【作者】 徐熠；

【导师】 高晋生；

【作者基本信息】 华东理工大学 ， 化学工艺， 2010， 博士

【摘要】 煤直接液化工艺大多采用氢气作为氢源,并以循环油为溶剂,本课题与此不同的是通过水煤气变换反应产生的氢气作为氢源,在CO和H2O系统中进行非常规加氢达到煤炭液化的目的。工业上CO的价格远远低于氢气,故可降低煤炭液化的成本,亚临界和超临界水对于有机物有很好的溶解性,用水替代循环油作为溶剂,一方面能进一步降低液化成本,另一方面,对于含水量较高的低阶煤——褐煤,在预处理过程中无需对原料进行干燥,因而可减少褐煤干燥工序,从而节约了投资成本和操作费用,具有现实可行性。本文以胜利褐煤为主要对象,研究了其在CO/H2O系统中直接液化的工艺条件,包括液化温度、停留时间、煤水比、CO初压、催化剂及其用量以及气氛的影响。以350℃条件下的液化产物为主要研究对象,探讨了液化产物的分离,并对液化油、沥青质和液化固体产物进行了详细的分析和表征。同时还选取淮南煤、小龙潭煤、神华煤和兖州煤做了对比试验,考察和比较了5种煤在CO/H2O系统和H2／四氢萘系统中的液化性能。通过对胜利煤加氢液化影响因素的考察,得出胜利褐煤在条件为：350℃,3MPa(起始CO初压),反应停留时间45min,煤水比(质量比)1.2,FeS催化剂,催化剂加入量4wt%下,液化总转化率达到67.28%,其中,油产率44.49%,沥青质产率20.39%,气体产率2.4%,剩余部分为残渣和水分。气体产率较低,通过GC分析,其主要气体产物为CO2、CH4、C2H6、C3H6等烃类气体以及少量的氨气、H2S。对液化油和沥青质进行了GC-MS,FTIR,1H-NMR和13C-NMR分析,与传统的H2／四氢萘系统相比,发现液化产物中大多含有酚类物质。通过核磁氢谱和碳谱,计算了液化油中的H分布和C分布,结合GC-MS和红外分析数据推测了胜利煤的液化产物的分子模型和液化机理。五种煤在CO/H2O和H2／四氢萘系统中的液化试验表明,CO/H2O系统的煤转化率相对于传统的加氢系统要稍低,在CO/H2O系统中,年轻的胜利褐煤的液化总产率要高于其他高阶煤,并且胜利褐煤的液化油产率和沥青质产率均高于其他煤,说明低价煤更加适合CO/H2O系统中的液化。通过对5种煤的液化油和沥青质的氢谱分析计算,发现胜利褐煤和小龙潭褐煤含有较多的羟基、羧基和R-O等,通过对5种煤原煤和各阶段残渣的顺磁共振分析,随着煤化度的增加,g值呈明显的下降趋势。只有胜利煤的线宽△H小幅下降,其它4个煤种的线宽均上升。小龙潭褐煤Ng值最小,淮南煤的Ng值最高。热解使自由基浓度增加,其中胜利煤和小龙潭煤增幅最大,说明低价煤更容易发生热解产生自由基。更多还原

【Abstract】 In the traditional coal liquefaction technology, direct H2 and cycle-oil are used as the hydrogen source and solvent. In this dissertation, the CO/H2O system was used to replace the traditional H2/cycle-oil or H2/tetralin systems. In CO/H2O liquefaction system, the H2 which comes from the water-gas shift reaction is much more active than the common H2 and it is easy to combine with radicals in the hydrogenation. CO is much easier to get, which represents a significant saving when the cost of operation with CO is much lower than the using of H2 in industry. The sub-supercritical or supercritical water plays a very important part in the CO/H2O system. As a substitute of the cycle-oil, supercritical water (SCW) is also a good solvent to the organics and it is much cheaper than the cycle-oil. Besides, the process using water as a medium does not require drying coal which will low down the cost and the energy consumption. This technology fits for the lower rank coal like the brown coal containting hige content of water.In this dissertation, firstly, the influences of Shengli brown coal liquefaction in CO/H2O system was studied including reaction temperature, residence time, ratio of coal and water, initial CO pressure, catalysts and the atmosphere. Liquefied products were analyzed using methods of FTIR, NMR, EPR, GC-MS, GC and MS; and the mechanism of Shengli brown coal liquefaction was inferred. Shengli brown coal, Xiaolongtan brown coal, Huainan bitmminous coal, Yanzhou bituminous coal and Shenhua coal were liquefied both in CO/H2O system and H2/tetralin system to investigate and compare their liquefaction behaviors.The optimized technology parameters of the Shengli brown coal in autoclave are as follow:350℃,3MPa (initial CO pressure),1.2 ratio of the coal and water,4wt% FeS catalyst. Under this condition, the total conversion, oil yield, asphaltene yield and gas yield are 67.28%, 44.49%,20.39% and 2.4%. The gas was analyzed by GC, and the main components are CO2, CO, H2, CH4, C2H6 and H2S. Through the 1H-NMR and 13C-NMR analyzing, it is found that the liquid products of the CO/H2O system contain many phenol and ether. The hydrogen and carbon distribution were calculated according to the NMR spectrum. The molecule model of Shengli brown coal and liquefaction mechanism were speculatedShengli, Xiaolongtan, Shenghuai, Huainan and Yanzhou coal were liquefied in CO/H2O and H2/tetralin system. The conversion in CO/H2O system is lower than it in H2/tetralin system. In CO/H2O system, the total conversion, oil yield of Shengli brown coal were the highest and it indicates that lower rank coal is fit for the liquefaction in the CO/H2O system.The hydrogen distribution of the oil and asphaltene of the 5 coals were calculated through the 1H-NMR spectrum and it is found that there is more hydroxyl and carboxyl in the oil and asphaltene obtained from Shengli and Xiaolongtan coal. These five coals and every step residues were analyzed by EPR and it is indicated that the g factor decrease with the increase of coal rank. The value of△H of Shengli coal decreases and the one of other 4 coal increase after liquefaction. The Ng value of Xiaolongtan coal is the lowest and the one of Huainan is higher. The Ng value increase after liquefaction and the amplitude of Shengli coal is the highest which indicates that the lower rank coal is easier to be liquefied because it may produce much more radicals.更多还原