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WO2024149204A1 - 一种顺酐装置副产高压或超高压蒸汽的装置及其生产方法 - Google Patents

一种顺酐装置副产高压或超高压蒸汽的装置及其生产方法 Download PDF

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Publication number
WO2024149204A1
WO2024149204A1 PCT/CN2024/071196 CN2024071196W WO2024149204A1 WO 2024149204 A1 WO2024149204 A1 WO 2024149204A1 CN 2024071196 W CN2024071196 W CN 2024071196W WO 2024149204 A1 WO2024149204 A1 WO 2024149204A1
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Prior art keywords
pressure
cooler
ultra
molten salt
pressure steam
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PCT/CN2024/071196
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English (en)
French (fr)
Inventor
吴非克
张文明
陈虎
朱如意
董洪江
周一飞
陈霞
徐志刚
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常州瑞华化工工程技术股份有限公司
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Publication of WO2024149204A1 publication Critical patent/WO2024149204A1/zh
Priority to US18/809,731 priority Critical patent/US12372231B2/en

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
    • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
    • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
    • C07D307/56—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D307/60—Two oxygen atoms, e.g. succinic anhydride
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0006—Controlling or regulating processes
    • B01J19/0013—Controlling the temperature of the process
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/06—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being molten; Use of molten metal, e.g. zinc, as heat transfer medium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00—Component parts or details of steam boilers
    • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/26—Steam-separating arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00—Component parts or details of steam boilers
    • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/34—Adaptations of boilers for promoting water circulation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
    • F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00054—Controlling or regulating the heat exchange system
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
    • B01J2219/00103—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor in a heat exchanger separate from the reactor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Definitions

  • the invention relates to the technical field of maleic anhydride production, and in particular to a device for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device and a production method thereof.
  • Maleic anhydride also known as maleic anhydride
  • maleic anhydride is an important organic chemical raw material and the third largest organic anhydride in the world after phthalic anhydride and acetic anhydride. It is widely used in petrochemical, food processing, medicine, building materials and other industries.
  • BDO 1,4-butanediol
  • the production methods of maleic anhydride can be divided into benzene oxidation method and n-butane oxidation method.
  • the traditional process is mainly based on benzene oxidation, but due to the anti-carcinogenicity of benzene and the high cost of raw materials, the current new devices all use n-butane as raw material.
  • a typical device for producing maleic anhydride by oxidation of n-butane basically includes a reaction unit and a post-treatment unit. The typical reaction unit flow is shown in Figure 6, where n-butane and air undergo catalytic oxidation reaction to produce maleic anhydride.
  • the mixing ratio of n-butane to air is usually 1.5-2.1 mol%, and the reaction uses a V/P system catalyst.
  • the reaction temperature is 400-430°C, and the hot spot temperature of the reactor is usually 420-480°C.
  • the reactor adopts a tubular fixed bed reactor, and the reaction heat is withdrawn by the circulating molten salt outside the reaction tube to control the temperature of the oxidation reaction.
  • the heated molten salt outside the reaction tube enters the molten salt cooler, and the hot molten salt vaporizes the water in the molten salt cooler to produce saturated steam.
  • the reaction heat of the oxidation reactor is produced in the form of steam.
  • the gas temperature at the reactor outlet is about 390-435°C.
  • the maleic anhydride post-processing unit After being cooled to 130-160°C by the reaction gas cooler (gas cooler) and the switching cooler (switching cooler), it enters the maleic anhydride post-processing unit.
  • the maleic anhydride in the reaction gas is absorbed and then enters the desorption tower for desorption to obtain crude maleic anhydride, which is then refined to obtain maleic anhydride products.
  • the hourly byproduct steam of the reaction unit will reach 2 million to 2.2 million tons/year, which is 10 to 11 times larger than the production scale of the main product maleic anhydride. Its economic efficiency is even equal to or better than that of the main product maleic anhydride in some cases in the market. Therefore, maximizing the use of the reaction heat of the maleic anhydride unit and maximizing the byproduct steam with higher grade and more economic benefits are of great significance to improving the economic efficiency of the maleic anhydride unit.
  • n-butane-based maleic anhydride units that have been put into production currently mainly produce 4.0-5.5MPag steam as a by-product, but this is insufficient and inefficient for utilizing the reaction heat of n-butane oxidation.
  • the main reason is that the typical reaction temperature of n-butane oxidation reaction is 400-430°C, and the temperature of the hot molten salt entering the molten salt cooler is also maintained at 400-430°C, while the saturation temperature of 4.0-5.5MPag water vapor is 252-265°C, and the heat transfer temperature difference between the cold and hot sides is as high as 135-178°C, which is extremely unreasonable in the cascade utilization of energy consumption.
  • Huizhou Yuxin Chemical Co., Ltd. recently succeeded in trying to produce higher pressure steam ( ⁇ 8MPag) on its newly commissioned maleic anhydride unit, there is still a lot of room for improvement in terms of reasonably setting the heat transfer temperature difference and effectively utilizing the reaction heat.
  • the heated side logistics can be heated to ⁇ 380°C at most. If the heated side logistics is water, the n-butane oxidation unit can produce a maximum of 22MPag of subcritical or supercritical steam. Generally, steam of 6-12MPag can be called high-pressure steam, steam of 12-16MPag can be called ultra-high-pressure steam, and steam >17MPag can be called subcritical or supercritical steam.
  • the n-butane process maleic anhydride unit can produce steam up to 22MPag from the perspective of heat transfer temperature difference
  • the n-butane process maleic anhydride unit is mainly for the production of maleic anhydride, and the by-product steam is a secondary purpose. Therefore, in addition to considering the heat transfer temperature difference, the operability of the unit should also be considered to ensure the stable and reliable operation of the n-butane process maleic anhydride unit. Therefore, generally speaking, it is feasible and economical to make the operating heat transfer temperature difference wider (30-40°C) from a process perspective.
  • the n-butane process maleic anhydride reaction unit considering the initial high activity of the catalyst and the low operating temperature ( ⁇ 390°C), it is possible for the n-butane process maleic anhydride reaction unit to produce ultra-high pressure steam of up to 350°C and 16.5Mpa while ensuring the normal production of the n-butane oxidation maleic anhydride unit.
  • the higher steam production pressure and temperature have higher requirements for boiler water quality, according to the requirements of GB12145-2016, it is more appropriate to determine the maximum pressure of steam in the n-butane process maleic anhydride unit at 15.6MPag.
