As mention on Ethylene Oxide (EO) process the producing EO over a catalyst is the first step in the overall EO/EG manufacturing process. In the reaction section, EO is produced by catalysed, direct partial oxidation of ethylene. Additionally, a portion of the ethylene fully oxidises to form CO and water. These reactions take place in an isothermal (tubular) reactor at temperatures of 230–270°C. The reaction is moderated/optimised using an organic chloride.

EO is recovered from the reactor product gas by absorption in water. Co-produced CO2 and water are removed, and, after the addition of fresh ethylene and oxygen, the gas mixture is returned to the EO reactor as feed. The EO–water mixture can be routed to a purification section for recovery of high-purity EO and/or to a reaction section where EO and water are converted into glycols.

In the standard thermal glycol reaction process, EO and water are reacted at an elevated temperature (about 200°C) and pressure without catalyst.

The proportion of the higher glycols is limited by using excess water to minimise the reaction between the EO and glycols. The resultant water–glycol mixture from the reactor is then fed to multiple evaporators where the excess water is recovered and largely recycled. Finally, the water-free glycol mixture is separated by distillation into MEG and the higher glycols.

A more modern technology is to react EO with CO to form ethylene carbonate (EC) and subsequently react the EC with water to form MEG, both reactions being catalysed. In this two-step process, most of the MEG forms in an EO-free environment, which minimises the co-production of heavier glycols and results in a MEG yield of more than 99%. Figure 1 shows a basic overview of the EO/EG process.

 

Fig 1: Block scheme showing the major sections of the EO/EG process

This process typically used for producing following products:

Mon-ethylene glycol (MEG)

MEG is an organic compound, more specifically a diol (a chemical compound that contains two hydroxyl groups). It is a colorless, practically odorless, with low viscosity, hygroscopic liquid at room temperature. It is in fact the simplest diol and a major chemical commodity that, like other glycols, undergoes reactions common to monohydric alcohols forming esters acetals, ethers, and similar products.

 

Di-ethylene glycol (DEG)

Diethylene glycol (DEG) is an oligomer of Ethylene Glycol with chemical formula C4H10O3. It is formed as byproduct during the synthesis of ethylene oxide and MEG or prepared directly by the reaction of MEG with ethylene oxide. DEG is employed in a number of applications, such as in the manufacture of unsaturated polyester resins, polyurethanes, and plasticizers, as solvent, softener (cork, adhesives, etc), dye additive, deicing agent and drying agent.

 

Tri-ethylene glycol (TEG)

Triethylene glycol (TEG) is a higher homologue of Ethylene Glycol with chemical formula C6H14O4. It is formed as by-product during the synthesis of ethylene oxide and MEG or prepared directly by the reaction of MEG with ethylene oxide. Figure 2 shows the chemical structure of MEG, DEG and TEG.

Fig 2. The chemical structure of MEG, DEG and TEG.

 

OPERATING COSTS

The monoethylene Glycol (MEG) production from ethylene oxide operational expenditures (OPEX), these encompass costs associated with the plant operation and depreciation. In the current analysis, the operating cost was grouped under three main headings:

  • Operating variable costs: Costs directly proportional to the actual operating rate of the industrial site (i.e. raw materials and utilities consumption)
  • Operating fixed costs: Operating costs directly tied to the plant capacity, but which do not change with the operating level (i.e., operating labor, supervision labor, maintenance costs, plant overhead)
  • Depreciation: Refers to the decrease in value of industrial assets with passage of time

 

It should be kept in mind that the sum of operating fixed costs and operating variable costs is referred as “cash cost”. The sum of cash cost with depreciation, in turn, is referred to as “total operating cost”.

The figure 3 is the graph below illustrates the composition of total operating cost.

Application of Glycols

A significant utilization of ethylene glycol is as radiator fluid for inside consuming motors. Arrangement contain ethylene glycol involve incredible warmth transport property & the upper singing focuses that the unadulterated H2O.

Subsequently, when the expanding inclination as utilize Glycol arrangement as well as an all year coolant. Ethylene glycol arrangements are additionally utilized as evolved heat move specialist.

Mixture of two chemical reaction should be utilized intended for thaw out and the airplane & forestall. Then the setup of ice fort the airplane as on top of earth. It is based on the definitions and additionally second-hand to deice landing strip runway runways as deicing moderator.

The asphalt emulsion paints are shielded for the expansion for ethylene glycols close by cold, break then the blend. A carbon-dioxide bothered blaze and the framework regularly encompasses Ethylene glycol the maintain a strategic distance from cold.