【Ethane Steam Cracking】What are the special material pipes used in ethane steam cracking?
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Besides regular austenitic stainless steels and pipes made of low-carbon and low-alloy steels, what other high-alloy pipes are there? Are there pipes made of nickel-based alloys?
Are there high-pressure, high-alloy pipes available?
What pipes are there for the output from the pyrolysis furnace?
On April 3, the pressure testing of SS-001# pressure testing bundle for the ultra-high pressure steam pipeline of the 800,000 tons per year ethylene plant in the Changqing Ethane to Ethylene project, constructed by Huanqiu Liu Jian Company, was successfully completed. This pipeline represents the one with the highest pressure testing requirements and the greatest welding challenges among all the pipelines in this project; it took 30 hours from the start of water injection to the completion of the pressure testing. Its completion marks the entry of the pressure testing of the project’s process pipelines into the final stage, creating favorable conditions for subsequent tasks such as steam testing and the heating up of the cracking furnace. The process pipes of the ultra-high pressure steam system that were subjected to pressure testing this time have a maximum diameter of 457.2 millimeters and a maximum wall thickness of 34.93 millimeters; their main material is P91, and the testing pressure reached as high as 33.1 megapascals. The entire pressure testing process system starts from the ethylene cracking furnace, passes through the pipe galleries in front of the furnace, the main pipe gallery, and the pipe galleries in the compression area, and finally reaches the cracking gas compressor; the total length of the main pipeline is 856 meters. For the first time, the project utilized the company’s self-developed fully automatic welding process for heat-resistant steel pipes to prefabricate the pipe sections, thereby ensuring high welding quality.
SH T 3423-2011 Technical specifications for cast high-alloy furnace tubes and fittings for petrochemical tubular furnaces; SH T 3422-2011 Technical standards for nail-type tubes used in petrochemical tubular furnaces; GB T 51175-2016 Engineering specifications for flame heating furnaces in oil refining plants. Look for them there
The furnace tubes of the cracking furnace are made of nickel-based alloys, but they are generally welded on-site to the gold-welded joints of the waste boiler. Argon shielding is a problem. The main steam pipeline is P91, while the branches can use P22. Then there are some 2,500-pound thick-walled 316 pipes.
The photo should show the third floor of the platform; the pipes appear to be main steam pipes.