Calorific Value of Materials via Bomb Calorimetry

bomb calorimetry

Reviewing the Bomb Calorimetry method of standard ISO 1716 & ASTM D240.

Nowadays, knowing the energy released in a material during combustion or pyrolysis is crucial for the Waste Management, Recycling and Energy Recovery from waste sectors. More precisely, while most of the plastics can be easily mechanically or chemically recycled, some of them mainly films and thermosets follow the pyrolysis route to recover the energy released.

The science measuring the energy released during combustion is Calorimetry. The instruments used for such measurements are known as calorimeters. The most popular units are the oxygen bomb calorimeters, which are the standard instruments for measuring calorific values of solid and liquid combustible samples following internationally accepted methods such as the BS EN ISO 1716 and/or ASTM D240.

The calorific value via the Oxygen bomb calorimeter is measured by the heat obtained from the sample, compared with the heat obtained from combustion of a reference material such as benzoic acid. A known amount of sample is burnt in a high pressure oxygen atmosphere within a vessel or “bomb”. The energy released by this combustion is captured by the calorimeter unit and the resulting temperature change within the absorbing medium is recorded. The heat of combustion of the sample is then calculated by multiplying the temperature rise in the calorimeter by a previously determined energy equivalent or heat capacity determined from previous tests with a reference material.

For example, several pyrolysis products from a Middle Eastern petrochemical company were tested for their calorific value to determine the energy released. For this analysis we used a state-of-the-art Oxygen Bomb Calorimeter, CAL3KS from DDS calorimeters. The char samples had been previously pyrolyzed at 900 °C for 10 minutes. A few milligrams of a solid material were added in the pressurized vessel and placed in the calorimeter box for testing. The calibrated unit then displayed the result in KJ/g only 2 minutes after the start of the test. No previous samples preparation was necessary.

Bomb calorimetry is just one of the new methods added in the analytical testing family a part the wider Material Testing and Development Laboratory in Grangemouth, UK. Should you have any questions and/or inquiries regarding our calorific test or any other capabilities, contact us here. Our highly trained chemists or material scientists and engineers will be happy to assist you.

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