Lurgi’s methanol synthesis technology
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The characteristics of Lurgi’s coal-to-methanol synthesis technology, as I understand them, are as follows: 1. There is no guard bed. Lurgi does not require a guard bed for its methanol synthesis process; it seems that a total sulfur content of less than 0.1 ppm is sufficient. It’s unclear whether this is due to their confidence in the low-temperature methanol washing purification technology (Lurgi being one of the original developers of this technology) or because the catalysts produced by Southern Chemical have excellent performance. This is different from other manufacturers of methanol synthesis technologies. 2. The amount of catalyst used in methanol synthesis is moderate. The SUDE-CHEMIE catalysts from Southern Chemical must be used, and this represents an exclusive partnership. As a result, if Lurgi fails to secure a project, it becomes very difficult for these catalysts to enter the Chinese market. Conversely, does this facilitate the sales of JMC and TOPSOE catalysts abroad in China? 3. The methanol concentration at the outlet of a single methanol synthesis tower using this technology is around 13–14% V, with a ratio of recycled gas to fresh gas of about 2. This is different from what some people claim, namely an outlet methanol concentration of 17% and a ratio of 2.5. It’s important not to confuse gas-cooled synthesis towers with water-cooled (steam-producing) synthesis towers. Only when two towers, one water-cooled and one gas-cooled, are connected in series can an outlet methanol concentration of 17% be achieved. However, this comes at the cost of reduced steam production, higher investment costs, and increased pressure losses. Given the rising cost of energy, is this really worthwhile? 4. Lurgi’s water-cooled (steam-producing) synthesis towers can have a catalyst capacity of up to 100 m3, as seen in the 2000 MTPD natural gas-to-methanol plant in Hainan. But only Lurgi is capable of implementing such systems, and they can only be used in coastal areas (as transportation to inland areas is not feasible). Therefore, for inland methanol plants with capacities exceeding 2000 MTPD, using Lurgi’s towers proves to be challenging (not to mention using domestically produced towers similar to Lurgi’s). 5. It’s puzzling that large domestic methanol plants still use water-cooled towers in combination with Lurgi’s gas-cooled towers, even though problems have arisen with the latter in Trinidad. 6. Lurgi’s methanol synthesis technology is classic, but the reaction rates associated with it are becoming slower. Whether this is related to Lurgi’s acquisition by Air Liquide or simply a lack of interest in the Chinese market, it’s possible that this technology will eventually become obsolete.
1. Purification technology in our country is also highly developed nowadays, especially dry desulfurization and dechlorination. Coupled with the widespread use of centrifugal compressors, the Lurgi process has found extensive application in both polyol and monohydric alcohol production processes. Of course, this is related to the fact that the scale of methanol production in our country is generally below 300,000 units per plant. At the same time, the catalysts used in our country can also last for more than two years; of course, the original poster is an authority on this topic, so I won’t say much further. 2. For the water-cooled and air-cooled combined tower, is it true that only one plant in China is currently implementing this design? Considering the compression ratio and energy consumption, no real data are available regarding its air-cooling section; therefore, an optimistic attitude is held toward its performance, with the hope that it will deliver good results. However, I don’t think a high alcohol content necessarily means it’s a good thing ； 3. The Luchy synthesis technology has been popular in China for many years; it does have its advantages. Of course, limitations related to the scaling up of equipment mean that a single unit cannot be very large. I hope those who have seen this topic will share the problems they have encountered with this type of processing, as well as any good practices that are worth promoting, so that we can all learn from them and improve together ； 4. I hope the original poster can initiate discussions on the remaining typical methanol production processes, building on Topso and Luchy processes – as a gift for all those working in the field of synthesis for the New Year, hehe!
Different patent holders employ different levels of effort and strategies in promoting their technologies; some regularly attend various conferences, publish articles, and sponsor events, which helps to increase their visibility and makes it easier for others to become aware of them. On the other hand, some patent holders are less active in these areas, which not only results in them remaining unknown but can also lead to misunderstandings.
