CN205423171U - Oil-free screw air compressor heat recovery cascade utilization system - Google Patents

Abstract

The utility model discloses a there is not oily screw compressor heat recovery cascade utilization system, including air compressor machine cooling device, hot water cascade utilization device and demineralized water device, wherein, air compressor machine cooling device mainly includes two compression host and two guarantee heat exchangers and water pump, burns and is connected through the pipe network between hot water cascade utilization device and the air compressor machine cooling device, the demineralized water device passes through demineralized water inlet tube and water storage tank connection. Can not carry out waste heat recovery to there being oily screw compressor, obtained the hot water of needs, and carried out cascade utilization to hot water.

Description

Oil-free screw air compressor heat recovery cascade utilization system

technical field

The utility model belongs to the technical field of heat recovery of air compressors, and relates to a heat recovery cascade utilization system of an oil-free screw air compressor.

Background technique

With the increasing tension of energy, the issue of energy saving has become the focus of global attention. While actively developing new energy sources, more and more attention should be paid to recycling and utilizing waste heat resources. According to a statistics from the U.S. Department of Energy, among the electricity consumed by the compressor during operation, only 15% of the total electricity consumption is actually used to increase the potential energy of the air, while most of the rest (about 85%) of the electricity is converted into heat. The heat is generally discharged into the air through air cooling or water cooling, resulting in a great waste of energy.

One of the main directions of energy saving in the compressed air system is the waste heat recovery of the air compressor. Therefore, some methods and equipment are used to recycle the waste heat generated by the air compressor to obtain the required hot water at different temperatures, and the rational use of hot water at different temperatures can maximize energy recovery and reduce energy consumption. , save most of the cost for the enterprise, and reduce environmental waste heat pollution.

At present, there are some related researches on the waste heat recovery of air compressors, but there are relatively few studies on the heat recovery of oil-free screw air compressors. little.

Utility model content

The purpose of the utility model is to provide a heat recovery cascade utilization system for an oil-free screw air compressor, which can recover the waste heat of the oil-free screw air compressor, obtain the required hot water, and carry out cascade utilization of the hot water.

The technical scheme adopted by the utility model is an oil-free screw air compressor heat recovery cascade utilization system, including an air compressor cooling device, a hot water cascade utilization device and a softening water device; wherein, the air compressor cooling device mainly includes Two compressor hosts, two guarantee heat exchangers and water pumps, the hot water cascade utilization device and the air compressor cooling device are connected through a pipe network; the softened water device is connected to the water storage tank through a softened water inlet pipe.

The utility model is also characterized in that the structure of the air compressor cooling device includes a first compressor host and a second compressor host, the first compressor host is connected to the first guarantee heat exchanger through the first ventilation pipe, and the second compressor host is The second ventilation pipe is connected to the second guarantee heat exchanger, the first air compressor outlet pipe and the first air compressor water inlet pipe are respectively arranged on the first compressor main engine, and the second air compressor is respectively arranged on the second compressor main engine The water outlet pipe and the water inlet pipe of the second air compressor, the first guarantee heat exchanger is provided with the first guarantee heat exchanger outlet pipe and the first guarantee heat exchanger inlet pipe, and the second guarantee heat exchanger is provided with a second guarantee The outlet pipe of the heat exchanger and the inlet pipe of the second guarantee heat exchanger; the outlet pipe of the first guarantee heat exchanger and the outlet pipe of the second guarantee heat exchanger are connected to the outlet pipe of the heat exchanger. The water inlet pipe of the second air compressor, the water inlet pipe of the first guarantee heat exchanger and the water inlet pipe of the second guarantee heat exchanger are all connected to the main water inlet pipe; the water outlet pipe of the first air compressor and the water outlet pipe of the second air compressor are connected with the air compressor The main outlet pipe is connected; the heat exchanger outlet pipe is connected to the air compressor main outlet pipe, and a valve D is set at the connection.

