MEMORANDUM 

TO: Ron Jordan, EPA 

FROM: Kurt Blohm, ERG 

 Sarah Holman, ERG 

DATE: 6 January 2010 

SUBJECT: Notes from EPA Conference Call with United Conveyor Corporation 

On December 10, 2009, EPA’s Office of Water/Engineering and Analysis Division (OW/EAD) 

held a conference call with United Conveyor Corporation (UCC) to discuss the design and 

operation of dry ash handling systems at power plants. The following people participated in the 

conference call: 

EPA 

Ron Jordan 

United Conveyor Corporation 

Kevin McDonough, Director of Marketing 

Dan Charhut, Vice President of Sales and Technology 

ERG

Deb Bartram 

Kurt Blohm 

Sarah Holman 

This memorandum details the topics that were discussed during the call. 

EPA’s Introduction 

 EPA went over the main objectives of the conference call for the call participants 

and introduced the Steam Electric Effluent Guidelines (ELGs). 

 EPA stated that the Steam Electric ELGs are expected to be proposed in mid-2012 

and finalized in early 2014. EPA explained that the Steam Electric Information 

Collection Request (ICR) is currently in the 1st Federal Register Notice (FRN) 

public comment period and encouraged UCC to review the draft questionnaire, 

particularly Part C (Ash Handling), and provide EPA with feedback. 

 EPA stated that it has visited power plants that have installed dry ash handling 

systems that were designed by UCC and noted the Karn/Weadock plant. UCC 

mentioned that the Monroe ash handling system is a mixture of UCC equipment 

and other vendors’ equipment. During the conference call, ERG emailed UCC 
Memorandum 

January 6, 2010 

Page 2 

the weblink for EPA’s Final Detailed Study Report (DSR), which lists the plants 

that EPA visited during the detailed study, as well as the weblink for EPA’s draft 

questionnaire. 

Ash Handling Discussion 

UCC’s Operations and Industry Trends 

 ERG asked UCC to provide an overview of their involvement in the ash handling 

business. UCC stated that they are a global corporation with 500 employees 

worldwide. The majority of UCC’s business is in North America. UCC stated 

that it has approximately 50 to 60 percent of the market share for ash handling 

systems (wet and dry, bottom ash and fly ash) in North America, 10 to 15 percent 

of the market share in Europe, and five percent of the market share in India. 

 ERG asked UCC to describe if and how the ash handling market is changing in 

the United States. UCC stated that, in the United States, dry fly ash handling 

systems have been around for several decades and are now installed on nearly 

every new generating unit. UCC estimated that two-thirds of all power plants 

handle their fly ash dry. UCC stated that between 60 and 90 percent of coal-fired 

power plants has some variation of wet bottom ash handling. UCC stated that they 

expect the number of plants installing dry fly and bottom ash handling systems to 

continue to increase, especially if regulations on ash ponds and ash sluice 

wastewater continue to tighten. 

 UCC stated that the most significant driver for the industry to switch to fly ash 

handling systems was the increased use of Powder River Basin (PRB) coal in coal 

blends, which began in the early 1980s. UCC stated that fly ash from PRB coal 

combustion contains approximately 25 to 30 percent calcium oxide, which causes 

plugging in wet sluice piping. Because of the high maintenance costs of 

unplugging the sluice piping, it became more cost effective for plants to install 

dry fly ash handling systems. 

 ERG asked why the steam electric industry did not also shift towards dry bottom 

ash handling in the 1980s. UCC stated that switching to dry bottom ash handling 

has been a lower priority for plants. UCC stated that PRB coal produces less 

bottom ash than bituminous coals, and that PRB bottom ash systems have fewer 

operational issues. [QUESTION FOR UCC: What “operational issues” are meant 

by this?] 

Bottom Ash Handling 

 UCC stated that it sells two bottom ash handling1 options that eliminate the need 

to store ash in ponds or impoundments: dewatering bins and the mechanical 

 

1

 “Wet” and “dry” are not well-defined terms when used to describe bottom ash handling. Often, the term “wet 

bottom ash handling” is used to refer to a system that sluices the bottom ash away from the boiler to a settling pond 

or a dewatering bin. “Dry bottom ash handling” is often used to describe a system that does not sluice the bottom 
Memorandum 

January 6, 2010 

Page 3 

submerged flight conveyor (SFC) system. UCC has been selling SFC systems 

since 1990. 

