Study On Pyrolysis Of Pine And Gasification Of Char Catalyzed By Blast Furnace Gas Ash

Pyrolysis and gasification technology is an important way of biomass thermochemical transformation.The introduction of catalysts can effectively improve the effect of pyrolysis and gasification,so it is the key of technology application to find a high-efficiency,cheap and easily available catalyst.Blast furnace gas ash is a by-product of iron and steel industry,which has the characteristics of huge yield,difficult treatment and rich in Fe,Ca,Na,K and other catalytic active substances.It has the potential to catalyze the pyrolysis and gasification of biomass.Based on this,the effects of blast furnace gas ash on the catalytic performance of pine pellets pyrolysis and pine char gasification were studied,which obtained great catalytic effect.It provides a new idea for the low-cost degradation of biomass pyrolysis tar and the preparation of gasification product gas with high hydrogen content.The specific experimental results are as follows:（1）The characteristics of the pyrolysis products of pine pellets are discussed in terms of pyrolysis temperature and catalyst type on the pyrolysis reaction platform.The experimental results show that compared with the action of CK and single catalyst Fe₂O₃,#1 and#2 blast furnace gas ash had a better catalytic effect,and the addition ratio also had a certain impact on the pyrolysis effect.The liquid-phase yield decreased by 5.22%and 6.28%respectively compared with CK and the pyrolysis gas yield increased continuously with the increase of temperature,up to 26.28%and 23.18%under the action of two blast furnace gas ash.At the same time,it can effectively reduce the CO content,increase the volume fraction of H₂ in the pyrolysis gas,and increase by 8.51%and 9.89%respectively compared with the same condition without added catalyst.（2）The pyrolysis volatiles of pine were catalytic reformed with blast furnace gas ash.The results show that the blast furnace gas ash has a good catalytic degradation effect on pine pyrolysis volatiles,and the change of catalyst bed height also has a certain impact on the pyrolysis effect.The liquid phase yield can be reduced by 16.87%and 15.23%respectively at750℃under the action of#1 and#2 blast furnace gas ash.The composition changes of the two pyrolysis gases are mainly reflected in the following aspects.the volume fraction of H₂ in pyrolysis gas is improved by blast furnace gas ash,which is 11.61%and 6.38%higher than that of the same condition without addition,and the proportion of CO is obviously decreased.（3）Dynamics analysis of steam gasification of pine pellets char were studied by gasifier.The gasification reaction rate is positively correlated with the test temperature,which conforms to Arrhenius theorem.The"two-step calculation method"is used to determine that the steam gasification process of pine char follows the shrinking cylinder model,and the reaction order is1/2.The steam gasification activation energy of#1-20%carbon and#2-20%char are slightly higher than that of CK-char,showing a certain inhibition trend.（4）The influence of blast furnace gas ash on steam gasification characteristics was studied by using gasification system,and it was found that the product gas accumulation increases with the increase of temperature during the steam gasification of pine char.Blast furnace gas ash can effectively increase the volume of gasified product gas and the generation of hydrogen-rich gas.Among them,the catalytic effect of#2 blast furnace gas ash is more obvious.Under the steam atmosphere,with the adding with two kinds of blast furnace gas ash,the gasification rate of pine char are 6.25L/g and 6.65L/g,the highest content of H₂ in the product gas is 66.75%and 69.59%,and the ratio of H₂/CO is 1.6 and 2.0 times of CK-char respectively.Blast furnace gas ash can be used as a good catalyst for steam gasification to produce hydrogen-rich gas.