Systems and methods for mixing hydrogen with natural gas

A system for injecting hydrogen into a natural gas pipeline that is connected to an end-use location, the system comprising:

• a hydrogen injection assembly connected to a source of hydrogen and connected to the natural gas pipeline upstream of the end-use location, the hydrogen injection assembly including:
• a hydrogen injection line, and
• a control valve positioned on the hydrogen injection line and connected to the natural gas pipeline thereby to provide an amount of hydrogen at a selected pressure and selected flow rate to the natural gas pipeline;
• a sample assembly connected to the natural gas pipeline downstream of the hydrogen injection line and configured to produce a first output that is indicative of a composition of the blended fuel;
• and
• a controller communicatively connected to the control valve and sample assembly, the controller configured to:
• receive a targeted minimum energy output of a fuel specification for the end-use location;
• determine a blend ratio for a blended fuel comprising hydrogen and natural gas so that the blended fuel (i) has a lower carbon intensity (CI) than a natural gas stream when flowing through the natural gas pipeline, and (ii) provides at least the targeted minimum energy output of the fuel specification when combusted at the end-use location;
• adjust a position of the control valve based at least in part on the blend ratio, thereby to provide the amount of hydrogen into the natural gas pipeline and produce the blended fuel;
• and
• adjust a position of a second control valve positioned along a bypass line connected to the natural gas pipeline based at least in part on the first output, thereby to dilute hydrogen in the blended fuel.

A method for producing a blended fuel comprising hydrogen and natural gas for an end-use location, the method comprising:

• (a) determining one or more energy output requirements for fuel combusted at the end-use location;
• (b) determining one or more characteristics of a natural gas stream in a pipeline connected to the end-use location;
• (c) determining one or more characteristics of a hydrogen stream;
• (d) determining a blend ratio of hydrogen to natural gas for the blended fuel based at least partially on one or more of (i) the one or more energy output requirements, (ii) the one or more characteristics of the natural gas stream, and (iii) the one or more characteristics of the hydrogen stream;
• (e) determining a composition of the blended fuel;
• (f) adjusting a position of a control valve of a hydrogen injection assembly connected to the pipeline based on the blend ratio to mix the hydrogen stream and the natural gas stream in the pipeline, thereby to form the blended fuel;
• and
• (g) in response to a determination that a hydrogen content of the blended fuel is above a target based on the composition of the blended fuel, bypassing a portion of the natural gas stream around the hydrogen injection assembly to dilute the hydrogen content in the blended fuel.

A system for injecting hydrogen into a natural gas pipeline connected to an end-use location, the system comprising:

• a hydrogen injection assembly connected to a source of hydrogen and connected to the natural gas pipeline upstream of the end-use location, the hydrogen injection assembly including:
• a hydrogen injection line connected to the natural gas pipeline at an intersection,
• a control valve positioned on the hydrogen injection line, and
• a bypass line connected to the natural gas pipeline at (i) a first point that is upstream of the intersection and (ii) a second point that is downstream of the intersection;
• and
• a controller communicatively connected to the control valve, the controller configured to adjust a position of the control valve to adjust an amount of hydrogen injected into the natural gas pipeline, thereby to form a blended fuel in the natural gas pipeline based at least in part on one or more of:
• a targeted energy output of a fuel specification of the end-use location;
• a characteristic of a natural gas stream flowing in the natural gas pipeline;
• or
• a characteristic of a hydrogen stream flowing through the hydrogen injection line.