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Custom-design
Engineering
Every incinerator and crematory supplied by Pennram
is designed and manufactured according to its specific
application and is in full compliance with government
environmental and safety regulations. This tailor-made
engineering approach is to ensure the incinerator
meets the exact needs of each customer.
Pennram incinerators and crematory systems have demonstrated
high system performance with:
Accurate control of secondary chamber temperature
to assure complete destruction of organic and other
harmful substances in the off-gas.
Achieved particulate concentration in incinerator
off-gas as low as 0.039 gr/dscf (100mg/Nm2) corrected
to 7% oxygen before going into the air pollution
system. The average opacity is 1%, which is not visible.
Achieved up to 995 reduction of waste by weight.
The high performance of the Pennram incinerators
and crematory systems is achieved by good engineering
design of each equipment component, quality construction,
practical control logic and full monitoring instrumentation
provided as an integral part of the unit. The air-tight
construction of the incinerator chambers and the automatic
loader minimizes in-leakage, eliminating the major
cause of low incinerator performance.
Operation Safety
Pennram incinerators and crematory systems are provided
with complete safety interlocks, including electronic
flame supervision, start-up and shutdown system purge,
loader operation, safety interlocks and alarms, primary
and secondary chamber high/low temperature alarms,
system fan operation interlocks, and emergency dump
of off-gas to assure operator's safety as well as
to avoid damage to the incinerator and the air pollution
control system under normal operating conditions.
Reliability
and Long Service Life
The material selection as well as the mechanical
design and construction of the Pennram incinerators
are aimed at the goal of reliable operation and long
service life. The life expectancy of Pennram incinerators
is 15 years or more.
Economy of
Operation
The auxiliary fuel requirement of the secondary chamber
to maintain the high incineration temperature, i.e.
the main factor fuel consumption of the incinerator,
is less with Pennram incinerators compared with other
makes. The good fuel economy of Pennram incinerators
is achieved by the efficient primary chamber design
and the effective primary combustion air control
of the Pennram incinerator, which facilitate maximized
vaporization of hydrocarbons contained in the waste.
Operator's time requirements is also less for Pennram
incinerators because of the high level of automation
incorporated in the design, such as the automatic
hydraulic loader, automatic ash removal, as well
as the clear visual display of operating parameters
on the control panel, which makes the operation of
the incinerator relatively easy.
Incinerator
Design and Operating Principles
The Pennram incinerators are offered with an automatic
hydraulic loader, automatic ash removal system, and
complete instrumentation for 24-hour continuous operation.
They are of the controlled air type. The destruction
of waste takes place in two stages. The waste is
fed into the primary chamber by the automatic hydraulic
loader. The primary chamber maintains a substoichiometric
or starved-air atmosphere at approximately 1,5000
degrees F (816 degrees C), under which condition
volatile hydrocarbon gases are driven from the waste.
Fixed carbons are burned in the primary chamber and
remain in the form of ash.
The hydrocarbon gases flow from the primary chamber
through the flameport and into the secondary chamber.
The secondary chamber operates at a temperature of
1,400 to 2,000 degrees F (760 to 1,093 degree C)
depending on the regulatory requirements. In the
secondary chamber the hydrocarbon gases are heated
and oxidized under very turbulent conditions. The
air flow to the secondary chamber is carefully controlled
to maintain low oxygen content and to control exhaust
temperature.
Of utmost importance is the Pennram method of control
of secondary combustion air. The goal is not only
clean emission and control of temperature, but also
optimal fuel economy for the system. The air flow
to the secondary chamber is reduced when a supply
of oxygen is not needed. In this way the chamber
will not be dilution cooled to the point where additional
fuel will be required to maintain minimum exhaust
temperatures.
The waste heat from incineration systems are typically
directed to a heat recovery boiler, hot water heater,
or air to air heat exchanger. Heat recovery not only
provides enhanced system payback, but also reduces
the cost of air pollution control equipment. If there
is no need for steam of hot water, the customer may
elect to utilize the waste heat to generate electricity.
Pennram offers skid-mounted turbine generator packages
which are both economic and reliable. Installation
only requires that the utilities by connected to
the skid.
Depending on customer requirements, the fuel used
for the incinerator may be natural gas, diesel oil,
or No. 6 fuel oil, or other fuels as directed by
the customer. The system electrical supply (voltage & frequency)
is dictated by the customer.
The design features of the above-mentioned incineration
equipment are described further in the following
sections.
