A coupled energy-saving system

Abstract

The present invention discloses a coupled energy-saving system, including a natural gas internal combustion engine distributed energy system and a natural gas steam boiler system, which are coupled through a stratified water tank, a remote liquid level gauge is provided in the stratified water tank, the natural gas internal combustion engine distributed energy system includes an internal combustion generator set, a first heat exchanger, an emergency radiator and a second heat exchanger, the first heat exchanger cools the flue gas, the emergency radiator and the second heat exchanger form a cooling cycle of the cylinder of the internal combustion generator set, the natural gas steam boiler system includes a natural gas boiler, a third heat exchanger, a drain device, an iron ion removal device, a water softener and a softening water tank, and tap water is respectively connected to the water inlet end and the water softener of the fourth heat exchanger arranged in the stratified water tank through a first three-way valve, and the water outlet end of the fourth heat exchanger is connected to the water softener. The present invention uses hot water generated by the waste heat of the internal combustion engine to heat the steam boiler to replenish water, reduces the overflow water temperature, reduces the waste of heat energy, reduces the boiler gas consumption rate, and improves the energy efficiency of the overall system.

Description

Technical Field

[0001] The invention relates to the field of heating, and in particular to a coupled energy-saving system. Background Art

[0002] In enterprises, various energy demands often exist simultaneously according to production and living needs. Based on load analysis and matching, energy stations are constructed from the perspective of efficient energy utilization. When there are certain electricity loads, hot water heating loads, and steam loads, the following are some of the energy demands:

[0003] A natural gas internal combustion engine distributed energy system is set up, and a suitable natural gas internal combustion engine unit is selected to supply power according to electricity consumption and hot water load. The internal combustion engine flue gas and cylinder jacket water are exchanged to generate hot water for heating. A natural gas steam boiler is set up to supply steam according to the steam load. At present, the two systems are independent of each other and have no connection.

[0004] However, natural gas internal combustion engine units can only achieve higher energy efficiency when operating near full load conditions. To ensure efficient operation, the units are best operated at full load, at which time the power supply and hot water supply capacity of the units are basically fixed.

[0005] However, load demand often fluctuates, and there is often a situation where electricity can be fully absorbed, but the demand for waste heat hot water is insufficient and cannot be fully absorbed.

[0006] The make-up water temperature of a natural gas steam boiler is room temperature. If the make-up water temperature is increased, the gas consumption of the natural gas boiler itself can be reduced.

[0007] Therefore, how to couple the two to achieve energy saving is a difficult problem.

[0008] In addition, after the natural gas in the natural gas steam boiler is burned in the boiler furnace and produces steam through heat exchange, the flue gas is discharged from the chimney through the flue. The exhaust temperature of the natural gas boiler is about 150°C, which is a low-temperature waste heat resource. We should make use of it. Summary of the invention

[0009] In order to solve the above problems, the present invention provides a coupled energy-saving system, which uses hot water generated by the waste heat of the internal combustion engine to heat the steam boiler replenishment water, thereby reducing the overflow water temperature, reducing heat energy waste, reducing the boiler gas consumption rate, and improving the energy efficiency of the overall system.

[0010] In addition, the application of stratified water tanks reduces the floor space and realizes the connection between high and low temperature water tanks at the same time. The total volume of high and low temperature water tanks remains unchanged, the overall adjustment ability is strong, and the production cost is reduced.

