Fullname: Nguyễn Đức Ánh
Class: K4
ID: CTTT 13210105
ADECH 04



ETHYLENE GLYCOL PRODUCTION
Interpretation of Shell- OMEGA technology for Ethyleneglycol (EG) manufacturing

In the traditional process of MEG production, the ethylene is reacted with pure oxygen for producing EO and CO2 as a by-product. The EO is distilled and further reacted with lots of water in the glycol section. The reaction produces MEG along with the higher glycol by-products.

The Omega process in the glycol section is designed to make use of the CO2 produced during the EO reaction. The CO2 converts EO into ethylene carbonate, which is then treated with water to produce MEG, eliminating by-products formation.
Ethylene oxide production:
In the Ethylene oxide reactor (1) Ethylene and oxygen are mixed with recycle gas and, fed into a multitubular reactor. There, ethylene oxide (EO) is selectively produced utilizing a silver-based catalyst at about 200 to 300 °C and 10-20 bar. Along with ethylene oxide (80-85 %), CO2, H2O and heat are generated. Reaction heat is recovered by boiling water at elevated pressure on the reactors shellside.
𝐶
𝐻
2=𝐶
𝐻
2+0.5 𝑂
2
250−330𝐶(𝐶
𝐻
2
2
𝑂

𝐻
298
0= −105 𝑘𝐽/𝑚𝑜𝑙
𝐶
𝐻
2=𝐶
𝐻
2+3
𝑂
2→2 𝐶
𝑂
2+2
𝐻
2
𝑂
𝐻
298
0= −135 𝑘𝐽/𝑚𝑜𝑙
(𝐶
𝐻
2
2
𝑂+2.5 𝐶
𝑂
2→ 2 𝐶
𝑂
2+2
𝐻
2
𝑂
𝐻
298
0= −1225 𝑘𝐽/𝑚𝑜𝑙


Oxygen is required as reactant to run the process and added to the cycle gas. However, at a certain concentration level (known as flammable limit) in the gas mixture, oxygen will cause the danger of a gas explosion. Therefore, the content of oxygen in the cycle gas must be monitored continuously with high accuracy and reliability
Catalyst selectivity is an important parameter in EO production and should be as high as possible
Ethylene oxide recovery:
EO contained in the reactor product gasenters the EO absorber (2) section where EOis scrubbed from the gas by water. which issuitable for feeding directly to a glycolproducing plant.Part of this gaseous overhead stream is recycled to the reactor, while the other part is sent to a carbon-dioxide-removal unit composed of an absorber (5) and a stripper (6). In this unit, CO2 is separated to be used in ethylene carbonate production (7)
In the Ethylene oxide stripper (3)EO-containing water is concentrated bystripping producing crude EO, where it is concentrated and recovered in the overheads. The crude EO stream is condensed. Residual light gases are recovered from it and recycled to the reactor (4). The resulting EO stream is directed to the next section.
Ethylene glycol production and purification.
Ethylene oxide is reacted with CO2, forming ethylene carbonate in the ethylene carbonate reactor (7),and then hydrolyzed to form MEG and CO2 in Hydrolysis reactors (8). Both reactions are carried out in the liquid phase using homogeneous catalysts.
(CH2)2O + CO2 → (CH2O)2CO
(CH2O)2CO + H2O → OH-CH2-CH2-OH + CO2
CO2 streams from the reaction steps are recycled to the ethylene carbonate reactor. Water in MEG is removed by Water removal column (9) and then MEG is purified in MEG purification column (10) , leading to the final MEG product.
The catalyst is separated and recycled to the ethylene carbonate reactors.

/
Figure 1. Monoethylene glycol (MEG) production, according to a process similiar to the Shell OMEGA process

Draw block diagram of EG production from ethylene by hydration of ethylene oxide
/
Figure 2: Ethylene glycol production by ethylene oxide hydration.















Draw block diagram of EG based on Shell OMEGA technology by ethylene carbonation using CO2



/
Figure 3: Ethylene glycol production by ethylene carbonation based on Shell OMEGA technology




IV.Interpret production of Ethyleneglycol (EG) from synthesis gas via dimethyl oxalate

- A gaseous mixture of carbon monoxide (CO) and hydrogen (H2) is separated into H2and CO in Syngas Seperation (1)

Carbonylation
- The recovered CO is fed to the carbonylation reactors along with a recycled stream from the nitrite regeneration section that contains an intermediate (methyl nitrite).Methyl nitrite reacts with CO to produce the intermediate DMO and nitric oxide (NO) over a palladium catalyst in Carbonylation reactor (2)
/


DMO hydrogenation
-The DMO-rich stream is fed to the Hydrogenation reactors (3) along with H2 recovered