Technical Information
Custom Engineering
Operation Safety
Reliability & Long Life
Economy of Operation
Operating Principals
Automatic Loader
Primary Chamber
Secondary Chamber
Ash Removal
Intrumentation & Control
Technical Information about Pennram
Incinerators, Crematory Systems and Incinerator Systems
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 0.013 gr/dscf (29mg/Nm2) corrected to 7% oxygen before going into the air pollution system. The average opacity is less than 1%, which is not visible.
• Achieved up to 99.95% 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.
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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.
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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.
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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.
Operators time requirements are 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.
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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 15,000 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 be 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.
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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.
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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 (135-340 kg/hr) unitsThe extra hearth(s) means that waste will "roll and agitate" several more times as it moves through the chamber, ensuring even gasification.
- 2 level hearth, 1 ram.
800-2,800 lb./hr (360-1270 kg/hr) units
- 3 level hearth, 2 rams.
3,000-5,500 lb./hr (1360-2500 kg/hr) units
- 4 level hearth, 3 or 4 rams.
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 others 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.
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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.
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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.
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Instrumentation and Control
Pennram offers programmable control (IBM compatible) systems for the incinerator. Typical instrumentation and controls furnished with the incinerator are as follows:
1. 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.2. 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 also 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.
1. 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.2. 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.3. 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.4. 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.5. 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).6. Emergency Dump Stack Cap Interlocks
• System on.
• Air pollution system interlocks closed.
• Proven primary chamber negative pressure.7. Ash Conveyor Interlocks.
• Ash conveyor switch in auto position.
• Ash ram stroke interlock.
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