Plant #1 > NC
The naphtha cracking plant, which is called the flower of the petrochemical industry, produces ethylene and propylene as the major products and hydrogen, metal, C-fraction, PG, C3LPG, C4LPG and PFO as byproducts by thermal cracking the raw material naphtha at ultra-high temperatures of over 1,200℃. Construction of the plant was completed in 1992 by the technology of Lummus Crest (CB&I) Corporation, and it currently has an annual production capacity of 1 million tons of ethylene and 0.52 million tons of propylene. The major products ethylene and propylene are used as primary raw materials for polymer plants. And for the byproducts, hydrogen is used as raw material for the hydrogenation and reaction equipment of other plants, methane as fuel for the thermal cracking process, propane and butane as the plant’s own fuel and the surplus is sold to the market. Also, products with C5 composition and above are used as raw materials for BTX plants, and heavy distillate products such as PFO are used as the plant’s own boiler fuel.
■ Production process
01 Thermal Cracking Process
The process involves thermal cracking of the raw material naphtha at high temperature of over 1000 ℃ and separating it into hydrocarbon compounds with various components. Our cracker consists of 9 liquid crackers and 1 ethane cracker. The hydrogen, methane, and C4LPG produced from the process are used as fuel.
02 02 Quenching Process
In this process, the thermally cracked substance that is issued from the cracker is quenched, primary-cooled with quench oil, and the heavy distillate (thermally cracked fuel oil and gas oil) is separated to prevent the formation of coke and tar through polymerization. The thermally cracked gasoline is produced after the second cooling at the quench tower, the fuel for BTX plant is supplied and the separated light cracked gas is introduced to the compression process.
03 Compression Process
This process involves compressing up to 38KG by cracked gas compressor since the separation of components from the substance coming from the cracker is economically possible only under high pressure. Between stage 3 and stage 4 is a caustic tower that eliminates acid gas through a 5-stage centrifugal compressor to prevent an excessive increase in temperature.
04 Refining Process
After being compressed and dried, the cracked gas is cooled to -167℃ in the cold box and separates substances additional to hydrogen and methane. Hydrocarbon compounds additional to methane are separated in stages due to the difference in boiling points. Going through the distillation tower, reactor, absorption tower, and Rectifying Tower, products of the desired quality (ethylene, propylene, C3LPG, Mixed-C4, PG) are produced and supplied to the raw material storage tank downstream. Ethane produced at the bottom of the ethylene tower is recycled through the cracking of ethane.
