8- The feather leaf separator is used in methanol synthesis plants to prevent liquid from entering the vent stream, thereby avoiding impacts on subsequent hydrogen production and LNG co-production processes
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This post was last edited by luoli519 on 2023-10-3 at 18:03. A friend’s methanol company is facing poor performance in its methanol production units due to the sluggish conditions in the domestic and international petrochemical markets. The hydrogen recovery from the recycle gas vent gases, along with the subsequent LNG production project, which are built alongside the methanol plant, also yield decent benefits. Recently, in response to market demand, companies have begun to reduce methanol production and increase the proportion of recycled off-gases, in order to provide more gas for downstream methanation processes used to produce LNG. However, the large flow of vent gas coming from the circulation gas pipeline posed significant problems for the subsequent scrubbers and hydrogen recovery membranes. The liquid load in the exhaust gas from the scrubber is high, and a large amount of liquid droplets are carried in the inlet gas to the hydrogen recovery membrane module, causing its efficiency to drop rapidly and leading to frequent failures. Moreover, the liquid carryover in the gas stream rich in methane and CO is severe, which enters the methanation LNG production system and leads to unstable operation of the plant system. We hope that experts in the hydrogen industry can discuss effective solutions for efficiently removing the liquid droplets contained in the inlet gas to the hydrogen recovery membrane module, in order to prevent a decline in the efficiency of this module, operational failures, and instability in the subsequent methanation process for LNG production. The easier it is to invest, the better. As we all know, the market is currently poor and funds are tight; it is necessary to consider the most reliable and low-cost investments in order to address the issue of liquid accumulation in the gas release zones. Thank you all!
Increase the height of the washing tower, thicken the foam filter mesh, and appropriately expand the area of the post-washing supersaturated heat exchanger. Furthermore, the recycle hydrogen used in methanol synthesis can be increased; this might also lead to higher methanol production.
You need to conduct an analysis first to determine what components the liquid droplets consist of, and address the root cause of why liquid droplets end up in the circulating gas. Generally, this is due to methanol as well as impurities resulting from side reactions during synthesis. It’s possible that the cooling unit isn’t performing effectively in terms of heat exchange. Instead of relying on new equipment to solve the problem, it’s better to address it at its source. Installing new equipment not only increases costs but also presents certain challenges and leads to higher expenses, which is not economical. In general, the presence of methanol can damage the hydrogen recovery membranes, resulting in a decrease in hydrogen recovery efficiency. An excessive amount of inlet gas or a high hydrogen content can also lead to a decline in hydrogen recovery efficiency; there are many possible reasons for this
It is precisely due to the current downturn in the methanol market that this company has reduced its methanol production, and instead increased the amount of recycled syngas vented to be used in LNG and hydrogen production facilities in order to achieve greater benefits. According to the original designers of the project, the existing washing towers and heat exchange equipment were designed and manufactured based on a 150% capacity expansion plan, so their processing capacity is sufficient to meet the production needs. The improvement you mentioned regarding the demister is a very pertinent suggestion. They originally installed a mesh block about 200 mm thick on top of the scrubber tower to remove foam, but the foam removal effect was poor; it should be modified, which should yield twice the result with half the effort.
There are analysis results. The off-gas passes through a scrubber tower before reaching the hydrogen recovery membrane module; the majority of the liquid contained in it is water, followed by methanol. Due to the current poor conditions in the methanol market, the company has decided to reduce production of methanol, which is not profitable, and instead increase the output of recycled gas in order to enter the LNG and hydrogen production sectors, thereby producing more profitable LNG and hydrogen products for sale. As this marine enthusiast said, an increase in the air intake volume of the hydrogen recovery membrane module leads to a higher H2 content, as well as more noticeable liquid entrainment in the airflow, which is very detrimental to the hydrogen recovery membrane module and requires urgent modification.
This post was last edited by luoli519 on 2023-10-3 at 18:04. Following discussions in an expert group meeting, it was agreed to install an efficient gas-liquid separator in front of the hydrogen recovery membrane unit in order to further remove liquid from the gas flowing into that membrane unit. Regarding the selection of efficient gas-liquid separators, the vane separator recommended in international methanol synthesis process packages in recent years is employed; this separator offers significant advantages over traditional separators in terms of quantitative separation efficiency, operational stability, resistance to clogging, operational flexibility, and operating pressure drop. For the technical parameters of the feather leaf separator, please find more information on this HaiChuan Chemicals forum.
This post was last edited by luoli519 on 2023-9-26 at 16:21. Additionally, the following professional discussion posts published by NOVEL Nuowei Energy Technology Company on the HaiChuan Chemical Forum are listed here for everyone to use as links to join the discussions: 13. Discussion on improvements to the inlet devices of cyclone separators in gas-solid separation applications; please visit http://bbs.hcbbs.com/thread-1614524-1-1.html to participate in the discussion. 14. Regarding the issues arising from the use of swirl tube/swirl plate demisters in the wet flue gas desulfurization process for boilers, please visit http://bbs.hcbbs.com/thread-1599605-1-1.html to participate in the discussion.
Is the liquid entrained in your gas the amine solution used to wash acidic gases? If that’s the case, then there is a problem with your amine solution; foaming of the amine solution leads to a high amount of liquid carried in the gas stream. To prevent foaming, one approach is to test the composition ratio of the amine solution and adjust it to a proper ratio ； 2. If the amine solution is contaminated, it is recommended to clean the filter and increase the filtration return flow rate ； 3. Increase the temperature of the amine solution
Also, since you have increased the air intake volume, the liquid flow rate in the scrubber tower must also increase
This post was last edited by luoli519 on 2023-9-26 at 16:22. It seems that this marine enthusiast is not very familiar with the H2 and LNG co-production process for the comprehensive utilization of methanol cycle off-gases. 1. Since the feed gas to the methanol synthesis unit contains a certain amount of inert gases, side reactions during the synthesis process result in the formation of hydrocarbons with carbon counts of 2 or more. Repeated cycles of the feed gas lead to the accumulation of these inert gases and hydrocarbons; it is therefore necessary to vent them in proportion in order to reduce their concentration in the reaction system and ensure that the synthesis process can proceed normally. 2. The recycle vent gas from the methanol synthesis unit contains significant amounts of methanol, in both saturated gaseous form and as liquid droplets; it is necessary to absorb these substantial amounts of methanol using a compatible scrubber tower, in order to prevent methanol and other liquid organic substances from damaging the subsequent hydrogen production membrane modules. Wash towers used to absorb methanol and C2+ hydrocarbons will more or less experience gas-liquid entrainment, with higher gas velocities leading to more severe entrainment. Therefore, the scrubber tower must employ a vane separator to efficiently remove foam and mist from the gas stream exiting the tower. 3. The outlet gas stream from the scrubber tower, which is used to absorb methanol and C2+ hydrocarbons, can cause damage to the hydrogen production membrane stack due to foam removal issues and temperature differences during transportation, as the liquid methanol and C2+ hydrocarbons carried in this stream may harm the membranes. Therefore, a vane separator must be used for the inlet air to the hydrogen production membrane module to effectively remove foam from it. 4. The H2 separated by the hydrogen production membrane unit is reused as a component of the methanol synthesis gas, while the methane and C2+ hydrocarbons separated by the same unit proceed to the subsequent LNG production unit. 5. Regarding the vane separation technology equipment involved in the LNG production unit,
The explanation was very comprehensive; I learned a lot. It was me who misunderstood