Investigating fouling deposition during combustion of hydrothermally treated palm empty fruit Bunch: Pilot-Scale study for industrial hydrothermal reactor.

Inorganic elements in palm empty fruit bunch (EFB) are problematic in boiler operation, causing slagging and fouling deposits. The first pilot-scale hydrothermal treatment (HTT) system was commenced in a palm oil mill to remove undesirable elements. Fuel properties, combustion behavior, and fouling deposition of HTT-EFB were investigated. Liquid temperatures and treatment times in the HTT system significantly altered EFB-fuel properties. At ≥ 60 °C, potassium removals of at least 78 % were achieved, generating EFB-fuel containing potassium below 0.5 %wt. Later, a series of EFB combustion experiments were conducted in a specially designed fixed-bed reactor to simulate the tube surface of industrial boilers. Fouling deposition from HTT-EFB combustion reduced to below half of untreated EFB at all HTT conditions and combustion temperatures studied. The deposit-to-fuel ratio of HTT-EFB combusted at 1,000 °C was 37.3 % lower than untreated EFB combusted at a typical EFB boiler at 800 °C. Results demonstrated great potential for HTT-EFB in industrial applications.

Evaluation of the Productivity and Potential Utilization of Artemisia dubia Plant Biomass for Energy Conversion.

Field studies with the large-stemmed plant Artemisia dubia (A. dubia) have been carried out at the Vezaiciai Branch of LAMMC since 2018. According to three years of experimental results, annual dry matter (DM) yield varied from 7.94 to 10.14 t ha-1. Growing conditions, nitrogen application level, and harvesting time had statistically significant impacts on A. dubia productivity. The most important tasks of this article were to investigate and determine the factors influencing A. dubia plant biomass productivity and the evaluation of technological, power, and environmental parameters of plant biomass utilization for energy conversion and the production of high-quality solid biofuel pellets. For the experiments, six variants of A. dubia samples were used, which were grown in 2021. Plants were cut three times and two fertilization options were used: (1) no fertilization and (2) fertilization with 180 kg ha-1 of nitrogen fertilizer. These harvested plants were chopped, milled, and pressed into pellets. The physical-mechanical characteristics (moisture content, density, and strength) of the A. dubia pellets were investigated. During this study, it was found that the density in the dry mass (DM) of the pellets ranged from 1119.86 to 1192.44 kg m-3. The pellet moisture content ranged from 8.80 to 10.49%. After testing pellet strength, it was found that the pellets which were made from plant biomass PK-1-1 (first harvest without N fertilization) were the most resistant to compression, and they withstood 560.36 N of pressure. The dry fuel lower heating value (LHV) of the pellets was sufficiently high and was very close to that of the pine sawdust pellets; it varied from 17.46 ± 0.25 MJ kg-1 to 18.14 ± 0.28 MJ kg-1. The ash content of the burned pellets ranged from 3.62 ± 0.02% to 6.47 ± 0.09%. Emissions of harmful pollutants-CO2, CO, NOx, and unburnt hydrocarbons (CxHy)-did not exceed the maximum permissible levels. Summarizing the results for the investigated properties of the combustion and emissions of the A. dubia pellets, it can be concluded that this biofuel can be used for the production of pressed biofuel, and it is characterized by sufficiently high quality, efficient combustion, and permissible emissions to the environment.

An Optimized Method for Evaluating the Preparation of High-Quality Fuel from Various Types of Biomass through Torrefaction.

The pretreatment for torrefaction impacts the performance of biomass fuels and operational costs. Given their diversity, it is crucial to determine the optimal torrefaction conditions for different types of biomass. In this study, three typical solid biofuels, corn stover (CS), agaric fungus bran (AFB), and spent coffee grounds (SCGs), were prepared using fluidized bed torrefaction. The thermal stability of different fuels was extensively discussed and a novel comprehensive fuel index, "displacement level", was analyzed. The functional groups, pore structures, and microstructural differences between the three raw materials and the optimally torrefied biochar were thoroughly characterized. Finally, the biomass fuel consumption for household heating and water supply was calculated. The results showed that the optimal torrefaction temperatures for CS, AFB, and SCGs were 240, 280, and 280 °C, respectively, with comprehensive quality rankings of the optimal torrefied biochar of AFB (260) > SCG (252) > CS (248). Additionally, the economic costs of the optimally torrefied biochar were reduced by 7.03-19.32%. The results indicated that the displacement level is an index universally applicable to the preparation of solid fuels through biomass torrefaction. AFB is the most suitable solid fuel to be upgraded through torrefaction and has the potential to replace coal.

