Method for recovering hydrochloric acid from distillation residue of trichloroacetyl chloride or chloroacetyl chloride

Abstract

A method for recovering hydrochloric acid from distillation still residue of trichloroacetyl chloride or chloroacetyl chloride comprises the following steps: 0-50 kg of catalyst is mixed into each ton of distillation still residue to form a mixture, wherein the distillation still residue contains a polymer of trichloroacetyl chloride or a polymer of chloroacetyl chloride, the mixture is dry distilled at 200-800° C. for 0.5-3 hours, the polymer of trichloroacetyl chloride or the polymer of chloroacetyl chloride is catalytically cracked, and tail gas containing gaseous hydrogen chloride is generated, wherein the catalyst is ferric chloride or manganese chloride or a mixture of ferric chloride and manganese chloride, a dry distillation process is introduced, manganese chloride and ferric chloride are used as catalysts, the catalyst is mixed with the distillation still residue, the mixture is catalytically cracked in an anaerobic environment, and the mixture is dry distilled and decomposed into hydrogen chloride, sulfur dioxide and carbon dioxide, wherein the generated hydrogen chloride accounts for about 30-70% of the total weight of the distillation still residue, the sulfur dioxide accounts for about 10-50%, and the carbon dioxide accounts for 10-50%, and finally the hydrogen chloride is absorbed to generate hydrochloric acid for recovery.

Description

Technical Field

[0001] The invention relates to the technical field of polymer catalytic cracking, and in particular to a method for recovering hydrochloric acid from distillation still residue of trichloroacetyl chloride or chloroacetyl chloride. Background Art

[0002] Trichloroacetyl chloride and chloroacetyl chloride are both obtained by chlorination and distillation of raw materials. Trichloroacetyl chloride is made from chloroacetic acid mother liquor as raw material, after dehydration and low boiling, preliminary chlorination, then acylation, deep chlorination with 2-methylpyridine as catalyst, and then distillation to obtain trichloroacetyl chloride, wherein the main components of chloroacetic acid mother liquor are dichloroacetic acid, trichloroacetic acid, chloroacetyl chloride, dichloroacetyl chloride, trichloroacetyl chloride, and sulfur is used in the preliminary chlorination. During distillation, trichloroacetyl chloride vapor escapes from the top of the distillation kettle, and the finished product trichloroacetyl chloride is obtained by condensation, and the distillation kettle residue is formed at the bottom of the distillation kettle, and this distillation kettle residue is a polymer of trichloroacetyl chloride and unchlorinated sulfur. Chloroacetyl chloride is made from chloroacetic acid and sulfur as raw materials, and acylation is used to obtain chloroacetyl chloride. During distillation, chloroacetyl chloride vapor escapes from the top of the distillation tower, and the finished product chloroacetyl chloride is obtained by condensation, and the distillation kettle residue is also formed at the bottom of the distillation kettle, and this distillation kettle residue is a polymer of chloroacetyl chloride and unchlorinated sulfur. However, the above two distillation reactor residues are both treated as hazardous wastes in the prior art. Summary of the invention

[0003] In view of this, in view of the above-mentioned shortcomings, it is necessary to propose a method for recovering hydrochloric acid from the distillation residue of trichloroacetyl chloride or chloroacetyl chloride.

[0004] A method for recovering hydrochloric acid from distillation still residue of trichloroacetyl chloride or chloroacetyl chloride comprises the following steps: 0-50 kg of a catalyst is mixed into each ton of distillation still residue to form a mixture, wherein the distillation still residue contains a polymer of trichloroacetyl chloride or a polymer of chloroacetyl chloride; the mixture is dry-distilled at 200-800° C. for 0.5-3 hours to catalytically crack the polymer of trichloroacetyl chloride or the polymer of chloroacetyl chloride to generate tail gas containing gaseous hydrogen chloride; the catalyst is ferric chloride or manganese chloride or a mixture of ferric chloride and manganese chloride.

[0005] Preferably, 30 kg of catalyst is mixed into each ton of rectification still residue to form a mixture.

[0006] Preferably, the mixture is dry distilled at 200°C-600°C.

[0007] Preferably, the mixture is dry distilled for 1-3 hours.

