Project Overview

One of the process units at the Client’s site was prone to occasional gas compressor trips. These events left residual light hydrocarbons in the reactors – a potential hazard upon restart. As a safeguard, the Client wanted the ability to sweep the reactors with make-up hydrogen while the catalyst was still hot. Rally engineered a jump-over line between two pipe headers that allowed the operators to quickly redirect make-up hydrogen into the reactors after future compressor trips.

Install Hydrogen Jumpover Line main Install Hydrogen Jumpover Line first

Scope Definition

Rally met with the plant operators and project leads in the unit to walk down the scope of work and identify potential tie points. Special emphasis was placed on ensuring that the new jump-over valves would be quickly accessible from existing platforms in the event of a compressor trip.
At the Client’s request, the installation of new flanges was kept to an absolute minimum. This eliminated potential hydrogen leak-points.
Low-temperature carbon steel materials were used for the new piping, acknowledging that the uninsulated jump-over line could be pressed into service without a warm-up at any time of the year.


Rally provided detailed engineering services, culminating in a multi-discipline construction work package (CWP). It included details for making piping tie-ins during the next unit outage, constructing the hydrogen jump-over line between the tie-ins, and adding structural steel pipe supports.
Rally revised the plant piping & instrumentation diagrams (P&IDs) and facilitated a process hazard analysis (PHA). This ensured that any new risks of misdirected flow were understood and safely mitigated.

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