CN105526812B - A kind of catalysis oxidation heat exchanger and its method of work - Google Patents

Abstract

The invention discloses a catalytic oxidation heat exchanger and its working method, which comprises a shell, and the two ends of the shell are provided with a head I and a head II, and a heat exchange chamber is formed inside; the inside of the shell is connected with the head I and the head II The radial tube sheets are sealed between them, and there are tube holes for the heat exchange channel to pass through on the radial tube plate. The heat exchange channel connects the head I and the head II, and the heat exchange channel and the head form a fluid channel in the tube. ; The housing is also provided with a plurality of baffles parallel to the radial tube sheet to separate the heat exchange cavity to form an outer fluid channel, one end of the outer fluid channel communicates with the outer fluid inlet on the top of the shell, and the tube The other end of the outer fluid passage is connected with the outlet of the outer fluid at the bottom of the casing; the heat exchange passage includes a heat exchange tube, and the outside of the heat exchange tube is wrapped with foam metal, and the foam metal is built with catalytically active particles. The use of low-temperature catalytic oxidation technology solves the problem of difficult utilization of low-grade gas, which has dual meanings of energy saving and environmental protection.

Description

A catalytic oxidation heat exchanger and its working method

technical field

The invention relates to a catalytic oxidation heat exchanger and its working method for realizing low-grade gas heat recovery and low energy consumption treatment.

Background technique

Low-grade gas refers to the gas containing low-concentration combustible gas (CH4, CO, H2) that is difficult to use in industrial production. For example, ultra-low concentration coalbed methane, low-quality fossil gas fuels such as mine ventilation, or other low-concentration fuel-type exhaust gases. Under normal conditions, this part of the gas cannot be ignited or sustain combustion.

At present, most of the low-grade combustible gases in the world are directly discharged to the atmosphere without recycling. The emission of such gases, on the one hand, has caused a serious waste of limited non-renewable resources, and on the other hand, has also aggravated environmental pollution and the greenhouse effect. Therefore, reasonable recovery and utilization of low-concentration coalbed methane has dual meanings of energy saving and environmental protection.

In my country and many countries in the world, the research on low-grade gas utilization technology mainly focuses on: low-grade gas power generation technology, low-grade gas compression technology, low-grade gas combustion technology, and low-grade gas utilization technology for mine exhaust air, but these technologies No major breakthrough has been made, and there are problems such as low power generation efficiency and potential safety hazards, and there are still great gaps in development and utilization.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, provide a catalytic oxidation heat exchanger and its working method, adopt the low-temperature catalytic oxidation technology, carry out simple modification to the ordinary heat exchanger, and solve the problem of difficult utilization of low-grade gas , has dual meanings of energy saving and environmental protection.

To achieve the above object, the present invention adopts the following technical solutions:

A catalytic oxidation heat exchanger,

Including the shell, the two ends of the shell are provided with a head I and a head II, and a heat exchange chamber is formed inside;

A radial tube plate is sealed between the shell and the head I and II, and there are tube holes on the radial tube plate for the passage of the heat exchange channel, and the heat exchange channel connects the head I and the head II. Connected, the head I is divided into two parts by a horizontal partition, the top of the head I has the fluid inlet in the tube, the bottom has the fluid outlet in the tube, the heat exchange channel forms the fluid channel in the tube with the head I and the head II; the shell There are also a plurality of baffles parallel to the radial tube sheet inside to separate the heat exchange cavity to form an outer tube fluid channel. One end of the outer tube fluid channel communicates with the outer tube fluid inlet on the top of the shell, and the outer tube fluid channel The other end communicates with the fluid outlet outside the tube at the bottom of the shell;

The heat exchange channel includes a heat exchange tube, and the outside of the heat exchange tube is wrapped with metal foam, and the metal foam is built with active particles with catalytic activity.

Preferably, the inlet of the fluid outside the tube is located at the top of the end of the shell provided with the head II; the outlet of the fluid outside the tube is located at the bottom of the end of the shell provided with the head I; to ensure sufficient heat absorption of the fluid outside the tube.

