CN107255274A - A kind of low nitrogen burner for gas boiler - Google Patents

Abstract

The invention discloses a low-nitrogen gas-fired boiler burner, which comprises a mixing pipe, an igniter, a metal fiber combustion head, a gas flow control circuit, an air flow control circuit and a ratio device. The ratio device is arranged on the gas flow control circuit and the air flow control circuit. Between the loops, the gas flow control loop and the air flow control loop are adjusted to control the ratio of natural gas to air flow, so that the mixed gas flow and ratio are more stable, and the burner efficiency and boiler combustion safety are improved; two-stage air supply is adopted way, supplementing the pressure loss of primary air and gas in the twisted blade mixer, improving the mixing degree of natural gas and air, reducing the temperature of the metal fiber combustion head, reducing the residence time of flue gas in the high temperature area, and effectively suppressing the generation of NOx ; The air supplied by the secondary swirl flow makes the flame inside circulate, enhances the uniformity of the flame temperature, and improves the efficiency of the burner; the invention has strong innovation and wide practicability.

Description

A low nitrogen gas boiler burner

technical field

The invention relates to a burner, in particular to a low-nitrogen gas boiler burner.

Background technique

China's energy consumption structure is mainly based on the three major fossil fuels. In recent years, the consumption of coal and oil has shown a downward trend, while the consumption of natural gas has gradually increased. With the development of natural gas and shale gas around the world, the consumption of gas will continue to rise in the future. At the same time, with the development of the economy, the deterioration of the environment and the depletion of resources, the efficient use of energy and the discharge of pollutants have become important issues. NOx is the main pollutant in the air, which is very harmful to human health and ecological environment. The exhaust gas produced during the combustion process of the boiler is one of the main sources in the air, so the low-nitrogen transformation of the boiler burner is of great significance. In the prior art, the mixing of gas flow and air flow is unstable, resulting in unstable combustion, which not only affects production safety, but also affects thermal efficiency and NOx emissions. Moreover, due to unstable combustion, the control of primary air and combustion components are highly required.

Contents of the invention

Aiming at the deficiencies of the existing gas burner technology, a low-nitrogen gas boiler burner is provided. By stably controlling the flow ratio of air and gas, the gas can be fully combusted, the combustion stability can be improved, the safety can be improved, and the formation of NOx can be reduced. At the same time, the secondary air supply is used to further fully mix the air and gas, improve the efficiency of the burner, and at the same time reduce the residence time of the flue gas in the high temperature area, and further suppress and reduce the formation of NOx.

To achieve the above object of the invention, the present invention provides the following technical solutions:

The invention provides a low-nitrogen gas boiler burner, which includes a mixing pipe, an igniter, a metal fiber combustion head, a gas flow control circuit, an air flow control circuit and a ratio device, and the ratio device is arranged in the gas flow control circuit and the air flow control circuit Between; the gas flow control loop includes a flow signal transmitter, a flow controller and a control valve, the flow signal transmitter is connected to the flow controller signal, and the flow controller is connected to the control valve signal; the air flow control loop includes a flow signal changer transmitter, flow controller, control valve, fan and air filter, one end of the fan is connected to the air filter, the other end is connected to the flow transmitter, the flow signal transmitter is connected to the flow controller signal, the flow controller is connected to the control Valve signal connection; one end of the proportional flow valve is connected to the control valve, and the other end is respectively connected to the primary air inlet and the secondary air inlet of the mixing pipe; one end of the igniter is fixed on the mixing pipe, and the other end goes deep into the boiler; the flange of the mixing pipe passes through Bolts are fixed on the furnace wall; one end of the metal fiber combustion head passes through the furnace wall and is installed concentrically with the mixing pipe, and the other end is located in the boiler.

Further, a twisted blade mixer is installed in the primary air mixing section of the mixing pipeline.

Further, a swirl generating device is installed in the secondary air mixing pipe section in the mixing pipe.

Further, the ratio of the primary air to the secondary air distributed by the proportional flow valve is in a continuous range from 1:1 to 10:1.

Furthermore, the ratio of primary air to secondary air distributed by the proportional flow valve is 4:1.

The present invention also provides a gas-fired boiler, at least including any one of the above-mentioned low-nitrogen gas-fired boiler burners.

The beneficial effects of the present invention are: the gas flow control loop and the air flow control loop can effectively and stably control the ratio between the gas flow and the air flow, so that the flow of the mixed gas is stable, the efficiency of the burner can be improved, the emission of NOx can be reduced, and the The safety of the boiler during the combustion process. The gas and air can be further fully mixed through the two-stage air supply mode, and the temperature of the metal fiber combustion head can be reduced, and the pressure and speed loss of the air and gas in the twisted blade mixer can be supplemented once, so that the mixed gas flows into the furnace at a high speed and reduces The residence time of the high-temperature flue gas in the high-temperature zone can effectively suppress the generation of NOx; the air supplied by the secondary swirl makes the circulation flow inside the flame, enhances the uniformity of the flame temperature, and improves the efficiency of the burner;

Description of drawings

Fig. 1 is the complete machine front view of the present invention;

In the figure: 1-ratio, 2-flow signal transmitter, 3-flow controller, 4-control valve, 5-gas source, 6-twisted blade mixer, 7-swirl flow generating device, 8- Mixing pipeline, 9-metal fiber combustion head, 10-igniter, 11-fan, 12-air filter, 13-control valve, 14-flow signal transmitter, 15-flow controller, 16-proportional flow valve.

