Perspectives: Making it Work

Innovative Design Tackles Tight Plant Footprint

Dual distillation column approach enables installation of new ethanol extraction technology

By Art Goldmann, EPIC Modular Process Systems

A facility in Illinois wanted to test the viability of a new ethanol extraction technology. However, this would require building a distillation column in a location virtually impossible to reach. Moreover, the unit would have to fit within a tight footprint and its installation would involve intricate rigging. Yet the facility couldn’t be altered to accommodate the new process system. The distillation unit was an add-in to a larger project, and the rest of the facility layout already had been completed. In addition, because of ongoing operations, constructing the system onsite wasn’t an option. To further complicate matters, the installation path involved multiple doorways with fixed dimensions, overhead piping and conduits, and several 90° turns.

“The pre-design site visit was critical. There was no way we could have developed the proper skid design or the detailed rigging plan without that visit. Those measurements were critical, and the path was very tight. The final resting place for the skid was in a very small space along the back wall of the plant. The client knew they needed the distillation system, but they had no idea how to get the system to the final destination,” says Ken Sipes, manager of EPIC’s Process and Mechanical Group. “We knew a modular solution was the answer, but actually getting the skid into the plant meant we couldn’t design the system as one big skid. We had to get creative.”

In response to this problem, the EPIC team devised a two-skids-in-one design. This involved engineering and manufacturing two self-contained units that, when fully installed, would work as one seamless unit (Figure 1). System scale-up with HYSYS software and 3D CAD design were developed around this idea, using lab-scale data and process-and-instrumentation drawings from the client. Finite element analysis performed by an independent source confirmed that each skid would bear the stress of navigating a complicated installation path.

DESIGN OF THE TWO SKIDS
Column diameter and height, piping locations and equipment placement were carefully chosen to fit within the two skids. The final design includes two distillation columns, each comprised of five spools. Both columns are rated for 15 psig at 250°F and feature reflux loops to achieve higher ethanol extraction rates. A vacuum pump lowers required energy inputs for distillation within both columns. Special attention was paid to the process flow, to determine equipment placement in the two separate sections.

The first column receives a three-component feed stream. Water and ethanol come off the top of the column while solvent remains as the bottoms product. To conserve energy, solvent leaving the bottom of the column goes through a heat-exchanger loop to preheat the incoming feed. The rejected solvent then is pumped to an off-skid holding tank. Meanwhile, water and ethanol enter the second column where ethanol is recovered as the overhead product. A condenser located on the second skid condenses the ethanol, which goes to an off-skid holding tank.

Piping design was critical. Minimizing overall piping requirements to control project costs was a general goal. The process piping requirements had to be balanced with the piping necessary to connect the process across the two skids. As few connections as possible were desired to reduce potential problems in the handoff between the two skids. The connections between skids were assembled and hydro-tested at EPIC’s fabrication facility before being disconnected temporarily for the journey to the installation site.

SUCCESS
The project was delivered on time and on budget due to the innovative modular design. Following a carefully developed rigging plan, the system was transported and installed successfully at the client site. The overall project timeline was shortened because the skids were built at EPIC’s fabrication facility (Figure 2) while the large plant-upgrade project continued at the client site.

Installation and startup only took a few days because the “plug-and-play” system was fully tested before shipment. Once onsite in the final operational location, process connections and inter-skid connections were mated together and the system was brought online. The distillation unit is performing as planned, providing 91% ethanol extraction.

The entire project took four and half months from the first inquiry by the client to startup at the facility. Engineering, design and drawings accounted for eight weeks; fabrication and assembly consumed eight weeks; testing at EPIC’s shop took one week; delivery and installation required one week; and an on-site EPIC automation engineer provided training for one week.



ART GOLDMANN, P.E., is a senior project manager and process engineer for EPIC Modular Process Systems, St. Louis, Mo. E-mail him at agoldmann@epicsysinc.com.

More from this perspective...

Title

Key Steps Spur More-Effective Root Cause Analyses

An Axiall plant has taken steps to root out RCA inconsistencies.

01/14/2014

Low flow injection improves scale-up of catalysts

Dow Chemical recently developed a reactive catalyst for use in one of its production facilities. Indications were that this new catalyst could save the company millions of euros once it reached full-scale production. The challenge was transferring the recipe using this new reactive catalyst from the laboratory to the pilot plant and, ultimately, to the production level.

08/07/2006

Low-Cost Monitoring Protects Pricey Pump

Wireless pH analyzer provides crucial insights on seal integrity.

08/13/2012

Lower-Cost Route to Acrylic Acid Nears

Abundant supplies of shale gas lead to significant savings.

02/05/2014

Membrane Boasts Material Benefits

As economical separation of contaminants from natural gas becomes increasingly important, simulation eases the design of innovative module to remove carbon dioxide. Membranes offer potential advantages over other methods.

09/11/2007

Mixer Seal Gets Major Makeover

Novel retrofit prevents leaks and offers other benefits.

06/02/2011

Modeling Speeds Capacity Expansion

Simulation allows evaluation of more options more quickly.

02/02/2012

Multi-Facility Approach Provides Clarity

Linking automation KPIs to business value identifies priorities for action.

08/13/2011

Neville Chemical upgrades efficiency and safety

A self-cleaning filter not only allowed one company to add efficiency and safety, it also boosted competitiveness.

01/03/2006

New Flow Meter Boosts Solvent Recovery and Much More

Improved measurement accuracy delivers better control and savings.

09/09/2010

Non-invasive Wireless Monitoring Provides Fast Payback

Use on steam traps and research freezers leads to energy savings and improved uptime.

05/31/2009

Nonlinear Models Enhance Distillation

Production-data-based approach leads to improved efficiency of rosin column.

10/04/2011

Oil refinery minimizes manual tank measurements

The strategy was to enhance plant profitability, increase throughput capacity, upgrade product yields and improve on-stream reliability. Read here to find out what they accomplished.

02/10/2006

Online Analytics Improves Batch Operations

Field trial shows value for fault detection and quality prediction.

03/29/2011

Outsourcing innovation development

A new development method may allow breaking away from the pack as companies continue to employ outsource facilities that offer flexibility and foster innovation.

10/31/2006

Oxygen Boosts Performance of Wastewater Treatment Plant

Opting for innovative system enables capacity expansion at Korean site.

08/20/2013

Particles From Piping Pose Pump Problems

Magnetic separators remove black powder to improve performance.

02/08/2010

Petrochemical Complex Ramps up Reliability

Multipronged initiative leads to substantially improved asset performance.

10/03/2013

pH sensor stands up to tough conditions

Design provides improved reliability in a polymer-precursor batch reactor. Sensors must respond quickly and survive a harsh environment. Poor probe reliability can make the difference between a process that makes money and one that doesn’t.

01/08/2007

Phenol Plant Solves Flow Measurement Problem

Non-contact ultrasonic meter eases maintenance and improves accuracy

03/25/2014