Any burning appliance is designed according to a certain gas composition. When the composition of the gas changes, resulting in changes in its calorific value, density and combustion characteristics, combustion conditions such as the thermal load, combustion stability, flame structure, and content of harmful components in the flue gas of the burner will change.
Suppose a certain burning appliance is designed based on A gas, and for some reason it is necessary to replace A gas with S gas. If the burner can ensure the normal operation of the burning appliance without any adjustment at this time, it means that S gas can replace A gas. , or it is said that S gas is "interchangeable" for A gas. A gas is called "base gas" and S gas is called "replacement gas". However, interchangeability is not always reversible. That is, S gas can replace A gas, but it does not mean that A gas can definitely replace S gas.
According to the requirements of gas interchangeability, when the nature of the gas supplied to users changes, the replacement gas must be interchangeable with the reference gas, otherwise users cannot be guaranteed to use gas safely and economically. It can be seen that gas interchangeability is a requirement for gas production units, which limits arbitrary changes in the properties of gas. In order to meet the interchangeability requirements, the gas production method cannot be selected arbitrarily, but from the perspective of ensuring the safety, reliability and economy of the entire gas supply system, this is completely reasonable and necessary.
Whether the two gases are interchangeable is not only determined by the properties of the gas itself, but also closely related to the performance of the burner and other components. Generally speaking, burners can adapt to certain changes in gas composition even without any adjustments.
The so-called adaptability of burning appliances refers to the ability of burning appliances to adapt to changes in gas properties. The main factor that determines the adaptability of a burning appliance is the performance of the burner, but other properties of the burning appliance (for example, the supply of secondary air, open combustion or closed combustion, etc.) also affect its adaptability. Therefore, the adaptability usually mentioned should be understood as the adaptability of the burning appliance, not just the adaptability of the burner.
It is of great technical and economic significance to study the issues of gas interchangeability and gas appliance adaptability. It puts forward requirements for the gas production department and the burning appliance manufacturing department at the same time from the perspective of expanding the use of various gas sources to the greatest extent. For burning appliance manufacturers, they should first strive to improve the process efficiency, thermal efficiency and hygienic indicators of various burning appliances, but at the same time they must pay attention to expanding the adaptability of burning appliances. In order to achieve this, sometimes it is even necessary to "sacrifice" some other benefits. However, the reasonable "sacrifice" is worth it, and it can be compensated by improving the economy of gas production. When designing and adjusting burning appliances, in addition to taking the reference gas as the main target, the possible replacement gas should also be estimated in advance so that targeted measures can be taken to expand the adaptability of the burning appliances.
Generally speaking, industrial burning appliances have lower requirements for gas interchangeability. When considering gas interchangeability, the main consideration should be to consider that gas can be interchanged with civilian burning appliances. Injection-type atmospheric burners are widely used for civilian burning appliances. Therefore, the study of gas interchangeability is mainly to study the interchangeability of gas in civilian burning appliances equipped with injection-type atmospheric burners.