Process for treating phenol tar

Abstract

The application discloses a method for treating phenol tar, which comprises the following steps: performing a distillation reaction on a mixture containing phenol tar, dilution oil and a polymerization inhibitor in the presence of a solid acid catalyst, wherein the solid acid catalyst contains a solid carrier and an acid component loaded on the solid carrier. By means of the technical scheme, the phenol tar is subjected to the distillation reaction by using the solid acid catalyst, the yield of the distillation reaction product is significantly increased from 30% without adding the catalyst to more than 60%, and the solid acid catalyst is convenient to recycle and the performance of multiple uses is not obviously reduced.

Description

Technical Field

[0001] This invention relates to the field of phenol tar treatment technology, and more specifically to a method for treating phenol tar. Background Technology

[0002] Phenolic tar is a byproduct of the cumene process for producing phenol and acetone. It is classified as hazardous waste, generating an average of 100-200 kg of phenol tar for every ton of phenol produced. With the continuous increase in phenol production capacity, the amount of phenol tar produced has also increased significantly. In 2023, China's cumene process phenol production capacity exceeded 6 million tons. The approximate composition of phenol tar is as follows: cumene 0-10%, phenol 10-30%, acetophenone 5-30%, α-methylstyrene (α-MS) 0-10%, α-methylstyrene dimer (AMSD) 20-40%, cumylphenol 25-50%, and other components 5-20%. The traditional disposal method for phenol tar is combustion as fuel, but due to its high phenol and metal salt content, combustion is incomplete and causes environmental problems. Therefore, maximizing the recovery of useful components (such as phenol and acetophenone) from phenol tar, and cracking AMSD and cumylphenol into phenol and α-MS monomers, has both economic and environmental significance.

[0003] The main methods for obtaining high-value components from phenol tar include thermal cracking, hydrocracking, and catalytic cracking. Thermal cracking is simple to operate, but its reaction efficiency is low, and the yield of useful products is not high (usually not exceeding 40%). Hydrocracking consumes a large amount of H2 and converts high-value products such as α-MS and acetophenone into low-value products, making it uneconomical. Catalytic cracking involves adding a catalyst to phenol tar, causing AMSD and cumylphenol in the phenol tar to recombine and break down into components such as α-MS and phenol, which are then recovered along with acetophenone. Compared to thermal cracking, catalytic cracking can significantly reduce the reaction temperature and shorten the reaction time, while also achieving a higher yield of lighter components.

[0004] CN1154399A discloses a method for treating phenol tar, in which phosphoric acid, at a mass equivalent to 0.1-0.2% of the phenol tar, is added as a catalyst to the phenol tar, and the reaction is carried out in a column reactor at a temperature of 200-360ºC. The added phosphoric acid is dehydrated and polymerized to form non-volatile polyphosphoric acid. While the added phosphoric acid can catalyze the cracking of cumylphenol and AMSD, liquid phosphoric acid is highly corrosive to the equipment, and the catalyst cannot be separated from the residue, meaning trace amounts of catalyst may enter the product and affect its quality.

[0005] CN117865781A discloses a method and system for pyrolysis and recovery of phenol tar. The method includes: preheating phenol tar with an organic silver salt catalyst and then carrying out a pyrolysis reaction to obtain light components and heavy components. However, the method has the problems of high catalyst cost and the presence of metallic silver residue in the pyrolysis residue, which affects its further utilization. Summary of the Invention

[0006] The main technical problem addressed by this invention is how to effectively improve the product yield of phenol tar recovery.

[0007] To achieve the above objectives, the present invention provides a method for treating phenol tar, comprising: a step of distilling a mixture containing phenol tar, diluent oil and polymerization inhibitor in the presence of a solid acid catalyst, wherein the solid acid catalyst contains a solid support and an acid component supported on the solid support.

[0008] In some embodiments, the solid acid catalyst is obtained by calcining the solid support with an acid.

[0009] In some embodiments, the solid support is one or more of Al2O3, SiO2, TiO2, CeO2, ZrO2, and activated carbon.

[0010] In some embodiments, the acid is one or more selected from phosphoric acid, sulfuric acid, perchloric acid, hydrochloric acid, and nitric acid.

[0011] In some embodiments, the solid carrier is in the shape of one or more of the following: cylindrical, clover-shaped, four-leaf clover-shaped, spherical, and toothed spherical, preferably four-leaf clover-shaped.

