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`HYDRITE EXHIBIT 1007
`(1 OF 10)
`
`

`
`MARCH 1998
`VOLUME 105,
`N0.3
`
`m
`
`~•
`:~
`
`www.~he.com
`Manufacturers
`~•;raex~, ~
`and vendors
`':
`can't just offer
`'~~~'"F~'~'"" ~
`J ~, ~~~ti: W ,~',~T~ ~ wares. They
`~ must be on the
`r =
`'.••~
`cutting edge
`• ~
`in design,
`'~~ ~ ~"~ ~ + ' "'°'
`and must test
`•+
`land optimize
`~~'` .; D'"
`~~'
`.., • :; 3 ~; ~ ~, products to
`Comer
`needs
`O' ~ ~_ ~: ..,
`
`A f filter, as shown
`at right, can
`characterize the
`size range of
`particulate matter
`that must becaptured
`byair-pollution
`control equipment
`~ .~~" ~`''fi~-.
`• • •
`Sampling of
`~ r ~~~
`~-~ '`~~ j 4~, hazardous
`~='"~ ~~ - ~G~ „ materials by means
`~4 ; ~~ ~ of an automated,
`~ ~
`~, enclosed sampler
`•% will eliminate
`~~
`of wo k rs
`, ~' -y
`
`COVER STORY
`32 The valve industry —it's
`a buyers' market
`Tighter margins and loH•er sales ~~olumes
`are forcing ~~endor mergers and acquisi-
`tions. The resulting competition is gen-
`eratingcustomer benefits pia new prod-
`uctsand impro~~ed performance
`NEWS
`~ 9 Chementator
`H?•drometallurgy route competes with
`smelting • A bidirectional pumpturbine
`• Analyze non-homogeneous particles ac-
`curately •Cheaper PCB disposal page 19
`Et}~anol route poised for commercial
`debut •New technique stabilizes en-
`zJTnes •Adding value to chicken feathers
`• Hybrid power project seeks to boost ef-
`ficiency, a~•oid emissions
`page 21
`Bacteria tacUe tough sulfur compounds •
`Online pathogen monitor • Po~~•er~density
`record for a mini gascooler •New reform-
`ingprocess gets a Uyout
`fxigr 23
`An electron beam zaps NOx and SOx •
`Alinimizr bacterial films on food-process-
`ingequipment • Flameless oxidizer dew
`Buoys gaseous and liquid pollutants •
`1'arucle characterization mo~~es from lab
`to plant
`pQ~e 25
`Predicting die impact of chemicals tin
`rn~ers • Digester goLbles hig}rsolids Nastes
`• Cut dorm sludge ~~olumes ~~ith a flash-
`and-slash routine •European Union plans
`anew R$cD program
`page 27
`U.S. DOE, EPA, FDA seek higher bud-
`ge~s •EPA: RcCorm speeds cleanup •
`EPA to case chemical-im~entory report-
`ing • UN dc~~cloping a global chemical-
`labclingstandard
`pQ~ 29
`CHEMICAL ENGINEERINC3 /MARCH 1998
`
`43 Maintaining a balance
`between work and family
`Producu~~ty increases when employers
`help workers cope with pressures off the
`job, ac well as in the workplace
`
`52 EPA issues alert on
`ammonium nitrate
`The compound, widely used as a fertil-
`izer, can support and intensify a fire,
`even in the absence of air
`6~ Chemicals: Alliances grow
`in the chiral chemicals field
`In the competition for a slice of the $14
`billion/yr business, small firmswith syn-
`thesisexperience are partnering with
`large ones that have scaleup svengths
`ENGINEERING
`37 Engineering challenge:
`Coming up with better wine
`Low-alcohol wines appeal to consumers'
`sensibilities, but not their palates. Solu-
`tions are in the works
`96 How to optimize
`dryer performance
`This second article of a two-part series fo-
`cuses on more advanced dryer controls
`that can significantly impact product
`quality and energy efiicienry
`~ 29 O&M: Sealing flowrates in
`horizontal-run pipes
`Practicalgraphs can help deteRnine if
`horizontal pipelines are running Gill of
`liquid, or if undesirable two-phase flow is
`instead occurring
`
`1 S9 Plant Notebook: Improve
`operation of BTX units
`A simulator and a data package accu-
`ratelymodel aromatics exuacuon systems
`
`ENVIRONMENT,
`HEALTH &SAFETY
`74 Feature Report Matching
`fire protection to the risk
