Combined steam generating device with preheating water tank and method for producing steam

Abstract

The present invention relates to a combined steam generating device with a preheating water tank, comprising a softening water processor, a normal pressure heating water system and a steam production system which are sequentially connected in series through pipelines; the steam production system comprises a steam boiler, a variable frequency water supply pump, a check valve and a preheating water inlet pipeline; the normal pressure heating water system comprises a preheating electromagnetic boiler, a preheating water tank, a circulating water pump, an electromagnetic valve and a cold water pipeline; the outlet of the softening water processor is connected to the upper part of the preheating water tank through the cold water pipeline; during operation, incoming water is input into the preheating water tank; at night, the preheating electromagnetic boiler is turned on, and the circulating water pump circulates the water in the preheating water tank into the preheating electromagnetic boiler for heating; during daytime, the burner of the gas steam boiler is turned on, and the flue gas further heats the hot water in the waste heat recovery device, and the hot water enters the gas steam boiler to generate steam.

Description

Technical Field

[0001] The present invention relates to the technical field of steam supply, in particular to a steam generator, and more particularly to a combined steam generating device for preheating water by using night off-peak electricity and daytime peak electricity. Background Art

[0002] Steam is needed in many fields such as hotels, laboratories, and industrial manufacturing. Usually, steam comes from the municipal centralized steam supply system, regional steam supply system, or distributed steam supply system. The steam generator is the core component of the steam supply system. Steam generators mainly include power plant exhaust steam devices, coal-fired boilers, gas-fired boilers, oil-fired boilers, resistance boilers, electromagnetic boilers, and biomass boilers. In essence, a steam generator is an energy conversion device. The development of steam generator technology pursues the degree of environmental impact, energy conversion efficiency, and economy.

[0003] The Chinese patent (publication number: CN 102384577 B ) provides a three-phase industrial frequency electromagnetic dual induction heating device and heating method for liquid. The positive effect is that the magnetic conductive frame can conduct both magnetism and flow, which increases the flow rate of all circulating liquids when passing through the channel between the short-circuit and eddy current heating devices, and the heat exchange is more complete, which is beneficial to the service life of the short-circuit heating device; the magnetic conductive frame limits the radiation of leakage magnetic flux, ensuring safe operation; the magnetic conductive frame converts the reactive short-circuit leakage magnetic energy into heat energy, saving energy and money.

[0004] The Chinese patent (publication number: CN 107613596 A) relates to a single-phase power frequency electromagnetic induction short-circuit heating device for liquid, which is entirely composed of silicon steel sheets stacked to form a CI-shaped iron core in a closed single-phase magnetic circuit; each of the two core pillars of the iron core surrounds a single-phase primary winding, and the two windings are connected in series or in parallel in the same magnetic circuit direction; the iron core and the winding are all encapsulated in a metal shell, and the space in the metal shell is filled with insulating fillers; the metal shell is arranged along the closed magnetic circuit of the single-phase iron core to form a short-circuit secondary side surrounding the iron core and the two windings to become the main heating element; the metal shell is composed of a shell, a rectangular tube, and a terminal block; the terminal block is welded on the upper side of one side of the shell, and the lead wire of the single-phase primary winding is led out from the terminal block; the left and right sides of the rectangular tube and the shell respectively form two short-circuit metal rings surrounding the two windings, and the upper and lower sides respectively form two short-circuit metal rings surrounding the upper and lower yoke irons of the iron core. The heating device improves the power factor, making cosΦ≥ 0.997.

[0005] Current steam generating devices generally soften incoming water first; then preheat the softened water to a certain temperature; and then heat the preheated water to a boiling point, causing a phase change to generate water vapor.

[0006] The Chinese patent (Announcement No.: CN 207555566U) provides a valley electricity energy storage electric heating steam generator, including a valley electricity heat storage container and a steam generator, which are connected and a water pump is arranged between the two, and a check valve is arranged between the steam generator and the water pump. The valley electricity heat storage container at normal pressure and the pressurized steam generator are respectively equipped with electric heating pipes. The water in the heat storage container is heated to the required temperature by using the cheap valley electricity at night, and is heated to generate steam by the steam generator during the day, thereby reducing the electricity usage fee and production cost to the same level as other fuels such as coal, natural gas and oil, saving expenses for enterprises.

