Steam supply device of solar combined gas-fired boiler

Abstract

The invention relates to a steam supply device of a solar combined gas boiler. High-pressure unsaturated water is heated into high-pressure saturated water through solar energy, and then the high-pressure saturated water is continuously heated into saturated steam or superheated steam in the gas-fired boiler. Exhaust flue gas of the gas-fired boiler preheats inlet air of the gas-fired boiler through the air / flue gas heat exchanger. In this way, fuel of conventional natural gas can be saved, and about 20-40% of the conventional natural gas can be saved.

Description

Technical Field

[0001] The invention relates to the technical field of steam generating devices, and in particular to a steam supply device for a solar combined gas boiler. Background Art

[0002] Solar thermal utilization is a relatively mature way of utilizing renewable energy. my country has the world's largest solar thermal utilization market, conservatively estimated at about 45%. Solar thermal utilization is one of the most commercialized and widely used technologies in the field of renewable energy utilization. However, solar energy has two main disadvantages: one is the low energy flux density, which is only 200W / m if averaged over the whole year. 2 The second is instability, which is easily affected by natural conditions such as day and night, seasons, geographical latitude and altitude, as well as random factors such as sunny, cloudy, cloudy and rainy. In order to solve these two main shortcomings in solar thermal utilization, the present invention proposes a steam supply device combining solar energy and gas boiler to achieve seamless connection between solar energy and natural gas energy, and improve the economy and reliability of solar thermal utilization. Summary of the invention

[0003] The purpose of the present invention is to provide a stable, economical and reliable steam supply device by optimizing the combination of solar energy and gas boiler to address the two main shortcomings of solar energy.

[0004] The first technical solution provided by the present invention is a steam supply device for a solar-powered combined gas boiler, comprising a gas boiler, wherein a water inlet pipe of the gas boiler is connected to an oil-water heat exchanger, wherein the heat transfer medium of the oil-water heat exchanger is heat transfer oil, and the heat transfer oil obtains heat through a solar collector, and the heat transfer oil heated by the solar collector flows in two directions: one path flows into the oil-water heat exchanger; and the other path flows into a heat transfer oil tank;

[0005] The air introduced into the gas boiler is heat exchanged through the air / smoke heat exchanger and enters the hot air burner;

[0006] The exhaust gas of the gas boiler exchanges heat with the air introduced into the gas boiler.

[0007] Furthermore, the solar thermal collector is a medium to high temperature thermal collector.

[0008] Furthermore, the solar collector adopts a trough type or a linear Fresnel type.

[0009] Furthermore, the solar thermal collector heats the heat transfer oil and then inputs it into a heat transfer oil tank through a three-way and a stop valve, and the heat transfer oil tank outputs it to the oil-water heat exchanger through a heat transfer oil circulation pump.

[0010] Furthermore, the heat transfer oil after heat exchange in the oil-water heat exchanger is output to a cold heat transfer oil tank, and is input to the solar collector for heating through a cold heat transfer oil circulation pump.

[0011] Furthermore, the high-pressure saturated steam or superheated steam is delivered to downstream users for use.

[0012] Furthermore, the oil-water heat exchanger is connected to a water feed pump and a softened water treatment tank.

[0013] Furthermore, the air / flue gas heat exchanger is arranged inside the gas boiler.

[0014] The basic principle of the present invention is to heat high-pressure unsaturated water into high-pressure saturated water through solar energy, and then the high-pressure saturated water is further heated into saturated steam or superheated steam in the gas boiler. The exhaust flue gas of the gas boiler passes through the air / flue gas heat exchanger to preheat the inlet air of the gas boiler. This can save the fuel of conventional natural gas.

[0015] The second technical solution of the present invention is an energy-saving working method of a steam supply device of a solar combined gas boiler, comprising the following steps:

[0016] S1: The cold heat transfer oil is heated by the solar collector to a high temperature heat transfer oil of 200-250℃ and directly enters the oil-water heat exchanger for circulation; or / and

[0017] Open the thermal oil tank, set the thermal oil temperature to 230±20°C, and output it to the oil-water heat exchanger through the thermal oil circulation pump;

[0018] S2: The high-pressure unsaturated water input into the oil-water heat exchanger by the water feed pump has a pressure of 0.5±0.1Mpa and a temperature of 20±5℃. After heat exchange with the high-temperature heat transfer oil, the high-pressure unsaturated water is heated to high-pressure saturated water vapor at 180-200℃.

