In this study energy recovery of digestate from a biogas plant was investigated via air gasification. gasification tests were executed in a pilot scale rotary kiln plant having a nominal biomass feeding rate of about 20 kg/h. The equivalence ratio was varied from 0. 22 to 0. 39 with the goal to approach the autothermal condition. Tests were carried out for 5 h in steady state condition. Syngas composition, char and gas yields were measured. To improve the cold gas efficiency of the process, a mixture of digestate and almond shells (60: 40 wt%) was gasified. Autothermal condition was reached with the mixture using equivalence ratio of 0. 30 where the corresponding cold gas efficiency achieved the maximum value of 55%. The raw gas had a lower heating value of 4– 5 MJ/Nm3. To evaluate possible improvements in the produced gas properties, in this work the effect of steam injection was also investigated.

Integrated gasification Combined Cycle power plants generate electricity by utilizing the syngas obtained from the carbonaceous materials via gasification. These systems commonly use coal fuel, however, biomass fuels like bagasse could be a more environmentally friendly option. This study was aimed at analyzing the effects of varying operating parameters (such as temperature, pressure, O2/fuel, and water/fuel ratios), and fuel feedstocks (i. e., coal, bagasse, and coal-bagasse co-firing) on the syngas composition. Based on the data obtained from a commercial power plant, an equilibrium model was developed and validated using the Aspen Plus® software. Sensitivity analysis was carried out by varying the considered operating parameters and selected fuel feedstocks. The results of this study have manifested that low temperatures, low O2/fuel ratio, and high water/fuel ratio produce syngas with a comparatively higher H2/CO ratio. The highest H2/CO ratios of 1. 16, 0. 99, and 0. 84, were obtained for bagasse, co-firing, and coal, respectively at operating parameters of 1200°C temperature, 0. 5 O2/fuel, and 0. 6 water/fuel ratios. Furthermore, bagasse and co-firing of coal-bagasse feedstocks could provide a better quality of syngas as compared to that of coal feedstock. The results of this study would also help to operate the Integrated gasification Combined Cycle plants at optimum performance by utilizing different fuels and by appropriately adjusting the operating parameters.

Improved alkali resistant refractoriness are needed for biomass and black liquor gasification (BBLG). One particularly harsh application is linings for gasifiers used in the treatment of black liquor (BL). Black liquor is a water solution of the non-cellulose portion of the wood (mainly lignin) and the spent pulping chemicals (Na2CO3, K2C O3, and Na2S). Development of new refractory materials for the black liquor gasification (BLG) application is a critical issue for implementation of this technology. FactSage@ thermodynamic software was used to analyze the phases present in BL smelt and to predict the interaction of BL smelt with different refractory compounds. The modeling included prediction of the phases formed under the operating conditions of high temperature black liquor gasification (BLG) process. At the operating temperature of the BLG, Fact Sage@predicted that the water would evaporate from the BL and that the organic portion of BL would combust, leaving black liquor smelt composed of sodium carbonate (70-75%), potassium carbonate (2-5%), and sodium sulfide (20-25%). Exposure of aluminosilicates to this smelt leads to significant corrosion due to formation of expansive phases with subsequent cracking and spalling. Oxides (ZrO2, Ce O2, La2O2, Y2 O2, Li2O, MgO and CaO) were determined to be resistant to black liquor smelt but non-oxides (SiC and Si3N4) would oxidize and dissolve in the smelt. The other candidates such as MgAl2 O2 and BaAl2 O4 were resistant to sodium carbonate but not to potassium carbonate. LiAlO2 was stable with both sodium carbonate and potassium carbonate. Candidate materials selected on the basis of the thermodynamic calculations are being tested by sessile drop test for corrosion resistance to molten black liquor smelt. Sessile drop testing has confirmed the thermodynamic predictions for Al2O3, CeO2, MgO and CaO. Sessile drop testing showed that the thermodynamic predictions were incorrect for Zr O2.

This paper investigated the possibilities of using birch wood chips for fixed-bed downdraft gasification. The preliminary air gasification resulted producer gas with an average composition of 11.5% CO, 5.4% CO2, 5.9% H2, 0.38% CH4 corresponding to a mean lower heating value of about 2 MJ/kg. The approximate size of woodchips used for gasification was around 11.5 mm for a maximum solid throughput of 0.65 kg/h. The obtained equivalence ratio (ratio between actual air fuel ratio and stoichometric air fuel ratio) as a result of air and biomass feed was close to 0.45 which was stable throughout the test. Producer gas left the gasifier at ca. 150oC and was diverted for flaring owing to the level of low energy content. Despite availability, the option for gas to generate heat and electricity via integrated gas engine has not been utilized in the present case and remained for further ongoing research.

In recent years, considering the global warming and climate changes mainly resulting from greenhouse gas emissions, especially carbon dioxide, absorption and storage of carbon dioxide in generating clean and sustainable fuels such as hydrogen fuel production have been heavily studied and investigated. Researchers have presented various methods for carbon dioxide absorption in the hydrogen production process. The biomass gasification process, alongside absorption, can enhance the generation of hydrogen-rich gas by absorbing carbon dioxide. In this study, the first hydrogen generation in the biomass gasification process has been examined, followed by the technologies available for the absorption of carbon dioxide. This study reveals that developing novel materials for absorbing and separating carbon dioxide is essential. Given their unique physicochemical and structural features, metal-organic frameworks, including pore size, high thermal stability, high absorption capacity, and pore size tuning, are helpful adsorbents for absorbing carbon dioxide and achieving clean hydrogen energy. Thus, metal-organic frameworks (MOFs) may efficiently generate high-purity hydrogen by merging biomass gasification with CO2 adsorption.