栲胶-NTA络合铁体系的脱硫研究

以氧化栲胶(Teos)-次氮基三乙酸(NTA)络合铁为脱硫剂,采用氧化-还原电位法进行脱除硫化氢的研究,考察了该体系用于脱硫的热力学可行性及Teos、NTA络合铁含量对氧化再生时间、脱硫液电位和脱硫过程的影响。结果表明:Teos-NTA络合铁碱性溶液脱硫在热力学上是可行的,铁盐必须加入络合剂后才能稳定存在;脱硫剂电位随络合亚铁浓度的增加而降低,而受Teos的影响较小;络合亚铁浓度增加使脱硫液的氧化再生时间增加,Teos浓度增加有利于缩短氧化时间,但过高的Teos又反而使氧化突跃所需时间延长;模拟脱硫过程实验表明影响脱硫液电位的主要因素是络合铁和硫化氢,与Teos无关,且脱硫液的电位与所含H2S浓度的对数成线性关系,超硫容时电位下降速率变大。

Study on Desulfurization in the Toes-NTA Chelated Iron System

The thermodynamic feasibility of desulfurization in Teos(tannin extract of oxidation state)-NTA (nitrilotriacetic acid) chelated iron system, and the influence of C_(Teos) and C_(NTA-Fe) on oxidation time, potential of desulfurization solution and desulfurization process through redox potential method were studied. The results showed that it was thermodynamically feasible for Teos-NTA chelated iron system to desulfurization; FeSO_4 couldn't stabilize unless complexing agent was added; the potential of desulfurizer was affected mainly by chelated iron, but not by Teos; oxidation time prolonged with increasing of C_(NTA-Fe), shortened with increasing of C_(Teos), but too high C_(Teos) could prolong the oxidation time. Experiment on the potential of simulated desulfurization process demonstrated that only NTA-Fe and H_2S, but not Teos influenced the potential of the desulfurization solution. The potential was linear with log (C_(H2S)) and the downtrend of the potential was more marked when CH_2S exceeded the sulphur-content.