[0019] S3: The air introduced into the gas boiler is heated to 150±20℃ by the air / flue gas heat exchanger and then enters the hot air burner for combustion;

[0020] S4: Exhaust gas after combustion of the gas boiler is heat exchanged with air introduced into the gas boiler;

[0021] The mass ratio of the circulation amount directly entering the oil-water heat exchanger to the output amount of the thermal oil tank in the step S1 is 10-12:1.

[0022] Furthermore, when the solar energy is insufficient, the step S1 completely outputs the heat to the oil-water heat exchanger through the heat transfer oil circulation pump.

[0023] Beneficial effects are: Different from ordinary solar thermal utilization, the solar collector in this device is a medium-high temperature collector, which can heat the heat transfer oil to 200-250℃, while ordinary solar thermal utilization is usually a vacuum tube collector, which only heats water to 50-80℃. The device can realize the effective utilization of solar energy, improve the economy of solar thermal utilization, and achieve seamless connection with conventional energy, and improve the stability of solar energy utilization, as follows:

[0024] The steam supply device of the solar energy combined gas boiler of the present invention, the solar collector is a medium-high temperature heat collecting device, which can use the focused solar energy to heat the heat transfer oil to 200-250°C, and is used to heat the high-pressure unsaturated water to high-pressure saturated water above 150°C, thereby saving the amount of natural gas fuel, and can save up to 40% of conventional natural gas, fully realizing the combined utilization of solar energy and conventional energy.

[0025] The heat transfer oil tank of the present invention can store excess heat energy in the heat transfer oil tank when solar energy is sufficient, and the heat energy storage and direct entry into the oil-water heat exchanger achieve an optimal combination ratio, ensuring the thermal insulation of the stored heat transfer oil and full utilization of solar energy resources.

[0026] The air / smoke heat exchanger of the present invention can fully utilize the waste heat of the exhaust gas, thereby improving the economy of the steam supply device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a structural schematic diagram of a steam supply device for a solar energy combined gas boiler.

[0028] Figure 2 It is a schematic structural diagram of a second steam supply device of the present invention.

[0029] Figure numerals: 1—solar collector, 2—three-way joint, 3—stop valve; 4—hot thermal oil tank, 5—hot thermal oil circulation pump, 6—cold thermal oil tank, 7—cold thermal oil circulation pump, 8—oil-water heat exchanger; 9—feed water pump, 10—softened water treatment tank, 11—hot air burner, 12—gas boiler; 13—air / flue gas heat exchanger, 14—blower. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] As attached Figure 1 As shown, the steam supply device of the solar combined gas boiler of the present invention includes a solar collector 1, a heat transfer oil tank 4, an oil-water heat exchanger 8, a gas boiler 12, and an air / flue gas heat exchanger 13.

[0032] The present invention provides a steam supply device for a solar-powered combined gas boiler, comprising a gas boiler 12, wherein a water inlet pipe of the gas boiler 12 is connected to an oil-water heat exchanger 8, wherein the heat transfer medium of the oil-water heat exchanger 8 is heat transfer oil, and the heat transfer oil obtains heat through a solar collector 1, and the heat transfer oil heated by the solar collector 1 flows in two directions: one path flows into the oil-water heat exchanger 8; and the other path flows into a heat transfer oil tank 4;

[0033] The air introduced into the gas boiler 12 is heat exchanged through the air / smoke heat exchanger 13 and enters the hot air burner 11;

[0034] The exhaust gas of the gas boiler 12 exchanges heat with the air introduced into the gas boiler.

[0035] The solar thermal collector 1 is a medium to high temperature heat collecting device.

[0036] The solar thermal collector 1 is of trough type or linear Fresnel type.

[0037] The solar thermal collector 1 heats the heat transfer oil and then inputs the heated oil into the heat transfer oil tank 4 through the three-way joint 2 and the stop valve 3 . The heat transfer oil tank 4 outputs the heated oil to the oil-water heat exchanger 8 through the heat transfer oil circulation pump 5 .

[0038] The heat transfer oil after heat exchange in the oil-water heat exchanger 8 is output to the cold heat transfer oil tank 6, and is input to the solar collector 1 for heating through the cold heat transfer oil circulation pump 7.

[0039] The high-pressure saturated steam or superheated steam is delivered to downstream users for use.

[0040] The oil-water heat exchanger 8 is connected to a water supply pump 9 and a softened water treatment tank 10 .

[0041] As a preferred implementation method, as shown in the attached Figure 2 As shown, the air / smoke heat exchanger 13 is arranged inside the gas boiler 12, and the natural gas saving will be more obvious at this time, which can reach more than 55%.

