Based On The Blast Furnace Slag Waste Heat Recovery Of Biomass Gasification Experimental Research

Blast furnace(BF)slag---a byproduct of steelmaking industry,contains a large amount of sensible heat and is composed of some metal oxides,which demonstrates a better catalytic performance in improving tar cracking,reducing the activation energy for tar conversion and enhancing catalytic reforming of Cn Hm.Based on this,a heat recovery system from the heat of BF slag,which will generate hydrogen-rich gas by utilizing the endothermic reactions of biomass catalytic gasification was presented.In this paper,liquid BF slag is made into liquid-solid transition state particle by centrifugal granulation and taken as heat carrier of biomass gasification in moving-bed reactor.This will achieve the recycling and conversion of the sensible heat of BF slag,converting the low-grade liquid BF slag waste heat into hydrogen energy.The results indicated that:Investigate the movement and heat transfer laws of heterogeneous particles(BF and biomass)in moving bed reactor,as well as establish the heat transfer model.The resluts showed that the movement states of particles was divided into dense phase accumulation flow and fully mixing flow.Spherical shell heat model was used to describe this heat transfet process.The effects of temperature of BF slag,and on gasification performances of biomass were investigated.BF slag showed good catalytic activity in tar cracking and gas reforming.Increasing BF temperature and decreasing its particle size can decrease tar content of gasification product and improve the quality of hydrogen-rich gas.At the optimum conditions(BF slag with particle size between 2 mm were taken as heat carrier and catalyst),the tar content in gas was 2.52%,the gas yield reached 1.65Nm3/kg and the hydrogen content reached 53.22%.Through the analysis of various data(the composition and production of raw material and product)during reactions,a mass balance was established,combined with the law of energy conservation,the energy balance relation is also deduced.The resluts showed that for the gasification system using waste heat from BF slag,the cooling efficiency,energy recovery rate were 51.44%.This project will lay important foundation for the waste heat recovery of blast furnace slag accompanying with the transformation of biomass for the production of hydrogen.