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Gasification of the char obtained from the spent substrate after mushroom cultivation was carried out in a thermobalance connected to a mass spectrometer in the temperature range from 200 to 950 °C and CO2 concentration from 5 to 100 vol%. Under non-isothermal conditions, in addition to the char gasification process, both carbonation and calcination reactions occurred. The investigation of gasification kinetics in CO2 was carried out under isothermal conditions. The rate of gasification reaction was determined from the shrinking core model, and kinetic constant has been calculated from Langmuir–Hinshelwood kinetics. On the basis of the conducted research, it was observed that the saturation of active sites on the char particles occurred above 50 vol% CO2, regardless of temperature. The analysis of gas composition indicates CO as the main product of gasification. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the process of biodrying of municipal solid waste from the old landfill to preparing it for pyrolysis or gasification. New aspect of this research is biodrying of waste from old landfill. Biodrying of wastes was carried out at different aeration rates (7, 35, and 175 dm3/kg dry matter/d) at two temperatures (23 and 50 °C). The research was carried out in the laboratory bioreactors of special design (lysimeters), which simulated the conditions prevailing in the landfill. The optimal conditions for reduction of moisture in waste (63.2%) has been attained for the highest aeration rate (175 dm3/kg dry matter/d) and temperature equal to 50 °C. The final moisture content of the obtained biodried product was 23% w/w. In the bioreactor, in which the greatest reduction of moisture was obtained, the total amount of produced CO2 was 44.9 gC/kg dry matter, and the biodrying efficiency was equal to 0.89. During biodrying of wastes in optimal conditions, higher heating value of waste increased from 4.3 to 11.0 MJ/kg. As a result of the performed pyrolysis of biodried waste at 900 °C, char, oil, and gas were obtained the respective yields of 47, 32, and 21% w/w. The gas emerging in the gasification process was characterized by higher heating value equal to 11.3 MJ/m3. [ABSTRACT FROM AUTHOR]

Abstract Steam gasification of char derived from spent mushroom substrate was carried out in thermobalance coupled with mass spectrometer, in the temperature range of 800–900 °C and the steam concentration from 10 to 50 vol%. Syngas production was influenced by temperature and steam concentration. The highest yield of H 2 production (42.9 mol H 2 /kg) was achieved at temperature of 800 °C and steam concentration of 50 vol%. The composition of the generated gas was strongly influenced by the water-gas shift reaction. The grain model was used to describe the kinetics of gasification of the char and the calculated activation energy was equal to 99.0 kJ/mol. The low activation energy of the gasification process was caused by a high content of mineral compounds in the char. The obtained results indicate the potential for gasification of the spent mushroom substrate and found to be an initial and important stage in the development of the gasification process in mushroom production plants. Highlights • Spent mushroom substrate showed high potential for utilization by steam gasification. • The highest yield of H 2 was attained at 800 °C and steam concentration of 50 vol%. • Grain model appeared to be the most suitable to describe the kinetics of gasification. • Low activation energy (99.0 kJ/mol) was caused by high content of minerals. [ABSTRACT FROM AUTHOR]

This study aimed at determination of the char, tar and gas production yield during pyrolysis of the spent mushroom substrate left after cultivation, as well as its individual components, namely the casing layer and the mushroom substrate. The pyrolysis process was carried out in a thermobalance combined with a mass spectrometer. Based on the analysis of mass losses, it was found that the largest amount of flammable gases and tar were released during pyrolysis of the spent mushroom substrate. The yield of char, tar and gas during pyrolysis at 600 °C were respectively equal to 57.1, 14.4 and 14.5 wt.%. The loss of mass at temperature above 600 °C was associated with thermal decomposition of calcium carbonate, calcium sulfate, and oxidation of the char. The deconvolution of DTG curves and volatile products such as H 2 , CH 4 , CO, CO 2 , H 2 O and tar allowed to determine the decomposition of the compounds contained in the spent mushroom substrate during the pyrolysis process. The kinetic parameters were calculated from the isoconversional model for thermal degradation of biomass. The results could aid in managing organic wastes including the energy production. [ABSTRACT FROM AUTHOR]

