Preparation method of high-purity acetone

Abstract

The invention relates to the technical field of preparation of high-purity chemical reagents, in particular to a preparation method of high-purity acetone. The preparation method comprises the following steps: S1, in the presence of an oxidation reactant aqueous solution, carrying out first impurity removal treatment on an acetone crude product to obtain a first product material; and S2, in the presence of an alkali metal hydroxide solution, performing secondary impurity removal treatment on the first product material, and then performing post-treatment to obtain the high-purity acetone. The high-purity acetone prepared by the preparation method disclosed by the invention is high in purity, low in aldehydes and acid value, and capable of meeting the requirements of IC (Integrated Circuit) manufacturing on the purity of acetone, and meanwhile, the preparation method also has high acetone recovery rate.

Description

Technical Field

[0001] The invention relates to the technical field of high-purity chemical reagent preparation, and in particular to a method for preparing high-purity acetone. Background Art

[0002] Acetone is an important organic solvent. It is liquid at room temperature, colorless and transparent, easily soluble in water and a variety of organic solvents, has active chemical properties, and is an important raw material for synthesizing chemicals such as ketene, acetic anhydride, iodoform, and epoxy resin.

[0003] High-purity acetone is one of the key basic raw materials in the manufacturing process of large-scale integrated circuits. The purity of commercially available industrial-grade acetone is as high as 99.5%, which contains a small amount of organic impurities such as unsaturated hydrocarbons and water, making the product unable to meet the requirements of acetone purity for IC manufacturing. Therefore, it is of great significance to further purify acetone to meet the needs of IC manufacturing and the requirements of food and pesticide residue analysis.

[0004] There are few reports on the preparation process of high-purity acetone, and most of them focus on the recovery of acetone waste solvent. The few articles that exist all have certain process defects, such as the document "Study on the Preparation Process of High-Purity Acetone", which reports the use of two-stage sub-boiling distillation to obtain high-purity acetone. However, the process has a small processing flux and cannot meet the needs of industrial production. There is also a document such as "Study on the Preparation Method of High-Purity Acetone", which adopts the adsorption-drying-distillation process route to obtain high-purity acetone. The above-mentioned product has a high moisture content, and the acetone purity only reaches 99.9%. There is also a document such as "Study on the Purification Method of High-Purity Reagent Acetone", which only adopts the drying-filtration-distillation method to obtain high-purity acetone. This method has a general removal effect on organic impurities, especially unsaturated organic impurities, which affects the purity of the product acetone.

[0005] Therefore, it is very urgent to develop a method for preparing high-purity acetone, especially an acetone product with high product purity and low aldehyde and acid value. Summary of the invention

[0006] The object of the present invention is to provide a novel method for preparing high-purity acetone. The high-purity acetone product obtained by the preparation method has high purity and low aldehydes and acid values.

[0007] The invention provides a novel method for preparing high-purity acetone, which comprises: S1, in the presence of an aqueous solution of an oxidizing reactant, performing a first impurity removal treatment on a crude acetone product to obtain a first product material; S2, in the presence of an alkali metal hydroxide solution, performing a second impurity removal treatment on the first product material, and then performing post-treatment to obtain high-purity acetone.

[0008] Through the above technical scheme, the high-purity acetone prepared by the preparation method of the present invention has high purity, low aldehydes and acid values, and can meet the requirements of IC manufacturing on acetone purity. At the same time, the preparation method also has a high acetone recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The figure is a schematic flow diagram of a method for preparing high-purity acetone in one embodiment of the present invention.

[0010] Description of Reference Numerals

[0011] 1. Acetone crude product 2. Oxidation reagent aqueous solution 3. First product material

[0012] 4. Alkali metal hydroxide solution 5. Second product material 6. Third material

[0013] 7. Light components 8. Bottom products 9. Acetone products

[0014] 10. Heavy component ①, first stirred tank ②, second stirred tank

[0015] ③Adsorption dehydration device④, first distillation tower⑤, second distillation tower DETAILED DESCRIPTION

[0016] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0017] The "purity" in the present invention is measured by mass percentage.

