At its 52,000 bpd refinery in Cheyenne, Wyo., HollyFrontier is installating a 10-MMscfd hydrogen plant to replace the refinery’s inefficient 4-MMscfd existing plant. It is on schedule for completion during the fourth quarter of 2015.
The $34-million hydrogen plant project, along with a recently completed naphtha fractionation project, is designed to help reduce benzene content in gasoline production while simultaneously improving overall liquid yields and light oils production at the refinery.
Additional projects still under way at Cheyenne include wastewater treatment plant improvements, a flue-gas scrubber for the FCC to reduce air emissions, and a redundant tail-gas unit associated with the sulfur recovery process.
HollyFrontier also is considering an $8.6-million FCC liquid-yield improvement project at Cheyenne with expected completion in spring 2016.
Alkylation is one of the conversion processes used in petroleum refineries. It creates additives that boost the octane of gasoline by converting isobutanes into an alkylate.The process occurs in the presence of a strong acid, acting as a catalyst. In many cases, the acid used is Hydrogen Fluoride (HF). The Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) regulate HF as highly toxic. If released in the atmosphere, HF rapidly forms dense vapor clouds that hover near land and can travel great distances. Like other powerful acids, HF can cause deep severe burns and damage the eyes, skin, nose, throat and respiratory system.
As a result of the hazards associated with HF , HollyFrontier was seeking a solution to provide the maximum protection with the highest availability and no maintenance for its Cheyenne Refinery located in Wyoming. HollyFrontier worked with Senscient’s distributor, Relevant Solutions, to evaluate the Senscient technology. The solution provided by Relevant is a system composed of four individual Senscient open-path HF gas detection sensors, creating a full detection perimeter around the Alkylation Unit process area.
It was determined that using the ELDSTM open path system is the best solution to provide all the safety criteria required by the refinery plus additional benefits. These benefits included;