The study evaluated possibilities of using sorghum biomass as a substrate for production of methane in agricultural biogas plants. Five different sorghum varieties, cultivated at two different localisations: Straszków and Śmiłów were analysed. The analysis of biochemical methane potential (BMP) indicated that in both localisations the best results were achieved in the case of Sucrosorgo variety of sorghum. Yield of methane from hectare was 8586 m3 ha-1 year-1 in location Straszków, and 7859 m3 ha-1 year-1 in location Śmiłów. The lowest yield from hectare and the lowest efficiency of methane from hectare in both locations were registered for the Akklimat variety (2320 m3 ha-1 year-1) and Nutri Honey (2762 m3 ha-1 year-1). The comparative analysis of the ERoEI index proved that the Sucrosorgo variety is definitely the most effective (8.71 at the Straszków location and 7.97 at the Śmiłów location) from the others in terms of energy efficiency. The energy efficiency of this variety is nearly four times higher than the least effective (Akklimat - 2.34). [ABSTRACT FROM AUTHOR]

In this study the municipal solid waste degradation processes in simulated landfill bioreactors under aerobic and anaerobic conditions is investigated. The effect of waste aeration on the dynamics of the aerobic degradation processes in lysimeters as well as during anaerobic processes after completion of aeration is presented. The results are compared with the anaerobic degradation process to determine the stabilization stage of waste in both experimental modes. The experiments in aerobic lysimeters were carried out at small aeration rate (4.41 ⋅ 10 −3 l min −1 kg −1 ) and for two recirculation rates (24.9 and 1.58 l m −3 d −1 ). The change of leachate and formed gases composition showed that the application of even a small aeration rate favored the degradation of organic matter. The amount of CO 2 and CH 4 released from anaerobic lysimeter was about 5 times lower than that from the aerobic lysimeters. Better stabilization of the waste was obtained in the aerobic lysimeter with small recirculation, from which the amount of CO 2 produced was larger by about 19% in comparison with that from the aerobic lysimeter with large leachate recirculation. [ABSTRACT FROM AUTHOR]

The effect of air flow rate on the change of biomass (organic waste material) temperature and moisture content during an autothermal drying process is discussed. The laboratory-scale experiments were performed using a 240-dm3 horizontal composting reactor equipped with an air supply system, biomass temperature measuring system, and air humidity and temperature sensors. An organic fraction of municipal solid waste with the addition of a structural material was used as a substrate in this process. As a result of the autothermal biodrying process, the initial moisture content of organic waste ranging from 0.8 to 0.9 kgH2O/kg of raw waste mass decreased by 50%. Water balances were calculated before and after biodrying, and the difference was less than 10%. The heat of combustion and the calorific value of dried wastes ranged respectively from 6,750 to 12,280 kJ/kg and from 8,050 to 10,980 kJ/kg. The biodrying efficiency varied from 0.73 to 0.97, depending on process conditions. Energy balances showed that average biological energy production rates varied between 1.66 and 6.90 W/kg of raw waste mass. [ABSTRACT FROM AUTHOR]

The process of pyrolysis of beet pulp, a by-product after the extraction of raw sugar from sugar beet, with the addition of defecation lime was studied in a thermobalance coupled with a mass spectrometer. The beet pulp pyrolysis process took place completely at 600 °C, and the resulting char, tar and gas were characterized by higher heating values of 23.9, 21.6 and 7.77 MJ/kg, respectively. The addition of the defecation lime to beet pulp caused both an increase in the char production yield and a decrease in the tar production yield. At the same time, the higher heating value of char and tar decreased along with the increase of defecation lime added to the sample. The deconvolution of derivative thermogravimetric (DTG) curves allowed us to identify the basic components of beet pulp, for which the activation energy by isoconversion method was calculated. The 20 wt.% addition of defecation lime caused an increase of the activation energy by about 18%. Further increase in the defecation lime content resulted in a reduction of activation energy. At the temperature above 600 °C, calcination of calcium carbonate contained in defecation lime occurred. The CO2 produced during calcination process did not cause auto-gasification of char. [ABSTRACT FROM AUTHOR]

