WO2007051411A1

WO2007051411A1 - Ammonia water absorption refrigerating device utilizing exhaust heat of tail gas

Info

Publication number: WO2007051411A1
Application number: PCT/CN2006/002926
Authority: WO
Inventors: Qidong Pang; Wenhui Zhang
Original assignee: Qidong Pang; Wenhui Zhang
Priority date: 2005-10-31
Filing date: 2006-10-31
Publication date: 2007-05-10
Also published as: CN1766462B; CN1766462A

Abstract

An ammonia water absorption refrigerating device utilizing exhaust heat of tail gas, comprises an ammonia water solution circulation loop and an ammonia circulation loop. In the cycle for ammonia water solution, before a cooled ammonia water strong solution from a solution pump (18) is heated by an exhaust heat generator (11), the strong sulution is preheated by a superheater (13), a rectifier (15), a generation-absorption heat exchanger (16) and a combination of a stripper (12) and the superheater (13). Cooling capacity of low temperature ammonia vapor from an evaporator (24) is withdrawn by liquid ammonia from a condenser (19) in a supercooler (20).

Description

Ammonia water absorption type refrigerating device using waste heat of exhaust gas

The present invention relates to an ammonia water absorption type refrigerating apparatus, and more particularly to an ammonia water absorption type refrigerating apparatus using waste heat of exhaust gas. Background technique

Ammonia absorption refrigeration is a thermal energy-based refrigeration method that has been widely used before vapor compression refrigeration. Ammonia absorption refrigeration is characterized by direct thermal energy, which requires only a small amount of auxiliary energy to achieve refrigeration. In addition, ammonia water absorption refrigeration has a large refrigeration temperature range, can be operated not only under air conditioning conditions, but also in various industrial refrigerations with a cooling temperature below zero Celsius. Therefore, under the condition of residual heat, most of the refrigeration requirements can be realized by the ammonia water absorption type refrigerating device, so that the waste heat can be reused, thereby achieving the purpose of energy saving.

However, due to the low refrigeration coefficient of ammonia water absorption refrigeration, the heat exchange equipment is bulky and has high investment cost, so it is greatly limited in use. For example, for transportation equipment such as automobiles and fishing boats, they all have the need for refrigeration. If they can use the waste heat of their engine exhaust to cool, it is an ideal choice for energy saving. However, for transportation equipment such as automobiles and fishing boats, since the structure is relatively compact and there is not much extra space, it is required to increase the refrigeration coefficient of the absorption refrigeration by installing the ammonia water absorption refrigeration equipment. In order to reduce the installation volume and weight, and to maximize the use of engine exhaust heat energy to achieve the highest cooling power.

The existing ammonia water absorption refrigeration device, as shown in FIG. 1, includes a generator 1, an absorber 2, a solution pump 3, a solution throttle valve 4, a regenerator 5, a fine concentrator 6, a condenser 7, and a throttling Valve 8, evaporator 9, etc. The high-temperature ammonia water dilute solution from the generator 1 enters the regenerator 5, passes through the heat exchange and cools, and then enters the absorber 2 through the solution throttle valve 4, and the dilute ammonia solution absorbs the ammonia gas in the absorber 2 and releases heat to absorb the ammonia gas. The concentrated aqueous ammonia solution enters the solution pump 3 from the bottom of the absorber 2, is then sent to the regenerator 5 by the solution pump 3, and is heated by the heat exchange to enter the generator 1 to be heated. This constitutes a circulation loop of the aqueous ammonia solution.

