phase separation technology cross-flow scrubber design · cross-flow scrubber design ... is a...

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Email: [email protected]

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Cross-Flow Scrubber Design James Eldridge, Senior Applications Engineer, Kimre Inc; Miami FL, USA

Background; Cross (Horizontal) Flow vs. Counter-Current-Flow:

Cross-flow or, Horizontal-flow scrubber design is almost never mentioned in chemical engineering literature. Textbooks

(1) used at universities for future engineers, undergraduate as well as graduate level students,

invariably only discuss counter-current vertical scrubber tower design. Likewise, professional reference texts (2)

generally provide little or no mention of horizontal cross-flow designs. And, when cross-flow design is mentioned, the discussion is usually very brief. The normal design discussion usually revolves around a packed tower and packing choices in consideration of improved gas to liquid surface contact, where the actual mass transfer of gaseous pollutant to liquid phase takes place. In nearly all cases, the packing discussion assumes that a random dump-packing product (saddles, rings, etc.) will be chosen to fill the tower. Thus a brief review of wet scrubber, counter-current packed tower design, is appropriate.

Basic Scrubber Design:

To design a typical scrubber tower, in this instance using an example of a wet scrubber for absorption of a gaseous pollutant into a liquid stream, the following criteria are required:

Total Air Flow: (Am3/hr; Nm

3/hr or ACFM; SCFM)

Air and Liquid Temperature: (ºC or ºF)

Identity of Pollutant: (i.e., SO2; NH3; H2S; ClO2; etc.)

Pollutant Concentration: (ppmv; % by mass; etc.)

Desired Removal Efficiency: (% removal, ppm/unit volume, mg/unit mass, or volume)

Using the above data, the design engineer must then decide what type of scrubbing is required. An aqueous solution may need to be pH adjusted, have an oxidizing agent added, as well as other possible factors or adjustments, as they may apply. For example, as seen for odor problems at a wastewater treatment plant, multiple pollutants such as NH3 and H2S are often present. In order to target the individual pollutants, two stages or possibly more, of wet scrubbing may be required to compensate for conflicting chemistries. Ammonia is usually first scrubbed with an acid solution, then the hydrogen sulfide is scrubbed with an alkali solution, and an added oxidizing agent may also be required.

After choosing the correct chemistry or chemistries, the design engineer must then proceed to „crunch‟ the numbers. The calculation exercise will determine:

G and L: Gas and Liquid Flow Ratios (lb/hr-ft2 or kg/hr-m

2)

These values, with some manipulation, will then be used to determine the required face area of the tower. Normally the sizing will be rounded up to the next available standard tower size, either round, square, or rectangular; in English or metric units.

The total height of packing in the tower is determined by:

Ht = Nog x Hog

where: Nog = Number of Gas Transfer Units

and; Hog = Height of Gas Transfer Unit

PHASE SEPARATION TECHNOLOGY

AIChE Annual International Phosphate Fertilizer

& Sulfuric Acid Technology Conference

June 6 - 7, 2008 Sheraton Sand Key Resort - Clearwater Beach, FL





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(Note; for an air stripper column, where the mass transfer is from liquid to gas, not from gas to liquid

as in the above, the terms would substitute „Hol„ for liquid film controlled mass transfer.)

Commercially available packing(s) have various values of Hog. The packing supplier provides these values

which are often derived empirically. This value is an inverse relationship, the smaller the reported value (in feet or meters) indicates a higher claimed packing efficiency. Stated another way: if less depth of packing is required to achieve the same mass transfer efficiency, comparing one packing product to another, the

product with the lower Hog value is seen as the more attractive packing. Selection of the lower value would

facilitate a lower total packing depth, necessary to achieve the targeted performance and efficiency.