Automatic Hydraulic
Loader
Current environmental regulations require that, while
charging, the incinerator must maintain controlled
air condition and there must be no fugitive emissions
from the unit. Pennram automatic hydraulic loaders,
designed for fully automatic operation with necessary
interlocks, not only meet these requirements, but
also greatly improve operator safety and reduce the
operating labor needed for the charging operation.
Pennram automatic loaders are of a heavy steel construction.
The entire ram assembly is made of A36 '" (6.4mm)
carbon steel plates, shapes and tubes. The internal
plates and tubes are all tied into each other and
the exterior surfaces of the charge ram to complete
a very rigid structural component able to withstand
the mechanical and thermal stresses of tens of thousands
strokes in and out of the incinerator. The charge
ram is connected to the hydraulic ram shaft at the
center point of its face. The charge ram is driven
by two opposing hydraulic cylinders "piggy-backed" together.
A refractory insulated firedoor is provided to isolate
the waste from the primary chamber. The firedoor
is designed to allow waste to lay directly against
the door without melting, smoldering, or catching
fire. This configuration allows the cold side of
the door to stay below 130 degree F (55 degree C),
while the primary chamber is continuously operated
at 1,500 degree F (816 degree C).
One of the most important features of Pennram loaders
and primary chambers is that they do not leak air.
Air leakage into the primary chamber, which is operated
under a slight negative pressure, is the number one
problem with many incinerators, as excess air in
the primary chamber makes it difficult to control
the temperature.
The "charge" operation is initiated by the operator
pushing the "Charge" push-button. The ram feeder
is then set in motion by the closing of all charge
interlocks, which include time, temperature, proper
exhaust conditions )oxygen concentration, or opacity),
and safety interlocks. Once all the charge interlocks
are satisfied, the following sequence takes place:
Firedoor fully opens. Charge fully extends (waste
is pushed by into the primary chamber). Charge ram
retracts to a position clear of the firedoor and
stops. Firedoor fully closes. Charge ram fully retracts.
Hopper lid opens.
All components prove position before continuing
the sequence. An adjustable water spray is initiated
when the firedoor closes. If the system has ash rams,
the rams cycle prior to the charge sequence. If there
is more than one ash ram, the lowest ram cycles first.
Primary Chamber
Pennram's primary chamber is superior to that of
other makes mainly in the hearth design and the
way the combustion air is introduced. In the vertical
model, air is introduced into the center of the
chamber as well as the sides of the chamber. The
primary chamber is of an air tight design, eliminating
in leakage of unwanted air.
In the horizontal models, Pennram uses the multiple
hearth design. For example:
300-750 lb./hr (136-182 kg/hr) units
- 2 level hearth, 1 ram.
1,000-1,500 lb./hr (227-6282 kg/hr) units
- 3 level hearth, 2 rams.
2,000-6,000 lb./hr (227-682 kg/hr) units
- 4 level hearth, 3 or 4 rams.
The extra hearth(s) means that waste will "tremble" several
more times as it moves through the chamber, ensuring
even burning.
Combustion air is introduced in the horizontal models
under the fire for even burning and reduced ash.
The under fire air is introduced via carbon steel
tubes that are embedded in the hearth. The major
advantage of this method is that all the air introduced
is forced to contact the burning pile, in effect
achieving maximum vaporization of hydrocarbons from
the waste in a substoichiometric atmosphere.
Pennram uses a much heavier liner in the chamber
than other and in many cases a heavier shell. Pennram
uses a full 9" firebrick liner consisting of 4-1/2" firebrick
and 4-1/2" insulating firebrick; the poured sections
of the chamber consist of 6" castible refractory
and 3" of block insulation behind the refractory.
The heavier firebrick costs more, but lasts longer
and is more resistant to the chemical attack of the
internal atmosphere, thus ensuring long-term efficiency
and economy.
In the design of Pennram incinerators, air delivery
to the primary chamber is cut off during a charge
to avoid the initial flash of volatile waste into
hydrocarbon. This "flash" is uncontrollable in the
presence of excess oxygen at high temperature and
often results in visible emissions. The air is controlled
to prevent these upset conditions.
Secondary Chamber
Pennram uses a unique configuration of combustion
air manifolds and jets. With this arrangement air
and waste fuel are introduced in a manner that
encourages turbulence and mixing.
Air introduction to the secondary chamber is fully
modulated by variable speed controls of the fan motor
or by modulation of an air control damper. The control
of air delivery to the secondary chamber is cycled
with each firedoor opening to the primary chamber
and is controlled by the secondary chamber temperature
and / or exhaust levels.
