Residential Water Treatment Training Program at Res-Kem

It was a very eventful time here at Res-Kem the past few days in training. I learned about various resins and how certain chemicals react together depending upon their positive or negative charge. I also learned how complex carbon is and how different it can vary in quality. I have a better understanding on how water treatment units are sold through independent dealers and through franchises. I learned about the physical attributes of water treatment units. Learning about mechanical and electronical interfaces on valves gave me sufficient insight on the technological advancement in the Residential sector. Understanding how the quality of water in Residential can effect people's lives is very interesting.

One of the most interesting things I observed this week was the processes Res-Kem employees must maintain in order to help move this company forward in the water treatment industry, while serving the general public.

Condensate Polishers Shipped for Local University

Last month, Res-Kem shipped a quadruple condensate polisher system to a local university. The condensate polishers are used to treat the water in the condensate loop, reducing water treatment chemical usage and reducing heat waste from excessive blowdown.
The system is comprised of four individual ASME-code stainless steel tanks with stainless steel internals, face piping, and Aquamatic valves. All external piping was a combination of welded and flanged stainless steel. Each system has an Aquamatic 962 controller to operate the valves during the backwash and regeneration cycle. The regeneration and backwash cycles are initiated by a differential pressure switch.

The local Res-Kem representative sold and installed the system at the university. The new system replaced a twin condensate polisher that had reached the end of its life.

The design flow rate is: 450 gpm
The peak flow rate is: 600 gpm
As stated above, the regeneration is initiated by a DP Switch.


The qualification process by the university was very rigorous. First university personnel visited out manufacturing facility in Aston, PA to see a similar system being built in our assembly facility. Afterwards, university personnel visited a local customer with a water softener and water dealkalizer. After we were qualified, our engineers worked with the site personnel to modify our standard design to fit the site's requirements.

Condensate Polisher Savings of 23% Realized Through Value Engineering

The white paper, "Condensate Polisher Savings of 23% Realized Through Value Engineering", shows how a value engineering team comprised of personnel from a well-known university, Res-Kem Corp, and a mechanical contractor yielded the best system for the money.

These savings substantially improved the return on investment. This was accomplished without making any compromises on the installation costs, reliability of operation, or desired operating efficiency of the powerhouse.

The Problems:
All the qualified bids exceeded the set aside level of funding. During the time lag between project approval and initiation of the bidding process, a number of variables arose which collectively now jeopardized the project in its entirety.

The cost of stainless steel, while recognized to be escalating, continued
to climb beyond all reasonable expectations.

The university’s internal cost of capital was adversely affected by a tightening of available funds within the credit market. Almost immediately, the university comptroller put the project on hold and demanded an even higher return on investment in order for the project to proceed.

The Solution:
In an attempt to move the project forward, it was decided the university utility manager would work directly with the condensate polisher manufacturer and the winning bid mechanical contractor to see how best to value engineer the product offering. The targeted goal of the value engineering team was to reduce the purchase price of the condensate polisher by a minimum of twenty percent. This together with some labor saving initiatives taken on by the mechanical contractor installing the system would hopefully rescue the project.

Value Engineering Study Items and Savings

Downsize Vessel Size -- 4% Savings

Retain stainless steel vessel -- 0%

Retain C-150 resin -- 0%

Modify external piping -- 13% Savings

Modify control valves -- 6% Savings

Total Value Engineering Savings -- 23%

As shown in the above summary, the benefits of joining together a team of
knowledgeable and experienced individuals can be readily apparent. This is particularly true when the individuals come to the task with complementary but differing skill sets combined with a shared sense of purpose.

How to Correctly Size a Sodium Cycle IX Condensate Polisher

Problem: Customer Can't Get Enough Flow through Condensate Polisher => How to Correctly Size a Condensate Polisher

Customer called to state they couldn't get enough flow through their new condensate polisher. During the service visit, it was determined that the Deaerator and Condensate system was not being operated in accordance with Best Practices Procedures presented by the US Department of Energy's Office of Industrial Technologies, Energy Efficiency and Renewable Energy.

In this case the customer was feeding softened make up water into the Condensate tank along with the returned condensate, directing this water through the condensate polisher, then sending to the Deaerator. A Sodium Cycle Ion Exchange Condensate Polisher is typically sized and designed to treat only returned condensate, not to heat up make up water. In this case the polisher needed to handle both the make up and returns. It was never sized for this.