  • the oxidation reaction of the current n-butane process maleic anhydride unit all uses a V/P system catalyst, which can make n-butane generate maleic anhydride with high selectivity, but the significant disadvantage is that the strength is poor, dust will be blown out during normal production, and a small amount of high freezing point tar will be accompanied at the reactor outlet. Therefore, in order to avoid the accumulation of these dust and tar in the equipment, in the traditional scheme, the cooling of the process gas after the reaction is divided into two stages, namely the primary cooler (also called gas cooler) and the secondary cooler (also called switching cooler), and the process gas is heat exchanged in the tube side of the cooler.
  • the primary cooler also called gas cooler
  • the secondary cooler also called switching cooler
  • the primary cooler is to reduce the dead zone and prevent the accumulation of catalyst dust in the equipment, while the secondary cooler needs to be switched and cleaned regularly (because the high freezing point tar will precipitate and adhere to the inner wall of the heat exchange tube during the cooling process, causing the heat transfer effect to deteriorate rapidly), so for the convenience of cleaning, the process gas is also designed in the tube side.
  • the shell side of the primary cooler and the secondary cooler is used to preheat the boiler feed water and generate 4-5.5MPag steam. This design is reasonable and has been verified in the existing operating device.
  • the gas cooler and the switching cooler adopt a fixed tube sheet structure, and the process gas flows through the tube side to prevent blockage or facilitate cleaning, but this also brings new problems. Since both the gas cooler and the switching cooler are fixed tube sheet structures, and the temperature difference between the shell and tube of the gas cooler and the switching cooler is large, and the operating conditions change, expansion joints need to be set on the shell side of the equipment to absorb the difference in expansion caused by the different temperatures of the shell and tube, so as to avoid damage to the equipment caused by excessive stress. This is feasible when the traditional by-product is 4-5.5MPag medium-pressure steam, but if higher pressure steam is to be produced, the operation and design pressure of the shell side will increase, which will make the design and manufacture of the shell side expansion joint difficult and difficult to implement. Even if it is barely achieved, it will significantly increase the investment in the device and the risk of equipment.
  • the temperature difference between the shell and tube of the molten salt cooler is much smaller than that of the by-product steam of 4-5.5MPag, so the required heat exchange area of the equipment will be much larger, which means that the diameter and length of the molten salt cooler need to be increased.
  • the increase in equipment diameter will lead to a rapid increase in investment, and the equipment diameter cannot be increased indefinitely. Blindly increasing the equipment will not only lead to a substantial increase in equipment investment, but will also cause manufacturing difficulties and cannot be implemented.
  • the present invention provides a device for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device and a production method thereof, so as to solve the problem that it is difficult and costly to produce high-pressure or ultra-high-pressure steam with conventional equipment.
  • the object of the present invention is to provide a device for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device and a production method thereof, so as to reduce the difficulty and production cost of producing high-pressure or ultra-high-pressure steam.
  • the present invention provides the following solutions:
  • a device for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device comprising an ultra-high-pressure steam drum and a first path and a second path respectively connected in parallel with the ultra-high-pressure steam drum, wherein the first path comprises a molten salt pump, an oxidation reactor, a regulating valve and a molten salt cooler connected in sequence, and the second path comprises a A switching cooler and a gas cooler are connected, and a boiler water buffer device and a boiler water booster pump are sequentially arranged and connected between the switching cooler and the gas cooler.
  • the boiler water buffer device is a boiler water buffer tank or a high-pressure deaerator.
  • the gas cooler includes a first shell, a first boiler water inlet and a first boiler water outlet arranged at the top of the first shell, a process gas outlet arranged at the bottom of the first shell, a process gas inlet arranged at the side of the first shell, and a plurality of U-shaped tube bundles and deflector rods arranged inside the shell, and a distribution ring is arranged at the process gas inlet.
  • the number of the molten salt coolers is not less than one, and they are arranged in series and connected to the ultra-high pressure steam drum respectively.
  • the molten salt regulating valve is connected to at least two of the molten salt coolers, both of which are connected through a cold salt channel and a hot salt channel.
  • the molten salt cooler is connected to the oxidation reactor through a reactor salt channel.
  • the molten salt cooler is provided with a second boiler water inlet and a steam-water mixture outlet.
  • a supporting beam is provided between the molten salt cooler and the oxidation reactor.
  • a device for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device wherein the installation height of the ultra-high-pressure steam drum is 10m to 25m higher than the installation height of the molten salt cooler.
  • a method for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device comprising the following contents:
  • Boiler water pressure boosting step Boiler water flowing out of the switching cooler is boosted by a boiler water booster pump to a pressure sufficient to enter the ultra-high pressure steam drum;
  • High temperature process gas heat recovery step the pressurized boiler water is fed into the gas cooler and heated by the high temperature process gas at the outlet of the oxidation reactor;
  • Step of generating high-pressure or ultra-high-pressure steam the heated boiler water enters the ultra-high-pressure steam drum and then enters the molten salt cooler.
  • the generated high-pressure or ultra-high-pressure steam is separated from the liquid phase in the drum and then flows out.
  • the boiler feed water temperature entering the switch cooler is ⁇ 125°C
  • the boiler feed water pressure entering the switch cooler is ⁇ 4MPa
  • the temperature of the process gas entering the switch cooler is 240°C to 300°C.
  • the boiler water enters a boiler water buffer tank or a high-pressure deaerator before being pressurized by a pump, and the operating pressure entering the boiler water buffer tank is ⁇ 3MPag, and the operating pressure entering the high-pressure deaerator is 0.3MPag to 2.0MPag.
  • one oxidation reactor is provided with multiple molten salt coolers, which divide the total reaction heat into multiple parts, reduce the heat exchange load of a single molten salt cooler, and enable the heat exchange area of the molten salt cooler to meet the demand for producing high-pressure or ultra-high-pressure steam, thereby greatly reducing the manufacturing difficulty and risk of the molten salt cooler.
  • the production method of the present invention can significantly increase the by-product steam pressure of the maleic anhydride device, up to 15.6MPag, greatly reduce the energy consumption of the device, and have high economic efficiency.
  • Figure 1 is a flow chart of the oxidation unit of the n-butane process maleic anhydride device of the present invention
  • FIG2 is a top view of the arrangement of the molten salt cooler and the molten salt regulating valve of the present invention
  • Figure 3 is a schematic diagram of the structure of the gas cooler of the present invention.
