The quality of the cartridge dust inspection results measured enormous impact

Category: Industry News Date: 2012-7-5 Source: www.cwlx.cn

In the monitoring of air pollution, monitoring of the concentration of dust emissions is a relatively routine monitoring of projects, but also a more mature monitoring factor, whether it is monitoring sampling sites, or monitoring equipment, have a clear quality control and management regulatory requirements. Among them, collecting dust sampling cartridge recommend using long Viagra CWSY glass fiber cartridge. Sampling cartridge sample preparation before the air and emission monitoring and analysis methods "(fourth edition), high temperature weight loss constant re-processing to do a clear requirement, dust filter after sampling only requires a constant weight. Cartridge after the sampling of the monitoring specifications in a 105 ℃ oven bake for 1 hour to reach the constant weight required, then the monitoring results is relatively large errors of up to 30 ~ 200mg/m3 the Main factors: First, the laboratory environment humidity, time of the desiccator; the impact of the flue gas humidity. Constant weight after sampling cartridge, remove the human weight loss caused to the cartridge, the other basically positive error. Ruled out in the monitoring of human factors, laboratory weighing error can not be ignored. In this study, laboratory quality control standard blank cartridge, to achieve satisfactory results;, but also improve the work efficiency.

 

1 Experimental

1.1 Experimental apparatus

analytical balance: AG104 electronic balance; oven thermostat: adjustable digital display incubators; cartridge: plastic cartridge.

1.2 experimental procedures

1.2.1 Sampling the preparation of the previous cartridge

checks and screening of

qualified cartridge, main Pinhole check, weight screening, resistance screening, weight loss treatment, these checks are described in the relevant literature.

qualified cartridge into the oven. Bake 1 hour at 500 ℃, eliminating the high temperature sample cartridge weightlessness. Constant temperature of 105 ~ 110 ℃, 2 hours after drying, into a dedicated cartridge, and then placed in a desiccator, cooled to room temperature, dryer and balance room set a humidity table control, repeated drying to constant weight, two adjacent weighing difference of no more than 0.0005g (hereinafter the same).

1.2.2 Standard Preparation of blank cartridge

from the above batch of prepared sample before the cartridge, the selection of the 10 weight basically the same cartridge, compiled a good analysis of the number, deionized water or distilled water, a little moist. Into the oven, under constant temperature of 105 ~ 110 ℃, drying, four hours later, into a dedicated cartridge weighing bottle, and then placed in a desiccator, cooled to room temperature, repeated drying to constant weight, the above operation standard weight as a standard blank cartridge; quality control in the process of drying, cooling, weighing the sample cartridge.

1.2.3 Sampling cartridge weighing

sampled cartridge with two standard blank cartridge into the oven, ionized or distilled water wet standard required to go blank cartridge, and visually, as close as possible after sampling cartridge content in the constant temperature of 105 ~ 110 ℃, 4 hours after drying, placed in a dedicated cartridge weighing bottle, and then placed in a desiccator, cooled to room temperature, repeated drying to constant weight. At this point, the standard blank cartridge weight and standard weight difference of ± 0.0005g weighing the results of these sampling cartridge is within the scope of quality control, reliable. Otherwise, these cartridges need constant weight process, until qualified.

 

2 Results and discussion

2.1 air humidity cartridge weight

laboratory analysis environment in

often limited by the objective conditions, if not a constant temperature and humidity chamber, the cartridge before sampling, sample after weighing, the humidity of the laboratory environment can not be around to keep consistency, this condition is often overlooked. Such a cartridge in the oven → drying → balance weighing process, the more time exposed to the air, the cartridge will absorb air moisture, the impact of constant weight. During the experiment dryer humidity 35%, balance 37% humidity, the two humidity error is negligible, the analysis results are shown in Table 1.

a different air humidity of the weighing results g

            

relative humidity

            
            

1

            
            

2

            
            

3

            
            

4

            
            

5

            
            

49%

            
            

16.3798

            
            

16.5363

            
            

16.4812

            
            

15.7865

            
            

