CN118059758A

CN118059758A - Cross-quasi-critical zone heating system

Info

Publication number: CN118059758A
Application number: CN202410409670.2A
Authority: CN
Inventors: 陈龙祥; 叶楷; 林锦新; 黄婷婷
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Fujian Institute of Research on the Structure of Matter of CAS
Priority date: 2024-04-07
Filing date: 2024-04-07
Publication date: 2024-05-24

Abstract

The invention discloses a cross-quasi-critical zone heating system, which belongs to the technical field of supercritical water oxidation and comprises a fourth flow guide pipe, a first-stage baffle plate and a heating kettle, wherein the first-stage baffle plate and the heating kettle form a first-stage mixing cavity, one end of the fourth flow guide pipe extends into the middle of the first-stage mixing cavity, a first flow guide hole is arranged at one end of the first-stage baffle plate, which is connected with the heating kettle, and the first-stage mixing cavity is communicated with the inner cavity of the heating kettle. The water at normal temperature is preheated to the temperature close to the critical area, the preheated water is sent into the middle part of the heating kettle through the fourth guide pipe, the water at lower temperature is surrounded by high-temperature water and is diffused after being quickly fused, the temperature of mixed cold and hot fluid is higher than the temperature of the critical area, the crossing of the critical area is realized, the water in the heating kettle close to the wall surface only passes through the critical area when the temperature is raised for the first time, and then the preheated water at lower temperature is mixed with external high-temperature water after entering the heating kettle, and an inclined temperature layer is formed on the near-wall surface, so that the water on the near-wall surface is kept at the temperature higher than the critical area.

Description

Cross-quasi-critical zone heating system

Technical Field

The invention relates to the technical field of supercritical water oxidation, in particular to a cross-pseudo-critical zone heating system.

Background

Supercritical water is a physical state above the critical temperature (374 ℃) and the critical pressure (22.1 MPa), and in the state, the water has unique physical and chemical properties, such as low viscosity, high diffusivity, adjustable solubility and can be used as a good solvent and a reaction medium, so that the supercritical water oxidation, supercritical water gasification, supercritical water liquefaction and other technologies can be formed, and the supercritical water has wide application potential in the fields of chemical industry, energy, environmental protection and the like.

An electric heater or a heat exchanger used in the existing supercritical water system is required to heat up working media such as water, raw materials, fuel and the like from a normal temperature region to a quasi-critical temperature region, and finally, the working media are heated to a target temperature (30 ℃ above the critical temperature). However, the water properties in the quasi-critical temperature region (342-402 ℃) are changed drastically, so that the water is more corrosive in the temperature region than the water in the temperature region or lower than the temperature region, the equipment materials are corroded severely, the service life of the equipment is shortened seriously, and the stable operation and safety of the equipment are affected.

In view of the above, the present inventors have conducted intensive studies on the above problems, and have produced the present invention.

Disclosure of Invention

The invention aims to provide a cross-critical zone heating system device, wherein an inclined temperature layer capable of crossing a critical zone is formed inside heating equipment through a high-low temperature fluid mixing temperature-rising strategy, so that the temperature crossing of the critical zone is realized under the condition that water/raw materials and other substances are not contacted with a metal wall surface, the equipment safety of a supercritical water system is ensured, and the service life of the equipment is prolonged.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

The cross-critical zone heating system comprises a fourth flow guide pipe and a heating kettle, wherein the heating kettle is a heating kettle with a cavity inside, a water inlet and a water outlet are arranged on the heating kettle, and the fourth flow guide pipe is connected with the water inlet and extends into the middle part of the inner cavity of the heating kettle;

The heating kettle comprises a water inlet, a heating kettle, a first-stage baffle plate, a second-stage baffle plate, a first-stage mixing cavity, a water inlet and a water outlet, wherein the water inlet is formed in the bottom of the heating kettle, one end of the fourth flow guide pipe stretches into the water inlet and is arranged in the first-stage mixing cavity, a plurality of first flow guide holes are formed in the first-stage baffle plate and the position of one end of the first-stage baffle plate, which is connected with the heating kettle, the first-stage mixing cavity is communicated with the inner cavity of the heating kettle through the first flow guide holes, and a heater for heating the heating kettle is arranged on the outer side wall of the heating kettle.