Solidification characteristics of solid biofuel densified by two-step torrefaction process.

Coal coke, which is used widely in industrial furnaces, emits large amounts of CO2. To utilize solid biofuels as alternatives to coal coke, the fuel ratio of the biofuels must be improved to generate functions, such as deoxidization, permeability, and carbon pickup. In this study, an innovative densification molding method is proposed; it uses a two-step torrefaction process with a high CO2 reduction effect. The molding method consists of the following two-step torrefaction process at torrefaction temperatures of 463-773 K: In the first step, raw biomass is torrefied to remove some of the volatile matter that inhibits densified molding. In the second step, the torrefied biomass is densified at the above temperature. The purpose of the second torrefaction step is to further enhance the fuel ratio due to the conversion of volatile matter to fixed carbon and to develop the thermal softening of lignin. Solid biofuel densified using a two-step torrefaction process was produced from a Japanese cedar sample, and it was found that its fuel ratio was significantly improved. Furthermore, the mechanism of the adhesive effect during carbonization was elucidated by analyzing the structure of the densified solid biofuel using Raman spectroscopy.

Conversion of Problematic Winery Waste into Valuable Substrate for Baker's Yeast Production and Solid Biofuel: A Circular Economy Approach§.

Research background: Wine production, which is considered a major sector in food industry, often involves the use of a large amount of resources. Moreover, wine making generates a large amount of grape pomace, which is generally used for low-value applications such as fertiliser and animal feed. The aim of the present research is to explore the possibility of improving the overall sustainability of traditional winemaking. Experimental approach: A zero-waste process was developed. It includes the production of white wine and the substantial valorisation of grape pomace, which is converted into solid biofuel, tartaric acid and concentrated grape extract as feedstock for industrial baker's yeast production. Results and conclusions: We estimate that a significant surplus of renewable energy of approx. 3 MJ/kg processed grapes can be obtained during this conversion. The suitability of grape extract as a potential substrate for industrial baker's yeast production was evaluated and the feasibility of a partial replacement of molasses (up to 30 %) was demonstrated. Novelty and scientific contribution: We present a circular economy approach for the conversion of winery biowaste into high-value resources such as feedstock and solid biofuel.

Effect of compacting conditions on the viscoelastic properties of banana leaf waste and briquette quality.

This study evaluated the effects of the temperature and pressure used when compacting banana leaves on viscoelastic properties and briquette quality. Banana leaves with 12.4% of humidity were milled at two ranges of average particle size. The briquetting was carried out in a cylinder-piston device coupled to a universal mechanical test machine, under different compacting temperatures (30 and 120 °C) and pressures (20, 40 and 60 MPa). Several parameters, including compacting module, porosity index, final density, critical density, compacting energy, compression ratio, higher heating value, and energy density, were investigated. The banana leaf particles smaller than 1.7 mm performed better during compaction, with low compacting resistance. Temperature showed less influence on final density than pressure. The increase of pressure contributed to decreasing the compacting module and to achieving denser briquettes. It was not necessary to apply high temperature to obtain briquettes with high final density and energy density. The optimum briquetting process parameters identified can be used to produce briquettes from banana leaves at an industrial scale with an extruder. Briquetting adds value to banana leaf waste and reduces environmental pollution.

Sustainable ecofriendly recruitment of bioethanol fermentation lignocellulosic spent waste biomass for the safe reuse and discharge of petroleum production produced water via biosorption and solid biofuel production.

Sustainable lignocellulosic spent waste rice straw (SWRS) from bioethanol production inventively applied in this study to valorize petroleum production produced water (PPPW). SWRS expressed efficient pollutant removal over a wide range of petroleum concentration, temperature, pH, salinity, and mixing rate reaching approximately 217 mg/g, within four hours contact time. Kinetic studies revealed a pseudo-second-order chemisorption process with a boundary layer control and 16.97 kJ/mol activation energy where the intra-particle diffusion was not the only rate regulatory step. Thermodynamic studies revealed spontaneous, favorable, and endothermic adsorption, with a strong affinity between the SWRS and oil molecules. Biosorption mechanism studies proved the enrollment of SWRS components' lignin, cellulose, and hemicellulose in the oil uptake with the predominance of chemisorption over physisorption onto the rough and highly porous SWRS surface. A single-stage batch biosorption process was designed based on the best fitted Langmuir adsorption isotherm and applied on a real PPPW sample. The Egyptian standard limits for safe industrial effluents discharge into marine environment with a concomitant decrease in scale formation precursors were achieved recommending its safe reuse for enhanced oil recovery. Finally, for accomplishing zero-waste, SWRS disposed of PPPW treatment substantiated valorized solid biofuel with a sufficient calorific value 38.56 MJ/kg.