The choice of packing is not always driven by which packing can be identified as being the most efficient for a given service. Generally, packing that is smaller in size, (i.e. a 1-inch size packing vs. a 3-inch sized

product) will have the lower reported value of Hog. However, pricing for smaller sized packing generally

makes for a higher total packing cost, as more pieces of the packing are required to fill a tower‟s given unit volume (ft

3 or m

3). Smaller sized packing also tends to have greater pressure drop per unit depth (ΔP/ft or

ΔP/m) vs. larger sized packing. Smaller packing choice is usually a cost adder, in terms of the initial purchase of the packing product as well as that for the fan size and horsepower requirements, as determined for that needed to motivate the gas through the scrubber system‟s predetermined minimum face flow area.

As a result, the design engineer must arrive at an initial scrubber tower design that:

Achieves the required scrubbing efficiency.

Can be manufactured economically through the selection of a „standard‟ tower size.

Or, if a non-standard fabricated tower must be used, the engineer must consider whether the tower is a practical size that can be locally fabricated, or can be shipped at a total reasonable cost (if it were fabricated some distance from the project site).

Operates at a predicted and reasonable (calculated and actual) pressure drop. The pressure drop correlates directly with the cost of the scrubber fan and the operating costs.

The system fan should not be excessively expensive, and should have a predictable long-term lower operating cost.

(For very large projects, a complete tower shipment is often not possible. This consideration is beyond the scope of this discussion, except to note that it is an additional cost adder, or it may be prohibitively expensive; as on-site fabrication or „panelized‟ construction may be required.)

The design engineer must perform iterative calculations, until all of the required criteria are satisfied.

Gas Phase Absorption; Mass Transfer vs. Particulate Capture:

Another very important consideration:

When an engineer derives a process design for a counter-current, packed-vertical-bed, wet scrubber; it is usually assumed that the species to be absorbed in the tower (e.g., H2S, ClO2, HCl, etc.) is gaseous.

For the above just cited examples; hydrogen sulfide and chlorine dioxide can be assumed to be totally gas phase. However, hydrochloric acid is notorious for forming extremely fine fogs or aerosols. Also called mist, the aerosols are typically composed of very small droplets, typically ~2-μm droplet diameter. These small and lightweight particles, when carried along in the gas phase of a packed bed scrubber simply zigzag past the packing. Consequently, if the fine mists are not effectively captured in the tower‟s top mist eliminator, they will exit the scrubber stack as a white fog. This occurs, despite the scrubber typically performing at 99% or greater efficiency for the gas phase HCl absorption, as the remaining presence of the fine aerosol HCl passes through the tower, ultimately forming the distinctive white plume.





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In addition to acid gases, the problem of aerosol formation is a common problem in the manufacture of fertilizers. Typically in a scrubber processing phosphates, fluorine and silicon are common contaminants. HF and SiF4 are usually present as gaseous contaminants that must be removed before discharge to the atmosphere. However, HF like HCl, as well as H2SiF6 (formed when SiF4 reacts with water) form aerosols composed of very fine particles, typically 1 to 6-μm in size. Examples of poor performance of air pollution control scrubbers at NPK plants are unfortunately all too common due to reliance upon gas phase mass transfer designs which ignore aerosols. Cross flow

scrubbers, using the Kimre, Inc. KON-TANE®

structured mesh type packing and B-GON®

structured mesh

mist eliminators, have been shown to be very reliable in this type of service (3)

.

Cross Flow Design Advantages vs. Counter Current Design:

The mathematics discussed above may be arcane; however the principles involved in counter-current flow, normally liquid down and gas up, are straightforward. Thus, over the years, the briefly discussed design model has become very well established within the chemical engineering profession. Cross-flow scrubbing, normally with the gas flowing horizontally with the liquid flowing perpendicularly downwards across the gas flow, does not present a simple and easily derived mathematical model. Indeed, the mathematics of a cross flow scrubber are so convoluted, mathematical solutions have essentially been ignored by academics and others for many years. It is very important to note that even though the counter current pattern is considered to be much more mathematically straightforward, than the cross-flow pattern as

previously mentioned, values of Hog are almost always empirically determined.

