Heterogeneous catalyst engineering ⇒ from stable and deactivation resistant to viable technical catalyst

Problem statement

Advances in heterogeneous catalyst “structure” are driven to improve their “function” or performance, i.e., activity, selectivity, and stability. Cooperative research is required to understand the structure and function relationships: developing new synthesis protocols for heterogeneous catalysts with unique surface properties, defined porosity, identification and understanding of catalytically active sites, reaction mechanisms, and finally, prediction and analysis of the processes using various computational tools.

Our group focuses on developing new catalyst formulations using innovative synthesis routes for various important heterogeneous catalysts. That includes thermal, electro, and bio-electro catalysis.

The active phase cannot be used directly in its final application or reactor for various reasons, including poor mechanical resistance, heat or mass transport, and fluidization features. We must mix the active phase with other ingredients in a matrix of binder and filler, while we shape it into a technical catalyst. We investigate new synthetic protocols for technical catalysis using spray drying and fluidized beds to cover the whole range of sizes. At the same time, we incorporate additional (unconventional) ingredients such as SiC to improve some features even further.

Goals

  • Technical catalyst I ⇒ spray drying and extrusion
  • Technical catalyst II ⇒ spray fluidized bed reactor
  • Technical catalyst III ⇒ electrospinning
  • Zeolite catalysts ⇒ with defined structure/porosity
  • Multi-metal (high entropy) alloy catalysts
  • MXene catalysts ⇒ single and multi-dimensional
  • Perovskite catalysts
  • Metal-organic framework (MOFs) catalysts
  • Supported metal/metal-oxide catalysts
  • Aerogel catalyst

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Related Publications

Effect of the Acidity of the HZSM-5 Zeolite Catalyst on the Cracking of High Density Polyethylene

by Elordi, Olazar, Artetxe, Castaño, Bilbao
Appl. Catal. A: Gen. Year: 2012

Abstract

The catalytic cracking of high density polyethylene (HDPE) has been carried out at 500 °C in a conical spouted bed reactor with two catalysts prepared with HZSM-5 zeolites with SiO2/Al2O3 ratios of 30 and 80. The polyethylene has been fed continuously (1 g min−1) over 10 h to a 30 g catalyst bed. The results show the good performance of the conical spouted bed reactor in minimising the limitations of the physical steps of the process. The deactivation of the catalysts is very low and it is demonstrated that the moderation of the acidity is useful in modifying the product distribution. The SiO2/Al2O3 ratio increment involves a decrease in the total acidity and in the acid strength, resulting in a higher yield of C2–C4 olefins and that of the non-aromatic C5–C11 fraction, and a decrease in the yields of aromatic components and C1–C4 paraffins. The yield of the C2–C4 olefins obtained with the HZSM-5 zeolite catalyst with a ratio of Si/Al2O3 = 80 is 59.8 wt% (that of propylene is 29.6 wt%) and the yield of the gasoline fraction (C5–C11) accounts for 32.1 wt%. The coke deposited on the catalyst has a heterogeneous nature and is constituted by two types of coke, which are deposited on the exterior and the interior of the crystalline channels of the HZSM-5 zeolite. The evolution of the coke is attenuated as the SiO2/Al2O3 ratio of the zeolite is increased.

Keywords

FCC W2C HCE