detailed description

The technical solutions of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Referring to Fig. 1, flow signal transmitter 2, flow controller 3, control valve 4 and gas source 5 constitute a gas flow control loop; flow signal transmitter 14, flow controller 15, control valve 13, fan 11 and The air filter 12 constitutes the air flow control circuit; a ratio device 1 is arranged between the gas flow control circuit and the air flow control circuit; one end of the proportional flow valve 16 is connected to the air flow control circuit, and the other end is respectively connected to the primary air inlet and The secondary air inlets are connected; one end of the igniter 10 is fixed on the mixing pipe 8, and one end goes deep into the boiler; one end of the metal fiber combustion head 9 is installed concentrically through the furnace wall and the mixing pipe 8, and the other end is located in the boiler.

When the gas flow rate of the gas source 5 changes, the flow signal transmitter 2 transmits the measured flow signal to the flow controller 3 on the one hand to control the gas flow to keep the gas flow at the set value; Device 1 is used as the setting value of the air flow controller circuit, so that the air flow and gas flow maintain a fixed ratio; when the gas flow is stable and the air flow changes, the flow signal transmitter 14 transmits the measured flow signal to the flow control The device 15 controls the air flow to keep the flow at the set value, so that the air flow and the gas flow maintain a fixed ratio, realizing the precise control of the ratio of the gas flow and the gas-air flow, and enhancing the anti-interference ability of the gas flow.

In this embodiment, the primary air mixing pipe in the mixing pipe 8 is equipped with a twisted vane mixer 6, which improves the mixing characteristics of gas and primary air, and can effectively reduce the amount of NOx generated during the combustion of gas.

The secondary air mixing pipeline in the mixing pipeline 8 is equipped with a swirl generating device 7, and the secondary air flows out in a strong swirling manner, and a large negative pressure is generated in the central area of the mixer, so that a circulating flow occurs inside the flame, ensuring The uniformity of the flame temperature is improved, and the efficiency of the burner is improved.

This embodiment adopts the two-stage air supply mode, and the flow is distributed through the proportional flow valve 16. The ratio of the primary air and the secondary air distributed by the proportional flow valve 16 is a continuous section within 1:1 to 10:1, and the adjustability Higher, the optimal ratio is 4:1. The primary air and gas are fully mixed in the twisted blade mixer 6, and the secondary air enters the metal fiber combustion head 9 from around the outlet of the twisted blade mixer 6, which can not only reduce the temperature of the metal fiber combustion head 9, but also supplement the primary air and The pressure and speed loss of the gas in the twisted blade mixer makes the mixed gas flow into the furnace at a high speed, reduces the residence time of the flue gas in the high temperature area, and further reduces the amount of NOx generated.

It should be noted that: the embodiments of the present invention are preferred implementations, not limitations thereto. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, modifications to the specific implementation or equivalent replacement of some technical features can be made, all of which should be regarded as part of the scope of the present invention. protected range.

Claims (6)

1. A low-nitrogen gas-fired boiler burner, comprising a mixing pipe (8), an igniter (10), a metal fiber combustion head (9), a gas flow control circuit, an air flow control circuit and a ratio device (1), its characteristics In that: the ratio device (1) is set between the gas flow control circuit and the air flow control circuit; the gas flow control circuit includes a flow signal transmitter (2), a flow controller (3) and a control valve ( 4), the flow signal transmitter (2) is connected to the flow controller (3) signal, and the flow controller (3) is connected to the control valve (4) signal; the air flow control circuit includes a flow signal transmitter (14 ), flow controller (15), control valve (13), fan (11) and air filter (12), described fan (11) one end is connected with air filter (12), and the other end is connected with flow transmitter device (14), the flow signal transmitter (14) is connected to the flow controller (15) signal, and the flow controller (15) is connected to the control valve (13) signal; one end of the proportional flow valve (16) is connected to the control valve ( 13) connection, the other end is connected with the primary air inlet and the secondary air inlet of the mixing pipe (8) respectively; one end of the igniter (10) is fixed on the mixing pipe (8), and one end goes deep into the boiler; the mixing The flange of the pipe (8) is fixed on the furnace wall by bolts; one end of the metal fiber combustion head (9) passes through the furnace wall and is installed concentrically with the mixing pipe (8), and the other end is located in the boiler. 2. The low-nitrogen gas-fired boiler burner according to claim 1, characterized in that: a twisted blade mixer (6) is installed in the primary air mixing pipe section of the mixing pipe (8). 3. The low-nitrogen gas-fired boiler burner according to claim 1 or 2, characterized in that a swirl generating device (7) is installed in the secondary air mixing pipe section of the mixing pipe (8). 4. The low-nitrogen gas-fired boiler burner according to claim 1, characterized in that: the proportional flow valve (16) can distribute the ratio of primary air to secondary air within a continuous range of 1:1 to 10:1. segment. 5. The low-nitrogen gas-fired boiler burner according to claim 1 or 4, characterized in that: said proportional flow valve (16) can distribute the ratio of primary air to secondary air as 4:1. 6. A gas boiler, characterized in that it includes at least the low nitrogen gas boiler burner as claimed in any one of claims 1-5.