Comparison of thermochemical conversion and anaerobic digestion of perennial flower-rich herbaceous wild plant species for bioenergy production.

The combustion quality of three perennial wild plant species Tanacetum vulgare L., Centaurea nigra L. and Artemisia vulgaris L. was investigated in comparison to the energy yield obtained from anaerobic digestions of these biomasses. Combustion resulted in 1.5-2.8 times higher energy yield compared to anaerobic digestion. All wild plants showed a similar higher heating value to Miscanthus × giganteus Greef et Deuter and Panicum virgatum L. (16.0-17.0 MJ kg-1). The ash-melting behavior of all wild plants was like Sida hermaphrodita L. Rusby, since the ash did not sinter at 1200 °C. However, Artemisia vulgaris L. had highest ash content (5.2-5.7% of dry matter) with a low ash melting behavior (1000 °C) attributed to a high potassium content and calculated phase composition. Therefore, careful consideration should be given to select the wild plants to meet the requirements for their use as solid biofuels in residential and commercial applications.

Oxidative torrefaction performance of microalga Nannochloropsis Oceanica towards an upgraded microalgal solid biofuel.

Microalgae are a promising feedstock for carbon-neutral biofuel production due to their superior cellular composition. Alternatively, oxidative torrefaction has been recognized as a potential thermochemical technique for microalgal solid biofuel upgrading. Herein, by using microalga N. oceanica as a feedstock, several characterizations are adopted for evaluating the potential of oxidative torrefaction towards microalgal solid biofuel production. The oxidatively torrefied microalgae can be upgraded as lignite. After in-depth analysis, significant change in the surface microstructure of oxidatively torrefied microalgae is largely changed (via wrinkle and fragmentation) The hydrophobicity, thermal decomposition, thermal stability, and aromatization of oxidatively torrefied microalgae can be largely enhanced as the oxidative torrefaction severity increase. With the increasing torrefaction temperature, the hydrophobicity of oxidative torrefied microalgae gradually improved. The decomposition of C-2/3/5, and -OCH3, the CO bonds of CH3CO-, and the aromatization occurs via oxidative torrefaction according to the NMR analysis. For XPS analysis, torrefaction operation significantly decreases the carbide carbon and enhances the graphitization. As a result, the thermal stability of oxidatively torrefied microalgae is improved. Conclusively, the information obtained in this study can provide insights into the evaluation of oxidative torrefaction performance and fuel properties of microalgal solid biofuel, which may help accelerate the advancement of oxidative torrefaction industrialization.

Impacts of Global Solid Biofuel Stove Emissions on Ambient Air Quality and Human Health.

Global solid biofuel stove emissions strongly impact air quality, climate change, and human health. However, investigations of the impacts of global solid biofuel stove emissions on human health associated with PM2.5 (particulate matter with aerodynamic diameter ≤2.5 µm) and ozone (O3) are limited. Here, we quantify the impacts of global solid biofuel stove emissions on ambient PM2.5 and O3 air quality and the associated human health effects for the year 2010, using the Community Atmosphere Model coupled with Chemistry version 5.3. Annual mean surface PM2.5 concentrations from global solid biofuel stove emissions averaged over 2006-2010 are up to 23.1 µg m-3, with large impacts found over China, India, sub-Saharan Africa, and eastern and central Europe. For surface O3 impacts, we find that global solid biofuel stove emissions lead to increases in surface O3 concentrations by up to 5.7 ppbv for China, India, and sub-Saharan Africa, and negligible impacts or reductions of up to 0.5 ppbv for the US, Europe, and parts of South America. Global solid biofuel stove emissions for the year 2010 contribute to 382,000 [95% confidence interval (95CI): 349,000-409,000] annual premature deaths associated with PM2.5 and O3 exposure, with the corresponding years of life lost as 8.10 million years (95CI: 7.38-8.70 million years). Our study highlights air quality and human health benefits of mitigating emissions from the global solid biofuel stove sector, especially over populous regions of low-income and middle-income countries, through promoting clean household energy programs for the residential energy supply.

