CO2 Solutions Inc.
`Exhibit 2008
`Akermin, Inc. v. CO2 Solutions Inc.
`IPR2015-00880
`Page 1 of 12
`
`

`
`EXECUTIVE EDITOR
`Jacqueline I. Kroschwitz
`
`EDITOR
`
`Mary Howe-Grant
`
`Page 2 of 12 L
`
`Page 2 of 12
`
`

`
`ENCYCLOPEDIA OF
` CHEMICAL
`
`TECHNOLOGY
`
`FOURTH EDITION
`
`VOLUME 20
`
`POWER GENERATION
`E
`I
`-TO
`
`RECYCLING, GLASS
`
`) New York
`
`- Chichesterl
`
`%
`
`% A wIIey-Interscience Publication
`’ JOHN W|LEY_& SONS
`- Toronto
`Singapore
`
`A
`-V Brisbane
`
`Pagé 3 of 12 %
`
`Page 3 of 12
`
`

`
`This text is printed on acid-free paper.i
`
`J Copyright © 1996 by John Wiley & Sons, Inc.
`
`All rights reserved.’ Published simultaneously in Canada.
`
`Reproduction or translation of any part of this work
`beyond that permitted by Sections 107 or 108 of the .
`1976 United States Copyright Act without the permission
`of the copyright owner is unlawful. Requests for
`‘permission or further information should be addressed to
`the Permissions Department, John Wiley & Sons, Inc.,
`605 Third Avenue, New York, NY 10158-0012.
`
`Library ofiCongrless Cataloging-in-Publication Data
`
`Encyclopedia of chemical technology/executive editor, Jacqueline
`I. Kroschwitz; editor, Mary I~Iowe—Grant.-—4th'ed.
`p. cm.
`
`At head of title: Kirk-Othmer.
`“A Wiley-Interscience publication.”
`Contents: v. 20, Power Generation to Recycling, Glass
`ISBN 0471-52689-4 (v. 20)
`
`I. Kirk, Raymond E.
`1. Chemistry, Technical——Encyclopedias.
`(Raymond Eller), 1890-1957.
`II. Othmer, Donald F. (Donald
`Frederick), 1904-1995.
`III.‘ Kroschwitz, Jacqueline I., 1942- .
`IV. Howe-Grant, Mary, 1943- . V. Title: Kirk-Othmer encyclopedia
`of chemical technology.
`»
`A
`"
`TP9.E685 1992
`'
`660’.03——-dc20
`
`91-16789
`
`.
`
`Printed in the United States of America
`
`10987654321
`
`Page 4 of 12
`
`Page 4 of 12
`
`

`
`Vol. 20
`
`REACTOR TEC4lflNOl'_OGY‘~
`
`1007
`
`REACTOR TEC‘HNQLQGY
`
`.
`
`.
`
`Reactor technology comprises the underlying principles of chemical reaction,
`engineering (CRE) and the practices used in their _application. The focuses of
`reactortechnology arereactor configurations, operating conditions, external op-
`erating environments, developmental history, industrial application, and evolu-
`tionary change. Reactor designs evolve from the pursuit of new products and
`uses, higher conversion, more favorable reaction selectivity, reduced fixed and
`operating costs, intrinsically safeoperation, and environmentally acceptable pro-
`, cessing.
`Early in the development of chemical reaction engineering, reactants and
`. products were treated as existing in single homogeneous phases or several dis-
`» crete phases. The technology has evolved into viewing reactants and products as
`residing in interdependent environments, a most important factor for multiphase
`‘reactors which are the most common types encountered.
`'
`-
`.
`Many, but not all, reactor configurations are discussed. Process design,
`catalyst manufacture, thermodynamics, design of experiments (qv), and process
`economics, as Well as separations, the technologies of which often are appli-
`« cable to reactor technology, are discussed elsewhere in the Encyclopedia (see
`CATALYSIS; SEPARATION; THERMODYNAMICS).
`.
`Besides stoichiometry and kinetics, reactor technology includes require-
`‘ ments for introducing and removing reactants and products, efficiently supplying
`and Withdrawing heat, accommodating phase changes and material transfers, as-
`i suring efficient contacting of reactants, and providing- for catalyst replenishment
`or regeneration. ‘Consideration must be given to physical properties of feed and
`products (vapor, liquid, solid, or combinations), characteristics of "chemical reac-
`tions (reactant concentrations, paths and rates, operating conditions, and heat
`, addition or removal), the nature of anycatalyst used (activity, life, and phys-
`ical form), and requirements for contacting reactants and removing products
`_(floW characteristics, transport phenomena, mixing requirements, and separat-
`ing mechanisms).
`’
`T
`.
`All the factors are interdependent and must be considered together. Re-
`quirements for contacting reactants and removing products are a central focus
`in applying reactor technology; other factors usually are set by the original se-
`lection of the reacting system, intended levels of reactant conversion and product
`selectivity, and economic and environmental considerations. These issuesshould
`be taken into account When determining reaction kinetics from laboratory and
`bench-scale data, designing and operating pilot ‘units, scaling up to large units,
`. and ultimately in designing, operating, and improving industrial plant perfor-
`mance.
`
`a
`
`Reactor Types and Characteristics
`
`Specific reactor characteristics dependon the particular use of the reactor as a
`laboratory, pilot plant, or industrial unit. All reactors have in common selected
`characteristics of four basic reactor types: the Well‘-stirred batch reactor, the
`semibatch reactor, the continuous-flow stirred-tank reactor, and the tubular
`reactor (Fig. 1). A reactor may be represented by or modeled after one or a
`
`'
`
`Page 5 of 12
`
`Page 5 of 12
`
`

