HJ/T 104-2003The technical requirement for water quality automatic analyzer of total organic carbon (English PDF)

3.1 Sample

The surface water, industrial sewage, and municipal sewage introduced into the automatic analyzer.

3.2 Calibration solution

Calibration solution prepared to obtain the same indicated value as the sample

TOC concentration. There are the following types.

3.2.1 Zero calibration solution.

and automatically reset to the state where the measurement is restarted.

7.4 When the sample or reagent cannot be introduced into the reactor, the

system can alarm through the buzzer and display the failure content. At the same time, STOP running until the system is restarted.

8.3 Sample introduction unit. It refers to a connection part which sends the

sample to the reaction detection unit through the sample conduit of sample of the sample after removal of inorganic carbon is first metered and sent to the oxidation reactor with a carrier gas. For example, a slide valve with a metering tube can be used.

8.5.2.2 When injecting the sample using the continuous type, the sample after

removal of inorganic carbon is sent to the oxidation reactor at a certain flow rate.

For example, a metering pump can be used.

Note. In order to perform only the performance check of reaction detection unit, any of the above injection modes shall have a construction in which zero calibration solution, span calibration solution, etc. can be introduced by this unit.

8.5.3 Oxidation reactor - It is classified into dry and wet types.

8.5.3.1 Dry oxidation reactor. The combustion tube filled with catalysts such as

platinum-based, alumina-based, or cobalt-based catalysts is kept at 680 ~

1000°C and burns the TOC in the sample introduced by the carrier gas. Dry oxidation reactors are commonly used in two ways. One is to continuously pass the carrier gas into the combustion tube. The other is to close the combustion tube for a certain period of time, and in the state where the carrier gas is stopped being passed into, the TOC in the sample is burned and oxidized.

8.5.3.2 Wet oxidation reactor. The TOC is oxidized by applying external energy such as adding an oxidizing agent such as potassium persulfate to the sample and using ultraviolet irradiation.

8.5.4 Gas-liquid separator. It refers to the device for cooling the gas sent from oxidation reactor to remove moisture from the gas. It consists of a cooler, a condenser, and a drain trap.

8.5.5 Detector. such as nondispersive infrared gas analyzer, etc..

8.6 Display recording unit. It has the function of recording the TOC value in the display form of equal division.

8.7 Data transmission device. It has a complete data acquisition and transmission system.

8.8 Attachments. The automatic analyzer of TOC can be configured with the following attachments as needed.

8.8.1 Data processing device. It expresses the TOC value in digital form and

has data processing functions such as printing and calculation.

8.8.2 Automatic calibrator. It has the function of automatically performing the zero and span calibration of the analyzer in a certain period.

to the preheating time specified in the operating manual, the preheating operation of automatic analyzer is performed, so that the functions of each part and the display recording unit are stabilized.

9.3.2 Calibration. According to the calibration method of instrument manual,

USE 9.2.2 and 9.2.3 calibration solutions for instrument zero calibration and span calibration.

9.4 Performance test methods

9.4.1 Repeatability error. Under the test conditions of 9.1, the zero calibration

solution is measured 6 times; and the average of the indicated values is taken as the zero value. Under the same conditions, the span calibration solution is measured 6 times; and the relative standard deviation of the 6 span measured values is calculated.

9.4.2 Zero drift. USE zero calibration solution for continuous measurement for

24 h. USE the initial zero value (the average of the first three measured values) during this period of time to calculate the percentage of the maximum amplitude of variation relative to the span value.

9.4.3 Span drift. In zero drift test, before and after the zero drift test, span calibration solution is used instead of zero calibration solution and is measured

3 times respectively. The average is calculated. The percentage relative to the span value is calculated from the amplitude of variation of initial span value after subtracting the zero-drift component.

9.4.4 Linearity. After the analyzer is calibrated for zero and span, the span intermediate calibration solution is introduced. After the indicated value is stable, the span intermediate value is read. The percentage OF the difference between the TOC concentration corresponding to the span intermediate value and the

TOC concentration of the span intermediate calibration solution relative TO the span value is calculated.

9.4.5 Response time. The zero calibration solution is introduced from the sample inlet. After the indicated value is stabilized, the span calibration solution is introduced. The time (min) required from the introduction of span calibration solution to reaching 90% of the final indicated value of the span calibration solution is calculated.

9.4.6 Mean time between failures. Real water sample is used for continuous operation for 2 months. The total running time (h) and the number of failures (times) are recorded. CALCULATE whether the mean time between failures (MTBF) is >=720 h/time (This index can be evaluated on site).

9.4.7 Real water sample comparison test. SELECT 5 or more kinds of real water

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