Oxygenate removal unit

When a higher C4 raffinate purity is required it is possible to perform a more efficient removal of oxygenates (mainly DEE) by including an additional distillation tower or an oxygen removal unit (ORU) based on molecular sieves. 

Figure 3 shows a simple schematic diagram of an oxygen-based process. Ethylene, oxygen, and the recycle gas stream are combined before entering the tubular reactors. The basic equipment for the reaction system is identical to that described for the air-based process, with one exception the purge reactor system is absent and a carbon dioxide removal unit is incorporated. The CO2 removal scheme illustrated is based on a patent by Shell Oil Co. (127), and minimises the loss of valuable ethylene in the process. 

Design Flow Chemical Oxygen Demand (COD) Metals Removal Unit Sludge Dewatering System Mode Capital (Smillion) O M ( 1000 lb COD) O M ( 1000 gallon)... 

Synthesis gas may be prepared by a continuous, noncatalytic conversion of any hydrocarbon by means of controlled partial combustion in a fire-brick lined reactor. In the basic form of this process, the hydrocarbon and oxidant (oxygen or air) are separately preheated and charged to the reactor. Before entering the reaction zone, the two feed stocks are intimately mixed in a combustion chamber. The heat produced by combustion of part, of the hydrocarbon pyrolyzes the remaining hydrocarbons into gas and a small amount of carbon in the reaction zone. The reactor effluent then passes through a waste-heat boiler, a water-wash carbon-removal unit, and a water cooler-scrubber. Carbon is recovered in equipment of simple design in a form which can be used as fuel or in ordinary carbon products. 

Fresh acetic acid and a liquid acetic acid recycle stream are fed into a vaporizer along with a gas recycle stream and fresh ethylene feed. Oxygen is added after the vaporizer, and reactions occur in a gas-phase reactor. Reactor effluent is cooled and fed into a separator. Vapor from the separator is compressed and fed into an absorber to recover vinyl acetate. Recycle acetic acid is used as lean oil in the absorber. Exit gas from the absorber is sent to a CO2 removal unit, which produces a CO2 purge stream and gas recycle. Another purge stream is used to remove the small amount of ethane that is in the fresh ethylene makeup feed. 

Figure 2. Effect of oxygen in the photovoltaic response of the platinized Chi a electrode, (a) Electrolyte purged with argon gas, measurements made under a positive pressure of Ar (b) O, electrolyte saturated with oxygen (c) , oxygen removed by passage of argon gas through the electrolyte solution for 30 min. The ordinate units are given in 10 electrons per incident photon. The efficiency of the liquid junction cell was calculated by dividing the photovoltaic response (electrons sec ) by the incident photoresponse (photons sec ).

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