Built-in heat recovery system

Abstract

The embodiment of the invention provides a built-in heat recovery system which comprises a compressor main machine, an oil-gas mixture outlet of the compressor main machine communicates with a gas inlet of an oil-gas separator, a gas outlet of the oil-gas separator communicates with an external gas using end, and a bottom oil outlet of the oil-gas separator communicates with an oil inlet of the compressor main machine through an oil return pipeline; a first temperature control valve, a heat recovery heat exchanger, a second temperature control valve and an oil cooler are arranged on the oil return pipeline, a water outlet of the heat recovery heat exchanger is communicated to an external heat utilization end, and heat in the lubricating oil can be recycled while the lubricating oil is cooled; during transformation, only one heat recovery heat exchanger and a corresponding temperature control valve need to be additionally arranged on an original oil return pipeline, the pipeline is simple, the occupied area is small, and the investment cost is low; and no matter whether a user uses heat recovery or not, normal operation of the compressor unit is not affected.

Description

Technical Field

[0001] The invention relates to the technical field of air compressors, and in particular to a built-in heat recovery system. Background Art

[0002] The working process of the current screw air compressor is as follows: after the dust and other impurities in the atmosphere are filtered out by the air intake filter, the air enters the compressor main unit through the air intake valve, and is mixed with the injected cooling lubricating oil during the compression process to form an oil-gas mixture. The compressed oil-gas mixture is discharged into the oil-gas separator, and is separated by the oil-gas separator to obtain high-temperature and high-pressure lubricating oil and compressed air. Due to the operating temperature requirements of the machine, these high-temperature and high-pressure lubricating oil and compressed air must be sent to their respective cooling systems for cooling. The compressed air is cooled by the aftercooler and then sent to the air end, while the high-temperature lubricating oil is cooled by the oil cooler and then sent back to the compressor main unit to enter the next cycle.

[0003] Existing air compressors generally have an oil cooler installed inside the unit to cool the lubricating oil. The heat obtained during the heat exchange process is directly discharged into the atmosphere, wasting a lot of heat energy. As the national energy efficiency requirements become increasingly stringent, customers have an increasing demand for heat recovery in air compressors. Generally, companies will choose to install a heat recovery device independent of the air compressor unit outside the air compressor to recover heat, which occupies a large area and requires a substantial transformation of the existing air compressor. After the transformation, the pipelines are complex and the transformation investment is large. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a built-in heat recovery system to solve the technical problems that an independent heat recovery device is provided outside the air compressor, which occupies a large area, has complex pipelines after modification, and requires a large modification investment.

[0005] An embodiment of the present invention provides a built-in heat recovery system, comprising a compressor main unit, wherein the oil-gas mixed gas outlet of the compressor main unit is connected to the air inlet of an oil-gas separator, the air outlet of the oil-gas separator is connected to an external gas end, and the bottom oil outlet of the oil-gas separator is connected to the oil inlet of the compressor main unit through an oil return pipeline; a first temperature control valve, a heat recovery heat exchanger, a second temperature control valve and an oil cooler are arranged on the oil return pipeline, the first temperature control valve and the second temperature control valve are both two-position three-way solenoid valves with one inlet and two outlets, a lubricating oil passage and a cooling medium passage are arranged in the heat recovery heat exchanger and the oil cooler, the lubricating oil passage is provided with an oil inlet and an oil outlet, and the cooling medium passage is provided with a water inlet and a water outlet;

[0006] The inlet of the first temperature control valve is connected to the oil-gas separator, one of the outlets of the first temperature control valve is connected to the inlet of the second temperature control valve, and the other outlet of the first temperature control valve is connected to the oil inlet of the heat recovery heat exchanger; the oil outlet of the heat recovery heat exchanger is connected between the first temperature control valve and the second temperature control valve, and the water outlet of the heat recovery heat exchanger is connected to the external hot end through the water outlet pipeline; one of the outlets of the second temperature control valve is connected to the compressor host, and the other outlet of the second temperature control valve is connected to the oil inlet of the oil cooler, and the oil outlet of the oil cooler is connected between the second temperature control valve and the compressor host;