A catalytic oxidation heat exchanger,

Including the shell, the two ends of the shell have head I and head II, and a heat exchange chamber is formed inside;

A radial tube plate is sealed between the shell and the head I and II, and there are tube holes on the radial tube plate for the passage of the heat exchange channel, and the heat exchange channel connects the head I and the head II. The top of the head I has a fluid inlet in the tube, the bottom of the head II has a fluid outlet in the tube, and the heat exchange channel forms a fluid channel in the tube with the head I and the head II; A plurality of baffles are used to separate the heat exchange chamber to form a fluid channel outside the tube. One end of the fluid channel outside the tube communicates with the fluid inlet outside the tube at the top of the shell, and the other end of the fluid channel outside the tube communicates with the fluid outlet outside the tube at the bottom of the shell. connected;

The heat exchange channel includes a heat exchange tube, and the outside of the heat exchange tube is wrapped with metal foam, and the metal foam is built with active particles with catalytic activity.

The metal foam is made of metal with high thermal conductivity, and the metal substance of the metal foam can be metal with high thermal conductivity such as nickel, copper, iron, aluminum, etc., preferably copper.

The pore size range of the metal foam is 0.1-2mm, preferably 0.5mm.

Preferably, the inlet of the fluid outside the tube is located at the top of the end of the shell provided with the head I; the outlet of the fluid outside the tube is located at the bottom of the end of the shell provided with the head II; to ensure sufficient heat absorption of the fluid outside the tube.

A temperature measuring element is provided at the inlet of the fluid in the tube, and the temperature measuring element communicates with the controller; the temperature of the fluid in the tube can be controlled by the controller by measuring the temperature at the inlet of the fluid in the tube.

A plurality of pores are arranged in the metal foam, and active particles are attached to the pores.

The active particle is a low-temperature oxidation catalyst, which is used to catalyze the oxidation of low-grade gas at low temperature (100-500°C). The low-temperature oxidation catalyst includes a carrier and an active metal, and the active metal is loaded on the carrier; the carrier is a molecular sieve The material is titanium dioxide or activated alumina, and the active metal is composed of one or more of iron, copper, nickel, cobalt, chromium, vanadium, manganese, barium, magnesium, calcium, and silver metals. The method of loading the active metal on the carrier can adopt catalyst preparation methods such as impregnation method and hydrothermal method.

The method of attaching the active particles to the metal foam can be spraying, that is, the mixed liquid of the catalyst is made into a uniform solution, and the solution is sprayed on the surface of the metal foam with a high-pressure spray gun; , spray the catalyst particles on the surface of the metal foam and form a stable bond; or use the impregnation method, that is, the catalyst particles are made into an emulsion solution, and the metal foam is immersed in it to make the catalyst particles form a stable attachment on the surface of the metal foam. Other methods of forming a stable attachment of the catalyst particles to the metal foam surface can also be used.

The pores are evenly distributed in the metal foam; the heat of the fluid outside the tube is evenly absorbed, and the catalytic oxidation rate of the active particles to the fluid outside the tube is improved.

The porosity of the metal foam is greater than 90%, and the contact area between the inner filling catalyst and the gas is greatly increased.

The flow area of the fluid channel outside the tube is 4 to 9 times that of the fluid channel inside the tube; the foam metal expansion is prevented from blocking the fluid flow outside the tube.

A sealing element is provided between the shell and the heads I and II, and a sealing element is arranged between the heat exchange channel and the radial tube sheet to ensure the sealing of the heat exchange cavity and improve the heat exchange efficiency.

A working method of a catalytic oxidation heat exchanger, comprising the following steps:

Step 1: The heat-absorbing fluid enters from the fluid inlet in the pipe, and the heat-absorbing fluid circulates in the fluid passage in the pipe; the low-grade combustible gas enters from the fluid inlet outside the pipe, and the low-grade combustible gas circulates in the fluid passage outside the pipe;

Step 2: The low-grade combustible gas is catalyzed and oxidized by the active particles in the metal foam of the heat exchange channel, and the released heat is absorbed by the heat-absorbing fluid in the heat exchange channel;

Step 3: The treated low-grade combustible gas flows out from the fluid outlet outside the pipe, and the heat-absorbing fluid flows out from the fluid outlet inside the pipe to realize heat recovery and pollution-free discharge of low-grade gas.

