2017, 42, 8450–8461. [Google Scholar] [CrossRef]
  153. Tshikovhi, A.; Mishra, S.B.; Mishra, A.K. International Journal of Biological Macromolecules Nanocellulose-based composites for the removal of contaminants from wastewater. Int. J. Biol. Macromol. 2020, 152, 616–632. [Google Scholar] [CrossRef]
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Figure 1. Summary of biomass conversion technologies.
Figure 1. Summary of biomass conversion technologies.
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Figure 2. Representation of the pyrolysis process [36]. Reprinted with permission from Ref. [36]. Copyright 2018 Elsevier.
Figure 2. Representation of the pyrolysis process [36]. Reprinted with permission from Ref. [36]. Copyright 2018 Elsevier.
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Figure 3. Conceptual fast pyrolysis process [15].
Figure 3. Conceptual fast pyrolysis process [15].
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Figure 4. Process schematic: biomass gasification and upgrading [67]. Reprinted with permission from Ref. [67]. Copyright 2010 Royal Society of Chemistry.
Figure 4. Process schematic: biomass gasification and upgrading [67]. Reprinted with permission from Ref. [67]. Copyright 2010 Royal Society of Chemistry.
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Figure 5. Gasification process steps [72]. Reprinted with permission from Ref. [72]. Copyright 2019 Elsevier.
Figure 5. Gasification process steps [72]. Reprinted with permission from Ref. [72]. Copyright 2019 Elsevier.
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Figure 6. Products formed during the torrefaction process [33]. Reprinted with permission from Ref. [33]. Copyright 2012 Springer Nature.
Figure 6. Products formed during the torrefaction process [33]. Reprinted with permission from Ref. [33]. Copyright 2012 Springer Nature.
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Table 1. Advantages and disadvantages of biomass conversion technologies.
Table 1. Advantages and disadvantages of biomass conversion technologies.
TechnologyAdvantagesDisadvantagesReferences
ThermochemicalIts fast reaction and takes seconds or minutes to be completedHigh energy usage and hazardous conditions[12,13]
BiologicalAmbient pressure and temperature, waste material variety, no CO2 accumulation, and cost-effectivenessSlow process and can take hours, days, weeks, or years to be completed[14,15]
BiochemicalRequires less external energy inputThe challenging structural veracity of plant cell wall materials aimed to attack the degradation of microbial[16,17]
PhysicalEasy handling and less consumption of chemicalsHigh energy consumption and not economically feasible[18]
Table 2. Thermochemical technologies.
Table 2. Thermochemical technologies.
TechnologyBiomass TypeProductTemperature (°C)AdvantagesDisadvantagesReferences
PyrolysisLignocellulosic biomassBio-oil, biochar, and syngas500–1000High efficiency, flexibility, and high-quality fuelHigh operational and investment cost[24,25,26]
Hydrothermal liquefactionAlgae, animal manure, etc.Bio-oil gases300–350Feedstock versatility,
higher yield and quality bio-oil, capability to turn wet materials, and its beneficial environmental and economic potential		Energy consumption in high-pressure processes requires longer residence time and is expensive[12,27,28]
GasificationMunicipal plastic waste (MSP)Syngas800–1000Flexible, better emission control, various uses of produced syngasComplex multi-stage process and formation of tars and char[5,29,30]
CombustionWoodThermal energy800–1000The high calorific value of biomass and multiple fuel productionOnly feasible for biomass with moisture volume below 50%[31,32]
TorrefactionWoodSolid Fuel200–300Low energy, reduction in moisture, and increase in energy densityProcess control, upscaling, and sustainability difficulties[33,34]
IncinerationMunicipal solid waste (MSW)Heat, CO2900–1100Appropriate for high calorific
value, reduce volume and mass by up to
80% and 70%, respectively		Higher moisture, low energy content, high maintenance, and operating capital costs[35,36]
Table 3. Biological technologies.
Table 3. Biological technologies.
TechnologyBiomass TypeProductAdvantagesDisadvantagesReferences
FermentationMicroalgae biomassGrain alcoholLower cost, high ethanol yield, and short processing timeCannot use commonly used yeasts, recombinant microorganism instability, and techno-economic limitations[18,84]
Anaerobic digestionSewage sludge, livestock manureMethane, CO2, digestateEconomic costs and the safe disposal of digestateComplex products require additional processing to become refined products; storage and processing problems[85,86,87]
Aerobic compostingOrganic wasteHeatMinimizes animal manure quantity and kills microorganismsCauses secondary environmental pollution[8,88]
Table 4. Biochemical technologies.
Table 4. Biochemical technologies.
TechnologyBiomass TypeProductAdvantagesDisadvantagesReferences
Hydrolysislignocellulosic biomassSugars-ethanolModerate process temperature and does not need expensive enzymesToxic, hazardous, and corrosive[18,106]
TransesterificationMicroalgal biomassLiquid fuel, biodieselEnvironmentally friendly, low process temperature, and high ester yieldLong process and high purification product costs[27,107]
SCWGWaste plasticsHydrogenHigh reaction efficiency, H2 selectivity, and rapid reactionHigh-pressure operation[4,108]
Table 5. Physical technologies.
Table 5. Physical technologies.
TechnologyBiomass TypeProductAdvantagesDisadvantagesReferences
BriquettingAgricultural and forestry wasteFuel briquettesExtended transportation distances, reliable energy, and storage possibilitiesExpensive technology and high energy consumption[131,132]
ExtractionSeedsOilEnvironmentally friendly, safe, and low energy consumptionLarge-scale application challenges[133]
DistillationSeedsBio-oilSeparates components effectively and maximum yield is obtainedA large amount of energy consumption[134]
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Tshikovhi, A.; Motaung, T.E. Technologies and Innovations for Biomass Energy Production. Sustainability 2023, 15, 12121. https://doi.org/10.3390/su151612121

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Tshikovhi A, Motaung TE. Technologies and Innovations for Biomass Energy Production. Sustainability. 2023; 15(16):12121. https://doi.org/10.3390/su151612121

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Tshikovhi, Azwifunimunwe, and Tshwafo Ellias Motaung. 2023. "Technologies and Innovations for Biomass Energy Production" Sustainability 15, no. 16: 12121. https://doi.org/10.3390/su151612121

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Tshikovhi, A., & Motaung, T. E. (2023). Technologies and Innovations for Biomass Energy Production. Sustainability, 15(16), 12121. https://doi.org/10.3390/su151612121

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