Inhibited Hydrochloric Acid Descaling Guide for Sohar Plants
October 26, 2026
Carbonate and iron oxide scale in heat exchangers, cooling lines and boiler tubes at Sohar plants is commonly removed with inhibited hydrochloric acid. This is hydrochloric acid diluted to working strength with a corrosion inhibitor added, so the acid dissolves the scale while attack on the steel underneath is held down. We supply hydrochloric acid from our Barka warehouse to Sohar and Al Batinah. Before you order, check three things: the scale type, the metal, and the temperature limit of the inhibitor.
What inhibited hydrochloric acid is
Hydrochloric acid is the aqueous solution of hydrogen chloride gas (HCl). It is a strong acid that is fully dissociated in water, and it reacts quickly with carbonate and oxide deposits to form soluble chlorides. The strength that makes it a good descaling acid also lets it attack bare carbon steel once the scale has gone.
An inhibitor is an additive, usually an organic film-forming compound. It adsorbs on the clean metal surface and slows the reaction between the acid and the metal. It has much less effect on the scale, so the acid keeps dissolving deposits while metal loss stays low. You can buy inhibited acid as a ready blend, or make it up on site by adding a separate inhibitor to diluted hydrochloric acid at the rate its supplier states.
Every inhibitor has a temperature limit and a contact time limit on its data sheet. Go above either one and the protection falls away, so your cleaning procedure should state both before the job starts.
Which scale it removes and which metals need care
Hydrochloric acid works well on the deposits most Sohar plants see in seawater and cooling water service: calcium carbonate, magnesium carbonate, rust and general iron oxide. Carbonate scale fizzes as it dissolves because it releases carbon dioxide, which tells you the acid is working. Calcium sulphate and silica scale dissolve poorly in hydrochloric acid alone, so test a sample before you commit to an acid clean.
Metal compatibility decides whether hydrochloric acid is the right choice at all:
- Carbon steel and cast iron: the usual application for inhibited hydrochloric acid, within the inhibitor's temperature and time limits.
- Copper and brass tubes: commonly cleaned with inhibited acid, but check that the inhibitor is rated for copper alloys.
- Austenitic stainless steel: chlorides can cause pitting and chloride stress corrosion cracking, so many plant specifications exclude hydrochloric acid for stainless equipment. Follow your equipment maker's cleaning instructions.
- Aluminium and galvanised steel: hydrochloric acid attacks these rapidly, and an inhibitor does not make it suitable. Isolate them from the cleaning circuit.
A beaker test on a scale sample from your exchanger shows how fast the deposit dissolves and whether a residue remains.
How a descaling clean is run
For our hydrochloric acid, the product record states the dose as: Depends on use and application. The working strength for your job comes from your cleaning procedure, the scale load and the metal, so we do not give a single figure. The steps below are general good practice for an inhibited acid clean on steel equipment.
- Isolate and drain the exchanger or line, and remove or blank off any aluminium, galvanised or stainless parts that are not rated for the acid.
- Make up the solution in an acid-resistant tank. Always add acid slowly to water, never water to acid, then add the inhibitor at the rate on its data sheet before the solution reaches the metal.
- Circulate the solution with an acid-resistant pump, keeping the temperature below the inhibitor's limit. Vent the high points, because carbon dioxide from carbonate scale and hydrogen from acid contact with steel collect there.
- Monitor the acid strength by titration and check dissolved iron at regular intervals. When the acid strength stops falling, the scale has gone, and further contact only adds metal loss.
- Drain, rinse and neutralise with fresh water and then a mild alkaline rinse, and passivate the steel if your procedure calls for it.
- Dispose of spent acid after neutralisation, following the environmental permit and waste rules that apply to your site.
Hydrogen from the clean is flammable. Keep flames, hot work and spark sources away from vents and the circulation tank until the system is drained and flushed.
Where inhibited acid cleans are used in Sohar
Plants across the Sohar industrial zone run acid cleans during shutdowns and turnarounds. Steel plants clean cooling circuits and heat exchangers fouled by hard water scale. At the aluminium smelter, carbon steel heat exchangers and cooling water lines can be acid cleaned, while aluminium parts stay out of the circuit. Refinery and petrochemical units use inhibited acid on shell-and-tube exchangers where fouling has cut heat transfer.
