Multi-system circulating device and method for crude phenol separation

Abstract

The invention discloses a multi-system circulating device for crude phenol separation in the field of deep processing of coal tar. The de-weighting unit is connected with the dehydration unit through a pipeline; the first rectification unit is connected with the heavy component removal unit through a pipeline; the second rectification unit is connected with the first rectification unit through a pipeline; the third rectification unit is connected with the second rectification unit through a pipeline; the fourth rectification unit is connected with the third rectification unit through a pipeline; the fifth rectification unit is connected with the fourth rectification unit through a pipeline; the recovery unit is connected with the fifth rectification unit through a pipeline; the circulating assembly returns the high-concentration raw material to be rectified again; and a separation method; the system has the beneficial effects that the crude phenol can be separated more thoroughly by arranging the multiple stages of rectification units, the concentration of a mixture in the system can be monitored by arranging the circulating unit, and the mixture is returned according to the concentration to be rectified again, so that the output rate and the separation precision are improved.

Description

Technical Field

[0001] This invention relates to the field of deep processing of coal tar, specifically to a multi-system circulating device and method for separating crude phenols. Background Technology

[0002] Crude phenols are a key byproduct in the deep processing of coal tar, and their main components are a mixture of polyphenols such as phenol and cresols (o-cresol, m-cresol, and p-cresol). These high-purity phenolic products (especially phenol, o-cresol, and m-p-cresol) are important raw materials for the synthesis of high-performance resins, pharmaceuticals, pesticides, dyes, and antioxidants, and have high market demand and economic value.

[0003] Currently, the industrial separation of single phenolic components from crude phenol mainly relies on conventional distillation techniques. However, due to the complex composition of crude phenol and the very close boiling points of phenol, m-cresol, and p-cresol, conventional separation methods suffer from limitations such as low separation efficiency, insufficient product purity, and discontinuous processes. Obtaining high-purity phenol and o-cresol products typically involves high energy consumption and operating costs. Furthermore, existing processes often lack optimized integration between unit operations, failing to form an efficient and coherent separation sequence, resulting in problems such as large material recycling volumes and yield losses.

[0004] Therefore, we propose a multi-system circulating device and method for crude phenol separation. Summary of the Invention

[0005] To address the aforementioned shortcomings of the prior art, the present invention provides a multi-system circulating device and method for crude phenol separation.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A multi-system circulating device for crude phenol separation includes: a dehydration unit for pre-treating the raw material by dehydration; and a deweighting unit connected to the dehydration unit via a pipeline for deweighting the dehydrated raw material. The first distillation unit, connected to the deweighting unit via pipeline, distills and collects phenol from the deweighted feedstock. The second distillation unit, connected to the first distillation unit via pipeline, removes residual phenol from the feedstock discharged from the first distillation unit. The third distillation unit, connected to the second distillation unit via pipeline, distills and collects o-cresol from the feedstock discharged from the second distillation unit. The fourth distillation unit, connected to the third distillation unit via pipeline, removes residual o-cresol from the feedstock discharged from the third distillation unit. The fifth distillation unit, connected to the fourth distillation unit via pipeline, distills and collects cresol from the feedstock discharged from the fourth distillation unit. The recovery unit, connected to the fifth distillation unit via pipeline, recovers low-boiling-point phenols from the feedstock discharged from the fifth distillation unit. The circulation unit is located between the feed ends of the fourth and first distillation units, and between the feed ends of the recovery unit and the third distillation unit. The circulation assembly is used to return high-concentration feedstock for re-distillation.

[0007] By setting up multiple distillation units to perform stepwise distillation separation of crude phenol, the separation of crude phenol can be more thorough. In addition, the circulation unit can be set up so that if the concentration of a certain component of the raw material entering the subsequent distillation unit is incorrect during the separation process, the raw material can be sent back to the previous distillation unit for re-distillation. This can further improve the separation accuracy of crude phenol, increase the yield and purity of by-products, and prevent the accumulation of undesirable components in the system by setting up the circulation unit, thus optimizing the processing load and efficiency of each distillation unit.

[0008] Further defined, the dehydration unit includes a dehydration tower, a first condenser, a first reflux tank, a first centrifugal pump, a second centrifugal pump, and a first reboiler; The feed end of the first condenser is connected to the top of the dehydration tower via a pipe, and the discharge end is connected to the top of the first reflux tank via a pipe. The bottom end of the first reflux tank is connected to the upper part of the dehydration tower via the first centrifugal pump and the first reflux pipe. A branch pipe for wastewater discharge is connected to the first reflux pipe. The bottom of the dehydration tower is connected to the de-weighting unit via the second centrifugal pump. The feed end of the first reboiler is connected to the pipe between the dehydration tower and the second centrifugal pump, and the discharge end is connected to the lower part of the dehydration tower. The deweight removal unit includes a deweight removal tower, a second condenser, a second reflux tank, a third centrifugal pump, a fourth centrifugal pump, and a second reboiler; The bottom of the dehydration tower is connected to the middle of the de-heavy distillation tower via a second centrifugal pump. The feed end of the second condenser is connected to the top of the dehydration tower via a pipe, and the discharge end is connected to the top of the second reflux tank via a pipe. The bottom of the second reflux tank is connected to the upper part of the de-heavy distillation tower via a third centrifugal pump and a second reflux pipe. The bottom of the de-heavy distillation tower is connected to a pipe for waste discharge via a fourth centrifugal pump. The feed end of the second reboiler is connected to the pipe between the de-heavy distillation tower and the fourth centrifugal pump, and the discharge end is connected to the lower part of the de-heavy distillation tower. The second reflux pipe is connected to the first distillation unit via a branch pipe.

[0009] Further specified, the first distillation unit includes a phenol column, a third condenser, a third reflux tank, a fifth centrifugal pump, a sixth centrifugal pump, and a third reboiler; The second reflux pipe is connected to the middle of the phenol tower via a branch pipe. The feed end of the third condenser is connected to the top of the phenol tower via a pipe, and the discharge end is connected to the top of the third reflux tank via a pipe. The bottom of the third reflux tank is connected to the upper part of the phenol tower via the fifth centrifugal pump and the third reflux pipe. A branch pipe for collecting phenol products is connected to the third reflux pipe. The bottom of the phenol tower is connected to the second distillation unit via the sixth centrifugal pump. The feed end of the third reboiler is connected to the pipe between the phenol tower and the sixth centrifugal pump, and the discharge end is connected to the lower part of the phenol tower.

