Frequently Asked Questions - Calorimeters


How does a calorimeter work?


Calorimetry is the measuring of heat quantities that are linked to biological, chemical or physical processes both exothermic as well as endothermic.IKA offers combustion calorimeters which are distinguishable by their operating modes: adiabatic, isoperibol, or
"double-dry".

When using a combustion calorimeter, the heat that is created from a sample is measured during its combustion under con-trolled conditions. In the decomposition vessel - the so-called bomb - the sample is burned with an excess of oxygen. The resulting heat is given off into the environment and measured. To prevent disruptive external temperature influences, the system is surrounded with a jacket.

The Measurement Process

About one gram of a solid or a liquid is weighed out in a crucible and placed in the “bomb”. The sample in the crucible is con-nected to the ignition wire by a cotton thread. The vessel is then filled with oxygen (30 bar) and the sample combusted. During the combustion process, the core temperature of the crucible can increase to 1,000°C. This also increases the pressure. All organic material is combusted under these conditions.The heat produced during the combustion process can now be determined. The measurement result is then designated as the calorific value.

The heat created during the burning process can be determined in different ways.



Adiabatic Measurement Method

With an adiabatic calorimeter, the temperature in the jacket (Tov) is kept the same as the temperature inside the vessel (Tiv) throughout the test. This reasonably approaches “perfect insulation”. Unlike the isoperibolic calorimeter, no correction calculations are required.


Best Suited IKA Calorimeters

C 6000 global standards Package 1/10
C 6000 global standards Package 1/12
C 6000 global standards Package 2/10
C 6000 global standards Package 2/12



Dynamic Measurement Method

The IKA dynamic processes are essentially shorter versions of the original adiabatic and/or isoperibolic measurement processes. However, the measurement results still comply with the relative standard deviation (RSD) for the official standards.

Best Suited IKA Calorimeters

C 6000 global standards Package 1/10
C 6000 global standards Package 1/12
C 6000 global standards Package 2/10
C 6000 global standards Package 2/12
C 6000 isoperibol package 1/10
C 6000 isoperibol package 1/12
C 6000 isoperibol package 2/10
C 6000 isoperibol package 2/12
C 200



Isoperibolic Measurement Method

With an isoperibolic calorimeter, the temperature in the jacket (Tov) is kept constant throughout the test. This results in a lower heat flow. Environmental factors are minimized through air-conditioning to keep the effects of room temperature fluctuations as small as possible. However, after the test, a correction factor (Regnault-Pfaundler = ξ) that takes the heat flow into account is calculated.


Best Suited IKA Calorimeters

C 6000 global standards Package 1/10
C 6000 global standards Package 1/12
C 6000 global standards Package 2/10
C 6000 global standards Package 2/12
C 6000 isoperibol package 1/10
C 6000 isoperibol package 1/12
C 6000 isoperibol package 2/10
C 6000 isoperibol package 2/12
C 200



Static Jacket Measurement Method

In the static jacket calorimeter, similar conditions occur as with the isoperibolic calorimeter, the critical difference being that the jacket is not controlled - it is static. On the C 1, the aluminum ja-cket is the pressure-retaining container. There is still an insulating layer of air around the calorimeter housing and the jacket. When the temperature profile is considered, the behavior of the C 1 is similar to that of an isoperibolic measurement process. The same correction calculation can be used here as for the isoperibolic calorimeter according to Regnault-Pfaundler


Best Suited IKA Calorimeters

C 1



Double-dry Measurement Method

With the double-dry calorimeter, the temperature increase in the decomposition vessel itself is measured. The latter is surrounded by a large aluminum jacket. The combustion heat is thus measured directly and not transferred to the water in the inner vessel, as with conventional calorimeters. This saves a lot of time. The result - depending on the chosen pre-test time - is a measurement period of just 3 minutes per test. This method is predominantly used in the waste management industry. The actual measurement process behaves similarly to an isoperibolic measurement, albeit with a comparatively very large drift in pre- and post-testing.


