Preparation Of Oxygen Carrier And Technology Study For Chemical Looping Gasification

Cu-based oxygen carriers with olivine as supporter have been prepared using impregnation method,and the oxygen carriers have been used for steam gasification of coal char to evaluate its reaction activity in a fixed bed reactor.The influence of technical conditions such as temperature,S/C and oxygen carriers/char ratio on gasification of coal char has been investigated.The reaction activity after high temperature regeneration and cycling stability have also been investigated.What's more,absorption ability of calcined limestone has been tested in the fixed bed reactor,and a dual chemical looping gasification technology has been designed with the help of Ca-based absorbent.It is shown that the oxygen carrier has high reaction activity for the gasification of coal char,but the oxygen carrier also leads to drop of syngas.The technical conditions have remarkable influence on the gasification of coal char: higher gasification temperature and S/C are conducive to the increase of carbon conversion and syngas yield;increase of CuO loading amounts on oxygen carrier and oxygen carrier/char ratio results in higher carbon conversion but lower syngas yield.The reaction activity of oxygen carrier has not been reduced after regenerating at high temperature because the transfer of Fe in olivine bulk phase.And the oxygen carrier still has high activity after multiple regeneration at 950?,which indicates the inert components in olivine could inhibit sintering of the supported Cu/CuO.It is shown that the calcined limestone has high activity at 500-600? with a CO2 conversion of 84%.It is also shown that higher temperature could reduce CO2 conversion,especially in the steam atmosphere.There is not obvious drop of sorbent activity after multiple regeneration,which indicates the calcined limestone could meet the requirements of designed technology.A dual chemical looping gasification technology has been designed with Ca-based absorbent to overcome the high CO2 concentration.Oxygen carrier has been employed to transfer oxygen between the fuel reactor and the air reactor for the fuel gasification,and Cabased absorbent has been employed to absorb CO2 for the purification of syngas by cycling between the sorption reactor and the calcined reactor.