Comparison of the application of 888 desulfurization catalyst and tannin desulfurization catalyst in the desulfurization of semi-water gas

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0 Preface: Our company currently has a production line for hydrogen peroxide with a capacity of 50 kt/a. This line consumes approximately 10.50 km3 of hydrogen per year, as well as around 17.50 KNm3 of semi-water gas per year. This semi-water gas contains about 1.5 g/Nm3 of hydrogen sulfide; if released without treatment, it can have a significant negative impact on the environment. To this end, the company invested in building a semi-water gas tannin desulfurization unit at the beginning of 2008, but the desulfurization effect did not meet expectations. Therefore, in August 2009, it was upgraded to an 888 desulfurization unit, using the 888 desulfurization catalyst from Changchun Dongshi Science and Trade Industry Co., Ltd., which yielded significant results. 1 Conditions of the production facility 1.1 Process parameters (see Table 1 for details) Table 1: Process parameters table 1.2 Equipment configuration (see Table 2 for details) Table 2: List of main equipment 2 Situation regarding tannin-based desulfurization 2.1 Indicators related to the operation of tannin-based desulfurization (see Table 3 for details) Table 3: Indicators for tannin-based desulfurization operation 2.2 Problems existing in the operation of tannin-based desulfurization From the above, it can be seen that our company uses a tannin-based semi-water gas desulfurization system; since its operation began at the beginning of 2008, it has been unstable. Despite continuous improvements and enhancements by technical staff, the desired results have not been achieved, as evidenced by the following issues: (1) High circulation volume of the desulfurization liquid, resulting in high power consumption – approximately 44 Kw/h. ⑵The desulfurization efficiency is poor; the hydrogen sulfide removal rate is only around 50%, which is far from meeting the requirements for desulfurization and has a significant impact on the environment. ⑶The regeneration effect is poor, chemical consumption is high, sulfur production is low, operating costs are high, and the burden on enterprises is significant. ⑷Towers, nozzles, and jet pumps are prone to clogging, so regular shutdowns for maintenance are necessary. 3 Situation of desulfurization using the 888 desulfurization catalyst method ⑴ Since the tannin-based desulfurization process used by the company had been operating unstably for over a year, with desulfurization results not meeting the required standards, this process was replaced with the 888 desulfurization process in October 2009. The 888 desulfurization catalyst produced by Changchun Dongshi Science and Trade Co., Ltd. was used, and the process was adjusted under the guidance of Mr. Yu Zongtian from Dongshi Company. The desulfurization equipment was improved upon the original tannin-based desulfurization system; devices such as an 888 activation tank were added. All process parameters quickly met the required standards, and chemical consumption was significantly reduced. For details on the operation of the process, see Table 3. Table 3: Operation status of the desulfurization process using the 888 desulfurization catalyst 【1】Process requirements must be met; otherwise, the H2S level can drop below 20 mg/Nm3. (2) As can be seen from the above data, by using the Dongshi 888 desulfurization catalyst and making improvements under the on-site guidance of Professor Yu Zongtian, our company’s semi-water gas desulfurization achieved the desired results rapidly. Its advantages are mainly reflected in the following aspects: ① High desulfurization efficiency, exceeding 95%, with stable operation; the hydrogen sulfide content at the outlet can be kept below 20 mg/Nm3 (although, due to the requirements of the subsequent low-temperature conversion catalysts regarding sulfur levels, it is manually controlled between 50 and 100 mg/Nm3). ②It has low consumption: the daily alkali requirement is only half that of the tannin method, and the amount of catalyst used is also low; the total chemical consumption is half of the original level. ③The tower is less prone to clogging, and the pressure difference in the desulfurization tower increases slowly. ④The circulation volume of the desulfurization liquid is low, at about 50% of that in the case using tannin only, and power consumption is low (the circulation pump has been changed from 22 kw to 7.5 kw). 4 Conclusion From the above analysis, it can be seen that using the 888 desulfurization catalyst instead of the tannin-based desulfurization process results in greater stability, a higher sulfur capacity. The ability to remove hydrogen sulfide meets all the process requirements; moreover, the sulfur recovery rate is high, energy consumption is low, and the amount of desulfurizing agent required is minimal. At the same time, the tannin method was replaced by the 888 desulfurization catalyst method for the removal of hydrogen sulfide from semi-water gas; basically no adjustments were needed to the various equipment, only additional small devices such as an 888 activation tank were required.