Working principle of the present invention is:

Using the catalytic oxidation heat exchanger of the present invention, when the high-temperature and low-grade gas circulates, it is catalyzed and oxidized under the action of the catalyst, and the heat released is transferred to the heat exchange tube in time through the foam metal, taken away by the fluid in the heat exchange tube and used in time to realize Heat recovery of low-grade gas; the temperature of the catalyst filled in metal foam can also be controlled by controlling the flow and temperature of the fluid in the heat exchange tube, so as to catalyze the oxidation of low-grade gas to achieve low energy consumption.

The beneficial effects of the present invention are:

The catalytic oxidation heat exchanger of the present invention catalyzes and oxidizes the low-grade combustible gas through the active particles of the heat-exchange tube, and the heat of the low-grade combustible gas is recycled by the heat-exchanging tube to realize low-energy treatment and heat recovery and utilization of the low-grade combustible gas .

The catalytic oxidation reaction only occurs on the surface of the heat exchange tube, and the heat release process is limited to the surface of the heat exchange tube. The heat can be taken away and utilized in a timely and effective manner, instead of being used to heat other gases in a large area. The heat utilization High rate.

The catalytic oxidation heat exchanger of the present invention effectively solves the problem of difficult utilization of low-grade gas, and has dual meanings of energy saving and environmental protection; at the same time, the fluid in the heat exchange tube can be recycled to save resources.

The catalytic oxidation heat exchanger of the invention can be realized by simply modifying the conventional heat exchanger, and the cost is low.

Description of drawings

Fig. 1 is the structural representation of catalytic oxidation heat exchanger of the present invention;

Fig. 2 is the structural representation of metal tube in Fig. 1;

In the figure, 1 is the fluid inlet in the tube; 2 is the thermocouple; 3 is the partition; 4 is the fluid outlet in the tube; 5 is the fluid outlet outside the tube; 6 is the shell; 7 is the metal tube; Baffle; 10 is the tube sheet; 11 is the control system; 12 is the foam metal; 13 is the hole; 14 is the active particle; 15 is the head.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example 1:

As shown in Figure 1, the catalytic oxidation heat exchanger is used to realize low-grade gas heat recovery and low energy consumption treatment. The heat exchanger can be realized by simple modification of the conventional heat exchanger, and the cost is low. Tube plate, spiral plate and other types.

The catalytic oxidation heat exchanger includes a shell 6, the two ends of the shell 6 have heads 15, and a heat exchange chamber is formed inside; the two ends of the shell 6 are provided with radial tube sheets 10, which are sealed; The heat channel passes through the tube hole, and the heat exchange channel connects the two heads 15. The top of the head 15 at one end has the fluid inlet 1 in the pipe, and the fluid outlet 4 in the pipe at the bottom. The head 15 is divided into two by the horizontal partition 3. part, the heat exchange channel and the head 15 form a fluid channel in the tube; a plurality of baffles (ie, baffles 9) parallel to the radial tube sheet 10 are also arranged in the shell 6 to separate the heat exchange cavity to form the fluid outside the tube Channel, one end of the fluid channel outside the tube communicates with the fluid inlet 8 outside the tube at the top of the housing 6 , and the other end of the fluid channel outside the tube communicates with the fluid outlet 5 outside the tube at the bottom of the housing 6 .

Low-grade gas is mainly low-quality fossil gas fuels such as ultra-low concentration coalbed methane, mine ventilation, or other low-concentration fuel-type waste gases.

There is a thermocouple 2 at the inlet 1 of the fluid in the tube, and the thermocouple 2 communicates with the control system 11; the control system 11 can control the temperature of the active particles 14 in the foam metal 12 of the heat exchange channel, and can also control the metal tube 7 of the heat exchange channel fluid flow within. Among them, the temperature control can be realized by adjusting the flow rate, reducing the flow rate of the fluid in the tube can increase the temperature of the fluid in the tube and the tube wall, and then control the overall temperature of the heat exchanger; the flow control can be realized by adjusting the inlet valve.

