Flameless gas-fired boiler

Abstract

The invention relates to a flameless gas-fired boiler. The flameless gas-fired boiler comprises a gas pipeline, a boiler body and a first energy saver, a semi-adiabatic hearth is arranged in the boiler body; the gas inlet end of the gas pipeline is suitable for introducing gas, and the gas pipeline is provided with a combustion-supporting air inlet suitable for introducing combustion-supporting air and an external circulation flue gas inlet suitable for introducing flue gas; fuel gas in the fuel gas pipeline is mixed with combustion-supporting air and flue gas which are introduced into the fuel gas pipeline to form mixed gas; the gas outlet end of the gas pipeline communicates with an inner cavity of the semi-adiabatic hearth and is suitable for feeding mixed gas into the semi-adiabatic hearth. A high-temperature energy retaining device is arranged in the semi-adiabatic hearth and is suitable for performing high-temperature oxidation on mixed gas flowing through the high-temperature energy retaining device; and a gas outlet of the semi-adiabatic hearth is connected with an external circulation flue gas inlet through a first energy saver. The contact probability of oxygen and nitrogen can be reduced, and generation of nitric oxide is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of combustion boilers, and in particular to a flameless gas boiler. Background Art

[0002] With the transformation of the national energy structure and industrial upgrading, the government is vigorously promoting the use of clean energy such as natural gas. Low nitrogen emissions from gas boilers have become a new requirement of the new era. Ordinary gas boilers produce extremely high levels of nitrogen oxides (NOx) in the exhaust gas during combustion. The NO generated by combustion is easily oxidized into NO2 after being discharged into the atmosphere, which in turn forms acid rain and acid mist, seriously threatening human health. Therefore, it is urgent to carry out nitrogen reduction transformation of gas boilers.

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

[0004] In view of this, the present application proposes a flameless gas boiler.

[0005] According to one aspect of the present application, there is provided a flameless gas boiler comprising: a gas pipeline, a boiler body and a first economizer; A semi-insulated furnace is provided in the boiler body; The gas inlet end of the gas pipeline is suitable for introducing gas, and 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 is mixed with the combustion air and flue gas introduced into the gas pipeline to form a mixed gas; the gas outlet end of the gas pipeline is connected to the inner cavity of the semi-adiabatic furnace and is suitable for delivering the mixed gas into the interior of the semi-adiabatic furnace; A high-temperature energy retention device is provided in the semi-adiabatic furnace, which is suitable for high-temperature oxidation of the mixed gas flowing through the high-temperature energy retention device; The gas outlet of the semi-adiabatic furnace is connected to the external circulating flue gas inlet through the first energy saver.

[0006] In a possible implementation, a mixer is provided at the gas outlet end of the gas pipeline to mix the gas, combustion-supporting air and flue gas in the gas pipeline.

[0007] In a possible implementation, the method further includes: a gas distributor, wherein the gas outlet of the mixer is connected to the gas inlet of the gas distributor.

[0008] In a possible implementation, the system further includes: a de-fire guide pipe, which is located between the gas distributor and the boiler body and communicates with the inner cavity of the semi-insulated furnace.

[0009] In a possible implementation, the de-fire guide duct is provided with a secondary air inlet.

[0010] In a possible implementation, the high-temperature energy retention device is formed by stacking thermal shock resistant materials.

[0011] In a possible implementation, it further includes: an air duct and an external circulation duct; the combustion air inlet is connected to the air duct, and the external circulation flue gas inlet is connected to the external circulation duct.

[0012] In a possible implementation, the device further includes: a second energy saver; The air outlet of the first economizer is connected to the air inlet of the second economizer, and the air outlet of the second economizer is connected to the external circulation flue gas inlet through an external circulation pipeline.

[0013] In a possible implementation, it further includes: an air preheater; an 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.

[0014] In a possible implementation, the air outlet of the second economizer is connected to the medium inlet of the air preheater through a pipeline, and the medium outlet of the air preheater is connected to the external circulation pipeline.

[0015] Beneficial effects: The gas pipeline is suitable for transmitting natural gas and other gases. The combustion-supporting air inlet opened in the gas pipeline is suitable for introducing combustion-supporting air into the gas pipeline from the outside. The external circulation flue gas inlet opened in the gas pipeline is suitable for circulating the flue gas output from the semi-adiabatic furnace back to the gas pipeline. The gas in the gas pipeline is mixed with the combustion-supporting air and flue gas to form a mixed gas, which is transported to the semi-adiabatic furnace for high-temperature oxidation. The split high-temperature energy retention device in the semi-adiabatic furnace is used to achieve flameless combustion of the mixed gas in the semi-adiabatic furnace, which is also called high-temperature oxidation or flameless oxidation. The temperature of the combustion or oxidation of the mixed gas mainly depends on the heat brought by the circulating flue gas. The present application replaces the flame combustion method with a high-temperature oxidation method, and uses a high-temperature environment and a high-temperature energy carrier (a high-temperature energy retention device) instead of an electric spark or an open flame to activate the oxidation reaction chain, so that the gas can be oxidized or burned completely without flame in a high-temperature environment, completely eliminating the outer flame with the highest temperature in the basic structure of the flame, thereby eliminating the reaction motive force of nitrogen oxides; since the exhaust flue gas is circulated into the gas pipeline, a large amount of flue gas is avoided from being discharged into the external environment. At the same time, the flue gas can dilute the oxygen content and gas content in the gas pipeline, which can effectively reduce the contact probability between oxygen and nitrogen, thereby further reducing the generation of nitrogen oxides.

