Energy Conservation
Preventive Maintenance
Industrial Boilers
2,400 BHP
600 BHP
200 BHP
50 BHP
Capital Cost vs Operating Cost
Source: Steve Connor, 2010
Boiler Energy Balance
http://www.energysolutionscenter.org 3/9/08
Energy Efficiency
Source: Steve Connor, 2010
Types of Boilers
Firetube - Dry-back
Firetube – Wet-back
Watertube
Electric Boiler
http://www.spiraxsarco.com/resources/, 3/1/08
Energy Savings – Boiler Type
 The cost to operate a boiler is 4 times the
initial installation cost.
Boiler
Efficiency
Oil
$2.75/gal
Natural Gas
$1/therm
Base Operating
70%
$1,400K/yr
$717K/yr
75%
-92K
-48K
80%
-173K
-89K
85%
-245K
-126K
Assuming 500 BHP @ 3000 hrs/yr
Energy Savings - Scaling
Boiler Water
Scale
Tube Metal
Hot Gases
metal = good conductor of heat
scale = poor conductor of heat
Modified Dale Williams, 2006 Chem Treat
Energy Savings – Scaling
Scale Thickness
(Inches)
Additional Fuel Usage
(Percentage)
1/32
8.5%
1/25
9.3%
1/20
11.1%
1/16
12.4%
1/8
25.0%
1/4
40.0%
3/8
1/2
55.0%
70.0%
Example - $750K fuel bill with 1/16” scale cost $93K.
http://www.energysolutionscenter.org 3/9/08
Energy Savings - Economizer
 Example – 500 hp Boiler
 20,000,000 BTU
 5% recovered with
economizer
 1,000,000 BTU’s
 Water returned to boiler
http://www.energysolutionscenter.org 3-5-08
Boiler Blowdown - Why do we blowdown?
 To remove the dissolved solids that have
concentrated in the boiler due to evaporation
Too Much Blowdown
• Increased fuel costs
• Increased water costs
• Increased chemical costs
Too Little Blowdown
• High TDS will occur, resulting in:
• Foaming
• Priming
• Corrosion
• Scale
PURE WATER
SOLIDS
Energy Savings – Blowdown Heat Recovery
TDS Monitor
 Blow down is 5-10%
of boiler capacity
 Recovery systems
can capture steam
that would go to the
drain
 Pre-heat make up
water
 Reduces water usage
to cool the blow down
prior to the drain
http://www.energysolutionscenter.org 3-5-08
Energy Savings – Steam Traps
Example: 52.8 lbs/hour x 8,760 hours per year x $9 per 1,000
pounds = $4,162 per year.
http://www.energysolutionscenter.org 3/9/08
Energy Savings - Insulation
http://www.energysolutionscenter.org 3/9/08
Energy Savings - Steam Leaks
http://www.energysolutionscenter.org 3/9/08
Boiler Efficiency Analysis
www.natcomonline.com
http://www.energysolutionscenter.org 3/9/08
Source: Steve Connor, 2010
Resource
Source: Steve Connor, 2010
Compressed Air an Expensive Utility
Compressed air is the most expensive
energy source in the feed plant.
Do you know your compressed air costs?
Do you know how much compressed air is
really required for your plant?
Do you select compressed air equipment with
energy costs in mind?
Do you monitor the use of compressed air like
your other utilities?
http://www.maintenanceresources.com/referencelibrary/aircompressors/kaeserpage7.htm
Air Compressor Energy Savings
 Equipment selection
 Intake air temperature
 Operating pressure
A 2% psi reduction can save 1.5% cost
 Air leaks
 Maintenance
Oil
Filters
Belts
 Demands – vibrators, air gates
Lighting
 Lighting audits can determine if you have the
correct type of lights and lumen in different
areas of the feed mill.
 Federal & State Grants may be available to
replace lights in commercial plants
 Energy Savings Tips
Use Compact Fluorescent Lights (34watt)
Turn off lights when not used.
Use timers and occupancy sensors
Electrical Motors
Evaluate the motor load associated with each process
and determine if the motors are operating in the
recommended range.
Electrical Motors Energy Savings
 Rewinding vs. Replacement
Select a new energy-efficient motor under
any of the following conditions:
The motor is less than 40 hp.
An energy-efficient motor is recommended
according to Table 3.
The cost of the rewind exceeds 65% of the
price of a new motor.
The motor was rewound before 1980.
Electrical Motors Energy Savings
Turn off motors when not in use.
 Note: Motors have a cool downtime therefore take the
time into consideration as part of the decision.
Determine the clean out time of each conveyor in
the shutdown sequence, the conveyor only needs
to run long enough to clean out the material.
PREVENTIVE MAINTENANCE
Feed Mill Maintenance
 A safe, clean and well maintained feed mill
does not “just happen” it takes the efforts of
management, operators and maintenance.
Management has to set the example and
standards
Operators need to alert management about
potential problems before breakdowns occur
Maintenance needs to work with operators to
keep equipment maintained and sealed to prevent
dust leaks
Housekeeping & Preventive Maintenance
 A preventive maintenance program combined
with dust control measures are key elements
in maintaining a safe, clean and orderly work
environment for employees and customers
 A clean mill will leave a good “First
Impression” on management, customers and
future employees
Preventive Maintenance Program
 Effective Preventive Maintenance Program:
Goals
 Measurable
 Time Specific
Structure





