Control system for oxygen-enriched combustion device of gas-fired boiler

Abstract

The utility model provides a control system for an oxygen-enriched combustion device of a gas-fired boiler, and the oxygen-enriched combustion device of the gas-fired boiler comprises a burner fire tube, a gas supply pipeline, a burner air blower and an oxygen-enriched system, the gas supply pipeline is communicated with the burner fire tube so as to supply fuel to the burner fire tube, the burner air blower is communicated with the other end of the burner fire tube so as to provide combustion-supporting air for combustion, the oxygen enrichment system is communicated with the middle end of the burner fire tube, and the control system comprises a combustion program controller. The combustion program controller is connected to the combustor air blower, the fuel gas supply pipeline and the oxygen enrichment system to provide a control instruction, a fault signal of the combustion program controller and a fault signal of the oxygen enrichment system interact with each other, the system can enable fuel gas to be combusted in an oxygen-enriched environment, higher combustion temperature is generated, and the combustion efficiency is improved. And the fuel gas in unit volume can generate higher energy.

Description

Technical Field

[0001] This utility model belongs to the technical field of boiler combustion equipment and facilities, specifically relating to a control system for an oxygen-enriched combustion device for a gas-fired boiler. Background Technology

[0002] Oxygen-enriched combustion is an emerging combustion technology. With advancements in oxygen production methods, especially oxygen-enriched membrane technology, oxygen-enriched combustion technology has been gradually promoted in recent years. Moreover, its application in boiler retrofitting has promising prospects. Currently, oxygen-enriched combustion is relatively mature in foreign countries and industrial kilns. In addition, oxygen-enriched combustion technology has also appeared in the aviation and marine combustion fields. Oxygen-enriched combustion technology refers to combustion in which the oxygen content of the air used for combustion exceeds 20.94%. The increase in the oxygen content of the air reduces the amount of inert gases in the air, theoretically increasing the combustion temperature. The increased oxygen content in the air also reduces the amount of flue gas produced by combustion, and the heat carried away by the flue gas is reduced accordingly. This not only increases the combustion temperature but also achieves the goal of energy conservation and emission reduction.

[0003] Currently, oxygen-enriched combustion technology is not yet mature enough for use in small civilian boilers in China. After China implemented low-NOx retrofitting, oxygen-enriched combustion urgently needs to fill the gap in low-NOx boilers for the purpose of energy conservation and emission reduction. However, due to the heat resistance and safety of boilers, there are still some problems with oxygen-enriched combustion control technology and processes.

[0004] For example, Chinese invention patent application CN202010904505.6 discloses an oxygen-enriched low-NOx burner for a boiler, which includes a primary air duct for introducing primary air and pulverized coal. The key feature is that a rich-lean separation device, a primary combustion chamber, and a secondary combustion chamber are sequentially arranged in the primary air duct along the flow direction of the primary air and pulverized coal. Both the primary and secondary combustion chambers are cylindrical and are arranged along the same center line as the primary air duct.

[0005] The outlet of the primary combustion chamber is close to the inlet of the secondary combustion chamber;

[0006] At least one air distribution duct is provided outside the primary air duct, and the air distribution duct extends along the primary air duct beyond its outlet end;

[0007] The primary combustion chamber is equipped with an oxygen-enriched fuel gun assembly, which passes through the primary air duct and the cylinder wall of the primary combustion chamber from the outside to the inside. The nozzle of the oxygen-enriched fuel gun assembly is located inside the primary combustion chamber.

[0008] The aforementioned existing technology uses an oxygen-enriched fuel gun assembly to provide an oxygen-enriched combustion environment, which cannot achieve precise control over the delivery of oxygen. In addition, the method of directly adding fuel into the fuel pipeline for mixing and combustion significantly increases the oxygen content beyond the original control. When detecting the tail gas, the oxygen content value is directly increased. This increases the combustion temperature while also removing most of the heat.

[0009] Based on the aforementioned technical problems existing in the prior art, this utility model proposes a control system for an oxygen-enriched combustion device for a gas-fired boiler. Utility Model Content

[0010] The purpose of this invention is to address the shortcomings of existing technologies by providing a control system for an oxygen-enriched combustion device in a gas-fired boiler.

[0011] This utility model provides a control system for an oxygen-enriched combustion device in a gas-fired boiler. The oxygen-enriched combustion device includes a burner tube, a gas supply pipeline, a burner blower, and an oxygen-enriched system. One end of the burner tube serves as a flame nozzle. The gas supply pipeline is connected to the burner tube to supply fuel to it. The burner blower is connected to the other end of the burner tube to provide combustion-supporting air. The oxygen-enriched system is connected to the middle of the burner tube. The control system includes a combustion programmable controller, which is connected to the burner blower, the gas supply pipeline, and the oxygen-enriched system to provide control commands. Fault signals from the combustion programmable controller and fault signals from the oxygen-enriched system interact with each other.

