Isokinetic sampling device for particle mercury and gaseous mercury from stationary pollution source and isokinetic sampling method

Abstract

The invention discloses a sampling device for particle mercury and gaseous mercury from a stationary pollution source and a sampling method. The device comprises a sampling nozzle, a sampling gun, a cyclone separator, an ash hopper, a fine particle filter, a gaseous mercury sampling pipe, refrigerators, dryers, flow controllers, activated carbon mercury removers, vacuum pumps and cumulative volume meters, which are connected in sequence, wherein the sampling gun is arranged in a heating sleeve; the cyclone separator, the fine particle filter and an activated carbon adsorption pipe are arranged in an incubator. The invention also discloses the sampling method of the device. The sampling device and the sampling method, disclosed by the invention, have the following advantages: firstly, a particle mercury sample and a gaseous mercury sample are simultaneously collected; secondly, a sampling process is insulated, so that mercury loss and mercury speciation transformation are prevented, and further sampling representativeness is improved; thirdly, by two-stage dust removal of the cyclone separator and the fine particle filter, the sampling representativeness in a high dust-containing environment is guaranteed; fourthly, isokinetic sampling is guaranteed by the volume flow controllers; fifthly, by the postposed activated carbon mercury removers, residual mercury is prevented from being exhausted into atmosphere.

Description

technical field [0001] The invention relates to a gas sampling device, belonging to the field of environmental monitoring, in particular to a constant-speed sampling device and a sampling method for particulate mercury and gaseous mercury used for fixed pollution sources. Background technique [0002] Mercury emissions from stationary pollution sources have a huge impact on the environment and directly threaten human health. There is an urgent need to study the concentration and composition of mercury emissions from stationary pollution sources. my country's stationary pollution sources of particulate mercury and gaseous mercury sampling equipment mainly rely on imports. At present, the internationally recognized sampling methods mainly include the 30B method of the US EPA and the Ontario method of the US ASTM. The two methods have their own characteristics, and there are some shortcomings at the same time. . [0003] 1. The EPA30B activated carbon adsorption sampling method...

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Problems solved by technology

[0003] 1. EPA30B activated carbon adsorption sampling method is only used to collect gaseous mercury and cannot collect particulate mercury

[0004] 2. EPA30B activated carbon adsorption sampling method is suitable for sampling in low-temperature environments. High temperatures can easily lead to the release of adsorbed mercury, resulting in sampling errors

[0005] 3. EPA30B activated carbon adsorption sampling method, the adsorption tube is placed on the top of the sampling gun. In the environment with high dust content of fixed pollution sources, the adsorption tube will be blocked. This method cannot be used for sampling in high dust environments

[0006] 4. The Ontario sampling method belongs to the wet chemical absorption method, and the on-site sampling operation requirements are cumbersome, the cleaning of glassware is complicated, and the possibility of introducing errors is large

High air tightness requirements, air leakage is prone to liquid sucking back, resulting in sampling failure

[0007] 5. The digestion process of the chemical absorption liquid in the Ontario sampling method is cumbersome, and the impurity of the reagent will affect the detection of low-concentration mercury (100ng / l). It is necessary to adjust the redox property of the absorption liquid in time, otherwise it will easily lead to the loss of divalent mercury in the absorption liquid and affect the sampling. representative

[0008] 6. The Ontario sampling method requires that the sulfur dioxide in the stationary source is lower than the limit value. High sulfur dioxide content will lead to changes in the valence state of mercury in the absorption solution, affecting the analysis results and resulting in sampling failure.

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