Phenol-acetone preparation method based on regulation and control of pH value of neutralization system
By controlling the pH value of the neutralization system and controlling the pH value of the neutralization tank and the washing tank during the preparation of phenol acetone, the problems of rising tar content and increasing wastewater volume caused by improper pH value in the prior art are solved, and the effect of reducing production costs and improving market competitiveness is achieved.
Patent Information
- Application Number
- CN202411777411.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-05
- Publication Date
- 2025-03-11
AI Technical Summary
In the existing phenol acetone preparation technology, too low or too high pH of the distillation feed will lead to an increase in tar content, equipment corrosion, increased wastewater volume and decreased heat exchanger efficiency, affecting production costs and market competitiveness.
By regulating the pH of the neutralization system, the pH value of the neutralization tank is controlled to be between 6.5 and 7.0, and the pH value of the neutralization washing tank is between 5.0 and 5.8, the separation of phenol and the recombinant components is achieved, and the tar content and wastewater volume are reduced.
On the premise of ensuring excellent products, the production cost is reduced, the online operation time of the distillation heat exchanger is extended, the amount of wastewater and tar is reduced, and the market competitiveness of the product is improved.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the field of phenol acetone preparation, and in particular to a phenol acetone preparation method based on regulating the pH value of a neutralization system. Background Art
[0002] Phenol-acetone technology uses the reaction of cumene and oxygen to produce phenol and acetone. CHP (cumene hydroperoxide) produced from cumene and oxygen is purified by the concentration system and then decomposed into phenol and acetone under the action of sulfuric acid catalyst, containing impurities such as AMS (α-methylstyrene), CP (cumylphenol), AP (acetophenone), and sulfuric acid. After separation by the distillation system, phenol and acetone products are further obtained.
[0003] Among them, distillation separation is one of the key steps in the preparation of high-purity phenol and acetone. If the pH value in the distillation feed is too low, phenol will combine with a large amount of heavy components, resulting in an increase in the tar content. At the same time, too low a pH value will also cause pipeline corrosion, thus affecting the service life of the equipment. Lowering the pH value will increase the use of sulfuric acid, which will greatly increase the salt content in the wastewater, affect the neutralization interface, and then lead to an increase in the amount of wastewater. Although an excessively high pH value is conducive to a decrease in tar production, it will increase the salt content in the heat exchanger, resulting in a decrease in the efficiency of the heat exchanger and an increase in the use of steam. At the same time, an excessively high pH value will also increase the use of NaOH and the amount of wastewater treated. A large number of heat exchangers have salt accumulation, which will shorten the online operation cycle of the phenol-acetone unit and increase the frequency of daily switching and flushing operations.
[0004] Research and practice on how to control the influence of neutralization pH value on the operation cycle of distillation system. This process reduces the production cost of products and improves the market competitiveness of products while ensuring that the products are of high quality. Summary of the invention
[0005] In view of the above-mentioned existing technical problems, the present invention aims to provide an optimized method for preparing acetone phenol, which can reduce the amount of wastewater and tar in the production process, reduce the corrosion damage of salt accumulation to each distillation unit, reduce the production cost of the product while ensuring that the product is a high-quality product, and improve the market competitiveness of the product.
[0006] The invention discloses a method for preparing phenol acetone based on regulating the pH value of a neutralization system, and the preparation method comprises the following steps:
[0007] S1 Oxidative decomposition: cumene and the recovered product from the concentration tower are introduced into the fixed bed reactor in the oxidation zone for oxidation reaction to generate cumene hydroperoxide. The cumene hydroperoxide is concentrated in the concentration tower and introduced into the decomposer for the first decomposition reaction to obtain a decomposition liquid. The decomposition liquid is pumped into the secondary decomposition reactor by the decomposition discharge pump to perform the next decomposition reaction to obtain a decomposition discharge.
[0008] S2 Neutralization separation: The decomposed material obtained in step S1 is cooled in a neutralization feed cooler and then fed into a neutralization system, the pH value of the neutralization system is adjusted, and a neutralization reaction is performed; the organic phase of the neutralization tank and the salt solution circulating in the neutralization water washing tank are mixed in a static mixer and fed into the neutralization water washing tank; the sodium phenolate in the organic phase of the neutralization tank is extracted by the water phase of the neutralization water washing tank, the water phase is circulated by the neutralization water washing circulation pump, and the organic matter in the neutralization water washing tank overflows into a concentrator to remove the entrained water, thereby obtaining an acetone-phenol organic mixture;
[0009] S3 product purification: the acetone-phenol organic mixture obtained in step S2 overflows into the distillation feed tank, and passes through the crude acetone tower and the refined acetone tower in sequence to obtain high-purity acetone; the kettle liquid coming out of the crude acetone tower enters the crude phenol tower, and then passes through the deweighting tower, the dehydrocarbon removal tower, the resin processor and the refined phenol tower in sequence to obtain high-purity phenol after separation.
