Effect of dimethyl ether synthesis on methanol- and iron-making integrated system

In a previous study the catalysts for synthesizing dimethyl ether ((CH3)(2)O, DME) from blast furnace gas were successfully developed for increasing methanol (CH3OH, MeOH) yield. The objective of this study is to design a new MeOH-Iron production system through DME synthesis based on the results, to evaluate a system from exergy concept and to compare with a previously proposed MeOH-Iron production system. Then, effect of the systematic combination and auxiliary fuel injections to a blast furnace on exergy consumption in the system was mainly assessed. As a result, the exergy consumption of the new system for hot-metal production became 10% lower than the previous one. At the same time, its exergy consumption for MeOH production decreased as much as 36% of the previous one, showing thermodynamic advantage of DME synthesis. The amount of MeOH production had great dependence on a kind of auxiliary fuels through top gas composition of a blast furnace (BF). It was concluded that MeOH production with DME synthesis and the injection of COM or PC to BF was best systematic combination for maximizing MeOH production from BF offgas.