———————————————◆ Exhaust gas analysis ◆———————————————
Formaldehyde waste gas composition
Formaldehyde, colorless aqueous solution or gas, with pungent odor. It can be mixed with water, ethanol, acetone and other organic solvents in any proportion. The liquid is easy to be turbid when it is stored for a long time when it is cold, and it will form trioxane precipitate when it is cold. Part of formaldehyde escapes during evaporation, but most of it becomes trioxane. The product is a strong reducing agent, and has stronger reducibility when it is slightly alkaline. It can be oxidized to formic acid slowly in air. Pure formaldehyde has strong reducing effect, especially in alkali solution. Formaldehyde itself can carry on condensation reaction slowly, and it is easy to polymerize.
———————————————◆ 废气系统设计 ◆———————————————
(1) after the dust and granular substances are removed by pretreatment, the waste gas is sent to the activated carbon adsorber I and II. When the activated carbon adsorber I is close to saturation, the treatment gas is automatically switched to the activated carbon adsorber II (the adsorption operation of the activated carbon adsorber I stops), and then the activated carbon adsorber I is desorbed and desorbed with hot gas flow to desorb the organic matters from the activated carbon. In the desorption process, the organic waste gas has been concentrated, and the concentration has increased dozens of times than before, reaching more than 2000 ppm. The concentrated waste gas is sent to the catalytic decomposition unit, and finally discharged as CO2 and H2O.
(2) after the desorption, the activated carbon adsorber I will enter the standby state. When the activated carbon adsorber II is close to saturation, the system will switch back automatically, and at the same time, the activated carbon adsorber II will be desorbed and desorbed, so it will work in cycle.
(3) when the concentration of organic waste gas reaches more than 2000 ppm, the catalytic bed can maintain spontaneous combustion without external heating. The scheme not only greatly saves energy consumption, but also reduces equipment investment because the treatment capacity of catalytic decomposer only needs 1 / 5 of the original waste gas treatment capacity (60000m3 / h). This scheme is not only suitable for continuous work, but also suitable for intermittent work.