Norton Incinerator Specifications
by John W. Norton, P.E., B.C.E.E.

Norton Engineering has developed over the years a complete design for a large municipal incineration system with energy recovery. Mr. Norton personally designed and built two such systems, one with energy recovery and one without, and operated both of these systems for more than four years.

If any civic body or government entity contracts with Norton Engineering to build one, or more, of these systems, Mr. Norton and his staff of experienced engineers will design, draw, and specify all of the necessary incinerator components for the Municipal Incineration Plant housing one or more 250 Ton per Day (TPD) Municipal Incinerators, to include:

- equipment foundations, as necessary

- all trash storing and receiving areas

- all trash handling systems

- all trash combustion systems

- all energy recovery systems

- all interconnecting duct work

- all air pollution control systems

- building layout plans

- all control systems

- all electrical distribution systems

- all motors and transmissions

- all ash extraction equipment

- all ash handling systems

- all ash reuse manufacturing systems

Designs, calculations, drawings and specifications shall be prepared by Norton Engineering's experienced staff using computer based office and engineering systems. This engineering service on this Project shall be performed exclusively for the contracting agency. Some of this engineering service may be subcontracted by Norton Engineering where it seems likely that subcontracting will save project expense. Drawings will be reproduced on AutoCAD computer based drafting systems.

If the contracting agency is interested, Norton engineering can assist the agency to have much of the work and components manufactured in the vicinity of the contracting agency, Korean Companies for example.

The Basic Services of this proposed Work includes:

- fabrication drawings

- equipment designs & layout drawings

- 4 design meetings, as and if necessary, away from the Engineer's home city office by Mr. Norton and/or his designated agent(s), and reports of same.

- bid drawings

- specifications for manufacture and supply

- fabrication bid evaluations and reviews

- construction drawings

- assembly and erection drawings

- 5 site inspections of 12 day duration by Mr. Norton or his designated agent(s) and reports of same.

The proposed plant shall be designed to be similar to the ones designed, built, and operated by Mr. Norton for Montgomery County in Dayton, Ohio. This engineering service will be performed so that officials and the public may inspect its superior ability to destroy wastes while producing energy and useful construction materials.

The Project to be built for demonstration purposes will be capable of burning in clean combustion 250 long tons of mixed municipal solid waste with limited water content per incinerator line. This demonstration plant will produce ash of only approximately 10% volume of the incoming waste. This ash will be processed to recover steel and produce usable construction materials such as roadway base (substitute for sand and crushed rock) and construction blocks. Ash product can be used for road construction base if washed and cured with cement.

Heat released from this combustion shall be used to make steam to generate electricity. Some steam may be used for industry at their connection expense.

Construction of buildings and installation of equipment can be by contracting agency, Korean Companies for example. Also some equipment manufacturing can be done in Korean factories and machine shops.

When the first plant is demonstrated to be successful, others can be built from the same and improved plans. Perhaps more machinery can be manufactured in Korea (or another contracting vicinity) for subsequent plants after the first one is demonstrated to be excellent.

ESTIMATED FACILITY SIZE & SPECIFICATIONS

Contracting entities shall supply a site appropriate for construction of the proposed facility. The very best land size for a solid waste incineration facility is approximately 40,000 square meters on a hill side, although a plant can be designed for a smaller site. The incinerator plant footprint is to be approximately 10,000 square meters. Ash processing and energy production will require more space. A hill side is good because the building can be adapted to a slope which accommodates 5 standard floors of elevation in approximately 100 horizontal meters. The incinerator has an entrance about 15 M above the ash truck loading floor. Thus, the facility may be made to conform to a slope.

The exhaust gas stack (chimney) should extend above the general terrain in the immediate vicinity of the plant, in order that the combustion gas products be adequately dispersed. Adjacent hills shall not be so tall as to hinder stack gas dispersion from a 35 meter tall stack.

The appearance of the plant (to be constructed by others) should be in keeping with the architecture of similarly sized manufacturing facilities. Trash truck deliveries will be kept indoors to minimize odor and disorderly appearances. Ash handling and processing will be kept under roof and indoors so that it is not offensive to the neighbors and also so that operations may be conducted year round in all types of weather.

There will be a cooling tower ( perhaps 3 meters high and 15 meters square) that will emit a white cloud of clean water vapor during many seasons of the year -- especially during the winter.

Bunker areas for the storage of completely processed ash, ready for use as sand substitute will be designed into the Project.

