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.

Stainless Steel vs Lined Carbon Steel Vessels for Industrial Water Softeners

Recently we received the following question from a prospective customer:
Question:
We are trying to decide whether to purchase stainless steels or lined carbon steel vessels for our industrial water softeners. We currently have old stainless steel units we inherited from a sister plant. These tanks are corroded. What is Res-Kem's position on buying stainless steel versus lined carbon steel tanks for our water softeners?

Our Answer:
Res-Kem is of the opinion that a stainless steel vessel is "usually" the more cost effective alternative when compared to a lined carbon steel vessel for water treatment applications. This assumes that the end user has the financial capacity to handle the higher upfront cost and that the vessel internals are properly designed. We added the word "usually" as the possibility of stainless steel chloride corrosion can be problematic in high temperature applications or those with improperly designed vessel internals.

Used with properly functioning internals, stainless steel vessels will last for a very long time on a simple water softening application. A carbon steel vessel on the other hand is very much dependent on the condition of the vessel lining. Eventually every lining will develop a pin hole failure leading to corrosion, a subsequent leak, and full vessel failure. Obviously this is not a concern with unlined vessels constructed of stainless steel.

In the case of the corrosion of the existing stainless steel vessels at this customer, there are two explanations for the corrosion they are experiencing. For starters they are not diluting the regenerant brine. This only increases the chloride levels during the regeneration cycle. It's worth mentioning that ordinarily any water softener is only subjected to high chloride levels during the 30 minutes or so as brine is introduced to the vessel. At this customer, not only is the brine saturated, but there is little assurance that the design of the internals gets all the brine out during the following rinse steps. Should this be the case, the bottom dome of the vessel would have a stagnant brine solution remaining in it well after the regeneration cycle is finished. This would particularly enhance the corrosion process especially if the water contains an appreciable amount of dissolved oxygen. One can only assume this condition applies at this customer and things are exacerbated with the higher concentration of brine being used.

It's worth pointing out that General Water, the service DI arm of Res-Kem has a rental fleet of well over 200 skid mounted DI exchange vessels. All are 36" diameter and all are constructed of stainless steel. The decision to purchase stainless vessels over lined carbon steel was not done because we like to spend money. It was done as it's a good investment over the long haul.

How to Measure pH Accurately in Steam Condensate

Keeping within ASME guidelines for total iron in boiler feedwater below 0.1 ppm and total copper below 0.05 ppm copper requires attention to the maintenance of steam traps, knowledge of the metallurgy of the steam/condensing equipment in the steam distribution system and in particular the pH of return condensate.


When measuring pH in condensate, it is important to cool the sample with an in-line water sample cooler to minimize the CO2 flashing off from the sample. When the CO2 flashes off it is not present in the condensate sample so it will not form carbonic acid. Without carbonic acid present, the pH will be measured with a false high pH. The difference between in-line cooled condensate samples and ambient cooled condensate temperatures can be 2.0 or more pH units. This difference in pH will dramatically increase the corrosion rate.

The following chart shows how equipment with large steam demands and therefore condensate flow with elevated CO2 levels will likely have elevated corrosion rates.


In addition to ensuring proper measurement of pH, an in-line water sample cooler enables safe handling of the high temperature condensate. Water sample coolers are available in carbon steel or stainless steel. Certain sample cooler models have easily accessible coils that can be cleaned or replaced as needed.

Uniform Particle Size Ion Exchange Resins

We received notice today that Purolite Ion Exchange Company will no longer be selling the anion resins, A-300 and A-400. These resins will be replaced by Purofine PFA-300 and PFA-400. The Purofine line of resins is uniform particle size (UPS). Dow did this a number of years ago when they introduced the Marathon grade of Dowex Ion Exchange Resins. The Marathon line of Ion Exchange resins pretty much replaced the entire line of standard Gaussian resins.

In general there are many advantages to using UPS resins.

Higher Regeneration Efficiency:
According to Dow regeneration is the least efficient step in the ion exchange process. Large beads regenerate more slowly than small beads. The typical Gaussian mesh range is 16-50 whereas UPS resins are 30-40 mesh, a much tighter specification. The UPS resins have a smaller average particle diameter and will regenerate more quickly resulting in more efficient use of regenerant chemicals. So you use less and get a higher operating capacity.

Greater Operating Capacity
The kinetics of the UPS resins is more favorable than that of Gaussian. "This leads to an increase in usage of the entire resin capacity from the top to the bottom of the bed...the net effect of the more efficient regeneration....is higher throughput."