  • S1-S9 are logistics numbers; 1, oxidation reactor; 2, molten salt pump; 3, molten salt regulating valve; 4, molten salt cooler; 5, gas cooler; 6, switching cooler; 7, ultra-high pressure steam drum; 8, boiler water buffer tank; 9, boiler water booster pump; 10, reactor salt channel; 11, support beam; 12, second boiler water inlet; 13, steam-water mixture outlet; 14, cold salt salt channel; 15, hot salt salt channel; 16, molten salt regulating valve stem; 17, molten salt regulating valve core; 18, process gas inlet; 19, process gas outlet; 20, inlet distribution ring; 21, U-shaped tube bundle; 22, deflector rod; 23, first boiler water inlet; 24, first boiler Boiler water outlet; 25. Pipe box partition.
  • the object of the present invention is to provide a device for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device and a production method thereof, so as to reduce the difficulty and production cost of producing high-pressure or ultra-high-pressure steam.
  • a device for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device includes an ultra-high-pressure steam drum 7 and a first path and a second path respectively connected in parallel with the ultra-high-pressure steam drum 7, wherein the first path includes a molten salt pump 2, an oxidation reactor 1, a regulating valve and a molten salt cooler 4 connected in sequence, and the second path includes a switching cooler 6 and a gas cooler 5 connected in sequence, and a boiler water buffer device and a boiler water booster pump 9 are arranged and connected between the switching cooler 6 and the gas cooler 5 in sequence.
  • the boiler water buffer device is a boiler water buffer tank 8 or a high-pressure deaerator.
  • the gas cooler 5 includes a first shell, a first boiler water inlet and a first boiler water outlet arranged on the top of the first shell, a process gas outlet arranged at the bottom of the first shell, a process gas inlet 18 arranged on the side of the first shell, and a plurality of U-shaped tube bundles and deflection rods arranged inside the shell, and a distribution ring is arranged at the process gas inlet 18;
  • the first shell is a shell and tube structure, arranged vertically, the boiler water enters the tube side U-shaped tube bundle from the first boiler water inlet, flows out from the boiler water outlet after being heated, and enters the ultra-high pressure steam drum 7, while the process gas enters the branch distribution ring from the shell side process gas inlet, enters the U-shaped tube bundle after distribution, and then flows downward along the U-shaped tube bundle.
  • the number of molten salt coolers 4 is not less than 1, and they are arranged in series in sequence. They are respectively connected to the ultra-high pressure steam drum 7.
  • the molten salt regulating valve 3 is connected to at least two of the molten salt coolers 4, all of which are connected through the cold salt channel 14 and the hot salt channel 15.
  • the molten salt cooler 4 is connected to the oxidation reactor 1 through the reactor salt channel 10.
  • the molten salt cooler 4 is provided with a second boiler water inlet 12 and a steam-water mixture outlet 13; the hot molten salt passes through the molten salt regulating valve 3 valve core to control the flow rate, enters the molten salt cooler 4 through the hot salt channel, flows out of the molten salt cooler 4 after cooling, enters the cold salt channel, and then returns to the reactor salt channel 10, while the high-pressure boiler water enters the tube side inlet of the molten salt cooler 4, and after being heated and vaporized, the steam-water mixture is discharged from the tube side outlet and enters the steam drum.
  • a support beam 11 is provided between the molten salt cooler 4 and the oxidation reactor 1 .
  • the installation height of the ultra-high pressure steam drum 7 is 10m to 25m higher than the installation height of the molten salt cooler 4 .
  • a method for producing high-pressure or ultra-high-pressure steam as a by-product of a maleic anhydride device comprising the following contents:
  • Boiler water pressure boosting step The boiler water flowing out of the switching cooler 6 is boosted by the boiler water booster pump 9 to a pressure sufficient to enter the ultra-high pressure steam drum 7;
  • High-temperature process gas heat recovery step the pressurized boiler water is fed into the gas cooler 5 and heated by the high-temperature process gas at the outlet of the oxidation reactor 1;
  • Step of generating high-pressure or ultra-high-pressure steam the heated boiler water enters the ultra-high-pressure steam drum 7 and then enters the molten salt cooler 4.
  • the generated high-pressure or ultra-high-pressure steam is separated from the liquid phase in the drum 7 and then flows out.
  • step a) the temperature of boiler feed water entering the switching cooler 6 is ⁇ 125°C, and the pressure of boiler feed water entering the switching cooler is ⁇ 4MPa; the temperature of process gas entering the switching cooler is 240°C to 300°C; further, the shell side of the switching cooler 6 adopts a lower pressure design, with an operating pressure of 2MPag and a design pressure of 2.5MPag, which further simplifies the design of the expansion joint and reduces equipment investment.
  • step b) the boiler water enters the boiler water buffer tank 8 or the high pressure boiler water buffer tank 8 before being pumped to increase the pressure.
  • the operating pressure entering the boiler water buffer tank 8 is ⁇ 3MPag
  • the operating pressure entering the high-pressure deaerator is 0.3MPag to 2.0MPag.
  • the boiler water booster pump 9 is a centrifugal pump, and the driving machine of the centrifugal pump can be an electric motor or a steam turbine.
  • step c) the pressurized boiler feed water enters the tube side of the gas cooler 5 .
  • step c) the temperature of the heated boiler water is ⁇ 240°C.
  • step c) the temperature of the heated boiler water is ⁇ 280°C.
  • step d the operating pressure of the steam drum is ⁇ 15.6 MPag.
  • step d the operating pressure of the steam drum is ⁇ 5.5 MPag.
  • step d the operating pressure of the steam drum is ⁇ 7.0 MPag.
  • Embodiment 1 is a diagrammatic representation of Embodiment 1:
  • a tubular fixed bed reactor is used, the feed rate of n-butane is 8840 kg/h (purity is 98 mol%), the concentration of n-butane in the gas S1 entering the oxidation reactor 1 is 1.85 mol%, the reaction temperature is 420°C, the conversion rate of n-butane is 85%, the weight yield of maleic anhydride at the reactor outlet is 98 wt% (8.55 t/h), the heat released is withdrawn by the shell side molten salt, and sent to the molten salt cooler to produce 15.6 MPag steam. There are two molten salt coolers. The temperature of the process gas S2 after the reaction is 420°C.
  • the gas In addition to containing ⁇ 1 mol% of the reaction product maleic anhydride, the gas also contains O2 , N2 , CO, CO2 , H2O and other components, as well as dust blown off from the catalyst bed and high freezing point tar generated in the reaction.
