Wet Scrubber Application Guide

Wet Scrubber Application Guide Impingement Plate Scrubbers Venturi Scrubbers Eductor Venturi Scrubbers Three Types of Wet Scrubbers To Remove Vapors, Gases and Particulate

Impinjet® Impingement Plate Scrubbers The Sly Impinjet scrubber collects particulates, 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.

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 0.15# 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 0.75. Inlet - particle size Impinjet, or combination volume x correction factor = - moisture content scrubber system is best outlet volume or 10,000 x 0.75 - 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. 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 contaminant loading and 500 feet per minute. Dividing VOLUME CORRECTION CHART desired outlet conditions. the corrected or saturated 1000˚ 2000˚

Also, the availability of an volume by 500 yields the 1250˚ .40 1500˚ 750˚ 500˚ appropriate scrubbing overall tower cross-sectional 450˚ .35 350˚ 250˚ liquid is an important area from which the diameter 225˚ 175˚ 200˚ consideration. can be determined. .30 0/#DRY AIR 0/#DRY

Gas streams entering 2 a wet scrubber may or Example (continued): .25 7500 ft3/min = 15 ft2 may not be fully saturated, .20 however they will exit the 500 ft/min 2 2 scrubber fully saturated. Area = 15 ft = πD .15 ˚ This process of saturation 4 .10 150 results in a change in D=diameter ˚ 125 volume, temperature Diameter = 4.37 ft .05 INLET MOISTURE, #H and density. The calculated diameter The overall scrubber becomes the reference point .40 .45 .50 .55 .60 .65 .70 .75 .80 .85 .90 .95 1.00 size (diameter) is a for equipment selection. VOLUME CORRECTION FACTOR function of velocity of (Refer to specific product saturated gas through the bulletin.) scrubber shell. By knowing The approximate PARTICULATE COLLECTION EFFICIENCIES the moisture content of a particulate and/or mist 100 30' ∆P VENTURIVENTURI 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 ® ® and the inlet temperature; chart on the right. 95 2–STAGE IMPINJET the saturation temperature To determine the number GE IMPINJET 1–STA 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 EXPECTED EFFICIENCY % tion of the change in simple chart. However, for gas volume. either particulate or 85 0 1.0 2.0 3.0 4.0 5.0 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. Operating Principles droplets as well as dust or gases. Capacities 5.) Multiple stages can absorption (mass transfer) The gas passes up range from 500 to over be provided. of gases and vapors. When through the openings in 100,000 CFM. Depending 6.) No moving parts used for absorption, low the perforated plates (trays) upon application, water to maintain. outlet emissions can be which hold a bed of liquid. requirements vary from 7.) Extensive experience achieved by virtue of the The secret is in the less than 1-1/2 GPM per with many applications scrubber’s countercurrent scrubber’s design which 1,000 ACFM to a typical available. operation. The Sly uses an impingement baffle 3 GPM per 1,000 ACFM. 8.) Needs less scrubbing Impinjet Gas Scrubber is above each individual hole. Unique flexibility is fluid than most other able to reduce gaseous The tiny droplets, furnished by Impinjet scrubbers. pollutants to any desired created by the wetted Scrubbers. Made with the 9.) Can handle high concentration if a baffles, are the heart of future in mind, additional temperatures and sufficient number of plate the collection process. stages can be added to temperature stages is used. Gas velocities of 60 to existing installations to fluctuations. See data sheet for 75 feet/second through the improve efficiency to handle technical details. Cooling and holes result in thousands of tomorrow’s requirements– Condensing jets which atomize the without increasing liquid The outlet gas can be liquid into droplets on the consumption. There is no cooled to less than 5°F order of 100 microns in need to buy complete above the temperature of diameter to clean the new units. the incoming liquid. Often contaminated gas. This Benefits solvents such as alcohols, entraps the particles in the 1.) High absorption pentane, hexane, acetone, scrubbing liquid. Each jet efficiency for gases ethylene glycol, chloro- aspirates liquid from the and vapors. Experts form, etc. are recovered blanket of scrubbing fluid agree that plate towers from inert gas streams and results in a wetted have the ability to such as nitrogen or carbon target surface on the baffle remove gaseous pollu- dioxide. Chilled solvent is which is located just above tants to any desired used as direct contact the point of maximum concentration if a suf- condensing liquid and velocity (vena contracta). ficient number of removes the heat from the In operation, the plates are used. This gas stream as it gains heat. scrubber is highly means high mass Scrubbers also recover pluggage-resistant. The transfer rates can be waste heat. Heat from continuous violent achieved. dryers and other processes agitation of the blanket of 2.) 98+% collection that would normally be scrubbing fluid prevents efficiency for particles exhausted can be used to settling of particles and 5 microns in size heat water being fed to the flushes them away. or larger. scrubber almost to the wet 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. (Each hole has an individual impingement surface.) Minute liquid droplets are formed which entrap suspended matter in gas. Particulate carrying droplets mix with water flowing across baffles for ultimate disposal through the drain. Cleaned gas passes through the mist eliminator for return to process or atmosphere.