Better Rinse Efficiency:
Excess regenerant chemicals diffuse more quickly from within the beads, thus decreasing the time required to reach the specified endpoint. Faster rinse times trim water and wastewater disposal costs.

Reduced Leakage:
The result of these increased efficiencies is an increase in production of pure water for a longer time since the leakage endpoint is extended

Better Separations for Mixed Beds:
For many years now Res-Kem has been advising customers to use UPS resins in their mixed bed units. In fact, our sister company, General Water Services, uses UPS resins to service their high-purity customers. One reason for doing so is better separation prior to regeneration. With Gaussian resins, the smaller cation beads are easily trapped with the larger anion beads. With better separation you get lower leakages, a better regeneration and greater throughput.

Operating Considerations:
Backwash Rates are lower when using UPS resins. Consult the engineering graphs, Dow Marathon, Purolite Anion or Purolite Cation, prior to installation or contact a qualified equipment manufacturer to determine the changes required when upgrading to Uniform Particle Size resins.

Helpful Links:
I've included a couple helpful links from Dow and Purolite with more detailed information if you'd like to read more about the advantages of using UPS resins in your water treatment system.

Here is information from Dow:
UPS (Uniform Particle Size): The Key to Greater Productivity in Ion Exchange

Here is information from Purolite:

Notice of Product Replacement for Purolite® A300 and A400

Setting Brine Tank Refill Time on Fleck Softener Valve

The Pentair^® Fleck^® multi-port softener valve controllers, electronic versions SE, XT, XTR and SXT and non-electronic versions, are very flexible allowing for customization of the regeneration cycle of the water softener. This flexibility requires that you know a little bit about the system and a simple calculation -"Brine Refill Time". Although a simple calculation, "Brine Refill Time" is often misunderstood.

Definitions:
The "Brine Refill Time" is easy to calculate and is the same regardless of valve and controller type.

The following values are based on the design of the softener and valve.

T = Brine Tank Refill Time (minutes)
X = Brine Line Flow Control Rating (gpm)
Y = Salt Dosage sometimes called Regeneration Level (lbs/cuft)
Z = Amount of Resin in Softener (cuft)

In order to set the time you need to know the concentration of saturated brine

C = 2.6 lbs/gallon = Concentration of Saturated Brine

So the equation is:

T = (Y * Z)/(X * C)

Example:

X = 0.5 gpm
Y = 12 lbs/cuft
Z = 2.5 cuft

T = (12 * 2.5)/(0.5 * 2.6) = 23 minutes for brine refill step

Parts for Solo, Solomatic, Bruner, Brunermatic, Permutit, Aquamatic, Culligan HiFlow Multiport Valves & Others

Routinely, Res-Kem receives requests for quotes for water treatment systems and their replacement parts. One area that frequently needs explanation is replacement parts for multi-port valves including Solo^®, Solomatic^®, Bruner^®, Brunermatic^®, Permutit^®, and Aquamatic^®.

We get questions like:

Please quote the following.:

AQUAMATIC valves with 6 ports total. 5 ports are 3". One in the rear and 4 in cross form. The 6th port is 2", which is the regenerant inlet port.

The fluid flowing through the valves is composed as follows:

1) Hydrochloric acid (HCL) 32% at ambient temp.
2) Sodium Hydroxide NaOH (caustic soda) 50% at ambient temp.
3) Water at ambient temp.
4) Picture of valve attached.



Another Question:
I have a Kisco water softener system with Aquamatic Solomatic Valves. The model number of the system is TWSKOM-300. I need replacement valves. What can I do?

Res-Kem Solution:
As a service company, Res-Kem frequently comes across many different water treatment systems, which have Solo, Solomatic, Bruner, Brunermatic, Permutit and Aquamatic Multiport Valves as well as other manufacturers. Unfortunately, many of these valves and controls for the valves have been discontinued or parts are extremely difficult to find, (which may be due to industry consolidation), and those parts which are available are very expensive. The Res-Kem solution is to replace the multi-port valves with a "valve nest" and an appropriate control system.

A valve nest performs all the functions of a multiport valve using Aquamatic diaphragm, Keystone butterfly, or other valves as specified by the customer. Using a standard layout with flexibility to account for various tank sizes, a valve nest is a very cost-effective alternative to a multi-port valve.

Valve nests can be supplied in a wide variety of materials: Cast iron valves with steel piping, Bronze valves with copper piping, plastic valves with PVC piping, stainless steel valves with stainless steel piping. They can be adapted to filters, softeners, dealkalizers, demineralizers and deionizers.