A life cycle assessment of energy recovery using briquette from wastewater grown microalgae biomass.

Microalgae biomass (MB) is a promising source of renewable energy, especially when the cultivation is associated with wastewater treatment. However, microalgae wastewater technologies still have much to improve. Additionally, microalgae biomass valorization routes need to be optimized to be a sustainable and feasible source of green bioenergy. Thus, this paper aimed to evaluate the environmental impacts of the production of briquettes from MB, cultivated during domestic wastewater treatment. Also, it was evaluated how much the drying of the MB affected the life cycle and the environment. Improvements in the life cycle to mitigate the environmental impacts of this energy route were proposed. Cradle-to-gate modeling was applied to obtain a life cycle assessment (LCA) from cultivation to the valorization of MB, through its transformation into a solid biofuel. With LCA, it was possible to identify which technical aspect of the process needs to be optimized so that environmental sustainability can be achieved. Two scenarios were compared, one with the microalgae growth in a high-rate algal pond (HRAP) (scenario 1) and the other in a hybrid reactor, formed by a HRAP and a biofilm reactor (BR) (scenario 2). LCA highlighted the electric power mix, representing, on average, 60% of the total environmental impacts in both scenarios. The valorization of MB in briquettes needs to consume less energy to offset its yield. The environment suffered pressure in freshwater eutrophication, due to the release of 3.1E-05 and 3.9E-05 kg of phosphorus equivalent; in fossil resources scarcity, with the extraction of 1.4E-02 and 4.5E-02 kg of oil equivalent; and in climate change, by the emission of 1.0E-01 and 1.9E-01 kg of carbon dioxide (CO2) equivalent, in scenarios 1 and 2, respectively. Scenario 1 was highly damaging to terrestrial ecotoxicity, with the release of 3.5E-01 kg of 1,4 Dichlorobenzene, coming from the CO2 used in MB growth. This category was the one that most negatively pressured the environment, differing from scenario 2, in which this input was not required. This was the only impact category in which scenario 2 had a better environmental performance when compared to scenario 1. Cotton, required in scenario 2, represented up to 87% of emissions in some of the evaluated categories. Despite the impacts that occurred in the two modeled scenarios, the environmental gains due to the use of wastewater for microalgae growth, replacing the synthetic cultivation medium, stood out. In the sensitivity analysis, two alternative scenarios were proposed: (i) electricity consumption for drying has been reduced, due to the natural decrease of MB humidity, and (ii) MB briquettes were considered a substitute for coal briquettes. Results indicated that pressures on climate change and fossil resource scarcity were eliminated in both scenarios and this also occurred for freshwater eutrophication in scenario 2. This paper contributes to the improvement and development of converting MB routes into more sustainable products, causing less pressure on the environment. Also, the study contributes to filling a gap in the literature, discussing methods and technologies to be improved, and consequently making microalgae biotechnology environmentally feasible and a potential renewable energy alternative.

Biowaste hydrothermal carbonization for hydrochar valorization: Skeleton structure, conversion pathways and clean biofuel applications.

Hydrothermal carbonization (HTC), as one of thermal conversion techniques, shows promising commercial potential for hydrochar production from wet biowaste. This technique was re-discovered and regraded as artificial coalification to mimic natural process. In recent years, researchers concern more about hydrochar obtained from HTC, since large amount of organic waste including sludge, algae, food waste, manure etc. are generated with high moisture, which can be directly used as reaction medium, and hydrochar has high carbon density and energy retention. With this regard, application of hydrochar as biofuel is a renewable and sustainable way for biowaste recycling. In this review, HTC process and pathways about hydrochar formation from (N-free/N-rich biowaste), carbon-skeleton structure, critical elements on clean properties, and hydrochar pelletization for biofuel production were presented. Potential applications and challenges for HTC as green and sustainable way were presented, which will provide prospect for hydrochar as clean and renewable biofuel.

Simultaneous implementation of sludge dewatering and solid biofuel production by microwave torrefaction.

