A gas boiler machine-furnace deep coupling system and coupling method

Abstract

The present invention discloses a gas boiler machine-furnace deep coupling system and coupling method, the system comprises a first gas heater, a second gas heater, a first air preheater, a second air preheater, a high-pressure low-temperature economizer, a low-pressure low-temperature economizer, a low-temperature economizer, a water supply tank, a plurality of low-pressure heaters and a plurality of high-pressure heaters, the first gas heater is connected to the second gas heater and then connected to the boiler furnace, the first air preheater is connected to the second air preheater and then connected to the boiler furnace, one end of the high-pressure low-temperature economizer is connected to condensate, and the other end is connected to the boiler economizer, the low-pressure low-temperature economizer is connected to the condensate pipeline, and a plurality of low-pressure heaters and a plurality of high-pressure heaters are arranged on the condensate pipeline, and the low-temperature air or condensate is heated by switching the use state of the low-temperature economizer. In the present invention, the energy-saving potential of supercritical gas boilers can be fully tapped, the thermal efficiency of the whole plant of the unit can be effectively improved, and the energy-saving and emission-reduction benefits of the unit can be improved by improving the thermal efficiency of the whole plant of the unit.

Description

Technical Field

[0001] The invention belongs to the technical field of boiler energy conservation and emission reduction, and in particular relates to a gas boiler machine-furnace deep coupling system and a coupling method. Background Art

[0002] At present, the gas boilers in steel plants generally reduce the exhaust gas temperature by installing a first-level gas heater in the boiler tail flue at the outlet of the air preheater. This technology can reduce the boiler flue gas temperature by 20 to 30°C. However, even for blast furnace gas boilers equipped with gas heaters, the exhaust gas temperature is still as high as 130 to 150°C. In other words, although the existing technology has recycled the waste heat of flue gas to a certain extent, the utilization is still not sufficient, and there is still a lot of room for the exhaust gas temperature to decrease, which has caused energy waste to a certain extent. In addition, supercritical boilers are currently put into operation for gas boilers. Therefore, deep coupling of blast furnace gas boilers and boilers to improve the thermal efficiency of the entire plant is a major goal of current supercritical gas power plants. Summary of the invention

[0003] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a gas boiler machine-furnace deep coupling system and coupling method.

[0004] In order to achieve the above purpose and the above technical effect, the technical solution adopted by the present invention is:

[0005] A gas boiler machine-furnace deep coupling system comprises a first gas heater, a second gas heater, a first air preheater, a second air preheater, a high-pressure and low-temperature economizer, a low-pressure and low-temperature economizer, a low-temperature economizer, a water supply tank, a plurality of low-pressure heaters and a plurality of high-pressure heaters. The first gas heater, the second gas heater, the second air preheater, the high-pressure and low-temperature economizer, the low-pressure and low-temperature economizer are arranged in the boiler flue. The first gas heater is connected to the second gas heater and then to the boiler furnace. The first air preheater is connected to the second air preheater and then to the boiler furnace. One end of the high-pressure and low-temperature economizer is connected to condensate and the other end is connected to the boiler economizer. The low-pressure and low-temperature economizer is connected to a condensate pipeline. A plurality of low-pressure heaters and a plurality of high-temperature heaters are arranged on the condensate pipeline. The heating of low-temperature air or condensate is achieved by switching the use state of the low-temperature economizer.

[0006] Furthermore, the flue at the boiler economizer outlet is divided into three, including a first flue, a second flue, and a third flue. The first flue and the second flue are separated by a partition wall arranged in the boiler. The first flue is equipped with a second air preheater, the second flue is equipped with a high-pressure and low-temperature economizer and a low-pressure and low-temperature economizer, and the third flue is equipped with a second gas heater.

[0007] Furthermore, the inlet of the high-pressure and low-temperature economizer is connected to the outlet of the feed water pump on the condensate pipeline, the inlet of the feed water pump is connected to the deaerator and several low-temperature heaters, and the outlet of the high-pressure and low-temperature economizer is connected to the inlet of the boiler economizer.

[0008] Furthermore, the inlet of the feed water pump is connected to the deaerator, the first low-temperature heater and the second low-temperature heater in sequence.

[0009] Furthermore, the inlet of the low-pressure and low-temperature economizer is used to input external condensate, and the outlet of the low-pressure and low-temperature economizer is connected between the low-pressure heater outlet and the inlet of the deaerator on the condensate pipeline, and the flow rate of condensate entering the low-pressure and low-temperature economizer is controllable.