[0008] Preferably, the method is implemented based on an apparatus for recovering hydrochloric acid from the distillation residue of trichloroacetyl chloride or chloroacetyl chloride, the apparatus for recovering hydrochloric acid from the distillation residue of trichloroacetyl chloride or chloroacetyl chloride comprises a mixing tank, a converter, an absorption tower, a desulfurization tower, and a collecting bin, the outlet of the mixing tank is connected to the inlet of the converter, the gas phase outlet of the converter is connected to the inlet of the absorption tower, the outlet of the absorption tower is connected to the inlet of the desulfurization tower, and the solid phase outlet of the converter is connected to the inlet of the collecting bin.

[0009] Preferably, the distillation still residue and the catalyst are mixed in a mixing tank.

[0010] Preferably, the mixture is dry distilled in a converter, and the oxygen content in the converter is 0-5%.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] By introducing the dry distillation process, manganese chloride and ferric chloride are used as catalysts. After the catalyst is mixed with the distillation kettle residue, it is catalytically cracked in an anaerobic environment and decomposed into hydrogen chloride, sulfur dioxide and carbon dioxide by dry distillation. The generated hydrogen chloride accounts for about 30-70% of the total weight of the distillation kettle residue, sulfur dioxide accounts for about 10-50%, and carbon dioxide accounts for 10-50%. Finally, hydrogen chloride is absorbed to generate hydrochloric acid for recovery. Converting hazardous waste into solid waste greatly reduces the treatment cost, recovers hydrogen chloride and converts it into industrial hydrochloric acid, and improves economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The present invention is a schematic structural diagram of the equipment for recovering hydrochloric acid from the residual liquid in the distillation kettle of trichloroacetyl chloride or chloroacetyl chloride.

[0014] In the figure: a mixing tank 10, a converter 20, an absorption tower 30, a desulfurization tower 40, and a collecting bin 50. DETAILED DESCRIPTION

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] The embodiment of the present invention provides a method for recovering hydrochloric acid from distillation still residue of trichloroacetyl chloride or chloroacetyl chloride. 0-50 kg of catalyst is mixed into each ton of distillation still residue to form a mixture. The distillation still residue contains a polymer of trichloroacetyl chloride or a polymer of chloroacetyl chloride. The mixture is dry distilled at 200° C. to 800° C. for 0.5 to 3 hours to catalytically crack the polymer of trichloroacetyl chloride or the polymer of chloroacetyl chloride to generate tail gas containing gaseous hydrogen chloride. The catalyst is ferric chloride or manganese chloride or a mixture of ferric chloride and manganese chloride.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] By introducing the dry distillation process, manganese chloride and ferric chloride are used as catalysts. After the catalyst is mixed with the distillation kettle residue, it is catalytically cracked in an anaerobic environment and decomposed into hydrogen chloride, sulfur dioxide and carbon dioxide by dry distillation. The generated hydrogen chloride accounts for about 30-70% of the total weight of the distillation kettle residue, sulfur dioxide accounts for about 10-50%, and carbon dioxide accounts for 10-50%. Finally, hydrogen chloride is absorbed to generate hydrochloric acid for recovery. Converting hazardous waste into solid waste greatly reduces the treatment cost, recovers hydrogen chloride and converts it into industrial hydrochloric acid, and improves economic benefits.

[0019] Furthermore, 30 kg of catalyst was mixed into each ton of the distillation still residue to form a mixture.

[0020] Further, the mixture is dry distilled at 200°C-600°C.

[0021] Further, the mixture is dry distilled for 1-3 hours.

[0022] See also Figure 1 Further, the method is implemented based on a device for recovering hydrochloric acid from the distillation residue of trichloroacetyl chloride or chloroacetyl chloride, and the device for recovering hydrochloric acid from the distillation residue of trichloroacetyl chloride or chloroacetyl chloride comprises a mixing tank 10, a converter 20, an absorption tower 30, a desulfurization tower 40, and a collecting bin 50, wherein the outlet of the mixing tank 10 is connected to the inlet of the converter 20, the gas phase outlet of the converter 20 is connected to the inlet of the absorption tower 30, the outlet of the absorption tower 30 is connected to the inlet of the desulfurization tower 40, and the solid phase outlet of the converter 20 is connected to the inlet of the collecting bin 50. The mixing tank 10, the converter 20, the absorption tower 30, the desulfurization tower 40, and the collecting bin 50 are all conventional structures in the prior art and will not be described in detail.

[0023] See also Figure 1 Further, the distillation reactor residue and the catalyst are mixed in the mixing tank 10.