 UCC stated that dewatering bins can be operated such that all sluice water is 

recycled. EPA inquired about the purging necessary from dewatering 

bin/recirculation systems. UCC stated that often due to the evaporation that 

occurs and the fresh makeup water added to the system, plants only rarely need to 

purge these recirculation systems (e.g., during outages once every three years). 

UCC also stated that in their experience, pH control systems are only very rarely 

necessary. 

 UCC stated that SFCs use less water and energy than hydraulic systems (ash 

ponds and dewatering bins) and can achieve zero discharge of wastewater. EPA 

asked UCC to describe how SFC systems can be operated as zero discharge 

systems. UCC stated that some water leaves the system with the bottom ash, 

which is typically 18 to 20 percent moisture. UCC stated that the water added to 

SFC systems is used to keep the temperature of the water-filled chamber below 

the boiler (i.e., the water bath) below 140 °F. UCC stated that SFC systems may 

use several hundred gpm of water to cool the bottom ash; however, this water 

may be recirculated completely so that the system achieves zero discharge. 

 UCC stated that they sell two bottom ash handling systems that are considered 

completely dry systems: the Pneumatic Ash Extractor (PAX), and the Vibrating 

Ash Extractor (VAX) systems. The PAX system collects and crushes the bottom 

ash that falls from the boiler in a dry hopper where it is fed into a vacuum system 

that pneumatically transports the crushed ash to storage. The VAX system uses a 

vibratory conveyor to carry the bottom ash away from the boiler. Both the PAX 

and VAX systems return heat to the boiler to improve thermodynamic efficiency. 

 UCC stated that dry bottom ash handling systems are very prevalent in Asia and 

Europe. UCC stated as of about five to six years ago, China handles all of its 

bottom ash dry. UCC stated that European countries handle approximately 50 

percent of their bottom ash dry, India handles about 10 percent of its bottom ash 

dry. Literature on the UCC website estimates that only 10 percent of bottom ash 

systems in the United State are dry handling systems. UCC stated that nearly all 

(98+ percent) of plants should be able to convert a sluicing bottom ash system to a 

SFC, PAX, or VAX system. Those plants unable to make the conversion would 

be able to convert a pond-based system to a recirculating system that employs 

dewatering bins. 

 UCC stated that SFC systems have been the most popular because they have the 

lowest capital cost. UCC stated that in China, power plants often have an extra 

SFC system on site so that they can replace a non-functioning SFC system 

 ash with water, instead using conveyor or other systems to carry the ash away from the boiler. As used in this 

memorandum, the term “dry” includes completely-dry systems that use no water at all, as well as systems that 

employ water-filled hoppers to capture and cool the bottom ash before carrying it away from the boiler in a nonsluicing process. 
Memorandum 

January 6, 2010 

Page 4 

without any downtime; however, in the United States, that is not done due to the 

safety hazard of operating with an open boiler. Additionally, many boilers in the 

United States are several decades older than boilers in Europe and China, and may 

be more likely to cause the flight chains of SFC systems to break due to slag falls. 

UCC stated that in the United States, slag falls are often a result of burning poor 

quality coal in older, less efficient boilers. Many power plants in the United States 

choose not to install new bottom ash handling systems because they are resistant 

to trying new technologies out of concern they may cause significant downtime. 

 ERG asked if parasitic electricity consumption is a main factor that power plants 

consider when deciding which bottom ash technology to install. UCC stated that 

parasitic electricity consumption is a factor for many plants, but that it is 

considered more in Europe and Asia than in the United States. In the United 

States, the main factor is whether or not the bottom ash handling system will 

cause reliability issues that result in boiler downtime. 

Fly Ash Handling 

 ERG asked UCC to identify the main factors that either motivate a plant to install 

or negatively affect a plant’s ability to install/convert to a dry fly ash handling 

system. UCC identified the following as the main factors: 

o The type of coal burned (conversion to subbituminous coal spurs installation 

of dry fly ash handling); 

o Space available/distance required from particulate collection (ESPs or 

baghouses) to silos; and 

o Cost of disposing the fly ash (if landfilling fly ash) and transporting the ash 

from the silos, and revenues gained (if marketing fly ash). 

