Flameless gas boiler

Abstract

The application relates to a flameless gas boiler, which comprises a gas pipeline, a boiler body and a first energy saver; a semi-adiabatic hearth is arranged in the boiler body; a gas inlet end of the gas pipeline is suitable for introducing gas; the gas pipeline is provided with a combustion air inlet suitable for introducing combustion air and an external circulating flue gas inlet suitable for introducing flue gas; so that the gas in the gas pipeline is mixed with the combustion air and the flue gas introduced into the gas pipeline to form mixed gas; the gas outlet end of the gas pipeline is in communication with the internal cavity of the semi-adiabatic hearth and is suitable for sending the mixed gas into the internal cavity of the semi-adiabatic hearth; a high-temperature energy residence device is arranged in the semi-adiabatic hearth and is suitable for high-temperature oxidation of the mixed gas flowing through the high-temperature energy residence device; and the gas outlet of the semi-adiabatic hearth is connected with the external circulating flue gas inlet through the first energy saver. The application can reduce the contact probability of oxygen and nitrogen and reduce the generation of nitrogen oxides.

Description

Technical Field

[0001] This application relates to the field of combustion boiler technology, and more particularly to a flameless gas-fired boiler. Background Technology

[0002] Ordinary gas-fired boilers produce extremely high levels of nitrogen oxides (NOx) in their exhaust gases during combustion. The NO generated during combustion is easily oxidized into NO2 after being released into the atmosphere, which in turn forms acid rain and acid fog, seriously threatening human health. Therefore, it is urgent to retrofit gas-fired boilers to reduce nitrogen content.

[0003] This application proposes a flameless gas-fired boiler suitable for reducing the release of nitrogen oxides during gas combustion. Summary of the Invention

[0004] In view of this, this application proposes a flameless gas-fired boiler.

[0005] According to one aspect of this application, a flameless gas-fired boiler is provided, comprising: a gas pipeline, a boiler body, and a first economizer;

[0006] The boiler body is equipped with a semi-insulated furnace.

[0007] The gas pipeline has an inlet for introducing gas, and an external circulation flue gas inlet for introducing combustion air and flue gas for introducing flue gas. This allows the gas in the gas pipeline to mix with the combustion air and flue gas introduced into the gas pipeline to form a mixed gas. The outlet of the gas pipeline is connected to the internal cavity of the semi-insulated furnace to deliver the mixed gas into the interior of the semi-insulated furnace.

[0008] The semi-insulated furnace is equipped with a high-temperature energy retention device, which is suitable for high-temperature oxidation of mixed gas flowing through the high-temperature energy retention device;

[0009] The outlet of the semi-insulated furnace is connected to the inlet of the external circulating flue gas through the first economizer.

[0010] In one possible implementation, a mixer is provided at the outlet of the gas pipeline to mix the gas, combustion air and flue gas in the gas pipeline.

[0011] In one possible implementation, a gas distributor is also included, with the outlet of the mixer connected to the inlet of the gas distributor.

[0012] In one possible implementation, a deflaming guide pipe is also included, which is located between the gas distributor and the boiler body and communicates with the internal cavity of the semi-insulated furnace.

[0013] In one possible implementation, the de-flame guide duct is equipped with a secondary air inlet.

[0014] In one possible implementation, the high-temperature energy retention device is formed by stacking thermal shock resistant materials.

[0015] One possible implementation also includes: an air duct and an external circulation duct; a combustion air inlet connected to the air duct, and an external circulation flue gas inlet connected to the external circulation duct.

[0016] One possible implementation also includes: a second energy-saving device;

[0017] The outlet of the first energy-saving device is connected to the inlet of the second energy-saving device, and the outlet of the second energy-saving device is connected to the inlet of the external circulation flue gas through an external circulation pipe.

[0018] In one possible implementation, it also includes: an air preheater; the air preheater is provided at one end of the air duct into which the combustion air is injected, and the air preheater is suitable for preheating the combustion air.

[0019] In one possible implementation, the outlet of the second energy-saving device is connected to the medium inlet of the air preheater via a pipe, and the medium outlet of the air preheater is connected to the external circulation pipe.

[0020] Beneficial effects: Gas pipelines are suitable for transporting natural gas and other fuel gases. The combustion air inlet of the gas pipeline is used to introduce combustion air from the outside into the gas pipeline. The external circulation flue gas inlet of the gas pipeline is used to circulate the flue gas output from the semi-insulated furnace back into the gas pipeline. The fuel gas in the gas pipeline mixes with the combustion air and flue gas to form a mixed gas. This mixed gas is transported into the semi-insulated furnace for high-temperature oxidation. By utilizing the split high-temperature energy retention device in the semi-insulated furnace, the mixed gas can achieve flameless combustion in the semi-insulated furnace, which is also known as high-temperature oxidation or flameless oxidation. The temperature of the mixed gas combustion or oxidation mainly depends on the heat carried by the circulating flue gas. This application replaces flame combustion with high-temperature oxidation, and uses a high-temperature environment and a high-temperature energy carrier (high-temperature energy retention device) instead of an electric spark or open flame to activate the oxidation reaction chain. This allows the gas to undergo complete flameless oxidation or combustion in a high-temperature environment, completely eliminating the outer flame, which is the hottest part of the basic flame structure, thus eliminating the reaction driving force for nitrogen oxides. Since the exhaust gas is recirculated into the gas pipeline, large amounts of exhaust gas are avoided from being emitted into the external environment. At the same time, the exhaust gas can dilute the oxygen and gas content in the gas pipeline, effectively reducing the probability of contact between oxygen and nitrogen, thereby further reducing the generation of nitrogen oxides.