[0010] Further specifying, the second distillation unit includes an o-cresol removal column, a fourth condenser, a fourth reflux tank, a seventh centrifugal pump, an eighth centrifugal pump, and a fourth reboiler; The pipe at the discharge end of the sixth centrifugal pump is connected to the middle of the o-cresol light removal tower. The feed end of the fourth condenser is connected to the top of the o-cresol light removal tower via a pipe, and the discharge end is connected to the top of the fourth reflux tank via a pipe. The bottom of the fourth reflux tank is connected to the upper part of the o-cresol light removal tower via the seventh centrifugal pump and the fourth reflux pipe. A branch pipe for the collection of the phenol and o-cresol mixture is also connected to the fourth reflux pipe. The bottom of the o-cresol light removal tower is connected to the third distillation unit via the eighth centrifugal pump. The feed end of the fourth reboiler is connected to the pipe between the eighth centrifugal pump and the o-cresol light removal tower, and the discharge end is connected to the lower part of the o-cresol light removal tower. The branch pipes of the fourth reflux pipe and the second reflux pipe are connected via the first reflux pipe.

[0011] Further specifying, the third distillation unit includes an o-cresol column, a fifth condenser, a fifth reflux tank, a ninth centrifugal pump, a tenth centrifugal pump, and a fifth reboiler; The discharge end of the eighth centrifugal pump is connected to the middle of the o-cresol tower via a pipeline. The feed end of the fifth condenser is connected to the top of the o-cresol tower via a pipeline, and the discharge end is connected to the top of the fifth reflux tank via a pipeline. The bottom of the fifth reflux tank is connected to the upper part of the o-cresol tower via the ninth centrifugal pump and the fifth reflux pipe. A branch pipe for o-cresol product collection is also connected to the fifth reflux pipe. The bottom of the o-cresol tower is connected to the fourth distillation unit via the tenth centrifugal pump. The feed end of the fourth reboiler is connected to the pipeline between the tenth centrifugal pump and the o-cresol tower, and the discharge end is connected to the lower part of the o-cresol tower.

[0012] Further specifying, the fourth distillation unit includes a cresol removal column, a sixth condenser, a sixth reflux tank, an eleventh centrifugal pump, a twelfth centrifugal pump, and a sixth reboiler; The discharge end of the tenth centrifugal pump is connected to the middle of the cresol light removal tower via a pipeline. The feed end of the sixth condenser is connected to the top of the cresol light removal tower via a pipeline, and the discharge end is connected to the top of the sixth reflux tank via a pipeline. The bottom of the sixth reflux tank is connected to the upper part of the cresol light removal tower via the eleventh centrifugal pump and the sixth reflux pipe. A branch pipe for the collection of o-cresol and cresol mixture and a second reflux pipe are connected to the sixth reflux pipe. The end of the second reflux pipe is connected to the feed pipeline of the o-cresol tower. The bottom of the cresol light removal tower is connected to the fifth distillation unit via the twelfth centrifugal pump. The feed end of the sixth reboiler is connected to the pipeline between the twelfth centrifugal pump and the cresol light removal tower, and the discharge end is connected to the lower part of the cresol light removal tower.

[0013] Further specifying, the fifth distillation unit includes a cresol tower, a seventh condenser, a seventh reflux tank, a thirteenth centrifugal pump, a fourteenth centrifugal pump, and a seventh reboiler; The discharge end of the twelfth centrifugal pump is connected to the middle of the cresol tower via a pipeline. The feed end of the seventh condenser is connected to the top of the cresol tower via a pipeline, and the discharge end is connected to the top of the seventh reflux tank via a pipeline. The bottom of the seventh reflux tank is connected to the upper part of the cresol tower via the thirteenth centrifugal pump and the seventh reflux pipe. The seventh reflux pipe also has a branch pipe for cresol product collection. The bottom of the cresol tower is connected to the recovery unit via the fourteenth centrifugal pump. The feed end of the seventh reboiler is connected to the pipeline between the fourteenth centrifugal pump and the cresol tower, and the discharge end is connected to the lower part of the cresol tower.

[0014] Further defined, the recovery unit includes a recovery tower, an eighth condenser, an eighth reflux tank, a fifteenth centrifugal pump, a sixteenth centrifugal pump, and an eighth reboiler; The discharge end of the fourteenth centrifugal pump is connected to the middle of the recovery tower via a pipeline. The feed end of the eighth condenser is connected to the top of the recovery tower via a pipeline, and the discharge end is connected to the top of the eighth reflux tank via a pipeline. The bottom of the eighth reflux tank is connected to the upper part of the recovery tower via the fifteenth centrifugal pump and the eighth reflux pipe. The eighth reflux pipe and the feed end of the cresol tower are connected via the third reflux pipe. The bottom of the recovery tower is connected to the recovery pipe via the sixteenth centrifugal pump. The feed end of the eighth reboiler is connected to the pipeline between the sixteenth centrifugal pump and the recovery tower, and the discharge end is connected to the lower part of the recovery tower.

[0015] Further defined, the circulation unit includes a first circulation pipe, a first concentration monitor, a second circulation pipe, a second concentration monitor, a first electrically controlled valve, and a second electrically controlled valve; the two ends of the first circulation pipe are respectively connected to the pipe at the discharge end of the tenth centrifugal pump and the branch pipe of the second reflux pipe; the first concentration monitor is located on the pipe at the discharge end of the tenth centrifugal pump and the first circulation pipe; the first electrically controlled valve is located on the first circulation pipe; the two ends of the second circulation pipe are respectively connected to the pipe at the discharge end of the fourteenth centrifugal pump and the pipe at the discharge end of the eighth centrifugal pump; the second concentration monitor is located on the pipe at the discharge end of the fourteenth centrifugal pump and the second circulation pipe; the second electrically controlled valve is located on the second circulation pipe; the first concentration monitor, the second concentration monitor, the first electrically controlled valve, and the second electrically controlled valve are electrically connected to the controller of the entire system.

[0016] This configuration of a first and a second concentration monitor allows the first monitor to track the phenol concentration in the feed delivered by the tenth centrifugal pump. Based on the phenol concentration, the opening of the first electrically controlled valve is adjusted to return a portion of the feed to the phenol tower for further distillation. The second concentration monitor tracks the o-cresol concentration in the feed delivered by the fourteenth centrifugal pump. Based on the o-cresol concentration, the opening of the second electrically controlled valve is adjusted to return a portion of the feed to the o-cresol tower for further distillation. This effectively improves the purity and yield of phenol, o-cresol, and cresol products, increases the product qualification rate, reduces the load on the o-cresol and cresol towers, and simultaneously achieves energy conservation and consumption reduction.

