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Application of the JTL-ll advanced desulfurization process: The purification of raw gas for ammonia synthesis is one of the important measures for saving energy and reducing consumption, especially in the ammonia and methanol synthesis process. Although the feed gas has been desulfurized and decarburized, its total sulfur content remains at (0.3–0.5)×10⁻⁶; it is necessary to further reduce this level to below 0.1×10⁻⁶ in order to ensure the service life of the methanol catalyst. In 1995, our factory adopted a new advanced desulfurization technology developed by the Hubei Chemical Research Institute, namely the JTL—1 special activated carbon for hydrolysis-based desulfurization. This technology involves a \"sandwiched cake\" process composed of a T504 hydrolysis catalyst and a T101 desulfurization agent. Years of production experience have shown that this process is highly effective for the production of methanol and synthetic ammonia. 1 Process flow: The feed gas, which contains a total sulfur content of (0.3–0.5) ×10⁻⁶, undergoes decarburization. After that, a vapor-water separator is used to remove the water droplets, thereby ensuring the sulfur capacity of the desulfurization agent. Entering the first desulfurization tower, H2S is removed; after that, the mixture is heated in a heater to raise its temperature to 50°C, the temperature at which it becomes active. It then enters the hydrolysis tower, where the organic sulfur is hydrolyzed. Following cooling, it passes through the second desulfurization tower to have any remaining sulfur removed. The raw gas, whose total sulfur content is less than 0.05×10‑6 after desulfurization, is fed into the methanol system via four stages of compressors (see Figure 1). http://www.yf116.cn/jishuwang/upload/0601241041002439.jpg 2 Loading status of desulfurization agents: The first and second desulfurization towers are each filled with 30 m3 of special activated carbon. To maintain a certain space velocity, this carbon is loaded in 3 sections, with 10 m3 in each section; three temperature measurement points are installed in each section to ensure that the temperature does not exceed 35°C. The second hydrolysis tower is equipped with a catalyst volume of 30 m3, which is filled in two sections, with 15 m3 in each section; the space velocity is maintained between 1,500 and 2,000 h⁻¹. The catalyst layer is equipped with 3 temperature measurement points to maintain the temperature at ≥50°C, and temperature changes are monitored during operation. 3 Operation Status The design of this unit is tailored to an ammonia synthesis capacity of 110,000 t/year. In October 1995, during operation, the ventilation rate was 70,000 tons of total ammonia per year; the hydrolysis temperature was maintained between 45 and 50°C. After 2 months of operation, the temperature increased to 55°C. The analyzed total sulfur content at the inlet was 0.45 mg/m3, while it was 0.05×10‑6 at the outlet. At the beginning of 1996, when the methanol plant was put into operation, the total sulfur content in the feed gas after purification was still (0.05–0.06) ×10⁻⁶. Due to the thorough removal of H2S, the methanol catalyst in the first reactor lasted for 2 years and 6 months; the replacement interval for the synthesis catalyst was extended from 1 year to 2–3 years, and the copper consumption during copper washing was also significantly reduced. Over the 8 years of operation, the methanol catalyst has been replaced 5 times; the desulfurization agent is still in use, with trace sulfur levels in the feed gas remaining within acceptable limits. The production capacity of the methanol catalyst is 3,771.4 t/m3. At present, the service life of methanol catalysts exceeds 1 year due to the high CO2 content in the feed gas, which is 3.2%, as well as the high water content in the crude alcohol. When the gas flow rate increases, the oil content in the crude alcohol before it enters the tower decreases, and this oil contamination reaches the catalyst layer, affecting its activity. For precise desulfurization, a total sulfur content of no more than 0.1×10‑6 in the methanol feed gas indicates that the precise desulfurization process truly serves to purify the gas. 4 Conclusion (1) The JTL-1 precision desulfurization process is advanced, reliable, and easy to operate; it requires no dedicated personnel for management, thus saving on operational costs. (2) The catalyst life of methanol is extended, reducing operating costs. (3) The desulfurizer has a high sulfur capacity; it does not require regeneration, and only proper control of the hydrolysis temperature is needed. (4) It protected the methanol catalyst and the ammonia synthesis catalyst, reducing copper consumption in the copper washing process. If methanation is used in place of copper washing, it can also protect the methanation catalyst.