The ammonia-mixed steam from the generator 1 rises to the top rectifier 6, and the high-purity ammonia gas after the fractionation and rectification enters the condenser 7 to be condensed into liquid ammonia, and the liquid ammonia enters the evaporator 9 through the throttle valve 8. Evaporative cooling, the evaporated ammonia gas enters the absorber 2 and is absorbed into the concentrated ammonia aqueous solution by the dilute ammonia solution, and then enters the solution pump 3 from the bottom of the absorber 2, and is sent to the regenerator 5 by the solution pump 3, and after the heat is raised, the temperature is raised. The incoming generator 1 is heated. This constitutes a circulation loop of ammonia. The above-mentioned ammonia water absorption refrigeration device has a low refrigeration coefficient, and the refrigeration coefficient is in the range of 0.3 to 0.6 under different working conditions. The reason is: (1) The ammonia mixed steam is discharged when the rectifier 6 is fractionated. The heat is not used; (2) The heat released by the ammonia solution in the absorber 2 to absorb the ammonia gas is not utilized; (3) The cold amount of the low-temperature ammonia gas from the evaporator 9 is not recovered. Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide an ammonia water absorption type refrigerating apparatus which can directly utilize heating of engine exhaust gas and which has a high refrigeration coefficient and can fully utilize waste heat of exhaust gas, in order to overcome the deficiencies of the prior art.

In order to achieve the above problems, the present invention provides an ammonia water absorption type refrigerating apparatus using waste heat of exhaust gas, including a waste heat generator 1 1 , a rectifier 15 , a regenerator 13 , a solution throttle valve 21 , a throttle valve , and an evaporator 24 . a solution pump 18, a condenser 19, and an absorber 17, wherein the circulation circuit of the aqueous ammonia solution is: the shell solution outlet of the waste heat generator 1 1 is connected to the input end of the regenerator 13, and the output of the regenerator 13 The end is connected to the input end of the solution throttle valve 21, the output end of the solution throttle valve 21 is connected to the tube-length input end of the occurrence-absorption heat exchanger 16, and the absorption-absorption heat exchanger 16 is provided at the bottom end of the tube end and the absorber. The input of the absorber 17 is connected, the output of the absorber 17 is connected to the input of the rectifier 15 via a solution pump 18, and the output of the rectifier 15 is connected to the shell input of the generating-absorption heat exchanger 16, which occurs - The shell-side output end of the absorption heat exchanger 16 is connected to the top of the combination of the stripper 12 and the regenerator 13, the bottom of the combination of the stripper 12, the regenerator 13 and the vapor-liquid of the residual heat generator 1 1 shell Import and export connection The circulation loop of ammonia is: the vapor-liquid inlet and outlet of the residual heat generator 1 1 shell is connected with the bottom of the combination of the stripper 12 and the regenerator 13 , and the top of the combination of the stripper 12 and the regenerator 13 is fine The input end of the ammonia vapor channel of the rectifier 15 is connected, the output end of the ammonia vapor channel of the rectifier 15 is connected to the input end of the condenser 19, and the output end of the condenser 19 is passed through the primary throttle valve 22 and the recirculator 20 liquid ammonia channel. The input end is connected, the output end of the liquid ammonia channel of the chiller 20 is connected to the input end of the evaporator 24 through the secondary throttle valve 23, and the output end of the evaporator 24 is connected to the input end of the ammonia vapor channel of the chiller 20 The output of the ammonia vapor channel of the regenerator 20 is connected to the bottom of the shell of the generating-absorption heat exchanger 16, and the output end of the generating-absorption heat exchanger 16 is connected to the input end of the absorber 17, and the output of the absorber 17 The solution pump 18 is connected to the input end of the rectifier 15 and the output of the rectifier 15 is connected to the shell-side input of the absorption-absorption heat exchange 3⁄4, and the shell-side output of the generating-absorption heat exchanger 16 is raised. Distillator 12 regenerator 13 The top connector assembly, stripping unit 12, vapor-liquid export assembly 13 of the bottom portion of the regenerator 11 and the heat generator is connected to the shell.

Preferably, the stripper 12 and the regenerator 13 are of an integrated structure.

Preferably, the stripper 12 is composed of a set of trays 14 and an outer cylindrical tank, the trays 14 being perpendicular to the axis of the outer cylindrical cans and being fixed along the axial direction of the outer cylindrical cans The spacing is parallel and staggered, and the outer edge of the tray 14 is in intimate contact with the inner wall of the outer cylindrical can.

Preferably, the regenerator Π is in the shape of a spiral coil, and coils a set of trays 14 arranged in layers. between.