[0011] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a coupled energy-saving system, including a natural gas internal combustion engine distributed energy system and a natural gas steam boiler system, the two are coupled through a stratified water tank, the stratified water tank is provided with a remote liquid level gauge, the natural gas internal combustion engine distributed energy system includes an internal combustion generator set, a first heat exchanger, an emergency radiator and a second heat exchanger, the first heat exchanger cools the flue gas discharged by the internal combustion generator set, the cylinder outlet of the internal combustion generator set is connected to the second heat exchanger through a second three-way valve, and the second heat exchanger is connected through The third three-way valve is connected to the inlet of the cylinder of the internal combustion generator set. The emergency radiator is arranged between the second three-way valve and the third three-way valve. The emergency radiator and the second heat exchanger form a cooling cycle for the cylinder of the internal combustion generator set. The natural gas steam boiler system includes a natural gas boiler, a third heat exchanger, a drain device, an iron ion removal device, a water softener and a softened water tank. The third heat exchanger is arranged on the flue of the natural gas boiler. The third heat exchanger is connected to the drain device, the iron ion removal device, the water softener and the softened water tank in sequence; the tap water is respectively The water inlet end of the fourth heat exchanger arranged in the stratified water tank is connected to the water softener, and the water outlet end of the fourth heat exchanger is connected to the water softener; the stratified water tank is an integrated water tank structure, including a water tank body, the water tank body is a three-layer structure, the upper side is a high-temperature water tank, the lower side is a low-temperature water tank, and the middle is a partition layer, the high-temperature water tank is provided with a high-temperature water inlet and a high-temperature water outlet at the upper and lower offsets of its opposite end corners, and the high-temperature water inlet is located on the upper side, and the low-temperature water tank is provided with a low-temperature water inlet and a low-temperature water outlet at the upper and lower offsets of its opposite end corners, and the low-temperature water inlet is located on the upper side, and On the same side as the high-temperature water inlet, the partition layer includes an upper partition and a lower partition, the upper partition is provided with an upper partition opening near the high-temperature water outlet, and the lower partition is provided with a lower partition opening near the low-temperature water inlet; the water flow outlet of the first heat exchanger is connected to the high-temperature water inlet, and the high-temperature water outlet is connected to the fifth heat exchanger water inlet through a heating circulation water pump, the fifth heat exchanger water outlet is connected to the low-temperature water inlet, and the low-temperature water outlet is connected to the first heat exchanger water inlet through a heating circulation water pump; a water supply pump is provided between the softening water tank and the third heat exchanger.

[0012] Furthermore, the upper partition opening and the lower partition opening are both isosceles right triangle openings, and the waist length thereof is 400-600 mm.

[0013] Furthermore, the fourth heat exchanger and the remote liquid level gauge are both arranged in the high-temperature water tank.

[0014] Furthermore, an overflow port is provided on the upper side of the stratified water tank.

[0015] Furthermore, the natural gas boiler flue gas is discharged from the chimney after heat exchange in the third heat exchanger.

[0016] Furthermore, the drain device recovers the condensed water from the third heat exchanger and transmits it to the softened water tank. The water in the softened water tank is heated by the third heat exchanger and then transmitted to the natural gas boiler for reuse.

[0017] Furthermore, the internal combustion generator set is a 400kw internal combustion generator set, the first heat exchanger is a 230kw flue gas hot water heat exchanger, the second heat exchanger is a 240kw plate heat exchanger; the third heat exchanger is a flue gas hot water heat exchanger, the fourth heat exchanger is a coil heat exchanger, and the fifth heat exchanger is a heating heat exchanger.

[0018] In summary, the present invention has the following advantages:

[0019] The present invention utilizes hot water generated by waste heat from an internal combustion engine to heat supplementary water for a steam boiler, thereby reducing the overflow water temperature, reducing heat energy waste, reducing boiler gas consumption rate, and improving the energy efficiency of the overall system.

[0020] In addition, the application of stratified water tanks reduces the floor space and realizes the connection between high and low temperature water tanks at the same time. The total volume of high and low temperature water tanks remains unchanged, the overall adjustment ability is strong, and the production cost is reduced.

[0021] In the natural gas steam boiler system, the exhaust temperature of flue gas is greatly reduced to achieve deep utilization of flue gas waste heat. At the same time, the condensed water is recycled and returned to the boiler, which has a higher overall utilization rate and can reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the present invention;

[0023] Figure 2 It is a schematic diagram of the stratified water tank structure. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Example 1

[0025] A coupled energy-saving system, such as Figure 1 As shown, it includes a natural gas internal combustion engine distributed energy system and a natural gas steam boiler system, which are coupled through a stratified water tank 6. A remote liquid level meter 9 is provided in the stratified water tank 6, and the remote liquid level meter is connected to the control system.

[0026] For details, please refer to the attached Figure 1The natural gas internal combustion engine distributed energy system includes an internal combustion generator set 1, a first heat exchanger 2, an emergency radiator 3 and a second heat exchanger 4. The first heat exchanger 2 cools the flue gas, and the emergency radiator 3 and the second heat exchanger 4 form a cooling cycle for the cylinder of the internal combustion generator set 1. In the cooling cycle, the cylinder cooling water inlet temperature is 84°C, that is, the water outlet at the rear end of the emergency radiator is 84°C. After cooling the cylinder, the temperature rises and the water outlet temperature is 92°C.

[0027] When the waste heat is utilized, the outlet water passes through the three-way valve, and the 92°C water enters the second heat exchanger 4 to heat the low-temperature side water, thereby reducing the temperature.