[0007] A Chinese patent (publication number: CN 108506914 A) discloses an electric heat storage preheating steam generator, comprising a heat storage open water tank, the water outlet of the heat storage open water tank is connected to the suction port of a booster pump, the outlet of the booster pump is connected to the water inlet of a heating pressure water tank, a breathing tube is provided on the top of the heat storage open water tank, a liquid level control valve is provided on the water inlet of the heat storage open water tank, a heating device and a second temperature sensor are provided inside the heat storage open water tank, the heating device is electrically connected to the second temperature sensor, an electric heater 1, a liquid level sensor, a pressure sensor and a temperature sensor 1 are provided inside the heating pressure water tank, the liquid level sensor is electrically connected to the booster pump, the pressure sensor and the temperature sensor 1 are electrically connected to the electric heater 1 respectively, a safety valve is provided on the top of the heating pressure water tank, the safety valve is electrically connected to the pressure sensor, and a steam outlet is provided on the top of the heating pressure water tank.

[0008] The heat sources of the above two steam generators are electric heating tubes, that is, heating is performed by a resistance heater, and the electric heating tubes are directly inserted into the water tank, which has poor safety, low electric heat conversion efficiency and poor economy.

[0009] The Chinese patent (Announcement No.: CN 108591990A) discloses a combined energy steam generator, including a combustion furnace and an electric heating furnace. The bottom of the electric heating furnace is provided with a sewage pipe, the top of the electric heating furnace is provided with a pressure instrument and a steam pipe, the bottom of the combustion furnace is provided with a burner, the interior of the combustion furnace is provided with a spiral pipe, the top of the combustion furnace is provided with a chimney, one end of the spiral pipe extends out of the combustion furnace and extends into the electric heating furnace to be a circulating water distribution pipe of the electric heating furnace, the bottom of the electric heating furnace is provided with a circulating water pipe, the circulating water pipe is provided with a circulating water pump, the circulating water pipe is connected to the other end of the spiral pipe, and an electric heater is provided in the electric heating furnace. It adopts the complementary application of two clean energy sources, electric energy and natural gas. Natural gas energy is used during the day, and electric heating is used for thermal operation at night using off-peak electricity.

[0010] This patent is a combination of a gas boiler and an electric boiler with matching pipes, water pumps, etc. However, these two boilers are only equipped with one steam pipe (outlet), which is located on the top of the electric boiler; in this way, the steam generated by the gas boiler must be output through the electric boiler, that is, one boiler is in operation, bearing the heat dissipation loss of the furnace body of two boilers, which is undoubtedly inefficient and has high operating costs. In addition, the above two boilers are equipped with a water supply channel, which is transported to the electric boiler through the condenser in the exhaust pipe of the gas boiler. The condenser is a vulnerable part. It is affected by the high-temperature corrosive flue gas in the exhaust pipe. Once damaged, the water supply is interrupted, and the two boilers are forced to stop at the same time, which has poor reliability; furthermore, its circulating feed and return water spiral tube heating system, the gas boiler gradually changes from the low-temperature feed water during the initial operation to the saturated high-temperature feed water. Because the spiral tube is heated unevenly in the furnace, whether steam explosion will occur in the high-heated spiral tube part is worth considering. Summary of the invention

[0011] The purpose of the present invention is to overcome the defects of the prior art and provide a combined steam generating device with a preheating water tank and a method for generating steam thereof, which utilizes electric energy, especially cheap valley electricity, to preheat external soft water and has good safety performance and high electric-thermal conversion efficiency, so that cheap valley electricity can be efficiently utilized, the operating efficiency of the boiler is improved, the energy consumption is reduced, and the cost is lowered.

[0012] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a combined steam generating device with a preheating water tank, from the water inlet to the steam outlet, including a soft water processor, a normal pressure heating water system and a steam production system connected in series through pipelines; the steam production system includes a steam boiler, a variable frequency water supply pump, a check valve and a preheating water inlet pipeline; the normal pressure heating water system includes a preheating electromagnetic boiler, a preheating water tank, a circulating water pump, an electromagnetic valve, and a cold water pipeline.

[0013] The outlet of the soft water processor is connected to the upper part of the preheating water tank through a cold water pipe, and a solenoid valve is provided on the cold water pipe.