[0016] Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the application and, together with the description, serve to explain the principles of the application.

[0018] Figure 1 A schematic diagram showing the structural connection relationship of the flameless gas boiler according to an embodiment of the present application; Figure 2 Show Figure 1 A partial enlarged view of Figure 3 Show Figure 1 A partial enlarged view of Figure 4 A top view of a boiler body according to an embodiment of the present application is shown; Figure 5 A front view of a boiler body according to an embodiment of the present application is shown; Figure 6 Show Figure 5 A local map of Figure 7 A side view of a boiler body according to an embodiment of the present application is shown; Figure 8 A cross-sectional view showing a boiler body according to an embodiment of the present application; Figure 9 Show Figure 8 A partial diagram of .

[0019] Gas pipeline 100, combustion air inlet 130, external circulation flue gas inlet 140, mixer 150, oxygen concentration detector 151, dry flame arrester 160, thermometer 161, expansion joint 170, de-fired diversion pipeline 190, secondary air inlet 191, gas distributor 180, boiler body 200, semi-insulated furnace 210, high-temperature energy retention device 211, first economizer 600, external circulation pipeline 700, first fan 720, air preheater 800, air pipeline 90 0, auxiliary 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 economizer 630, second fan 940, filter 920, blower 910, front heat dissipation housing 530, rear heat dissipation housing 500, isolation layer 510, lower header 280, upper header 270, upper boiler drum 300, lower boiler drum 400, auxiliary spray gun 219, main combustion temperature sensor 216, flame sensor 217. DETAILED DESCRIPTION

[0020] Various exemplary embodiments, features, and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0021] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0022] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0023] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0024] In addition, numerous specific details are provided in the detailed description below to better illustrate the present application. Those skilled in the art will appreciate that the present application can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0025] Figure 1 A schematic diagram showing the connection relationship of the flameless gas boiler according to an embodiment of the present application; Figure 2 Show Figure 1 A partial enlarged view of Figure 3 Show Figure 1 A partial enlarged view of Figure 4 A top view of a boiler body according to an embodiment of the present application is shown; Figure 5 A front view of a boiler body according to an embodiment of the present application is shown; Figure 6 Show Figure 5 A local map of Figure 7 A side view of a boiler body according to an embodiment of the present application is shown; Figure 8 A cross-sectional view showing a boiler body according to an embodiment of the present application; Figure 9 Show Figure 8 A local graph of . Figure 1 As shown, the flameless gas boiler comprises: a gas pipeline 100, a boiler body 200 and a first energy saver 600; Figure 8As shown, a semi-adiabatic furnace 210 is provided in the boiler body 200; the air inlet end of the gas pipeline 100 is suitable for introducing gas, and the air outlet end of the gas pipeline 100 is connected to the interior of the cavity of the semi-adiabatic furnace 210; the gas pipeline 100 is provided with a combustion air inlet 130 suitable for introducing combustion air and an external circulation flue gas inlet 140 suitable 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; a high-temperature energy retention device 211 is provided in the semi-adiabatic furnace 210, which is suitable for high-temperature oxidation of the mixed gas flowing through the high-temperature energy retention device 211; the air outlet of the semi-adiabatic furnace 210 is connected to the external circulation flue gas inlet 140 through a first energy saver 600.

[0026] Here, it should be noted that the gas pipeline 100 is suitable for transmitting natural gas and other gases, the combustion air inlet 130 opened in the gas pipeline 100 is suitable for introducing combustion air from the outside into the gas pipeline 100, and the external circulation flue gas inlet 140 opened in the gas pipeline 100 is suitable for circulating the flue gas output from the semi-adiabatic furnace 210 back to the gas pipeline 100. The gas in the gas pipeline 100 is mixed with the combustion air and the flue gas to form a mixed gas, which is transported to the semi-adiabatic furnace 210 for high-temperature oxidation; the split high-temperature energy retention device 211 in the semi-adiabatic furnace 210 is used to enable the mixed gas to achieve flameless combustion in the semi-adiabatic furnace 210, which is also called high-temperature oxidation or flameless oxidation. The temperature of the combustion or oxidation of the mixed gas mainly depends on the heat brought by the circulating flue gas. The present application replaces the flame combustion method with a high-temperature oxidation method, and uses a high-temperature environment and a high-temperature energy carrier (a high-temperature energy retention device 211) instead of an electric spark or an open flame to activate the oxidation reaction chain, so that the gas is oxidized or burned completely without flame in a high-temperature environment, completely eliminating the outer flame with the highest temperature in the basic structure of the flame, thereby eliminating the reaction motive force of nitrogen oxides; since the exhaust flue gas is circulated into the gas pipeline 100, a large amount of flue gas is avoided from being discharged into the external environment. At the same time, the flue gas can dilute the oxygen content and gas content in the gas pipeline 100, which can effectively reduce the contact probability between oxygen and nitrogen, thereby further reducing the generation of nitrogen oxides.

