Equipment bottleneck issues in silver-based formaldehyde processes
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In the silver-based formaldehyde process, most current silver-based processes use stainless steel oxidizers; a copper mesh is placed on the tube sheet, with a catalyst loaded on it； Such an oxidizer structure has significant problems; oxidizers generally need to be replaced after about three years of use. But what are the reasons that cause such issues? I’ll share here some of my simple opinions; they may be immature, so feel free to give your feedback! 1. It is determined by the design of the process; the silver-based process requires approximately 30 minutes for completion (some companies prefer even shorter times). The catalyst temperature needs to be raised from around 100 degrees to about 550 degrees. Due to the long ignition time, the catalyst tends to agglomerate, which leads to high consumption costs, and dealing with unprocessed formaldehyde becomes problematic. 2. A long ignition time is unsafe; explosions can occur due to changes in the oxygen-alcohol ratio! 3. Issues with the design of the oxidizer: if a bayonet-type heat exchanger is used, it will **extend the equipment’s service life** ； A formaldehyde factory once built such a heat exchanger on its own, and it lasted for 7 or 8 years. Heat exchangers in the bayonet format are already in use in the American-Holland ammonia synthesis process, which operates under even more severe conditions. Of course, the investment in equipment will be higher! 4. The current silver-based formaldehyde process fails to achieve a good integration of production, academia, and research ； Basically, it’s just a few companies that are involved in this, and the short service life of the oxidizers contributes to their increased profits. 5. Many companies do not make an effort to improve their manufacturing processes; everyone is looking for quick profits ； Instead, they engage in price wars and cut employees’ salaries in order to ensure the company’s profits. 6. Should one consider learning some of the methods used in design and operation within large-scale chemical engineering for the formaldehyde production process? ； Rules that must be followed during the heating and cooling of the equipment should be fully considered in the design to create the necessary conditions ； Of course, this is another issue related to costs! Moreover, ordinary enterprises do not possess the utility infrastructure required for large-scale chemical production (such as steam at pressures above 4.0 MPA). Domestic formaldehyde manufacturers generally build their own plants and handle all their utility needs internally. That’s all for now!
The oxidizer is a key device in formaldehyde production. Its reaction is similar to that of ammonia oxidation, but after formaldehyde is produced via catalysis, it must be cooled immediately to below 300 degrees to prevent its decomposition. The formaldehyde reactor has been improved many times; we invite all fellow sailors to share any new ideas for discussion.
This post was last edited by zsj2089 on 2012-4-30 at 12:38. It’s possible that the original poster is not very familiar with the formaldehyde industry; the durability of oxidation furnaces depends on various factors such as material quality, water quality, pressure, and temperature. Many equipment manufacturers in China are also working on new types of oxidation furnaces. Since I started working in the formaldehyde industry, I have seen at least five generations of such furnaces. Promoting reactions and reducing material consumption are the goals pursued by those working in the field of formaldehyde. The claim that a short lifespan of oxidation furnaces can increase the profits of equipment manufacturers is somewhat extreme. Think about it: if the oxidation furnace I have you make isn’t durable, will I still turn to you for the next one?
The current oxidation furnaces shouldn’t last three years either; it must be a quality issue on the part of the manufacturer – they used substandard materials. The nickel content in the tube sheets and heat exchange tubes is insufficient. There are various types of stainless steel, and 304 stainless steel is fine for other applications, but it’s not suitable for use as tube sheets or heat exchange tubes. Ours have been in use for five years now without any problems
The damage to the oxidizer is mainly caused by cracks in the tube sheet, which is related to the rate of temperature change; therefore, it is necessary to ensure a smooth temperature rise and fall during operation, and the material used for the tube sheet should also be improved.
Our factory has been using oxidizers for only a short time, so we don’t have any practical experience with them. But it’s not necessary to replace the equipment after just 3 years, as people say
It is generally around 5 years; if there is no water shortage and care is taken during each heating and cooling cycle, the lifespan may be extended.
The typical service life of such equipment is 20 years; our formaldehyde oxidizer has been in use for two years without any problems
The service life of a formaldehyde oxidizer is determined by factors such as the material used, water quality, pressure, and temperature. Under normal conditions, it can be used for three to five years; generally, there are no issues with the tube sheet, but the heat exchange tubes may break, and in such cases it is sufficient to replace those tubes
Which domestic manufacturers offer complete sets of formaldehyde production equipment are the best? We mainly consider the equipment’s service life and product consumption. Thank you!
It seems that the person on the 1st floor has worked in large companies, or at least has been in contact with them, but I don’t entirely agree with some of their views. Some large domestic enterprises acquired oxidizers produced in Taiwan; it seemed like a legitimate approach, with each 60,000-ton oxidizer costing 3 million yuan, yet they became unusable within less than 4 years. In China, similar affordable equipment costs only 500,000 yuan, and it can still be used for 5-6 years. In one country, the development of formaldehyde production technologies is the fastest, as the formaldehyde industry is dominated by domestic enterprises, which account for 80% of it. Process technology is advancing very rapidly. The domestic methanol cycle method can achieve a consumption of 435 kg, with 720 kg of steam being produced as a by-product along with 37% formaldehyde, and the pressure can reach 7 kilograms. I have the design drawings for a 60,000-ton oxidizer (with by-product steam pressure of 7 kilograms); please contact 18631552938