[0010] Preferably, in the S1 oxidative decomposition step, the concentration of cumene hydroperoxide after concentration is in the range of 80 to 85%.
[0011] Preferably, the catalyst used in the first decomposition reaction is concentrated sulfuric acid with a mass fraction of 98-99%.
[0012] Preferably, in the neutralization and separation step S2, sodium phenolate and sodium hydroxide are used in the regulating neutralization system; wherein the mass ratio of sodium phenolate to sodium hydroxide is 1:(0.3-0.5).
[0013] Preferably, in the neutralization and separation step S2, the pH value of the neutralization tank is controlled at 5.0 to 5.8.
[0014] Preferably, in the neutralization and separation step S2, the pH value of the neutralization water washing tank is controlled at 6.5 to 7.0.
[0015] Preferably, in the S3 product purification step, a feed preheater is provided in the crude acetone tower, and the feed preheater is heated by low-pressure steam, and the amount of low-pressure steam used is 11.73 to 11.94 t / h.
[0016] Preferably, in the S3 product purification step, a reboiler is provided at the bottom of the crude acetone tower, and high-pressure steam is contained in the reboiler, and the amount of high-pressure steam used is 23.17 to 23.56 t / h.
[0017] Preferably, in the S3 product purification step, a reboiler is provided in the crude phenol tower, and the reboiler is heated by medium-pressure steam, and the amount of medium-pressure steam used is 9.71 to 9.80 t / h.
[0018] Preferably, in the S3 product purification step, a reboiler is provided in the deweighting tower, and the reboiler uses high-pressure steam, and the amount of high-pressure steam used is 3.05 to 3.13 t / h.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] The present invention provides a phenol acetone preparation method based on regulating the pH value of a neutralization system. During the entire preparation process, by regulating the pH value of a neutralization tank in the neutralization system to 6.5-7.0 and controlling the pH value of a neutralization water washing tank to be between 5.0-5.8, phenol can be separated from heavy components, the purity of phenol can be improved, and the tar content can be reduced; the salt content in wastewater can be ensured to be at a relatively low level, the neutralization boundary can be ensured, and the amount of wastewater can be reduced; when the tar content of wastewater is reduced, the online operation time of a distillation heat exchanger can be extended to 7.1-7.5 months. DETAILED DESCRIPTION
[0021] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.
[0022] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.
[0023] Example 1: A method for preparing phenol acetone based on regulating the pH value of a neutralization system, comprising the following steps:
[0024] S1 Oxidative decomposition: isopropylbenzene and the recovered product of the concentration tower are introduced into the fixed bed reactor of the oxidation zone together for oxidation reaction to generate isopropylbenzene hydroperoxide, and the generated isopropylbenzene hydroperoxide is introduced into the topmost tower plate as reflux of the primary concentration tower; the reboiler of the primary concentration tower is heated by the gas phase at the top of the dehydrocarbon removal tower, and the bottom liquid flows into the secondary concentration tower by gravity, so that the concentration of isopropylbenzene hydroperoxide after concentration is 80%; then the concentrated isopropylbenzene hydroperoxide is introduced into the decomposer for the first decomposition reaction, and the acidification catalyst used in the acidification reaction is concentrated sulfuric acid with a concentration of 98% to obtain a decomposition liquid, which is pumped into the secondary decomposition reactor by a decomposition discharge pump for the next decomposition reaction to obtain a decomposition discharge.
[0025] S2 Neutralization separation: the decomposed effluent obtained in step S1 is cooled in a neutralization feed cooler and then fed into a neutralization tank, the pH value of the neutralization tank is adjusted to 5.0-5.2, and a neutralization reaction occurs with phenol and sodium hydroxide in the neutralization tank to generate sodium salt, phenol and water; wherein the mass ratio of sodium phenolate to sodium hydroxide is 1:0.3; the organic phase of the neutralization tank and the salt solution circulated in the neutralization water washing tank are mixed in a static mixer and fed into the neutralization water washing tank, and the pH value of the neutralization water washing tank is controlled to be 6.5-7.0; the sodium phenolate in the organic phase of the neutralization tank is extracted by the water phase of the neutralization water washing tank, the water phase is circulated by the neutralization water washing circulation pump, the organic matter in the neutralization water washing tank overflows to the aggregator to remove the entrained water, and the aggregated water is returned to the neutralization tank to obtain an acetone-phenol organic mixture.
