Why does the biomass-fired boiler smoke in operation?
Question details (performance):
Black smoke happens during operating.
Answer: Fault reason:
(1) Insufficient air volume, improper air distribution, low furnace temperature: boiler usually equipped with air preheater, but when the air preheater has leakage, hot air flow doesn't satisfy the need of burning, smoke will happen.
(2) In the case of stalling situation in full automatic oil-fired boiler: significant increase of furnace negative pressure, no flame can be seen from the inspection hole, steam pressure and steam temperature drop, the steam flow decreases sharply. The water level drops suddenly and then rises sharply.
(3) Incomplete fuel burning: this is the main cause of boiler smoke, in the operation, some combustible gases such as carbon monoxide, hydrogen, methane will be generated in addition to carbon dioxide, sulphur dioxide, water vapor and oxygen, nitrogen, etc. during incomplete combustion. They burn and generate black smoke. Incomplete combustion of fuel will not only lead to black smoke, but also increase the use of fuel, increasing the operating cost of enterprises.
(4) Bad atomization effect of fuel oil and secondary combustion of gas duct: especially when high viscosity residue is burned, black smoke will come out of the boiler due to bad atomization effect.
Troubleshooting:
(1) Timely and appropriately feed into the root air inlet, adjust the primary and secondary air, mix oil mist and air correctly, and prevent hypoxia.
(2) Avoid excessive discharge, leading to insufficient oxygen intake and insufficient combustion.
(3) Ensure that oil supply, oil return pressure and fuel viscosity index are correct in boiler operation.
(4) Try to raise the temperature of air and furnace.
-
SZL series biomass-fired steam boilerLive Chat6-35 t/h1-2.5 MPa
-
DZL series biomass-fired steam boilerLive Chat2-10 t/h1-2.5 MPa
-
DHL series biomass-fired steam boilerLive Chat20-75 t/h1.25-5.4 MPa
-
Email us
-
WhatsApp: +86 18861589035
WeChat: +86 13506150756
Live Chat

-
In modern manufacturing, 6S workplace management has become an important method for enhancing shop-floor management and is being widely adopted by more and more enterprises. ZOZEN Boiler actively practices the 6S philosophy. By optimizing the workshop environment and management processes, the company has effectively improved production efficiency and product quality. ZOZEN Boiler 6S management — workshop neat and orderly Sorting and Set-in-Order: The foundation of efficient operationsI...02 Dec 2025 -
In Shandong’s coastal fishmeal corridor, the reliability of steam, fuel cost, and environmental performance are now core to plant economics.Seasonal catch cycles, volatile gas prices and supply elasticity, plus tightening environmental standards, are pushing producers toward biomass boiler retrofits. With proven experience in seafood processing and mature biomass solutions, ZOZEN Boiler has become a preferred partner for Shandong fishmeal plants. Why steam is the lifeline From Rongchen...25 Nov 2025 -
As the global energy mix shifts and low-carbon transitions accelerate, more industrial enterprises are turning to renewable-energy boilers. As a key player in China’s industrial boiler sector, Wuxi ZOZEN Boiler Co., Ltd. (hereinafter, “ZOZEN Boiler”) has continued to advance biomass boiler technology. The SZL series, in particular, has been deployed across a variety of industry scenarios domestically and internationally, building a strong track record of project experience. ...18 Nov 2025











