Abstract: A method for compressing a gas by means of a multi-stage piston compressor is disclosed, wherein, if an inlet pressure of a first compression stage exceeds a threshold value, the gas is at least partially, in particular completely, branched off before the first compression stage and fed to a second compression stage, which directly follows the first compression stage. A computing unit for performing the method to such a multi-stage piston compressor are further disclosed.

Abstract: The invention relates to a method for producing a metallic workpiece in layers by means of additive manufacturing, metallurgical layers of the workpiece being produced by providing a metal material in manufacturing chamber for each metallurgical layer and applying a laser beam to said metal material, and providing a gas atmosphere in the manufacturing chamber during the application of the laser beam to the layers of the metal material, characterized in that a part of the gas atmosphere is drawn off from the manufacturing chamber as a gas stream, at least one parameter of the gas stream and/or the gas atmosphere being determined and being compared with a desired value. Depending on the comparison of the parameter with the desired value the gas stream is fed back to the manufacturing chamber and a process gas is supplied to the manufacturing chamber.

Abstract: The invention relates to a plate heat exchanger 1 with at least two cuboidal modules 1a, 1b. The two modules 1a and 1b are cuboidal and are each closed to the outside by cover sheets 5. The two modules 1a and 1b are arranged such that in each case, cover sheets 9a and 9b of the same size are directly adjacent. On the contact surfaces, sections 20a, 20b are welded that prevent movement of the two modules 1a, 1b perpendicular to the contact surfaces 9a, 9b either alone or with an additional formed part 50.

Abstract: The invention relates to a method and apparatus for producing pressurized oxygen by low-temperature separation of air in a distillation column system having a low-pressure column and a high-pressure column. All of the feed air is compressed to a first air pressure, at least 4 bar above the operating pressure of the high-pressure column. A first partial stream of the feed air, compressed to the first air pressure, is further compressed in a secondary compressor to a second higher air pressure, before being (pseudo-)liquefied and is introduced into the distillation system. A second partial stream of the feed air, compressed to the first air pressure, is cooled and depressurized in an expander, which drives the secondary compressor. A return stream is branched off from the (pseudo-)liquefied first partial stream, depressurized, heated and then introduced to the first partial stream upstream from the secondary compressor.

Abstract: The invention relates to a method for separating off carbon dioxide from a gas mixture containing hydrogen, carbon monoxide and carbon dioxide, which gas mixture is produced as residual gas in an alcohol synthesis. The residual gas is subjected to a physical gas scrubbing in which carbon dioxide is scrubbed out of the residual gas in an absorption step by means of a low-temperature alcohol used as the scrubbing medium.

Abstract: The invention relates to a column comprising a jacket that bounds at least a first jacket space (M) and a second jacket space arranged thereabove along the longitudinal axis (L). The e first jacket space is separated from the second jacket space by a gas-permeable first chimney tray. A gaseous phase flows upward into the first jacket space, through the first chimney tray into the second jacket space, and then flows upward into the second jacket space. In the first jacket space the gaseous phase (M), in counter-current flow, contacts a first liquid washing agent, and in the second jacket space the gaseous phase, in counter-current flow, contacts a second liquid washing agent. The first chimney tray has a separator for separating the second washing agent, which separates the second washing agent (W?) and directs it into the second jacket space. The invention further relates to an apparatus comprising the column and a method for separating CO2 from a gaseous phase.

Abstract: The invention relates to a device (column) for bringing about a phase contact between a liquid phase and a gaseous phase, in particular a material exchange column, comprising: a shell, which extends along a longitudinal axis and bounds a shell space, at least a first circular tray, arranged in the shell space, for taking up the liquid phase, which extends crosswise to the longitudinal axis, whereby the at least one first tray has through openings for passage of a gaseous phase, so that the gaseous phase can come into phase contact with the liquid phase that is located on the at least one first tray. According to the invention, a large number of sealing weirs projecting from the first tray along the longitudinal axis are provided, which extend in each case along a radial direction of the at least one first tray, so that the first tray is divided into a corresponding plurality of sectors. In addition, the invention relates to an apparatus comprising such a device and a floatable carrier.

Abstract: The invention relates to a column, with a jacket, extending along a longitudinal axis, which jacket bounds a first jacket space and a second jacket space arranged over it along the longitudinal axis, a chimney tray, extending crosswise to the longitudinal axis, that separates the two jacket spaces from one another. The at least a first chimney extends from the tray along the longitudinal axis, and projects into the second jacket space. The chimney has a peripheral wall defining an opening, via which the two jacket spaces are connected to one another for gas feed, and a chimney top. On the peripheral wall, a flat impact element is arranged tilted toward the longitudinal axis in such a way that a liquid phase flowing downward from the chimney top along the longitudinal axis strikes the flat impact element diminishing the momentum input of the liquid phase that stands on the chimney tray.

Abstract: The invention relates to a method for recovering sulphur from a sour gas containing hydrogen sulphide and carbon dioxide, comprising: oxidation of the sour gas, wherein a part of the hydrogen sulphide is oxidized to sulphur dioxide and water, reaction of the resulting sulphur dioxide with the residual hydrogen sulphide to elementary sulphur, and removal of elementary sulphur. According to the invention carbon dioxide and/or carbon dioxide generated by oxidation of the sour gas is compressed, and at least a part of the carbon dioxide is injected into an oil well. Furthermore, the invention relates to a plant suitable for performing the above method.