[0017] A separation method, employing the aforementioned multi-system circulation device for crude phenol separation, includes the following steps: S1. The crude phenol feedstock first enters the dehydration tower for dehydration pretreatment. The phenol-containing wastewater after distillation in the dehydration tower is condensed by the first condenser through the pipe at the top of the tower and flows into the first reflux tank. The first reflux tank sends part of the phenol-containing wastewater back to the top of the dehydration tower for reflux through the first centrifugal pump, and the other part is collected through the branch pipe. Part of the bottom fraction of the dehydration tower is refluxed through the first reboiler, and the other part is sent to the middle of the de-heavy distillation tower through the second centrifugal pump. The de-heavy distillation tower performs de-heavy pretreatment on the crude phenol feedstock. Part of the heavy distillate at the bottom of the de-heavy distillation tower is refluxed by the second reboiler, and the other part is sent out of the system for storage by the fourth centrifugal pump. The top fraction of the de-heavy distillation tower flows into the second reflux tank through the second condenser, and then the third centrifugal pump sends part of the light phenolic compounds to the top of the tower for reflux, and the other part to the phenol tower. S2. The raw material entering the phenol column: the phenol fraction at the top of the phenol column after rectification passes through the third condenser and enters the third reflux tank. Then, a portion is sent to the top of the column for reflux by the fifth centrifugal pump, and the other portion is collected through the branch pipe. A portion of the bottom fraction of the phenol column is refluxed through the third reboiler, and the other portion is sent to the o-cresol removal column by the sixth centrifugal pump. The top fraction after rectification in the o-cresol removal column is condensed by the fourth condenser to obtain a mixture of phenol and o-cresol. After entering the fourth reflux tank, the mixture is divided into three parts by the seventh centrifugal pump. A portion is sent to the top of the o-cresol removal column for reflux, another portion is collected, and the third portion is sent to the phenol column for redistribution. A portion of the bottom fraction of the o-cresol removal column is refluxed through the fourth reboiler, and the other portion is sent to the o-cresol column by the eighth centrifugal pump. S3. The raw material entering the o-cresol column, after rectification, is condensed in the fifth condenser to obtain o-cresol. It then passes through the fifth reflux tank, and a portion is sent back to the top of the o-cresol column for reflux via the ninth centrifugal pump, while the other portion is collected through a branch pipe. A portion of the bottom fraction of the o-cresol column is refluxed in the fifth reboiler, and the other portion is sent out by the tenth centrifugal pump. The first concentration monitor continuously monitors the phenol concentration in the raw material. The system controller controls the opening of the first electrically controlled valve based on the phenol concentration; the higher the phenol concentration, the larger the opening of the first electrically controlled valve. A centrifugal pump returns a portion of the raw material to the phenol column for further distillation, while the other portion is sent to the cresol light-light-removal column. The raw material entering the cresol light-light-removal column, after distillation, is condensed in the sixth condenser to obtain a mixture of o-cresol and cresol. The mixture is then passed through the sixth reflux tank. An eleventh centrifugal pump sends a portion of the mixture back to the cresol light-light-removal column for reflux, collects a portion, and sends a portion to the o-cresol column for further distillation. A portion of the bottom fraction of the cresol light-light-removal column is refluxed through the sixth reboiler, while the other portion is sent to the cresol column by the twelfth centrifugal pump. S4. The raw material entering the cresol column, after rectification, is condensed in the seventh condenser to obtain cresol. The cresol passes through the seventh reflux tank, and then a portion of it is sent back to the top of the cresol column for reflux by the thirteenth centrifugal pump, while the other portion is collected through a branch pipe. A portion of the bottom fraction of the cresol column is refluxed in the seventh reboiler, and the other portion is sent out by the fourteenth centrifugal pump. The second concentration monitor tracks the concentration of o-cresol in the raw material sent out by the fourteenth centrifugal pump. The system controller controls the opening of the second electrically controlled valve based on the o-cresol concentration; the higher the o-cresol concentration, the larger the opening of the second electrically controlled valve. The larger the opening, the more the fourteenth centrifugal pump sends a portion of the bottom fraction back to the o-cresol column for further distillation, and another portion to the recovery column. The raw material entering the recovery column, after being distilled in the recovery column, is condensed by the eighth condenser to obtain a mixture of cresol, phenol, etc. The mixture passes through the eighth reflux tank, and then the fifteenth centrifugal pump sends a portion of the mixture to the top of the recovery column for reflux, and another portion is sent back to the cresol column for further distillation through the third reflux pipe. A portion of the bottom fraction of the recovery column is refluxed through the eighth reboiler, and the other portion is sent out by the sixteenth centrifugal pump for storage.

[0018] The beneficial effects of this invention are as follows: by setting up a multi-stage distillation unit, crude phenol can be separated more thoroughly. Furthermore, by setting up a circulation unit in this way, the concentration of the mixture in the system can be monitored, and the mixture can be sent back for re-distillation based on the concentration, thereby improving the yield and separation accuracy. Attached Figure Description

[0019] Figure 1 This is a diagram showing the connection relationship between the four units in the first half of this invention; Figure 2 This is a diagram showing the connection relationship between the four units in the latter half of this invention.

[0020] The symbols for each component are as follows: Dehydration Unit 1, Dehydration Tower 11, First Condenser 12, First Reflux Tank 13, First Centrifugal Pump 14, Second Centrifugal Pump 15, First Reboiler 16, First Reflux Pipe 17; De-weighting Unit 2, De-weighting Tower 21, Second Condenser 22, Second Reflux Tank 23, Third Centrifugal Pump 24, Fourth Centrifugal Pump 25, Second Reboiler 26, Second Reflux Pipe 27; First Distillation Unit 3, Phenol Tower 31, Third Condenser 32, Third Reflux Tank 33, Fifth Centrifugal Pump 34, Sixth Centrifugal Pump 35, Third Reboiler 36, Third Reflux Pipe 37; Second Distillation Unit 4, o-Cresol Light Removal Tower 41, Fourth Condenser 42, Fourth Reflux Tank 43, Seventh Centrifugal Pump 44, Eighth Centrifugal Pump 45, Fourth Reboiler 46, Fourth Reflux Pipe 47, First Reflux Pipe 48; Third Distillation Unit 5, o-Cresol Tower 51, Fifth Condenser 52, Fifth Reflux Tank 53, Ninth Centrifugal Pump 5 4. Tenth centrifugal pump 55, Fifth reboiler 56, Fifth reflux pipe 57, Fourth distillation unit 6, Cresol light removal tower 61, Sixth condenser 62, Sixth reflux tank 63, Eleventh centrifugal pump 64, Twelfth centrifugal pump 65, Sixth reboiler 66, Sixth reflux pipe 67, Second reflux pipe 68, Fifth distillation unit 7, Cresol tower 71, Seventh condenser 72, Seventh reflux tank 73, Thirteenth centrifugal pump 74, Fourteenth centrifugal pump 75, Seventh reboiler 76, Seventh reflux pipe 77, Recovery unit 8, Recovery tower 81, Eighth condenser 82, Eighth reflux tank 83, Fifteenth centrifugal pump 84, Sixteenth centrifugal pump 85, Eighth reboiler 86, Eighth reflux pipe 87, Third reflux pipe 88, Circulation unit 9, First circulation pipe 91, First concentration monitor 92, Second circulation pipe 93, Second concentration monitor 94, First electric control valve 95, Second electric control valve 96. Detailed Implementation