Normally, the softened make up water goes to the inlet of the deaerator, is heated by steam to remove the dissolved gasses, stored in the deaerator storage tank and sent to the boiler. The low-pressure condensate goes to a condensate receiver, through a condensate polisher and sent to the deaerator storage tank.

Most likely, the customer was thinking the condensate return, which is hot, would heat up the make up water before going to the deaerator, thus saving energy and steam. Conventionally, deaerators are designed to take cold softened make up water and heat it up in the steam chamber to remove oxygen and CO2 before sending it to the boiler.

The best way to save energy would be to install a Boiler Blowdown Heat Recovery System. This consists of a Blowdown Flash Tank and Heat Exchanger. Simply put, with this system the boiler blowdown water goes to a Flash Tank, where the pressure is reduced from the boiler operating pressure to the Deaerator operating pressure; typically 5 psig (228 deg F). When this blowdown water pressure is reduced, most of the water flashes to steam. The steam is directed to the deaerator steam inlet. The remaining blowdown water goes to a shell and tube or coil type heat exchanger, which is used to heat the softened make up water prior to going to the deaerator. The heat exchanger also reduces the blowdown water to safe and acceptable temperature levels for drains.

Separate from this, the condensate return water, having traveled through the myriad of piping, contains iron (crud) and some hardness and needs to be "polished" before being recycled back to the boiler. The condensate polishers are designed to handle only the returned condensate, which is a percentage of original make up water. When sizing up a condensate polisher we need to know the percentage of make up water that is "returned". It is only that percentage we are concerned about when we size up the condensate polisher.

Thus, a basic system would look like this:


The better energy saving system (as described above) would look like this:


A condensate polisher is used in addition to this Boiler Blowdown configuration.

Use of a condensate polisher and a good chemical treatment program enables the customer to use less make up water and energy. When considering use of a condensate polisher it's important to size it for treatment of the condensate only.

For more information about energy savings and Boiler Blowdown Systems see attached pdf files that the government has made available via the Internet.

US Department of Energy Steam Tip Sheet - Minimize Boiler Blowdown

US Department of Energy "Boiler Blowdown Heat Recovery Project Reduces Steam System Energy Losses at Augusta Newsprint" - Best Practices Technical Case Study

Condensate Polisher Vessel Materials of Construction

We often receive the following question about the materials of construction of condensate polisher vessels.

Question: We're considering a condensate polisher in our boiler plant. Should the vessel be constructed of carbon steel or stainless steel?

Answer: Over 75% of the condensate polishers that Res-Kem builds utilize stainless steel pressure vessels. If you use a carbon steel vessel it will have to be provided with a high temperature liner for corrosion resistance. For a condensate polisher with a diameter of 30" or less, the liner can not be installed working from inside the tank and the quality of the lining is unpredictable. In fact most liner companies will not warrant their linings if the vessel diameter is less than 36".

Stainless steel vessels cost a little more however the entire lining issue goes away as one is not required. For condensate polishers 30" or less in diameter it does not make sense to even consider a carbon steel vessel with a liner.

Res-Kem builds a very economical line of standard stainless steel condensate polishers from 20 inch to 66 inch diameter vessels . Our standard designs employ stainless steel vessels, flanged and welded stainless steel face piping. Depending upon the size of the valves we use stainless steel Aquamatic diaphragm and/or butterfly valves. To save a little money, we have an option for smaller size systems using stainless steel vessels, threaded steel face piping, and cast iron Aquamatic diaphragm valves.

Condensate Polisher with All Stainless Steel Construction

Last week, Res-Kem shipped a condensate polisher designed to treat an 80 gpm flow rate with a 390,000 grain capacity. The condensate polisher had an all stainless steel construction including an ASME code stainless steel pressure vessel, stainless steel internals, stainless steel Aquamatic valves and face piping. Not shown is the brine tank used to regenerate the high strength cation resin.

Condensate polishers can save a considerable amount of energy by reclaiming waste heat that is in the condensate return from steam boilers, rather than having a large "blowdown" to drain. Treating the condensate return, and keeping the temperature high, usually around 120F, with a condensate polisher, the blowdown rate to drain can be dramtically reduced. Recent calculations show an ROI in as little as 6 months!