Preferably, the shape of the tray 14 is rounded, and a groove matching the shape of the spiral coil of the regenerator 13 is provided on the tray 14.

Preferably, the residual heat generator 11 is a shell-and-tube structure, which is composed of a cylindrical tank body and a column tube, a tail pipe of the exhaust heat generator 1 1 , an ammonia solution leaving the shell side of the heat recovery generator 11 , the column tube Threaded grooves are provided on the inner and outer walls.

Preferably, the occurrence-absorption heat exchanger 16 is a shell-and-tube structure composed of a cylindrical tank body and a column tube, and the occurrence-absorption heat exchanger 16 is vertically placed, and a cloth is placed on the top of the column tube. a liquid, a dilute solution of ammonia water from the solution throttle valve 21, flowing from the top of the column tube through the liquid dispenser to the inner wall of each of the tubes through the self-weight of the aqueous ammonia solution, and then From the bottom outlet of the generation-absorption heat exchanger (16) into the absorber 17, the solution from the rectifier 15 goes to the shell side of the generation-absorption heat exchanger (16), and enters and exits from the bottom. Stripper 12.

Preferably, the evaporator 24 is composed of a tube bundle and a casing, the tube bundle is composed of a pair of tubes closely adjacent to each other, and the refrigerant is taken away from the tube, and the refrigerant is taken away from the shell to bend the tube and the shell along the length direction. A certain shape, with grooves on the surface of the tube.

Preferably, the regenerator 20 is of a sleeve type structure in which three-dimensional fins are mounted on the heat exchange surface of the inner tube.

Compared with the prior art, the present invention has the following remarkable effects - as can be seen from the above technical solution, in the ammonia aqueous solution circulation loop, the cooled high-concentration ammonia aqueous solution from the solution pump 18 is sent back to the residual heat generator. 11 In the process of heating, in addition to the use of the heat of the regenerator 13, there are three places where the heat is effectively utilized:

(1) When entering the coiler of the rectifier 15 , heat is released when the water vapor is condensed by the splitting, and the heat is taken away by the aqueous ammonia solution in the coil;

(2) When entering the shell side of the occurrence-absorption heat exchanger 16, heat is generated when the ammonia solution of the tube process absorbs ammonia gas, and this heat is carried away by the ammonia aqueous solution of the shell side;

(3) The ammonia aqueous solution absorbs the heat of the high-temperature ammonia-mixed steam from the residual heat generator 1 when entering the inner chamber of the corrugator 12 and the regenerator 13 .

In summary, since the low-temperature ammonia aqueous solution fully utilizes the available heat in each step of the device in the process of being sent back to the residual heat generator 1 1 , the heat utilization efficiency of the entire device is greatly improved, and the efficiency is improved compared with the existing system. 50% - 100%.

Further, the low-temperature ammonia vapor from the evaporator 24 and the liquid ammonia from the condenser 19 are recovered in a cool amount in the regenerator 20. It is the effective use of these heat and cooling, so that the input heat load of the residual heat generator 11 is reduced under the unit cooling capacity, so the thermal coefficient of the device is effectively improved, and the energy saving effect is remarkable. The refrigeration coefficient of the device can reach 0.6-1.0 or more depending on the working conditions. The invention can be widely applied to the occasions where there is residual heat, such as exhaust gas discharged from an engine equipped with an automobile, a fishing boat, a generator, etc., and can also be applied to exhaust gas discharged from all combustion systems, and can also be applied to direct energy of non-remaining heat occasions. Heating form. DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention The principle. In the drawing:

1 is a schematic view showing the structure of a conventional ammonia water absorption type refrigerating apparatus.

2 is a schematic view showing the structure of an ammonia water absorption type refrigerating apparatus using waste heat of exhaust gas according to the present invention. The reference numerals are as follows:

Generator 1 absorber 2, solution pump 3

Solution throttle valve 4 regenerator 5 fear device 6

Condenser 7 throttle valve 8 evaporator 9

Waste heat generator 1 1 Lifter 12 Regenerator 13

Tray 14 Rectifier 15 Occupation-absorption heat exchanger 16 Absorber 17 Solution pump 18 Condenser 19

Regenerator .20 Solution Throttle 21 Primary Throttle 22 Secondary Throttle 23 Evaporator 24 Cylinder 25

Cooling terminal 26 Exhaust gas inlet 27 Exhaust gas outlet 28 Detailed description

Hereinafter, the ammonia water absorption type refrigerating apparatus using the waste heat of the exhaust gas of the present invention will be further explained in detail by way of a preferred embodiment.