[0010] Furthermore, the condensate water pipeline is provided with a first low-temperature heater and a second low-temperature heater that are connected to each other, the outlet of the low-temperature economizer is connected to the first low-temperature heater and the second low-temperature heater in one way, and is connected to the first air preheater in another way, the inlet of the low-temperature economizer is connected to a make-up water tank in one way, is connected to the first air preheater in another way, and is still connected to the condensate water pipeline in another way.

[0011] Furthermore, the outlet of the low-temperature economizer is connected to the inlet of the first low-temperature heater and the outlet of the second low-temperature heater through a first valve, and is connected to the inlet of the first air preheater through a third valve. The inlet of the low-temperature economizer is connected to the make-up water tank through a fifth valve and a make-up water pump, and is connected to the outlet of the first air preheater through a fourth valve and a circulating water pump, and is connected to the condensate pipeline through a second valve.

[0012] A coupling method for a gas boiler deep coupling system comprises the following steps:

[0013] The low-temperature gas is heated by the first gas heater to become medium-temperature gas, and then heated by the second gas heater to become high-temperature gas, and then enters the boiler furnace for combustion;

[0014] The low-temperature air becomes medium-temperature air after passing through the first air preheater, and then becomes high-temperature air after passing through the second air preheater, and then enters the boiler furnace to participate in combustion;

[0015] The external condensate is sent to the second low-pressure heater and the low-pressure low-temperature economizer according to actual needs. The flow rate of condensate entering the low-pressure low-temperature economizer is controllable, which can adjust the water temperature at the outlet of the low-pressure low-temperature economizer and control the flue gas temperature at the outlet of the low-pressure low-temperature economizer, which helps to improve the thermal efficiency of the whole plant;

[0016] Switch the use status of the low-temperature economizer according to actual needs to heat the low-temperature air or condensate.

[0017] Furthermore, when the condensate enters the feed water pump through the second low-pressure heater, the first low-pressure heater and the deaerator in sequence, part of the feed water at the outlet of the feed water pump enters the high-pressure and low-temperature economizer for heating, and the other part continues to be transported to the high-pressure heater for heating. The water heated by the high-pressure and low-temperature economizer is mixed with the high-temperature feed water at the outlet of the high-pressure heater and enters the inlet of the boiler economizer together, and enters the superheater after heating. The high-pressure heater is not limited to one; when the condensate enters the low-pressure and low-temperature economizer and is heated, it returns to between the outlet of the first low-pressure heater and the inlet of the deaerator, and is then transported to the deaerator, and then enters the feed water pump, and the above operation is repeated until it enters the superheater.

[0018] Furthermore, when the third valve, the fourth valve, and the fifth valve are closed, and the first valve and the second valve are opened, the condensate at the inlet of the second low-temperature heater enters the low-temperature economizer through the second valve to absorb heat, and then returns to between the inlet of the first low-temperature heater and the outlet of the second low-temperature heater through the first valve; when the first valve and the second valve are closed, the third valve and the fourth valve are opened, and the circulating water pump is started to heat the low-temperature air to medium-temperature air;

[0019] If there is water shortage on the working medium side of the low-temperature economizer or the unit is started, the low-temperature economizer is replenished with water through the water replenishment tank and water replenishment pump.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention discloses a gas boiler machine-furnace deep coupling system and a coupling method. The system comprises a first gas heater, a second gas heater, a first air preheater, a second air preheater, a high-pressure low-temperature economizer, a low-pressure low-temperature economizer, a low-temperature economizer, a water supply tank, a plurality of low-pressure heaters and a plurality of high-pressure heaters. The first gas heater, the second gas heater, the second air preheater, the high-pressure low-temperature economizer, the low-pressure low-temperature economizer and the low-temperature economizer are arranged in the boiler flue. The first gas heater is connected to the second gas heater and then to the boiler furnace. The first air preheater is connected to the second air preheater and then to the boiler furnace. One end of the high-pressure low-temperature economizer is connected to condensate and the other end is connected to the boiler economizer. The low-pressure low-temperature economizer is connected to a condensate pipeline. A plurality of low-pressure heaters and a plurality of high-temperature heaters are arranged on the condensate pipeline. The heating of low-temperature air or condensate is achieved by switching the use state of the low-temperature economizer. In the present invention, the energy-saving potential of the supercritical gas boiler can be fully tapped, the thermal efficiency of the whole plant of the unit can be effectively improved, and the energy-saving and emission reduction benefits of the unit can be improved by improving the thermal efficiency of the whole plant of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a gas boiler machine-furnace deep coupling system of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0024] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0025] like Figure 1 As shown, a gas boiler machine-furnace deep coupling system comprises: a boiler economizer 1, a first gas heater 2, a second gas heater 3, a first air preheater 4, a second air preheater 5, a high-pressure low-temperature economizer 6, a low-pressure low-temperature economizer 7, a low-temperature economizer 8, a first low-temperature heater 9, a second low-temperature heater 10, a deaerator 11, a feed water pump 12, a high-temperature heater 13, a make-up water tank 14, a make-up water pump 15, a circulating water pump 16, a boiler furnace 17, a superheater 18 and a partition wall 24, the first gas heater 2, the second gas heater 3 , the second air preheater 5, the high-pressure and low-temperature economizer 6, the low-pressure and low-temperature economizer 7, and the low-pressure and low-temperature economizer 8 are arranged in the boiler flue, one end of the high-pressure and low-temperature economizer 6 is connected to the outlet pipeline of the feed water pump 12, and the other end is connected to the boiler economizer 1, the low-pressure and low-temperature economizer 7 is connected to the condensate pipeline, and the flow rate of the condensate in the condensate pipeline entering the low-pressure and low-temperature economizer 7 is controllable. Several low-pressure heaters and several high-pressure heaters are arranged on the condensate pipeline, and the heating of low-temperature air or condensate is achieved by switching the use status of the low-pressure and low-temperature economizer 8.

