ED 72.19 Biomass Conversation
ED 72.19 Biomass Conversation
Lab Report No.2: Heating value of solid fuel Lab Report No.2: Heating value of solid fuelThe heating value or calorific value of a fuel is the amount of heat released during the The heating value or calorific value of a fuel is the amount of heat released during the combustion of a specified amount of it. It is measured in units of energy per unit weight: combustion of a specified amount of it. It is measured in units of energy per unit weight: normally kcal/kg, kJ/kg. The bomb calorimeter is the most common device for measuring normally kcal/kg, kJ/kg. The bomb calorimeter is the most common device for measuring the heating value or calorific value of a solid fuel.
the heating value or calorific value of a solid fuel.
Objectives Objectives
To determine the heating value of solid fuel. To determine the heating value of solid fuel.
Theory Theory
The amount of heat available from any solid fuel can be determined by testing a small The amount of heat available from any solid fuel can be determined by testing a small sample of the fuel in a bomb calorimeter. The test sample such as charcoal, wood is made sample of the fuel in a bomb calorimeter. The test sample such as charcoal, wood is made to burn completely in a bomb which pressurize with pure oxygen so that the heat
to burn completely in a bomb which pressurize with pure oxygen so that the heat developed by the combustion is absorbed by a definite mass of water. This causes a developed by the combustion is absorbed by a definite mass of water. This causes a
measurable rise in the water temperature, from which it is possible to calculate the heating measurable rise in the water temperature, from which it is possible to calculate the heating value.
value.
Apparatus Apparatus
-- G. G. CuCussssonons s bobomb mb cacaloloririmemeteter r
Specification Specification
P
Poowweer r ssuupppplly y rereqquuiirreemmeennt t :: 222200VV, , 550 0 HHz, z, ssiinngglle e pphhasasee M
Maannuuffaaccttuurree :: GG. . CCuussssoonnss
The bomb calorimeter made by G. Cussons is self-contained with the control unit house in The bomb calorimeter made by G. Cussons is self-contained with the control unit house in an instrument case that forms the base. The equipment includes the bomb itself, a
an instrument case that forms the base. The equipment includes the bomb itself, a calorimeter vessel, an outer double walled water vessel, electric stirrer gear, combined calorimeter vessel, an outer double walled water vessel, electric stirrer gear, combined motor gear and ignition unit. A Backman type thermometer and charging unit with motor gear and ignition unit. A Backman type thermometer and charging unit with pressure gauge to facilitate the charging of the bomb with oxygen.
pressure gauge to facilitate the charging of the bomb with oxygen.
Procedure Procedure
1.
1. MeasurMeasure moiste moisture conure content (wet btent (wet basis) anasis) and prepad prepare fuel samre fuel sample for bple for bomb calomb calorimetorimeter er test by powdering and drying at
test by powdering and drying at 105105°°C in oven at least 2 hours.C in oven at least 2 hours.
2.
2. Weigh thWeigh the empty ce empty cup and pup and put the sut the sample in tample in the cup abhe cup about 0.out 0.9-1.1 9-1.1 grams fgrams for solior solidd fuel. Weigh the sample with the cup again and weigh of the true sample can be fuel. Weigh the sample with the cup again and weigh of the true sample can be determined.
determined. 3.
3. InserInsert the fut the fuse wire ase wire about bout 7 cm. T7 cm. The wire mhe wire must noust not touct touch the cuh the cup.p. 4.
4. Fill aboFill about 10 mut 10 ml of distl of distilled watilled water in the ber in the bomb. Tomb. This is this is to obtaio obtain the hign the higher heatiher heatingng value of fuel.
value of fuel. 5.
5. AssemAssemble the boble the bomb, timb, tighten tghten the cap seche cap securely by urely by fingefinger-tight or-tight only. Cnly. Care musare must bet be taken of pilling the sample.
taken of pilling the sample. 6.
7. Measure distilled water of 2,000 ml.(2 Kg.) and pour into calorimeter bucket. The temperature of water must be 2°C below room temperature.
