Complete extraction of gaseous pollutants CEMS routine maintenance precautions

Complete extraction of gaseous pollutants CEMS is mainly responsible for the concentration measurement of SO2 and NOx. It is a common CEMS measurement method for gaseous pollutants. According to whether the sample gas is dehumidified, it is divided into cold-dry method and thermal-wet method. According to the dehumidification location is divided into pre-treatment and post-treatment two ways.

As environmental protection laws, regulations, and related standards are increasingly improved and environmental protection is receiving increasing attention, failures in the course of daily operation and maintenance not only increase the amount of routine maintenance, but also affect economic benefits. Therefore, we must pay attention to routine maintenance. Then pay attention to the following points in daily maintenance:

First, the sampling probe

1. When the sampling probe is installed, it should have a downward inclination angle to avoid the accumulation of water at the probe and the probe to cause the SO2 measurement to be inaccurate. Therefore, attention should be paid to this problem during installation.

2. Whether it is a cold-dry method or a hot-wet method, the sampling probe needs to be heated to ensure that the moisture in the flue gas does not condense at the probe. Therefore, the heating temperature of the sampling probe must be paid attention to in routine maintenance. If the heating temperature does not meet the manufacturer's specified temperature, it will cause the water at the probe to cause the SO2 measurement to be low, and at the same time, it will easily lead to blockage of the probe.

3. The sampling probe has a built-in soot filter device (filter element). The filter device is generally made of porous ceramic or sintered stainless steel. It is necessary to check regularly to see if the filter device is clogged. If the filter device is clogged, the sample flow rate will be too low, which will affect the measurement accuracy of gaseous pollutants. If the filter device is often blocked, clean or replace it regularly, or change the frequency of backflushing.

4. The full extraction method from the probe to the sampling pump inlet is a negative pressure sampling, so pay attention to the sealing of the probe and the probe and the sampling line connector to prevent air from entering the measurement system, resulting in low SO2, NOx measurement, and increased oxygen (electrochemical or Paramagnetic oxygen when measuring oxygen)).

Second, the sampling pipeline

1. Because the full extraction method is a negative pressure sampling, it is imperative to attach importance to the sealing performance at the sampling line joint and prevent air from entering the sampling system.

2. Cold-drying post-treatment sampling method of gaseous pollutants CEMS, because the dehumidifier is generally installed in the station, so the entire sampling line is the whole process of heating (heat and humidity method also requires full heating), so we must always pay attention to sampling Pipeline heat tracing temperature, heating temperature >120Â°C.

3. When the sampling pipeline is laid, do not appear U-shaped bends to avoid inaccurate measurement due to accumulated water. If there is a U-bend, SO2 will be low in the measurement, but it will be normal after the blowback, and it will show a low value after a period of time.

4. The system-wide calibration tube in the sampling line should be fully connected.

Third, fine dust removal water

1. Before the sample gas enters the analysis, fine dust removal and dehumidification shall be carried out to filter out the fine particles and the moisture in the sample gas. Therefore, in the daily maintenance to observe the fine dust removal device (filter or filter), in accordance with the requirements of the CEMS manufacturers instructions for regular replacement, filter and filter is not recommended to clean but directly replace.

2, to pay attention to the condenser condensation temperature every day, to control at 2- 6 Â°C, can not be too high nor too low. If the condensing temperature is too low, condensate will freeze in the condenser, resulting in poor drainage and poor condensation. If the condensing temperature is too high, moisture will be generated in the sample gas, causing the analyzer to become contaminated and the measurement result inaccurate.

3. If Nafion tube is used as a dehumidification device, it is necessary to dehumidify the decontamination gas for the decontamination gas, and often pay attention to the treatment device of the decontamination gas to ensure that it is a dry decontamination gas.

Fourth, gaseous pollutant analyzer

1. The analyzer shall be calibrated (system-wide calibration) and verified according to the frequency specified in HJ 75-2017 standard.

2, replace the analyzer to re-commissioning and acceptance before they can be put into operation.

3. The analyzer shall perform system calibration according to the frequency specified in HJ 75-2017 standard to detect the indication error and response time.

4, in the daily calibration process, especially the calibration range, pay attention to the analyzer set the standard gas concentration and the actual standard gas concentration has been.

5. Regularly check the use date of standard gas. Expired standard gas or gas with pressure less than 2 MPa (personal advice) cannot be used for daily calibration.

Fifth, auxiliary system

1. Exhaust gas exhaust system: In the north of winter, due to the low temperature, in order to prevent the ice in the tail gas discharge pipeline, insulation measures should be taken during installation or operation (such as installation of thermal insulation cotton, installation of self-limited temperature-associated heating cables, etc.) ).

2. The condensate should be drained in time and dumped or discharged to the designated location according to the regulations. It cannot be dumped or discharged at will.

3. Regularly check the aging of the peristaltic pump tube. If the peristaltic pump tube ages, a small portion of the air will be squeezed into the condenser during peristaltic pump operation, resulting in periodic changes in the oxygen level in the CEMS system.

EN124 B125 C250 D400 BMC/Smc Manhole Cover and frame

Product description :

16 years experience on Manhole Cover manufacturing and exporting.

International R&D team for your wanted design.

SMC,BMC,ductile iron,grey iron material is available.

Model: B125, C250, D400, E600, F900.

Certiifcate: EN124, BVQI and AS3996.

Size: 200~1200mm in square, rectangle or triangle etc.

Bearing Class / Loading Capacity of Cast Iron Manhole Covers
Class	Apply to	Bearing	Remarks
EN124-A15	Areas where only passed by Pedestrians and Bicycles.	15KN
EN124-B125	Footways, parking lot or similar areas.	125KN	HOT-SELLING
EN124-C250	The edge combinative area of vehicle road and the pavement.	250KN
EN124-D400	Vehicle area and urban arterial road.	400KN	HOT-SELLING
EN124-E600	Shipping port and parking apron area.	600KN
EN124-F900	Airplane taxiway and huge dock.	900KN