[0024] See also Figure 1 Further, the mixture is dry-distilled in a converter 20, and the oxygen content in the converter 20 is 0-5%.

[0025] The tail gas contains hydrogen chloride, sulfur dioxide and carbon dioxide. After the residual liquid in the rectification kettle is dry-distilled, solid residue is generated and enters the collection bin 50. The hydrogen chloride and sulfur dioxide in the tail gas are cooled and absorbed by the absorption tower 30, and the unabsorbed sulfur dioxide is desulfurized by the desulfurization tower 40 and then discharged. The operating temperature of the absorption tower 30 is 50-60°C, the absorption tower 30 operates at normal pressure, and the absorption tower 30 uses water as an absorbent.

[0026] The method for determining sulfur dioxide is as follows: after the tail gas is absorbed by sodium hydroxide, titration is performed with reference to GB / T5009.34-2003.

[0027] The method for determining hydrogen chloride is: after the tail gas is absorbed by sodium hydroxide, titration is performed with reference to GB / T12457-90.

[0028] The method for determining carbon dioxide is: refer to GB / T20566-2006 and perform titration.

[0029] The present invention is further described below by way of examples and comparative examples. The following examples are only used to illustrate the present invention in detail and are not intended to limit the scope of protection of the invention in any way.

[0030] Example 1

[0031] 30 kg of catalyst, including 30 kg of ferric chloride and 0 kg of manganese chloride, was added to each ton of trichloroacetyl chloride distillation kettle residue. After being fully mixed, the catalyst was uniformly added into a converter 20 and dry distilled at 200°C for 3 hours. The final product was treated by a device for recovering hydrochloric acid from the distillation kettle residue of trichloroacetyl chloride or chloroacetyl chloride to obtain 85 kg of solid residue, 452.3 kg of hydrogen chloride, 156.8 kg of sulfur dioxide and 290.1 ​​kg of carbon dioxide.

[0032] 30 kg of catalyst, including 30 kg of ferric chloride and 0 kg of manganese chloride, was added to each ton of chloroacetyl chloride distillation kettle residue. After being fully mixed, the catalyst was uniformly added into a converter 20 and dry distilled at 200°C for 3 hours. The final product was treated by a device for recovering hydrochloric acid from the distillation kettle residue of trichloroacetyl chloride or chloroacetyl chloride to obtain 93 kg of solid residue, 429.8 kg of hydrogen chloride, 183.1 kg of sulfur dioxide and 287.4 kg of carbon dioxide.

[0033] Example 2

[0034] 30 kg of catalyst, including 20 kg of ferric chloride and 10 kg of manganese chloride, was added to each ton of trichloroacetyl chloride distillation kettle residue. After being fully mixed, the catalyst was uniformly added into a converter 20 and dry distilled at 400° C. for 2 hours. The final product was treated by a device for recovering hydrochloric acid from the distillation kettle residue of trichloroacetyl chloride or chloroacetyl chloride to obtain 87 kg of solid residue, 445.3 kg of hydrogen chloride, 147.5 kg of sulfur dioxide and 310.6 kg of carbon dioxide.

[0035] 30 kg of catalyst, including 30 kg of ferric chloride and 0 kg of manganese chloride, was added to each ton of chloroacetyl chloride distillation kettle residue. After being fully mixed, the catalyst was added into a converter 20 at a uniform speed and dry distilled at 200°C for 3 hours. The final product was treated by a device for recovering hydrochloric acid from the distillation kettle residue of trichloroacetyl chloride or chloroacetyl chloride to obtain 91 kg of solid residue, 418.8 kg of hydrogen chloride, 176.4 kg of sulfur dioxide and 303.5 kg of carbon dioxide.

[0036] Example 3

[0037] 30 kg of catalyst, including 15 kg of ferric chloride and 15 kg of manganese chloride, was added to each ton of trichloroacetyl chloride distillation kettle residue. After being fully mixed, the catalyst was uniformly added into a converter 20 and dry distilled at 600°C for 1 hour. The final product was treated by a device for recovering hydrochloric acid from the distillation kettle residue of trichloroacetyl chloride or chloroacetyl chloride to obtain 89 kg of solid residue, 449.2 kg of hydrogen chloride, 150.7 kg of sulfur dioxide and 297.8 kg of carbon dioxide.

