How to control and adjust the catalytic drum water sample
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How should the alkalinity, phosphate levels, pH, and chloride ions in the water sample from the boiler’s drum be controlled and adjusted? (In our plant, phosphate is usually added only to the drum.) Our current methods of control involve increasing the frequency of wastewater discharge when these parameters are too high, and adding trisodium phosphate through a chemical dosing pump when the phosphate levels are low; there are no other means of adjustment. At present, the alkalinity and pH of the water sample from the drum remain quite high, and the water in the boiler even turns red. All we can do currently is to keep discharging wastewater. Also, where exactly should the water samples from the drum be taken? (We take samples from the drum’s regular drain.) Also, should the root valve of the drum’s regular drain be fully open? I hope to receive guidance from all the teachers. Thank you!
If the boiler water turns red, it indicates a serious problem; it is necessary to check whether the dissolved oxygen level in the feedwater and the iron ion concentration in the boiler water are within acceptable limits. It needs to be dealt with as early as possible, and the scheduled discharge volume should be increased.
A PH value control of 9 is sufficient; it helps to reduce the amount of ammonia needed for injection. Yours is probably located in the power plant’s main soft water system. The bottom valve of the drum is not opened fully for regular drainage, in order to prevent the drainage valve from failing to open completely; a bypass line has been installed on the drainage valve to prevent it from freezing
1. Regulation principle: First, focus on controlling the conductivity of the furnace water; in other words, stabilize the furnace water conductivity before attempting to control other parameters. Under normal conditions of chemical dosing and regular discharge, the main means of adjusting conductivity is to increase or decrease the continuous discharge rate. Its regulation can be achieved in two ways: one is by increasing or decreasing the opening degree of the valve of the blowdown expansion tank, and the other is by increasing or decreasing the opening degree of the valve of the boiler water sampler. Serial adjustment refers to the former, and the valve opening should be adjusted in steps. 2. Boiler water pH: If low, reduce the continuous drainage rate, increase the boiler water conductivity appropriately, and raise the dosage of chemicals accordingly ； If it is too high → Open the series control valve to appropriately reduce the conductivity of the boiler water, and decrease the dosage of chemicals accordingly. 3. Boiler water PO43- concentration: Low or 0 → Check whether dosing is proper, whether the drain rate is too high, and whether the boiler water conductivity is too low → Increase the dosing amount appropriately, reduce the drain rate, and raise the conductivity ； If it is too high → Open the series control valve to appropriately reduce the conductivity of the boiler water, and decrease the dosage of chemicals accordingly. 4. Steam Na+ ions: Slightly high or high level → Check whether the conductivity is too high, examine the sampling process, and check the drum liquid level → Open the large-diameter drain control valve to appropriately reduce the conductivity of the boiler water ； Ions are severely above the limit, by thousands → Check the sampler → Check the sampling process. 5. Excessively high conductivity → Open the large-diameter regulating valve and appropriately reduce the dosage of chemicals added ； Too low conductivity → Reduce the series control valve and increase the dosage of chemicals appropriately.
Well, now we are increasing the frequency of water discharge in order to control the color of the water. Teacher, why does the water in the boiler turn red?
Teacher, we are using the demineralized water from the power plant; no ammonia is added to the steam drum, and the pH level is too high to be brought under control.
Teacher, you are so professional! It’s a pity we don’t do conductivity testing here.
Is that so? Have you read carefully the reply I sent? Have you taken a close look at the relationships between the parameters? Analysis might not be possible, but there are still relationships between the parameters; one must apply what has been learned in practice!
1. I didn’t hear you mention what the dissolved oxygen level is; it should normally be kept at ≤15.
2. The drum should be equipped with a drain line – I’m not sure if you have one.
3. We take samples from the drain line.
4. I think the valves at the base of the regular drain valve should be fully open.
5. Regarding pH, first ensure that the deionized water supplied by the chemical treatment system has stable quality, and then adjust it through dosing, drainage, and regular discharge
2. The drum should be equipped with a drain line – I’m not sure if you have one.
3. We take samples from the drain line.
4. I think the valves at the base of the regular drain valve should be fully open.
5. Regarding pH, first ensure that the deionized water supplied by the chemical treatment system has stable quality, and then adjust it through dosing, drainage, and regular discharge