Plant #1 > EG
The EG plant produces EO (Ethylene Oxide) by oxidizing the raw material ethylene and oxygen at high temperature and pressure with silver acting as a catalyst and makes this into HPEO (high-purity ethylene oxide), MEG, DEG, and TEG products. The EG plants that introduced Shell Corporation’s technology began commercial production at Plant #1 (EG1) in 1979, Plant #2 in 1991 (EG2), and Plant #3 in 1997 (EG3). Currently, they have the annual production capacities of 400 thousand tons of MEG and 170 thousand tons of HPEO. The main product MEG is used primarily as raw material for artificial fibers such as polyester and HPEO as raw material for EOA and as disinfectants.
■ Production process
01 Raw Material Supply
The ethylene (C2H4) supplied from the ethylene plant maintains the constant temperature (>10℃) and pressure (>26kg/cm²) and traces of sulfur content are eliminated from the Sulfur Guard Bed filled with active carbon to be supplied to the EO reactor. The O2 supplied from the air separation plant is evenly mixed with recycled gas in the specially designed 02 mixing nozzle.
02 EO Reaction
The ethylene and oxygen supplied to the EO reactor create ethylene oxide and carbon dioxide in the silver-catalyzed reactions, with the reaction heat eliminated by generating steam necessary for the process.
03 EO Recovery
The EO and non-reactive gas created from the EO reactor are supplied to the EO absorption tower. EO is recovered as an EO aqueous solution by process water for absorption; the non-reactive gas is compressed in the RG compressor and recycled into the EO reactor. The EO absorption liquid is decompressed and heated in the EO recovery tower to recover EO, and the residual liquid is cooled in the process cooling tower before being recycled into the EO absorption tower.
04 CO2 Elimination
To eliminate the CO2 produced by the side reaction at the time of EG reaction, part of the recycled gas is supplied to the CO2 absorption tower for absorption by 20wt% K2CO3 solution and decompressed and heated in the CO2 recovery tower to eliminate CO2.
05 EO Refining
The EO recovered from the EO recovery tower is cleared of light gas such as C02, C2H4, and CH4 in the ight ends column and is subjected to the refining process in the EO refining tower to produce high-purity EO and low-purity EO. The high-purity EO is stored for sale and supplied as raw material for the low-purity EG section.
06 EG Reaction
EO is subjected to react with an excess of water without a catalyst at high temperature and pressure in the EG reactor. The creation ratio between MEG, DEG, and TEG varies according to the ratio of EO to water. In general, MEG 90.5 wt%, DEG8.9wt%, and TEG 0.6wt% are generated.
07 EG Recovery
EG and water go through 3 stages of concentrating process and 1 stage of dehydration process. After being completely cleared of water, it is transferred to the EG refining sector. The overhead steam in each tower is used as reboiler steam in the next tower, thereby saving energy.
08 EG Refining
Going through the MEG, DEG, and TEG refining tower, EG produces MEG, DEG, and TEG products by vacuum rectification, whose purpose is to prevent the thermal cracking of EG.