  • the process gas after the reaction is heat exchanged with boiler feed water to recover heat.
  • the boiler feed water S5 entering the switching cooler 6 is treated, and the oxygen content in the boiler feed water is required to be ⁇ 7 ⁇ g/L.
  • a high-pressure or medium-pressure thermal deaerator can be used to meet this requirement.
  • indicators such as hydrogen conductivity (25°C), hardness, iron, copper, sodium, silicon dioxide, chloride ions, TOCi, etc. must also meet the requirements of GBT12145-2016. Since the temperature of the boiler feed water flowing out of the deaerator is relatively high, generally 133-158°C, it is impossible to use this water to cool the reaction process gas to 130°C.
  • the boiler feed water needs to be temperature-adjusted to adjust the heat transfer temperature difference of the switching cooler 6 to adapt to the operating condition changes of the entire operation cycle. Therefore, the boiler feed water needs to be cooled and temperature-adjusted before entering the switching cooler 6.
  • the boiler feed water temperature entering the switch cooler 6 is 105 (scaling state) to 120 (clean state)° C., and the heat during temperature adjustment can be used to generate low-pressure steam or hot water.
  • the low-temperature and low-pressure boiler feed water S5 (temperature 105-120°C, pressure 2.2Mpag) that has been treated and temperature-adjusted enters the shell side of the switching cooler 6, cooling the reacted process gas S3 from 275°C to 130°C (S4), while the boiler feed water is heated to 195-209°C (S6, corresponding to the inlet water temperature).
  • the heated boiler water enters the boiler water buffer tank, and the operating pressure of the boiler water buffer tank is 1.5MPag (this pressure takes into account that when the switching cooler 6 is in the final scaling state, the lower boiler water temperature enters the boiler water buffer tank, and the operating pressure can still be maintained).
  • the higher temperature boiler feed water S6 enters the boiler water buffer tank and a small amount of flash evaporation will occur.
  • the flashed 1.5MPag steam enters the 1.5MPag steam network, and the pressure control valve is no longer set on the pipeline.
  • the saturated water of 1.5MPag and 201°C in the boiler water buffer tank is boosted to 16.2MPa by the boiler water booster pump and then sent to the pipe side of the gas cooler 5.
  • the high-pressure boiler feed water S7 exchanges heat with the process gas S2 at the reactor outlet in the gas cooler 5.
  • the reaction process gas S2 passes through the shell side of the gas cooler 5, and its temperature drops from 420°C to 275°C (S3).
  • the high-pressure boiler feed water S7 passes through the tube side of the gas cooler 5, and its temperature rises from 205°C (the work of the pump causes the boiler water to rise in temperature) to 291°C (S8), and then enters the ultra-high-pressure steam drum 7.
