System and method for separating pentaerythritol and calcium formate from pentaerythritol mother liquor

Abstract

A system for separating pentaerythritol and calcium formate from pentaerythritol mother liquor, comprising an extraction column, a back-extraction column, a dilute solvent recovery column, a solvent recovery column, a solvent recovery reboiler, a dilute solvent recovery reboiler, a solvent recovery condenser, a solvent recovery tail cooler, a solvent recovery reboiler, a mother liquor feed pump, an extractant feed pump, a dilute solvent recovery feed pump, a solvent recovery circulation pump, a solvent recovery discharge pump, a solvent recovery reflux pump, a solvent recovery vacuum pump, a mother liquor tank, an extractant tank, a raffinate tank, an extract liquid tank, a dilute solvent recovery separator, and a solvent recovery column reflux tank; this system can achieve cyclic continuous treatment of pentaerythritol mother liquor. The pentaerythritol and calcium formate products separated by this system have high quality and high recovery rate. The extractant can be separated, recovered, and recycled, greatly reducing the treatment cost of separating pentaerythritol and calcium formate from pentaerythritol mother liquor, and significantly reducing the discharged waste liquid, thus reducing the pressure of environmental protection treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of biochemical equipment manufacturing, and particularly relates to a system and method for separating pentaerythritol and calcium formate from pentaerythritol mother liquor. Background Art

[0002] Pentaerythritol, belonging to polyhydric alcohols organic compounds, is white crystalline or powdery, flammable, and is a key raw material for producing high-solid content, water-soluble and general alkyd resins, rosin esters, synthetic lubricants and antioxidants. During the production of pentaerythritol, a large amount of mother liquor is produced. The mother liquor contains a considerable amount of pentaerythritol and calcium formate with industrial value. If the mother liquor is not recycled, not only a large amount of pentaerythritol and calcium formate industrial products will be lost, but also serious environmental problems will be caused. In the existing mother liquor recycling process, due to the concentration process making the mother liquor enriched and viscous, it is difficult to separate pentaerythritol crystals from the mother liquor. A large amount of pentaerythritol is not effectively recovered, the recovery rates of pentaerythritol and calcium formate are relatively low, the product quality is average, the consumption of organic solvents is large, the separation cost is high, and the content of organic substances in the waste liquid after treatment is high, and there are still serious environmental problems.

[0003] Therefore, a system and method for separating pentaerythritol and calcium formate from pentaerythritol mother liquor are designed to solve the above problems.

[0004] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of the present invention and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of the present invention. Summary of the Invention

[0005] To overcome the deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a system and method for separating pentaerythritol and calcium formate from pentaerythritol mother liquor.

