XRG designs heaters for highly specialized functions. For example, this heater was designed to achieve uniform heat flux at extremely high coil outlet temperature (1750°F). In addition, the process residence time had to be long enough to accomplish the required conversion to the desired product. The coils are arranged in a way to accommodate coking and reach an acceptable run length between decoking.

Xtend your run length! The unique design of Xtend™ causes the flow to swirl inside the tube, increasing the amount of heat transferred. This generates more swirl with less pressure drop compared to a conventional twisted tape. The swirling flow: Cools the film on the tube wall Removes coke precursors from the film Increases temperature and product uniformity in the tube Xtend™ only needs to be installed in tubes that limit run length due to hot spots; this minimizes pressure drop while maximizing run length and cost savings. Xtend™ is removable. The unique design is sized so that it flexes with build-up and does not engage with coke layer. In coker unit simulations, Xtend™ reduces the tube wall temperature by as much as 33 °F. Lower film temperature and increased bulk flow uniformity result in up to 3x less coking in tubes equipped with Xtend™. Simulations show similar benefits for other services including crude, vacuum, and pyrolysis heaters. If one of these units causes a bottleneck, fixing a few problematic tubes could save millions.

A large crude heater in The Netherlands suffered from reliability, fouling and capacity problems caused by flame impingement. In addition to eliminating this bottleneck, the client wanted to increase heater throughput by 29% and increase fuel efficiency to at least 90%. XRG evaluated the system using CFD and in-house software. The scope involved adding a balanced draft system and new burners in a modified arrangement; installing a new floor, heat exchanger, forced draft (FD) & induced draft (ID) fans; revising the convection section; and providing the new flue gas and combustion air ducting. The existing heater and surroundings were laser scanned and XRG integrated the resulting scans into 3D models, eliminating interferences and ensuring exact fit-up. The outcome was an increase in the thermal efficiency from 78% to 91%, reduced CO2 emissions by 17,685 tons per year, and fuel savings of $1.5 million annually. XRG’s turnkey services included design, material supply, demolition, installation, and start-up support.