Methanol Weekly Topic: How can methanol production increase reaction yield? 2015.08.03--08.10

A brief analysis of how to improve the recovery rate in methanol distillation. The concept of distillation recovery rate is the ratio of the amount of pure methanol produced to the amount of crude methanol consumed to produce that pure methanol, multiplied by 100%. As can be seen from the above equation, when the amount of crude methanol consumed is fixed, the recovery rate can only be increased by raising the amount of pure methanol produced. Through analysis and summary, several factors affecting methanol distillation have been identified, in order to explore ways to improve the recovery rate of methanol during distillation. First, eliminate leaks, spills, and losses. The methanol distillation process involves mass and heat transfer between the liquid and vapor phases, under high pressure and temperature conditions. If there is leakage of materials, it will reduce the amount of distillate, thereby affecting production; therefore, it is necessary to eliminate such leaks. Second, improve the efficiency of the methanol cooler. Before being extracted, the finished product generally passes through a top condenser for cooling, where it is converted from methanol vapor into a vapor-liquid mixture, which is then collected in the methanol reflux tank and pumped back into the tower under pressure for further distillation. At this point, increasing the pressure of the circulating water and raising its flow rate can increase the steam cooling rate per pass, facilitating a better separation of liquid methanol and thus increasing the yield of pure methanol. Third, minimize the extraction of by-products as much as possible. Methanol synthesis is a reaction of organic compounds, and side reactions generate numerous by-products, including diethyl ether, fusel oils, and CH compounds with varying boiling points. Many of the components in these products have a structure similar to that of methanol and are soluble in methanol. If the methanol meets the quality standards, reducing the amount of by-products extracted allows them to dissolve in methanol and be obtained as a product, which also reduces the loss of methanol that occurs along with the by-products, thereby increasing production. Fourth, increase the bottom temperature as much as possible while ensuring product quality. In methanol distillation, crude methanol is fed in at the feed plate, and it flows down through the various plates together with the reflux liquid from the top of the tower; each plate retains a certain thickness of liquid ； The pipeline steam enters the reboiler from the bottom of the tower, enabling the methanol vapor to rise gradually and undergo mass and heat transfer with the liquid on the tray. Throughout the process, the light components move upward while the heavy components move downward; after sufficient numbers of tray layers, the product can be obtained at the appropriate tray. Therefore, by increasing the temperature at the bottom of the tower, more heavier components can be added to the rising light components; in other words, it prevents the light components, such as methanol, from being removed along with the wastewater at the bottom of the tower and thus wasted. This approach can also increase production. Fifthly, careful operation and extensive experience are also important factors in ensuring the methanol recovery rate. As is well known, chemical production is a task that relies heavily on experience; only by performing various operations with great skill can the work be done properly. In distillation operations, it is necessary to maintain precise control in order to avoid unnecessary waste; for example, the waste resulting from excessive venting at the top of the pre-tower due to high steam pressure, or the waste caused by a decrease in the temperature of the atmospheric tower due to low steam pressure, which leads to methanol being discharged along with wastewater. By avoiding these issues and making timely and accurate judgments regarding operating conditions, it is possible to keep the operations in their optimal state, which in turn results in the highest yield of pure methanol and thus a high methanol recovery rate. In summary, improving the recovery rate of methanol is a systematic effort that requires careful operation, strict control over product quality, the accumulation of experience, and efforts to enhance equipment efficiency as well as develop new processing methods. It is a comprehensive approach aimed at achieving maximum benefits while simultaneously reducing energy consumption and emissions

Not bad, I’ve learned it! ! ! ! ! ! ! ! ! ! ! ! !

In terms of pressure processes, the partial pressures of carbon monoxide and hydrogen are the driving forces behind the formation of the product. From both thermodynamic and kinetic perspectives, 215–290 is the optimal temperature for the bed layer; higher temperatures facilitate molecular collisions and bonding, while lower temperatures help maintain the catalyst’s performance over time. The hydrogen-to-carbon ratio: for the feed gas, a value of 2.05–2.15 is required according to the process specifications; for syngas, a range of 3.5 to 10 is considered an appropriate value for optimal operation. The lower the content of inert gases, the better, as they reduce the partial pressure of the useful gases, and certain substances continuously adsorb and desorb on the catalyst surface, affecting its performance. Generally, the inert gas content in the off-gas should be kept below 10%. High air velocity is required; the power for reciprocating machines is generally between 7,000 and 11,000, while that for centrifugal machines ranges from 12,000 to 18,000. A higher air velocity results in faster gas flow, which increases the chances of contact with the catalyst and thus boosts the output per unit of time. Catalyst activity: A catalyst serves as a platform for carrying out reactions in synthetic processes. The larger the active surface area, the better the reaction proceeds; it only affects the rate of reaction, not the equilibrium. It requires a large specific surface area, as well as good adsorption/desorption properties and mechanical strength. Synthesis generally involves kinetic energy consumption and heat consumption; a high space velocity and high pressure facilitate the production of more methanol per unit of catalyst, but kinetic energy consumption will definitely increase. The main goal in terms of cold consumption is to achieve cooling and separation in the downstream system, thereby maximizing the recovery of heat from that system and transferring it to the synthesis boiler system to produce high-quality steam. This approach allows for less use of cold energy and enables the complete condensation and separation of methanol.

1. Temperature must be strictly controlled； 2. Ensure stable reflux ； 3. Stable temperature after cooling, with reduced fluctuations ； 4. The feed temperature and feed rate are stable.