C R E A T I N G V A L U E T H R O U G H N E T W O R K I N G – U S E R S G R O U P 2 0 0 3

Relying Entirely on the Honeywell TPS DCS Systemfor Computing and Control Functions

Ted Porter, Enterprise ProductsBarry Payne, Payne & Associates

Ted Porter is the Process Control Supervisor for EnterpriseProducts. He has 23 years of experience in the Oil and GasRefining Industries. He leads a team of Process Control Engineersand Specialists and Material Balance supervision. He alsodeveloped and maintains Enterprise’s Process Information systemincluding 34+ interfaces, 9 PHD’s and 3 PI Servers.

Ted has been with Enterprise for ten years in Process Controland Engineering and as an Instrument Engineer in Maintenance.Before joining Enterprise he was a Process Control Engineerwith BP Research in Cleveland Ohio. Prior to that, Ted hadbeen with BP Oil and Mobil Oil at their Ferndale, Washingtonand Augusta, Kansas Refineries.

Ted has a Bachelor of Science degree in Chemical Engineeringfrom the University of Missouri – Rolla.

Barry Payne is the founder and President of Barry D. Payne &Associates, Inc. The company provides a range of process-related services including advanced process control for the naturalgas and petrochemical industries. Barry has worked in theapplication of advanced regulatory control for Cryogenic gasprocessing and NGL Fractionation since 1984.

Barry founded Barry D. Payne & Associates, Inc. in 1993 toprovide a range of services for the process industries, includingsystems integration, process design consulting, and advancedprocess control solutions. He was responsible for developingseveral new advanced regulatory control designs for CryogenicGas Processing. Prior to founding Barry D. Payne & Associates,Inc., Barry worked as a senior systems specialist with DowChemical Company in Freeport, Texas for ten years, and as aDigital Controls Specialist with the then Fischer & Porter Companyin Houston, Texas for four years.

Barry has a Master of Chemical Engineering degree from RiceUniversity and is currently serving on the Rice EngineeringAlumni Board of Directors

Ted Porter

Barry Payne

C R E A T I N G V A L U E T H R O U G H N E T W O R K I N G – U S E R S G R O U P 2 0 0 3

Relying Entirely on the Honeywell TPS DCS Systemfor Computing and Control Functions

Abstract – A comprehensive package of Advanced RegulatoryControl strategies has been commissioned on Enterprise’sSeminole and West Texas Natural Gas Liquids FractionationTrains at Mont Belvieu, Texas. Relying entirely on the HoneywellTPS DCS system for computing and control functions, thesestrategies simultaneously

1. Improve process stability, decreasing operator workload.2. Reduce variability in compositions significantly (Standard

deviation or Sigma reduced by a factor of 3-6), permittingmuch closer operation to product specifications.

The reduction in variability alone resulted in an estimatedpayout of less than six months. The Enterprise Fractionators inMont Belvieu, Texas have a combined capacity of 210,000BPD. It incorporates a high degree of heat integration, andprocesses liquids from several major gas plants along the GulfCoast. Enterprise was convinced that additional benefits wereachievable by employing advanced composition control. A pro-ject was commissioned, and a team assembled consisting ofcontrol specialists from Enterprise and from Barry D. Payne &Associates, Inc. The engineered solutions employed included:

1. Dynamically compensated model based estimates of productcompositions using tray temperatures, tower pressures andchromatograph analyses.

2. Control of integrated energy and material balance models.

RELYING ENTIRELY ON HONEYWELL TPS FOR COMPUTING & CONTROL FUNCTIONS

Minimizing Loss of Higher-Valued ComponentsMaximizing Production Rates

Ted Porter Enterprise Products Co.

Presented by:Ted Porter - Enterprise Products Co.

Mont Belvieu, Texas, U.S.A.and

Barry D. Payne - BDP Inc.Stafford, Texas, U.S.A.

With Special Thanks to the Implementation Team:Bubba Rossow - Enterprise Products Co.

Ron McDaniel - Barry D. Payne & Associates, Inc.Ray Dollar - Barry D. Payne & Associates, Inc.

TECHNOLOGY CURRENTLY APPLIED AT TWO LOCATIONS

Mont Belvieu Seminole & West Texas FractionatorsBaton Rouge Fractionator

Mont Belvieu Complex

Baton Rouge Fractionator

• Facility: Seminole & West Texas Fractionator, Mt. Belvieu, Tx.

– Built: initially 1982 & 1980, West Texas expanded in 1996

– Capacity: 200,000 BPD [Nominal] – Feed: Pipeline NGL fed by several Gas

Processing Plants and a Refinery.

• Facility: Baton Rouge Fractionator, Port Allen, La.– Built: 1998-1999 [Plant started in September, 1999.]– Capacity: 60,000 BPD[Nominal]– Feed: Pipeline NGL fed by several Gas

Processing Plants and a Refinery.

Installed Plant Control Systems

• Honeywell TPS Distributed Control System with GUS, AM, HM, & HPM

• AA online analyzer system interfaced to the DCS

• Honeywell PHD Process Historian System

Seminole Control System

West Texas Control System

Mont Belvieu APC Challenges

• Fed by many pipelines with sudden and large changes in fractionator feed flow rates.

