NOTE

SUBJECT: 	Analysis of Costs of Replacements and Repairs at a
Hypothetical 100 MM GPY Ethanol Facility 

FROM: 	Barry Garelick, Environmental Protection Specialist; Assessment
and Standards Division

TO: 		Docket EPA-HQ-OAR-2005-0161 

DATE:  	October 16, 2008

Based on discussions with companies that construct ethanol plants, we
learned that facility owners will make decisions about equipment
replacements and technology upgrades that will continue to improve the
overall operating costs and energy efficiency of the plant.  In
particular, energy-intensive processes in the plant are likely to be
replaced or upgraded to increase fuel and operating efficiency, thus
reducing operating costs of the plant, and increasing output.  In
addition, Nilles (2006) reports that the first line of next-generation
dry-grind ethanol plants was built with mild steel components and that
in 10 or 15 years, those components will need to be replaced
entirely—most likely with stainless steel.   Of particular importance
is that durable materials as well as weaker materials both require
maintenance and replacement.   As such, the components and equipment in
ethanol facilities are designed to be easily replaced and to allow
simple maintenance. 

Using cost data contained in the U.S. Department of Agriculture’s cost
estimation model for construction of new ethanol plants described by
Kwiatkowski, J. et al (2006), we calculated the cost of replacement of
specific components under two scenarios in a hypothetical 40 million
gallon ethanol facility.  In the first scenario, we assumed that all
steel tanks are replaced with stainless steel tanks with the exception
of the fermenters, and that only combustion unit replaced is the ring
dryer.  Under the second scenario, the fermenters are replaced along
with most combustion equipment.  

Table 1 shows the equipment and associated costs for both scenarios. 
Replacement costs were combined with ongoing maintenance labor and
supply costs at 2 percent of the capital cost of the facility.  The
facility was assumed to be a 100 million gallon per year ethanol plant,
and the installed capital cost of such plant in 2006 dollars is given by
the USDA model as $59.3 million.  Over 15 years, under the first
scenario, the accumulated costs of equipment replacement and ongoing
maintenance is 52% of the cost of the $59.3 million cost of a comparable
new facility.  For the second scenario, the accumulated costs are 74%.  

Table 1: Costs of Equipment Replaced in Each of the Two Scenarios

EQUIPMENT	Scenario 1	Scenario 2

	Cost ($000)	Cost ($000)

Meal Surge Tank	X	$92.2

Batch Weigh Tank	$144.3	$144.3

Continuous Weigh Tank	X	$123.1

Alpha Amylase Tank	$141.9	$141.9

Ammonia Tank	$81.4	$81.4

Slurry Mix Tank	$346.4	$346.4

Liquefaction Tank 	$414.7	$414.7

Cook Retention Tanks	$492.0	$492.0

Gluco Amylase Tank	$239.3	$239.3

Sulfuric Acid Tank	$53.6	$53.6

Saccharification Tank	$1,127.2	$1,127.2

Yeast Tank With Agitator	$336.5	$336.5

Fermentors	X	$7,084.8

Clean In Place Tank	$71.5	$71.5

50% Caustic Tank	$209.6	$209.6

Beer/Stillage Recovery Exch.	X	$1,298.2

Beer Column Tower	X	$795.7

Beer Column Reboiler	X	$1,738.4

Stripper Col Reboiler	X	$804.6

Yeast Tank With Agitator	X	$336.5

Fermentors	X	$7,084.8

Clean In Place Tank	X	$71.5

50% Caustic Tank	X	$209.6

Beer/Stillage Recovery Exch.	X	$1,298.2

Beer Column Tower	X	$795.7

Beer Column Reboiler	X	$1,738.4

Stripper Col Reboiler	X	$804.6

Whole Stillage Tank with Agitator	$559.0	$559.0

Thin Stillage Tank with Agitator	$650.6	$650.6

Process Condensate Tank	$260.8	$260.8

Ring Dryer	$6,678.8	$6,678.8

Denaturant Tank	$96.9	$96.9

Ethanol Day Tank	$263.3	$263.3

Ethanol Product Storage Tank	$872.5	$872.5

Steam Boiler System, Deaerator & Pumps	

X	$2,038.5

TOTAL	$13,040	$26,196



  Nilles, D. 2006. “Time Testing”;  Ethanol Producer Magazine, May,
Vol. 12, No. 5

  Kwitakowski, J.R., McAloon, A., Taylor, F. Johnson, D. 2006. 
“Modeling the process and costs of fuel ethanol production by the corn
dry-gring process.”  Industrial Crops and Products 23 (2006) 288-296.

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