(84d) Successful Implementation of Advanced Process Control in Cryogenic Plants

Successful Implementation of Advanced Process Control in Cryogenic
Plants.

Tom Lyndrup and Greg Rogers

Enterprise Products LLC

Houston, Texas

Rafael Aguilar and Duane Morningred

Honeywell Process Solutions

Houston, TX, and Camarillo, CA, USA

Paper to be presented at the 2012 AIChE Spring meeting,
Houston, Texas

April 1-5, 2012

  Abstract

Enterprise Products Partners L.P is a natural gas and crude oil pipeline company
with headquarters in Houston, Texas. It has 18,368
miles of natural gas pipelines, 13,297 miles of NGL and petrochemical
pipelines, 813 miles of Gulf of Mexico crude oil pipelines, 26 Gas Processing
plants, 19 NGL and propylene fractionators along with Storage (Salt Dome),
Drilling Platforms and NGL Terminals.

The Meeker Gas Plant 1 is a new process unit in
Colorado's Piceance Basin, started up in late 2007 with a capacity to process
750 MMcf/d of natural gas and is capable of extracting up to 35,000 b/d of
natural gas liquids (NGLs).  Meeker, the largest natural gas plant in the
continental United States, serves the Piceance Basin and other area deposits
comprising the nation's fastest-growing natural gas field, increasing export
capacity and providing gas to downstream markets through four major pipelines. Phase
II of the complex (completed in the third quarter of 2008), doubled the processing
capacity at Meeker to 1.5 Bcf/d of natural gas and 70,000 b/d of NGLs.

Enterprise Products wanted to maximize their Meeker,
Colorado Cryogenic I plant's recoveries. This plant is subject to continuous
changes in production plans, feed composition and pipeline constraints, which
makes control difficult. The goal was to increase the recoveries by at least
1%.

The solution at Meeker Gas Plant utilized Honeywell's Multivariable
Predictive Control applications that have steady state models. Step Testing was
minimized due to the controller characteristics and the additional tools for
online model ID used during the project implementation.

Since the initial commissioning, Enterprise Products has
continued to enhance the applications finding new sets of variable limits and
automatic update for optimization limits based on process conditions.  In
addition, the operator workflow has been improved, since the focus is now to
understand the unit overall problem and search for a solution, instead of
changing limits and setpoints to multiple controllers all the time. APC
displays have been effective to show the current process constraints to
increase production, as well as improve operational consistency across the
multiple operation crews.

This paper summarizes the existing APC and
Optimization solution and discusses the details of how the control strategy was
recently implemented.