`Effective furprotection systems make
`tl~e dill'erence between a fire that torpe-
`doesyour business and one that doesn't
`even make the local paper. But don't
`waste valuable resources on overkill
`82 Feature Report: How to
`break emulsions
`Here are some suggestions for handling
`dispersions of immiscible liquids in
`wastewater streams — a vexing problem
`for facilities attempting to comply ~+'~~'
`dischazge limits or recycle water
`89 Focus: A mobile approach
`tv air pollution control
`Portable equipment eases the task of
`handling complex problems in the field
`~ ~ 7 Environmental Manager:
`Fluegas particle size
`Size may not be everything, Uut it is a key
`factor in the selection, design and an~Y'
`sis of air polluvon convol equipment
`~ 37 Plant Notebook: Destroy~g
`organics in wastewater
`A multiplate reactor effectively reduces
`COD, while generating methane for fuel
`
`HYDRITE EXHIBIT 1007
`(2 OF 10)
`
`

`
`Working along
`with your body's
`internal clock,
`you can over-
`come the time-
`synchronization
`woes of trans-
`and interconri-
`nental travel
`
`All kinds of equipment, from
`scrubbers to filters, are going
`~ortable, to control air pollution
`m remote locations
`
`~4~ Planf Notebook: Enhancing
`worker safety
`An enclosed and automated sampler r~
`duces employees' chemical exposure
`~ ~4 Vatavuk Air Pollution
`Control Cost Indexes
`Data through 1997's fourth quarter
`
`INFORMATION
`TECHNOLOGY
`50 A survey says that IT is
`not meeting its potential
`The main barrier to implementation, say
`respondees, is resistance on the part of
`some user employees and executives
`143 Chemputers: Maximize
`profits plantwide
`Realtime, online optimization is gaining
`ground, thanks to software that allows
`for stable control models, and cheaper,
`mor~powerfu] computers
`EQUIPMENT
`& SERVICES
`72 New products
`and services
`~lowmeters ~ Oil filtration system •Ball
`valves • G~ensor transmitter • Flow-
`and-density sensor •Scrubber •Infrared
`8~ transmitter •Centrifugal pumps
`0~ Focus: Wring more from
`dryers and evaporators
`gUyers expect the devices to manage en-
`ergyconsumption, and to customize fin-
`ished products to their customers' specs
`
`.:v
`
`Technology is enabling separation
`of chiral chemicals —stereoisomers
`with identical chemical formulas
`arranged as mirror images
`of each other, but having
`different properties
`
`Optimization packages can
`make improvements in
`plant operating efficiency
`
`116 Show Previews:
`AchemAsia and Miconex
`Highlights from nvo exhibitions to be
`held in Beijing: AchemAsia (May
`11-16), and Miconex '98 (May 2rr29)
`155 Free literature
`g&p Process Equipment •National Instru-
`ments •Triple/S Dynamics • Plexco •
`Megtec Systeiiis •ITT Engineered Valves
`BUSINESS
`48 China: exception to Asia's
`political and economic cis
`Despite the turmoil in that corner of the
`world, the nation expects to spend X750
`billion over the next three ycara to u~r
`grade its infraswcwre and industry
`48 Brazil's chemical industry
`looks to compete globally
`Firms want to: harmonize criteria de6n-
`ing the industry; increase awareness and
`invesunent; and bolster exports
`50 New plants
`Chloralkali •Ethylene •Polypropylene
`• Water-absorbing polymers
`5Z Business briefs
`U.S. Filter •Culligan Water Technolo-
`gies •Coors Ceramics •Pall •Hoechst
`Celanese • GSF Chemicals
`~ 73 Capital spending index
`Covering 18 SIC categories of the CPI
`~ 74 Economic indicators
`Plant Cost ]ndex -latest figure down 0.8
`
`PERSONAL
`ISSUES
`~ ~ Bookshelf
`Reviewed: "McGraw-Hill Encyclopedia of
`Science and Technology," Eighth Ed.
