10-Combustion Lab Unit Liquid Burner

Faculty of Chemical & Natural Resources Engineering

BKG3741 Fuel and Combustion Lab

Experiment 7COMBUSTION LAB UNIT -

GAS BURNER & LIQUID BURNER

NameMatric No.GroupProgramSectionDate

Sem. 11 - Session 2012/2013

BKG3741 – Fuel and Combustion Lab Sem II-2012/2013

INTRODUCTION - C492 COMBUSTION LABORATORY UNIT

This unit enables studies into many aspects of combustion and burner operation using the optional burners or any suitable commercially available oil or gas burner up to 150 kW.

The four large observation windows fitted in the frame mounted, water cooled, combustion chamber provide an excellent flame demonstration facility. The full instrumentation and safety features allow supervised student operation over a wide range of air/fuel ratios and different fuels.

Figure 1: C492 Combustion Laboratory Unit

1.0 OBJECTIVES

Investigation of Air/Fuel Ratio and Stoichiometric Condition.

Any hydrocarbon fuel has a condition of perfect combustion, in which the oxygen is consumed. The stoichiometric air/fuel ratio is different for each fuel depending on its chemical composition. This experiment is to set the burner to a mid range of fuel flow, which remains constant, and

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then alter the air/fuel ratio throughout the range possible to achieve combustion.

2.0 GENERAL DESCRIPTION

2.1 Unit Construction

Figure 2: Control Panel Layout C492

1. Main Switch 8. Water Flow Switch2. Burner Power Supply 9. Water Outlet Temperature3. Burner On 10. Water Temperature

Control4. Burner On/Off 11. Water Temperature

Control5. Burner Lockout 12. Oil Flowmeter6. Temperature Indicator 13. Gas Flowrate Timer7. Cooling Water Flowmeter

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Figure 1: C492 Combustion Laboratory Unit

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3.0 OPERATING PROCEDUR – GAS & OIL BURNER

3.1 OPERATING PROCEDURE – GAS BURNER

3.0 OPERATING PROCEDURE – OIL BURNER

3.1 SETTING UP OIL BURNER

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1. Fit the gas burner onto the four mounting studs with four M8 nuts. Ensure the gasket is not over tighten (just more than finger tight).

2. Connect and screw the 7 pin plug to the burner power socket.

3. Plug the 2 pin plug flow meter sensor lead to the socket at control panel.

4. Remove the blanking cap from oil pump and unscrew the hose coupling at right sided vertical plate of the frame. Loosely screw hose to the oil pump suction port.

5. Place the drip tray under the burner on the horizontal plate of the frame.

6. Ensure fuel in the tank is sufficient for the test.

3.2 STARTING THE OIL BURNER

1. Switch on the main isolator and main switch on the panel. ( Instrumentation should light)

2. Turn on main isolating valve and the valve at rear unit for water supply. Slowly turn the cooling water flow control anticlockwise until 200 g/s. Both two lamps change to green.

3. Ensure to set the dial of the water temperature control at 80˚C or above.

4. Turn the three way valve to the desired fuel tank position.

5. Open the isolating valve at the front of the unit.6. Squeeze the priming pump for few times to purge the

line and then tighten the coupling. 7. Set the burner air control damper at position no 1-2.8. Press the green burner on/off button 1. The burner fan

will start.9. Ignition spark will be heard, gently squeeze the priming

pump and the burner should light up and then release the priming pump.

10. The pump pressure will indicate the delivery pressure and the green burner on lamp will illuminate

3.3 EMERGENCY STOP FOR THE OIL BURNER

1. Press the red burner on/off button O on the control panel.

3.4 SHUTTING DOWN THE OIL BURNER

1. Turn off the oil isolating valve.2. Turn off the water flow at cooling water flow valve,

water isolating valve and the main valve.

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3. Switch off the unit at main switch on the control panel.

4.0 Safety Measures

Unit should be operated in a well ventilated area and sited well away from inflammable or heat sensitive material.

Do not allow the unit to run with the gas control valve open if no flame has been established.

The gas burner control system is more complex than the oil burner due to potentially hazardous and explosive nature of the fuel. Special care need to be taken during handling this system.