[0018] The present invention provides a novel method for preparing high-purity acetone, which comprises:

[0019] S1, in the presence of an aqueous solution of an oxidizing agent, performing a first impurity removal treatment on the crude acetone product to obtain a first product material;

[0020] S2: In the presence of an alkali metal hydroxide solution, the first product material is subjected to a second impurity removal treatment, and then subjected to post-treatment to obtain high-purity acetone.

[0021] In the present invention, the crude acetone is firstly subjected to impurity treatment in the presence of an oxidizing agent aqueous solution, and then subjected to secondary impurity removal treatment using an alkali metal hydroxide solution, and finally subjected to post-treatment to prepare high-purity acetone with a purity greater than 99.99%. Furthermore, after the crude acetone undergoes multiple-step treatment, a high acetone recovery rate can be maintained.

[0022] According to the present invention, the oxidizing agent aqueous solution refers to an aqueous solution containing an oxidizing agent. As long as the purpose of the present invention can be achieved, the type of the oxidizing agent is not particularly limited. In some preferred embodiments, the oxidizing agent aqueous solution includes an acidic oxidant and water. The above embodiment can increase the purity of the acetone product finally prepared.

[0023] According to the present invention, in some preferred embodiments, the acidic oxidant includes at least one of potassium permanganate, sodium dichromate, hydrogen peroxide and potassium perchlorate.

[0024] According to the present invention, in some more preferred embodiments, the acidic oxidant is potassium permanganate and / or hydrogen peroxide.

[0025] According to the present invention, in some more preferred embodiments, the acidic oxidant is The acidic oxidant is. By adopting the above-mentioned embodiment, the purity of the acetone product finally prepared can be better increased.

[0026] According to the present invention, in some preferred embodiments, the aqueous solution of the oxidizing agent further comprises a stabilizer. The above-mentioned embodiment can better promote the stable removal of impurities of the acidic oxidant and reduce the acid value of the acetone product finally prepared.

[0027] According to the present invention, in some preferred embodiments, the stabilizer is selected from at least one of polyphosphate, poly(alkyl)acrylate, gluconate and metasilicate. The above embodiment can better promote the stable removal of impurities of the acidic oxidant and reduce the acid value of the acetone product finally prepared.

[0028] According to the present invention, the polyphosphate that can be cited is sodium pyrophosphate, the poly(alkyl)acrylate that can be cited is sodium polyacrylate, the gluconate that can be cited is sodium gluconate, and the metasilicate that can be cited is sodium metasilicate.

[0029] According to the present invention, in some preferred embodiments, the stabilizer is at least one of sodium pyrophosphate, sodium polyacrylate and sodium metasilicate. The above embodiments can not only increase the purity of the acetone product, reduce the acid value of the acetone product, but also increase the recovery rate of acetone.

[0030] According to the present invention, in some more preferred embodiments, the stabilizer is sodium pyrophosphate. The above embodiments can better increase the recovery rate of acetone.

[0031] According to the present invention, in some embodiments, in the alkali metal hydroxide solution, the alkali metal hydroxide is selected from at least one of lithium hydroxide, sodium hydroxide and potassium hydroxide.

[0032] According to the present invention, in some preferred embodiments, the content of the acidic oxidant in the aqueous solution of the oxidizing agent is 0.1-20wt%, for example, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 4wt%, 5wt%, 10wt%, 15wt%, 20wt%, or a range consisting of any two of the above values. The above embodiment can better increase the purity of the acetone product finally prepared.

[0033] According to the present invention, in some preferred embodiments, the content of the acidic oxidant in the aqueous solution of the oxidizing agent is 1-10wt%, preferably 1-5wt%. The above embodiment can better increase the purity of the acetone product finally prepared.

[0034] According to the present invention, in some preferred embodiments, the content of the stabilizer in the aqueous solution of the oxidizing agent is 0.1-20wt%, for example, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 4wt%, 5wt%, 10wt%, 15wt%, 20wt%, or a range consisting of any two of the above values. The above embodiment can better increase the purity of the acetone product finally prepared.