[0012] Furthermore, the gas supply pipeline is provided with a gas valve assembly, a flame arrester, and a gas valve in sequence from upstream to downstream, and the gas valve assembly, the flame arrester, and the gas valve are all connected to the combustion program controller.

[0013] Furthermore, an energy-saving stack device is connected upstream of the gas supply pipeline, and the energy-saving stack device is connected between the gas valve group and the flame arrester on the gas supply pipeline through an energy-saving control pipeline.

[0014] Furthermore, a shut-off valve, an air valve, a check valve, and a control valve are provided downstream of the energy-saving control pipeline, and the control valve is connected to the combustion programmable controller via a first servo motor.

[0015] Furthermore, an electromagnetic valve, a flow meter, and a pressure regulating valve are installed upstream of the energy-saving control pipeline, and the electromagnetic valve, the flow meter, and the pressure regulating valve are all connected to the oxygen-enriched system.

[0016] Furthermore, a differential pressure device is connected between the oxygen enrichment system and the energy-saving control pipeline. The differential pressure device is connected to the energy-saving control pipeline via a first connecting line and a second connecting line. The first connecting line is connected between the control valve and the solenoid valve, and the second connecting line is connected between the solenoid valve and the flow meter.

[0017] Furthermore, a burner fault interlocking communication line is connected between the combustion program controller and the oxygen enrichment system.

[0018] Furthermore, an oxygen-enriched system fault interlocking communication line is connected between the combustion program controller and the oxygen-enriched system.

[0019] Furthermore, a pressure transmitter is installed on the gas supply pipeline, the pressure transmitter is located between the flame arrester and the gas valve, and the pressure transmitter is connected to the oxygen enrichment system.

[0020] Furthermore, the oxygen-enriched combustion device of the gas boiler includes a flue gas circulation device, which is connected between the boiler's chimney and the burner's furnace. The flue gas circulation device is equipped with a fourth servo motor, which is connected to the combustion program controller.

[0021] Furthermore, the oxygen-enriched combustion device for the gas-fired boiler includes an exhaust gas oxygen content detection device, which is installed at the chimney outlet and connected to the combustion program controller.

[0022] Furthermore, the oxygen-enriched system includes an oxygen-enriched generating device and an oxygen-enriched PLC for controlling the operation of the oxygen-enriched generating device.

[0023] The beneficial effects of this utility model are:

[0024] The gas-fired boiler oxygen-enriched combustion device control system of this utility model, through the coordinated setting of combustion program controller and oxygen-enriched system, enables gas to burn in an oxygen-enriched environment, producing a higher combustion temperature and generating more energy per unit volume of gas. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the control system of the gas-fired boiler oxygen-enriched combustion device in an embodiment of the present invention.

[0026] In the diagram, 1-combustion programmable controller, 2-energy-saving reactor equipment, 3-second servo motor, 4-burner blower, 5-shut-off valve, 6-first servo motor, 7-third servo motor, 8-burner fire tube, 9-flame nozzle, 10-burner fault interlocking line, 11-oxygen-enriched system fault interlocking line, 12-pressure transmitter, 13-flame arrester, 14-air valve, 15-check valve, 16-solenoid valve, 17-flow meter, 18-differential pressure device, 19-pressure regulating valve, 20-gas valve assembly, 21-oxygen-enriched system, 22-fourth servo motor, 23-flue gas recirculation device, 24-gas supply pipeline. Detailed Implementation

[0027] To better understand the above-mentioned objectives, features and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0028] Example

[0029] like Figure 1 As shown, a control system for an oxygen-enriched combustion device in a gas-fired boiler is disclosed. The oxygen-enriched combustion device includes a burner tube 8, a gas supply pipe 24, a burner blower 4, and an oxygen-enriched system 21. One end of the burner tube 8 serves as a flame nozzle 9. The gas supply pipe 24 is connected to the burner tube 8 to supply fuel to the burner tube 8. The burner blower 4 is connected to the other end of the burner tube 8 to provide combustion-supporting air. The oxygen-enriched system 21 is connected to the middle end of the burner tube 8. The control system includes a combustion program controller 1, which is connected to the burner blower 4, the gas supply pipe 24, and the oxygen-enriched system 21 to provide control commands.

