Fuel Moisture is the most important of all fuel factors. Enough heat must be present to drive off all the moisture in the fuel. If a lot of moisture is present, much of the heat energy is used in converting the moisture to steam.
Consequently, the combustion process lacks intensity. More smoke will be produced because more of the fuel will be consumed during the residual phase. Uses a lot of energy driving out the moisture Less intense fire--less heat left for the combustion process Higher concentration of particulates due to less intense fire Shorter flaming phase and more residual phase More smoke and not lifted as high B. Low Moisture Content. Less energy used Reaches ignition temperature quicker More intense fire Longer flaming phase Less particulates Less smoke Shape The shape of fuel has a decided effect on the combustion process.
Flat-shaped fuel has a high surface-to-volume ratio. This allows the moisture in the fuel to escape more rapidly. Consequently, the fuel will be drier. It will ignite and burn readily, producing a minimal amount of smoke since a larger percentage of the fuel will be consumed during the flaming phase. Round fuel has a lower surface-to-volume ratio.
A larger percentage of the fuel will be consumed during the residual phase, producing more smoke than flat-shaped fuel. The size of fuel affects burning intensity and smoke production in much the same way as shape. Small fuel has a higher surface-to-volume ratio than larger fuel that allows the moisture to escape more rapidly and results in being drier than large fuel under the same conditions. Arrangement of fuel affects smoke production by changing both the rate of drying and the availability of oxygen required for the combustion process.
Compacted fuel dries out slowly and results in a wetter fuel. The result is a low intensity fire with most of the fuel being consumed during the residual phase. Coke is coal that has been heated in the absence of oxygen to drive off the organics. The smoke that this process produces is actually very valuable -- it contains coal tar, coal gas, alcohols, formaldehyde and ammonia, among other things. And all of these compounds can be distilled out of the smoke for use.
You may have heard of methanol a form of alcohol referred to as " wood alcohol. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. The smoke also contains carbon the main component of the wood , water vapour, and minerals that existed in the tree's cells such as calcium , potassium , and magnesium.
Since these minerals do not burn, they make up the ash that is also produced. Any other substances, such as plastics, that are burned introduce hazardous chemicals to the smoke that depend strongly on the composition of the substance itself. Smoke from cigarettes is much more complex in its composition, and often carcinogenic. It can include chemical components such as carbon monoxide , hydrogen cyanide, nitrogen oxides , formaldehyde, benzene , nicotine, and polycyclic aromatic hydrocarbons.
Exposure to different types of smoke can result in different health effects. Mild exposure to smoke from forest fires or a campfire is generally not extraordinarily harmful to health, whereas exposure to secondhand smoke from a cigarette is more harmful. General smoke from wildfires and other wood-based fires can make it difficult to breathe, and exposure to it can aggravate existing heart and lung conditions.
Symptoms of smoke exposure can cause sore eyes, tears, cough, and a runny nose. The carbon combines with oxygen to produce carbon dioxide until all that is left at the end of the fire is the ash — the minerals. Smoke inhalation is the primary cause of death in victims of indoor fires.
Depending on the house contents, the smoke generated can be extremely toxic or irritating. For example, burning plastics often produce soot and poisonous gases like carbon monoxide and hydrogen chloride. Another danger is that smoke contains flammable compounds. With increased oxygen, these can ignite either through open flames or by their own temperature. This leads to a backdraught or flashover effect. Smoke also obscures visibility. This makes it difficult to evacuate from a fire.
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