[0021] Other features and aspects of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0023] Figure 1 This diagram illustrates the structural connection relationship of a flameless gas-fired boiler according to an embodiment of this application.

[0024] Figure 2 Show Figure 1 A magnified view of a portion of the image;

[0025] Figure 3 Show Figure 1 A magnified view of a portion of the image;

[0026] Figure 4 This application shows a top view of the boiler body according to an embodiment of the present application;

[0027] Figure 5 This is a front view of the boiler body according to an embodiment of this application;

[0028] Figure 6 Show Figure 5 A partial view;

[0029] Figure 7 A side view of the boiler body according to an embodiment of this application is shown;

[0030] Figure 8 A cross-sectional view of the boiler body according to an embodiment of this application is shown;

[0031] Figure 9 Show Figure 8 A partial view.

[0032] 100 Gas pipeline, 130 Combustion air inlet, 140 External circulation flue gas inlet, 150 Mixer, 151 Oxygen concentration detector, 160 Dry flame arrester, 161 Thermometer, 170 Expansion joint, 190 Flame extinguishing guide pipe, 191 Secondary air inlet, 180 Gas distributor, 200 Boiler body, 210 Semi-insulated furnace, 211 High-temperature energy retention device, 600 First economizer, 700 External circulation pipeline, 720 First fan, 800 Air preheater, 90 Air pipeline 0. Secondary gas pipeline 112, second mixer 115, secondary air intake pipeline 950, softened water inlet pipe 610, softened water outlet pipe 620, steam pipeline 810, second energy saver 630, second fan 940, filter 920, blower 910, front heat dissipation shell 530, rear heat dissipation shell 500, isolation layer 510, lower header 280, upper header 270, upper drum 300, lower drum 400, auxiliary spray gun 219, main combustion temperature sensor 216, flame sensor 217. Detailed Implementation

[0033] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0034] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application or to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0036] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0037] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0038] Figure 1 This diagram illustrates the connection relationship of a flameless gas-fired boiler according to an embodiment of this application. Figure 2 Show Figure 1 A magnified view of a portion of the image; Figure 3 Show Figure 1 A magnified view of a portion of the image; Figure 4 This application shows a top view of the boiler body according to an embodiment of the present application; Figure 5 This is a front view of the boiler body according to an embodiment of this application; Figure 6 Show Figure 5 A partial view; Figure 7 A side view of the boiler body according to an embodiment of this application is shown; Figure 8A cross-sectional view of the boiler body according to an embodiment of this application is shown; Figure 9 Show Figure 8 A partial view. For example... Figure 1 As shown, this flameless gas-fired boiler includes: a gas pipeline 100, a boiler body 200, and a first economizer 600; Figure 8 As shown, the boiler body 200 is provided with a semi-insulated furnace 210; the inlet end of the gas pipeline 100 is suitable for introducing gas, and the outlet end of the gas pipeline 100 is connected to the cavity of the semi-insulated furnace 210; the gas pipeline 100 is provided with a combustion air inlet 130 for introducing combustion air and an external circulation flue gas inlet 140 for introducing flue gas; so that the gas in the gas pipeline 100 is mixed with the combustion air and flue gas introduced into the gas pipeline 100 to form a mixed gas; the semi-insulated furnace 210 is provided with a high-temperature energy retention device 211, which is suitable for high-temperature oxidation of the mixed gas flowing through the high-temperature energy retention device 211; the outlet of the semi-insulated furnace 210 is connected to the external circulation flue gas inlet 140 through a first energy saver 600.

[0039] It should be noted that the gas pipeline 100 is suitable for transmitting natural gas and other fuel gases. The combustion air inlet 130 of the gas pipeline 100 is used to introduce combustion air from the outside into the gas pipeline 100. The external circulating flue gas inlet 140 of the gas pipeline 100 is used to circulate the flue gas output from the semi-insulated furnace 210 back into the gas pipeline 100. The fuel gas in the gas pipeline 100 mixes with the combustion air and flue gas to form a mixed gas. This mixed gas is transported to the semi-insulated furnace 210 for high-temperature oxidation. The split high-temperature energy retention device 211 in the semi-insulated furnace 210 enables the mixed gas to achieve flameless combustion in the semi-insulated furnace 210, which is also called high-temperature oxidation or flameless oxidation. The temperature of the mixed gas combustion or oxidation mainly depends on the heat carried by the circulating flue gas. This application replaces flame combustion with high-temperature oxidation, and uses a high-temperature environment and a high-temperature energy carrier (high-temperature energy retention device 211) instead of an electric spark or open flame to activate the oxidation reaction chain. This allows the gas to undergo complete flameless oxidation or combustion in a high-temperature environment, completely eliminating the outer flame, which is the hottest part of the basic flame structure, thereby eliminating the reaction driving force of nitrogen oxides. Since the exhaust gas is recirculated into the gas pipeline 100, it avoids the large-scale emission of flue gas into the external environment. At the same time, the flue gas can dilute the oxygen content and gas content in the gas pipeline 100, effectively reducing the probability of contact between oxygen and nitrogen, thereby further reducing the generation of nitrogen oxides.

[0040] In one possible implementation, a mixer 150 is provided at one end of the gas pipeline 100 connecting to the boiler body 200, and the mixer 150 is located at the rear end of the combustion air inlet 130 and the external circulating flue gas inlet 140, so as to mix the gas, combustion air and flue gas in the gas pipeline 100. Figure 1 and Figure 4 As shown, the mixer 150 is installed on the gas pipeline 100. The mixer 150 is suitable for thoroughly mixing the flowing flue gas, fuel gas, and combustion air to achieve uniform mixing, thereby effectively diluting the oxygen and fuel gas content in the gas pipeline 100. Preferably, the mixer 150 is a static mixer.

