Study into the Utilization of Bio-Gas (Methane) for the Coors Brewing
A proposal submitted to the Integrated Science and Technology
Program at James Madison University in partial fulfillment
of ISAT - 491/492/493
under the faculty guidance of
External Sponsor: Warren G. Heidt, Principal Engineer
Coors Brewing Company, Shenandoah Brewery
April 6, 2000
Brian Kish __________
David Buck __________
Dr. Klevickis __________
Project Title: A Study into the Utilization of Bio-Gas (Methane) for the Coors
Team Members: Brian Kish and David Buck
Senior Project Faculty Advisor: Dr. Klevickis
External Sponsor: Warren G. Heidt, Principal Engineer Coors Brewing Company
Coors Brewing Company is currently using an anaerobic bulk volume fermenter
to treat their wastewater. Right now the fermenter is running between 60% and 80% of
design capacity in the winter months. This is due to lack of a system that controls the
fermenter temperature. Process efficiency begins to drop off at temperatures below 31 oC,
which results in the lower treatment capacity during winter months. Starting this
November, they are looking to increase production over the 1999 levels by 17%. Their
current process produces 7 million Btu/hr of methane gas, which they burn as waste.
Coors has investigated three ways to utilize the methane gas that is currently wasted
during the treatment process: a bio-gas boiler, an engine-driven air compressor and an
engine driven induction generator set. Previous interpretation of EPA regulations has
prevented Coors from implementing one of these processes. However, the current
political and environmental climate is favorable to proceed with a process modification
that will recover and utilize the waste bio-gas for a beneficial use. Due to the need to
better control the fermenter temperature, Coors has decided to add a bio-gas boiler. It has
been determined that the installation of an appropriately sized bio-gas boiler will
consume 3.34 million Btu/hr input. This will leave Coors with 3.66 million Btu/hr of
surplus methane. Our project will look at the cost efficiency of these processes
considering the expected future growth of the Coors plant.
The Virginia facility of the Coors Brewing Company has been operating since
1987. This facility is concerned with blending, finishing and packaging of Coors
products brought to the facility by railcars. The facility is located in Rockingham
County, Virginia between the Blue Ridge Mountains and the South Fork of the
Shenandoah River. Because of its close proximity to sensitive natural resources
including Shenandoah National Park, the area is designated as Class I pristine for
environmental permitting conditions. The South Fork of the Shenandoah River has been
designated by Virginia as Class IV (Mountainous Zone Waters).
Wastewater from the Coors facility is treated by anaerobic pretreatment with a
Bulk Volume Fermenter (BVF). The wastewater then undergoes treatment utilizing
conventional aerobic complete mix activated sludge for final polishing. The Bulk
Volume Fermenter, which was installed to more efficiently treat the wastewater at the
Coors facility, was officially declared in-service on September 6, 1995.
The BVF is a trapezoid in shape. It is 292 ft in length, 195 ft wide at the inlet and
97 ft wide at the outlet. The BVF is approximately 28 ft deep. Reinforced concrete
retaining walls surround the perimeter. It contains a synthetic geomembrane liner and
floating cover that make the unit completely gas and liquid tight.
The BVF needs to run at a minimum
temperature of 31oC for maximum efficiency.
Because of a lack of a system to control the
fermenter temperature the temperature of the
BVF currently drops below 31oC in the winter
months. As a result, the plant has a lower treatment Figure 2. The bulk volume fermenter at
the Coors Brewing Plant
capacity in the winter. The BVF produces methane gas that is currently burned as waste.
While previous interpretation of EPA regulations has prevented Coors from using the
excess methane for energy, the current political and environmental climate is favorable to
proceed with a process modification that will recover and utilize the waste bio-gas for a
The plant is planning to install a bio-gas boiler which will use the methane
produced by the BVF as fuel and heat the BVF to the required temperature. The bio-gas
boiler will use only about half of the available gas from the BVF. Because of this, there
will be enough surplus gas to provide about 3.66 million btu/hr of available heat energy.
There are several options the Coors plant is investigating to make use of the extra energy.
The first option is to install an engine driven induction generator. This would produce 65
KW of electricity per unit. It is estimated that five of these units can be installed with the
available amount of methane. These five units would collectively produce 325 KW or
7,800 KWH of electricity per day. The waste water treatment plant at the facility only
uses 2800 KWH per day so there will be a surplus of 5,000 KWH per day of electricity.