Water plants use hydrochloric acid in other ways. Our product record lists regeneration of ion exchange resins, where cation exchange replaces ions such as Na+ and Ca2+ to produce demineralised water, and pH control and neutralisation. At Sohar port, vessel engineers use the acid for descaling seawater-cooled equipment, and the same metal checks apply.
Our hydrochloric acid: specification and packing
The products below are hydrochloric acid. If your job calls for an inhibited blend, tell us the metal, the scale type and the circulation temperature when you request a quote, and we will confirm what we can supply for that job. The full listing is on our Hydrochloric Acid Conc product page, and the larger pack is listed as Hydrochloric Acid 250 Kg.
| Item | Detail |
|---|---|
| Part number | RXSOL-19-1101-025 (Hydrochloric Acid), RXSOL-19-1101-210 (Hydrochloric Acid 250 Kg), RXSOL-19-1101-250 (Hydrochloric Acid Conc), RXSOL-60-6158-001 (Hydrochloric Acid Concentrated, lab chemical) |
| Application | Regeneration of ion exchange resins; pH control and neutralisation |
| Dosage | Depends on use and application. |
| Packing | 250 Kg (RXSOL-19-1101-210) |
| Technical specs | Molecular formula: HCl in water (H2O). Molar mass: 36.46 g/mol (HCl). Appearance: clear colourless to light-yellow liquid. Boiling point: 110 °C (383 K), 20.2% solution; 48°C (321 K), 38% solution. Solubility in water: miscible. |
Safety and handling
Hydrochloric acid in high concentrations forms acidic mists. Both the mist and the solution have a corrosive effect on human tissue, with the potential to damage respiratory organs, eyes, skin, and intestines. Upon mixing Muriatic acid with common oxidizing chemicals, such as bleach (NaClO) or permanganate (KMnO4), the toxic gas chlorine is produced. To minimize the risks while working with hydrochloric acid, appropriate precautions should be taken, including wearing rubber or PVC gloves, protective eye goggles, and chemical-resistant clothing.
On a cleaning job, keep an eyewash station within reach of the make-up tank, ventilate the vent points, and keep hypochlorite and other oxidisers away from the acid area.
Where to buy in Sohar and Oman
Sohar Chemical (RXSOL group, Oman) supplies hydrochloric acid from our Barka warehouse, with deliveries to Sohar and Al Batinah. Call +968 99489269 or message us on WhatsApp with the quantity, the delivery point in the Sohar industrial zone or at Sohar port, and the date you need it on site. For jobs in Dhofar, the acid is listed as Hydrochloric Acid Conc 50 Ltr on our Salalah site. Laboratories in the capital area can order Hydrochloric Acid LR 500 ml from our Muscat site for titration and scale testing.
Frequently asked questions
Can I use inhibited hydrochloric acid on stainless steel?
Chlorides can cause pitting and stress corrosion cracking in austenitic stainless steel, so many plant specifications exclude hydrochloric acid for stainless equipment. Follow your equipment maker's cleaning instructions and tell us the metal when you ask for a quote.
What acid strength should I use for descaling?
Our product record states the dose as: Depends on use and application. The working strength comes from your cleaning procedure, the scale load and the metal. A beaker test on a scale sample helps you set it.
Can you deliver to a vessel at Sohar port?
We deliver from our Barka warehouse to Sohar and Al Batinah. Send us the vessel name, the berth or agent details and the quantity on WhatsApp, and we will confirm delivery for your job.
To order hydrochloric acid for your next descaling job in Sohar, request a quote or send your requirement on WhatsApp to +968 99489269.
Frequently asked questions
Can I use inhibited hydrochloric acid on stainless steel?
Chlorides can cause pitting and stress corrosion cracking in austenitic stainless steel, so many plant specifications exclude hydrochloric acid for stainless equipment. Follow your equipment maker's cleaning instructions and tell us the metal when you ask for a quote.
What acid strength should I use for descaling?
Our product record states the dose as: Depends on use and application. The working strength comes from your cleaning procedure, the scale load and the metal. A beaker test on a scale sample helps you set it.
Can you deliver to a vessel at Sohar port?
We deliver from our Barka warehouse to Sohar and Al Batinah. Send us the vessel name, the berth or agent details and the quantity on WhatsApp, and we will confirm delivery for your job.