[0026] S3 product purification: The acetone-phenol organic mixture obtained in step S2 overflows into the distillation feed tank, and the acetone-phenol organic mixture in the distillation feed tank is heated by a crude acetone tower feed preheater, wherein the feed preheater is heated by low-pressure steam, and the steam amount used is 11.73 t / h. After being heated, the organic mixture enters the middle of the crude acetone tower. The crude acetone tower is a normal pressure tower, and the gas at the top of the tower is used as part of the feed of the refined acetone tower. The organic phase at the bottom of the tower is sent to the reboiler at the bottom of the crude acetone tower through the discharge pump of the crude acetone tower kettle. The reboiler is heated by high-pressure steam with a steam volume of 23.17 t / h. After being heated by the reboiler, it enters the reflux tank of the crude acetone tower. The gas from the top of the acetone tower and the gas phase from the reflux tank of the crude acetone tower are combined and enter the 66th tower plate of the refined acetone tower for subsequent distillation. The acetone product is taken out from the side line at the 6th tower plate, cooled by the refined acetone tower product cooler, and then enters the acetone product tank to obtain high-purity acetone.
[0027] The discharge pump of the crude acetone tower sends the other part to the crude phenol tower. The bottom discharge of the crude phenol tower is sent to the dehydrogenation tower through the discharge pump of the tower, and is heated by high-pressure steam in the reboiler of the dehydrogenation tower. The steam used is 3.05t / h. The gas phase at the top of the dehydrogenation tower directly enters the crude phenol tower. The bottom discharge is cooled by the phenol tar cooler and enters the phenol tar tank. The gas phase in the crude acetone tower is further cooled by the top condenser of the crude phenol tower after heat exchange in the reboiler of the crude phenol tower. The gas phase enters the steam injection system of the crude phenol tower and is sent to the dehydrogenation tower. The reboiler is heated by medium-pressure steam, and the steam consumption is 9.71t / h. After separation in the resin processor and the refined phenol tower, high-purity phenol is obtained.
[0028] Embodiment 2: A method for preparing phenol acetone based on regulating the pH value of a neutralization system, comprising the following steps:
[0029] S1 Oxidative decomposition: isopropylbenzene and the recovered product of the concentration tower are introduced into the fixed bed reactor of the oxidation zone together for oxidation reaction to generate isopropylbenzene hydroperoxide, and the generated isopropylbenzene hydroperoxide is introduced into the topmost tower plate as reflux of the primary concentration tower; the reboiler of the primary concentration tower is heated by the gas phase at the top of the dehydrocarbon removal tower, and the bottom liquid flows into the secondary concentration tower by gravity, so that the concentration of isopropylbenzene hydroperoxide after concentration is 81%; then the concentrated isopropylbenzene hydroperoxide is introduced into the decomposer for the first decomposition reaction, and the acidification catalyst used in the acidification reaction is concentrated sulfuric acid with a concentration of 98.2% to obtain a decomposition liquid, which is pumped into the secondary decomposition reactor by a decomposition discharge pump for the next decomposition reaction to obtain a decomposition discharge.
[0030] S2 Neutralization separation: the decomposed effluent obtained in step S1 is cooled in a neutralization feed cooler and then fed into a neutralization tank, the pH value of the neutralization tank is adjusted to 5.2-5.4, and a neutralization reaction occurs with phenol and sodium hydroxide in the neutralization tank to generate sodium salt, phenol and water; wherein the mass ratio of sodium phenolate to sodium hydroxide is 1:0.35; the organic phase of the neutralization tank and the salt solution circulated in the neutralization water washing tank are mixed in a static mixer and fed into the neutralization water washing tank, and the pH value of the neutralization water washing tank is controlled to be 6.5-7.0; the sodium phenolate in the organic phase of the neutralization tank is extracted by the water phase of the neutralization water washing tank, the water phase is circulated by the neutralization water washing circulation pump, the organic matter in the neutralization water washing tank overflows to the aggregator to remove the entrained water, and the aggregated water is returned to the neutralization tank to obtain an acetone-phenol organic mixture.
