Full Name : Nguyen Van Phuong
Class : K4
ID : CTTT13210146
ADECH 04
Selfstydy #1
Interpret production of Ethyleneglycol (EG) from synthesis gas via dimethyl oxalate .
In the process described here, ethylene glycol is produced from synthesis gas (syngas), a gaseous mixture of carbon monoxide (CO) and hydrogen (H2).
The CO and H2 in the feed syngas are separated. The recovered CO is fed to the carbonylation reactors along with a recycled stream from the nitrite regeneration section (discussed below) that contains an intermediate (methyl nitrite). Methyl nitrite reacts with CO to produce the intermediate DMO and nitric oxide (NO).
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Carbonylationprocess :
Carbonylation reaction of CO and MN takes place over Pd catalyst. Pujing Chemical employed proprietary technology to prepare egg-shell Pd/a-Al2O3 catalyst, and studied the influence of precursors’ pH value on the depth of egg shell and investigated the activity and selectivity during the reaction for serial C catalysts.
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DMO hydrogenation :
The DMO-rich stream is fed to the hydrogenation reactors along with H2 recovered from the syngas feed. DMO reacts with H2 to produce the final product, ethylene glycol and methanol. The product stream from the hydrogenation reactors is partially condensed, and the condensate is directed to the purification section.
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Purification
The purification system consists of a series of distillation steps to separate fiber-grade ethylene glycol from methanol and other byproducts formed during DMO hydrogenation. Methanol is recovered from an intermediate distillation column and is recycled to the nitrite-regeneration section. Nitrite regeneration. The recovered NO stream from the carbonylation section is mixed with O2 and contacted
The top product stream from the nitrite reactor is partially condensed to remove most of its water and the resulting methyl-nitrite-rich stream is recycled to the carbonylation section. The reactor bottom product is directed to a water-removal distillation column.
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Draw block diagram of EG from synthesis gas via dimethyl oxalate.
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Comment on advantage and disadvantage of hydration, carbonylation and Shell OMEGA technologies.
Fermentation vsHydration :
Advantages
Disadvantages

Fermentation: Sustainable resource
Fermentation: Zymase denatures at acohol content of 14%, so has to be replaces- no continous process.

Fermentation: Lower temperature and pressure
Fermentation: Risk of impure product.

Fermentation: `Carbon neutral` as when burnt, the CO2 release is used by plants which are then used as fuels again.
Fermentation: Takes longer than hydration

Hydration: Continous reaction using phosphoric acid catalyst. Also allows high percentage yield.
Hydration: Very high temperature (300 centigrade) and pressure (70atm) are expensive and difficult to maintain.

Hydration: 100% atom economy as only one product.
Hydration: Unsusatianble source- alkenes come from cude oil.


Interpretation of Shell- OMEGA technology for Ethyleneglycol (EG) manufacturing.
Shell OMEGA technology is a two-step process in which EG is produced from ethylene oxide (EO) via ethylene carbonate (EC), the latter being produced as an intermediate product. EO, for this process, is produced through the conventional EO technology of Shell, using a proprietary Ag-based, promoted catalyst. Ethylene conversion is 10 to 15% and EO selectivity is 90%. EC is produced from EO using a phosphonium halide catalyst The overall result of the twostep process is that MEG yield in ethylene glycols product is extremely high (99–99.5%). This is the main advantage of this new technology that it selectively produces MEG and minimizes the production of di-ethylene and tri-ethylene glycols. According to Shell, higher growth rate in MEG demand than for DEG was a major factor for the commercialization of technology.
In the early days of EO production, the typical start-of-cycle selectivity for EO catalysts ranged from 68 to 70%, i.e., 30% or more of the ethylene feed to the process was lost to the complete combustion side reaction. Then, in 1971, Shell identified an improvement to the catalyst formulation that helped to boost catalyst selectivity to over 80%.
Conventionally, monoethylene glycol (HOC2H4OH) is produced by the controlled hydrolysis of ethylene oxide (C2H4O). The monoethylene glycol product is also able to react with ethylene oxide to give diethylene glycol, and so on; sequential reaction with ethylene oxide is how (ethylene glycolis produced. Due to monoethylene glycol`s high boiling point, purification by distillation is energy intensive.
C2H4O + H2O → HOC2H4OH
In the OMEGA process, the ethylene oxide reacts with (CO2) to yield (C3H4O3). Ethylene carbonate is subsequently hydrolyzed to monoethylene glycol and carbon dioxide. The carbon dioxide is released in this step again and can be fed back into the process circuit. This process is 99.5% selective for monoethylene glycol.
C2H4O + CO2 → C3H4O3
C3H4O3 + H2O → HOC2H4OH + CO2

Draw block diagram of EG production from ethylene by hydration of ethylene oxide
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Draw block diagram of EG based on Shell OMEGA technology by ethylene carbonation using CO2.
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