Personnel
Equipment Records and History
Schedules
Spare parts and ordering
Documentation
Management of the program
 Reports and Tracking
Maintenance Goals & Objectives
 Limit Unscheduled Downtime
 No Customer Waiting Time
 Low Cost
 Well Maintained Facility
 Compliance with Safety Regulations
 No Dramatic Events
Structure - Personnel
 Hire or Contract Qualified/Trained Personnel for
Skilled Tasks
 Licensed Electricians
 Certified Welders
 Boiler Operators
 Hire experienced millwrights for repairs and
preventive maintenance task
 Pellet mill rebuilds, replacing gearboxes
 Hire employees with mechanical aptitude for general
maintenance
 Greasing bearings, cleaning magnets
Training
 Safety Training
 Lock-out/Tag-out
 Hot Works
 Confined Space
 Electrical Safety
 PPE







Eye protection
Fall protection
Cotton Clothes
Steel Toe Boots
Gloves
Hearing protection
Hard Hats
Maintenance Personnel Responsibilities
 Schedule routine maintenance
 Develop and implement a preventive
maintenance program
 Record maintenance completed on each
piece of equipment
Labor hours
Parts cost
Root cause of repairs
 Select the correct lubricants for each
application
Maintenance Personnel Responsibilities
 Seal all equipment upon completion of a task
or work order
 Clean up the area and remove old parts
 Check that material is not left in the
equipment (tools, parts, etc) that could
damage equipment or adulterate the feed.
Structure - Equipment Information
 Supplier
 National, Local
 Model
 Size, Capacity
 Mill Location
 Receiving, Grinding
 Owner Manual
 Operations, Spare Parts
 Maintenance Frequency
 Spare Parts
 Motor, Bearing, Belts
Structure - Schedules
 Time - Maintenance Schedules
 Daily
 Weekly
 Monthly
 Quarterly
 Annually
 Production Maintenance Schedules
 Ingredients received
 Feed manufactured
Maintenance Schedule - Daily
 Boiler Water Treatment
 Clean Magnets
 Grease Pellet Rolls
 Several times a shift to keep rolls purged
 Fat Traps
Maintenance Schedule - Weekly
Damaged
Screen
New
 Hammermill Screens
 Hammermill Hammers
 Housekeeping Area
Worn
Corner
Maintenance Schedule - Monthly
 In-House Scale Check
 Pellet Cyclones
Maintenance Schedule - Quarterly
 Certified Scale Check
 Air Compressors
 Conditioner Chamber
 Distributors
Maintenance Schedule - Annually
 Boiler Inspection
MCC – Infrared
Spare Parts Inventory – Critical - Stock
 Required to operate the
feed mill
 Has a long lead time for
manufacturing or shipping
 Overseas part
 Limited Manufacturing
Schedule
 Examples




Pellet Mill Motor
Gearboxes
Dies & Rollers
Computer Parts
Spare Parts – Critical – Non-Stock
 Parts that can be
purchased locally or
shipped overnight
 Parts that are
expensive and not used
frequently
 Parts shared between
other plants
 Examples
 MCC part
 Small gearboxes
 PLC cards, Modules, etc
Spare Parts – Basic - Stock
 Parts used on a regular
basis in the feed mill
 Nuts & Bolts
 V-belts
 Bearings
 Seals
 Hammermill Screen
 Hammermill Hammers
Work Order
PM History
Monthly Inspection
Feed Mill Inspection
Date
Inspected by:
Area: Receiving
OK
Corrective Action Required
Lights
Electrical
Sanitation
Fire Extinguisher
Evacuation Plan
Emergency Lights
Safety Signs
Add SPCC, Environmental Assessments, etc.
Date Completed
Cost of not doing PM’s - Example
 Problem: Not removing tramp metal from die.
Lose 10% production on a 20 ton/hr pellet mill
Lose 240 ton/wk on (24/5 operation)
 Result:
Cost $100/hr in normal labor to operate the mill
Requires 13 extra hrs of overtime/wk($150/hr OT)
$150/hr X 13 hrs = $1950 or $.81/ton on every ton
manufacture during the week.