Methanol synthesis catalyst

Currently, copper-based catalysts are the most widely used in China. They are mainly classified based on the copper content in the catalyst. In the production of monohydric alcohols, C306 and C307 are the most commonly used. I’ve heard that Nanhua Institute has introduced C308, but I haven’t heard of any applications of it yet.

I heard that the monolcohol catalyst produced by Southwest Institute is also good; its model number is XNC98. I wonder if there are any users on this forum who have used this type of catalyst. Could we discuss its performance here?

Copper-based catalysts for methanol synthesis: Methanol synthesis catalysts can generally be divided into zinc-chromium catalysts, copper-based catalysts, palladium-based catalysts, and molybdenum-based catalysts. 1) Zinc-chromium catalyst: The zinc-chromium (ZnO/Cr2O3) catalyst is a high-pressure solid catalyst that was first developed by the German company BASF in 1923. Zinc-chromium catalysts have low activity; to achieve higher catalytic activity, the operating temperature must be between 590 K and 670 K. To achieve a high conversion rate, the operating pressure must be between 25 MPa and 35 MPa; hence, it is known as a high-pressure catalyst. Zinc-chromium catalysts are characterized by: a) good heat resistance, enabling them to withstand overheating conditions with temperature differences of over 100°C; b) insensitivity to sulfur; c) high mechanical strength; d) a long service life, wide range of applications, and easy operation and control. However, compared to copper-based catalysts, they have lower activity, lower selectivity, and make distillation more difficult due to the complexity of impurities in the product. Since the mass fraction of Cr2O3 in such catalysts is as high as 10%, it becomes one of the major sources of chromium pollution. Chromium is toxic to the human body, and such catalysts are being phased out gradually. 2) Copper-based catalysts: Copper-based catalysts are catalysts for methanol synthesis at low temperatures and pressures. Their main components are CuO/ZnO/Al2O3 (Cu-Zn-Al), and they were developed successively by the British company ICI and the German company Lurgi. The operating temperature for low (medium) pressure copper-based catalysts is 210°C to 300°C, with a pressure of 5 MPa to 10 MPa; this is much lower than the temperature used in traditional synthesis processes, which is favorable for the equilibrium of the methanol reaction. Its characteristics are: a) good activity, with a one-step conversion rate of 7% to 8%; b) high selectivity, exceeding 99%, and its impurities consist only of trace amounts of methane, dimethyl ether, and methyl formate, allowing for the production of high-purity methanol; c) poor resistance to high temperatures, and sensitivity to sulfur. Currently, copper-based catalysts are primarily used in the industrial synthesis of methanol. 3) Palladium-based catalysts: Since copper-based catalysts can achieve a selectivity of over 99%, the focus in the development of new catalysts is on further improving their activity, enhancing their thermal stability, and extending their service life. Most research on new catalysts is based on transition metals, precious metals, etc., but compared to traditional (or conventional) catalysts, their activity is not ideal. For example, catalysts whose main catalytic component is the precious metal palladium show only a modest increase in activity, and the selectivity of some of these catalysts even decreases. 4) Molybdenum-based catalysts: Copper-based catalysts are important catalysts in the methanol synthesis industry. However, the presence of small amounts of H2S, CS2, Cl2, etc. in the feed gas can easily lead to catalyst poisoning; therefore, there is increasing interest in the development of sulfur-resistant catalysts. Zhang Jiyan from Tianjin University developed a MoS2/K2CO3/MgO-SiO2 catalyst for the synthesis of sulfur-containing methanol. Under conditions of a temperature of 533 K, a pressure of 8.1 MPa, an space velocity of 3,000 h-1, a ratio of φ(H2) to φ(CO) of 1.42, and a mass concentration of sulfur at 1,350 mg/L, the conversion rate of CO was 36.1% while the selectivity for methanol was 53.2%. Although this catalyst has a high one-pass conversion rate, its selectivity is only 50%, and the downstream treatment of by-products is complex; it is still a long way away from industrial application.

The molybdenum-based catalysts mentioned above can withstand sulfur exposure, and they do hold great promise; I wonder if there have been any new developments recently

We welcome all marine industry professionals to continue the in-depth discussion on what are the different grades of methanol catalysts available both domestically and internationally! !

The copper-based catalyst of model MK121 provided by the Danish company Topsoe

British ICI51-7, 51-8, etc

The fundamental issue has not been resolved: what exactly are the differences between catalysts under different operating conditions? Is there anyone skilled who can help solve this?

The high-pressure methanol catalyst, model C301, was developed and put into use by the Research Institute of Nanjing Chemical Group in the 1970s. It was created to serve the more than a dozen high-pressure methanol synthesis units with an annual production capacity of 20,000 tons that were introduced from the former Soviet Union at that time; the reaction pressure in these units ranged from 2.8 to 3.2 MPa. During operation of a high-pressure methanol plant in Henan, an old-style three-tube type 800 methanol synthesis tower was used, filled with approximately 10 tons of C301; the highest space velocity was 28,000, with a daily production of 250–280 tons of crude methanol. Although the compression and cycling power consumption is high, the output is quite impressive. The space-time yield reached 1.67 tons of methanol per m3 of catalyst, and this load was maintained for over a year under normal gas purification conditions. At the Jiangshan Fertilizer Plant in Zhejiang, high-pressure methanol in series with high-pressure methanation, designed and developed by the engineers from Hangzhou Linda Company, was first used as a replacement for the copper washing process in small ammonia synthesis plants ； Since the successful application of the non-isobaric alcohol alkylation process developed by Nanjing Guochang at the Feicheng Fertilizer Factory in Shandong, the C301 type high-pressure methanol synthesis catalyst has officially replaced the copper washing process used in ammonia synthesis; this catalyst is now widely utilized in the purification process for hydrogen production from ammonia synthesis. That is: the CO+CO2 concentration in the fresh gas entering the catalyst bed in C301 is 1.2~1.8%; in a state of self-heat balance without an exhaust gas recirculation unit, the CO+CO2 concentration in the gas leaving the tower is ≤300 ppm. The alcoholization process used by Hunan Ammonium Alcohol Company is also a model for replacing the copper washing process in ammonia synthesis. It was widely employed in multiple medium-pressure ammonia synthesis systems in the early years (the methanol catalyst used was C207, an alcoholization catalyst developed by the Research Institute of Nanhua Group at pressures of 1.0–1.3 MPa). In recent designs, remarkable efforts have been made both in high-pressure processes and low-pressure systems. Regarding the composition of various methanol catalysts, since they are used under different pressures and in different processes, the required catalyst activity varies; as a result, the preparation methods, the ratios of copper, zinc, and aluminum, as well as the carriers used in their production and the catalyst manufacturing processes all differ. In terms of the copper-zinc-aluminum ratio, the C307 low-pressure methanol catalyst currently has the highest copper-zinc ratio of 3:1; this is done in order to maintain a high copper content on the surface of the catalyst through the combined effect of various techniques, thereby achieving high activity. For catalysts of various models from other domestic and foreign manufacturers, their composition ratios as well as the copper-zinc ratio should not be disclosed without permission. To be continued

We have used both types of catalysts; XNC98 has a lower specific density compared to NC307. The actual performance is more or less the same – there doesn’t seem to be any difference