  • the operating pressure of the ultra-high pressure steam drum 7 is 15.6MPag, and the operating temperature is the saturation temperature of 346°C under the corresponding pressure.
  • the ultra-high pressure steam drum is usually set at a higher position. In this embodiment, the ultra-high pressure steam drum 7 is 20m higher than the molten salt cooler.
  • the boiler water in the ultra-high pressure steam drum enters the molten salt cooler, is heated by the 420°C hot molten salt to form a steam-water mixture, and then returns to the ultra-high pressure steam drum 7.
  • the by-product ultra-high pressure steam (pressure 15.6MPag, flow rate 94.1t/h) flows out from the drum outlet.
  • 11.0t15.6MPag ultra-high pressure steam is produced as a by-product.
  • the hot molten salt passes through the molten salt regulating valve core to control the flow rate, enters the molten salt cooler 5 through the hot salt salt channel 10, flows out of the molten salt cooler after cooling, enters the cold salt salt channel, and then returns to the reactor salt channel 2, while the high-pressure boiler water enters the tube side inlet of the molten salt cooler, and after being heated and vaporized, the steam-water mixture is discharged from the tube side outlet and enters the steam drum.
  • Embodiment 2 is a diagrammatic representation of Embodiment 1:
  • the boiler water buffer tank is replaced with a high-pressure deaerator.
  • the operating pressure of the high-pressure deaerator is 1.0 MPag.
  • the hot water entering the switching cooler is boiler feed water at 90-105°C.
  • Other conditions are the same as in Example 1.
  • the logistics data table is shown in Table 2.

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Abstract

本发明公开一种顺酐装置副产高压或超高压蒸汽的装置及其生产方法，包括超高压蒸汽汽包、连通的熔盐泵、氧化反应器、调节阀和熔盐冷却器，连通的切换冷却器和气体冷却器，切换冷却器和气体冷却器之间设置有锅炉水缓冲装置和锅炉水升压泵；本发明中锅炉水中间升压和气体冷却器的独特设计使得气体冷却器和切换冷却器十分易于制造，在避免工艺气体中的粉尘积聚和易于清洗粘附焦油的情况下仍然能够有效回收工艺气体的热量，用于多产高压或超高压蒸汽，同时一台氧化反应器设置多台熔盐冷却器，将总的反应热分成多个部分，减小单台熔盐冷却器的换热负荷，使熔盐冷却器的换热面积能够满足产高压或超高压蒸汽时的需求，降低熔盐冷却器的制造难度和风险。

Description

一种顺酐装置副产高压或超高压蒸汽的装置及其生产方法 技术领域
本发明涉及顺酐生产技术领域，特别是涉及一种顺酐装置副产高压或超高压蒸汽的装置及其生产方法。
背景技术
顺丁烯二酸酐简称顺酐，又名马来酸酐，是一种重要的有机化工原料，是仅次于苯酐和醋酐的世界第三大有机酸酐，广泛用于石油化工、食品加工、医药、建材等行业。最近几年，由于可降解塑料的大力发展，市场对可降解塑料的重要原料——1,4-丁二醇(BDO)的需求呈井喷式增加，这也带动了上游顺酐的产量需求。
目前，按原料路线，顺酐的生产方法可分为苯氧化法、正丁烷氧化法。传统的工艺以苯法氧化为主，但由于苯的制癌性和原料较贵，目前的新建装置均是正丁烷为原料。一个典型的正丁烷氧化制顺酐的装置基本包括反应单元和后处理单元。典型的反应单元流程如图6所示，正丁烷与空气进行催化氧化反应生成顺酐。正丁烷与空气的混合比例通常为1.5～2.1mol％，反应采用V/P体系催化剂，反应温度为400～430℃，反应器热点温度通常在420～480℃。反应器采用列管式固定床反应器，反应热由反应管外的循环熔盐撤出，以控制氧化反应的温度。反应管外被加热的熔盐进入熔盐冷却器，热熔盐将熔盐冷却器中的水汽化，产生饱和蒸汽，最终氧化反应器的反应热以蒸汽的形式产出。而从反应器出口气体温度约在390～435℃，经反应气体冷却器(气体冷却器)和切换冷却器(切换冷却器)冷却到130～160℃后，进入顺酐后处理单元。在后处理单元中，反应气体中的顺酐被吸收后进入解吸塔解吸得到粗制顺酐，经过精制后得到顺酐产品。
在孙丽丽主编的最新书籍《轻烃加工工艺与工程》(孙丽丽.中国石化出版社，2020)中系统介绍了正丁烷氧化生产顺酐技术的主要工艺和工程情况， 并介绍了Huntsman、ALMA、Conser的典型工艺流程，但均没有详细说明副产蒸汽的方法和细节，但在第601～604页中介绍了目前的正丁烷法顺酐装置副产蒸汽的典型操作参数：操作压力为4.1～4.3MPag，副产蒸汽量为7～8t/t顺酐(除去自用的～3t/t顺酐)。
