1.燃烧器的组成
一个完整的燃烧器通常包括燃料喷嘴、配风器和燃烧道三部分。
燃料喷嘴是供给燃料并使燃料完成燃烧前准备的部件。燃料油喷嘴的主要任务是使燃料油雾化并形成便于与空气混合的雾化炬。外混式燃料气喷嘴将燃料气分散成细流,并以恰当的角度导入燃烧道,以便与空气良好混合。预混式燃料气喷嘴则使将燃料气和空气均匀混合后供给燃烧的。
配风器的作用是使燃烧空气与燃料良好混合并形成稳定而符合要求的火焰形状。特别是在烧燃料油的情况下,为了保证重质燃料油燃烧良好,除了使之良好雾化外,还必须有良好的配风器,使空气和迅速、完善的混合。尤其是在火焰根部必须保证有足够的空气供应,以避免燃料油受热时因缺氧而裂解,产生黑烟。
燃烧道也称火道,其作用有三:燃烧道耐火材料蓄积的热量为火焰的根部提供了热源,加速燃料油的蒸发和着火,有利于形成稳定的燃烧,这一点对炉膛温度较低的管式炉尤为重要。其次是它能约束空气,迫使其与燃料混合而不致散溢。第三是与配风器一起使气流形成理想的流型。
2.燃烧器的技术性能
(1)在炉型结构、物料物性、燃烧器台数相同时,管式加热炉辐射室的传热量随火焰高度的降低而增加。辐射室传热量增加,对流室传热量必定下降。由于辐射室炉管平均表面热强度是对流室炉管平均表面热强度的2倍,辐射室传热量增加和对流室传热量下降必然使得全炉炉管平均表面热强度提高。
(2)对强制供风的燃烧器,除非有特殊的高空气压降要求和备用风机的条件,否则必须同时在自然通风的条件下满足加热炉正常负荷的要求,即在设计燃烧器时,必须首先考虑自然供风的条件。
(3)燃烧器的安全操作是非常重要的,在以人为本安全生产越来越重要的今天,每台燃烧器设置长明灯成为必需。长明灯的燃料气管线必须是单独的,且压力稳定不受主瓦斯调节的影响。
a.负压炉,燃烧器的长明灯必须用自吸式供风,且风量可以调节。
b.正压炉,燃烧器长明灯必须有单独的、稳定的供风源(如仪表风),并且有压力显示。另外长明灯很不错加装自动点火装置。
中译英:
1 The burner
A complete burner generally includes a fuel nozzle, an air distribution device and a three portion of combustion.
Fuel nozzle is supplied to the fuel and the fuel complete combustion before preparation of components. Fuel oil nozzle of the main task is to make the fuel oil atomization and formed to be mixed with air spray torch. External mixing type fuel gas nozzle fuel gas is dispersed into small streams, and in the right perspective into combustion, so that with good air mixing. Premixed fuel gas nozzle makes the fuel gas and the air are uniformly mixed to supply combustion.
Air distribution device that is the role of the combustion air and fuel mixture and the formation of good stable and meet the requirements of the flame shape. Especially in the case of burning fuel oil, heavy fuel oil combustion in order to ensure the good, but the good atomization, must also have good air distribution device, so that the air and rapid, sound mixing. Especially in the flame root must ensure that sufficient air supply, in order to avoid fuel oil when heated due to hypoxia and cracking, black smoke.
Also known as fire burning channel, its role has three: burning channel refractory material accumulation heat as the root of the flame provides a source of heat, accelerating fuel oil evaporation and ignition, conducive to the formation of stable combustion, a low temperature of the furnace tube furnace is very important. The second is that it can restrain the air, forcing it to mix with fuel and not casual overflow. Third and an air distribution device with airflow to form a desired pattern.
2 Burner technology performance
(1) in the furnace structure, material properties, the number of the same burner, tubular heating furnace heat transfer with the flame height decreases. Radiation chamber heat convection chamber increases, heat transfer will decrease. Due to the radiation chamber furnace tube average heat intensity of the surface of convection chamber of furnace tube is2 times of the average heat intensity of the surface of the radiation chamber, heat convection and heat transfer increases the inevitable decline makes the furnace tube surface heat intensity increase average.
(2) the forced air supply to the burner, unless there is a specific air pressure drop and standby fan condition, otherwise must at the same time in natural ventilation conditions to meet the heating furnace normal load requirements, namely in the design of burner, must first consider the natural air supply conditions.
(3) the burner operation safety is very important, in a people-oriented safety is increasingly important today, each burner is arranged lamp become necessary. Pilot lamp fuel line must be a single, high and stable pressure gas regulating effect.
a Vacuum furnace, burner burning lamps must use self suction air supply, and air volume can be adjusted.
b Positive pressure furnace, burner lamp must have a separate, stable supply source(such as instrument air), and the pressure display. Another pilot lamp preferably with automatic ignition device.
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