CN213467388U - Phosgene tail gas absorption system - Google Patents
Phosgene tail gas absorption system Download PDFInfo
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- CN213467388U CN213467388U CN202022242718.5U CN202022242718U CN213467388U CN 213467388 U CN213467388 U CN 213467388U CN 202022242718 U CN202022242718 U CN 202022242718U CN 213467388 U CN213467388 U CN 213467388U
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Abstract
The utility model relates to a phosgene tail gas absorption system, its characterized in that: the top of the primary graphite absorption tower is connected with a tail gas inlet pipe and a hydrogen chloride inlet pipe, a primary liquid discharge pipe at the bottom of the primary graphite absorption tower is connected to a storage tank, and a primary exhaust pipe at the lower part of the primary graphite absorption tower is connected to the top of the secondary graphite absorption tower; a secondary liquid discharge pipe at the bottom of the secondary graphite absorption tower is connected to the top of the primary graphite absorption tower; a secondary exhaust pipe at the top of the secondary graphite absorption tower is connected to the back-end process; a liquid outlet at the lower part of the storage tank is connected to a hydrochloric acid storage tank through a pump. The TDI production line keeps high-load stable operation, the concentration of the produced hydrochloric acid reaches 32 percent, the quality requirement of a finished product is met, a large amount of NaOH solution is not needed to destroy tail gas, the pressure of three-waste treatment is reduced, and clean production is realized.
Description
Technical Field
The utility model belongs to the technical field of the chemical industry, concretely relates to phosgene tail gas absorption system.
Background
Polyurethane is one of six synthetic materials with development prospect in the world, has the functions of wear resistance, low temperature resistance, oil resistance, ozone resistance and the like, and TDI is one of main production raw materials in the polyurethane industry. TDI (toluene diisocyanate) is generated by mixing TDA (toluene diamine) and DEIP (diiso-isophthalate) serving as a solvent and reacting with excessive phosgene, and meanwhile, a byproduct hydrogen chloride gas is produced, and a large amount of hydrogen chloride gas is sent to a later-stage process to process PVC. In order to ensure the production safety, phosgene tail gas and residual trace hydrogen chloride gas need to be destroyed by NaOH solution, and generated salt and water are discharged. Therefore, a large amount of NaOH solution needs to be consumed, and a large amount of acid-base wastewater is generated, so that the production cost is increased, and the pressure on environmental protection is also caused.
Disclosure of Invention
The utility model aims at absorbing phosgene and trace hydrogen chloride with the process water and then generating hydrochloric acid and selling, both having practiced thrift the NaOH solution, having reduced the formation volume of acid-base waste water again, selling hydrochloric acid and can also increasing economic benefits.
In order to achieve the purpose, the utility model adopts the technical proposal that: the utility model provides a phosgene tail gas absorption system, includes one-level graphite absorption tower, second grade graphite absorption tower, storage tank, its characterized in that: the top of the primary graphite absorption tower is connected with a tail gas inlet pipe and a hydrogen chloride inlet pipe, a primary liquid discharge pipe at the bottom of the primary graphite absorption tower is connected to a storage tank, and a primary exhaust pipe at the lower part of the primary graphite absorption tower is connected to the top of the secondary graphite absorption tower; a secondary liquid discharge pipe at the bottom of the secondary graphite absorption tower is connected to the top of the primary graphite absorption tower; a secondary exhaust pipe at the top of the secondary graphite absorption tower is connected to the back-end process; a liquid outlet at the lower part of the storage tank is connected with the hydrochloric acid storage tank through a pump, a return pipe is arranged at the outlet of the pump and is connected with the upper part of the first-level graphite absorption tower.
And an exhaust pipe is arranged at the top of the storage tank and is connected into a secondary exhaust pipe.
The upper part of the second-level graphite absorption tower is provided with a process water pipe
And the first-stage graphite absorption tower and the second-stage graphite absorption tower are connected with a cooling water inlet pipe and a cooling water return pipe for removing the heat of absorption of graphite in the towers.
The principle of the utility model is that: the phosgene tail gas firstly reacts with process water to generate dilute hydrochloric acid:
two-stage falling film absorbers are adopted, process water is used for absorbing the two-stage falling film absorbers to form dilute hydrochloric acid, and the dilute hydrochloric acid is absorbed by the two-stage falling film absorbers to generate hydrochloric acid with the concentration of more than 32% and is sold. The falling film absorption process absorbs gas through a liquid film in which absorption liquid flows along a wall in a descending mode under the action of gravity, has the advantages of large gas-liquid contact surface area, high mass transfer heat exchange efficiency, small flow, easiness in control and the like, effectively increases the absorption capacity of a tail gas absorption device, improves the absorption efficiency of tail gas, ensures the high-load stable operation of a TDI production line, and improves the intrinsic safety of a process system.
The utility model has the advantages that: the falling film absorption process is mature, the investment is small, and the labor intensity is reduced. The TDI production line keeps high-load stable operation, the concentration of the produced hydrochloric acid reaches 32 percent, the quality requirement of a finished product is met, and the TDI production line can be directly sold. Meanwhile, a large amount of NaOH solution is not needed to destroy tail gas, so that the NaOH solution is saved, the discharge amount of acid-base wastewater is reduced, the pressure of three-waste treatment is reduced, the production environment is protected, clean production is realized, and the method has strong practicability and popularization in the same industry.