2 is a schematic view showing the structure of an ammonia water absorption type refrigerating apparatus using waste heat of exhaust gas according to the present invention. As shown in Fig. 2, the present invention provides a utilization of an exhaust gas residual heat ammonia water absorption refrigeration device, and the working process is as follows:

The high-temperature ammonia water dilute solution from the waste heat generator 1 1 shell solution outlet enters the regenerator 13 and exchanges heat with the lower temperature ammonia water concentrated solution sent back to the waste heat generator 1 1 , and the temperature is lowered by the regenerator 13 After exiting, the solution throttle valve 21 enters the upper portion of the tube of the generation-absorption heat exchanger 16 to perform ammonia absorption and heat exchange, and then exits from the bottom of the tube of the generation-absorption heat exchanger 16 to enter the absorber 17 to further carry out ammonia. The absorption, while dissipating the heat generated by the absorption; the concentrated solution of ammonia water coming out of the absorber 17 enters the solution pump 18, and is sent by the solution pump 18 to the solution channel of the rectifier 15, where the ammonia water from the waste heat generator 11 is Mixing steam for heat exchange, During the rectification process, moisture is condensed and precipitated on the outer surface of the solution passage of the fine concentrator 15 and the heat is released, and the heat is transferred to the concentrated solution of ammonia in the spiral coil of the rectifier 15, and the concentrated solution of the ammonia after the absorption takes place again - Absorbing the shell side of the heat exchanger 16 to further absorb the heat released by the tube-forming dilute solution of the heat-generating heat exchanger 16 in the absorption of ammonia gas, and then entering the combination of the stripper 12 and the regenerator 13, and further The heat is absorbed and finally enters the residual heat generator 1 1 to complete the circulation of the aqueous ammonia solution.

The ammonia-mixed steam from the shell side of the waste heat generator 1 1 enters the combination of the stripper 12 and the regenerator 13 through the vapor-liquid inlet and outlet, and then enters the rectifier 15 to separate the water in the mixed steam, after the distillation The high-purity ammonia gas enters the condenser 19, and is condensed into liquid ammonia by heat dissipation. The liquid ammonia enters the liquid ammonia channel of the regenerator 20 through the primary throttle valve 22 for heat exchange, and then enters the evaporator through the secondary throttle valve 23. 24. The ammonia vapor from the evaporator 24 enters the ammonia vapor passage of the regenerator 20 for heat exchange, and then enters the bottom of the shell-side of the heat-generating heat exchanger 16 and the absorber 17 after being exchanged, and is absorbed by the aqueous ammonia solution. Here, the ammonia is taken into the above-mentioned ammonia aqueous solution circulation loop, and finally enters the residual heat generator 1 1, thereby completing the ammonia circulation.

The regenerator 20 can adopt a sleeve type structure, and three-dimensional fins are processed on the heat exchange surface of the inner tube, which further enhances the recycling of the cold amount. The low temperature ammonia vapor from the evaporator 24 exchanges heat with the liquid ammonia from the condenser 19 in the casing.

The regenerator 13 and the stripper 12 may be of an integrated structure. The stripper 12 may be composed of a ruthenium plate 14 and an outer cylindrical can. The tray 14 is perpendicular to the axis of the outer cylindrical can and is arranged in parallel at a certain interval in the axial direction. The edge of the tray 14 is The inner wall of the outer cylindrical can is in close contact. The regenerator 13 can be a spiral coil that is coiled between the layers of the tray 14. The shape of the trays 14 may be rounded, and the notches at the respective trays 14 constitute an ascending passage for the ammonia-mixed steam. The tray 14 is machined with a groove, and the position of the groove cooperates with the spiral coil (ie, the regenerator 13), which facilitates the flow of the solution on the tray 14 on the spiral coil, and the spiral The solution in the coil is subjected to heat exchange. The advantage of providing the regenerator 13 and the stripper 12 as an integrated structure is that the solution flowing back to the residual heat generator 1 1 is not only regenerated with the high temperature solution leaving the waste heat generator 1 1 but also with the residual heat. The high-temperature ammonia-water mixed steam of the device 1 1 is reheated, so that a better heat recovery effect can be achieved, which is advantageous for improving the thermal coefficient of the ammonia water absorption refrigeration device of the present invention.

