Low nox burners

Types of low NOx burners

There are several types of low NOx burners that reduce nitrogen oxides emissions. They work differently and have their own strengths.

• Staged combustion burners: This kind of low NOx industrial burner makes the fuel to have a rich and poor section during burning. In the first stage, there is more unburnt fuel which results in less oxygen and lower temperatures. The second stage has more oxygen and higher temperatures. The two sections help to reduce the amount of NOx that is formed. Low staged combustion NOx burners are popular in the industry.
• FGR burners: The FGR stands for Flue Gas Recirculation. This type of burner gets the CO2 that is produced during fuel burning and puts it back into the burner. The CO2 helps to lower the amount of oxygen in the burner, which in turn lowers the temperature. Both of them help to decrease nitric oxide formation.
• Low primary air burners: This kind of burner has special ways for air to come in. It reduces the air that goes into the fire. By doing this, it lowers the temperature by increasing the amount of fuel that is in the burner.
• Separate combustion burners: This type of burner separates fuel and air. They first mix the fuel and air before burning. By doing this, they control air-fuel ratios very well, reduce peak temperatures, and lower NOx formation. Low separation combustion NOx burners are effective for large-scale operations.
• Ultra-low NOx burners: These advanced burners use the technique of staged combustion and fuel/air linking to reduce the formation of NOx. They have a good performance record in reducing NOx emissions.
• Ox-fuel burners: This type of burner makes use of the oxidant called oxygen instead of normal air, which has 78% nitrogen. By doing this, it lowers the amount of nitrogen in the combustion process, hence lowering the production of NOx.

Specification and Maintenance of Low NOX Burners

Specifications

• Energy:

  Low-NOx gas burners are designed to operate on different gas types. Low NOx natural gas burners are made to work specifically with natural gas. On the other hand, low NOx propane burners are made to utilize propane as fuel.

• Emission:

  It is measured in parts per million (ppm). For example, some burners may be designed to produce less than 30 parts per million of NOx, which is considered to be very low. Other burners can produce less than 40 ppm of NOx. To achieve this, some manufacturers use precise combustion control techniques and advanced air-fuel mixing.

• Fan:

  A low NOx induced draft burner uses a fan to pull combustion gases out of the furnace and induce the proper draft for combustion to take place. This is sometimes referred to as a forced draft burner. A low NOx burner with a low external draft design will operate well, even in atmospheric conditions with low combustion gas drafts.

• Stages:

  Low NOx burners are often designed to have distinct stages of combustion. Some of them may have a two-stage or multi-stage design. Two-stage low NOx burners operate in a high-capacity primary combustion stage and a secondary stage of post-combustion. Multi-stage models have a more complex configuration with several combustion stages. This allows for a more optimized mixing of air and fuel, which in turn helps to reduce the formation of NOx gases.

Maintenance

• Regular Inspections:

  Carry out routine inspections of the burner components such as air/fuel control valves, mixing assemblies, and tilting mechanisms. Also, look for any signs of gas leakage including hissing noises or unusual smells. If any is found, evacuate the area immediately and seek professional assistance.

• Clean the Burners:

  As a general rule, avoid the use of abrasive materials or harsh chemicals that can damage combustion surfaces or air passages. Cleaning of low NOx burners can be done with a soft cloth or brush to remove sooty deposits and dirt. Consider using a vacuum cleaner with a soft brush attachment for hard-to-reach areas.

• Pay Attention to Air/Fuel Ratios:

  Low NOx burners function efficiently when air and fuel are properly mixed. The combustion process will be affected if this is not the case. This can lead to increase NOx emissions, higher fuel consumption and reduced efficiency. Monitor the air/fuel ratio and ensure the actuators and sensors controlling it are functioning properly.

• Keep a Log:

  It is important to monitor the performance characteristics of the burner system and any maintenance activities performed on it. This information should be kept in a record. If anything goes wrong, reviewing the maitenance log can provide insights into when the problem started and what changes were made just before it arose.

Application scenarios of low NOx burners

Due to their strict emission standards, low NOx burners have a wide range of application scenarios in many industries.