[0026] As a specific implementation, the flue at the outlet of the boiler economizer 1 is divided into three, including a first flue, a second flue, and a third flue. The first flue and the second flue are separated by a partition wall 24 arranged in the boiler. Figure 1 The thick arrow in the figure indicates the direction of flue gas flow. The first flue at the outlet of the boiler economizer 1 is equipped with a second air preheater 5. The first air preheater 4 is connected to the second air preheater 5 and then connected to the boiler furnace 17. The second flue is equipped with a high-pressure and low-temperature economizer 6 and a low-pressure and low-temperature economizer 7. The third flue is equipped with a second gas heater 3. The gas outlet of the first gas heater 2 is connected to the gas inlet of the second gas heater 3 and then connected to the boiler furnace 17.

[0027] The inlet of the high-pressure and low-temperature economizer 6 is connected to the outlet of the feed water pump 12 on the condensate pipeline, the inlet of the feed water pump 12 is connected to the deaerator 11 and several low-temperature heaters, the outlet of the high-pressure and low-temperature economizer 6 is connected to the inlet of the boiler economizer 1, the inlet of the low-pressure and low-temperature economizer 7 is used to input external condensate, and the outlet of the low-pressure and low-temperature economizer 7 is connected between the low-temperature heater outlet on the condensate pipeline and the inlet of the deaerator 11.

[0028] The outlet of the low-temperature economizer 8 is connected to the low-temperature heater in one way and to the inlet of the first air preheater 4 in another way. The inlet of the low-temperature economizer 8 is connected to the make-up water tank 14 through the make-up water pump 15 in one way and to the outlet of the first air preheater 4 through the circulating water pump 16 in another way, and is connected to the condensate pipeline in another way.

[0029] Example 1

[0030] like Figure 1 As shown, a gas boiler machine-furnace deep coupling system includes: a boiler economizer 1, a first gas heater 2, a second gas heater 3, a first air preheater 4, a second air preheater 5, a high-pressure and low-temperature economizer 6, a low-pressure and low-temperature economizer 7, a low-temperature economizer 8, a first low-temperature heater 9, a second low-temperature heater 10, a deaerator 11, a feed water pump 12, a high-temperature heater 13, a make-up water tank 14, a make-up water pump 15, a circulating water pump 16, a boiler furnace 17, a superheater 18, a first valve 19, a second valve 20, a third valve 21, a fourth valve 22, a fifth valve 23 and a partition wall 24.

[0031] The flue at the outlet of the boiler economizer 1 is divided into three parts, including a first flue, a second flue, and a third flue. The first flue and the second flue are separated by a partition wall 24 arranged in the boiler. Figure 1 The thick arrows in the figure indicate the direction of flue gas flow. The first flue at the outlet of the boiler economizer 1 is equipped with a second air preheater 5, the second flue is equipped with a high-pressure and low-temperature economizer 6 and a low-pressure and low-temperature economizer 7, and the third flue is equipped with a second gas heater 3.

[0032] The gas outlet of the first gas heater 2 is connected to the gas inlet of the second gas heater 3 and then connected to the boiler furnace 17 .

[0033] The first air preheater 4 is connected to the second air preheater 5 and then connected to the boiler furnace 17 .