This extra electricity could be sold back to the Shenandoah Valley Electric Cooperative.
The main plant could also use it if a
power line was run across the street.
The second option is to install a
bio-gas engine driven plant air
compressor. This would solve the
problem of the high cost of running the
electric driven air compressors across the
Figure 2. This is an example of
street at the utility center. Two 250 HP an induction generator that
might be used at the Coors
600 SCFM air compressors would utilize Brewing Plant.
all of the surplus bio-gas that would remain after the boiler was installed. The air
compressors would be capable of providing over half the demand for the plant air at the
main facility. A pipeline would need to be constructed to deliver the 1200 SCFM of
plant air to the main distribution system. The initial capital cost of the compressors and
the pipeline to deliver the air back to the main facility is expected to be very high.
We chose to do our senior project at the Virginia facility of the Coors Brewing
Company, because it combines information we have learned from biotechnology,
environment and energy. We think the project will be a good opportunity to use what we
have learned in a real world situation. We are also interested in the fact that the Coors
plant was not allowed to utilize the energy from the burning of methane due to
environmental legislation, even though it would be beneficial to the environment.
The goal of our project is to look at the cost efficiency of utilizing the remaining
3.66 million Btu/hr of methane and to consider the expected future growth of the Coors
plant. First of all, they would like to operate the BVF at 90% efficiency during next
winter in order to accommodate a 17% increase in production volume. This can be
accomplished by adding a bio-gas boiler. The addition of a bio-gas boiler will leave
Coors with 3.66 million Btu/hr of methane available for other use. Secondly, the
expected growth of the plant will require them to build a second anaerobic BVF that will
produce additional bio-gas. The single 3.34 million btu/hr bio-gas boiler will be able to
handle an additional BVF. We will look at the cost benefits of adding a bio-gas engine
driven induction generator or a bio-gas engine driven plant air compressor. We will also
look at the DEQ regulations that impact these processes. We will discuss our findings in
an analytical report that will include a recommendation on what alternative process(s)
Coors should pursue for present and long term considerations.
Our research will center on maintaining a temperature of 31 oC in their BVF.
When the temperature of the BVF falls below 31 oC Coors looses the ability to produce
the amount of beer that they would like to and this causes Coors to loose revenue. We
believe that our research will show that adding a bio-gas boiler will allow Coors to keep
the BVF temperature above 31 oC in the winter months, even with a 17% increase in
utilization of the BVF. We will show this by investigating the proposed bio-gas boiler
installation. By looking at the cost of the installation and financial benefits of the
installation we expect to be able to calculate an initial rate of return (IRR) for the bio-gas
boiler. By investigating the regulatory issues that are involved in this process (form 7
registration with DEQ), we will explore issues such as the emissions controls that may be
required with this installation. Once we have solved this problem, we will then look into
utilizing the remaining 3.66 million btu/hr of methane.
The secondary problem that Coors will experience is how can the company best
utilize the remaining 3.66 million btu/hr of methane. We will investigate two possible
uses for this bio-gas. These options are the installation of a bio-gas engine driven
induction generator set and the installation of a bio-gas engine driven plant air
compressor. Both of these possible solutions will require us to investigate the DEQ
regulations involved in the installation of these options. This is a very important area
because Coors has previously experienced setbacks due to regulatory red tape. It will be
very important for us to complete a thorough investigation of this area. For this part of
the project we will consult with Dawn Gibbs or Sharon Foley from the DEQ. We will
also investigate the IRR of each of these options. Calculation of the IRR is a very
complicated process and will require us to investigate the initial costs of each option
along with the maintenance and operational costs as well as the financial benefits of the
project. Coors generally looks at an annual time period for financial justification of a
project of this nature.
Preliminary investigation of the bio-gas engine driven induction generator set has
shown that the generator sets can produce 65 KW of electricity per unit. If this turns out
to be true then Coors could install five of these generator sets with the remaining 3.66
million Btu/hr. These five generator sets could collectively produce 7,800 KWH of
electricity per day. The wastewater treatment plant only uses 2,800 KWH per day for all
of its processes. If these calculations prove to be in the ballpark (we expect they are),
then we will investigate the best way to utilize the surplus of 5,000 KWH per day.