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C492- OBSERVATIONS OILDate: Fuel: Stoichiometric A/F: (by volume) Relative Density: (SG)Burner: Stoichiometric A/F: (by mass) Ambient Temperature: (C)Ambient Pressure: (mbar) Nozzle 1.35 / 2.0 Usgal/hr

TEST NO. 1 2 3 4 5 6 7 8 9 10Pump Pressure ( psi)Fan Damper Setting (No)Diffuser Setting (No)Fuel Flow Rate Indicated (L/Hr)Cooling Water Flowrate (g/s)Cooling Water Inlet Temp. t1 (C)Cooling Water Outlet Temp. t2 (C)Air Inlet Temperature t3 (C)Exhaust Temperature t4 (C)O2 (%)CO2 (%)CO (ppm)Excess Air (%)Flame Temperature t5 (C)Flame Color Flame Length (cm)Smoke NoEfficiency Nett (%)C492- DERIVED RESULTS OIL


Date: Fuel: Stoichiometric A/F: (by volume) Density of Gas: (kg/m3)Burner: Stoichiometric A/F: (by mass) AmbientTemperature: (C)Ambient Pressure: (mbar) Nozzle 1.35 / 2.0 Usgal/hr

TEST NO. 1 2 3 4 5 6 7 8 9 10Corrected Fuel Flow Rate (L/Hr)A/Fl Ratio (by Volume) (vol/vol)Air Flow Rate (by Volume) (L/Hr)Mass Fuel Flow Rate (kg/Hr)A/F Ratio (by mass) (kg/kg)Air Flow Rate (by mass) (kg/Hr)Heat Input (Qin ) (kW)Flue – Useful a (kW)Flue – Unburnt b (W)Flue – Vapor c (kW)Total Heat to Flue (kW)d= (a+b+c)Heat to Water e (kW)Heat Output (Qout) =(d+e) (kW)Difference (Qin –Qout)/Qin (%)

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6.0 EXPERIMENT

6.1 Procedure for Oil Burner:1. Ensure the 1.35 USgall/hr nozzle is fitted.2. Start the gas burner firing.3. Set constantly the oil pump pressure for the wide range of

air/fuel ratio ( approximately 50 kW heat input, 8 Bar, 100 psi on the 1.3 USgall/hr nozzle)

4. Adjust the cooling water flow and then keep it constant for outlet temperature (T2) between 60 and 80 ˚C.

5. Adjust the damper to the minimum which sustain combustion

6. Allow conditions to stabilize and record the readings on the observation sheet.

7. Increase the air damper position by one graduation.8. Again, allow the condition to stabilize and record the

readings.9. Increase the air flow in stages until maximum setting is

reached or combustion cannot be sustained.10. Shut down the burner.11. Process the readings as given on the Derived Results

Sheet.The O2, CO2 and CO values are obtained from the standard air analyzer supplied.

6.3. Analysis & Discussions:

1. Plot the graphs for Excessive Air (%) Vs. 02 and CO2(%).2. Complete the calculation in the tables for both mass and

volume. 3. Comments on the finding of the air/fuel ratio for the

combustion.


Sample Calculation

Gas Flow Rate (Volume)

Air Fuel Ratio (Volume) Stoichiometric A/F by volume = 24 : 1Excess Air ( ) = 49.7 % (from Analyzer)

Air Fuel Ratio (Volume) = 35.93 : 1

Air Flow Rate (Volume)= Gas Flow Rate x A/F vol

Gas Flow Rate (Mass)= Volume Gas Flow Rate x Density of Fuel

Air Fuel Ratio (Mass)= 15.6 : 1

Air Fuel Ratio (Mass) = 23.35: 1

Air Flow Rate (Mass)= Gas Flow Rate x A/F vol

Heat Input= Mass Gas Flow Rate x Gross Calorific Value (Fuel)

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Attachment

Fuel Stoichiometri Stoichiometri Theoritica Gross Chemica

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c A/F by Volume

c A/F by Mass l Maximum CO2 (%)

Calorific Value (MJ/Kg)

l Formula

Natural Gas

9.81 : 1 17.16 : 1 11.8 55.00 CH4

Propane 24 : 1 1.6 : 1 13.8 50.00 C3H8Butane 30 : 1 14.8 : 1 14.1 49.5 C4H10Kerosene

9.48 : 1 14.7 : 1 15.4 46.2 -

Gas Oil 9.82 : 1 14.4 : 1 15.4 45.5 -

Conversion Factor10 mm H20 = 1 cm H20 = 1 mbar1 ft3 = 0.02832 m3

1 Imperial gallon = 4.546 Litre1 US gallon = 3.785 Litre

Oil Flowmeter Correction Factor = Display x 1.1 ( Kerosene)= Display x 1.0 (Gas Oil)

Cpg for Exhaust gas taken as 1.15 kJ/kgK ( for 750 EC)

Typical Values of density (Kg/m3)

Item DensityKerosene 790Gas Oil 835Propane 1.85Butane 2.45Natural Gas 0.68

Molecular Weight of O2 = 32Molecular Weight of H2 = 2Molecular Weight of C = 12Molecular Weight of N2 = 28Molecular Weight of H2O = 18

Air = 79 % N2, 21 % 02 ( by volume) 76.7 % N2, 23.3 % O2 (by mass)

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10-Combustion Lab Unit Liquid Burner