8. Put the bomb in the bucket, under the water level. 9. Assemble the calorimeter jacket.
10. Stir the water at lease 2 minutes before reading temperature.
11. Record water temperature at 1 minute interval for 5 minutes and then ignite the fuel.
12. Read thermometer at 1 minute interval until the maximum temperature is reached. 13. Keep on reading after the maximum point at 1 minute interval for 5 minutes.
14. Remove the bomb and release the residual pressure and take off the cap. 15. Calculate the calorific value of fuel.
Results and discussion
Table 1: Time and Temperature Reading
Test 1 (Rice Husk) Test 2 (Saw Dust)
Weight of crucible = 4.9813 g Weight of crucible = 4.9795 g Weight of crucible + Sample =
5.9817 g
Weight of crucible + Sample = 5.9969 g
Weight of Sample = 1.0004 g Weight of Sample = 1.0174 g Time (min) Temperature (°C) Time (min) Temperature (°C)
0 1.010 0 1.040 1 1.010 1 1.055 2 1.010 2 1.060 3 1.012 3 1.065 4 1.012 4 1.070 5* 1.014 5* 1.070 6 1.200 6 1.550 7 1.850 7 2.265 8 2.130 8 2.530 9 2.225 9 2.640 10 2.229 10 2.690 11 2.320 11 2.732 12 2.345 12 2.770 13 2.365 13 2.805 14 2.375 14 2.825 15 2.385 15 2.835 16 2.390 16 2.840 17** 2.392 17 2.847 18 2.392 18 2.849 19 2.392 19 2.850 20 2.392 20** 2.851 21 2.392 21 2.851 22 2.390 22 2.851 23 2.390 23 2.850 24 2.388 24 2.849 25 2.386 25 2.847 26 2.385 26 2.845 27 2.842 * Ignition Start
0 1 1 2 2 3 3 0 5 10 15 20 25 30 time (min) t e m p e r a t u r e ( 0 C ) Rice Saw
Figure 1: Time and Temperature Reading
Table 2 Higher heating value calculation
Configuration Test 1 (Rice Husk) Test 2 (Saw Dust)
n (min) 12 15 v1(°C/min) 0.000800 0.006000 v2(°C/min) 0.000778 0.001286 Trc = nv1+ (v2– v1)/2 0.009589 0.087643 Tr = Tmax – Tign 1.378000 1.781000 Tdiff = Trc+ Tr 1.387589 1.868643 WV(kg) 0.412 0.412 mwc(kg) 2 2 Mw= WV + mwc 2.412 2.412 Cpw (kJ/kgK) 4.186 4.186 Mf (kg) 1.0004 1.0174 HHVd = (mw* C pw* Tdiff ) / mf (MJ/kg) 14.00 18.54
(HHVdcalculation procedure was done by follow the British Standard No. BS 4379,
where,
n = number of minutes between the ignition and the attainment of the m aximum temperature v1= rate of temperature raise in degree per minute at the beginning of test
v2= rate of temperature fall in degree per minute at the end of test
Trc = radiation correction (°C)
Tr = raise the temperature during test (°C) Tdiff = corrected temperature rise (°C)
Tmax = maximum temperature during test (°C) Tign = Temperature at ignition started point (°C) WV = water value of the apparatus (kg)
mwc (kg) = weight of water in calorimeter (kg) Mw = total equivalent weight of water (kg)
Cpw (kJ/kgK) = specific heat of water = 4.186 kJ/kg K Mf (kg) = weight of fuel sample (g)
HHVd= higher heating value of the solid fuel (dry basis) (MJ/kg)
As shown in table1, the higher heating value of rice husk and saw dust were
determined by using of the bomb calorimeter. Figure1 shows that both water temperatures absorbed heat from rice husk and saw dust increased sharply after ignition time, and then the temperature remained about the same. Table 2 presents that higher heating value
(HHV) of rice husk and saw dust are 14.00 MJ/Kg and 18.54 MJ/Kg respectively. HHV of rice husk is less than HHV of saw dust. This result has the same trend to proximate
analysis in the experiment 1, as shown in table below.
Type of
Sample Volatile Matter (%)
Moisture Ash content (%) Fixed carbon (%) Content (%) Rice Husk 57.015 7.59 22.4 12.995 Saw Dust 71.155 10.275 3.875 14.695