A sealing ring is provided between the shell 6 and the head 15 for sealing, and a sealing ring is provided between the heat exchange channel and the radial tube sheet 10 for sealing.

The fluid flow area of the fluid channel outside the tube is 4 to 9 times the fluid flow area of the fluid channel inside the tube, preventing the expansion of the foam metal from blocking the fluid flow outside the tube.

As shown in Figure 2, the structure of the heat exchange channel is a heat exchange tube (i.e. metal tube 7) welded with porous metal foam 12, and the pores 13 of the metal foam can be filled with catalytically active active particles 14 to realize the catalysis of specific gases. oxidation. The fluid in the metal pipe 7 can be recycled to save resources.

The metal foam 13 has a porosity of more than 90%, and the pore diameter can reach millimeter level, which greatly increases the contact area between the inner filling active particles 14 and the gas; it has good thermal conductivity and can transfer heat in a timely and effective manner. Aluminum foam and its alloys can be used, which is economical.

Most studies have shown that combustible gas can be oxidized to produce harmless gas under the action of a suitable catalyst at a temperature of 100°C to 500°C, so it can be treated by low-temperature catalytic oxidation technology.

Water or water vapor enters through the fluid inlet 1 in the tube, flows in the metal tube 7, and flows out through the fluid outlet 4 in the tube. The low-grade combustible gas flows into the heat exchanger from the fluid inlet 8 outside the pipe, and is catalyzed and oxidized under the action of a suitable catalyst 14 at a temperature of 100°C to 300°C, and the released heat is transferred to the metal pipe 7 in time through the foam metal 12, It is taken away by the fluid in the pipe and used in time, and the treated low-grade combustible gas flows out from the fluid outlet 5 outside the pipe to realize heat recovery and pollution-free discharge of the low-grade gas; it can also be controlled by the fluid flow and temperature control system 11 in the metal pipe. The temperature and flow rate of the fluid are to keep the active particles 14 filled in the metal foam to reach the reaction temperature, so as to catalyze the oxidation of low-grade gas and realize low-energy treatment.

The catalytic oxidation heat exchanger adopts low-temperature catalytic oxidation technology to realize low-grade gas heat recovery and low energy consumption treatment, which has dual meanings of energy saving and environmental protection.

The temperature of the catalytic oxidation reaction is 100°C to 500°C, and the reaction only occurs on the surface of the metal tube, so the heat release process is limited to the surface of the metal tube, and the heat can be taken away and utilized in a timely and effective manner instead of being used for Heating other gases in a large area with high heat utilization.

Example 2:

A sealing ring is provided between the shell 6 and the head 15 for sealing, and a sealing ring is provided between the heat exchange channel and the radial tube sheet 10 for sealing.

Example 3:

Sealing grooves are set on the shell 6 and the head 15, and O-rings are fixed in the sealing grooves for sealing; sealing grooves are set on the heat exchange channel and the radial tube sheet 10, and O-rings are fixed in the sealing grooves for sealing;

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (10)

