Mixed gas combustion system for paper machine

Abstract

The utility model relates to a mixed gas combustion system for a paper machine. The mixed gas combustion system comprises at least one combustor; the combustion-supporting air conveying pipeline is connected with the combustor; the combustion-supporting air fan conveys combustion-supporting air into the combustor through the combustion-supporting air conveying pipeline, and the gas source conveys combustible gas into the combustor through the gas conveying pipeline. Each combustion-supporting air conveying branch, connected to the combustor, of the combustion-supporting air conveying pipeline is provided with a combustion-supporting air control valve used for independently adjusting the air inlet amount of combustion-supporting air flowing through the combustion-supporting air conveying branch. And each fuel gas conveying branch, connected to the combustor, of the fuel gas conveying pipeline is provided with a fuel gas control valve for independently adjusting the gas inflow of combustible gas flowing through the fuel gas conveying branch. According to the combustion system, on one hand, the expected air-fuel ratio can be obtained to improve the combustion efficiency of the system; on the other hand, consumption of natural gas can be effectively saved, and the purposes of energy conservation and environmental protection are achieved.

Description

Technical Field

[0001] The utility model relates to a mixed gas combustion system for a papermaking machine, and more specifically to a combustion system used in the papermaking field for mixing and burning combustion-supporting air and combustible gas. Background Art

[0002] The papermaking industry usually uses a combustion system mainly composed of a burner, a combustion air delivery pipeline, a gas delivery pipeline and a control valve. The combustion air (usually air) is delivered to the burner through the combustion air delivery pipeline, and the combustible gas (usually natural gas) is delivered to the burner through the gas delivery pipeline. The combustion air and the combustible gas are mixed and ignited in the burner cavity, thereby achieving the purpose of full combustion.

[0003] Figure 1 FIG. 1 shows a mixed gas combustion system 100 in the prior art. Figure 1 As shown, the mixed gas combustion system 100 includes at least one burner 6 and 7, a combustion-supporting air delivery pipeline 3 and a gas delivery pipeline 8, wherein the combustion-supporting air blower 1 delivers the combustion-supporting air, preferably air, to at least one burner 6 and 7 via the combustion-supporting air delivery pipeline 3, and the natural gas source S delivers the combustible gas, preferably natural gas, to at least one burner 6 and 7 via the gas delivery pipeline 8. The first burner 6 and the second burner 7 are connected in series with each other to form a combustion unit. The combustion-supporting air delivery pipeline 3 branches out a first combustion-supporting air delivery branch 3a and a second combustion-supporting air delivery branch 3b, and the first combustion-supporting air delivery branch 3a and the second combustion-supporting air delivery branch 3b are respectively connected in parallel to the first burner 6 and the second burner 7. The gas delivery pipeline 8 branches out a first gas delivery branch 8a and a second gas delivery branch 8b, and the first gas delivery branch 8a and the second gas delivery branch 8b are respectively connected in parallel to the first burner 6 and the second burner 7.

[0004] The first combustion-supporting air delivery branch 3a and the first fuel gas delivery branch 8a are jointly equipped with a first linkage valve 4 for the first burner 6, which simultaneously controls the intake amount of the combustion-supporting air flowing through the first combustion-supporting air delivery branch 3a and the intake amount of the combustible gas flowing through the first fuel gas delivery branch 8a.

[0005] The second combustion-supporting air delivery branch 3b and the second gas delivery branch 8b are jointly equipped with a second interlocking valve 5 for the second burner 7, which simultaneously controls the intake amount of the combustion-supporting air flowing through the second combustion-supporting air delivery branch 3b and the intake amount of the combustible gas flowing through the second gas delivery branch 8b.

[0006] It can be seen that in the art, a combustion air-combustible gas linkage valve is usually used to control the mixing ratio of the combustion air and the combustible gas. The reason for using a single linkage valve to simultaneously control the delivery amount of the combustion air and the combustible gas is that the use of a single linkage valve is lower in cost and relatively simpler to control.

