Selective Hydrogenation Unit Skid

It is well known that a selective hydrogenation unit (SHU) can improve the operational economics of an alky unit by eliminating butadiene in the feed and (optionally) converting butene-1 to butene-2.  The result is reduced acid consumption, increased gasoline production, and (for HF units,) increased alkylate octane.

Vanguard Catalyst, LLC has taken a fresh approach to mature technology borrowing the best of catalysis and reaction engineering from refining and petrochemicals.  High activity catalysts minimize reactor volume.  Hydrogen scavenger eliminates the product stripper.  Modular, skid construction provides a low cost, turnkey solution.

For more information about SHU catalysts, click here.

Reduced Acid Consumption

The primary purpose of a selective hydrogenation unit is the elimination of 1,3 butadiene via hydrogenation.  Reduced butadiene in the feed improves the operation of the alkylation unit via:

  • Reduced cost of acid replacement or regeneration
  • Reduced acid transportation
  • Reduced production of acid soluble oils

Each barrel of butadiene removed reduces consumption of (a) H2SO4 by 0.8 ton, or (b) HF by 17 lb.

Increased Gasoline Production

Butadiene is converted to butylene and butane in the SHU.  The additional butylene, along with isobutane, becomes alkylate.  Butane is a blend component.  Each barrel of butadiene converted plus 0.8 barrels isobutane equals 1.1 additional barrels of alkylate and 0.3 barrels of normal butane.

Increased Alkylate Octane

Hydrofluoric acid alkylation units (but not sulfuric acid) produce higher octane alkylate from butene-2 compared to butene-1.

Palladium catalyst will convert butene-1 to butene-2 via hydroisomerization after butadiene removal.  The octane rating of the alkylate produced by the typical C4 stream typically goes up by 1.0 after BD and butene-1 conversion.

SHU Skid CAD diagram
SHU SkidSHU Process Diagram

 Reduced Capital Cost

The capital cost of the SHU is reduced compared to a conventional approach:

  • Eliminate light ends stripper by eliminating excess hydrogen via saturation.
  • Modular/skid construction reduces costs and construction delays.
  • Multiple standardized modular vessels are lower cost than large, custom-designed vessels.
  • Modular reactors allow simple, fast catalyst replacement so that less installed catalyst volume is required.

Typical ISBL savings are between 40% and 70% as compared to a conventional approach.

Short Payback Project

The primary benefit of a SHU unit is acid savings for sulfuric acid alkylation units and octane gain for hydrofluoric acid alkylation units.  Other benefits and costs are secondary.

The primary project cost is the SHU skid.  However, the cost of tie-ins and other owner costs can equal this amount.

The typical payback for a SHU skid project is between one and two years for hydrofluoric acid alkylation units and between two and three years for sulfuric acid alkylation units.

Contact Us

If you are interested in our SHU Skid or Vanguard hydrogenation catalysts, please contact us today.  If you know your process details, please fill out our questionnaire, downloadable by clicking the icon below.