Ethylene Production and Quench Water Treatment Using Advanced Coalescence Technology

Source: Pall Corporation – Ethylene Quench Water

Overview

Ethylene is a critical petrochemical intermediate, widely used as a feedstock in the production of consumer and industrial products such as food packaging, plastic bottles, films, pipes, and antifreeze. The ethylene manufacturing process involves high-temperature pyrolysis (300–900 °C / 572–1652 °F) of hydrocarbon feedstocks such as naphtha and natural gas liquids (ethane, propane, butane) in the absence of oxygen to break down larger molecules into ethylene and various by-products.

Process Challenge

Pyrolysis By-Products and Quench Water Contamination

In ethylene crackers, residual heavy oils and hydrocarbons—particularly pyrolysis gasoline (py-gas)—can contaminate the process quench water. This contamination poses significant operational risks:

• Fouling of heat exchangers and boilers

• Reduced thermal efficiency

• Poor phase separation in downstream units

• Increased energy usage and maintenance burden

To enable the reuse of quench water in the Dilution Steam System (DSS), effective hydrocarbon removal is crucial.

Customer Requirement

Identifying the Separation Problem

At a mixed-feed cracker plant in Europe, process engineers required a solution to effectively remove free py-gas downstream of the coalescer in the DSS. Their objective was to:

• Minimize fouling and heat transfer loss

• Improve separation performance

• Enhance plant reliability and output consistency

They consulted Pall Corporation for a system upgrade recommendation.

System Conditions

• Flowrate: Up to 90 m³/hr

• Operating Temperature: 82 °C

Proposed Solution

Pall PhaseSep™ EL Coalescence Technology

Pall recommended upgrading to the PhaseSep EL Liquid/Liquid Coalescer, an advanced separation solution capable of:

• Removing dispersed hydrocarbons with high efficiency

• Reducing polymerization and fouling risks

• Enhancing heat exchanger and steam system performance

• Supporting stable ethylene production rates

Implementation and Results

Pilot Testing and Deployment

A 5-week pilot was carried out using the PhaseSep EL coalescer, preceded by a particulate pre-filter rated at ß23(c) >5,000 to protect against solid fouling.

Full-Scale Performance

After confirming the success of the pilot, Pall provided a rental skid for rapid implementation and retrofitted the existing filter vessels with optimized internals. The full-scale system achieved:

• Clear and bright quench water

• No visible free py-gas or hydrocarbons downstream

• Consistent long-term coalescer performance

Outcome

By deploying Pall’s advanced separation technology, the ethylene producer achieved improved process reliability, reduced fouling, and maximized output in both quality and quantity—meeting their operational and performance goals with confidence.

Request a Demo