However, cross-flow scrubbers are quite common. A Google Internet search using the simple terms

“horizontal scrubbers” returns a plethora of web sites. The University of Arizona chemical engineering

department reports that horizontal, cross-flow scrubbers are the most common type of scrubber found in the semiconductor industry

(4).This itself emphasizes the distinct advantages of the cross-flow versus the

counter-current (vertical) flow design:

It is very simple to accommodate multiple stages within a cross-flow scrubber. For the prior cited odor-control scrubbing example (in which ammonia is first scrubbed, then hydrogen sulfide at an alkaline pH) a traditional counter-current system would usually require two individual towers in series. Hydrogen sulfide odor problems are usually treated in two scrubbing stages: first a caustic-only scrub of the smelly gas at pH ~12, then a second stage scrub of the hydrogen sulfide at pH ~9 with an added oxidizing agent. This is usually done to conserve chemicals; typically using sodium hypochlorite (NaOCl) as an oxidizing agent is expensive. The 1

st stage promotes solubility for approximately 80% of the H2S present.

The 2nd

stage, before the gas being treated is discharged, oxidizes the remaining H2S to sulfate, at a very high efficiency. The 2

nd stage scrubbing NaOCl solution is returned to the sump of the 1

st stage

tower, assuring that 100% of the expensive oxidizing agent is ultimately consumed. Figure 1 shows a typical odor control system common to many large wastewater treatment plants in the USA.

A single, multi-stage vertical tower is possible, but in practice it is very difficult to fabricate. Such a single tower would also challenge the height of the tree line behind the scrubbers shown in Figure 1. Even if an OEM firm did succeed in fabricating such a multi-stage tower which isolated the chemistry of both stages, coping with any slight corrosion (or other long-term vessel fatigue over the life of the tower) would result in contamination of the lower stage by the upper stage chemicals.

The above noted problems do not exist in a cross-flow scrubber. A scrubber with two, three or any number of stages, all using different chemistries, is very practical to design and fabricate. With high efficiency mist capture between the separate stages, any cross contamination of the various chemistries is easily prevented.





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Figure 1 - Two Stage, Dual Train Odor Control Wet Scrubbers (Photo courtesy of Hampton Roads Sanitation District, York River WWTP)

Design & Configuration details: 43,000 cfm, 12 ft Diameter Towers, 4.5 gpm/ft

2 Liquid Flux, 10 ft packed beds

Total ΔP ~1 in WC Inlet H2S ~53 ppmv; Outlet H2S ~0.01 ppmv

1st Stage Caustic Only Scrub at pH of 12

2nd

Stage Caustic + NaOCl Scrub, pH of 9.5, and ORP of -600 mV

A cross flow scrubber has a much lower profile compared to a counter-flow tower.

The low profile can be very important in urban or other locations. In most instances only a cross-flow is practical when a scrubber must be located on a rooftop, Figure 2 indicates a typical urban industrial roof top installation.

Figure 2 - Two views of roof top, cross-flow VOC scrubber. (Photo courtesy of MAC Corp., Lowell MA)





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When designing a cross-flow scrubber, it is often very practical to fabricate a skid-mounted unit. Such a design permits shop testing before shipment and provides the customer

(5) delivery of a fully tested,

ready-to-install, ready to operate pollution control system. System startup problems are by large eliminated.

Cross-flow scrubbers provide an extremely simple system layout (6)

: pumps, valves and control panel are easily side mounted on the cross-flow system with access doors to each stage available on the opposite side. Operational control and system maintenance, even for multi-stage systems, is straightforward.

Cross-flow scrubbers are also very practical at very low L/G ratios. This can be important if blowdown (i.e., spent scrubbing solution) of the scrubber must be maintained within a close specific concentration range. For example, a hydrochloric acid gas scrubber blowdown target may be 16% salt. The needed counter-current scrubber controls can be very complicated, although relatively simple for a cross-flow.

