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... gasification and pyrolysis are three thermal conversion processes by which energy is obtained from biomass. Distinctions between these three processes are summarized in Tables 2 and 3. In short, combustion occurs with sufficient oxygen to completely oxidize the fuel, i.e. convert all carbon to carbon dioxide, all hydrogen to water, and all the sulfur to sulfur dioxide. ...
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Experimental research of fuel-bed gasification at different heating rates was conducted. Release of four gases (CO, NO, H2O, CO2) was determined. Optimal heating rate mode for this method of gasification was established.
Citations
... -A 400 kW e gasification plant in Northern Italy fed by agriculture waste, biomass forestry, and food industry waste (Molino et al., 2016). -A facility in Prosser, Washington, where the feasibility of gasifying grape pomace and using the produced syngas to reduce by 40%, the use of fossil fuels for industrial drying has been demonstrated (Roos, 2010). ...
Food and Agriculture Organization of the United Nations (FAO) estimates that food, beverage, and tobacco sector is currently responsible for about 30% of total world energy consumption and approximately the same percentage of food is wasted during its industrial transformation. Improving the sustainability of food processing is fundamental to reduce the environmental impact of this sector as well as to lower the disposal cost of industrial waste. The objective of this work is to propose an efficient and technically feasible solution for the management and energy recovery of residual biomasses and industrial processing by-products, such as sewage sludge produced by industrial wastewater treatment. The above solution is developed for a real frozen food factory operating in Lazio region (Italy) introducing a sewage sludge dryer and a gasifier to produce syngas. The software Aspen Plus is adopted to numerically simulate the gasification process, using a literature validated model, while the dryer and the already present combined heat and power (CHP) plant are dynamically modelled in TRNSYS environment. The results demonstrate that the proposed solution is feasible and attractive from both an environmental and an economic perspective. The Simple Pay Back of the investment is less than 3 years, while the Net Present Value stands at about 2.4 M€. Furthermore, the CO2 proposed system allows to save 179 t of equivalent CO2 emissions compared to the current system.
... Gasification is a thermochemical conversion technology in which biomass is converted to a gaseous mixture of H 2 , CO, CH 4 , and CO 2 , referred to as syngas [93,94]. Gasification is performed at high temperatures (700-1200 • C) in the presence of a limited amount of oxidizing agent (i.e., air, steam, oxygen, carbon dioxide, or a combination of these) in insufficient amounts to reach combustion [95,96]. ...
... Currently, most of the olive stone produced are combusted to generate thermal energy [12]. Despite this, biomass gasification technology has gained increased interest over the past two decades due to higher efficiency and less carbon emissions than combustion [19,20]. Biomass gasification uses the by-products from the olive oil industry to simultaneously generate electricity and heat while reducing the amount of undesired waste in olive oil production. ...
... Hence, this technology is considered one of the best thermochemical conversion approaches. Through gasification, high-carbon raw material such as olive stone is partially oxidized in an anoxic environment and converted into a gaseous phase and a solid phase [20,21]. The gaseous phase, commonly known as syngas [20], is a valuable and convenient gas mixture that mainly consists of carbon monoxide (CO), hydrogen (H 2 ), methane (CH 4 ) and carbon dioxide (CO 2 ) as well as lighter and heavier hydrocarbons [22]. ...
... Through gasification, high-carbon raw material such as olive stone is partially oxidized in an anoxic environment and converted into a gaseous phase and a solid phase [20,21]. The gaseous phase, commonly known as syngas [20], is a valuable and convenient gas mixture that mainly consists of carbon monoxide (CO), hydrogen (H 2 ), methane (CH 4 ) and carbon dioxide (CO 2 ) as well as lighter and heavier hydrocarbons [22]. Syngas can be burnt for energy or utilized to synthesize other high-value chemicals [21,23]. ...