`55 Calendar of events
`EnviroF~cpo • CE Expo • Analytica'98 •
`Miconex '98 • AchemAsia
`67 wha~s Wno
`People on the move, by company
`~ 25 You 8 YourJob:
`Dealing with jet lag
`Traveling across time zones can be gruel-
`ing on your internal time clock
`OPINION
`& COMMENTARY
`5 Lifting the veil
`of uncertainty
`Vendors shouldn't be seen as adversaries
`of user firms; Q~ey often lave the Vest
`perspective on new products and trends
`8 Letters
`Kirkpatrick Awards • Impro~~ng OSHr1 •
`Postscripts
`ADVERTISERS
`• Product Showcase
`• Classified advertising
`• Index of advertisers
`Nor evrroN
`Chemputers VI will be part oFour first-
`ever CE Fxpo, to beheld at the George
`R. Brown Convention Center, in Hous-
`ton,June 3-4. Plan now to attend
`Cover art: SALEM KRIEGEK
`CHEMICAL ENGINEERING /MARCH 1998 3
`
`page 150
`page 157
`page 171
`
`HYDRITE EXHIBIT 1007
`(3 OF 10)
`
`

`
`t~
`ar!
`fil
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`w.
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`ri
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`La
`
`]
`
`f~
`
`emulsifier, or stabiliser, that keeps the
`emulsion stable, binding the internal
`and external phases together, and pre-
`venting droplets from approaching
`each other and coalescing [2].
`Usually emulsifiers are surfactants
`and soaps, present either by them-
`selves or as part of the makeup of a de-
`tergent formulation. An emulsifier con-
`sists of a molecule with hydrophilic and
`hydrophobic ends. In the presence of
`immiscible liquids, the emulsifier mi-
`grates to the interface of the internal
`and external phases, forming a protec-
`tive sheath around droplets of the dis-
`persed phase, as shown in Figure 1.
`While the hydrophobic end of the mole-
`cule migrates, or partitions, intn
`droplets, the hydrophilic end stays in
`the water [l, 2].
`In efi'ect, the emulsifier acts as a cou-
`pling agent, lowering the interfacial
`tension of the internal and external
`phases. When the interfacial tension is
`reduced to zero, an emulsion forms
`spontaneously. This means the surface
`area of the internal phase has reached
`its maximum. The dispersion of fine
`droplets, generally less than 1 pm dia•,
`gives the emulsion a milky appearance.
`This effect can be achieved mechani-
`cally with colloid mills, centrifugal
`pumps and Waring-type blenders [1].
`At equilibrium, the particle size of an
`emulsion's internal phase depends on
`the amount of emulsifier available to
`maintain that equilibrium. Hence, the
`concentration of an emulsifier must be
`balanced by its droplet size to keep p~'-
`ticles from coalescing. The smaller the
`droplets, the more emulsifier required
`to cover the larger surface area. In
`other words, the concentration of emul-
`sifier determines the amount of stabi-
`lizer absorbed at the interface [2l.
`An important factor in emulsion sta-
`bility is the diameter of the dispersed
`droplets, which correlates to the vol-
`ume of the dispersed phase and the in-
`
`to get rid of them. Those who choose not
`to take this methodical approach, may
`be lucky and select the proper removal
`method. Otherwise, they will be
`stumped from the beginning.
`
`Macro globules
`
`>1 Nm
`i.a o.~
`0. t -0.05
`
`X0.05
`
`TABLE 1. HOW PARTICLE SIZE
`COLORS EMULSIONS
`Particle size (pm) Emulsion
`appearance
`Two phases may
`be distinguished
`Milky white
`emulsion
`si~e•wnite
`emulsion
`Gray,
`semihansparent
`Transparent
`microemulslon,
`wBh three or
`morn phases
`EMULSION BASICS
`Whenever two immiscible liquids, such
`as oil and water, contact each other,
`one liquid tends to disperse, but not
`dissolve, in the other. This dispersion of
`liquid, typically in an aqueous medium,
`is an emulsion. Few emulsion droplets
`are smaller than 025 pm in diameter,
`but larger ones can be more than 100
`times greater in size (Table 1).
`The two main categories of emul-
`sions are oil in water (OVA and water
`in oil (WO), with water including the
`most highly polar, hydrophilic (water-
`loving) liquids. Hydrophobic (water-
`hating) nonpolar liquids are considered
`"oils." Of concern for wastewater engi-
`neers is the OW phase, which is divided
`into three subgroups: less than 30%o oil,
`30--74% oil and 74% or more oil [1].
