Methane number
The methane number (abbreviated MZ ) is a measure of the knock resistance when burning gas mixtures, comparable to the octane number and the cetane number . The MZ indicates the percentage mixing ratio of a reference fuel, consisting of methane and hydrogen . MZ 100 is only methane and knock-proof, MZ 0 is only hydrogen and knock-resistant. In between are the comparison mixtures with which the gas mixture to be tested is compared in a test engine and its MZ is thus determined. An MZ 80 of a gas mixture means that it has the same knock properties as the comparison mixture consisting of 80% methane and 20% hydrogen.
The lower the methane number, the lower the knock resistance, which increases the risk of self-ignition and knocking of the engine. The higher the methane number, the more knock-resistant the gas mixture.
The MZ measuring method requires an air ratio of = 1 in the test engine.
| gas | CH 4 | H 2 | C 2 H 6 | C 3 H 8 | C 4 H 10 | CO | CO 2 | N 2 | O 2 | H 2 O | rest |
|---|---|---|---|---|---|---|---|---|---|---|---|
| natural gas | 88.5 | 4.7 | 1.6 | 0.2 | 5 | ||||||
| Sewage gas | 60 | 3 | 32 | 5 | |||||||
| Landfill gas | 50 | 40 | 9 | 1 | |||||||
| Coke oven gas | 31 | 55 | 8th | 1.2 | 3.8 | 1 | |||||
| Wood gas | 3 | 7th | 2 | 17th | 15th | 56 | |||||
| Biogas | 50-75 | <1 | 25-45 | 1 | 0.3 | 2-7 | NH 3 , H 2 S |
For gas mixtures made up of three components, the methane number can be read from triangular diagrams, e.g. B. for sewage gases, consisting of methane, carbon dioxide and nitrogen .
The methane number can also be determined arithmetically, for which a number of computer programs are available.
Natural gas: MZ> 80; Propane: MZ = 35; Landfill gas: MZ> 100
Individual evidence
- ↑ Klaus Mollenhauer, Helmut Tschöke: Manual Diesel Engines . Springer, Berlin 2007. ISBN 3540412395 , page 130 .
- ↑ Printing errors in the original text, MZ between 120 and 150
- ↑ Klaus Mollenhauer, Helmut Tschöke: Manual Diesel Engines . Springer, Berlin 2007. ISBN 3540412395 , page 131 .
- ↑ Examples: Archived copy ( Memento of the original dated March 30, 2005 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. P. 63.
