Phosgene synthesis replacement and catalyst drying device
By designing a phosgene synthesis replacement and drying catalyst device, the catalyst is replaced and dried using nitrogen heating components and reactors, which solves the problem of time and safety risks of activated carbon catalyst replacement, and achieves an efficient and safe catalyst replacement process.
Patent Information
- Application Number
- CN202422296592.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2025-08-12
- Estimated Expiration
- 2034-09-20
AI Technical Summary
In the production of toluene diisocyanate (TDI), the replacement and drying process of activated carbon catalysts takes a long time and poses safety risks. In the prior art, nitrogen replacement is uneven, which affects the replacement efficiency and safety.
A phosgene synthesis displacement and drying catalyst device is designed, including a nitrogen gas passage pipeline, a nitrogen heating assembly and a phosgene synthesis reactor. The catalyst is replaced and dried by heating nitrogen, and nitrogen is controlled by using a nitrogen cut-off valve, combined with a pressure transmitter and alkaline washing tower to treat toxic gases, and low-pressure steam or electrical energy is used to heat nitrogen to achieve efficient replacement and drying of the catalyst.
It shortens the catalyst replacement time, improves replacement efficiency and safety, simplifies operating procedures, and reduces safety risks.
Smart Images
Figure CN223209436U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of chemical engineering, and in particular relates to a phosgene synthesis replacement and drying catalyst device. Background Art
[0002] Toluene diisocyanate (TDI) production is commonly achieved through both phosgene and non-phosgene methods. The phosgene method uses phosgene as a raw material, imposing stringent quality requirements. Phosgene is primarily produced from carbon monoxide and chlorine in the presence of a catalyst. These raw materials contain impurities such as methane, water, hydrogen, and oxygen, which can reduce catalytic activity and even cause pulverization during the phosgene synthesis process. Activated carbon is one of the most commonly used traditional catalysts in industrial phosgene production. Decreased activity of activated carbon catalysts directly affects the phosgene synthesis reaction, leading to excessive chlorine content in the phosgene. This not only affects TDI production quality but also corrodes pipelines and equipment, causing damage and increasing maintenance costs. Therefore, regular replacement of the activated carbon catalyst is necessary. During activated carbon catalyst replacement, the carbon monoxide, chlorine, and phosgene present in the equipment during production are all highly toxic gases. Therefore, the atmosphere within the phosgene synthesis reactor must be completely replaced before replacing the activated carbon catalyst. The conventional replacement method uses steam to heat the phosgene synthesizer and introduces nitrogen into the phosgene synthesizer for replacement, which easily causes uneven temperature, which is not conducive to the release of toxic gases adsorbed by the activated carbon catalyst. The activated carbon catalyst is also not easy to dry, the replacement time is long, and the replacement efficiency is low, which affects the production of the device. Manual operation is used during the replacement process, which also prolongs the replacement time and poses a greater safety risk. Utility Model Content
[0003] The purpose of the utility model is to provide a phosgene synthesis replacement and drying catalyst device, aiming to solve the problems that the activated carbon catalyst is difficult to replace and dry when producing TDI by the phosgene method, the replacement process is time-consuming and the safety risk is relatively high.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a phosgene synthesis replacement and drying catalyst device, comprising: a nitrogen inlet pipe, a nitrogen heating component and a phosgene synthesis reactor, wherein the first end of the nitrogen inlet pipe is connected to an external nitrogen source, and the second end of the nitrogen inlet pipe is connected to the phosgene synthesis reactor, the nitrogen heating component is arranged on the outside of the nitrogen inlet pipe to heat the nitrogen inlet pipe, the nitrogen inlet pipe is provided with a nitrogen shut-off valve, and the phosgene synthesis reactor is also provided with a discharge pipe.
[0005] In a possible implementation, a first pressure transmitter is provided on the nitrogen inlet pipeline, and the first pressure transmitter is provided on a side of the nitrogen shut-off valve close to the nitrogen heating assembly.
[0006] In a possible implementation, the second end of the nitrogen inlet pipe is arranged on the feed pipe of the phosgene synthesis reactor.
[0007] In a possible implementation, a second pressure transmitter is provided on the nitrogen inlet pipeline, and the second pressure transmitter is provided at one end of the nitrogen inlet pipeline close to the phosgene synthesis reactor.
[0008] In a possible implementation, the discharge pipe is connected to an alkali washing pipe, and the alkali washing pipe is connected to an alkali washing tower.
[0009] In a possible implementation, a nitrogen regulating valve is provided on the alkali washing pipeline.
[0010] In a possible implementation, the nitrogen heating assembly includes a heating chamber, and the nitrogen inlet pipe is provided through the heating chamber.
[0011] In a possible implementation, the heating chamber is U-shaped, and the nitrogen inlet pipe is arranged along the length direction of the heating chamber.