Preferably, the heating kettle further comprises a second-stage baffle plate, the second-stage baffle plate is arranged on the periphery of the first-stage baffle plate, a second-stage mixing cavity is formed by the inner wall of the second-stage baffle plate, the outer wall of the first-stage baffle plate and the bottom of the heating kettle, a third-stage mixing cavity is formed between the inner wall of the heating kettle and the outer wall of the second-stage baffle plate, the first-stage mixing cavity is communicated with the second-stage mixing cavity through the first diversion hole, a second diversion hole is formed at one end of the second-stage baffle plate, which is far away from the bottom of the heating kettle, and the second-stage mixing cavity is communicated with the third-stage mixing cavity through the second diversion hole.

Preferably, at least one of the primary baffles and at least one of the secondary baffles are arranged in a crossing manner, and a plurality of the primary baffles and a plurality of the secondary baffles are arranged.

Preferably, one end of the fourth flow guiding pipe, which is arranged in the primary mixing cavity, is provided with a plurality of third flow guiding holes, and the fourth flow guiding pipe is communicated with the primary mixing cavity through the third flow guiding holes.

Preferably, the primary baffle plate and the secondary baffle plate are corrosion-resistant baffle plates, and the heating kettle is a metal pressure-bearing heating kettle.

Preferably, the heater comprises a heating sleeve sleeved on the outer side wall of the heating kettle.

Preferably, a plurality of temperature measuring points are arranged on the heating kettle.

Preferably, the device further comprises a high-pressure pump and a preheater, wherein the fourth flow guide pipe is connected with the preheater, the preheater heats a normal-temperature medium to a preset temperature, the normal-temperature medium flows into the inner cavity of the heating kettle through the first-stage mixing cavity through the fourth flow guide pipe, the heater heats the heating kettle for the second time and exchanges heat with the medium, and the preset temperature is higher than the supercritical temperature of the reaction liquid in the inner cavity of the heating kettle.

Preferably, the reaction kettle further comprises a reaction kettle body, the reaction kettle comprises a pressure-bearing kettle body and a lining kettle body arranged in the pressure-bearing kettle body, the pressure-bearing kettle body and the lining kettle body are both closed kettle bodies, an annular gap is formed between the inner wall of the pressure-bearing kettle body and the outer wall of the lining kettle body, a closed high-pressure cavity is formed, a closed reaction cavity is formed in the inner cavity of the lining kettle body, a water-oxygen mixed fluid inlet and a non-corrosive gas inlet, a temperature-control water inlet and a kettle body outlet which are communicated with the high-pressure cavity and the outside are formed in the pressure-bearing kettle body, and the reaction cavity is communicated with the water-oxygen mixed fluid inlet through a honeycomb duct.

Preferably, the pressure-bearing kettle body comprises a first kettle body and a first kettle cover which are detachably connected, and the lining kettle body comprises a second kettle body and a second kettle cover which are detachably connected;

The honeycomb duct includes first honeycomb duct, second honeycomb duct and the third honeycomb duct that the head and the tail are linked together in proper order, first honeycomb duct sets up on the first cauldron body, the second honeycomb duct sets up first cauldron is covered, the third honeycomb duct sets up on the second cauldron is covered, first honeycomb duct keep away from the one end of second honeycomb duct with water oxygen mixed fluid entry is connected, the third honeycomb duct is kept away from the one end setting of second honeycomb duct is in the reaction chamber.

Preferably, the first flow guide pipe is an L-shaped pipe, the second flow guide pipe is a U-shaped pipe, the third flow guide pipe is a straight pipe, the first kettle cover is provided with a first through hole and a second through hole for the two ends of the second flow guide pipe to penetrate through, the second kettle cover is provided with a third through hole for the third flow guide pipe to penetrate through, the axis of the second through hole is coincident with the axis of the third through hole, one end of the second flow guide pipe penetrates through the first through hole and is communicated with the first flow guide pipe, the other end of the second flow guide pipe penetrates through the second through hole and is communicated with the third flow guide pipe, and the third flow guide pipe penetrates through the third through hole.

