During EPIC’s Front-End Engineering (FEE) phase, the team reviewed client-provided laboratory data and existing P&IDs to develop an optimized process design. EPIC collaborated closely with the client to refine the distillation configuration and implement necessary adjustments to improve performance and feasibility within the physical constraints of the site.
Advanced Process Modeling and Scale-Up
Distillation modeling played a central role in ensuring process success. Using the client’s lab-scale ternary ethanol mixture data, EPIC evaluated separation behavior across multiple operating conditions, including vapor-liquid equilibrium, reflux performance, and thermal loading.
The modeling confirmed and optimized a two-column separation strategy:
Column 1 (Primary Separation):
- A ternary ethanol mixture is introduced and heated as it descends the column
- Ethanol and water rise and exit as distillate
- Remaining solution is collected at the bottom and circulated through a heat-exchanger loop
- Fresh solvent is pre-heated prior to entry, while reject solvent is cooled and sent to a holding tank
Column 2 (Final Purification):
- Water and ethanol are further separated based on boiling point differences
- Ethanol exits as top distillate and is condensed into a final product stream
- The final output achieves a 91% ethanol concentration
Reflux loops in both columns continuously recycle mixture through multiple separation stages, significantly improving ethanol concentration in the condenser and enhancing overall separation efficiency. Both columns operate under vacuum conditions, reducing boiling temperatures and lowering overall energy demand.
Mechanical Design and Modular Engineering
A critical site visit conducted by EPIC team validated the installation path and confirmed tight spatial constraints. Based on this assessment, EPIC developed a two-part skid design that allowed the system to be split for transport while maintaining full process integration once installed.
Key installation constraints included tight turns, overhead pipe racks, narrow corridors, and minimal clearance between existing tanks and walls. The final design ensured the system could be delivered as two framed sections and reassembled on-site into a single operational unit.
Column diameter, height, piping routing, and equipment placement were engineered simultaneously to satisfy both process performance and installation geometry requirements.
Fabrication, Quality, and Integration
Because the installation area could not safely accommodate extensive field fabrication activities, he complete distillation module was fabricated and assembled off-site in EPIC’s advanced fabrication facility. This approach ensured controlled manufacturing conditions, reduced site disruption, and improved schedule adherence.
To support long-term operational reliability and structural integrity, EPIC incorporated several key engineering recommendations and design enhancements, including:
- A two-column design with five spools to achieve the desired ethanol purity
- Vacuum operation at 4.5 psia to reduce energy consumption during distillation
- Reflux loops on both columns to improve ethanol concentration
- Strategically placed temperature sensors to monitor temperature profiles throughout the columns
- A hot-oil heating system capable of efficiently reaching required operating temperatures near 400°F
- A heat exchanger that recycled thermal energy from outgoing solvent streams to preheat incoming solvent
- Complete hydro-testing to ensure leak-free vacuum operation
- Independent Finite Element Analysis (FEA) verification to confirm skid structural integrity during transportation and installation
