Wet Scrubber Application Guide - TEC Engineering

1 Wet Scrubber Application Guide Impingement Plate Scrubbers Venturi Scrubbers Eductor Venturi Scrubbers SLY INC. TECHNOLOGY FOR A. CLEAN ENVIRONMENT. Three Types of Wet Scrubbers To Remove Vapors, Gases and Particulate Impinjet . Impingement Plate Scrubbers The Sly Impinjet Scrubber collects particu- lates, and absorbs vapors, and gases. High collection efficiencies, (99+%), can be achieved with low water consumption and minimum pressure drop. Venturi Scrubbers for Fine Particulates The Sly Venturi Scrubber offers more Venturi Scrubber advantages in separating and recovering ultra-fine particulates and liquid mists than other gas cleaning methods. Eductor Venturi Scrubbers Eductor scrubbers are designed to remove soluble gases and particulate by inducing a gas flow using high pressure liquid focused into a venturi throat.

2 Eductor Venturi Scrubber Impinjet Scrubber Basic Criteria for Sizing A Wet Scrubber The first step is to Example: absorption the following determine which type of 10,000 ACFM @ 450 F information is important: Sly Scrubber to select. containing # H2O/# - gas volume The nature of the pollutant dry air - process description or contaminant will The chart shows a - temperature determine if the Venturi, correction factor of Inlet - particle size Impinjet, or combination volume x correction factor = - moisture content Scrubber system is best outlet volume or 10,000 x - type of contaminant suited for your Application . = 7500 ACFM. The Scrubber For assistance in under- Sizing the Scrubber is would be sized for this standing your problem, call the next step.

3 The factors saturated outlet volume. your local representative or affecting sizing are gas flow For Impinjet scrubbers, Sly at 1-800-334-2957. rate, temperature, pressure, the maximum capacity is gas composition, humidity, based on shell velocity of 500. contaminant loading and feet per minute. Dividing the VOLUME CORRECTION CHART. desired outlet conditions. corrected or saturated 1000 . 2000 . 1250 . 1500 . 750 . Also, the availability of an volume by 500 yields the .40. INLET MOISTURE, #H20/#DRY AIR. 500 . 450 . 350 . appropriate scrubbing overall tower cross-sectional 250 . 225 ..35. 175 . 200 . liquid is an important area from which the diameter consideration. can be determined.

4 30. Gas streams entering a wet Scrubber may or may Example (continued): .25. not be fully saturated, 7500 ft3/min = 15 ft2 .20. however they will exit the 500 ft/min Scrubber fully saturated. Area = 15 ft2 = D2 .15. 125 150 . This process of saturation 4..10. results in a change in D=diameter . volume, temperature and Diameter = ft .05. density. The calculated diameter The overall Scrubber becomes the reference point .40 .45 .50 .55 .60 .65 .70 .75 .80 .85 .90 .95 size (diameter) is a for equipment selection. function of velocity of VOLUME CORRECTION FACTOR. (Refer to specific product saturated gas through the bulletin.). Scrubber shell. By knowing The approximate PARTICULATE COLLECTION EFFICIENCIES.

5 The moisture content of a particulate and/or mist 30' P VENTURI. 100. gas stream (generally efficiencies for Venturis and 20' P VENTURI. expressed as pounds of Impinjet scrubbers can be water per pound of dry gas) determined by the efficiency EXPECTED EFFICIENCY %. ET . and the inlet temperature; chart on the right. PINJ. 95 GE IM ET . 2 ST. A PINJ. the saturation temperature To determine the number E IM. TAG. 1 S. and saturated volume of Impinjet stages required content can be calculated. for the absorption of gases The volume correction such as acids, requires a 90. chart at the right can be complex calculation with too used for a close approxima- many variables to use a tion of the change in gas simple chart.

6 However, for volume. either particulate or 85. 0 PARTICLE SIZE, (MICRONS). 1. Impinjet Scrubbers Collect Particulates &. Absorb Vapors and Gases Rugged and uncompli- 4.) Both particle condensing and for heat Intimate gas/liquid cated in design, Impinjet collection and recovery, our designs can contact results in the Scrubbers can realize absorption of gases, accommodate high maximum collection efficiencies in excess of vapors, etc. can be hydraulic loadings. efficiency for particles and 99% on many types of done at the same time. droplets as well as dust or gases. Capacities 5.) Multiple stages can absorption (mass transfer). Operating Principles range from 500 to over be provided.

7 Of gases and vapors. When The gas passes up 100,000 CFM. Depending 6.) No moving parts used for absorption, low through the openings in upon Application , water to maintain. outlet emissions can be the perforated plates (trays). requirements vary from 7.) Extensive experience achieved by virtue of the which hold a bed of liquid. less than 1-1/2 GPM per with many applications Scrubber 's countercurrent The secret is in the 1,000 ACFM to a typical 3 available. operation. The Sly Scrubber 's design which GPM per 1,000 ACFM. 8.) Needs less scrubbing Impinjet Gas Scrubber is uses an impingement baffle Unique flexibility is fluid than most other able to reduce gaseous above each individual hole.

8 Furnished by Impinjet scrubbers. pollutants to any desired The tiny droplets, Scrubbers. Made with the 9.) Can handle high concentration if a created by the wetted future in mind, additional temperatures and sufficient number of plate baffles, are the heart of stages can be added to temperature stages is used. the collection process. existing installations to fluctuations. See data sheet for Gas velocities of 60 to improve efficiency to technical details. Cooling and 75 feet/second through the handle tomorrow's Condensing holes result in thousands of requirements without The outlet gas can be jets which atomize the increasing liquid con- cooled to less than 5 F liquid into droplets on the sumption.

9 There is no need above the temperature of order of 100 microns in to buy complete new units. the incoming liquid. Often diameter to clean the Benefits solvents such as alcohols, contaminated gas. This 1.) High absorption pentane, hexane, acetone, entraps the particles in the efficiency for gases ethylene glycol, chloro- scrubbing liquid. Each jet and vapors. Experts form, etc. are recovered aspirates liquid from the agree that plate towers from inert gas streams blanket of scrubbing fluid have the ability to such as nitrogen or carbon and results in a wetted remove gaseous pollu- dioxide. Chilled solvent is target surface on the baffle tants to any desired used as direct contact which is located just above concentration if a suf- condensing liquid and the point of maximum ficient number of removes the heat from the velocity (vena contracta).

10 Plates are used. This gas stream as it gains heat. In operation, the means high mass Scrubbers also recover Scrubber is highly transfer rates can be waste heat. Heat from pluggage-resistant. The achieved. dryers and other processes continuous violent 2.) 98+% collection that would normally be agitation of the blanket of efficiency for particles exhausted can be used to scrubbing fluid prevents 5 microns in size heat water being fed to the settling of particles and or larger. Scrubber almost to the wet flushes them away. 3.) These high efficiencies bulb temperature of the are achieved at a low inlet gas. For cooling and pressure drop. 2. Venturi Effect results in turbulent interaction of liquid and particulate-laden gas flowing through perforated plate and striking the wetted impingement baffle grid.