[0006] To achieve the above and other related objectives, the technical solution provided by the present invention is: A system for separating pentaerythritol and calcium formate from pentaerythritol mother liquor, comprising an extraction tower, a back-extraction tower, a dilute solvent recovery tower, a solvent recovery tower, a demineralized water heater, a solvent recovery reboiler I, a dilute solvent recovery reboiler, a solvent recovery condenser, a solvent recovery tail cooler, a solvent recovery reboiler II, a mother liquor feed pump, an extractant feed pump, a dilute solvent recovery feed pump, a solvent recovery feed pump, a dilute solvent recovery bottom pump, a solvent recovery circulation pump, a solvent recovery discharge pump, a solvent recovery reflux pump, a solvent recovery vacuum pump, a mother liquor tank, an extractant tank, a raffinate tank, an extract tank, a dilute solvent recovery separator, and a solvent recovery tower reflux tank; The upper inlet of the extraction tower is connected to the mother liquor tank through a pipeline and a mother liquor feed pump, the lower inlet opened on the extraction tower is connected to the extractant tank through a pipeline and an extractant feed pump, the upper outlet of the extraction tower is connected to the lower inlet of the back-extraction tower through a pipeline, and the lower outlet of the extraction tower is connected to the inlet opened on the raffinate tank through a pipeline; The upper inlet of the back-extraction tower is connected to the outlet of the demineralized water heater through a pipeline, the upper outlet of the back-extraction tower is connected to the upper inlet of the extract tank through a pipeline, and the lower outlet of the back-extraction tower is connected to the upper inlet of the raffinate tank through a pipeline; The upper inlet of the dilute solvent recovery tower is connected to the outlet of the dilute solvent recovery feed pump through a pipeline, the upper outlet of the dilute solvent recovery tower is connected to the upper inlet of the solvent recovery reboiler I through a pipeline, the lower outlet of the dilute solvent recovery tower is respectively connected to the lower inlet of the dilute solvent recovery reboiler and the inlet of the dilute solvent recovery bottom pump through pipelines, and the upper outlet of the dilute solvent recovery reboiler is connected to the lower inlet of the dilute solvent recovery tower through a pipeline; The middle inlet of the solvent recovery tower is connected to the outlet of the solvent recovery feed pump through a pipeline, the upper inlet of the solvent recovery tower is connected to the outlet of the solvent recovery reflux pump through a pipeline, the lower inlet of the solvent recovery tower is connected to the outlet of the solvent recovery reboiler II through a pipeline, the upper outlet of the solvent recovery tower is connected to the upper inlet of the solvent recovery condenser through a pipeline, and the lower outlet of the solvent recovery tower is connected to the inlet of the solvent recovery circulation pump through a pipeline; The material inlet of the mother liquor heater is connected to the outlet of the mother liquor feed pump through a pipeline, the heating side inlet of the mother liquor heater is connected to the steam inlet pipeline, and the heating side outlet of the mother liquor heater is connected to the condensate recovery pipeline; The feed inlet of the extractant heater is connected to the outlet of the extractant feed pump through a pipeline, the heating side inlet of the extractant heater is connected to the steam inlet pipeline, and the heating side outlet of the extractant heater is connected to the condensate recovery pipeline; The feed inlet of the demineralized water heater is connected to the demineralized water pipeline, the heating side inlet of the demineralized water heater is connected to the steam inlet pipeline, and the heating side outlet of the demineralized water heater is connected to the condensate recovery pipeline; The discharge outlet of the solvent recovery reboiler I is connected to the top feed inlet of the dilute solvent recovery separator through a pipeline, the cooling side inlet of the solvent recovery reboiler I is connected to the circulating water inlet pipeline, and the cooling side outlet of the solvent recovery reboiler I is connected to the circulating water return pipeline;The inlet of the heating side of the dilute solvent recovery reboiler is connected to the steam inlet pipe, and the outlet of the heating side of the dilute solvent recovery reboiler is connected to the condensate recovery pipe; the discharge port of the solvent recovery condenser is connected to the upper feed port of the solvent recovery tower reflux tank through a pipe, the inlet of the cooling side of the solvent recovery condenser is connected to the circulating water inlet pipe, and the outlet of the cooling side of the solvent recovery condenser is connected to the circulating water return pipe; the inlet of the solvent recovery tail cooler is connected to the upper outlet of the solvent recovery tower reflux tank through a pipe, the outlet of the solvent recovery tail cooler is connected to the solvent recovery vacuum pump through a pipe, the inlet of the cooling side of the solvent recovery tail cooler is connected to the circulating water inlet pipe, and the outlet of the cooling side of the solvent recovery tail cooler is connected to the circulating water return pipe; the upper feed port above the second solvent recovery reboiler is connected to the outlet of the solvent recovery circulation pump through a pipe, the bottom outlet of the second solvent recovery reboiler is connected to the inlet of the solvent recovery discharge pump through a pipe, the inlet of the heating side of the second solvent recovery reboiler is connected to the steam inlet pipe, and the outlet of the heating side of the second solvent recovery reboiler is connected to the condensate recovery pipe; the inlet of the mother liquor feed pump is connected to the outlet of the mother liquor tank through a pipe; the inlet of the extractant feed pump is connected to the bottom outlet of the extractant tank through a pipe; the inlet of the dilute solvent recovery feed pump is connected to the bottom outlet of the raffinate tank through a pipe; the inlet of the solvent recovery feed pump is connected to the bottom outlet of the extract solution tank through a pipe; the outlet of the dilute solvent recovery tower bottom pump is connected to the pipe for wastewater treatment; the outlet of the solvent recovery discharge pump is connected to the pipe for the collection tank; the inlet of the solvent recovery reflux pump is connected to the bottom outlet of the solvent recovery tower reflux tank through a pipe, and the outlet of the solvent recovery reflux pump is connected to the upper inlet of the extractant tank through a pipe; the upper inlet of the mother liquor tank is connected to the mother liquor pipe; the upper inlet of the extractant tank is connected to the isooctanol pipe; the lower outlet of the extract solution tank is connected to the upper inlet of the raffinate tank through a pipe; the upper outlet of the dilute solvent recovery separator is connected to the upper inlet of the extractant tank through a pipe, and the bottom outlet of the dilute solvent recovery separator is connected to the upper inlet of the dilute solvent recovery separator through a pipe to form a circulation loop, and an outlet is provided at the middle position of the circulation loop and is connected to the upper inlet of the raffinate tank through a pipe.;

[0007] Preferably, a mother liquor heater is provided between the extraction tower and the mother liquor feed pump.

