![]() ![]() Cooling - After thermal decomposition is complete, the charred biomass needs to cool. ![]() If disturbed during this phase and air enters, combustion may take place. The cellulose, hemicellulose and lignin components of the dried-out biomass break down and carbonize. Thermal decomposition - Thermal decomposition starts between 260☌ and 300☌ (500☏ to 572☏).In the case of grains, storage moisture contents of 13% to 17% are reduced to near zero. Dehydration - Above 100☌ (212☏), the water trapped in the pores of the biomass is evaporating and driven off as hot vapor.It generally takes place in three phases: The process has been used for thousands of years for the conversion of wood into charcoal. It occurred to me that the process of grain self-heating and potentially smoldering, and at times igniting into an actual fire and burning, is rather similar to the charcoaling process.Ĭharcoaling is a so-called slow pyrolysis process of heating wood or organic material (that contain cellulose, hemicellulose and lignin components, all a form of starch that is a major constituent in corn and other grains) in the absence of oxygen and over a long reaction time (days). Once the carbonization process is complete, the mound or pit kilns are uncovered and the charcoal is allowed to cool. The kiln has to be tended constantly over the next several days, opening and closing holes in the soil layer to control the amount of air. Thus, the heat (energy) for the carbonization process is supplied by combusting part of the wood itself and controlling the amount of air into and exhaust out of the pile. Once a strong fire is going, air entry is controlled to enter on one side and exit on the other, causing the combustion region to gradually move through the pile. In both so-called mound and pit kilns, room is left at opposite ends for an air inlet and outlet, and the material is ignited on one end. Wood is either stacked in the shape of a beehive (or igloo) or packed in a dug-out soil pit and then covered with a layer of soil to create an airtight seal. Self-heating, thermal decomposition of stored grainĭuring my trips to Africa, it is common to see people gathering wood and making charcoal that they sell in large bags along the roadside. The science behind it has not been fully explored and documented, so there are many opinions and speculations circulating. We have covered many of these in this column over the years but before we review three key ones, let’s get a better understanding of what causes a fire to occur in stored grain. Best stored grain monitoring and management practices are the most effective ways to prevent grain fires. He said residents should be confident the fire department and BioUrja are getting the situation under control.A recent series of white papers by US-based Nationwide Mutual Insurance Co., with input from its Nationwide Grain Advisory Board, addressed pre- and post-fire grain issues and an initial response plan when fires erupt in stored grain. Sollberger said a third party will soon begin aerial monitoring of the area around the plant. "We don't feel we have an immediate danger, but that being said, the only way that they're going to take these silos down is whatever's burning inside of there has to be extinguished." "So something's burning in there," said Sollberger. Monday afternoon, while Washington Street remains open to normal traffic. The Cedar Street Bridge was shut down in both directions at approximately 3 p.m. The smell of smoke lingered in the area around MacArthur Highway and Washington streets, near the plant. The fire briefly resurged on Friday.Īs of Monday morning, dark gray smoke was still emanating from one of the damaged silos. Two people suffered non life-threatening injuries in the explosion. The explosion last Thursday night destroyed one silo and damaged three others. "But basically, either we have to pierce the side of the silo and inject water, or put water from the top and have it flow down the silo. We have a couple different options we're kicking around," said Sollberger. "We're trying to explore options right now. Peoria Interim Fire Chief Shawn Sollberger said extinguishing the remaining fire is tricky - and hazardous. Fire is still burning in a damaged silo at the BioUrja ethanol plant in South Peoria several days after a grain bin explosion damaged the complex. ![]()
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