[0012] In a possible implementation, the nitrogen heating component uses low-pressure steam or electric energy as a heating source.
[0013] In a possible implementation, the nitrogen gas introduced into the nitrogen inlet pipe is low-pressure nitrogen gas.
[0014] The beneficial effects of the phosgene synthesis replacement and drying catalyst device provided by the utility model are:
[0015] Compared with the prior art, the method comprises a nitrogen inlet pipe, a nitrogen heating component and a phosgene synthesis reactor, the phosgene synthesis reactor is used to produce phosgene, the nitrogen inlet pipe is connected to the phosgene synthesis reactor, the nitrogen heating component is arranged on the outside of the nitrogen inlet pipe, heats the nitrogen in the nitrogen inlet pipe, a nitrogen shut-off valve controls the introduction of nitrogen, the heated nitrogen enters the phosgene synthesis reactor, replaces the catalyst, and replaces the toxic gas adsorbed in the catalyst, and after the replacement is completed, the heated nitrogen continues to be introduced, and the heated nitrogen dries the phosgene synthesis reactor, the operation is simple, the replacement time is shortened, and the replacement efficiency and personnel safety are improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0017] Figure 1 This is a structural schematic diagram of a phosgene synthesis replacement and drying catalyst device provided in an embodiment of the present utility model.
[0018] In the figure: 1. Nitrogen inlet pipe; 2. Heating chamber; 3. First pressure transmitter; 4. Nitrogen shut-off valve; 5. Feed pipe; 6. Second pressure transmitter; 7. Phosgene synthesis reactor; 8. Discharge pipe; 9. Alkali washing pipe; 10. Nitrogen regulating valve. DETAILED DESCRIPTION
[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0020] Please refer to Figure 1 A specific embodiment of a phosgene synthesis replacement and drying catalyst device provided by the utility model is now described, comprising: a nitrogen inlet pipe 1, a nitrogen heating component and a phosgene synthesis reactor 7, wherein a first end of the nitrogen inlet pipe 1 is connected to an external nitrogen gas source, and a second end of the nitrogen inlet pipe 1 is connected to the phosgene synthesis reactor 7, the nitrogen heating component is arranged on the outside of the nitrogen inlet pipe 1 to heat the nitrogen inlet pipe 1, a nitrogen shut-off valve 4 is provided on the nitrogen inlet pipe 1, and a discharge pipe 8 is also provided on the phosgene synthesis reactor 7.
[0021] The utility model provides a phosgene synthesis replacement and drying catalyst device. Compared with the prior art, the utility model is provided with a nitrogen inlet pipe 1, a nitrogen heating component and a phosgene synthesis reactor 7. The phosgene synthesis reactor 7 is used to produce phosgene. The nitrogen inlet pipe 1 is connected to the phosgene synthesis reactor 7. The nitrogen heating component is arranged on the outside of the nitrogen inlet pipe 1 to heat the nitrogen in the nitrogen inlet pipe 1. The nitrogen shut-off valve 4 controls the introduction of nitrogen. The heated nitrogen enters the phosgene synthesis reactor 7 to replace the catalyst and replace the toxic gas adsorbed in the catalyst. After the replacement is completed, the heated nitrogen is continued to be introduced to dry the phosgene synthesis reactor 7. The utility model is simple to operate, shortens the replacement time, and improves the replacement efficiency and personnel safety.
[0022] For details, please refer to Figure 1 , including a nitrogen inlet pipe 1, a nitrogen heating component and a phosgene synthesis reactor 7, a nitrogen source is connected to a first end of the nitrogen inlet pipe 1, a second end of the nitrogen inlet pipe 1 is connected to the phosgene synthesis reactor 7, the nitrogen heating component is arranged at the first end of the nitrogen inlet pipe 1, and is arranged on the outside of the nitrogen inlet pipe 1 to heat the nitrogen inlet pipe 1, a nitrogen shut-off valve 4 is arranged on the nitrogen inlet pipe 1, for controlling the discharge of nitrogen, a discharge pipe 8 is provided on the side wall of the lower end of the phosgene synthesis reactor 7, the discharge pipe 8 is used to discharge phosgene and other toxic gases, control the heated nitrogen to enter the phosgene synthesis reactor 7, and replace the toxic gas adsorbed in the catalyst in the phosgene synthesis reactor 7, after the replacement is completed, continue to introduce the heated nitrogen, and the heated nitrogen dries the catalyst in the phosgene synthesis reactor 7, which is simple to operate, shortens the replacement time, and improves the replacement efficiency and personnel safety.
[0023] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 A first pressure transmitter 3 is provided on the nitrogen inlet pipeline 1, and the first pressure transmitter 3 is provided on a side of the nitrogen shut-off valve 4 close to the nitrogen heating component.
