PHENOL RECOVERY OF BISPHENOL-A MOTHER LIQUOR PURGE USING PURIFICATION TRAIN IN THE PHENOL PRODUCTION UNIT

Systems and methods for recovering phenol have been disclosed. The methods of recovering phenol includes concurrently processing, in a phenol recovery unit, a crude phenol stream from a phenol production unit, and a bisphenol-A purge stream from a bisphenol-A production unit to produce a first product stream comprising 60 to 95 wt. % phenol. The phenol recovery unit comprises a crude phenol distillation column and a bisphenol-A-phenol distillation column. The processing includes distilling a bottom stream from the crude phenol distillation column in the bisphenol-A-phenol distillation column.

FIELD OF INVENTION

The present invention generally relates to phenol recovering processes. More specifically, the present invention relates to a system and a method for recovering phenol from a purge stream of a BPA production unit in a phenol production unit.

BACKGROUND OF THE INVENTION

Phenol is an aromatic compound used as a precursor for many chemicals and materials. It is used for producing plastics including polycarbonates, epoxies, bakelite, and nylon. Phenol is also used in herbicides, and drug production. Bisphenol-A (BPA) is a precursor for various plastic materials, including polycarbonates, polysulfones, and epoxy resins. These plastic materials are used to manufacture water bottles, food containers, sports equipment, water pipes, etc. Thus, there is a large demand for BPA.

Conventionally, phenol along with acetone, is produced by oxidation of cumene followed by a cleavage reaction. BPA is generally produced by a condensation reaction between acetone and phenol in a condensation reactor. The resulting effluent from the condensation reactor is then dehydrated, crystallized and prilled to produce purified BPA prills.

In the conventional process for producing BPA, a BPA production plant sends the dry mother liquor (DML) purge to a cracking unit for phenol recovery. In the conventional phenol production process, a cracking unit comprising multiple columns is used to crack phenol tar to recover phenol. Generally, the phenol recovery step for both BPA and phenol production units consumes a large amount of energy, resulting in high production costs for BPA and/or phenol.

Overall, while the systems and methods for recovering phenol from BPA and phenol production systems exist, the need for improvements in this field persists in light of at least the aforementioned drawbacks of the conventional system and method.

BRIEF SUMMARY OF THE INVENTION

A solution to at least some of the above-mentioned problems associated with

systems and methods for recovering phenol from a purge stream flowing from a BPA production system and/or from a crude phenol stream flowing from a phenol production system has been discovered. The solution resides in a method of recovering phenol including concurrently processing a bisphenol-A purge stream (e.g., the mother liquor purge stream) in a phenol recovery system including processing phenol tar from a phenol production unit and bisphenol-A tar from a bisphenol production unit in the same cracker. This can be beneficial for at least reducing the capital expenditure and operation costs compared to conventional methods, which utilize separate crackers for phenol tar and bisphenol-A. Additionally, the disclosed method integrates the phenol production system and bisphenol production system for optimal phenol production, thereby reducing overall phenol consumption for producing bisphenol-A. Therefore, the disclosed method and system of the present invention provide a technical achievement over the conventional systems and methods for recovering phenol from a phenol production process and a bisphenol-A production process.

Embodiments of the invention include a method of recovering phenol. The method comprises concurrently processing, in a phenol recovery system, (i) a crude phenol stream comprising phenol and phenol tar and (ii) a bisphenol-A purge stream comprising phenol and bisphenol-A tar to produce a first product stream comprising 60 to 95 wt. % phenol. The phenol recovery system comprises a crude phenol distillation column and a bisphenol-A-phenol distillation column. The processing comprises distilling a bottom stream from the crude phenol distillation column in the bisphenol-A-phenol distillation column.

Embodiments of the invention include a method of recovering phenol. The method comprises concurrently processing, in a phenol recovery system, (i) a crude phenol stream comprising phenol and phenol tar and (ii) a bisphenol-A purge stream comprising phenol and bisphenol-A tar to produce a first product stream comprising 60 to 95 wt. % phenol. The phenol recovery unit comprises a crude phenol distillation column and a bisphenol-A-phenol distillation column. The processing comprises distilling a bottom stream from the crude phenol distillation column in the bisphenol-A-phenol distillation column. The distilling produces a bisphenol-A-phenol distillation column bottom stream comprising primarily phenol tar and bisphenol-A tar, collectively. The method further comprises subjecting the bisphenol-A-phenol distillation column bottom stream to reaction conditions sufficient to crack the phenol tar and/or the bisphenol-A tar to produce additional phenol.

