Coking meta- and para-cresol purification plant

Abstract

A kind of purification device of coking meta-methyl phenol and p-methyl phenol, mixed phenol tank is connected with the feed port of simulated moving bed by raw material phenol pump, the crude meta-cresol liquid discharge port of simulated moving bed is connected with the inlet of meta-cresol rectifying tower, the resolving agent steam discharge port of meta-cresol rectifying tower is connected with resolving agent circulating unit, the meta-cresol discharge port of meta-cresol rectifying tower is connected with crystallization unit by crystallization raw material pump, the mixed phenol output port of crystallization unit is connected with mixed phenol tank, the output pipe of miscellaneous phenol outputs miscellaneous phenol, the meta-cresol product output port is connected with meta-cresol product tank;The crude p-cresol liquid discharge port of simulated moving bed is connected with p-cresol rectifying tower, the resolving agent steam discharge port of p-cresol rectifying tower is connected with resolving agent circulating unit, the p-cresol discharge port of p-cresol rectifying tower is connected with p-cresol product tank, the resolving agent output port of resolving agent circulating unit is connected with the resolving agent inlet of simulated moving bed.The utility model has the advantages of small environmental pollution, product purity is high.

Description

Technical Field

[0001] This utility model belongs to the field of purification equipment technology, specifically relating to a purification device for coking m-methylphenol and p-methylphenol. Background Technology

[0002] Pure m-p-phenol has wide industrial applications, including as a raw material for synthesizing other chemicals such as antioxidants, fragrances, dyes, pharmaceuticals, and pesticides, and has high economic value. However, mixed m-p-phenol products cannot fully utilize their individual properties, resulting in their limited use only in the production of enameled wire, leading to significant waste. The refining of coal tar byproducts in the coal chemical industry generates large quantities of m-p-phenol mixtures containing various impurities. Developing separation technologies for these mixtures has significant economic and social implications.

[0003] m-cresol and p-cresol have similar molecular structures and similar boiling points at normal pressure (difference of 0.5°C), making them difficult to separate using conventional processes such as distillation. Currently, the widely used industrial separation technology is alkylation separation, which involves introducing alkyl groups onto cresols through a chemical reaction, changing the relative difference in boiling points between the two substances, separating them by distillation, and then removing the alkyl groups through a chemical reaction after separation. This process can achieve high-purity separation of m- and p-cresols, but due to the need for a chemical reaction and limitations imposed by the process, it suffers from disadvantages such as low utilization of alkylation reagents, environmental pollution, and high production costs.

[0004] For example, Chinese patent CN95107472.5, entitled "Separation and Purification Process of p-cresol by Complexation Extraction Crystallization Method", involves a separation process using complexation crystallization that can only extract p-cresol as a high-purity product, but cannot obtain high-purity m-cresol. Furthermore, the process requires the introduction of chemical agents such as piperazine and oxalic acid, which has an adverse impact on the environment and production costs.

[0005] For example, Chinese patent CN202020558406.2, "Reaction Crystallizer for Separation and Purification of m- and p-cresol", involves the crystallization and separation of m- and p-cresol, which is subject to the influence of the purity of the crystallization raw material. This patent is a crystallizer device, and according to the phase diagram of m- and p-cresol mixtures, the device must require that the raw material contains at least 90% m- or p-cresol, otherwise crystallization cannot be carried out.

[0006] Chinese Patent 202211622247.8, "A Method for Separating and Purifying m-p-cresol," uses a chromatographic column as its adsorption separation device. Its operation is intermittent, requiring a wash after each adsorption cycle to separate the adsorbed p-cresol from the unadsorbed m-cresol. This makes continuous operation impractical for industrial production. Due to the intermittent operation, the adsorption capacity of the adsorbent cannot be fully utilized, resulting in relatively high solvent consumption per unit of raw material and high energy consumption in subsequent distillation separation. This patent lacks an outlet for discharging impurities from the m-p-cresol feed to the m- and p-cresol discharges. Some impurities are discharged along with the m- and p-cresol products, directly limiting the purity of the products. Other impurities circulate and gradually accumulate within the system with the eluent, making continuous operation impossible. This patent involves two distillation separation processes: the p-cresol extract and the m-cresol residue are separately distilled to obtain crude products, and then further distilled to obtain refined products. This multiple distillation process increases the complexity of the process, which may lead to increased equipment investment, greater operational difficulty, and higher energy consumption. Utility Model Content

[0007] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a coking m-methylphenol and p-methylphenol purification device with no chemical reagent consumption, low environmental pollution, and high product purity.

