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…

As is mentioned in the question, it should always be assumed that vent stack fires will occur. The vent stack must be designed to withstand a possible deflagration and the heat from a continuous vent stack fire. The stack should also have sufficient height and be located such that thermal radiation is safe for surrounding personnel, equipment, and buildings. The codes and standards have…

It is not, but the vent stack design outlet is based on radiant heat exposure.

A pressure gauge is not usually provided, as one set of devices (safety valve and rupture disc) is always online by design. If the diverter valve connecting the two sets of relief devices is in the center position, both sets are online although depending upon the design of the diverter valve, it might not allow full flow in either direction. For the secondary stack with a rupture disc and a…

The pressure regulator controls the liquid flow from the tank to the pressure build (PB) vaporizer. As the tank pressure falls, the pressure regulator opens. When the set pressure of the regulator is reached, then the regulator closes. The pressure build circuit depends largely on the required use pressure and the system house-line pressure drop, which is driven by peak flow rate, pressure,…

The most common means to warm liquid or cold gaseous hydrogen is the use of ambient air vaporizers using ambient atmospheric. Other means can be through the use of electric heat or process waste heat.  

Typically, the inner vessel material used is 304 SS and the outer vessel is a combination of 304 SS and carbon steel depending on location. 316 SS or 316L material can be used, but due to higher cost and lower strength, are typically only used for higher purity systems. Nearly all tanks manufactured today use various forms of vacuum jacketed multilayer insulation for best performance. Older…

Catalytic recombiners are effective at preventing flammable hydrogen mixtures and also sometimes useful to monitor hydrogen concentrations through heat evolution when an oxidizer is present. Careful considerations must be made when integrating these elements into a design, so that they do not become a source ignition (and/or flame arrestors prevent propagation of a flame front) and the…

The end use of hydrogen usually drives the cleaning for initial construction. 

1. When the hydrogen is used for combustion and many industrial applications, normal care during construction and leak testing is usually adequate. 
2. When the hydrogen needs to be very pure, as is the case for PEM fuel cell applications, more…

The vent system should be designed for the temperature at which it operates (ambient for GH2 and Cryogenic for LH2). The outlet of the vent system should be designed for a fire to ensure the mechanical integrity of the vent system. 

The supports should also be designed for these temperatures and the associated expansion and contraction. 

It should be ensured that moisture…