[0041] In one possible implementation, a gas distributor 180 is also included, with the outlet of the mixer 150 connected to the inlet of the gas distributor 180. It should be noted that if the flow rate of the mixed gas is large and it is directly injected into the semi-insulated furnace 210, it is easy for the mixed gas to be unable to be evenly distributed in the semi-insulated furnace 210. Therefore, before the mixed gas enters the semi-insulated furnace 210 of the boiler body 200, the gas distributor 180 can cut and disperse the mixed gas and slightly reduce the flow rate of the mixed gas, so that the mixed gas flowing through the gas distributor 180 is evenly distributed across the entire cross section, and the mixed gas fully enters the semi-insulated furnace 210, thereby improving the uniformity of the mixed gas distribution in the semi-insulated furnace 210. In summary, designing a uniform mixed airflow allows the combustion temperature field to be evenly distributed throughout the semi-insulated furnace 210, ensuring that the temperature at each point of the oxidation reaction is consistent. There is no flame or localized maximum temperature, nor is there a minimum temperature in the cold wall. The temperature of the furnace wall at any point within the semi-insulated furnace 210 is greater than 800℃, avoiding incomplete combustion of the mixed gas. This significantly reduces the carbon monoxide content in the exhaust gas, even bringing it close to zero, achieving complete combustion. At the same time, by eliminating the combustion flame and its maximum temperature, the generation of dynamic nitrogen oxides is effectively suppressed.

[0042] In one possible implementation, such as Figure 1 and Figure 4 As shown, it also includes: a flameout guide pipe 190, which is located between the gas distributor 180 and the boiler body 200, and further, as... Figure 4 As shown, one side of the gas distributor 180 extends into one end of the deflaming guide pipe 190, and the other end of the deflaming guide pipe 190 is fixed to the front wall 214 of the boiler body 200 and communicates with the interior of the semi-insulated furnace 210. The gas distributor 180 ensures that the mixed gas is evenly distributed when it enters the deflaming guide pipe 190. The deflaming guide pipe 190 increases the transmission length and reduces the probability of backfire in the premixing section, thereby ensuring the safety of the premixing section.

[0043] Furthermore, the length of the deflaming guide pipe 190 is greater than 600 mm. The deflaming guide pipe 190 is suitable for extending the distance between the gas distributor 180 and the boiler body 200, forming a deflaming section of at least 600 mm. After the mixed gas crosses the deflaming guide pipe 190 and enters the semi-insulated furnace 210, it achieves flameless oxidation or combustion under the activation conditions of the high-temperature energy retention device 211 and the high-temperature environment within the semi-insulated furnace 210. Preferably, the length of the deflaming guide pipe 190 is in the range of 0.6-1.5 meters.

[0044] Furthermore, the deflaming guide pipe 190 consists of a coaxial sleeve and a refractory layer. One end of the sleeve is welded and fixed to the front wall 214 of the boiler body 200. The refractory layer is located inside the sleeve, and the refractory layer is made of a refractory material with high hardness. Due to the high flow velocity of the mixed gas inside the deflaming guide pipe 190, a relatively high-hardness refractory layer is provided on the inner wall of the channel to prevent the gas from eroding and damaging it. Preferably, the refractory layer is made of high-alumina castable or high-alumina preform with a temperature resistance of up to 1200℃.

[0045] Furthermore, a high-temperature resistant insulation layer is filled between the refractory layer and the sleeve. Preferably, the high-temperature resistant insulation layer is made of zirconium-containing aluminum silicate or ceramic fiber, and is also required to withstand temperatures up to 1200℃.

[0046] In one possible implementation, such as Figure 4 As shown, the flameout guiding duct 190 is equipped with a secondary air inlet 191. The secondary air inlet 191 connects to the flameout guiding duct 190 to introduce combustion air into the flameout guiding duct 190. It should be noted that combustion air is only introduced into the secondary air inlet 191 when the combustion air content in the semi-insulated furnace 210 is insufficient. The supplemented combustion air enters the flameout guiding duct 190 through the secondary air inlet 191 for secondary premixing. It is important to note that adding a secondary air inlet 191 to the flameout guiding duct ensures both front-end safety and the necessary, or even excessive, combustion air volume for complete combustion.

[0047] In one possible implementation, it also includes: a dry flame arrester 160, wherein the outlet end of the mixer 150 is connected to one end of the dry flame arrester 160 via a pipe, and the mixer 150 and the dry flame arrester 160 are arranged sequentially along the flow direction of the mixed gas; the dry flame arrester 160 is a new type of fire-fighting equipment that plays a role in blocking and dispersing flames and suppressing fire sources, thereby preventing the gas pipeline 100 from catching fire.

[0048] In one possible implementation, it further includes: an expansion joint 170, which is disposed between the dry flame arrester 160 and the gas distributor 180; furthermore, the expansion joint 170 is a detachable expansion joint 170, and the flanges at both ends of the detachable expansion joint 170 are detachably connected to the flanges of the dry flame arrester 160 and the gas distributor 180, respectively; it should be noted that the expansion joint 170 can overcome the offset caused by different axial directions of the pipeline connection within a certain angle, which can facilitate the installation and disassembly of the pipeline, and can be disassembled at any time for cleaning, maintenance and repair of the dry flame arrester 160 and the gas distributor 180.

[0049] In summary, the gas pipeline 100 is connected to the boiler body 200 at one end by a mixer 150, a dry flame arrester 160, an expansion joint 170, a gas distributor 180, and a flameout guide pipe 190, which are arranged and connected in sequence along the flow direction of the mixed gas.

