Case Study

Calorific Value Determination for Animal Faeces 

Sample Preparation

Prepare the animal faeces sample according to ISO 6498 Animal feeding stuffs-Guidelines for sample preparation

1. For feedstuffs with higher moisture content(dry mass fraction<85%), partial drying below 55⁰C to 60⁰C can be necessary before grinding. 
2. Grind the laboratory sample so that it passes completely through a sieve with 1mm apertures 
3. Mix the sample, preferably by mechanical means, divide the mass with riffle divider or rotational divider. 
4. By use of the briquette press or similar tool, press 0.5g-5g of the test sample to form a pellet, the mass of the test portion depends on the calorific value of the calorimeter. 

Instrument
5E-C5500 Automatic Calorimeter

Instrument Settings
Oxygen Gas: purity 99.5%
Cylinder Pressure:  ≥4.5Mpa
Work Pressure:  2.8~3.0Mpa
Pure Water : 100ml Benzoic acid:26467J/g
Calibration Standard: ISO 9831
Nominal Sample Weight: 1g±0.1g
Analysis Method(Normal/Quick) : Normal Analysis Time: 12 minutes

Special Modifications to Unit
None

Method Approval
ISO 9831 Animal feeding stuffs, animal products, and faeces or urine – Determination of gross calorific value – Bomb calorimeter method

Procedure
1. Prepare instrument as outlined in the operator’s instruction manual ( Routine check for ambient temp. ,oxygen bomb leak, cylinder pressure, bucket leak ,etc.).
2. Run analysis as preheating for 25mins(with bomb in bucket)
3. Run analysis as heat capacity calibration with dummy sample (twice for benzoic acid standard)
4. Run analysis as Heat capacity calibration with ten benzoic acid samples, calculate and save result to finish the heat capacity calibration
5. Run 6 sample analyses

6. 2 samples of calibration substance to check the calibration;
7. Repetition of point 5 to point 6 until all samples are processed;

Note: Do Calibrating refer to operator’s instruction manual for details.

Typical Results

CodeNameMass(g)Temp. Rise(K)Heat Capacity(J/K)Qb(MJ/kg)
1J.Q male1.10131.8492984816.678
2J.Q male1.07431.8110984816.759
3J.Q female0.93331.6092984817.107
4J.Q female0.93221.6075984817.130
5Benzoic0.99942.6590984826.470
6Benzoic0.99102.6386984826.493