一直以来，由于顺酐的生产规模较小(以5万吨/年生产装置为主)，因而对顺酐副产蒸汽的利用并不十分重视，但随着可降解塑料的快速发展，拉动了上游1,4-丁二醇和顺酐需求的迅速增加，现在上马的顺酐装置的典型规模达到20万吨/年，最大单套规模达到60万吨/年，单台在建反应器的生产规模也达到6.7万吨/年。以较小的典型规模20万吨/年正丁烷法顺酐装置为例，反应单元每小时副产蒸汽量将达到200～220万吨/年，这一规模比主产品顺酐的生产规模大出10～11倍，其经济效率在市场某些时候甚至与主产品顺酐持平或更优，因而，最大化的利用顺酐装置的反应热，最大化副产出更高品位、更具有经济效益的蒸汽，对于提高顺酐装置的经济性意义重大。
可惜的是，目前已经投产的正丁烷法顺酐装置均以副产4.0～5.5MPag蒸汽为主，但这对于利用正丁烷氧化的反应热是不充分且低效的。主要原因是，正丁烷氧化反应的典型反应温度为400～430℃，进入熔盐冷却器的热熔盐温度也维持在400～430℃，而4.0～5.5MPag的水蒸汽饱和温度为252～265℃，冷热侧的传热温差高达135～178℃，这在能耗的梯级利用上极不合理的。尽管惠州宇新化工有限责任公司最近在其新投产的顺酐装置上尝试副产更高压力的蒸汽(～8MPag)取得成功，但从合理设置传热温差、有效利用反应热角度来说，仍然有很大改进空间。
在工程上，按照初次投资、可操作性和运行费用的平衡，对于液体/蒸发传热体系，将操作温差控制在10～20℃是合理的，因此，按热侧熔盐400～430℃的操作温度，被加热侧物流最高可以被加热到≥380℃，如果被加热侧物流是水，则正丁烷氧化单元最大可以产生22MPag的亚临界或超临界蒸汽。通常，可以将6～12MPag的蒸汽称为高压蒸汽，12～16MPag的蒸汽称为超高压蒸汽，>17MPag的蒸汽可称为亚临界或超临界蒸汽。
尽管从传热温差的角度考虑，正丁烷法顺酐装置可以产生高达22MPag的蒸汽，但正丁烷法顺酐装置毕竟以生产顺酐为主要目的，副产蒸汽为次要目的，因而，除了要考虑传热温差外，还应该考虑装置的可操作性，以确保正丁烷法顺酐装置的稳定可靠运行，所以，一般来说，将操作的传热温差放得更宽(30～40℃)从工艺角度看是可行且经济的。另外，考虑到催化剂的初期高活性和低操作温度(～390℃)，在保证正丁烷氧化制顺酐装置正常生产时，正丁烷法顺酐反应单元最高副产～350℃、16.5Mpa的超高压蒸汽是可能的，不过考虑到更高的产汽压力和温度对锅炉水水质的要求更高，按照GB12145-2016的要求，正丁烷法顺酐装置蒸汽的最高压力确定在15.6MPag是比较合适的。
上面的论述说明了正丁烷法顺酐装置副产超高压蒸汽的可行性，不过要实现这一点并不简单，要说明这一问题，有必要对正丁烷法氧化反应出口气体的流程和传统方法进一步说明。
目前的正丁烷法顺酐装置的氧化反应均采用V/P体系的催化剂，这种催化剂能够使正丁烷高选择性的生成顺酐，但显著的缺点是强度较差，在正常生产时会有粉尘被吹出，同时在反应器出口还伴有少量高凝固点的焦油，因而，为了避免这些粉尘和焦油在设备内积聚，传统方案中，反应后的工艺气体冷却分成两级，即一级冷却器(也称为气体冷却器)和二级冷却器(也称为切换冷却器)，而工艺气体均在冷却器的管程换热，一级冷却器是为了减小死区，防止催化剂粉尘在设备内积聚，而二级冷却器需要定时切换清洗(由于高凝固点的焦油在冷却过程中会析出并粘附在换热管内壁，造成传热效果快速变差)，因而为了清洗方便，工艺气也设计在管程。而一级冷却器和二级冷却器的壳程则用于预热锅炉给水和产生4～5.5MPag的蒸汽。这种设计是合理的，并且在现有运行的装置中得到验证。
如果想用传统的方法直接产生高压或超高压蒸汽是困难的，这并不只是提高操作压力和设计压力即能完成的，尽管惠州宇新在新建的正丁烷法顺酐装置上实现了采用传统工艺中副产～8MPag蒸汽，但仍然存在一些有待改进的问题， 并且当想要再提高单台设备生产规模或副产蒸汽压力时，传统方法将变成不再适合。
其主要的问题如下：
气体冷却器和切换冷却器采用固定管板结构，工艺气均走管程，以防止堵或易于清理，但这也带来了新问题。由于气体冷却器和切换冷却器均为固定管板结构，而气体冷却器和切换冷却器的管壳程温差较大，且工况变化，因而设备壳侧均需要设置膨胀节吸收由于管壳程温度不同而造成膨胀量差异，以避免应力过大造成对设备的破坏，这在传统副产4～5.5MPag中压蒸汽时是可行的，但如果要产更高压力的蒸汽时，壳程的操作和设计压力上升，将造成壳程膨胀节的设计和制造困难，难于工程实施，即使勉强实现，也将显著提高装置投资和设备风险。
由于副产蒸汽的压力升高，熔盐冷却器的管壳程温差相比于副产4～5.5MPag的蒸汽时的温差要小许多，因而所需要的设备换热面积也将大得多，这意味着熔盐冷却器的直径和长度均需要增加，但对于高压设备来说，设备直径的增加将导致投资的快速增加，并且设备直径也不能无限增大，盲目的增大设备除导致设备投资大幅增加外，还将造成制造困难，无法实施。
为了解决上述问题，本发明提供一种顺酐装置副产高压或超高压蒸汽的装置及其生产方法，来解决以往的设备生产高压或超高压蒸汽困难且成本较高的问题。
发明内容
本发明的目的是提供一种顺酐装置副产高压或超高压蒸汽的装置及其生产方法，达到降低生产高压或超高压蒸汽困难性以及生产成本的目的。
为实现上述目的，本发明提供了如下方案：
一种顺酐装置副产高压或超高压蒸汽的装置，包括超高压蒸汽汽包以及分别与所述超高压蒸汽汽包并联的第一路径和第二路径，所述第一路径包括依次连通的熔盐泵、氧化反应器、调节阀和熔盐冷却器，所述第二路径包括依次连 通的切换冷却器和气体冷却器，所述切换冷却器和气体冷却器之间依次设置并连通有锅炉水缓冲装置和锅炉水升压泵。
优选地，所述锅炉水缓冲装置为锅炉水缓冲罐或高压除氧器。
优选地，所述气体冷却器包括第一壳体、设置在所述第一壳体顶部的第一锅炉水进口和第一锅炉水出口、设置在所述第一壳体底部的工艺气体出口、设置在所述第一壳体侧部的工艺气体进口以及设置在所述壳体内部的若干U型管束和折流杆，所述工艺气体的进口处设置有分布环。
优选地，所述熔盐冷却器的设置数量不少于1台，且依次串联设置并分别与所述超高压蒸汽汽包连通。
优选地，所述熔盐调节阀与至少2台所述熔盐冷却器连通，均通过冷盐盐道和热盐盐道连通，所述熔盐冷却器通过反应器盐道与所述氧化反应器连通，所述熔盐冷却器上设置有第二锅炉水进口和汽水混合物出口。
优选地，所述熔盐冷却器和所述氧化反应器之间设置有支持梁。
一种顺酐装置副产高压或超高压蒸汽的装置，所述超高压蒸汽汽包的安装高度比所述熔盐冷却器的安装高度高10m至25m。
一种顺酐装置副产高压或超高压蒸汽的方法，包括以下内容：
a)低温工艺气体热量回收步骤：锅炉给水经过切换冷却器的壳程，被管程的低温反应后工艺气体加热；
b)锅炉水升压步骤：将从切换冷却器中流出的锅炉水用锅炉水升压泵升压至足以进入超高压蒸汽汽包中；
