Abstract: A finned tube for the thermal cracking of hydrocarbons in the presence of steam is defined by a tube axis and includes a plurality of inner fins. The fins are inclined at an angle of 20° to 40° in relation to the tube axis and have a flank angle of 16° to 25°.

Abstract: A finned tube for the thermal cracking of hydrocarbons in the presence of steam is defined by a tube axis and includes a plurality of inner fins. The fins are inclined at an angle of 20° to 40° in relation to the tube axis and have a flank angle of 16° to 25°.

Abstract: Metallic pipe section (10) for a pipe coil, made from one piece of pipe, comprising at least two pipe elbows (11, 12).

Abstract: In a process for the thermal cracking of hydrocarbons in the presence of steam, the charge mixture is passed through externally heated tubes with helical inner fins, and to make the temperature in the tube wall and over the tube cross section more uniform, as well as to reduce the deposition of pyrolysis coke on the tube inner wall, a swirling flow is generated in the gas mixture and is gradually merged into a core zone with a predominantly axial flow at increasing radial distance from the fins.

Abstract: Subterranean cavities which can be filled with water or brine are also used for safely depositing ecologically harmful waste. In order to introduce the waste, which must not come in contact with the water or brine, a liquid which is not miscible with water and is specifically heavier than water or brine is let in below the water or brine, where it forms a layer, and the waste is introduced into this liquid via a pipeline, whereby the waste or the mixtures of waste and binding agents must be specifically heavier than the liquid. The displaced water or brine is upwardly removed.