【作者】 张艳；

【导师】 张永发；

【作者基本信息】 太原理工大学 ， 化学工程， 2009， 硕士

【摘要】 我国有丰富的煤层气资源,煤层气是优质的清洁碳氢资源。含氧煤层气专指煤矿开采过程中为防止瓦斯爆炸而抽排出的甲烷含量在20%-45%的煤层气。这种煤层气压力低,甲烷含量低,且混有10%左右的氧气,极易发生爆炸,给加工、运输和利用带来了困难。大量含氧煤层气放空浪费资源,污染环境。含氧煤层气脱氧已成为其开发利用的关键和重大课题。硫化物具有很强的还原性,可在一定的温度下与含氧煤层气中的氧发生反应,从而脱除含氧煤层气中的氧,同时使硫化物转化成硫酸盐,然后用还原性气体还原硫酸盐,使其转化为硫化物,再生硫化物可循环利用于含氧煤层气的脱氧。根据上述理念,本文开展了基于硫化物-硫酸盐循环的含氧煤层气的脱氧研究,详细考察了硫化物在含CH₄气氛下的脱氧特性及其再生特性。脱氧特性研究主要包括脱氧剂的选择、脱氧催化剂和脱氧剂载体的考察、流速及温度等因素对脱氧反应的影响;还原再生特性的研究主要有还原催化剂的选择、还原温度和还原性气体（CO、H₂）的流速等因素对反应的影响。此外,对脱氧反应和还原再生反应的热力学以及脱氧反应的动力学进行了初步研究。研究的创新性主要成果和结论如下。（1）综合考虑硫化物和其对应硫酸盐的性质,开发了采用硫化物脱氧,然后用还原性气体还原硫酸盐生成硫化物,并用该硫化物循环脱氧的新方法。（2）在低温阶段硫化钠的脱氧效果明显高于硫化钙的脱氧效果。添加Cu、Fe、Ni金属催化剂可以明显促进硫化钠的脱氧反应,其中Cu催化剂的效果最好,和空白的相比反应温度提前,氧化增重率提高了5%。颗粒状硫化钠脱氧和分子筛载硫化钠氧化相比,分后者的脱氧效果明显提高。分子筛脱氧的最佳脱氧反应温度为300⁴00℃,氧含量可降至1%左右。（3）硫酸钠的还原转化过程可以分成两段:第一段（<640℃）随反应时间增加硫酸钠转化率缓慢增加;第二阶段（>640℃）随反应时间增加硫酸钠还原转化率迅速增加,2h后趋于稳定。在温度低于600℃时,各催化剂无明显活性。当温度高于600℃,氧化铁的催化活性优于石棉铜和硝酸镍的催化活性。在氧化铁催化剂条件下,氢气的加入可有效提高反应转化率,当氢气流速增加到30ml/min时,还原转化率达72.3%。在低温阶段（<600℃）还原性气体（CO、H₂）中H₂的比例对反应的转化率影响较大,温度较高时（>600℃）影响较小,温度与硫酸钠转化率之间呈现倒“V”字形。（4）对脱氧剂硫化钠的脱氧反应和脱氧剂再生的热力学进行了研究,根据实验数据建立了平衡常数K值和反应温度的关系。lnK_氧化 = 3.59 + 778.38/T lnK_还原 = 2.06 + 760.87/T（5）用差热热重天平,采用差减微分法对硫化钠的脱氧反应进行动力学研究,得到分子筛载硫化钠脱氧和Ni催化脱氧的动力学方程如下:分子筛载硫化钠脱氧: Ni催化脱氧:更多还原

【Abstract】 China has abundant coal mine methane resources （CMM）, which is high-quality clean energy. Rational utilization of CMM not only mitigate environmental pollution, but provide stable energy supply which promote economical sustainable development. Due to containing a little oxygen, the low pressure Oxygen-bearing CMM which is inclinable to blast. It is difficulties to process and transport, so phenomenon of emptying is very graveness.In research, our groups have found that sodium sulfide has strong antioxidant. In certain temperature, the deoxygenation of CMM can occurre. Regeneration of reductant used in oxygen-containing coal bed gas deoxidation can occurre under reductant atmosphere. In this paper, the deoxygenation and regeneration character were investigated, a preliminary study on kinetics and thermodynamics.The innovation and conclusion as follows:（1） Considering the property of suifides and their corresponding sulfates, our group develop a new method ,which is sulfide deoxygenation,and then use reducing gas to reduce sulfates to make sulfides to redeoxygenate.（2） The sodium sulfide has better oxidizability than calcuim sulfide in the range of 200⁶00℃. The molecular sieve is the best one in four catalysts, which can improve conversion obviousely. Compared, low flow gas in feed is apt to improve conversion. The Conversion of Na₂S is not related with the reaction temperature.Taking into account the conversion and economy, the best reaction temperature ia about 300⁴00℃,and O₂ content in the off-gas can be reduced to 1%。（3） Regeneration of reductant used inoxygen-containing coal bed gas deoxidation was performed in a quartz tubular reactor temperatures ranging from 500 to 700℃. The gas composition was detected by an on line gas chromatograph. The results show that the temperature is one of the important factors influencing the regeneration of oxygen-containing coal bed gas deoxidation reductant. The conversion of the Na₂SO₄ can be grossly classified into two stages. In the first stage （<640℃）, the conversion of the Na₂SO₄ drops smoothly, in the second stage（>640℃） , the conversion of Na₂SO₄ increases sharply, which maintains constant after 2 h. When the temperature is low 600℃, all catalysts are not active. The activation of Fe2O3 is higher than other three kinds of catalysts when the temperature is high than 550℃. Adding H₂ in feed gas has a significant influence to the conversion of Na₂SO₄, and the low temperature shows obvious influence. The relation between Na₂SO₄ conversion of and temperature accord with“Λ”model. The content of CO₂ in product gas decreases with the H₂ ratio in feed gas.（4）The sulfide deoxygenation and regeneration of reductant thermodynamics were studied in a thermo-gravimetric analyzer and a quartz tubular reactor. The formulae of thermodynamics as follows: lnK_oxidation = 3.59 + 778.38/T lnK_reduction = 2.06 + 760.87/T（5）The sulfide deoxygenation kinetics were studied in a thermo-gravimetric analyzer. The formulae of sulfide deoxygenation kinetics as follows: Molecular sieve as a deoxygenating carrier : Ni as a deoxygenating catalyst :更多还原