ESTIMATED ENERGY PRODUCTION

After completion, the facility will produce an approximate average of 3 to 4 megawatts of electricity per 250 TPD incinerator line, more if solid waste is high in energy content. The machinery will only require approximately 0.7 megawatts per 250 TPD line for operation. Thus, this facility is likely to produce a net benefit of 2.5 megawatts of electricity while it destroys 250 TPD of mixed municipal solid waste and produces steel and sand substitute for sale.

The proposed plant will be patterned after the two municipal incinerator plants in Dayton, Ohio, which historically received approximately 500,000 tons of waste each year and managed to burn nearly 80% of that material. The energy recovery system on the prototype line in Dayton operated successfully for seven years, producing about 5 megawatts of electricity during its 90% on line time until all incineration ceased in Ohio. Ash from the incinerators was used successfully for road base for many miles of asphalt bicycle paths along Dayton's rivers and it has also been used in concrete blocks which have been used to construct two large buildings.

PROCESSING PLAN

The incineration chamber will be designed to include an auxiliary gas or oil burner to be used as necessary to maintain the proscribed minimum combustion temperatures. Experience, however, indicates that use of the burner will not be necessary to maintain temperatures of 700^oC, or higher. In practice some dry solid waste which makes good fuel should be held back for times of trouble. This is typically cardboard or wooden scraps.

The residence time for gaseous products in the hot combustion chamber will be designed to be at least 1 second to insure a good burnout. Temperature recording devices will keep a continuous record of the temperatures in areas of interest such as the primary combustor, the air pollution control equipment, and the exhaust stack.

Overfire air will be introduced in a fashion to provide good mixing of the combustion products. Video cameras will be installed for viewing from the main control room so that human interpretation of the combustion conditions can be made continuously. There is no substitute for a good human eye when trying to make an efficient fire.

Temperatures of critical points, flows of gases and water will be monitored by an on line computer capable of warning the operator of unusual conditions and in some cases of making the necessary changes. One good example of such computer controlled ability is the control of the vacuum strength by computer adjustment of the fan dampers.

The combustion chamber will be constructed of stout steel members and a steel shell (minimum thickness 4 mm). The steel shell will be protected from the fire with a combination of refractory brick and poured and plastic refractory of good quality meeting or surpassing Korean Industrial Standards. Access doors for maintenance will have little windows for careful viewing of the fire. The outside surfaces of the combustion chambers will be kept to no more that 80^oC by the use of adequate refractory and insulation materials.

The steel shell will be fully welded to provide an air tight enclosure for the combustion. This will prevent the careless inflow of air to the fire and the escape of any combustion products in an uncontrolled fashion. The appearance of the outside of the incinerator will be maintained in first class condition by the use of fireproof paint, or other protective materials of good appearance.

It is also possible to automate stack monitoring for opacity, temperature, and flow and CO₂ content. For additional cost, it would be possible to install automatic systems for such recording.

DESCRIPTION OF THE COMPONENTS

In the course of the specific design of this project, changes in the design of these following components may be made in order to accommodate regional requirements and practices, and manufacturing capabilities:

SCALES: The new Norton Engineering Incinerator will have entrance scales for all incoming waste to provide an electronic readout so that a daily record will be generated showing such information as source of trash, amount, driver's name, etc. This will allow computer analysis of the entire waste receiving (and accounting) function.

TIPPING FLOOR AND ENCLOSURE: The tipping floor will be completely enclosed and combustion air for the incinerator withdrawn from this area to insure that clean air is constantly drawn into this front end area. This insures that odors and dust are captured and incinerated, thus destroying both.

The tipping floor area will include machinery for gross separation of incoming solid waste so that moisture can be minimized. Many vegetable/organic items will be conveyed away from the combustible solid waste storage area so that they can be composted, and not burned.

FIRE PROTECTION: The Norton Engineering Incinerator will have a manually controlled solid waste storage spraying system similar to an automatic fire sprinkling system. This can be activated quickly in the case of solid waste storage fire, and as needed to control dust during dry seasons.

Television monitors will be installed in the storage area so that the combustion control board operator can keep track of the movements of the crane operator and help to keep "fire watch."

INCINERATOR ENTRANCE AREA FEED HOPPER: The entrance feed hopper will consist of a heavily reinforced concrete funnel. The concrete used will be high strength, 35 MPa.

HOPPER LIDS: The entrance hopper closing lids will have a pivoted lid normally held in a position which allows gravity to close it. This system will have a manual clutch which an operator can disengage--if power fails for any reason and the lid must be closed. It is critically important on occasion to get the hoppers closed off quickly. If power has failed, for example and the trash burns down in the feed chute, then (in the absence of forced draft) the fire can come back up the chute and damage the roof or ignite the stored solid waste.