[0034] The inlet of the high-pressure and low-temperature economizer 6 is connected to the outlet of the feed water pump 12, the outlet of the high-pressure and low-temperature economizer 6 is connected to the inlet of the boiler economizer 1, the inlet of the low-pressure and low-temperature economizer 7 is used to input external condensate, and the outlet of the low-pressure and low-temperature economizer 7 is connected between the outlet of the first low-temperature heater 9 and the inlet of the deaerator 11.

[0035] The outlet of the second low-temperature heater 10 can be directly connected to the first low-temperature heater 9, the outlet of the low-temperature economizer 8 can be connected between the inlet of the first low-temperature heater 9 and the outlet of the second low-temperature heater 10 through the opened first valve 19, the outlet of the low-temperature economizer 8 can also be connected to the inlet of the first air preheater 4 through the opened third valve 21, the inlet of the low-temperature economizer 8 can be connected to the make-up water tank 14 through the fifth valve 23 and the make-up water pump 15, the inlet of the low-temperature economizer 8 can also be connected to the outlet of the first air preheater 4 through the fourth valve 22 and the circulating water pump 16, and the inlet of the low-temperature economizer 8 can also directly input external condensate through the second valve 20.

[0036] The coupling method of the gas boiler deep coupling system of the present invention comprises the following steps:

[0037] The low-temperature coal gas is heated by the first coal gas heater 2 to become medium-temperature coal gas, and then heated by the second coal gas heater 3 to become high-temperature coal gas, and then enters the boiler furnace 17 through the boiler burner (not shown in the figure) for combustion;

[0038] The low-temperature air passes through the first air preheater 4 to become medium-temperature air, and then passes through the second air preheater 5 to become high-temperature air, and then enters the boiler furnace 17 to participate in combustion;

[0039] The external condensate is sent to the second low-pressure heater 10 and the low-pressure low-temperature economizer 7 according to actual needs. The low-pressure low-temperature economizer 7 can control the opening of its valve to be fully open or partially open according to actual needs, so that the flow rate of the condensate entering the low-pressure low-temperature economizer 7 can be controlled, which is convenient for adjusting the water temperature at the outlet of the low-pressure low-temperature economizer 7 and controlling the flue gas temperature at the outlet of the low-pressure low-temperature economizer 7, which helps to improve the thermal efficiency of the whole plant. When the condensate enters the feed water pump 12 via the second low-pressure heater 10, the first low-pressure heater 9 and the deaerator 11 in sequence, part of the feed water at the outlet of the feed water pump 12 enters the high-pressure and low-temperature economizer 6 for heating, and the other part continues to be transported to the high-pressure heater 13 for heating. The water heated by the high-pressure and low-temperature economizer 6 is mixed with the high-temperature feed water at the outlet of the high-pressure heater 13 and enters the inlet of the boiler economizer 1 together, and enters the superheater 18 after heating. The high-pressure heater 13 is not limited to one; when the condensate enters the low-pressure and low-temperature economizer 7 for heating, it returns to between the outlet of the first low-pressure heater 9 and the inlet of the deaerator 11, and is then transported to the deaerator 11, and then enters the feed water pump 12, and the above operation is repeated until it enters the superheater 18; the present invention can set multiple low-pressure heaters according to actual needs;

[0040] The use state of the low-temperature economizer 8 can be switched according to actual needs to heat low-temperature air or condensate; when the third valve 21, the fourth valve 22, and the fifth valve 23 are closed, and the first valve 19 and the second valve 20 are opened, the condensate at the inlet of the second low-temperature heat pump 10 enters the low-temperature economizer 8 through the second valve 20 to absorb heat, and then returns to between the inlet of the first low-temperature heat pump 9 and the outlet of the second low-temperature heat pump 10 through the first valve 19; when the first valve 19 and the second valve 20 are closed, the third valve 21 and the fourth valve 22 are opened, and the circulating water pump 16 is started to heat the low-temperature air to medium-temperature air;

[0041] If there is a water shortage on the working medium side of the low-temperature economizer 8 or the unit is started, the low-temperature economizer 8 can be replenished with water through the water replenishment tank 14 and the water replenishment pump 15.

