Hard well water and dissolved oxygen wear out most boilers at oilfield and construction camps in Oman, and a boiler corrosion inhibitor with built-in scale control is the usual fix. Camp kitchens, laundries and showers run on packaged shell boilers and hot-water generators. For these units, a multifunctional liquid treatment goes into the feedwater, typically at about 50-200 ppm. It removes oxygen before it can pit the steel and stops hardness from baking onto the tubes. Keep the boiler water inside the control limits below and blow down on a fixed routine, and you prevent most scale and pitting.
We supply boiler treatment grades from the Barka Industrial Area. The grades are Corrosion Scale Inhibitor Boiler Treatment, CorroSOL 66 corrosion and scale inhibitor and AQUATEX 6460.
What a boiler corrosion inhibitor does in a camp boiler
Camp boilers are small, low-pressure units, and the same maintenance crew also looks after generators, pumps and air conditioning. They differ from power-plant boilers in three ways. The make-up water changes from one water truck to the next. Much of the steam or hot water is used where it is drawn off and never comes back. And nobody tests the water every shift.
A boiler treatment programme has three jobs. First, it removes dissolved oxygen, normally with sulphite or tannin as the oxygen scavenger. Second, a polymer scale inhibitor and sludge conditioner holds calcium and magnesium hardness in suspension as a soft sludge. The sludge then leaves with the blowdown and does not form hard scale on the tubes. Third, it keeps alkalinity high enough (pH 10 minimum in a shell boiler) to protect the steel. A steam boiler programme should always include an oxygen scavenger and a polymer. A phosphate treatment is typically added as well, especially above about 10 bar.
Why camp boilers in Oman scale and corrode
In the interior, many camps run on trucked well water with high hardness and high dissolved solids. Without a scale inhibitor, that hardness deposits on the hottest surfaces, insulates the tube and leads to overheating. Camps near Muscat or on the coast may get RO or desalinated water. This water is low in hardness but still carries dissolved oxygen and very little alkalinity, so it can be more corrosive than hard water.
Dissolved oxygen causes pitting in boiler tubes: small, deep holes that can go right through a tube while the rest of the metal still looks sound. Boiler water pH matters in both directions. If pH is too low you get acidic corrosion, and if it is too high caustic corrosion becomes a risk, so record the pH reading in the daily log. Phosphate is also recommended in three cases: where make-up alkalinity is under 20% of TDS, where make-up is dealkalised, or where make-up is not efficiently softened. Many mixed-source camp supplies fall into one of these.
Multifunctional boiler treatment or a separate programme
A multifunctional, one-drum boiler treatment combines the oxygen scavenger (commonly sulphite or tannin) with scale-control and alkalinity agents. This is usually the right choice for a small camp with no water chemist: one drum, one dosing pump and one set of tests.
A separate programme uses an oxygen scavenger, a polymer sludge conditioner and a phosphate or phosphonate scale inhibitor as individual products. Polyphosphate and phosphonate scale inhibitors are typically dosed to hold about 25-50 ppm in the boiler water, and make-up water quality sets the actual dose. This route suits larger boilers, higher pressures and sites with someone who can test and adjust three residuals.
Hydrazine was the traditional oxygen scavenger. It is toxic, corrosive, flammable and potentially carcinogenic, so safer alternatives such as sulphite and tannin are now preferred. You may also need other products alongside the main treatment:
- alkalinity builders to raise pH
- steam-volatile amines for condensate lines
- antifoams
- acid descalers (sulphamic or hydrochloric acid with a film-forming inhibitor) to remove existing scale
The full range is listed in our boiler chemicals category.
Typical boiler corrosion inhibitor dosing and pump set-up
The right dose depends on feedwater quality, boiler design and steam rate. The residual in the boiler water tells you whether the dose is right. As a starting point, liquid multifunctional treatments of this class are typically dosed at about 50-200 ppm to the boiler feedwater.
For example, take a camp boiler that uses 8 m3 of make-up water a day. At 100 ppm, that is 0.8 kg of product per day. At a typical density of 1.05-1.20 g/cm3, the daily draw is between about 0.67 and 0.76 litres. Set the dosing pump stroke to deliver that volume over the hours the feed pump runs. Wire the dosing pump so that it runs only when the feed pump runs. Dose into the feed tank or into the feed line after the tank, never into a drum the crew tops up by hand.
After the first week, adjust the dose from the test results. Raise the dose if the sulphite reserve stays low, and lower it if the reserve stays well above the range. When the water source changes, for example from RO to trucked well water, test the same day.
Control limits and a test routine for camp crews
Typical control limits for shell boilers up to 20 bar are:
- pH 10 minimum
- Caustic alkalinity 350 mg/l as CaCO3 minimum
- Total alkalinity 1200 mg/l maximum
- Total hardness under 10 mg/l as CaCO3
- Sulphite reserve 50-100 mg/l as Na2SO3, or tannin 12-20 units
- TDS 3000 mg/l maximum
- Silica under 40% of caustic alkalinity
- Phosphate 30-70 mg/l as PO4, where phosphate is used
Every day, the camp crew should take a cooled boiler water sample. Check pH, TDS with a handheld conductivity meter, and sulphite with a drop-count test kit. Every week, also test total hardness, caustic alkalinity and, if your programme uses it, phosphate. Write every reading in a log kept next to the boiler.
