Project Name: Determine effective re-use of fly ash and coal dust from power plant.
Project Client: ICAST and Aquila Networks
Contact Client@ Ravi Malhotra
Executive Director, ICAST
Email: ravi@ic-ast.org
Ph: 303-984-1134
Website: www.ic-ast.org
Project Description:
Aquila Networks is the second largest investor-owned utility company in Colorado. They
operate a coal-fired power plant in Canon City that generates fly ash and bottom ash as waste
products that they cannot currently use. In fact, Aquila has to pay disposal fees to get rid of this
waste stream. In addition, the supply of coal currently burned at the plant contains a high level
of coal dust, which burns very inefficiently in the plant boilers and results in a very high carbon
content of the fly ash, typically over 40%.
The area around Canon City has large tracts of forest that are overstocked and in danger of
burning and being infested with beetle. Local forest rangers would like to remove the small
diameter trees and slash (branches, leaves, shrubs etc.) to reduce the danger of catastrophic fires
or beetle infestation. Currently, the forest service burns the excess growth in a controlled
manner to reduce the forest strand. Burning forests has its disadvantages: it creates pollution and
sometimes can go out of control. Also, local sawmills generate tons of sawdust as their process
waste and would like to find a beneficial use for it.
ICAST and Aquila Networks believe that an energy source can be created by combining the
power plant waste and coal dust with the forest and sawmill waste i.e. combining the fly-ash,
bottom ash, coal dust and sawdust. Briquettes made from this combination could be burned in
the power plant, thus eliminating a lot of waste and improving the plant efficiency. The other
advantage could be less pollution: briquettes typically burn more cleanly than either coal or
wood and so burning briquettes should reduce the amount of pollutants the power plant and
forest fires currently put into the atmosphere.
Also, if the coal dust could be separated from the larger diameter coal prior to combustion and
use, that coal dust as a component of the briquettes would boost the BTU content of the
briquettes and lower the ash loading in the bag houses and ash handling system. The cost of
separating the coal dust on the front end would have to be weighed against the present operation,
which is to run all the coal and dust "as delivered" through the boilers and collect the high carbon
fly ash on the back end.
As far as the client could find from a preliminary search, briquettes utilizing fly ash, coal dust
and sawdust have not been commercially produced before and so we do not know if:
1.
2.
3.
4.
Briquettes can be produced consistently from fly ash, bottom ash, coal dust and sawdust?
The economic viability of a production facility manufacturing such briquettes?
The amount of pollution prevention can they achieve?
Any other benefits of such an undertaking?
Dr. Kurt Mackes at CSU’s Forestry Dept. has produced briquettes in his lab, utilizing fly ash
with the coal dust from Aquila and locally available sawdust. He used cornstarch and plastics as
binders. Cornstarch is expensive but does the job consistently. Plastics (from recycled bottles)
also worked and actually increase the BTU content due to the ability of the plastic to burn, but
needed to be heated in the briquetting process (which in turn requires energy). Kurt will be
available to the team as a mentor and advisor (Email: kmackes@cnr.colostate.edu or Ph: 970491-4066)
The student team will work to find answers to the questions posed above. For this they will first
need to:
1. Research current briquette manufacturing processes and equipment and evaluate the
possibility of utilizing one of the current technologies for the production of the coal-wood
combination briquettes (the student team will provide the reasons for recommending one
technology over the others).
2. Research other options to reuse coal dust and fly ash from the plant. Compare economic
viability of these options against current disposal and briquetting.
3. Research current EPA pollution standards for coal and wood and the level of pollution
created currently by the Aquila coal-fired power plant (which may be specific to the type of
coal they use) and the burning of the wood by the forest service and sawmills. Also research
the resulting pollution (theoretical) by our combination briquettes.
4. Research the potential binders and optimal percent of the various ingredients that will be
required to create our combination briquette.
Describe a test plant by which a researcher could prepare prototype briquettes, using
various binders and percents of the various ingredients.
Test these prototype briquettes by burning them in an environment where their energy
content and pollutants can be measured.
Develop the optimal briquette(s) that can be manufactured consistently and which
produces the least amount of pollution
5. For the recommended approach, evaluate the technical and economic viability of establishing
a manufacturing operation in close proximity to the coal-fired power plant in Canon City.
6. Based on the results of the tasks above, recommend the best solution, in terms of pollution
levels, manufacturability and economic viability.
Scope of Work:
A. Overview project needs
B. Current Conditions
i. Overview of current power plant facility and operating permit
ii. Air pollution levels
iii. Analysis of fly ash and coal dust characteristics and quantities
iv. Fate of coal dust, fly ash, and associated costs
v. Quantities of waste wood and other compatible materials/processes locally
C. Future Conditions
i. Changes in energy output/demand/cost anticipated
ii. Changes in air pollution regulations anticipated
iii. Changes in waste disposal options/cost anticipated
D. Define Constraints and Criteria for the project
a. Meet with clients to develop these
E. Develop Alternatives
a. Briquetting
i. Typical materials
ii. Manufacturing
iii. Pollution
b. Other uses for fly ash
c. Other uses for coal dust
d. Include “status quo” as a comparison
F. Propose a research plan to quantify unknowns related to Alternatives
G. Recommend Best Strategy
H. Preliminary Design of Selected Strategy
-This should include waste collection equipment needed, design of processes, and site layout.
-Costs (Capital and O&M)
- Schedule
I. References
-Utilize industry standards for design such as EPA guidelines and peer reviewed documents
J. Written reports
The alternative evaluation will be submitted to the client for review. A revised alternative evaluation
(addressing comments from the Client) will be submitted with the preliminary design.
K. Project Management
-Appropriate project management should be provided throughout the study and should consist of the
following items, as a minimum:
-Complete work within budget limits and on schedule
-Provide appropriate quality control of the work
-Coordinate input from local personnel
Schedule
Draft alternative evaluation report – Oct. 28
Presentation: alternatives evaluation and preliminary design – Dec. 2-7
Final alternative evaluation incorporating client comments and preliminary design report – Dec. 9
Proposal
The consultant shall provide a written interpretation of the scope of work (the Proposal), emphasizing aspects of the
work requiring specific attention. Recommended revisions or additions to the scope of work and schedule based on
respondent's experience should be presented. Descriptions of specific tasks presented in the proposed scope of work
above should be expanded or modified to address any special considerations or approaches.
In addition, the respondent should provide a draft table of contents for the written reports anticipated to be
developed as part of the scope of work.
The following factors will be considered in the selection of a consultant for this study and design:
o quality of proposal in response to the Scope of Work presented above
o evidence of a understanding local stakeholders and their preferences
o overall firm experience
o quality of staff assigned to the project: experience with similar studies, design experience with similar
projects, breakdown of staff time assigned to project
o references
o cost
Presentation of the scope of work and workplan should be directed to Angela Bielefeldt on Sept. 16, 2004.
Provide a hard copy of the visual aids.