Sludge dewatering is a matter of great concern to reduce the volume of sludge, stabilize its organic components, and achieve resource utilization. This study investigates sludge dewatering by microwave torrefaction along with the production of sludge solid biofuel at 480-800 W combined with durations of 5-25 min. Proximate analysis, calorific value analysis, thermogravimetric analysis, and scanning electron microscopy observations are employed to evaluate the dewatering degree, fuel properties, and energy efficiency of the torrefaction process. The independent parallel reaction (IPR) model and particle swarm optimization (PSO) analysis are also adopted for sludge pyrolysis kinetics calculation. The results show that microwave torrefaction is efficient for sludge dewatering with a short duration. The produced sludge solid biofuel is similar to stone-like coal, and can be used for civil or industrial boilers after flotation or just co-firing with briquette. The ash content of sludge solid biofuel shows a declining trend and the surface characteristics change from smooth to rough and fluffy with increasing the torrefaction severity. The bio-oil is mainly composed of phenols, siloxanes, and cholesterol. In addition, hydrogen is detected in the torgas. Furthermore, it is found that lower torrefaction power with a shorter duration yields a higher energy efficiency of the torrefaction process.

Influence of process parameters on hydrothermal modification of soybean residue: Insight into the nutrient, solid biofuel, and thermal properties of hydrochars.

Soybean (SB) solid residue after oil extraction was investigated in a hydrothermal modification process to provide an eco-friendly solution to SB solid waste disposal for an actual environmental management effort. SB hydrochars (HCs) were derived either by conventional heating hydrothermal treatment (HTT) under intense conditions (200, 250, and 300 °C for 2 h) or by microwave-assisted hydrothermal treatment (MHTT) under mild conditions (160, 190, and 220 °C for 1 h). Physicochemical properties of SB HCs and the transformation of nitrogen (N) and phosphorus (P) functionalities during HTT and MHTT were characterized using several tools. Ultimate and XPS analyses elucidated N transformation, e.g., 5.51 wt % N of raw SB residue decreased to 3.48 and 3.51 wt % after HTT and MHTT, respectively. The P bioavailability of raw SB (3.46 mg/g) was improved after HTT (26.7 mg/g) and MHTT (10.9 mg/g), depicting the practical application of HCs for soil amendment. Atomic H/C and O/C ratios of SB HCs decreased as treatment temperature increased. HCs showed credible higher heating value (HHV; 22.3-25.5 MJ/kg for HTT and 20.5-22.1 MJ/kg for MHTT), higher than various low-rank coals. Besides, energy densification and fuel ratio improved in intense conditions. The thermogravimetric analysis showed HCs possessed better thermal stability. The improved performance of SB HCs indicated that HTT and MHTT provided a green environmental route of SB waste management, valorization, and utilization.

Pelletizing of lignocellulosic wastes as an environmentally friendly solution for the energy supply: insights on the properties of pellets from Brazilian biomasses.

In the context of the circular bioeconomy and cleaner production, the incorporation of the by-products of plant biomass production in the bioenergy chain is fundamental. However, lignocellulosic wastes have properties that hinder their use for the production of biofuels. This study aims to evaluate how blends of lignocellulosic wastes improve the physical, chemical, and mechanical quality of pellets destined to the industrial sector, and to identify the challenges associated with the use of agroforestry biomass as raw material for pelletizing. Pellets were produced from blends of soybean wastes, sorghum wastes, pine needles, rice powder, Eucalyptus sawdust, and charcoal fines. Additionally, pure pellets composed of soybean wastes, sugarcane bagasse, and pine wood were evaluated. The effect of biomass type on the energy density, ash content, net heating value, and ultimate analysis was significant. The pellets produced with soybean wastes presented high contents of N (3.5-4.9%) and ashes (16.4-26.7%), besides low mechanical durability (≤ 96%), hindering its commercialization for industrial purposes. Pellets with sugarcane bagasse presented N (1.5%), S (0.03%), ashes (5.6%), mechanical durability (96.6%), and net heating value (15.1 MJ kg-1), suitable for industrial energy use in accordance with ISO 17225-6. The high N and ash contents and the low mechanical durability are the greatest challenges for the energy use of pellets produced from Brazilian agroforestry wastes.

Landfill leachate as an alternative moisture source for hydrothermal carbonization of municipal solid wastes to solid biofuels.

Hydrothermal carbonization (HTC) of yard waste (YW) and food waste (FW) was performed in landfill leachate (LL) to overcome the unnecessary exploitation of our limited natural resources. The physicochemical properties and combustion behavior of the resulting hydrochars were compared with those obtained using distilled water (DW) as reaction medium. Although performing HTC in LL led to lower hydrochar mass yields (43% YWH and 36% FWH) than DW (47.1% YWH and 41.5% FWH), it had minimal impact on the fuel characteristics of the hydrochars. Notably, the higher heating value of the hydrochars prepared in LL (22.8 MJ kg-1 for YWH and 30.2 MJ kg-1 for FWH) is comparable to that of conventional solid fuels, and may, therefore, be considered as inexpensive alternatives to fossil fuels. Overall, the results of this study conclusively suggest that the use of LL as an alternative moisture source can significantly improve the sustainability of HTC technology.

