Ethylene feedstock

Ethane, propane, C4, light hydrocarbons from oil fields, LPG, dewaxed oil, naphtha, hydrogenation tail oil, extractive distillate oil, and light diesel are all conventional raw materials for ethylene production; they can be cracked separately or together using a combination of these materials. LPG with a high content of olefins, such as cokerized LPG and catalytic LPG, tends to cause coking in the furnace tubes during the cracking process due to the high levels of olefins present; this affects the production cycle and the yield of ethylene. Therefore, it is necessary to first hydrogenate the olefins to convert them into alkanes, before feeding them into the cracking furnace for cracking.

Are there any separate LPG hydrogenation units in the country?

How is integration of refining and chemical processing carried out in China? Is the hydrogenation of olefins and LPG to produce ethylene done, or is it sold as a commodity?

Now, the ethylene content in catalytic cracking dry gas has also attracted attention, as it holds great value for recovery and utilization. One method is separate recovery: after the catalytic dry gas is concentrated through pressure swing adsorption and purified to remove impurities, it is fed directly into the deep cooling separation unit of the ethylene plant to separate ethylene and ethane; Lanzhou Petrochemical has such a facility in place. Another process that can be directly synthesized for use is the catalytic dry gas-to-ethylbenzene process, jointly developed by the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences and the Second Oil Plant of China National Petroleum Corporation in Fushun. This process has passed **-level appraisal, and a patent has been applied for; its ethylene recovery rate is very high. In Fushun, China, there is already a facility of this type with an annual production capacity of 60,000 tons of ethylbenzene.

When the olefin content in LPG is high, coking tends to occur during ethylene cracking. This is a problem with LPG from coking and catalytic cracking. Hydrogen saturation can solve this problem, but the hydrogen source and cost are issues. But there have also been cases in China where production continued despite a shortage of ethylene raw material; it seems this happened in Maoming.

For LPG containing olefins, the olefins need to be separated first; using them as ethylene feedstock is a waste. Do you know how much per ton acrylic, butylene, and styrene cost? Currently, catalysis is being used in technologies to increase propylene production. We’ve catalyzed all the propylene into polyethylene. This post was last edited by net2002163 on 2008-6-19 22:00]