Study On Biomass Chemical Looping Gasification Of Fe/Cu Based Oxygen Carrier Modified By TiO₂ And K₂CO₃

With the increasing shortage of fossil fuels and the deterioration of human living environment,people pay more attention to new energy.Bioenergy is a new kind of energy that can solve this dilemma.Biomass gasification is one of the conventional ways to use biomass energy.At present,the traditional gasification method has the disadvantage of high gasification cost.Biomass chemical looping gasification can reduce the cost of gasification,at the same time,chemical looping gasification can effectively control the CO and H₂ ratio in syngas,improve the quality of syngas.Therefore,based on Fe/Cu-based oxygen carrier,this paper conducts thermodynamic simulation of the gasification process,modifies the oxygen carrier with inert carrier TiO₂ and alkali metal,studies the chemical looping gasification of pine sawdust,and looks for the best reaction condition of gasification.Based on Fe/Cu-based oxygen carrier and Gibbs free energy minimization principle,the thermodynamic analysis of biomass chemical looping gasification with HSC Chemistry was carried out in this paper.The partial oxidation of biomass can be promoted and the quality of syngas can be improved by increasing the peroxide coefficient and steam biomass ratio S/B.Fe/Cu oxygen carriers modified by inert carrier TiO₂?Fe:Cu=1:2?were prepared by mechanical mixing method to investigate the cyclic reaction performance of oxygen carriers under high temperature conditions.The biomass chemical looping gasification experiment was carried out in a fixed bed reactor.The experimental results showed that:the oxygen release performance of TiO₂-modified Fe/Cu oxygen carrier decreased,but the oxygen carrying performance remained good.The characterization results show that the addition of inert carrier can increase the dispersion and specific surface area of the oxygen carrier and improve the anti-sintering performance of the oxygen carrier.However,with the increase of cycle times,the surface of oxygen carrier is obviously sintered.Removing the alkali metal in pine wood chips using acetic acid solution,at the same time,carrying oxygen of Cu/Fe/Ti was modified by biomass ash and K₂CO₃respectively,the results of biomass chemical looping on the fixed bed gasification experiment shows that the alkali metal will not only improve the body reaction activation energy of carrying oxygen,increase the number of body surface to the active site of oxygen carryer,make it easier for gasification reaction,also can promote the H₂content in gasification components and calorific value of the syngas.Finally,Fe/Cu/Ti/K oxygen carrier was used to react with the pine sawdust in the fixed bed for finding the best reaction conditions.The experiment's results show that the best reaction condition is when the temperature was 850?,peroxic coefficient was 0.2,S/B was 1.In this reaction condition,heating value,gas rate and carbon conversion rate is best.At the same time,the chemical looping gasification of different kinds of biomass was carried out in the fixed bed to explore the gasification characteristics of different kinds of biomass.The results show that chemical looping gasification is a suitable method for different kinds of biomass...