`Emulsions consist of three phases:
`The internal, or discontinuous, phase
`consists of finely divided droplets. The
`eternal, or continuous, phase is the
`matrix that keeps droplets in suspen-
`sion. The interphase consists of an
`
`mulsions in wastewater pose a
`vexing problem for facilities at-
`tempting to recycle water and stay
`in compliance with permissible die-
`chargelimits. But the challenges are no
`less formidable for routine mainte-
`nance. The removal of emulsions, a
`major constituent of which are fats, oils
`and greases (FOGS), is necessary to
`prevent them from depositing on pipes
`and fouling filtration media.
`Not even facilities that use crossflow
`membranes are exempt from the prob-
`lems caused by emulsions. While foul-
`ing may be eluninated, the concentrate
`that accumulates during processing re-
`maina to be dealt with.'I'he concentrate
`coats evaporator heating elements, re-
`quiring frequent cleanup and disposal.
`Cost factors weigh in, with charges for
`hauling water ranging from 15¢ to
`more than $2 per gallon.
`As permissible discharge limits are
`lowered, facilities may find it increas-
`ingly difTicult to stay in compliance. In-
`deed, afacility that is permitted to dis-
`charge b0 ppm of organic waste may
`believe it is in a safe range if the con-
`tent ofits water is only 30 ppm of oil. To
`the contrary, that oil may be putting a
`severe strain on the facilit}~s discharge
`permit for total chemical oxygen de-
`mand (COD), which includes any com-
`poundthat can be oxidized, but may be
`more difTicult to remove. And for facili-
`ties attempting to recycle water in a
`closed-loop process, FOGS simply can-
`not be ignored.
`Some of the havoc caused by emul-
`sions can be avoided if emulsions are
`broken and removed from wastewater
`streams. Successful emulsion breaking
`requires n basic understanding of
`emulsions, their chemical composition,
`and the technologies required to re-
`move them from water. Chemical engi-
`neers must ask what types of emul-
`sions are involved and then decide how
`GeorgeAlther, Biomin, Inc.
`
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`~s,~ece~ary toe~cycl~~~vvater c~~d met disch~~.rge lir~,~s
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`
`HYDRITE EXHIBIT 1007
`(4 OF 10)
`
`

`
`THE RIGHT BALANCE
`/~ key consideration in the formulaFion
`/`'1 of emulsions and, therefore, a factor
`in determining how they can be broken —
`is the hydrophile vs. lipophile balance
`(HLB) of emulsifiers. This measure of the rel-
`ative simultaneous attraction of an emulsi-
`~ier for oil and water is determined by the
`chemiml mmposifion and the extent of ion-
`• ization of fhe surfactant. For example, the
`HLB of propylene glycol mono stearate is
`strongly hydrophilic, while sodium stearate
`is strop ly hydrophobic. Here are recom-
`mend HlB numbers of emulsifiers oc-
`cording fo applicafion:
`HLBNUMBER
`APPl1GAT10N
`Emulsifier for waterin-oil
`4-6
`(WO) systems
`7-9
`Wetting agents
`8-18
`Emulsiers for oil-in-water
`(OMB systems
`13-15
`Detergents
`15-18
`Solubilizen
`For an oil contaminant ro be solu6ized in .
`water, the presence of a surfactant with a
`high HLB number is required. The following
`shows the acfivity of emulsified oil based on
`.the HL8 number of the surfactant presenh
`HLB RANGE
`ACTION IN WATER
`1-,4
`Not dispersible
`3-b
`Poor dispersibiliiy
`6-8
`Milky dispersion
`,. oFte~vigorousagitation
`10-13
`Stable milky dispersion
`13+
`Clear hansparenry
`(micrcemulsion)
`,. Water temperature can influence the effi-
`ciencyof anemulsifier. Nonionic surfactants
`in aqueous solutions tend to be more soluble
`when the water is cold. As the temperature
`increases, turbidly increases fo a maximum
``cbud point. By determining the cloud point,,:
`the HlB value can be estimated.
`Astable emulsion shows no indication of
`coalescence or creaming during its normal-
`e~cpectcd shelf life, even if it is frozen and
`thawed repeatedly, or exposed to elevated
`temperatures (40-50°C).