This process is still very popular in our country today, and it certainly has notable advantages: 1. It is simple to operate, as control mainly involves the pressure of the steam drum and the space velocity； 2. It operates stably; if gas purification is done properly, the catalyst will definitely function fine for two years ； 3. It is particularly suitable for the methanol-amine process, as in methanol production the methanol load is low; systems are generally designed with a minimum energy consumption ratio of 1:9 between methanol and ammonia. Thus, it primarily serves a refining function while also helping to maintain thermal balance. So even if we calculate based on a large-scale production of 300,000 tons of ammonia, the methanol load will not exceed 40,000 tons – isn’t that a piece of cake for Lurgi? Haha
Personal opinion: 1. As a leading global developer of technologies for low-pressure methanol synthesis, Luchi’s design and configuration for methanol synthesis towers still represent the standard for large-scale methanol production facilities worldwide. To the best of my knowledge, most of the methanol plants in China with an annual production capacity of 500,000 tons (per unit) that are currently under construction or already in operation adopt its design concepts. 2. Main problems in Luzzi’s methanol synthesis: · The equipment is large, which limits its transportation, especially in projects with a daily methanol production of over 3,000 tons. ·The equipment resistance is too high. ·There is a large temperature difference between water cooling and air cooling. 3. There is no risk associated with Luchi’s technology in the project for an annual methanol production capacity of 500,000 tons. The 600,000 tons per year methanol production facility of Sinochem Chemical uses the Lurgi technology; the plant boasts high reliability. Since its commissioning one year and two months ago, it has only experienced a brief shutdown due to a shortage of feed gas, and it has been able to operate steadily for long periods while achieving its designed capacity. 4. Under the current circumstances, given that investment is not considered, adopting Lurgi methanol synthesis towers (with a dual-tower configuration) for the project with an annual production capacity of 500,000 tons of methanol is a prudent choice.
For Luchita, when catalyst use progresses to later stages, what level will the pressure in the steam drum be controlled at? For low-pressure synthesis, the pressure will definitely rise at this point; how can an appropriate pressure be controlled? Furthermore, what are the obvious signs of declining catalyst activity? Should we control the pressure in the drum at around 3.0 MP from the early stages of production?
Now there is a question: regarding the Luchy process, how is equilibrium achieved for the reaction of gases inside the tubes? How can the one-way conversion rate be improved? If you want to increase the output per trip, what are some reasonable ways to do that?
Could the original poster explain what the differences are between this process and Anchun Company’s alcohol tower? I think their techniques and operations are basically the same now.
The discussions on the 10th floor did not go beyond the framework related to methanol synthesis using natural gas. Personally, I think it’s pointless and unnecessary to compare Luqi with Ammonium Methanol Company. Have you ever wondered why the methanol synthesis tower designed by Luqi in Hainan for a capacity of 2000 MTPD is a single-tower design, while the methanol synthesis towers in China for a capacity of 1500 MTPD use a two-tower design? If we set investment aside, it’s possible to increase the capacity by adding more synthesis circuits and towers, but there is no technological advancement in this regard. If there’s no technological progress and the investment is high, then why go ahead with such projects? As a rough comparison, if a methanol synthesis tower using natural gas can produce 2000 tons per day, the same tower using coal can produce 4000 tons per day. This is why the catalyst volume used in Hainan (for a 2000 MTPD natural gas-based plant) is around 100 cubic meters, whereas the catalyst volume used in Yankuang Yulin (for a 2000 MTPD coal-based plant) is around 50 cubic meters.
Everyone is also welcome to participate in the discussions on the following post: Selection of Methanol Synthesis Reactors with a Capacity of Millions of Tons per Year http://bbs.hcbbs.com/thread-42199-1-1.html
The catalyst loading in Hainan is approximately 100 cubic meters; it’s absolutely impossible for a single water-cooled synthesis tower to have a diameter of 2.4 meters. If the diameter is estimated to be over 5 meters, it is not called an INTERCHANGER either. The one called interchanger is E-02002, which is a gas-gas heat exchanger. The reactor’s location code is R-02001; it is called the Water Cooled Methanol Reactor
Thank you so much! But there are still some doubts; I heard that a catalyst is installed inside the interchanger. Is it a water-cooled unit with an interchanger connected in series?