[0021] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0022] Example: like Figure 1 and Figure 2 As shown, a multi-system circulating device for crude phenol separation includes a dehydration unit 1, a de-gravity removal unit 2, a first distillation unit 3, a second distillation unit 4, a third distillation unit 5, a fourth distillation unit 6, a fifth distillation unit 7, a recovery unit 8, and a circulation unit 9. The dehydration unit 1 is used for dehydration pretreatment of raw materials; the dehydration unit 1 includes a dehydration tower 11, a first condenser 12, a first reflux tank 13, a first centrifugal pump 14, a second centrifugal pump 15, and a first reboiler 16; the feed end of the first condenser 12 is connected to the top of the dehydration tower 11 through a pipe, and the discharge end is connected to the top of the first reflux tank 13 through a pipe; the bottom end of the first reflux tank 13 is connected to the upper part of the dehydration tower 11 through the first centrifugal pump 14 and the first reflux pipe 17; a branch pipe for wastewater discharge is connected to the first reflux pipe 17; the bottom of the dehydration tower 11 is connected to the de-weighting unit 2 through the second centrifugal pump 15; the feed end of the first reboiler 16 is connected to the pipe between the dehydration tower 11 and the second centrifugal pump 15, and the discharge end is connected to the lower part of the dehydration tower 11; The deweighting unit 2 is used to deweight the dehydrated raw material. The deweighting unit 2 includes a deweighting tower 21, a second condenser 22, a second reflux tank 23, a third centrifugal pump 24, a fourth centrifugal pump 25, and a second reboiler 26. The bottom of the dehydration tower 11 is connected to the middle of the deweighting tower 21 through the second centrifugal pump 15. The feed end of the second condenser 22 is connected to the top of the dehydration tower 11 through a pipe, and the discharge end is connected to the top of the second reflux tank 23 through a pipe. The bottom of the second reflux tank 23 is connected to the upper part of the deweighting tower 21 through the third centrifugal pump 24 and the second reflux pipe 27. The bottom of the deweighting tower 21 is connected to a pipe for waste discharge through the fourth centrifugal pump 25. The feed end of the second reboiler 26 is connected to the pipe between the deweighting tower 21 and the fourth centrifugal pump 25, and the discharge end is connected to the lower part of the deweighting tower 21. The second reflux pipe 27 is connected to the first distillation unit 3 through a branch pipe. The first distillation unit 3 is used to distill and extract phenol from the deweighted raw material. The first distillation unit 3 includes a phenol tower 31, a third condenser 32, a third reflux tank 33, a fifth centrifugal pump 34, a sixth centrifugal pump 35, and a third reboiler 36. The second reflux pipe 27 is connected to the middle of the phenol tower 31 through a branch pipe. The feed end of the third condenser 32 is connected to the top of the phenol tower 31 through a pipe, and the discharge end is connected to the top of the third reflux tank 33 through a pipe. The bottom of the third reflux tank 33 is connected to the upper part of the phenol tower 31 through the fifth centrifugal pump 34 and the third reflux pipe 37. A branch pipe for phenol product extraction is connected to the third reflux pipe 37. The bottom of the phenol tower 31 is connected to the second distillation unit 4 through the sixth centrifugal pump 35. The feed end of the third reboiler 36 is connected to the pipe between the phenol tower 31 and the sixth centrifugal pump 35, and the discharge end is connected to the lower part of the phenol tower 31. The second distillation unit 4 is used to remove residual phenol from the feed discharged from the first distillation unit 3. The second distillation unit 4 includes an o-cresol removal tower 41, a fourth condenser 42, a fourth reflux tank 43, a seventh centrifugal pump 44, an eighth centrifugal pump 45, and a fourth reboiler 46. The outlet pipe of the sixth centrifugal pump 35 is connected to the middle of the o-cresol removal tower 41. The inlet of the fourth condenser 42 is connected to the top of the o-cresol removal tower 41 through a pipe, and the outlet is connected to the top of the fourth reflux tank 43 through a pipe. The bottom of the fourth reflux tank 43 is connected to the fourth reflux tank 43. The upper part of the o-cresol light removal tower 41 is connected to the seventh centrifugal pump 44 and the fourth reflux pipe 47. The fourth reflux pipe 47 also has a branch pipe for the collection of the mixed product of phenol and o-cresol. The bottom of the o-cresol light removal tower 41 is connected to the third distillation unit 5 through the eighth centrifugal pump 45. The feed end of the fourth reboiler 46 is connected to the pipe between the eighth centrifugal pump 45 and the o-cresol light removal tower 41, and the discharge end is connected to the lower part of the o-cresol light removal tower 41. The branch pipes of the fourth reflux pipe 47 and the second reflux pipe 27 are connected through the first reflux pipe 48. The third distillation unit 5 is used to distill and extract o-cresol from the feed discharged from the second distillation unit 4. The third distillation unit 5 includes an o-cresol column 51, a fifth condenser 52, a fifth reflux tank 53, a ninth centrifugal pump 54, a tenth centrifugal pump 55, and a fifth reboiler 56. The discharge end of the eighth centrifugal pump 45 is connected to the middle of the o-cresol column 51 via a pipeline, and the feed end of the fifth condenser 52 is connected to the top of the o-cresol column 51 via a pipeline, and the discharge end of the fifth condenser 52 is connected to the middle of the second centrifugal pump 44 via a pipeline. The top of the fifth reflux tank 53 and the bottom of the fifth reflux tank 53 are connected to the upper part of the o-cresol tower 51 through the ninth centrifugal pump 54 and the fifth reflux pipe 57. A branch pipe for o-cresol product collection is also connected to the fifth reflux pipe 57. The bottom of the o-cresol tower 51 is connected to the fourth distillation unit 6 through the tenth centrifugal pump 55. The feed end of the fourth reboiler 46 is connected to the pipe between the tenth centrifugal pump 55 and the o-cresol tower 51, and the discharge end is connected to the lower part of the o-cresol tower 51. The fourth distillation unit 6 is used to remove residual o-cresol from the feed discharged from the third distillation unit 5. The fourth distillation unit 6 includes a cresol removal tower 61, a sixth condenser 62, a sixth reflux tank 63, an eleventh centrifugal pump 64, a twelfth centrifugal pump 65, and a sixth reboiler 66. The discharge end of the tenth centrifugal pump 65 is connected to the middle of the cresol removal tower 61 via a pipeline. The feed end of the sixth condenser 62 is connected to the top of the cresol removal tower 61 via a pipeline, and its discharge end is connected to the top of the sixth reflux tank 63 via a pipeline. The bottom of the sixth reflux tank 63... The unit is connected to the upper part of the cresol light removal tower 61 via the eleventh centrifugal pump 64 and the sixth reflux pipe 67. The sixth reflux pipe 67 has a branch pipe for the collection of o-cresol and cresol mixture and a second reflux pipe 68. The end of the second reflux pipe 68 is connected to the feed pipe of the o-cresol tower 51. The bottom of the cresol light removal tower 61 is connected to the fifth distillation unit 7 via the twelfth centrifugal pump 65. The feed end of the sixth reboiler 66 is connected to the pipe between the twelfth centrifugal pump 65 and the cresol light removal tower 61, and the discharge end is connected to the lower part of the cresol light removal tower 61. The fifth distillation unit 7 is used to distill and extract cresol from the feed material discharged from the fourth distillation unit 6. The fifth distillation unit 7 includes a cresol tower 71, a seventh condenser 72, a seventh reflux tank 73, a thirteenth centrifugal pump 74, a fourteenth centrifugal pump 75, and a seventh reboiler 76. The discharge end of the twelfth centrifugal pump 65 is connected to the middle of the cresol tower 71 through a pipeline. The feed end of the seventh condenser 72 is connected to the top of the cresol tower 71 through a pipeline, and the discharge end is connected to the top of the seventh reflux tank 73 through a pipeline. The bottom of the seventh reflux tank 73 is connected to the upper part of the cresol tower 71 through the thirteenth centrifugal pump 74 and the seventh reflux pipe 77. The seventh reflux pipe 77 also has a branch pipe for extracting cresol products. The bottom of the cresol tower 71 is connected to the recovery unit 8 through the fourteenth centrifugal pump 75. The feed end of the seventh reboiler 76 is connected to the pipeline between the fourteenth centrifugal pump 75 and the cresol tower 71, and the discharge end is connected to the lower part of the cresol tower 71. Recovery unit 8 is used to recover low-boiling-point phenols from the feed discharged from fifth distillation unit 7. Recovery unit 8 includes recovery tower 81, eighth condenser 82, eighth reflux tank 83, fifteenth centrifugal pump 84, sixteenth centrifugal pump 85, and eighth reboiler 86. The discharge end of fourteenth centrifugal pump 75 is connected to the middle of recovery tower 81 through a pipeline. The feed end of eighth condenser 82 is connected to the top of recovery tower 81 through a pipeline, and the discharge end is connected to the top of eighth reflux tank 83 through a pipeline. The bottom of eighth reflux tank 83 is connected to the upper part of recovery tower 81 through fifteenth centrifugal pump 84 and eighth reflux pipe 87. The feed end of eighth reflux pipe 87 and cresol tower 71 is connected through third reflux pipe 88. The bottom end of recovery tower 81 is connected to recovery pipe through sixteenth centrifugal pump 85. The feed end of eighth reboiler 86 is connected to the pipeline between sixteenth centrifugal pump 85 and recovery tower 81, and the discharge end is connected to the lower part of recovery tower 81. The circulation unit 9 includes a first circulation pipe 91, a first concentration monitor 92, a second circulation pipe 93, a second concentration monitor 94, a first solenoid valve 95, and a second solenoid valve 96. The two ends of the first circulation pipe 91 are respectively connected to the pipe at the discharge end of the tenth centrifugal pump 55 and the branch pipe of the second return pipe 27. The first concentration monitor 92 is located on the pipe at the discharge end of the tenth centrifugal pump 55 and the first circulation pipe 91. The first solenoid valve 95 is located on the first circulation pipe 91. The two ends of the second circulation pipe 93 are respectively connected to the pipe at the discharge end of the fourteenth centrifugal pump 75 and the pipe at the discharge end of the eighth centrifugal pump 45. The second concentration monitor 94 is located on the pipe at the discharge end of the fourteenth centrifugal pump 75 and the second circulation pipe 93. The second solenoid valve 96 is located on the second circulation pipe 93. The first concentration monitor 92, the second concentration monitor 94, the first solenoid valve 95, and the second solenoid valve 96 are electrically connected to the controller of the entire system.

