VenturiPak Scrubber

Breakthrough Technology Replaces Conventional Scrubbers and Wet ESPs

The VenturiPak scrubber is a result of re-examining and optimizing the venturi concept to achieve high collection efficiency at modest energy consumption (i.e. low to medium pressure drop).

The fine particulate fraction in furnace stack off-gases is comprised of fine solid particles (< 1 micron), and condensed solid and liquid aerosols resulting from the cooling and sub-cooling in the scrubber. These fine particles are problematic in that:

  • They are the most optically active, so that even in low concentration, they affect stack opacity.
  • They may contain significant concentrations of heavy metals.
  • They are most difficult to capture, requiring very high energy for conventional venturi scrubber systems or the addition of a Wet Electrostatic Precipitator (WESP).

The EnviroCare VenturiPak places the scrubber components in proper sequence rather than the traditional practice of placing a high energy venturi directly following the quench section. The VenturiPak scrubber incorporates the latest technological advances in wet scrubbing and atomization technologies. Features of the system include:

  • A quench section with an effective spray system and a low energy (2-5" ∆p) venturi to capture over 90% of the particulate.
  • Sub cooling following the quench converts any condensables into particulate and "grows" the heavy metal particulate, both usually sub micron, for subsequent capture in the venturi stage.
  • Water atomization with a MicroMist(TM) nozzle at the entrance of each venturi.
  • Water controller to compensate for variations in gas flow volume.
  • Utilization of multiple "near true" venturi tubes to maximize energy recovery.

Each component is designed for durability and is integrated into a state-of-the-art air pollution control system.

The VenturiPak scrubber performance has been verified through test results on small (±1000 ACFM), medium (±10,000 ACFM) and large (65,000 ACFM) installations. The system, with a local controller, is designed to provide high removal efficiencies over a wide range of gas volumes. It is also designed to remove pollutants not included in the 503 regulations, such as condensables, acid gases, soot, and hydrocarbons.

The design places each scrubbing stage in a logical sequence much like arranging screens for a sieve analysis where the screens are stacked with the coarsest first, then grading down to the finest screen. The design concept places a low energy venturi quench section first. The quench section captures more than 90% of the ash, sand and other particulate. Velocity in the quench section remains low, eliminating the need for wear plates or special wear resistant material.

The gases then enter the bottom of the scrubber and continue upward, passing through impingement trays for sub-cooling and further particulate removal. Sub-cooling serves to convert condensables to particulate and to "grow" the heavy metals, most of which will be sub-micron, for subsequent capture in the venturi stage. SO2 also becomes more soluble in the cooler water and is further reduced.

The gases pass upward and into a zone of atomized water at the entrance of each of several "near true" venturi tubes. The direct contact of the sub-micron particles with the small water droplets accomplishes removal of virtually all the remaining particulate including aerosols and soot. Table I shows that the gases leaving the venturi stage contain very little particulate or SO2 thus meeting stringent emission levels.

Following table shows an example of gas volumes, temperature, pressure drop and pollutants exiting each stage in the scrubber system.

Gas Quantities and Pollutants through Successive VenturiPak Scrubber Stages
Gases exiting scub stage Inlet Gas Quench Section Tray Sub-Cooling Venturi Stage
ACFM 40,760 21,061 11,943 12,436
SCFM 17,334 19,251 12,063 11,909
Temp °F 907 176 104 101
∆p inches w.c. - 3 5 20
Ash lb./hr. 1,668 66 17 0.2
SO2 lb./hr. 130 120 10 0.7

Note: Total ∆p for scrubber system is 29" w.c.

Particulate removals are based on EnviroCare operating data and established calculations.

Heavy Metals:

Recent tests conducted on municipal sludge burning (either fluid bed or multiple hearth incinerator) with a VenturiPak scrubber showed heavy metal removals for As, Cd, Cr, Ni. and Pb of 99.8% or greater. Mercury removal was 93.2%, which indicated that very little elemental mercury was present. NOTICE: The scrubber will capture a high percentage of bound mercury, but will have little, if any affect on elemental mercury.

Product Strengths


Expertise

  • Advanced Scrubbing Technology
  • Improved Scrubbing Sequence
  • Independent Atomization of scrubbing droplets
  • High Collection Efficiency of Sub-micron Particles
  • Proven Superior Performance with Predictable Results
  • Pilot Scrubber Available for Testing
  • Applied on MHF's and FBI's

Customer Focus


  • Available as Retrofit or New
  • Service Satisfaction
  • Broad Air Pollution Control Expertise