In Alkyl Ketene Dimer (AKD) wax plants, various types of heat exchangers may be used depending on the specific process requirements and design standards such as ASME Section VIII Div 1 & Div 2, TEMA, API 660, HTRI, and PVElite. Here are some common types of heat exchangers that could be employed:

1. Shell and Tube Heat Exchangers:

   • These are versatile and widely used in industrial applications including AKD wax plants.

   • Variants include fixed tube sheet, U-tube, and floating head designs.

   • They are capable of handling high pressures and temperatures, suitable for ASME Section VIII Div 1 & Div 2 requirements.

2. Plate Heat Exchangers:

   • Compact and efficient for heat transfer.

   • Often used where space and weight are critical factors.

   • Can be designed to meet TEMA standards and ASME requirements.

3. Air Cooled Heat Exchangers (ACHE):

   • Utilized when cooling water or other fluid is limited or not available.

   • Design considerations typically align with API 661 standards.

4. Double Pipe Heat Exchangers:

   • Simple design suitable for low-pressure and low-temperature applications.

   • Often used in smaller-scale processes or where efficiency is less critical compared to space constraints.

5. Plate-Fin Heat Exchangers:

   • Used for applications requiring high efficiency in compact spaces.

   • Designs can be customized to meet specific requirements, potentially complying with TEMA standards.

6. Spiral Heat Exchangers:

   • Suitable for handling fluids with high fouling tendencies or fluids with high viscosity.

   • Can be adapted to meet ASME and TEMA standards depending on the design specifics.

7. Compact Heat Exchangers:

   • Includes brazed plate heat exchangers and welded plate heat exchangers.

   • Known for high efficiency and compact size, suitable for various industrial applications.

Each type of heat exchanger has its advantages and is selected based on factors such as heat transfer efficiency, space availability, fluid properties, pressure and temperature requirements, maintenance considerations, and compliance with relevant design standards like ASME Section VIII Div 1 & Div 2, TEMA, API 660, HTRI, and PVElite. The choice depends on the specific needs of the AKD wax plant and the preferences of the plant designers and operators.