NFDA Cremation 2 Flashcards
A type of incinerator that provides for a controlled combustion process, with the purpose of reducing human remains to carbon dioxide, water vapor, other gases, and small noncombustible residues that are further processed in an environmentally acceptable manner.
Cremators
- Oxygen
- Heat
- Fuel - most commonly fossil fuel, it reacts with oxygen to produce heat.
3 Things (In right Proportions) Needed for Combustion
The resulting chemical reaction of oxygen, heat, and fuel: it cannot start or continue if one of the three elements is not present or is removed. Occurs when a combustible material, in combination with a sufficient quantity of oxygen, is exposed to an external ignition source (heat or ambient temperature) above te flash point for the fuel and oxidizer mix.
- Heat- a form of energy
- Oxygen- most common oxidizer
- Fuel- most commonly hydrocarbon based
Fire
A chemical process where molecules rearrange themselves, either releasing or absorbing energy.
Oxidation
Must be able to sustain a rate of rapid oxidation that produces a self-sustaining, exothermic chemical chain reaction.
- Resulting reaction continues without the need for an additional external ignition source, and continues until all the available fuel is consumed, removed or the temperature reduced by cooling.
Chemical Reaction
A process that releases energy in the form of heat
Exothermic
A rapid oxidation process, in which hydrocarbons react with oxygen, releasing a great deal of heat and light in the process.
Incinceration
Results when the heat does not dissipate faster than it is created. In an incinerator, the objectives of this are the complete destruction of the organic constituents to form harmless gases and preventing the release of any harmful materials into the atmosphere.
- Complete
- Stoichiometric
- Perfect
Combustion
- Carbon dioxide (CO2)
- Water (H2O) vapor
Products of Combustion
Theoretical point at which the ratio of fuel to oxygen results in this.
Complete Combustion
When all the carbon in the fuel forms CO2 and all the hydrogen forms H2O.
Stoichiometric Combustion
When all the fuel and all the oxygen are totally consumed.
- Can only occur in a controlled lab environment
Perfect Combustion
Operate as closely as possible to stoichiometric combustion to maximize efficiency and the reduction of environmentally harmful emissions that are the products of incomplete combustion.
Goal of All Combustion Processes
Occurs when complete oxidation of the combustible material does not occur (i.e. the combustible does not unite with the maximum amount of oxygen).
- When lack of oxygen results in one carbon atom uniting with only one atom of oxygen, carbon monoxide (CO) forms instead of carbon dioxide.
- Oxygen insufficiency can also result in the production of smoke, the visible suspension of carbon or other particles in the air emitted during the process.
Incomplete Combustion
Amount of air that must be added to make certain all energy is retrieved.
- Combustion process must be adjusted so the proper amount is present.
- Level is set based on variables such as type of fuel supply (fuel+cremation container+remains), changes in atmospheric pressure, and other factors.
Excess Air
From the ignition source to the adjacent layer of gas mixture.
- Each point of the burning layer serves as ignition for the next adjacent layer, and so forth.
Spread of Combustion
When total heat energies of the reactants and the total heat energies of the products reach equilibrium.
End of Combustion
The substances that take part in and undergo change during a chemical reaction.
Reactants
Obtain optimal efficiency is ensured by proper ratio and distribution of the fuel and the oxidant in the incinerator, by regulating the conditions for heat transfer from the combustion products, and by appropriate aerodynamics of gas flow in the device.
- To a certain extent, radiation contributes to the heat exchange.
Control of the Combustion Process
The transfer of heat in the form of waves or rays through space.
Radiation
Equipment used to accomplish the reduction of combustible material by direct combustion through a sequence of steps.
- Primary process- drying during the initial heating of the combustible material to drive off moisture, volatilization of the vapors and gases which occur as the temperature of the material raises, combustion of the change, and burnout of the solids.
- Secondary process- Combustion of the vapors, gases, and particulates driven off during the primary process.
Incinerators
Portable, packaged, completely assembled direct-fed incinerators
- Suitable for type 2 waste
- 25 lbs/hr burning capacity
Class I Incinerator
Portable, packaged or job assembled direct-fed incinerators.
- Type 3 waste
- 25 lbs/hr up to but not including 75/hr burning rate
Class IA Incinerator
Flue-fed, single chamber incinerators.
- Type 2 waste
Class II Incinerator
- Chute fed
- Multiple chambers
- Type 1, non-industrial or Type 2 waste
Class IIA Incinerator
Direct-fed incinerators
- Type o, Type 1, or Type 2 waste
- 100 lbs/hr or over burning rate
Class III Incinerator
Direct-fed incinerators
- Type 3 waste
- 75 lbs/hr or over burning rate
Class IV Incinerators
Municipal incinerators
- Type 0, type 1. type 2, or type 3 wastes or a combination of all four wastes
- Rated in tons/hr/24 hrs.
Class V Incinerators
Crematory and pathological incinerators.
- Type 4 waste
Class VI Incinerators
Incinerators designed for specific by-product wastes
- Type 5 or 6
Class VII Incinerators
Municipal sewage sludge incinerators
- Type 7 waste
Class VIII Incinerators
Trash
- Mixture of combustible waste from commercial and industrial activities
- Paper, cardboard, wood, boxes, and combustible floor sweepings containing up to 10-20% petrochemical waste (plastic), 5% noncombustibles, and 10% moisture by weight
- Average heating value 8,500-9,500 BTU/lb
Type 0 Waste
The amount of heat.
Heating Value
Rubbish
- Mixture of combustible waste from commercial and industrial activities
- Paper, cardboard, wood scrap, foliage, floor sweepings containing up to 10% petrochemical waste, 5% non-combustibles, and 10% moisture by weight.
- Average heating value 6,500-7,000 BTU/lb
Type 1 Waste
Refuse
- Evenly distributed mixture of rubbish and garbage as usually received in municipal waste (residential sources)
- Contain up to 7% noncombustible solids, 50% moisture content by weight.
- Average heating value= 4,300-5,000 BTU/lb.
Type 2 Waste