Reaction device for preparing phthalic anhydride by naphthalene method
By adding an electric heater and a steam turbine to the naphthalene method phthalic anhydride reaction device, the impurities on the catalyst are decomposed at high temperature and activated the catalyst, the problem of decreasing catalyst activity is solved, the catalyst regeneration and service life are achieved, and the energy saving and consumption reduction effect is achieved.
Patent Information
- Application Number
- CN202510058753.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-15
- Publication Date
- 2025-04-22
AI Technical Summary
In the production of phthalene anhydride by the existing naphthalene method, the catalyst activity decreases rapidly, resulting in a decrease in reaction efficiency, and the project volume of replacing the catalyst is huge, labor and material resources are consumed and cost high.
By adding an electric heater to heat the molten salt, the impurities on the catalyst are decomposed at high temperature, and the oxygen brought by the turbine air supply is used to activate the catalyst, redistribute it and restore activity, thereby extending the service life of the catalyst.
The catalyst regeneration is achieved, the service life of the catalyst is extended, the frequency of catalyst replacement is reduced, energy saving and consumption reduction is increased, and corporate benefits are increased.
Smart Images
Figure CN119857434A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chemical equipment, and in particular to a reaction device for preparing phthalic anhydride by a naphthalene process. Background Art
[0002] In the existing naphthalene process phthalic anhydride production, industrial naphthalene enters into naphthalene evaporator after naphthalene heater preheating, naphthalene steam enters into vaporizer together with preheated air and fully mixes and enters into reactor under the effect of catalyzer and carries out oxidation reaction, obtains phthalic anhydride and by-product naphthoquinone, maleic anhydride; After reaction product gas leaves reactor, first obtains crude phthalic anhydride by condenser condensation by gas cooler cooling, obtains finished product phthalic anhydride after purification. Reactor wherein is equipped with 18200 reaction tubes with an internal diameter of 25mm, the naphthalene oxidation phthalic anhydride 04-29 type catalyst of German BASF company development is filled with in the tube, the main component of catalyzer is vanadium pentoxide (V2O5) and titanium dioxide (TiO2), the activity of catalyzer in existing production decreases faster, and main reason is that first, vanadium ion can be polymeric state over a long period of time, and pentavalent state (5+) changes into low-activity tetravalent state (4+), and polymeric state is unfavorable for reaction; Second, catalyst surface impurities affect the catalytic action of catalyzer. Refilling the catalyst after it becomes less active would be a massive undertaking, consuming significant manpower and resources, and would cost a staggering $3 million. Therefore, other solutions were needed. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a naphthalene process phthalic anhydride reaction device, which overcomes the defects of the prior art, can regenerate the catalyst in the reactor, save energy and reduce consumption, and increase enterprise benefits.
[0004] In order to solve the above technical problems, the technical solution of the present invention is:
[0005] A naphthalene-based phthalic anhydride production reaction device comprises a naphthalene heater, a naphthalene evaporator, a vaporizer, a reactor, and a gas cooler, which are sequentially connected via pipelines and valves. The feed port of the vaporizer is also sequentially connected to an air preheater and a steam turbine via a pipeline. The reactor is provided with a temperature control jacket on its side wall, the temperature control medium inlet and the temperature control medium outlet of the temperature control jacket are respectively connected to a molten salt cooler via pipelines, and an electric heater is provided on the pipeline from the molten salt cooler to the temperature control medium inlet. An exhaust gas outlet is provided on the pipeline from the reactor to the gas outlet of the gas cooler, the exhaust gas outlet is provided with a sealing switch, and a blind plate is provided on the pipeline below the exhaust gas outlet.
[0006] Preferably, there are two molten salt coolers, symmetrically arranged on both sides of the reactor; and there are also two corresponding electric heaters.
[0007] Furthermore, the models of the electric heaters are BYG-380 / 1300 and BGY100-380 / 850, and the manufacturer is Zhenjiang Yutai Explosion-proof Electric Heater Co., Ltd.
[0008] Preferably, the electric heater is connected to an external power supply device.
[0009] Preferably, the exhaust gas outlet is connected to an exhaust gas treatment device through a pipeline.
[0010] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0011] After the present invention is shut down, the molten salt is heated by an additional electric heater, and the heated molten salt heats the catalyst in the reaction tube of the reactor, decomposing the impurities attached to the catalyst generated during the reaction at high temperature. At the same time, the steam turbine is turned on to supply air to the reactor. The high temperature and the oxygen brought by the steam turbine air supply (the activity of the catalyst becomes stronger as a result of the combined effect of the temperature rising to 400°C and the oxygen in the air supply, and the role of the steam turbine air supply is to transport oxygen to stimulate the activity of the catalyst) allow the catalyst to be redistributed, dispersed from the aggregated state, and converted from a tetravalent state to a pentavalent state, thereby activating the activity of the catalyst in the reactor and achieving the purpose of catalyst regeneration, thereby reducing the frequency of catalyst replacement and achieving the effect of energy saving and consumption reduction.
