Don't Let Warm Weather Impact Ethylene Production

Effective operation of quench columns is key to success in olefins plants. Increased summertime cooling water (CW) temperatures cause costly throughput reductions. Recirculating the CW cools the ascending vapor that enters the bottom of the column and minimizes the temperature of the quenched gas entering the charge gas compressor. Lowering the temperature of the quench column gas ensures that its heavy hydrocarbon and water content are minimized, thereby maximizing charge gas compressor capacity and, therefore, ethylene plant throughput. However, this compressor often represents a significant summertime capacity limitation. Improved quench column cooling has enabled dramatic improvements in summertime plant operations at many of our clients’ sites:

• Enabled olefins production to approach rates seen during the winter months
• Minimized fouling of compressor blades by heavy oils to restore compressor efficiency
• Minimized wastage of compressor horsepower caused by excessive heavy oil and water vapors in quench gas
• Minimized heat loads on the compressor’s interstage coolers All ethylene plants suffer from some or all of these summertime issues that force throughput cutbacks, affecting profits significantly. So, what can be done to avoid these costly seasonal limitations and operate year-round at full capacity?

Improve heat exchanger efficiency

Higher summertime CW temperatures hurt quench column performance dramatically: the performance of the heat exchangers that cool the recirculating water degrades, and quench gas temperature rises. Also, these exchangers are subject to rapid fouling, so routine cyclical replacement of fouled units with clean units is practiced. One option is to provide additional rental heat exchangers while cleaning is carried out. Additionally, targeted cooling of the CW supply to these quench heat exchangers has proven highly effective in restoring quench column performance.

Aggreko’s process engineers can help you to assess system performance and suggest improvements to restore production. For example, if your heat exchangers are fouled, leaking, corroded, or simply struggling to keep up in warmer weather, we have a large inventory that can be deployed rapidly anywhere in North America. Aggreko’s heat exchangers meet the industry’s highest standards and are thoroughly cleaned and pressure-tested by a third party before each deployment. Our engineers are experts in heat transfer and use industry-standard software to ensure reliable, predictable performance.

Dedicated cooling towers

An additional strategy is installing a dedicated cooling tower loop to reduce the CW supply temperature to the quench exchangers by 5-10℉ below current summertime values, significantly improving quench column performance.

Aggreko has a vast fleet of cooling towers that can be used either permanently or just during the summer months. With their modular design and small footprint, they can be configured and scaled to meet the demands of any olefins plant. Our expert team will design the ideal cooling system loop to ensure a CW supply temperature within 4-5°F of the wet bulb temperature, usually a huge improvement over most existing plants. In an emergency, our cooling towers can be installed in a matter of days to reduce downtime and minimize financial losses.

Let Aggreko take care of your quench column limitations

Aggreko has industry-leading experience and process technology expertise to quickly resolve your quench column operating issues and safely restore production without requiring a plant shutdown. Our tailor-made solutions are field-proven to reduce compressor loading and blade fouling while maximizing interstage cooler performance. So get in touch with us today and let us show how we can help you take your olefins plant to the highest performance levels throughout the summer.

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