[0024] For details, please refer to Figure 1 The first pressure transmitter 3 is arranged on the nitrogen inlet pipeline 1, and is used to monitor the pressure of the nitrogen in the nitrogen inlet pipeline 1 in real time. The first pressure transmitter 3 is arranged between the nitrogen cut-off valve 4 and the nitrogen heating component, and is arranged close to the nitrogen heating component to facilitate the control of the nitrogen introduction amount and introduction time.
[0025] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 The second end of the nitrogen inlet pipe 1 is arranged on the feed pipe 5 of the phosgene synthesis reactor 7 .
[0026] For details, please refer to Figure 1 A feed pipe 5 is provided on the phosgene synthesis reactor 7, and the feed pipe 5 is arranged on the side wall of the upper end of the phosgene synthesis reactor 7. The second end of the nitrogen inlet pipe 1 is arranged on the feed pipe 5, so as to facilitate the discharge of the toxic gas used for producing phosgene in the feed pipe 5 into the phosgene synthesis reactor 7.
[0027] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 A second pressure transmitter 6 is provided on the nitrogen inlet pipeline 1 , and the second pressure transmitter 6 is provided at one end of the nitrogen inlet pipeline 1 close to the phosgene synthesis reactor 7 .
[0028] For details, please refer to Figure 1 The second pressure transmitter 6 is arranged on the nitrogen inlet pipe 1, and is arranged at one end of the nitrogen inlet pipe 1 close to the phosgene synthesis reactor 7, so as to facilitate real-time monitoring of the pressure of the nitrogen entering the feed pipe 5 and control of the amount and time of nitrogen introduced into the feed pipe 5.
[0029] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 The discharge pipe 8 is connected to an alkali washing pipe 9, and the alkali washing pipe 9 is connected to an alkali washing tower.
[0030] For details, please refer to Figure 1 The alkali washing pipe 9 is arranged on the discharge pipe 8, and the alkali washing pipe 9 is connected to the alkali washing tower. The nitrogen discharged from the phosgene synthesis reactor 7 enters the alkali washing tower through the alkali washing pipe 9 for treating toxic gases.
[0031] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 A nitrogen regulating valve 10 is provided on the alkali washing pipeline 9.
[0032] For details, please refer to Figure 1 A nitrogen regulating valve 10 is provided on the alkali washing pipeline 9. The nitrogen regulating valve 10 cooperates with the nitrogen cut-off valve 4 to facilitate the control of the nitrogen introduction amount and introduction time.
[0033] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 The nitrogen heating assembly includes a heating chamber 2, and a nitrogen inlet pipe 1 is set through the heating chamber 2.
[0034] For details, please refer to Figure 1 The nitrogen heating assembly includes a heating chamber 2, a nitrogen inlet pipe 1 is set through the left and right side walls of the heating chamber 2, and a heating source is set inside the heating chamber 2 to heat the nitrogen in the nitrogen inlet pipe 1 to improve the replacement efficiency.
[0035] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 The heating chamber 2 is U-shaped, and the nitrogen inlet pipe 1 is arranged along the length direction of the heating chamber 2.
[0036] For details, please refer to Figure 1The heating chamber 2 is U-shaped, and the heating chamber 2 is a U-shaped sleeve. The nitrogen inlet pipe 1 penetrates into the inner pipe of the heating chamber 2. A heating source is injected / set in the space between the inner pipe and the outer pipe of the heating chamber 2 to heat the nitrogen inlet pipe 1. The nitrogen inlet pipe 1 penetrates from one end of the U-shaped heating chamber 2 and passes through the other end of the U-shaped heating chamber 2 along the length direction of the heating chamber 2 to improve the heating efficiency of the nitrogen.
[0037] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 , the nitrogen heating component uses low-pressure steam or electric energy as the heating source.
[0038] For details, please refer to Figure 1 The heating source used by the nitrogen heating component can be low-pressure steam or electric energy. Low-pressure steam can be introduced into the heating chamber 2, or an electric heating wire can be set in the heating chamber 2 to heat the nitrogen.
[0039] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 The nitrogen introduced into pipeline 1 is low-pressure nitrogen.
[0040] For details, please refer to Figure 1 The nitrogen introduced into pipeline 1 is low-pressure nitrogen.