• The analyzer data is often inconsistent and unreliable. Original equipment columns still in service. Part of problems were lack of insulation and heat tracing on deeth ovhd, heavy filtering, and slow update rates.

• The three deethanizers exhibited hydrate formation with the Seminole deethanizer being the worst.

• Deethanizers exhibit flooding in their stripping sections due to high production rates at lower ethane feed concentrations.

• Hot oil supply temperatures vary significantly.• Sudden and large changes in fractionator feed flow rates .• Feed quality problems were/are numerous and not well known in advance.

Baton Rouge Fractionator (BRF) Challenges

• Fed via 23 miles pipeline from salt dome storage.• No outlet for off specification product.• Customer for products required the plant be on specification on all products

or shutdown.• No effective rerun facilities.• Production “tankage” limited to 15 to 30 minutes, at full rates, depending on

product type.• Feed quality problems were/are numerous and not well known in advance.• Single gas turbine is plant refrigeration and source of air for hot oil heater.• Operations personnel felt so over loaded that they did not think they could

operate second facility.• Multiple plant constraints needed to be managed.

BRF APC Project Objectives• Improve the regulation of product qualities.• Reduce significantly operator intervention.• Maximize “blending” of lower value products into high value

products.• Minimize propane and gasoline losses.• Add capability to maximize plant feed.• Push against multiple constraints.• Must be implemented during normal operation, with minimum

interruption.• Plant must be able to operate during significant feed composition

changes with little operator intervention.

• The variation in product quality is significantly less.• Operators report that the unit is much easier to operate.• All product blending vastly improved. Propane losses are

significantly reduced.• Gasoline losses are minimized with tighter RVP control.• Feed Maximizer has been commissioned.• Controls have proven to be very robust with little need for

intervention to “retune” or “rebuild” models.• Operators have successfully taken on the operation of a second

facility, with no additional Control Room Staff.

BRF APC Project Results

BRF Control Strategy Hierarchy

Tower ARC

QV MV QVMVSep MB

The Plant

Tower SP ManagerCV

QSPQSP

Feed Maximizer

FSP

CV

CV

BRF APC Objective: Facilitate Optimization

• Feedforward controls that facilitate optimization.

• Emphasis on the quality of the greater valued product.– Controlled by material balance split.

• Constraints override the quality control of the lesser valued product.– Controlled by liquid-to-vapor ratio.– Affect losses of the greater valued product.

BRF APC Objective: Manage Setpoints

• For the quality of the more valued product.– Minimize control margin. – Maintain process capability.

• For the loss of the more valued product.– Minimize in less valued product.– Honor constraints.

BRF APC Objective: Maximize Production

• Honor operator-set limit on the feed rate.

• Honor operator-set limits on losses of more valued product.

• Honor plant-wide constraints.

Baton Rouge APC Control Structures

Overhead BottomsMV CV MV CV

Deethanizer L/V Propane % Internal MB Ethane LV%Depropanizer L/V Isobutane % Internal MB Propane LV%Debutanizer Direct MB Gasoline RVP Minimum Move NADeisobutanizer Direct MB n-Butane % Heat Pump – NA NA

Deethanizer Overhead Propane

0.0

1.0

2.0

3.0

4.0

5.0

LV % Average R/F ratio = 0.77Average R/F ratio = 0.79

Jan. 1-31, 2000, 1 hr. data before ARC Implementation.

Max Spec = 5 LV%

Aug. 11-18, 2000, 12min dataafter ARC Implementation

Obj: Maximize Propane Yield

Less Variation & Lower Losses of Propane

BRF

Deethanizer Bottoms Ethane

0.0

1.0

2.0

3.0

4.0

5.0

LV %

Average R/F ratio = 0.79 Average R/F ratio = 0.77

Jan. 1-31, 2000, 1 hr. data before ARC Implementation.

Aug. 14-18, 2000, 12min dataafter ARC Implementation

DeC3 Ovhd RVP Max Spec = 208 psia Obj: Maximize Propane Yield

Reducing control margin!

BRF

Depropanizer Overhead Vapor Pressure

160

170

180

190

200

210

220

PSIA

VP Max Spec = 208 psia

Jan. 1-31, 2000, 1 hr. data before ARC Implementation.Cpk = 0.97Control Margin = 13.4 psia.

After commissioning DeC2 bottoms ARC.Cpk = 2.54Control Margin = 6.27 psia.

Commissioning DeC2 bottoms ARC

Aug. 11-18, 2000, 12min dataafter DeC2 ovhd ARC Implementation

BRF

BRF Deethanizer Results

• The key component variation was reduced.– Increased bottoms flow.– Lower propane losses. – Less propane RVP giveaway.– Increased Process Capability.

BRF APC Project Benefits

• Significantly reduced composition variability.– Sigma reduced by a factor of 3-6.

• Improved management of impurity setpoints.– Increased throughput capability. – Increased yield capability. – Increased energy efficiency capability.

• Improved process stability.– Decreased operator workload.

BRF APC Strategy Benefits

• A sustainable technology.– Relies entirely on DCS based strategies.– Requires less maintenance and ongoing support than

other types of enhanced control.– Reduces control system training demands. – Uses normal DCS operator interface.– Continuously compliant with DCS version upgrades.