[0008] The technical solution adopted to solve the above-mentioned technical problems is as follows: a coking m-cresol and p-cresol purification device, wherein a mixed phenol tank is connected to the feed inlet of a simulated moving bed via a raw material phenol pump; the crude m-cresol liquid outlet of the simulated moving bed is connected to the inlet of a m-cresol distillation column via a pipeline; the eluent liquid at the top of the m-cresol distillation column (this eluent will condense into liquid eluent under the action of the top condenser and then enter the next device) is connected to the first eluent inlet of the eluent circulation unit via a pipeline; the m-cresol outlet at the bottom of the m-cresol distillation column is connected to the m-cresol inlet of the crystallization unit via a crystallization raw material pump; and the crystallization unit... The system separates mixed phenols, m-cresol products, and creosotes. The mixed phenol outlet of the crystallization unit is connected to the mixed phenol tank via a pipeline, the creosote outlet pipe outputs creosote, and the m-cresol product outlet is connected to the m-cresol product tank via a pipeline. The crude p-cresol liquid outlet of the simulated moving bed is connected to the inlet of the p-cresol distillation column via a pipeline. The eluent vapor outlet at the top of the p-cresol distillation column is connected to the second eluent inlet of the eluent circulation unit via a pipeline. The p-cresol outlet at the bottom of the p-cresol distillation column is connected to the p-cresol product tank via a pipeline. The eluent outlet of the eluent circulation unit is connected to the eluent inlet of the simulated moving bed via a pipeline.

[0009] Preferably, the crystallization unit includes a crystallization raw material tank, a crystallization separator, a mother liquor purification tower, and a first condenser. The m-cresol inlet of the crystallization raw material tank is connected to the outlet of the crystallization raw material pump via a pipeline. The outlet of the crystallization raw material tank is connected to the inlet of the crystallization separator. The m-cresol mother liquor outlet of the crystallization separator is connected to the inlet of the mother liquor purification tower via a pipeline. The m-cresol product outlet at the bottom of the crystallization separator is connected to the m-cresol product tank via a pipeline. The mixed phenol vapor outlet of the mother liquor purification tower is connected to the m-cresol vapor inlet of the first condenser via a pipeline. The mixed phenol outlet of the first condenser is connected to the mixed phenol tank via a pipeline. A phenolic output pipe is provided at the bottom of the mother liquor purification tower.

[0010] Preferably, the refrigerant circulation unit includes a second condenser, a third condenser, a refrigerant buffer tank, and a refrigerant pump. The refrigerant vapor inlet of the second condenser is connected to the refrigerant vapor outlet at the top of the p-cresol distillation column via a pipeline, and the refrigerant outlet is connected to the second refrigerant inlet of the refrigerant buffer tank via a pipeline. The refrigerant vapor inlet of the third condenser is connected to the refrigerant vapor outlet at the top of the m-cresol distillation column via a pipeline, and the refrigerant outlet is connected to the first refrigerant inlet of the refrigerant buffer tank via a pipeline. The refrigerant outlet of the refrigerant buffer tank is connected to the refrigerant inlet of the simulated moving bed via the refrigerant pump.

[0011] Preferably, the bottom of the simulated moving bed is provided with a residual liquid outlet, which is connected to the residual liquid circulation inlet at the top of the simulated moving bed through a residual liquid pump.

[0012] The beneficial effects of this utility model are as follows: This invention employs conventional adsorption towers, crystallizers, and distillation towers to achieve adsorption, crystallization, and distillation processes. All three processes are physical processes and do not involve chemical reactions. Compared with traditional alkylation separation processes, this not only reduces the consumption of chemical reagents and lowers production costs, but also reduces waste liquid discharge, making it more environmentally friendly.

[0013] This invention, by simulating the synergistic effect of efficient adsorption separation and distillation / crystallization processes in a moving bed, can improve the yield of m-cresol and p-cresol while ensuring high product purity.

[0014] This invention can simultaneously produce m-cresol and p-cresol, overcoming the limitation of traditional methods that can only obtain a single high-purity product. Moreover, the reagent recycling unit of this invention enables the recovery and reuse of the reagent, significantly improving resource utilization and economic benefits. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0017] exist Figure 1 In this embodiment, a coking m-cresol and p-cresol purification device includes a mixing phenol tank 1, a raw material phenol pump 2, a simulated moving bed 3, a discharge liquid pump 4, a m-cresol distillation column 5, a third condenser 6, a crystallization raw material pump 7, an eluent pump 8, a crystallization raw material tank 9, a m-cresol product tank 10, a crystallization separator 11, a p-cresol product tank 12, a phenol output pipe 13, a mother liquor purification column 14, a second condenser 15, a first condenser 16, a p-cresol distillation column 17, and an eluent buffer tank 18.

