Process for reducing the overchloriding of high selectivity ethylene oxide catalysts during restarts

A method for restarting an ethylene oxide production process after a period of being shutdown for at least one hour following a continuous steady state period, wherein during the continuous steady state period the process is operated by:

• (i) feeding a reactor feed gas to a reactor containing a batch of a high-selectivity, rhenium-promoted silver catalyst, wherein the reactor feed gas comprises ethylene at a pre-shutdown steady state ethylene concentration, oxygen at a pre-shutdown steady state oxygen concentration, and at least one organic chloride at a pre-shutdown steady state at least one organic chloride concentration, wherein the at least one organic chloride comprises vinyl chloride at a pre-shutdown steady state vinyl chloride concentration, to yield a reactor product comprising ethylene oxide at a pre-shutdown steady-state value of a selectivity of the process toward the production of ethylene oxide, wherein the ethylene oxide production process is characterized by an ethylene oxide production parameter having a pre-shutdown steady state value, and a reaction temperature has a pre-shutdown steady state reaction temperature value;
• (ii) recycling a portion of the reactor product to form a reactor recycle;
• and (iii) combining the reactor recycle with make-up streams comprising at least make-up ethylene at a pre-shutdown steady-state feed rate of make-up ethylene, make-up oxygen at a pre-shutdown steady state feed rate of make-up oxygen, and a make-up organic chloride selected from ethyl chloride and ethylene dichloride at a pre-shutdown steady state feed rate of the make-up organic chloride, to form the reactor feed gas, wherein the period of being off-line is a period during which no make-up oxygen is fed to the batch of the high-selectivity, rhenium-promoted silver catalyst, the method for restarting comprising:
• again feeding a reactor feed gas to the batch of the high-selectivity, rhenium-promoted, silver catalyst, wherein during the step of again feeding a reactor feed gas, the reactor feed gas initially comprises ethylene at an initial ethylene restart concentration and the at least one organic chloride at an initial restart concentration of the at least one organic chloride, and the reactor feed gas is formed by combining the reactor recycle with make-up streams comprising at least make-up ethylene at an initial restart feed rate of make-up ethylene and make-up oxygen at an initial restart feed rate of make-up oxygen;
• and
• adjusting the reaction temperature to an initial restart reaction temperature value that is no more than five (5) degrees Celsius above an initial start-up steady-state reaction temperature value when the high-selectivity catalyst was fresh.