[0030] The combustion program controller 1 is connected to the burner blower 4 via the second servo motor 3;

[0031] In this embodiment, the PID control valve in the prior art is replaced by the fusion of the oxygen-enriched system 21 and the combustion programmable controller 1. The redundant servo motor channels of the low-NOx burner are utilized (the low-NOx burner programmable controller generally has at least 4 channels, and the fourth channel is used) to control the oxygen-enriched flow of the oxygen-enriched system 21. The channel opening is set according to the air-fuel ratio adjustment for each load curve, and the oxygen-enriched flow is controlled during operation. In addition, the fault signals of the combustion programmable controller 1 and the fault signals of the oxygen-enriched system 21 interact with each other, and the fusion of oxygen-enriched control and low-NOx burner programmable controller is realized through interlocking control.

[0032] In a specific implementation, the gas supply pipeline 24 is provided with a gas valve group 20, a flame arrester 13, and a gas valve in sequence from upstream to downstream. The gas valve group 20, the flame arrester 13, and the gas valve are all connected to the combustion program controller 1.

[0033] The flame arrester 13 is used to prevent backfire in the burner by shutting off the gas pipeline in the event of backfire to prevent the flame from continuing to propagate forward. For example, the flame arrester 13 is a mechanical backfire device.

[0034] The gas valve is connected to the combustion program controller via a third servo motor 7;

[0035] The upstream of the gas supply pipeline 24 is connected to the energy-saving stack device 2, and the energy-saving stack device 2 is connected between the gas valve group 20 and the flame arrester 13 on the gas supply pipeline 24 through an energy-saving control pipeline;

[0036] Downstream of the energy-saving control pipeline are a shut-off valve 5, an air valve 14, a check valve 15, and a control valve. The control valve is connected to the combustion program controller 1 via a first servo motor 6. The shut-off valve 5 is downstream of the air valve 14, and the air valve 14 is downstream of the check valve 15. The shut-off valve 5 is close to the gas supply pipeline 24. When the boiler, burner, or oxygen-enriched control equipment malfunctions, the control system cuts off the control signal of the shut-off valve 5, stopping the oxygen-enriched gas supply. The shut-off valve 5 is controlled by a signal, while the air valve 14 is manually controlled. The check valve 15 controls the oxygen-enriched gas in one direction, allowing it to flow only from the energy-saving stack side to the burner side, preventing it from flowing back from the burner side to the energy-saving stack side. When backfire occurs, the fault signal first cuts off the shut-off valve 5, which is the upstream defense line. If the shut-off valve 5 experiences a closing delay or fails to shut off, the check valve 15 cuts off the flame. The air valve 14 controls the oxygen enrichment of the system manually, which also facilitates maintenance.

[0037] An electromagnetic valve 16, a flow meter 17, and a pressure regulating valve 19 are provided upstream of the energy-saving control pipeline. The electromagnetic valve 16, the flow meter 17, and the pressure regulating valve 19 are all connected to the oxygen-enriched system 21. The electromagnetic valve 16 is downstream of the flow meter 17, the flow meter 17 is downstream of the pressure regulating valve 19, and the pressure regulating valve 19 is close to the energy-saving stack device 2.

[0038] The energy-saving stack device 2 can be an oxygen-enriched device. After the energy-saving stack device 2 draws in air, it separates nitrogen into the atmosphere through internal membrane technology to produce 26%-30% oxygen-enriched gas. The produced oxygen-enriched gas participates in the combustion of fuel gas, generating high-temperature heat and achieving energy saving.

[0039] A differential pressure device 18 is connected between the oxygen enrichment system 21 and the energy-saving control pipeline. The differential pressure device 18 is connected to the energy-saving control pipeline through a first connecting line and a second connecting line. The first connecting line is connected between the control valve and the solenoid valve 16, and the second connecting line is connected between the solenoid valve 16 and the flow meter 17.

[0040] The differential pressure device 18 is used to check the pressure difference before and after the solenoid valve 16. When the burner is running, if the pressure difference between the inlet and outlet of the solenoid valve 16 is less than the set value, the control system will close the opening of the solenoid valve in time. If the pressure difference between the inlet and outlet of the solenoid valve 16 is greater than the set value, the control system will open the opening of the solenoid valve in time, so as to achieve stable combustion operation.

[0041] The combustion program controller 1 and the oxygen enrichment system 21 are connected by a burner fault interlock communication line 10. When a combustion-related fault occurs, for example, the burner does not work, the combustion program controller 1 sends the fault information to the oxygen enrichment system 21 through the burner fault interlock communication line 10. After receiving the fault signal, the oxygen enrichment system 21 stops oxygen production and oxygen delivery.

