【Daily Question】Chemical Engineering Principles 291: Water Vapor Sampling (January 11)

1. Each water vapor sampling bottle should be cleaned before sampling, and it should be rinsed with the water sample at least three times during sampling. II. When there are special requirements for the water samples taken (such as dissolved oxygen), the sampling tube should be inserted to the bottom of the bottle; after the water has overflowed for three minutes, the sampling tube should be removed and the bottle cap should be closed immediately. III. When discontinuous sampling is employed, the pipeline must be flushed prior to sampling. IV. When sampling soda water, the cooling water valve should be opened first, followed by the slow opening of the soda water sampling valve. It is advisable for the temperature of the water sample to be around 25–30°C. Sampling is not possible if steam is still being emitted. V. On the sampling tube, near the sampler, there are two valves: one is a stop valve and the other is a needle valve. Each time the unit is started, both valves must be opened in order to flush the sampler and the cooler. After steam is emitted for 10 seconds, the flow rate is adjusted. Such flushing should also be carried out regularly during normal operation of the unit; it is generally done on Tuesdays during the morning shift, with the shift supervisor performing the task and keeping records.

How to properly take vapor samples? Answer: 1) The design and installation of the sampling points are reasonable. The sampling tube must be made of stainless steel or red copper; ordinary steel tubes or brass tubes cannot be used. 2) Properly store the samples to prevent the obtained samples from being contaminated. 3) Before sampling, adjust the sampling flow rate to around 500 ml/min. 4) When sampling, the sampling tube should be rinsed, and the sampling bottle should be thoroughly cleaned.

How to properly take vapor samples? Each water vapor sampling bottle should be cleaned before sampling, and it should be rinsed with the water sample at least three times during sampling.

1. Each water vapor sampling bottle should be cleaned before sampling, and it should be rinsed with the water sample at least three times during sampling. II. When there are special requirements for the water samples taken (such as dissolved oxygen), the sampling tube should be inserted to the bottom of the bottle; after the water has overflowed for three minutes, the sampling tube should be removed and the bottle cap should be closed immediately. III. When discontinuous sampling is employed, the pipeline must be flushed prior to sampling. IV. When sampling soda water, the cooling water valve should be opened first, followed by the slow opening of the soda water sampling valve. It is advisable for the temperature of the water sample to be around 25–30°C. Sampling is not possible if steam is still being emitted. V. On the sampling tube, near the sampler, there are two valves: one is a stop valve and the other is a needle valve. Each time the unit is started, both valves must be opened in order to flush the sampler and the cooler. After steam is emitted for 10 seconds, the flow rate is adjusted. Such flushing should also be carried out regularly during normal operation of the unit; it is generally done on Tuesdays during the morning shift, with the shift supervisor performing the task and keeping records.

Answer: 1. All vapor sampling bottles should be cleaned before sampling, and during sampling they should be rinsed with the water sample at least three times. II. When there are special requirements for the water samples taken (such as dissolved oxygen), the sampling tube should be inserted to the bottom of the bottle; after the water has overflowed for three minutes, the sampling tube should be removed and the bottle cap should be closed immediately. III. When discontinuous sampling is employed, the pipeline must be flushed prior to sampling. IV. When sampling soda water, the cooling water valve should be opened first, followed by the slow opening of the soda water sampling valve. It is advisable for the temperature of the water sample to be around 25–30°C. Sampling is not possible if steam is still being emitted. V. On the sampling tube, near the sampler, there are two valves: one is a stop valve and the other is a needle valve. Each time the unit is started, both valves must be opened in order to flush the sampler and the cooler. After steam is emitted for 10 seconds, the flow rate is adjusted. Such flushing should also be carried out regularly during normal operation of the unit; it is generally done on Tuesdays during the morning shift, with the shift supervisor performing the task and keeping records.