Preferably, the reaction kettles are at least one, the non-corrosive gas supply unit is connected with the non-corrosive gas inlets of the reaction kettles through pipelines and is communicated with the high-pressure cavity, the heating unit is connected with the water-oxygen mixed fluid inlets of the reaction kettles through pipelines and the oxygen supply unit after converging, and is communicated with the reaction cavity, the cooling water supply unit is connected with the temperature control water inlets of the reaction kettles through pipelines, and the energy recovery unit is connected with the kettle body outlets of the reaction kettles through pipelines.

By adopting the design scheme, the invention has the beneficial effects that: the inner wall of the heating kettle is separated by the first-stage baffle plate, so that the problem of corrosion of the heating kettle can be effectively solved, namely, the corrosion-resistant wall suffering from corrosion does not bear pressure, materials with good corrosion resistance can be selected, and the heating kettle is convenient to replace; the water at normal temperature is preheated to the temperature close to the critical area through the preheater, the water in the kettle is heated again in the heating kettle, the temperature of the water in the kettle is controlled by the temperature controller all the time after passing through the critical area only when the water is heated for the first time, the preheated water is sent into the middle part of the high-pressure kettle through the fourth guide pipe, the water at lower temperature is surrounded by the water, and is diffused after being quickly fused, and the mixed cold and hot fluid temperature is higher than the critical area temperature before the injected cold water reaches the inner wall of the heating kettle, so that the crossing of the critical area is realized.

Drawings

FIG. 1 is a schematic structural diagram of a reaction kettle in the invention;

FIG. 2 is an exploded view of the reactor of the present invention;

FIG. 3 is a schematic diagram of the present invention;

FIG. 4 is a schematic structural view of a heating kettle in the invention;

FIG. 5 is a schematic diagram of a heating unit of the present invention;

In the figure: the reaction kettle 1, the pressure-bearing kettle body 11, the first kettle body 111, the first kettle cover 112, the first through hole 113, the second through hole 114, the lining kettle body 12, the second kettle body 121, the second kettle cover 122, the third through hole 123, the high-pressure cavity 13, the reaction cavity 14, the flow guide 15, the first flow guide 151, the second flow guide 152, the third flow guide 153, the water-oxygen mixed fluid inlet 161, the non-corrosive gas inlet 162, the temperature-control water inlet 163, the kettle body outlet 164, the oxygen supply unit 2, the liquid oxygen storage tank 21, the liquid oxygen pump 22, the oxygen heat exchanger 23, the non-corrosive gas supply unit 3, the gas storage tank 31, the compressor unit 32, the cooling water supply unit 4, the first high-pressure water pump 41, the first heat exchanger 42, the heating unit 5, the second high-pressure water pump 51, the second heat exchanger 52, the fourth flow guide 53, the third flow guide 531, the heating kettle 54, the water inlet 541, the water outlet 542, the third mixing cavity 543, the first baffle plate 55, the first mixing cavity 551, the first baffle plate 552, the second baffle plate 561, the second mixing cavity 561, the second baffle plate 62, the second flow guide unit 62, the energy recovery unit 6, the expansion valve 61 and the expansion unit.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Referring to fig. 1 to 5:

A supercritical water self-propagating reaction system comprises a reaction kettle 1, an oxygen supply unit 2, a non-corrosive gas supply unit 3, a cooling water supply unit 4, a heating unit 5 and an energy recovery unit 6.

The reaction kettle 1 comprises a pressure-bearing kettle body 11 and a lining kettle body 12 arranged in the pressure-bearing kettle body 11, wherein the pressure-bearing kettle body 11 and the lining kettle body 12 are both closed kettle bodies, and the pressure-bearing kettle body and the lining kettle body 12 form a back-shaped structure. An annular gap is formed between the inner wall of the pressure-bearing kettle body 11 and the outer wall of the lining kettle body 12, a closed high-pressure cavity 13 is formed, and a closed reaction cavity 14 is formed in the inner cavity of the lining kettle body 12. Preferably, the lining kettle body 12 is a rigid lining kettle body 12, the rigid lining kettle body 12 is used for replacing the periphery of the fluid, the reaction area is effectively controlled within the fixed range of the reaction cavity 14, highly corrosive substances are prevented from directly contacting the pressure-bearing kettle body 11, and the service life of the pressure-bearing kettle body 11 is prolonged. The inner liner tank 12 is not required to be pressurized by the internal and external communication, and thus can be made into a thin-walled type and consumable part.

