The Experimental Study On The Application Of Modified Calcium Based Adsorbent In Enhanced Biomass Gasification For Hydrogen Production

As environmental issues such as global warming becoming more and more serious and fossil energy sources having been increasingly in short supply,the development of new clean energy sources is imminent.Hydrogen is very easy to be used as a new energy source,which has attracted widespread attention.However,fossil fuels are the main sources for generating hydrogen energy.This does not improve China's environmental and energy problems.Biomass as a primary source with a wide range,low prices,and renew,is a very good source for generating hydrogen energy.In a comprehensive view,hydrogen production from biomass gasification is a very promising method for hydrogen production.In this paper,modified CaO sorbents were made by wet mixing method and granulated by extrusion-spheronization method.On the thermogravimetric analyzer,the adsorption performance of CaO adsorbent in 25 cycles was tested.The CaO adsorbent with good adsorption performance were selected.The effect of adsorption temperature on the adsorption performance of CaO adsorbent was investigated.The tabocco stalk and acid-tabocco stalk were selected as raw materials for biomass.It was concluded that the type of CaO adsorbent,the amount of adsorbent added,the gasification temperature,and the ash have a great significance on the hydrogen production for enhanced biomass gasification.The test resulted showed that the addition of the inert carrier modified CaO adsorbent had better adsorption performance than CaO on a thermogravimetric tester.The inert carrier could disperse the CaO particles and delay the sintering of the CaO adsorbent.The molding process reduced the adsorption performance of CaO adsorbent significantly,which was the reason why the extrusion process made dense pore structure of sorbent formed.Doping of 20%by weight microcrystalline cellulose in the CaO sphere particle could improve the adsorption performance of CaO-based sorbent spherical particles.The cellulose in the sorbent rapidly generated a large amount of CO₂ and other gases,which escaped from the spherical particles of the adsorbent,so the specific surface area of the CaO-based sorbent spherical particles were greatly increased,so that the pore structure of the CaO spherical particles was better,but the CaSi75p has a good porosity,so adding cellulose have no effect on the CaSi75p.CaAl75p,CaSi75p,and CaY75p were selected from the CaO-based sorbent.Adding CaO-based sorbent could facilitate the water vapor change reaction,which made hydrogen concentration and yield in the gas composition increased obviously.When CaSi75p was added,the hydrogen concentration and yield during the gasification process were very stable.When the amount of addition for CaSi75p was different,it was found that when the molar ratio of calcium to carbon is between 0 and 1.0,more the addition amount,more the hydrogen concentration and yield.When the molar ratio of calcium to carbon is above 1.0;when the addition of CaSi75p increased,and the hydrogen concentration and yield of the gas components did not almost change.We studied the enhanced biomass gasification at different gasification temperatures of 600 and 650°C,the hydrogen concentration at a gasification temperature of 600°C was very higher.which reached nearly 80%,but the hydrogen yield at a gasification temperature of 650°C was twice as much as the hydrogen yield at gasification temperature of 600°C.With gasification temperature increasing,the water vapor shift reaction is suppressed and biomass pyrolysis,tar reforming and pyrolysis,and gasification of coke are promoted.It was found that the hydrogen concentration and yield by using tabocco stalk were higher,and it could be proved that the active inorganic thing in the ash of tobacco stalk can promote the enhanced biomass gasification.