What you need to know about industrial boiler water treatment

We help businesses with industrial boiler water treatment and pre-treatment to keep their steam boilers in the best condition. Without the proper maintenance and water treatment, industrial boilers can become corroded, and more chemicals are used as part of operation.

Ryan O’Leary is one of our experienced project engineers. He works with industrial boilers for all kinds of businesses, helping them develop the right industrial boiler water treatment processes. Here he has shared his expertise and answered the main questions around industrial boiler water treatment and pre-treatment. 

ryan

What are industrial steam boilers used for?

Organisations rely on industrial boilers for a range of purposes, using the heat given off from the steam and the steam itself.

Steam pipes in tanks are used to heat oils, solvents, or other liquids to decrease the viscosity of the medium, making it easier to transport between tanks and tankers.

Steam boilers are used in the sterilisation of equipment, where high temperatures are employed alongside, or instead of, chemical treatments. Other uses can be simple as providing large volumes of steam for industrial ironing applications.

What industrial boilers are typically used?

Most boilers that we treat are fire tube boilers. These offer a good steam tonnage but take a while to get going from cold. We also treat coil, or “once through” boilers. These are much smaller but go from cold to generating steam much faster than a fire tube boiler.

Why is industrial boiler water treatment required?

As with any situation where water and metal are in contact with each other, steps need to be taken to protect the steel internals of the boiler from the corrosive nature of water.

What is industrial boiler pre-treatment?

Boiler pre-treatment means preparing the raw water to make it suitable for use in the boiler. The most common is a water softener, but a de-alkalisation plant may be required if high levels of alkalinity are present in the water.

High output boilers may benefit from a reverse osmosis unit as this will reduce the feed water TDS. This means the boiler requires less frequent blowdowns, which leads to energy and chemical cost savings.

What does industrial boiler water treatment typically involve?

Chemical treatment is typically dosed between the hot-well and the boiler and is set to dose when the boiler feed pump runs in most applications. This is done to make the chemical dosage predictable with relative usage.

The chemicals used involve an alkalinity builder to raise the pH of the water, making the water less likely to cause corrosion.

An oxygen scavenger is used to remove any dissolved oxygen in the water to prevent a form of corrosion known as “pitting”, and a hardness inhibitor to act as a last resort should there be a fault on the pre-treatment softener.

Biocides and anti-foaming agents can be dosed should the need arise. No two boilers are the same, so the chemical mix and dose rate will be different for each boiler.

Who usually carries out industrial boiler water treatment and pre-treatment?

Pre-treatment softeners are usually included as part of a new boiler package. The day-to-day monitoring of the water hardness level from the softener, and the salt level required to regenerate the softener resin, is the responsibility of the on-site operatives.

These actions take less than 5 minutes to do. Basic boiler tests are also expected to be done by on-site operatives as they will give a picture of the boiler water levels to reference between visits.

Tests include the pH of the boiler water, the TDS level of the boiler water and possibly a measure of the oxygen scavenger (if this is known to fluctuate or be at a critical level).

Monthly visits by a water treatment engineer provide a full picture of your feed and boiler water. Our engineers adjust dose rates as required (up or down) and we provide guidance on mechanical involvement like blowdown frequency and duration to best fit the needs of your system while we are not on site.

We offer package contracts that include monthly boiler testing with regular servicing of pre-treatment equipment. These packages help our customers with their everyday procedures and to give peace of mind that all boiler pre-treatment and treatment is in hand.

Why is it essential?

Industrial boiler water treatment is essential as it reduces the load on the chemical treatment. The chemical treatment is essential as it reduces the corrosion of the boiler internal surfaces. Both are required to guarantee long boiler life.

What happens if the incorrect pre-treatment is carried out?

The “wrong” pre-treatment would usually imply that either something is missing from the pre-treatment e.g. a de-alkalisation plant (as there is something unusual about the feed water), or the equipment used is poorly sized, meaning the equipment is not functioning correctly for the task at hand.

Situations like this make the chemical monitoring of the boiler much more difficult, as fluctuating pre-treatment equipment performance can lead to over- and under-dosing of chemicals to bring the levels into spec.

A missing piece of equipment would mean the levels may need to be more compromised to balance the nature of the water with the chemical requirements.

What is the cost or damage to the business?

Chief amongst this is downtime. Boilers are typically integral pieces of the production machine and if the boiler stops working, production stops.

On top of this, fixing an industrial steam boiler isn’t cheap. Retubing a fire tube boiler from corrosion damage is costly and avoidable. Boiler treatment and pre-treatment are tools for prevention and should not be deemed as an unnecessary expense. The repair bill will likely cost multiple times more than an annual contract, chemical included!

How do you know what the correct pre-treatment to use is?

The answer to this is twofold. Firstly, we test the pH, alkalinity, TDS, and iron level of the raw incoming water to determine what equipment is needed. On the other hand, we can identify if there is an excess (or absence) of something by testing the boiler water. In these cases, equipment is installed to suit and mitigate the peaks/troughs of chemical level.

Is there any other advice or information you can give?

Boiler treatment is an act of patience. It involves the tweaking of procedures and dose rates to get to the perfect set up, allowing the boiler water to adjust to the new set up and moving forward from there.

Sometimes a new boiler is within the ideal working range within two months. In other cases, what is expected to be a suitable chemical mix falls short on one or two parameters. Then, a different chemical is needed to round out the requirements of your boiler system, without simply increasing the dosage and using more chemical! Stay patient and monitor it closely, and the right process will be achieved.

We hope this article has provided plenty of useful information on industrial boiler water treatment and pre-treatment. For more details or to arrange a survey for your business, contact us on 0113 232 0005 or sales@excelwater.co.uk.

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