Embodiments of the invention include a method of recovering phenol. The method comprises concurrently processing, in a phenol recovery unit, (i) a crude phenol stream comprising phenol and phenol tar and (ii) a bisphenol-A purge stream comprising phenol and bisphenol-A tar to produce a first product stream comprising 60 to 95 wt. % phenol. The processing comprises combining the crude phenol stream and the bisphenol-A purge stream to form a feed stream. The processing further comprises distilling the feed stream in the crude phenol distillation column to form a first top stream comprising 85 to 99 wt. % phenol and a first bottom stream comprising phenol and combined phenol tar and bisphenol-A tar. The processing further comprises distilling the first bottom stream in the bisphenol-A-phenol distillation column to produce an intermediate phenol stream comprising phenol and bisphenol-A column bottom stream comprising combined phenol tar and bisphenol-A tar. The processing further comprises distilling the intermediate phenol stream in the crude phenol distillation column to produce additional phenol in the first top stream. The method further comprises subjecting the bisphenol-A column bottom stream to reaction conditions sufficient to crack the phenol tar and/or the bisphenol-A tar to produce additional phenol.

The terms “wt. %”, “vol. %” or “mol. %” refer to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component. In a non-limiting example, 10 moles of component in 100 moles of the material is 10 mol. % of component.

The terms “inhibiting” or “reducing” or “preventing” or “avoiding” or any variation of these terms, when used in the claims and/or the specification, include any measurable decrease or complete inhibition to achieve a desired result.

The process of the present invention can “comprise,” “consist essentially of,” or “consist of” particular ingredients, components, compositions, etc., disclosed throughout the specification.

The term “primarily,” as that term is used in the specification and/or claims,

means greater than any of 50 wt. %, 50 mol. %, and 50 vol. %. For example, “primarily” may include 50.1 wt. % to 100 wt. % and all values and ranges there between, 50.1 mol. % to 100 mol. % and all values and ranges there between, or 50.1 vol. % to 100 vol. % and all values and ranges there between.

DETAILED DESCRIPTION OF THE INVENTION

Currently, phenol is recovered by cracking bisphenol-A tar of a bisphenol-A purge stream from a bisphenol-A production unit and/or cracking a phenol tar produced in a phenol production unit in two separate cracking units, resulting in high energy consumption and high production cost for phenol. Additionally, the conventional phenol production unit and bisphenol-A production unit are separate with some of the operation units configured to perform similar processes, resulting in high expenditure and operation costs. The present invention provides a solution to at least some of these problems. The solution is premised on a system and a method for recovering phenol from a bisphenol-A purge stream comprising bisphenol-A tar and a phenol process stream comprising phenol tar in the same cracker, thereby reducing capital expenditure and operating costs. These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.

A. System for recovering phenol

In embodiments of the invention, the system for recovering phenol comprises a crude phenol distillation column, a bisphenol-A-phenol distillation column, a hydro-extraction unit, and a cracker. Notably, the system is capable of processing combined phenol tar and bisphenol-A tar in a single cracker, resulting in reduced capital expenditure and operating costs for recovering phenol and BPA, compared to conventional systems. With reference toFIGS.1A-1C, schematic diagrams are shown for systems100,200, and300, respectively, which can be used for recovering phenol.

According to embodiments of the invention, as shown inFIG.1A,1B, or1C, system100,200, and/or300comprise crude phenol distillation column101. Crude phenol distillation column101can be a crude phenol distillation column of a phenol production system. In embodiments of the invention, the phenol production system can include a cumene-based phenol production system comprising an oxidation reaction unit configured to react cumene with air to produce cumene hydroperoxide (CHP), a cumene stripping unit configured to strip cumene from the effluent of the oxidation reaction unit, a cleavage unit configured to decompose the cumene hydroperoxide to produce phenol and acetone under acidic reaction conditions, a neutralization unit configured to neutralize an effluent of the cleavage unit to produce a first wastewater stream and a neutralized phenol stream. The phenol production system further comprises an acetone fraction unit configured to separate the neutralized phenol stream to produce crude phenol stream11comprising primarily phenol. Crude phenol stream11can further comprise cumene, alpha-methylstyrene (AMS), heavy components, or combinations thereof.