The hot water cascade utilization device includes four plate heat exchangers, and the plate heat exchangers are connected to the cooling device of the air compressor and the high-temperature hot water end and the low-temperature hot water end through the pipe network. The four heat exchangers are the first plate heat exchanger, the second plate heat exchanger, the third plate heat exchanger, and the fourth plate heat exchanger, wherein the first plate heat exchanger and the second plate heat exchanger The hot spot of high-temperature hot water is connected through the pipe, the third plate heat exchanger and the fourth plate heat exchanger are connected with the hot spot of low-temperature hot water through the pipe; The second plate heat exchanger is connected to the main water outlet pipe of the air compressor through the fifth high temperature end water exchange pipe; the third plate heat exchanger is connected to the air compressor main water outlet pipe through the second low temperature end water exchange pipe The fourth plate heat exchanger is connected to the main water outlet pipe of the air compressor through the fifth low-temperature end heat exchange pipe.

The hot end of the first plate heat exchanger is provided with a first high temperature end heat exchange pipe; the second high temperature end heat exchange pipe communicates with the second plate heat exchanger and communicates with the first high temperature end heat exchange pipe; The water exchange pipe at the end is connected with the second plate heat exchanger, the sixth high temperature end water exchange pipe is also provided on the first plate heat exchanger, the fourth high temperature end water exchange pipe is connected with the sixth high temperature end water exchange pipe, for Water at a lower temperature is passed into the plate heat exchanger for heat exchange with the hot water sent from the main outlet pipe of the air compressor, thereby ensuring the water temperature at the high-temperature water end.

The water exchange pipe at the fifth high temperature end is connected to the water exchange pipe at the second high temperature end; a valve A is provided between the water exchange pipe at the second high temperature end and the water exchange pipe at the fifth high temperature end on the main water outlet pipe of the air compressor.

On the main water outlet pipe of the air compressor, there is a valve B connecting the water outlet pipe of the heat exchanger and the main water outlet pipe of the air compressor between the fifth high temperature end heat exchange water pipe and the second low temperature end water exchange water pipe; the third plate heat exchange The heat exchange pipe at the first low temperature end is provided on the heat exchanger, and the water exchange pipe at the fourth low temperature end is provided on the fourth plate heat exchanger. The water outlet point of the use end, the sixth low-temperature end heat exchange pipe and the fourth low-temperature end heat exchange pipe are connected, as the water inlet end of the low-temperature hot water use end, and the cold water at the low-temperature water end is delivered to the third plate heat exchanger and the fourth plate heat exchanger In the heater, the usable low-temperature hot water flows out from the first low-temperature end heat exchange pipe and the third low-temperature end heat exchange pipe for users to use after the heat exchange is completed.

The water exchange pipe at the second low temperature end and the water exchange pipe at the fifth low temperature end are also connected to each other, and are installed on the main water outlet pipe of the air compressor between the water exchange pipe at the fifth low temperature end and the water exchange pipe at the second low temperature end There is valve C.

The end of the main water outlet pipe of the air compressor leads into the shell-and-tube heat exchanger, and a valve E is installed at the position close to the shell-and-tube heat exchanger on the main water outlet pipe of the air compressor, and a return pipe is also arranged on the main water outlet pipe of the air compressor , one end of the return pipe is connected to the shell-and-tube heat exchanger, and the other end is located at the connection point of the fifth low-temperature end water exchange pipe and the main outlet pipe of the air compressor, and the connection point between the outlet pipe of the heat exchanger and the main outlet pipe of the air compressor position between.

The return pipe is connected to the water storage tank through the water inlet pipe of the water storage tank. The water storage tank is also connected to the main water inlet pipe. The water storage tank is connected to the softened water device through the softened water inlet pipe. The shell-and-tube heat exchanger is connected to the The cooling tower is connected, and a cooling tower water inlet pipe is also arranged between the cooling tower and the shell-and-tube heat exchanger, and a valve is arranged on the cooling tower water inlet pipe.

