Micro Downflow Technology

Test catalysts and feeds for Fluid Catalytic Cracking (FCC) under relevant process conditions but with laboratory scale budgets

The micro downflow unit (MDU) is based on a lab-scale technology and offers an entrained catalyst flow reactor system analogous to commercial fluid catalyst cracking units (FCCUs). It can be operated within a wide range of process conditions, including elevated pressures which are typical for FCCUs. Furthermore, the MDU is fully automated and cost-efficient as only small amounts of catalysts and feeds are required. Processability of a broad range of feedstocks has been demonstrated, ranging from naphtha and vacuum gas oil to residue feeds and crude oils. It includes the latest software solution myhte™ for integrating, storing, retrieving, analyzing, and visualizing data.

Features of Micro Downflow Unit (MDU)

  • Entrained flow reactor as commercial FCCU
  • Pressures typical for an FCCU or a riser can be adjusted
  • Since catalyst and feed move in the direction of gravity back-mixing is low
  • Size, required material amounts, and operating expenditures in the range of laboratory methods
  • Experiments at catalyst reactor residence times / contact times comparable to riser reactors
  • Capability of simulating high severity operations (high cat-to-oil ratio) 
  • Cost-efficient (operation, catalyst, feedstock)
  • Fully automated lab system
  • 5 crackings per 8 hour shift w/ optional increase to 18 crackings per day
  • Mass balances 98 +/- 2 %
  • Reproducible results matching well with circulating riser units and commercial FCCUs
  • Flexible and broad parameter range
  • Variety of feedstocks possible: VGO, high resid VGO, light cut naphtha, pyrolysis oils, biogenic feeds and full crude oil
  • Feedstocks with CRC’s 0-10 % can be processed

Reactor set-up of the MDU

Typical process parameters

Operating pressure0.2 - 3.5 barg
Reactor temperatureup to 700 °C
Catalyst inlet temperatureup to 750 °C
Oil pre-heat  up to 250 °C
Oil feed rate3 - 12 g/min
Cat-to-oil ratio 3 - 50
Experiment duration1 min (can be adjusted)

Comparison of yields vs. conversion for ACE-CRU-MDU

MDU infrastructure requirements


  • Typical footprint 1.5 m x 3.5 m x 1.2 m (WxHxD) plus room for GC and PC workplace (height depending on the length of the reactor)
  • Only local fume hood exhaust necessary


  • N2: 10 barg/100 barg
  • Synthetic air: 10 barg
  • House air: 10 barg
  • GC gases: H2, He, N2, Ar


  • 400 VAC/5kW, other voltages upon request

Appearance and footprint of the downflow unit delivered may differ from the unit displayed. 

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