The pressure-bearing kettle body 11 is provided with a water-oxygen mixed fluid inlet 161, a non-corrosive gas inlet 162, a temperature-control water inlet 163 and a kettle body outlet 164 which are communicated with the high-pressure cavity 13 and the outside, and the reaction cavity 14 is communicated with the water-oxygen mixed fluid inlet 161 through a flow guide pipe 15. A high pressure non-corrosive gas (air or nitrogen, etc.) is introduced into the non-corrosive gas inlet 162 before the reaction, forming a high pressure environment, causing the supercritical water and oxygen mixture to enter the reaction chamber 14 and then rapidly reach the reaction conditions. The high pressure gas is interposed between the liner tank body 12 and the autoclave body 11 in the high pressure chamber 13, further reducing the chance of corrosive substances flowing into the autoclave body 11 to contact it. Compared with the traditional water environment, the high-pressure gas has low density and low specific heat, so the lower thermal inertia can improve the starting speed of the whole reaction.

Further, the pressure-bearing kettle body 11 comprises a first kettle body 111 and a first kettle cover 112 which are detachably connected, and the lining kettle body 12 comprises a second kettle body 121 and a second kettle cover 122 which are detachably connected. It should be noted that, the detachable connection in this embodiment may be a detachable connection that is conventionally used in the market, so long as a closed environment can be formed in the pressure-bearing kettle body 11 and the lining kettle body 12, which will not be described in detail herein.

The intermittent supercritical water oxidation reactor can reduce the constraint of the treated object on the shape and size, and is more suitable for treating urban solid wastes with complex structures and various types. Unlike continuous structure, batch reactors have frequent opening of the kettle for filling and taking of materials. However, in the traditional intermittent reactor structure, the kettle cover is not only connected and sealed with the kettle body, but also is connected with an external pipeline in order to facilitate design, and the connection of a plurality of positions reduces the opening speed of the kettle cover, so that the utilization rate of equipment is directly limited.

In order to avoid the influence of active engagement parts between the first kettle body 111 and the first kettle cover 112 and between the second kettle body 121 and the second kettle cover 122 as much as possible, the embodiment adopts a thimble type interface design and divides the conduit 15 into three-stage structures.

Specifically, the flow guiding tube 15 includes a first flow guiding tube 151, a second flow guiding tube 152 and a third flow guiding tube 153, which are sequentially communicated from end to end, the first flow guiding tube 151 is disposed on the first kettle body 111, the second flow guiding tube 152 is disposed on the first kettle cover 112, the third flow guiding tube 153 is disposed on the second kettle cover 122, one end of the first flow guiding tube 151 far away from the second flow guiding tube 152 is connected with the water-oxygen mixed fluid inlet 161, and one end of the third flow guiding tube 153 far away from the second flow guiding tube 152 is disposed in the reaction cavity 14.