[0042] An energy-saving working method of a steam supply device for a solar combined gas boiler comprises the following steps: S1: cold heat transfer oil is heated to 200-250°C high temperature heat transfer oil by a solar collector 1 and directly enters an oil-water heat exchanger 8 for circulation; or / and

[0043] Open the thermal oil tank 4, set the thermal oil temperature to 230±20°C, and output it to the oil-water heat exchanger 8 through the thermal oil circulation pump 5;

[0044] S2: The high-pressure unsaturated water inputted by the water pump 9 into the oil-water heat exchanger 8 has a pressure of 0.5±0.1Mpa and a temperature of 20±5°C. After heat exchange with the high-temperature heat transfer oil, the high-pressure unsaturated water is heated to high-pressure saturated water vapor at 180-200°C.

[0045] S3: The air introduced into the gas boiler 12 is heated to 150±20°C by the air / flue gas heat exchanger 13 and then enters the hot air burner 11 for combustion;

[0046] S4: Exhaust gas after combustion by the gas boiler 12 is heat exchanged with air introduced into the gas boiler 12;

[0047] The mass ratio of the circulation amount directly entering the oil-water heat exchanger 8 to the output amount of the heat transfer oil tank 4 in step S1 is 10-12:1.

[0048] Furthermore, in step S1 , when the solar energy is insufficient, the heat is completely output to the oil-water heat exchanger 8 through the heat transfer oil circulation pump 5 .

[0049] The solar collector 1 of the present invention preferably adopts a trough-type or linear Fresnel-type solar medium- and high-temperature heat collecting device, so the present invention can heat the heat transfer oil to 200-250°C, and then exchange heat with high-pressure unsaturated water in an oil-water heat exchanger to heat the high-pressure unsaturated water into high-pressure saturated water.

[0050] The gas boiler 12 of the present invention preferably replaces the economizer in the gas boiler 12 with an air / flue gas heat exchanger 13, in which the imported cold air exchanges heat with the exhaust flue gas of the gas boiler to increase the temperature of the cold air, and then further burns through the hot air burner 11 to heat it into high-temperature flue gas, and in the gas boiler 12, the high-temperature flue gas heats the high-pressure saturated water into high-pressure saturated steam. Therefore, the gas boiler 12 of the present invention needs to be equipped with a hot air burner 11, and the original economizer in the gas boiler is replaced with an air / flue gas heat exchanger 13, which is conducive to improving the economy of the steam supply device of the solar combined gas boiler.

[0051] Example 1

[0052] The present invention is based on the premise of improving the economy and reliability of solar thermal utilization. After being heated by the solar collector 1, the cold heat transfer oil forms high-temperature heat transfer oil (temperature is about 230°C), enters the oil-water heat exchanger 8, and exchanges heat with the high-pressure unsaturated water (about 0.5Mpa, 20°C) input into the oil-water heat exchanger 8 by the water supply pump 9. After the high-pressure unsaturated water is heated to form high-pressure saturated water (about 0.5Mpa, 180°C), it enters the gas boiler 12 and is reheated into high-pressure saturated steam, which is supplied to downstream users. Among them, the exhaust gas discharged from the gas boiler 12 enters the air / flue gas heat exchanger 13 to heat the inlet cold air.

[0053] The heat transfer oil is heated by the solar collector 1 (trough type or linear Fresnel type), and the heat transfer oil is heated to about 250°C. The high-temperature heat transfer oil is divided into two paths through the three-way joint 2, one path is directly input into the oil-water heat exchanger 8 to heat the high-pressure unsaturated water, and the other path enters the high-temperature heat transfer oil tank 4 for storage, so that when there is no solar energy, the heat transfer oil circulation pump 5 is used to input it into the oil-water heat exchanger 8 to continue heating the high-pressure unsaturated water. In Example 1, the mass ratio of the circulation amount directly input into the oil-water heat exchanger to the output amount of the heat transfer oil tank is 10:1, which saves the fuel amount of natural gas, achieving a saving of 40% of conventional natural gas.

[0054] After ordinary tap water is softened by the softening water treatment tank 10, it is pressurized into high-pressure (e.g., 0.5 MPa) unsaturated water by the water supply pump 9. The high-pressure unsaturated water is heated into high-pressure saturated water (e.g., 0.5 MPa, 180°C) in the oil-water heat exchanger 8. The high-pressure saturated water is further heated into saturated steam or superheated steam in the gas boiler 12 and supplied to downstream users. The preheated inlet air (about 150°C) is burned in the hot air burner 11 to produce high-temperature flue gas, which heats the high-pressure saturated water into saturated steam or superheated steam.

