(122g) Advancements in Spray Type Tray Internal Design and Its Industrial Application

Traditionally columns are classified into packed or tray type based on the mechanical structure of the column internals. In this paper, instead, the types of phase contact are used to characterise the intensity of the mass and energy transfer in a column. Three types of phase contact are discussed below, using the gas-liquid system as an example:-

The Film Type as in a packed column

• The liquid flows as a film or film mixed with droplets on the surface of packings, while gas rises through the opening of the packing as in a packed column.

Bubble Type as in a bubble cap, sieve or valve tray

• The gas bubbles through a liquid layer on top of a tray. 
• The gas is the dispersed phase, while the liquid is the continuous phase. 

Spray Type as in a vertical sieve tray or ChuangJu’s proprietary high performance spray trays

• The gas rises through the opening in the tray, while the liquid enters into, for example, a vertical sieve cap, through a gap between the cap and the tray floor.
• Inside the cap the liquid is drawn up, by the liquid phase hydrostatic pressure and the dynamic lifting of the rising gas. The liquid is broken into droplets, impinges to the top of the cap, and then is sprayed out through the vertical sieve holes.
• In the spayed type, the liquid is the dispersed phase and the gas is the continuous phase. 

The spray type of contactor offers higher mass and energy transfer efficiency due to the following reasons:-1) Increased total area of liquid-gas interface;2) Longer phase contact time;3)Faster interface renewal and 4) Shorter diffusion path for liquid molecules.

Based on the operational experiences gained from over 1,800 industrial columns for the last 25 years by Tianjin ChuangJu Technology, the advantages of the spray type contactor compared with a traditional bubble type or a film type contactors are follows:-

• Increased column capacity,
• Lower pressure drop,
• Wider operating window,
• Higher resistance to blockages,
• Lower foaming tendency, and
• Lower maintenance.