• Power industry: The power industry is one of the main application scenarios for low NOx burners, especially thermal power plants. In this industry, low NOx burners are primarily used to control NOx emissions during the combustion process to meet environmental protection requirements.
• Industrial manufacturing: In industrial manufacturing, low NOx burners are widely used in metal smelting, cement production, chemical processing, and other industries. For example, in the steel industry, low NOx burners can be used in blast furnaces, electric arc furnaces, and other equipment. This reduces the generation of nitrogen oxides.
• Municipal facilities: Municipal facilities include wastewater treatment, solid waste treatment, etc. Low NOx burners can be used in the incineration links of municipal facilities. For example, in waste incineration treatment, low NOx burners can reduce the generation of nitrogen oxides.
• Aerospace and aviation: Low NOx burners are used in the aerospace and aviation industries.
• Marine industry: The marine industry includes shipbuilding and marine engineering equipment, etc. Low NOx burners are used in the marine industry to reduce the generation of nitrogen oxides during combustion.
• The food industry: In the food industry, low NOx burners are also used. For example, in food processing factories, low NOx burners can be used in ovens, stoves, etc. Equipment.
• The petrochemical industry: Low NOx burners play an essential role in reducing nitrogen oxides' environmental pollution and combustion efficiency in the petrochemical industry. For example, low NOx burners are used in refineries, oil refining, and chemical production.
• Textile and chemical fiber industry: In the textile and chemical fiber industries, low NOx burners can be used in production and processing equipment such as looms, dyeing, and finishing. Using low NOx burners can help these industries improve products' quality and comply with relevant environmental standards.

How to choose low nox burners

When it comes to selecting a low NOx burner for a specific project or application, several key factors must be considered. The comprehensive analysis of these factors aids in making an informed decision.

• Emission Requirements

  Understanding the specific emission requirements is crucial. Determine the allowable NOx emission levels and ensure that the chosen low NOx burner complies with local, regional, or national environmental regulations.

• Fuel Type and Availability

  Consider the suitable fuels for the burner and their availability. Assess if the site can provide natural gas, oil, biofuels, or other options. Choose a low NOx burner designed for the specific fuel to ensure efficient combustion and emission control.

• Operational Requirements

  Consider operational requirements such as load range, duty cycle, and operating pressure and temperature. Select a low NOx burner capable of handling the specific operating conditions to maintain performance and control emissions effectively.

• Cooling

  Evaluate the cooling options. Passive cooling relies on the heat sink effect of the primary combustion zone, while active cooling employs forced convection or water-cooled jackets. Choose the appropriate cooling method based on the burner's thermal management needs and the system's design constraints.

• Combustion System Design

  Consider the specific design of the low NOx burner. Select a design that meets operational and emission control needs, ensuring proper air-fuel mixing, stable combustion, and optimal thermal performance.

• Technology Advancement

  When selecting a low NOx burner, it's essential to consider advanced technologies that can further reduce NOx emissions, such as Selective Catalytic Reduction (SCR) or Integrated Gasification Combined Cycle (IGCC) systems. Depending on the project's goals, budget, and feasibility, these technologies may be viable or beneficial options to consider.

Low NOx burners Q & A

Q: Can low NOx burners be used with any type of furnace?

A: Low NOx burner can be used with most types combustors and furnaces. But they are typically coupled with equipment designed to minimize emissions, like scrubbers or diluted baghouses, to meet stringent environmental regulations.

Q: How much low NOx burners reducing is possible?

A: The extent of reduction attainable with low NOx burners depends on several factors, including the initial NOx emission levels, the type and design of the low NOx burner employed, and the combustion adjustment and control technologies used in conjunction with the burner.

Q: Do low NOx burners require special maintenance?

A: While low NOx burners are not typically requiring special maintenance, they may demand more routine after the performance is checked, and some parts are replaced to ensure optimal functionality and emissions compliance.

Q: Can low NOx burners be converted to ultra-low NOx?

A: In some cases, it may be possible to upgrade or convert low NOx burners to ultra-low NOx burners, which typically use additional air staging or external fuel staging to reduce NOx emissions further. Consult with a combustion specialist to evaluate the feasibility of such a conversion for a specific burner and application.