Upset and/or variable (non-steady-state) operations are much more easily managed by a cross-flow scrubber vs. a counter-flow design. Horizontal cross-flow scrubbers are less sensitive to poor water distribution vs. counter-flow. Total media coverage/wetting by the liquid inlet nozzles is important in a cross-flow scrubber. However, even when a small area of the packing is not wetted, the gravity down-flow of scrubbing liquor will still wet the entire media. In contrast, when a counter-flow scrubber spray nozzle malfunctions, the resultant “dead area” of the packing face will tend to propagate deep into the media bed, causing a severe malfunction.

Cross-Flow Scrubber Efficiency vs. Counter-Current-Flow:

As noted, it is almost a universal concept amongst chemical engineers that a cross-flow scrubber will have reduced efficiency vs. a counter-current-flow scrubber for a given service. And, this lower efficiency can, at least in part, be overcome by sizing the cross flow scrubber larger than the counter-current-flow design. This has been held to be an obviously higher cost factor for a given project. Thus a common erroneous design technique for the design of cross-flow scrubbers is simply to use the available counter-current design and then apply a larger than normal safety factor

(7).

The concept of safety factor is an interesting one to explore, in the context of this discussion.

All design engineers tend to apply some factor to the calculation of packed bed depth, be it 10%, 20% or higher. This safety factor is intended to account for field conditions which, in almost all cases, are not ideal. An important condition that is assumed in all design calculations of a wet scrubber is achieving uniform distribution of liquid and gas within the vertical scrubber tower, commonly referred to as „plug flow‟. Even with perfectly designed and maintained liquid and gas inlets, it is obvious that perfect distribution of the two phases, hence perfect contact between the two phases, should not be assumed to exist in an operating wet scrubber. Therefore, if a design engineer determines that the packing depth required for a given service to be 10 ft (~3 m), the actual packed depth recommended to the system OEM will probably be 12 ft, representing a 20% safety factor. And in the case of a cross-flow scrubber, the design engineer might well boost this to 14 or 15 ft depth of packing (adding respectively 40 and 50% safety factors)

(7).

Fthenakis(8)

presented one of the few detailed studies of efficiency of cross-flow vs. counter-current-flow scrubbers. Interestingly, the results of that study indicated that the Hog of spherically shaped packing material was not significantly different in either flow regime. However, the Hog of saddles was found to be 50% greater in a cross-flow vs. counter-current-flow scrubber. The author presents a plausible theory that packing of certain shapes could confer greater efficiency in cross-flow than they provide in counter-flow regimes. The author predicted that cylindrical rings would perform more efficiently in vertical-flow than horizontal-flow.

The work of Fthenakis(8)

is supported by the results published by a University of Southern Queensland(9)

student. Although only an undergraduate level study, the paper confirms that some packing media, in this

case LANPAC®, can be found to have an identical Hog value in both cross and counter-current-flow.





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However, No.2 Type R Tellerette® packing was found to have a 10% greater Hog value in cross-flow than in

counter-current-flow. Therefore, the packing geometry did appear to degrade plug flow in some instances, while not in others. So, it could be seen, that with the correct choice of packing, it appears possible to build an equally efficient cross-flow scrubber of the same (or smaller) size as the counter-current scrubber.

However, another consideration in scrubbers filled with random dumped packing is that this packing tends to settle. Suppliers of such products routinely recommend that 3% to 10% extra product be ordered to allow for a later „top up‟, compensating for the „settling‟. This is of particular importance when discussing a cross-flow scrubber employing dumped packing material. Any settling of the packed bed will create a gap between the top of the packed bed and the roof of the scrubber. Preferential gas „bypass‟ flow through this open space will degrade the performance of the scrubber. This might well have happened in the undergraduate research conducted at the University of Southern Queensland. If the Tellerette

® bed happened to settle faster, or was

not properly installed in the first place, this would create a plausible theory as to why the performance of the cross-flow scrubber was observed to be inferior to the counter-current-flow scrubber with the same packing. Kimre, Inc. holds a solution to the settling problem of packed bed scrubbers. As explained below, Kimre‟s structured packing has provided high efficiency scrubbing in horizontal cross-flow scrubbers, for decades.