The beneficial effect of the utility model is that the oil-free screw air compressor is modified for heat recovery, and in the internal cooling system of the oil-free screw air compressor, the intercooler and the aftercooler are connected in parallel, so that the outlet temperature of the cooling water is higher , is easier to be recycled, saves energy, avoids waste of resources, and realizes efficient use of recovered heat, which improves the economic benefits of the enterprise.

Description of drawings

Fig. 1 is a structural schematic diagram of the heat recovery cascade utilization system of the oil-free screw air compressor of the present invention.

In the figure, 1. The first compressor host, 2. The second compressor host, 3. The first guarantee heat exchanger, 4. The second guarantee heat exchanger, 5. The first plate heat exchanger, 6. The second plate heat exchanger Heater, 7. Third plate heat exchanger, 8. Fourth plate heat exchanger, 9. Shell-and-tube heat exchanger, 10. Valve, 11. Cooling tower, 12. Softened water device, 13. Water storage tank , 14. Water pump, 15. Valve A, 16. Valve B, 17. Valve C, 18. Valve D, 19. Valve E, 20. Valve F, 1-1. The first air compressor outlet pipe, 1-2 .The water inlet pipe of the first air compressor, 1-3. The first air pipe, 2-1. The water outlet pipe of the second air compressor, 2-2. The water inlet pipe of the second air compressor, 2-3. The second air pipe , 3-1. Outlet pipe of the first guarantee heat exchanger, 3-2. Inlet pipe of the first guarantee heat exchanger, 4-1. Outlet pipe of the second guarantee heat exchanger, 4-2. Second guarantee heat exchanger Water inlet pipe, 21. Main water inlet pipe, 22. Air compressor main water outlet pipe, 23. Heat exchanger outlet pipe, 5-1. First high temperature end heat exchange pipe, 5-2 Second high temperature end heat exchange pipe, 5 -3. The water exchange pipe at the third high temperature end, 6-1. The water exchange pipe at the fourth high temperature end, 6-2. The water exchange pipe at the fifth high temperature end, 6-3. The heat exchange pipe at the sixth high temperature end, 7-1 .The first low temperature end heat exchange pipe, 7-2. The second low temperature end heat exchange pipe, 7-3. The third low temperature end heat exchange pipe, 8-1. The fourth low temperature end heat exchange pipe, 8-2. 5th low temperature end water exchange pipe, 8-3. sixth low temperature end water exchange pipe, 9-1. return pipe, 9-2. cooling tower water inlet pipe, 9-3. cooling tower water outlet pipe, 13-1. water storage Tank water inlet pipe, 13-2. softened water inlet pipe.

detailed description

The utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

An oil-free screw air compressor heat recovery cascade utilization system includes an air compressor cooling device, a hot water cascade utilization device, and a softened water device.

Among them, the air compressor cooling device mainly includes two compressor hosts, two guarantee heat exchangers and water pumps, which cool the air compressor unit and transfer energy under the action of the water circulation system. The heating water cascade utilization device and the air compressor cooling device are connected through a pipe network. Under the action of the water pump, the cooling water cools the two compressor hosts and the two guarantee heat exchangers, and transfers energy through the cooling water.

The softened water device is connected with the hot water cascade utilization device and the air compressor cooling device through pipelines.

At the same time, after the cooling water in the air compressor cooling device cools the air compressor unit, the hot water obtained is also the hot water source of the hot water cascade utilization device. The hot water enters the hot water cascade utilization device and transfers heat to the hot water end water system. In the hot water cascade utilization device, hot water enters different heat exchangers for heat exchange according to the temperature requirements of different supply hot spots to realize energy conversion.