When a value is out of range, act on it the same day:
- Low sulphite: increase the dose, or check the feed tank for an air leak.
- High TDS: blow down more.
- Hardness above 10 mg/l: check for a failed softener or a change of water source.
- pH below 10: increase the treatment or add an alkalinity builder.
Blowdown, layup during rig moves, and condensate return
Blowdown removes the concentrated solids and the sludge that the polymer has conditioned. Blow down often enough to keep TDS under the 3000 mg/l maximum. If your trucked well water carries 1,000 mg/l TDS, the boiler can concentrate it only about three times, so roughly a third of the feedwater has to go to blowdown. Softened or RO water needs far less blowdown and less chemical. In summer, water evaporates from open or vented feed tanks left in the sun, which concentrates the make-up before it reaches the boiler.
Oxygen enters a boiler as it cools, so an idle boiler corrodes faster than a working one. During camp demobilisation or a rig move, use one of two methods. Either fill the boiler completely with treated water and keep the sulphite reserve at the top of the range, or drain it, dry it fully and close it up.
Many camps do not return condensate, and in that case condensate treatment is not needed. Where condensate does return, a blend of volatile neutralising amines with an oxygen scavenger is typically fed continuously at 2-5 ppm to the feedwater tank or deaerator to protect the return lines.
Specification, packing, storage and PPE
| Item | Detail |
|---|---|
| Part numbers | RXSOL-42-4029-025 Corrosion Scale Inhibitor Boiler Treatment; RXSOL-42-4029-030 CorroSOL 66 Corrosion Scale Inhibitor Boiler; RXSOL-42-4029-035 AQUATEX 6460 |
| Application | Low, medium and high-pressure steam boilers: feedwater oxygen and hardness control, internal scale prevention, prevention of carryover and foaming (typical for this product class) |
| Appearance | Clear to light-coloured liquid (typical) |
| Density | 1.05-1.20 g/cm3 (typical) |
| pH as supplied | 10.5-12.5 (typical) |
| Dosage | About 50-200 ppm to boiler feedwater (typical), adjusted by boiler water testing |
Tell us which pack size suits your site, and we will confirm the packing in the quotation.
At desert sites, store drums upright in the shade, out of direct sunlight, with the caps tight. Check drums for bulging and open them slowly. Phosphate and polymer boiler treatments are often classed as non-hazardous, but prolonged contact may irritate skin and eyes. Liquid treatments of this class are also alkaline as supplied. Wear chemical goggles and gloves when filling the dosing tank. Small spills of phosphate and polymer types can be washed away with plenty of water. Follow the SDS for the grade you buy.
Where to buy boiler treatment in Muscat and Oman
Oman Chem (Muscat & Barka for Business Trading) supplies boiler chemicals from the Barka Industrial Area, Sultanate of Oman. Call +968 77333599 or message us on WhatsApp. Contact us to discuss delivery to your site.
For plants and camps near Sohar port, the same treatment is also listed on Sohar Chemical. Buyers in the capital area can find it on Muscat Chemical. To order, send your boiler size, daily make-up volume and water source through our quote request page. We will recommend a grade and a starting dose.
Request a quote on WhatsApp at +968 77333599.
Frequently asked questions
What chemical is used to stop corrosion in a boiler?
An oxygen scavenger, usually sulphite or tannin, removes the dissolved oxygen that causes pitting. Enough alkalinity to keep boiler water at pH 10 minimum protects the steel. Multifunctional boiler treatments combine the scavenger with scale-control and alkalinity agents in one product. Hydrazine was used in the past, but it is toxic and potentially carcinogenic, so safer alternatives are now preferred.
Do I still need a chemical treatment if my boiler is fed with RO or softened water?
Yes. RO and softened water still carry dissolved oxygen, and RO water has very little alkalinity, so the boiler still needs corrosion protection. Phosphate is also recommended where make-up alkalinity is under 20% of TDS, where make-up is dealkalised, or where it is not efficiently softened.
How much boiler corrosion inhibitor should I dose per day?
Liquid multifunctional treatments are typically dosed at about 50-200 ppm to the feedwater. For a boiler that uses 8 m3 of make-up water a day, 100 ppm works out to 0.8 kg of product a day. The final dose depends on feedwater quality, boiler design and steam rate. Set it by testing the sulphite or tannin residual in the boiler water.
How often should a camp boiler be blown down?
Blow down often enough to keep boiler water TDS under 3000 mg/l, the typical maximum for a shell boiler up to 20 bar. Check TDS daily with a conductivity meter. High-TDS well water needs much more blowdown than softened or RO water.
Is boiler treatment chemical hazardous, and what PPE is needed?
Phosphate and polymer boiler treatments are often classed as non-hazardous, but prolonged contact may irritate skin and eyes. Liquid grades are also typically alkaline as supplied, around pH 10.5-12.5. Wear chemical goggles and gloves when handling them, and follow the SDS for the grade you buy.