[0007] When the temperature of the lubricating oil flowing through the first temperature control valve is lower than its preset working temperature, the first temperature control valve is connected to the second temperature control valve; when the temperature of the lubricating oil flowing through the first temperature control valve is higher than its preset working temperature, the first temperature control valve is connected to the heat recovery heat exchanger;

[0008] When the temperature of the lubricating oil flowing through the second temperature control valve is lower than its preset working temperature, the second temperature control valve is connected to the compressor main engine; when the temperature of the lubricating oil flowing through the second temperature control valve is higher than its preset working temperature, the second temperature control valve is connected to the oil cooler.

[0009] Optionally, an operating temperature of the first temperature control valve is lower than an operating temperature of the second temperature control valve.

[0010] Optionally, a stop valve is provided on the water outlet pipe of the heat recovery heat exchanger.

[0011] Optionally, the heat recovery heat exchanger is a plate heat exchanger.

[0012] Optionally, an oil filter is provided between the second temperature control valve and the compressor main unit, and the oil outlet of the oil cooler is connected between the second temperature control valve and the oil filter.

[0013] Optionally, an aftercooler is provided between the oil-gas separator and the external air end, and a compressed air passage and a cooling water passage are provided in the aftercooler; the compressed air passage is provided with an air inlet connected to the oil-gas separator and an air outlet connected to the external air end; the cooling water passage is provided with a water inlet and a water outlet, the water inlet of the cooling water passage is connected to an external cooling water circulation pipeline, the water outlet of the cooling water passage is connected to the water inlet of the oil cooler, and the water outlet of the oil cooler is connected to the external cooling water circulation pipeline.

[0014] The embodiments of the present invention have the following beneficial effects:

[0015] 1. A heat recovery heat exchanger is added between the oil-gas separator and the oil cooler, and the cooling passage of the lubricating oil is automatically adjusted by the first temperature control valve and the second temperature control valve. The heat in the lubricating oil can be recovered and utilized while cooling the lubricating oil. The heat recovery efficiency is high. After the heat is recovered, the unit will not operate in a high temperature environment, and the performance of the unit can be better guaranteed. In addition, during the transformation, only a heat recovery heat exchanger and a corresponding temperature control valve need to be added to the original return oil pipeline. The pipeline is simple, the footprint is small, and the investment cost is low.

[0016] 2. The working temperature of the first temperature control valve is lower than that of the second temperature control valve. When the user uses the heat recovery heat exchanger to cool and recover the lubricating oil, the cooled lubricating oil can be directly returned to the compressor host without passing through the oil cooler; when the user chooses not to use heat recovery, the cooling medium in the heat recovery heat exchanger does not participate in the heat exchange, and the heat recovery heat exchanger can be used as a normal lubricating oil passage, and the lubricating oil is cooled by the oil cooler; whether the user uses heat recovery or not, it will not affect the normal operation of the compressor unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 is a system flow chart of an embodiment of the present invention;

[0019] The numbers in the figure represent:

[0020] 1. Compressor main unit; 2. Oil-gas separator; 3. First temperature control valve; 4. Heat recovery heat exchanger; 5. Second temperature control valve; 6. Oil cooler; 7. Oil filter; 8. Aftercooler. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0022] like Figure 1As shown, an embodiment of the present invention provides a built-in heat recovery system, including a compressor main unit 1, the oil-gas mixture outlet of the compressor main unit 1 is connected to the air inlet of the oil-gas separator 2, and the air outlet of the oil-gas separator 2 is connected to the external gas end to transport the separated compressed gas to the external gas end; the bottom oil outlet of the oil-gas separator 2 is connected to the oil inlet of the compressor main unit 1 through the oil return pipeline to send the separated lubricating oil back to the compressor main unit 1 for recycling.