[0035] According to the present invention, in some preferred embodiments, the content of the stabilizer in the aqueous solution of the oxidation reactant is 2-5wt%. The above embodiment can better increase the purity of the final prepared acetone product and increase the recovery rate of the final acetone product.

[0036] According to the present invention, it can be understood that the alkali metal hydroxide solution refers to a solution formed by dissolving an alkali metal hydroxide in a good solvent. As long as the purpose of the present invention can be achieved, the type of the good solvent is not particularly limited, and water is preferred.

[0037] According to the present invention, in some preferred embodiments, the molar concentration of the alkali metal hydroxide in the alkali metal hydroxide solution is 0.5-5 mol / L, for example, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, or a range consisting of any two of the above values. The above embodiment can better increase the purity of the acetone product finally prepared and reduce the acid value of the acetone product.

[0038] According to the present invention, in some embodiments, the mass of the aqueous solution of the oxidizing agent is 0.1-1wt% of the mass of the crude acetone, for example, 0.1wt%, 0.3wt%, 0.5wt%, 0.7wt%, 1wt%, or a range consisting of any two of the above values. The above embodiment can better increase the purity of the acetone product finally prepared and control the water content in the acetone product.

[0039] According to the present invention, in some embodiments, the mass of the alkali metal hydroxide solution is 0.1-1wt% of the mass of the crude acetone, for example, 0.1wt%, 0.3wt%, 0.5wt%, 0.7wt%, 1wt%, or a range consisting of any two of the above values. The above embodiment can better increase the purity of the acetone product finally prepared and control the water content in the acetone product.

[0040] According to the present invention, in some embodiments, the content of acetone in the crude acetone is 98.5-99.9 wt %.

[0041] According to the present invention, crude acetone refers to an acetone product containing some impurities, wherein these impurities are generally water, alcohol impurities, olefin impurities, ether impurities and ketone impurities. In some embodiments, the crude acetone also contains at least one of water, isopropanol, acetaldehyde, propionaldehyde, propylene, isopropyl ether, methanol and 4-hydroxy-4-methyl-2-pentanone. The method of the present invention can better reduce the content of the aforementioned impurities that may exist and increase the purity of the acetone product.

[0042] According to the present invention, as long as the purpose of the present invention can be achieved, the conditions of the first impurity removal treatment are not particularly limited. In some embodiments, the conditions of the first impurity removal treatment include: a temperature of 15-50°C, for example, 15°C, 20°C, 30°C, 35°C, 40°C, 50°C, or a range consisting of any two of the above values. The above embodiment can better increase the purity of the acetone product finally prepared and reduce the content of total aldehyde impurities in the acetone product.

[0043] According to the present invention, in some preferred embodiments, the conditions of the first impurity removal treatment include: a temperature of 35-50° C. The above embodiment can better increase the purity of the acetone product finally prepared and reduce the content of total aldehyde impurities in the acetone product.

[0044] According to the present invention, as long as the purpose of the present invention can be achieved, the conditions of the first impurity removal treatment are not particularly limited. In some embodiments, the conditions of the first impurity removal treatment include: a time of 2-5 hours.

[0045] According to the present invention, as long as the purpose of the present invention can be achieved, the conditions of the second impurity removal treatment are not particularly limited. In some embodiments, the conditions of the second impurity removal treatment include: a temperature of 15-50°C, for example, 15°C, 20°C, 30°C, 35°C, 40°C, 50°C, or a range consisting of any two of the above values. The above embodiment can better increase the purity of the acetone product finally prepared and reduce the acid value of the acetone product.

[0046] According to the present invention, as long as the purpose of the present invention can be achieved, the conditions of the second impurity removal treatment are not particularly limited. In some embodiments, the conditions of the second impurity removal treatment include: a temperature of 15-40° C. The above embodiment can better increase the purity of the acetone product finally prepared and reduce the acid value of the acetone product.

[0047] According to the present invention, as long as the purpose of the present invention can be achieved, the conditions of the second impurity removal treatment are not particularly limited. In some embodiments, the conditions of the second impurity removal treatment include: a time of 0.5-2h.

[0048] The equipment for the first impurity removal and the second impurity removal in the present invention can be conventional equipment in the art, such as a stirred tank.