 UCC estimated that two-thirds of power plants operate dry fly ash handling 

systems, and that 30 percent of power plants that handle their fly ash dry are able 

to market the ash. 

 UCC stated that as the distance required to transport fly ash from the ESP hoppers 

to the silos increases, so does the cost of the transfer system due to the extra 

piping and the blower horsepower required to transport the ash; however, the cost 

increase is not linear. The most significant cost of the ash handling system is the 

silo. UCC stated that it is installing a dry fly ash handling system at TVA’s 

Kingston plant, and that this system required a vacuum/pressure transfer station 

and high capacity blowers. 

 ERG asked if there is a limit to the distance the fly ash can be transported 

pneumatically. UCC stated that when the distance to storage is more than two 

miles, there may be more cost-effective ways than pneumatic conveying to 

transfer the fly ash. UCC discussed another fly ash handling technology called 

dense slurry conveying, which can transport ash over a distance of several miles. 

In dense slurry conveying, ash is mixed with water to form a 70 percent ash, 30 

percent water mixture, which has the consistency of wet paint. This dense slurry 

ash is pumped at high pressure (1000 psi) to storage. UCC noted that no free 
Memorandum 

January 6, 2010 

Page 5 

water is emitted from the dense slurry conveying process. UCC stated that dense 

slurry conveying is popular overseas, and is beginning to be used in the United 

States, for example, at the JEA Northside Generating Station in Jacksonville, FL, 

which successfully transports ash six miles using dense slurry conveying (from 

fluidized bed boilers that burn coal and petroleum coke). UCC stated that the 

Florida DEP approved the dense phase slurry conveying at Northside in 2001. 

UCC also noted that AEP considered dense slurry conveying, and UCC offered to 

provide EPA with the contact information for Kevin Munson, the best contact 

person for the AEP project. UCC stated that at Northside, the ash is landfilled 

until it hardens, at which point Northside trucks the dried fly ash off site to be 

used as roadbed material. UCC stated that Northside evaluated several options 

and determined that dense slurry conveying was the most economical option. 

UCC noted that with dense slurry conveying, plants do not need to build roads, 

operate trucks, or obtain air permits, as they do with dry ash handling systems. 

 UCC stated that plants that operate old boilers will typically have two silos, one 

for unmarketable (“waste”) fly ash and one for marketable fly ash. Plants may 

have “in-line” control equipment that monitors the quality of the ash and 

automatically fills one silo or the other, depending on the level of quality. UCC 

stated that plants typically monitor the carbon content and size distribution of the 

ash. UCC stated that unmarketable ash is conditioned with water (typically to 15 

percent moisture), loaded in trucks, and landfilled. UCC stated that most silos 

have the capability to load fly ash dry and also the capability to condition fly ash. 

UCC stated that most plants will choose to install two silos for redundancy, 

regardless of whether they separate the ash based on quality. UCC also 

mentioned the Separation Technology, Inc. (STI) fly ash beneficiation technology 

that electrostatically separates carbon from fly ash, and that the separation 

equipment can be located underneath fly ash storage silos. 

 UCC stated that injecting activated carbon for mercury control affects the quality 

of the ash due to the increase in the carbon content of the ash. UCC stated that 

injecting the activated carbon downstream of the ESPs will prevent this problem. 

 ERG asked UCC to describe its experience with ash beneficiation technologies. 

UCC stated that they are aware of ash beneficiation technologies, but they haven’t 

been directly involved with them. UCC noted that cement manufacturers only 

accept fly ash with a carbon content of less than six percent. UCC stated that they 

do not believe carbon burn out is a feasible option for most power plants. UCC 

stated that carbon burn out is only feasible for plants that produce ash with a very 

high carbon content, in which case the carbon burn out facility can recycle 

sufficient heat back into the steam electric plant to improve the overall efficiency 

of the power plant. 