[0023] It should be noted that there are also many electrically controlled valves and system controllers on the pipeline in this application. These electrically controlled valves and system controllers are all mature existing technologies and have not been improved, so they are not described in the application documents.

[0024] This arrangement of multiple distillation units for stepwise distillation separation of crude phenol allows for more thorough separation. The inclusion of a circulation unit 9 enables the return of feedstock to previous units for re-distillation if an incorrect concentration is detected during the separation process. This further improves the separation accuracy of crude phenol, increases the yield and purity of by-products, and prevents the accumulation of undesirable components within the system, optimizing the processing load and efficiency of each distillation unit. The inclusion of a first concentration monitor 92 and a second concentration monitor 94 allows the first concentration monitor 92 to monitor the concentration of crude phenol. The concentration of phenol in the raw material delivered by centrifugal pump 55 is monitored. The opening of the first solenoid valve 95 is adjusted according to the phenol concentration to send part of the raw material back to phenol tower 31 for further distillation. The second concentration monitor 94 can monitor the concentration of o-cresol in the raw material delivered by the fourteenth centrifugal pump 75. The opening of the second solenoid valve 96 is adjusted according to the o-cresol concentration to send part of the raw material back to o-cresol tower 51 for further distillation. This can effectively improve the purity and yield of phenol, o-cresol and cresol products, as well as increase the product qualification rate, reduce the load on o-cresol tower 51 and cresol tower 71, and achieve the purpose of energy saving and consumption reduction.

