Is desulfurization required before transformation?

Well, if the hydrogen sulfide level is not high, half-water gas can be omitted. At Jincheng No.1 Chemical Plant, the hydrogen sulfide level in semi-water gas was 500 mg/m3; it went straight into the conversion unit without going through semi-dehydration first. Later, since the hydrogen sulfide level in the semi-water gas exceeded 1 g, semi-dehydration was introduced ； At Jiangsu Huaihua (Xuyi Huaihe Chemical), the hydrogen sulfide level in semi-water gas is currently between 300 and 500 mg/m3; it goes straight from the semi-dehydration stage to the conversion stage without any intermediate step, and the system has been operating normally throughout ； Nitrogen Fertilizer Plant, Jiangsu Huahe Group Co., Ltd., Sanhe Farm, Xuyi County, Jiangsu (9395 Armory), Deputy Plant Manager: 0517-8828703; Fax: 0517-8511125

The secretary must be an old Bolshevik, right? Are you from the design institute? ? Still leaving Huaihua, and now taking up a position in Beijing? ?

Strictly speaking, I’m an over-aged member! No, it’s not the land; what is listed above are all customers.

If it’s a tolerance transformation, I guess desulfurization shouldn’t be necessary

If it is less than 150 mg/m3, semi-desulfurization may not be necessary; for materials with high sulfur content, semi-desulfurization will also bring the value to this standard.

Generally, wet desulfurization is used before shift conversion; even in sulfur-resistant shift conversion, desulfurization is necessary in order to reduce the amount of gas that needs to be processed in subsequent stages! !

I’ve never heard of the need for desulfurization before sulfur-resistant shift reaction; if anyone knows, they could list some examples. Current coal gasification processes generally involve a relatively high sulfur content, and desulfurization is carried out after the shift reaction. Sulfur-resistant shift catalysts only specify a minimum sulfur content; there is no requirement for an upper limit, so desulfurization is generally not necessary before the shift reaction. Below are some usage instructions for the catalyst! 4.4 Effect of sulfur content in process gas on catalyst performance: The catalyst possesses both conversion activity and the ability to hydrogenate and hydrolyze organic sulfur; generally, the organic sulfur in process gas can be converted into inorganic sulfur, and its capacity for converting organic sulfur is related to temperature and water vapor partial pressure. A catalyst is only active when its active components are in a sulfided state; therefore, there is no limit on the upper threshold for sulfur content in the process gas. However, a clear requirement exists for the lower threshold – the sulfur content in the process gas must not be below a certain value, otherwise desulfurization will occur and the catalyst will become inactive. Therefore, sulfided catalysts should be avoided from operating under sulfur-free conditions, but steam purging for a short period is permitted. MoS2 is more susceptible to hydrolysis than CoS; there is the following equilibrium reaction between MoS2 in the catalyst and the H2S content in the process gas: MoS2 + 2H2O = MoO2 + 2H2S

Different pressure grades of sulfur-resistant fully low-temperature shift catalysts require different levels of hydrogen sulfide after conversion. At 2.0 MPa, with full low-temperature conversion and a gas flow rate of 92,000, the hydrogen sulfide level after conversion should be kept above 120 mg/m3; otherwise sulfidation will occur. Our plant experienced sulfidation of the catalyst once due to keeping the hydrogen sulfide level at the outlet too low for an extended period of time. Subsequent online sulfidation was carried out, and it was not until the major maintenance that some of the catalysts were replaced. The B303Q fully low-temperature catalyst we use has a very high conversion rate for organic sulfur, over 98%.

Is the hydrogenation conversion of organic sulfur using cobalt and molybdenum very popular these days? Could you help me answer it? What is the manufacturing process?

Reply: Due to the advantage of low steam consumption associated with sulfur-resistant shift processes, full-low-temperature shift is generally used in new plants that employ fixed-bed batch gasification for the production of synthetic ammonia or methanol. This requires the H2S content entering the shift reactor to be around 120 mg/Nm3; otherwise, reverse sulfidation problems will occur. Under such circumstances, atmospheric-pressure desulfurization can meet the requirements (under normal conditions, the H2S content at the outlet of atmospheric-pressure desulfurization can be kept below 80 mg/Nm3), and there is no need to install a shift gas desulfurization unit. Currently, as it becomes more difficult to process bituminous coal in Jincheng, many companies are considering the use of briquetted coal for gas production. This leads to an increase in H2S levels in water gas or semi-water gas; in some cases, these levels reach 2000 mg/Nm3 or even higher. Although desulfurization at atmospheric pressure can meet the required standards by adjusting the processing parameters, it still has a significant impact on subsequent carbon removal processes, necessitating further removal in the desulfurization stage. Due to reasons related to the raw materials, the organic sulfur content in the gas also increases significantly. Therefore, the process design must include a section for the conversion of organic sulfur in order to address this issue. There are two approaches for implementing this: one is to locate the organic sulfur conversion unit outside the shift converter, that is, in an external process flow ； The second is located in the last section of the conversion furnace, that is, within the furnace’s flow path. The authority in the field of organic sulfur conversion in China is the Hubei Institute of Chemistry; you can consult them for details. This post was last edited by zjyang168168 on 2008-7-5 21:29.]