[0041] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 In the process of replacing the toxic gas adsorbed in the catalyst with low-pressure nitrogen, an "explosion" type intermittent replacement is adopted. The heated low-pressure nitrogen enters the phosgene synthesis reactor 7 to replace the toxic gas adsorbed in the catalyst. When the first pressure transmitter 3 and the second pressure transmitter 6 reach the upper limit of the pressure target setting value, the nitrogen cut-off valve 4 on the nitrogen inlet pipeline 1 is closed, and the nitrogen regulating valve 10 on the alkali washing pipeline 9 is opened to relieve the pressure. When the pressure relief reaches the lower limit of the pressure target setting value, the nitrogen regulating valve 10 is closed, and the nitrogen cut-off valve 4 is opened to continue to charge low-pressure nitrogen into the phosgene synthesis reactor 7. The above-mentioned pressure charging-pressure relief-pressure charging process is repeated until the phosgene content at the outlet of the discharge pipeline 8 of the phosgene synthesis reactor 7 is lower than 0.5ppm, and the replacement of the adsorbent is completed.
[0042] For further information, please refer to Figure 1During the replacement process, the temperature of the low-pressure nitrogen is between 25 and 147°C, the initial pressure of the low-pressure nitrogen introduced into the nitrogen introduction pipeline 1 is between 0 and 1.6 MPA, the upper limit of the pressure target setting value during the replacement process is between 0.085 and 0.9 MPA, and the lower limit of the pressure target setting value is between 0 and 0.085 MPA.
[0043] As a specific embodiment of the phosgene synthesis replacement and drying catalyst device provided by the present invention, please refer to Figure 1 During the catalyst drying process using low-pressure nitrogen, "explosion" intermittent drying is adopted. The heated low-pressure nitrogen enters the phosgene synthesis reactor 7 to dry the newly loaded catalyst. When the first pressure transmitter 3 and the second pressure transmitter 6 reach the upper limit of the pressure target setting value, the nitrogen cut-off valve 4 on the nitrogen inlet pipeline 1 of the phosgene synthesis reactor 7 is closed, and the nitrogen regulating valve 10 on the alkali washing pipeline 9 is opened to release the pressure. When the pressure relief reaches the lower limit of the pressure target setting value, the nitrogen regulating valve 10 is closed, and the nitrogen cut-off valve 4 is opened to continue to charge low-pressure nitrogen into the phosgene synthesis reactor 7. The above-mentioned pressure charging-pressure relief-pressure charging process is repeated until the water amount at the outlet of the discharge pipeline 8 of the phosgene synthesis reactor 7 reaches the dew point requirement, and the drying of the adsorbent is completed.
[0044] For further information, please refer to Figure 1 During the drying process of the adsorbent, the dew point temperature at the outlet of the discharge pipe 8 of the phosgene synthesis reactor 7 is between -30 and -40°C.
[0045] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A phosgene synthesis replacement and drying catalyst device, characterized in that: include: A nitrogen inlet pipe, a nitrogen heating assembly, and a phosgene synthesis reactor, wherein the first end of the nitrogen inlet pipe is connected to an external nitrogen source, and the second end of the nitrogen inlet pipe is connected to the phosgene synthesis reactor. The nitrogen heating assembly is arranged on the outside of the nitrogen inlet pipe to heat the nitrogen inlet pipe. A nitrogen shut-off valve is provided on the nitrogen inlet pipe, and a discharge pipe is also provided on the phosgene synthesis reactor.
2. A phosgene synthesis replacement and drying catalyst device according to claim 1, characterized in that: The nitrogen inlet pipeline is provided with a first pressure transmitter, and the first pressure transmitter is arranged on a side of the nitrogen shut-off valve close to the nitrogen heating component.
3. A phosgene synthesis replacement and drying catalyst device according to claim 1, characterized in that: The second end of the nitrogen inlet pipe is arranged on the feed pipe of the phosgene synthesis reactor.
4. A phosgene synthesis replacement and drying catalyst device according to claim 3, characterized in that: The nitrogen inlet pipeline is provided with a second pressure transmitter, and the second pressure transmitter is arranged at one end of the nitrogen inlet pipeline close to the phosgene synthesis reactor.
5. The phosgene synthesis replacement and drying catalyst device according to claim 1, characterized in that: The discharge pipe is connected to an alkali washing pipe, and the alkali washing pipe is connected to an alkali washing tower.
6. A phosgene synthesis replacement and drying catalyst device according to claim 5, characterized in that: The alkali washing pipeline is provided with a nitrogen regulating valve.
7. The phosgene synthesis replacement and drying catalyst device according to claim 1, characterized in that: The nitrogen heating assembly comprises a heating chamber, and the nitrogen inlet pipe is arranged through the heating chamber.
8. A phosgene synthesis replacement and drying catalyst device according to claim 7, characterized in that: The heating chamber is arranged in a U shape, and the nitrogen inlet pipe is arranged along the length direction of the heating chamber.
9. The phosgene synthesis replacement and drying catalyst device according to claim 1, characterized in that: The nitrogen heating component uses low-pressure steam or electric energy as a heating source.
10. The phosgene synthesis replacement and drying catalyst device according to claim 1, characterized in that: The nitrogen introduced into the nitrogen inlet pipeline is low-pressure nitrogen.