Wherein, the structure of the air compressor cooling device, as shown in Figure 1, includes a first compressor host 1 and a second compressor host 2, and the first compressor host 1 connects with the first guarantee heat exchanger 3 through the first ventilation pipe 1-3 connection, the second main compressor 2 is connected with the second guarantee heat exchanger 4 through the second ventilation pipe 2-3,

The first compressor host 1 is respectively provided with a first air compressor outlet pipe 1-1 and a first air compressor inlet pipe 1-2, and the second compressor host 2 is respectively provided with a second air compressor outlet pipe 2-1 and the second air compressor inlet pipe 2-2,

The first guarantee heat exchanger 3 is provided with a first guarantee heat exchanger outlet pipe 3-1 and a first guarantee heat exchanger inlet pipe 3-2,

The second guarantee heat exchanger 4 is provided with a second guarantee heat exchanger outlet pipe 4-1 and a second guarantee heat exchanger inlet pipe 4-2;

The first air compressor water inlet pipe 1-2, the second air compressor water inlet pipe 2-2, the first guarantee heat exchanger water inlet pipe 3-2 and the second guarantee heat exchanger water inlet pipe 4-2 are all connected with the main water inlet pipe 21 connections;

The first air compressor outlet pipe 1-1 and the second air compressor outlet pipe 2-1 are connected with the air compressor main outlet pipe 22;

The first guarantee heat exchanger outlet pipe 3-1 and the second guarantee heat exchanger outlet pipe 4-1 are connected to the heat exchanger outlet pipe 23,

The outlet pipe 23 of the heat exchanger is connected to the main outlet pipe 22 of the air compressor, and a valve D18 is arranged at the connection.

The hot water cascade utilization device includes four plate heat exchangers, and the plate heat exchangers are connected to the cooling device of the air compressor and the high-temperature hot water end and the low-temperature hot water end through the pipe network. The four heat exchangers are the first plate heat exchanger 5, the second plate heat exchanger 6, the third plate heat exchanger 7, and the fourth plate heat exchanger 8, wherein the first plate heat exchanger 5, the second plate heat exchanger The second plate heat exchanger 6 is connected to the hot spot of high-temperature hot water through pipelines, and the third plate heat exchanger 7 and the fourth plate heat exchanger 8 are connected to the hot spot of low-temperature hot water through pipelines;

The first plate heat exchanger 5 is connected to the main outlet pipe 22 of the air compressor through the second high temperature end heat exchange pipe 5-2, and the second plate heat exchanger 6 is connected to the air compressor through the fifth high temperature end heat exchange pipe 6-2. The total outlet pipe 22 is connected,

The heat exchange pipe 6-2 at the fifth high temperature end is connected to the heat exchange pipe 5-2 at the second high temperature end, which is the heat supply end;

A valve A15 is set on the main water outlet pipe 22 of the air compressor between the second high temperature end heat exchange pipe 5-2 and the fifth high temperature end heat exchange pipe 6-2;

On the main water outlet pipe 22 of the air compressor, between the fifth high temperature end water exchange pipe 6-2 and the second low temperature end water exchange water pipe 7-2, there is a heat exchanger outlet pipe 23 connected with the air compressor main water outlet pipe. 22 valve B16;

The hot end of the first plate heat exchanger 5 is provided with a first high temperature end heat exchange pipe 5-1; the second high temperature end heat exchange pipe 5-3 communicates with the second plate heat exchanger 6 and is connected to the first high temperature end The heat exchange pipe 5-1 is connected, the fourth high temperature end heat exchange pipe 6-1 is connected with the second plate heat exchanger 6, and the first plate heat exchanger 5 is also provided with a sixth high temperature end heat exchange pipe 6-3, The water exchange pipe 6-1 at the fourth high temperature end is in communication with the water exchange pipe 6-3 at the sixth high temperature end, and is used to pass water at a lower temperature to the plate heat exchanger and the hot water sent from the main water outlet pipe of the air compressor Perform heat exchange to ensure the water temperature at the high temperature water end.