The rapid growth in biomass waste generation from industrial and agricultural sectors has emerged as a significant global challenge. One potential solution to address this challenge is to utilize biomass waste materials as sustainable construction materials, which can mitigate landfilling concerns, reduce the need for natural materials and ultimately minimize carbon emissions. This study focused on the evaluation of the engineering and environmental properties of olive stone biochar (OSB) as a green construction fill material. OSB is the solid residue resulting from biomass gasification in a waste-to-energy plant. The properties of OSB were compared to those of recycled glass (RG), a mainstream construction and demolition (C&D) waste material in Australia, for benchmarking purposes. Extensive laboratory tests were conducted on unbound OSB, RG and OSB/RG blends. The results indicated that gasified OSB was a stable biomass material and it exhibited good engineering performance when used as a construction fill material. In cases where higher strength was required, OSB can be blended with RG to achieve higher values of California bearing ratio (CBR) and resilient modulus. All OSB/RG blends were found to meet the minimum CBR requirement for subgrade materials as specified by the local road authority. Environmental tests revealed that the application of OSB as a construction fill material would not have any adverse environmental impact. This research highlighted the potential for OSB to replace virgin quarry materials in geotechnical fill and road subgrade applications. The involvement of biochar as a carbon sink in construction works also aligns well with the strategy to manufacture green materials within the construction industry, as it serves the dual purpose of locking carbon in a stable state within infrastructures and boosting waste reutilization rates simultaneously.
... In the scrubbing and cooling section, PG passes through a water scrubber where the PG temperature reduces toward ambient temperature, and circulating water tries to remove the contaminants, tar, and soot particles that are soluble in water from the PG. However, the tar content of waste feed materials in fixed downdraft gasifier ranges from 0.02 to 4 g/Nm 3 [61]. Besides, PG passed through a cyclone separator for further cleaning. ...
The gasifier-compression ignition engine (G-CIE) system has been an attractive alternative power source to generate decentralized
electricity and reduce ecological degradation. However, the major challenge of G-CIE system is to deal with the
performance-emission trade-off via operating settings, consequently, low power and efficiency. Hence, this study aims to
generate producer gas (PG) from the co-gasification of mahua wood and saw-dust briquette from the downdraft gasifier and
to determine the performance of the G-CIE system with dual-fueled diesel and PG. Furthermore, the novelty of this work
is to optimize G-CIE’s operating variables, such as gasification equivalence ratio (ER), engine compression ratio (CR),
and engine brake power (BP). To this end, a multi-objective optimization tool, response surface methodology (RSM), was
applied to employ optimization of the operating setting. Results reveal the optimum operational conditions as 0.10 gasification
ER, 16CR, and 3.18 kW engine BP. The corresponding performance responses are brake-specific fuel consumption
(BSFC) 0.1654 kg/kWh, brake thermal efficiency (BTE) 17.41%, sound intensity 91.74 db, CO 0.017% vol., HC 3.83 ppm,
CO2
3.11%vol., and NOx 1.85 ppm. Maximum diesel replacement observed was 44.76%, 54.28%, and 62.75% at CR 16, 17,
and 18, respectively. The average values obtained for R2 were 95–99% and 0.8380 composite desirabilities. Furthermore,
predicted performance responses were compared experimentally at optimized input conditions and found to be a 6.07%
maximum error. Thus, using RSM, the proper operating setting can be found, and results will be guided to end-users for
more diesel substitution and environmental protection.
... The mechanical strength of fuel particles prevents them from breaking under pressure and preserves the voids between the particles. Gasification and pyrolysis are more efficient when there are more empty spaces between fuel particles [39]. As shown in Figure 6, all the produced pellet types had acceptable strength except Plt1. ...
