Petrochemical RO plant

Case study

Emotron VFD improving the efficiency of a petrochemical refinery

As a petrochemical company expanded to become the largest facility in the Middle East, Emotron drives were chosen for their durability, modular flexibility and service support.

Emotron high power VFDs built up with unique Power Electronic Building Blocks (PEBBs) were selected for the high pressure pumping system of the critical RO plant providing demineralised water for the plant processes, firefighting requirements and human needs.

From a valve controlled membrane pressure system to variable speed pumping

In the first phase of the project a valve controlled membrane pressure system with pumps on fixed speed was chosen. This led to various problems:

Mechanical problems with bearings and pump impellers due to rush starting
High noise in the process area due to the high pressure system and throttling mechanism
Poor system efficiency
Inability to maintain set pressure under all conditions

As a result, a variable speed pumping system incorporating VFDs for motor speed control was chosen for the high pressure pumping system in the second phase of development.

The Emotron PEBB modular system

Emotron high power VFDs are built up by combining power modules called PEBBs (Power Electronic Building Blocks).

Each PEBB is a complete VFD in itself comprising of input semiconductor fuses, rectifier, DC capacitors, chokes and inverter IGBTs – with only the control board missing. Multiple PEBBs are connected to a common control board and function as a single unit.

This makes it excellent for redundancy, scalability and ease of service.

Interchangeable PEBB for critical applications

The PEBB concept has been a highly valued characteristic in the petrochemical industry, securing operational efficiency at all times, due to:

Redundancy feature for critical applications
Each PEBB module having its own semiconductor fuse which limits possibe damage to that module only
Lower spares inventory as parts are common
Interchangeability of PEBB modules thereby ensuring that critical pumps can be kept operational even in case of VFD failure
Easy for maintenance personnel to remove PEBB modules and repair them in workshop