According to embodiments of the invention, an outlet of crude phenol

distillation column101is in fluid communication with an inlet of bisphenol-A-phenol distillation column102. In embodiments of the invention, bisphenol-A-phenol distillation column102may include a bisphenol-A-phenol distillation column of a BPA production system.

In embodiments of the invention, the BPA production system includes a bisphenol-A synthesis reactor configured to react acetone with phenol to produce BPA, a dehydration unit configured to remove water from an effluent from the condensation reaction unit comprising one or more BPA synthesis reactors to produce a second wastewater stream comprising phenol and water, and a crude BPA stream comprising BPA. The crude BPA stream may include 5 to 25 wt. % BPA. In embodiments of the invention, the second wastewater stream further comprises acetone and/or sodium hydroxide. The BPA production system may further comprise a BPA concentration unit configured to concentrate the crude

BPA stream, and an adduct crystallization unit configured to crystalize BPA of an effluent from the concentration unit to produce (1) crystalized BPA and (2) a mother liquor comprising bisphenol-A tar, a solvent, and water. The BPA production system may further comprise a solvent recovery unit configured to recover the solvent from the mother liquor and produce a dry mother liquor (DML) stream. The dry mother liquor stream is further split to form a dry mother liquor (DML) purge stream comprising the bisphenol-A tar, a solvent, and water. In embodiments of the invention, the BPA production system is located near the phenol production system.

According to embodiments of the invention, in system100as shown inFIG.1A, crude phenol stream11and bisphenol-A purge stream12can form first combined stream13. Bisphenol-A purge stream12may include the mother liquor purge stream from the BPA production system. In embodiments of the invention, crude phenol distillation column101is configured to distill first combined stream13to produce first top stream14comprising primarily phenol and first bottom stream15comprising phenol, combined phenol tar and bisphenol-A tar. Phenol tar can include acetophenone, dimethylbenzylalcohol, o,p-cumylphenol, alphamethylstyrene dimer, phenol, or combinations thereof. Bisphenol-A tar can include p,p-bisphenol-A, o,p-bisphenol-A, isopropenyl phenol, Chroman, BPX, isopropenyl phenol dimers, spirobi, or combinations thereof.

According to embodiments of the invention, an outlet of crude phenol distillation column101is in fluid communication with an inlet of bisphenol-A-phenol distillation column102such that first bottom stream15flows from crude phenol distillation column101to bi sphenol-A-phenol distillation column102. Bi sphenol-A-phenol distillation column102may be configured to distill first bottom stream15to produce intermediate phenol stream16comprising phenol and bisphenol-A column bottom stream17comprising phenol tar and bisphenol-A tar. Intermediate phenol stream16may further include alpha-methyl styrene, hydroxyl acetone, and 2-methyl benzyl furan. An outlet of bisphenol-A-phenol distillation column102may be in fluid communication with an inlet of crude phenol distillation column101such that intermediate phenol stream16flows from bisphenol-A-phenol distillation column102to crude phenol distillation column101.

According to embodiments of the invention, an outlet of crude phenol

distillation column101is in fluid communication with hydro-extraction unit103such that first top stream14flows from crude distillation column101to hydro-extraction unit103. Hydro-extraction unit103may be configured to separate first top stream14to produce first product stream19comprising primarily phenol and recycle stream18. Recycle stream18may comprise 0.5 to 2 wt. % phenol. Recycle stream18may be recycled to phenol-acetone separation unit, where light components, such as acetone, exist from the top of a distillation column are further purified in an acetone purification train. In embodiments of the invention, as shown inFIG.1A, an outlet of bisphenol-A-phenol distillation column102is in fluid communication with cracking unit104such that bisphenol-A column bottom stream17flows from bisphenol-A-phenol distillation column102to cracking unit104. Cracking unit104can be configured to crack phenol tar and/or bisphenol-A tar in bisphenol-A column bottom stream17to produce a tar stream comprising isopropenyl phenol, isopropenyl phenol dimers and a cracker product stream comprising phenol and/or alpha-methylstyrene (AMS).