[0050] Because the mixed gas in the gas pipeline 100 has flame propagation characteristics, the high-temperature radiation of the semi-insulated furnace 210 causes the furnace body to heat up and backfire. If the flame returns to the gas pipeline 100, it can easily cause detonation and explosion. This has been a serious bottleneck in the development history of traditional premixed combustion technology. The application proposes to increase the distance between the gas pipeline 100 and the semi-insulated furnace 210 by setting up a flame-removing guide pipe 190. If the semi-insulated furnace 210 catches fire, it can prevent the flame from directly entering the gas pipeline 100. Furthermore, since a dry flame arrester 160 is installed between the gas pipeline 100 and the flame-removing guide pipe 190, the flame can be effectively intercepted, preventing the flame from propagating into the gas pipeline 100 and causing a detonation accident. This improves the safety index and protection performance of the entire equipment during operation, demonstrating the advantages of premixed combustion technology.

[0051] In one possible implementation, such as Figure 2 As shown, an oxygen concentration detector 151 is installed on the pipeline between the mixer 150 and the dry flame arrester 160. The detection end of the oxygen concentration detector 151 is located inside the pipeline between the mixer 150 and the dry flame arrester 160 to detect the oxygen content in the mixed gas. When the oxygen content is insufficient, oxygen is promptly added to the flameout guide pipeline 190 through the secondary air inlet 191. When the oxygen content exceeds the standard, the flow rate of the introduced combustion air is promptly adjusted and reduced to keep the oxygen content in the mixed gas within a safe value (content 10%).

[0052] In one possible implementation, such as Figure 2 As shown, a thermometer 161 is provided on the pipe between the dry flame arrester 160 and the expansion joint 170, and the probe end of the thermometer 161 is located inside the pipe, which is suitable for detecting the temperature of the mixed gas before entering the gas distributor 180.

[0053] In one possible implementation, such as Figure 2 As shown, the gas pipeline 100 is equipped with a shut-off valve 103, a first gas regulating valve 110, a first gas flow meter 111, and two first shut-off valves 120. The shut-off valve 103, the first gas regulating valve 110, the first gas flow meter 111, and the two first shut-off valves 120 are arranged sequentially along the gas flow direction in the gas pipeline 100, and the two first shut-off valves 120 are located at the front end of the combustion air inlet 130 and the external circulating flue gas inlet 140. The first gas regulating valve 110 is used to control the gas flow rate in the gas pipeline 100 at any time, and the first gas flow meter 111 is used to detect the gas flow rate in the gas pipeline 100. The two first shut-off valves 120 are used to control the opening and closing of the gas pipeline 100, thereby controlling the gas supply.

[0054] In one possible implementation, such as Figure 2 As shown, the gas pipeline 100 is also equipped with a first pressure gauge 101, a thermometer 102 and a second pressure gauge 121; the first pressure gauge 101 and the thermometer 102 are arranged adjacent to each other and are suitable for detecting the gas pressure and gas temperature in the gas pipeline 100 respectively; the second pressure gauge 121 is arranged between the two first shut-off valves 120.

[0055] In one possible implementation, the gas pipeline 100 is further provided with a venting pipeline 123, on which a safety valve 122 is provided to regulate the opening and closing of the venting pipeline 123. The venting pipeline 123 is suitable for timely emptying of the gas in the gas pipeline 100 under special circumstances.

[0056] In one possible implementation, the system further includes: an air duct 900, one end of which is connected to a combustion air inlet 130, for supplying combustion air into the gas pipeline 100; and a first oxygen regulating valve 901 is provided on the air duct 900 to regulate the flow rate of the combustion air within it. When the oxygen content exceeds the limit, the first oxygen regulating valve 901 is adjusted in a timely manner to reduce the amount of combustion air entering the gas pipeline 100, thereby reducing the oxygen content in the gas mixture. In summary, the first oxygen regulating valve 901 is used to strictly control the oxygen content in the gas mixture to not exceed 10%.

[0057] Furthermore, such as Figure 1 As shown, an air preheater 800 is installed at one end of the air duct 900 where combustion air is injected. It should be noted that the air preheater 800 is one of the energy-saving devices in this application. Preheating the combustion air can save energy and plays a very important role in improving thermal efficiency. Furthermore, preheating the combustion air is more suitable for low-calorific-value gases. The specific preheating temperature can be determined as needed. Generally, for low-calorific-value and difficult-to-burn gases, the preheating temperature can be increased as needed to meet normal combustion requirements.

[0058] In one possible implementation, the system further includes: an external circulation pipe 700, one end of which is connected to the flue gas output from the semi-insulated furnace 210, and the other end of which is connected to an external circulation flue gas inlet 140, suitable for inputting flue gas into the gas pipeline 100; and a flue gas regulating valve 710 is provided on the external circulation pipe 700 to regulate the flow rate of the flue gas within the external circulation pipe 700. It should be noted that the temperature of the flue gas circulating into the gas pipeline 100 is not greater than 100℃; the flow rate of the flue gas within the external circulation pipe 700 is regulated according to the combustion temperature within the semi-insulated furnace 210, and further, the flow rate of the flue gas within the external circulation pipe 700 is regulated based on the criterion that the combustion temperature within the semi-insulated furnace 210 is not greater than 1100℃.

[0059] The external circulation pipe 700 is equipped with a first fan 720, which is used to provide power for the flow of flue gas, so that the flue gas can be smoothly sent into the gas pipe 100.