The third plate heat exchanger 7, the fourth plate heat exchanger 8 and the pipe network connecting them together constitute the low-temperature hot water utilization part. The third plate heat exchanger 7 passes through the second low-temperature end heat exchange pipe 7-2 and the air pressure The main water outlet pipe 22 of the air compressor is connected, the fourth plate heat exchanger 8 is connected with the main water outlet pipe 22 of the air compressor through the fifth low temperature end water exchange pipe 8-2, the second low temperature end heat exchange pipe 7-2 and the fifth low temperature end The water exchange pipes 8-2 are also connected to each other, and a valve is provided at the position between the fifth low temperature end heat exchange pipe 8-2 and the second low temperature end heat exchange pipe 7-2 on the main water outlet pipe 22 of the air compressor C17,

The third plate heat exchanger 7 is provided with a first low temperature end heat exchange pipe 7-1, the fourth plate heat exchanger 8 is provided with a fourth low temperature end heat exchange pipe 8-1, and the first low temperature end heat exchange pipe 7 -1 communicates with the third low-temperature end heat exchange pipe 7-3 as the outlet point of the low-temperature hot water use end, and the sixth low-temperature end heat exchange pipe 8-3 communicates with the fourth low-temperature end heat exchange pipe 8-1 as a low-temperature heat exchange pipe 8-1. The water inlet end of the water use end sends the cold water from the low-temperature water end to the third plate heat exchanger and the fourth plate heat exchanger, where it becomes usable low-temperature hot water after heat exchange is completed. From the first low-temperature end to the heat exchange pipe 7-1 and the third low-temperature end heat exchange pipe 7-3 flow out for use by users.

The end of the main outlet pipe 22 of the air compressor leads into the shell-and-tube heat exchanger 9, and a valve E19 is set at the position where the main outlet pipe 22 of the air compressor is close to the shell-and-tube heat exchanger 9.

In addition, a water return pipe 9-1 is also provided on the main water outlet pipe 22 of the air compressor. One end of the return water pipe 9-1 is connected to the shell-and-tube heat exchanger 9, and the other end is located at the fifth low-temperature end heat exchange pipe 8-2. The position between the connection point with the main water outlet pipe 22 of the air compressor and the connection point between the water outlet pipe 23 of the heat exchanger and the main water outlet pipe 22 of the air compressor.

The water return pipe 9-1 is connected with the water storage tank 13 through the water storage tank inlet pipe 13-1, and the water storage tank 13 is also connected with the main water inlet pipe 21, and the water storage tank is connected with the softened water device through the softened water inlet pipe 13-2,

The shell-and-tube heat exchanger 9 is connected to the cooling tower 11 through the cooling tower outlet pipe 9-3. In addition, a cooling tower inlet pipe 9-2 is provided between the cooling tower 11 and the shell-and-tube heat exchanger 9. In the cooling tower The water inlet pipe 9-2 is provided with a valve 10.

The control method of the present utility model is specifically implemented according to the following steps,

Step 1, system initialization, start the air compressor heat recovery cascade utilization system, open valve 10, valve A15, valve C17, valve D18, valve E19, pass the tap water through the softening water device 12 to obtain softened water, and then pass through the softened water inlet pipe Lead into the water storage tank 13, and the demineralized water passes through the main water inlet pipe 21 from the water storage tank 13 and then passes into the air compressor cooling device;

Specifically, the demineralized water enters the second air compressor 2 and the first air compressor 1 respectively through the pipeline, and enters the second guarantee heat exchanger 4 and the first guarantee heat exchanger 3 respectively through the pipeline. The valves in the state are: valve 10, valve A15, valve C17, valve D18, valve E19. At this time, the hot water cascade utilization device is not activated. 1 After being discharged from the second air compressor 2, it is collected to the main outlet pipe 22 of the air compressor, and then returns to the shell-and-tube heat exchanger 9 through the pipe and then enters the cooling tower 11;