`To counter the effects of emulsifiers that
`'enhance dispersion, suspension and wet- ,
`ting of particles, emulsifiers of the oppo-
`site type , ~~~~~~~<an disrupt the HIB, can
`be applied. Depending on the emulsion, a
`strongly hydrophilic surfactant, such as
`pclysork~ate 80, or a strongly lipophilic sur
`Factant, such as monoglyceryl or diglyceryl
`O
`oleate, can break the emulsion (8].
`
`settling velocity varies as the square of
`the particle diameter. Since oil's den-
`sity is usually less than that of water,
`upward sedimentation, or creaming,
`will occur [1].
`Flocculation, or aggregation, is a sec-
`ond process that takes place in emul-
`sions with low-internal-phase ratios, as
`typically found in wastewater. Parti-
`cles slide together without coalescing to
`form clumps, or chains of clumps, of
`larger effective size. The settling rate
`then increases, even though the parti-
`cles do not behave like spheres, as
`Stoke's Law demands [2],
`Emulsifier solubility can be en-
`hanced, if necessary, by adding a co-sol-
`vent or co-emulsifier, such as propylene
`glycol, that will act as a coupler to as-
`sure stability at all temperatures. A
`blend of several surfactants can be
`added to form a tightly packed film
`around the oil droplets. The presence of
`finely divided solids, such as clays, can
`also act as emulsifiers. The oil droplets
`then coat these solids, resulting in an
`emulsion or settling.
`Electrical charge
`Across the interface of all solids and liq-
`uids is an electrokinetic gradient,
`called the Zeta potential, that is largely
`responsible for colloidal stability. Dis-
`charge of the Zeta potential, accompa-
`nied by precipitation of colloid, occurs
`by addition of polyvalent ions of a sign
`opposite that of colloidal particles.
`Adding an ionized emulsifier that is
`attracted to the oil-water interface will
`impart a positive or negative charge to
`each droplet. The coalescence rate will
`slow down as electrically repulsive
`forces build up between droplets.
`Oil droplets in an oil-in-water emul-
`sion are likely to have a negative
`charge, as described by the Helmholtz
`theory of the electrical double layer,
`wtuch states that if the negative
`charges are aligned or closely bound to
`
`terfacial area available. For example, if
`an oil is added to a container partially
`filled with water, the oil, upon impact,
`will coalesce acid float as sheen on the
`a~ater's surface. The oil forms a second
`layer or phase because its specific grav-
`ity is lower than that of water.
`If water is then blasted into the con-
`tainer, the physical impact of the water
`on the oil will cause some droplets to
`emulsify, or disperse, in the water.
`When the blast ceases, oil droplets will
`coalesce quickly.
`A surfactant or emulsifier added to
`the container will disperse the oil into
`the water. The system can be imagined
`as a collection of small spheres dis-
`persed in the continuous water please.
`Unless the droplets are small enough to
`be kept in suspension by thermal
`forces, they will eventually settle out or
`rise to the surface and form a layer of
`droplets in a process called creaming.
`Left idle, oil droplets will collide and co-
`alesce, unless enough emulsifier is
`added to cover the entire interfacial
`area. Over a period of time, larger par-
`ticles will rise to the surface and coa-
`lesceinto asingle layer f 1].
`The creaming of an emulsion, or how
`fast an oil droplet will rise to the
`water's surface, is governed by Stoke's
`Law, which states:
`where:
`u =the rate of sedimentation of a
`spherical particle
`G = acceleration of gravity
`~ =radius of the particle
`dl = density of liquid in the internal
`Phase
`~2 = density of liquid in the external
`Phase
`~ = viscosity of the emulsion
`Large droplets rise, or fall, faster
`than small ones, and drops move faster
`in a low_viscosity liquid. Therefore, if dl
`is less than d2, the particle will rise, but
`~ d2 is larger than dl, it will fall. The
`
`HYDRITE EXHIBIT 1007
`(5 OF 10)
`
`

`
`;OIL IN.WATERa~ ~~WA7ERkI~N OIL
`
`o— Oil ~ ~~,~~~~-~ Water 0.