[0049] According to the present invention, as long as the purpose of the present invention can be achieved, the post-treatment method is not particularly limited, preferably, the post-treatment includes dehydration, filtration, light removal, and heavy removal. The above-mentioned embodiment can better increase the purity of the acetone product finally prepared.

[0050] According to the present invention, as long as the purpose of the present invention can be achieved, the dehydration method is not particularly limited. In some embodiments, the dehydration method includes adsorption separation dehydration. The above embodiment can better reduce the water content in the acetone product.

[0051] The adsorption separation and dehydration in the present invention refers to the use of an adsorbent to adsorb water in a material. In some preferred embodiments, the adsorbent in the adsorption separation and dehydration includes a molecular sieve and / or an inorganic salt desiccant.

[0052] According to the present invention, in some preferred embodiments, the combination of the adsorbent molecular sieve and the inorganic salt desiccant in the adsorption separation dehydration. The above-mentioned embodiment can better reduce the water originally contained in the adsorbed acetone crude product and the water that may be brought by the steps before dehydration, reduce the water content in the acetone product, and better reduce the acid value in the acetone product.

[0053] According to the present invention, in some preferred embodiments, the molecular sieve is at least one of type 3A molecular sieve, type 4A molecular sieve and type 5A molecular sieve, preferably type 5A molecular sieve.

[0054] According to the present invention, in some preferred embodiments, the inorganic salt desiccant is selected from at least one of calcium chloride, soda lime, quicklime and sodium hydroxide solid, preferably calcium chloride.

[0055] According to the present invention, in some preferred embodiments, the method of adsorption separation dehydration comprises: at room temperature, the second product material is contacted with an inorganic salt desiccant and a molecular sieve in sequence. The aforementioned contacting method can be a conventional method in the art, for example, an inorganic salt desiccant and a molecular sieve are sequentially loaded into an adsorption dehydration device, and the second product material enters the adsorption dehydration device for dehydration.

[0056] According to the present invention, the light removal treatment is mainly for removing impurities with a boiling point lower than that of the acetone product. As long as the purpose of the present invention can be achieved, the conditions of the light removal treatment are not particularly limited. In some preferred embodiments, the light removal conditions include: an operating pressure of 100-200 kPa (absolute pressure).

[0057] The light removal and heavy removal in the present invention can be carried out in a conventional distillation tower in the art.

[0058] According to the present invention, in some preferred embodiments, the conditions for removing light include: a reflux ratio of 2-20, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, or a range consisting of any two of the above values. The purity of the acetone product finally prepared can be better increased.

[0059] According to the present invention, in some preferred embodiments, the light removal condition includes: a reflux ratio of 8 to 15. The above embodiment can better increase the purity of the acetone product finally prepared and increase the recovery rate of the acetone product.

[0060] According to the present invention, in some preferred embodiments, the conditions for removing light substances include: the bottom temperature of the tower is 56.6°C-78.0°C.

[0061] According to the present invention, the de-weighting treatment is mainly for removing impurities with a boiling point higher than that of the acetone product. As long as the purpose of the present invention can be achieved, the conditions of the de-weighting treatment are not particularly limited. In some preferred embodiments, the de-weighting conditions include: an operating pressure of 100-200 kPa (absolute pressure).

[0062] According to the present invention, in some preferred embodiments, the weight removal conditions include: a reflux ratio of 0.2-5, for example, 0.2, 1, 2, 3, 4, 5, or a range consisting of any two of the above values.

[0063] According to the present invention, in some preferred embodiments, the weight removal conditions include: the tower top temperature is 55.7-77.5°C.

