Patent DE-102010051805-A1 (DE)
Title: Recovering hydrocarbons from hydrocarbon-containing feed gas, comprises cooling and separating feed gas, supplying gaseous fraction of feed gas into the mass transfer columns and preventing passage of liquid phases
Inventor: PFEIFFER CHRISTIAN
IPC: C07C7/00
Filed: 2010-11-18
Abstract: Recovering hydrocarbons from a hydrocarbon-containing feed gas (1), comprises: (a) cooling the feed gas; (b) separating the feed gas into a gaseous fraction and a liquid fraction (18); (c) supplying the gaseous fraction and the liquid fraction to a mass transfer column; (d1) supplying the gaseous fraction of the feed gas into the 2C-mode of the mass transfer column; (d2) supplying the gaseous fraction of the feed gas into the 3C-mode of the mass transfer column in the absorption section; and (e) preventing passage of liquid phases to be vaporized through the same passages of the evaporator. Recovering hydrocarbons from a hydrocarbon-containing feed gas (1), where the feed gas is separated into a gas product fraction and a liquid product fraction, the hydrocarbon-containing feed gas contains methane, hydrocarbons having 2 carbon atoms, hydrocarbons with three carbon atoms and heavier hydrocarbons and trace elements, and the liquid product fraction contains the major portion of the hydrocarbons with 2 carbon atoms, hydrocarbons with 3 carbon atoms and heavier hydrocarbons or the major portion of hydrocarbons with 3 carbon atoms and the heavier hydrocarbons of the feed gas, and the two different variants of the method are referred to as 2C-mode and 3C-mode, comprises: (a) cooling the feed gas by at least one heat exchanging step with the gas product fraction; (b) separating the feed gas at least after a heat exchanging step by a separator into a gaseous fraction and a liquid fraction (18); (c) supplying the gaseous fraction and the liquid fraction to a mass transfer column, which is operated in the 2C-mode as demethanizer and in 3C-mode is as deethanizer, and the mass transfer column is divided into 2 different sections, where the upper column section is operated as the absorption section and the lower column section is operated as a stripping section; (d1) supplying the gaseous fraction of the feed gas and a portion of the gas product fraction and the stripping section of the liquid fraction of the feed gas and at least one gaseous fraction into the 2C-mode of the mass transfer column in the absorption section, which forms at least one intermediate bottom of the stripping section by evaporation in at least one evaporator by heat exchange with parts of the feed gas, and the gaseous fraction of the separator; (d2) supplying the gaseous fraction of the feed gas and a portion of the gas product fraction and the stripping section of at least one gaseous fraction into the 3C-mode of the mass transfer column in the absorption section, which forms the liquid fractions of the separator by evaporation in the same evaporator as in the 2C-mode by heat exchange with parts of the feed gas and the gaseous fractions of the separator, and The mass transfer column and the evaporator can be changed by switching of control valves between 2C-mode and 3C-mode with the consequent use of feed streams; and (e) preventing passage of the liquid phases to be vaporized through the same passages of the evaporator in the 2C-mode and 3C-mode.