Seaweed can be a desirable source of renewable energy or fuel after it has been processed by combustion, thermochemical conversion by gasification, pyrolysis, or hydrothermal liquefaction (HTL) or biochemical conversion routes like anaerobic digestion (AD). This work explores how well the measured properties of seaweed pellets match the specifications for the various fuel and energy conversion options listed. Blends of hay, wood chips, sawdust, and seaweed were pelletized. Eight pellet blends with dominant seaweed content and minimum acceptable mechanical strength and stability were produced and their physical and chemical properties were reported. The seaweed pellets had an energy content of around 14 MJ/kg, and each pellet could withstand almost 200 N of compression force. Their water content was around 5% or less and their ash content was around 20–34%. According to the results, a higher wood content increased the energy content of the pellets. Among those properties measured in this project, none of them contradicted the typical specifications of combustion, HTL, and AD. However, the low water content and low strength of some pellet types were unable to meet the specifications for certain types of gasification and pyrolysis.
... Crop residues can also be used as feedstock for producing the gaseous fuels like producer gas and biogas (Ro et al., 2019;Tamburini et al., 2020). Crop residue with a moisture content of 50-60% can be used for generating the producer gas through updraft bed or fluidized bed gasifiers (Roos, 2010). The gasification of crop residue can produce the clean gaseous fuel with high energy conversion efficiency of 28-36% and calorific value of 4.5-6.0 ...
Crop residue crucially contributes in running the essential agro-environment services. The modernization in crop production with high yielding varieties substantially increased the crop residue and its management challenges. The critical window period between two crops like in wheat sowing after rice and sugarcane harvest and poor suitability of some crop residues for animal feed pushed the malpractice of crop residue burning especially in developing countries like India. In long-term, the practice of residue burning along with climate change phenomenon puts the serious challenges in maintaining the quality of natural resources and sustainable crop production system. The precious elements retained in the crop residue are lost upon burning and converted to harmful air pollutants which otherwise can run the essential services in soil-plant system and find industrial applications as feedstock if managed in a sustainable way. The present review article provides critical insights on the current status of residue production and in-situ management of crop residue via different routes using suitable machinery package along with relative advantages and challenges. The prospective of crop residue to derive the soil ameliorants through composting and thermal decomposition approaches are critically discussed in the present review study. Moreover, a brief account is presented on residue derived energy generation (liquid and gaseous fuels) through thermo-chemical and thermal decomposition processes, which can ease the burden of fossil fuels on environment as well as economy of the country. The review article also explores cutting-edge industrial application of crop residue, present challenges and future thrust areas to overcome such issues in the sustainable crop residue management.
... This entails the thermal decomposition of the volatile compounds of an organic substance when heated (350−600°C for pyrolysis; 800−1200°C for gasification) in the absence of oxygen. 24 Biochar is desirable because of its high surface area (∼300−600 m 2 g −1 ), though less than that of AC (∼900−1000 m 2 g −1 ). 19,22 Biochar performance is highly variable based on feedstock material and production process, with higher-temperature biochars exhibiting more favorable TrOC removal while lower-temperature biochars, which often contain increased number of polar functional groups on the biochar's surface, have inconsistent performance depending on material and manufacturing conditions. ...
Urban stormwater runoff is a significant driver of surface water quality impairment. Recently, attention has been drawn to potential beneficial use of urban stormwater runoff, including augmenting drinking water supply in water-stressed areas. However, beneficial use relies on improved treatment of stormwater runoff to remove mobile dissolved metals and trace organic contaminants (TrOCs). This study assesses six engineered media mixtures consisting of sand, zeolite, high-temperature gasification biochar, and regenerated activated carbon (RAC) for removing a suite of co-contaminants comprising five metals, three herbicides, four pesticides, a corrosion inhibitor, six per- and polyfluoroalkyl substances (PFASs), five polychlorinated biphenyls (PCBs), and six polycyclic aromatic hydrocarbons (PAHs). This long-term laboratory-scale column study uses a novel approach to generate reproducible synthetic stormwater that incorporates catch basin material and straw-derived dissolved organic carbon. Higher flow conditions (20 cm hr–1), larger sized media (0.42–1.68 mm), and downflow configuration with outlet control increase the relevance of this study to better enable implementation in the field. Biochar- and RAC-amended engineered media filters removed nearly all of the TrOCs in the effluent over the course of three months of continuous flow (480 empty bed volumes), while sample ports spaced at 25% and 50% along the column depth provide windows to observe contaminant transport. Biochar provided greater benefit to TrOC removal than RAC on a mass basis. This study used relatively high concentrations of contaminants and low biochar and RAC content to observe contaminant transport. Performance in the field is likely to be significantly better with higher biochar- and RAC-content filters and lower ambient stormwater contaminant concentrations. This study provides proof-of-concept for biochar- and RAC-amended engineered media filters operated at a flow rate of 20 cm hr–1 for removing dissolved TrOCs and metals and offers insights on the performance of biochar and RAC for improved stormwater treatment and field trials.