[0064] According to the present invention, Figure 1 As shown, in some embodiments, the preparation method of high-purity acetone includes: injecting an industrial-grade acetone crude product 1 into a first stirring tank ①, and adding an oxidizing reactant aqueous solution 2 (the solvent is water) to perform a first impurity removal treatment to obtain a first product material 3; injecting the first product material 3 into a second stirring tank ②, and adding an alkali metal hydroxide solution 4 to perform a second impurity removal treatment; injecting a second product material 5 obtained by the second impurity removal treatment into an adsorption dehydration device ③, the adsorption dehydration device is filled with an adsorbent, and injecting a third material 6 from the dehydration device ③ into a first distillation tower ④ for light removal; removing light components 7 from the top of the first distillation tower ④, and injecting a bottom product 8 of the first distillation tower ④ into a second distillation tower ⑤ for heavy removal, the operating pressure (absolute pressure) of the heavy removal is 125 kPa, the reflux ratio is 2, and the top temperature is controlled to be 62.4°C, and finally obtaining a high-purity acetone product 9 at the top of the second distillation tower ⑤, and the bottom of the second distillation tower ⑤ is a heavy component 10.

[0065] The present invention will be described in detail below through examples. In the following examples, the purity of the products was tested by HPLC, the water content was determined by Karl Fischer titrator, and the acid value was determined by acid-base titrator.

[0066] Example 1

[0067] like Figure 1 As shown, a batch of industrial-grade acetone crude product 1 is put into a first stirred tank ①, wherein the acetone crude product 1 has a purity of 99.5%, a water content of 2500ppm, and a total aldehyde content of 56ppm. At the same time, 0.005 times (based on the mass of the industrial-grade acetone crude product 1) of an oxidizing agent aqueous solution 2 (the solvent is water) containing 5wt% potassium permanganate and 5wt% sodium pyrophosphate is added, and the mixture is stirred at 40°C for 4h to perform a first impurity removal treatment to obtain a first product material;

[0068] The first product material 3 is put into the second stirred tank ②, and 0.005 times (based on the mass of the industrial grade acetone crude product 1) of 3 mol / L sodium hydroxide alkali metal hydroxide solution 4 is added and stirred at 25°C for 1 hour for the second impurity removal treatment.

[0069] The second product material 5 obtained by the second impurity removal treatment is pumped into the adsorption dehydration device ③, which is sequentially filled with inorganic desiccant calcium chloride and 5A molecular sieve, and the third material 6 from the dehydration device ③ is pumped into the first distillation tower ④ for light removal, and the operating pressure (absolute pressure) of light removal is 110 kPa, the reflux ratio is 10, and the tower bottom temperature is controlled to be 59.0°C;

[0070] The light component 7 is removed from the top of the first distillation tower ④, and the bottom product 8 of the first distillation tower ④ is pumped into the second distillation tower ⑤ for heavy removal. The operating pressure (absolute pressure) of heavy removal is 125 kPa, the reflux ratio is 2, and the top temperature is controlled to be 62.4°C. Finally, a high-purity acetone product 9 is obtained at the top of the second distillation tower ⑤, and the bottom of the second distillation tower ⑤ is the heavy component 10.

[0071] Example 2

[0072] The method of Example 1 is followed, except that the aqueous solution of the oxidizing agent contains 2 wt % potassium permanganate and 5 wt % sodium pyrophosphate; the rest is the same as Example 1, and a high-purity acetone product is finally obtained.

[0073] Example 3

[0074] The method of Example 1 is followed, except that the operating reflux ratio of the second distillation is 5; the rest is the same as Example 1, and a high-purity acetone product is finally obtained.

[0075] Example 4

[0076] The method of Example 1 is followed, except that the first impurity removal treatment is performed under stirring at 5° C. for 4 h; the rest is the same as in Example 1, and finally a high-purity acetone product is obtained.

[0077] Example 5

[0078] The method of Example 1 is followed, except that the aqueous solution of the oxidizing agent contains only 5 wt % potassium permanganate; the rest is the same as Example 1, and a high-purity acetone product is finally obtained.

[0079] Example 6

[0080] The method of Example 1 is followed, except that the adsorption dehydration device is only filled with 5A molecular sieve; the rest is the same as Example 1, and finally a high-purity acetone product is obtained.

[0081] Example 7

[0082] The method of Example 1 is followed, except that the adsorption dehydration device is sequentially filled with only inorganic desiccant calcium chloride; the rest is the same as Example 1, and finally a high-purity acetone product is obtained.