[0012] In some embodiments, the calcination conditions include a temperature of 400-600°C and a time of 2-8 hours.

[0013] In some embodiments, the amount of the solid acid catalyst is 0.1-3% of the mass of the phenol tar.

[0014] In some embodiments, the amount of the polymerization inhibitor is 100-1000 ppm of the mass of the phenol tar, preferably 150-800 ppm, and more preferably 200-500 ppm.

[0015] In some embodiments, the polymerization inhibitor is one or more of 2-sec-butyl-4,6-dinitrophenol and p-tert-butylcatechol, preferably 2-sec-butyl-4,6-dinitrophenol.

[0016] In some embodiments, the amount of the diluent oil is 2-10% of the mass of the phenol tar, preferably 2-5%.

[0017] In some embodiments, the diluent oil is an oil with a boiling point of 320°C or higher, preferably one or more of industrial white oil, heavy diesel oil, and liquid paraffin.

[0018] In some embodiments, the distillation reaction step preferably includes: mixing the phenol tar, the diluent oil, and the polymerization inhibitor in the presence of the solid acid catalyst, then heating to the reaction temperature to carry out a cracking reaction, obtaining cracking products, and distilling off the light components in the phenol tar; Preferably, the reaction temperature is 220-350℃; More preferably, the reaction temperature is 260-320°C; Most preferably, the reaction temperature is 300°C.

[0019] In some embodiments, the method further includes a step of recovering the catalyst by solid-liquid separation of the residue from the distillation reaction; Preferably, the recovered catalyst is used as at least a portion of the solid acid catalyst.

[0020] Through the above technical solution, the present invention uses a solid acid catalyst to distill phenol tar, wherein the yield of the distillation reaction product is significantly increased from 30% without the addition of the catalyst to more than 60%.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The well-formed solid acid catalyst used in this invention is easy to separate from the distillation reaction residue, realizing the recycling of the catalyst. It also overcomes the disadvantages of the prior art where metal ions remain in the distillation reaction residue when metal sulfates or alkaline metal oxides are used as catalysts, making it difficult to burn the residue and reuse it.

[0022] (2) The solid acid catalyst selected in this invention contains less free H compared to traditional strong acids (such as concentrated sulfuric acid, concentrated nitric acid, etc.). + It has low corrosiveness to equipment and good safety.

[0023] (3) The diluent oil selected in this invention can significantly reduce the pour point of the liquid material remaining after the phenol tar distillation reaction, which facilitates discharge and separation from the recovered catalyst, reduces the risk of blockage of equipment pipelines, and facilitates the secondary utilization of the residual material after the distillation reaction.

[0024] (4) By adding a polymerization inhibitor, the present invention can significantly inhibit the secondary polymerization of monomers such as α-MS and phenol, thereby increasing the yield and proportion of distillation reaction products. Detailed Implementation

[0025] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] To address the problem of low material recovery rate in phenol tar in existing technologies, this invention provides a method for treating phenol tar. The method includes: a step of distilling a mixture containing phenol tar, diluent oil, and polymerization inhibitor in the presence of a solid acid catalyst, wherein the solid acid catalyst contains a solid support and an acid component supported on the solid support.

[0028] Distillation reaction refers to the process of distilling and catalytic cracking of the mixture. The product of distillation reaction is the light component after the cracking of phenol tar. The residual material of distillation reaction includes solid material (catalyst to be recovered) and liquid material.

[0029] The main technical principle of this invention is as follows: during the phenol tar distillation reaction, AMSD is decomposed into α-MS, and cumylphenol is decomposed into α-MS and phenol.

[0030] The phenol tar involved in the distillation reaction is a byproduct of the cumene process for producing phenol and acetone. Its components, by mass, include: cumene, 0-10%; phenol, 10-30%; acetophenone, 5-30%; α-MS, 0-10%; α-methylstyrene dimer (AMSD), 20-40%; cumylphenol, 25-50%; and other components, 5-20%.

[0031] The preferred steps of the above distillation reaction include: mixing phenol tar, diluent oil and polymerization inhibitor in the presence of a solid acid catalyst, heating to the reaction temperature to carry out a cracking reaction, obtaining cracking products, and distilling off the light components in the phenol tar.

[0032] According to the present invention, the light component contains cumene, α-MS, phenol and acetophenone, preferably, the light component is cumene, α-MS, phenol and acetophenone.