[0008] Preferably, an extractant heater is provided between the extraction tower and the extractant feed pump.

[0009] Preferably, valves are provided on all pipes.

[0010] A method for separating pentaerythritol and calcium formate from pentaerythritol mother liquor, which comprises the following steps:

[0011] Step 1: The pentaerythritol mother liquor is input into the mother liquor tank through a pipeline for storage, and then enters the upper part of the extraction tower through the mother liquor feed pump. The liquid in the extractant storage tank is pressurized by the extractant feed pump and enters the lower part of the extraction tower. The liquid at the bottom of the extraction tower enters the raffinate tank, and the liquid at the top of the extraction tower enters the bottom of the stripping tower.

[0012] Step 2: Demineralized water enters the upper part of the stripping tower through the demineralized water feed device. The liquid at the top of the stripping tower enters the extract tank, and the liquid at the bottom of the stripping tower enters the raffinate tank.

[0013] Step 3: The liquid in the raffinate tank is pressurized by the dilute solvent recovery feed pump and sent to the upper part of the dilute solvent recovery tower. The steam at the top of the dilute solvent recovery tower enters the dilute solvent recovery condenser, and the condensate enters the dilute solvent recovery separator. The oil layer returns to the extractant tank for recycling, and the water layer returns to the extract tank to continue recovering the solvent therein. The dilute solvent recovery reboiler at the lower part of the dilute solvent recovery tower uses steam as the heat source for heating. The wastewater with less solvent at the bottom of the tower is pressurized by the solvent recovery tower bottom pump and sent out.

[0014] Step 4: The extraction tank is provided with a low-level water separation. The separated water layer goes to the raffinate tank. The oil layer in the extraction tank is pressurized by the solvent recovery feed pump and sent to the middle part of the solvent recovery tower. The steam at the top of the solvent recovery tower enters the solvent recovery condenser and the solvent recovery tail cooler. The condensate enters the solvent recovery tower reflux tank, and after being pressurized by the solvent recovery reflux pump, part of it flows back into the solvent recovery tower, and part of it is sent to the extractant tank for recycling. The liquid at the bottom of the solvent recovery tower is pressurized by the solvent recovery circulation pump and sent to the second solvent recovery reboiler. The second solvent recovery reboiler uses steam as the heat source for heating. The heated gas-liquid phase enters the bottom of the solvent recovery tower. The high-boiling substances are taken out from the lower head of the second solvent recovery reboiler and sent out by the solvent recovery discharge pump. The solvent recovery tower operates under vacuum, and the solvent recovery vacuum pump is used to evacuate it.

[0015] Due to the application of the above technical solution, the advantages of the present invention compared with the prior art are as follows:

[0016] The system and method for separating pentaerythritol and calcium formate from the pentaerythritol mother liquor designed in this solution can realize the cyclic continuous treatment of the pentaerythritol mother liquor. The pentaerythritol and calcium formate products separated by this system have high quality and high recovery rate. The extractant can be separated, recovered and recycled, greatly reducing the treatment cost of separating pentaerythritol and calcium formate from the pentaerythritol mother liquor, and greatly reducing the discharged waste liquid, reducing the pressure of environmental protection treatment. This system has a compact structure, simple operation, small floor area and small investment. It not only improves the treatment efficiency of the pentaerythritol mother liquor, improves the recovery rate of pentaerythritol and calcium formate, but also reduces the consumption of organic solvents, saves energy, and has good application prospects and comprehensive economic benefits. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the overall system structure.

