Can a low-dosage Cationic Polyacrylamide Industrial Flocculant work effectively with inorganic coagulants like PAC for oilfield produced water treatment
2026-10-15
For onshore and offshore oilfield operation teams, the treatment of large volumes of produced water with complex oil content and suspended solids is one of the top priorities to meet strict discharge or reinjection standards, and Ewooan as a specialized water treatment chemical manufacturer has run more than 70 on-site produced water treatment projects for global oil and gas clients. The Cationic Polyacrylamide Industrial Flocculant is widely recognized for its extremely high flocculation efficiency at very low dosages, and its compatibility with common inorganic coagulants like PAC directly determines the overall treatment cost and final effluent quality. This article breaks down verified field data and optimized dosing strategies, proving that properly matched low-dosage formulations can deliver far better performance than single-coagulant treatment solutions.
Performance Comparison of Combined Dosing
Based on Ewooan’s on-site test data from 12 oilfields, the table below lists the treatment performance of different dosing combinations for typical produced water with 350mg/L oil content and 220mg/L suspended solids:
| Dosing Combination | Total Chemical Cost Per Ton Water | Final Suspended Solids | Final Oil Content |
|---|---|---|---|
| PAC only (2000ppm) | $0.21 | ≤ 25mg/L | ≤ 18mg/L |
| Low-dosage Cationic Polyacrylamide Industrial Flocculant only (8ppm) | $0.08 | ≤ 40mg/L | ≤ 22mg/L |
| PAC (800ppm) + Low-dosage Cationic Polyacrylamide Industrial Flocculant (2ppm) | $0.09 | ≤ 8mg/L | ≤ 5mg/L |
Core Optimized Co-Dosing Guidelines
- Staged sequential dosing process: First add PAC into the rapid mixing tank at 200-300rpm stirring speed, wait for 30 seconds to complete the destabilization of tiny oil droplets and colloidal particles, then inject the diluted low-dosage Cationic Polyacrylamide Industrial Flocculant under slow 50rpm stirring. This sequence can maximize the bridging effect of the polymer chains and form large, dense and fast-settling flocs.
- Cationicity matching principle: Select a medium cationicity 30%-40% low-dosage Cationic Polyacrylamide Industrial Flocculant to work with PAC. This formulation has the perfect charge density to capture the small micro-flocs formed by PAC, without causing excessive charge stabilization that keeps fine particles suspended.
- Dosing point distance optimization: The distance between the PAC dosing port and the flocculant dosing port must ensure at least 30 seconds of full mixing time in the pipeline. Too short a mixing time will make the two chemicals react directly with each other in the water, completely losing their respective flocculation functions.
- Salinity adaptation adjustment: For high-salinity produced water with total dissolved solids over 100,000ppm, slightly increase the molecular weight of the low-dosage Cationic Polyacrylamide Industrial Flocculant to maintain sufficient molecular chain stretching and bridging performance.
Cationic Polyacrylamide Industrial Flocculant FAQ
Q: Why can the combined dosing of PAC and low-dosage Cationic Polyacrylamide Industrial Flocculant reduce total chemical cost significantly?
A: PAC alone requires a very high dosage to form large enough flocs that can settle quickly. Adding only 1-3ppm of the low-dosage flocculant can replace more than 60% of the PAC dosage, cutting the total chemical consumption cost by more than 55% while achieving far better effluent quality.
Q: What negative effect will happen if the high cationicity (above 60%) Cationic Polyacrylamide Industrial Flocculant is used together with PAC?
A: Excessively high positive charge density will cause the surface of all destabilized particles to carry the same positive charge again, resulting in re-stabilization of colloids. This will make flocs extremely fine and difficult to settle, leading to a sharp rise in the suspended solid content of the effluent.
Q: Can the combined treated produced water meet the reinjection standard for low-permeability oil reservoirs?
A: When using the optimized combined dosing process, the median particle size of suspended solids in the treated effluent can be controlled below 2μm, fully meeting the strict reinjection requirements for low-permeability oil reservoirs, and avoiding reservoir pore blockage risks.
As a water treatment chemical brand focused on oilfield application scenarios, Ewooan provides every batch of Cationic Polyacrylamide Industrial Flocculant with free on-site water sample testing and customized dosing ratio optimization service. Contact us today to get your free produced water treatment test report and cost-saving solution, to achieve both low operating cost and compliant effluent quality.