[0007] For energy conservation and environmental protection, the combustion system needs to be equipped with a recovery device that recovers and reuses heat from the hot air after the combustion air and combustible gas are mixed and burned. The recovery device is currently generally installed at the front end of the combustion air. When the recovery function is not in use, the recovery device is in a cold state (i.e., a state that is not suitable for circulating waste hot gas); when the recovery function is in use, the recovery device is in a hot state (i.e., a state that is suitable for circulating waste hot gas). Regardless of whether the recovery device is in a cold or hot state, the combustion system needs to correspond to different air-fuel ratios.

[0008] However, the existing linkage valve controls both the combustion air delivery pipeline and the gas delivery pipeline at the same time, so it cannot meet the air-fuel ratio under different working conditions. Moreover, the existing combustion air valve group and fan cannot meet the requirements of the hot state, and there is a risk of deformation and damage of the fire protection tube due to uneven heating of the fire protection tube, which also causes a lot of energy waste.

[0009] Moreover, in the above-mentioned mixed gas combustion system 100, since the heat recovery air valve 9 is in a normally closed state, it cannot be put into use when the combustion system is in operation, so the purpose of heat energy recovery cannot be achieved.

[0010] Some new technical solutions have been developed in this field in an attempt to solve the above technical problems.

[0011] For example, in the utility model patent CN219976419U filed by Ningxia Eastern Thermal Power Co., Ltd. on May 10, 2023, a natural gas burner is disclosed. The natural gas burner includes a fan, an air duct is connected to the outside of the fan, one end of the air duct is connected to the combustion chamber through a fixed plate, a gas pipe is arranged on the top of the combustion chamber, and two branch pipes are connected to the bottom of the gas pipe. A linkage valve group is installed at the connection between the gas pipe and the two branch pipes, one end of the air duct extends into the interior of the combustion chamber and is connected to an air guide plate, one end of the two branch pipes extends into the interior of the combustion chamber and is connected to a dispersion hood, and an inner concave sphere is installed at the inner center of the dispersion hood, the air duct is located on one side of the combustion chamber, and the ends of the two branch pipes are respectively located at the front and rear positions of the combustion chamber, and the gas pipe is connected to the two branch pipes through a three-way joint.

[0012] Although the natural gas burner with the above structure can quickly disperse the natural gas in the combustion chamber and improve the mixing efficiency of air and natural gas, the air-fuel ratio is not the same under various working conditions, and the linkage valve group installed at the connection between the gas pipe and the two branch pipes still cannot adapt to every working condition.

[0013] Specifically, after the equipment equipped with the combustion system is installed, the operator will debug the air-fuel ratio under the assumption that the burner has different loads. Usually, the burner will be selected at 0%, 10%, 20%, and so on until 100%, and the corresponding valve opening will be debugged under ten different loads. Therefore, the linkage valve will reach the corresponding opening corresponding to the corresponding load of the burner. However, due to the limitations of the linkage valve itself, the delivery amount of the combustion-supporting air or the combustible gas cannot be adjusted separately during the debugging process, and sometimes a good air-fuel ratio curve cannot be adjusted.

[0014] To this end, it is also necessary to design an improved mixed gas combustion system based on the existing technology, which can independently control the delivery amount of combustion-supporting air and combustible gas, thereby solving the problem of poor air-fuel ratio performance of the linkage valve. Utility Model Content

[0015] The utility model aims to provide a mixed gas combustion system for a paper machine, which can independently control the delivery amount of combustion-supporting air and combustible gas, so as to obtain an ideal air-fuel ratio in a burner.

[0016] The mixed gas combustion system for a paper machine according to the present invention comprises:

[0017] at least one burner;

[0018] A combustion air delivery pipeline connected to the burner; and

[0019] The gas delivery pipeline connected to the burner,

[0020] The combustion-supporting air fan delivers the combustion-supporting air to the burner through the combustion-supporting air delivery pipeline.

[0021] The gas source transports the combustible gas to the burner through the gas transmission pipeline.