[0033] According to the present invention, the reaction temperature is preferably 220-350°C, more preferably 260-320°C, and most preferably 300°C.

[0034] According to the present invention, the distillation and pyrolysis reactions in the distillation reaction step can be carried out simultaneously. The purpose of the reaction at the reaction temperature is to pyrolyze cumylphenol and AMSD into phenol and α-MS. The purpose of the distillation at the reaction temperature is to remove light components (such as cumene, α-MS, phenol, and acetophenone). The distillation reaction time at the reaction temperature is set such that the light components in the phenol tar are substantially removed (preferably completely removed).

[0035] In this invention, "basically removed" means removing 90% or more of the mass of the light component, preferably 95% or more, and more preferably 98% or more.

[0036] According to the present invention, preferably, the above-mentioned distillation reaction further includes a preheating step: adding phenol tar to a reaction vessel and heating it to a first temperature and maintaining it for a period of time to remove a small amount of water from the phenol tar. The first temperature can be 80-150°C, preferably 140°C.

[0037] According to the present invention, preferably, the above-mentioned distillation reaction further includes: cooling the distilled light component to a second temperature and collecting it after the distillation reaction is completed. Here, cooling means cooling the distilled light component to a liquid state in a cooler, and the second temperature is preferably 10-40°C.

[0038] In some embodiments, the solid acid catalyst is obtained by calcining a solid support with an acid.

[0039] According to the present invention, the calcination step includes: firstly, adding liquid acid to a solid carrier and stirring, then drying the stirred mixture, and then calcining it.

[0040] The drying temperature is set to 80-150℃, preferably 120℃; the drying time is set to 8-20 hours, preferably 12 hours.

[0041] The roasting temperature is set to 400-600℃, preferably 450℃; the roasting time is set to 2-8 hours, preferably 4 hours.

[0042] In some embodiments, the solid support is one or more of Al2O3, SiO2, TiO2, CeO2, ZrO2 and activated carbon.

[0043] In some embodiments, the acid is one or more of phosphoric acid, sulfuric acid, perchloric acid, hydrochloric acid, and nitric acid.

[0044] In some embodiments, the solid carrier is in one or more of the following shapes: cylindrical, clover-shaped, four-leaf clover-shaped, spherical, and toothed spherical, preferably four-leaf clover-shaped.

[0045] According to the present invention, a well-formed solid acid catalyst can be prepared using the solid support of the above-described shape to achieve solid-liquid separation of distillation reaction residues, solving the problem that existing powdered catalysts cannot be separated from the liquid residues of distillation reactions. In some specific embodiments, the solid-liquid separation of the distillation reaction residues is achieved by using a sieve, with the sieve mesh size set to 10-200 mesh, preferably 20-60 mesh. Experiments have shown that using the solid acid catalyst of the present invention, the catalyst recovery rate after solid-liquid separation of distillation reaction residues is ≥95%.

[0046] In some embodiments, the maximum diameter of the interface of the solid carrier can be 0.5-5 mm, preferably 1.0-1.5 mm; the length can be 2-10 mm, preferably 3-8 mm.

[0047] In some embodiments, the amount of solid acid catalyst used is 0.1-3% of the mass of phenol tar.

[0048] In some embodiments, the amount of polymerization inhibitor used is 100-1000 ppm by weight of phenol tar, preferably 150-800 ppm, and more preferably 200-500 ppm.

[0049] In some embodiments, the polymerization inhibitor is one or more of 2-sec-butyl-4,6-dinitrophenol and p-tert-butylcatechol, preferably 2-sec-butyl-4,6-dinitrophenol.

[0050] In some embodiments, the amount of diluent oil used is 2-10% of the mass of phenol tar, preferably 2-5%.

[0051] In some embodiments, the diluent oil is an oil with a boiling point of 320°C or higher, preferably one or more of industrial white oil, heavy diesel oil, and liquid paraffin.

[0052] The preferred diluent is industrial white oil.

[0053] In some embodiments, the method further includes a step of recovering the catalyst by solid-liquid separation of the residue from the distillation reaction; Preferably, the recovered catalyst is used as at least a portion of the solid acid catalyst.

[0054] The catalyst in the residual material of the distillation reaction can be recovered multiple times and used as at least a part of the solid acid catalyst, preferably 1-3 times.

[0055] According to the present invention, preferably, the above-mentioned catalyst recovery step further includes a cleaning and drying step. The cleaning solvent can be one of acetone and N,N-dimethylformamide, preferably acetone; the drying time can be 2-12 hours; and the drying temperature can be 80-180°C.