[0014] A manhole and a float valve are arranged on the upper part of the preheating water tank, and the float valve is electrically connected to the solenoid valve.

[0015] The lower side of the preheating water tank is connected to the water inlet of the preheating electromagnetic boiler at the lower part of the preheating electromagnetic boiler through a circulating water inlet pipeline, and a circulating water pump is arranged on the circulating water inlet pipeline.

[0016] The water outlet of the preheating electromagnetic boiler at the top of the preheating electromagnetic boiler is connected to the upper part of the preheating water tank through a circulating water outlet pipeline.

[0017] The lower part of the preheating water tank away from the preheating electromagnetic boiler enters the preheating water inlet at the upper part of the steam boiler through the preheating water inlet pipe, and the preheating water inlet pipe is sequentially connected with a thermometer, a variable frequency water pump and a check valve.

[0018] The steam boiler is provided with a water level meter, a steam outlet and a safety valve, and the water level meter is electrically connected to the variable frequency water feed pump.

[0019] Furthermore, the steam boiler is a gas-fired steam boiler, comprising a burner and a waste heat recovery device; the burner is arranged at the bottom of the gas-fired steam boiler, and the waste heat recovery device is arranged in the flue of the gas-fired steam boiler;

[0020] The preheating water inlet pipe enters the waste heat recovery device from the water inlet of the waste heat recovery device, then winds through the waste heat recovery device, passes through the water outlet of the waste heat recovery device, and enters the gas steam boiler from the preheated water inlet on the upper part of the gas steam boiler;

[0021] A high-temperature water thermometer, a temperature sensor and a high-temperature water check valve are provided in the preheating water inlet pipe from the water outlet of the waste heat recovery device to the preheating water inlet, and the temperature sensor is electrically connected to the electric control box of the preheating electromagnetic boiler.

[0022] The water inlet of the waste heat recovery device is located at the end of the flue, and the water outlet of the waste heat recovery device is located at the starting end of the flue.

[0023] Furthermore, the preheating electromagnetic boiler and the electric control box of the preheating electromagnetic boiler are installed on the same base; the preheating electromagnetic boiler is a three-phase industrial frequency induction electromagnetic boiler, or a single-phase industrial frequency induction electromagnetic boiler.

[0024] The preheating water tank is further insulated on six sides.

[0025] Furthermore, the steam boiler is an electric boiler; the electric boiler is a resistance boiler or an electromagnetic boiler.

[0026] A method for producing steam using a combined steam generating device with a preheating water tank comprises the following steps:

[0027] Step 1: Input the softened water into the preheating water tank through the cold water pipe. The float valve and the solenoid valve work together to keep the preheating water tank at a reasonable water level.

[0028] Step 2: Use off-peak electricity to start the preheating electromagnetic boiler at night, and the circulating water pump circulates the water in the preheating water tank into the preheating electromagnetic boiler for heating.

[0029] Step 3: Turn on the burner of the gas steam boiler during the day. The flue gas in the flue will further heat the hot water in the waste heat recovery device, and the hot water will enter the gas steam boiler to generate steam.

[0030] The present invention has the following positive effects: first, the preheating electromagnetic boiler utilizes electric energy, especially valley electricity, to heat the normal temperature soft water in the preheating water tank to the set temperature through the circulating water pump and store it for use throughout the day, which correspondingly reduces the gas consumption of the gas steam boiler in the process of heating the feed water; second, the variable frequency feed water pump conveys the preheated soft water through the waste heat recovery device for reheating, and the boiler feed water direction is opposite to its exhaust direction. Through the convection heat transfer principle, the waste heat is recovered from the high-temperature flue gas discharged by the boiler, so that the water temperature of the boiler feed water is increased for the gas steam boiler to produce steam, and the preheating electromagnetic boiler and the gas steam boiler are combined in series to heat the feed water, thereby increasing the feed water temperature of the gas steam boiler, and stably increasing the temperature of the boiler combustion chamber, with high combustion efficiency and low gas consumption; especially at the end of the waste heat recovery device, close to the high-temperature flue gas outlet, the water temperature is heated to the boiling point, causing Phase change absorbs heat, and the flue gas temperature drops significantly, and the waste heat recovery efficiency is higher; third, the preheating electromagnetic boiler uses a three-phase industrial frequency induction electromagnetic boiler or a single-phase industrial frequency induction electromagnetic boiler according to the amount of steam produced. The industrial frequency induction electromagnetic boiler uses the trinity heating principle of "short-circuit heating, hysteresis heating, and eddy current heating". Because hysteresis and eddy current are generated by short-circuit leakage magnetic field, and leakage magnetic field is reactive, the boiler converts almost all active and reactive electrical energy into thermal energy, so it is more efficient; fourth, the variable frequency feed water pump automatically supplies water according to the steam production and water consumption of the gas steam boiler, so that the water level in the gas steam boiler is always maintained at a stable level, which is beneficial to extend the life of the gas steam boiler; fifth, a high-temperature water temperature gauge temperature sensor is set at the end of the waste heat recovery device to display the temperature so as to adjust the set temperature of the valley electricity preheating in the preheating water tank to ensure waste heat recovery and high-temperature water supply of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural diagram of a combined steam generating device with a preheating water tank according to the present invention.

