The sulphidation of calcined limestone with hydrogen sulphide and carbonyl sulphide

Abstract

The sulphidation of calcined limestone with H2S , COS and mixtures of H2S and COS was studied in a thermogravimetric analyzer at temperatures between 500 and 700°C. The applied H2S-and COS-pressures corresponded with those in coal gas produced by modern coal gasifiers, i.e. 50-12,000 Pa for H2S and 50-1000 Pa for COS. The reaction orders in H2S and COS as well as the activation energies of the involved reactions were determined. The mechanism of sulphidation was examined by simulating measured conversion vs time behaviour with the grain size distribution model of Heesink et al. (1993, Chem. Enong J. 53, 25-37).

Correlation of H2S and COS in the hot coal gas stream and its importance for high temperature desulfurization

“…Therefore, the most important reaction that determines the concentration of COS and H 2 S in the hot coal gas stream is reaction (1). Some thermodynamic data are available in the literature [2,[6][7][8]16]. The data cover a temperature range from room temperature to 1,200 o C. The reaction is slightly exothermic with the reaction heat of −2.58 kcal/mol and equilibrium constant of 0.53 at room temperature [2].…”

“…In the gasification coal gas stream, the COS content was usually found to be 10-15% of the H 2 S content and formation of COS from H 2 S is certainly taking place [5]. In the literature [2,[6][7][8][9], it has been generally agreed that reaction (1) is responsible for the formation of COS in the hot coal gas stream from H 2 S while the following reaction plays little role.…”

Oxidation of Pure Solid CaS with Ar-O2 Gas Mixture

“…The reaction between H 2 S or SO 2 and dolomite or limestone as a sorbent has been broadly investigated [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The previous works on this subject have been summarized in the review by Cheng et al [24] Due to the reaction of CaS with water or moisture in an atmosphere, stabilization of CaS in the sorbent after offgas desulfurization is necessary before disposal.…”

A stochastic simulation scheme for studying pore volume trapping in a structure of growing particles

“…Typical examples of such gas-solid reactions are deposition reactions used for composite material fabrication by the process of chemical vapor infiltration, 1-3 the deactivation of catalysts through carbon deposition within their structure, 4,5 and the removal of hydrogen sulfide and sulfur dioxide from coal utilization gases using calcined limestones ͑i.e., porous calcium oxide͒. [6][7][8] Since these reactions are driven by fluid species transported through the pore space of the porous medium, reaction can take place only on surfaces that are boundaries to infinitely large subsets of the pore space, and therefore, the porosity and internal surface area values that must be employed in the macroscopic transport and reaction model in the porous medium must include only the accessible values of these quantities.…”