利用含硫化氢尾气一步法合成硫脲的研究

Study of Synthesizing Thiourea from Tail Gas Containing H_2S by One - step Method

采用H2S尾气和含氮量20％以上的CaCN2(石灰氮)水解物直接反应,一步法生成硫脲。考察了温度、时间对反应的影响。该反应分两个阶段:第一阶段为H2S的吸收过程,受其溶解度影响,常压下有利反应的温度为35℃左右,反应液中除了溶解的H2S和未水解的CaCN2外,主要有Ca(SH)2和H2CN2及少量副反应生成的尿素;第二阶段主要是Ca(SH)2和H2CN2继续反应生成CS(NH2)2(硫脲),反应主要受硫脲生成速度影响,温度控制在80-85℃,时间不超过6 h。该法所得硫脲产品按ZBG17013-88分析为合格产品。

Thiourea is prepared from gas tail containing H2S and CaCN2 ( calcium cyanamide) containig ≥20% nitrogen by one - step method. The effects of reaction temperature and reaction time on reaction are examined. The reaction includes two stage :H2S absorption process in which solubility of H2S has effects on absorption and the temperature of about 35 ℃ is suitable at normal pressure and there is majority of Ca(SH)2 and H2CN2 and minority of urea produced by side reactions in addition to solubilized H2S and unhydrolyzed CaCN2, and production of CS (NH2)2 by reaction of Ca(SH)2 and H2CN2 in which the speed of thiourea formation has influence on the reaction with the temperature controlled between 80-85℃ , reaction time less than 6 hours.