[0027] In a possible implementation, a mixer 150 is provided at one end of the gas pipeline 100 connected 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 to mix the gas, combustion air and flue gas in the gas pipeline 100. Figure 1 and Figure 4As shown, the mixer 150 is installed on the gas pipeline 100. The mixer 150 is suitable for fully mixing the flue gas, gas and combustion-supporting air flowing therethrough to achieve the purpose of uniform mixing, so that the flue gas effectively dilutes the oxygen content and gas content in the gas pipeline 100. Preferably, the mixer 150 is a static mixer.

[0028] In a possible implementation, it also includes: a gas distributor 180, the gas outlet end of the mixer 150 is connected to the gas inlet end of the gas distributor 180. It should be noted that if the flow rate of the mixed gas is large and it is directly filled into the semi-adiabatic furnace 210, it is easy for the mixed gas to not be evenly distributed in the semi-adiabatic furnace 210. Therefore, before the mixed gas enters the semi-adiabatic 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 on the entire cross-section, and the mixed gas fully enters the semi-adiabatic furnace 210, thereby improving the uniform distribution of the mixed gas in the semi-adiabatic furnace 210. In summary, by designing a uniform mixed airflow, the combustion temperature field can be evenly distributed throughout the semi-adiabatic furnace 210, and the temperatures at each point of the oxidation reaction tend to be consistent. There is no flame, no local maximum temperature, and no minimum temperature of the cold wall. The wall temperature at any point in the semi-adiabatic furnace 210 is greater than 800°C, avoiding the phenomenon of incomplete combustion of the mixed gas. The carbon monoxide content in the exhaust gas can be greatly reduced to even zero, thereby achieving complete combustion. At the same time, since the burning flame and the maximum temperature of the flame are eliminated, the generation of dynamic nitrogen oxides is effectively suppressed.

[0029] In one possible implementation, Figure 1 and Figure 4 As shown, it also includes: a de-fired flow guide pipe 190, which is located between the gas distributor 180 and the boiler body 200. Figure 4 As shown, one side of gas distributor 180 extends into one end of de-fired flow conduit 190. The other end of de-fired flow conduit 190 is fixed to the front wall 214 of boiler body 200 and communicates with the interior of semi-adiabatic furnace 210. Gas distributor 180 evenly distributes the mixed gas upon entering de-fired flow conduit 190. This increases the transmission length and reduces the risk of flashback in the pre-mixing section, thereby ensuring safety in the pre-mixing section.

[0030] Furthermore, the length of the de-ignition guide pipe 190 is greater than 600 mm. This pipe is used to extend the distance between the gas distributor 180 and the boiler body 200, forming a de-ignition section at least 600 mm long. After the mixed gas passes through the de-ignition guide pipe 190 and enters the semi-adiabatic furnace 210, it undergoes flameless oxidation or combustion under the activation conditions of the high-temperature energy retention device 211 and the high-temperature environment within the semi-adiabatic furnace 210. Preferably, the length of the de-ignition guide pipe 190 ranges from 0.6 to 1.5 meters.

[0031] Furthermore, the de-fire diversion duct 190 is composed of a coaxial sleeve and a refractory layer. One end of the sleeve is welded to the front wall 214 of the boiler body 200. The refractory layer is located on the inner side of the sleeve and is made of a relatively hard refractory material. Due to the high flow rate of the mixed gas in the de-fire diversion duct 190, the inner wall of the channel is provided with a relatively hard refractory layer to prevent gas erosion and damage. Preferably, the refractory layer is made of high-aluminum casting material or a high-aluminum preformed product with a temperature resistance of up to 1200°C.

[0032] Furthermore, a high temperature resistant insulation layer is filled between the refractory layer and the casing. Preferably, the high temperature resistant insulation layer is made of zirconium-containing aluminum silicate products or ceramic fibers, and is also required to have a temperature resistance of up to 1200°C.

[0033] In one possible implementation, Figure 4 As shown, the defire guide duct 190 is provided with a secondary air inlet 191. The secondary air inlet 191 is connected to the defire guide duct 190 and is suitable for introducing combustion-supporting air from the secondary air inlet 191 into the defire guide duct 190; it should be noted that combustion-supporting air is input to the secondary air inlet 191 only when the content of combustion-supporting air in the semi-adiabatic furnace 210 is insufficient, and the supplementary combustion-supporting air enters the defire guide duct 190 from the secondary air inlet 191 and is premixed in the form of secondary air. It should be noted here that the addition of the secondary air inlet 191 in the defire guide channel can not only ensure the safety of the front end, but also ensure the amount of combustion-supporting air required for combustion or even excess, to ensure complete combustion.

[0034] In one possible implementation, it also includes a dry flame arrester 160. The gas outlet end of the mixer 150 is connected to one end of the dry flame arrester 160 through a pipeline. The mixer 150 and the dry flame arrester 160 are arranged in sequence along the flow direction of the mixed gas. The dry flame arrester 160 is a new type of fire prevention equipment that blocks and disperses flames and suppresses fire sources, thereby preventing the gas pipeline 100 from catching fire.