[0028] The control system uses a three-way valve and an emergency radiator to control the water temperature to drop to 84°C before continuing to circulate in the internal combustion engine cylinders.

[0029] At the second heat exchanger, the low-temperature side water is heated from 55°C to 75°C and then enters the stratified water tank.

[0030] At the same time, the combustion and expansion of the internal combustion generator set drives the generator to generate electricity. The flue gas temperature after combustion is 451°C. The high-temperature flue gas passes through the first heat exchanger to heat the water. The water temperature is heated from 55°C to 75°C. The flue gas temperature is reduced and discharged through the chimney, and the 75°C hot water is combined and enters the stratified water tank.

[0031] Continue to refer to the attached Figure 1 The natural gas steam boiler system includes a natural gas boiler 11, a third heat exchanger 12, a drain device 14, an iron ion removal device 15, a water softener 16 and a softened water tank 17. The tap water is connected to the water inlet end of the fourth heat exchanger 10 and the water softener 16 arranged in the stratified water tank 6 through a first three-way valve 19, and the water outlet end of the fourth heat exchanger 10 is connected to the water softener 16.

[0032] In the operation mechanism of the natural gas steam boiler system itself, natural gas is burned in the natural gas boiler 11 and then discharged into the atmosphere through the flue. The flue gas temperature is 150°C, and the third heat exchanger 12 on the flue reduces the flue gas from 150°C to 50°C and discharges it from the chimney 13. That is, the flue gas from the natural gas boiler 11 is discharged from the chimney 13 after heat exchange through the third heat exchanger 12, and the temperature is 50°C.

[0033] During the flue gas cooling process, the water vapor contained therein will condense and release the latent heat of vaporization. A drain device is set at the bottom of the heat exchanger to recover the condensed water. The condensed water pipeline is deironed by the deironing device, and then the water inlet pipe of the water softener and the boiler feed water are softened and discharged into the softened water tank 5.

[0034] The softened water in the softened water tank is pumped by a water supply pump 18 through a water channel of a heat exchanger and then heated by waste heat of flue gas and then sent to the natural gas boiler 11 .

[0035] In order to realize the coupling between the two, please refer to the attached Figure 2 The layered water tank 6 is an integrated water tank structure, including a water tank body 61, which is a three-layer structure, with a high-temperature water tank 611 on the upper side, a low-temperature water tank 612 on the lower side, and a separation layer 613 in the middle.

[0036] The high-temperature water tank 611 is provided with a high-temperature water inlet 6111 and a high-temperature water outlet 6112 at the opposite end corners, and the high-temperature water inlet 6111 is located on the upper side. The low-temperature water tank 612 is provided with a low-temperature water inlet 6121 and a low-temperature water outlet 6122 at the opposite end corners, and the low-temperature water inlet 6121 is located on the upper side and on the same side as the high-temperature water inlet 6111.

[0037] The partition layer 613 includes an upper partition 6131 and a lower partition 6132 . The upper partition 6131 is provided with an upper partition opening 62 near the high-temperature water outlet 6112 , and the lower partition 6132 is provided with a lower partition opening 63 near the low-temperature water inlet 6112 of the water tank body 61 .

[0038] In terms of the connection mechanism, the water outlet of the first heat exchanger 2 is connected to the high-temperature water inlet 6111, the high-temperature water outlet 6112 is connected to the water inlet of the fifth heat exchanger 8 through the heating circulation water pump 7, the water outlet of the fifth heat exchanger 8 is connected to the low-temperature water inlet 6121, and the low-temperature water outlet 6122 is connected to the water inlet of the first heat exchanger 2 through the heating circulation water pump 5.

[0039] Moreover, the upper partition opening 2 and the lower partition opening 3 are both isosceles right triangle openings, and the waist length thereof is 400-600 mm.

[0040] The fourth heat exchanger 10 and the remote liquid level gauge 9 are both arranged in the high-temperature water tank 611 , and an overflow port is also provided on the upper side of the stratified water tank 6 .

[0041] In the tap water inlet setting, 20°C tap water can be raised to 25°C through the first three-way valve 19 and the fourth heat exchanger, and then enters the softener together with the condensed water and enters the softened water tank after being softened, effectively reducing the gas consumption rate and achieving energy saving.

[0042] Specifically, under the action of the remote liquid level gauge, when the liquid level is 15 cm lower than the overflow port liquid level, the first three-way valve is controlled to switch the tap water to directly enter the water softener.