[0022] Each combustion-supporting air delivery branch connected to the burner by the combustion-supporting air delivery pipeline is equipped with a combustion-supporting air control valve for individually adjusting the air intake volume of the combustion-supporting air flowing through the combustion-supporting air delivery branch, and

[0023] Each gas delivery branch connected to the burner by the gas delivery pipeline is equipped with a gas control valve for individually adjusting the intake amount of the combustible gas flowing through the gas delivery branch.

[0024] In the above technical solution, the term "independent regulation" means that at least one combustion air control valve independently and unrelatedly regulates the intake amount of combustion air flowing through the combustion air delivery branch, and at least one gas control valve independently and unrelatedly regulates the intake amount of combustible gas flowing through the gas delivery branch.

[0025] Preferably, at least one burner includes a first burner and a second burner connected in series with each other, a combustion-supporting air delivery pipeline branches out into a first combustion-supporting air delivery branch and a second combustion-supporting air delivery branch, the first combustion-supporting air delivery branch and the second combustion-supporting air delivery branch are respectively connected in parallel to the first burner and the second burner, and a gas delivery pipeline branches out into a first gas delivery branch and a second gas delivery branch, the first gas delivery branch and the second gas delivery branch are respectively connected in parallel to the first burner and the second burner.

[0026] Preferably, the first combustion-supporting air delivery branch is equipped with a first combustion-supporting air control valve for the first burner, and the second combustion-supporting air delivery branch is equipped with a second combustion-supporting air control valve for the second burner. The first combustion-supporting air control valve independently adjusts the intake air volume of the combustion-supporting air flowing through the first combustion-supporting air delivery branch, and the second combustion-supporting air control valve independently adjusts the intake air volume of the combustion-supporting air flowing through the second combustion-supporting air delivery branch.

[0027] More preferably, the first gas delivery branch is equipped with a first gas control valve for the first burner, and the second gas delivery branch is equipped with a second gas control valve for the second burner, the first gas control valve individually adjusts the intake amount of combustible gas flowing through the first gas delivery branch, and the second gas control valve individually adjusts the intake amount of combustible gas flowing through the second gas delivery branch.

[0028] In a preferred embodiment, the mixed gas combustion system further comprises an inlet air valve arranged in the combustion-supporting air delivery pipeline, and the inlet air valve is arranged downstream of the combustion-supporting air fan.

[0029] In another preferred embodiment, the mixed gas combustion system further comprises a heat recovery line, which transports at least a portion of the hot air exhausted by the first burner and the second burner back to the upstream of the inlet air valve.

[0030] Preferably, the heat recovery line is equipped with a heat recovery air valve for adjusting the amount of hot air returned to the upstream of the inlet air valve via the heat recovery line 10 .

[0031] In yet another preferred embodiment, the mixed gas combustion system further includes a combustion air temperature detection device and / or a furnace differential pressure gauge.

[0032] In the above technical solution, the combustion-supporting wind is preferably air, and the combustible gas is preferably natural gas.

[0033] The mixed gas combustion system for a paper machine according to the utility model can obtain the following advantages:

[0034] (i) By changing the interlocking valves into separate combustion air and gas valves, the combustion system can obtain the desired air-fuel ratio when the air-fuel ratio curve of the burner controller needs to be debugged at the same time, so as to improve the combustion efficiency of the mixed gas combustion system.

[0035] (ii) The above combustion system is particularly suitable for occasions where the circulating gas supply is unstable. By finely adjusting the air-fuel ratio, the consumption of natural gas can be effectively saved, thereby achieving the purpose of energy saving and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to further illustrate the technical effect of the mixed gas combustion system for a paper machine according to the utility model, the utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments, wherein:

[0037] Figure 1 It is a brief schematic diagram of the existing mixed gas combustion system;

[0038] Figure 2 is a simplified schematic diagram of a mixed gas combustion system for a paper machine according to the utility model; and

[0039] Figure 3 is a graph showing the percentage reduction in natural gas consumption measured at different inlet air temperatures.