1.) Scrubber Outlet 2.) Fixed Blade Mist Eliminator - assures droplet-free air to process or atmosphere. 3.) Impingement Baffle Plates - 5.) Liquid Supply and Weir create interaction of (dam) - adjustable weir gas stream and liquid. provides uniform liquid Additional plates (trays, flow to plates. stages) provide increased 6.) Spray Section - for efficiency. cooling and entrapment 4.) Plate Discharge and Seal of larger particles. Drain - directs slurry to Spray washes under bottom of scrubber for side of plate and walls removal. Non-clogging seal to prevent material prevents short circuiting build-up. Sprays are of gas. non-clogging. 7.) Gas Inlet

3 Venturi Scrubbers Collect Ultrafine Particles and Mists

The Venturi Scrubber energy costs is an Benefits Operating Principles uses the differential adjustable pressure drop This Sly scrubbing The incoming gas is between high velocity provision and energy system brings together accelerated to a high gases and free-flowing regain feature which virtually all the features velocity at the scrubber’s water to create droplets combine to reduce power you should insist upon for throat where it comes into which entrap contami- consumption and your application: contact with the scrubbing nants, hold them in operating costs. 1.) Simple, easily adjust- liquid. The liquid is suspension and deliver The Sly Venturi able throat permits atomized into fine droplets them as a highly concen- Scrubber serves industry in setting pressure for which entrap the particu- trated slurry. The Sly several ways. It removes maximum efficiency. late with high collection Venturi Scrubber offers pollutants present in Can be fine-tuned to efficiency. more advantages in process gas streams. This application while Downstream from the separating and recovering includes removing scrubber is running. throat, the cleaned gas liquid mists and ultra-fine hazardous and nuisance Throat damper blades decelerates and the particulate than other gas dusts, fumes and mists are readily replaceable. particulate-laden droplets cleaning methods. from stack gases. Cleaning 2.) Variable-spin damper in collide and agglomerate. Simple in design, yet process gas streams to separator maintains The large, heavy, agglom- highly efficient, this Sly remove oils, dusts and proper velocity for erated droplets are driven Venturi Scrubber incorpo- other particulate, this collection of fine into the flooded elbow for rates features calculated scrubber offers industry an droplets. easy disposal. Droplets too to maximize collection opportunity to recycle 3.) Flooded elbow provides small for collection at the efficiency while minimiz- these gases as fuels or a wetted surface for flooded elbow are collected ing operating and process raw materials. collection of large in the separator to maintenance costs. Finally, the Sly Venturi agglomerated liquid complete the cleaning They range from a non- Scrubber makes it possible droplets. Also serves as operation. plugging, trouble-free to reclaim valuable a barrier to eliminate Pressure drop across method of introducing materials which can result equipment wear. Drains the venturi throat is a scrubbing liquid and a in significant process directly into separator measure of the energy simple, easily-adjusted savings. sump. needed to atomize the throat for optimizing Sly Inc., with over 134 4.) Removable scrubbing scrubbing liquid and to efficiency, to a flooded years of service to industry, liquid piping - no perform the cleaning elbow arrangement that offers complete air nozzles to wear or plug. operation. The higher the collects agglomerated pollution control services. 5.) Access door permits pressure drop, the higher particulate while providing We begin with an applica- inspection of flooded the collection efficiency. an abrasion-resistant tion survey, engineering elbow and spin damper. The Sly Venturi offers barrier to deter scrubber recommendations, 6.) Simple open design has the most efficient design wear. Extremely important fabrication, and end with low potential for build- for putting pressure drop in these days of rising factory assembly of a up and pluggage. to work. Its adjustable scrubbing system to 7.) Temperature and throat feature optimizes provide a satisfactory corrosion resistant scrubbing efficiency by solution to your gas construction is maintaining just the right scrubbing problem. available. pressure drop. This, 8.) Can employ a high combined with the unit’s concentration slurry as energy regain section, scrubbing liquid. significantly reduces power consumption and operating costs. See data sheet for technical details.

4 Flooded inlet eliminates wet/dry interface build-up problems.

Adjustable Throat Removable piping distributes Simple, easily-adjusted throat water without using nozzles. optimizes efficiency. Operates manually–automatic control is Separator collects ultrafine droplets too offered as an optional extra. small for impingement collection in Wetted surfaces flooded elbow. eliminate wet/dry interface build-up. Tangential outlet minimizes pressure drop.

High relative Throat adjustment. velocity maximizes Water atomization and capture of particle impaction. gas stream pollutants.

Energy regain Shielded water section reduces power inlet prevents consumption. re-entrainment of liquid in gas stream.

Clean out door.

Flooded elbow collects agglomerated, particle carrying droplets and functions as an abrasion deterrent. Access door permits inspection of flooded elbow, shielded inlet and variable spin damper.

Damper in fully open position.

Variable Spin Damper is manually adjusted to control spin velocity. Proper adjustment maintains the spin velocity necessary to efficiently Damper partially closed to increase spin velocity. collect entrained liquid droplets.