c)高温工艺气体热量回收步骤：被加压的锅炉水送入气体冷却器并被氧化反应器出口的高温工艺气体加热；
d)发生高压或超高压蒸汽步骤：被加热的锅炉水进入到超高压蒸汽汽包，然后进入熔盐冷却器，产生的高压或超高压蒸汽在汽包中与液相分离后流出。
优选地，在步骤a)中，进入切换冷却器的锅炉给水温度≤125℃，进入切换冷却器的锅炉给水的压力≤4MPa；进入所述切换冷却器的工艺气体的温度 为240℃至300℃。
优选地，在步骤b)中，锅炉水被泵升压前先进入锅炉水缓冲罐或高压除氧器，进入锅炉水缓冲罐的操作压力≤3MPag，进入高压除氧器的操作压力为0.3MPag至2.0MPag。
本发明相对于现有技术取得了以下技术效果：
1.本发明中锅炉水中间升压和气体冷却器的独特设计巧妙避开了设备设计难题，使得气体冷却器和切换冷却器十分易于制造，在避免工艺气体中的粉尘积聚和易于清洗粘附焦油的情况下仍然能够有效回收工艺气体的热量，用于多产高压或超高压蒸汽。
2.本发明中1台氧化反应器设置多台熔盐冷却器，将总的反应热分成多个部分，减小单台熔盐冷却器的换热负荷，使熔盐冷却器的换热面积能够满足产高压或超高压蒸汽时的需求，大幅降低熔盐冷却器的制造难度和风险。
3.本发明的生产方法能够显著提高顺酐装置的副产蒸汽压力，最高达15.6MPag，装置的能耗大幅降低，经济效率高。
附图说明
为了更清楚地说明本发明或现有技术中的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
附图1为本发明正丁烷法顺酐装置氧化单元流程图；
附图2为本发明熔盐冷却器与熔盐调节阀的布置俯视图；
附图3为本发明气体冷却器结构示意图；
其中，S1-S9为物流号；1、氧化反应器；2、熔盐泵；3、熔盐调节阀；4、熔盐冷却器；5、气体冷却器；6、切换冷却器；7、超高压蒸汽汽包；8、锅炉水缓冲罐；9、锅炉水升压泵；10、反应器盐道；11、支持梁；12、第二锅炉水进口；13、汽水混合物出口；14、冷盐盐道；15、热盐盐道；16、熔盐调节阀阀杆；17、熔盐调节阀阀芯；18、工艺气体进口；19、工艺气体出口；20、进口分布环；21、U形管束；22、折流杆；23、第一锅炉水进口；24、第一锅 炉水出口；25、管箱隔板。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明的目的是提供一种顺酐装置副产高压或超高压蒸汽的装置及其生产方法，达到降低生产高压或超高压蒸汽困难性以及生产成本的目的。
为使本发明的上述目的、特征和优点能够更加明显易懂，下面结合附图和具体实施方式对本发明作进一步详细的说明。
参考图1，一种顺酐装置副产高压或超高压蒸汽的装置，包括超高压蒸汽汽包7以及分别与所述超高压蒸汽汽包7并联的第一路径和第二路径，所述第一路径包括依次连通的熔盐泵2、氧化反应器1、调节阀和熔盐冷却器4，所述第二路径包括依次连通的切换冷却器6和气体冷却器5，所述切换冷却器6和气体冷却器5之间依次设置并连通有锅炉水缓冲装置和锅炉水升压泵9。
进一步的，锅炉水缓冲装置为锅炉水缓冲罐8或高压除氧器。
参考图3，所述气体冷却器5包括第一壳体、设置在所述第一壳体顶部的第一锅炉水进口和第一锅炉水出口、设置在所述第一壳体底部的工艺气体出口、设置在所述第一壳体侧部的工艺气体进口18以及设置在所述壳体内部的若干U型管束和折流杆，所述工艺气体进口18处设置有分布环；进一步的，第一壳体为管壳式结构，立式布置，锅炉水从第一锅炉水进口进入管侧U形管束，被加热后从锅炉水出口流出，进入超高压蒸汽汽包7，而工艺气体从壳侧工艺气体进口进入分口分布环，经过分布后进入U形管束，然后沿U形管束往下流动，由于管束间仅设有折流杆，没有死区点，因而工艺气体中的粉尘也随之往下流动，不在设备内积聚，最终，冷却后的带有粉尘的工艺气体从设于设备底部的工艺气体出口流出，进入切换冷却器6。
参考图2，所述熔盐冷却器4的设置数量不少于1台，且依次串联设置并 分别与所述超高压蒸汽汽包7连通。
参考图2，熔盐调节阀3与至少2台所述熔盐冷却器4连通，均通过冷盐盐道14和热盐盐道15连通，所述熔盐冷却器4通过反应器盐道10与所述氧化反应器1连通，所述熔盐冷却器4上设置有第二锅炉水进口12和汽水混合物出口13；热熔盐经过熔盐调节阀3阀芯控制流量，经过热盐盐道进入熔盐冷却器4，经过冷却后流出熔盐冷却器4进入冷盐盐道后返回反应器盐道10，而高压锅炉水进入熔盐冷却器4的管侧进口，经过加热汽化后，汽水混合物从管侧出口排出，进入汽包。
参考图2，所述熔盐冷却器4和所述氧化反应器1之间设置有支持梁11。
进一步的，超高压蒸汽汽包7的安装高度比所述熔盐冷却器4的安装高度高10m至25m。
一种顺酐装置副产高压或超高压蒸汽的方法，包括以下内容：
a)低温工艺气体热量回收步骤：锅炉给水经过切换冷却器6的壳程，被管程的低温反应后工艺气体加热；
b)锅炉水升压步骤：将从切换冷却器6中流出的锅炉水用锅炉水升压泵9升压至足以进入超高压蒸汽汽包7中；
c)高温工艺气体热量回收步骤：被加压的锅炉水送入气体冷却器5并被氧化反应器1出口的高温工艺气体加热；
d)发生高压或超高压蒸汽步骤：被加热的锅炉水进入到超高压蒸汽汽包7，然后进入熔盐冷却器4，产生的高压或超高压蒸汽在汽包7中与液相分离后流出。
进一步的，在步骤a)中，进入切换冷却器6的锅炉给水温度≤125℃，进入切换冷却器的锅炉给水的压力≤4MPa；进入所述切换冷却器的工艺气体的温度为240℃至300℃；进一步的，切换冷却器6的壳程采用较低的压力设计，操作压力为2MPag，设计压力为2.5MPag，更加简化了膨胀节的设计，并降低了设备投资。
进一步的，在步骤b)中，锅炉水被泵升压前先进入锅炉水缓冲罐8或高 压除氧器，进入锅炉水缓冲罐8的操作压力≤3MPag，进入高压除氧器的操作压力为0.3MPag至2.0MPag。
进一步的，锅炉水升压泵9采用离心泵，离心泵的驱动机可以采用电机或汽轮机。
进一步的，步骤c)中，升压后的锅炉给水进入气体冷却器5的管程。
进一步的，步骤c)中，加热后的锅炉水温度≥240℃。
进一步的，步骤c)中，加热后的锅炉水温度≥280℃。
进一步的，步骤d)中，汽包的操作压力≤15.6MPag。
进一步的，步骤d)中，汽包的操作压力≥5.5MPag。
进一步的，步骤d)中，汽包的操作压力≥7.0MPag。
实施例1：
以单条生产线规模为6.7万吨/年顺酐的反应单元为例进行说明：
采用1台列管式固定床反应器，正丁烷投料量为8840kg/h(纯度为98mol％)，进入氧化反应器1的气体S1中正丁烷浓度为1.85mol％，反应温度为420℃，正丁烷的转化率为85％，反应器出口的顺酐重量收率为98wt％(8.55t/h)，放出的热量由壳侧熔盐撤出，送入熔盐冷却器产15.6MPag蒸汽，熔盐冷却器设有2台。反应后的工艺气体S2的温度为420℃，气体中除含有～1mol％的反应产物顺酐，还含有O2、N2、CO、CO2、H2O等组分，同时还包括从催化剂床层吹落的粉尘、反应中生成的高凝固点的焦油。将反应后的工艺气体与锅炉给水换热，回收热量。