FEED CHUTE: The feed chute will be refractory lined. While this refractory does wear, it is very slow and predictable. It will be constructed of simple straight refractory bricks. The feed chute "arch" at the bottom of the feed chute will be a poured refractory arch.

IGNITION AREA CEILING: The ignition chamber ceiling will be established at a height that will allow for a large area for heat energy release. The arch in this area will reflect heat back onto the trash and deflect hot gases back onto the drying grate area for drying the trash in times of high moisture.

DRYING GRATES: The drying grates will be constructed of 309 stainless steel. These may be cast alloy or may be welded at local machine shops depending on pricing and availability. Their uniform design will allow a reduction in inventory of spare parts.

AIR COOLED BEAMS: Between section of grates, air cooled beams face the fire. They are fabricated of 309 Stainless Steel.

IGNITION GRATES: The Ignition Grates are to be fabricated of 309 Stainless Steel. These grates are attached to fabricated steel support beams (or "Stringers"). These stringers are to alternate--one movable between two fixed. There are to be thirteen across the ignition and drying areas--six movable and seven fixed.

These grates should be easy to install and replace, and can be repaired in the unit with welded patches, as can the drying grates above. Several local fabricating shops should be able to bid on the work with resulting competition and economy.

These grates will have underfire air slots although much of the underfire air will pass between the separate grate stringers. It is believed that this is a good point of passage for the majority of the air because this is the one area constantly kept open by the reciprocating action of the grates.

FLAPPER SEALS: The upper end of each grate section will be protected from solid waste by flapper seals made of 309 Stainless Steel attached to the fixed (stationary) grates.

GRATE DRIVES: The grates are to be driven by push rods fabricated from a single piece of rectangular steel for added strength and ease of fabrication--bushing sleeves will be added to each pin connection. Hydraulic drives could be used on the grates if this is desirable to the owner. It is thought that this might provide a substantial relief from pin and linkage maintenance, but it would carry with it an unknown amount of hydraulic system maintenance.

REFRACTORY ROOF: The refractory roof will be constructed of "Super Duty" hanging brick--equal to either Detrick, or Chicago Fire Brick. This system is supported by 8 CM "I" beams on 40 CM centers.

REFRACTORY SIDEWALLS--UPPER: The upper sidewalls of this unit are to be 0.5 M thick. These thick walls provide a huge reservoir of heat energy to buffer the temperature resulting from varying fuel characteristics. These heavy walls help resist and buffer explosions which can occur in the furnace from various mixed waste.

REFRACTORY SIDEWALLS--LOWER: The lower sidewalls of the Norton Engineering Incinerator are to be Silicon Carbide refractory. This system uses tongue and groove silicon carbide brick shapes with metal tie backs to provide a rugged cooled surface near the grates where the burning trash rubs the sidewalls. Air is forced behind the silicon carbide bricks for cooling, and this heated air is used for underfire and overfire air. (After it has been used to cool the sidewall in this area it is about 110 ^oC.)

This lower sidewall cross section will consist of 10 or 12 CM of silicon carbide refractory, a 12 to 15 CM airspace (for cooling), and a conventional straight brick backup wall which in total gives a wall 50 to 65 CM thick.

UNDERGRATE HOPPERS: The drying grate hopper is to consist of a smooth, steep funnel and chute to pass the grate siftings down to the ignition grate hoppers with minimum dust or emissions.

IGNITION GRATE HOPPERS: The ignition grate hopper will also consist of a smooth, steep funnel that passes the grate siftings down into a flooded drag conveyor which is intended to pass siftings from the ignition grates and kiln seal up and into the ash drag conveyor without dust or smoking. This will allow the maintenance of a positive air pressure under the ignition grates while keeping grate siftings in air tight conveyors while it is passing out through the system. (Close personal inspection of many competitor plants indicates that the positive underfire air situation is actually seldom attained in practice--except for short periods of time under ideal test conditions.)

ROTARY KILN: The rotary kiln will be designed with variable speed control to function as the final burn out grate. Slow turning speed of about 4 revolutions per hour will allow the waste to dry and break down before it is dropped into the ash removal conveyor.

The rotary Kiln design has excellent characteristics for solid waste that is heavy and containing more moisture. A reasonably tight air seal is to be provided to control the amount of air allowed to enter the combustion process at either end of the kiln.

KILN REFRACTORY: The Norton Engineering Incinerator uses a 30 CM super duty wedge type brick system with no special insulator bricks. This brick lining should give an average skin temperature of 200 ^oC, and a useful life of about 18 months for the quickest wearing area, the 4 M near the discharge end. The 4 M on the inlet end should last up to 3.5 years. Operating conditions such as temperature can increase or decrease the life expectancy of the kiln refractory.