Further, the first flow guiding tube 151 is an L-shaped tube, the second flow guiding tube 152 is a U-shaped tube, the third flow guiding tube 153 is a straight tube, the first kettle cover 112 is provided with a first through hole 113 and a second through hole 114 for the two ends of the second flow guiding tube 152 to pass through, the second kettle cover 122 is provided with a third through hole 123 for the third flow guiding tube 153 to pass through, and the axis of the first through hole 113 is parallel to the axis of the second through hole 114. When the first kettle body 111, the first kettle cover 112, the second kettle body 121 and the second kettle cover 122 are both closed, the axis of the second through hole 114 and the axis of the third through hole 123 are coincident, one end of the second flow guiding pipe 152 is penetrated in the first through hole 113 and is communicated with the first flow guiding pipe 151, the other end of the second flow guiding pipe 152 is penetrated in the second through hole 114 and is communicated with the third flow guiding pipe 153, the third flow guiding pipe 153 is penetrated on the third through hole 123, and one end far away from the second flow guiding pipe 152 extends to the bottom of the reaction cavity 14. The third flow guide pipe 153 is placed on the second kettle cover 122 and extends into the reaction cavity 14, and the pressure in the tank is balanced by means of the pressure in the reaction cavity 14, so that the sealing requirement on the joint is greatly weakened. Meanwhile, the first flow guide pipe 151 is fixedly arranged on the first kettle body 111, and the second flow guide pipe 152 is fixedly arranged on the first kettle cover 112, so that the first kettle cover 112 can be opened and closed better, and the second kettle cover 122 can be opened and closed better. Under the condition that the reasonable distribution of the guide pipes 15 can be ensured, the size of the whole pressure-bearing kettle body 11 is reduced, the sealing requirement on the joint is weakened, the opening rate of the kettle cover is improved, and the manufacturing cost of equipment is reduced. It should be noted that, the third flow guide tube 153 introduces supercritical water and oxygen into the bottom of the reaction cavity 14, the oxygen oxidizes the solid waste at the bottom, the oxidation rate and the decomposition amount of the solid waste are controlled by the oxygen concentration, and along with the oxidation of the bottom reactant, the oxygen is gradually transferred upwards to form a self-propagating reaction of a candle pile type from bottom to top, so that the raw materials with high solid content can be treated, and the controllability of the reaction rate and the decomposition rate is improved. In the reaction process, inorganic salt is automatically deposited at the bottom of the lining kettle body 12, after the reaction is completed, the first kettle cover 112 and the second kettle cover 122 can be opened, the inorganic salt in the lining kettle body 12 is recycled, the inorganic salt is not required to be discharged in the reaction process, and the risk of inorganic salt deposition blockage is eliminated.

Further, when the reaction vessel 1 is plural, the plural reaction vessels 1 may share auxiliary units such as the oxygen supply unit 2, the non-corrosive gas supply unit 3, the cooling water supply unit 4, the heating unit 5, and the energy recovery unit 6 through the split piping. The non-corrosive gas supply unit 3 is connected with the non-corrosive gas inlet 162 of each reaction kettle 1 through a pipeline and is communicated with the high-pressure cavity 13, the heating unit 5 is connected with the water-oxygen mixed fluid inlet 161 of each reaction kettle 1 through a pipeline and the oxygen supply unit 2 after converging and is communicated with the reaction cavity 14, the cooling water supply unit 4 is connected with the temperature control water inlet 163 of each reaction kettle 1 through a pipeline and is communicated with the high-pressure cavity 13, and the energy recovery unit 6 is connected with the kettle body outlet 164 of each reaction kettle 1 through a pipeline. The reaction heat is taken away by supercritical water, and the rest part is taken away by cooling water of the cooling water supply unit 4, so that the effective operation of the lining kettle body 12 is ensured.

The oxygen supply unit 2 includes a liquid oxygen tank 21, a liquid oxygen pump 22 and an oxygen heat exchanger 23 connected to each other, the non-corrosive gas supply unit 3 includes a gas tank 31 and a compressor unit 32 connected to each other, the cooling water supply unit 4 includes a first high-pressure water pump 41 and a first heat exchanger 42 connected to each other, and the energy recovery unit 6 includes a gas-liquid separator 61 and an expansion unit 62 connected to each other. The reaction heat in the lining kettle body 12 is taken away by spraying the outer wall of the lining kettle body 12 or immersing the cooling water, excessive temperature disturbance cannot be caused to the inside of the lining kettle body 12, the reaction rate of raw materials is guaranteed, water vapor and reaction gas products are discharged out of the reaction kettle 1 together, the expansion unit 62 is subjected to work recovery energy, the saved exhaust steam can continuously recover waste heat, and useful gases (hydrogen, methane and the like) in the waste heat are recovered and utilized.

The invention further provides a cross-critical zone heating unit 5, which specifically comprises a second high-pressure water pump 51, a second heat exchanger 52, a fourth flow guide pipe 53 and a heating kettle 54, wherein the heating kettle 54 is a heating kettle 54 with a cavity inside, a water inlet 541 and a water outlet 542 are arranged on the heating kettle 54, and the fourth flow guide pipe 53 is connected with the water inlet 541 and extends into the middle of the inner cavity of the heating kettle 54. Preferably, the outer side wall of the heating kettle 54 is provided with a heating jacket (not shown) for heating the heating kettle 54 and sleeved on the outer side wall of the heating kettle 54.

