Gasification characteristics of coal char under CO2 atmosphere

The char gasification characteristics and the composition of evolved gases in a CO₂ environment have been studied using a thermogravimetric analyzer (TG) coupled with a mass spectrometer. Three types of coal char were studied: lignite (TXL), sub-bituminous (PRB), and bituminous (KYB). TG results showed that the reactivities of TXL and PRB were higher than that of KYB, and the reactivity of TXL was higher than that of PRB. The characterization of the chars implied that the mineral content in the char plays an important role in the reactivity and that the surface area and pore volume may accelerate the reactivity of chars. The evolved gases from three chars were mainly CO and SO₂. SO₂ was slightly delayed by CO during gasification of TXL and PRB chars, but for KYB, SO₂ and CO formed in the same temperature range, but at higher temperatures compared with TXL and PRB. The CO production of KYB was the best, 0.98 mg mg^?1; and SO₂ was the least, 0.031 mg mg^?1. PRB and TXL chars had similar CO production, but SO₂ in TXL was higher.