Type II Anion vs Type I Anion: Ion Exchange Resin Analysis Yields Regeneration Savings

Res-Kem is a supplier of ion exchange resins from several vendors including Purolite. Res-Kem is often asked to diagnose a potential ion exchange resin problem. Depending upon the resin type, cation, anion, or mixed bed, cost and length in service, it may make sense to sample the resin and test for parameters that can identify what has caused the resin not to perform and a potential remedy.

Problem:
One recent example of the value of an ion exchange resin analysis are the results of two anion samples sent to Res-Kem. The customer was noticing:

More frequent regenerations

Increased chemical usage

Longer rinse times This resulted in a much higher cost to produce water for use.

They needed a solution.

Ion Exchange Resin Analysis Reports:

Ion Exchange Resin Analysis Report for Train A
Ion Exchange Resin Analysis Report for Train B

Discussion of Resin Analysis (Written by Ted Begg of Purolite):

Train A & B strong base anion resin analysis concluded the samples are Type II Strong Base Anions, equivalent to Purolite A300. Both samples exhibited dramatic loss in strong base capacity and severe organic fouling. Typical Type II anions will have 90% strong base capacity when new, however, it is not uncommon to see severe reduction to the levels observed, ~ 60%, when the resin is continually subjected to temperatures well in excess of 95 degrees F. Strong base capacity is responsible for silica removal. As this capacity is lost, throughput to silica break gets lower and lower with cost of caustic for regeneration steadily increasing. Given caustic is approaching $1000/ dry ton, lost throughput due to resin degradation comes at a very high cost.

The organic fouling noted is severe and is likely contributing to lost throughput and increased rinse volume (fast rinse). The organics on the resin pick up sodium during caustic regeneration, which slowly elutes off during the fast rinse. Therefore the increased rinse volume.

The Demineralization System:

This plant was designed to mix returned hot condensate to the finished water make up storage tank. This water is used for boiler feedwater and as well as for regeneration. While the heated water is beneficial for boiler feedwater, it is not good for regeneration of the anion resins. This water can approach and possibly exceed 130 degrees F. The Type II strong base anion resin temperature limit is stated by manufacturers at 105 degrees F, however, it is more prudent to maintain the limit to a maximum of 95 degrees F. Given the plant operating conditions and the condition of the anion resin, we recommended that the anion be replaced with a more temperature stable product. A Type I porous anion resin with uniform particle size distribution is recommended as a replacement. The product, PFA400, is stable up to 140 degrees F and is more resistant to organic fouling than the incumbent resin. In this case longevity of the resin will improve. The throughput capacity of PFA400 will approach the incumbent resin as well. Thanks Ted for the detailed discussion above of the analyses.

Our Conclusions and Observations:

The conclusion is using a Type II anion in place of a Type I, where low silica water is required and the system can run above 95 degrees F, is a misapplication for the reasons stated above which are:

Less stable at higher temperatures

Strong base sites break down more easily breakdown to weak base sites

Lower capacity for silica

So how does this misapplication happen? The selection of the ion exchange resins for a demineralization system generally occurs many years before a system is started up. Depending upon the perceived complexity of the water treatment system which includes the demineralization system, an engineering company may be specifying the demineralization system components including the resins as well as a whole host of other pieces of equipment. Then these specifications will be bid on by a short or long list of OEM's each of whom wants to get the job. Most will bid to the specs, but others may suggest a cheaper alternative.

One common area to shave money from the whole job is to skimp on the demineralization system in particlar the anion system. When lowest installed cost is the driver, sometimes Res-Kem sees equipment companies selling deionization systems using a Type II anion resin. The reason they promote the use of a Type II anion is the anion portion of the system is smaller. Because the Type II anion resin has about a 10% higher initial capacity than a Type I, the equipment needs 10% less of the expensive anion resin and the size of the anion tank is smaller. The end result is several months after commissioning and transfer of the equipment from the OEM to the user, the problems begin. By then, the low budget OEM will be on to their next project and will often walk away from your problem.

Res-Kem believes the moral of the story is work work with a knowledgeable OEM with experienced personnel who will recommend the best equipment for your application and will stand behind their equipment when installed.

Water Neutralization Saves $23,000 Annually

Res-Kem has published another white paper on water treatment. This next one is entitled "Bucking the Industry Trend… Simple Change to Water System Saves New Jersey Manufacturer $23,000 Annually"by Kevin Preising.