The demineralized water used for cooling the guarantee heat exchanger is discharged from the first guarantee heat exchanger 3 and the second guarantee heat exchanger 4 and collected in the heat exchanger outlet pipe 23, and then returns to the shell-and-tube heat exchanger 9 Then enter the cooling tower 11; the cooled water enters the shell-and-tube heat exchanger 9 through the 9-2 pipeline and returns to the water storage tank 13, thereby entering the next cycle;

Step 2, open the hot water cascade utilization device, close the valve A15 and the valve C17, the hot water in the main outlet pipe 22 of the air compressor enters the first plate heat exchanger 5 and the second heat exchange pipe 5-2 through the second high temperature end heat exchange pipe 5-2 The two-plate heat exchanger 6 exchanges heat with the water fed into 6-3. After the heat exchange, the hot water enters the air compressor main outlet pipe 22 through the fifth high-temperature end heat exchange pipe 6-2, and then passes through the second low-temperature end pipe 6-2. The end heat exchange pipe 7-2 enters the third plate heat exchanger 7 and the fourth plate heat exchanger 8 to exchange heat with the water passed in 8-3, and the hot water after heat exchange passes through the fifth low temperature end for heat exchange The water pipe 8-2 enters the main water outlet pipe 22 of the air compressor;

When the temperature of the low-temperature hot water in the outlet pipe 23 of the heat exchanger can meet the water temperature requirements of the third plate heat exchanger 7 and the fourth plate heat exchanger 8, close the valve D18 and open the valve B16 to make the heat exchanger outlet The low-temperature hot water in the water pipe 23 is mixed with the high-temperature hot water in the main outlet pipe 22 of the air compressor, and then enters the third plate heat exchanger 7 and the fourth plate heat exchanger 8 through the second low-temperature end heat exchange pipe 7-2. heat exchange;

When the temperature of the low-temperature hot water in the heat exchanger outlet pipe 23 cannot meet the water temperature requirements of the third plate heat exchanger 7 and the fourth plate heat exchanger 8, close the valve B16, open the valve D18, and the heat exchanger outlet pipe The low-temperature hot water in 23 enters the total outlet pipe 22 of the air compressor.

When the water temperature in the main outlet pipe 22 of the air compressor is lower than or equal to the water inlet temperature requirement of the water storage tank 13, close the valve E19 and open the valve F20, so that the hot water in the main outlet pipe 22 of the air compressor is directly discharged from the return pipe 9- 1 and the water storage tank inlet pipe 13-1 enter the water storage tank 13;

When the water temperature in the air compressor main outlet pipe 22 is higher than the water inlet temperature requirement of the water storage tank 13, open the valve E19, close the valve F20, and the water in the air compressor main water outlet pipe 22 enters the shell-and-tube heat exchanger 9 for cooling After cooling down, it enters the water storage tank 13 through the water storage tank water inlet pipe 13-1.

When opening valve E19, according to the size of opening of the water temperature regulation valve 10 in the water storage tank water inlet pipe 13-1, the water temperature in the water storage tank water inlet pipe 13-1 is slightly lower than the water inlet temperature of the water storage tank 13;

When the demineralized water in the water storage tank 13 was lower than the set value, the demineralized water produced by the demineralized water device 12 entered the water storage tank 13 through the demineralized water inlet pipe 13-2 until reaching the water replenishment set value.

Claims (9)

1. an oil free screw air compressor machine recuperation of heat gradient utilization system, it is characterised in that include cooling device of air compressor, hot water cascade utilization device and water softening device (12)；Wherein, cooling device of air compressor mainly includes two compression main frames and two guarantee heat exchangers and water pump, is connected by pipe network between manufacture hot water's cascade utilization device and cooling device of air compressor；Described water softening device (12) is connected with water storage box (13) by softening water water inlet pipe (13-2).

