Monday, October 27, 2008

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.
  • Wednesday, October 01, 2008

    Stainless Steel vs Lined Carbon Steel Vessels for Industrial Water Softeners

    Recently we received the following question from a prospective customer:
    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.General Water Stainless Steel 30 cubic foot Service DI Vessel