Special guide to coal-based ethylene glycol

What are the requirements for CO gas regarding downstream ethylene glycol? Purity and temperature?

Do you mean to remove CO2, H2S, CS2, COS, H2, and N2 from the syngas using a cryogenic box? Or just release carbon dioxide and sulfides? Carbon monoxide has a melting point of -199°C and a boiling point of -191.5°C; these conditions are quite stringent

Placing this topic under the gasification section seems a bit off. Just talk casually. It is the separation and supply of raw materials for ethylene glycol, though. However, the CO cryogenic tank is not related to the gasification personnel, and it is generally not under the responsibility of the personnel who operate ethylene glycol either; therefore, it is more appropriate to place this question in the purification section. The CO cryogenic tank is connected in series after the low methane stage, so it can be assumed that the gas components are only CO/H2/N2 and methane. Its function is similar to that of a liquid nitrogen washing chamber, but since the liquid nitrogen washing process is used to remove trace amounts of methane and CO from the gas, a single washing tower within the chamber is sufficient. The CO cryogenic box is used in the distillation and separation process, which makes it more complex. Depending on the requirements of various ethylene glycol process packages as well as the design choices of the cryogenic box manufacturers, there may be two or three towers inside such boxes; among the manufacturers used in China are Linde, Air Liquide, and Hangyang. Its separation principle is exactly the same as that of air separation. It involves expansion or throttling refrigeration; after CO is liquefied, distillation can be used to separate it into three products with purities of over 99%. This is generally the required quality standard for CO. In fact, the carbonylation catalyst is sensitive to H2 and can become reversibly poisoned, while N2 and methane do not pose much problem. Nitrogen is also added during the reaction as a safety measure. Unlike air separation, both oxygen and nitrogen can be liquefied; after distillation and separation, pure oxygen and nitrogen can be obtained simultaneously in the cryogenic tank. In contrast, hydrogen does not liquefy in the CO cryogenic tank, so impurities such as CO present in it must be purified using pressure swing adsorption. The CO cryogenic box also has two processes: in the case of purified syngas containing a high amount of methane, it is beneficial to first liquefy the methane; this facilitates the absorption of CO followed by distillation for separation, resulting in a higher yield of CO ； Of course, such conditions do not exist in a fluidized bed. Secondly, direct separation of H2 and CO results in low yields; however, by using PSA, the gas released after hydrogen extraction can be pressurized and sent back to the cold box, thus avoiding waste – only increased energy consumption occurs. CO is generally extracted from the top of the rear tower; since the light components have already been removed from the top of the front separation tower, the purity of CO is very high. Linde’s process in China was originally adapted directly from the CO production units used for acetic acid, and it seems that energy is not being utilized efficiently. The one made by Hangyang is a bit more complex but should have good efficiency; it’s quite practical for use in vacuum conditions. Of course, for the cryogenic purification of gases in volumes of 100,000 cubic meters, domestic technology is more than sufficient. In these past two years, there has been more information available on cold boxes; those who want to learn more can search for it on their own.

Nanjing Dunxian Chemical Technology Co., Ltd. has developed large-scale radial serpentine tube carbonylation reactors and radial spherical-chamber serpentine tube hydrogenation reactors that replace the traditional tubular carbonylation and hydrogenation reactors. For a production capacity of 20×104 t EG/a, these reactors not only enable savings of 1,120 tons of steel and 67.2 million yuan in investment costs, but also feature low catalyst bed resistance; the catalyst beds are isothermal in nature. The gas flow pattern in the carbonylation reactor’s catalyst bed is from inside to outside, while in the hydrogenation reactor’s catalyst bed it is from outside to inside. This design helps to control the formation of by-products at the source of the carbonylation and hydrogenation reactions, further reducing the consumption of raw gas and the steam required by distillation units. As a result, this can generate an annual economic benefit of 85.214 million yuan for the enterprise. The large-scale radial coil-type carbonylation reactor and radial spherical-chamber coil-type hydrogenation reactor have been successfully developed, solving the challenge of scaling up ethylene glycol production facilities. Just like nitric acid reduction technology and ethylene glycol purification technology, these innovations will undoubtedly contribute to improving the scale of ethylene glycol production facilities in China, reducing engineering costs, lowering operational energy consumption, and further enhancing product quality. Friends who are interested can contact us (Manager Li: 18851611090)

Do the experts have any process documentation? Please send it to 616408951@QQ. com, thanks

Do the experts have any technical documentation? Please send it to 1599747728@qq.com. Thank you!

So many years have passed; now I’ll answer this question myself. The result is positive; there’s no problem.