Mcilvaine Insights


No. 124   October 30, 2019


Weekly selected highlights in flow control, treatment and combustion from the many McIlvaine publications.

·       Briefs

·       True Cost of Gas Turbine Inlet Filters

·       True Cost of Limestone FGD Recycle Pumps



The combust, flow, and treat (CFT) products and services markets will exceed $400 billion next year. The market has typically been segmented by McIlvaine on geographical end use. However, this analysis is based on where the profits are generated. India and Italy are major exporters of valves. Africa will enjoy a rapidly increasing market, but China will be one of the main beneficiaries in terms of CFT products and services. It is building complete power plants and mines and, in many cases, taking part ownership of them. The market in 2030 is likely to rise to just under $600 billion if there is a lack of government interference. However, if there is interference in the markets the revenues could only rise to $535 billion. 

Effect of Interference on the Combust, Flow, and Treat Markets


Additional news you might have missed can be reached with the links below.


Would You Rather Share Sales Leads with Your Allies or with Your Competitors?


Sales Program based on the 500 Coal Plant Operators that buy 99 Percent of the Combust, Flow and Treat Products


Join the Debate on Insitu Rare Earth Recovery


True Cost of Gas Turbine Inlet Filters

The McIlvaine Company is working with associations, media and suppliers to create true cost analyses of combust, flow and treat products and services. One such initiative is the “True Cost of Gas Turbine Inlet Filters”.


The true cost of a gas turbine inlet filter can be affected by a large number of factors. These factors are not constants but are changing. The filter purchaser is challenged to not only identify these factors but to keep up with the changes.


Large gas turbines are used to generate electricity by utilities. Smaller gas turbines drive pumps and compressors in locations with extreme conditions such as desert dust, artic snow or sea spray on an oil rig. As turbines have become more efficient, they have become more susceptible to damage from contaminants in the combustion air.  This ambient air from the surrounding environment can contain high dust loads.  In California with very tight emission standards the particulate in the  inlet air to the turbine can exceed emission limits. Thus the gas turbine has to act as an air cleaning device.


The challenge for  gas turbine inlet fiber, media, and filter suppliers is to increase gas turbine availability in all environments with newer and more sensitive gas turbines. The newer turbine designs are negatively impacted by small particles.  This has led to the use of HEPA filters with efficiencies classed as H10/E10 and higher.  Studies show that turbine maintenance can be reduced with even higher efficiency E12-U17. One study showed that even if the cost of higher efficiency filtration were four times higher than lower efficiency filters, the true cost would be lower.


One can choose a system with non-cleanable filters. They are relatively inexpensive but require continuous filter replacement.  By using a sequence of inefficient but inexpensive pre filters and a final high efficiency filter, the replacement cost can be minimized.


An alternative is to use a cleanable filter. Periodic air pulsing knocks off accumulated dust.  These systems are available from many suppliers if the F-9 efficiency is all that is desired.  Cleanable filters with H12 efficiency are available from only a few suppliers.  On the other hand there are many new developments which will expand the number of choices.


In terms of high efficiency dust capture mechanisms there is a choice between wet laid glass and synthetic nanofiber non-woven laminates or membranes. The traditional glass media for HEPA filtration has been used primarily in non-cleanable filters.


Quantifying the benefit is a balance between reduced fouling and increased pressure drop. The increased pressure drop can be estimated to restrict performance by approximately 0.4%, while cutting fouling provides a 1.2% improvement in output (empirical average). Therefore, the overall result is a potential efficiency improvement of 0.8%.


Alliance Pipeline believes that the E12 filters from Gore may allow Alliance to extend the interval between overhauls of its aero engines from 25,000 to as many as 50,000 hours (from three to six years).


The many factors and media choices impacting gas turbine inlet filter selection  have been discussed in a background document on display at


In the past the most efficient filters which were used on gas turbine inlets were rated F-9 with efficiency of more than 95% on particles 0.4 um diameter.  The most penetrating particle size is about 0.2 um where the efficiency is much lower.  Higher efficiency filters are rated based on the most penetrating particle size as follows.


HEPA Class

Retention (total)


> 85%


> 95%


> 99.5%


> 99.95%


> 99.995%


> 99.9995%


> 99.99995%


> 99.999995%


Membrane laminates such as used for dust collection can meet efficiencies up to E12.  The question is whether this is sufficient?


There are a number of new filter and media designs which need to be evaluated.  Mann & Hummel Vokes introduced the Aircube Pro Power S which utilizes a new synthetic base media with much higher resistance to mechanical stress than glass fiber media and a stable high efficiency during operation. It is water and salt repellent while being extremely robust.

DHA filter has introduced a cleanable HEPA filter for gas turbine inlets which it will be displaying at PowerGen


The Guide to True Cost of Gas Turbine Inlet Filters will be used to facilitate discussions at a number of events in the coming months. It will be used along with a tour guide on the subject at the  PowerGen exhibition in November. 

It will also be the subject of a discussion at FiltXPO which will be held in Chicago in February.


The Decision Guide is continually updated and included Gas Turbine and Reciprocating Engines  Decisions  It is free of charge to gas turbine and engine owners and funded through supplier subscriptions.


To participate in the True Cost of Gas Turbine Intake Filters contact Bob Mcilvaine at  direct 847 784 0013 cell 847 226 2391.