Oil free screw air compressor machine recuperation of heat gradient utilization system the most according to claim 1, it is characterized in that, the structure of described cooling device of air compressor, including the first compression main frame (1) and the second compression main frame (2), with first, the first described compression main frame (1) ensures that heat exchanger (3) is connected by the first breather (1-3), with second, the second described compression main frame (2) ensures that heat exchanger (4) is connected by the second breather (2-3)

It is respectively arranged with the first air compressor machine outlet pipe (1-1) and the first air compressor machine water inlet pipe (1-2) in the first described compression main frame (1), it is respectively arranged with the second air compressor machine outlet pipe (2-1) and the second air compressor machine water inlet pipe (2-2) in the second described compression main frame (2), it is provided with the first guarantee heat exchanger outlet pipe (3-1) and first in the first described guarantee heat exchanger (3) and ensures heat exchanger water inlet pipe (3-2), it is provided with the second guarantee heat exchanger outlet pipe (4-1) and second in the second described guarantee heat exchanger (4) and ensures heat exchanger water inlet pipe (4-2)；Described the first guarantee heat exchanger outlet pipe (3-1) and second ensures that heat exchanger outlet pipe (4-1) is all connected with heat exchanger outlet pipe (23), and described the first air compressor machine water inlet pipe (1-2), the second air compressor machine water inlet pipe (2-2), the first guarantee heat exchanger water inlet pipe (3-2) and the second guarantee heat exchanger water inlet pipe (4-2) are all connected with main water inlet tube (21)；The first described air compressor machine outlet pipe (1-1) and the second air compressor machine outlet pipe (2-1) outlet pipe total with air compressor machine (22) are connected；Described heat exchanger outlet pipe (23) outlet pipe total with air compressor machine (22) is connected, and is provided with valve D (18) in junction.

Oil free screw air compressor machine recuperation of heat gradient utilization system the most according to claim 1, it is characterized in that, described hot water cascade utilization device includes that four plate type heat exchangers, described plate type heat exchanger are connected by pipe network and cooling device of air compressor and high-temperature hot water end (W.E.) and Low Temperature Thermal water end (W.E.)；Four described heat exchangers are the first plate type heat exchanger (5), the second plate type heat exchanger (6), three-plate type heat exchanger (7), the 4th plate type heat exchanger (8) respectively, wherein, first plate type heat exchanger (5), the second plate type heat exchanger (6) are connected with high-temperature-hot-water focus by pipeline, and described three-plate type heat exchanger (7) and the 4th plate type heat exchanger (8) are connected with low-temperature water heating focus by pipeline；Described the first plate type heat exchanger (5) is connected by the second temperature end heat exchanging water pipe (5-2) outlet pipe total with air compressor machine (22), and described the second plate type heat exchanger (6) is connected by the 5th temperature end heat exchanging water pipe (6-2) outlet pipe total with air compressor machine (22)；Described three-plate type heat exchanger (7) is connected by the second low-temperature end heat exchanging water pipe (7-2) and the total outlet pipe of air compressor machine (22), and the 4th described plate type heat exchanger (8) is connected by the 5th low-temperature end heat exchanging water pipe (8-2) outlet pipe total with air compressor machine (22).

Oil free screw air compressor machine recuperation of heat gradient utilization system the most according to claim 3, it is characterised in that described the first plate type heat exchanger (5) be provided with the first temperature end heat exchanging water pipe (5-1) with hot junction；The second described temperature end heat exchanging water pipe (5-3) connects with the second plate type heat exchanger (6), and connect with the first temperature end heat exchanging water pipe (5-1), 4th temperature end heat exchanging water pipe (6-1) connects with the second plate type heat exchanger (6), the 6th temperature end heat exchanging water pipe (6-3) it is additionally provided with on first plate type heat exchanger (5), the 4th described temperature end heat exchanging water pipe (6-1) connects with the 6th temperature end heat exchanging water pipe (6-3), heat exchange is carried out to the hot water sent in outlet pipe total with air compressor machine in plate type heat exchanger for being passed through the water of lower temperature, thus ensure the water temperature of this high temperature water end (W.E.).