[0031] S3 product purification: The acetone-phenol organic mixture obtained in step S2 overflows into the distillation feed tank, and the acetone-phenol organic mixture in the distillation feed tank is heated by a crude acetone tower feed preheater, wherein the feed preheater is heated by low-pressure steam, and the steam amount used is 11.77 t / h. After being heated, the organic mixture enters the middle of the crude acetone tower. The crude acetone tower is a normal pressure tower, and the gas at the top of the tower is used as part of the feed of the refined acetone tower. The organic phase at the bottom of the tower is sent to the reboiler at the bottom of the crude acetone tower through the discharge pump of the crude acetone tower. The reboiler is heated by high-pressure steam with a steam volume of 23.28 t / h. After being heated by the reboiler, it enters the reflux tank of the crude acetone tower. The gas from the top of the acetone tower and the gas phase from the reflux tank of the crude acetone tower are combined and enter the 66th tower plate of the refined acetone tower for subsequent distillation. The acetone product is taken out from the side line at the 6th tower plate, cooled by the refined acetone tower product cooler, and then enters the acetone product tank to obtain high-purity acetone.
[0032] The discharge pump of the crude acetone tower sends the other part to the crude phenol tower. The bottom discharge of the crude phenol tower is sent to the dehydrogenation tower through the discharge pump of the tower, and is heated by high-pressure steam in the reboiler of the dehydrogenation tower. The steam used is 3.06t / h. The gas phase at the top of the dehydrogenation tower directly enters the crude phenol tower. The bottom discharge is cooled by the phenol tar cooler and enters the phenol tar tank. The gas phase in the crude acetone tower is further cooled by the top condenser of the crude phenol tower after heat exchange in the reboiler of the crude phenol tower. The gas phase enters the steam injection system of the crude phenol tower and is sent to the dehydrogenation tower. The reboiler is heated by medium-pressure steam, and the steam consumption is 9.72t / h. After separation in the resin processor and the refined phenol tower, high-purity phenol is obtained.
[0033] Embodiment 3: A method for preparing phenol acetone based on regulating the pH value of the neutralization system, comprising the following steps:
[0034] S1 Oxidative decomposition: isopropylbenzene and the recovered product of the concentration tower are introduced into the fixed bed reactor of the oxidation zone together for oxidation reaction to generate isopropylbenzene hydroperoxide, and the generated isopropylbenzene hydroperoxide is introduced into the topmost tower plate as reflux of the primary concentration tower; the reboiler of the primary concentration tower is heated by the gas phase at the top of the dehydrocarbon removal tower, and the bottom liquid flows into the secondary concentration tower by gravity, so that the concentration of isopropylbenzene hydroperoxide after concentration is 82%; then the concentrated isopropylbenzene hydroperoxide is introduced into the decomposer for the first decomposition reaction, and the acidification catalyst used in the acidification reaction is concentrated sulfuric acid with a concentration of 98.4% to obtain a decomposition liquid, which is pumped into the secondary decomposition reactor by a decomposition discharge pump for the next decomposition reaction to obtain a decomposition discharge.
[0035] S2 Neutralization separation: the decomposed effluent obtained in step S1 is cooled in a neutralization feed cooler and then fed into a neutralization tank, the pH value of the neutralization tank is adjusted to 5.4-5.6, and a neutralization reaction occurs with phenol and sodium hydroxide in the neutralization tank to generate sodium salt, phenol and water; wherein the mass ratio of sodium phenolate to sodium hydroxide is 1:0.4; the organic phase of the neutralization tank and the salt solution circulated in the neutralization water washing tank are mixed in a static mixer and fed into the neutralization water washing tank, and the pH value of the neutralization water washing tank is controlled to be 6.5-7.0; the sodium phenolate in the organic phase of the neutralization tank is extracted by the water phase of the neutralization water washing tank, the water phase is circulated by the neutralization water washing circulation pump, the organic matter in the neutralization water washing tank overflows to the aggregator to remove the entrained water, and the aggregated water is returned to the neutralization tank to obtain an acetone-phenol organic mixture.
[0036] S3 product purification: The acetone-phenol organic mixture obtained in step S2 overflows into the distillation feed tank, and the acetone-phenol organic mixture in the distillation feed tank is heated by a crude acetone tower feed preheater, wherein the feed preheater is heated by low-pressure steam, and the steam amount used is 11.83 t / h. After being heated, the organic mixture enters the middle of the crude acetone tower. The crude acetone tower is a normal pressure tower, and the gas at the top of the tower is used as part of the feed of the refined acetone tower. The organic phase at the bottom of the tower is sent to the reboiler at the bottom of the crude acetone tower through the discharge pump of the crude acetone tower kettle. The reboiler is heated by high-pressure steam with a steam volume of 23.34 t / h. After being heated by the reboiler, it enters the reflux tank of the crude acetone tower. The gas from the top of the acetone tower and the gas phase from the reflux tank of the crude acetone tower are combined and enter the 66th tower plate of the refined acetone tower for subsequent distillation. The acetone product is taken out from the side line at the 6th tower plate, cooled by the refined acetone tower product cooler, and then enters the acetone product tank to obtain high-purity acetone.
