Staged desulphurization by direct sorbent injection in pulverized-coal boilers

• Published in: Energy (Oxford) Vol. 19; no. 9; pp. 947 - 956
• Main Authors: Makarytchev, S.V., Cen, K.F., Luo, Z.Y.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.1994; Elsevier Science
• Subjects: Air pollution caused by fuel industries; Applied sciences; Boilers; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel selection. Additives; Pollution reduction; Boiler; Experimental result; Desulfurizing agent; Limestone; Temperature effect; Reaction mechanism; Mathematical model; Sorbent; Pulverized coal firing; Successive reaction
• ISSN: 0360-5442
• DOI: 10.1016/0360-5442(94)90079-5

Emissions of the atmospheric pollutants SO 2, H 2S, CO 2, NO, etc. from coal-fired PCC boilers and desulphurization of flue-gas by direct sorbent injection into the furnace are considered. The mathematical model used is based on equilibrium calculations for the coal/water/limestone/air system (50 gas-phase and six solid-phase chemical species) and the concept of freezing of the gas composition at low temperatures. Experiments were performed on bench-scale, coal-fired boilers. To improve the emission performance, a staged-desulphurization method is proposed. This method involves successive sulphur retention in the form of CaS in the high-temperature reducing zone of the furnace and as CaSO 4 in the low-temperature oxidizing zone. It is shown that staging of sorbent supply increases the desulphurization efficiency to 80–85%. Experimental data agree with numerical predictions.