Abstract: through the use of W801 soda water gas desulfurization of organic sulfurhydrolysis, temperature, gas desulphurization, organic sulfur hydrolysisdesulfurization at normal temperature, the application of comprehensive technology, so that the total sulfur content of the synthesis gas to keep the following in the 0.01ppm term, the methanol catalysts with high catalytic activity and long period running.
Keywords: hydrolysis of finishing temperature methanol soda ash anddesulfurization desulfurization
At present, the industry widely adopted Cu-Zn-Al methanol synthesis catalyst, thecatalyst activity, high selectivity, but the poison is extremely sensitive, easy to poisoning deactivation, life often can not meet the design requirements. From theactual situation of China's methanol industry, in high-pressure methanol, catalyst life shorter, enterprise methanol catalyst production strength of about 5000 tons of/m3 catalyst, medium enterprise 3000~4000 tons of /m3, less than 3000 tons of /m3catalyst is poor, some enterprises use life of only 2 ~3 months. Many factors affect the service life of the catalyst, such as poisoning, sintering, Wu blocked voids,strength decreased, the main influential factor for poisoning and sintering. In the current process, resulting in methanol poisoning catalyst deactivation factorsmainly concentrated in sulfides, ammonia, chloride, metal carbonyl sulfide, which is the most serious. The Wuhan Colin company provides integrated desulfurizationand desulfurizing agent, ensure the methanol catalyst with high activity and long period operation.
2 brief description of the process and desulfurization process
2.1 process
Hebi BMW chemical fertilizer plant, using in high pressure combined methanol production process using coal as raw materials, an annual output of 40000 tons of methanol, the process is as follows:
Coal gas, desulfurization, temperature partial transformation - medium temperatureorganic sulfur hydrolysis, gas desulphurization and decarbonization, normal temperature hydrolysis, desulfurization, methanol synthesis
2.2 wet desulfurization
In synthetic ammonia production, products are mainly of ammonium bicarbonate for agricultural use, the production process by-product dilute ammonia water, can be used for catalytic method of ammonia desulfurization of [1], with the expansion ofmethanol production rate, due to strong volatile, ammonia loss, desulfurization of high cost, poor quality of environment, and trace ammonia in gas is easy to makeactive copper base catalyst of methanol decreased. Therefore, I plant to soda plus W801 efficient desulfurizing agent (modified sulfonated cobalt phthalocyanine)catalytic method. The method is not volatile, eliminating the effects of ammonia,also can remove part of organic sulfur.
Organic sulfur hydrolysis temperature 2.3 transformation
Methanol synthesis requires a higher concentration of CO, transform the low depth.Catalyst for organic sulfur transformation mainly in the following two kinds ofmechanism of [2]:
Hydrolysis: COS + H2O (steam) = CO2 + H2S
CS2 + 2 H2O (steam) = CO2 + 2H2S
Hydrogenation: COS + H2 = CO + H2S
CS2 + 4H2 = CH4 + 2H2S
And the hydrolysis reaction, the hydrolysis reaction is exothermic reaction, high temperature and the equilibrium conversion rate is low, the system low steam / gas ratio, high reaction temperature, H2S concentration, is not conducive to theconversion of organic sulfur. Therefore in the transform heat exchanger with awater solution of tower, raw low furnace temperature, the organic sulfur hydrolysiscatalyst 5M3 Wuhan Colin W505 type (see Table 1 in performance), hydrolysis ofH2S was removed in the variable section. Middle temperature hydrolysis conditions:pressure 0.8Mpa, the temperature 220 ℃.
Table 1 W505 hydrolysis catalyst performance
Project indicators
The appearance of white ball
Particle size, mm 3-5
Bulk density, kg/m3 700-800
The specific surface area, m3/g 300
Compression strength, N/g ≥ 50
Activity (COS conversion),% ≥ 95
2.4 gas desulphurization
In order to make the liquid and stable operation of decarburization, our factory set up converter gas dry desulfurization, the use of W701 iron oxide desulfurizer at ambient temperature (performance, see Table 2.).
Table 2 W701 iron oxide desulfurizer
Project indicators
The appearance of the Yellow Stripe
Particle size, mm 3-5
Bulk density, kg/m3 600-650
The specific surface area, m3/g 300
Compression strength, N ≥ 50
Sulfur capacity of H2S ≥ 95,%
2.4 decarburization
Using the method of NCMA, ~6% content of CO2 decarbonization, also have certain effect on H2S removal. Because it is part of the H2S decarburization, only part ofthe decarbonization gas removal, a W102 pre finishing off tower.