[0060] In one possible implementation, such as Figure 4 As shown, the high-temperature energy retention device 211 is a masonry formed by the construction of thermal shock resistant materials. Furthermore, the thermal shock resistant materials can be materials with excellent thermal shock resistance and high refractoriness, such as high-alumina bricks, alumina bricks, and silicon carbide bricks. Preferably, the high-temperature energy retention device 211 is a masonry formed by the construction of multiple high-alumina bricks, and the masonry has a cuboid structure.

[0061] In one possible implementation, the ratio of the volume of the high-temperature energy retention device 211 to the total volume of the semi-insulated furnace 210 ranges from 1 / 3 to 1 / 2. It should be noted that the specific volume of the high-temperature energy retention device 211 is determined based on the mass of the combustion gas. Generally, for combustion gases with higher calorific value, the volume of the high-temperature energy retention device 211 is smaller; as the calorific value decreases, the volume of the high-temperature energy retention device 211 increases.

[0062] In one possible implementation, such as Figure 8As shown, the main body of the semi-insulated furnace 210 has a cylindrical structure, and its end face is trapezoidal. The furnace wall 260 of the semi-insulated furnace 210 is made of high-alumina refractory material; the furnace wall 260 is used to isolate the furnace from the front heat dissipation shell 530 of the boiler body 200 and prevent heat transfer, thus preventing the membrane water-cooled wall from absorbing heat from the semi-insulated furnace 210. During normal operation, the temperature of the semi-insulated furnace 210 (the temperature inside the combustion chamber) is controlled above 800℃, ensuring that the temperature of the entire semi-insulated furnace 210, including its furnace wall 260, is greater than 800℃, and the temperature of oxidation or flameless combustion is controlled below 1100℃; eliminating the cold wall effect and avoiding the interruption of the reaction chain and incomplete combustion caused by the cold wall effect. If the nitrogen oxide emission value is to be reduced to zero, the combustion temperature can be controlled below 1000℃.

[0063] In one possible implementation, such as Figure 2 As shown, the boiler body 200 has an auxiliary air inlet 201 for connecting the auxiliary gas pipeline 112, and the auxiliary air inlet 201 is connected to the interior of the semi-insulated furnace 210, which is suitable for injecting gas into the semi-insulated furnace 210 through the auxiliary air inlet 201.

[0064] In one possible implementation, such as Figure 2 As shown, it also includes: an auxiliary gas pipeline 112, one end of which is suitable for being injected with gas, and the other end of which is connected to the auxiliary air inlet 201 of the semi-insulated furnace 210; the auxiliary gas pipeline 112 is also provided with a combustion air inlet and an external circulation flue gas inlet, the combustion air inlet is connected to the auxiliary air pipeline 930 to receive combustion air, and the external circulation flue gas inlet is connected to the external circulation pipeline 700 to receive flue gas.

[0065] A second oxygen regulating valve 931 is provided on the auxiliary air duct 930. The second oxygen regulating valve 931 is used to regulate the air flow in the auxiliary air duct 930.

[0066] In one possible implementation, a second mixer 115 is provided on the auxiliary gas pipeline 112; and the second mixer 115 is located at the rear end of the combustion air inlet and the external circulating flue gas inlet. The second mixer 115 is suitable for mixing the combustion air, flue gas and gas in the auxiliary gas pipeline 112 to improve the uniformity of the mixed gas entering the semi-insulated furnace 210.

[0067] In one possible implementation, a gas distributor is also provided at one end of the auxiliary gas pipeline 112 connected to the auxiliary gas inlet 201 to improve the uniformity of gas entering the semi-insulated furnace 210.

[0068] In one possible implementation, the auxiliary gas pipeline 112 is equipped with a shut-off valve 152, a second gas flow meter 113, a third pressure gauge 154, and two second shut-off valves 114. The shut-off valve 152, the second gas flow meter 113, and the two second shut-off valves 114 are arranged sequentially along the flow direction of the gas in the auxiliary gas pipeline 112, and the second shut-off valves 114 are located upstream of the combustion air inlet and the external circulating flue gas inlet. The second gas flow meter 113 is used to detect the flow rate of the gas in the auxiliary gas pipeline 112; the shut-off valve 152 and the two second shut-off valves 114 are used to control the opening and closing of the auxiliary gas pipeline 112.

[0069] In one possible implementation, the auxiliary gas pipeline 112 is also provided with a venting pipeline 155, and a safety valve 156 is provided on the venting pipeline 155 to regulate the opening and closing of the venting pipeline 155. The venting pipeline 155 is suitable for timely emptying of the gas in the auxiliary gas pipeline 112 under special circumstances.

[0070] It should be noted that this application sets up two gas pipelines: a main gas pipeline 100 (connecting to the main distributor) and an auxiliary gas pipeline 112 (connecting to the auxiliary distributor). In the initial state, high-temperature mixed gas is first supplied to the semi-insulated furnace 210 through the auxiliary gas pipeline 112 for combustion or oxidation to raise the temperature of the semi-insulated furnace 210 to a certain value. Then, the auxiliary gas pipeline 112 is shut off (or can continue to operate), and the main gas pipeline 100 is then put into operation as the heat source for the main energy output. This design can reduce the safety risk of the boiler body 200 (the probability of flameout due to uncontrollable factors) to zero.

[0071] Furthermore, the inlet end of the auxiliary gas pipeline 112 is connected to the main gas pipeline 100, and the inlet end of the main gas pipeline 100 is equipped with a third gas flow meter 116.

