Proposed automatic dosing skid for pH and nitrite control in industrial recirculating cooling water.
Project Background
The client-supplied design basis includes a 5 m³ effective process-water tank, 8.5 m³/h circulation, inlet pH of 11–12, low alkalinity and hardness, and target pH of 8–11 and nitrite of 1,500 ppm. The proposed skid uses sulfuric acid and corrosion inhibitor with online analysis and Modbus TCP control, subject to confirmation of water chemistry, dosing properties, and site constraints.
Our Solution
The proposed solution is an automatic chemical-dosing skid comprising a 8.5 m³/h recirculation duty, an effective process-water tank, two duty/standby metering pumps, sulfuric-acid and corrosion-inhibitor dosing lines, pulse dampening, back-pressure valves, static mixing, and return-line injection. pH is measured continuously and used to trim acid dosing, while nitrite analysis provides a second controlled variable for inhibitor dosing or related treatment adjustment. A PLC/HMI manages interlocks, alarms, pump rotation, level control, and Modbus TCP communications. Bunding, secondary containment, compatible tubing, and an emergency spill response arrangement are proposed for chemical handling. Any sludge or concentrate is not generated in this closed-loop application; spent chemical solution is retained for controlled disposal under the confirmed SDS and local requirements. Final pump sizing, materials, control strategy, and certification will be revised after the outstanding client data are received.
What We Asked First
Please confirm the required circulation basis, sulfuric acid concentration and SDS, corrosion-inhibitor composition and SDS, normal pH setpoint, nitrite concentration basis, piping backpressure, ambient conditions, hazardous-area classification, applicable certifications, and DCS interface permissions.
Proposed Process Train
- 1Client process-water storage and equalisation
- 2Recirculation from the industrial cooling-water circuit
- 3Controlled sulfuric acid dosing for pH adjustment
- 4Controlled corrosion-inhibitor dosing
- 5Return-line blending and static mixing
- 6Inline pH and nitrite analysis with PLC/HMI feedback
- 7Off-line analysis, calibration, and safe residual handling
For Similar Projects
Prepare the process-water analysis, complete chemical SDS and dosing curves, recirculation and backpressure data, control requirements, site photographs, hazardous-area classification, and interface drawings for detailed design review.
Ref. A-014. Client identity is withheld under our client-confidentiality policy. Capacity is shown as a capacity class (design value rounded up to the next 5 at its second significant digit).
