Apparatus and process for removal of heavy hydrocarbons from a feed gas
AssigneeHoneywell Lng LLC
InventorMark Julian Roberts
Life of this patent
Estimating the term…
Abstract
An apparatus and process for removal of heavy hydrocarbons (e.g., hydrocarbons that include five or more carbons such as pentane and hexane, etc.) from a feed (e.g., a feed comprised of methane and impurities) can include a scrub column and a stabilizer column arranged so that a portion of a first stream output from the stabilizer column is fed to the scrubber column to function as a reflux stream. Embodiments are provided in which the scrub column produces a stream comprising mostly methane (e.g. over 85 mole percent methane) and reduced heavy hydrocarbons so that reduced operational costs and improved operational flexibility can be realized in downstream natural gas liquefaction operations.
Claims16
An apparatus for removal of heavy hydrocarbon impurities from a feed comprising methane gas and hydrocarbons having at least five carbon atoms, the apparatus comprising:
- a scrub column positioned and configured to receive the feed and output a first scrub column stream and a second scrub column stream, the second scrub column stream comprising the hydrocarbons having at least five carbon atoms,
- a stabilizer column positioned downstream of the scrub column to receive the second scrub column stream and configured to output a first stabilizer column stream and a second stabilizer column stream, the second stabilizer column stream comprising the hydrocarbons having at least five carbon atoms,
- a phase separator positioned to receive the first stabilizer column stream and output a vapor stream and a liquid stream, and
- a heat exchanger positioned to receive the vapor stream from the phase separator and a first portion of the liquid stream from the phase separator;
- wherein the scrub column is positioned such that a portion of the first stabilizer column stream is fed to the scrub column as a scrub column reflux stream;
- wherein the portion of the first stabilizer column stream that is fed to the scrub column as the scrub column reflux stream comprises the vapor stream from the phase separator and the first portion of the liquid stream from the phase separator;
- wherein the heat exchanger is configured and positioned to cool a first portion of the feed before the feed is fed to the scrub column;
- wherein the scrub column is positioned so that a third portion of the feed is passed through a side reboiler of the scrub column to cool that portion of the feed;
- and
- wherein the heat exchanger and the scrub column are positioned such that the third portion of the feed cooled in the side reboiler is combined with the first portion of the feed and fed to the scrub column.
A process for treating a feed gas comprising methane and hydrocarbons having at least five carbon atoms, the process comprising:
- providing the feed gas to a scrub column operating at a pre-selected scrub column operational pressure range to output a first scrub column stream and a second scrub column stream from the scrub column, the second scrub column stream comprising the hydrocarbons having at least five carbon atoms;
- feeding the second scrub column stream to a stabilizer column operating at a pre-selected stabilizer column operational pressure range to output a first stabilizer column stream and a second stabilizer column stream, the second stabilizer column stream comprising the hydrocarbons having at least five carbon atoms;
- providing a portion of the first stabilizer column stream to the scrub column to provide a scrub column reflux stream to the scrub column;
- splitting the feed into a first portion, a second portion, and a third portion, feeding the first portion to a heat exchanger positioned upstream of the scrub column, mixing the first portion exiting the heat exchanger with the second portion before providing a stream comprising the first and second portions to the scrub column;
- and
- feeding the third portion to a side reboiler to form a stripping vapor, and feeding the stripping vapor to the scrub column,
- wherein the process comprises mixing the third portion with
- the second portion and the first portion before the first portion, second portion, and third portion of the feed are fed to the scrub column,
- the second portion before the first portion, second portion, and third portion of the feed are fed to the scrub column, or
- the first portion before the first portion, second portion, and third portion of the feed are fed to the scrub column.
Dependencies are inferred from the claim text.