| Our country faces severe problems in resource and environment,since unrenewable energies are exhausted,greenhouse gases are exposed widely.Iron and industry is the pillar industry of our country,which is a country with a high steel production,and in the process of the formation of iron,a lot of blast furnace slag which the discharge temperature is up to 1500℃ is discharged.The key point is to seek a suitable heat resource since biomass gasification process can use renewable resource effectively,however the gasification temperature is quite high.This article proposes a noble method to recycle the waste heat of blast furnace slag,which is slagging granulating blast furnace slag as heat carrier to gasify biomass with CO2.Biomass includes biomass pyrolysis and biomass char gasification.So this project mainly study conversion and production of biomass pyrolysis and gasification.(1)Thermogravimetric experiments on biomass pyrolysis using blast furnace slag as heat carrier showed that with the increase of heating rate,the heat hysteresis of biomass pyrolysis becomes apparent gradually.The smaller size of biomass particle induces heat and mass transfer,increasing the conversion rate of biomass pyrolysis.While the supplementation of blast furnace slag has no effect on biomass pyrolysis conversion rate.(2)Based on 19 types of reaction models,selected by Coats-Redefern method,it is found that pyrolysis of straw and peanut shell comply with model of D3,while corn stalk pyrolysis complies model of Di.Establishing reaction dynamics formula,it is noticed from dynamics parameters that when increase the heating rate,decrease the biomass particle size,biomass pyrolysis activation energy reduced,which advantages pyrolysis reaction.(3)Thermogravimetric experiments on biomass char gasification show that:increasing gasification temperature induces biomass char gasification reaction.When increase heating rate,the heat hysteresis of biomass char gasification becomes apparent gradually.Blast furnace slag catalyses biomass char gasification reaction in an extent,when increase the supplementation of blast furnace slag,it catalyses the reaction more effectively.Peanut shell is most likely to gasification while straw char gasification is the hardest.(4)Reaction dynamics model of biomass char gasification with CO2 is selected.The calculation results show that the type of biomass char and supplementation of blast furnace slag influence reaction model in an extent.Biomass char gasification dynamics parameters and reaction formula can be established based on the model.The dynamics parameters show that when increase the supplementation of blast furnace slag,activation energy of biomass char gasification reduce gradually.Reaction dynamic energy and formula differs among biomasses.Biomass char gasification activation energy in descending order is:straw char>corn stalk char>peanut shell char.(5)Studying the influence of blast furnace slag on the production of biomass pyrolysis through the thermal-state experiment.Results show that increase the temperature can induce the biomass pyrolysis reaction.Blast furnace slag induce the splitting of bio-oil which raise the gases production rate.H2 content in the gas is raised as inducing the pyrolysis of biomass.The higher temperature advantages biomass gasification.When CO2/C=1:1 reaction of biomass char gasification process sufficiently.Blast furnace slag induces splitting of bio-oil and biomass char gasification.Adding CO and H2 content in the produced gas.Meanwhile blast furnace slag can catalyze the biomass gasification.By comparison,CO2 gasification of peanut shell haves the best effect.(6)Blast furnace slag can provide heat for biomass gasification,which can catalyze the biomass gasification.So blast furnace slag use as high quality heat carrier of biomass gasification,... |
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