According to embodiments of the invention, in system200, as shown inFIG.1B, crude phenol distillation column101is configured to distill crude phenol stream11to produce second top stream24comprising primarily phenol and second bottom stream25comprising phenol tar and phenol. Bisphenol-A-phenol distillation column102, in system200as shown inFIG.1Bis configured to distill bisphenol-A purge stream12and second bottom stream25to produce second intermediate phenol stream26comprising phenol and second bisphenol-A column bottom stream27comprising phenol tar and bisphenol-A tar. Second intermediate phenol stream26may be combined with crude phenol stream11to form second combined stream23as feed stream of crude phenol distillation column101. In embodiments of the invention, as shown inFIG.1B, second top stream24is flowed into hydro-extraction unit103. Hydro-extraction unit103may be configured to separate second top stream24via hydro-extraction to produce second product stream29comprising primarily phenol and second recycle stream28. Second recycle stream may comprises 0.5 to 2 wt. % phenol. In embodiments of the invention, as shown inFIG.1B, second bisphenol-A column bottom stream27is flowed to cracking unit104. Cracking unit104may be configured to crack phenol tar and/or bisphenol-A tar of second bisphenol-A column bottom stream27to produce a tar stream comprising isopropenyl phenol, isopropenyl phenol dimers, and a cracker product stream comprising phenol and/or alpha-methylstyrene (AMS).

According to embodiments of the invention, in system300, as shown inFIG.1C, crude phenol distillation column101is configured to distill crude phenol stream11to produce third top stream34comprising primarily phenol and third bottom stream35comprising phenol tar and phenol. Bisphenol-A-phenol distillation column102, in system300as shown inFIG.1C, can be configured to distill bisphenol-A purge stream12and third bottom stream35to produce third intermediate phenol stream36comprising phenol and third bisphenol-A column bottom stream37comprising phenol tar and bisphenol-A tar. Third intermediate phenol stream36may be combined with third top stream34to form third combined stream33. In embodiments of the invention, as shown inFIG.1C, third combined stream33is flowed into hydro-extraction unit103. Hydro-extraction unit103may be configured to separate third combined stream33to produce third product stream39comprising primarily phenol and third recycle stream38. Third recycle stream38may comprise 0.5 to 2 wt. % phenol. In embodiments of the invention, as shown inFIG.1C, third bisphenol-A column bottom stream37is flowed to cracking unit104. Cracking unit104may be configured to crack phenol tar and/or bisphenol-A tar in third bisphenol-A column bottom stream37to produce a tar stream comprising isopropenyl phenol, isopropenyl phenol dimers, and a cracker product stream comprising phenol and/or alpha-methylstyrene (AMS).

B. Method of recovering phenol

Methods for recovering phenol from a crude phenol stream of a phenol production system and a DML purge stream from a BPA production system have been discovered. As shown inFIGS.2A-2C, embodiments of the invention include methods400,500, and600for recovering phenol. Methods400,500,600may be implemented by systems100,200, and300, respectively, as shown inFIGS.1A-1C, and described above. Each of methods400,500, and600can comprise concurrent processing, in system100,200, or300, of (i) crude phenol stream11comprising phenol and phenol tar and (ii) bisphenol-A purge stream12comprising phenol and bisphenol-A tar to produce a product stream. In embodiments of the invention, the product stream comprises 60 to 95 wt. % phenol and all ranges and values there between including ranges of 60 to 65 wt. %, 65 to 70 wt. %, 70 to 75 wt. %, 75 to 80 wt. %, 80 to 85 wt. %, 85 to 90 wt. %, and 90 to 95 wt. %. Bisphenol-A purge stream12can include a mother liquor purge stream from a bisphenol-A production system.

