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If you are using boilers to create steam within your facility, boiler water treatment and chemistry are two things you really need to be aware of. Just like any other area of your facility’s operation, you need to make sure that your boilers are working within the right chemical parameters – if not, you risk reducing your operating efficiency and even damaging your equipment.
Why do you need to treat your boiler water?
Boiler water treatment and management is often forgotten about or ignored. After all, this water is not intended for human or animal consumption, nor is it being released into the local water table. With this in mind, is it really so important to treat your boiler water? In fact, it is important for several key reasons.
- Heat exchange efficiency
Your facility draws upon power and energy resources in order to provide heat to the boiler. This heat then needs to be transferred to the water housed within in order to alter the state of the liquid water into liquid and gaseous steam. Of course, this costs money and has an environmental impact.
This means businesses need to focus on maximizing the efficiency of this heat exchange. If there are impurities within the water or the water chemistry is not optimal, this may result in significantly reduced levels of efficiency. In turn, this means increased operating costs and heightened ecological impact.
- Protection from corrosion
When you invest in a boiler, you do so with long-term operation in mind. If you find that you need to replace your boiler, your pipes, your valves, or any other equipment in the system after only a few years of usage, this is a serious cost inefficiency and will leave you with a hefty bill.
Water will corrode the inside of your boiler and your system. However, treated water – and water with the right chemistry – will reduce the rate of corrosion, extending the lifetime of your equipment. This makes proper water treatment crucial to your business.
- Output quality
While some impurities or other particles will be left behind when the water is changed into steam, impure water or water with the wrong chemistry will still result in a reduction to the steam output quality.
Treating the water and balancing its chemistry is important as you target high-quality steam output at your facility.
Optimal water chemistry guidelines
So what do you need to be looking for when you assess your water chemistry? Boiler water chemistry needs to adhere to the following guidelines.
- pH level
- 10 or 11
The pH level of the water needs to be kept relatively high compared to the more neutral character of water intended for other applications. A pH of 10 to 11 is ideal, while 9.5 should be viewed as a minimum. This moderately alkaline pH level prevents corrosion within the system.
- Hardness
- Fewer than 50 parts per million (ppm)
When we discuss the hardness of water, we are really referring to the general presence of a number of different mineral ions, specifically calcium and magnesium ions, in the water itself. Ideally, you need your boiler water to be as soft as possible – a level of 50 ppm or below is considered to be very soft – to prevent the buildup of scale within your system.
- Phosphates
- 30 to 50 ppm
Phosphates can be used to reduce the level of calcium ions that are found in the boiler water, which is a useful means of reducing water hardness. As such, you need to make sure that this mineral is present in your water. However, in order to ensure that the pH of the water does not become unbalanced, you need to keep the level of phosphates within a very specific range.
- Dissolved solids
- Less than 700 micro ohm-centimeters (ohm-cm)
Solids may either be suspended in the boiler water, in which case they can be filtered out of the water with relative ease, or have been dissolved into the chemistry of the water itself. Facility managers can gain an idea of the level of dissolved solids in the water by testing its conductivity. A conductivity test should provide a reading of less than 700 micro ohm-cm of resistance. If the resistance level is greater than this, blow down may be needed to remove solids from the system.
- Chlorides
- 30 to 50 ppm
Buildup of chlorides in the system is an indicator that the solid content of the boiler water has become too high, which makes a chloride test another useful tool in analyzing solid content, alongside the conductivity test. A level of chlorides above 50 ppm may suggest that blow down is required to remove solids from the water within the boiler and pipes.
- Oxygen
- Fewer than 0.007 milligrams per liter (mg/l)
It is difficult to avoid a level of dissolved oxygen content within your boiler water. This is because atmospheric oxygen is soluble in water, and it is both expensive and unnecessary to eliminate all content between your supply water and atmospheric oxygen. However, if the level of oxygen becomes too high, this can cause problems of its own, especially regarding corrosion to the interior of your system. Dissolved oxygen should be minimized wherever possible and should never go beyond 0.007 mg/l during water testing. If the level grows too high, the lifespan of your system will suffer.
- Sulfites
- A minimum of 20 ppm
Sodium sulfite is often added to boiler water to assist with the chemical removal of any dissolved oxygen content. In order to successfully remove dissolved oxygen from the system, make sure that sulfite levels are kept above the minimum of 20 ppm.
Secure long-term efficiency with the right approach to boiler water treatment and chemistry
Getting your water chemistry right is crucial to the ongoing efficiency of your system. Get it wrong, and you could find yourself needing to replace key components sooner rather than later, contributing significantly to your overall operating costs and reducing the effectiveness of your facility.