15.8365

            
            

57%

            
            

16.3818

            
            

16.5385

            
            

16.4835

            
            

15.7889

            
            

15.8383

            
            

65%

            
            

16.3844

            
            

16.5418

            
            

16.4855

            
            

15.7913

            
            

15.8409

            
            

75%

            
            

16.3864

            
            

16.5443

            
            

16.1881

            
            

15.7934

            
            

15.8432

            
            

82%

            
            

16.3883

            
            

16.5457

            
            

16.4909

            
            

15.7955

            
            

15.8453

            
            

91%

            
            

16.3902

            
            

16.548

            
            

16.4933

            
            

15.7972

            
            

15.8481

            
            

99%

            
            

16.3929

            
            

16.5511

            
            

16.4959

            
            

15.8001

            
            

15.8514

            

seen from Table 1, with increasing relative humidity of the air, said value corresponding increase in Humidity for each additional 10% said the value of the average increase 23ng. According to specifications for each sample volume to reach at least 330 liters, then increase the value of the concentration of dust emissions to 69.7mg/m3.

2.2 length of cooling time on the weighing

The only clear the

monitoring and technical specifications of the cartridge out of the oven, placed in the desiccator to cool to room temperature after weighing no requirement to put the cold time. The tests showed that the cooling time and place the cartridge inside the dryer how much related to placement method. When the cartridge filled or filled with two-thirds of the dryer, the cartridge can not be within 30min to cool to room temperature. Only when the cartridge in the dryer, put a layer, 30min can basically meet the temperature cooled to room temperature in the dryer. But with the growth put the cold time, the cartridge weight also increases. Weighing the results in Table 2.

The determination results

table under two different cooling time g

            

storage time

            
            

1

            
            

2

            
            

3

            
            

4

            
            

5

            
            

30min

            
            

16.3895

            
            

16.5456

            
            

16.4786

            
            

15.7895

            
            

15.8356

            
            

40min

            
            

16.3903

            
            

16.5459

            
            

16.479

            
            

15.7899

            
            

15.8367

            
            

50min

            
            

16.3914

            
            

16.5467

            
            

16.4792

            
            

15.7905

            
            

15.8369

            
            

60min

            
            

16.392

            
            

16.5472

            
            

16.4799

            
            

15.7911

            
            

15.8378

            

cartridge weighing 2.3 in the 105 ~ 110 ℃ drying time

actual dust monitoring, when the flue gas humidity, dust filter after the sample wet weight was significantly increased, according to specifications to dry 1 hour at 105 ~ 110 ℃ retrieved and placed into a desiccator, cooled to room temperature, weighing At this point, the cartridge before sampling, after drying extent inconsistent, the result is often too great, there are errors. Available standard blank cartridge to eliminate the error, and control the accuracy of weighing. The prepared standard blank cartridge with deionized water or distilled water, a little moist, and the sampling cartridge into the 105 ~ 110 ℃ drying, can be drawn from Table 3, the cartridge drying 4 hours basically to the standard weight of the weight standards of the standard blank cartridge blank cartridge, before and after the value difference does not exceed ± 0.0005g, that the weighing results are reliable. Otherwise, the result is suspicious, to find out the reasons or re-analyzed until qualified.

 

Table

three different drying time determination results g

            

drying time

            
            

1

            
            

2

            
            

3

            
            

4

            
            

5

            
            

1h

            
            

16.4694

            
            

16.5456

            
            

16.3267

            
            

15.6348

            
            

15.1435

            
            

2h

            
            

16.4596

            
            

16.5383

            
            

16.3182

            
            

15.6275

            
            

15 .. 1389

            
            

3h

            
            

16.4536

            
            

16.5368

            
            

16.3119

            
            

15.6223

            
            

15.1346

            
            

4h

            
            

16.4532

            
            

16.5366

            
            

16.3116

            
            

15.6219

            
            

15.1343

            
            

5h

            
            

16.3928

            
            

16.5365

            
            

16.3114

            
            

15.6216

            
            

15.1341