Contents
How to use this guide
This is a practical decision aid for B2B teams. Use it to align procurement, EHS, and operations on selection criteria, acceptance checks, and monitoring signals. When you have site-specific constraints (pressure range, steam purity needs, condensate return profile), share them so we can propose compliant, supply-ready options.
Scope note: This guide focuses on the scavenger decision. A well-operated deaerator (or other mechanical deaeration) and correct feed/condensate chemistry are usually the biggest levers. Scavengers are part of a system—not a substitute for fixing air in-leakage or poor DA performance.
Where it fits
- Process goal: reduce oxygen-driven corrosion (pitting, tuberculation, iron transport) and protect uptime.
- Operating window: pressure, temperature, residence time (feed/DA/storage), and where you can inject.
- Interfaces: boiler metallurgy, feedwater train, DA, economizer, condensate/return lines, storage tanks.
- Constraints: steam purity requirements, discharge limits, site EHS rules, and monitoring capability.
Why oxygen scavengers matter
Dissolved oxygen accelerates corrosion, especially at hot surfaces and in turbulent zones. Even “small” oxygen ingress can show up as rising iron, pitting, and sludge transport. Scavengers provide a chemical safety net after mechanical deaeration and help stabilize conditions during load swings or upsets.
Quick selection map (sulfite vs DEHA)
| Your situation | Often a better starting point | Why |
|---|---|---|
| Lower-to-moderate pressure boiler + simple control preferred | Sulfite (often catalyzed where needed) | Straightforward residual testing; widely used; strong “day-to-day” controllability |
| You want to minimize added dissolved solids / sulfate contribution | DEHA | Does not add sulfate/TDS the way sulfite programs can (important where conductivity/TDS is tight) |
| Condensate/return line protection is a key concern | DEHA (program-dependent) | Often considered when broader distribution beyond the feedwater point is important |
| Monitoring capability is limited and you need “easy residual control” | Sulfite | Residual sulfite test kits/procedures are commonly available and simple to trend |
| Steam purity is sensitive (e.g., turbine/critical process) | Case-by-case | Choose based on volatility/carryover risks, treatment program, and site specs—validate with your steam purity requirements |
Side-by-side comparison
High-level, practical comparison. Always confirm compatibility and program details with your water treatment specialist and SDS.
| Dimension | Sulfite programs | DEHA programs |
|---|---|---|
| What it does | Consumes dissolved oxygen; residual can be maintained as a buffer | Consumes dissolved oxygen; often used where broader system protection and solids control are priorities |
| Pressure/temperature fit | Common in many boiler applications; kinetics can depend on temperature and catalysts | Often selected when pressure/temperature and distribution goals make it attractive; program-dependent performance |
| Effect on dissolved solids | Can increase dissolved solids (e.g., sulfate contribution) and affect conductivity/TDS tracking | Avoids sulfate/TDS addition associated with sulfite; still consider total program impacts |
| Monitoring & control | Residual sulfite is typically easy to test and trend; ORP/DO trends are supportive | Residual DEHA test methods exist; trending ORP/DO and corrosion products is especially important |
| Common operational risk | Overfeed can raise solids / impact blowdown strategy; underfeed shows up as iron and pitting risk | Misalignment between feed point, residence time, and monitoring can make control feel “invisible” unless you trend properly |
| Procurement checkpoints | Assay/active %, catalyst info (if applicable), grade, stability/shelf life, COA consistency | Assay/active %, grade/purity, inhibitor package info (if any), COA consistency, handling/storage constraints |
Monitoring plan (practical)
The best program is the one you can measure and trend. The goal is to confirm oxygen control and catch air in-leakage/DA upsets early—before corrosion products spike.
| What to monitor | Where | Why it’s useful | How often (typical) |
|---|---|---|---|
| Dissolved oxygen (DO) | DA outlet / feedwater (where feasible) | Direct indicator of mechanical deaeration and oxygen ingress | Commissioning + periodic checks; increase during upsets |
| Scavenger residual | Feedwater / economizer inlet (program-dependent) | Confirms buffer and dosing stability | Daily to weekly (based on criticality) |
| ORP trend | Representative points in feed/condensate | Fast “directional” signal of reducing/oxidizing shifts | Continuous or routine spot checks |
| Iron/copper (corrosion products) | Condensate return / feedwater | Early warning of oxygen corrosion and transport | Weekly to monthly; more frequent after changes/upsets |
| Conductivity / sulfate (support) | Boiler water + feedwater | Helps interpret sulfite program impacts and blowdown strategy | Routine boiler chemistry frequency |
Troubleshooting signals
If performance drops, these are common early indicators and what to check first:
| Signal | What it often suggests | First checks |
|---|---|---|
| Rising iron in condensate/feed | Oxygen ingress, DA performance drift, or insufficient scavenger coverage | DA venting/operation, air in-leakage, feed point location, residual trend |
| Pitting / red water events | Intermittent oxygen spikes or stagnant zones | Load swings, makeup surges, condensate receiver venting, return line integrity |
| Residual “won’t hold” | Demand increased (air leak), underfeed, or measurement issue | Sample handling, test kit validation, dosing pump calibration, leak checks |
| Conductivity/TDS trending up faster than expected | Program is adding solids (often relevant to sulfite programs) or contamination | Blowdown control, makeup quality, chemistry additions, contamination sources |
| Steam purity concerns / carryover indicators | Overfeed, foaming, or mechanical carryover | Boiler water control limits, antifoam strategy, separators, feed rate stability |
If you share your pressure range, DA configuration, condensate return %, and a small trend set (DO/ORP/residual/iron), we can usually narrow down root causes quickly.
Specification & acceptance checks
When comparing products, ask for the data you can verify on receipt:
| Category | What to request | Why it matters |
|---|---|---|
| Identity | Product name/grade, manufacturer, batch/lot traceability | Ensures consistent chemistry and supports root-cause analysis |
| Quality (COA) | Assay/active %, appearance, density, pH (as supplied), impurities (if relevant) | Active concentration drives dosing stability and predictability |
| Program notes | Recommended monitoring method for residual; suggested feed point(s) | Prevents “we can’t measure it” failures and improves commissioning |
| Safety | Up-to-date SDS, handling precautions, PPE, storage segregation | Aligns with EHS review and site controls |
| Logistics | Lead time, Incoterms, shelf life, storage temperature range | Reduces downtime risk and prevents degraded product performance |
| Packaging | Drum/IBC/bulk, closures, liner type (if applicable), labeling compliance | Compatibility, safe transfers, and receiving acceptance |
Handling & storage
- Store in original, sealed packaging, away from incompatible materials (follow SDS guidance).
- Use secondary containment and clear labeling in the operating area.
- For transfers: verify hose/seal compatibility and implement spill-control basics.
- For sampling/testing: use consistent sampling points and avoid oxygen pickup in samples that can skew results.
RFQ notes (what to include)
- Boiler pressure range and typical load profile; whether you have a deaerator and where you can inject.
- Makeup water source and treatment; condensate return percentage and whether returns are “clean” or process-exposed.
- Current KPIs and pain points (iron trend, pitting, red water, DA upsets, steam purity constraints).
- Monitoring capability (DO meter availability, ORP, residual testing, lab support) and desired reporting cadence.
- Estimated monthly volume, packaging preference, delivery country, and documentation requirements (COA/SDS).
- Any compliance constraints (site restricted substances list, discharge limits, food-contact, etc.).
Need a compliant alternative?
Send your constraints and target performance. We’ll propose options with SDS/COA expectations and procurement-ready specs.
Educational content only. Always follow site EHS rules and the supplier SDS for safe use.