According to embodiments of the invention, as shown in block401of method400, processing of method400includes combining crude phenol stream11and bisphenol-A purge stream12to form first combined stream13as a feed stream to crude phenol distillation column101. Bisphenol-A purge stream12may include a dry mother liquor purge stream from a bisphenol-A production system. In embodiments of the invention, at block401, crude phenol stream11and bisphenol-A purge stream12may be combined at a volumetric ratio in a range of 1 to 20 and all ranges and values there between including ranges of 1 to 2, 2 to 4, 4 to 6, 6 to 8, 8 to 10, 10 to 12, 12 to 14, 14 to 16, 16 to 18, and 18 to 20.

According to embodiments of the invention, as shown in block402, processing of method400includes distilling first combined stream13in crude phenol distillation column101to form first top stream14comprising primarily phenol and first bottom stream15comprising phenol, phenol tar, and bisphenol-A tar. In embodiments of the invention, first top stream14comprises 85 to 99 wt. % phenol. First bottom stream15may comprise 2 to 15 wt. % phenol, and 85 to 98 wt. % combined phenol tar and bisphenol-A tar. In embodiments of the invention, at block402, crude phenol distillation column101is operated at an overhead temperature range of 120 to 150° C. and a bottom temperature range of 180 to 220° C. Crude phenol distillation column101may be operated at an operating pressure in a range of0.1to bar and all ranges and values there between including ranges of 0.1 to 0.2 bar, 0.2 to 0.3 bar, 0.3 to 0.4 bar, and 0.4 to 0.5 bar. Crude phenol distillation column101may be operated at a temperature in a range of 50 to 250° C. and all ranges and values there between including ranges of 50 to 70° C., 70 to 90° C., 90 to 110° C., 110 to 130° C., 130 to 150° C., 150 to 170° C., and 170 to 190° C.

According to embodiments of the invention, as shown in block403, processing of method400includes distilling first bottom stream15in bisphenol-A-phenol distillation column102to produce bisphenol-A column bottom stream17comprising primarily phenol tar and bisphenol-A tar and intermediate phenol stream16comprising phenol. In embodiments of the invention, at block403, bisphenol-A-phenol distillation column102is operated at an overhead temperature of 80 to 120° C., a bottom temperature of 150 to 200° C., and an operating pressure of 0.2 to 0.8 bar. Bisphenol-A column bottom stream17may comprise 5 to 20 wt. % combined phenol tar and bisphenol-A tar. Intermediate phenol stream16may comprise 60 to 98 wt. % phenol.

According to embodiments of the invention, as shown in block404, processing of method400includes subjecting, in cracking unit104, bisphenol-A column bottom stream17to reaction conditions sufficient to crack the phenol tar and/or the bisphenol-A tar to produce additional phenol. The step of subjecting at block404may further produce tars, and/or AMS. In embodiments of the invention, the subjecting at block404may include contacting bisphenol-A column bottom stream17with an acidic catalyst comprising sulfonic acid, hydrochloric acid, nitric acid, or combinations thereof. In embodiments of the invention, at block404, cracking unit104is operated at an operating temperature of 100 to 250° C. and a pressure of 0.2 to 1.5 bar. According to embodiments of the invention, as shown in block405, processing of method400includes flowing intermediate phenol stream16into crude phenol distillation column101.

According to embodiments of the invention, as shown in block406, processing

of method400includes treating first top stream14in hydro-extraction unit103to form first product stream19comprising primarily phenol and recycle stream18comprising phenol, alpha-methyl styrene, and acetone. At block406, hydro-extraction unit103can include a hydro-extraction column. The hydro-extraction column may be operated at an extraction temperature of 100 to 250° C. and extraction pressure of 0.4 to 2.0 bar. Hydro-extraction unit103at block406may be operated using a solvent comprising water, hydroxyl acetone, and 2-methyl benzyl furan. In embodiments of the invention, recycle stream18is flowed to a phenol-acetone separation column.

According to embodiments of the invention, as shown in block501of method500, processing of method500includes distilling crude phenol stream11in crude phenol distillation column101to form second top stream24comprising primarily phenol, and second bottom stream25comprising phenol, phenol tar, and combinations thereof. In embodiments of the invention, second top stream24comprises 85 to 99 wt. % phenol. In embodiments of the invention, at block501, crude phenol distillation column101is operated at an overhead temperature range of 40 to 150° C. and a bottom temperature range of 80 to 250° C. Crude phenol distillation column101may be operated at an operating pressure in a range of 0.2 to bar and all ranges and values there between including ranges of 0.2 to 0.3 bar, 0.3 to 0.4 bar, 0.4 to 0.5 bar, 0.5 to 0.6 bar, 0.6 to 0.7 bar, and 0.7 to 0.8 bar.