... Fluidised bed reactors are further divided into two categories: bubbling fluidised bed and circulating fluidised bed. Bubbling fluidised bed reactors can operate on a scale of up to a 25 MW th at approximately 800 °C, with a product gas containing moderate tar levels and high in particulates [186]. Circulating fluidised bed reactors can operate up to 100 MW th at temperatures of 850 °C, with a product gas also high in particulates but lower in tar. ...
... Circulating fluidised bed reactors can operate up to 100 MW th at temperatures of 850 °C, with a product gas also high in particulates but lower in tar. Fixed bed reactors operate on a smaller scale, with a downdraft fixed bed approximately 5 kW th to 2 MW th producing low tar and moderate particulates at 800 °C, while an updraft fixed bed can operate at > 10MW th producing very high tar but low particulates at a reaction temperature of 1000 °C [186]. Bubbling and circulating fluidised bed reactors are also commercial reactor technologies used for pyrolysis, providing a wide and shallow contact area between the solid and fluid, and presenting high reaction rates and heat transfer [187]. ...
... In addition to its higher efficiency and lower cost, gasification can accommodate a wider range of feedstocks than the other thermochemical routes, although generating a smaller range of products [197]. Although the liquid fuel produced through pyrolysis is more energy dense than the syngas produced through gasification, and subsequently, conventional transportation costs would be expected to be reduced, bio-oils corrosive nature results in heightened transportation and storage costs [186]. ...
Purpose
With its substantial CO 2 eq emissions, the agricultural sector is a significant greenhouse gas (GHG) emitter. Animal manure alone contributes 16% of the total agricultural emissions. With a rapidly increasing demand for animal-based protein, animal wastes are expected to rise if sustainable manure management practices are not implemented. Manures have the potential to be treated to generate valuable products (biofertiliser and biocrude) or feedstock for energy production. Thermochemical conversion technologies such as pyrolysis, combustion, supercritical gasification (SCWG), etc., have demonstrated their potential in manure management and valorisation. This study provides a broader overview of these technologies and envisages future manure valorisation trends.
Methods
The paper presents a state-of-the-art review of manure valorisation. Characterisation of manure, modelling and optimisation of thermochemical conversion technologies along with life cycle anaalysis (LCA) are also reviewed.
Results
The literature review highlighted that the thermochemical conversion technologies can generate bio-oils, syngas, H 2 , biofuels, heat, and biochar as carbon-free fertiliser. The reported calorific value of the produced bio-oil was in the range of 26 MJ/kg to 32 MJ/kg. However, thermochemical conversion technologies are yet to be commercialised. The major challenges associated with the scale-up of manure derived feedstocks are relatively high moisture and ash content, lower calorific value and higher concentration of impurities (N, Cl, and S). LCA studies conclude that gasification presents a sustainable option for manure valorisation as it is economical with modest environmental threats.
Significance of Study
This review briefly states the current challenges faced in manure management and presents the case for a sustainable valorisation of animal manures using thermochemical technologies. The economic, environmental and societal advantages of these technologies are presented in order to promote the scientific and industrial development of the subject in the academic and research community.