`
`1oo3.
`
`REACTOR TECHNOLOGY
`
`Vol. 20
`
`Other reactants
`
`added continously
`
`Reactants at
`start
`J1
`
`.
`He_ating/
`' cooling
`
`~
`
`E
`E
`
`0 Time
`
`Reactants at
`start
`
`Heatingl
`cooling
`
`7
`
`,
`
`E
`E
`§
`o
`
`Time
`
`(b)
`
`3
`2
`1
`Stage number
`
`-
`
`5
`(Y!
`
`E
`
`8 E
`
`C.)
`A
`
`(a)
`
`1
`
`|
`
`I
`
`-
`Feed
`
`'_J_‘
`
`I
`
`I
`
`_
`Products'
`
`_
`_’
`Heating/cooling
`
`‘
`
`(c)
`
`C
`.2
`
`*5
`EO
`
`CO0 D
`
`
`
`Feed l
`
`istance along reactor
`
`Heating/cooling
`
`an
`
`Fig. 1. Reactor types: (a) batch, (b) semibatch, (c) continuous-flow stirred-tank, and
`(d) tubular.
`O
`‘
`'
`‘
`
`,
`
`combinationof these. Suitability’ of a ‘model depends on the extent to Which the
`impacts of the reactions, and thermal and transport processes, are predicted for
`conditions outside of_the database used in developing the model (1-4)-.
`Batch Reactor. A batch reactor is one in Which a feed material is treated
`as a Whole for a fixed period of time. Batch reactors may be preferred for
`small-scale production of high priced products, particularly if many sequential
`operations are employed to obtain high product yields, eg, a process requiring
`a complex cycle of temperature—pressure—reactant additions. Batch reactors '
`also ‘may be justified When multiple,
`low Volume products are produced in '
`the same equipment or When continuous flow is difficult, as it is. with highly
`Viscous or sticky solids—laden liquids, eg, in the manufacture of polymer resins
`Where molecular Weight and product quality are markedly affected by increasing
`
`Page 6 of l2
`
`Page 6 of 12
`
`