Further, at least one first-stage baffle plate 55 is arranged in the heating kettle 54, one end of the first-stage baffle plate 55 is connected with one side of the heating kettle 54, which is provided with a water inlet 541, a first-stage mixing cavity 551 is formed between the inner wall of the first-stage baffle plate 55 and the bottom of the heating kettle 54, one end of the fourth flow guide pipe 53 extends into the water inlet 541 and is arranged in the first-stage mixing cavity 551, a plurality of first flow guide holes 552 are formed at one end of the first-stage baffle plate 55, which is connected with the heating kettle 54, and the first-stage mixing cavity 551 is communicated with the inner cavity of the heating kettle 54 through the first flow guide holes 552.

Further, at least one secondary baffle plate 56 is further arranged in the heating kettle 54, the secondary baffle plate 56 is arranged on the periphery of the primary baffle plate 55, one end of the secondary baffle plate 56 is connected with the bottom of the heating kettle 54, a secondary mixing cavity 561 is formed among the inner wall of the secondary baffle plate 56, the outer wall of the primary baffle plate 55 and the bottom of the heating kettle 54, a tertiary mixing cavity 543 is formed between the inner wall of the heating kettle 54 and the outer wall of the secondary baffle plate 56, the primary mixing cavity 551 is communicated with the secondary mixing cavity 561 through a first diversion hole 552, a second diversion hole 562 is arranged at one end of the secondary baffle plate 56 far away from the bottom of the heating kettle 54, and the secondary mixing cavity 561 is communicated with the tertiary mixing cavity 543 through the second diversion hole 562. It should be noted that, when there are a plurality of primary baffles 55 and secondary baffles 56, the primary baffles 55 and the secondary baffles 56 are disposed in a crossing manner, and the secondary baffles 56 are disposed at the periphery of the adjacent primary baffles 55 all the time.

Preferably, the primary baffle 55 and the secondary baffle 56 are both corrosion resistant baffles, and the heating kettle 54 is a metal heating kettle 54. Separating the cooling water flowing out of the fourth draft tube 53 from the heating kettle 54 by the primary baffle 55 and the secondary baffle 56 effectively overcomes the problem of corrosion of the heating kettle 54, i.e., the heating kettle 54 suffering from corrosion is not subjected to pressure.

Further, a plurality of third diversion holes 531 are arranged at one end of the fourth diversion pipe 53 arranged in the first-stage mixing cavity 551, and the fourth diversion pipe 53 is communicated with the first-stage mixing cavity 551 through the third diversion holes 531. The stroke of working medium in the heating kettle 54 with limited volume can be increased by adjusting the length of the fourth flow guide pipe 53, the flow distribution structure of the third flow guide hole 531 and the like, so that the uniformity of flow distribution and heating is improved, and the large-temperature area crossing of supercritical fluid in a limited space is ensured.

Further, a plurality of temperature measuring points (not shown in the figure) are arranged on the water outlet 542 and the side wall of the heating kettle 54. The temperature measurement point of the water outlet 542 is to ensure that the temperature of the water outlet 542 is higher than the quasi-critical temperature, and the temperature measurement point of the side wall is to ensure that the near-wall fluid is also higher than the quasi-critical temperature.

The fourth flow guide pipe 53 is connected with the second heat exchanger 52, the second heat exchanger 52 heats the normal temperature medium to a preset temperature, and flows into the primary mixing cavity 551, the heating unit heats the heating kettle 54 for the second time and exchanges heat with the medium, and the preset temperature is higher than the supercritical temperature of the reaction liquid in the heating kettle 54.

