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Storage, System Design

Category

Storage, System Design
Are there codes or standards addressing the installation of a hydrogen flare system for excess hydrogen production. Some API and NASA documents address flaring, but flaring is not covered within NFPA 2 and NFPA 55.

Refineries and large petrochemical plants will frequently have flare systems for H2 and other flammable materials. One of the major purposes of these flare systems is to prevent a large unignited cloud from forming since that could result in an explosion hazard and large deflagration overpressures if there is a delayed ignition. However, these are in large facilities which have the…

Category: System Design
Keywords: Venting, Flaring, Ignition
Are there specific hazards to consider when mixing varied H2 temperature streams (gas and liquid) at a pipe junction, considering the following design features? (1) Cold hydrogen at the pump discharge is directed along two paths. One path uses ambient heat to warm the hydrogen, while the other path bypasses the heater to remain cold. Valves in each stream then adjust the flow split to achieve a controlled hydrogen mix temperature when the streams are recombined. The temperature-controlled stream is then directed to a dispensing station. (2) The hydrogen chilling system combines the cold hydrogen fluid with warmer hydrogen compressed gas to achieve the temperature necessary to provide a fast-fueling experience. The system will monitor the chilled fluid temperature and the vaporized warm gas and combine their streams using mixing valves and controls to provide -40 deg C° gas to the dispensers.

This is a fairly common arrangement and can be acceptable if properly designed. Some considerations:

  1. The main concern is low temperature downstream of the mixing point, in case of mixing valve failure. Perform a LOPA (layer of protection analysis) on the safeguards. A shutdown table showing the action of each shutdown would help with understanding the layers of protection. The…
Category: System Design
Keywords: Fueling Station, Mixing, Temperature
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This material was prepared as an account of work sponsored by an agency of the United States Government.
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The portal brings together and enhances the utility of a variety of tools and web-based content on the safety aspects of hydrogen and fuel cell technologies to help inform those tasked with designing, approving or using systems and facilities, as well as those responding to incidents.

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