KIMRE SXFTM Semi-Cross-Flow Scrubber Design Using KON-TANE® Scrubber and Tower Packing

Kimre, Inc. of Miami, Florida has been designing SXFTM

Semi-Cross-Flow Scrubbers of a very unique design for over 35 years. (See the sketch in Figure 3) These scrubbers are installed and are operating at high efficiencies, removing fine particulate, dust, and other contaminants such as HF, H2Cr2O7, SOX and NH3 in a wide variety of industries. Kimre

TM Technology excels for the very demanding service conditions, such as in

sulfuric acid plants, NPK fertilizer facilities, steel pickling lines, incinerators, hard chrome plating facilities, and other applications too numerous to list (Refer to Table 1). Removal efficiencies of 99% and higher are routinely achieved in these semi-cross-flow scrubbers.

As opposed to a standard cross-flow design, where the scrubbing liquor is sprayed onto the horizontal face of the packing, the Kimre SXF

TM scrubber employs concurrent conditioning spays. This provides some of the

impetus to improve efficiency, by lowering solids level in the gas stream being treated, in addition to cooling and saturating the gas flow, followed by concurrent spray of the scrubbing liquor onto the face of the

KON-TANE®

stage (or stages). In some instances, a conditioning spray is also introduced on the

downstream side. The scrubbing liquor then flows down through the KON-TANE® media, crossing the

horizontal gas flow, discharging into the bottom sump(s) of the scrubber. Lastly, carry-over mist is captured

in a B-GON®

stage. This proven design strategy is shown in Figure 3, below.

Figure 3 - Typical SXFTM

Scrubber Design

(Three KON-TANE®

Conditioning Stages and Sprays, followed by One B-GON®

Mist Elimination Stage.)





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Table 1 - Some SXFTM

Phosphate Processing Scrubber Applications

Use of KON-TANE®

for assurance of: non-Clogging Flow; No Gas Bypass or Short Circuits.

The use of random dumped packing in a cross flow scrubber can result in compromised efficiency due to the

settling of the packing. KON-TANE®

Tower Packing, produced by Kimre, Inc. of Miami FL has solved the

settling problem. Kimre KON-TANE®

Tower Packing additionally offers numerous operational advantages.

KON-TANE®

is custom-designed structured media, supplied as a multi-layered pad, usually round or square,

although almost any shape or configuration is possible. The „rectangular‟ or „square‟ configuration is ideally

suited to cross-flow design. As seen in Figure 4, the mono-filaments of Kimre KON-TANE®

, and Kimre

B-GON®

products, are about 93% perpendicular to the direction of gas flow, a result of the unique

interwoven structure of the Kimre media. With void fractions commonly ranging from 94% to 97%, the pressure drop through this tower packing is very low, and very predictably calculated. The structured media elements perpendicular to the gas flow assure that maximum renewal of liquid and gas phase surfaces occurs, which in turn yields maximum mass transfer efficiency.

KON-TANE

® Structured Media. Figure 4 Kimre Unique Interwoven Structure.

Kimre, Inc.

KON-TANE®

& B-GON®

MONO-FILAMENT STRUCTURE





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Individual Kimre KON-TANE®

pads can be framed as large as 6 ft wide (1829 mm) by 10 ft high (3048 mm).