5 Eductor Venturi Scrubbers

Eductor scrubbers are Eductors are easily designed to remove soluble staged with other collection gases and particulate by devices such as impinge- inducing a gas flow using ment plate scrubbers, high pressure liquid focused packed towers or additional into a venturi throat. eductor scrubbers. Additionally, eductor scrubbers can be used for direct-contact condensa- tion. A high liquid flow rate makes the Sly eductor particularly appropriate for collection of sticky and/or gummy particulate, as well as gases which decompose upon contact with water, such as SiCl4 and H2SiF6.

6 Sly Scrubbers at Work

Gas Scrubber Removes Hazardous Vapors — An Impinjet ®gas scrubber has been employed by a major producer of industrial chemicals to remove hazardous (noxious) vapors.The scrubber vents both bottle filling and dry bulk filling areas at the company, which produces hydrochloric, sulfuric and nitric acid as well as formaldehyde and ammonia. Scrubber Cleans and Absorbs Acid Gases and Particulate From Medical Waste Incinerator — An Impinjet ®wet gas scrubber is used by this company to clean The system handles 2,500 CFM. Efficiencies exceeding 95% are reported.The high exhaust gases from its on-site medical waste incinerator. efficiency of the scrubbing system is due to the unique design of the impingement baffle plates, which cause the contaminated air to mix intimately with the 7258 CFM of gas at 1800°F from a 100 lb. per hour incinerator is handled by this skid- scrubbing solution. mounted wet gas scrubber. A proven impingement design creates turbulent conditions to insure intimate contact between particulates and acid gases for thorough removal of pollutants, including HCL.

Eductor Venturi/Packed Tower Combination Removes Particulate and Scrubber Collects SO2 And Particulate At Reprocessor of Petroleum Absorbs Alcohol Vapors — A combined eductor/packed tower collector that Catalysts — An Impinjet ®gas scrubber is used by this recycler of spent petroleum removes solid particulate and absorbs alcohol has been successfully employed by this and chemical refining catalysts to clean flue gas from its ovens. major specialty chemical producer. Carbon and sulfur from used catalysts is thermally oxidized by the company, creating The equipment vents a variety of process equipment. The eductor venturi induces the sulfur dioxide and particulates, primarily carbon. Previously, a packed tower style gas flow using a high pressure and volume of recirculated water focused into the throat scrubber was used to clean the resulting flue gas. Unfortunately, the packed tower of the venturi. Particulate matter is removed in venturi. tended to channel, as well as not collect particulate. The Sly scrubber uses a proven After the eductor, a packed tower scrubber with an extended packed section removes impingement design, which creates turbulent conditions to insure intimate contact alcohol vapors by counter-current contact with a once through flow of fresh water. between the gas contaminants and the scrubbing solution. This results in efficient The equipment is skid-mounted, stainless steel construction, designed for 500 CFM. removal of both particulate and SO2.

7 Sly’s Approach to Air Pollution Control: • conservative design • flexible engineering • controlled manufacturing • comprehensive field services

Many companies make “We believe in fitting “We build our own problems should they air pollution control the equipment to the equipment...for some arise at your facility. This equipment, but none have customer’s needs, very good reasons.” commitment to total been doing it as long as Sly. not the customer Part of the reason Sly customer support helps More than a century to the equipment’s can custom-make a guarantee superior value capabilities.” has passed since our collector for you while for your investment. original patent for cloth Unlike many equip- keeping a competitive price ment suppliers, we refuse “We’re a private dust filters. Over the years, is just that: we are the company, and intend we’ve learned plenty to mass-produce product manufacturer. Unlike the to stay that way.” about the application and and then hope for a good majority of our competi- The corporate fabrication of dust fit. We have maintained tors, we don’t job out our restructurings and short collectors and scrubbers. flexibility in our engineer- production. We do our term goals of today’s Here are the main points: ing techniques which own engineering, metal business scene aren’t for permits us to manufacture fabrication, painting, us. Sly is owned and “In the pollution each order to fit the task at control business, assembly, quality control, operated by descendants hand, while maintaining conservative and laboratory R&D. This of the founding family. a price to you that is application of way we control every step We are in the business for comparable to mass- technology is best.” of the process, allowing us the long run, and will produced equipment. Equipment misappli- great flexibility to build the maintain the professional- In many cases it costs no cation has no place in the best collector or scrubber ism and continuity more to get the very best pollution control business. for your individual needs. required to contribute to equipment for the job. Not only is improper We have a strong commit- the long term success of This approach earns us equipment apt to fall short ment to shipping dates and your business. the respect and repeat of collection requirements, routinely guarantee ship business of many sophisti- it is oftentimes more dates when requested. cated buyers of pollution expensive to operate than control equipment. These “Our obligation to the the proper machinery. For people, many of whom buy customer doesn’t end example, incorrect sizing when the equipment dozens of collectors or and improper media is shipped.” scrubbers every few years, choice can easily lead to Sly’s staff engineers have always represented a excessive maintenance and can promptly assist you in large portion of our costly downtime. When troubleshooting or with customer base. you deal with Sly, we have other field service your best long term interests in mind.

8 8300 Dow Circle Strongsville, OH 44136 1-800-334-2957 (440) 891-3200 Fax: (440) 891-3210 Web: www.slyinc.com E-mail: [email protected]