According to embodiments of the invention, as shown in block502, processing of method500includes distilling bisphenol-A purge stream12and second bottom stream25in bisphenol-A-phenol distillation column102to form (1) second bisphenol-A column bottom stream27comprising phenol, phenol tar, and bisphenol-A tar, and (2) second intermediate phenol stream26comprising phenol. In embodiments of the invention, at block502, bisphenol-A-phenol distillation column102is operated at an overhead temperature of 80 to 120° C., a bottom temperature of 150 to 200° C., and an operating pressure of 0.2 to 0.8 bar.

According to embodiments of the invention, as shown in block503, processing of method500includes subjecting, in cracking unit104, second bisphenol-A column bottom stream27to reaction conditions sufficient to crack the phenol tar and/or the bisphenol tar to produce additional phenol. The step of subjecting at block503may further produce tars, and/or AMS. In embodiments of the invention, the subjecting at block503may include contacting second bisphenol-A column bottom stream27with an acidic catalyst comprising sulfonic acid, hydrochloric acid, nitric acid, or combinations thereof. In embodiments of the invention, at block503, reaction conditions in cracking unit104can include an operating temperature of 80 to 300° C. and an operating pressure of 0.5 to 2 bar. According to embodiments of the invention, as shown in block504, processing of method500may include combining second intermediate phenol stream26with crude phenol stream11to form second combined stream23, which is flowed into crude phenol distillation column101.

According to embodiments of the invention, as shown in block505, processing of method500includes treating second top stream24in hydro-extraction unit103to form second product stream29comprising primarily phenol and second recycle stream28comprising phenol, acetone, and alpha methyl styrene. At block505, hydro-extraction unit103can include a hydro-extraction column. The hydro-extraction column may be operated at an extraction temperature of 100 to 250° C. and extraction pressure of 0.4 to 2.0 bar. Hydro-extraction unit103at block505may be operated using a solvent comprising water, hydroxyl acetone, and 2-methyl benzyl furan. In embodiments of the invention, second recycle stream28is flowed to a phenol-acetone separation column. Second product stream29may comprise 65% to 95 wt. % phenol and all ranges and values there between including ranges of 65 to 70 wt. %, 70 to 75 wt. %, 75 to 80 wt. %, 80 to 85 wt. %, 85 to 90 wt. %, and 90 to 95 wt. %.

According to embodiments of the invention, as shown in block601of method600, processing of method600includes distilling crude phenol stream11in crude phenol distillation column101to form third top stream34comprising primarily phenol, and third bottom stream35comprising phenol and phenol tar. In embodiments of the invention, third top stream34comprises 85 to 99 wt. % phenol. In embodiments of the invention, at block601, crude phenol distillation column101is operated at an overhead temperature range of 40 to 150° C. and a bottom temperature range of 80 to 250° C. Crude phenol distillation column101may be operated at an operating pressure in a range of 0.2 to 0.8 bar and all ranges and values there between including ranges of 0.2 to 0.3 bar, 0.3 to 0.4 bar, 0.4 to 0.5 bar, 0.5 to 0.6 bar, 0.6 to bar, and 0.7 to 0.8 bar.

According to embodiments of the invention, as shown in block602, processing

of method600includes distilling bisphenol-A purge stream12and third bottom stream35in bisphenol-A-phenol distillation column102to form third bisphenol-A column bottom stream37comprising phenol tar and/or bisphenol-A tar, and third intermediate phenol stream36comprising phenol. In embodiments of the invention, at block602, bisphenol-A-phenol distillation column102is operated at an overhead temperature of 80 to 120° C., a bottom temperature of 150 to 200° C., and an operating pressure of 0.2 to 0.8 bar. Third bisphenol-A column bottom stream37may comprise 2 to 15 wt. % phenol, and 85 to 98 wt. % combined phenol tar and bisphenol-A tar. Third intermediate phenol stream36may comprise 60 to 98 wt. % phenol.

