The following is based on the website pages and / or brochures of various OEMs. It has been compiled to give a snapshot of key valve applications that are typically associated with various stages of the steam cracking process; it does not pretend to be an exhaustive account. Feedstock: Control valves are used to regulate the flow of feedstock into the furnace. A typical plant requires multiple control valves arranged in parallel. The feedstock control valve has to function reliably across a wide range of flow rates, given the need to accommodate start-up, commissioning, normal operation and shutdown of furnaces for maintenance. Accuracy and stability during normal operation are key factors, as excessive fluctuations in the feedstock flow can impact downstream processes. Fire- π www. valve-world. net Valve World June 2025
Steam crackers form an essential part of our industrial landscape. For decades, they have been used to convert larger or saturated hydrocarbons into versatile basic materials such as ethene, which in turn is the basis for omnipresent plastics like polythene. Desk research indicates the key role that valves fill in a surprising number and variety of applications.
Petrochemicals
Valves essential for safe, reliable and efficient steam cracking
By KCI Editorial
Basic principles
The basic principles behind a steam cracker are readily explained. The feedstock, such as ethane, naphtha, etc is mixed with high temperature steam and heated in a furnace. Under these conditions a chemical reaction takes place whereby the feedstock molecules are‘ cracked’ to form smaller molecules and / or unsaturated molecules. The chemicals thus produced, such as ethene, form the starting point for highly useful products like polythene. The devil, of course, is in the detail. To start with, the reaction requires temperatures typically between 800 ° C to 1100 ° C. Moreover, the socalled residence time in the furnace is just a few milliseconds. The cracked gas then requires quenching to stop the cracking process. Without quenching, the cracking process could continue, ultimately breaking all the hydrocarbons down completely to their basic elements – carbon and hydrogen. The gas next has to be compressed before being passed through an acid gas absorber, a wash tower, dryer beds and various separation stages to isolate all the cracked products. In addition, the cracking processes typically causes a slow build-up of a hard layer of coke( a form of carbon) on surfaces inside the reactor.
Image credit: BASF SE.
This impairs reactor efficiency. Furnaces are therefore typically de-coked every few months, by flushing them with steam. This converts the coke to carbon monoxide and carbon dioxide gases. In short, steam cracking facilities are therefore complex systems, in which various types of highperformance valves are required.
Valve overview
The following is based on the website pages and / or brochures of various OEMs. It has been compiled to give a snapshot of key valve applications that are typically associated with various stages of the steam cracking process; it does not pretend to be an exhaustive account. Feedstock: Control valves are used to regulate the flow of feedstock into the furnace. A typical plant requires multiple control valves arranged in parallel. The feedstock control valve has to function reliably across a wide range of flow rates, given the need to accommodate start-up, commissioning, normal operation and shutdown of furnaces for maintenance. Accuracy and stability during normal operation are key factors, as excessive fluctuations in the feedstock flow can impact downstream processes. Fire- π www. valve-world. net Valve World June 2025
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