Drawings
FIG. 1 is a schematic view of the present invention;
in the figure: w1-first-stage graphite absorption tower, W2-second-stage graphite absorption tower, D-storage tank, P-pump, E-hydrochloric acid storage tank, 1-tail gas inlet pipe, 2-hydrogen chloride inlet pipe, 3-first-stage exhaust pipe, 4-second-stage exhaust pipe, 5-exhaust pipe, 11-first-stage liquid discharge pipe, 12-second-stage liquid discharge pipe, 13-reflux pipe and 14-process water pipe.
Detailed Description
The principles and features of the present invention are described below in conjunction with the following drawings, the examples given are only intended to illustrate the present invention and are not intended to limit the scope of the present invention.
Example 1, see fig. 1, a phosgene tail gas absorption system, comprising a primary graphite absorption tower W1, a secondary graphite absorption tower W2, a storage tank D, characterized in that: the top of the primary graphite absorption tower W1 is connected with a tail gas inlet pipe 1 and a hydrogen chloride inlet pipe 2, a primary liquid discharge pipe 11 at the bottom of the primary graphite absorption tower W1 is connected with a storage tank D, and a primary exhaust pipe 3 at the lower part of the primary graphite absorption tower W1 is connected with the top of a secondary graphite absorption tower W2; a secondary liquid discharge pipe 12 at the bottom of the secondary graphite absorption tower W2 is connected to the top of the primary graphite absorption tower W1; a secondary exhaust pipe 4 at the top of the secondary graphite absorption tower W2 is connected to the later stage; a liquid outlet at the lower part of the storage tank D is connected to a hydrochloric acid storage tank E through a pump P, a return pipe 13 is arranged at the outlet of the pump P, and the return pipe 13 is connected to the upper part of the first-stage graphite absorption tower W1.
And an exhaust pipe 5 is arranged at the top of the storage tank D, and the exhaust pipe 5 is connected into a secondary exhaust pipe 4.
And a process water pipe 14 is arranged at the upper part of the secondary graphite absorption tower W2.
And the primary graphite absorption tower W1 and the secondary graphite absorption tower W2 are connected with a cooling water inlet pipe and a cooling water return pipe for removing the heat of absorption of graphite in the towers.
The working process is as follows: phosgene tail gas enters from the top of a primary graphite absorption tower W1 through a tail gas inlet pipe 1 and a hydrogen chloride inlet pipe 2, graphite is filled in a primary graphite absorption tower W1, phosgene is hydrolyzed into dilute hydrochloric acid, hydrogen chloride gas is absorbed into dilute hydrochloric acid, a large amount of absorption heat in the graphite is removed from cooling water, absorption liquid is collected into a storage tank D through a primary liquid discharge pipe 11, gas which is not completely absorbed by the primary graphite absorption tower W1 is sent to a secondary graphite absorption tower W2 through a primary liquid discharge pipe 3, pure process water is added into the secondary graphite absorption tower W2, graphite is filled in a secondary graphite absorption tower W2 for secondary absorption, the absorption heat in the graphite is removed from the cooling water, the absorbed liquid is sent to the top of the primary graphite absorption tower W1 through a secondary liquid discharge pipe 12 for hydrochloric acid concentration, the storage tank D and the secondary graphite absorption tower W2 exhaust gas are simultaneously sent to a back-stage process through a secondary liquid discharge pipe 4, and the product hydrochloric acid in the storage tank D is sent to, ready for sale.
Claims (4)
1. The utility model provides a phosgene tail gas absorption system, includes one-level graphite absorption tower (W1), second grade graphite absorption tower (W2), storage tank (D), its characterized in that: the top of the primary graphite absorption tower (W1) is connected with a tail gas inlet pipe (1) and a hydrogen chloride inlet pipe (2), a primary liquid discharge pipe (11) at the bottom of the primary graphite absorption tower (W1) is connected to a storage tank (D), and a primary exhaust pipe (3) at the lower part of the primary graphite absorption tower (W1) is connected to the top of the secondary graphite absorption tower (W2); a secondary liquid discharge pipe (12) at the bottom of the secondary graphite absorption tower (W2) is connected to the top of the primary graphite absorption tower (W1); a secondary exhaust pipe (4) at the top of the secondary graphite absorption tower (W2) is connected to the rear-stage process; a liquid outlet at the lower part of the storage tank (D) is connected to a hydrochloric acid storage tank (E) through a pump (P), a return pipe (13) is arranged at the outlet of the pump (P), and the return pipe (13) is connected to the upper part of the first-stage graphite absorption tower (W1).
2. The phosgene tail gas absorption system of claim 1, wherein: and an exhaust pipe (5) is arranged at the top of the storage tank (D), and the exhaust pipe (5) is connected into a secondary exhaust pipe (4).
3. The phosgene tail gas absorption system of claim 1, wherein: and a process water pipe (14) is arranged at the upper part of the secondary graphite absorption tower (W2).
4. The phosgene tail gas absorption system of claim 1, wherein: and the primary graphite absorption tower (W1) and the secondary graphite absorption tower (W2) are connected with a cooling water inlet pipe and a cooling water return pipe for removing the heat of absorption of graphite in the towers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022242718.5U CN213467388U (en) | 2020-10-11 | 2020-10-11 | Phosgene tail gas absorption system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022242718.5U CN213467388U (en) | 2020-10-11 | 2020-10-11 | Phosgene tail gas absorption system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213467388U true CN213467388U (en) | 2021-06-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022242718.5U Active CN213467388U (en) | 2020-10-11 | 2020-10-11 | Phosgene tail gas absorption system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN213467388U (en) |
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2020
- 2020-10-11 CN CN202022242718.5U patent/CN213467388U/en active Active
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