Multiple KON-TANE®

pads are used for large vessel configurations. Framed KON-TANE®

media is shown

on the left in Figure 5. One of Kimre‟s two proprietary types of media frames is seen on the right in Figure 5. The two proprietary mounts are BATTEN BAR

TM and PANTS HANGER

TM frames. Both designs assure that

no gas bypass occurs, while providing for easy media access and removal for cleaning. The minimal pressure drop across the scrubber (typically ~1” WC) is sufficient to assure that a seal is formed between the media frame and the scrubber internals. The Kimre SXF™ cross-flow scrubber internal design along with the proprietary media frames provide for easy media installation (and removal). The uniformity of the

KON-TANE®

media also ensures uniform plug flow throughout the entire scrubbing section, thus providing a

high efficiency that may even exceed that of a counter current scrubber of equal length. Figure 5 shows a PANTS-HANGER

TM installation cassette on the left and a BATTEN BAR

TM frame on the right.

Figure 5

KON-TANE® Media in Schematic of BATTEN BAR

TM Support

PANTS-HANGERTM

frame module

Figure 6

KON-TANETM

media installation. Example of BATTEN BARTM

support frame.





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Kimre KON-TANE®

scrubber media and B-GON®

mist eliminator (ME) media assemblies are custom made

to accommodate almost any required shape. Figure 7 shows several B-GON®

mist eliminator (ME) pad

shapes and materials; round PVDF ME pad (left) and a rectangular PP ME pad for the vessel presented on the right. Figure 7, right, is an example where a cross-flow mist capture vessel is much more suited for a rooftop installation, than for a vertical tower. Examples of other possible shapes and configurations are seen in Figure 8.

Figure 7

Round B-GON®

PVDF mist eliminator media; Rectangular shaped mist capture system.

Figure 8 Additional examples of Kimre media cut and mounted to special shapes and needs.





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Another advantage of the Kimre SXF

TM Semi-Cross-Flow Scrubbers is that the media can usually be

exchanged quickly „on-line‟ for maintenance or replacement; thus preventing costly down time. In a multi-

stage semi-cross-flow scrubber, one stage of KON-TANE®

media is often removed as the scrubber

continues to operate within required emission limits (10)

. A spare stage can be quickly inserted in place of the

removed KON-TANE®

media. This type of maintenance can be accomplished within a few minutes, and the

removed KON-TANE®

media cassette can then be serviced at the operators‟ convenience.

Cross Flow Scrubber Design Example: Typical design parameters for a SXF

TM scrubber are:

NTU per stage: 3+; empirically derived (10)

Superficial Gas Velocity: 400 - 500 fpm (~2.00 - 2.54 mps) Liquid Flux per Stage: 4 gpm/ft

2 (10 m

3/hr/m

2)

Pressure Drop: 3 in WC or less (76 mm H2O)

Example; Odor Control Scrubber, as presented in Figure 1: Air Flow, Normal: 43,000 cfm Air Flow, Future Capacity Increase: 54,000 cfm Number of Vessels: 1 (per train)

Vessel Face Area: 108 ft2 comprised of KON-TANE

® and B-GON

®

(double-width panels, side by side, each 6‟ by 9‟)

Approximate Vessel Size: 12.5‟ Wide by 9.5‟ High by 15‟ Long

Number of KON-TANE®

Stages: 3

Stage 1; Caustic Only Scrub; pH = 12 in sump Stages 2 and 3; Caustic with Oxidizing Agent Scrub, with common sump at pH = 9.5, ORP ~ -600 mV, and, overflow into the Stage 1 sump. Stage 4; One stage of B-GON

® Mist Eliminator

Pressure Drop: < 2 inches of Water Column

Note: There is no requirement for mist capture after Stage 1 in this application. This would NOT be true in a single, vertical tower with two stages; due to the oxidizing chemistry of the 2

nd stage which must be isolated

from the 1st stage. The Kimre SXF™ single horizontal cross-flow vessel design would be the only possible

economical, lower cost, higher assured performance alternative with which to accomplish the chemical conservation goal of the cited two-stage vertical tower design, while yielding lower maintenance and operational costs.