Conclusions
Thermochemical conversion technologies are promising for manure valorisation for energy and nutrient recovery. However, their commercialisation viability needs wide-ranging evaluations such as techno-economics, life-cycle analysis, technology take-up and identification of stakeholders. There should be clear-cut policies to support such technologies. It should be advocated amongst communities and industries, which necessitates marketing by the governments to secure a clean energy future for the planet.
Graphical Abstract
... Gas is easily distributed through existing pathways, has great combustion efficiency, can be burned autonomously, emits little emissions, and allowing for the realization of "smokeless cities" [15]. Based on the efficiency comparison, it is reported that, a biomass-fired steam turbine system's efficiency ranges from 20 to 25%, whereas syngas-fired engines and turbines can attain 30 to 40% system efficiencies, and even higher efficiencies are possible in integrated combined cycles [16]. Literature review points out that researchers from various geographical entities such as USA [17], Asia [1], Europe [18], and Australia [19] are of the vision that this technique might complement future needs of the world. ...
Partial oxidation of dried cattle dung cannot achieve temperatures necessary for endothermic reduction reactions in autothermal
gasification, because of lower fixed carbon (FC) content and higher volatility of feedstock. This study comprehends a simplified
and viable allothermal gasification of cattle dung in an integrated system. Solar photovoltaic (PV) induced air gasification of
dried cattle dung was carried out in a small-scale tubular furnace, equipped with controlled operating systems. Characterization
of cattle dung showed that it had a higher heating value (HHV) of 16 ±0.01 MJ/kg, volatile content of 63% ±1%wt, and FC
of 15 ± 1%wt. Gasification was performed at variable power supply levels (W) of the solar PV system and corresponding
temperatures with varying air–fuel equivalence ratios (ER = 0.21–0.3). The optimal fractions of hydrogen (13.26 ± 0.95%),
carbon monoxide (14.39 ± 1.2%), and methane (2.15 ± 0.5%) were achieved at 1100 W, 800 °C, and 0.26 ER. The HHV of
syngas was 4.89±0.4% MJ/Nm3 at optimal process conditions with an average yield of 2.20±0.001 m3/kg. Based on the solid
residue and thermal conversion efficiencies, 82.67 ± 1.2% of biomass was converted to syngas and 66.70 ± 2% of biomass
energy was extracted through gasification. This research provides a firm and novel foundation for a long term, efficient and
cost-effective hybrid gasification system capable of handling a wide range of high-volume biowaste feedstock, particularly
cattle dung.
... Biomass to energy convertion processes are seen in Figure 4. In combustion, sufficient or excess oxygen is needed for fully oxidizing the fuel and converting all carbon to carbondioxide, all hydrogen to water, and all sulfur to sulfurdioxide whereas gasification occurs with partial oxygen and pyrolysis occurs in the absence of oxygen (Roos, 2010). Liquefaction occurs at low temperatures (250-350 0 C) and high pressure whereas pyrolysis occurs at moderate to high temperatures (400-600 0 C) and atmospheric pressure (Jena and Das, 2011). ...
... Pyrolysis of rice straw produces (1) biogas, light hydrocarbon gasses, which can either be used for cooking and heating or indirectly used in an engine, (2) carbon rich biochar which can be used as solid fuel, activated carbon precursor, as soil conditioner and (3) biooil which is rich in alcohols, ethers, and aldehydes also reduces the emission of SO2 and NO2 compared to fossil fuels (Wageningen, 2013;Shoaib et al., 2018;Chakma et al., 2016;Roos, 2010). However, high ash and silica content of rice straw may cause boiler system and erosion problems in the machines (Wageningen, 2013;Van Hung et al., 2020). ...
... Difficult degradation of lignocellulosic structure can be achieved by adding fungi, acidic or alkaline solutions (Mussoline et al., 2013). Biochar as a soil conditioner, improves soil texture, holds moisture and releases fertilizers slowly (Roos, 2010). ...