[0037] The discharge pump of the crude acetone tower sends the other part to the crude phenol tower. The bottom discharge of the crude phenol tower is sent to the dehydrogenation tower through the discharge pump of the tower, and is heated by high-pressure steam in the reboiler of the dehydrogenation tower. The steam used is 3.08t / h. The gas phase at the top of the dehydrogenation tower directly enters the crude phenol tower. The bottom discharge is cooled by the phenol tar cooler and enters the phenol tar tank. The gas phase in the crude acetone tower is further cooled by the top condenser of the crude phenol tower after heat exchange in the reboiler of the crude phenol tower. The gas phase enters the steam injection system of the crude phenol tower and is sent to the dehydrogenation tower. The reboiler is heated by medium-pressure steam, and the steam consumption is 9.74t / h. After separation in the resin processor and the refined phenol tower, high-purity phenol is obtained.
[0038] Example 4: A method for preparing phenol acetone based on regulating the pH value of a neutralization system, comprising the following steps:
[0039] S1 Oxidative decomposition: isopropylbenzene and the recovered product of the concentration tower are introduced into the fixed bed reactor of the oxidation zone together for oxidation reaction to generate isopropylbenzene hydroperoxide, and the generated isopropylbenzene hydroperoxide is introduced into the topmost tower plate as reflux of the primary concentration tower; the reboiler of the primary concentration tower is heated by the gas phase at the top of the dehydrocarbon removal tower, and the bottom liquid flows into the secondary concentration tower by gravity, so that the concentration of isopropylbenzene hydroperoxide after concentration is 83%; then the concentrated isopropylbenzene hydroperoxide is introduced into the decomposer for the first decomposition reaction, and the acidification catalyst used in the acidification reaction is concentrated sulfuric acid with a concentration of 98.7% to obtain a decomposition liquid, which is pumped into the secondary decomposition reactor by a decomposition discharge pump for the next decomposition reaction to obtain a decomposition discharge.
[0040] S2 Neutralization separation: the decomposed effluent obtained in step S1 is cooled in a neutralization feed cooler and then fed into a neutralization tank, the pH value of the neutralization tank is adjusted to 5.6-5.7, and a neutralization reaction occurs with phenol and sodium hydroxide in the neutralization tank to generate sodium salt, phenol and water; wherein the mass ratio of sodium phenolate to sodium hydroxide is 1:0.45; the organic phase of the neutralization tank and the salt solution circulated in the neutralization water washing tank are mixed in a static mixer and fed into the neutralization water washing tank, and the pH value of the neutralization water washing tank is controlled to be 6.5-7.0; the sodium phenolate in the organic phase of the neutralization tank is extracted by the water phase of the neutralization water washing tank, the water phase is circulated by the neutralization water washing circulation pump, the organic matter in the neutralization water washing tank overflows to the aggregator to remove the entrained water, and the aggregated water is returned to the neutralization tank to obtain an acetone-phenol organic mixture.
[0041] S3 product purification: The acetone-phenol organic mixture obtained in step S2 overflows into the distillation feed tank, and the acetone-phenol organic mixture in the distillation feed tank is heated by a crude acetone tower feed preheater, wherein the feed preheater is heated by low-pressure steam, and the steam amount used is 11.86 t / h. After being heated, the organic mixture enters the middle of the crude acetone tower. The crude acetone tower is a normal pressure tower, and the gas at the top of the tower is used as part of the feed of the refined acetone tower. The organic phase at the bottom of the tower is sent to the reboiler at the bottom of the crude acetone tower through the discharge pump of the crude acetone tower. The reboiler is heated by high-pressure steam with a steam volume of 23.43 t / h. After being heated by the reboiler, it enters the reflux tank of the crude acetone tower. The gas from the top of the acetone tower and the gas phase from the reflux tank of the crude acetone tower are combined and enter the 66th tower plate of the refined acetone tower for subsequent distillation. The acetone product is taken out from the side line at the 6th tower plate, cooled by the refined acetone tower product cooler, and enters the acetone product tank to obtain high-purity acetone.