[0043] When excessive high-temperature water overflows, when the liquid level in the stratified water tank reaches the overflow level, the three-way valve is controlled to switch the tap water through the fourth heat exchanger. After heating, the tap water temperature rises from 20°C to 25°C, and then enters the water softener. At the same time, the overflow water temperature is reduced.

[0044] In this way, when hot water cannot be fully utilized, the temperature of the make-up water for the natural gas steam boiler increases, the gas consumption rate decreases, and the overall energy efficiency of the system is improved.

[0045] Further explanation of the natural gas steam boiler system in combination with the recovery and utilization of waste heat from natural gas combustion flue gas:

[0046] Serial number Analyze Project percentage% 1 CH4 93.5827% 2 C2H6 4.9946% 3 C3H8 0.4703% 4 iC4H10 0.0818% 5 nC4H10 0.1085% 6 iC5H12 0.0150% 7 nC5H12 0.0086% 8 C6 0.0072% 9 N2 0.5477% 10 CO2 0.1809% 11 H2S 0.6600% 12 High calorific value 38659Kj / Nm3) 13 Low calorific value 34793Kj / Nm3)

[0047] Table 1: Boiler natural gas composition analysis table

[0048] The combustion of 1Nm3 of natural gas requires 10.89Nm3 of air and generates a flue gas volume of 11.91Nm3, of which the volume of water vapor is 2.04Nm3, the volume of dry flue gas is 9.87Nm3, and the mass of water vapor is 1.64kg.

[0049] After using the heat exchanger, the flue gas is cooled to 50℃, and 0.565kg of water vapor is condensed.

[0050] Dry flue gas releases 1358kJ of heat, water vapor releases 1659.28kJ of heat, 3088kJ of recoverable heat, and 0.565kg of recoverable condensed water.

[0051] The energy saving and consumption reduction is analyzed, taking a 3t / h natural gas boiler as an example:

[0052] Vertical natural gas boiler 3t / h, steam parameters 0.8MPa, 175℃, enthalpy 2773kJ / kg, boiler efficiency 92%, exhaust temperature 150℃, boiler natural gas consumption rate 84Nm3 / t, natural gas boiler excess air coefficient 1.1, boiler feed water temperature 20℃.

[0053] According to the analysis of the boiler heat balance equation, the natural gas consumption rate of the boiler after flue gas waste heat is 76.77Nm3 / t, the steam consumption rate decreases by 8.6%, and 130kg / h of condensed water can be recovered.

[0054] It is worth mentioning that the internal combustion generator set 1 is a 400kw internal combustion generator set, the first heat exchanger 2 is a 230kw flue gas hot water heat exchanger, the second heat exchanger 4 is a 240kw plate heat exchanger; the third heat exchanger 12 is a flue gas hot water heat exchanger, the fourth heat exchanger 10 is a coil heat exchanger, and the fifth heat exchanger 8 is a heating heat exchanger.

[0055] In summary, using the hot water generated by the waste heat of the internal combustion engine to heat the steam boiler make-up water can reduce the overflow water temperature, reduce heat energy waste, reduce the boiler gas consumption rate, and improve the energy efficiency of the overall system.

[0056] In addition, the application of stratified water tanks reduces the floor space and realizes the connection between high and low temperature water tanks at the same time. The total volume of high and low temperature water tanks remains unchanged, the overall adjustment ability is strong, and the production cost is reduced.

[0057] In the natural gas steam boiler system, the exhaust temperature of flue gas is greatly reduced to achieve deep utilization of flue gas waste heat. At the same time, the condensed water is recycled and returned to the boiler, which has a higher overall utilization rate and can reduce costs.

[0058] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0059] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0060] For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] It should be understood that the above-mentioned embodiments are merely illustrative and not restrictive. Without departing from the basic principles of the present invention, various obvious or equivalent modifications or substitutions that can be made by those skilled in the art to the above-mentioned details will all be included in the scope of the claims of the present invention.