[0035] In one possible implementation, it also includes: an expansion joint 170, which is arranged between the dry flame arrester 160 and the gas distributor 180; further, the expansion joint 170 adopts a detachable expansion joint 170, and the flanges at both ends of the detachable expansion joint 170 are detachably connected to the flange of the dry flame arrester 160 and the flange of the gas distributor 180 respectively; it should be noted that the expansion joint 170 can overcome the offset caused by the different axial directions of the pipeline docking within a certain angle, can facilitate the installation and disassembly of the pipeline, and can be disassembled at any time to clean, maintain and repair the dry flame arrester 160 and the gas distributor 180.

[0036] In summary, the end of the gas pipeline 100 connected to the boiler body 200 is provided with a mixer 150, a dry flame arrester 160, an expansion joint 170, a gas distributor 180 and a defire diversion pipe 190 in sequence; and they are arranged and connected in sequence along the flow direction of the mixed gas.

[0037] Since the mixed gas in the gas pipeline 100 has the characteristics of flame propagation, the high temperature radiation of the semi-adiabatic furnace 210 causes the semi-adiabatic furnace 210 body to be heated and backfire. If the flame returns to the inside of the gas pipeline 100, it is easy to cause detonation and explosion. This is a serious bottleneck in the development history of traditional premixed combustion technology. The application is to set up a fire-proofing diversion pipe 190 to lengthen the distance between the gas pipeline 100 and the semi-adiabatic furnace 210. If the semi-adiabatic furnace 210 catches fire, the flame can be prevented from directly entering the gas pipeline 100; and because a dry flame arrester 160 is set between the gas pipeline 100 and the fire-proofing diversion pipe 190, the flame can be effectively intercepted to prevent the flame from propagating to the inside of the gas pipeline 100 and causing a detonation accident; the safety index and protection performance of the entire equipment during operation are improved, reflecting the advantages of premixed combustion technology.

[0038] In one possible implementation, Figure 2 As shown, an oxygen concentration detector 151 is provided on the pipe between the mixer 150 and the dry flame arrester 160; the detection end of the oxygen concentration detector 151 is located inside the pipe 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 defire diversion pipe 190 through the secondary air inlet 191; when the oxygen content exceeds the standard, the flow rate of the introduced combustion-supporting air is promptly adjusted and reduced to keep the oxygen content in the mixed gas within a safe value (content 10%).

[0039] In one possible implementation, 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 detection end of the thermometer 161 is located inside the pipe, suitable for detecting the temperature of the mixed gas before entering the gas distributor 180 .

[0040] In one possible implementation, Figure 2 As shown, the gas pipeline 100 is provided with a stop valve 103, a first gas regulating valve 110, a first gas flow meter 111 and two first shut-off valves 120; the stop valve 103, the first gas regulating valve 110, the first gas flow meter 111 and the two first shut-off valves 120 are arranged in sequence along the flow direction of the gas 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 circulation flue gas inlet 140. The first gas regulating valve 110 is suitable for controlling the flow of gas in the gas pipeline 100 at any time, and the first gas flow meter 111 is suitable for detecting the flow of gas in the gas pipeline 100; the two first shut-off valves 120 are suitable for controlling the on-off of the gas pipeline 100 and thereby controlling the supply of gas.

[0041] In one possible implementation, Figure 2 As shown, the gas pipeline 100 is also provided 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 respectively detecting the gas pressure and gas temperature in the gas pipeline 100; the second pressure gauge 121 is arranged between the two first shut-off valves 120.

[0042] In one possible implementation, the gas pipeline 100 is further provided with a discharge pipeline 123 , on which a safety valve 122 is provided for regulating the on-off state of the discharge pipeline 123 . The discharge pipeline 123 is suitable for timely draining the gas in the gas pipeline 100 under special circumstances.

[0043] In one possible implementation, the system further includes: an air duct 900, one end of which is connected to the combustion air inlet 130 and adapted to supply combustion air into the gas pipeline 100; and a first oxygen regulating valve 901 provided on the air duct 900, adapted to regulate the flow of the combustion air in the air duct 900. When the oxygen content exceeds a standard, the first oxygen regulating valve 901 is promptly adjusted to reduce the amount of combustion air entering the gas pipeline 100, thereby lowering the oxygen content in the mixed gas. In summary, the first oxygen regulating valve 901 strictly controls the oxygen content in the mixed gas to no more than 10%.

[0044] Further, such as Figure 1 As shown, an air preheater 800 is installed at the end of air duct 900 where combustion air is injected. It should be noted that air preheater 800 is one of the energy-saving devices of this application. Preheating combustion air can save energy and play a very important role in improving thermal efficiency. Furthermore, preheating combustion air is more suitable for low-calorific value gas. The specific preheating temperature can be determined according to needs. Generally, for low-calorific value or difficult-to-burn gas, the preheating temperature can be increased as needed to ensure normal combustion.