[0042] The discharge pump of the crude acetone tower sends the other part to the crude phenol tower. The bottom discharge of the crude phenol tower is sent to the dehydrogenation tower through the discharge pump of the tower, and is heated by high-pressure steam in the reboiler of the dehydrogenation tower. The steam used is 3.11t / h. The gas phase at the top of the dehydrogenation tower directly enters the crude phenol tower. The bottom discharge is cooled by the phenol tar cooler and enters the phenol tar tank. The gas phase in the crude acetone tower is further cooled by the top condenser of the crude phenol tower after heat exchange in the reboiler of the crude phenol tower. The gas phase enters the steam injection system of the crude phenol tower and is sent to the dehydrogenation tower. The reboiler is heated by medium-pressure steam, and the steam consumption is 9.75t / h. After separation in the resin processor and the refined phenol tower, high-purity phenol is obtained.
[0043] Example 5: A method for preparing phenol acetone based on regulating the pH value of the neutralization system, comprising the following steps:
[0044] S1 Oxidative decomposition: isopropylbenzene and the recovered product of the concentration tower are introduced into the fixed bed reactor of the oxidation zone together for oxidation reaction to generate isopropylbenzene hydroperoxide, and the generated isopropylbenzene hydroperoxide is introduced into the topmost tower plate as reflux of the first-stage concentration tower; the reboiler of the first-stage concentration tower is heated by the gas phase at the top of the dehydrocarbon removal tower, and the bottom liquid flows into the second-stage concentration tower by gravity, so that the concentration of isopropylbenzene hydroperoxide after concentration is 85%; then the concentrated isopropylbenzene hydroperoxide is introduced into the decomposer for the first decomposition reaction, and the acidification catalyst used in the acidification reaction is concentrated sulfuric acid with a concentration of 99% to obtain a decomposition liquid, which is pumped into the second-stage decomposition reactor by a decomposition discharge pump for the next decomposition reaction to obtain a decomposition discharge.
[0045] S2 Neutralization separation: the decomposed effluent obtained in step S1 is cooled in a neutralization feed cooler and then fed into a neutralization tank, the pH value of the neutralization tank is adjusted to 5.8-6.0, and a neutralization reaction occurs with phenol and sodium hydroxide in the neutralization tank to generate sodium salt, phenol and water; wherein the mass ratio of sodium phenolate to sodium hydroxide is 1:0.5; the organic phase of the neutralization tank and the salt solution circulated in the neutralization water washing tank are mixed in a static mixer and fed into the neutralization water washing tank, and the pH value of the neutralization water washing tank is controlled to be 6.5-7.0; the sodium phenolate in the organic phase of the neutralization tank is extracted by the water phase of the neutralization water washing tank, the water phase is circulated by the neutralization water washing circulation pump, the organic matter in the neutralization water washing tank overflows to the aggregator to remove the entrained water, and the aggregated water is returned to the neutralization tank to obtain an acetone-phenol organic mixture.
[0046] S3 product purification: The acetone-phenol organic mixture obtained in step S2 overflows into the distillation feed tank, and the acetone-phenol organic mixture in the distillation feed tank is heated by a crude acetone tower feed preheater, wherein the feed preheater is heated by low-pressure steam, and the steam amount used is 11.94 t / h. After being heated, the organic mixture enters the middle of the crude acetone tower. The crude acetone tower is a normal pressure tower, and the gas at the top of the tower is used as part of the feed of the refined acetone tower. The organic phase at the bottom of the tower is sent to the reboiler at the bottom of the crude acetone tower through the discharge pump of the crude acetone tower. The reboiler is heated by high-pressure steam with a steam volume of 23.56 t / h. After being heated by the reboiler, it enters the reflux tank of the crude acetone tower. The gas from the top of the acetone tower and the gas phase from the reflux tank of the crude acetone tower are combined and enter the 66th tower plate of the refined acetone tower for subsequent distillation. The acetone product is taken out from the side line at the 6th tower plate, cooled by the refined acetone tower product cooler, and then enters the acetone product tank to obtain high-purity acetone.
[0047] The discharge pump of the crude acetone tower sends the other part to the crude phenol tower. The bottom discharge of the crude phenol tower is sent to the dehydrogenation tower through the discharge pump of the tower, and is heated by high-pressure steam in the reboiler of the dehydrogenation tower. The steam used is 3.13t / h. The gas phase at the top of the dehydrogenation tower directly enters the crude phenol tower. The bottom discharge is cooled by the phenol tar cooler and enters the phenol tar tank. The gas phase in the crude acetone tower is further cooled by the top condenser of the crude phenol tower after heat exchange in the reboiler of the crude phenol tower. The gas phase enters the steam injection system of the crude phenol tower and is sent to the dehydrogenation tower. The reboiler is heated by medium-pressure steam, and the steam consumption is 9.80t / h. After separation in the resin processor and the refined phenol tower, high-purity phenol is obtained.