[0055] Example 2

[0056] In Example 2, except that the mass ratio of the circulation amount directly input into the oil-water heat exchanger to the output amount of the thermal oil tank is 12:1, the other aspects are the same as Example 1, and the amount of natural gas fuel is saved, achieving a saving of 35% of conventional natural gas.

[0057] Example 3

[0058] In Example 3, except that the mass ratio of the circulation amount directly input into the oil-water heat exchanger to the output amount of the thermal oil tank is 11:1, the other aspects are the same as Example 1, and the amount of natural gas fuel is saved, achieving a saving of 38.5% of conventional natural gas.

[0059] Example 4

[0060] The rest is the same as in Example 1. When the solar energy is insufficient, the heat is completely output to the oil-water heat exchanger 8 through the heat transfer oil circulation pump 5. The amount of natural gas fuel is saved, reaching 35% of conventional natural gas.

Claims

1. A steam supply device for a solar-powered combined gas boiler, comprising a gas boiler, characterized in that: The water inlet pipe of the gas boiler is connected to the oil-water heat exchanger, the heat transfer medium of the oil-water heat exchanger is thermal oil, the thermal oil obtains heat through the solar collector, and the thermal oil heated by the solar collector flows in two ways: one way flows into the oil-water heat exchanger; the other way flows into the thermal oil tank; The air introduced into the gas boiler is heat exchanged through the air / smoke heat exchanger and enters the hot air burner; The exhaust gas of the gas boiler exchanges heat with the air introduced into the gas boiler.

2. The steam supply device for a solar combined gas boiler according to claim 1 is characterized in that: The solar thermal collector is a medium- and high-temperature heat collecting device.

3. The steam supply device for a solar-fired combined gas boiler according to claim 1, characterized in that: The solar thermal collector adopts a trough type or a linear Fresnel type.

4. The steam supply device for a solar-fired combined gas boiler according to claim 1 is characterized in that: The solar collector heats the heat-conducting oil and then inputs the heated oil into a heat-conducting oil tank through a three-way connection and a stop valve. The heat-conducting oil tank then outputs the heated oil to the oil-water heat exchanger through a heat-conducting oil circulation pump.

5. The steam supply device for a solar-fired combined gas boiler according to claim 1, characterized in that: The heat transfer oil after heat exchange in the oil-water heat exchanger is output to a cold heat transfer oil tank, and is input to the solar collector for heating through a cold heat transfer oil circulation pump.

6. The steam supply device for a solar-fired combined gas boiler according to claim 1, characterized in that: The high-pressure saturated steam or superheated steam is delivered to downstream users for use.

7. The steam supply device for a solar-fired combined gas boiler according to claim 1, characterized in that: The oil-water heat exchanger is connected to the water feed pump and the softened water treatment tank.

8. The steam supply device for a solar-fired combined gas boiler according to claim 1, characterized in that: The air / smoke heat exchanger is arranged inside the gas boiler.

9. An energy-saving working method for a steam supply device of a solar combined gas boiler according to any one of claims 1 to 8, characterized in that: The steps include: S1: The cold heat transfer oil is heated by the solar collector to a high temperature heat transfer oil of 200-250℃ and directly input into the oil-water heat exchanger for circulation; or / and Open the thermal oil tank, set the thermal oil temperature to 230±20°C, and output it to the oil-water heat exchanger through the thermal oil circulation pump; S2: The high-pressure unsaturated water input into the oil-water heat exchanger by the water feed pump has a pressure of 0.5±0.1Mpa and a temperature of 20±5℃. After heat exchange with the high-temperature heat transfer oil, the high-pressure unsaturated water is heated to high-pressure saturated water vapor at 180-200℃. S3: The air introduced into the gas boiler is heated to 150±20℃ by the air / flue gas heat exchanger and then enters the hot air burner for combustion; S4: Exhaust gas after combustion of the gas boiler is heat exchanged with air introduced into the gas boiler; The mass ratio of the circulation amount directly input into the oil-water heat exchanger and the output amount of the heat transfer oil from the heat transfer oil tank in the step S1 is 10-12:

1.

10. The energy-saving working method of a solar-fired combined gas boiler according to claim 9, characterized in that: In step S1, when solar energy is insufficient, the heat is completely output to the oil-water heat exchanger through the heat transfer oil circulation pump.

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