According to embodiments of the invention, as shown in block603, processing

of method600includes subjecting, in cracking unit104, third bisphenol-A column bottom stream37to reaction conditions sufficient to crack the phenol tar and/or the bisphenol-A tar to produce additional phenol. The step of subjecting at block603may further produce tars, and/or AMS. In embodiments of the invention, the subjecting at block603may include contacting third bisphenol-A column bottom stream37with an acidic catalyst comprising sulfonic acid, hydrochloric acid, nitric acid, or combinations thereof. In embodiments of the invention, at block603, cracking unit104is operated at an operating temperature of 80 to 300° C. and a pressure of 0.5 to 2 bar. According to embodiments of the invention, as shown in block604, processing of method600may include combining third intermediate phenol stream36with third top stream34to form third combined stream33.

According to embodiments of the invention, as shown in block605, processing of method600includes treating third combined stream33in hydro-extraction unit103to form third product stream39comprising primarily phenol and third recycle stream38comprising phenol, acetone, and alpha-methyl styrene. Third product stream39may include 60 to 95 wt. % phenol. At block605, hydro-extraction unit103can include a hydro-extraction column. The hydro-extraction column may be operated at an extraction temperature of 100 to 250° C. and extraction pressure of 0.4 to 2.0 bar. Hydro-extraction unit103at block605may be operated using a solvent comprising water, hydroxyl acetone, and 2-methyl benzyl furan. In embodiments of the invention, third recycle stream38is flowed to a phenol-acetone separation column.

Although embodiments of the present invention have been described with reference to blocks ofFIGS.2A,2B, and2Cshould be appreciated that operation of the present invention is not limited to the particular blocks and/or the particular order of the blocks illustrated inFIGS.2A,2B, and2C. Accordingly, embodiments of the invention may provide functionality as described herein using various blocks in a sequence different than that ofFIGS.2A,2B, and2C.

The systems and processes described herein can also include various equipment that is not shown and is known to one of skill in the art of chemical processing. For example, some controllers, piping, computers, valves, pumps, heaters, thermocouples, pressure indicators, mixers, heat exchangers, and the like may not be shown.

As part of the disclosure of the present invention, specific examples are included below. The examples are for illustrative purposes only and are not intended to limit the invention. Those of ordinary skill in the art will readily recognize parameters that can be changed or modified to yield essentially the same results.

EXAMPLES

Simulations of the systems as shown inFIGS.1A(system100) and1B (system200) were run in ASPEN HYSIS version10platform. The operating parameters for system100are shown in Table 1.

Tables 1-4 show the comparative examples of integrated configuration (FIG.1A) and non-integrated configuration400(FIG.3). Under the same operating conditions of columns101,102,103and104, configuration1A (column101and102) is more effective for recovering phenol, leading to lesser phenol at the inlet of the cracker.

