Processes and production plants for producing polyols

A production plant for preparing a polyol, comprising:

• (a) a first reactor comprising:
• (1) an inlet in fluid communication with a source of alkylene oxide;
• (2) an inlet in fluid communication with a source of starter;
• (3) an inlet in fluid communication with a source of DMC catalyst;
• and
• (4) an outlet configured to continuously discharge an intermediate polyol from the first reactor;
• (b) a source of an aqueous solution of alkali metal in fluid communication with the outlet of the first reactor and configured to continuously add the aqueous solution of alkali metal to the intermediate polyol as it is continuously discharged from the first reactor, thereby producing a mixture comprising the intermediate polyol, the alkali metal and water;
• (c) a dehydration apparatus comprising a polyol inlet and a polyol outlet, wherein the polyol inlet is in fluid communication with the outlet of the first reactor, wherein the dehydration apparatus is configured to continuously remove water from the mixture comprising the intermediate polyol, the alkali metal and water, thereby producing a dehydrated mixture comprising the intermediate polyol and the alkali metal;
• (d) a second reactor comprising:
• (1) an inlet that is in fluid communication with the outlet of the dehydration apparatus and configured to receive the dehydrated mixture comprising the intermediate polyol and the alkali metal;
• (2) an inlet in fluid communication with a source of alkylene oxide;
• and
• (3) an outlet configured to discharge the polyol from the second reactor.