[0045] 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-adiabatic furnace 210, and the other end of which is connected to the 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, suitable for regulating the flow rate of the flue gas in 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°C; the flow rate of the flue gas in the external circulation pipe 700 is adjusted according to the combustion temperature in the semi-adiabatic furnace 210, and further, the flow rate of the flue gas in the external circulation pipe 700 is adjusted based on the combustion temperature in the semi-adiabatic furnace 210, and further, the combustion temperature in the semi-adiabatic furnace 210 is not greater than 1100°C as a criterion for adjusting the flow rate of the flue gas in the external circulation pipe 700.

[0046] The outer circulation pipeline 700 is provided with a first fan 720 , which is suitable for providing power for the flow of the flue gas so that the flue gas is smoothly delivered into the gas pipeline 100 .

[0047] In one possible implementation, Figure 4 As shown, the high-temperature energy retention device 211 is a masonry formed by thermal shock resistant materials. Furthermore, the thermal shock resistant materials can be high-alumina bricks, alumina bricks, silicon carbide bricks and other materials with excellent thermal shock resistance and high refractoriness. Preferably, the high-temperature energy retention device 211 is a masonry formed by multiple high-alumina bricks, and the masonry is a rectangular structure.

[0048] In one possible implementation, the ratio of the volume of the high-temperature energy retention device 211 to the total volume of the semi-adiabatic 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 quality of the fuel gas. Generally, the volume of the high-temperature energy retention device 211 is smaller for fuel gas with a high calorific value, and increases as the calorific value decreases.

[0049] In one possible implementation, Figure 8As shown, the main body of the semi-adiabatic furnace 210 is cylindrical, with trapezoidal end faces. The furnace wall 260 of the semi-adiabatic furnace 210 is constructed of high-aluminum refractory material. The furnace wall 260 isolates the front heat dissipation housing 530 of the boiler body 200 and prevents heat transfer, preventing the membrane-type water-cooled wall from absorbing heat from the semi-adiabatic furnace 210. During normal operation, the temperature of the semi-adiabatic furnace 210 (the temperature within the combustion chamber) is controlled above 800°C, ensuring that the entire semi-adiabatic furnace 210, including the furnace wall 260, remains above 800°C. The temperature of oxidation or flameless combustion is controlled within 1100°C, eliminating the cold wall effect and preventing the interruption of the reaction chain and incomplete combustion caused by the cold wall effect. To reduce nitrogen oxide emissions to zero, the combustion temperature can be controlled within 1000°C.

[0050] In one possible implementation, Figure 2 As shown, the boiler body 200 is provided with an auxiliary air inlet 201 for connecting to the auxiliary gas pipeline 112 , and the auxiliary air inlet 201 is communicated with the interior of the semi-adiabatic furnace 210 , and is suitable for injecting gas into the semi-adiabatic furnace 210 through the auxiliary air inlet 201 .

[0051] In one possible implementation, Figure 2 As shown, it also includes: an auxiliary gas pipeline 112, one end of which is suitable for injecting gas, and the other end of the auxiliary gas pipeline 112 is connected to the auxiliary air inlet 201 of the semi-adiabatic furnace 210; the auxiliary gas pipeline 112 is also provided with a combustion air inlet and an external circulation flue gas inlet, and its combustion air inlet is connected to the auxiliary air pipeline 930 to receive combustion air, and its external circulation flue gas inlet is connected to the external circulation pipeline 700 to receive flue gas.

[0052] The secondary air duct 930 is provided with a second oxygen regulating valve 931 , which is adapted to regulate the air flow in the secondary air duct 930 .

[0053] 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 circulation flue gas inlet. The second mixer 115 is suitable for mixing the combustion air, flue gas and fuel gas in the auxiliary gas pipeline 112 to improve the uniformity of the mixed gas entering the semi-adiabatic furnace 210.

[0054] In a possible implementation, a gas distributor is also provided at one end of the secondary gas pipeline 112 connected to the secondary gas inlet 201 to improve the uniformity of gas entering the semi-adiabatic furnace 210 .

[0055] In one possible implementation, the secondary gas pipeline 112 is equipped with a shutoff valve 152, a second gas flowmeter 113, a third pressure gauge 154, and two second shutoff valves 114. These valves are arranged sequentially along the flow direction of gas within the secondary gas pipeline 112, with the second shutoff valves 114 located at the front end of the combustion air inlet and the externally recycled flue gas inlet. The second gas flowmeter 113 is used to detect the flow of gas within the secondary gas pipeline 112. The shutoff valve 152 and the two second shutoff valves 114 are used to control the flow of gas within the secondary gas pipeline 112.

[0056] In one possible implementation, the auxiliary gas pipeline 112 is also provided with a discharge pipeline 155, and a safety valve 156 is provided on the discharge pipeline 155 for regulating the on-off of the discharge pipeline 155. The discharge pipeline 155 is suitable for timely emptying the gas in the auxiliary gas pipeline 112 under special circumstances.