Owner, you said that \"it’s puzzling that large methanol plants in China still use air-cooled Ruhr-type synthesis towers, even when there are problems with such towers in Trinidad.\" What exactly went wrong with those towers? Could you provide more details?
The Lurgi methanol synthesis reactor is a tubular reactor with a tubular heat exchange format, and the flow direction is entirely axial. More complex, with higher investment costs. The equipment manufacturing cycle is longer than that of other reactors, and the catalyst used cannot be removed. The methanol synthesizer at East China University of Science and Technology is of good quality, requires low investment, has a short equipment manufacturing cycle, and the catalyst can be removed easily.
Air cooling makes it difficult to believe in its stability. Luchi’s reactors are indeed good, and there is no need to use southern catalysts at the moment; however, transportation within the country and the cost of the reactors are indeed major issues. It is recommended to give more attention to Topso and Cassali
If you had some knowledge of Lurgi’s methanol synthesis reactors and those used by East China University of Science and Technology, you wouldn’t say such things.
As far as I know, the first application of Cassali’s IMC was in Russian gas-cooled methanol synthesis towers; operation began in 2002 and the catalyst was replaced in 2007. If temperature control is difficult and there are large temperature differences within the same plane, it is doubtful whether the catalyst can be used for such a long time. It is recommended to get in touch with Cassali on the 22nd floor.
Why is the crude methanol inlet pipe of the low-pressure methanol flash tank inserted below the liquid level? Can crude methanol be placed above the liquid surface? What is the difference between crude methanol entering below the liquid level and above the liquid level? In most flash tanks, the liquid inlet pipes are located above the liquid level, while those of low-pressure flash tanks are below the liquid level. What is special about this? Please provide guidance from technical experts!
Lurgi coal pulverization pressurized gasification is the earliest industrialized coal pressurized gasification technology in the world, and it is widely used both domestically and internationally. Its main features are as follows: a It can be used for gasifying low-quality coal with high moisture and high ash content; b due to counter-current gasification, oxygen and coal consumption is low, and the gasification efficiency and coal conversion rate (including by-products) are higher than those of other methods. c It produces by-products such as tar and phenol, which can be utilized comprehensively. Coal with a high oil content accounts for about 5–6% of total coal volume, and can be converted into tar products. d has high operational flexibility, stable performance, and mature technology. The composition of coal gas is complex, containing a high amount of methane; it requires significant amounts of steam. In the raw coal gas, CO+H2 accounts for only about 60%, while the methane content ranges from 7 to 10%. The raw gas produced by Lurgi’s pressurized gasification technology contains a high level of methane, which makes it suitable for use as city gas; however, if it is to be used as a feed gas for synthesis, methane conversion units are required, resulting in a more complex process ； Due to fixed-bed counter-current gasification, the crude gas contains high levels of tar, phenols, etc., which necessitates the use of systems for purifying these substances as well as wastewater treatment systems. The Luchi gasification technology has requirements regarding parameters such as the particle size, cohesion, and ash fusion point of the feedstock. With mechanized coal mining being used today, large pieces of coal are scarce; therefore, it is necessary to consider integrating this technology with power plants in order to make rational use of the coal. In short, for the production of methanol synthesis gas, Luhui pressurized gasification does not have the advantages of producing city gas or methanol as a co-product of city gas production.
A pressure difference of 5 MPa to 0.4 MPa, if it occurs above the liquid level, is sufficient to cause methanol to flash rapidly and be carried into the gas line, and the liquid level in the flash tank also becomes very unstable. This problem can be completely solved below the liquid surface.
The inlet pipe below the liquid level can reduce the loss of methanol during the flashing process.