[0072] In one possible implementation, such as Figure 1 As shown, it also includes: a secondary air intake pipe 950, one end of which is suitable for introducing combustion air, and the other end of which is connected to the secondary air intake port 191 of the defrost guide pipe 190; and a third oxygen regulating valve 951 is provided on the secondary air intake pipe 950, which is suitable for regulating the flow rate of combustion air in the secondary air intake pipe 950 so that when the content of combustion air in the semi-insulated furnace 210 is insufficient, the secondary air intake pipe 950 can supplement combustion air; the air intake end of the secondary air intake pipe 950 and the air intake end of the auxiliary air pipe 930 are both connected to the air pipe 900 so that they can both be connected to the combustion air preheated by the air preheater 800.

[0073] In one possible implementation, the air inlet of the first economizer 600 is connected to the outlet of the boiler body 200 (the air outlet of the semi-insulated furnace 210) via a pipe, and the air outlet of the first economizer 600 is connected to the external circulating flue gas inlet 140. It should be noted that the first economizer 600 is installed at the tail of the boiler body 200. The boiler body 200 is suitable for oxidizing the mixed gas containing fuel gas at high temperature to form flue gas, which is then transported to the interior of the first economizer 600. The first economizer 600 is a heat exchange device that can utilize the heat of the flue gas for other processes.

[0074] like Figure 1 As shown, the inlet of the first economizer 600 is suitable for introducing softened water, and the outlet of the first economizer 600 is connected to the inlet of the upper boiler drum 300 for injecting the heat-exchanged hot water into the upper boiler drum 300; the steam outlet 307 of the upper boiler drum 300 is suitable for releasing steam. It should be noted that the flue gas entering the first economizer 600 and the softened water entering the first economizer 600 exchange heat inside the first economizer 600; during heat exchange, the flue gas transfers heat to the softened water, and the softened water absorbs a large amount of heat energy before entering the upper boiler drum 300. After heat exchange, the flue gas re-enters the gas pipeline 100 of the flameless gas-fired boiler through the external circulation pipe 700, providing heat energy for the high-temperature oxidation operation of the semi-insulated furnace 210; while the upper boiler drum 300 is used for steam-water separation, transporting the saturated steam generated by the high-temperature softened water to the outside. This application effectively utilizes the flue gas generated by the flameless gas-fired boiler for new production operations.

[0075] A thermometer 660 is provided at the outlet of the first energy-saving device 600 to detect the temperature of the flue gas released from the first energy-saving device 600.

[0076] In one possible implementation, it further includes: a softened water inlet pipe 610 and a softened water outlet pipe 620, one end of the softened water inlet pipe 610 being adapted to connect to a softened water pump for receiving softened water, and the other end of the softened water inlet pipe 610 being connected to the inlet of the first energy-saving device 600; furthermore, as... Figure 3As shown, the softened water inlet pipe 610 is equipped with a thermometer 614, a softened water control valve 612, and a third shut-off valve 611. The softened water control valve 612 adjusts the flow rate of the softened water in the softened water inlet pipe 610 according to the water volume in the upper boiler drum 300. The thermometer 614 is used to detect the temperature of the softened water before heat exchange, and the third shut-off valve 613 is used to control the on / off state of the softened water inlet pipe 610. One end of the softened water outlet pipe 620 is connected to the outlet of the first energy-saving device 600, and the other end of the softened water outlet pipe 620 is connected to the inlet of the upper boiler drum 300. Furthermore, the softened water outlet pipe 620 is equipped with a fourth shut-off valve 621, which is used to control the on / off state of the softened water outlet pipe 620. The softened water outlet pipe 620 is equipped with a thermometer 640, which is used to detect the water temperature after heat exchange in the softened water outlet pipe 620. A shut-off valve 615 is installed on the straight pipe between the softened water outlet pipe 620 and the softened water inlet pipe 610.

[0077] In one possible implementation, it further includes: a steam pipe 810, one end of which is connected to the steam outlet of the upper boiler drum 300. The steam pipe 810 is equipped with a fourth gas flow meter 812 and a fifth shut-off valve 811. The fourth gas flow meter 812 is used to measure the flow rate of saturated steam in the steam pipe 810, and the fifth shut-off valve 811 is used to control the flow of saturated steam in the steam pipe 810.

[0078] In one possible implementation, such as Figure 1 As shown, it also includes: a second economizer 630. The outlet of the first economizer 600 is connected to the inlet of the second economizer 630 to deliver flue gas to the second economizer 630. The inlet of the second economizer 630 is connected to boiler feedwater (generally from a water treatment plant, return water system, or steam turbine). The outlet of the second economizer 630 is connected to a deaerator. The boiler feedwater is heated by the flue gas and then delivered to the deaerator to increase the inlet temperature of the deaerator and reduce the steam consumption of the deaerator. The outlet of the second economizer 630 is connected to the medium inlet of the air preheater 800 through a pipeline to deliver flue gas to the air preheater 800. The medium outlet of the air preheater 800 is connected to the external circulation pipeline 700. The flue gas released from the boiler body 200 first enters the first economizer 600 for utilization, the flue gas released from the first economizer 600 enters the second economizer 630 for utilization, the flue gas released from the second economizer 630 enters the air preheater 800 for utilization, and finally a portion of the flue gas is transported to the external circulation pipe 700 and sent back to the gas pipeline 100 from the external circulation pipe 700.

[0079] A thermometer 650 is provided at the outlet of the second energy-saving device 630 to detect the temperature of the flue gas released from the second energy-saving device 630.

[0080] In one possible implementation, such as Figure 3As shown, a fourth pressure gauge 941, a gas analyzer 942, and a second fan 940 are installed on the pipe between the outlet of the second energy-saving device 630 and the air preheater 800; and the fourth pressure gauge 941, the gas analyzer 942, and the second fan 940 are arranged sequentially along the flow direction of the flue gas in the pipe; wherein the fourth pressure gauge 941 is suitable for detecting the gas pressure in the pipe. The gas analyzer 942 is a multi-channel gas analyzer, suitable for analyzing the composition of the gases contained in the flue gas and measuring the concentration of carbon monoxide, nitrogen oxides, and methane; the second fan 940 is suitable for conveying the flue gas from the second energy-saving device 630 to the air preheater 800.