Cost Information and Concluding Discussion 

 ERG asked if UCC would be willing to provide any information that might help 

EPA develop a cost model for predicting the cost of converting to dry fly/bottom 

ash handling, including any system component costs UCC would be willing to 
Memorandum 

January 6, 2010 

Page 6 

share. UCC stated that a cost model based on system components has the potential 

to be overly complicated and risks being inaccurate due to site-specific variations. 

UCC mentioned the following major site-specific factors: 1) if the plant can 

market ash, 2) headroom available for equipment installation, 3) silos required, 

and 4) storage requirements in the silos. UCC suggested that EPA use a simpler 

model, such as one that correlates electric generation capacity at the plant (MW) 

to dry ash handling system cost (e.g., for a 200 to 300 MW plant, and a 500 to 600 

MW plant). 

 ERG stated that EPA’s cost models must be of sufficient detail for a rulemaking 

and noted that the Steam Electric questionnaire is set up to obtain this detail. EPA 

stated that UCC’s input on EPA’s questionnaire would be helpful to ensure that 

EPA obtains information on the critical cost elements/factors. 

 ERG asked if UCC has any cost curves that it would be willing to share and UCC 

stated that they could supply some budget information. UCC provided the 

following system costs estimates for EPA and ERG based on a 600 MW electric 

generating unit: 

o Dry fly ash handling system conversion (including silo costs): 

 Equipment costs: $7-10 million 

 Installed costs: $14-20 million 

o Dry bottom ash handling system 

 Equipment costs: $3-5 million 

 Installed costs: $10 million 

 UCC stated that any successful cost model would need to take into account the 

appropriate economies of scale. For example, power plants converting multiple 

generating units to dry fly ash handling systems would not necessarily need more 

silos than that for one generating unit. UCC noted that a plant will likely have 

two ash storage silos if it is operating four generating units. UCC stated that 

similarly, power plants installing dewatering bins for multiple generating units 

could install one large dewatering bin rather than multiple ones. As an example, 

UCC mentioned that the Kingston plant installed a dewatering bin system for its 

nine generating units because it was more cost effective than installing individual 

dry bottom ash handling systems on each of the nine generating units. 

 EPA asked UCC how the costs of all bottom ash handling options (including 

dewatering bins and ash ponds) compare in terms of their life cycle costs (i.e. 

capital and operation and maintenance costs). UCC stated that pond systems are 

almost never installed at new power plants because ponds have become expensive 

due to tighter regulations on liners and management practices. Therefore, the most 

cost-effective bottom ash handling options for new plants are SFC systems and 

completely dry bottom ash handling systems (VAX and PAX). UCC stated that 

VAX and PAX can increase the theoretical thermodynamic efficiency of the 

boiler by 0.25-0.50 percent due to the recovery of heat back into the boiler and the 

resulting increase in plant efficiency. This added efficiency makes completely dry 
Memorandum 

January 6, 2010 

Page 7 

technologies generally more cost-effective than SFC systems in the long-term, 

although the pay back period may be several years. 

 EPA asked UCC to compare the costs of all bottom ash handling options in terms 

of life cycle costs for plants that have pond systems. UCC stated that they 

performed a cost analysis ten years ago comparing the capital and operation and 

maintenance costs of wet pond systems to SFC systems. UCC stated that the 

analysis showed that, even if the plant has a pond system, SFC systems are still 

more cost-effective than wet ash handling from a life cycle perspective, in part 

because SFC systems do not require high pressure pumps. 

 UCC invited EPA to visit UCC’s Headquarters and technology laboratory in 

Waukegan, IL. UCC stated that they could put together presentations that would 

help EPA to better understand the technical detail of their dry ash handling 

systems. Additionally, UCC offered to meet EPA at some of the power plants at 

which they have designed dry ash handling systems. EPA stated that they are 

interested in meeting with UCC and will follow up with UCC. UCC stated that 

they would compile a list of all of the power plant sites at which they have 

intalled dry systems and would send this list to EPA. 

 EPA requested that UCC indicate if any information discussed during the 

conference call or provided in the future is considered confidential business 

information (CBI). EPA explained that UCC can claim certain pieces of 

information as CBI and that EPA would handle any CBI according to EPA’s strict 

CBI handling procedures.