Gaseous mercury sampling device for stationary pollution source

Abstract

The invention relates to a gas sampling device, belongs to the field of environmental monitoring, and particularly relates to a gaseous mercury sampling device for a stationary pollution source. The gaseous mercury sampling device for the stationary pollution source comprises a smoke pipe, a refrigerator, dryers, particulate matter filters, flow rate controllers, gas pumps and accumulative volume meters which are connected sequentially, wherein the tail part of the smoke pipe is provided with a temperature preservation box; a gas outlet of the refrigerator is connected with a gas discharge end of the smoke pipe by a heat tracing pipe. The gaseous mercury sampling device for the stationary pollution source has the following advantages: 1. the device is better in stability, heats up uniformly because of heat tracing of the smoke pipe in the whole process, and can prevent pipeline blocking; 2. the sampling quality is higher, a mode that a stainless steel coil pipe is cast by high-heat-capacity metal is adopted for the refrigerator, and moisture in flue gas can be removed well; 3. the sampling flow rate is more stable, and the special volume flow rate controllers can acquire wider sampling flow rate, so that air flow is more stable; 4. the sampling volume metering is more accurate, counting pulses are collected by a precise photoelectric encoder, and thus the metering precision of the sampling volume is improved substantially.

Description

technical field [0001] The invention relates to a gas sampling device, which belongs to the field of environmental monitoring, in particular to a gaseous mercury sampling device used for fixed pollution sources. Background technique [0002] Due to the impact of gaseous mercury emissions on the environment in China, my country urgently needs to understand factors such as the composition and emission concentration of gaseous mercury pollutants. Instruments mainly rely on imports, and imported instruments cannot meet the needs of my country's national conditions in many aspects, and there are the following problems: [0003] 1. The bong part includes the bong main body and the heating pipe part. Due to the high humidity of the flue gas, condensed water is generated inside the bong part and the pipe is blocked. At the same time, the bong part needs to be heated all the way and the temperature is between 120-150 degrees Celsius. Most of the existing bong parts are heated by AC 2...

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Problems solved by technology

[0002] Due to the impact of gaseous mercury emissions on the environment in China, my country urgently needs to understand factors such as the composition and emission concentration of gaseous mercury pollutants. Instruments mainly rely on imports, and imported instruments cannot meet the needs of my country's national conditions in many aspects, and there are the following problems:

Although the cooling effect of using a compressor is good, but the cost is high, the instrument is large in size, and it is not convenient to use on a higher sampling platform; the use of ordinary semiconductor refrigerators will not guarantee the cooling temperature of the refrigerator due to the high temperature of the flue gas; only use adsorption Activated carbon in the medium removes particulate matter, but the effect is not obvious for smaller diameter particles

[0005] 3. The main technical solution of the gas flow measurement and control part is to use a gas mass flow controller to measure and control the gas flow. In fact, due to the high moisture content of the flue gas of fixed pollutants in my country, it is difficult for the flue gas dehumidification part to control all The moisture is all removed, but the residual moisture in the flue gas enters the gas mass flow controller, which will reduce the measurement accuracy, and the long-term measurement may even cause damage to the sensor. It is necessary to find a more durable gas flow control method

[0006] 4. The air pump part is mainly based on the diaphragm vacuum pump, but due to the large gas resistance of the adsorption medium, the pumping flow of the air pump will be insufficient to meet the sampling requirements, and the pump membrane will be under high load for a long time after time sampling State and accelerate aging, reduce service life

[0007] 5. The gas volume measurement part mainly includes membrane flowmeters and gas flow accumulation methods. Some imported instruments use special membrane flowmeters for sampling volume measurement, but such special membrane flowmeters are difficult to import and expensive; domestic similar products The gas flow accumulation method is often used, that is, the gas sampling volume is obtained by multiplying the gas sampling flow rate by the sampling time length, but the gas volume measurement accuracy of this method is not high, and there are large errors, which directly affect the sampling results

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