[0056] Example 1 The phenol tar was preheated to 140°C.

[0057] Add 1.0% by weight of phenol tar, 5.0% by weight of solid acid catalyst H3PO4 / SiO2, 500 ppm by weight of diluent oil, and 500 ppm of polymerization inhibitor, and then heat to 300°C for 4 hours for distillation reaction.

[0058] The solid acid catalyst was recovered 0 times.

[0059] The results showed that the product yield of the distillation reaction was 71.0%, the total conversion rate of AMSD and cumylphenol was 67.6%, and the pour point of the liquid residue from the distillation reaction was 51℃.

[0060] Example 2 The procedure was carried out according to Example 1, except that the solid acid catalyst used was H3PO4 / Al2O3.

[0061] The results showed that the product yield of the distillation reaction was 65.2%, the total conversion rate of AMSD and cumylphenol was 57.6%, and the pour point of the liquid residue from the distillation reaction was 50℃.

[0062] Example 3 The procedure was carried out according to the method of Example 1, except that the solid acid catalyst used was H3PO4 / TiO2.

[0063] The results showed that the product yield of the distillation reaction was 64.7%, the total conversion rate of AMSD and cumylphenol was 56.7%, and the pour point of the liquid residue from the distillation reaction was 51℃.

[0064] Example 4 The method was carried out according to Example 1, except that the reaction temperature was 270°C.

[0065] The results showed that the product yield of the distillation reaction was 60.9%, the total conversion rate of AMSD and cumylphenol was 50.2%, and the pour point of the liquid residue from the distillation reaction was 49℃.

[0066] Example 5 The method was carried out according to Example 1, except that the amount of solid acid catalyst used was 0.3% of the mass of phenol tar.

[0067] The results showed that the product yield of the distillation reaction was 63.4%, the total conversion rate of AMSD and cumylphenol was 54.5%, and the pour point of the liquid residue from the distillation reaction was 50℃.

[0068] Example 6 The method was carried out according to Example 1, except that the amount of diluent oil used was 2% of the mass of phenol tar.

[0069] The results showed that the product yield of the distillation reaction was 69.5%, the total conversion rate of AMSD and cumylphenol was 65.0%, and the pour point of the liquid residue from the distillation reaction was 68℃.

[0070] Example 7 The method was carried out according to Example 1, except that the amount of polymerization inhibitor used was 200 ppm of the phenol tar mass.

[0071] The results showed that the product yield of the distillation reaction was 66.1%, the total conversion rate of AMSD and cumylphenol was 59.1%, and the pour point of the liquid residue from the distillation reaction was 49℃.

[0072] Example 8 The procedure was carried out according to Example 1, except that the solid acid catalyst was recovered once.

[0073] The results showed that the product yield of the distillation reaction was 70.1%, the total conversion rate of AMSD and cumylphenol was 66.0%, and the pour point of the liquid residue from the distillation reaction was 51℃.

[0074] Example 9 The procedure was carried out according to Example 1, except that the solid acid catalyst was recovered twice.

[0075] The results showed that the product yield of the distillation reaction was 69.9%, the total conversion rate of AMSD and cumylphenol was 65.7%, and the pour point of the liquid residue from the distillation reaction was 50℃.

[0076] Example 10 The procedure was carried out according to Example 1, except that the solid acid catalyst was recovered three times.

[0077] The results showed that the product yield of the distillation reaction was 69.5%, the total conversion rate of AMSD and cumylphenol was 65.0%, and the pour point of the liquid residue from the distillation reaction was 51℃.

[0078] Comparative Example 1 The method of Example 1 was followed, except that no polymerization inhibitor was added.

[0079] The results showed that the product yield of the distillation reaction was 61.9%, the total conversion rate of AMSD and cumylphenol was 51.9%, and the pour point of the liquid residue from the distillation reaction was 49℃.

[0080] Comparative Example 2 The procedure was carried out according to Example 1, except that no diluent oil was added.

[0081] The results showed that the product yield of the distillation reaction was 68.9%, the total conversion rate of AMSD and cumylphenol was 64.0%, and the pour point of the liquid residue from the distillation reaction was 101℃.

[0082] Comparative Example 3 The method was carried out according to Example 1, except that no solid acid catalyst, diluent oil, and polymerization inhibitor were added.