[0081] In one possible implementation, the system further includes: a filter 920 and a blower 910; the outlet of the filter 920 is connected to one end of the blower 910 via a pipe, and the other end of the blower 910 is connected to the combustion air inlet of the air preheater 800 via a pipe; the combustion air outlet of the air preheater 800 is connected to the air pipe 900, the auxiliary air pipe 930, and the secondary air intake pipe 950; the combustion air enters the air preheater 800 under the drive of the blower 910; the flue gas in the air preheater 800 heats the combustion air through heat exchange; the preheated combustion air enters the gas pipe 100 through the air pipe 900, enters the auxiliary gas pipe 112 through the auxiliary air pipe 930, and enters the flameout guide pipe 190 through the secondary air intake pipe 950; the filter 920 is suitable for filtering and removing impurities from the combustion air to prevent impurities from entering the pipes. In summary, the air preheater 800 utilizes the temperature of the flue gas released from the boiler body 200 to preheat the combustion air entering the boiler body 200, simplifying the equipment structure while effectively utilizing the residual heat of the flue gas.

[0082] Furthermore, such as Figure 9 As shown, the boiler body 200 also includes: a front heat dissipation shell 530, a rear heat dissipation shell 500 and an isolation layer 510; the isolation layer 510 is disposed between the front heat dissipation shell 530 and the rear heat dissipation shell 500, thereby separating the interior of the front heat dissipation shell 530 and the interior of the rear heat dissipation shell 500 into two separate spaces.

[0083] Furthermore, the semi-insulated furnace 210 is located inside the cavity of the front heat dissipation shell 530, and the end face of the front heat dissipation shell 530 is also trapezoidal. The material of the front heat dissipation shell 530 is a membrane water-cooled wall, and a water flow channel is provided inside it. Water circulates in the front heat dissipation shell 530 to cool it down and prevent the heat of the semi-insulated furnace 210 from being transferred to the outside.

[0084] In one possible implementation, such as Figure 9As shown, the boiler body 200 also includes: a lower header 280 and an upper header 270. The lower header 280 is connected to the inlet of the water flow channel of the front heat dissipation shell 530 and is also connected to the lower drum 400. The upper header 270 is connected to the outlet of the water flow channel of the front heat dissipation shell 530 and is also connected to the upper drum 300. Water in the lower header 280 flows into the water flow channel of the front heat dissipation shell 530 to carry away the heat of the front heat dissipation shell 530 and finally flows from the upper header 270 into the upper drum 300. The water in the upper drum 300 then enters the lower drum 400 through the convection pipe 520 under the gravity of the boiler body, forming a natural circulation power based on the height difference and density difference to form a coolant circulation. Figure 6 As shown, the upper header 270 is provided with a drain outlet 255, and the lower header 280 is provided with a drain outlet 256, which are used to periodically discharge impurities and dirt from the boiler water.

[0085] In one possible implementation, the boiler body 200 further includes an upper drum 300 and a lower drum 400; the upper drum 300 and the lower drum 400 are disposed inside the cavity of the rear heat dissipation shell 500 and are located at the upper and lower ends of the rear heat dissipation shell 500 respectively; and both ends of the upper drum 300 and the lower drum 400 protrude from the opposite side walls of the rear heat dissipation shell 500; the upper drum 300 and the lower drum 400 are connected by multiple convection pipes 520.

[0086] like Figure 9 As shown, the upper boiler drum 300 is equipped with a steam-water separator 320 and a water inlet pipe 330. The steam-water separator 320 is used to separate liquid to obtain dry steam. The water inlet pipe 330 is connected to the softened water outlet pipe 620 to receive water that has been heat-exchanged by the first energy-saving device 600. Figure 6 As shown, a pressure gauge 303 and a pressure transmitter 304 are installed at the top of the upper boiler drum 300. The sensing ends of the pressure gauge 303 and the pressure transmitter 304 are located inside the upper boiler drum 300, allowing for on-site display of the internal pressure of the upper boiler drum 300. The top of the upper boiler drum 300 is equipped with a vent pipe and two relief pipes. A valve 308 is installed on the vent pipe; safety valves 309 and 311 are installed on the two relief pipes, respectively. Figure 4 As shown, a water level gauge interface 301 is provided on the side wall of the upper boiler drum 300. The water level gauge interface 301 is used to connect a water level gauge. The side wall of the upper boiler drum 300 is also provided with a first sewage pipe 302 and a second sewage pipe 254 for discharging sewage.

[0087] In one possible implementation, the rear heat sink 500 has a "Π"-shaped cross-section, with the open end of the "Π"-shaped structure facing the front heat sink 530; as shown Figure 9As shown, the upper and lower sides of the rear heat dissipation shell 500 are covered by the side walls of the upper pot drum 300 and the lower pot drum 400; the material of the rear heat dissipation shell 500 is also a membrane water-cooled wall, and water flow channels are provided inside, so that water can flow inside the rear heat dissipation shell 500 to remove the heat of the rear heat dissipation shell 500.

[0088] like Figure 7 As shown, a gas inlet 213 is provided on the front wall 214 of the boiler body 200. The gas inlet 213 communicates with the interior of the semi-insulated furnace 210 and is also connected to the flameout guide pipe 190, thereby delivering the mixed gas into the interior of the semi-insulated furnace 210. A sight glass 215 is provided on the rear wall of the boiler body 200, allowing operators to observe the combustion status inside the semi-insulated furnace 210.