[0032] The above drawings are marked as follows: steam production system 1, steam boiler 11, gas steam boiler 111, burner 1111, waste heat recovery device 1112, waste heat recovery device inlet 11121, waste heat recovery device outlet 11122, flue 1113, water level meter 112, steam outlet 113, safety valve 114, variable frequency feed water pump 12, temperature gauge 13, preheating water inlet pipe 14, check valve 15, high temperature water temperature gauge 16, temperature sensor 17, high temperature water check valve 18, preheating water inlet 141, normal pressure heating water system 2, preheating electromagnetic boiler 21, preheating electromagnetic boiler water inlet 211, preheating electromagnetic boiler water outlet 212, circulating water outlet pipe 213, preheating water tank 22, circulating water inlet pipe 221, circulating water pump 23, solenoid valve 24, cold water pipe 25, manhole 26, float valve 27, electric control box 28, soft water processor 3;

[0033] The raw water inlet direction is A, the softened water flow direction is B, the preheated water circulation direction is C, the preheated water flow direction into the gas steam boiler is D; the flue gas flow direction is E. DETAILED DESCRIPTION

[0034] Example 1

[0035] See also Figure 1 A combined steam generating device with a preheating water tank is composed of a soft water processor 3, a normal pressure water heating system 2 and a steam production system 1 which are connected in series through pipelines from the water inlet to the steam outlet; the steam production system 1 includes a steam boiler 11, a variable frequency water supply pump 12, a check valve 15 and a preheating water inlet pipeline 14; the normal pressure water heating system 2 includes a preheating electromagnetic boiler 21, a preheating water tank 22, a circulating water pump 23, an electromagnetic valve 24, and a cold water pipeline 25. The steam boiler 11 adopts a gas steam boiler 111. The preheating electromagnetic boiler 21 adopts a three-phase power frequency induction electromagnetic boiler or a single-phase power frequency induction electromagnetic boiler.

[0036] The outlet of the soft water processor 3 is connected to the upper part of the preheating water tank 22 through a cold water pipe 25 , and a solenoid valve 24 is provided on the cold water pipe 25 .

[0037] A manhole 26 and a float valve 27 are provided on the upper portion of the preheating water tank 22 , and the float valve 27 and the solenoid valve 24 are electrically connected.

[0038] The lower side of the preheating water tank 22 is connected to the preheating electromagnetic boiler water inlet 211 at the lower part of the preheating electromagnetic boiler 21 through a circulating water inlet pipe 221 , and a circulating water pump 23 is provided on the circulating water inlet pipe 221 .

[0039] The preheating electromagnetic boiler water outlet 212 at the top of the preheating electromagnetic boiler 21 is connected to the upper part of the preheating water tank 22 through a circulating water outlet pipe 213 .

[0040] The lower part of the preheating water tank 22 away from the preheating electromagnetic boiler 21 enters the preheating water inlet 141 on the upper part of the gas steam boiler 111 through the preheating water inlet pipe 14, and the preheating water inlet pipe 14 is provided with a thermometer 13, a variable frequency water pump 12 and a check valve 15 in sequence.

[0041] The gas steam boiler 111 is provided with a water level meter 112 , a steam outlet 113 and a safety valve 114 , and the water level meter 112 is electrically connected to the variable frequency water feed pump 12 .