[0083] The results showed that the product yield of the distillation reaction was 33.3%, the total conversion rate of AMSD and cumylphenol was 2.6%, and the pour point of the liquid residue from the distillation reaction was 47℃.

[0084] Table 1

[0085] The results of Examples 1-7 show that by using a solid acid catalyst and adding a certain amount of polymerization inhibitor and diluent oil, a distillation reaction product yield of 60%-71% can be obtained, and the total conversion rate of AMSD and cumylphenol can reach up to 67.6%. Moreover, the pour point of the liquid material remaining after distillation reaction is low, at 49-68°C.

[0086] The results of Examples 8-10 show that the solid acid catalyst has good stability and its performance remains basically unchanged after being recycled three times.

[0087] The results of Comparative Example 1 show that without the addition of a polymerization inhibitor, the yield of the distillation reaction product is significantly reduced.

[0088] The results of Comparative Example 2 show that without the addition of diluent oil, the pour point of the liquid material remaining after the distillation reaction rises to 101°C, which significantly increases the difficulty of handling the remaining material during solid-liquid separation.

[0089] The results of Comparative Example 3 show that without the addition of solid acid catalyst, diluent oil and polymerization inhibitor, the yield of distillation reaction products is significantly reduced.

[0090] The results above show that by using the solid acid catalyst of the present invention, the yield of distillation reaction products and the total conversion rate of AMSD and cumylphenol can be significantly improved; at the same time, the polymerization inhibitor can slow down the secondary polymerization of phenol and α-MS during the reaction, further improving the yield of distillation reaction products; the use of diluent oil can significantly reduce the pour point of the liquid material remaining in the distillation reaction, facilitating discharge and solid-liquid separation of the remaining material; the selected solid acid catalyst has good stability, is easy to recover, and its performance does not decline significantly after being reused three times.

[0091] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method of treating phenolic tar, characterized by, The method includes the step of distilling a mixture containing phenol tar, diluent oil and polymerization inhibitor in the presence of a solid acid catalyst, wherein the solid acid catalyst contains a solid support and an acid component supported on the solid support.

2. The method of claim 1, wherein, The solid acid catalyst is obtained by calcining the solid support with acid.

3. The method of claim 2, wherein, The solid support is one or more of Al2O3, SiO2, TiO2, CeO2, ZrO2 and activated carbon.

4. The method of claim 2, wherein, The acid is one or more of phosphoric acid, sulfuric acid, perchloric acid, hydrochloric acid, and nitric acid.

5. The method of claim 2, wherein, The solid carrier is one or more of the following shapes: cylindrical, clover-shaped, four-leaf clover-shaped, spherical, and toothed spherical, preferably four-leaf clover-shaped.

6. The method of claim 2, wherein, The roasting conditions include a temperature of 400-600℃ and a time of 2-8 hours.

7. The method of any of claims 1-6, wherein, The amount of the solid acid catalyst used is 0.1-3% of the mass of the phenol tar.

8. The method of any of claims 1-6, wherein, The amount of the polymerization inhibitor is 100-1000 ppm of the mass of the phenol tar, preferably 150-800 ppm, and more preferably 200-500 ppm.

9. The method of any of claims 1-6, wherein, The polymerization inhibitor is one or more of 2-sec-butyl-4,6-dinitrophenol and p-tert-butylcatechol, preferably 2-sec-butyl-4,6-dinitrophenol.

10. The method of any of claims 1-6, wherein, The amount of the diluent oil used is 2-10% of the mass of the phenol tar, preferably 2-5%.

11. The method of any one of claims 1-6, wherein, The diluent oil is an oil with a boiling point of 320°C or higher, preferably one or more of industrial white oil, heavy diesel oil, and liquid paraffin.

12. The method according to any one of claims 1-6, wherein, The distillation reaction step preferably includes: mixing the phenol tar, the diluent oil and the polymerization inhibitor in the presence of the solid acid catalyst, heating to the reaction temperature to carry out a cracking reaction, obtaining cracking products and distilling off the light components in the phenol tar; Preferably, the reaction temperature is 220-350℃; More preferably, the reaction temperature is 260-320°C; Most preferably, the reaction temperature is 300°C.

13. The method according to any one of claims 1-6, wherein, The method also includes the step of performing solid-liquid separation to recover the catalyst from the residue of the distillation reaction; Preferably, the recovered catalyst is used as at least a portion of the solid acid catalyst.

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