[0083] Comparative Example 1

[0084] The method of Example 1 is followed, except that the first product material is directly pumped into an adsorption dehydration device for subsequent treatment steps; the rest is the same as Example 1, and finally an acetone product is obtained.

[0085] Table 1

[0086]

[0087] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing high-purity acetone, characterized in that: The preparation method comprises: S1, in the presence of an aqueous solution of an oxidizing agent, performing a first impurity removal treatment on the crude acetone product to obtain a first product material; S2: In the presence of an alkali metal hydroxide solution, the first product material is subjected to a second impurity removal treatment, and then subjected to post-treatment to obtain high-purity acetone.

2. The preparation method according to claim 1, wherein The aqueous solution of the oxidizing agent comprises an acidic oxidizing agent and water, and preferably also comprises a stabilizer; Preferably, the acidic oxidant comprises at least one of potassium permanganate, sodium dichromate, hydrogen peroxide and potassium perchlorate, preferably potassium permanganate and / or hydrogen peroxide; and / or The stabilizer is selected from at least one of polyphosphate, poly(alkyl)acrylate, gluconate and metasilicate. Preferably, the polyphosphate is selected from sodium pyrophosphate, and / or the poly(alkyl)acrylate is selected from sodium polyacrylate, and / or the gluconate is selected from sodium gluconate, and / or the metasilicate is selected from sodium metasilicate; and / or In the alkali metal hydroxide solution, the alkali metal hydroxide is selected from at least one of lithium hydroxide, sodium hydroxide and potassium hydroxide.

3. The preparation method according to claim 2, wherein In the aqueous solution of the oxidizing agent, the content of the acidic oxidant is 0.1-20wt%, preferably 1-10wt%, and more preferably 1-5wt%; and / or In the aqueous solution of the oxidizing agent, the content of the stabilizer is 0.1-20wt%, preferably 2-5wt%; and / or In the alkali metal hydroxide solution, the molar concentration of the alkali metal hydroxide is 0.5-5 mol / L.

4. The preparation method according to any one of claims 1 to 3, wherein The mass of the aqueous solution of the oxidizing agent is 0.1-1wt% of the mass of the crude acetone; and / or The mass of the alkali metal hydroxide solution is 0.1-1 wt % of the mass of the crude acetone.

5. The preparation method according to any one of claims 1 to 4, wherein: The acetone content in the crude acetone product is 98.5-99.9% by weight; The crude acetone also contains at least one of water, isopropanol, acetaldehyde, propionaldehyde, propylene, isopropyl ether, methanol and 4-hydroxy-4-methyl-2-pentanone.

6. The preparation method according to any one of claims 1 to 5, wherein: The conditions of the first impurity removal treatment include: a temperature of 15-50° C., and / or a time of 2-5 h; and / or The conditions of the second impurity removal treatment include: a temperature of 15-50° C., and / or a time of 0.5-2 h.

7. The preparation method according to any one of claims 1 to 6, wherein: The post-treatment includes dehydration, filtration, light removal and heavy removal; Preferably, the dehydration method includes adsorption separation dehydration; Preferably, the adsorbent in the adsorptive separation and dehydration comprises a molecular sieve and / or an inorganic salt desiccant, preferably a combination of a molecular sieve and an inorganic salt desiccant.

8. The preparation method according to claim 7, wherein: The molecular sieve is at least one of a 3A molecular sieve, a 4A molecular sieve and a 5A molecular sieve; and / or The inorganic salt desiccant is selected from at least one of calcium chloride, soda lime, quicklime and sodium hydroxide solids; and / or The method of adsorption separation and dehydration comprises: at room temperature, the second product material is contacted with an inorganic salt desiccant and a molecular sieve in sequence.

9. The preparation method according to claim 7 or 8, wherein: The conditions for removing lightness include: Operating pressure is 100-200 kPa; and / or A reflux ratio of 2-20; and / or The bottom temperature of the tower is 56.6℃-78.0℃.

10. The preparation method according to any one of claims 7 to 9, wherein: The conditions for weight loss include: Operating pressure is 100-200 kPa; and / or Reflux ratio of 0.2-5; and / or The tower top temperature is 55.7-77.5℃.

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