`~~~~rPP~~
`~~f ~~~~
`'°Pf T'~~~
``~l~
`
`FEATURE REPORT
`
`FIGURE 1. (top)
`Added to an emulsion, a surtactant
`has a tendency toward orientation.
`The hydrophilic end Is attracted
`to the water, while Its hydrophobic
`end Is oriented toward the oil
`
`FIGURE 2 (bolow)
`The interphase o} an emulsion,
`conslating of an emulsifier orstabilizer,
`prevents dispersed oil droplets
`fn waterfrom coalescing
`
`the interlayer, charges of the opposite
`type will line up parallel to them, form-
`ing an electrical double layer that
`causes oil droplets to repel each other.
`Surfactants are essential compo-
`nents of formulations for processing
`textiles, pulp and paper, and deter-
`gents. They aid in dispersion, suspen-
`sion, foam suppression and particle
`wetting. But surfactants can also make
`FOG in wastewater extremely dif~`icult
`to clean up due to the solubility of oil
`emulsified by I,hem.
`The molecular structure of surfac-
`tants consist of two distinct sections.
`One is polar and water soluble. Acetic
`acid, for example, the smallest car-
`boxylic acid having any hydrocarbon
`character, is very soluble in water.lfie
`nonpolar portion of a surfactant is in-
`soluble in water [3].
`When a surfactant, or emulsifier, is
`added to an oil-in-water emulsion, it
`has a tendency toward orientation,
`whereby the emuls~er's hydrophilic
`end is dissolved into the water and its
`nonpolar hydrocarbon end is oriented
`toward the oil. When the molecules be-
`come crowded around an oil droplet,
`and space becomes limited, the film of
`surfactant around the droplet com-
`presses and the surfactant molecules
`are packed in an oriented position, as
`shown in Figure 1.
`If enough emulsifier is added to coat
`the entire surface area of the droplets,
`a stable emulsion will form that can
`last for years —such as those found in
`cosmetics and shampoos. The emulsi-
`fier thus forms a skin around each
`droplet, preventing it from colliding
`with other droplets. When oil is emulsi-
`fied in wastewater, usually at a few
`ppm to 5%, it takes only a small
`amount of detergent to emulsify the oil
`into a stable emulsion [2].
`84 CHEMICAL ENGINEERING /MARCH 1998
`
`EMULSION BREAKING
`Emulsion breaking, or demulsification
`is the separation of a dispersed liquid
`from the liquid in which it is sus-
`pended. All chemical and mechanical
`methods of emulsion breaking con-
`form to Stoke's Law.
`The objective of demulsification is to
`destroy the interface and drive the
`surfactant to either the oil side or the
`water side, allowing the oil particles
`and sediments to coalesce and rise to
`the surface, as in creaming. Demulsifi-
`cation can be enhanced by decreasing
`water-phase viscosity or increasing oil
`viscosity. Increasing the diameter of
`oil droplets and lowering the density
`of oil to water also works.
`Demulsification is divided into sev-
`eral processes:
`• Gravity separation of free, nonemul-
`sified oil
`• Chemical treatment and separation
`of emulsified oil
`• Electrolytic methods, which are not
`covered in this article
`To design a demulsification program,
`the engineer must first answer a num-
`ber of questions:
`• What type of emulsion is involved?
`• What kind of oil is in the emulsion?
`• What is the percent oil in water?
`•What is the wastewater's pH?
`• What is the oil-particle-size distrib-
`ution? For example, are the droplets
`large enough to be visible?
`• Are there solids present? If so, are
`they oil-wetted orwater-wetted?
`•Are surfactants present in either
`phase? If so, are they cationic, an-
`ionic or nonionic? Are they oil-solu-
`ble or water-soluble?
`• What type of mechanical treatment
`has the wastewater experienced
`prior to collection?
`
`• Is there violent mixing or sharp
`bends in the effluent pipes [4,5,6]?
`As a class, oils are nonionized and non-
`conductive. Inorganics are not soluble
`in most oils. The objective then is to
`move the emulsion breaker out of the
`oil droplets into the water phase.
`In wastewater, oils are defined as
`substances that can be extracted from
`water by hexane, carbon, tetrachloride,
`chloroform, fluorocarbon and Freon
`113 [6] .'I`hese tests are found in ASTM
`D 2910 and other literature [7].