Hydrochar production from defective coffee beans by hydrothermal carbonization.

This study aimed to produce and characterize hydrochars from defective coffee beans and its application as a solid fuel. Defective coffee beans were used as precursor residue for hydrochar synthesis. Reactions were run in a high-pressure reactor at temperatures of 150, 200 and 250 °C, under autogenesis pressure, for 40 min. Solid phase was recovered by filtration and characterized by CHNO-S analyzer, thermogravimetric analysis and differential scanning calorimetry. Hydrothermal carbonization temperature was key to change energy values and fuel properties. These results suggest hydrothermal carbonization is an effective and simple strategy for converting coffee waste into functional, high-quality, and energy-dense solid biofuels.

Personal exposure to VOCs (BTX) and women health risk assessment in rural kitchen from solid biofuel burning during cooking in West Bengal, India.

In this study, personal exposure to benzene, toluene and xylene as important VOC species of incomplete combustion are assessed, considering the ventilation condition of the rural kitchens throughout the seasons. Annual mean total BTX levels were 148.51, 76.98, 34.91 and 13.34 µgm-3 for the rural kitchens with openness of <25%, 25-50%, 50-75% and >75% respectively. Overall annual mean concentration of benzene, toluene and xylene level was found to be 52.35, 8.85 and 7.23 µgm-3 respectively. Annual mean total BTX was found across the openness of the kitchens to be 68.43 µgm-3. There was no significant interaction between the independent variables 'openness' and 'season' explaining pollution exposure variability. Openness of the kitchens was the only significant predictor for BTX exposure concentration variation. Average daily dose (ADD) analysis showed median value of 1.439 × 10-3 mg/kg-day with 95% certainty range from 9.04 × 10-4 mg/kg-day to 2.220 × 10-3 mg/kg-day. Hazard index (HI) indicates no significant risk of non-carcinogenic effect from the exposure to benzene, toluene and xylene. In ADD and all non-cancerous risk estimates (HQ of benzene, toluene, xylene), exposure time emerges as the single most contributor whereas, annual average pollutant exposure is the second most risk contributor in all the cases. Lifetime cancer risk of benzene exceeded the acceptable level indicating probable cancer risk and inhalation unit risk alone contributes above 75%; exposure time came after with 16.3% contribution.

Valorization of palm biomass wastes for biodiesel feedstock and clean solid biofuel through non-sterile repeated solid-state fermentation.

Palm biomass wastes are currently considered as promising solid biofuels. However, their high potassium content leads to formation of slag in combustion chambers and causes frequent power-plant shutdowns for maintenance. Therefore, this study aimed to develop a low-cost practical biological pretreatment for these wastes. Oleaginous fungi Aspergillus tubingensis TSIP9, which originates from palm wastes, was used to pretreat biomass wastes and simultaneously produce oils through non-sterile solid state fermentation (SoSF). The operating conditions were optimized through response surface methodology. The fungi could grow and produce oils with good biodiesel fuel properties. After SoSF, potassium content in biomass wastes was reduced by 90% and cellulose content increased to >57%, making it suitable as clean solid biofuel. Repeated-SoSF with 90% substrate replacement was highly effective in continuously pretreating biomass wastes and producing fungal oils. This study demonstrates the cost-effective and environmentally friendly process for production of clean renewable energy through zero-waste strategy.

Comparative production of biochars from corn stalk and cow manure.

The aim of the present work was to compare corn stalk (CS) and cow manure (CM) for hydrochar production at different reaction temperatures (180-260 °C) and retention times (1-4 h). CM and CS resulted in hydrochars with significantly different physicochemical properties; however, both led to similar yields (30-65%). CM-derived hydrochar had a lower carbon content but a higher nitrogen and ash content than CS-derived hydrochar. CM-derived hydrochar demonstrated potential as a soil amendment due to its higher content of nitrogen, the presence of surface functional groups and higher specific surface area in comparison to CS-derived hydrochar. In comparison, CS-derived hydrochar demonstrated suitability as a solid fuel due to its high heating value and low ignition temperature. This study revealed that the composition of lignocellulose significantly impacted the properties and thus potential applications of hydrochar.