[0018] In the above drawings, extraction tower 1, stripping tower 2, dilute solvent recovery tower 3, solvent recovery tower 4, mother liquor heater 5, extractant heater 6, demineralized water heater 7, solvent recovery reboiler I 8, dilute solvent recovery reboiler 9, solvent recovery condenser 10, solvent recovery tail cooler 11, solvent recovery reboiler II 12, mother liquor feed pump 13, extractant feed pump 14, dilute solvent recovery feed pump 15, solvent recovery feed pump 16, dilute solvent recovery bottom pump 17, solvent recovery circulation pump 18, solvent recovery discharge pump 19, solvent recovery reflux pump 20, solvent recovery vacuum pump 21, mother liquor tank 22, extractant tank 23, raffinate tank 24, extract liquid tank 25, dilute solvent recovery decanter 26, solvent recovery tower reflux tank 27. Detailed implementation manners

[0019] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0020] Please refer to Figure 1 . It should be noted that in the description of the present invention, it needs to be explained that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance. The terms "horizontal", "vertical", "hanging", etc. do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0021] In the description of the present invention, it also needs to be explained that unless otherwise clearly defined and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0022] Example: A system for separating pentaerythritol and calcium formate from pentaerythritol mother liquor, comprising an extraction column (1), a back-extraction column (2), a dilute solvent recovery column (3), a solvent recovery column (4), a mother liquor heater (5), an extractant heater (6), a desalted water heater (7), a solvent recovery reboiler I (8), a dilute solvent recovery reboiler (9), a solvent recovery condenser (10), a solvent recovery tail cooler (11), a solvent recovery reboiler II (12), a mother liquor feed pump (13), an extractant feed pump (14), a dilute solvent recovery feed pump (15), a solvent recovery feed pump (16), a dilute solvent recovery bottom pump (17), a solvent recovery circulation pump (18), a solvent recovery discharge pump (19), a solvent recovery reflux pump (20), a solvent recovery vacuum pump (21), a mother liquor tank (22), an extractant tank (23), a raffinate tank (24), an extract liquid tank (25), a dilute solvent recovery decanter (26), and a solvent recovery column reflux tank (27); the upper inlet of the extraction column (1) is connected to the outlet of the mother liquor heater (5) through a pipeline, the lower inlet of the extraction column (1) is connected to the outlet of the extractant heater (6) through a pipeline, the upper outlet of the extraction column (1) is connected to the lower inlet of the back-extraction column (2) through a pipeline, and the lower outlet of the extraction column (1) is connected to the upper inlet of the raffinate tank (24) through a pipeline; the upper inlet of the back-extraction column (2) is connected to the outlet of the desalted water heater (7) through a pipeline, the upper outlet of the back-extraction column (2) is connected to the upper inlet of the extract liquid tank (25) through a pipeline, and the lower outlet of the back-extraction column (2) is connected to the upper inlet of the raffinate tank (24) through a pipeline; the upper inlet of the dilute solvent recovery column (3) is connected to the outlet of the dilute solvent recovery feed pump (15) through a pipeline, the upper outlet of the dilute solvent recovery column (3) is connected to the upper inlet of the solvent recovery reboiler I (8) through a pipeline, the lower outlet of the dilute solvent recovery column (3) is respectively connected to the lower inlet of the dilute solvent recovery reboiler (9) and the inlet of the dilute solvent recovery bottom pump (17) through a pipeline, and the upper outlet of the dilute solvent recovery reboiler (9) is connected to the lower inlet of the dilute solvent recovery column (3) through a pipeline; the middle inlet of the solvent recovery column (4) is connected to the outlet of the solvent recovery feed pump (16) through a pipeline, the upper inlet of the solvent recovery column (4) is connected to the outlet of the solvent recovery reflux pump (20) through a pipeline, the lower inlet of the solvent recovery column (4) is connected to the outlet of the solvent recovery reboiler II (12) through a pipeline, the upper outlet of the solvent recovery column (4) is connected to the upper inlet of the solvent recovery condenser (10) through a pipeline, and the lower outlet of the solvent recovery column (4) is connected to the inlet of the solvent recovery circulation pump (18) through a pipeline; the material inlet of the mother liquor heater (5) is communicated with the outlet of the mother liquor feed pump (13) through a pipeline, the heating side inlet of the mother liquor heater (5) is connected to the steam inlet pipeline, and the heating side outlet of the mother liquor heater (5) is connected to the condensate recovery pipeline;The feed inlet of the extractant heater (6) is connected to the outlet of the extractant feed pump (14) through a pipeline. The inlet of the heating side of the extractant heater (6) is