A different perspective

Nicholas Newman on why many refineries are now looking to gasket-free, compact plate heat exchangers as a reliable, cost-efficient alternative to traditional shell-and-tube heat exchangers.

Compact plate heat exchanger installation for heat recovery in a desalting process

The most common type of heat exchanger in process plants today is the shell-and-tube. However, shell-and-tube heat exchangers are associated with high maintenance costs and excessive downtime. In addition, low thermal efficiency results in high installation costs and large footprints as well as excessive energy consumption and emissions. Fully welded, gasket-free compact plate heat exchangers like Alfa Laval's Compabloc, on the other hand, are a well-proven and cost-efficient alternative that offers advantages like:

• Reduced maintenance costs and improved reliability
• Better thermal efficiency
• Reduced heat-transfer area for lower CAPEX
• Energy savings and reduced emissions (CO2, SOx, NOx)

Today Alfa Laval's compact heat exchangers have been in successful, long-term operation in many critical processes in over 180 refineries around the world. Alfa Laval's compact plate heat exchangers use corrugated plates between the heating and cooling media. This creates high turbulence and a cleaning effect that reduces chemical fouling. Compact plate heat exchangers also have a multi-pass arrangement with an overall counter-current flow, which means more heat can be transferred from one stream to another, or a heating media can be used that is just a few degrees warmer than the cold media. Together with the high turbulence, this allows high heat recovery and provides high heat-transfer coefficients, allowing significant size and weight reductions, low acquisition costs (CAPEX) and reduced energy use and emissions.

Reliability and availability

Alfa Laval's compact plate heat exchangers have proven to provide many times longer uptime in critical refinery processes than shell-and-tube heat exchangers.

For example, one of the longest operating installations is in a bitumen refinery in Europe. Here, 14 compact plate heat exchangers are in operation, the oldest since 1996. They have replaced shell-and-tube heat exchangers in duties such as ADU fraction cooling, VDU overhead vapour condensing and bitumen heating and cooling.

The old shell-and-tube heat exchangers required cleaning and inspection yearly, which took a full week. The compact plate heat exchangers, on the other hand, require only a single day of chemical cleaning every third year. In total, for the 14 units, the refinery has reduced maintenance costs by 96 percent.

Lower acquisition costs

Because compact plate heat exchangers are so efficient, they require relatively little heat-transfer surface compared to shell-and-tube heat exchangers. This means that one compact plate heat exchanger can often replace a number of shell-and-tube heat exchangers. So there are significant savings to be had in capital outlay. For example, in one planned installation, 12 compact plate heat exchangers will replace 28 shell-and-tube heat exchangers for a savings of €50 million. In addition, the small size of compact plate heat exchangers means that they require only a fraction of the space needed by shell-and-tube heat exchangers. So there are also savings to be had on foundations, constructional steel work, and the like. Finally, lower energy use due to better heat-transfer efficiency and increased heat recovery gives reductions in operating costs and CO2, SOx, and NOx emissions. 

Global company, local insight

With a staff of over 100 specialists at offices in the UAE, Saudi Arabia, Iran, Egypt and Pakistan, Alfa Laval can provide complete solutions for its customers wherever they are, at every stage of their projects. Alfa Laval acts as a partner to its clients, evaluating their needs and processes and helping them design and implement the most efficient, reliable and cost-effective solutions possible.

In addition, Alfa Laval has service centres in the UAE and Saudi Arabia. This allows them to carry out field service, provide performance agreements, condition-based monitoring and maintenance of heat exchangers across the Middle East.

Nicholas Newman is currently the Regional Process Division Manager for Alfa Laval Middle East Ltd. He has over 15 years of experience working to bring efficient solutions to oil and gas companies, refineries and engineering companies around the globe.