Sampling of acid mist in air and exhaust gas

A large part of our country belongs to the acid rain area, acid rain is formed by the formation of a large number of acidic gases emitted into the air to form acid fog, generally from the combustion of fuels, industrial production emissions and automobile exhaust emissions, the main acid fog of sulfuric acid fog, hydrochloric acid fog and nitrogen oxides, and some of the rarer chromic acid fog, hydrogen fluoride, hydrogen cyanide and organic acids.

In order to control the expansion of the area of acid rain caused by increased environmental pollution, the need to control the emission of acid mist from the source, the following is a brief description of the sampling method of acid mist commonly emitted by industrial enterprises.

Prerequisite: organized exhaust sampling conditions to meet the GB/T16157-1996 and HJ/T397-2007; unorganized exhaust sampling conditions to meet the HJ/T55-2000, ambient air sampling conditions to meet the HJ194-2017.

Sulfuric acid mist. Organized emissions of sulfuric acid mist sampling cartridge into the sampler head of the cartridge clip, in the soot sampler after the series of two inside the absorption liquid absorption bottles, collection of sulfur trioxide gas and penetration of the cartridge of the tiny droplets, and then connected with the empty bottle and the dryer, the connection tube should be as short as possible, the sampler into the exhaust cylinder sampling section for isotropic sampling, the sampling process, the nozzle heating temperature is not lower than the temperature of the flue gas. Sulfuric acid mist sampling in the unorganized emissions and ambient air with quartz fiber filter membrane, to 100 liters / minute flow rate to collect samples.

Hydrochloric acid mist. Organized hydrochloric acid fog sampling in series with two absorption bottles equipped with absorbent liquid, in accordance with the gaseous pollutant collection method, to 0.5 l / min ~ 1.0 l / min flow rate sampling, in the sampling process, the sampling pipe should be maintained to keep the temperature of the thermal insulation jacket for the 120 ℃, in order to avoid condensation of water vapor in the absorption bottle before the condensation. If the exhaust contains particles of chloride, should be installed in the absorption bottle before the film clip; when the humidity in the exhaust gas is large, hydrogen chloride and mainly in the form of hydrochloric acid mist hygroscopicity, this time in the dust sampler connected to the heating device (containing a shunt valve and filter membrane jacket), and series two bottles with absorbent liquid, in accordance with the sampling method of particulate matter collection of hydrochloric acid mist. The sampling process maintains the temperature of the soot sampling tube and the heating device at 120℃, and through the diverter valve, the sampling flow of hydrogen chloride gas is controlled at 0.5 liter/minute~1.0 liter/minute for sampling. When sampling the hydrochloric acid mist in the unorganized emission and ambient air, the front end is installed with a filter film clip, and two absorption bottles with absorption liquid are connected in series with the air sampler. The sample is collected at a sampling flow rate of 0.5 liter/minute to 1.0 liter/minute.

Hydrogen Fluoride. Organized hydrogen fluoride sampling in series with two absorption bottles equipped with absorbent liquid, in accordance with the collection of gaseous pollutants, sampling at a flow rate of 0.5 liters / min ~ 1.0 liters / min, in the sampling process, should maintain the sampling pipe insulation jacket temperature of 120 ℃, in order to avoid condensation of water vapor in the absorption bottle before the condensation. When the humidity in the exhaust gas is large, hydrogen chloride absorbs moisture and exists mainly in the form of droplets, hydrogen fluoride is collected according to the sampling method of particulate matter. The sampling process maintains the temperature of the soot sampling tube and the heating device above 120°C. Through the diverter valve, the sampling flow of hydrogen fluoride gas is controlled at 0.5 l/min~1.0 l/min, and the sampling is carried out. Sampling of hydrogen fluoride in unorganized emissions and ambient air, the relevant sampling methods have not been released for the time being.

Chromic acid mist. Organized emissions of chromic acid mist sampling cartridge into the sampler head of the cartridge clip, the sampler into the exhaust cylinder sampling section for isokinetic sampling. Unorganized emissions and ambient air sampling of chromic acid mist will be equipped with an absorbent liquid absorption bottle, connected to the air sampler, with a sampling flow of 0.5 liters / minute, the collection of samples.

Hydrogen cyanide. Organized hydrogen cyanide sampling in series with two absorption bottles containing absorbent liquid, in accordance with the gaseous pollutant collection method, with a flow rate of 0.5 l / min sampling. Unorganized emissions and ambient air sampling of hydrogen cyanide will be equipped with absorbent liquid absorption vials, connected to the air sampler, with a sampling flow of 0.5 l / min, the collection of samples.

Organized exhaust sampling, record the site conditions, exhaust related parameters; unorganized exhaust sampling, record the site conditions, environmental conditions; ambient air sampling, record the site environmental parameters.