connected to the steam inlet pipeline, and the outlet of the heating side of the extractant heater (6) is connected to the condensate recovery pipeline. The feed inlet of the desalted water heater (7) is connected to the desalted water pipeline. The inlet of the heating side of the desalted water heater (7) is connected to the steam inlet pipeline, and the outlet of the heating side of the desalted water heater (7) is connected to the condensate recovery pipeline. The outlet of the solvent recovery reboiler I (8) is connected to the top feed inlet of the dilute solvent recovery and stratification tank (26) through a pipeline. The inlet of the cooling side of the solvent recovery reboiler I (8) is connected to the circulating water inlet pipeline, and the outlet of the cooling side of the solvent recovery reboiler I (8) is connected to the circulating water return pipeline. The inlet of the heating side of the dilute solvent recovery reboiler (9) is connected to the steam inlet pipeline, and the outlet of the heating side of the dilute solvent recovery reboiler (9) is connected to the condensate recovery pipeline. The outlet of the solvent recovery condenser (10) is connected to the upper feed inlet of the solvent recovery column reflux tank (27) through a pipeline. The inlet of the cooling side of the solvent recovery condenser (10) is connected to the circulating water inlet pipeline, and the outlet of the cooling side of the solvent recovery condenser (10) is connected to the circulating water return pipeline. The inlet of the solvent recovery tail cooler (11) is connected to the upper outlet of the solvent recovery column reflux tank (27) through a pipeline. The outlet of the solvent recovery tail cooler (11) is connected to the solvent recovery vacuum pump (21) through a pipeline. The inlet of the cooling side of the solvent recovery tail cooler (11) is connected to the circulating water inlet pipeline, and the outlet of the cooling side of the solvent recovery tail cooler (11) is connected to the circulating water return pipeline. The upper feed inlet of the solvent recovery reboiler II (12) is connected to the outlet of the solvent recovery circulation pump (18) through a pipeline. The bottom outlet of the solvent recovery reboiler II (12) is connected to the inlet of the solvent recovery discharge pump (19) through a pipeline. The inlet of the heating side of the solvent recovery reboiler II (12) is connected to the steam inlet pipeline, and the outlet of the heating side of the solvent recovery reboiler II (12) is connected to the condensate recovery pipeline. The inlet of the mother liquor feed pump (13) is connected to the outlet of the mother liquor tank (22) through a pipeline. The inlet of the extractant feed pump (14) is connected to the bottom outlet of the extractant tank (23) through a pipeline. The inlet of the dilute solvent recovery feed pump (15) is connected to the bottom outlet of the raffinate tank (24) through a pipeline. The inlet of the solvent recovery feed pump (16) is connected to the bottom outlet of the extract solution tank (25) through a pipeline. The outlet of the dilute solvent recovery column bottom pump (17) is connected to the pipeline for wastewater treatment. The outlet of the solvent recovery discharge pump (19) is connected to the pipeline for the collection tank. The inlet of the solvent recovery reflux pump (20) is connected to the bottom outlet of the solvent recovery column reflux tank (27) through a pipeline. The outlet of the solvent recovery reflux pump (20) is connected to the upper inlet of the extractant tank (23) through a pipeline. The upper inlet of the mother liquor tank (22) is connected to the mother liquor pipeline. The upper inlet of the extractant tank (23) is connected to the isooctanol pipeline.The lower outlet of the extraction liquid tank (25) is connected to the upper inlet of the raffinate liquid tank (24) through a pipeline; the upper outlet of the dilute solvent recovery separator (26) is connected to the upper inlet of the extractant tank (23) through a pipeline, and the bottom outlet of the dilute solvent recovery separator (26) and the upper inlet of the dilute solvent recovery separator (26) form a circulation loop through a pipeline, and an outlet is provided at the middle position of the circulation loop and is connected to the upper inlet of the raffinate liquid tank (24) through a pipeline.;

[0023] The method for treating pentaerythritol mother liquor by using the above system is as follows:

[0024] 1. The pentaerythritol mother liquor is input into the mother liquor tank (22) through a pipeline for storage, pressurized by the mother liquor feed pump (13), and then enters the mother liquor heater (5). The temperature is controlled at 50 - 70 °C and it enters the upper part of the extraction tower (1). The liquid in the extractant tank (23) is pressurized by a pump and then enters the extractant heater (6). The temperature is controlled at 50 - 70 °C and it enters the lower part of the extraction tower (1). The liquid at the bottom of the extraction tower (1) enters the raffinate liquid tank (24), and the liquid at the top of the extraction tower (1) enters the stripping tower (2) at the bottom;