[0042] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0043] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A gas boiler machine-furnace deep coupling system, characterized in that: It includes a first gas heater, a second gas heater, a first air preheater, a second air preheater, a high-pressure and low-temperature economizer, a low-pressure and low-temperature economizer, a low-pressure and low-temperature economizer, a water supply tank, a plurality of low-pressure heaters and a plurality of high-pressure heaters. The first gas heater, the second gas heater, the second air preheater, the high-pressure and low-temperature economizer, the low-pressure and low-temperature economizer are arranged in the flue of the boiler. The first gas heater is connected to the second gas heater and then connected to the boiler furnace. The first air preheater is connected to the second air preheater and then connected to the boiler furnace. One end of the high-pressure and low-temperature economizer is connected to condensate and the other end is connected to the boiler economizer. The low-pressure and low-temperature economizer is connected to the condensate pipeline. The condensate pipeline is provided with a plurality of low-pressure heaters and a plurality of high-pressure heaters. The heating of low-temperature air or condensate is achieved by switching the use state of the low-pressure and low-temperature economizers. The flue at the boiler economizer outlet is divided into three parts, including a first flue, a second flue, and a third flue. The first flue and the second flue are separated by a partition wall arranged in the boiler. The first flue is equipped with a second air preheater, the second flue is equipped with a high-pressure and low-temperature economizer and a low-pressure and low-temperature economizer, and the third flue is equipped with a second gas heater; The inlet of the high-pressure and low-temperature economizer is connected to the outlet of the feed water pump on the condensate pipeline, the inlet of the feed water pump is connected to the deaerator and several low-temperature heaters, and the outlet of the high-pressure and low-temperature economizer is connected to the inlet of the boiler economizer; The inlet of the water supply pump is connected to the deaerator, the first low-temperature heater and the second low-temperature heater in sequence; The inlet of the low-pressure and low-temperature economizer is used to input external condensate, and the outlet of the low-pressure and low-temperature economizer is connected between the outlet of the low-pressure heater on the condensate pipeline and the inlet of the deaerator, and the flow rate of the condensate entering the low-pressure and low-temperature economizer is controllable; The condensate water pipeline is provided with a first low-temperature heater and a second low-temperature heater connected to each other, the outlet of the low-temperature economizer is connected to between the first low-temperature heater and the second low-temperature heater in one way, and connected to the first air preheater in another way, the inlet of the low-temperature economizer is connected to a water supply tank in one way, connected to the first air preheater in another way, and connected to the condensate water pipeline in another way; The outlet of the low-temperature economizer is connected to the inlet of the first low-temperature heater and the outlet of the second low-temperature heater through the first valve, and is connected to the inlet of the first air preheater through the third valve. The inlet of the low-temperature economizer is connected to the make-up water tank through the fifth valve and the make-up water pump, and is connected to the outlet of the first air preheater through the fourth valve and the circulating water pump, and is connected to the condensate pipeline through the second valve.

2. The coupling method of a gas boiler deep coupling system according to claim 1 is characterized in that: The following steps are involved: The low-temperature gas is heated by the first gas heater to become medium-temperature gas, and then heated by the second gas heater to become high-temperature gas, and then enters the boiler furnace for combustion; The low-temperature air becomes medium-temperature air after passing through the first air preheater, and then becomes high-temperature air after passing through the second air preheater, and then enters the boiler furnace to participate in combustion; The external condensate is sent to the second low-pressure heater and the low-pressure and low-temperature economizer according to actual demand. The flow rate of condensate entering the low-pressure and low-temperature economizer is controllable. Switch the use status of the low-temperature economizer according to actual needs to heat the low-temperature air or condensate.

3. The coupling method of a gas boiler deep coupling system according to claim 2 is characterized in that: When the condensate enters the feed water pump through the second low-pressure heater, the first low-pressure heater and the deaerator in sequence, part of the feed water at the outlet of the feed water pump enters the high-pressure and low-temperature economizer for heating, and the other part continues to be transported to the high-pressure heater for heating. The water heated by the high-pressure and low-temperature economizer is mixed with the high-temperature feed water at the outlet of the high-pressure heater and enters the inlet of the boiler economizer together, and enters the superheater after heating. The high-pressure heater is not limited to one; when the condensate enters the low-pressure and low-temperature economizer and is heated, it returns to between the outlet of the first low-pressure heater and the inlet of the deaerator, and is then transported to the deaerator, and then enters the feed water pump, and the above operation is repeated until it enters the superheater.

4. The coupling method of a gas boiler deep coupling system according to claim 2, characterized in that: When the third valve, the fourth valve and the fifth valve are closed, and the first valve and the second valve are opened, the condensate at the inlet of the second low-temperature heater enters the low-temperature economizer through the second valve to absorb heat, and then returns to the inlet of the first low-temperature heater and the outlet of the second low-temperature heater through the first valve; when the first valve and the second valve are closed, the third valve and the fourth valve are opened, the circulating water pump is started to heat the low-temperature air to high-temperature air; If there is water shortage on the working medium side of the low-temperature economizer or the unit is started, the low-temperature economizer is replenished with water through the water replenishment tank and water replenishment pump.

Images