[0012] In short, the present invention can regenerate the catalyst in the reactor, save energy and reduce consumption, and increase enterprise benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 It is a schematic diagram of the equipment flow of an embodiment of the present invention;
[0014] In the figure, 1. Naphthalene heater; 2. Naphthalene evaporator; 3. Vaporizer; 4. Reactor; 5. Gas cooler; 6. Air preheater; 7. Steam turbine; 8. Molten salt cooler; 9. Electric heater; 10. Sealed switch; 11. Blind plate. DETAILED DESCRIPTION
[0015] The present invention will be further described below with reference to the accompanying drawings and examples.
[0016] like Figure 1Shown, a naphthalene process phthalic anhydride reaction unit comprises a naphthalene heater 1, a naphthalene evaporator 2, a vaporizer 3, a reactor 4 and a gas cooler 5 which are communicated with in sequence by pipeline (not shown), a valve (not shown); the feed port of the vaporizer 3 is also communicated with an air preheater 6 and a steam turbine 7 in sequence by pipeline; a temperature control jacket (not shown) is provided on the sidewall of the reactor 4, and a temperature control medium inlet (not shown) and a temperature control medium outlet (not shown) of the temperature control jacket are respectively communicated to a molten salt cooler 8 by pipeline, and an electric heater 9 is provided on the pipeline from the molten salt cooler 8 to the temperature control medium inlet; a waste gas outlet (not shown) is provided on the pipeline from the reactor 4 to the gas outlet of the gas cooler 5, and the waste gas outlet is provided with a sealing switch 10, and a blind plate 11 is provided on the pipeline at the waste gas outlet bottom.
[0017] In actual application, when the catalyst activity is found to have decreased to a certain level (the catalyst activity state can be determined by observing the decrease in the reaction hotspot), the equipment is shut down; the materials in the equipment are emptied, the blind plate 11 on the pipeline from the reactor 4 to the gas cooler 5 is closed, and the sealing switch 10 of the exhaust gas outlet is opened; the air preheater 6 and the steam turbine 7 are turned on to supply air at 20-30°C into the reactor 4 (using the oxygen in the air to oxidize the vanadium ions); at the same time, the molten salt cooler 8 and the electric heater 9 are turned on. The heated molten salt is used to maintain the temperature in the reactor 4 above 400°C for 12-24 hours, fully decomposing impurities on the catalyst and redistributing the vanadium ions in the catalyst in the reaction tubes of the reactor 4 (dispersing the aggregated state formed during the reaction), restoring the catalyst from the low-activity tetravalent state to the pentavalent state, thereby restoring the catalyst activity; the exhaust gas generated during this period is transported from the exhaust gas outlet to the exhaust gas treatment device (not shown). After the above treatment, the equipment can be restarted for production, which can improve the utilization rate of the catalyst, reduce the frequency of shutdowns due to catalyst, and achieve the effect of energy saving and consumption reduction.
[0018] It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.
Claims
1. A naphthalene process for preparing phthalic anhydride reaction device, characterized in that: The invention comprises a naphthalene heater, a naphthalene evaporator, a vaporizer, a reactor and a gas cooler which are connected in sequence through pipelines and valves; the feed port of the vaporizer is also connected in sequence with an air preheater and a steam turbine through a pipeline; a temperature control jacket is provided on the side wall of the reactor, a temperature control medium inlet and a temperature control medium outlet of the temperature control jacket are respectively connected to a molten salt cooler through pipelines, and an electric heater is provided on the pipeline from the molten salt cooler to the temperature control medium inlet; an exhaust gas outlet is provided on the pipeline from the reactor to the gas outlet of the gas cooler, a sealing switch is provided on the exhaust gas outlet, and a blind plate is provided on the pipeline at the lower part of the exhaust gas outlet.
2. The naphthalene-based phthalic anhydride reaction device as claimed in claim 1, wherein: The molten salt coolers are provided with two, which are symmetrically arranged on both sides of the reactor.
3. The naphthalene-based phthalic anhydride reaction device as claimed in claim 2, wherein: The corresponding electric heaters are also provided in two.
4. The naphthalene-based phthalic anhydride reaction device as claimed in claim 1, wherein: The electric heater is connected to an electrical supply of an external device.
5. The naphthalene-based phthalic anhydride reaction device as claimed in claim 1, wherein: The exhaust gas outlet is connected to the exhaust gas treatment device through a pipeline.