[0025] 2. Demineralized water enters the demineralized water heater (7). The temperature is controlled at 50 - 70 °C and it enters the upper part of the stripping tower (2). The liquid at the top of the stripping tower (2) enters the extraction liquid tank (25), and the liquid at the bottom of the stripping tower (2) enters the raffinate liquid tank (24);

[0026] 3. The liquid in the raffinate liquid tank (24) is pressurized by the dilute solvent recovery feed pump (15) and sent to the upper part of the dilute solvent recovery tower (3). The steam at the top of the dilute solvent recovery tower (3) enters the dilute solvent recovery condenser (10), and the condensate enters the dilute solvent recovery separator (26). The oil layer returns to the extractant tank (23) for recycling, and the water layer returns to the extraction liquid tank (25) to continue recovering the solvent therein. The dilute solvent recovery reboiler (9) at the lower part of the dilute solvent recovery tower (3) uses steam as a heat source for heating, and the wastewater with less solvent at the bottom of the tower is pressurized by the solvent recovery bottom pump (17) and sent out;

[0027] 4. The extraction liquid tank (25) is provided with a low-level water separator, and the separated water layer goes to the raffinate tank (24). The oil layer in the extraction liquid tank (25) is pressurized by the solvent recovery feed pump (16) and sent to the middle of the solvent recovery tower (4). The steam at the top of the solvent recovery tower (4) enters the solvent recovery condenser (10) and the solvent recovery tail cooler (11), and the condensate enters the solvent recovery tower reflux tank (27). After being pressurized by the solvent recovery reflux pump (20), a part of it flows back into the solvent recovery tower (4), and a part is sent to the extractant tank (23) for recycling. The liquid at the bottom of the solvent recovery tower (4) is pressurized by the solvent recovery circulation pump (18) and sent to the second solvent recovery reboiler (12). The second solvent recovery reboiler (12) uses steam as a heat source for heating. The heated gas-liquid phase enters the bottom of the solvent recovery tower (4), and high-boiling substances are taken out from the lower head of the second solvent recovery reboiler (12) and sent out by the solvent recovery discharge pump (19). The solvent recovery tower (4) operates under vacuum, and the solvent recovery vacuum pump (21) is used to evacuate it.

