ARRANGEMENT FOR REGULATION OF A PLANT FOR THE MEMBRANE PERMEATION TREATMENT OF BIOGAS

Abstract

Arrangement for regulation of a plant I for the membrane permeation treatment of a feed gas stream, comprising at least methane and carbon dioxide, that includes at least one means A for measurement of the gross calorific value (GCV) of the feed gas stream, at least one means B for comparison of the gross calorific value with a setpoint value E, at least one means C for production of a control signal as a function of the comparison of the gross calorific value with the setpoint value E, and at least one means D for transmission of this control signal to a means for regulation of said plant I.

Claims

1. An arrangement for regulation of a plant I for the membrane permeation treatment of a feed gas stream comprising at least methane and carbon dioxide, said arrangement comprising: at least one means A for measurement of the gross calorific value (GCV) of the feed gas stream; at least one means B for comparison of the gross calorific value with a setpoint value E; at least one means C for production of a control signal as a function of the comparison of the gross calorific value with the setpoint value E; and at least one means D for transmission of this control signal, wherein the means D is capable of transmitting the control signal to a means for regulation of said plant I or to a setpoint for concentration of methane or of carbon dioxide at the outlet of the plant in the form of a second setpoint value E′.

2. The arrangement of claim 1, wherein the means B and the means C are combined in a processor.

3. The arrangement of claim 1, wherein the means D for transmission of this control signal is capable of transmitting the control signal to a setpoint for concentration of methane or of carbon dioxide at the outlet of the plant in the form of a second setpoint value E′ and said arrangement comprises: at least one means A′ for measurement of the concentration of methane or of carbon dioxide at the outlet of the plant I, at least one means B′ for comparison of the concentration of methane or of carbon dioxide at the outlet of the plant I with the second setpoint value E′, at least one means C′ for production of a second control signal as a function of the comparison of the concentration of methane or of carbon dioxide at the outlet of the plant I with the second setpoint value E′, at least one means D for transmission of this second control signal to a means for regulation of said plant I.

4. The arrangement of claim 3, wherein the means B and the means C are combined in a first processor and/or the means B′ and the means C′ are combined in a second processor.

5. The arrangement of claim 1, wherein the regulation means comprises a system of valves making it possible to add at least one membrane to or to remove at least one membrane from the plant I.

6. The arrangement of claim 1, wherein the regulation means comprises at least one compressor/backpressure valve assembly making it possible to increase or to reduce the pressure of at least one of the streams employed in the plant I.

7. A process for regulation of a plant I for the membrane permeation treatment of a feed gas stream comprising at least methane and carbon dioxide, said process comprising the steps of: measuring the gross calorific value (GCV) of a feed gas stream; comparing the measured gross calorific value with a setpoint value E; producing a control signal that is a function of said comparison; transmitting the control signal to a means for regulation of said plant I; and regulating the plant I as a function of the transmitted control signal.

8. A process for regulation of a plant I for the membrane permeation treatment of a feed gas stream comprising at least methane and carbon dioxide, comprising the steps of: providing the arrangement of claim 3; measuring the gross calorific value (GCV) of the feed gas stream; comparing the measured gross calorific value of the feed gas stream with a setpoint value E; producing a first control signal for the concentration of methane or of carbon dioxide at an outlet of the plant I as a function of said comparison between the measured calorific value of the feed gas stream and the setpoint value E; transmitting the first control signal to a setpoint for concentration of methane or of carbon dioxide at the outlet of the plant in the form of a second setpoint value E′; measurement a concentration of methane or of carbon dioxide at the outlet of the plant I; comparing the measured concentration of methane or of carbon dioxide at the outlet of the plant I with the second setpoint value E′; producing a second control signal as a function of the comparison between the measured concentration of methane or of carbon dioxide at the outlet of the plant I and the second setpoint value E′; transmitting the second control signal to a means for regulation of said plant I; and regulating the plant I as a function of the transmitted second control signal.

9. The process of claim 7, wherein said regulation comprises adjustment of a number of membranes in the plant.

10. The regulation process of claim 7, wherein said regulation comprises increasing or decreasing a pressure of at least one streams employed in the plant.

11. The regulation process of claim 7, wherein the feed gas stream is biogas.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0065] FIG. 1 is a flow diagram for an embodiment of the process of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0066] The plant can comprise a first membrane separation unit capable of receiving the feed gas stream and of providing a first permeate and a first retentate and a second membrane separation unit capable of receiving the first retentate and of providing a second permeate and a second retentate. In this case, the regulation can, for example, be carried out by an increase or a decrease in the pressure of the feed gas stream and/or of the second permeate. Preferentially, the plant also comprises a third membrane separation unit capable of receiving the first permeate and of producing a third retentate and a third permeate. The plant can optionally comprise a fourth membrane separation unit capable of receiving the third retentate and of producing a fourth retentate and a fourth permeate. It should be noted that the retentates will be enriched in methane and the permeates enriched in carbon dioxide.

[0067] Consequently, in the context of the invention, the term “gas stream employed in the plant” is understood to mean the feed gas stream but also the various permeates and retentates.

[0068] The system of valves making it possible to add at least one membrane to or to remove at least one membrane from the plant makes it possible to add at least one membrane to or to remove at least one membrane from at least one of the membrane separation units of the plant.

[0069] The valves making it possible to add and to remove the membranes of a membrane separation unit are preferably butterfly valves or ball valves.

[0070] The solution according to the invention makes it possible to obtain a stream of methane at the chosen concentration (second retentate).

[0071] This is because to choose a specific content of CO.sub.2 does not guarantee a precise content of CH.sub.4 because other components may be present in the biomethane, such as nitrogen (N.sub.2) or oxygen (O.sub.2). These other components will degrade the calorific value of the biomethane.

[0072] The arrangement according to the invention makes it possible to correct these errors. This is because the gross calorific value takes into account all the constituents of the feed gas stream. Consequently, by basing itself on the latter, the solution according to the invention gives more precise regulation of the membrane plant. The further away the gross calorific value of the feed gas stream is from the gross calorific value of biomethane, the greater the filtration in the membrane permeation plant. And, conversely, the closer the gross calorific value of the feed gas stream is to the gross calorific value of biomethane, the lower the filtration in the membrane permeation plant.

[0073] 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 single step.

[0074] The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.

[0075] “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”.

[0076] “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.

[0077] 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.

[0078] 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.

[0079] 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.