黄铁矿对龙口油页岩有机质热解及其半焦官能团的影响
发布时间：2018-08-26 15:45
【摘要】：我国资源赋存具有“富煤、贫油、少气”的特点,石油储采比仅为11.4年,对外依存度超过60%。我国油页岩资源丰富,其干馏产生的页岩油可以代替石油。油页岩热解过程中,黄铁矿中的硫会迁移到产物里,严重的污染了环境、腐蚀了设备。另一方面,黄铁矿又会对热解过程产生影响。因此,研究黄铁矿对油页岩热解过程的影响意义重大。为了排除其他矿物质对油页岩干馏的影响,本文采取酸洗的方法制备龙口油页岩有机质,详细分析了酸洗前后油页岩中矿物质和各种官能团的变化情况。在水平炉干馏试验台上,研究了氧化铁、单质硫和黄铁矿对油页岩有机质热解产物产率、不凝气释放以及半焦官能团的影响。通过对龙口油页岩酸洗前后XRD和FTIR分析,发现采用HCl-HF-HNO3逐级酸洗的方法可以脱除98.5%的灰,制得较为纯净的有机质,但会对有机质的结构产生一定影响。酸洗会促使芳香烃结构向苯环二取代方式转变,同时使有机盐转化为有机酸,提高羧酸和酚羟基含量;对于脂肪结构,酸洗会增加不对称CH2所占比例,造成脂肪链长度增大,而对于羟基来说,酸洗会在一定程度上破坏OH-O的氢键结构。对酸洗前后油页岩进行热重实验,结果表明酸洗会降低热解起始温度和终止温度,增大热解速率,但基本不影响最大失重峰的温度范围,这说明酸洗并不会显著改变有机质的主体结构。龙口油页岩酸洗除去的矿物质对热解表现为抑制作用。通过对半焦官能团的红外谱图分析,发现在热解终温500℃、停留时间40min时,有机质基本已经分解完全。热解会使脂肪长链断裂,含氧官能团比例下降,其中羧酸已完全反应。对芳香烃而言,热解会使芳香氢取代程度升高,取代方式向氢含量减少的方向进行。氧化铁、硫、黄铁矿均会促进芳香烃的取代,过量的氧化铁和黄铁矿会使苯环的取代方式向苯环三取代进行,硫会使苯环的取代方式向苯环四取代进行。3种添加剂都会抑制大分子的缩合,使半焦中CH2/CH3的值不断升高。当添加40%的硫时,红外谱图中2870cm-1处对称的CH3伸缩振动峰的强度明显增强,表明过量的硫会促使焦炭中芳香环开裂,增加支链化程度。热解过程中,氧化铁、硫、黄铁矿均对有机质大分子结构的断裂起到促进效果。氧化铁和硫均降低了焦油的产率,促进了不凝气的生成;随着黄铁矿添加量的增大,焦油产率先下降后上升,气体产率先上升后下降。热解气CO和CO_2的生成总是先于CH_4和C_2H_6。氧化铁会提高CO_2的产率,降低CO、CH_4和C_2H_6的产率;硫会提高CO的产率,降低CO_2、CH_4和C_2H_6的产率,同时,硫的加入会使这4种气体开始生成的时间推后;黄铁矿会提高CO_2的产率,而CO、CH_4和C_2H_6的产率先升高后下降,在添加量2%时达到最大值。
[Abstract]:The occurrence of resources in China is characterized by "rich coal, lean oil and less gas". The ratio of oil storage to production is only 11.4 years, and the degree of external dependence is more than 60%. China is rich in oil shale resources and the shale oil produced by its retorting can replace oil. During the pyrolysis of oil shale, sulfur in pyrite will migrate to the product, which will seriously pollute the environment and corrode the equipment. On the other hand, pyrite will affect the pyrolysis process. Therefore, it is of great significance to study the influence of pyrite on the pyrolysis process of oil shale. In order to eliminate the influence of other minerals on oil shale retorting, the organic matter of Longkou oil shale was prepared by acid pickling method. The changes of minerals and various functional groups in oil shale before and after pickling were analyzed in detail. The effects of iron oxide, elemental sulfur and pyrite on the yield of pyrolysis products of oil shale organic matter, the release of uncondensed gas and the functional groups of semi-coke were studied on a horizontal furnace dry distillation test rig. By analyzing the XRD and FTIR of Longkou oil shale before and after pickling, it is found that 98.5% of the ash can be removed by using the method of HCl-HF-HNO3 pickling step by step, and the pure organic matter can be prepared, but it will have a certain influence on the structure of organic matter. Acid pickling can change the structure of aromatic hydrocarbons to benzene-ring disubstituting, at the same time, the organic salts can be transformed into organic acids and increase the contents of carboxylic acids and phenolic hydroxyl groups. For fat structure, pickling will increase the proportion of asymmetric CH2 and increase the length of fat chain. For hydroxyl groups, acid pickling can destroy the hydrogen bond structure of OH-O to some extent. The thermogravimetric test of oil shale before and after pickling shows that acid pickling can decrease the starting temperature and termination temperature of pyrolysis and increase the pyrolysis rate, but it has no effect on the temperature range of the maximum weight loss peak. This shows that pickling does not significantly change the main structure of organic matter. The minerals removed by acid pickling of Longkou oil shale inhibit pyrolysis. By analyzing the infrared spectrum of the functional groups of semi-char, it is found that the organic matter has basically been completely decomposed when the final pyrolysis temperature is 500 鈩，
本文编号：2205375
[Abstract]:The occurrence of resources in China is characterized by "rich coal, lean oil and less gas". The ratio of oil storage to production is only 11.4 years, and the degree of external dependence is more than 60%. China is rich in oil shale resources and the shale oil produced by its retorting can replace oil. During the pyrolysis of oil shale, sulfur in pyrite will migrate to the product, which will seriously pollute the environment and corrode the equipment. On the other hand, pyrite will affect the pyrolysis process. Therefore, it is of great significance to study the influence of pyrite on the pyrolysis process of oil shale. In order to eliminate the influence of other minerals on oil shale retorting, the organic matter of Longkou oil shale was prepared by acid pickling method. The changes of minerals and various functional groups in oil shale before and after pickling were analyzed in detail. The effects of iron oxide, elemental sulfur and pyrite on the yield of pyrolysis products of oil shale organic matter, the release of uncondensed gas and the functional groups of semi-coke were studied on a horizontal furnace dry distillation test rig. By analyzing the XRD and FTIR of Longkou oil shale before and after pickling, it is found that 98.5% of the ash can be removed by using the method of HCl-HF-HNO3 pickling step by step, and the pure organic matter can be prepared, but it will have a certain influence on the structure of organic matter. Acid pickling can change the structure of aromatic hydrocarbons to benzene-ring disubstituting, at the same time, the organic salts can be transformed into organic acids and increase the contents of carboxylic acids and phenolic hydroxyl groups. For fat structure, pickling will increase the proportion of asymmetric CH2 and increase the length of fat chain. For hydroxyl groups, acid pickling can destroy the hydrogen bond structure of OH-O to some extent. The thermogravimetric test of oil shale before and after pickling shows that acid pickling can decrease the starting temperature and termination temperature of pyrolysis and increase the pyrolysis rate, but it has no effect on the temperature range of the maximum weight loss peak. This shows that pickling does not significantly change the main structure of organic matter. The minerals removed by acid pickling of Longkou oil shale inhibit pyrolysis. By analyzing the infrared spectrum of the functional groups of semi-char, it is found that the organic matter has basically been completely decomposed when the final pyrolysis temperature is 500 鈩，
本文编号：2205375
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