True Cost of Limestone FGD Recycle Pumps

The McIlvaine Company is working with associations, media and suppliers to create true cost analyses of combust, flow and treat products and services. One such initiative is the “True Cost of Limestone FGD Recycle Pumps”.


80,000 MW of limestone FGD recycle pumps will be purchased in India over the next three years. Over 1.5 million MW of these large pumps are continually being operated at power plants around the world. Their  true cost (total cost of ownership) is a substantial percentage of the true cost for electricity production. One reason is the choice of pump energy over fan energy.

 It can be argued that scrubbers using less recycling slurry but more fan energy are a better choice but the coal fired power industry has standardized on the spray tower type of limestone scrubber.  For a 1000 MW scrubber the recycled slurry will be as much as 200,000 gpm  delivered to the top of a spray tower at a 50-100 ft elevation. This slurry is an abrasive, corrosive combination of gypsum, calcium sulfite and limestone particles along with some residual flyash.  The pumps are expected to remain functional for 20 years or more.

The true cost of the pump purchase is impacted by many factors

·       System design:  the piping design, pump location, valve resistance, spray tower nozzle type, chloride bleed provisions, requirement for spares and other factors

·       Pump design including initial efficiency, deterioration characteristics, and pump characteristics

·       Energy consumption for the new pump and during the cycle prior to repair

·       Cost of energy

·       Cost of repair parts and frequency of replacement

·       Cost for service

·       Operational factors such as maintenance quality, hours of operation per year etc.

·       Downtime costs

·       Labor rates

·       Related costs such as greater use of limestone or treatment chemicals with varying pump performance

India has adopted specifications with minor modifications which were first written decades ago for projects in the U.S. or Japan. A recent BHEL specification for an FGD system in Bangladesh Is for two generators each 660 MW and each unit with one FGD system. Each FGD system will be provided with five recirculation pump (4 working + 1 standby) which are located inside the Recirculation Pump & Oxidation Blower House.

The specifications for the recirculating pump allow for rubber lining, stainless alloys or silicon carbide materials in contact with the sulfite slurry with a maximum of 27,000 ppm chlorides.

This worldwide standardization of scrubber designs and pump requirements means that there is ample evidence of true cost of the various pumps which have been utilized and the ability to project true costs for future installations.


True cost is impacted by the location where the pump is manufactured and the location where the pump is repaired. It is also impacted by the service personnel proximity and the option for remote monitoring and support.

Libra Fluid Equipment Co., Ltd is home based in China. It was founded in 1999 and provides pumps and parts for various industries. It  supplies pump parts for any pump where the patents have expired.  It supplies ceramic, alloy and rubber lined impellers. This has true cost implications. The true cost of a pump purchased from any company without recently patented parts may be reduced with the option of purchasing parts from others such as Libra.

Parts and repair is a major true cost factor. Duechting Pump manufactures pumps in Germany but has regional service centers around the world. Is the true cost greater or the same for pumps supplied in the U.S and Asia?

KSB is a German based company but purchased GIW and manufactures pumps in the U.S.  

Trillium has multiple manufacturing and service locations.

Suppliers are being asked to provide true cost analyses which will be published in Coal Fired Power Plant Decision  This is a service which is free of charge to utilities around the world.

The service already includes recorded webinars and case histories of FGD pump performance compiled over decades. The Utility Tracking System identifies every FGD system in the world and includes the pump supplier for many of them.

This is a continuing process. As suppliers gain additional evidence it can be incorporated. The process is likened to a criminal trial where the supplier is the prosecutor and the jury is the purchaser. The difference is that the jury is periodically asked to review its decision based on new evidence such as life of impellers and casings in this recent case history.

The scrubber recycle pumps in this plant have operated at a flow rate of 1,310 cubic meters per hour (m3/h), 21.1 meters (m) of head and 630 revolutions per minute (rpm) for nearly 20 years, requiring minimum attention and service. Of course, the mechanical seals were exchanged from time to time. Apart from that, four impellers, one casing cover and some minor components were replaced. An additional 24 pumps are installed in the second scrubber system and other applications in the plant.

There should be separate true cost analyses for each location.  It is particularly important to analyze the cost in India.  A good example is the analysis by SHI FW relative to wet vs dry scrubbers for Indian power plants.

Sumitomo SHI FW has made a detailed analysis comparing CFB scrubbers to wet limestone scrubbers without wallboard quality gypsum production. 

The  lower quality of limestone available, the expected 15-year life for the older plants to which the system may be applied, and the much lower capital cost of the CFB design are key aspects in the determination. Here are the factors and calculations for a 300 MWe  pulverized boiler contained in the linked paper.

The analyses are being pursued with personal discussions including  at the upcoming PowerGen in New Orleans - There will be a PowerGen University half day session on Monday where McIlvaine will advise suppliers interested in reaching the international market to prepare detailed true cost analyses of their offerings. There will also be a tour guide. Speakers, exhibitors, and attendees interested in FGD recycle pumps will be listed in the directory with emails and mobile phone numbers to facilitate discussions during the conference.

For more information on Coal Fired Power Plant Decisions click on

To participate in the True Cost of Limestone FGD Recycle Pumps  contact Bob McIlvaine at  direct 847 784 0013 cell 847 226 2391.

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