Method of recovering phenol from a BPA production facility and the facility for recovering the same

A system for recovering phenol comprising:

• a phenol purification section of a phenol production facility comprising
• a preheater comprising a preheater inlet and a preheater outlet,
• a splitter column comprising a splitter inlet in fluid communication with the preheater outlet, a splitter top outlet, and a splitter bottom outlet,
• a crude phenol column comprising a crude inlet in fluid communication with the splitter bottom outlet, a crude top outlet, and a crude bottom outlet,
• a hydro-extractor column comprising an extractor inlet in fluid communication with the crude top outlet, an extractor outlet, and an extractor primary outlet, and
• a finishing column comprising a finisher inlet in fluid communication with the extractor primary outlet, a product phenol outlet, and a finisher bottom outlet;
• and
• a bisphenol A production facility comprising
• a bisphenol A reactor comprising a bisphenol A reactor inlet and a bisphenol A reactor outlet;
• a crystallization unit comprising a crystallization inlet and a crystallization outlet;
• wherein the crystallization inlet in in fluid communication with the bisphenol A reactor outlet;
• a melting unit comprising a melting unit inlet and a melting unit outlet;
• wherein the melting unit inlet is in fluid communication with the crystallization outlet;
• a filter comprising a filter inlet and a filter outlet;
• wherein the filter inlet is in fluid communication with the melting unit outlet;
• and
• a water stripper comprising a filtered stream inlet, a water stream outlet, and an unreacted phenol stream outlet;
• wherein the filtered stream inlet is in fluid communication with the filter outlet;
• wherein a purge stream comprising at least a portion of the unreacted phenol stream outlet of the bisphenol A production facility is in intermittent fluid communication or is in constant fluid communication with the phenol purification section upstream of the finishing column;
• and wherein the system is configured such that the purge stream exiting the unreacted phenol stream outlet comprises 60 to 90 wt % of an unreacted phenol based on the total weight of the purge stream.

A method of recovering an unreacted phenol from a bisphenol A production facility comprising:

• reacting an initial phenol and an initial acetone in the presence of a catalyst to produce a bisphenol A stream comprising the unreacted phenol of the initial phenol and a bisphenol A;
• separating a purge stream comprising the unreacted phenol;
• wherein the unreacted phenol is present in the purge stream in an amount of 60 to 90 wt %, based on the total weight of the purge stream;
• wherein the separating the purge stream comprises crystallizing the bisphenol A in the bisphenol A stream in the presence of water to form crystals comprising one or both of crystalline bisphenol A and an adduct of bisphenol A and the unreacted phenol, forming a crystallized stream, melting the crystallized stream to form a melted stream, filtering the melted stream to form a filtered stream, removing the water from the filtered stream in a water stripper to form a water stream and an unreacted phenol stream, wherein the purge stream comprises all or a portion of the unreacted phenol stream;
• adding the purge stream to a phenol purification section of a phenol production facility;
• and
• forming a purified phenol outlet stream in the phenol purification section, wherein the purified phenol outlet stream comprises a total phenol concentration of greater than or equal to 99.5 wt % based on the total weight of the purified phenol outlet stream;
• wherein the forming the purified phenol outlet stream comprises heating a preheater inlet stream comprising cumene, a product phenol from the phenol production facility, and a product acetone from the phenol production facility in a preheater to form a splitter inlet stream;
• separating the splitter inlet stream into a splitter top outlet stream comprising the product acetone and the cumene and a splitter bottom outlet stream comprising the product phenol in a splitter column;
• separating the splitter bottom outlet stream into a crude top outlet stream comprising the product phenol and a crude bottom outlet stream comprising the cumene in a crude phenol column;
• hydro-extracting the crude top outlet stream in a hydro-extractor column to form an extractor primary outlet stream comprising the product phenol;
• and recovering the purified phenol outlet stream, from the extractor primary outlet stream in a finishing column;
• wherein the adding the purge stream comprises adding the purge stream to one or more of the preheater inlet stream, the splitter inlet stream;
• the splitter bottom outlet stream;
• and the crude top outlet stream.