[0042] Furthermore, the gas steam boiler 111 comprises a burner 1111 and a waste heat recovery device 1112; the burner 1111 is arranged at the bottom of the gas steam boiler 111, and the waste heat recovery device 1112 is arranged in a flue 1113 of the gas steam boiler 111;

[0043] The preheating water inlet pipe 14 enters the waste heat recovery device 1112 from the waste heat recovery device inlet 11121 of the waste heat recovery device 1112, is coiled and arranged in the waste heat recovery device 1112, and then enters the gas steam boiler 111 from the preheated water inlet 141 at the upper part of the gas steam boiler 111 through the waste heat recovery device outlet 11122;

[0044] A high-temperature water thermometer 16 , a temperature sensor 17 and a high-temperature water check valve 18 are provided on the preheating water inlet pipe 14 from the waste heat recovery device outlet 11122 to the preheating water inlet 141 . The temperature sensor 17 is electrically connected to the electric control box 28 of the preheating electromagnetic boiler 21 .

[0045] The inlet 11121 of the waste heat recovery device is located at the end of the flue 1113 , and the outlet 11122 of the waste heat recovery device is located at the starting end of the flue 1113 .

[0046] Furthermore, the preheating electromagnetic boiler 21 and the electric control box 28 of the preheating electromagnetic boiler 21 are installed on the same base, and the PLC control program in the electric control box 28 realizes fully automatic intelligent control of the opening and closing of the electromagnetic boiler 21; the preheating electromagnetic boiler 21 is a three-phase industrial frequency induction electromagnetic boiler.

[0047] The preheating water tank 22 is further insulated on six sides.

[0048] See also Figure 1 , the medium flow direction of this embodiment is: external water enters the soft water processor 3 from A for softening treatment; the softened water enters the preheating electromagnetic boiler 21 in the cold water pipe 25 along the direction of B, and enters the lower part of the preheating electromagnetic boiler 21 along the direction of C in the circulating water inlet pipe 221; the preheated water enters the upper part of the preheating water tank 22 along the direction of C in the circulating water outlet pipe 213 to form a preheating cycle; the preheated water enters the upper part of the gas steam boiler 111 along the direction of D in the preheating water inlet pipe 14, is heated by the waste heat recovery device 1112, and then enters the gas steam boiler 111; the smoke of the gas steam boiler 111 is discharged to the outside along the direction of E.

[0049] Example 2

[0050] The difference between the steam generating device of Example 2 and Example 1 is that the steam boiler 11 adopts a resistance boiler in an electric boiler, and there is no waste heat recovery device 1112 in the steam production system 1. The rest is the same as Example 1.

[0051] Example 3

[0052] The method for producing steam using the combined steam generating device with a preheating water tank described in Example 1 comprises the following steps:

[0053] Step 1: Input the softened incoming water into the preheating water tank 22 through the cold water pipe 25. The float valve 27 and the solenoid valve 24 work together to keep the preheating water tank 22 at a reasonable water level.

[0054] Step 2: At night, the preheating electromagnetic boiler 21 is started by using off-peak electricity, and the circulating water pump 23 circulates the water in the preheating water tank 22 into the preheating electromagnetic boiler 21 for heating.

[0055] Step 3: during the day, the burner 1111 of the gas steam boiler 111 is turned on, and the flue gas in the flue 1113 further heats the hot water in the waste heat recovery device 1112, and the hot water enters the gas steam boiler 111 to generate steam.

[0056] Comparative Example

[0057] A combined steam generating device with a preheating water tank in Example 1 was operated for one month under the same operating conditions as a conventional gas steam boiler, and a comparative test was performed: the outlet temperature of the softener was 49°C, and the water temperature entering the steam boiler in the conventional gas steam boiler system was 49°C; the water temperature entering the steam boiler after preheating in the present invention was 89°C. The relevant test data are shown in the table below.

[0058]

[0059] As can be seen from the above table, the boiler efficiency of the present invention reaches 84.62%, which is much higher than the boiler efficiency of 75.49% in the ordinary gas steam boiler system. Even though the present invention requires an electricity consumption of 50.37 (KWh / t) per ton of steam, due to the mandatory environmental protection, the economy of the present invention is still very significant.

