FACILITY FOR THE TREATMENT OF A STREAM OF METHANE AND CARBON DIOXIDE BY MEANS OF A VANE-TYPE COMPRESSOR AND OF A MEMBRANE SEPARATION UNIT

Abstract

Facility for the treatment of a feed gas stream comprising at least methane and carbon dioxide, said facility comprising: an oil-lubricated or water-lubricated vane-type compressor making it possible to compress the feed gas stream, and a membrane separation unit capable of receiving the compressed gas stream and of separating the methane from the carbon dioxide.

Claims

1. A facility for the treatment of a feed gas stream comprising at least methane and carbon dioxide, said facility comprising: an oil-lubricated or water-lubricated vane-type compressor adapted and configured to compress the feed gas stream; and a membrane separation unit in fluid communication with the compressor that is adapted and configured to receive the compressed gas stream and separate the methane from the carbon dioxide therein.

2. The facility of claim 1, further comprising: at least a pressure sensor adapted and configured to measure a pressure of the feed gas stream at an inlet of the membrane separation unit; and a controller that is adapted and configured to compare a pressure measured by the at least a pressure sensor with a target value, and adjust compression of the feed gas stream within the vane-type compressor.

3. The facility of claim 1, wherein the lubricated vane-type compressor is adapted and configured to increase the pressure of the feed gas stream to a pressure between 6 and 13 barg.

4. The facility of claim 1, wherein the membrane separation unit comprises: a first membrane separation subunit adapted and configured to receive the gas stream leaving the adsorbers and to produce a first carbon dioxide-enriched permeate and a first methane-enriched retentate; a second membrane separation subunit adapted and configured to receive the first retentate and to produce a second carbon dioxide-enriched permeate and a second methane-enriched retentate; and a third membrane separation subunit adapted and configured to receive the first permeate and to produce a third methane-enriched retentate and a third CO.sub.2-enriched permeate.

5. A process for treating a feed gas stream comprising at least methane and carbon dioxide in order to produce a methane-enriched gas stream, using a facility of claim 1, comprising the steps of: a) compressing the feed gas stream to a pressure of between 6 and 13 barg by means of the oil-lubricated or water-lubricated vane-type compressor; b) eliminating and filtering, from the compressed feed gas stream, one or more of impurities, water vapor, and oil vapor; c) separating, in the membrane separation unit, the carbon dioxide and methane in the compressed feed gas stream from which one or more of impurities, water vapor, and oil vapor have been eliminated and filtered; d) measuring a pressure of the feed gas stream at the inlet of the membrane separation unit; and e) comparing the measurement taken in step d) with a target value, and in the event of a difference between the measurement taken and the target value, modifying the compression of the feed gas stream within the compressor.

6. The process of claim 5, wherein step e) is carried out automatically by a data transmission and data processing means.

7. The process of claim 5, wherein steps a) to e) are carried out continuously.

8. The process of claim 5, wherein the feed gas stream is biogas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0027] A subject of the present invention is also a process for treating a feed gas stream comprising at least methane and carbon dioxide in order to produce a methane-enriched gas stream, using a facility according to the invention and comprising: [0028] a) a step of compressing the feed gas stream to a pressure of between 6 and 13 barg by means of the oil-lubricated or water-lubricated vane-type compressor, [0029] b) a step of eliminating and filtering the impurities and the water vapours or oil vapours, [0030] c) a step of separating the carbon dioxide and methane in the membrane separation unit, [0031] d) a step of measuring the pressure of the feed gas stream at the inlet of the membrane separation unit, [0032] e) a step of comparing the measurement taken in step c) with a target value, and [0033] f) in the event of a difference between the measurement taken and the target value, a step of modifying the compression of the feed gas stream within the vane-type compressor.
Depending on the case, the process according to the invention can exhibit one or more of the following features: [0034] steps d), e) and f) are carried out automatically by data transmission and data processing means, the data transmission and data processing means being a controller, such as a programmable logic controller or computer; [0035] steps a) to f) are carried out continuously; [0036] the feed gas stream is biogas.

[0037] While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a simile step.

[0038] The singular forms a, an and the include plural referents, unless the context clearly dictates otherwise.

[0039] Comprising in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing i.e. anything else may be additionally included and remain within the scope of comprising. Comprising is defined herein as necessarily encompassing the more limited transitional terms consisting essentially of and consisting of; comprising may therefore be replaced by consisting essentially of or consisting of and remain within the expressly defined scope of comprising.

[0040] Providing in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.

[0041] Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.

[0042] Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.

[0043] All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.