These options include selling the surplus electricity back to Shenandoah Valley
Electric Cooperative (SVEC) or running a pipeline to the main plant and using the
surplus electricity at the main plant. This will require us to investigate whether or not
SVEC will pay enough for the surplus electricity in order to justify adding 5 generator
sets instead of two or if it will save Coors enough money to justify running a power line
across to the main plant. We will also have to investigate the DEQ emissions regulations
that will be required for each of these options and determine if that has any bearing on the
decision to install two or five of the generator sets.
Preliminary investigation of the installation of bio-gas engine drive plant air
compressor(s). Shows that they many be used to eliminate the high cost of running the
electric drive air compressors across the street at the utility center. Two 250 HP 600
SCFM air compressors could be installed at the BVF and provide over half of the demand
for plant air at the main plant facility. The initial capital cost of these air compressors
will be very substantial due to the high cost of the compressors and the cost of installing a
pipeline header from the waste treatment plane to the main facility. This pipeline will be
needed to deliver the 1200 SCFM of plant air to the main distribution system. For the
plant air compressors we will investigate the regulatory issues surrounding this option,
especially the DEQ requirements for permitting and emissions controls. We believe that
the regulatory issues may be less demanding for this option due to the fact that this option
is not a co-generation option.
We believe that our investigation into the utilization of the bio-gas at the Coors
Brewing Plant will lead us to determine the best way to handle this problem by first
addressing their current needs and then addressing their future concerns.
We believe that this project will give us valuable insight into the DEQ regulatory
process along with showing us how companies must continually modify their ideas in
order to comply with these regulations.
Common Wealth of Virginia Department of Environmental Quality. Permit Forms and
Instructions Persuant to Regulations for the Control and Abatement of Air Pollution.
This form Contains the forms need to apply for the bio-gas boiler air permit at the
CEC Consultants, Inc. Capabilities & Experience prepared for: Coors Brewing
Company. August, 1998.
This is a report prepared by CEC Consultants, Inc. on the benefits that an engine
driven induction generator set for the Shenandoah facility. This report mentions using an
engine driven induction generator set manufactured by Jasper Tech.
ADI Systems Inc. The Feasibility of Biogas Utilization at Coors Shenandoah Brewery
Elkton, Virginia. May, 1996.
This is a report completed by ADI Systems Inc, to investigate better ways to
utilize the wasted energy of methane generated by the BVF. In this report ADI Systems
Inc, proposes the installation of an engine compressor set.
ADI Systems Inc. Proposal Anaerobic Pretreatment for Coors Brewing Company
Shenandoah Brewery Elkton, VA. June, 1994.
This is another proposal for the installation of a BVF written by ADI Systems Inc,
to Coors Brewing. This proposal contains a process schematic, site plan, typical process
guarantee, equipment list, project schedule, organizational chart, price proposal, annual
operations and management cost estimate and a technical design including estimate of
reactor effluent characteristics and waste sludge quantities.
ADI Systems Inc. Revised Preliminary Proposal Anaerobic Pretreatment for Coors
Shenandoah Brewery Elkton, VA. March 1991.
This is a proposal written by ADI Systems Inc, to Coors Brewing, which proposes
the creation of an anaerobic pretreatment facility at the Shenandoah Brewery. This
proposal contains a preliminary flow schematic, preliminary site plan, typical process
guarantee, equipment list, preliminary schedule, organizational chart, capital cost
estimate, annual operations and management cost estimate and a technical design.
ADI Systems Inc. Anaerobic BVF Bench Scale Study. November, 1991.
This is a report summarizing a study conducted by ADI Systems Inc. This study
investigated the benefits of using a BVF to treat wastewater for the Shenandoah Brewery.
ADI Systems Inc. Design Builders of Wastewater Treatment Systems. June 9, 1999.
This is a correspondence written by ADI Systems Inc, to Warren Heidt. This
correspondence discusses the installation of a boiler system to utilize the wasted methane.
ADI Systems Inc. Fascimimle Message. Jan 14, 2000
This is a copy of a correspondence between Warren Heidt and ADI Systems Inc.
This correspondence contains detailed calculations for the bio-gas boiler air permit Form
Heidt, Warren G. Bulk Volume Fermenter Technology for Anaerobic Pretreatment of
Brewery Wastewater, 1996.
This is a report written Warren G. Heidt discussing the installation of the BVF at
the Shenandoah facility. This report also discusses the use of the BVF in its early stages
and the benefits this installation has brought and will bring to the treatment of wastewater
at the Shenandoah facility.