The research carried out in this work determined the biochemical methane potential of the solid fraction remaining after acid fermentation with the recovery of volatile fatty acids and hydrogen, in which kitchen waste was used as the substrate. The methane fermentation process was carried out in bath bioreactors without pH regulation during the process, with the addition of digestate sludge from wastewater treatment plants and without its addition, at various substrate concentrations. It was found that the solid fraction after acid fermentation with the addition of digested sludge, is a good substrate for biogas production. The highest biochemical methane potential of 640 cm3 CH4×gsmo-1 was found in the process in which the waste solid fraction after acid fermentation concentration was 100 gm×dm-3. [ABSTRACT FROM AUTHOR]

Dark fermentation of kitchen wastes was studied in batch bioreactors, with no pH adjustment, to evaluate the effect of the initial organic load on the process performance in terms of volatile fatty acids and H 2 production. Initial organic load of the kitchen wastes ranged from 4.1 to 48.2 gVS/L. Acetic and butyric acids were produced in the largest amount. At the initial organic load of 48.2 KW gVS/L the highest concentration of volatile fatty acids was 9.81 g/L. The maximum production yield of H 2 (76.1 mL/gVS) was found for the initial organic load of kitchen wastes at 14.3 gVS/L. The carbon balance calculation showed that the maximum CO 2 yield of 0.34 gC/gC was attained in the bioreactor with the initial organic load of 14.3 gVS/L. The microbiological analysis revealed that the predominant microorganisms in the dark fermentation process were Bacteroidetes , Firmicutes, Spirochaetes and WWE1 at phyla level. [ABSTRACT FROM AUTHOR]

Abstract: Biomass from Miscanthus giganteus, Sida hermaphrodita and Sorghum Moensch was treated with Fenton’s reagent for 2 hours under optimal conditions (pH=3, mass ratio of [Fe2+]:[H2O2] equals 1:25 for Miscanthus and Sorghum and 1:15 for Sida). The degrees of delignification were 30.3%, 62.3% and 48.1% for the three plant species, respectively. The volatile fatty acids concentration after chemical pretreatment was high enough for production of biogas with a high methane content. Combined chemical oxidation and enzymatic hydrolysis with cellulase and cellobiase led to glucose contents of above 4g/L. Among the tested plants, the highest biogas production (25.2Ndm3/kg TS fed) with a 75% methane content was obtained with Sorghum Moensch. The results of the three-step process of biomass degradation show the necessity of applying a chemical pretreatment such as oxidation with Fenton’s reagent. Moreover, the coagulation of residual Fe3+ ions is not required for high biogas production. [Copyright &y& Elsevier]

The aim of the study was to evaluate the possibility of using the process of dark fermentation to convert kitchen waste into valuable volatile fatty acids in a semi-continuous process at different values of the organic loading rate (2.5 and 5.0 gVS/(L × d)) and hydraulic retention time (5 and 10 d) using anaerobic mixed microbial consortia. The experiments were performed in a bioreactor of working volume 8L with pH control. The maximum volatile fatty acids yield in a steady state (22.3 g/L) was achieved at the organic loading rate of 5.0 gVS/(L × d) and HRT of 10 days. The main products of dark fermentation were acetic and butyric acids, constituting, respectively, 35.2–47.7% and 24.1–30.0% of all identified volatile fatty acids. Additionally, at the beginning of the fermentation and in a steady-state condition, the microbial population analysis (16S rDNA) of the fermentation mixture with the most effective volatile fatty acids generation has been performed to monitor the DF microflora development. The dominant microorganisms at a phylum level in a steady state were Firmicutes (44.9%) and Bacteroidetes (30.1%), which indicate the main role of those phyla in the volatile fatty acids synthesis. [ABSTRACT FROM AUTHOR]