Types of Industrial Gas Burners in India and Combustion Systems

When buying new equipment or upgrading ageing furnaces and ovens, the heat treater frequently has options for Industrial Gas Burners in India and combustion systems. Despite the fact that natural gas costs are currently quite competitive, it is important to match the heating and temperature uniformity requirements of the applications with the best and most economical systems. Let's find out more.

Introduction: Gas Burner Types

The Gas Burners can receive air for combustion in a number of different ways. The word "primary air" refers to air that is provided and combined with fuel before ignition. All combustion air is combined with the fuel and is ready to ignite as soon as it reaches the burner nozzle in orifices and valves, which are typically used to manage this. Burners and combustion systems where the air and gas are mixed before the burner nozzle are referred to as "pre-mix" systems. A "nozzle-mix" system is one where they are blended at or within the burner nozzle.

Burners For Pre-Mix

There are many pre-mix systems, but they all require the fuel and air to be proportioned separately in order to produce an air/gas mixture that will burn efficiently at the burner nozzle. Prior to being piped to the burner nozzle, the volume flow of the air and gas needs to be controlled and mixed. They are combined using a mixing tool to create a highly flammable mixture.

Burners With Nozzle-Mix

In nozzle-mix burners, air and gas are combined at the burner nozzle. While some nozzle-mix burners combine some primary air before the point of ignition, others maintain the gas and air separate up to that point. Systems with sealed-nozzle mixed burners only use primary air. In contrast, secondary air is introduced at the burner and fed to the flame after it has been ignited. Atmospheric burners, which use roughly 70% primary air and 30% secondary air, are an example of both types.

Systems For Direct-Fired And Indirect-Fired Combustion

Direct-fired and indirect-fired systems in Gas Burner are the two broad types into which combustion systems can be separated. Direct-fired applications expose the work to the combustion byproducts, whereas indirect systems either fire into radiant tubes or find the work shielded from the flame by retorts and muffles, among other things. Secondary air is drawn into the furnace in the majority of direct-fired combustion systems (such as box furnaces) through leaky doors, other openings, and negative furnace pressure.

Many advantages are also offered by recuperative systems. Recuperators and regenerators are the two different categories of air preheaters (Fig. 1). Gas-to-gas heat exchangers called recuperators are installed on the furnace stack. While preventing the two streams from mingling, internal tubes or plates transfer heat from the exiting exhaust gas to the arriving combustion air. Recuperators come in a wide range of designs, flow rates, and temperature settings. Regenerators have a minimum of two distinct heat-storage portions. Each regenerator alternately receives combustion air and flue gases, heating the storage medium and then removing heat from it. A payback analysis is used to justify costs (Equation 1).

Sizing a Combustion System

To prevent overheating or underheating situations, which could harm the heat-treatment process, heat input and heat demand must balance. Burners will cycle more if they are used with an excessive heat output. In order to avoid cycle and even out temperature swings in the furnace, it is much preferable to have burner output more closely match the needed heat. Controlling the temperature during a cycle is a crucial process-control parameter.

Shock Cooling

The capability of swift temperature adjustments throughout any phase of the cycle is one advantage of using indirect heating via radiant tubes in furnaces (e.g., dropping from carburizing to hardening temperature prior to quenching). By stopping the fuel supply to the combustion system and enabling cool combustion air to pass through the tubes, this feature can be activated. To guarantee that burners properly relight following the cooling section, the furnace must be equipped with this capability.

Security and Controls

Anyone who uses or maintains burners or combustion systems must be aware of the fundamental operations of the numerous parts that come together to form the system's efficient and secure operation. Every component serves a crucial purpose. Others are solely safety devices that instantly shut the system down to prevent damage and injury, while some are for operation and control.

People are frequently a little intimidated when first viewing a combustion system due to the sheer number of valves, controllers, and other parts. This initial anxiety is normal because no one should operate a combustion system before being fully aware of all the parts, how they work, and how to operate it safely. Learning what each gadget is doing and how it is controlled for safe start-up, operation, and shutdown is also encouraged by having a healthy respect for it.

System surveillance to ensure safe operation

Layers of safety checks and equipment are present in combustion systems to safeguard operators and machinery. Other devices in the system are intended to back up a safety device in the event that it is not functioning properly. The usage of two primary gas shutoff valves in series is an illustration of this. The other is there to turn off the gas if there is a leak or failure of one. A different illustration involves typically closed valves (i.e. valves held open when power is applied). If there is a power outage, these valves will close on their own.

Safety Equipment

 

The flame monitor, which must be utilised in all combustion systems, is the first line of protection. The mechanism will cause the main gas valves to shut off if there is no flame at the burner.

A flame arrester is a second line of defence in pre-mix combustion systems. The flame will be extinguished at the flame arrester if the combustion were to spill back into the pre-mix supply line. According to NFPA 86, a "device that inhibits the transmission of a flame through a combustible gas/air mixture by quenching the flame on the surface of an array of small passageways where the flame must travel" is a flame arrester.

In Gas Burner an automatic fire check is a flame arrester fitted in a pre-mixed system that has a mechanism to put out the fire and turn off the fuel supply. An automated fire check makes use of a spring-loaded shutdown valve that is kept in place during normal operation by two bimetallic rods. The bimetallic rods will bend as a result of the heat from the flame and release the spring-loaded shutdown valve in the event of a flashback. At least twice a year should be set out for inspecting fire checks to make sure they are working properly.