[0025] A separation method, employing the aforementioned multi-system circulation device for crude phenol separation, includes the following steps: S1. The crude phenol raw material first enters the dehydration tower 11 for dehydration pretreatment. The phenol-containing wastewater after distillation in the dehydration tower 11 is condensed by the first condenser 12 through the pipe at the top of the tower and flows into the first reflux tank 13. The first reflux tank 13 sends part of the phenol-containing wastewater back to the top of the dehydration tower 11 for reflux through the first centrifugal pump 14, and the other part is collected through the branch pipe. Part of the bottom fraction of the dehydration tower 11 is refluxed through the first reboiler 16, and the other part is sent to the middle of the de-heavy tower 21 through the second centrifugal pump 15. The de-heavy tower 21 performs de-heavy pretreatment on the crude phenol raw material. Part of the heavy fraction at the bottom of the de-heavy tower 21 after distillation is refluxed by the second reboiler 26, and the other part is sent out of the system for storage by the fourth centrifugal pump 25. The top fraction of the de-heavy tower 21 flows into the second reflux tank 23 through the second condenser 22, and then sends part of the light phenolic compounds to the top of the tower for reflux and the other part to the phenol tower 31 through the third centrifugal pump 24. S2. The raw material entering the phenol tower 31, the top phenol fraction after distillation in the phenol tower 31, enters the third reflux tank 33 through the third condenser 32, and then a portion is sent to the top reflux tank 33 by the fifth centrifugal pump 34, and the other portion is collected through the branch pipe. A portion of the bottom fraction of the phenol tower 31 is refluxed through the third reboiler 36, and the other portion is sent to the o-cresol removal tower 41 by the sixth centrifugal pump 35. The top fraction after distillation in the o-cresol removal tower 41 is condensed by the fourth condenser 42 to obtain a mixture of phenol and o-cresol. The mixture enters the fourth reflux tank 43, and then the mixture is divided into three parts by the seventh centrifugal pump 44. A portion is sent to the top reflux tank 41 of the o-cresol removal tower, another portion is collected, and the third portion is sent to the phenol tower 31 for redistribution. A portion of the bottom fraction of the o-cresol removal tower 41 is refluxed through the fourth reboiler 46, and the other portion is sent to the o-cresol tower 51 by the eighth centrifugal pump 45. S3. The raw material entering the o-cresol column 51, after rectification in the o-cresol column 51, is condensed by the fifth condenser 52 to obtain o-cresol. It then passes through the fifth reflux tank 53, and a portion is sent back to the top of the o-cresol column 51 for reflux via the ninth centrifugal pump 54, while the other portion is collected through a branch pipe. A portion of the bottom fraction of the o-cresol column 51 is refluxed by the fifth reboiler 56, and the other portion is sent out by the tenth centrifugal pump 55. The first concentration monitor 92 monitors the phenol concentration in the raw material in real time. The system controller controls the opening of the first solenoid valve 95 based on the phenol concentration; the higher the phenol concentration, the larger the opening of the first solenoid valve 95. The tenth centrifugal pump... Pump 55 sends a portion of the raw material back to phenol tower 31 for further distillation, and another portion into cresol stripping tower 61. The raw material entering cresol stripping tower 61, after distillation, is condensed by the sixth condenser 62 to obtain a mixture of o-cresol and cresol. The mixture is then passed through the sixth reflux tank 63 and the eleventh centrifugal pump 64. Part of the mixture is sent back to cresol stripping tower 61 for reflux, part is collected, and part is sent to o-cresol tower 51 for further distillation. The bottom fraction of cresol stripping tower 61 is partly refluxed through the sixth reboiler 66 and the other part is sent to cresol tower 71 through the twelfth centrifugal pump 65. S4. The raw material entering the cresol tower 71, after rectification, is condensed by the seventh condenser 72 to obtain cresol. The cresol passes through the seventh reflux tank 73, and then through the thirteenth centrifugal pump 74. Part of the cresol is sent back to the top of the cresol tower 71 for reflux, and the other part is collected through a branch pipe. Part of the bottom fraction of the cresol tower 71 is refluxed by the seventh reboiler 76, and the other part is sent out by the fourteenth centrifugal pump 75. The second concentration monitor 94 monitors the concentration of o-cresol in the raw material sent out by the fourteenth centrifugal pump 75. The system controller controls the opening of the second solenoid valve 96 according to the o-cresol concentration. The higher the o-cresol concentration, the more open the second solenoid valve 96 becomes. The higher the concentration, the more the fourteenth centrifugal pump 75 sends a portion of the bottom fraction back to the o-cresol column 51 for further distillation, and the other portion to the recovery column 81. The raw material entering the recovery column 81, after being distilled in the recovery column 81, is condensed by the eighth condenser 82 to obtain a mixture of cresol, phenol, etc. The mixture passes through the eighth reflux tank 83, and through the fifteenth centrifugal pump 84, a portion of the mixture is sent to the top of the recovery column 81 for reflux, and the other portion is sent back to the cresol column 71 for further distillation through the third reflux pipe 88. A portion of the bottom fraction of the recovery column 81 is refluxed through the eighth reboiler 86, and the other portion is sent out for storage by the sixteenth centrifugal pump 85.

Claims

1. A multi-system circulating device for crude phenol separation, characterized in that, include: The dehydration unit (1) pre-treats the raw materials by dehydration; The deweighting unit (2) is connected to the dewatering unit (1) through a pipeline and performs deweighting treatment on the dewatered raw materials; The first distillation unit (3) is connected to the deweighting unit (2) through a pipeline and distills the phenol from the deweighted raw material. The second distillation unit (4) is connected to the first distillation unit (3) through a pipeline and removes residual phenol from the raw material discharged from the first distillation unit (3). The third distillation unit (5) is connected to the second distillation unit (4) via a pipeline and distills the o-cresol in the raw material discharged from the second distillation unit (4) to extract it. The fourth distillation unit (6) is connected to the third distillation unit (5) through a pipeline and removes residual o-cresol from the raw material discharged by the third distillation unit (5). The fifth distillation unit (7) is connected to the fourth distillation unit (6) via a pipeline and distills the cresol in the raw material discharged from the fourth distillation unit (6) to extract it. The recovery unit (8) is connected to the fifth distillation unit (7) via a pipeline and recovers low-boiling-point phenols from the raw materials discharged from the fifth distillation unit (7). The circulation unit (9) is located between the feed end of the fourth distillation unit (6) and the feed end of the first distillation unit (3), the feed end of the recovery unit (8) and the feed end of the third distillation unit (5). The circulation assembly is used to return high-concentration raw materials for re-distillation.

2. The multi-system circulating device for crude phenol separation according to claim 1, characterized in that, The dehydration unit (1) includes a dehydration tower (11), a first condenser (12), a first reflux tank (13), a first centrifugal pump (14), a second centrifugal pump (15), and a first reboiler (16). The feed end of the first condenser (12) is connected to the top of the dehydration tower (11) through a pipe, and the discharge end is connected to the top of the first reflux tank (13) through a pipe. The bottom end of the first reflux tank (13) is connected to the upper part of the dehydration tower (11) through the first centrifugal pump (14) and the first reflux pipe (17). A branch pipe for wastewater discharge is connected to the first reflux pipe (17). The bottom of the dehydration tower (11) is connected to the de-weighting unit (2) through the second centrifugal pump (15). The feed end of the first reboiler (16) is connected to the pipe between the dehydration tower (11) and the second centrifugal pump (15), and the discharge end is connected to the lower part of the dehydration tower (11). The deweight removal unit (2) includes a deweight removal tower (21), a second condenser (22), a second reflux tank (23), a third centrifugal pump (24), a fourth centrifugal pump (25), and a second reboiler (26). The bottom of the dehydration tower (11) is connected to the middle of the de-weighting tower (21) via the second centrifugal pump (15). The feed end of the second condenser (22) is connected to the top of the dehydration tower (11) via a pipe, and the discharge end is connected to the top of the second reflux tank (23) via a pipe. The bottom of the second reflux tank (23) is connected to the upper part of the de-weighting tower (21) via the third centrifugal pump (24) and the second reflux pipe (27). The bottom of the de-weighting tower (21) is connected to a pipe for waste discharge via the fourth centrifugal pump (25). The feed end of the second reboiler (26) is connected to the pipe between the de-weighting tower (21) and the fourth centrifugal pump (25), and the discharge end is connected to the lower part of the de-weighting tower (21). The second reflux pipe (27) is connected to the first distillation unit (3) via a branch pipe.

