Linde air liquefaction plant at the Paris World’s Fair in 1900. |
The company soon delivered 72 small liquefaction plants to scientific institutions and used them for public demonstrations. In Munich in 1898 at the "Second Engine and Industrial Machine Exhibition", von Linde presented a small plant in the Diesel Pavilion driven by a 10 hp diesel engine - an impressive demonstration of the two greatest achievements of that time in the area of thermal engineering. |
And at the 1900 Paris World’s Fair, Linde’s air liquefaction plant received the Grand Prix, the most coveted prize of the exhibition. These public demonstrations - even Kaiser Wilhelm II came to see the machinery in Berlin - were possible since, with the new design, Linde had reduced the chilling time until liquefaction from 15 hours to just one hour. Further improvements later reduced the process to just 15 minutes.
Years of patience
A commercially viable method of separating oxygen from liquid air would, however, take some time. Von Linde made his first attempts with "fractionation": Since oxygen boils at minus 183 degrees Celsius, and nitrogen at minus 196 degrees Celsius, when liquid air is heated, nitrogen evaporates 13 degrees Celsius sooner than oxygen and can be separated - "fractionated" - from the rest of the gas mixture.
However, because the temperature difference was so slight, not all of the nitrogen was released using the fractionation method. In fact a considerable portion remained in the subsequently evaporating oxygen. Only a 50-50 mixture could be economically produced in this way - the "Linde Air."
At first it looked as if "Linde Air" would have a market with a strong future, mainly in the chemical industry. "Linde Air" also appeared to promise sales opportunities for use as an explosive. Test blasts during the construction of the Swiss Simplon Tunnel strengthened this hope. But this activity was ceased after the First World War