Technology

STAR is the acronym for STeam Active Reforming, a commercially established dehydrogenation technology that was initially developed by Phillips Petroleum Company, Bartlesville, OK, USA. Uhde acquired the technology including process know-how and all patents related to process and catalyst from Phillips in December 1999.^[1]

The STAR process is a cyclic process using Pt-based catalysts supported on alkali promoted Ca and Zn aluminates. It is composed of two stages, loaded with the same catalyst: a reformer, where the dehydrogenation reaction takes place, and an oxyreactor (optional) to shift the equilibrium towards higher olefin yields. In the first stage, reformer-like oxidative dehydrogenation reactors are placed in a furnace, which grants an increasing temperature profile along the reactor bed from 510 to 550–580 °C. Steam is co-fed with propane to convert most of the coke to CO₂, allowing a much long operation time (∼7 h) before regeneration is required (1 h). No addition of sulfur to suppress coke formation, or chlorine to improve catalyst activity via Pt redispersion is needed. Before the second stage, the products are cooled and added with steam to adjust the steam-to-hydrocarbon ratio. In the oxyreactor, oxygen is injected right above the catalyst bed with a patented technology, to selectively combust H₂ and thus shift the thermodynamic equilibrium while providing additional heat for the dehydrogenation reaction. The final product mixture is cooled in a heat exchanger, where heat is supplied to the feed, steam production and downstream separation operations, to improve the overall process efficiency.^[2]

The technology is used to dehydrogenate lower paraffins (propane or butanes) into their corresponding olefins, propylene (Fig. 1) or butylenes (Fig. 2), which can be further processed to valuable downstream products.^[3]

Figure 2: Dehydrogenation of propane to propylene

Figure 3: Dehydrogenation of butanes to butylenes

1. Uhde, uhde_brochures_pdf_en_12, The Uhde STAR process^®, Oxydehydrogenation of light paraffins to olefins

2. M. Monai, M. Gambino, S. Wannakao and B. M. Weckhuysen, Propane to olefins tandem catalysis: a selective route towards light olefins production, Chem. Soc. Rev., 2021, 50, 11503 DOI: 10.1039/D1CS00357G

3. thyssenkrupp Uhde, Dehydrogenation - The STAR process^®, accessed 16^th Jun 2023