Review: Cross-Flow Scrubber Advantages:

Cross-flow scrubbers can provide equal or even greater efficiency than counter-current scrubbers of equal length. A flue gas desulfurization study reported an operating efficiency so high in a cross-flow scrubber as to question the accuracy of the instrumentation used

(11). Cross-flow scrubbers present a cost advantage in

many applications. Without question, a cross-flow arrangement will be much more convenient than a vertical-counter-current scrubber. (See the tabulation below.)





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Some other advantages of Kimre, Inc. SXF™ cross-flow scrubbers include:

Problem Vertical Counter Current Kimre SXFTM Cross Flow

Sensitivity to Component Failure Dramatic/Adverse Minimal

Upset Conditions Dramatic/Adverse Minimal

Adaptability Difficult to Impossible Simple

Maintenance All or none Packing Removal Easy: Removal of Media; (On-line maintenance One Stage, or Multi-Stages is never possible) On-line Maintenance (No Shut Downs required)

Multi-functions Difficult Easy

Operating Expense Higher Lower

Efficiency Equal Superior / Equal

Authors and Contacts: James Eldridge (Author & Presenter), Senior Applications Engineer, [email protected] Marilia DaSilva, Applications Engineer, [email protected] Dr. Diana Marmorstein, Applications Engineer, [email protected] Jose Velasquez, Applications Engineer, [email protected] Frederick Mueller, (Editor) Sales & Marketing Manager, [email protected]

Trademark Acknowledgements:

SXFTM

; AEROSEP®

, KON-TANE®

; B-GON®

; PANTS-HANGERTM

; BATTEN BARTM

;

Kimre™ Technology are registered trademarks of Kimre, Inc. Miami Florida, USA

LANPAC®

is a registered trademark of Lantec Products, Inc.

Tellerette®

is a registered trademark of Ceilcote APC, Inc.

References: (1)

McCabe et al.; Unit Operations of Chemical Engineering 5th Ed., McGraw Hill, 1993

(2) L.K. Wang, ed., Air Pollution Control Engineering, Volume 1; Humana Press, 2004

(3) G. C. Pedersen and W.M. Schott, Cross-Flow Mesh vs. Counter-Flow Dumped Scrubbers: A

Comparison, ACHEMA International Meeting on Chemical Engineering and Biotechnology, June 1997.

(4) SRC/SEMATECH Engineering Research Center for Benign Semiconductor Manufacture,

Dept. of Chemical Engineering, University of Arizona, Tucson AZ, www.erc.arizona.edu (5)

Case Study, Record size cross flow scrubber installed at B.C. Kraft mill,

www.fabricatedplastics.com (6)

Ron Patterson and Andrew Bartocci, Wet Scrubber Design for Brick Kiln Applications, Pollution Engineering, May 1, 2005. (7)

Personal experience of the author (8)

Vasilis M. Fthenakis, Cross-Flow versus Counter-Current Flow Packed Bed Scrubbers: A Mathematical Analysis, AIChE Spring National Meeting, New Orleans, LA, 1996 (9)

Yap Lee Jiuan, Evaluation of Wet Scrubber Systems; BA Mechanical Engineering Thesis,

University of Southern Queensland, Brisbane, Australia, www.usq.edu.au, Oct. 2005 (10)

M.J. Derenthal and W.M. Schott, Meeting the challenge of environmental control problems, Phosphorus and Potassium No. 216, pp. 38-43, July-August 1998

(11) Shattuck, D. et. al., A History of Flue Gas Desulfurization (FGD) – The Early Years,

www.ue-corp.com/news/wp-fluegas.pdf

mailto:[email protected]





http://www.erc.arizona.edu/

http://www.fabricatedplastics.com/

http://www.usq.edu.au/

http://www.ue-corp.com/news/wp-fluegas.pdf

Primary Features: Secondary Features: KIMRE™ B-GON® Media Benefits to You:

Customized Design: Ability to Custom Design for a Variety of:

Droplet Removal Efficiencies and Pressure Drops,

Wide Range of Smallest Filament Diameters Best Collection Efficiency at Small Diameters

Monofilament Diameters: Largest Filament Diameters Best Pluggage Resistance

Highest Flow Capacity (When Combined with High Void Fraction),

Highest Filament Resiliency and Strength.

