Experimental and kinetic studies on ash fusion behavior: a high‐precision acquisition method for ash fusion temperatures

Abstract

Ash fusion characteristics including ash properties and morphological changes in high‐temperature fusion test were studied among four types of fuels comprising two woody biomass, three straw biomass, two bituminous coals, and three biomass/coal mixtures. On the basis of ash fusion behavior and kinetic analysis of the ash melting process, a high‐precision acquisition method for ash fusion temperatures (AFTs) was developed. First, a reading index of AFTs was proposed; that is, in high‐temperature fusion test, initial deformation temperature (IDT), softening temperature (ST), and fluid temperature (FT) could be identified by the height shrinkage of 38%, 86%, and 98%, or the area shrinkage of 50%, 77%, and 97%, respectively. Kinetic analysis conducted on height/area shrinkage indicated that activation energy was highly related to temperature difference among IDT, ST, and FT, and low activation energy facilitated the enlargement of the temperature differences of ST‐IDT and FT‐ST. XRD patterns illustrated low activation energy had a promotion effect on the generation of higher melting substances such as KAlSi3O8 and CaSiO3, causing the elevation of the ST and FT. At last, a calculation method for AFTs based on activation energy and average height/area shrinkage was performed, which had high repeatability within an average error of ~6°C.

Effects of coal gangue on the ash initial deformation temperature and gasification characteristic of biomass

“…The IDT of biomass ash can be effectively improved by adjusting ash composition, and the typical methods include additives and coal blending. [18][19][20][21] Coal gangue is a kind of solid waste produced in the process of coal mining and washing, and its yield accounts for 10%-25% of the raw coal. Coal gangue has become the largest source of industrial solid waste in China.…”

“…Therefore, it is of great significance to improve the IDT of biomass ash for achieving efficient and clean conversion of biomass in FB gasifier. The IDT of biomass ash can be effectively improved by adjusting ash composition, and the typical methods include additives and coal blending 18–21 …”