Transcript New Energy Efficient Boilers and Systems

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Tank Heating by Various
Methods for Metal Finishing
and Other Process Heating
Applications
OVERVIEW
Industries Using Process Tanks
Metal Processing & Finishings

Plating (Chrome, Brass, Precious Metals)

Anodizing

Galvanizing
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Phosphatizing

Spray Wash Systems

Pickling

Quenching
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Food Processing

Hot Oil Anodizing
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Corn Cooking (tortilla chip manufacturing)
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Food preparation in Jacketed Kettles (open tanks)
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Dairy (vat type milk pasteurizing, cheese processing, CIP systems)
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Juice pasteurizing (typically with plate & frame heat exchanger)

Breweries (craft, micro breweries)
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Food Plant Cleanup
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Egg Processing (egg washing)
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Poultry Processing (scalding tanks)
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Miscellaneous

Cosmetics Manufacturing

Aloe Vera Processing
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Common Sources For
Process Tank Heat

Direct Firing (through large diameter tube in tank)
Electric Immersion Heaters

Steam (through heat exchange coils)

Hot Water (through heat exchange coils)
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Heating Methods
Electric Immersion
Heater
Heaters
Immersed in
Tanks
Direct Gas Firing
Typically through a
welded steel fire
tube along the
inside lower portion
of tank
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Steam
Through heat
exchange coils or
panels immersed in
tanks
Hot Water Closed
Loop Recirculating
Through heat
exchange coils
or panels
immersed in
tanks
Electric Immersion Heater
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ADVANTAGES & DISAVANTAGES
ADVANTAGES

Efficient method of heating

Heaters take up small space in tank
DISADVANTAGES

High cost of electric power(in most areas)

High voltage power at tanks

Potential fire hazard

Heaters fail, need to be replaced periodically

Potentially high temperatures at heater –
could damage some baths
Direct Gas Firing
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ADVANTAGES & DISADVANTAGES
ADVANTAGES

Moderate cost for single tank installation
DISADVANTAGES

Requires separate burner system for each
tank

Can be inefficient due to limitations of tube
surface area – typically only 60% to 70%
efficient

Not suitable for use in polypropylene tanks

Potential fire hazard

Low NOx burners not available
Steam
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ADVANTAGES & DISADVANTAGES
ADVANTAGES

Highly efficient method of heat transfer - (better
that the two methods listed above) -

Heat exchange coils can be located along side(s),
end(s), or bottom of tank
DISADVANTAGES

Typically a central boiler with piping to all heated tanks –
(this could be viewed as an advantage)

Steam boiler requires soft water, boiler water treatment,
blowdown – periodic internal inspections, maintenance

Some jurisdictions require boiler operating permit,
attendant, licensing

Higher capital cost
Hot Water – Closed Loop Recirculating
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ADVANTAGES & DISAVANTAGES
ADVANTAGES

Normally this is the best choice of all listed heating methods

Highly efficient method of heat transfer – Parker offers Hot Water
Boilers with up to 86% efficiency

Heat exchange coils can be located along side(s), end(s), or
bottom of tank

Low system maintenance cost compared to steam – closed
system means no water makeup or continual water treatment or
blowdown

Typically no boiler attendant required
DISADVANTAGES

Typically a central boiler with piping to all heated tanks – (this
could be viewed as an advantage)

Tank temperature may be limited by maximum outlet
temperature of some boilers (not a problem for Parker Hot Water
Boilers, as we can run as high as 350°F without sacrificing long
service life)

Higher capital cost
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Brief Description of the
Electroplating Process

Items to be plated are immersed in a “bath” (a tank containing
chemicals to enhance the plating process, and amounts of the
material of plating). A Direct Current is applied to the target items
and the plating material, which causes the plating material to
migrate to the item to be plated.
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Some Common Terms Used in the
Metal Finishing Process:
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
Immersion Heaters – electric heat source

Immersion Coils – (may be pipe or panel coils) steam or hot water

Bath – The contents of the liquid in the tank, including the chemicals used.
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Bath Depth – The depth of the liquid in the tank

Bath Temperature – The ideal temperature of the bath to accomplish the
plating process
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Working Depth – The effective depth of the usable part of the tank

Freeboard – The empty space between the bath surface and the top of
the tank

Rectifier – A device which converts AC power to DC power for use in the
plating process
Typical Tank Configurations

Most common are rectangular, open top

Sometimes “utility” or “mother” tanks are used – these may be
remote from the process stank, and typically contain heat
exchanger, filtration system, etc.
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Figuring The Heating Load
OVERVIEW
Tank Heat Losses

Bath surface area

Tank sidewalls
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Agitation (air, mechanical)
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Fume hoods

Product throughput

Makeup water / overflow to/from tank
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Heating System Sizing & Selection
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
Length of time desirable / allowable for system heat-up from cold start.
This is critical, as it determines the size of the entire heating system. For
smaller systems, 3 to 4 hours is typical. For larger systems, 8 to 10 hours may
be more practical. These times are guidelines – final decision should be
based on an informed customers decision.

Output temperature of heating system must be high enough to provide
“thermal drive” to heat highest tank temperatures in the system.

If heat source is steam, be sure that any condensate lift requirements can
be handled by steam pressure, otherwise a condensate lift station may be
required.

If heat source is hot water, be sure velocity flow is within design
parameters and pressure drop through coils is within capability of system
pump.
Heating Coil Sizing & Selection

Must be of adequate heating surface to handle tank heating load per
calculations

Must be rated for temperature and pressure of heating system –

Coil material selection must be compatible with bath chemistry and
approved by customer for appropriate resistance to corrosion.
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We At Parker Boiler Company
Make It Easy To Figure The System
Heat Load And To Select The
Appropriate Equipment With
These 3 Steps:
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
- Get the appropriate tank data from customer per our TANK DATA WORKSHEET
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- Plug that data into our SPREADSHEET
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- Size and price the proper Parker System
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Sample Plating Job
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High Temp.
Hot Water
System
Single Boiler /
Single Pump
Diagram
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