1 HVACR215 – Mechanical for Oil Oil Combustion

2 Combustion The burning of a substance. Rapid Oxidation The burning of a substance. Rapid Oxidation

3 Oxidation All matter is made of of elements. One of the most basic elements on earth is oxygen. Many materials react with oxygen, this is a process called oxidation. –Rusting of metal is a common form of this process. All matter is made of of elements. One of the most basic elements on earth is oxygen. Many materials react with oxygen, this is a process called oxidation. –Rusting of metal is a common form of this process.

4 Oxidation Sometimes heat must be added for this process to take place, and sometimes heat is given off from the oxidation process.

5 Combustion When oxygen acts with a substance to produce large amounts of heat rapidly (and usually light), the process is called “combustion” or burning. With enough air present fuel gases will burn in their normal, gaseous state. When oxygen acts with a substance to produce large amounts of heat rapidly (and usually light), the process is called “combustion” or burning. With enough air present fuel gases will burn in their normal, gaseous state.

6 Combustion Solid or liquid fuels, on the other hand, must be changed to a gas first before they will burn. Usually heat is required to make this transaction of solids to gas or liquids to gas. Solid or liquid fuels, on the other hand, must be changed to a gas first before they will burn. Usually heat is required to make this transaction of solids to gas or liquids to gas.

7 Requirements for combustion Three things must be available for combustion to take place: –Fuel –Oxygen (air) –Heat Take away any one of these and burning will stop. Three things must be available for combustion to take place: –Fuel –Oxygen (air) –Heat Take away any one of these and burning will stop.

8 Triangle of Combustion Fuel Air Heat

9 Fuel Oil and Air Fuel oil is 85% Carbon and 15% hydrogen. Air is 21% oxygen and 79% nitrogen. You are in control of the combustion process because you can regulate both the fuel and the air. Fuel oil is 85% Carbon and 15% hydrogen. Air is 21% oxygen and 79% nitrogen. You are in control of the combustion process because you can regulate both the fuel and the air.

10 Example of requirements Take a wood burning fire as an example. –Throw a blanket over fire and cut off air, fire will go out. –Drag all the wood away from the fire and the fire goes out. –Throw water on fire, chill the wood temp, and fire goes out. Take a wood burning fire as an example. –Throw a blanket over fire and cut off air, fire will go out. –Drag all the wood away from the fire and the fire goes out. –Throw water on fire, chill the wood temp, and fire goes out.

11 By Products of combustion Combustion will give off the following by-products: –Water Vapor (H2O) –Carbon Monoxide (CO) –Carbon Dioxide (CO2) –Carbon (C ) - In the form of soot Combustion will give off the following by-products: –Water Vapor (H2O) –Carbon Monoxide (CO) –Carbon Dioxide (CO2) –Carbon (C ) - In the form of soot

12 Oil Combustion The air and fuel mixture must be exact. If the mixture is correct then proper combustion is achieved. If the mixture is incorrect then you have poor combustion. The air and fuel mixture must be exact. If the mixture is correct then proper combustion is achieved. If the mixture is incorrect then you have poor combustion.

13 Proper Combustions More heat per dollar Clean exhaust Clean furnace or boiler Proper efficiency More heat per dollar Clean exhaust Clean furnace or boiler Proper efficiency

14 Poor Combustion Less Heat per Dollar, not getting 140,000 btus/gallon More smoke and soot More furnace or boiler maintenance Unburned fuel –Equals poor efficiency and waste of money Less Heat per Dollar, not getting 140,000 btus/gallon More smoke and soot More furnace or boiler maintenance Unburned fuel –Equals poor efficiency and waste of money

15 Physical Requirements for burning Fuel oil must be in a vapor form to produce flame. Remember a solid or liquid can not burn. An example of this is a pot of oil at room temperature. –Will not burn –Must be vaporized first Fuel oil must be in a vapor form to produce flame. Remember a solid or liquid can not burn. An example of this is a pot of oil at room temperature. –Will not burn –Must be vaporized first

16 Burner Designs The oil burner has the primary function of vaporizing the fuel oil. There are different types of burners available. –Pressure atomizing or gun type –Rotary cup –Vaporizing –Pot burners The oil burner has the primary function of vaporizing the fuel oil. There are different types of burners available. –Pressure atomizing or gun type –Rotary cup –Vaporizing –Pot burners

17 Pot Type Burner The oil vapors burn on top of an oil puddle. The heat from the Fire creates more vapor.

18 Gun Type Burners The most frequent, all newer equipment. Oil and air are forced into the burner head for mixing and ignition. Two types of gun-type burners. –Low Pressure –High Pressure The most frequent, all newer equipment. Oil and air are forced into the burner head for mixing and ignition. Two types of gun-type burners. –Low Pressure –High Pressure

19 Gun Type Burner

20 Low Pressure Type

21 Low pressure type Primary air and Oil are forced into the nozzle and then mixed with secondary air for combustion. This type burner not found very often any longer. Primary air and Oil are forced into the nozzle and then mixed with secondary air for combustion. This type burner not found very often any longer.

22 High Pressure Type

23 High Pressure Type Primary air and oil are kept separate until they are mixed at the end of the air tube. Oil supply is at much higher pressure, usually over 100 psi. This is the type of most modern burners. Primary air and oil are kept separate until they are mixed at the end of the air tube. Oil supply is at much higher pressure, usually over 100 psi. This is the type of most modern burners.

24 Air Supply and Mixing Air is supplied by the burner fan. Air is adjustable by the burner adjustments (primary and secondary) Air is brought into the process from the air surrounding the furnace or boiler, room air. Air is supplied by the burner fan. Air is adjustable by the burner adjustments (primary and secondary) Air is brought into the process from the air surrounding the furnace or boiler, room air.

25 Fuel and air mixing parts Fuel and air is mixed by one of more of the following parts: –Turbulators –End Cones –Spinners –Flame Retention Heads All are designed for the mixing of droplets of oil and air. Fuel and air is mixed by one of more of the following parts: –Turbulators –End Cones –Spinners –Flame Retention Heads All are designed for the mixing of droplets of oil and air.

26 Poor mixing Poor mixing of air and oil equals: –Incomplete combustion –Smokey fire Poor mixing of air and oil equals: –Incomplete combustion –Smokey fire

27 Factors Controlling Mix Several factors control the fuel and air mix. We are going to talk more about these. –Spray pattern must be correct for burner –Spray angle must be correct for burner –Air flow must match both angle and pattern –All nozzles must match the manufactures specification. Several factors control the fuel and air mix. We are going to talk more about these. –Spray pattern must be correct for burner –Spray angle must be correct for burner –Air flow must match both angle and pattern –All nozzles must match the manufactures specification.

28 Burner Design The burner design and parts are important to the proper operation. –Flame Retention Heads –Internal Recirculation –End cones –Air Swirl The burner design and parts are important to the proper operation. –Flame Retention Heads –Internal Recirculation –End cones –Air Swirl

29 Burner design The burner design varies by manufacturer.