Cooling of process media

And processes in the chemical industry

2-stage NH₃-refrigeration system for cooling dichloromethane to -42°C

High availability and short maintenance and inspection intervals, alongside the highest safety standards, are often required in refrigeration systems for the chemical industry.

To meet these requirements, ARCTOS collaborates with you to develop a plant concept and carries out an individual system design.

REQUIREMENTS

The two-stage refrigeration system was developed and manufactured for a chemical industry company in an industrial park according to the described requirements. The goal was to cool dichloromethane to -42° C in two separate refrigeration circuits.

In order to achieve the required evaporation temperature of -44° C and to avoid a complex cascade system, the NH₃ system was designed to operate in a vacuum range (approx. 0.6 bar(a)).

This necessitates certain structural measures, which had to be carefully considered during the system design.
 

R&I DIAGRAM

The flow diagram shown below illustrates the schematic layout of the refrigeration system. To achieve the low evaporation temperature, the NH₃ screw compressors are designed in a two-stage configuration.

The ND and HD levels are integrated into a single unit and feature an ECO intermediate feed for additional energy efficiency.

The refrigeration system is an NH₃ system with two redundant refrigerant compressors, based on availability, each with separate 500V electric motors, operated with variable frequency drives (VFD).

The implementation of the control cabinets for the main drives with VFDs in 500V was part of the tasks, as well as the planning and execution of the piping on the dichloromethane side.

The system was built on a steel base frame in Sörup to minimize the assembly effort at the customer’s site.

The piping for the dichloromethane circuit was also fabricated in Sörup.