Basic technical requirements for dual fuel burners
A dual fuel burner is a device that enters the furnace in a certain proportion, speed, and mixing method to achieve timely ignition, efficient, and clean combustion. This equipment has a fully automatic combustion device with automatic ignition, flame monitoring, and automatic adjustment devices. Currently, the majority of oil and gas burners used in industrial kilns in China are fully automatic burners.
Dual fuel burners are important equipment in oil and gas industrial furnaces. According to the combustion of fuel, it can be divided into oil burners and gas burners, as well as dual-purpose oil and gas burners that have the function of burning two types of fuels (fuel and gas or two different gases). Fuel burners mainly include injectors (atomizers), air conditioners, etc. Gas burners are mainly composed of gas nozzles or nozzles, regulators, etc.
In order to meet the requirements of the combustion process in the furnace, ensure the safety, reliability, efficiency, economy, and low pollution emissions of the equipment, the burner should have the following main technical performance:
(1) High combustion efficiency.
In order to ensure the combustion efficiency during high-speed operation, it is required that the fuel burner has a certain working range and good atomization effect. That is, after atomization by oil droplets, the size of oil droplets is uniform, the atomization angle is appropriate, the density distribution of oil mist along the circumference is consistent with the air distribution, and the mixing effect between oil mist and air is good.
At the rated gas pressure, the gas burner should be able to fully burn through the rated gas volume, achieving the rated heat load production.
(2) Reasonable air distribution ensures stable and sufficient fuel combustion.
The root of the atomization torch should be supplemented with an appropriate amount of air in a timely manner to prevent the decomposition of oil and gas into carbon black through high temperature and low oxygen conditions. A suitable size and position reflux zone should be formed at the combustion airflow outlet. The fuel and air should be placed in a higher temperature field to ensure fast and stable ignition. In the middle and later stages of combustion, the air and oil mist should be mixed quickly and evenly to ensure complete combustion, and harmful substances (CO, NO, etc.) produced in the combustion flue gas should be minimized as much as possible.
(3) The shape and length of the combustion flame should match the furnace, the flame should have good fullness, and the flame temperature and blackness should meet the requirements of the furnace. Do not allow flames to wash against the furnace walls, bottom, and outlet windows for convective heating.
(4) Good regulation performance. The burner should be able to meet the requirements of furnace load regulation, that is, between the minimum and maximum load of the furnace, the burner can work stably without tempering or misfire.
(5) The less energy the nozzle consumes during the atomization process, the better.
(6) The wind resistance of the air conditioning device is small, and the operating noise is low.
(7) The ignition, speed regulation and other operations are convenient, safe and reliable.
(8) Simple and compact structure, reliable operation, high degree of automation, and easy maintenance.
The combustion status of oil and gas boilers and furnaces mainly depends on the working performance of the burner. Poor atomization quality or unreasonable airflow distribution of oil burners can lead to the following adverse consequences:
(1) Incomplete combustion, pollution of the heating surface at the tail of the boiler, increased smoke temperature, and even secondary combustion.
(2) The heat loss of partially combustible gases increases.
(3) The heat loss during the combustion of flammable solids increases.
(4) Burner outlet or furnace coking.
(5) Accidents such as stalling, firing, or even furnace explosions occur.