[0018] The mixed phenol tank 1 contains mixed phenolic raw materials, which include m-cresol, p-cresol, as well as other impurities such as phenol, xylenol, and neutral oil. The mixed phenol tank 1 is connected to the feed inlet of the simulated moving bed 3 through the raw material phenol pump 2. The raw material phenol pump 2 transports the mixed phenolic raw materials in the mixed phenol tank 1 to the simulated moving bed 3.

[0019] The method for separating m-cresol and p-cresol using the simulated moving bed 3 in this embodiment has been disclosed in Chinese Patent 201910182997.X, "A Method for Adsorption Separation of p-cresol and m-cresol".

[0020] The crude m-cresol liquid outlet of the simulated moving bed 3 is connected to the inlet of the m-cresol distillation column 5 via a pipeline. The eluent vapor outlet at the top of the m-cresol distillation column 5 is connected to the eluent circulation unit via a pipeline. The m-cresol outlet at the bottom of the m-cresol distillation column 5 is connected to the m-cresol inlet of the crystallization feed tank 9 via the crystallization feed pump 7. The outlet of the crystallization feed tank 9 is connected to the inlet of the crystallization separator 11. The crystallization separator 11 separates the m-cresol mother liquor and the m-cresol product. The m-cresol product outlet at the bottom of the crystallization separator 11 is connected to the m-cresol product tank 10 via a pipeline for outputting the m-cresol product to the m-cresol product tank 10. The m-cresol mother liquor outlet of separator 11 is connected to the inlet of mother liquor purification tower 14 via a pipeline, which is used to output the separated m-cresol mother liquor to mother liquor purification tower 14. The pure m-cresol vapor outlet of mother liquor purification tower 14 is connected to the m-cresol vapor inlet of first condenser 16 via a pipeline. The mixed phenol outlet of first condenser 16 is connected to mixed phenol tank 1 via a pipeline. A phenol output pipe 13 is installed at the bottom of mother liquor purification tower 14. Mother liquor purification tower 14 is used to separate m-cresol from impurities. The extracted pure m-cresol vapor enters first condenser 16, is condensed into mixed phenol liquid and enters mixed phenol tank 1 for the next round of m-cresol product generation.

[0021] The crude p-cresol liquid outlet of the simulated moving bed 3 is connected to the inlet of the p-cresol distillation column 17 via a pipeline. The p-cresol distillation column 17 further purifies the crude p-cresol liquid separated from the simulated moving bed 3. The p-cresol outlet at the bottom of the p-cresol distillation column 17 is connected to the p-cresol product tank 12 via a pipeline. The p-cresol product purified by the p-cresol distillation column 17 is output to the p-cresol product tank 12 through the p-cresol outlet at the bottom. The eluent vapor outlet at the top of the p-cresol distillation column 17 is connected to the eluent circulation unit via a pipeline.

[0022] The eluent circulation unit of this embodiment includes a second condenser 15, a third condenser 6, an eluent buffer tank 18, and an eluent pump 8. The eluent vapor inlet of the second condenser 15 is connected to the eluent vapor outlet at the top of the p-cresol distillation column 17 via a pipe, and the eluent outlet is connected to the second eluent inlet of the eluent buffer tank 18 via a pipe. The eluent vapor inlet of the third condenser 6 is connected to the eluent vapor outlet at the top of the m-cresol distillation column 5 via a pipe, and the eluent outlet is connected to the first eluent inlet of the eluent buffer tank 18 via a pipe. The eluent outlet of the eluent buffer tank 18 is connected to the eluent inlet of the simulated moving bed 3 via the eluent pump 8.

[0023] In this embodiment, the simulated moving bed 3 is provided with a residual liquid outlet at the bottom, which is connected to the residual liquid circulation inlet at the top of the simulated moving bed 3 via a residual liquid pump 4. Since the residual liquid at the bottom may contain some incompletely separated m-cresol, p-cresol, and other components, by pumping the residual liquid back to the top of the simulated moving bed 3, these components can participate in the adsorption and separation process again, improving the utilization rate of raw materials and reducing resource waste.

