Project news: PetroChina releases results of polymer process optimization

Offering a rare peek behind the operating curtain, PetroChina has published detailed results of implementing an Aspen Technology control solution. The specific plant involved in the study is the Mitsui high density polyethylene unit in Daqing, China. The improvements include a combination of increased capacity, higher product quality, and lower operating costs.

PetroChina implemented AspenTech’s aspenONE advanced process control for polymers solution on the HDPE unit, and reports that it has calculated annual savings of $640,000—equivalent to $8 per ton—through increased yield and reduced usage of reactor consumables. These savings, combined with a 28% decrease in off-specification material produced during grade transitions, have provided PetroChina with a rapid return-on-investment.

“We are delighted with the performance improvements achieved using the aspenONE advanced process control solution,” says Mr. Cao Jingliang, chief engineer of the PetroChina Daqing polyolefin plants. “AspenTech’s unique control technology coupled with the domain expertise of its polymers specialists were key contributors to the success of this project. Being able to automate even the most complex of transition strategies, such as a reactor configuration change, is a significant breakthrough and has enhanced our competitive position.”

Blair Wheeler, senior VP, AspenTech, adds, “China is now a major producer and consumer of polyolefins, and PetroChina is investing in innovative technology to maintain its position as a leading player in this highly competitive marketplace. With its ability to optimize even the most complex product transitions, the advanced process control for polymers solution is delivering significant operational benefits and a fast return on investment for a rapidly growing number of polymer producers worldwide.“

The aspenONE solution formed the basis of a comprehensive optimization strategy on the 80kt/yr HDPE unit. PetroChina set specific objectives for the project:

• Maximize production yield and production rate;

• Stabilize reactor operation;

• Reduce catalyst consumption;

• Minimize venting; and,

• Reduce the amount of off-specification product manufactured during product grade transitions.

That last item was a key requirement due to the difficulty of automating and optimizing product transitions, which the company says are typical of the Mitsui HPDE process.

PetroChina reports the following results of the program:

• Increased production capacity by 2.9%;

• Reduced transition off-specification material by 28%;

• Reduced catalyst consumption by 6%;

• Reduced hydrogen consumption by 22%; and,

• Reduced ethylene loss by 3 kg/tPE.

Read a recent article online from Control Engineering , “Effective Process Planning and Scheduling in the Olefins Industry.”

—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com ,
Control Engineering Weekly News

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