[0023] The return oil pipeline is provided with a first temperature control valve 3, a heat recovery heat exchanger 4, a second temperature control valve 5 and an oil cooler 6. The first temperature control valve 3 and the second temperature control valve 5 are both two-position three-way solenoid valves with one inlet and two outlets. The heat recovery heat exchanger 4 and the oil cooler 6 are both provided with a lubricating oil passage and a cooling medium passage for heat exchange with the lubricating oil passage. The lubricating oil passage is provided with an oil inlet and an oil outlet, and the cooling medium passage is provided with a water inlet and a water outlet.

[0024] Among them, the inlet of the first temperature control valve 3 is connected to the oil-gas separator 2, one of the outlets of the first temperature control valve 3 is connected to the inlet of the second temperature control valve 5, and the other outlet of the first temperature control valve 3 is connected to the oil inlet of the heat recovery heat exchanger 4. The oil outlet of the heat recovery heat exchanger 4 is connected between the first temperature control valve 3 and the second temperature control valve 5, the water inlet of the heat recovery heat exchanger 4 is connected to the external cooling medium pipeline, and the water outlet is connected to the external heat end through the water outlet pipeline, so that the user can recycle the heat in the lubricating oil. Furthermore, a stop valve can be set on the outlet pipeline of the heat recovery heat exchanger 4 so that the user can choose whether to use heat recovery. The heat recovery heat exchanger 4 is preferably a plate heat exchanger, which has high heat exchange efficiency, low heat loss, compact structure, small footprint, and long service life.

[0025] One outlet of the second temperature control valve 5 is connected to the compressor host 1, and the other outlet of the second temperature control valve 5 is connected to the oil inlet of the oil cooler 6, and the oil outlet of the oil cooler 6 is connected between the second temperature control valve 5 and the compressor host 1. Specifically, an oil filter 7 for removing impurities in the lubricating oil is provided between the second temperature control valve 5 and the compressor host 1, and the oil outlet of the oil cooler 6 is connected between the second temperature control valve 5 and the oil filter 7.

[0026] In addition, an aftercooler 8 for cooling the compressed air is provided between the oil-gas separator 2 and the external air end. A compressed air passage and a cooling water passage are provided in the aftercooler 8. The compressed air passage is provided with an air inlet connected to the oil-gas separator 2 and an air outlet connected to the external air end, and the cooling water passage is provided with a water inlet and a water outlet. The water inlet of the cooling water passage of the aftercooler 8 can be connected to the external cooling water circulation pipeline, the water outlet can be connected to the water inlet of the oil cooler 6, and the water outlet of the oil cooler 6 can be connected to the external cooling water circulation pipeline to circulate the cooling water.

[0027] When the temperature of the lubricating oil flowing through the first temperature control valve 3 is lower than its preset working temperature, the first temperature control valve 3 is connected with the second temperature control valve 5, and the lubricating oil does not need to enter the heat recovery heat exchanger 4, and directly flows into the second temperature control valve 5 through the first temperature control valve 3. When the temperature of the lubricating oil flowing through the first temperature control valve 3 is higher than its preset working temperature, the first temperature control valve 3 is connected with the heat recovery heat exchanger 4, and the lubricating oil enters the heat recovery heat exchanger 4 through the first temperature control valve 3, and then flows into the second temperature control valve 5 after heat exchange and cooling in the heat recovery heat exchanger 4. When the temperature of the lubricating oil flowing through the second temperature control valve 5 is lower than its preset working temperature, the second temperature control valve 5 is connected with the compressor main unit 1, and the lubricating oil does not need to enter the oil cooler 6, and directly flows into the compressor main unit 1 through the second temperature control valve 5. When the temperature of the lubricating oil flowing through the second temperature control valve 5 is higher than its preset working temperature, the second temperature control valve 5 is connected with the oil cooler 6, and the lubricating oil enters the oil cooler 6 through the second temperature control valve 5, and then flows into the compressor main unit 1 after heat exchange and cooling in the oil cooler 6.