[0057] It should be noted that this application utilizes two gas pipelines: a main gas pipeline 100 (connecting to the main distributor) and a secondary gas pipeline 112 (connecting to the secondary distributor). Initially, secondary gas pipeline 112 provides a high-temperature mixed gas to the semi-adiabatic furnace 210 for combustion or oxidation, raising the temperature of the semi-adiabatic furnace 210 to a certain value. After this, secondary gas pipeline 112 is shut down (or allowed to continue operating), and the main gas pipeline 100 is reintroduced as the primary heat source for energy output. This design reduces the safety risk of the boiler body 200 (the probability of flameout due to uncontrollable factors) to zero.

[0058] Furthermore, the gas inlet end of the auxiliary gas pipeline 112 is connected to the main gas pipeline 100 , and a third gas flow meter 116 is provided at the gas inlet end of the main gas pipeline 100 .

[0059] In one possible implementation, Figure 1 As shown, it also includes: a secondary air intake duct 950, one end of which is suitable for introducing combustion-supporting air, and the other end of the secondary air intake duct 950 is connected to the secondary air inlet 191 of the defire guide duct 190; and a third oxygen regulating valve 951 is provided on the secondary air intake duct 950, which is suitable for adjusting the flow rate of the combustion-supporting air in the secondary air intake duct 950, so that when the content of the combustion-supporting air in the semi-adiabatic furnace 210 is insufficient, the secondary air intake duct 950 is supplemented with combustion-supporting air; the air inlet end of the secondary air intake duct 950 and the air inlet end of the auxiliary air duct 930 are both connected to the air duct 900, so that they can both be connected to the combustion-supporting air preheated by the air preheater 800.

[0060] 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-adiabatic furnace 210) through a pipeline, and the air outlet of the first economizer 600 is connected to the external circulating flue gas inlet 140; here, it should be noted that the first economizer 600 is installed at the tail of the boiler body 200, and the boiler body 200 is suitable for high-temperature oxidation of the mixed gas containing fuel gas to form flue gas and then transporting it to the inside of the first economizer 600. The first economizer 600 is a heat exchange device that can use the heat of the flue gas to perform work in other sections.

[0061] like Figure 1 As shown, the water inlet of the first economizer 600 is suitable for introducing softened water. The water outlet of the first economizer 600 is connected to the water inlet of the upper drum 300 and is suitable for injecting hot water after heat exchange into the upper drum 300. The steam outlet 307 of the upper 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 within the first economizer 600. During the heat exchange, the flue gas transfers heat to the softened water, which absorbs a large amount of heat energy and then enters the upper drum 300. After the heat exchange, the flue gas re-enters the gas pipeline 100 of the flameless gas-fired boiler through the external circulation pipeline 700, providing heat energy for the high-temperature oxidation process in the semi-adiabatic furnace 210. The upper drum 300 is used to separate steam and water, and transmits 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 processes.

[0062] A thermometer 660 is provided at the gas outlet of the first economizer 600 for detecting the temperature of the flue gas released from the first economizer 600 .

[0063] In a 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 is suitable for connecting to a softened water pump to receive softened water, and the other end of the softened water inlet pipe 610 is connected to the water inlet of the first energy saver 600; further, 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 softened water in the softened water inlet pipe 610 based on the amount of water in the upper 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 of the softened water inlet pipe 610. The softened water outlet pipe 620 has one end connected to the water outlet of the first economizer 600, and the other end connected to the water inlet of the upper 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 of the softened water outlet pipe 620. The softened water outlet pipe 620 is also equipped with a thermometer 640, which is used to detect the temperature of the water in the softened water outlet pipe 620 after heat exchange. A shut-off valve 615 is provided on the straight pipe between the softened water outlet pipe 620 and the softened water inlet pipe 610 .

[0064] In one possible implementation, it also includes: a steam pipe 810, one end of the steam pipe 810 is connected to the air outlet of the upper boiler drum 300, and the steam pipe 810 is provided 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 of saturated steam in the steam pipe 810, and the fifth shut-off valve 811 is suitable for controlling the flow of saturated steam in the steam pipe 810.

[0065] In one possible implementation, Figure 1 As shown, the system also includes a second economizer 630. The air outlet of the first economizer 600 is connected to the air inlet of the second economizer 630 to transport the flue gas to the second economizer 630. The water inlet of the second economizer 630 is connected to the boiler feed water (typically from a water treatment station, return water system, or steam turbine). The water outlet of the second economizer 630 is connected to the deaerator. The boiler feed water is heated by heat exchange with the flue gas and then transported to the deaerator to increase the deaerator's inlet temperature and reduce the deaerator's steam consumption. The air outlet of the second economizer 630 is connected to the medium inlet of the air preheater 800 via a pipe to transport the flue gas to the air preheater 800. The medium outlet of the air preheater 800 is connected to the external circulation pipe 700. The flue gas released by the boiler body 200 first enters the first energy saver 600 for utilization, the flue gas released by the first energy saver 600 enters the second energy saver 630 for utilization, and the flue gas released by the second energy saver 630 enters the air preheater 800 for utilization. Finally, part 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.

[0066] A thermometer 650 is provided at the gas outlet of the second economizer 630 for detecting the temperature of the flue gas released from the second economizer 630 .

