Coal Flash Hydropyrolysis

Catalytic Effect of Various Metals Loaded by Ion-Exchange Method

Abstract

Effects of various metal ions like K, Na, Ca, Fe and Ni, which were loaded to Loy Yang brown coal by ion-exchange method, on flash hydropyrolysis were investigated, using a heated grid reactor.
Raw coal and coal in metal forms were heated in 70 atm hydrogen at 500°C/s to temperatures of up to 1000°C and the yields of char, tar and individual gaseous products were determined as a function of temperature history. It was found that alkaline or alkaline-earth metals showed little catalytic effect, whereas Ni and Fe significantly promoted hydropyrolysis of coal. The addition of 7.3‰ Ni resulted in the increase of the overall carbon conversion and carbon conversion to liquids by 15‰ and 5‰ respectively. Carbon conversion to methane increased by 10‰, whereas carbon conversion to benzene 3.5‰ only below 800°C . The overall carbon conversion increased by 10‰ in the case of 4.3‰ Fe-loading and further increase by 20‰ was observed when increasing Fe loading to 8.5‰. This increase was mainly due to the production of liquids. At the same time, the increases in methane and benzene were. also achieved.