Oil free screw air compressor machine recuperation of heat gradient utilization system the most according to claim 4, it is characterised in that both the 5th described temperature end heat exchanging water pipe (6-2) and the second temperature end heat exchanging water pipe (5-2) are connected；The described total outlet pipe of air compressor machine (22) is positioned between the second temperature end heat exchanging water pipe (5-2) and the 5th temperature end heat exchanging water pipe (6-2) and is provided with valve A (15).

Oil free screw air compressor machine recuperation of heat gradient utilization system the most according to claim 3, it is characterized in that, the described total outlet pipe of air compressor machine (22) is positioned between the 5th temperature end heat exchanging water pipe (6-2) and the second low-temperature end heat exchanging water pipe (7-2) and is provided with the valve B (16) being connected to heat exchanger outlet pipe (23) and the total outlet pipe of air compressor machine (22)；The first low-temperature end heat exchanging water pipe (7-1) it is provided with on described three-plate type heat exchanger (7), it is provided with the 4th low-temperature end heat exchanging water pipe (8-1) on the 4th described plate type heat exchanger (8), the first described low-temperature end heat exchanging water pipe (7-1) connects with the 3rd low-temperature end heat exchanging water pipe (7-3), the EXIT POINT of end is used as low-temperature water heating, 6th low-temperature end heat exchanging water pipe (8-3) connects with the 4th low-temperature end heat exchanging water pipe (8-1), the water inlet end of end is used as low-temperature water heating, the cold water of low temperature water end (W.E.) is delivered to three-plate type heat exchanger and the 4th plate type heat exchanger, become, after completing heat exchange wherein, the low-temperature water heating that can use to flow out from the first low-temperature end heat exchanging water pipe (7-1) and the 3rd low-temperature end heat exchanging water pipe (7-3), for user.

Oil free screw air compressor machine recuperation of heat gradient utilization system the most according to claim 6, it is characterized in that, also being interconnected between described the second low-temperature end heat exchanging water pipe (7-2) and the 5th low-temperature end heat exchanging water pipe (8-2), the position being positioned between the 5th low-temperature end heat exchanging water pipe (8-2) and the second low-temperature end heat exchanging water pipe (7-2) on the total outlet pipe of air compressor machine (22) is provided with valve C (17).

8. according to the oil free screw air compressor machine recuperation of heat gradient utilization system described in any one in claim 2～7, it is characterized in that, end access tube shell heat exchanger (9) of the total outlet pipe of described air compressor machine (22), at the described total outlet pipe of air compressor machine (22), the position of shell-and-tube heat exchanger (9) is provided with valve E (19), the total outlet pipe of air compressor machine (22) is additionally provided with return pipe (9-1), one end of described return pipe (9-1) is connected with shell-and-tube heat exchanger (9), the other end is positioned at the position between the 5th low-temperature end heat exchanging water pipe (8-2) and the junction point of the junction point of the total outlet pipe of air compressor machine (22) and heat exchanger outlet pipe (23) and the total outlet pipe of air compressor machine (22).

Oil free screw air compressor machine recuperation of heat gradient utilization system the most according to claim 8, it is characterized in that, described return pipe (9-1) is connected with water storage box (13) by water storage box water inlet pipe (13-1), described water storage box (13) is also associated with main water inlet tube (21), described water storage box is connected with water softening device by softening water water inlet pipe (13-2), described shell-and-tube heat exchanger (9) is connected with cooling tower (11) by cooling tower outlet pipe (9-3), between cooling tower (11) and shell-and-tube heat exchanger (9), additionally it is additionally provided with cooling tower water inlet pipe (9-2), cooling tower water inlet pipe (9-2) is provided with valve (10).