Best Suited IKA Calorimeters

C 7000 basic equipment set 1
C 7000 basic equipment set 2


Calorimeter Standards

ASTM - D240 Standard test method for heat of combustion of liquid hydrocarbon fuels by bomb calorimeter
ASTM - D4809 Standard test method for heat of combustion of liquid hydrocarbon fuels by bomb calorimeter (precision method)
STM – D5865 Standard test method for gross calorific value of coal and coke
ASTM – D5468 Standard test method for gross calorific and ash value of waste materials
ASTM – E711 Standard test method for gross calorific value of refuse-derived fuel by bomb calorimeter
DIN EN ISO 9831 Animal feeding stuffs, animal products and feces or urine – determination of gross calorific value
DIN EN 14582:2007 Characterization of waste - halogen and sulfur content oxygen combustion in closed systems and determination methods
DIN 51900 – 1 Testing of solid and liquid fuels - determination of gross calorific value by the bomb calorimeter and calculation of net calorific value. Part 1: Principles, appara-tus, methods
DIN 51900 – 2 Testing of solid and liquid fuels - Determination of the gross calorific value by the bomb calorimeter and calculation of the net calorific value - Part 2: Method using isoperibol ot static, jacket calorimeter
DIN 51900 – 3 Testing of solid and liquid fuels - Determination of gross calorific value by the bomb calorimeter and calculation of net calorific value - Part 3: Method using adiabatic jacket
GB/T 213 – 2008 Calorie testing method of coal
ISO 1928 Solid mineral fuels, Determination of gross calorific value by the bomb calorimetric method and calcu-lation of net calorific value
ISO 1716 Reaction to fire tests for building products
JIS M 8814 Coal and coke: determination of gross calorific value by the bomb calorimetric method and calculation of net calorific value


Frequently Asked Questions

Which calorimeter is most suitable for my application and requirements?
The main questions that should be answered are as follows:
  • 1. How many experiments do you plan on conducting in a day?
  • 2. Are there any standards that have to be followed, such as ISO, ASTM, DIN, GB, GOST etc.?
  • 3. Do samples contain halogens and sulphur and if so, what is the concentration (approximately)?
  • 4. Is it required to analyze the halogens and sulphur content after the calorimeter experiment has concluded?
  • 5. Do you prefer any of the following methods: adiabatic, isoperibol, static jacket isoperibol, dry or dynamic?

How do I know my calorimeter is still in calibration?
Most customers operate their calorimeters with control charts. After calibrating the unit, check runs are performed with benzoic acid, for instance. The results of these check runs have to match the certified calorific value of the benzoic acid within a defined range. The definition of the range is laid out in standards and the frequency of doing these checks differs from one a day, to one after and before every sample. The control charts show the performance of the unit under the previously described circumstance over a long period of time.

How often do I have to calibrate the calorimeter?
The control chart also shows when a new calibration might be required.

What are the min. and max. calorific values that I can measure with the calorimeter?
The max. allowed energy input into our calorimeters is 40,000 J. The calorific value of a sample is always expressed in energy per weight (J/g). Based on that information, you can adjust the weight of your sample such that it does not exceed 40,000 J. The energy amount created by the sample should not be significantly higher than the one obtained during calibration with benzoic acid. Our calorimeters do have a high measuring sensitivity and can detect low quantities of energy. For example, the ignition energy of 70 J can be measured with an absolute error of ± 20 J. The relative error rises naturally (± 30%) hyperbolically the smaller the energy input is. If your sample has a very low calorific value you can also use combustion aids, since they add energy to the calorimeter to minimize the error.

When do I have to send in the decomposition vessel for high pressure inspection at IKA?
We recommend checking the vessel after 1000 experiments or after 1 year of operation, whichever comes first. During the overall inspection process we perform both a high pressure and an operating pressure test. A new certificate will be issued for the vessel after it has passed both of these tests. More detailed information can be found in the manual of your calorimeter and/ or the manual of your decomposition vessel. Alternatively, you can always contact your local service department for further information and assistance.

Where do I find a list of spare parts and how many of these do I need?
We offer sets of spare parts that include parts for 1000 experiments e.g. 1 year operation. The actual amount of spare parts can vary based on the application. If a specific spare part is required, you can find further information in the service section of the operating manual. In addition, under the “Service” section of our website (www.ika.com), you can download service drawings with detailed descriptions of each part. Alternatively, you can always contact our service department for further information and assistance.

How can I get the gross and net calorific value – easily explained? A calorimeter measures the preliminary gross calorific value of the sample. To get the gross calorific value, correction calculations are required for the acids formed during the combustion. For instance, the method of titration used to obtain the amount of nitric acid and sulphuric acid are described in detail in the standard ISO 1928. To get to the net calorific value, further corrections need to be applied concerning the amount of water that was formed during the combustion from hydrogen. Based on the state (dry, analytical moisture, as received) your sample was in before combustion, further corrections may apply. Moistures are determined by drying the samples. The Hydrogen content is usually measured with an elemental analyzer. For a more detailed explanation, we ask you to study the standards you might have to use depending on your application requirements.




IKA privacy settings
We use cookies on our website. Some are necessary, while others help us to improve the website and its functionality for you. You can accept them or adjust your cookie settings. You can find more information in our Privacy Policy.
Here you can customize your cookie settings
Necessary
Statistics
Marketing
More Options
Save
Accept all