[0024] The working principle of this utility model is as follows: The raw material phenol pump 2 transports the raw material from the mixed phenol tank 1 to the simulated moving bed 3 for adsorption separation. In the simulated moving bed 3, m-cresol and p-cresol are adsorbed and separated, yielding crude m-cresol solution and crude p-cresol solution, respectively. These solutions then enter the m-cresol distillation column 5 and the p-cresol distillation column 17 for further distillation to improve purity. The m-cresol at the bottom of the m-cresol distillation column 5 enters the crystallization raw material tank 9, and then the crystallization separator 11. Through crystallization and separation, m-cresol product and m-cresol mother liquor are obtained. The m-cresol mother liquor is purified and returned to the mixed phenol tank 1 for further processing. The eluent vapors at the top of the m-cresol distillation column 5 and the p-cresol distillation column are condensed by the second condenser 15 and the third condenser 6, respectively, and then flow into the eluent buffer tank 18, before being recycled back to the simulated moving bed 3, achieving efficient recovery and utilization of the eluent.

Claims

1. A purification apparatus for coking m-methylphenol and p-methylphenol, characterized in that: The mixed phenol tank (1) is connected to the feed inlet of the simulated moving bed (3) via the raw material phenol pump (2). The crude m-cresol liquid outlet of the simulated moving bed (3) is connected to the inlet of the m-cresol distillation column (5) via a pipeline. The eluent vapor outlet at the top of the m-cresol distillation column (5) is connected to the first inlet of the eluent circulation unit via a pipeline. The m-cresol outlet at the bottom of the m-cresol distillation column (5) is connected to the m-cresol inlet of the crystallization unit via the crystallization raw material pump (7). The crystallization unit separates mixed phenol, m-cresol product, and miscellaneous phenols. The mixed phenol outlet of the crystallization unit is connected to the mixed phenol tank (1) via a pipeline. The creosote output pipe (13) outputs creosote and the m-cresol product output port is connected to the m-cresol product tank (10) through a pipe; the crude p-cresol liquid outlet of the simulated moving bed (3) is connected to the inlet of the p-cresol distillation column (17) through a pipe; the eluent liquid outlet at the top of the p-cresol distillation column (17) is connected to the second eluent inlet of the eluent circulation unit through a pipe; the p-cresol outlet at the bottom of the p-cresol distillation column (17) is connected to the p-cresol product tank (12) through a pipe; and the eluent output port of the eluent circulation unit is connected to the eluent inlet of the simulated moving bed (3) through a pipe.

2. The coking m-methylphenol and p-methylphenol purification apparatus according to claim 1, characterized in that: The crystallization unit includes a crystallization raw material tank (9), a crystallization separator (11), a mother liquor purification tower (14), and a first condenser (16). The m-cresol inlet of the crystallization raw material tank (9) is connected to the outlet of the crystallization raw material pump (7) through a pipeline. The outlet of the crystallization raw material tank (9) is connected to the inlet of the crystallization separator (11). The m-cresol mother liquor outlet of the crystallization separator (11) is connected to the inlet of the mother liquor purification tower (14) through a pipeline. The m-cresol product outlet at the bottom of the crystallization separator (11) is connected to the m-cresol product tank (10) through a pipeline. The mixed phenol vapor outlet of the mother liquor purification tower (14) is connected to the m-cresol vapor inlet of the first condenser (16) through a pipeline. The mixed phenol outlet of the first condenser (16) is connected to the mixed phenol tank (1) through a pipeline. A phenol output pipe (13) is provided at the bottom of the mother liquor purification tower (14).

3. The coking m-methylphenol and p-methylphenol purification apparatus according to claim 1, characterized in that: The resolving agent circulation unit includes a second condenser (15), a third condenser (6), a resolving agent buffer tank (18), and a resolving agent pump (8). The resolving agent vapor inlet of the second condenser (15) is connected to the resolving agent vapor outlet at the top of the p-cresol distillation column (17) via a pipe, and the resolving agent outlet is connected to the second resolving agent inlet of the resolving agent buffer tank (18) via a pipe. The resolving agent vapor inlet of the third condenser (6) is connected to the resolving agent vapor outlet at the top of the m-cresol distillation column (5) via a pipe, and the resolving agent outlet is connected to the first resolving agent inlet of the resolving agent buffer tank (18) via a pipe. The resolving agent outlet of the resolving agent buffer tank (18) is connected to the resolving agent inlet of the simulated moving bed (3) via the resolving agent pump (8).

4. The coking m-methylphenol and p-methylphenol purification apparatus according to claim 1, characterized in that: The bottom of the simulated moving bed (3) is provided with a residual liquid outlet, which is connected to the residual liquid circulation inlet at the top of the simulated moving bed (3) through a residual liquid pump (4).

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