[0040] Reference numerals

[0041] 1 Combustion air fan

[0042] 2 Inlet air valve

[0043] 3 Combustion air delivery pipeline

[0044] 3a The first combustion air delivery branch

[0045] 3b Second combustion air delivery branch

[0046] 4 First linkage valve

[0047] 5 Second linkage valve

[0048] 6 First burner

[0049] 7 Second burner

[0050] 8 Gas transmission pipeline

[0051] 8a First gas transmission branch

[0052] 8b Second gas transmission branch

[0053] 9 Heat recovery damper

[0054] 10 Heat recovery pipeline

[0055] 11 First combustion air control valve

[0056] 12 Second combustion air control valve

[0057] 13 First gas control valve

[0058] 14 Second gas control valve

[0059] 100 Mixed gas combustion system

[0060] S Natural gas source DETAILED DESCRIPTION

[0061] The structure, operation process and technical effects of the mixed gas combustion system for a paper machine according to the utility model are explained below in conjunction with the accompanying drawings.

[0062] It should be clear that the embodiments described in this specification only cover some embodiments of the utility model, not all embodiments. Based on the embodiments recorded in the specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0063] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0064] Based on the same understanding of orientation, in the description of the present invention, the orientation or positional relationship indicated by the terms "upstream", "downstream", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0065] Figure 2 FIG. 1 shows a mixed gas combustion system 100 according to the present utility model. Figure 2As shown, the mixed gas combustion system 100 includes at least one burner 6 and 7, a combustion-supporting air delivery pipeline 3 and a gas delivery pipeline 8, wherein the combustion-supporting air blower 1 delivers the combustion-supporting air, preferably air, to at least one burner 6 and 7 via the combustion-supporting air delivery pipeline 3, and the natural gas source S delivers the combustible gas, preferably natural gas, to at least one burner 6 and 7 via the gas delivery pipeline 8. The first burner 6 and the second burner 7 are connected in series with each other to form a combustion unit. The combustion-supporting air delivery pipeline 3 branches out a first combustion-supporting air delivery branch 3a and a second combustion-supporting air delivery branch 3b, and the first combustion-supporting air delivery branch 3a and the second combustion-supporting air delivery branch 3b are respectively connected in parallel to the first burner 6 and the second burner 7. The gas delivery pipeline 8 branches out a first gas delivery branch 8a and a second gas delivery branch 8b, and the first gas delivery branch 8a and the second gas delivery branch 8b are respectively connected in parallel to the first burner 6 and the second burner 7.

[0066] The first combustion-supporting air delivery branch 3a and the second combustion-supporting air delivery branch 3b are respectively equipped with a first combustion-supporting air control valve 11 and a second combustion-supporting air control valve 12 for the first burner 6 and the second burner 7, and the first combustion-supporting air control valve 11 and the second combustion-supporting air control valve 12 are controlled independently of each other. More specifically, the first combustion-supporting air delivery branch 3a is equipped with a first combustion-supporting air control valve 11 for the first burner 6, and the second combustion-supporting air delivery branch 3b is equipped with a second combustion-supporting air control valve 12 for the second burner 7. The first combustion-supporting air control valve 11 independently adjusts the intake air volume of the combustion-supporting air flowing through the first combustion-supporting air delivery branch 3a, and the second combustion-supporting air control valve 12 independently adjusts the intake air volume of the combustion-supporting air flowing through the second combustion-supporting air delivery branch 3b.

[0067] The first gas transmission branch 8a and the second gas transmission branch 8b are respectively provided with a first gas control valve 13 and a second gas control valve 14 for the first burner 6 and the second burner 7, and the first gas control valve 13 and the second gas control valve 14 are controlled independently of each other. More specifically, the first gas transmission branch 8a is provided with the first gas control valve 13 for the first burner 6, and the second gas transmission branch 8b is provided with the second gas control valve 14 for the second burner 7, and the first gas control valve 13 independently adjusts the intake amount of the combustible gas flowing through the first gas transmission branch 8a, and the second gas control valve 14 independently adjusts the intake amount of the combustible gas flowing through the second gas transmission branch 8b.

