CN211176766U - System for reducing content of nitrogen oxides in tail gas of natural gas boiler - Google Patents

Abstract

The utility model relates to a system for reduce natural gas boiler tail gas nitrogen oxide content, including flue gas reflux system and oxygen feed system, flue gas reflux system includes flue gas backflow pipeline, flue gas backward flow volume control flap and the flue of discharging fume that sets up with boiler intercommunication, the oxygen feed system includes air-blower, intake stack and intake control blast gate, in the air-blower import installation intake stack, the intake stack end is installed intake control blast gate; one end of the smoke backflow pipeline is connected with the smoke exhaust flue, and the other end of the smoke backflow pipeline is connected with the air inlet pipeline and is arranged behind the air inlet quantity control air valve; and a smoke reflux quantity control valve is also arranged in the middle of the smoke reflux pipeline. The utility model has the advantages that: the natural gas boiler is modified, the air inlet amount is adjusted, and the low-nitrogen oxide combustion technology is applied to reduce the emission of nitrogen oxides by changing the combustion conditions.

Description

System for reducing content of nitrogen oxides in tail gas of natural gas boiler

Technical Field

The utility model belongs to the technical field of the atmosphere environmental protection, in particular to system for reducing natural gas boiler tail gas nitrogen oxide content.

Background

Nitrogen oxides, including various compounds, such as nitrous oxide (N2O), Nitric Oxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O3), nitrous tetroxide (N2O4), and nitrous pentoxide (N2O5), among others. Besides nitrogen dioxide, other nitrogen oxides are extremely unstable and change into nitrogen dioxide and nitric oxide when exposed to light, moisture or heat, and nitric oxide changes into nitrogen dioxide again. Thus, the occupational environment is exposed to several gas mixtures, commonly known as niter fumes (gases), mainly nitrogen monoxide and nitrogen dioxide, and mainly nitrogen dioxide. Nitrogen oxides all have varying degrees of toxicity.

With the development of industry, boilers are used more and more, the problem of environmental pollution caused by the increase of smoke emission is more and more serious, and corresponding tail gas treatment methods or facilities are produced accordingly.

There are two methods for reducing boiler flue gas at present:

1. selective catalytic reduction process

Catalyst selective reduction is based on the reaction of ammonia and nitrogen oxides. This process selects ammonia as the reducing agent, and metal-based and carbon-based catalysts. Generally, ammonia is sprayed into the flue gas between the economizer and the air preheater. The ammonia and flue gas mixture passes through the catalyst bed where the ammonia and nitrogen oxides react to form nitrogen and water vapor.

2. Non-selective catalytic reduction process

Reducing agent NH under the condition of no catalyst at proper temperature₃Converting the nitrogen oxides into ammonia molecules and water.

The two methods have high cost in actual operation, have non-ideal treatment effect and have non-ideal effect on environmental protection treatment.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a system for reducing natural gas boiler tail gas nitrogen oxide content, through reforming transform the natural gas boiler, adjust the intake, use low nitrogen oxide combustion technology to realize nitrogen oxide's reduction emission through changing the combustion condition.

In order to solve the technical problem, the utility model adopts the technical scheme that: the utility model provides a system for reduce natural gas boiler tail gas nitrogen oxide content which innovation point lies in: comprises a flue gas reflux system and an oxygen supply system,

the flue gas reflux system comprises a flue gas reflux pipeline, a flue gas reflux control valve and a smoke exhaust flue communicated with the boiler,

the oxygen supply system comprises a blower, an air inlet pipeline and an air inlet quantity control air valve,

an air inlet pipeline is arranged at the inlet of the blower, and an air inlet quantity control air valve is arranged at the tail end of the air inlet pipeline;

one end of the smoke backflow pipeline is connected with the smoke exhaust flue, and the other end of the smoke backflow pipeline is connected with the air inlet pipeline and is arranged behind the air inlet quantity control air valve; and a smoke reflux quantity control valve is also arranged in the middle of the smoke reflux pipeline.

The utility model has the advantages that: the utility model discloses reduce natural gas boiler tail gas nitrogen oxide content's system uses the method that reduces tail gas nitrogen oxide content through the flue gas backward flow, utilizes the original wind channel and the air-blower of discharging fume of boiler, uses low nitrogen oxide combustion technology, through very simple transformation just can reach nitrogen oxide in the effectual reduction tail gas, economy and high efficiency.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Figure 1 is the utility model discloses reduce the structural schematic diagram of the system of natural gas boiler tail gas nitrogen oxide content.

Detailed Description

The following examples are presented to enable those skilled in the art to more fully understand the present invention and are not intended to limit the scope of the present invention.

Examples

The system for reducing the content of nitrogen oxides in the tail gas of the natural gas boiler, as shown in fig. 1, includes a flue gas recirculation system and an oxygen supply system.

The flue gas reflux system comprises a flue gas reflux pipeline 1, a flue gas reflux control valve 2 and a flue gas exhaust 3 communicated with the boiler, and the oxygen supply system comprises an air blower 4, an air inlet pipeline 6 and an air inlet amount control air valve 5.

An air inlet pipeline 6 is arranged at the inlet of the blower 4, an air inlet amount control air valve 5 is arranged at the tail end of the air inlet pipeline 6, one end of the flue gas backflow pipeline 1 is connected with the smoke exhaust flue 3, and the other end of the flue gas backflow pipeline 1 is connected with the air inlet pipeline 6 and is arranged behind the air inlet amount control air valve 5; a smoke reflux quantity control valve 2 is also arranged in the middle of the smoke reflux pipeline 1.

The boiler smoke and air are mixed by adjusting the opening degree of the air inlet quantity control air valve 5 and the opening degree of the smoke backflow quantity control valve 2, and the mixture is sent to the boiler for reutilization, so that the content of nitrogen oxides in the boiler smoke is reduced.

Operation example:

1. the air inlet control air valve 5 is kept fully opened, and the flue gas backflow control valve 2 is fully closed.

2. And (4) igniting the boiler according to a normal ignition procedure, and detecting the content of nitrogen oxides in the tail gas after the boiler normally runs so as to more accurately regulate.

3. Opening the flue gas reflux control valve 2 to an opening degree of 30%, closing the air inlet control valve 5 to an opening degree of not 60%, observing the operation condition of the boiler, and detecting the content of nitrogen oxides in the tail gas.

4. According to the method, the flue gas reflux control valve 2 and the air intake control valve 5 are slowly adjusted, and the content of nitrogen oxides in the tail gas is detected in time.

5. Attention is paid to observing the operation condition of the boiler and the content of nitrogen oxides in the tail gas.

The basic principles and main features of the invention and the advantages of the invention have been shown and described above. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the foregoing embodiments and descriptions are provided only to illustrate the principles of the present invention without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (1)

1. The utility model provides a system for reduce natural gas boiler tail gas nitrogen oxide content which characterized in that: comprises a flue gas reflux system and an oxygen supply system,

the flue gas reflux system comprises a flue gas reflux pipeline, a flue gas reflux control valve and a smoke exhaust flue communicated with the boiler,

the oxygen supply system comprises a blower, an air inlet pipeline and an air inlet quantity control air valve,

an air inlet pipeline is arranged at the inlet of the blower, and an air inlet quantity control air valve is arranged at the tail end of the air inlet pipeline;

one end of the smoke backflow pipeline is connected with the smoke exhaust flue, and the other end of the smoke backflow pipeline is connected with the air inlet pipeline and is arranged behind the air inlet quantity control air valve; and a smoke reflux quantity control valve is also arranged in the middle of the smoke reflux pipeline.

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