Tight Crude Oil Can Cause Fouling in Shell and Tube Heat Exchangers

Editor’s Note: This content was last updated 6/17/24.

The shell and tube heat exchanger industry in North America is largely driven by the chemical and petrochemical industries. In 2023, approximately 25% of the market share for heat exchangers was attributed to the chemical and petrochemical industry. This percentage reflects the industry’s substantial demand for heat exchangers, driven by processes that require precise temperature control and energy efficiency in chemical production and petrochemical applications

Currently, the most significant producers of shale oil are Argentina, China, Canada, and the U.S. though others are beginning to take interest. This type of oil, also known as tight oil, is more challenging to retrieve and is extracted using hydraulic fracturing, or fracking.

Customized shell and tube heat exchangers are efficient for processing, but there are important considerations for manufacturers and operators. The refining process is highly prone to fouling, a common and harmful issue, especially with light tight crude oil. Fouling leads to lost production time, increased costs, and reduced profits, as operations must cease for cleaning. Additionally, fouling results in excess energy consumption and decreased throughput. The cost of crude oil fouling in the U.S. is estimated to be around $4.4 billion annually.

Asphaltene precipitation leads to accelerated fouling

Fouling in tight crude oil often results from asphaltene precipitation, which happens when tight oil is blended with other crude types. Refineries typically designed for specific oil compositions can experience bottlenecks with tight oil, especially in naphtha processing and crude overhead units. Blending tight oil with other crudes can mitigate this, but incompatible blends increase asphaltene precipitation. For instance, a blend of 20% tight oil and 80% other oil produces fewer asphaltenes than a 30-70 mixture. Tight oil’s higher naphtha content also accelerates asphaltene precipitation.

Prevent fouling through monitoring

To prevent fouling, manufacturers traditionally inspected machines periodically and recorded information manually. However, with the increased production of tight crude oil, which fouls more quickly, manual note-taking and periodic observation are no longer practical. Instead, using online monitoring capabilities is recommended. Wireless temperature and differential pressure measuring devices can constantly monitor the performance and efficiency of heat exchangers. This allows refiners to schedule maintenance proactively, minimizing the financial impact of downtime. Continuous monitoring also prepares maintenance staff for necessary repairs and indicates if additional parts need to be purchased in advance. Some exchangers have a bypass feature, enabling cleaning without halting production, but for those without this capability, advance knowledge of maintenance needs can reduce turnaround time and mitigate unforeseen obstacles.

More from the Enerquip Blog