[0038] 30 kg of catalyst, including 30 kg of ferric chloride and 0 kg of manganese chloride, was added to each ton of chloroacetyl chloride distillation kettle residue. After being fully mixed, the catalyst was uniformly added into a converter 20 and dry distilled at 200°C for 3 hours. The final product was treated by a device for recovering hydrochloric acid from the distillation kettle residue of trichloroacetyl chloride or chloroacetyl chloride to obtain 95 kg of solid residue, 421.2 kg of hydrogen chloride, 181.1 kg of sulfur dioxide and 291.6 kg of carbon dioxide.

[0039] Comparative Example 1

[0040] 0 kg of catalyst, including 0 kg of ferric chloride and 0 kg of manganese chloride, was added into a converter 20 at a uniform speed for each ton of trichloroacetyl chloride distillation still residue, and after being fully mixed, dry distillation was carried out at 500° C. for 1.5 hours. The final product was treated by a device for recovering hydrochloric acid from the distillation still residue of trichloroacetyl chloride or chloroacetyl chloride to obtain 264 kg of solid residue, 52.1 kg of hydrogen chloride, 54.2 kg of sulfur dioxide, 170.5 kg of carbon dioxide and 459.2 kg of other components.

[0041] 30 kg of catalyst, including 30 kg of ferric chloride and 0 kg of manganese chloride, was added to each ton of chloroacetyl chloride distillation kettle residue. After being fully mixed, the catalyst was added into a converter 20 at a uniform speed and dry distilled at 200°C for 3 hours. The final product was treated by a device for recovering hydrochloric acid from the distillation kettle residue of trichloroacetyl chloride or chloroacetyl chloride to obtain 305 kg of solid residue, 374 kg of hydrogen chloride, 68.2 kg of sulfur dioxide, 117.7 kg of carbon dioxide and 471.7 kg of other components.

[0042] The steps in the method of the embodiment of the present invention can be adjusted in order, combined or deleted according to actual needs.

[0043] The modules or units in the device of the embodiment of the present invention may be combined, divided or deleted according to actual needs.

[0044] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for recovering hydrochloric acid from the distillation residue of trichloroacetyl chloride or chloroacetyl chloride, Features: 30 kg of catalyst is mixed into each ton of distillation still residue to form a mixture, wherein the distillation still residue contains a polymer of trichloroacetyl chloride or a polymer of chloroacetyl chloride, and the mixture is dry-distilled at 200° C.-800° C. for 0.5-3 hours to catalytically crack the polymer of trichloroacetyl chloride or the polymer of chloroacetyl chloride in an anaerobic environment to generate tail gas containing gaseous hydrogen chloride, and the tail gas containing gaseous hydrogen chloride is converted into industrial hydrochloric acid, wherein the catalyst is ferric chloride or manganese chloride or a mixture of ferric chloride and manganese chloride.

2. The method for recovering hydrochloric acid from the distillation bottoms of trichloroacetyl chloride or chloroacetyl chloride as claimed in claim 1, Features: The mixture is dry distilled at 200°C-600°C.

3. The method for recovering hydrochloric acid from the distillation bottoms of trichloroacetyl chloride or chloroacetyl chloride as claimed in claim 1, Features: The mixture was dry distilled for 1-3 hours.

4. The method for recovering hydrochloric acid from the distillation bottoms of trichloroacetyl chloride or chloroacetyl chloride as claimed in claim 1, Features: The method is implemented based on a device for recovering hydrochloric acid from the distillation still residue of trichloroacetyl chloride or chloroacetyl chloride. The device comprises a mixing tank, a converter, an absorption tower, a desulfurization tower, and a collecting bin. The outlet of the mixing tank is connected to the inlet of the converter, the gas phase outlet of the converter is connected to the inlet of the absorption tower, the outlet of the absorption tower is connected to the inlet of the desulfurization tower, and the solid phase outlet of the converter is connected to the inlet of the collecting bin.

5. A method for recovering hydrochloric acid from the distillation bottoms of trichloroacetyl chloride or chloroacetyl chloride as claimed in claim 4, Features: The distillation still residue and the catalyst are mixed in a mixing tank.

6. A method for recovering hydrochloric acid from the distillation bottoms of trichloroacetyl chloride or chloroacetyl chloride as claimed in claim 4, Features: The mixture is dry distilled in a converter, and the oxygen content in the converter is 0-5%.

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