This paper details how the addition of an acid water neutralizer (5.5-6 pH) as a pre-treatment step to the Reverse Osmosis system saved over $23,000/year in downstream operation expenses at a New Jersey manufacturing plant. The acid water neutralizer, with an investment of less than $7,000 and operational and labor costs of only $700/year, has a Return on Investment of less than three months. While not a solution for all systems with reverse osmosis and high acidity, discussing neutralization with a qualified vendor can save Electrodeionization and/or Service DI operational expenses.

What is really interesting about this paper is it shows how a simple acid water neutralizer, properly applied, can save a considerable amount of money on operating expenses.

Having been in the water treatment industry for two decades, I have seen the trend in the water treatment industry towards more and more complex water treatment technologies and discounting past knowledge as old-fashioned. Often lost is a true understanding of water chemistry by some current "industry experts" and the simple, economic solutions to water treatment problems.

Please take a look and tell us what you think!

Activated Carbon: Mesh Size

We are often questioned about the differences between 1240 (12 by 40) mesh activated carbon and 830 (8 by 30) mesh activated carbon. The 1240 mesh activated carbon is smaller than the 830 activated carbon.

The screens or the mesh sizes are different. The 12 mesh screen has 12 openings per square inch 12 across and 12 down. The 40 mesh screen has 40 openings per square inch, 40 across and 40 down. Obviously the "holes" of the 12 mesh screen are larger than the "holes" of the 40 mesh screen. It follows that the holes on an 8 mesh screen are larger than 12 and 30 mesh holes are larger than 40 mesh holes.

If you would like a laminated card with this guide, contact Res-Kem.

As part of the manufacturing process the activated carbon companies pass the carbon through various screens to meet the specification.


So if you look at 1240 mesh activated carbon, it shouldn't have particles larger than 12 mesh or smaller than 40 mesh. The 830 mesh activated carbon shouldn't have particles larger than 8 mesh or smaller than 30 mesh.

What difference does this make to the user of the activated carbon? The most commonly used activated carbons for residential POE (point of entry) systems, commercial and industrial systems are 830 and 1240 mesh. We use 1240 mesh activated carbon because it has greater surface area and provides excellent chlorine and organics removal. Because the activated carbon filter acts as a mechanical filter in addition to removing chlorine and adsorbing organics, it will accumulate particles of dirt or crud at the top of the bed. An activated carbon filter is backwashed on a regular basis to remove this and prevent pressure loss across the bed.

In instances where the water contains more turbidity or crud, an 830 mesh activated carbon may be used. Having larger particle size than the 1240 activated carbon, the filter containing 830 mesh activated carbon won't need to be backwashed as often. However, as the particle size increases from a 1240 mesh activated carbon to an 830 mesh carbon, thereby decreasing the backwash flow rate, adsorption capacity will generally decrease.

When we specify an activated carbon it's important to know the water source. If it's city water or well water from a potable source, we can assume there is little if any turbidity and use of a 1240 mesh activated carbon will work well. If an industrial plant is taking water directly from a river or lake there may be disruptions to the clarification system that may cause excess crud or turbidity. In these cases we see the use of 830 mesh activated carbon.

Here is a full glossary of activated carbon definitions.

FILMTECTM BW30LE-440 and BW30LE-4040 RO Elements to be Discontinued

The Dow Chemical Company recently sent a discontinuation notice for the FILMTEC BW30LE-440 and BW30LE-4040 which have been an industry standard for many years. Dow will not take orders for the current LE elements after May 30, but will honor any orders on the books even if shipment is not until the end of the year.

The good news is FilmTec Corporation has developed a new Low Energy, LE, membrane. FILMTEC elements rolled from this LE membrane have the highest active membrane areas, and operate at lower pressure reducing operating costs.

FILMTEC LE-440i:
This RO membrane element replaces the FILMTEC BW30LE-4040 RO Element. The FILMTEC LE-440i has 440 square feet of RO membrane which is the highest active membrane area in the industry.

The FILMTEC LE-440i element:

Has 10% higher productivity than the FILMTEC BW30LE-4040

Operates at lower pressure

Maintains High Rejection

Minimizes operating expense

Reduces total cost to produce industrial, commercial, or municipal water

Incorporates iLEC^TM interlocking endcaps minimizes O-ring leaks which improves permeate quality

FILMTEC< LE-400 element:
This RO membrane element replaces the FILMTEC BW30LE-440 RO Element. The FILMTEC LE-400 has 400 square feet of RO membrane.

The FILMTEC LE-400i element:

Has higher salt rejection for better permeate quality

Operates at lower pressure

Minimizes operating expense

Reduces energy cost to produce industrial, commercial, or municipal water