The occurrence-absorption heat exchanger 16 may be a shell-and-tube structure composed of a casing and a set of tubes, and a liquid distributor is disposed at the top of the column, and the occurrence-absorption heat exchanger 16 is vertically placed from the solution. The ammonia solution of the throttle valve 21 is taken away from the tube at the top of the tube, and then flows through the inner wall of each tube uniformly by the self-weight of the liquid distributor, and then enters the absorber 17 from the bottom outlet. The solution from the fine concentrator 15 is taken to the stripper 12 from the bottom to the top. Since the tube's nitrogen solution absorbs ammonia, it generates heat, which is carried away by the shell-side ammonia solution. The column tube is machined with a thread groove on the inner and outer walls for enhancing heat exchange between the tube path solution and the shell side solution.

In order to cooperate with the utilization of waste heat of the exhaust gas, the heat generator 1 1 provided in the absorption refrigeration device of the present invention may be a relatively independent structure, and the generator 1 1 may be a shell and tube structure, and the cylindrical tank body and the Group management group to make. The tail gas is taken from the exhaust gas inlet 27 and discharged from the exhaust gas outlet 28. Ammonia solution takes the shell side. The waste heat generator 1 1 is connected to the stripper 12 through a pipe, and the ammonia water mixed steam from the waste heat generator 1 1 and the ammonia aqueous solution flowing back to the waste heat generator 1 1 flow through the connecting pipe. Thread grooves are formed in the inner and outer walls of the tube in the residual heat generator 1 1 to facilitate heat exchange between the engine exhaust and the ammonia solution.

The evaporator 24 can be a shell-and-tube structure, and is composed of a bundle of tubes and a casing which are closely arranged by a plurality of tubes, wherein the refrigerant takes the tube and the coolant carries the shell. The tube and the outer casing are bent into a certain shape along the length direction so as to reasonably arrange the installation space. The brine is circulated between the evaporator 24 and the cooling terminal 26 under the driving of the brine pump 25. The surface of the tube may be grooved to facilitate heat exchange between the brine and the refrigerant.

Claims

Rights request

1. An ammonia water absorption refrigeration device using waste heat of exhaust gas, comprising a waste heat generator (11), a rectifier (15), a regenerator (13), a solution throttle valve (21), a throttle valve, and an evaporator (24), solution pump (18), condenser (19), absorber (17), where:

The circulation circuit of the ammonia aqueous solution is: the shell solution outlet of the residual heat generator (11) is connected to the input end of the regenerator (13), the output end of the regenerator (13) and the input end of the solution throttle valve (21) Connected, the output of the solution throttle (21) is connected to the tube input of the generating-absorption heat exchanger (16), the tube-side bottom of the generating-absorption heat exchanger (16) is connected to the absorber (17) The input is connected, the output of the absorber (17) is connected to the input of the rectifier (15) via a solution pump (18), the output of the rectifier (15) and the generating-absorption heat exchanger (16) The shell side input is connected, the shell side output of the generating-absorption heat exchanger (16) is connected to the top of the combiner (12), the regenerator (13) assembly, the stripper (12), back The bottom of the assembly (13) is connected to the vapor-liquid inlet and outlet of the shell of the waste heat generator (11);

