Hydrogen Sulfide Removal and Sulfur Recovery by Chemical Absorption with Heteropoly Compounds

摘要

An innovative approach to natural gas desulfurization involving the use of heteropoly compounds was investigated concerning the performances of the absorbent system and the reactionmechanism between sodium phosphomolybdate (HPAS) and H_2S. The favorable redox potnetial of heteropoly compounds makes it thermodynamic feasible for them to oxidate H_2S to element sulfur and to be regenerated by air. Compared to HPA, HPAS has higher H_2S Removal efficiency and better regeneration performance. The presence of NaCl in HPAS system can accelerate the regeneration process and Na_2CO_3 can improve the absorption rate of H_2S removal. HPAS is still much stable in its chemical property during multiple absorption-regeneration cycles, and the desulfurization product is sulfur. The chemical reaction between HPAS and H_2S was proposed to be : H_2S + Na_2HPMo(VI)_12O_40 -> S arrow down + Na_2H-3PMo(VI)_10Mo(V)_2O_40 i.e., there are two Mo(VI) atoms reduced to Mo(V).