How to solve the problem of easy coking when burning pine wood?
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This post was last edited by kareale88 on 2019-3-6 at 17:36. How to solve the problem of easy coking when burning pine wood? bg4.png Pine contains a large amount of resin; will biomass pellets made from burned pine be prone to coking? How to solve this problem? The company’s boilers are grate-type boilers. Since there is a large supply of pine-based biomass pellets available in the vicinity at low prices, we are considering using them; however, we are concerned about coking during combustion, so we seek everyone’s help.
Bioparticle fuel has a low ash melting point due to the high content of elements such as potassium, sodium, and silicon. If the fuel contains too much moisture, the water vapor generated during combustion will soften potassium (as potassium is the main component of ash), and over time, heating this potassium leads to coking. The formed clumps are usually glassy in nature, similar to glazed tiles; they become very hard after cooling, making them difficult to remove manually. Coking not only affects heat transfer in the boiler’s heating surfaces, but the coke deposits and ash buildup also block the flue gas passages, increasing the flow velocity of the flue gas and creating flue gas channels that further accelerate wear on the heating surfaces, thereby disrupting normal production operations. (1) Choose to add a coking inhibitor to increase the ash melting point in order to suppress the occurrence of coking ； (2) Select an appropriate air distribution ratio; by reasonably adjusting the opening degrees of the control valves for the primary and secondary air streams, as well as the amount of oxygen supplied, it is possible to ensure that the key parameters are within acceptable ranges and that the flue gas temperature at the furnace outlet remains below the ash melting point of coal. This helps to maintain the quality of the steam, thereby preventing coking at the furnace outlet, reducing the blower pressure, and enhancing the boiler’s exhaust flow to further decrease the degree of coking ； (3) Select an appropriate furnace exit temperature to conduct optimization and combustion adjustment tests on the boiler; monitor the flue gas temperature at the furnace exit (or the wall temperature of the high-temperature heating surfaces) in real time, and establish an online optimization operation guidance system while ensuring that the key parameters remain within acceptable ranges ； (4) Ensure good mixing of air and fuel, avoid the formation of a reducing atmosphere near the water wall, and prevent severe local ash accumulation and coking. (5) Apply various operational measures to maintain stable temperature inside the furnace.
Carbon molecule vaporization combustion technology can solve these problems, and its environmental emissions are better than those of conventional direct combustion.
Scots pine and red pine are better