The circulation loop of ammonia is: waste heat generator (11) The vapor-liquid inlet and outlet of the shell side is connected with the bottom of the stack of the extractor (12) and the regenerator (13), the stripper (12) and the regenerator ( 13) The top of the assembly is connected to the input of the ammonia vapor channel of the rectifier (15), and the output of the ammonia vapor channel of the finer (15) is connected to the input of the condenser (19), condenser (19) The output of the liquid ammonia channel of the chiller (20) is connected to the output of the liquid ammonia channel of the chiller (20) through a secondary throttle valve (22), and the output of the liquid ammonia channel of the chiller (20) is passed through the secondary throttle valve (23). The input end of the evaporator (24) is connected, and the output of the evaporator (24) is connected to the input end of the ammonia vapor passage of the regenerator (20), and the output of the ammonia vapor passage of the regenerator (20) occurs - The bottom of the absorption heat exchanger (16) is connected to the bottom of the shell, the bottom end of the tube of the absorption-absorption heat exchanger (16) is connected to the input of the absorber (17), and the output of the absorber (17) is passed through the solution pump. (18) connected to the input of the rectifier (15), the output of the rectifier (15) occurs - the shell side input of the absorption heat exchanger (16) is connected, the shell side output of the generating-absorption heat exchanger (16) is connected to the top of the combination of the stripper (12) regenerator (13), stripping The bottom of the assembly of the regenerator (12) and the regenerator (13) is connected to the vapor-liquid inlet and outlet of the shell of the waste heat generator (11).

The ammonia water absorption refrigerating apparatus according to claim 1, characterized in that the stripper (12) and the regenerator (13) are of an integrated structure.

The ammonia water absorption type refrigerating apparatus according to claim 1 or 2, wherein: said stripper

(12) consisting of a set of trays (14) and outer cylindrical cans, the trays (14) being perpendicular to the axis of the outer cylindrical cans and parallel along the axial direction of the outer cylindrical cans And staggered, the outer edge of the tray (14) is in intimate contact with the inner wall of the outer cylindrical can.

The ammonia water absorption type refrigerating apparatus according to claim 1 or 2, wherein: said regenerator

(13) is a spiral coil shape and is coiled between a set of trays (14) arranged in layers. The nitrogen water absorption refrigerating apparatus according to claim 3, wherein the tray (14) has a round shape and is provided with a regenerator (13) on the tray (14). The spiral coil shape matches the groove.

6. The ammonia water absorption type refrigerating apparatus according to claim 1, wherein: said waste heat generator (11) is a shell-and-tube type structure, and is composed of a cylindrical tank body and a column tube, said exhaust gas being said The tube of the waste heat generator (11), the aqueous ammonia solution is taken away from the shell side of the waste heat generator (11), and the inner and outer walls of the tube are provided with screw grooves.

7. The ammonia water absorption type refrigerating apparatus according to claim 1, wherein: said generating-absorption heat exchanger (16) is a shell-and-tube type structure, and is composed of a cylindrical tank body and a column tube, and occurs - The absorption heat exchanger (16) is placed vertically, a liquid dispenser is arranged at the top of the column tube, and a dilute aqueous solution of the ammonia solution from the solution throttle valve (21) is passed through the tube of the generation-absorption heat exchanger (16). Passing through the liquid dispenser from the top of the tube and flowing evenly along the inner wall of each of the tubes by the self-weight of the diluted ammonia solution, and then entering through the bottom outlet of the generating-absorption heat exchanger (16) The absorber (17), the concentrated solution of ammonia water from the rectifier (15) goes to the shell side of the fine separator (15), and enters the stripper (12) and the regenerator (13) assembly from the bottom to the top. .

The ammonia water absorption type refrigerating apparatus according to claim 1, wherein: the evaporator (24) is a shell-and-tube structure, and is composed of a tube bundle and an outer casing, and the tube bundle is composed of a group of tubes closely adjacent to each other. And the refrigerant is taken away from the tube, and the refrigerant is taken away from the shell, the tube and the shell are bent into a certain shape along the length direction, and a groove is formed on the surface of the tube.

9. The ammonia water absorption refrigerating apparatus according to claim 1, wherein: said regenerator (20) is a sleeve type structure, said sleeve type structure including an inner tube, and heat exchange in said inner tube Three-dimensional ribs are mounted on the surface.