Claims

1. A combined steam generating device with a preheating water tank, comprising a water softener (3), a normal pressure water heating system (2) and a steam generating system (1) which are sequentially connected in series through a pipeline from a water inlet to a steam outlet; Features: The steam production system (1) comprises a steam boiler (11), a variable frequency water supply pump (12), a check valve (15) and a preheating water inlet pipe (14); the steam boiler (11) is provided with a water level meter (112), a steam outlet (113) and a safety valve (114), and the water level meter (112) is electrically connected to the variable frequency water supply pump (12); the normal pressure water heating system (2) comprises a preheating electromagnetic boiler (21), a preheating water tank (22), a circulating water pump (23), an electromagnetic valve (24), and a cold water pipe (25); the preheating electromagnetic boiler (21) and an electric control box (28) of the preheating electromagnetic boiler (21) are installed on the same base; the preheating electromagnetic boiler (21) is a three-phase industrial frequency induction electromagnetic boiler, or a single-phase industrial frequency induction electromagnetic boiler; The outlet of the soft water treatment device (3) is connected to the upper part of the preheating water tank (22) through a cold water pipe (25), and a solenoid valve (24) is provided on the cold water pipe (25); The lower side of the preheating water tank (22) is connected to the preheating electromagnetic boiler water inlet (211) at the lower part of the preheating electromagnetic boiler (21) through a circulating water inlet pipe (221), and a circulating water pump (23) is provided on the circulating water inlet pipe (221); The preheating electromagnetic boiler water outlet (212) at the top of the preheating electromagnetic boiler (21) is connected to the upper part of the preheating water tank (22) through a circulating water outlet pipe (213); The lower part of the preheating water tank (22) away from the preheating electromagnetic boiler (21) enters the preheating water inlet (141) at the upper part of the steam boiler (11) through the preheating water inlet pipe (14), and the preheating water inlet pipe (14) is connected in sequence to a temperature gauge (13), a variable frequency water supply pump (12) and a check valve (15). The steam boiler (11) is a gas-fired steam boiler (111), comprising a burner (1111) and a waste heat recovery device (1112); the burner (1111) is arranged at the bottom of the gas-fired steam boiler (111), and the waste heat recovery device (1112) is arranged in the flue (1113) of the gas-fired steam boiler (111); The preheating water inlet pipe (14) enters the waste heat recovery device (1112) from the waste heat recovery device inlet (11121) of the waste heat recovery device (1112), then winds through the waste heat recovery device (1112), passes through the waste heat recovery device outlet (11122), and enters the gas steam boiler (111) from the preheating water inlet (141) at the upper part of the gas steam boiler (111); the waste heat recovery device inlet (11121) is located at the end of the flue (1113), and the waste heat recovery device outlet (11122) is located at the starting end of the flue (1113); a high-temperature water temperature gauge (16), a temperature sensor (17) and a high-temperature water check valve (18) are provided in the preheating water inlet pipe (14) from the waste heat recovery device outlet (11122) to the preheating water inlet (141); the temperature sensor (17) is electrically connected to the electric control box (28) of the preheating electromagnetic boiler (21).

2. A combined steam generating device with a preheating water tank according to claim 1, characterized in that: A manhole (26) and a float valve (27) are provided on the upper portion of the preheating water tank (22), and the float valve (27) and the solenoid valve (24) are electrically connected.

3. A combined steam generating device with a preheating water tank according to claim 1, characterized in that: The preheating water tank (22) has six sides which are insulated and heat-preserved.

4. A combined steam generating device with a preheating water tank according to claim 1, characterized in that: The steam boiler (11) is an electric boiler; the electric boiler is a resistance boiler or an electromagnetic boiler.

5. A method for producing steam, characterized in that: The method for producing steam using a combined steam generating device with a preheating water tank as claimed in claim 1 comprises the following steps: Step 1: Softened incoming water is fed into the preheating water tank (22) through the cold water pipe (25); the float valve (27) and the solenoid valve (24) work together to maintain a reasonable water level in the preheating water tank (22); Step 2: At night, the preheating electromagnetic boiler (21) is started by using off-peak electricity, and the circulating water pump (23) circulates the water in the preheating water tank (22) into the preheating electromagnetic boiler (21) for heating; Step 3: during the day, the burner (1111) of the gas steam boiler (111) is turned on, and the flue gas in the flue (1113) further heats the hot water in the waste heat recovery device (1112), and the hot water enters the gas steam boiler (111) to generate steam.

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