Gas Conditioning Tower
Redecam’s GCT provides two different water injection systems: the spillback injection system based on spillback lances, and the dual media injection system, where water is atomized by compressed air.

Spillback Injection System

A conditioning tower equipped with a spillbackspray system and high-pressure centrifugal pump is designed to force water through a set of nozzles located inside the tower. The water pressure energy is sufficient to overcome the water cohesion forces and produce a fine mist.

When the gas volume is a small percentage of the design volume, less cooling water is required. To avoid poor atomization and uneven water distribution in the gas, two independent nozzle groups can be installed:
- one set of nozzles, close to the tower center, would be used when the gas and water volume requirements are low
- a second set of nozzles would be added to supply additional water when the system is operating closer to the design conditions.

In the mechanical system the water pressure delivered to the nozzles is constant. The excess water (above the volume actually required for gas cooling) is drawn off through an electrically or pneumatically operated two-way control valve and a return pipe to the feeding water tank.

This valve is opened (or closed) to allow more (or less) water to flow back to the water tank and therefore controls the gas temperature. When the return pipe is totally closed all the water is forced into the conditioning tower for maximum cooling effect.

Two flow-meters (one in each of the feed-ring and the draw-off rings) measure the water flows, the differential being the water volume actually injected.

Dual Media Injection System

In a dual media system (water + compressed air) the compressed air provides the energy to overcome the water cohesion and to produce a fine mist. Water at low pressure (about 3 bars) is mixed with compressed air directly in the nozzle. 
In comparison with the spillback, this system is more efficient and produces smaller water particles. That reduces the required gas retention time in the tower, then its size. 

In the dual media systems, less quantity of gas flow requires reduced cooling water volumes, the particles atomization is not detrimentally affected, since the specific compressed air consumption increases when the water volume decreases.

The water delivered to the ring, which feeds the nozzles, is controlled by a 3-way regulation valve. The excess water is by-passed directly to the feeding water tank. The water flow delivered to the nozzles is measured by a flow-meter downstream from the 3-way valve.

The compressed air pressure is a function of the water pressure and is controlled by a pressure regulator on the air piping