`In addition to oil, used process water
`may contain metal shavings, silt, sur-
`factants, cleaners, soaps, solvents,
`metal particles and other residue that
`will accumulate in the rag layer unless
`it settles out by gravity. Depending on
`the process, the FOGS found in these
`emulsions may be fats, lubricants, cut-
`tingfluids, heary hydrocarbons such as
`tar, grease, crude oils and diesel oils,
`and light hydrocarbons, including gaso-
`line, kerosene and jet fuel. Their con-
`centrations can range from a few ppm
`to X10% of the wastewater [6].
`The stability of emulsified droplets is
`maintained by anionic and nonionic
`surfactants, and solids present on the
`interfacial film. An emulsion achieved
`with solids is most stable when the con-
`tact angle of the solids with the inter-
`face is close to 90 deg. While the Zeta
`potential of the solids may increase the
`strength and stability of the emulsion,
`surfactants are largely responsible for
`the film's high Zeta potential, high in•
`terfacial-shear viscosity, high interfa-
`cial elasticity, and relatively low inter-
`facial tension [2].
`Counteracting emulsions
`There are several strategics for coon•
`teracting emulsions:
`• Decompose the emulsion, using dig-
`solved air flotation, ozonation or
`other oxidation process. This method,
`however, is expensive
`• Chemically react the emulsion, mod-
`ifying the surfactant's charge so that
`it no longer acts as an emulsifier. For
`an ionic surfactant, neutralizAtion is
`often the simplest method, using an
`acid, base or ionizer. If a calcium or
`magnesium salt, such as CaCI or
`MgSO4 is added to an emulsion sta-
`bilized by asodium soflp,the soap will
`convert into a calcium or magnesium
`
`'
`
`HYDRITE EXHIBIT 1007
`(6 OF 10)
`
`

`
`Pump
`
`i_
`
`Rinse water
`,~
`~ - . _`
`
`FIGURE 3. A standard wastewater-treatment
`facility will remove oily contaminants to about
`30 ppm. Passing the water through a column
`of organically modified clay and activated carbon
`removes the remaining oil and surfactant, yielding
`water that is suitable for recycling and reuse
`
`,'i;~r~r
`A3r~~~
`r'~i~~'~u?2
`~~~ t
`
`------------ ---
`_
`
`-------- - - ---
`
`pH controllers
``~t
`
`'S1=
`~;~
`tii~ti~t;~,'
`
`~,
`, ~7'- k1tr~..
`
`~
`+
`
`~
`
`T
`~,~,.
`k
`~i"
`
`i
`
`K9~~'~~:
`_ ..
`~~ ~d
`;` Organoclay
`traceoil
`_removal__
`-
`
`~:3
`
`~~'
`;♦
`~ ~~~
`r; T
`
`Activated-
`VOCs
`removal
`
`~
`
`~
`
`~
`
`~
`
`Source: Crcat Lakes Environmental, Ina.
`
`about 162° F) results in separation, and
`this approach is. economically feasible,
`slflm the oil off the surface. Run the
`water through an absorber vessel filled
`with organoclay to remove the remain-
`ingtraces ofoil, and follow with a treat-
`ment of activated carbon. The water is
`then available for reuse.
`Another procedure, the Babcock Test
`(ASTM D1497), can also be used to de-
`termine the amount of oil in the water
`and its state of emulsification. In this
`procedure, a sample of the emulsion is
`placed into a long, thin, graduated
`flask. Sulfuric acid is added to destroy
`the effect of the emulsifier, then the
`bottle is spun in a centrifuge until the
`oil separates. The amount of oil present
`can be read ofTthe bottle.
`Oil-particle-size distribution is also
`of use, and can be done by sight. If the
`drop size is above 200 }im, it is visible.
`Particle sizes of 100-10 }un cause a
`milky white appearance, 10-1 aun, a
`bluish-white color, and 1-0.5 }un, a
`smoky gray color. Below 0.5 pm, the liq-
`uid is transparent. Light scattering de-
`vices and refractive index measure-
`ments are the primary instruments
`used to measure droplet size [S].
`Particle charge measurements hove
`been reported to aid in determining the
`treatment method. Ionic emulsifiers
`contribute a charge to the interface
`that can be determined by electrodes. If
`the external phase is nonconductive,
`such as in a water-in-oil emulsion,
`which can consist of 80°,~ water, the
`drops acquire a static charge. Charges
`can be induced on the particles by an
`electric or magnetic field (1].
