Selection of mixed-bed regenerant and regenerant water pump? ?
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1. There is a formula for calculating the amount of regenerant required for mixed-bed resins. I wonder how those who use mixed beds (with a resin ratio of 1:2 between cationic and anionic resins) calculate the amount of acid and alkali needed for their resins’ regeneration 2. How to calculate the concentration of the regenerant, as well as the amounts of 31% acid and 30% alkali to be purchased? I looked at several options: the diameter of the mixed-bed is φ2800, with the male/female dimensions being 500/1000 mm; the regeneration pump selected has a flow rate of Q=43 m³/h – or is it 38 m³/h? The diameter of the mixed-bed is φ2500; the dimensions for the anode and cathode are 500/1000 mm. The regeneration pump selected has a flow rate of Q=40 m³/h, at a pressure of 37 m? How is the capacity of a water recycling pump calculated?
The volume of the water pump isn’t calculated, right? With a diameter of 2.8 meters, the cross-sectional area is 6.15 square meters; the total amount of resin is around 10 cubic meters. For the regeneration of the mixed-bed, the volume of regenerant required is 3 to 4 times the volume of the resin. If we use the maximum value of 4 times, and assuming a regeneration time of 1.5 hours, then a flow rate of 43 cubic meters isn’t necessary, nor is such a high head pressure required. As for the calculation of acid and alkali consumption: For cationic resins: Volume of cationic resin x 4 x 2.5% / 31% = amount of concentrated acid required; for anionic resins: Volume of anionic resin x 4 x 2.5% / 30% = amount of concentrated alkali required. This is the calculation method provided by the technical department of Hangzhou Zhengguang Resins (the resin manufacturer). As for the engineering calculations and selection rules, I’m not very familiar with them. Please let me know if there are any mistakes.
I wouldn’t dare offer advice; let’s just discuss the issues together! According to what you said: with a diameter of 2.5 m, the total volume of the resin is approximately 7.5 m³. The water volume required for regeneration is: resin volume × 3–4 = 22.5–30 m³/h. Is this the flow rate required for the regeneration water pump? With a diameter of 2.5 meters, the volume of cation resins is 2.45 m³. The amount of concentrated acid required is calculated as: 2.45 m³ × 4 × 2.5% / 31% = 0.79 m³. Therefore, the size of the acid metering tank should be around 0.79 m³ × 1.2 ≈ 1 m³. For anion resins, the volume is 4.9 m³; the amount of concentrated acid required is calculated as: 4.9 m³ × 4 × 2.5% / 30% = 1.63 m³. Thus, the size of the alkali metering tank should be around 1.63 m³ × 1.2 ≈ 2 m³. In the case of a mixed-bed reactor with a diameter of 2.5 meters, the acid injector used is of the HNP-2518 type. The flow rate at the outlet of the mixed solution is 19.89–25.2 m³/h, and the concentration at the outlet is 2.5–5%. The concentration of concentrated hydrochloric acid at the inlet is 30%, while the pressure at the outlet of the regeneration liquid is 0.12–0.2 MPa. Typically, there is one primary and one backup regeneration water pump. When one pump is in use (usually during simultaneous regeneration of acids and alkalis), the flow rate would be 19.89–25.2 m³/h × 2 = 39.78–50.4 m³/h. If regeneration of acids and alkalis takes place separately, then the flow rate of the water pump remains 19.89–25.2 m³/h. Is this the flow rate required for the regeneration water pump? By the way, by strong acids and strong bases you mean 31% and 30%, right?
The water flow rate of the stepwise regeneration water pump cannot be reduced by half directly, as during the separate addition of acid and alkali in stepwise regeneration, water is used on both sides to prevent cross-contamination and ensure proper regeneration of the resin.
Well, actually, based on the volume of your resin, the selection of the recirculation water pump is also reasonable. It is a regeneration water pump; even during step-by-step regeneration, the water consumption required for feeding acids and alkalis must be met.