[0068] The mixed gas combustion system 100 further includes an inlet air valve 2 disposed in the combustion-supporting air delivery pipeline 3, and the inlet air valve 2 is preferably disposed downstream of the combustion-supporting air blower 1. The mixed gas combustion system 100 further includes a heat recovery pipeline 10, which delivers a portion of the hot air exhausted by the first burner 6 and the second burner 7 to the atmosphere, and delivers another portion of the hot air back to the upstream of the inlet air valve 2.

[0069] The heat recovery line 10 is equipped with a heat recovery air valve 9 for adjusting the amount of hot air returned to the upstream of the inlet air valve 2 via the heat recovery line 10 .

[0070] In addition, since the power of the combustion-supporting air fan 1 increases from 37KW to 55KW, the original gas controller and control cabinet need to be replaced, and a combustion-supporting air temperature detection device and / or a furnace differential pressure gauge are added to debug the heat recovery efficiency and increase safety protection.

[0071] To sum up, by equipping each combustion-supporting air delivery branch 3a and 3b in the combustion-supporting air delivery pipeline 3 and each gas delivery branch 8a and 8b in the gas delivery pipeline 8 with an independent control valve, the delivery amounts of the combustion-supporting air and the combustible gas can be controlled individually to obtain the desired air-fuel ratio, thereby improving the combustion efficiency of the mixed gas combustion system according to the utility model and saving the consumption of natural gas.

[0072] The inventors of the present application calculated the natural gas consumption at different inlet air temperatures and found that if the inlet air temperature is used as the horizontal axis and the reduction ratio of natural gas consumption is used as the vertical axis, the following equation can be obtained: Figure 3 As shown in the straight line segment. It can be seen that when the inlet air temperature is 120℃, the reduction rate of natural gas consumption is about 5%; when the inlet air temperature rises to 300℃, the reduction rate of natural gas consumption is close to 14%. It can be seen that theoretically, the higher the temperature of the combustion-supporting air, the higher the reduction rate of natural gas consumption, or the higher the amount of natural gas saved. Considering the model and capacity of the burner itself, the combustion-supporting air is usually set to 160℃.

[0073] Of course, the above curve shows the theoretical natural gas savings. In the actual test, the natural gas consumption before the transformation was 33.47Nm per month. 3 / TP to 33.63Nm 3 / TP, and the natural gas consumption after the transformation is 29.4Nm 3 / TP, the saving effect is significant.

[0074] The operation process and working principle of the mixed gas combustion system for a paper machine according to the present invention will be described below.

[0075] First, close the heat recovery air valve 9. At this time, the recovery device is in a cold state, that is, it is not suitable for circulating waste heat. Optimize the parameters of the first burner 6 and the second burner 7, and debug the temperature rise curves of the two burners, that is, the corresponding gas valve opening and air valve opening under different loads of each burner.

[0076] Secondly, open the heat recovery air valve 9 and reach a certain opening degree. At this time, the recovery device is in a hot state, that is, a state suitable for circulating waste heat. As in the cold state, it is necessary to debug the hot burner air-fuel ratio to obtain the final temperature control curve. By adjusting the opening degree of the heat recovery valve 9, different air inlet temperatures can be obtained.

[0077] Although the structure and working principle of the mixed gas combustion system for a paper machine according to the utility model are described above in combination with the preferred embodiments and the accompanying drawings, it should be recognized by those skilled in the art that the above examples are only for illustration and cannot be used as a limitation of the utility model. Therefore, the utility model can be modified and varied within the spirit of the claims, and these modifications and variations will fall within the scope required by the claims of the utility model.