`
`Vol. 20
`
`REACTOR TECHNOLOGY
`
`1009
`
`’
`
`viscosity and heat removal demands. Because residence times can be more
`uniformin batch reactors, better yields and higher selectivity may be obtained
`than with continuous reactors. This advantage exists when undesired reaction
`products inhibit the reaction, side reactions are of lower order than that desired,
`or the product is an unstable or reactive intermediate-
`Batch reactors often are used to develop continuous processes because of I
`their suitability and convenient use in laboratory experimentation. Industrial
`practice generally favors processing continuously rather than in_single batches,
`because overall investment and operating costs usually are less. Data obtained
`in batch reactors, except for very rapid reactions, can be well defined and used
`to predict performance of larger scale, continuous-flow reactors. Almost all batch
`reactors are well stirred; thus, ideally, compositions are uniform throughout and
`residence times of all contained reactants are constant.
`.
`I
`.
`Semibatch Reactor. The semibatch reactor is similar to the batch reactor
`but has the additional feature of continuous addition or removal of one or more
`‘ components. For example, gradual addition of chlorine to a stirred vessel con-
`taining benzene and catalyst results inhigher yields of di- and trichlorobenzene
`than the inclusion of chlorine in the original batch. Similarly, thermal decompo-
`sition of organic liquids is enhanced by continuously removing gaseous products.
`Constant pressure can be maintained and chain—terminating reaction products '
`removed from the system. In addition to better yields and selectivity, gradual
`addition or removal assists in controlling temperature particularly when the net
`' reaction is highly exothermic. Thus, use of a semibatch reactor intrinsically per-
`mits more stable and safer operation than in a batch operation.
`_ Continuous-Flow Stirred—Tank Reactor.
`In_ a continuous-flow stirred-tank
`reactor (CSTR), reactants and products are continuously added and Withdrawn.
`In practice, mechanical or hydraulic agitation is required to achieve uniform
`composition and temperature, a choice strongly influenced by process considera-
`tions, ie, multiple specialty product requirements and mechanical seal pressure
`limitations. The CSTR is the idealized opposite of the well-stirred batch and
`- tubular ‘plug-flow reactors. Analysis of selected combinations of these reactor
`types can be useful in quantitatively evaluating more complex gas-, liquid-, and
`solid-flow behaviors.
`’
`’
`.
`Because the compositions of mixtures leaving a CSTR are those within
`the reactor, the reaction driving forces, usually reactant concentrations, are
`necessarily low. Therefore, except for zero- and negative-order reactions, a CSTR
`_ requires the largest Volume of the reactor types to obtain desired conversions.
`However, the low driving force makes possible better control of rapid exothermic
`and endothermic reactions. When "high conversions of reactants are needed,
`several CSTRS in series can be used. Equally good results can be obtained
`by dividing a single vessel into compartments While minimizing back—'mixing
`and short-circuiting. The larger the number of stages, the closer performance
`approaches that of a tubular plug—flow reactor.
`'
`Continuous—flow stirred—tank reactors in series are simpler and easier to
`designfor isothermal operation than are tubular reactors. Reactions with nar-
`row operating temperature" ranges or those requiring close control of reactant
`concentrations for optimum selectivity benefit from series arrangements. If se-
`vere heat-transfer requirements are imposed, heating or cooling zones can be
`
`I
`
`Page 7 of 12
`
`Page 7 of 12
`
`

`
`1010
`
`REACTOR TECHNOLOGY
`
`Vol. 20 '
`
`incorporated within or external to the CSTR. For example, impellers or cen-
`trally mounted draft tubes circulate liquid upward, then downward through ver-
`tical heat-exchanger tubes. In a similar fashion, reactor contents can be recycled
`through external heat exchangers.
`Tubular Reactor. The tubular reactor is a vessel through which flow is
`continuous, usually at steady state, and configured so that conversion and other
`dependent Variables are functions of position Within the reactor rather than of
`time. In the ideal tubular reactor, the fluids flow as if they Were solid plugs
`or pistons, and reaction time is the same for all flowing material at any given
`tube cross section; hence, position_is analogous to time in the well-stirred batch
`reactor. Tubular reactors resemble batch reactors in providing initially high
`driving forces, which diminish as the reactions progress down the tubes.
`Flow in tubular reactors can be laminar, as with viscous fluids in small-
`diameter tubes, and greatly deviate from ideal plug-flow behavior, or turbulent,
`as with gases, and consequently. closer to the ideal (Fig. 2). Turbulent flow
`generally is preferred to laminar flow, because mixing and heat transfer when
`normal to flow are improved and less back-mixing is introduced in the direction
`of flow. For slow reactions and especially in small laboratory and pilot-plant
`reactors, establishing turbulent flow can result in inconveniently long reactors
`or may require unacceptablyhigh feed rates. Depending on the consequences
`in process development and impact on process economics, compromises, though
`necessary, may not prove acceptable.
`Multiphase Reactors. The overwhelming majority of industrial reactors
`are multiphase reactors. Some important reactor configurations are illustrated
`in Figures 3 and 4. The names presented are often employed, but are not the
`only ones used. Thevpresence of more than one phase, whether or not it is
`flowing, confounds analyses of reactors and increases the multiplicity of reactor
`configurations. Gases, liquids, and solids each flow in characteristic fashions,
`either dispersed in other phases or separately. Flow patterns in these reactors
`are complex and phases rarely exhibit idealized plug-flow or well-stirred flow
`behavior.
`
`A fixed—bed reactor is packed with catalyst. If a single phase is flowing, the
`reactor can be analyzed as a tubular plug-flow reactor or modified to account for
`axial diffusion. If both liquid and gas or vapor are injected downward through
`
`.
`
`Flow
`regime
`
`Plug flow
`
`Laminar
`
`Velocity
`profile
`
`l
`
`Constant
`
`velocity
`
`E Parabolic
`
`Turbulent
`
`J Flattened
`
`Fig. 2. Flow characteristics for single-phase flows.
`
`Page 8 of 12
`
`Page 8 of 12
`
`