1. Each water vapor sampling bottle should be cleaned before sampling, and it should be rinsed with the water sample at least three times during sampling. II. When there are special requirements for the water samples taken (such as dissolved oxygen), the sampling tube should be inserted to the bottom of the bottle; after the water has overflowed for three minutes, the sampling tube should be removed and the bottle cap should be closed immediately. III. When discontinuous sampling is employed, the pipeline must be flushed prior to sampling. IV. When sampling soda water, the cooling water valve should be opened first, followed by the slow opening of the soda water sampling valve. It is advisable for the temperature of the water sample to be around 25–30°C. Sampling is not possible if steam is still being emitted. V. On the sampling tube, near the sampler, there are two valves: the first one is a stop valve, and the second one is a needle valve. Each time the unit is started, both valves must be opened in order to flush the sampler and the cooler; after steam is emitted for 10 seconds, the flow rate is adjusted

1) The design and installation of the sampling points are reasonable. The sampling tube must be made of stainless steel or red copper; ordinary steel tubes or brass tubes cannot be used. 2) Properly store the samples to prevent the obtained samples from being contaminated. 3) Before sampling, adjust the sampling flow rate to around 500 ml/min. 4) When sampling, the sampling tube should be rinsed, and the sampling bottle should be thoroughly cleaned.

1. Cooling rack 1.1 Open the inlet and outlet ball valves of the cooler in sequence. 1.2 Set the backflush filter to the “operating” state. 1.3 Open the primary and secondary inlet valves for the sample water in each channel (to full open), open the drain valve to its maximum position, and drain the sample water from each channel. 1.4 Once discharge is complete, close the discharge valve. Note: 15 seconds before shutting the drain valve, set each backwash filter to the “backwash” mode to clean the filter elements; after the drainage is complete, reset the filters to the “operational” mode. 2. Manual sampling tray 2.1 Open the sample water valve of the manual sampling tray. 2.2 Call up the manual sampling flow rate. 3. Dashboard 3.1 Remove the sample water filter elements for each gauge. 3.2 Open the throttle valves at each inlet on the dashboard to introduce the sample water into the instrument transmitter. Note: When draining the sample water pipeline of the instrument, please remove the electrodes from each transmitter. 3.3 Adjust the regulating nut of the constant pressure valve according to the number of instruments associated with each sample stream, so that the total flow rate of the sample water meets the required specifications. Note: DD and PH use 300 ml/min, O2 uses 500 ml/min, and other meters use 150 ml/min. 3.4 Adjust the throttle valve at the meter inlet based on the indicated value of the flow meter, so that the flow rates of the water used in testing the instruments meet the requirements specified in the power plant regulations.

How to properly take vapor samples? 1. Each water vapor sampling bottle should be cleaned before sampling, and it should be rinsed with the water sample at least three times during sampling. II. When there are special requirements for the water samples taken (such as dissolved oxygen), the sampling tube should be inserted to the bottom of the bottle; after the water has overflowed for three minutes, the sampling tube should be removed and the bottle cap should be closed immediately. III. When discontinuous sampling is employed, the pipeline must be flushed prior to sampling. IV. When sampling soda water, the cooling water valve should be opened first, followed by the slow opening of the soda water sampling valve. It is advisable for the temperature of the water sample to be around 25–30°C. Sampling is not possible if steam is still being emitted. V. On the sampling tube, near the sampler, there are two valves: one is a stop valve and the other is a needle valve. Each time the unit is started, both valves must be opened in order to flush the sampler and the cooler. After steam is emitted for 10 seconds, the flow rate is adjusted. Such flushing should also be carried out regularly during normal operation of the unit; it is generally done on Tuesdays during the morning shift, with the shift supervisor performing the task and keeping records.

Answer: 1. All vapor sampling bottles should be cleaned before sampling, and during sampling they should be rinsed with the water sample at least three times. II. When there are special requirements for the water samples taken (such as dissolved oxygen), the sampling tube should be inserted to the bottom of the bottle; after the water has overflowed for three minutes, the sampling tube should be removed and the bottle cap should be closed immediately. III. When discontinuous sampling is employed, the pipeline must be flushed prior to sampling. IV. When sampling soda water, the cooling water valve should be opened first, followed by the slow opening of the soda water sampling valve. It is advisable for the temperature of the water sample to be around 25–30°C. Sampling is not possible if steam is still being emitted. V. On the sampling tube, near the sampler, there are two valves: one is a stop valve and the other is a needle valve. Each time the unit is started, both valves must be opened in order to flush the sampler and the cooler. After steam is emitted for 10 seconds, the flow rate is adjusted. Such flushing should also be carried out regularly during normal operation of the unit; it is generally done on Tuesdays during the morning shift, with the shift supervisor performing the task and keeping records.