Patent ID: 12246295

DETAILED DESCRIPTION OF THE INVENTION

Part of a system for introducing gas from an unconventional source into a grid gas pipeline according to the present invention is shown inFIG.2. The system comprises a passive blender10, a first gas input pipe11from a grid gas pipeline2into the passive blender10, a second gas input pipe3from an unconventional source1into the passive blender10, and an output pipe12from the passive blender10to the grid gas pipeline2. The system further comprises a compressor or regulator25, a liquid petroleum gas (LPG) injection apparatus5, a gas cleaner4, and an analyser13. The pipe3transports gas from the unconventional source1into the grid gas pipeline2. The analyser13communicates with the injection apparatus by means of a feedback signal24. The system ofFIG.2operates in the following manner.

Gas from the grid gas pipeline2is fed into the passive blender10via the first gas input pipe11. This input is at the pressure ‘p’ of the grid gas pipeline2. Gas from the unconventional source1is fed into the passive blender10via the second gas input pipe3. This input is at a pressure ‘P’. Pressure ‘P is greater than pressure ‘p’. The precise composition of the gas output with regards to proportion of gas from the grid gas pipeline and gas from the unconventional source can be controlled by design of the passive blender10and/or the size of the first and second gas input pipes11,3and/or controlling the flow of the gas in the second gas input pipe3.

Gas from the unconventional source1is conditioned and compressed and/or regulated in the manner according to the prior art. This may include using LPG from the LPG injection apparatus5. The gas is then fed into the passive blender10and mixed with gas from the grid gas pipeline2. The gas then outputs the passive blender10through the output pipe12, passes through a sample point connected to the analyser13, and is passed into the grid gas pipeline2downstream of where the first input pipe11takes gas from the grid gas pipeline2. Should the grid pipeline gas reverse direction of flow, the passive blender system continues to operate safely but less efficiently. The analyser13analyses gas passing through the output pipe12and when it is determined that the gas in the output pipe12is not suitable for entry into the grid gas pipeline2this is communicated to the injection apparatus5and LPG injection will begin or be increased to until the gas in the output pipe12is of an acceptable quality for injection into the grid gas pipeline2.

As the gas from the unconventional source1is mixed with gas from the grid gas pipeline2in the passive blender10before being introduced into the grid gas pipeline the gas can require less conditioning. In particular, the amount of LPG that is required to be mixed with the gas may be reduced or eliminated. This is because previously it was necessary for the conditioned gas from the unconventional source1to be suitable for entering the grid gas pipeline2, whereas in the system of the present invention all that is required is that conditioned gas from the unconventional source1is suitable for entering the grid gas pipeline2after it has been mixed with a significant proportion of gas from the grid gas pipeline.

The analyser13is provided after the passive blender10. This provides control of the LPG injection, by means of a signal (24), based on characteristics and properties measured and/or calculated from samples of the blended gas analysed in the analyser13.

A cross-section of a first embodiment of a passive blender10forming part of a system according to the present invention is shown inFIG.3. The passive blender10substantially comprises a swept tee joint14formed of a suitable material. The first input pipe11from the grid gas pipeline2is attached to a side of the passive blender10. The second input pipe3from the unconventional source is attached to a first end of the passive blender10. The output pipe12from the passive blender is attached to a second end of the passive blender10. The gas from the unconventional source1is at pressure ‘P’. The gas from the grid gas pipeline2is at the same pressure ‘p’ as the gas in the grid gas pipeline, p being lower than P. Although not accurately depicted in the Figure, where they enter the passive blender the second input pipe3is smaller in diameter than the first input pipe10and the output pipe12. In this manner the gas from the unconventional source1,3entrains gas from the grid gas pipeline2,11into its flow and the two are blended together for output through the output pipe12.

A cross-section of a second embodiment of a passive blender10′ that may comprise part of a system according present invention is shown inFIG.4. This passive blender10′ is cylindrically symmetrical and comprises an input section21wherein gas from the grid gas pipeline2enters the passive blender, this section narrows in diameter along a direction in which the gas flows. Gas from the unconventional source1is input into the passive blender10′ at the end of the input section21. The input22from the unconventional source1is substantially annular at input pipe3and surrounds the end part of the input section such that the gas from the unconventional source1is introduced around the gas from the grid gas pipeline11at the narrowest point of the passive blender10′. After the end of the input section21is an output section23in which the diameter of the passive blender10′ gradually increases in diameter. The gas from the unconventional source1is at pressure ‘P’. The gas from the grid gas pipeline2enters the passive blender10′ from input pipe11at the same pressure ‘p’ as the gas in the grid gas pipeline, p being lower than P.

The decrease in diameter of the passive blender10′ in the input section21followed by the increase in diameter of the passive blender in the output section23result in the passive blender10′ and the increased velocity and direction of the gas from input3using an inspiration effect to entrain and mix the gas from the grid gas pipeline2with the gas from the unconventional source1.

A third embodiment of a passive blender10″ that may form part of a system according to the present invention is shown inFIG.5. The third embodiment10″ is similar to the second embodiment in that it comprises an input section21in which the diameter of the passive blender10″ reduces and an output section23in which the diameter of the passive blender10″ increases. However, the gas from the unconventional source1is injected substantially centrally into the flow of gas from the grid gas pipeline2by means of a substantially central injector pipe3that has an outer end positioned within the input section21of the passive blender10″. The gas from the unconventional source1is at pressure ‘P’. The gas from the grid gas pipeline2enters the passive blender10″ from input22and at the same pressure ‘p’ as the gas in the grid gas pipeline, p being lower than P.

In the same manner as the second embodiment of the passive blender10′ the decrease in diameter of the passive blender10′ in the input section21followed by the increase in diameter of the passive blender in the output section23result in the passive blender10′ and the increased velocity and direction of the gas from input3using the inspiration effect to entrain and mix the gas from the grid gas pipeline2with the gas from the unconventional source1.

A fourth embodiment of a passive blender that may form part of a system according to the present invention is shown inFIG.6. This passive blender10″′ comprises an input section21wherein gas from the grid gas pipeline2enters the passive blender, this section narrows in diameter along a direction in which the gas flows. The passive blender10″′ has a central section of relatively small diameter between an end of the input section21and a start of an output section23. In the output section23the diameter of the passive blender10″′ gradually increases in diameter. Gas from the unconventional source1is input into the passive blender10′ in the central section. In particular, an input22from the unconventional source1,3is substantially annular and surrounds the central section such that the gas from the unconventional source1is introduced around the gas from the grid gas pipeline2,11substantially at a mid-point of the central section. The gas from the unconventional source1is at pressure ‘P’. The gas from the grid gas pipeline2enters the passive blender10′ from pipe11at the same pressure ‘p’ as the gas in the grid gas pipeline, p being lower than P.

The decrease in diameter of the passive blender10′ in the input section21, followed by the central section of relatively low diameter, followed by the increase in diameter of the passive blender in the output section23result in the passive blender10′ and the increased velocity and direction of the gas from input3using an inspiration effect to entrain and mix the gas from the grid gas pipeline2with the gas from the unconventional source1.

Any of the passive blenders ofFIGS.3to6may be used in the system ofFIG.2. In any such system a compressor25or other similar apparatus may be used to increase the pressure of the unconventional gas before it enters the passive blender10,10′ or10″.