Once biomass is burned, the main products are carbon monoxide and carbon dioxide.
Carbon monoxide molecules are unsaturated, metastable molecules that are chemically stable with respect to decomposition. At room temperature, carbon monoxide does not react with acids, alkalis, etc., but it can form an explosive mixture when mixed with air. It may cause combustion and explosion when exposed to open flames and high temperatures. gas. Since the valence of the element carbon in the carbon monoxide molecule is +2, it can be oxidized to +4, which is reducible, and it can be reduced to a low-valence state, which is oxidizing . Under certain conditions, carbon monoxide and water vapor react in equal moles to produce hydrogen and carbon dioxide: CO + H2O → H2 + CO2. In industrial devices, the early reactionThe displacement of carbon monoxide is generally carried out in two stages, namely the displacement at high (medium) temperature and the transition to low temperature. High (medium) temperature conversion uses series of iron as catalyst. The typical ratio of water vapor to carbon monoxide is about 3. Under the conditions of temperature 300-500 ℃ and space velocity 2,000-4,000 h-1, the content of carbon monoxide is about 3. the output of high temperature conversion furnace is 2%-5%; a high activity copper-zinc catalyst for low temperature movement, at a temperature of 180 to 280 °C and a space velocity of 2000 to 4000 h-1, the carbon monoxide content at the exit of the furnace at low temperature is 0.2%-0.5%, and carbon dioxide (carbon dioxide), a carbonaceous oxygen compound, the chemical formula is CO2, the weight of the chemical formula is 44.0095, c 'is a colorless and harmless productGolden. gas at normal temperature and pressure [2] or colorless and odorless gas with a slightly sour taste in its aqueous solution. Common greenhouse gases are also one of the components of air (accounting for 0.03% to 0.04% of the total). volume of the atmosphere [5]). In terms of physical properties, carbon dioxide has a melting point of -56.6°C and a boiling point of -78.5°C. It is denser than air (under standard conditions) and is soluble in water. In terms of chemical properties, carbon dioxide is chemically inactive and has high thermal stability (only 1.8% decomposes at 2000°C). It cannot burn and generally does not sustain combustion. It is an acidic oxide and has the properties of an acidic oxide. . Since it reacts with water to form carbonic acid, it is a carbonic acid anhydride.
Carbon dioxide can generally be produced by calcining limestone at high temperatureserature or by the reaction of limestone and diluted hydrochloric acid. It is mainly used in refrigeration of perishable foods (in solid state), as a refrigerant (in liquid state). , in the manufacture of carbonated carbonated drinks (gaseous state) and Solvent for homogeneous reaction (supercritical state), etc.