[0067] In one possible implementation, Figure 3As shown, the pipeline between the outlet of the second economizer 630 and the air preheater 800 is equipped with a fourth pressure gauge 941, a gas analyzer 942, and a second fan 940. These four pressure gauges 941, gas analyzer 942, and second fan 940 are arranged sequentially along the flow direction of the flue gas within the pipeline. The fourth pressure gauge 941 is used to detect the gas pressure within the pipeline. The gas analyzer 942 is a multi-channel gas analyzer suitable for analyzing the gas composition of the flue gas and measuring the concentrations of carbon monoxide, nitrogen oxides, and methane. The second fan 940 is used to transport the flue gas from the second economizer 630 to the air preheater 800.

[0068] In one possible implementation, it also includes: a filter 920 and a blower 910; the air outlet end of the filter 920 is connected to one end of the blower 910 through a pipe, and the other end of the blower 910 is connected to the combustion air inlet of the air preheater 800 through a pipe, and the combustion air outlet of the air preheater 800 is connected to the air duct 900, the auxiliary air duct 930, and the secondary air intake duct 950. The combustion air enters the air preheater 800 driven by the blower 910, and the flue gas in the air preheater 800 heats the combustion air by heat exchange. The preheated combustion air enters the gas pipeline 100 through the air duct 900, enters the auxiliary gas pipeline 112 through the auxiliary air duct 930, and enters the defire diversion pipeline 190 through the secondary air intake pipeline 950. The filter 920 is suitable for filtering and removing impurities from the combustion air to prevent impurities from entering the pipeline. In summary, the air preheater 800 utilizes the temperature of the flue gas released by the boiler body 200 to preheat the combustion air to be introduced into the boiler body 200, thereby simplifying the equipment structure and effectively utilizing the residual heat of the flue gas.

[0069] Further, such as Figure 9 As shown, the boiler body 200 further includes: a front heat dissipation shell 530, a rear heat dissipation shell 500 and an isolation layer 510; the isolation layer 510 is arranged 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.

[0070] Furthermore, the semi-insulated furnace 210 is arranged 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. The water circulates in the front heat dissipation shell 530, which is suitable for cooling the front heat dissipation shell 530 and avoiding the heat of the semi-insulated furnace 210 from being transferred to the outside.

[0071] In one possible implementation, Figure 9As shown, the boiler body 200 further 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. The water in the lower header 280 flows into the water flow channel of the front heat dissipation shell 530 to take away the heat of the front heat dissipation shell 530 and eventually flows from the upper header 270 to the upper drum 300. The water in the upper drum 300 then relies on the gravity of the boiler body to enter the lower drum 400 through the convection pipe 520, and relies on the height difference and density difference to form a natural circulation power to form a coolant circulation. Figure 6 As shown, the upper header 270 is provided with a sewage outlet 255, and the lower header 280 is provided with a sewage outlet 256, which are used to regularly discharge impurities and dirt in the boiler water.

[0072] In one possible implementation, the boiler body 200 also includes an upper boiler drum 300 and a lower boiler drum 400; the upper boiler drum 300 and the lower boiler drum 400 are arranged inside the cavity of the rear heat dissipation shell 500 and are respectively located at the upper and lower ends of the rear heat dissipation shell 500; and both ends of the upper boiler drum 300 and the lower boiler drum 400 protrude from the opposite side walls of the rear heat dissipation shell 500; the upper boiler drum 300 and the lower boiler drum 400 are connected through multiple convection tubes 520.

[0073] like Figure 9 As shown, the interior of the upper drum 300 is provided with a steam-water separator 320 and a water inlet pipe 330. The steam-water separator 320 is used to separate the liquid to obtain dry steam. The water inlet pipe 330 is connected to the softened water outlet pipe 620 to receive the water after heat exchange by the first economizer 600. Figure 6 As shown, a pressure gauge 303 and a pressure transmitter 304 are provided on the top of the upper drum 300. The detection ends of the pressure gauge 303 and the pressure transmitter 304 are both located inside the upper drum 300, and can display the internal pressure of the upper drum 300 on site. A vent pipe and two discharge pipes are provided on the top of the upper drum 300. A valve 308 is provided on the vent pipe. A safety valve 309 and a safety valve 311 are provided on the two discharge pipes. Figure 4 As shown, a water level gauge interface 301 is provided on the side wall of the upper drum 300, and the water level gauge interface 301 is used to connect the water level gauge. A first sewage pipe 302 and a second sewage pipe 254 are also provided on the side wall of the upper drum 300 for discharging sewage.

[0074] In a possible implementation, the cross section of the rear heat dissipation housing 500 is a "Π"-shaped structure, and the open end of the "Π"-shaped structure faces the front heat dissipation housing 530; Figure 9As shown, the upper and lower sides of the rear heat dissipation shell 500 cover the side walls of the upper boiler drum 300 and the lower boiler drum 400; the material of the rear heat dissipation shell 500 is also a membrane water-cooled wall, which has a water flow channel inside. Water can flow in the rear heat dissipation shell 500 to take away the heat of the rear heat dissipation shell 500.

[0075] 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-adiabatic furnace 210 and is also connected to the de-fired flow guide duct 190, thereby delivering the mixed gas into the semi-adiabatic furnace 210. A sight glass 215 is provided on the rear wall of the boiler body 200, through which a worker can observe the combustion conditions in the semi-adiabatic furnace 210.