1. A catalytic oxidation heat exchanger is characterized in that, Including the shell, the two ends of the shell are provided with a head I and a head II, and a heat exchange chamber is formed inside; A radial tube plate is sealed between the shell and the head I and II, and there are tube holes on the radial tube plate for the passage of the heat exchange channel, and the heat exchange channel connects the head I and the head II. Connected, the head I is divided into two parts by a horizontal partition, the top of the head I has the fluid inlet in the tube, the bottom has the fluid outlet in the tube, the heat exchange channel forms the fluid channel in the tube with the head I and the head II; the shell There are also a plurality of baffles parallel to the radial tube sheet inside to separate the heat exchange cavity to form an outer tube fluid channel. One end of the outer tube fluid channel communicates with the outer tube fluid inlet on the top of the shell, and the outer tube fluid channel The other end communicates with the fluid outlet outside the tube at the bottom of the shell; The heat exchange channel includes a heat exchange tube, the heat exchange tube is covered with metal foam, and the metal foam contains active particles with catalytic activity; the metal foam is provided with a plurality of pores, and the active particles are attached to the pores; The active particle is a low-temperature oxidation catalyst, and the low-temperature oxidation catalyst includes a carrier and an active metal, and the active metal is loaded on the carrier. 2. The catalytic oxidation heat exchanger according to claim 1, characterized in that, the inlet of the fluid outside the tube is located at the top of the end of the shell with the head II; the outlet of the fluid outside the tube is located at the end of the shell with the head I bottom of one end. 3. A catalytic oxidation heat exchanger, characterized in that, Including the shell, the two ends of the shell have head I and head II, and a heat exchange chamber is formed inside; A radial tube plate is sealed between the shell and the head I and II, and there are tube holes on the radial tube plate for the passage of the heat exchange channel, and the heat exchange channel connects the head I and the head II. The top of the head I has a fluid inlet in the tube, the bottom of the head II has a fluid outlet in the tube, and the heat exchange channel forms a fluid channel in the tube with the head I and the head II; A plurality of baffles are used to separate the heat exchange chamber to form a fluid channel outside the tube. One end of the fluid channel outside the tube communicates with the fluid inlet outside the tube at the top of the shell, and the other end of the fluid channel outside the tube communicates with the fluid outlet outside the tube at the bottom of the shell. connected; The heat exchange channel includes a heat exchange tube, the heat exchange tube is covered with metal foam, and the metal foam contains active particles with catalytic activity; the metal foam is provided with a plurality of pores, and the active particles are attached to the pores; The active particle is a low-temperature oxidation catalyst, and the low-temperature oxidation catalyst includes a carrier and an active metal, and the active metal is loaded on the carrier. 4. The catalytic oxidation heat exchanger according to claim 3, characterized in that, the inlet of the fluid outside the tube is located at the top of the end of the shell provided with the head I; the outlet of the fluid outside the tube is located at the end of the shell provided with the head II bottom of one end. 5. The catalytic oxidation heat exchanger according to claim 1 or 3, wherein a temperature measuring element is provided at the inlet of the fluid in the tube, and the temperature measuring element communicates with the controller. 6. The catalytic oxidation heat exchanger according to claim 1 or 3, characterized in that, the metal foam is made of metal with high thermal conductivity; the pore diameter of the metal foam is in the range of 0.1-2 mm. 7. The catalytic oxidation heat exchanger as claimed in claim 1 or 3, wherein the pores are evenly distributed in the metal foam; the porosity of the metal foam is greater than 90%; the carrier adopts molecular sieve material or titanium dioxide Or activated alumina, the active metal is composed of one or more of iron, copper, nickel, cobalt, chromium, vanadium, manganese, barium, magnesium, calcium, silver metal. 8. The catalytic oxidation heat exchanger according to claim 1 or 3, wherein the flow area of the fluid channel outside the tube is 4 to 9 times the flow area of the fluid channel inside the tube. 9. The catalytic oxidation heat exchanger according to claim 1 or 3, characterized in that, sealing elements are provided between the shell and the heads I and II, and the heat exchange channel and the radial tube sheet A sealing element is provided between them. 10. Utilize the working method of claim 1 or 3 described catalytic oxidation heat exchangers, it is characterized in that, comprise the following steps: Step 1: The heat-absorbing fluid enters from the fluid inlet in the pipe, and the heat-absorbing fluid circulates in the fluid passage in the pipe; the low-grade combustible gas enters from the fluid inlet outside the pipe, and the low-grade combustible gas circulates in the fluid passage outside the pipe; Step 2: The low-grade combustible gas is catalyzed and oxidized by the active particles in the metal foam of the heat exchange channel, and the released heat is absorbed by the heat-absorbing fluid in the heat exchange channel; Step 3: The treated low-grade combustible gas flows out from the fluid outlet outside the pipe, and the heat-absorbing fluid flows out from the fluid outlet inside the pipe to realize heat recovery and pollution-free discharge of low-grade gas.