Polymer Profile: AN977
Hydrolysis degree: ~70% (i.e., ~70 % of amide groups converted to carboxylate), resulting in strong anionic charge
Molecular weight: Approximately 13–14 million Da (13–14 MDa) — extremely high molecular weight, high bridging capability
These properties make AN977 extremely efficient in high-salinity and hardness-laden aqueous environments, as well as in systems requiring high viscosifying or flocculation power.
1. Enhanced Oil Recovery (EOR) – Tertiary Oil Recovery
1.1 Polymer Flooding
With its high molecular weight and strong anionic charge, AN977 is ideal for polymer flooding operations in oil reservoirs, particularly sandstone, to improve sweep efficiency and displace trapped oil pmc.ncbi.nlm.nih.gov.
Salinity/hardness tolerance: The high hydrolysis tolerance confers stability in saline/brackish water with high divalent ion content (Ca²⁺, Mg²⁺), reducing precipitation risk at ~70% hydrolysis cutoff.
Viscosity generation: At extremely low concentrations (100–1,000 ppm), AN977 builds viscosity in injection water, mitigating water channeling and improving the mobility ratio.
Thermal/chemical stability: Its polymer backbone resists thermal degradation and salinity effects better than oxygen‑link-based polymers.
As a result, AN977 is widely used in onshore and offshore EOR operations, where temperature, salinity, and hardness challenge polymer performance.
2. Water Treatment and Clarification
Though AN977 was originally developed for oil recovery, its high molecular weight and charge density make it suitable for industrial wastewater clarification, especially in high-salinity or high-TDS systems:
Saline/industrial brine treatment: Effective in brackish-water or treated water reuse systems, including power plant desalination brines or produced water from oil & gas.
Flocculation in high ionic strength: Performs well under high hardness and ionic strength conditions where typical HPAMs precipitate or lose efficacy.
Fine particle removal: Great for suspended fine solids, colloidal clays, silica slimes or metal hydroxide colloids; facilitates settling and filtration.
Flocculation dosage ranges typically are in 1–10 mg/L scale, depending on turbidity and load.
3. Tailings Dewatering and Mining Operations
In mining or mineral processing applications, especially where saline process water is involved, AN977 offers benefits:
Tailings thickening/drying: Promotes rapid floc formation and consolidation in saline/high-TDS slurries.
Process water recycling: Clarifies recycled water containing divalent ions, enabling reuse in circuits.
Compatibility with heavy ions: Performs robustly where other HPAMs fail due to calcium or magnesium interference.
This polymer is particularly suited for phosphate, copper, coal, or oil sands operations involving saline water.
4. Sludge Dewatering in Desalination or Industrial Effluents
In industrial wastewater plants dealing with brackish or high TDS streams (e.g., cooling tower blowdown, membrane reject), AN977 offers efficient conditioning:
Dewatering feed sludge: Converts fine sludge into filterable, drain-friendly flocs.
Compatibility with mechanical dewatering: Enhances performance of centrifuges, belt filter presses, or screw presses even under saline conductivity.
Compared to conventional PAM, AN977 maintains bridging ability and drainability in challenging ionic waters.
Application Advantages of AN977
Feature Benefit
High molecular weight Ultra‑effective bridging at low dose
70 % hydrolysis Maintains anionic charge and tolerance in hard/high salinity water
Strong charge density Fast neutralization of colloids and fine particles
Salinity and hardness stable Effective in brackish, seawater, or mineral-rich waters
Low sludge volume Efficient solid-liquid separation; easier disposal
Thermal/chemical stability Suitable for reservoirs or treatment systems at elevated temperatures
Usage Notes & Best Practices
Dilution: Prepare working solutions at 0.1–0.5% by mass; ensure thorough mixing—high MW* polymers can be viscous.
Dosage range: For EOR, ~500–2,000 ppm; in clarification/dewatering, typical jar tests determine optimal 1–50 mg/L.
Jar testing: Essential in your water or tailings matrix to determine floc size, settling rate, and residual turbidity.
Temperature: Stable up to ~70 °C; avoid prolonged exposure beyond to prevent hydrolysis.
Compatibility: Works well with coagulants (e.g. ferric chloride, alum) for dual-stage clarification; pre-acidification may be beneficial in extreme hardness.
Comparison with Conventional HPAM
While typical partially hydrolyzed PAMs (HPAM) are used in EOR and water treatment, they often have lower hydrolysis (20–40 %) and molecular weight (~5–10 MDa). Under high-salinity/high-hardness conditions, traditional HPAMs suffer:
Precipitation (salting out)
Loss of viscosity
Inadequate floc formation or bridging
In contrast, AN977’s 70 % hydrolysis and >10 MDa molecular weight ensure it remains structurally intact and functional in saline water, offering superior performance for both EOR and difficult water treatment scenarios.
Summary
AN977 (anionic polyacrylamide with ~70 % hydrolysis and ~13–14 MDa molecular weight) is engineered for robust performance in saline, high-hardness, or thermally challenging environments. Its primary application is in enhanced oil recovery (polymer flooding), where it improves displacement efficiency in continued water injection operations with brackish or harsh water. Additionally, it performs exceptionally in water treatment, mining, and dewatering operations where conventional polymers fail due to salinity or hardness.
If you'd like help comparing it with lower‑hydrolysis AN grades, designing jar tests, or optimizing dosage for a specific water or tailings matrix, just let me know!