The working procedure of the heating unit 5 of the present invention is: the normal temperature water is heated to a working condition lower than a critical area through a conventional second heat exchanger 52, the corrosiveness of the water in the temperature area is small, the water in the supercritical high-low temperature mixed heating kettle 54 is heated again, the temperature of the water in the kettle is controlled by a temperature controller all the time after the water in the kettle passes through the critical area only when being heated for the first time and is maintained in an area higher than the target temperature by 20-50 ℃, the preheated water is sent into the middle part of the high-pressure kettle through a fourth guide pipe 53, the water with the lower temperature is surrounded by the high temperature water and is diffused after being fused rapidly, and an inclined temperature layer is formed in the supercritical high-low temperature mixed heating kettle 54. Before the injected cold water reaches the heating kettle 54, the temperature of the mixed cold and hot fluid is higher than the temperature of the quasi-critical zone, so that the quasi-critical temperature zone is crossed.

The cross-critical zone heating unit 5 provided by the patent is not only limited to supercritical water cross-critical zone heating, but also can be used for heating/cooling other working media in a cross-temperature zone, and an inclined temperature layer is formed by mixing cold and hot fluid, so that the contact of an external wall surface and an undesirable working medium in a temperature zone is avoided. The heating kettle 54 can also serve as a buffer tank, and when parameters such as the flow rate, the pressure and the like of the working medium fluctuate, the influence of fluctuation of the operating parameters on the outlet temperature is counteracted by depending on the heat capacity of the working medium.

Further, control valves 7 are arranged at the water-oxygen mixed fluid inlet 161, the non-corrosive gas inlet 162, the temperature control water inlet 163 and the kettle outlet 164. Through detection and feedback of the internal pressure, a strong and robust valve 7 control strategy is developed to control the internal pressure of the reaction kettle 1 and discharge the product. From the safety point of view, the three-dimensional combination of valve 7 control, temperature control and oxygen concentration control is considered, so that the problem of pressure surge caused by fluctuation of the organic matter content of the raw materials due to the complexity of urban solid waste is effectively solved.

By adopting the design scheme, the invention has the beneficial effects that:

1. The intermittent reaction flow reconstruction is adopted, and the raw materials are directly filled into the lining kettle body 12 before the reaction starts, so that the treatment of the raw materials with high solid content can be realized;

2. introducing supercritical water and oxygen into the reaction cavity 14 of the lining kettle body 12 through the flow guide pipe 15, firstly oxidizing the bottom raw material to gradually form a self-propagating reaction of a candle pile from bottom to top, and controlling the reaction rate and the decomposition rate by controlling the injection rate of the supercritical water and the oxygen;

3. the high-pressure environment formed by non-corrosive gas is adopted to replace the water environment in the traditional supercritical water system, and the lining kettle body 12 is combined to perform double isolation on corrosive medium, so that the corrosion of the corrosive medium received by the surface of the external metal pressure-bearing kettle body 11 is prevented to the greatest extent, the service life of equipment is prolonged, and the operation safety of the equipment is ensured;

4. The intermittent supercritical water oxidation reactor can reduce the constraint of the treated object on the shape and size, and is more suitable for treating urban solid wastes with complex structures and various types.

5. The high-low temperature fluid mixing heating kettle 54 is designed, a stable inclined temperature layer is formed inside, the crossing of a working medium to a temperature zone is realized, and the inner wall of an external kettle body is prevented from being contacted with the working medium in a critical zone;

6. Optimizing the inclined temperature layer by means of the length of the fourth guide pipe 53, the flow distribution structures of the first guide holes and the third guide holes, the primary baffle plate, the secondary baffle plate and the like, so that the large temperature area crossing of the supercritical fluid is realized in a limited space;

7. the temperature of the outlet can be regulated by measuring the temperature of the inner wall surface of the heating kettle 54 and the temperature of the outlet of the heating kettle 54 and controlling the heating power of the second heat exchanger 52, the heating power of the heating kettle 54 and the flow rate of the working medium, so that the working medium flowing out of the heating kettle 54 can be ensured to cross the critical area, the development condition of an inclined temperature layer can be controlled, and the metal wall surface is ensured not to be contacted with the working medium in the critical area;