Similar to the primary chamber, the Pennram secondary
chamber is also provided with heavier refractory
and insulation liner than others for better performance
and longer service life.
Ash Removal
In the vertical models the ash is manually shoveled
from the incinerator. An ash door is provided for
easy access. The ash door is equipped with a proving
switch that will not allow the primary chamber
components (burner, combustion air blower) to operate
while the door is open.
In the horizontal models the primary chamber is
equipped with one or more ash rams, depending on
the number of hearths provided for the incinerator.
With the multiple level fixed hearth unit, the lowest
ram is the ash ram. The next level is the stoker
ram in a two-ram system. The ash rams stroke prior
to each charge starting with the lowest level ram.
The idea is that each ash ram stroke clears a void
in its ash way. The void in the upper most ash way
is filled by the charge ram pushing material off
the main hearth. The multiple hearth provides periodic "turning" of
the waste as the burning waste/ash tumbles onto the
next hearth. Eventually, after the waste is charged
onto the main hearth, tumbles, and stroked by the
rams, it drops off the last ash way into the ash
chute. The ash chute is partially submerged in a
wet ash conveyor trough. As the ash is dumped into
the chute, it dowsed in water and transferred by
the automatic ash removal system directly to the
ash container. The automatic ash removal system may
be a screw conveyor, a drag conveyor, or other transfer
system depending on application. The water in the
ash trough provides an air-tight seal to the ash
chute.
The ash ram and ash conveyor may be operated manually
with forward and reverse switches or fully automatic.
The ash rams are fully enclosed within the envelope
of the primary chamber. All of the ash ram hydraulic
components and proving switches are on the outside
of the enclosure, where they are protected from heat
and dirt.
Instrumentation
and Control
Pennram offers programmable control (IBM compatible)
systems for the incinerator. Typical instrumentation
and controls furnished with the incinerator are as
follows:
- Incinerator control System
• Loader operation.
• Modulating system fan air dampers.
• Modulating of secondary burner.
• Primary burners.
• Fire-eye flame controls.
• Temperature controls and lockouts.
• Primary combustion air blower.
• Secondary Combustion air blower.
• Safety and operating interlocks.
• Recorder.
- Monitoring Equipment
• Primary exit temperature monitor.
• Oxygen monitor.
The above-listed instruments are housed in a free
standing NEMA 12 control panel complete with power
distribution breakers, motor starters, inverter
drivers, display modules, cycle counter, control
transformers, annunciator, and digital charge timer.
Pennram offers also relay logic control systems
with control features tailored to the customer's
requirements.
The minimum control interlocks furnished with typical
Pennram incinerators are listed below.
- Automatic charging interlocks
• Charge timer.
• Shutdown mode timer.
• Primary temperature limit (high only).
• Secondary temperature limits (high and low).
• Charge hopper proven closed (hopper is closed after filling by pressure
hopper close button).
• Hydraulic system manual-auto switch in auto position.
• Air pollution control system interlocks closed.
• Stack cap closed.
- Primary burner interlocks
• System on.
• Shutdown mode time.
• Primary temperature burner operating limit.
• >Primary chamber access door proven closed.
• Charge firedoor proven closed.
• Primary burner off-on-auto switch in on or auto position.
• Air pollution control system interlocks closed.
• Stack cap closed.
• Remote burner switch in on position.
• Post load delay timer.
• Proven primary chamber negative pressure.
• Start up pre-purge interlock.
- Secondary burner interlocks
• System on.
• Shutdown mode timer.
• Secondary temperature burner operating limit.
• Secondary burner off-on-auto switch in on or auto position.
• Air pollution control system interlocks closed.
• Remote burner switch in on position.
• Start up pre-purge interlock.
- Primary combustion air blower interlocks
• System on.
• Shutdown mode timer.
• Primary chamber temperature operating limit (high only).
• Primary chamber access door proven closed.
• Charge Firedoor proven closed.
• Air pollution control system interlocks closed.
• Stack cap delay timer.
• Post load delay timer.
• Start up pre-purge interlock.
- Secondary combustion air blower interlocks
• System on.
• Shutdown mode timer.
• Air pollution control system interlocks closed.
• Start up pre-purge interlock.
• Secondary chamber operating limit (high only).
- Emergency dump stack cap interlocks
• System on.
• Air pollution system interlocks closed.
• Proven primary chamber negative pressure.
- Ash conveyor interlocks.
• Ash conveyor switch in auto position.
• Ash ram stroke interlock.
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