Shell and tube heat exchanger with improved Anti-fouling properties

Abstract

A shell and tube heat exchanger comprising: a shell having an inlet end-cap attached to a first end of the shell, wherein an outlet end-cap is attached to a second end of the shell and a tube bundle being housed within the shell, said tube bundle including a plurality of parallel-spaced tubes that traverse the interior of shell from a first end to a second end of the tube bundle, and wherein a plurality of baffles are arranged within the shell supporting the parallel-spaced tubes of the tube bundle. At least a part of the shell and tube heat exchanger is provided with a coating comprising silicon oxide, SiOx.

Description

TECHNICAL FIELD[0001]The present invention refers generally to shell and tube heat exchangers allowing a heat transfer between two fluids at different temperature for various purposes. Specifically, the invention relates to a shell and tube heat exchanger which has been coated for improving anti-fouling properties and has in some embodiments been given predetermined, structural properties for ensuring that the coating remains on the shell and tube heat exchanger when it is used.BACKGROUND ART[0002]In many industrial processes fouling of heat transfer equipment is of concern. In order to keep a satisfying performance of the equipment regular service and cleaning it is necessary to remove build up of deposits on the heat transfer surfaces. The deposits arise e.g. from the fluids in the equipment, microbial growth and / or dirt.[0003]Shell and tube heat exchangers may over time get fouled which leads to a decreased heat transfer and increased pressure drop, and thus leads to an overall r...

AI Technical Summary

Benefits of technology

This patent is about improving the surfaces of a shell and tube heat exchanger to reduce fouling and make them easier to clean. The surfaces are coated with a special material called sol-gel, which lowers the surface energy and roughness, reducing fouling and making it easy to clean. The coated surfaces also have high resistance against wear and cracks, and do not compromise the heat transfer capacity of the heat exchanger. This improves the overall performance of the heat exchanger while reducing its size.

Problems solved by technology

In many industrial processes fouling of heat transfer equipment is of concern.

Shell and tube heat exchangers may over time get fouled which leads to a decreased heat transfer and increased pressure drop, and thus leads to an overall reduced performance of the heat exchanger.

Depending e.g. on the fluids used the heat exchanger may be seriously fouled and difficult to clean, thus requiring strong detergents and / or powerful mechanical cleaning over a substantial time period in order to restore the performance of the heat exchanger.

The cleaning may both be time consuming and costly.

The shell and tube heat exchangers are made of metals which have a high surface free energy that results in most liquids easily wetting the surfaces.

Also, when heat exchanger surfaces are produced the forming operation of the metal increases the surface roughness which often is associated with faster build up of fouling deposits.

A problem encountered with presently known antifouling coatings is the poor wear resistance of the coatings in applications with abrasive heat exchanging media, e g sand or other particulate material which enters the shell and tube heat exchanger with the heat exchanging fluids.

Furthermore, cracks in the coating may occur due to torque and tension forces acting in the shell and tube heat exchanger in applications under high pressures.

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