Claims

1. A coupled energy-saving system, characterized in that: The invention comprises a natural gas internal combustion engine distributed energy system and a natural gas steam boiler system, the two being coupled via a stratified water tank (6), the stratified water tank (6) being provided with a remote liquid level gauge (9), the natural gas internal combustion engine distributed energy system comprising an internal combustion generator set (1), a first heat exchanger (2), an emergency radiator (3) and a second heat exchanger (4), the first heat exchanger (2) cooling the flue gas discharged by the internal combustion generator set (1), the cylinder outlet of the internal combustion generator set (1) being connected to the second heat exchanger (4) via a second three-way valve, the second heat exchanger (4) being connected to the cylinder inlet of the internal combustion generator set (1) via a third three-way valve, the emergency radiator (3) being arranged between the second three-way valve and the third three-way valve, the emergency radiator (3) being arranged between the second three-way valve and the third three-way valve, the emergency radiator (4) being arranged between the second three-way valve and the third three-way valve, the emergency radiator (3 ... The radiator (3) and the second heat exchanger (4) form a cooling cycle for the cylinder of the internal combustion generator set (1); the natural gas steam boiler system comprises a natural gas boiler (11), a third heat exchanger (12), a drain device (14), an iron ion removal device (15), a water softener (16) and a softened water tank (17); the third heat exchanger (12) is arranged on the flue of the natural gas boiler (11); the third heat exchanger (12) is connected to the drain device (14), the iron ion removal device (15), the water softener (16) and the softened water tank (17) in sequence; tap water is respectively connected to the water inlet end of the fourth heat exchanger (10) arranged in the stratified water tank (6) and the water softener (16) through a first three-way valve (19); the fourth heat exchanger (10) is connected to the water inlet end of the fourth heat exchanger (10) and the water softener (16) through a first three-way valve (19); the fourth heat exchanger (10) is connected to the water inlet end of the fourth heat exchanger (10) and the water softener (16) respectively. The water outlet end of the device (10) is connected to the water softener (16); the stratified water tank (6) is an integrated water tank structure, comprising a water tank body (61); the water tank body (61) is a three-layer structure, the upper side is a high-temperature water tank (611), the lower side is a low-temperature water tank (612), and the middle is a partition layer (613); the high-temperature water tank (611) is provided with a high-temperature water inlet (6111) and a high-temperature water outlet (6112) at its opposite end corners, the high-temperature water inlet (6111) is located on the upper side; the low-temperature water tank (612) is provided with a low-temperature water inlet (6121) and a low-temperature water outlet (6122) at its opposite end corners, the low-temperature water inlet (6121) is located on the upper side and is in contact with the high-temperature water inlet (6111). On the same side, the partition layer (613) comprises an upper partition (6131) and a lower partition (6132); the upper partition (6131) is provided with an upper partition opening (62) near the high-temperature water outlet (6112), and the lower partition (6132) is provided with a lower partition opening (63) near the low-temperature water inlet (6121); the water outlet of the first heat exchanger (2) is connected to the high-temperature water inlet (6111), the high-temperature water outlet (6112) is connected to the water inlet of the fifth heat exchanger (8) via a heating circulation water pump (7), the water outlet of the fifth heat exchanger (8) is connected to the low-temperature water inlet (6121), and the low-temperature water outlet (6122) is connected to the water inlet of the first heat exchanger (2) via a heating circulation water pump (5);A water supply pump (18) is provided between the softening water tank (17) and the third heat exchanger (12). ; 2. A coupled energy-saving system according to claim 1, characterized in that: The upper partition opening (62) and the lower partition opening (63) are both isosceles right triangle openings, and the waist length thereof is 400-600 mm.

3. A coupled energy-saving system according to claim 1, characterized in that: The fourth heat exchanger (10) and the remote liquid level meter (9) are both arranged in the high-temperature water tank (611).

4. A coupled energy-saving system according to claim 1, characterized in that: The upper side of the stratified water tank (6) is also provided with an overflow port.

5. The coupled energy-saving system according to claim 1, characterized in that: The flue gas from the natural gas boiler (11) is discharged from the chimney (13) above after heat exchange in the third heat exchanger (12).

6. A coupled energy-saving system according to claim 1, characterized in that: The drain device (14) recovers condensed water from the third heat exchanger (12) and delivers it to the softened water tank (17); the water in the softened water tank (17) is heated by the third heat exchanger (12) and then delivered to the natural gas boiler (11) for reuse.

7. The coupled energy-saving system according to claim 1, characterized in that: The internal combustion generator set (1) is a 400 kW internal combustion generator set, the first heat exchanger (2) is a 230 kW flue gas hot water heat exchanger, and the second heat exchanger (4) is a 240 kW plate heat exchanger; the third heat exchanger (12) is a flue gas hot water heat exchanger, the fourth heat exchanger (10) is a coil heat exchanger, and the fifth heat exchanger (8) is a heating heat exchanger.

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