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Development of a Solid Catalyst Alkylation Process Using Supercritical Fluid Regeneration
Project Number
FEW4340-68
Goal

The goal was to develop an economical solid catalyst alkylation process via supercritical fluid (SCF) regeneration.

Performer

Idaho National Engineering and Environmental Laboratory (INEEL)
Idaho Falls, ID

Phillips Petroleum Company (ConocoPhillips)
Houston, TX

Background

Alkylation is used by the petroleum refining industry to produce a low-vapor-pressure, high-octane gasoline blendstock. Alkylate is an ultraclean-fuel component and the cleanest gasoline blend stream produced in a refinery. Current industrial alkylation processes catalyze the reaction with concentrated liquid mineral acids, either hydrofluoric (HF) or sulfuric (H2SO4) acids, which pose serious safety and environmental risks. These risks have led Federal and local governments to cease issuing permits for construction of new HF alkylation plants.

Production of this ultraclean fuel is thus at risk and its growth severely limited unless a replacement process can be developed. In order for alkylate to be used as a high-volume, ultraclean fuel, an alternative safe and environmentally acceptable alkylation process is required. Solid acid catalysts could replace liquid acids and eliminate many safety and environmental concerns, but they deactivate rapidly due to deposition and buildup of heavy hydrocarbons on the catalyst surface. Typical catalyst regeneration processes are oxidative and destroy significant levels of acidic alkylation catalyst activity. This results in high levels of catalyst consumption, making solid catalytic alkylation economically and environmentally unacceptable. This project is designed to develop an economical solid catalyst alkylation process via SCF regeneration. Experimental data are to be obtained to determine the maximum number of regenerations, minimum pressure and energy requirements, minimum SCF usage requirements, potential for SCF recycle and reuse, and reactor design requirements for continuous reaction and regeneration.

Alkylation is used by the petroleum refining industry to produce a low-vapor-pressure, high-octane gasoline blendstock. Alkylate is an ultraclean-fuel component and the cleanest gasoline blend stream produced in a refinery. Current industrial alkylation processes catalyze the reaction with concentrated liquid mineral acids, either hydrofluoric (HF) or sulfuric (H2SO4) acids, which pose serious safety and environmental risks. These risks have led Federal and local governments to cease issuing permits for construction of new HF alkylation plants.

Production of this ultraclean fuel is thus at risk and its growth severely limited unless a replacement process can be developed. In order for alkylate to be used as a high-volume, ultraclean fuel, an alternative safe and environmentally acceptable alkylation process is required. Solid acid catalysts could replace liquid acids and eliminate many safety and environmental concerns, but they deactivate rapidly due to deposition and buildup of heavy hydrocarbons on the catalyst surface. Typical catalyst regeneration processes are oxidative and destroy significant levels of acidic alkylation catalyst activity. This results in high levels of catalyst consumption, making solid catalytic alkylation economically and environmentally unacceptable. This project is designed to develop an economical solid catalyst alkylation process via SCF regeneration. Experimental data are to be obtained to determine the maximum number of regenerations, minimum pressure and energy requirements, minimum SCF usage requirements, potential for SCF recycle and reuse, and reactor design requirements for continuous reaction and regeneration.

Impact

This project developed an economical solid catalyst alkylation process via SCF regeneration. Experimental data were obtained to determine the maximum number of regenerations, minimum pressure and energy requirements, minimum SCF usage requirements, potential for SCF recycle and reuse, and reactor design requirements for continuous reaction and regeneration.

Accomplishments (most recent listed first)

During experiments, alkene conversion was maintained above 90% and product quality remained relatively constant during the entire run. Catalyst activity, based on total product yield, was maintained above 90% of its initial level for 132 hours, representing a 15-fold increase in catalyst longevity. These preliminary results are highly encouraging, and it is expected that significant improvements in catalyst life and product yield and quality can be achieved as the process is improved and optimized for commercial feeds.

Current Status

This project is complete.

Project Start
Project End
DOE Contribution

$330,000

Performer Contribution

 $0

Contact Information

NETL - Kathleen Stirling (kathy.stirling@netl.doe.gov or 918/ 699-2008)
INL - Daniel Ginosar (Daniel.Ginosar@inl.gov or 208-526-9049)

Additional Information
Schematic of the automated experimental system for continuous reaction and regeneration.
Schematic of the automated experimental system for continuous reaction and regeneration.
Graph of Butene Conversion
Graph of Butene Conversion
Graph of Activity Recovery
Graph of Activity Recovery

Continuous solid catalyst alkylation reaction/regeneration experiment results showing (top) butene conversion and catalyst activity recovery.