The key working principle differences between spray towers and venturi scrubbers are:

Spray Towers:

Operates through gravity-driven contact between falling liquid droplets and rising gas
Gas flows upward through a chamber while liquid is sprayed downward from nozzles
Lower pressure drop (0.5-2.5 inches water)
Better for removing larger particles (>10 microns)
Lower energy consumption
Limited gas-liquid contact time
Collection efficiency relies heavily on droplet size and distribution
Venturi Scrubbers:

Uses a converging-diverging throat section to accelerate gas flow
Creates intense turbulent mixing through high differential velocity
Higher pressure drop (10-100 inches water)
Very effective for fine particles (<2 microns)
Higher energy consumption due to high gas velocities
Excellent gas-liquid contact through atomization
Collection efficiency depends on throat velocity and pressure drop
The main distinction lies in how they achieve gas-liquid contact - spray towers use simple gravitational spray while venturi scrubbers employ high-velocity turbulent mixing for more intensive contact.

Would you like me to explain any of these aspects in more detail?