In the context of the present invention, at least the following 20 embodiments

are described. Embodiment 1 is a method of recovering phenol. The method includes concurrently processing, in a phenol recovery system, (i) a crude phenol stream containing phenol and phenol tar and (ii) a bisphenol-A purge stream containing phenol and bisphenol-A tar to produce a first product stream containing 60 to 95 wt. % phenol, wherein the phenol recovery system includes a crude phenol distillation column and a bisphenol-A-phenol distillation column and the processing includes distilling a bottom stream from the crude phenol distillation column in the bisphenol-A-phenol distillation column. Embodiment 2 is the method of embodiment 1, wherein the bottom stream from the crude phenol distillation column contains 2 to 15 wt. % phenol, and 85 to 98 wt. % combined phenol tar and bisphenol-A tar. Embodiment 3 is the method of embodiment 2, wherein the distilling of the bottom stream produces a bisphenol-A-phenol distillation column bottom stream containing primarily phenol tar and bisphenol-A tar, collectively. Embodiment 4 is the method of embodiment 3, further including subjecting the bisphenol-A column bottom stream to reaction conditions sufficient to crack the phenol tar and/or the bisphenol-A tar to produce additional phenol. Embodiment 5 is the method of embodiment 4, wherein the subjecting step further produces ct-methylstyrene. Embodiment 6 is the method of either of embodiments 4 or 5, wherein the reaction conditions for the subjecting step include a reaction temperature of 100 to 250° C. and a reaction pressure of 0.2 to 1.5 bar. Embodiment 7 is the method of any of embodiments 4 to 6, wherein the subjecting step includes contacting the bisphenol column bottom stream with an acidic catalyst selected from the group consisting of sulfonic acid, hydrochloric acid, nitric acid, and combinations thereof. Embodiment 8 is the method of any of embodiments 1 to 7, wherein the phenol tar contains acetophenone, dimethylbenzylalcohol, o,p-cumylphenol, alphamethylstyrene dimer, phenol, or combinations thereof. Embodiment 9 is the method of any of embodiments 1 to 8, wherein the bisphenol-A tar contains p,p-bisphenol-A, o,p-bisphenol-A, isopropenyl phenol, Chroman, BPX, isopropenyl phenol dimers, spirobi, or combinations thereof. Embodiment 10 is the method of any of embodiments 1 to 9, wherein the processing includes combining the crude phenol stream and the bisphenol-A purge stream to form a feed stream. The method further includes distilling the feed stream in the crude phenol distillation column to form a first top stream containing 85 to 99 wt. % phenol and a first bottom stream containing phenol, combined phenol tar and bisphenol-A tar, wherein the first distilling of the bottom stream in the bisphenol-A phenol distillation column further produces an intermediate phenol stream containing phenol. Embodiment 11 is the method of embodiment 10, wherein the processing further includes distilling the intermediate phenol stream in the crude phenol distillation column to produce additional phenol in the first top stream. Embodiment 12 is the method of either of embodiments 10 or 11, wherein the processing further includes treating the first top stream in a hydro-extraction unit to produce the first product stream containing 60 to 95 wt. % phenol and a recycle stream containing 0.5 to 2 wt. % phenol. Embodiment 13 is the method of any of embodiments 1 to 9, wherein the processing includes distilling the crude phenol stream in the crude phenol distillation column to form a second top stream containing 85 to 99 wt. % phenol and a second bottom stream from the crude phenol distillation column containing phenol, phenol tar, and bisphenol-A tar. The method further includes distilling the bisphenol-A purge stream and the bottom stream in the bisphenol-A-phenol distillation column to form a second bisphenol column bottom stream, and a second intermediate phenol stream containing phenol. Embodiment 14 is the method of embodiment 13, wherein the processing further includes combining at least a portion of the second intermediate phenol stream with the crude phenol stream to form a second combined stream. The method further includes distilling the second combined stream in the crude phenol distillation column. Embodiment 15 is the method of either of embodiments 13 or 14, wherein the processing further includes combining at least a portion of the second intermediate phenol stream with the second top stream to form a third combined stream containing primarily phenol. The method also includes processing the third combined stream in a hydro-extraction unit to form the first product stream containing 60 to 95 wt. % phenol and a recycle stream containing 0.5 to 2 wt. % phenol. Embodiment 16 is the method of any of embodiments 13 to 15, wherein the hydro-extraction unit is operated at an extraction temperature of 100 to 250° C. and an extraction pressure of 0.4 to 2 bar. Embodiment 17 is the method of any of embodiments 13 to 16, wherein the crude phenol distillation column is operated at an overhead temperature range of 120 to 150° C., a reboiler range of 180 to 220° C., and an operating pressure of 0.1 to 0.5 bar. Embodiment 18 is the method of any of embodiments 13 to 17, wherein the bisphenol-A-phenol distillation column is operated at an overhead temperature range of 80 to 120° C., a reboiler range of 150 to 200° C., and an operating pressure of 0.1 to 0.7 bar. Embodiment 19 is the method of any of embodiments 1 to 18, wherein the crude phenol stream is produced by separating an effluent of a cumene based phenol production process. Embodiment 20 is the method of any of embodiments 1 to 19, wherein the bisphenol-A purge stream includes a bisphenol-A dry mother liquor purge stream generated by crystallization of bisphenol-A from an effluent of a bisphenol-A synthesis reactor.