3. The multi-system circulating device for crude phenol separation according to claim 2, characterized in that, The first distillation unit (3) includes a phenol tower (31), a third condenser (32), a third reflux tank (33), a fifth centrifugal pump (34), a sixth centrifugal pump (35), and a third reboiler (36). The second reflux pipe (27) is connected to the middle of the phenol tower (31) through a branch pipe. The feed end of the third condenser (32) is connected to the top of the phenol tower (31) through a pipe, and the discharge end is connected to the top of the third reflux tank (33) through a pipe. The bottom of the third reflux tank (33) is connected to the upper part of the phenol tower (31) through the fifth centrifugal pump (34) and the third reflux pipe (37). A branch pipe for phenol product collection is connected to the third reflux pipe (37). The bottom of the phenol tower (31) is connected to the second distillation unit (4) through the sixth centrifugal pump (35). The feed end of the third reboiler (36) is connected to the pipe between the phenol tower (31) and the sixth centrifugal pump (35), and the discharge end is connected to the lower part of the phenol tower (31).

4. The multi-system circulating device for crude phenol separation according to claim 3, characterized in that, The second distillation unit (4) includes an o-cresol light removal column (41), a fourth condenser (42), a fourth reflux tank (43), a seventh centrifugal pump (44), an eighth centrifugal pump (45), and a fourth reboiler (46). The discharge end of the sixth centrifugal pump (35) is connected to the middle of the o-cresol light removal tower (41). The feed end of the fourth condenser (42) is connected to the top of the o-cresol light removal tower (41) via a pipe, and the discharge end is connected to the top of the fourth reflux tank (43) via a pipe. The bottom of the fourth reflux tank (43) is connected to the upper part of the o-cresol light removal tower (41) via the seventh centrifugal pump (44) and the fourth reflux pipe (47). A discharge pipe is also connected to the fourth reflux pipe (47). The branch pipe is used for the extraction of phenol and o-cresol mixture. The bottom of the o-cresol light removal tower (41) is connected to the third distillation unit (5) through the eighth centrifugal pump (45). The feed end of the fourth reboiler (46) is connected to the pipeline between the eighth centrifugal pump (45) and the o-cresol light removal tower (41), and the discharge end is connected to the lower part of the o-cresol light removal tower (41). The branch pipes of the fourth reflux pipe (47) and the second reflux pipe (27) are connected through the first reflux pipe (48).

5. The multi-system circulating device for crude phenol separation according to claim 4, characterized in that, The third distillation unit (5) includes an o-cresol tower (51), a fifth condenser (52), a fifth reflux tank (53), a ninth centrifugal pump (54), a tenth centrifugal pump (55), and a fifth reboiler (56). The discharge end of the eighth centrifugal pump (45) is connected to the middle of the o-cresol tower (51) through a pipe. The feed end of the fifth condenser (52) is connected to the top of the o-cresol tower (51) through a pipe, and the discharge end is connected to the top of the fifth reflux tank (53) through a pipe. The bottom of the fifth reflux tank (53) is connected to the upper part of the o-cresol tower (51) through the ninth centrifugal pump (54) and the fifth reflux pipe (57). A branch pipe for o-cresol product collection is also connected to the fifth reflux pipe (57). The bottom of the o-cresol tower (51) is connected to the fourth distillation unit (6) through the tenth centrifugal pump (55). The feed end of the fourth reboiler (46) is connected to the pipe between the tenth centrifugal pump (55) and the o-cresol tower (51), and the discharge end is connected to the lower part of the o-cresol tower (51).

6. The multi-system circulating device for crude phenol separation according to claim 5, characterized in that, The fourth distillation unit (6) includes a cresol light removal tower (61), a sixth condenser (62), a sixth reflux tank (63), an eleventh centrifugal pump (64), a twelfth centrifugal pump (65), and a sixth reboiler (66). The discharge end of the tenth centrifugal pump (55) is connected to the middle of the cresol light removal tower (61) via a pipe. The feed end of the sixth condenser (62) is connected to the top of the cresol light removal tower (61) via a pipe, and the discharge end is connected to the top of the sixth reflux tank (63) via a pipe. The bottom of the sixth reflux tank (63) is connected to the upper part of the cresol light removal tower (61) via the eleventh centrifugal pump (64) and the sixth reflux pipe (67). The sixth reflux pipe (67) is connected to a device for... The branch pipe and the second reflux pipe (68) from the o-cresol and cresol mixture are connected to the feed pipe of the o-cresol tower (51). The bottom of the cresol removal tower (61) is connected to the fifth distillation unit (7) through the twelfth centrifugal pump (65). The feed end of the sixth reboiler (66) is connected to the pipe between the twelfth centrifugal pump (65) and the cresol removal tower (61), and the discharge end is connected to the lower part of the cresol removal tower (61).

7. The multi-system circulating device for crude phenol separation according to claim 6, characterized in that, The fifth distillation unit (7) includes a cresol tower (71), a seventh condenser (72), a seventh reflux tank (73), a thirteenth centrifugal pump (74), a fourteenth centrifugal pump (75), and a seventh reboiler (76). The discharge end of the twelfth centrifugal pump (65) is connected to the middle of the cresol tower (71) through a pipe. The feed end of the seventh condenser (72) is connected to the top of the cresol tower (71) through a pipe, and the discharge end is connected to the top of the seventh reflux tank (73) through a pipe. The bottom of the seventh reflux tank (73) is connected to the upper part of the cresol tower (71) through the thirteenth centrifugal pump (74) and the seventh reflux pipe (77). The seventh reflux pipe (77) also has a branch pipe for cresol product collection. The bottom of the cresol tower (71) is connected to the recovery unit (8) through the fourteenth centrifugal pump (75). The feed end of the seventh reboiler (76) is connected to the pipe between the fourteenth centrifugal pump (75) and the cresol tower (71), and the discharge end is connected to the lower part of the cresol tower (71).

8. The multi-system circulating device for crude phenol separation according to claim 7, characterized in that, The recovery unit (8) includes a recovery tower (81), an eighth condenser (82), an eighth reflux tank (83), a fifteenth centrifugal pump (84), a sixteenth centrifugal pump (85), and an eighth reboiler (86). The discharge end of the fourteenth centrifugal pump (75) is connected to the middle of the recovery tower (81) through a pipe. The feed end of the eighth condenser (82) is connected to the top of the recovery tower (81) through a pipe, and the discharge end is connected to the top of the eighth reflux tank (83) through a pipe. The bottom of the eighth reflux tank (83) is connected to the upper part of the recovery tower (81) through the fifteenth centrifugal pump (84) and the eighth reflux pipe (87). The feed end of the eighth reflux pipe (87) and the cresol tower (71) is connected through the third reflux pipe (88). The bottom end of the recovery tower (81) is connected to the recovery pipe through the sixteenth centrifugal pump (85). The feed end of the eighth reboiler (86) is connected to the pipe between the sixteenth centrifugal pump (85) and the recovery tower (81), and the discharge end is connected to the lower part of the recovery tower (81).

