Dejelfa case study

CompAir supplies the compressed air system at the company’s largest combined cycle in Algeria

In December 2013, Duro Felguera won the EPC contract for the project and appointed CompAir to supply the compressed air system.

The combined cycle electricity generation power plant is composed of two generation power blocks, each one with a 2x1 configuration consisting of one power train with two gas turbines and associated heat recovery steam generators, plus one steam turbine, their auxiliaries, and the common systems for both generation power blocks, with a net output of approximately 2 x 800 MW.

Benefits at a glance

  • Turnkey project, engineered solution to match the customer’s needs 
  • Using a regulated speed compressor could easily save 35%
  • No oil or oil laden parts to dispose of, saving time and expense 
  • Lower speeds and balanced bearing loads extend the compression element service life to 36,000 hours for low-cost operation Cooler operating temperatures reduce component wear 
  • Significantly fewer moving parts means less to go wrong 
  • The combination of control and drive technology expertise, with water-injected screw compression technology, delivered an extremely cost effective operation with minimal servicing costs 
  • Redundant instrumentation for controlling all different variables 
  • Redundant PLC: local panel controller

Compressed Air Station description

CompAir initially completed the design and specification for the plant’s compressed air installation. A continuous feed of clean, dry and oil-free compressed air was required for the operation of the pneumatic instruments and actuators, in addition to the PP equipment such as bus bars, which was to be continuously pressurised.

The CompAir team devised an optimum solution for the application, comprising 4 x D50HRS-A air compressors, each with a cyclone separator that supply two vessels with compressed air. From here, the compressed air was divided into three lines – two control air lines, each with an adsorption dryer, and a service air line complete with refrigeration dryer. The installation also comprised six air buffers and a total of eight air receivers.

Automated plant control

The compressed air installation incorporates a PLC connected to the control panels for the main equipment and also the redundancy instrumentation, including auto regulated control valves – hard-wired and communicated signals manage the whole system without operator intervention.


Cost saving

The unique design of the oil-free DH-Series compressors, achieves lower speeds combined with lower operating temperatures resulting in both high efficiency and reduced component wear. Using a single-stage, direct-driven motor without gears or belts, maximises efficiency. Limiting the compressed air to application demand with regulated speed, ensures that no energy is wasted. The largest cost component of a compressor during its lifetime is the power required to run it. Using a regulated speed compressor can easily save 35% energy as it consumes just the energy required to do the job and no more. In addition, the compressor can be adapted to any operating regime the plant demands.

Energy saving

Water injection means lower temperatures, and lower temperatures means more efficient compression.

100% air purity

The DH series contains absolutely no oil anywhere in the compressor and has been certified ISO 8573-1 Class Zero (2010) and silicone free.


Optimum adsorption and regeneration capacity

Adsorption dryers provide regeneration capacity to ensure consistent dew point. Apart from that, they provide efficient removal of water vapor from compressed air. Besides, this dryer improves production efficiency and reduces downtime and maintenance costs.

In the regeneration process, the purge air becomes even drier, increasing its capacity to remove water from the saturated desiccant bed. The dry purge air mixture and the heat uses less energy to remove the water from the saturated desiccant bed than the purge air only.