`(Continues on next page)
`CHEMICAL ENGINEERING / MARCN 1998 85
`
`ice,
`
`Ferric
`..
`
`separator
`
`JAEGER
`
`. ((~
`
`~
`
`a,:-
`
`~")
`~
`~. C.8U8t~C ~. ~ ~
`
`' ,
`
`C hCIT1IC8I
`treatment
`
`Of IS ',';.
`~: ~
`
`soap, which is less sol-
`uble inwater because the
`interfacial film has changed. The
`emulsion may break
`• Increase the solubility of the surfac-
`tant in either bulk phase. Alcohol or
`other polar solvents, such as acetone,
`can be used to increase solubility in
`the water phase and pull the emulsi-
`fier out of the oil phase. If the aque-
`ous phase is a brine, dilution with
`water may be all that is needed to
`achieve separation
`• Disrupt the oriented structure of the
`emulsifier's interfacial phase with
`demulsifiers. Because these materi-
`als are not very soluble in either
`phase, they concentrate at the inter-
`face. Separation occurs when the
`agents insert themselves between
`the surfactant molecules, increasing
`the intermolecular distance and
`weakening the binding forces con-
`atructed by the emulsifier [5].
`Chemical demulsifiers provide the op-
`posite charge to the emulsion, allowing
`the accumulated electrical charge on
`the interface of the emuls~ed oil
`droplets to be neutralized. Normally,
`cationic dem~sifiers, which exhibit a
`Positive charge when dissociated in
`Warr, are used to destabilize oil-water
`emulsions. Coalescence occurs when
`the ?,eta potential of the surfactant ap-
`Proaches zero, at which point coales-
`cence is inprogress [6].
`Though organic emulsion breakers
`produce less sludge than inorganic
`coagulants, ferric and aluminum
`chloride, continue to be among the
`most wic]ely used chemicals for emul-
`
`sion breaking (Table 2).
`Ferric chloride and aluminum chlo-
`ride break emulsions by lowering the
`wastewater's pH, which aids in the coa-
`lescence of oil droplets. The disadvan-
`tage of using these inorganic com-
`pounds, however, is that they build up
`sludge and are difficult to remove.
`Salts such as aluminum sulfate add
`ionic strength and a high charge, which
`help later removal of surfactants by ac-
`tivated carbon, although pH must be
`raised back to 8 to do that successfully.
`However, removal of as much of the
`solids as possible prior to emulsion
`breaking will reduce the demand for
`treatment chemicals and lower pro-
`cessing costs [4].
`Testing procedures
`Before applying treatment to break an
`emulsion, the first step is to establish
`that an emulsion, with two separate
`phases, is present. If the wastewater is
`cloudy or opaque, with visible amounts
`of a second liquid at the top or bottom of
`the sample container, or sticking to its
`side, it is probably an emulsion. But it
`could also be a slurry of finely divided,
`colloidal solids [5].
`To test, mix the sample thoroughly,
`place it into a test tube, place the test
`tube into a hot bath. Does separation
`occur? Do solids settle? Is there a
`change of color?
`Many emulsions are light brown or
`cream colored. As they begin to break,
`they first darken, then separate. U the
`liquid is n clear, one-phase liquid, but
`becomes cloudy upon being heating, a
`microemulsion or nonionic detergent
`may be present. If simple heating (to
`
`HYDRITE EXHIBIT 1007
`(7 OF 10)
`
`

`
`FEATURE REPORT
`
`Physical separation methods
`Most oily waste is a combination of
`free, nonemulsified oil, stable emulsi-
`fied oil and insoluble solids, including
`grit, metal fines, carbon, paint, pig-
`ments and corrosion products. There
`are several methods for physical sepa
`ration of emulsions. Some are more of
`fective than others. There is a myriad
`of equipment and configurations avail-
`able for emulsion separation, including
`coalescers, centrifuges and skimmers:
`Coalesces. Suitable for emulsions
`that have been induced mechanically,
`process separators can remove free oil
`droplets by gravity if they are larger
`than 0.015 cm dia. Proper sizing and pip-
`ingdesign of the separator, which c