9. The multi-system circulating device for crude phenol separation according to claim 8, characterized in that, The circulation unit (9) includes a first circulation pipe (91), a first concentration monitor (92), a second circulation pipe (93), a second concentration monitor (94), a first solenoid valve (95), and a second solenoid valve (96). The two ends of the first circulation pipe (91) are respectively connected to the pipe at the discharge end of the tenth centrifugal pump (55) and the branch pipe of the second return pipe (27). The first concentration monitor (92) is located on the pipe at the discharge end of the tenth centrifugal pump (55) and on the first circulation pipe (91). The first solenoid valve (95) is located on the first circulation pipe. On the ring pipe (91), the two ends of the second circulation pipe (93) are respectively connected to the pipe at the discharge end of the fourteenth centrifugal pump (75) and the pipe at the discharge end of the eighth centrifugal pump (45). The second concentration monitor (94) is located on the pipe at the discharge end of the fourteenth centrifugal pump (75) and the second circulation pipe (93). The second electric control valve (96) is located on the second circulation pipe (93). The first concentration monitor (92), the second concentration monitor (94), the first electric control valve (95) and the second electric control valve (96) are electrically connected to the controller of the entire system.

10. A separation method, comprising separating crude phenol using the multi-system circulation device for crude phenol separation as described in claim 9, characterized in that, Includes the following steps: S1. The crude phenol raw material first enters the dehydration tower (11) for dehydration pretreatment. The phenol-containing wastewater after distillation in the dehydration tower (11) is condensed by the first condenser (12) through the pipe at the top of the tower and flows into the first reflux tank (13). The first reflux tank (13) sends part of the phenol-containing wastewater back to the top of the dehydration tower (11) for reflux through the first centrifugal pump (14), and the other part is collected through the branch pipe. Part of the bottom fraction of the dehydration tower (11) is refluxed through the first reboiler (16), and the other part is collected through the second centrifugal pump (15). The raw material is fed into the middle of the de-heavy column (21). The de-heavy column (21) pre-treats the crude phenol raw material for de-heavy treatment. Part of the heavy fraction at the bottom of the column after distillation in the de-heavy column (21) is refluxed by the second reboiler (26), and the other part is sent out of the system for storage by the fourth centrifugal pump (25). The top fraction of the de-heavy column (21) flows into the second reflux tank (23) through the second condenser (22). Then, the light phenolic compounds are sent to the top of the column for reflux by the third centrifugal pump (24), and the other part is sent to the phenol column (31). S2. The raw material entering the phenol tower (31) is the phenol fraction at the top of the phenol tower (31) after distillation. It enters the third reflux tank (33) through the third condenser (32). Then, a portion of it is sent to the top of the tower for reflux and another portion is collected through the branch pipe by the fifth centrifugal pump (34). A portion of the bottom fraction of the phenol tower (31) is refluxed through the third reboiler (36) and another portion is sent to the o-cresol light removal tower (41) by the sixth centrifugal pump (35). The top fraction after distillation in the o-cresol light removal column (41) is condensed in the fourth condenser (42) to obtain a mixture of phenol and o-cresol. The mixture enters the fourth reflux tank (43) and is then divided into three parts by the seventh centrifugal pump (44). One part is sent to the top of the o-cresol light removal column (41) for reflux, another part is collected, and the third part is sent to the phenol column (31) for further distillation. The bottom fraction of the o-cresol light removal column (41) is refluxed in the fourth reboiler (46) and sent to the o-cresol column (51) by the eighth centrifugal pump (45). S3. The raw material entering the o-cresol tower (51) is condensed by the fifth condenser (52) after the distillation of the o-cresol tower (51) to obtain o-cresol. After passing through the fifth reflux tank (53), a portion of the reflux is sent to the top of the o-cresol tower (51) for reflux by the ninth centrifugal pump (54), and the other portion is collected through the branch pipe. A portion of the bottom fraction of the o-cresol tower (51) is refluxed by the fifth reboiler (56), and the other portion is sent out by the tenth centrifugal pump (55). The first concentration monitor (92) monitors the phenol concentration in the raw material in real time. The system controller controls the opening of the first electric control valve (95) according to the phenol concentration. The higher the phenol concentration, the larger the opening of the first electric control valve (95). The tenth centrifugal pump (95) 55) A portion of the raw material is sent back to the phenol tower (31) for further distillation, and another portion is sent to the cresol light removal tower (61). The raw material entering the cresol light removal tower (61) is condensed by the sixth condenser (62) to obtain a mixture of o-cresol and cresol. The mixture is sent through the sixth reflux tank (63) and the eleventh centrifugal pump (64) to reflux a portion of the mixture into the cresol light removal tower (61), collect a portion, and send a portion into the o-cresol tower (51) for further distillation. A portion of the bottom fraction of the cresol light removal tower (61) is refluxed through the sixth reboiler (66), and another portion is sent into the cresol tower (71) through the twelfth centrifugal pump (65). S4. The raw material entering the cresol tower (71) is condensed by the seventh condenser (72) after the top fraction of the cresol tower (71) is condensed to obtain cresol. The cresol is then sent through the seventh reflux tank (73), and then by the thirteenth centrifugal pump (74) a portion of the cresol is sent to the top of the cresol tower (71) for reflux, and the other portion is collected through the branch pipe. A portion of the bottom fraction of the cresol tower (71) is refluxed by the seventh reboiler (76), and the other portion is sent out by the fourteenth centrifugal pump (75). The second concentration monitor (94) monitors the o-cresol concentration in the raw material sent out by the fourteenth centrifugal pump (75). The system controller controls the opening of the second electric control valve (96) according to the o-cresol concentration. The higher the o-cresol concentration, the higher the opening of the second electric control valve (96). The larger the volume, the fourteenth centrifugal pump (75) sends a portion of the bottom fraction back to the o-cresol column (51) for further distillation, and the other portion is sent to the recovery column (81). The raw material entering the recovery column (81) and the top fraction after distillation in the recovery column (81) are condensed by the eighth condenser (82) to obtain a mixture of cresol, phenol and other substances. The mixture passes through the eighth reflux tank (83), and a portion of the mixture is sent to the top of the recovery column (81) for reflux by the fifteenth centrifugal pump (84), and the other portion is sent back to the cresol column (71) for further distillation through the third reflux pipe (88). A portion of the bottom fraction of the recovery column (81) is refluxed by the eighth reboiler (86), and the other portion is sent out for storage by the sixteenth centrifugal pump (85).

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