[0048] Example 6: The pH value of the neutralizer in Example 1 is controlled between 5.0 and 5.8, and the pH value of the neutralizer water washing tank is adjusted to 6.5 to 6.7. The remaining steps and parameters are the same as in Example 1.
[0049] Example 7: The pH value of the neutralizer in Example 2 is controlled between 5.0 and 5.8, and the pH value of the neutralizer water washing tank is adjusted to 6.6 to 6.8. The remaining steps and parameters are the same as in Example 2.
[0050] Example 8: The pH value of the neutralizer in Example 3 is controlled between 5.0 and 5.8, and the pH value of the neutralizer water washing tank is adjusted to 6.7 to 6.9. The remaining steps and parameters are the same as in Example 3.
[0051] Example 9: The pH value of the neutralizer in Example 4 is controlled between 5.0 and 5.8, and the pH value of the neutralizer water washing tank is adjusted to 6.8 to 7.0. The remaining steps and parameters are the same as in Example 4.
[0052] Example 10: The pH value of the neutralizer in Example 5 is controlled between 5.0 and 5.8, and the pH value of the neutralizer water washing tank is adjusted to 7.0-7.2. The remaining steps and parameters are the same as in Example 5.
[0053] The pH value of the neutralizer water washing tank was controlled between 6.5 and 7.0, the pH value of the neutralizer was adjusted, and the online time of each distillation unit, phenol production, acetone production, wastewater volume and tar volume were tested. The test results are shown as follows:
[0054] Table 1
[0055]
[0056]
[0057] It can be seen from the test data in Table 1 that when the pH value of the neutralizer is controlled at 6.5-7.0, by adjusting the pH value of the neutralizer, it can be found that when the pH value of the neutralizer water washing tank is 5.0-5.8, the continuous working days of the crude acetone tower feed preheater are all above 40 hours; the continuous working days of the crude acetone tower reboiler are not less than 7 months; the continuous working days of the crude phenol tower reboiler are not less than 6.7 months; the continuous use days of the heavy component removal reboiler are about 3 days; the continuous working days of the heavy component removal tower are not less than 32 days; the daily output of phenol is stable at about 750 tons; the daily output of acetone is about 473 tons; the wastewater discharge is less than 8.5t / d; the tar amount is less than 2.11t / d. However, when the pH value of the neutralization tower continues to increase, the continuous working days of the crude acetone tower feed preheater, crude acetone tower reboiler, crude phenol tower reboiler, heavy component removal reboiler and heavy component removal tower will be significantly shortened; while the phenol and acetone outputs remain basically unchanged, the amount of wastewater and tar will increase significantly.
[0058] The pH value of the neutralizer was controlled between 5.0 and 5.8, the pH value of the neutralizer water washing tank was adjusted, and the online time of each distillation unit, phenol production, acetone production, wastewater volume and tar volume were tested. The test results are shown as follows:
[0059] Table 2
[0060]
[0061] Through the test data in Table 2, it is found that when the pH value of the neutralization water washing tank is controlled at 5.0-5.8, by adjusting the pH value of the neutralizer water washing tank, it can be found that when the pH value of the neutralizer is 6.5-7.0, the continuous working days of the crude acetone tower feed preheater, crude acetone tower reboiler, crude phenol tower reboiler, de-heavy component reboiler and de-heavy component tower are relatively stable and last for a long time; the phenol production and acetone production are also very stable, and the wastewater and tar are relatively small. However, when the pH value of the neutralizer water washing tank is greater than 7.0, the continuous working days of the crude acetone tower feed preheater, crude acetone tower reboiler, crude phenol tower reboiler, de-heavy component reboiler and de-heavy component tower will be significantly shortened; when the phenol production and acetone production are kept basically unchanged, the wastewater and tar will increase significantly.
[0062] Before the start of Examples 1 to 10, the online time of each distillation unit, phenol production, acetone production, wastewater volume and tar volume, and the test results are shown as follows:
[0063] Table 3
[0064]
[0065] From Table 1, Table 2 and Table 3, it can be seen that when the pH value of the neutralizer is controlled at 6.5-7.0 and the pH value of the neutralizer washing tank is controlled at 5.0-5.8, the amount of wastewater and tar becomes lower while ensuring that the product is of superior quality; the continuous online working time of the crude acetone tower reboiler and the crude phenol tower reboiler increases; the continuous online working time of the crude acetone tower feed preheater, the de-heavy component reboiler and the de-heavy component tower is relatively reduced. Since the crude acetone tower feed preheater, the de-heavy component reboiler and the de-heavy component tower are easy to switch and clean, the crude acetone tower reboiler and the crude phenol tower reboiler are difficult to switch and clean. Therefore, when the pH value of the neutralizer is controlled at 6.5-7.0 and the pH value of the neutralizer washing tank is controlled at 5.0-5.8, the production cost can be effectively reduced, thereby increasing the product revenue.