[0028] Furthermore, the working temperature of the first temperature control valve 3 is lower than the working temperature of the second temperature control valve 5. When the user uses the heat recovery heat exchanger 4 to cool and recover the lubricating oil, if the temperature of the lubricating oil after cooling is lower than the preset working temperature of the second temperature control valve 5, the lubricating oil can be directly returned to the compressor main unit 1 without passing through the oil cooler 6; if the temperature of the lubricating oil after cooling is still higher than the preset working temperature of the second temperature control valve 5, the lubricating oil will flow into the compressor main unit 1 after secondary cooling through the oil cooler 6, ensuring that the unit will not operate in a high temperature environment. When the user closes the stop valve and chooses not to use heat recovery, the cooling medium in the heat recovery heat exchanger 4 does not participate in the heat exchange, and the heat recovery heat exchanger 4 can be used as a normal lubricating oil passage, and the lubricating oil is only cooled by the oil cooler 6. In other words, whether the user uses heat recovery or not, the lubricating oil can be cooled and cooled, and the normal operation of the compressor unit will not be affected.

[0029] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present invention. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A built-in heat recovery system, comprising a compressor mainframe, wherein the oil-gas mixture outlet of the compressor mainframe is connected to the air inlet of an oil-gas separator, the air outlet of the oil-gas separator is connected to an external air end, and the bottom oil outlet of the oil-gas separator is connected to the oil inlet of the compressor mainframe through an oil return pipeline; characterized in that: The oil return pipeline is provided with a first temperature control valve, a heat recovery heat exchanger, a second temperature control valve and an oil cooler, the first temperature control valve and the second temperature control valve are two-position three-way solenoid valves with one inlet and two outlets, the heat recovery heat exchanger and the oil cooler are both provided with a lubricating oil passage and a cooling medium passage, the lubricating oil passage is provided with an oil inlet and an oil outlet, and the cooling medium passage is provided with a water inlet and a water outlet; The inlet of the first temperature control valve is connected to the oil-gas separator, one of the outlets of the first temperature control valve is connected to the inlet of the second temperature control valve, and the other outlet of the first temperature control valve is connected to the oil inlet of the heat recovery heat exchanger; the oil outlet of the heat recovery heat exchanger is connected between the first temperature control valve and the second temperature control valve, and the water outlet of the heat recovery heat exchanger is connected to the external hot end through the water outlet pipeline; one of the outlets of the second temperature control valve is connected to the compressor host, and the other outlet of the second temperature control valve is connected to the oil inlet of the oil cooler, and the oil outlet of the oil cooler is connected between the second temperature control valve and the compressor host; When the temperature of the lubricating oil flowing through the first temperature control valve is lower than its preset working temperature, the first temperature control valve is connected to the second temperature control valve; when the temperature of the lubricating oil flowing through the first temperature control valve is higher than its preset working temperature, the first temperature control valve is connected to the heat recovery heat exchanger; When the temperature of the lubricating oil flowing through the second temperature control valve is lower than its preset working temperature, the second temperature control valve is connected to the compressor main engine; when the temperature of the lubricating oil flowing through the second temperature control valve is higher than its preset working temperature, the second temperature control valve is connected to the oil cooler.

2. A built-in heat recovery system according to claim 1, characterized in that: The operating temperature of the first temperature control valve is lower than the operating temperature of the second temperature control valve.

3. A built-in heat recovery system according to claim 2, characterized in that: A stop valve is arranged on the water outlet pipeline of the heat recovery heat exchanger.

4. The built-in heat recovery system according to claim 1, characterized in that: The heat recovery heat exchanger is a plate heat exchanger.

5. The built-in heat recovery system according to claim 1, characterized in that: An oil filter is arranged between the second temperature control valve and the compressor main engine, and the oil outlet of the oil cooler is connected between the second temperature control valve and the oil filter.

6. The built-in heat recovery system according to claim 1, characterized in that: An aftercooler is provided between the oil-gas separator and the external air end, and a compressed air passage and a cooling water passage are provided in the aftercooler; the compressed air passage is provided with an air inlet connected to the oil-gas separator and an air outlet connected to the external air end; the cooling water passage is provided with a water inlet and a water outlet, the water inlet of the cooling water passage is connected to the external cooling water circulation pipeline, the water outlet of the cooling water passage is connected to the water inlet of the oil cooler, and the water outlet of the oil cooler is connected to the external cooling water circulation pipeline.

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