[0042] The combustion controller 1 and the oxygen-enriched system 21 are connected by an oxygen-enriched system fault interlocking communication line 11. When a fault related to oxygen production and delivery occurs, the oxygen-enriched system 21 sends the fault information to the combustion controller 1 through the oxygen-enriched system fault interlocking communication line 11. For example, when the fault is that the oxygen supply pressure is greater than the upper limit of the supply pressure threshold or less than the lower limit of the supply pressure threshold, the combustion controller 1 issues a command to stop combustion operation. When the fault is that the oxygen supply pressure is greater than the upper limit of the supply pressure threshold or less than the lower limit of the supply pressure threshold, both of these limits indicate a problem with the oxygen-enriched system 21, and a fault signal must be sent to the combustion controller 1 through the oxygen-enriched system fault interlocking communication line 11 to prevent oxygen deficiency during oxygen-enriched combustion and excessive oxygen content in the flue gas after combustion.

[0043] A pressure transmitter 12 is provided on the gas supply pipeline 24. The pressure transmitter 12 is located between the flame arrester 13 and the gas valve. The pressure transmitter 12 is connected to the oxygen enrichment system 21.

[0044] The oxygen-enriched combustion device of the gas boiler includes a flue gas circulation device 23, which is connected between the boiler chimney and the furnace of the burner. The flue gas circulation device 23 is equipped with a fourth servo motor 22, which is connected to the combustion program controller 1.

[0045] The oxygen-enriched combustion device for the gas-fired boiler includes an exhaust gas oxygen content detection device, which is installed at the chimney outlet and connected to the combustion program controller 1.

[0046] The oxygen-enriched system 21 includes an oxygen-enriched generating device and an oxygen-enriched PLC for controlling the operation of the oxygen-enriched generating device. For example, the oxygen-enriched generating device adopts an oxygen-enriched generator or oxygen-enriched membrane technology.

[0047] This utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims.

Claims

1. A control system for an oxygen-enriched combustion device in a gas-fired boiler, the oxygen-enriched combustion device comprising a burner fire tube, a gas supply pipeline, a burner blower, and an oxygen-enriched system, wherein one end of the burner fire tube serves as a flame nozzle, the gas supply pipeline is connected to the burner fire tube to supply fuel to the burner fire tube, the burner blower is connected to the other end of the burner fire tube to provide combustion-supporting air, and the oxygen-enriched system is connected to the middle end of the burner fire tube, characterized in that, The control system includes a combustion programmable controller connected to the burner blower, the gas supply pipeline, and the oxygen enrichment system to provide control commands. The combustion programmable controller fault signal and the oxygen enrichment system fault signal interact with each other.

2. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 1, characterized in that, The gas supply pipeline is connected in sequence from upstream to downstream to a gas valve assembly, a flame arrester, and a gas valve. The gas valve assembly, the flame arrester, and the gas valve are all connected to the combustion programmable controller.

3. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 2, characterized in that, An energy-saving stack device is connected upstream of the gas supply pipeline. The energy-saving stack device is connected between the gas valve group and the flame arrester on the gas supply pipeline through an energy-saving control pipeline.

4. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 3, characterized in that, Downstream of the energy-saving control pipeline are a shut-off valve, an air valve, a check valve, and a control valve. The control valve is connected to the combustion programmable controller via a first servo motor.

5. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 4, characterized in that, An electromagnetic valve, a flow meter, and a pressure regulating valve are installed upstream of the energy-saving control pipeline. The electromagnetic valve, the flow meter, and the pressure regulating valve are all connected to the oxygen-enriched system.

6. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 5, characterized in that, A differential pressure device is connected between the oxygen enrichment system and the energy-saving control pipeline. The differential pressure device is connected to the energy-saving control pipeline via a first connecting line and a second connecting line. The first connecting line is connected between the control valve and the solenoid valve, and the second connecting line is connected between the solenoid valve and the flow meter.

7. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 1, characterized in that, A burner fault interlocking line is connected between the combustion program controller and the oxygen enrichment system.

8. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 1 or 7, characterized in that, The combustion program controller and the oxygen-enriched system are connected by an oxygen-enriched system fault interlocking line.

9. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 2, characterized in that, A pressure transmitter is installed on the gas supply pipeline. The pressure transmitter is located between the flame arrester and the gas valve and is connected to the oxygen-enriched system.

10. The control system for the oxygen-enriched combustion device of a gas-fired boiler according to claim 1, characterized in that, The oxygen-enriched combustion device for the gas-fired boiler includes a flue gas circulation device, which is connected between the boiler's chimney and the burner's furnace. The flue gas circulation device is equipped with a fourth servo motor, which is connected to the combustion program controller.

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