[0028] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A system for separating pentaerythritol and calcium formate from pentaerythritol mother liquor, characterized in that: Including an extraction tower (1), a stripping tower (2), a dilute solvent recovery tower (3), a solvent recovery tower (4), a demineralized water heater (7), a solvent recovery reboiler I (8), a dilute solvent recovery reboiler (9), a solvent recovery condenser (10), a solvent recovery tail condenser (11), a solvent recovery reboiler II (12), a mother liquor feed pump (13), an extractant feed pump (14), a dilute solvent recovery feed pump (15), a solvent recovery feed pump (16), a dilute solvent recovery bottom pump (17), a solvent recovery circulation pump (18), a solvent recovery discharge pump (19), a solvent recovery reflux pump (20), a solvent recovery vacuum pump (21), a mother liquor tank (22), an extractant tank (23), a raffinate tank (24), an extract liquid tank (25), a dilute solvent recovery decanter (26), a solvent recovery tower reflux tank (27); the upper inlet of the extraction tower (1) is connected to the mother liquor tank (22) through a pipeline and the mother liquor feed pump (13), the lower inlet opened on the extraction tower (1) is connected to the extractant tank (23) through a pipeline and the extractant feed pump (14), the upper outlet of the extraction tower (1) is connected to the lower inlet of the stripping tower (2) through a pipeline, and the lower outlet of the extraction tower (1) is connected to the inlet opened on the raffinate tank (24) through a pipeline; the upper inlet of the stripping tower (2) is connected to the outlet of the demineralized water heater (7) through a pipeline, the upper outlet of the stripping tower (2) is connected to the upper inlet of the extract liquid tank (25) through a pipeline, and the lower outlet of the stripping tower (2) is connected to the upper inlet of the raffinate tank (24) through a pipeline; the upper inlet of the dilute solvent recovery tower (3) is connected to the outlet of the dilute solvent recovery feed pump (15) through a pipeline, the upper outlet of the dilute solvent recovery tower (3) is connected to the upper inlet of the solvent recovery reboiler I (8) through a pipeline, the lower outlet of the dilute solvent recovery tower (3) is respectively connected to the lower inlet of the dilute solvent recovery reboiler (9) and the inlet of the dilute solvent recovery bottom pump (17), and the upper outlet of the dilute solvent recovery reboiler (9) is connected to the lower inlet of the dilute solvent recovery tower (3) through a pipeline; the middle inlet of the solvent recovery tower (4) is connected to the outlet of the solvent recovery feed pump (16) through a pipeline, the upper inlet of the solvent recovery tower (4) is connected to the outlet of the solvent recovery reflux pump (20) through a pipeline, the lower inlet of the solvent recovery tower (4) is connected to the outlet of the solvent recovery reboiler II (12) through a pipeline, the upper outlet of the solvent recovery tower (4) is connected to the upper inlet of the solvent recovery condenser (10) through a pipeline, and the lower outlet of the solvent recovery tower (4) is connected to the inlet of the solvent recovery circulation pump (18) through a pipeline; the material inlet of the mother liquor heater (5) is connected to the outlet of the mother liquor feed pump (13) through a pipeline, the heating side inlet of the mother liquor heater (5) is connected to the steam inlet pipeline, and the heating side outlet of the mother liquor heater (5) is connected to the condensate recovery pipeline;The feed inlet of the extractant heater (6) is connected to the outlet of the extractant feed pump (14) through a pipeline. The inlet of the heating side of the extractant heater (6) is connected to the steam inlet pipeline, and the outlet of the heating side of the extractant heater (6) is connected to the condensate recovery pipeline; the feed inlet of the demineralized water heater (7) is connected to the demineralized water pipeline. The inlet of the heating side of the demineralized water heater (7) is connected to the steam inlet pipeline, and the outlet of the heating side of the demineralized water heater (7) is connected to the condensate recovery pipeline; the outlet of the solvent recovery reboiler I (8) is connected to the top feed inlet of the dilute solvent recovery and stratification tank (26) through a pipeline. The inlet of the cooling side of the solvent recovery reboiler I (8) is connected to the circulating water inlet pipeline, and the outlet of the cooling side of the solvent recovery reboiler I (8) is connected to the circulating water return pipeline; the inlet of the heating side of the dilute solvent recovery reboiler (9) is connected to the steam inlet pipeline, and the outlet of the heating side of the dilute solvent recovery reboiler (9) is connected to the condensate recovery pipeline; the outlet of the solvent recovery condenser (10) is connected to the upper feed inlet of the solvent recovery column reflux tank (27) through a pipeline. The inlet of the cooling side of the solvent recovery condenser (10) is connected to the circulating water inlet pipeline, and the outlet of the cooling side of the solvent recovery condenser (10) is connected to the circulating water return pipeline; the inlet of the solvent recovery tail cooler (11) is connected to the upper outlet of the solvent recovery column reflux tank (27) through a pipeline. The outlet of the solvent recovery tail cooler (11) is connected to the solvent recovery vacuum pump (21) through a pipeline. The inlet of the cooling side of the solvent recovery tail cooler (11) is connected to the circulating water inlet pipeline, and the outlet of the cooling side of the solvent recovery tail cooler (11) is connected to the circulating water return pipeline; the upper feed inlet of the solvent recovery reboiler II (12) is connected to the outlet of the solvent recovery circulation pump (18) through a pipeline. The bottom outlet of the solvent recovery reboiler II (12) is connected to the inlet of the solvent recovery discharge pump (19) through a pipeline. The inlet of the heating side of the solvent recovery reboiler II (12) is connected to the steam inlet pipeline, and the outlet of the heating side of the solvent recovery reboiler II (12) is connected to the condensate recovery pipeline; the inlet of the mother liquor feed pump (13) is connected to the outlet of the mother liquor tank (22) through a pipeline; the inlet of the extractant feed pump (14) is connected to the bottom outlet of the extractant tank (23) through a pipeline; the inlet of the dilute solvent recovery feed pump (15) is connected to the bottom outlet of the raffinate tank (24) through a pipeline; the inlet of the solvent recovery feed pump (16) is connected to the bottom outlet of the extract solution tank (25) through a pipeline; the outlet of the dilute solvent recovery column bottom pump (17) is connected to the pipeline for wastewater treatment; the outlet of the solvent recovery discharge pump (19) is connected to the pipeline for collecting tank; the inlet of the solvent recovery reflux pump (20) is connected to the bottom outlet of the solvent recovery column reflux tank (27) through a pipeline. The outlet of the solvent recovery reflux pump (20) is connected to the upper inlet of the extractant tank (23) through a pipeline; the upper inlet of the mother liquor tank (22) is connected to the mother liquor pipeline; the upper inlet of the extractant tank (23) is connected to the isooctanol pipeline;The lower outlet of the extraction liquid tank (25) is connected to the upper inlet of the raffinate liquid tank (24) through a pipeline; the upper outlet of the dilute solvent recovery separator (26) is connected to the upper inlet of the extractant tank (23) through a pipeline, and the bottom outlet of the dilute solvent recovery separator (26) and the upper inlet of the dilute solvent recovery separator (26) form a circulation loop through a pipeline, and an outlet is provided at the middle position of the circulation loop and is connected to the upper inlet of the raffinate liquid tank (24) through a pipeline; A mother liquor heater (5) is provided between the extraction tower (1) and the mother liquor feed pump (13); An extractant heater (6) is provided between the extraction tower (1) and the extractant feed pump (14).