KILN OVERPASS: The kiln overpass shall consist of a steel duct lined with super duty refractory. Its ceiling is to be made of super duty brick shapes supported by 6 CM "I" beams on 40 CM centers. The object of the kiln overpass is to provide a passage for the easily volatilized gases from the primary combustion zone, allowing them to quickly burn out without causing rapid gas velocity in the rotary kiln.

RESIDUE (ASH) CONVEYORS: This is the most troublesome area in plant operations. The Norton Engineering ash removal system is to be designed with high strength to resist the wear and binding inclinations of the metal laden ash material. It will be a heavy drag conveyor submerged in water at the ash removal area to maintain the positive seal on the combustion area and quench the burned out, red hot ashes. The conveyor chain will be approximately 22 CM pitch high alloy cast steel with ultimate strength of 160,000 KG.

The design will locate the ash conveyor where it cannot flood, above ground. Design should provide easy access to the ash conveyors for heavy equipment for maintenance. There will be easily employed backup systems. The conveyor flights will be closely spaced to prevent material from wedging between the flights and the conveyor trough walls. The conveyor will have a drive assembly at each end to allow for power reversing. The drive will be hydraulic to eliminate the shear pins and provide heavy force at slow speed.

The design will have the shortest drag conveyor possible to dump the ashes into a large ash storage pit. Wheel loaders will be used to load the ashes onto highway dump trucks for the trip to the ash processing site, if remote.

CONDITIONING CHAMBER, OPTIONAL: Even though a boiler is to be installed and used as the primary gas cooling device prior to the air pollution equipment, it is recommended that a conditioning chamber be installed in parallel with the boiler to provide for continued operation when the boiler is down for maintenance, or steam is not required.

A conditioning chamber is a tool with which to gain a substantial operating advantage. It consists of a refractory lined steel chamber, temperature controlled water sprays to lower the gas temperature, and an exit thermal couple to read the exhaust temperature. The new conditioning chamber would include a submerged drag conveyor and water air seal through which to remove fly ash. Excess cooling water that falls on the floor of this chamber would overflow though the air seal dam and be cleaned up and recycled for use in the temperature control system to avoid sewer charges.

A control damper located in the exhaust duct from the conditioning chamber would allow the flue gases to be directed to the boiler. This damper could be used to control the amount of heat going to the boiler in the same fashion that fuel control is used for this purpose in a fossil fueled boiler.

BOILER: The boiler shall be designed with smooth tubes and wide gas passages to minimize the wear during operations. The boiler will use relatively low pressures and temperatures so that high temperature corrosion is minimized. The boiler, if by ABB/Alston Power Company, may be constructed in Korea.

TURBINE GENERATOR: The turbine generator will be highly efficient for making electricity and designed to accept the relatively low temperature and low pressure steam developed by the boiler. The turbine if by Coppus Murray, will include an OPTIONAL steam extraction port for later use in the supply of steam energy to manufacturing facilities if that becomes more economically reasonable than continued maximum electric production. Steam from the exhaust side of the turbine will be condensed for reuse in the boiler.

AIR POLLUTION CONTROL: The Norton Engineering Incinerator will employ highly efficient bag houses or dry electrostatic precipitators for particulate removal. The preferred method of particulate control is the electrostatic precipitator (EP) for the following reasons:

-The EP has less pressure drop across it than a baghouse. This results in much less energy consumption during operations.

-The EP will not "blind" as a bag house will from the great percentage of sub micron particulate that an incinerator generates.

-The EP is less susceptible to "crusting" from sticky fly ash, and if these substances do coat the EP collection surfaces they can usually be "burned" off by temporarily elevating the EP temperature to approximately 375 ^oC.

-The EP is less susceptible to damage from temperature excursions than a bag house. Incinerator temperatures sometimes vary with surprising speed--for example during a water failure in the conditioning chamber.

-The EP is less susceptible to damage from smoldering embers which are occasionally carried back to the control device.

The electrostatic precipitator is the collection device of choice when the whole picture is considered: down time, operating costs, capital costs, life expectancy, replacement parts costs, and risks associated with catastrophic failure (such as bag house fires.)

The proposed plant can meet any specified emission limits. It is wise to demand the same air emission limits as a modern coal or oil fired power plant.

ASH PROCESSING: The ash processing system will include machinery for separating and stabilizing the ash product with lime and cement so that it can safely be used in construction for fill material or as construction blocks. Synthetic aggregate product may be safely stock piled for use in large projects. Steel and other metals will be recovered for sale to steel mills and other raw metal processors. Very little, if any, material will be left over and require landfilling after the ash has been processed.