If you’re in charge of treating and maintaining a steam boiler, or simply looking to reduce operational costs, focus on improving heat transfer efficiency. Keeping your steam boiler as clean as possible helps maintain heat transfer efficiency by preventing scale and corrosion, in-turn lowering water and chemical consumption. With the right equipment and training, our clients see the results of increased steam boiler performance through a reduction in scale, gas usage, and water usage. Here are the top actionable steam boiler treatment strategies that you can use to increase performance and cut costs.

Automate Surface Blowdown

Blowing down your steam boiler is necessary to reduce the concentration of impurities and mineral buildup, but there’s more than one way to do it. Typically, we find that 50% of facilities blowdown manually. If done manually, it is less likely that your blowdown timing will be precise enough consistently to achieve close to the best theoretical results for your system. If you are blowing down too much, you will waste gas and man hours. Not blowing down enough introduces scale risk, which can happen a lot faster than in a cooling tower. 

The most efficient facilities precisely control blowdown by installing controllers and automated valves. Implementing automated blowdown can also reduce the risk of boiler carryover by purging conductivity. Low pressure systems are especially susceptible to boiler carryover, which occurs when anything other than clean steam leaves the boiler. This can cause water levels to drop in the boiler, valves to clog over time, and in a worst case scenario, a “water hammer” event where pipes can burst.

Increase Cycles of Concentration with Pretreatment Filters

Another pretreatment strategy to consider is to add a membrane filtration such as reverse osmosis, which allows you to run very high cycles since a high degree of the TDS / conductivity is removed. But in this case, you actually have to add back some alkalinity to raise the pH. RO water removes alkalinity to a high degree, which by itself is not bad for boilers, but  it also lowers pH further than other pretreatment steps, which we noted earlier is a major corrosion factor. There is also the additional expense of cleaning, maintaining and replacing the membranes, so you’d have to evaluate whether this plus the cost of water treatment chemicals to raise the pH makes up for the potential savings.

If you are using steam for certain applications such as sterilization of medical instruments or food processing, an RO may be necessary or desired to meet regulatory standards 

Evaluate Condensate Return

Steam boilers run higher cycles of concentration than in cooling towers, because there’s no deliberate evaporative water loss and there are generally softeners employed as pretreatment to remove hardness, a major scale-forming factor. So, often you’re more worried about fuel consumption than water efficiency in a boiler. When you purge steam through blowdown, you’re losing heat that has to be regenerated by burning fuel. If you are not blowing down, steam condenses back in the pipe network and flows back into the DA tank. The more of this “condensate recovery” that is happening, the more heat you can keep in the system. Plus, condensate return is highly pure water, so there’s not much conductivity or hardness to treat with more chemicals. 

To improve condensate recovery, the facility needs to improve steam traps and find/eliminate leaks. EAI can help calculate condensate return and discover indicators of leaks or bad steam tracks, but it is a mechanical contractor that would have the expertise to implement physical improvements. We include condensate return measurements in our service reports.

Maximize Chemical Usage

There are four main types of chemicals used in the treatment of steam boilers:

1. Oxygen scavengers: Are added to boiler feedwater to de-airate. We use sulfites because they are safest and most cost effective. There are other types of oxygen scavengers that we don’t use because they are carcinogens. 
2. Neutralizing Amines: Added to increase the pH to prevent corrosion from water that is too acidic
3. Scale and corrosion inhibitors: Phosphates, phosphonates, organophosphates (OP), polymers
4. All-in-one blends

Striking the right balance of chemicals is important. Too much, and you’re wasting money. Too little, and it’s pennywise and pound foolish. Not knowing is a recipe for inefficiency, wasted resources, and equipment damage.

Start with a water quality assessment and consult with an expert on where you can save on chemicals. This could be using different amounts or reducing or eliminating the need for others with non-chemical treatment solutions.

It’s important to reassess your chemical blends frequently. Water quality can change for many reasons. For example the source or boiler feed water changing from environmental or human interventions can put your chemistry out of whack.

A process for frequently checking the system vitals on-site and remote monitoring solutions can be useful here. More on that in a moment. We find the best facilities are testing water quality (specifically, conductivity) 3x a day!

Reduce Amine Usage Significantly with Addition of De-Alkalizer

Steam condensate wants to react with carbon dioxide and create extremely corrosive carbonic acid. Some water treatment systems add Amines, a pH buffer to keep the pH high and prevent acidic corrosion. 

Amines are expensive, so the less you need to use the better. Adding a de-alkalizer pretreatment step cuts down on the amount of amine chemistry needed or eliminates it altogether. 

Besides the high cost, there are some other reasons why you might not want to use amines. First, amines are a controlled substance tracked by the California Department of Justice. If your water treater is not getting proper documentation from you and reporting to CA DOJ (similar in other states as well), you could be incurring unknown legal risk. Second, some applications that sterilize with steam such as food processing cannot use amines (aka morpholine), because it is not food safe.

So how do you avoid using amines? Dealkalizer is a resin bed similar to a water softener, which will remove carbonate-based types of alkalinity. It uses salt and caustic to regenerate the resin. In boiler water, alkalinity breaks down and produces CO2 gas, which would otherwise form carbonic acid and drive corrosion. 

Optimize Deaerator tanks (DA) To Save Water

Deaerator tanks (DA) at the right temperature and pressure settings reduce oxygen and cut down on the amount of sulfites that you need to add to the system. Sulfites are oxygen scavengers that increase conductivity, and boiler blowdown is based on conductivity. So less sulfites means less water lost to blowdown. 

Here’s how it works. A DA tank is a storage tank that holds incoming water from a softener. The system sends some of the steam from the boiler to raise the DA tank temperature, raising the pressure in the tank. This causes any oxygen to dissolve. You are “mechanically scavenging” the oxygen so you don’t have to use so much chemical scavenger. This cuts down on chemical and freight costs, with the added bonus of sending less chemical to the sewer (lowering your environmental footprint).

Operator Training

Water technology is a lot like golf technology. You can buy Scottie Scheffler’s club but that doesn’t mean you’ll make it onto the green more consistently. But he can probably put the ball in the same spot with any club. Knowing how to assess the situation and use the equipment is an important part of water treatment. One of the key services that EAI offers is operator training and facility support. Think of us like having a pro with you on the course – here to help analyze your swing (water program), navigate the course (your facility), improve performance, and get your operations budget into the green.

Strategy Implementation

These are just a few of many boiler water treatment strategies that can improve the performance of your system. Harness them and your facility can save on fuel, water, and chemical costs. If you need help along the way, reach out to EAI anytime for a free consultation.