[0066] Among them, the best effect is achieved when the pH value of the neutralizer is controlled at 6.8-7.0 and the pH value of the neutralizer water washing tank is controlled at 5.6-5.8.
[0067] In summary, in the preparation method of phenol acetone provided by the present invention, by adjusting the pH value of the neutralization system, the output of wastewater can be effectively reduced during the production process, thereby reducing the salt accumulation phenomenon of the heat exchanger and further increasing the online operation time of each heat exchanger; the parameters of the heavy component tower can be further changed, thereby reducing the output of by-products such as tar and increasing the output of phenol and acetone. On the premise of ensuring that the product is a superior product, the production cost of the product is reduced and the market competitiveness of the product is improved.
[0068] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.
Claims
1. A method for preparing phenol acetone based on regulating the pH value of a neutralization system, characterized in that: The following steps are involved: S1 Oxidative decomposition: cumene and the recovered product from the concentration tower are introduced into the fixed bed reactor in the oxidation zone for oxidation reaction to generate cumene hydroperoxide. The cumene hydroperoxide is concentrated in the concentration tower and introduced into the decomposer for the first decomposition reaction to obtain a decomposition liquid. The decomposition liquid is pumped into the secondary decomposition reactor by the decomposition discharge pump to perform the next decomposition reaction to obtain a decomposition discharge. S2 Neutralization separation: The decomposed material obtained in step S1 is cooled in a neutralization feed cooler and then fed into a neutralization system, the pH value of the neutralization system is adjusted, and a neutralization reaction is performed; the organic phase of the neutralization tank and the salt solution circulating in the neutralization water washing tank are mixed in a static mixer and fed into the neutralization water washing tank; The sodium phenolate in the organic phase of the neutralization tank is extracted by the water phase of the neutralization water washing tank, the water phase is circulated by the neutralization water washing circulation pump, and the organic matter in the neutralization water washing tank overflows to the aggregator to remove the entrained water, thereby obtaining an acetone-phenol organic mixture; S3 product purification: the acetone-phenol organic mixture obtained in step S2 overflows into the distillation feed tank, and passes through the crude acetone tower and the refined acetone tower in sequence to obtain high-purity acetone; the kettle liquid coming out of the crude acetone tower enters the crude phenol tower, and then passes through the deweighting tower, the dehydrocarbon removal tower, the resin processor and the refined phenol tower in sequence to obtain high-purity phenol after separation.
2. A method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S1 oxidative decomposition step, the concentration of cumene hydroperoxide after concentration is in the range of 80-85%.
3. A method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S1 oxidation decomposition step, the catalyst used in the first decomposition reaction is concentrated sulfuric acid with a mass fraction of 98-99%.
4. A method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S2 neutralization and separation step, sodium phenolate and sodium hydroxide are used in the regulating neutralization system; wherein the mass ratio of sodium phenolate to sodium hydroxide is 1:(0.3-0.5).
5. A method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S2 neutralization and separation step, the pH value of the neutralization tank is controlled at 5.0 to 5.
8.
6. The method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S2 neutralization and separation step, the pH value of the neutralization water washing tank is controlled at 6.5 to 7.
0.
7. The method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S3 product purification step, there is a feed preheater in the crude acetone tower, and the feed preheater is heated by low-pressure steam, and the amount of low-pressure steam used is 11.73 to 11.94 t / h.
8. The method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S3 product purification step, a reboiler is provided at the bottom of the crude acetone tower. The reboiler contains high-pressure steam, and the amount of high-pressure steam used is 23.17 to 23.56 t / h.
9. The method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S3 product purification step, a reboiler is provided in the crude phenol tower, and the reboiler is heated by medium-pressure steam, and the amount of medium-pressure steam used is 9.71-9.80 t / h.
10. The method for preparing phenol acetone based on regulating the pH value of the neutralization system according to claim 1, characterized in that: In the S3 product purification step, a reboiler is provided in the deweighting tower, and the reboiler uses high-pressure steam, and the amount of high-pressure steam used is 3.05 to 3.13 t / h.