2. The system for separating pentaerythritol and calcium formate from pentaerythritol mother liquor according to claim 1, characterized in that: Valves are provided on all pipelines.

3. A method for separating pentaerythritol and calcium formate using the system for separating pentaerythritol and calcium formate according to any one of claims 1-2, characterized in that: It includes the following steps: The first step: The pentaerythritol mother liquor is input into the mother liquor tank (22) through a pipeline for storage, pressurized by the mother liquor feed pump (13), and then enters the mother liquor heater (5). After controlling the temperature to 50-70°C, it enters the upper part of the extraction tower (1). The liquid in the extractant tank (23) is pressurized by a pump and then enters the extractant heater (6). After controlling the temperature to 50-70°C, it enters the lower part of the extraction tower (1). The liquid at the bottom of the extraction tower (1) enters the raffinate tank (24), and the liquid at the top of the extraction tower (1) enters the bottom of the stripping tower (2); The second step: Demineralized water enters the demineralized water heater (7). After controlling the temperature to 50-70°C, it enters the upper part of the stripping tower (2). The top liquid of the stripping tower (2) enters the extract liquid tank (25), and the bottom liquid of the stripping tower (2) enters the raffinate tank (24); The third step: The liquid in the raffinate tank (24) is pressurized by the dilute solvent recovery feed pump (15) and then sent to the upper part of the dilute solvent recovery tower (3). The steam at the top of the dilute solvent recovery tower (3) enters the dilute solvent recovery condenser (10), and the condensate enters the dilute solvent recovery separator (26). The oil layer returns to the extractant tank (23) for recycling, and the water layer returns to the extract liquid tank (25) to continue recovering the solvent therein. The lower part of the dilute solvent recovery tower (3), the dilute solvent recovery reboiler (9) uses steam as a heat source for heating. The wastewater with less solvent at the bottom of the tower is pressurized by the solvent recovery tower bottom pump (17) and then sent out; The fourth step: A low-level water separation is set in the extract liquid tank (25), and the separated water layer goes to the raffinate tank (24). The oil layer in the extract liquid tank (25) is pressurized by the solvent recovery feed pump (16) and then sent to the middle part of the solvent recovery tower (4). The steam at the top of the solvent recovery tower (4) enters the solvent recovery condenser (10) and the solvent recovery tail cooler (11). The condensate enters the solvent recovery tower reflux tank (27), and after being pressurized by the solvent recovery reflux pump (20), a part of it returns to the solvent recovery tower (4), and a part is sent to the extractant tank (23) for recycling. The bottom liquid of the solvent recovery tower (4) is pressurized by the solvent recovery circulation pump (18) and then sent to the solvent recovery reboiler II (12). The solvent recovery reboiler II (12) uses steam as a heat source for heating. The heated gas-liquid phase enters the bottom of the solvent recovery tower (4). The high-boiling substances are extracted from the lower head of the solvent recovery reboiler II (12) and sent out by the solvent recovery discharge pump (19). The solvent recovery tower (4) operates under vacuum, and the solvent recovery vacuum pump (21) is used to evacuate it.

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