[0089] In one possible implementation, such as Figure 9 As shown, it also includes an auxiliary spray gun 219. The jet end of the auxiliary spray gun 219 is located inside the cavity of the semi-insulated furnace 210, and is suitable for injecting a mixture of combustion gas and combustion air into the semi-insulated furnace 210. It should be noted that the auxiliary spray gun 219 is used to start up the system and gradually increase the temperature in the initial state. By using a very small amount of gas to heat the semi-insulated furnace 210, the safety risks of operation can be reduced. Furthermore, the auxiliary spray gun 219 is located below the main gas distributor 180. It should be noted that a small amount of gas in the initial stage can increase the overall temperature because the semi-insulated furnace 210 is in a semi-insulated state, and the heat loss is relatively small. Therefore, in the initial state, a small amount of gas is enough to raise the temperature of the high-temperature energy retention device 211 and the semi-insulated furnace 210 to 800°C.

[0090] In one possible implementation, such as Figure 8 As shown, it also includes: a main combustion temperature sensor 216, the detection end of which is located inside the cavity of the semi-insulated furnace 210, and is suitable for detecting the combustion temperature inside the semi-insulated furnace 210.

[0091] In one possible implementation, a flame sensor 217 is also included. The detection end of the flame sensor 217 is located inside the cavity of the semi-insulated furnace 210 and is suitable for detecting whether an open flame is generated inside the semi-insulated furnace 210.

[0092] In one possible implementation, the boiler body 200 further includes a first maintenance platform 240 and a second maintenance platform 230; the first maintenance platform 240 is located above the boiler body 200; and the second maintenance platform 230 is located beside the boiler body 200.

[0093] The first maintenance platform 240 is equipped with a first staircase 241. One end of the first staircase 241 is connected to the first maintenance platform 240, and the other end of the first staircase 241 is in contact with the ground. Workers can climb up to the first maintenance platform 240 through the first staircase 241 to carry out maintenance on the top of the equipment.

[0094] Furthermore, the first maintenance platform 240 is a rectangular plate structure, and the first maintenance platform 240 is surrounded by a fence 242; the first staircase 241 is a folding staircase.

[0095] The second maintenance platform 230 is equipped with a second staircase 231. One end of the second staircase 231 is connected to the second maintenance platform 230, and the other end of the second staircase 231 is in contact with the ground. Workers can climb up the second staircase 231 to the position of the upper boiler drum 300 to carry out maintenance and repair on the upper boiler drum 300.

[0096] Furthermore, the second maintenance platform 230 is a rectangular plate structure, and the second maintenance platform 230 is surrounded by a fence 232; the second staircase 231 is a straight staircase.

[0097] In terms of combustion method, this application differs from traditional premixed combustion structures and methods. In the pretreatment section of this application's premixed combustion, a large amount of externally circulated flue gas is mixed with the combustion air. The oxygen content is controlled before the gas enters the boiler body 200, and any insufficient air is supplemented by secondary air. This prevents safety issues in the premixing section due to backfire in the boiler body 200. Strictly controlling the oxygen content of the mixed gas to below 10% effectively prevents flame propagation and allows for a corresponding increase in gas power.

[0098] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A flameless gas-fired boiler, characterized in that The utility model relates to a gas boiler, comprising: a gas pipeline, a boiler body and a first economizer; the boiler body is internally provided with a semi-insulated furnace; the gas pipeline is provided with a combustion air inlet for introducing combustion air and an external circulating flue gas inlet for introducing flue gas, so that the gas in the gas pipeline mixes with the combustion air and the flue gas introduced into the gas pipeline to form a mixed gas; the gas outlet end of the gas pipeline is in communication with the internal cavity of the semi-insulated furnace and is adapted to send the mixed gas into the internal cavity of the semi-insulated furnace; the semi-insulated furnace is internally provided with a high-temperature energy residence device adapted to perform high-temperature oxidation on the mixed gas flowing through the high-temperature energy residence device; the gas outlet of the semi-insulated furnace is connected with the external circulating flue gas inlet through the first economizer; the gas outlet end of the gas pipeline is provided with a mixer for mixing the gas, the combustion air and the flue gas in the gas pipeline; the gas outlet end of the mixer is connected with the gas inlet end of a gas distributor; a fire-removing guide pipeline is located between the gas distributor and the boiler body and is in communication with the internal cavity of the semi-insulated furnace; the high-temperature energy residence device is formed by stacking heat-resistant materials.

2. The flameless gas boiler according to claim 1, characterized in that, the fire-removing guide pipeline is provided with a secondary air inlet.

3. The flameless gas boiler according to claim 1, characterized in that, The utility model further comprises: an air pipeline and an external circulating pipeline; the combustion air inlet is connected with the air pipeline, and the external circulating flue gas inlet is connected with the external circulating pipeline.

4. The flameless gas boiler according to claim 3, characterized in that, The utility model further comprises: a second economizer; the gas outlet of the first economizer is connected with the gas inlet of the second economizer, and the gas outlet of the second economizer is connected with the external circulating flue gas inlet through the external circulating pipeline.

5. The flameless gas boiler according to claim 4, characterized in that, The utility model further comprises: an air preheater; the air pipeline is provided with the air preheater at the end where the combustion air is injected; the air preheater is adapted to preheat the combustion air.

6. The flameless gas boiler according to claim 5, characterized in that, the gas outlet of the second economizer is connected with the medium inlet of the air preheater through a pipeline, and the medium outlet of the air preheater is connected with the external circulating pipeline.

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