Automation system permits manufacturing excellence

An Emerson Process Management - Systems and Industry product story

Edited by the Engineeringtalk editorial team Apr 3, 2003

Huntsman Petrochemicals at Wilton on Teesside chose DeltaV from Emerson Process Management as a modern digital automation system for its existing Paraxylene plant.

Huntsman Petrochemicals at Wilton on Teesside chose DeltaV from Emerson Process Management as a modern digital automation system for its existing Paraxylene plant.

The company's key objective in upgrading the control was to enable performance improvements, in terms of efficiency and throughput.

Huntsman expected that the advanced process control modules available within DeltaV would achieve the required increase in plant output, and cost reductions.

The Paraxylene manufactured at this plant is used as a raw material in the production of polyester fibres and resins: end use examples include clothing and soft drinks bottles.

The plant runs continuously, and shutdowns are few and far between, maybe once in 3-4 years: the plant output provides important feedstock for other plants in the area.

So the initial problem was to switch control of the process from the original control panels to the DeltaV, with the plant live, and without losing production.

This was achieved using a combined task force of Emerson and Huntsman personnel, and 1600 loops were cut over to achieve this, in phases, over a six month time-scale.

The task force actually did this twice, without losing any production time, as once the DeltaV control had been established alongside the old control panels, the DeltaV was then relocated to a new purpose built control room.

Model predictive control was applied to the refrigeration plant, which had been identified as causing a plant bottleneck.

By driving the refrigeration plant harder, chilling capacity increased, and therefore the overall production output also increased: a 10% improvement is reported.

Next, historical trending systems were used to achieve smoother plant running, by finding stable operating conditions and reproducing those conditions.

Overall this smoother running added plant capacity of several percentage points.

Tom Liddle, Paraxylene Plant Manager, comments: "DeltaV has shown me that we can enhance the plant: the information that comes out of it is second to none, and just simply looking at the production rate since we installed DeltaV, speaks for itself.

The addon APC systems are pushing the plant to the boundaries of the next bottleneck".

The experience gained by Huntsman Petrochemicals, and the approaches and benefits possible using advanced control and the DeltaV automation system, will be presented in papers at the Manufacturing Excellence Conference on Teesside at the end of April.

Several presentations will discuss "Finding the hidden plant" within an existing facility, and cover "Revamping and debottlenecking" to increase production output.

Manufacturing Excellence is a collaborative venture between Huntsman International, Aker Kvaerner and Emerson Process Management, joined by Action Energy and the ISA England section, to enable process engineers and plant managers to benefit from shared experience of modern automation techniques.

Other invited speakers are from such companies as Astra Zeneca, BP Amoco Chemicals, Ineos Chlor, Associated Octel and Shell Global Solutions.

Huntsman is placing goals of further improvements on the Paraxylene plant, and looking for quality improvement to 99.7% product purity.

With the DeltaV installed and working well, Tom Liddle acknowledges there are some dated instruments at important points in the field, which are the focus for the next phases of the plant upgrade.

Instability at critical control points can reflect on plant running and introduce variability, which means running at below optimum levels.

The approach adopted is to use modern intelligent instruments interfaced using fieldbus architecture, and tap into the process and plant diagnostics using the AMS facilities within DeltaV, working in an overall PlantWeb environment.