8. The heating kettle 54 can also serve as a buffer tank, when parameters such as the flow rate and the pressure of the working medium fluctuate, the influence of the fluctuation of the operation parameters on the outlet temperature is counteracted by depending on the heat capacity of the working medium, so that the operation of the heating system is more stable.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides a stride and imitate critical district heating system, includes fourth honeycomb duct and heating cauldron, the heating cauldron is the heating cauldron of inside being the cavity, be provided with water inlet and delivery port on the heating cauldron, fourth honeycomb duct with the water inlet is connected and stretches into the inner chamber middle part of heating cauldron, its characterized in that: the heating kettle comprises a water inlet, a heating kettle, a first-stage baffle plate, a second-stage baffle plate, a first-stage mixing cavity, a water inlet and a water outlet, wherein the water inlet is formed in the bottom of the heating kettle, one end of the fourth flow guide pipe stretches into the water inlet and is arranged in the first-stage mixing cavity, a plurality of first flow guide holes are formed in the first-stage baffle plate and the position of one end of the first-stage baffle plate, which is connected with the heating kettle, the first-stage mixing cavity is communicated with the inner cavity of the heating kettle through the first flow guide holes, and a heater for heating the heating kettle is arranged on the outer side wall of the heating kettle.

2. The cross-critical zone heating system of claim 1, wherein: the heating kettle is characterized by further comprising a secondary baffle plate, wherein the secondary baffle plate is arranged on the periphery of the primary baffle plate, a secondary mixing cavity is formed by the inner wall of the secondary baffle plate, the outer wall of the primary baffle plate and the bottom of the heating kettle, a tertiary mixing cavity is formed between the inner wall of the heating kettle and the outer wall of the secondary baffle plate, the primary mixing cavity is communicated with the secondary mixing cavity through the first diversion hole, a second diversion hole is formed in one end, far away from the bottom of the heating kettle, of the secondary baffle plate, and the secondary mixing cavity is communicated with the tertiary mixing cavity through the second diversion hole.

3. The cross-critical zone heating system of claim 2, wherein: at least one first-stage baffle plate, at least one second-stage baffle plate, a plurality of first-stage baffle plates and a plurality of second-stage baffle plates are arranged in a crossing way.

4. The cross-critical zone heating system of claim 1, wherein: one end of the fourth flow guide pipe, which is arranged in the primary mixing cavity, is provided with a plurality of third flow guide holes, and the fourth flow guide pipe is communicated with the primary mixing cavity through the third flow guide holes.

5. The cross-critical zone heating system of claim 2, wherein: the first-stage baffle plate and the second-stage baffle plate are corrosion-resistant baffle plates, and the heating kettle is a metal pressure-bearing heating kettle.

6. The cross-critical zone heating system of claim 1, wherein: the heater comprises a heating sleeve sleeved on the outer side wall of the heating kettle.

7. The cross-critical zone heating system of claim 1, wherein: and a plurality of temperature measuring points are arranged on the heating kettle.

8. The cross-critical zone heating system of claim 1, wherein: the high-pressure heating kettle is characterized by further comprising a high-pressure pump and a preheater, wherein the fourth flow guide pipe is connected with the preheater, the preheater heats normal-temperature medium to a preset temperature, the normal-temperature medium flows into the inner cavity of the heating kettle through the first-stage mixing cavity via the fourth flow guide pipe, the heater heats the heating kettle for the second time and exchanges heat with the medium, and the preset temperature is higher than the supercritical temperature of reaction liquid in the inner cavity of the heating kettle.

9. The cross-critical zone heating system of claim 1, wherein: still include reation kettle, reation kettle includes the pressure-bearing cauldron body and sets up the inside lining cauldron body of the pressure-bearing cauldron body, the pressure-bearing cauldron body with the lining cauldron body is the closed cauldron body, the inner wall of the pressure-bearing cauldron body with form the annular space between the outer wall of the lining cauldron body to constitute a confined high-pressure chamber, the inner chamber of the lining cauldron body forms a confined reaction chamber, be provided with water oxygen mixed fluid entry and intercommunication on the pressure-bearing cauldron body the high-pressure chamber is with the non-corrosive gas entry, the control by temperature change water entry of external and cauldron body export, the reaction chamber through a honeycomb duct with water oxygen mixed fluid entry is linked together.

10. The cross-critical section heating system of claim 9, wherein: the pressure-bearing kettle body comprises a first kettle body and a first kettle cover which are detachably connected, and the lining kettle body comprises a second kettle body and a second kettle cover which are detachably connected;