Claims

1. A mixed gas combustion system (100) for a paper machine, comprising: at least one burner (6, 7); A combustion-supporting air delivery pipeline (3) connected to the burners (6, 7); as well as a gas delivery pipeline (8) connected to the burners (6, 7), The combustion-supporting air fan (1) delivers the combustion-supporting air to the burners (6, 7) via the combustion-supporting air delivery pipeline (3). The gas source (S) delivers the combustible gas to the burners (6, 7) via the gas delivery pipeline (8). It is characterized in that Each combustion-supporting air delivery branch connected to the combustion-supporting air delivery pipeline (3) of the burners (6, 7) is equipped with a combustion-supporting air control valve for individually adjusting the air intake volume of the combustion-supporting air flowing through the combustion-supporting air delivery branch, and Each gas delivery branch connected to the gas delivery pipeline (8) of the burners (6, 7) is equipped with a gas control valve for individually adjusting the intake amount of the combustible gas flowing through the gas delivery branch.

2. The mixed gas combustion system (100) according to claim 1, characterized in that: The at least one burner (6, 7) comprises a first burner (6) and a second burner (7) connected in series with each other, The combustion-supporting air delivery pipeline (3) branches into a first combustion-supporting air delivery branch (3a) and a second combustion-supporting air delivery branch (3b); the first combustion-supporting air delivery branch (3a) and the second combustion-supporting air delivery branch (3b) are respectively connected in parallel to the first burner (6) and the second burner (7); The gas transmission pipeline (8) branches into a first gas transmission branch (8a) and a second gas transmission branch (8b), and the first gas transmission branch (8a) and the second gas transmission branch (8b) are respectively connected in parallel to the first burner (6) and the second burner (7).

3. The mixed gas combustion system (100) according to claim 2, characterized in that: The first combustion-supporting air delivery branch (3a) is equipped with a first combustion-supporting air control valve (11) for the first burner (6), and the second combustion-supporting air delivery branch (3b) is equipped with a second combustion-supporting air control valve (12) for the second burner (7). The first combustion-supporting air control valve (11) independently adjusts the intake volume of the combustion-supporting air flowing through the first combustion-supporting air delivery branch (3a), and the second combustion-supporting air control valve (12) independently adjusts the intake volume of the combustion-supporting air flowing through the second combustion-supporting air delivery branch (3b).

4. The mixed gas combustion system (100) according to claim 2, characterized in that: The first gas transmission branch (8a) is equipped with a first gas control valve (13) for the first burner (6), and the second gas transmission branch (8b) is equipped with a second gas control valve (14) for the second burner (7). The first gas control valve (13) independently adjusts the intake amount of the combustible gas flowing through the first gas transmission branch (8a), and the second gas control valve (14) independently adjusts the intake amount of the combustible gas flowing through the second gas transmission branch (8b).

5. The mixed gas combustion system (100) according to claim 2, characterized in that: The mixed gas combustion system (100) further comprises an inlet air valve (2) arranged in the combustion-supporting air delivery pipeline (3), wherein the inlet air valve (2) is arranged downstream of the combustion-supporting air blower (1).

6. The mixed gas combustion system (100) according to claim 5, characterized in that: The mixed gas combustion system (100) further comprises a heat recovery pipeline (10), wherein the heat recovery pipeline (10) transports at least a portion of the hot air exhausted by the first burner (6) and the second burner (7) back to the upstream of the inlet air valve (2).

7. The mixed gas combustion system (100) according to claim 6, characterized in that: The heat recovery pipeline (10) is equipped with a heat recovery air valve (9) for adjusting the amount of hot air returned to the upstream of the inlet air valve (2) via the heat recovery pipeline (10).

8. The mixed gas combustion system (100) according to claim 1, characterized in that: The mixed gas combustion system (100) further comprises a combustion air temperature detection device and / or a furnace differential pressure gauge.

9. The mixed gas combustion system (100) according to any one of claims 1 to 8, characterized in that: The combustion-supporting wind is air.

10. The mixed gas combustion system (100) according to any one of claims 1 to 8, characterized in that: The combustible gas is natural gas.

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