[0076] In one possible implementation, Figure 9 As shown, it also includes: an auxiliary lance 219, the jet end of the auxiliary lance 219 is located inside the cavity of the semi-adiabatic furnace 210, and is suitable for spraying a mixture of fuel gas and combustion-supporting air into the semi-adiabatic furnace 210; it should be noted that the auxiliary lance 219 is used to start the system and gradually increase the temperature in the initial state, and to increase the temperature of the semi-adiabatic furnace 210 with very little fuel gas, which can reduce the safety risk of operation. Furthermore, the auxiliary lance 219 is located below the main gas distributor 180. It should be noted that a small amount of fuel gas in the initial stage can increase the overall temperature, because the semi-adiabatic furnace 210 is in a semi-adiabatic state, and the relative heat loss is relatively small; therefore, in the initial state, a small amount of fuel gas can increase the temperature of the high-temperature energy retention device 211 and the semi-adiabatic furnace 210 to 800°C.

[0077] In one possible implementation, Figure 8 As shown, it also includes: a main combustion temperature sensor 216, the detection end of the main combustion temperature sensor 216 is located inside the cavity of the semi-adiabatic furnace 210, and is suitable for detecting the combustion temperature in the semi-adiabatic furnace 210.

[0078] In a possible implementation, it further includes: a flame sensor 217 , 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 there is an open flame in the semi-insulated furnace 210 .

[0079] In a 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 disposed beside the boiler body 200 .

[0080] The first maintenance platform 240 is provided 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 contacts the ground. Workers can climb onto the first maintenance platform 240 through the first staircase 241 to inspect and maintain the top of the equipment.

[0081] Furthermore, the first maintenance platform 240 is a rectangular plate-shaped structure, and a fence 242 is provided around the first maintenance platform 240; the first staircase 241 is a folding ladder.

[0082] The second maintenance platform 230 is provided 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; the staff can climb to the position of the upper boiler drum 300 through the second staircase 231 to inspect and maintain the upper boiler drum 300.

[0083] Furthermore, the second maintenance platform 230 is a rectangular plate-shaped structure, and a fence 232 is provided around the second maintenance platform 230; the second staircase 231 is a straight staircase.

[0084] In terms of combustion method, this application differs from the traditional premixed combustion structure and method. The pretreatment stage of this application premixes combustion-supporting air while also mixing in a large amount of externally recycled flue gas. The oxygen content of this premixed gas is controlled before it enters the boiler body 200. The insufficient air is supplemented by secondary air, preventing safety issues in the premixing stage caused by flashback of the boiler body 200. Strictly controlling the oxygen content of the mixed gas to less than 10% effectively prevents flame propagation and increases the power of the gas.

[0085] The embodiments of the present application have been described above. The above description is illustrative and not exhaustive, and is not 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 selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A flameless gas boiler, characterized in that: include: Gas pipeline, boiler body and first economizer; A semi-insulated furnace is provided in the boiler body; The gas inlet end of the gas pipeline is suitable for introducing gas, and 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 a mixed gas; the gas outlet end of the gas pipeline is connected to the inner cavity of the semi-adiabatic furnace and is suitable for delivering the mixed gas into the interior of the semi-adiabatic furnace; A high-temperature energy retention device is provided in the semi-adiabatic furnace, which is suitable for high-temperature oxidation of the mixed gas flowing through the high-temperature energy retention device; The air outlet of the semi-adiabatic furnace is connected to the external circulating flue gas inlet through the first economizer.

2. The flameless gas boiler according to claim 1, characterized in that: A mixer is provided at the gas outlet end of the gas pipeline to mix the gas, the combustion-supporting air and the flue gas in the gas pipeline.

3. The flameless gas boiler according to claim 2, characterized in that: Also includes: A gas distributor, wherein the gas outlet end of the mixer is connected to the gas inlet end of the gas distributor.

4. The flameless gas boiler according to claim 3, characterized in that: Also includes: A de-fire guide pipe is located between the gas distributor and the boiler body and is communicated with the inner cavity of the semi-insulated furnace.

5. The flameless gas boiler according to claim 4, characterized in that: The fire-removing guide duct is provided with a secondary air inlet.

6. The flameless gas boiler according to claim 1, characterized in that: The high-temperature energy retention device is formed by stacking thermal shock resistant materials.

7. The flameless gas boiler according to claim 1, characterized in that: Also includes: Air duct and external circulation duct; the combustion-supporting air inlet is connected to the air duct, and the external circulation flue gas inlet is connected to the external circulation duct.

8. The flameless gas boiler according to claim 7, characterized in that: Also includes: Second energy saver; The air outlet of the first economizer is connected to the air inlet of the second economizer, and the air outlet of the second economizer is connected to the external circulation flue gas inlet through the external circulation pipeline.

9. The flameless gas boiler according to claim 8, characterized in that: Also includes: 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.

10. The flameless gas boiler according to claim 8, characterized in that: The air outlet of the second economizer is connected to the medium inlet of the air preheater through a pipeline, and the medium outlet of the air preheater is connected to the external circulation pipeline.

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