What is the maximum allowable exhaust temperature for a boiler? (Recommended)

It seems that, under the current circumstances, there are no specific restrictions on the exhaust temperature of the boiler; it’s only when the exhaust temperature is too high that it affects the thermal efficiency of the heating furnace. You should take action in this regard. There are many existing techniques aimed at addressing high exhaust temperatures, such as heating the preheated air, which is a good solution. You can also investigate the internal factors of the heating furnace, such as dust accumulation and scaling on the furnace tubes, which can lead to poor heat transfer and thus high exhaust temperatures

Check the ash accumulation on the economizer and furnace tubes; if the flue gas temperature is too high, it indicates a decrease in boiler efficiency. An excessive supply of air can also lead to an increase in the flue gas temperature.

There is no upper limit on the boiler’s exhaust gas temperature, but the higher the exhaust gas temperature, the greater the heat loss due to exhaust gases, and the lower the boiler’s thermal efficiency. Currently, it is required that newly designed boilers achieve an efficiency of over 90%; therefore, based on this efficiency requirement, it becomes possible to limit the boiler’s exhaust gas temperature

With a flue gas temperature of 250°C, I don’t think there’s any danger, but it’s extremely wasteful – the heat loss due to flue gases is very high. Ours is kept at 100°C. Additionally, if you use electric dust removal, the low specific resistance of the dust can lead to a decrease in dust removal efficiency; it’s best to lower the flue gas temperature for operation

A flue gas temperature of 250°C is indeed too high; this indicates that the heat exchange process of the flue gas within the boiler is too short, or that there is severe ash accumulation in the tube bundles, resulting in a decrease in thermal efficiency and wasted fuel. The temperature should generally be kept between 160–190°C. A too low flue gas temperature is also problematic: water vapor in the flue gas condenses when it reaches its dew point, and the sulfides present in the flue gas form acidic substances that can corrode the tubes at the rear of the boiler, as well as the flue ducts and the exhaust fans. Additionally, an excessively high flue gas temperature can also cause damage to the exhaust fans.

It is also necessary to check whether the smoke barriers or partitions inside the furnace have collapsed or been damaged.

For a 420t/h CFB boiler, it is 149°C; too high a value represents a waste of energy, while too low a value may lead to corrosion due to low turbidity

It is indeed a bit high, but it depends on the situation. For example, in waste incineration waste heat boilers, the temperature at the flue gas outlet of such boilers must be kept above 500 degrees; otherwise, dioxins will be generated!

Is there one with a smoke exhaust temperature of 100 degrees? ? What are the components of the smoke? It is generally not lower than the dew point temperature of the acid~~~ Of course, with condensing boilers, this temperature can be reduced to 70 degrees; there are products in South Korea that utilize this technology!

There is no upper limit on the boiler’s flue gas temperature; however, the higher the flue gas temperature, the greater the heat loss due to flue gases, and the lower the boiler’s thermal efficiency. It is generally between 160-190°C.

Our 35T fluidized bed exhaust temperature is around 105 degrees; it should be possible.

Currently, there are no specific restrictions on the exhaust temperature of boilers; it is only when this temperature is too high that it affects the thermal efficiency of the heating furnace. Existing technologies can be used to control high exhaust temperatures, such as by heating the preheated air. There is also dust accumulation and scaling on the furnace tubes, which impairs heat transfer and leads to excessively high flue gas temperatures. However, the normal temperature is generally kept between 160–190°C; too low a flue gas temperature is also not desirable, as the water vapor in the flue gas condenses when it reaches its dew point, and the sulfides present in the flue gas form acidic substances that can corrode the tubes at the back of the boiler, as well as the flue ducts and exhaust fans. Additionally, excessively high flue gas temperatures can cause damage to other components as well. .

Quick-install fuel and gas stoves generally have a smoke exhaust temperature between 200 and 250 degrees

In fact, the lower the flue gas temperature, the better, but acid corrosion must be taken into account. The flue gas temperatures of several boilers I’ve come into contact with recently are 138, 144, and 146 (Harbin Boiler, 670t/h); provided for reference only.

The flue gas temperature of the boiler only needs to be above the dew point; if it is too high, heat loss from the flue gas increases, which has a significant impact on the boiler’s efficiency

A flue gas temperature of 250 degrees is a bit high; on one hand, it affects the thermal efficiency of the boiler, and on the other hand, it has an impact on the exhaust gas system. This is especially true for electrostatic precipitators, as high temperatures reduce the efficiency of dust removal and can also cause the plates to deform. We generally keep the temperature below 180 degrees. Last edited by mingyanping on 2008-2-22 08:47.]

Excessively high exhaust gas temperatures may affect the lifespan of the dust collector or exhaust fan

Could you elaborate on how high temperatures affect dust removal efficiency, for example, in the case of CaO, Al2O3, or Na2O, K2O, etc.? Regarding the issue of plate deformation, could we consider reducing the impact by adjusting the needle insertion angle? For example: using “sound waves”? I’d like to hear the details. Of course, there are mechanical methods as well, but they require a lot of simulations and calculations involving different time and space configurations; it also seems difficult to ensure that such methods remain effective over an extended period of time. Perhaps we could conduct R&D on HOT ESP technology. This post was last edited by wwyyhbmt on 2008-2-24 02:16.]

Indeed, a bypass can be installed, and various methods can be used to utilize the waste heat.

“What is the maximum allowable exhaust temperature for a boiler? ” I think there might be a limit, but it depends on the temperature of the flue gases (including hot dust, sparks, etc.) that can be discharged from the furnace, as well as the safety control \"margin\" or \"range\" or \"degree\" allowed by the boiler. There is no absolute value; I wonder if any expert can provide some reference range parameters. [This post was last edited by wwyyhbmt on 2008-2-24 02:20]