进入切换冷却器6的锅炉给水S5是经过处理的，要求锅炉给水中的氧含量≤7μg/L，可以采用高压或中压热力除氧器来达到这一要求。另外，氢电导率(25℃)、硬度、铁、铜、钠、二氧化硅、氯离子、TOCi等指标也必须满足GBT12145-2016的要求。由于锅炉给水从除氧器流出时的温度较高，一般为133～158℃，用这股水来将反应工艺气体冷却至130℃是无法做到的。另外，由于切换冷却器6的初末期工况变化(因焦油析出而造成传热效果变差)，需要对锅炉给水进行调温，以调整切换冷却器6的传热温差以适应整个操作周期的工况变化，因此，在锅炉给水进入切换冷却器6前需要先进行冷却调温。 在本实施例中，进入切换冷却器6的锅炉给水温度为105(结垢状态)～120(清洁状态)℃，调温时的热量可以用来产生低压蒸汽或热水。
经过水质处理并且调温后的低温低压的锅炉给水S5(温度105～120℃、压力2.2Mpag)进入切换冷却器6的壳程，将反应后的工艺气体S3从275℃冷却至130℃(S4)，而锅炉给水则被升温至195～209℃(S6，与进水温度对应)。
被加热后的锅炉水进入锅炉水缓冲罐，锅炉水缓冲罐的操作压力为1.5MPag(这一压力考虑了切换冷却器6处于末期结垢状态时，较低的锅炉水温度进入锅炉水缓冲罐时，仍然能够维持操作压力)，当切换冷却器6处于清洁状态时，较高温度的锅炉给水S6进入锅炉水缓冲罐将发生少量闪蒸，闪蒸出的1.5MPag蒸汽进入1.5MPag蒸汽管网，管线上不再设置压控阀。锅炉水缓冲罐中1.5MPag、201℃的饱和水经过锅炉水升压泵升压至16.2MPa后，送入气体冷却器5的管程。
高压锅炉给水S7在气体冷却器5中与反应器出口的工艺气体S2换热，反应工艺气体S2经过气体冷却器5的壳程，温度从420℃降温至275℃(S3)，而高压锅炉给水S7经过气体冷却器5的管程，温度从205℃(泵的做功使锅炉水有温升)升温至291℃(S8)，然后进入超高压蒸汽汽包7。
超高压蒸汽汽包7的操作压力为15.6MPag，操作温度为对应压力下的饱和温度346℃。由于副产蒸汽的压力升高，蒸汽密度也增大，而锅炉水随着温度的升高，密度反而降低，因而蒸汽与锅炉水的密度差相比于传统的副产4.0～5.5MPag蒸汽工艺要小许多，所以，超高压蒸汽汽包通常设置在较高的位置，本实施例中超高压蒸汽汽包7比熔盐冷却器高20m。超高压蒸汽汽包中的锅炉水进入熔盐冷却器，被420℃的热熔盐加热后形成汽水混合物再返回超高压蒸汽汽包7，汽液分离后，副产的超高压蒸汽(压力15.6MPag、流量为94.1t/h)从汽包出口流出。平均每生产1t顺酐，副产11.0t15.6MPag的超高压蒸汽。
图3中，热熔盐经过熔盐调节阀阀芯控制流量，经过热盐盐道10进入熔盐冷却器5，经过冷却后流出熔盐冷却器进入冷盐盐道后返回反应器盐道2，而高压锅炉水进入熔盐冷却器的管侧进口，经过加热汽化后，汽水混合物从管侧出口排出，进入汽包。
物流数据见表1。
表1
实施例2：
将锅炉水缓冲罐改为高压除氧器，高压除氧器的操作压力为1.0MPag，进入切换冷却器的热水为90～105℃的锅炉给水，其它条件与实施例1相同。
物流数据表见表2。
表2
根据实际需求而进行的适应性改变均在本发明的保护范围内。
需要说明的是，对于本领域技术人员而言，显然本发明不限于上述示范性实施例的细节，而且在不背离本发明的精神或基本特征的情况下，能够以其他的具体形式实现本发明。因此，无论从哪一点来看，均应将实施例看作是示范性的，而且是非限制性的，本发明的范围由所附权利要求而不是上述说明限定，因此旨在将落在权利要求的等同要件的含义和范围内的所有变化囊括在发明内。不应将权利要求中的任何附图标记视为限制所涉及的权利要求。

Claims (10)

  1. 一种顺酐装置副产高压或超高压蒸汽的装置，其特征在于，包括超高压蒸汽汽包以及分别与所述超高压蒸汽汽包并联的第一路径和第二路径，所述第一路径包括依次连通的熔盐泵、氧化反应器、调节阀和熔盐冷却器，所述第二路径包括依次连通的切换冷却器和气体冷却器，所述切换冷却器和气体冷却器之间依次设置并连通有锅炉水缓冲装置和锅炉水升压泵。
  2. 根据权利要求1所述的一种顺酐装置副产高压或超高压蒸汽的装置，其特征在于，所述锅炉水缓冲装置为锅炉水缓冲罐或高压除氧器。
  3. 根据权利要求1所述的一种顺酐装置副产高压或超高压蒸汽的装置，其特征在于，所述气体冷却器包括第一壳体、设置在所述第一壳体顶部的第一锅炉水进口和第一锅炉水出口、设置在所述第一壳体底部的工艺气体出口、设置在所述第一壳体侧部的工艺气体进口以及设置在所述壳体内部的若干U型管束和折流杆，所述工艺气体的进口处设置有分布环。
  4. 根据权利要求1所述的一种顺酐装置副产高压或超高压蒸汽的装置，其特征在于，所述熔盐冷却器的设置数量不少于1台，且依次串联设置并分别与所述超高压蒸汽汽包连通。
  5. 根据权利要求4所述的一种顺酐装置副产高压或超高压蒸汽的装置，其特征在于，所述熔盐调节阀与至少2台所述熔盐冷却器连通，均通过冷盐盐道和热盐盐道连通，所述熔盐冷却器通过反应器盐道与所述氧化反应器连通，所述熔盐冷却器上设置有第二锅炉水进口和汽水混合物出口。
  6. 根据权利要求5所述的一种顺酐装置副产高压或超高压蒸汽的装置，其特征在于，所述熔盐冷却器和所述氧化反应器之间设置有支持梁。
  7. 根据权利要1所述的一种顺酐装置副产高压或超高压蒸汽的装置，其特征在于，所述超高压蒸汽汽包的安装高度比所述熔盐冷却器的安装高度高10m至25m。
  8. 一种顺酐装置副产高压或超高压蒸汽的方法，其特征在于，包括以下内容：
    a)低温工艺气体热量回收步骤：锅炉给水经过切换冷却器的壳程，被管 程的低温反应后工艺气体加热；
    b)锅炉水升压步骤：将从切换冷却器中流出的锅炉水用锅炉水升压泵升压至足以进入超高压蒸汽汽包中；
    c)高温工艺气体热量回收步骤：被加压的锅炉水送入气体冷却器并被氧化反应器出口的高温工艺气体加热；
    d)发生高压或超高压蒸汽步骤：被加热的锅炉水进入到超高压蒸汽汽包，然后进入熔盐冷却器，产生的高压或超高压蒸汽在汽包中与液相分离后流出。
  9. 根据权利要求8所述的一种顺酐装置副产高压或超高压蒸汽的方法，其特征在于，在步骤a)中，进入切换冷却器的锅炉给水温度≤125℃，进入切换冷却器的锅炉给水的压力≤4MPa；进入所述切换冷却器的工艺气体的温度为240℃至300℃。
  10. 根据权利要求8所述的一种顺酐装置副产高压或超高压蒸汽的方法，其特征在于，在步骤b)中，锅炉水被泵升压前先进入锅炉水缓冲罐或高压除氧器，进入锅炉水缓冲罐的操作压力≤3MPag，进入高压除氧器的操作压力为0.3MPag至2.0MPag。
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