Provides the Best Customizable Capacity Designs for:

Dust Loading, Liquid Loading, Particle Size & Pressure Drop.

Individual Layers of Media: Composite Construction Provides for a Wide Range of Conditions:

Multiple Functions in One Composite Pad.

Composite Pad is Used to Complement other Technologies.

Highest Removal Efficiency Per Pressure Drop,

Integral, Uniform 3-D Structure: Highest Removal Efficiency Per Length of Fiber

Lowest Potential for Pluggage

Supports higher mechanical Loads than ANY Other Mesh

Integral, Uniform 3-D Structure: Self Supporting and Resilient NO Need for Support Rods thru the Media which Causes Bypassing.

Cleanable and Re-usable

Integral, Uniform 3-D Structure: Extraordinary Strength High Fiber Tensile Strength Provides the Ability for Large

Pads to Withstand Higher Degrees of Loadings and Stress.

Integral, Uniform 3-D Structure: Built-in Drain Points Accommodates Large Liquid Loadings and Higher Velocities.

Best Design Program Accurate Prediction of Efficiency, Flow Capacity & Pressure Drop

Provides Easer Installation and Maintenance.

Integral, Uniform 3-D Structure: Flexibility Problems and Repairs are Readily Remedied by use of Edge

Wrapping Media (Quick and Economical Repairs).

Retains Shape and Thickness

Integral, Uniform 3-D Structure: Withstands Mechanical Damage Can Handle High Pressure Washing.

Cleanable by Crushing Media to Remove Scale.

Non-Isotropic Flow Properties: Gas Flow Spreads-out within the Media which Evens the Flow

Integral, Uniform 3-D Structure: Flow Resistance Inside the Across the Media, Providing Flow Stability, Complementing other

Media is Lower than the Flow Products such as Chevrons, Making for Excellent Operation

Resistance Through the Media for Carbon Bed Supports, as well in Cyclone Separators.

Integral, Uniform 3-D Structure: Wide Variety of Void Fractions: Provides for a Wide Range of Liquid Loadings.

60 to 97% Allows use in "Plugging" services, and in High Load Bearing Conditions.

Fewer Seams are Needed virtually Eliminating the Possibility of Bypass.

Large & Wide Pieces: Fewer Component Pieces. Makes for Faster Installation.

Provides the Capability for a Variety of Shapes, including "Candles".

Large & Wide Pieces: One-Piece Construction Interleaving Allows the Construction of Huge Single Piece Pads.

Allows the "In-Place" Construction of Seamless Pads in Large Vessels.

Materials of Construction: Selected for the Process Enables a Wide Range of Chemical & Temperature Resistance

Hot Wire Edge Cutting: Very Accurate To Size" Cuts Provides the Best Fit and the Lowest Risk of By-Passing

Hot Wire Edge Cutting: Cut Edges are Always Denser Provides Less Risk for By-Passing.

than the Body of the Pad Reduces the Risk for Localized Flooding.

Proprietary Thermal Stabilization: Media is Stabilized Provides the Best Heat Stability of any Non-metallic Mesh Pad.

Provides the Composite Pad with a High Resistance to Pluggage.

Stagewise Particle Separation: Composite Pad Construction The "As-Installed" Pressure Drop Stays Consistently Lower,

in Comparison to Others.

We at KIMRE™ Engineer the Product to Satisfy the Process Needs.

We DO NOT Limit the Process to Fit the Product.

KIMRE™ Custom Engineered Solutions:

PHASE SEPARATION TECHNOLOGY

90+% of Fibers

are Perpendicular

to the Gas Flow

TM

FHM REV 3, AUG. 29, 2007

phase separation technology cross-flow scrubber design · cross-flow scrubber design ... is a...

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