Studies On Design, Preparation And Application Of The Desulfurizer For The High Sulphur Natural Gas

H₂S is a harmful impurity in the natural gas. It can not only cause the pipeline and equipment to be corroded so as to influence the follow up processing (as leading to catalyst poisoning) but also seriously threaten the personal safety, belonging to one of the environmental pollution sources which must be controlled. Up to now, the desulfurizing technology is mostly composed of the dry process and wet process, which is mostly used for the treatment of high or low H₂S content of the natural gas. But to the small and remote natural gas field, both of them are not very suitable, which need high cost with the dry process and low capacity of sulfur, fast inactivation with the wet process. So if we could find a new kind of solid desulfurizer which not only has high capacity of sulfur and long penetration time but also has low cost, simply regeneration method and the moderate operating condition, it would not only have high science value but also have high economic value. In this thesis, supported method and in-situ synthesis method were used to prepare new kinds of solid desulfurizers, which hope to satisfy our needs.The supported method was studied firstly. In this method we used different kind of activated carbon as the support and theα-FeOOH as the active component under the certain process conditions. After the evaluation on the self-designed estimating system under the certain process conditions, we found that theα-FeOOH/AC-m-NO3 desulfurizer was best, which was based on 4M nitric acid treating activated carbon as the support. Comparing different modifier such as nitric acid, urea, phosphoric acid etc., we found that nitric acid was the best. According to the Boehm titration analysis and the structure analysis, we found that the surface chemical properties, quantities and the pore structure were very important for the desulfidation, especially the quantities of carboxyl group and the micropore structure.The in-situ synthesis method was studied secondly. We found that different preparation process condition had different effect to the structure ofα-Fe/SAC desulfurizer, such as activated agent ratio, Fe/coke ratio, carbonize temperature, carbonize time, activated temperature, activated time etc. After the evaluation process, we found that theα-Fe/SAC desulfurizer not only had high surface area and suitable pore size, but also had high activity and efficiency properties to remove H₂S. The best one could almost complete absorption and oxidation of H₂S from 3943.3mg/m3 to 10.6mg/m3 after 7h absorption and oxidation reaction at 70℃, which just using 0.2gα-Fe/SAC desulfurizer as solid desulfurizer and the sulfur capacity as high as 87.80% in 7h, the degree of conversion still as high as 99.73% after 7h. According to the microstructure and the effect of desulfurization, we found that the BET surface area, pore diameter, pore capacity and the content ofα-Fe all could affect the properties ofα-Fe/SAC desulfurizer, which may have suitable proportion for the desulfurization. The micropore diameter is very important to the desulfurization, which may have optimum distribution, and large mesopore diameter and capacity can increase the sulfur capacity. The result obtained indicated that this new in-situ synthesis method not only can get high surface area, large micropore size and many mesopore, but also can use for removing high content hydrogen sulfur in gas.