Synergistic Characterization Of Cotton Stalk And High-ash Coal In Co-pyrolysis/gasification On Gas Production

The co-pyrolysis/gasification technology of biomass and coal has attracted wide attention as a technology that bridges traditional fossil energy fuels and renewable energy fuels to produce high-quality gas or syngas.In a self-made fixed-bed reactor,the co-pyrolysis/co-gasification experiment was carried out using cotton stalks and high-ash coal as raw materials.The straw and high-ash coal were leached step by step using a leaching treatment method.The effects of different pyrolysis/gasification temperatures and biomass blending ratios on gas production and gas production components were studied.and the co-gasification gas production results were quantitatively analyzed based on the synergy coefficient.Based on the appropriate blending ratio selected,the leached straw and high-ash coal were used for cross-combination analysis.The influence of leaching method on co-gasification was evaluated by gas production and synergy coefficient.The specific results are as follows:1)Based on the principle of baffles,a raw material loading quartz boat was designed.The plate with the middle hole prevented the gas volatiles from quickly escaping,and the trapped volatiles continued to react with the fuel in the lower reaction chamber.Under the action of the internal alkali metals and alkaline earth metals of biomass and coal,the contact area between pyrolysis gas and charcoal was increased,and the degree of gas-solid reaction was deepened.Compared with the weighted sum of ordinary quartz boats,the H2 and CO output of the new type of quartz loaded boats through co-pyrolysis at high temperatures has been increased.2)When the reaction temperature is 750?1050?,the gas production of cotton stalk was the highest at 950?,which was 627.5 mL·g-1,and the coal was basically stable at 114?146 mL·g-1;in the co-pyrolysis process at 950?,cotton stalk accounts for at 20%,40%,and 60%in the mixture,there is no synergistic effect in terms of gas production.When the mixing ratio of CS was 80%,there was a sudden increase in the gas yield showing the peak value,and it can be inferred based on the proportion of gas components.The H2 is produced by the thermal decomposition of coal tar.3)In the process of co-gasification of cotton stalk and coal at 950?,when the proportion of straw is 20%,the synergy coefficient is the highest,which is 1.2525,which means that the straw acts as a catalyst to promote the conversion of coal tar into H2;When the mixing ratio of CS was 80%,the gas production was the highest,which was 1233 mL·g-1.4)Co-gasification of leached CS and leached HAC were carried out using a cross-combination method,and the gasification gas production was higher than the original gas production.The highest gas production of water leaching straw is 1416.67 mL·g-1.The coal produced by ammonium acetate leaching has the highest gas yield,and the co-gasification coefficient of co-gasification of the original coal and straw was the highest.5)Use FTIR technology to characterize the char structure of the co-gasification of CS and HAC.Studies had shown that as the proportion of CS increased.CS would provide a large amount of free radicals such as-H,-OH and-CH-during the gasification process.These small molecular free radicals could quickly combine with low-rank coals,resulting in high ash content and C=C accelerates cracking.