The ethylene glycol product stream (34) emerging from the ethylene glycol reactor is supplied to a multistage evaporator system (35). 1) varies with the pH of the stream. Although the concentration of salts of organic acids in the ethylene oxide absorber is low, continued hydrolysis of the glycol esters in positions downstream of the ethylene oxide absorber can lead to a gradual increase in organic acids and a resulting decrease in pH. Preferably, the base is added such that a pH is maintained in the range of 5.5 to 9.5. 1 for producing ethylene oxide. The lean absorbent stream is recirculated to the ethylene oxide absorber. •This compound is produced from the hydration of EO which may produce in addition to ethylene glycol diethylene glycols and triethylene glycols. FIG. However, addition of too much base could increase the pH above 9.5 and this is also undesirable. 5,336,791. This make-up water contains low levels of amines or other chemicals to control the make-up water pH. Dosing an additional amount of sodium hydroxide solution into the quench bleed stream (14) solved that problem. Figure 1 depicts MEG production from ethylene via a process similar to the OMEGA catalytic process from Shell Global Solutions (The Hague, the Netherlands; www.shell.com). A quench bleed (14) is withdrawn from the recirculating aqueous solution (12) and is passed to an ethylene oxide removal unit (15), which could be a pipe reactor wherein ethylene oxide is hydrolysed to ethylene glycol, producing a dilute aqueous ethylene glycol solution or could be an ethylene oxide stripper wherein ethylene oxide is stripped and sent back to the ethylene oxide absorber (7,8). The water depleted ethylene glycol stream typically consists of 70 to 95 weight % monoethylene glycol, with the remainder being diethylene glycol and triethylene glycol and is supplied to a fractional distillation system wherein the individual glycol products are recovered at high purity level. This includes into the fat absorbent stream (22), to the ethylene oxide stripper (23), to the lean absorbent stream (24), to the slip stream (30), to the water streams (29), to the quench bleed stream (14), to the dilute aqueous ethylene glycol solution (16), to the two-phase slurry containing stream (18) and to the glycol stream (32). it is not added to reactants or products in the gaseous phase). the concentrated ethylene oxide stream, (26), the lean absorbent stream (24), the water streams (29)) can be supplied to the ethylene glycol reactor (33), which is a noncatalytic pipe-type reactor. Ethylene oxide (EO) and ethylene glycol (EG) are widely used industrial organic intermediates. It is produced by the direct oxidation of ethylene with oxygen or air. The EO is first produced by the oxidation of ethylene in the presence of oxygen or air and a silver oxide … The quench bleed is typically treated to remove or recover ethylene oxide, to recover ethylene glycol and to remove heavies such as sodium salts. The reaction of ethylene oxide with water typically produces a glycol product stream consisting of almost 90 weight percent monoethylene glycol, the remainder being predominantly diethylene glycol, some triethylene glycol and a small amount of higher homologues. The invention provides a process for the production of ethylene oxide and, optionally, ethylene glycol. Ethylene oxide p… In ethylene glycol sections of the plant, a pH above 9.5 can reduce the quality of the ethylene glycol product. However, the present inventors have observed corrosion of sections of ethylene oxide/ethylene glycol (EO/EG) plants and have sought to understand the mechanism of this corrosion and thereby provide solutions for mitigating this corrosion. The ethylene, oxygen, ballast gas and inhibitor are preferably supplied to recycle gas that is supplied to the ethylene oxide reactor from the ethylene oxide absorber. FIG. This mitigates corrosion in the ethylene oxide and ethylene glycol plant. In a preferred embodiment, the pH is maintained in the range of 5.5 to 9.5, preferably from 6 to 9 and most preferably from 6.5 to 8.5 in all regions where glycol esters are hydrolysed to organic acid and ethylene glycol. The glycol product stream is passed through successive distillation columns with decreasing pressure to remove water, which is returned to the ethylene glycol reactor. This indicates that corrosion is very likely to occur if the pH of the bleed stream is below 6.5. Ethylene glycol used to be manufactured by the hydrolysis of ethylene oxide (EO) which was produced via ethylene chlorohydrin but this method has been superseded by a direct oxidation route. It may be preferable to use an organic base, typically an amine, for addition at points in the ethylene glycol plant, particularly into water that is recycled from the evaporator system to the ethylene glycol reactor. In many ethylene oxide plants, the lean absorbent is exposed to an open cooling tower, but for environmental reasons newer plants tend to have closed cooling systems.