Linde Aktiengesellschaft

Linde Gmbh

Tuat Pham Duc

Helmut Fritz

Andreas Peschel

Gunther Schmidt

Stefanie Walter

Torben Höfel

Holger Schmigalle

Benedikt Kurz

Andreas Obermeier

Anne Spindelndreher

Desislava Tota

Paul Kuhn

The invention relates to a method () for the recovery of a separation product which contains predominantly hydrocarbons with two carbon atoms, with the use of a separation feedstock which contains predominantly methane, hydrogen and hydrocarbons with two carbon atoms, wherein the methane content of the separation feedstock is up to 20%, and the separation feedstock is provided in a gaseous state. It is provided that, at a first pressure level, the separation feedstock is partially condensed in a single step by cooling from a first temperature level to a second temperature level, thereby obtaining precisely one first liquid fraction and precisely one first gaseous fraction; at least one part of the first gaseous fraction is partially condensed in a single step through further cooling from the second temperature level to a third temperature level, thereby obtaining precisely one second liquid fraction and precisely one second gaseous fraction; at least one part of the second gaseous fraction at the second pressure level is subjected to a contraflow absorption in the contraflow to an absorption liquid containing predominantly methane, thereby obtaining precisely one third liquid fraction and precisely one third gaseous fraction; the first, the second and the third liquid fraction are at least partially combined and, at least partially, at a second pressure level above the first pressure level, subjected to a low-temperature rectification, thereby obtaining a sump liquid and an overhead gas; at least one part of the overhead gas at the second pressure level is partially condensed in a single step through further cooling from the second temperature level to the third temperature level, thereby obtaining a fourth liquid fraction and a fourth gaseous fraction; and the absorption liquid containing predominantly methane is formed through further cooling of at least a part of the fourth gaseous fraction to a fourth temperature level. A corresponding plant also forms the subject matter of the invention.

Method for producing a separation product containing predominantly hydrocarbons with two carbon atoms

Proposed is a process for producing ethylene wherein using a dehydrogenation of ethane a process gas containing at least ethane, ethylene and compounds having a lower boiling point than ethane and ethylene is formed, wherein using at least a part of the process gas a separation input is formed and subjected to a low-temperature separation () in which the separation input is cooled and in which one or more condensates are separated from the separation input, wherein the condensate(s) are at least partly subjected to a low-temperature rectification to obtain a gaseous first fraction and a liquid second fraction, wherein the gaseous first fraction contains at least the ethane and the ethylene in a lower proportion than in the separation input and the compounds having a lower boiling point than ethane and ethylene in a higher proportion than in the separation input. It is provided that the first fraction is at least partly subjected to a pressure swing adsorption () by means of which a third fraction containing predominantly or exclusively ethylene and ethane and a fourth fraction containing predominantly or exclusively methane and carbon monoxide are formed. A corresponding plant () likewise forms part of the subject matter of the present invention.

Method and plant for producing ethylene

To obtain hydrogen from a gaseous C2minus feed, it is cooled from a first to a second temperature level at a first pressure level forming one or more condensates. A gaseous remainder is cooled to a third temperature level and subjected to a counterflow absorption at the first pressure level, obtaining a top gas rich in hydrogen and methane and a sump liquid. The former is heated and subjected to pressure swing adsorption at the first pressure level, forming a product stream rich in hydrogen and depleted in or free from methane. The condensate(s) and/or the sump liquid is/are expanded to and fed into a low pressure demethanizer at the second pressure level. The counterflow absorption is carried out using fluid taken from the demethanizer at the second pressure level, compressed in gaseous form to the first pressure level and cooled to the third temperature level.

Method and system for obtaining hydrogen from a feed mixture which contains hydrogen and hydrocarbons

In a process for producing olefins, a hydrocarbon-containing feed is fed into a cracking furnace where relatively long-chain hydrocarbons of the hydrocarbon-containing feed are cracked at least partly to form shorter-chain olefins, encompassing ethylene and propylene. Cracking gas () formed during cracking is conveyed in succession through an upper section () and a lower section () of a scrubbing column () in countercurrent to a liquid scrubbing medium (), is proposed. A fraction () rich in petroleum spirit is used in the lower section () of the scrubbing column () and a water-rich fraction () is used in the upper section () of the scrubbing column () as scrubbing medium (). A plant configured for carrying out the process is likewise provided by the present invention.

Method for separating olefins with gentle cleavage

The invention describes a method for separating hydrocarbons in an installation for generating hydrocarbons from a hydrocarbon-containing charge by cleavage. The product gas of the cleavage, which contains gaseous hydrocarbons, is compressed, dried, and supplied as charge material into a separation stage (a front end C3/C4 separation). The front end C3/C4 separation comprises a C4 absorber and a depropanizer. A hydrocarbon fraction consisting of hydrocarbons having a maximum of 3 carbon atoms is obtained as a gaseous overhead product of the C4 absorber. A liquid hydrocarbon fraction consisting of hydrocarbons having at least 4 carbon atoms is obtained as a bottom product of the depropanizer. The front end C3/C4 separation comprises an additional process technological C2/C4 separation stage is arranged between the C4 absorber and the depropanizer.

Separation sequence for hydrocarbons from a gentle thermal cleavage

To decrease capital costs of crack gas treatment of the olefin plant, a method for separation of olefins reduces the units for catalytic hydrogenation. In the method, olefins having three carbon atoms are separated from olefins having four carbon atoms. Crude gas is precompressed (), precooled and dried (), and passed into a C3/C4 separation stage () comprising a C4 absorber, operating at full crude gas pressure, and a depropanizer, operated at a pressure of 8 to 12 bar. In the C3/C4 separation stage, the olefins are separated into a fraction having at most three carbon atoms (C3&#x2212;), and a fraction having at least four carbon atoms (C4+). The fraction having at most three carbon atoms is completely compressed () and passed to the catalytic hydrogenation (); the fraction having at least four carbon atoms is passed out for further processing (). The catalytic hydrogenation () yields a fraction having at least two carbon atoms (C2&#x2212;), which is passed on to the low-temperature separation, and a fraction having three carbon atoms (C3), is passed to further processing ().

Method for separation of olefins

A method is described for refrigerant supply of a low-temperature separation stage in a plant for producing olefins from hydrocarbon-containing feed (olefin plant). During the separation sequence beginning with a front end deethanizer () downstream of raw gas compressor (), precooler and dryer (), first separation is performed into an olefin fraction having at most two carbon atoms and an olefin fraction having at least three carbon atoms. The fraction having at least three carbon atoms is conducted to the further separation sequence for longer-chain olefins (). The fraction having at most two carbon atoms is conducted via a catalytic hydrogenation stage () connected in between to the low-temperature separation stage () which comprises three condensation stages in the temperature range from &#x2212;50&#xb0; C. to &#x2212;100&#xb0; C. From the low-temperature separation stage, gaseous hydrogen () and methane () are drawn off, while the olefins having at most two carbon atoms are conducted to a further fractionation stage (). The refrigeration power for the low-temperature separation stage is provided by the vaporization via heat exchangers of a portion of the liquid ethylene fraction () resulting in the front end deethanizer. The vaporized ethylene fraction is recirculated to the raw gas compressor ().

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