The advantages, disadvantages, and applicability of Luchi’s and David’s methanol technologies

Reply to 1# xunyuan119: The key difference lies in the design of their respective reactors. Lurgi uses axial reactors, which typically combine air cooling and water cooling; the large heat exchange area results in a high yield of methanol per pass, thereby reducing the circulation ratio and energy consumption. However, the pressure drop per pass is relatively high. David used a radial reactor; the small heat exchange area resulted in a low one-pass conversion rate, which necessitated the use of a high recycle ratio and thus increased consumption. Moreover, the high gas velocity inside the reactor due to the high recycle ratio required catalysts with high strength. However, its main advantage was the low one-pass pressure drop, although the issue of gas distribution needs further discussion.

Moreover, David’s process has poor local heat transfer

Judging from the design data, David is the worst synthesis technique I’ve ever seen.

Ruchi’s new-style tower can no longer be seen. But I heard that Ruchi’s tower seems to be quite large when produced in the same volume, and there are restrictions on its transportation within the country?

Those who have operated the new type of Ruchi synthesis tower, or at least those who are familiar with its design data, please share their experiences. Let’s not have only people who are guessing based on hearsay

If the shell-and-tube type is replaced with an insulated shell-and-tube type, the capacity of the tower with equal diameter increases slightly. Transporting water-cooled towers indeed presents a problem, but air-cooled towers can be manufactured separately, so there are no issues with transportation. David has four or five different tower designs, and the combinations of processes available are also diverse, not limited to radial air-cooled towers.

What is an adiabatic shell-and-tube reactor?

Reply to 8# lizhaoye: This is a methanol synthesis reactor designed by East China University of Science and Technology; it uses an adiabatic reactor in place of a gas-cooled reactor. The syngas first rises in temperature to a higher reaction temperature within the adiabatic bed reactor, and then continuous reaction and heat exchange take place in the shell-and-tube reactor, with by-product steam being generated.

What are the advantages of conducting a tubular reaction after heating the material through an adiabatic reaction? This problem has been bothering me for a long time. I’ve seen similar designs, but I can’t figure out why. What are the benefits of raising the inlet temperature of the reactant gas in the tube reactor so much?

The reason I say David is the worst I’ve ever seen is: 1. Expensive! This is a common feature of imported technologies. 2、The service is poor; no process packages in both Chinese and English are provided, questions raised are generally not answered, and the design does not take into account the owner’s investment costs. 3. Many devices have the same problem, but David designed so many of them without learning from past experiences. The same problem keeps arising. 4. Extremely high cycle ratio: with a production capacity of 900,000 tons, the designed circulation gas volume is 1.8 million tons. Compared to Casale’s 1 million tons, the designed circulation volume is only 650,000 tons. In actual use, the circulation rate in Casale is higher than the designed value. But David’s version is also quite poor. 5. David’s production process involves a high degree of recycling, which results in an extremely low content of alcohol in the output – only 5-6%, which is very low. Casali’s version has a alcohol content of 13%, and it’s said that Ruchi’s version also has a high alcohol content. David’s version is just that low. I can’t say for sure about domestic versions, but the quality of this alcohol is really disappointing for the viewers. 6. The pressure in the drum is low; compared to Cassali and Lurgi, its pressure is roughly 1 MPA lower. A lower pressure reduces the value of the steam for use. 7. David requested that the catalyst be sold as part of a bundled package. 8. The temperature is high; I’ve seen a Luzzi furnace with two sections, equipped with intermediate gas cooling. At the end of its life, the catalyst’s temperature was around 260 degrees (C302 was used, with an optimal operating temperature of 230–260°C). Steam drum pressure: 3.1–3.2. I’m afraid David won’t be able to do this.