`
`Vol. 20
`
`.
`
`A
`
`Feed
`‘
`men balls
`Catalyst
`,
`
`1
`
`.
`
`l
`
`Product
`la)
`
`REACTOR TECHNOLOGY
`
`1011
`
`Feed
`
`—
`
`I
`
`"r
`
`
`
`-->Product
`
`V
`‘ Catalyst in —+
` _|nterbed
`Flue
`7%‘
`:> gas heating Feed—E
`—>Product
`/E__
`J
`‘L
`L» Catalyst out
`
`(b)
`
`Product
`(c)
`
`(d)
`
` ‘ Product
`
`Fresh and
`
`recycled gas
`
`Fig. 3. Multiple fixed-bed configurations: (a) adiabatic fixed-bed reactor, (b) tubular
`fixed beds, (c) staged adiabatic reactor with interbed heating (cooling), ((1) moving radial
`fixed-bed reactor, and (e) trickle beds in series.
`1
`
`the catalyst bed, or if substantial amounts of Vapor are generated internally, the
`reactors are mixed-phase, downflow, and fiXed‘—bed reactors. If the liquid and
`gas rates are so low that the liquid flows as a continuous film over the catalyst,
`the reactors are called trickle beds. Trickle beds have potential advantages of
`lower pressure drops and superior access for gaseous reactants to the catalyst;
`however, restricted access can also be a disadvantage, -eg, where direct gas .
`contact promotes undesired side reactions.
`4 At higher total flow rates, particularly when the liquid is prone to foaming,
`the reactor is a pulsed column. This designation arises from the observation
`that the pressure drop Within the catalystlbed cycles at a constant frequency as
`a resultof liquid temporarily blocking gas or Vapor pathways. The pulsed column
`is not to be confused with the pulse reactor used to obtain kinetic data in which a
`pulse of reactant is introduced into a tube containing a small amount of catalyst.
`Downflow of reactants is preferred because reactors are more readily de-
`signed mechanically to hold a catalyst in place and are not prone to inadvertent
`excessive velocities, which upset the beds. Upflow is used less often but has the
`advantage of optimum contacting between gas, liquid, and catalyst over a Wider
`range of conditions. Mixed-phase, upflow, and fiXed—bed reactors offer higher
`liquid holdups and greater assurance of attaining uniform catalyst wetting and
`radial flowdistribution, the consequences of which are more uniform tempera‘-
`ture distribution and greater heat transfer.
`At high liquid flow rates in these co-current fiXed~bed reactors, gas becomes
`the dispersed phase and bubble flow develops; flow characteristics are similar
`
`Page 9 of 12
`
`Page 9 of 12
`
`

`
`1012
`
`REACTOR TECHNOLOGY
`
`Dispersed
`nqugd
`¢
`
`—> Product
`
`
`
`5 |
`
`—U—i_> Product
`
`
`
`Continuous
`Phase
`
`(a)
`
`(b)
`
`(c)
`
`_
`De—entrained
`Vapor
`
`iron. 20
`
`Product
`
`Feed
`
`\,
`
`Continuous
`phase
`
`Digpgrsed
`phase
`
`-
`
`Transfer-
`line reactor 5'4‘.
`
`
`
`Liquid
`Liquid-
`gas bubbles’
`
`Liquid
`recycle
`'
`_
`'—%lCiLf(|jd_—8§S
`
`F—> Product
`
`Gasl
`
`Steam stripping
`
`
`
`
`Flue gas
`
`FlUld‘bed
`regenerator
`
`Feed
`
`<_ A”
`Transfer line
`
`‘_?:l-Ugadas
`
`(cl)
`
`(e)
`
`.
`
`Feed
`
`Solid feed
`
`l
`
`)4
`Product
`
`G85
`
`Product
`.
`
`(f)
`
`'
`
`(g)
`
`Fig. 4. Multiphase fluid and fluid—solids reactors: (a) bubble column, (b) spray column,
`(c) slurry reactor and auxiliaries, (d) fluidization unit, (e) gas—liquid—solid fluidized
`reactor, (f) rotary kiln, and (g) traveling grate or belt drier.
`
`to those in countercurrent packed-column absorbers. At high gas rates, spray
`and slug flows can develop. Moving beds are fixed-bed reactors in which spent
`catalyst or reactive solids are slowly removed from the bottom and fresh material
`is added at the top. A fixed bed that collects solid impurities present in the ‘feed »
`or produced in the early reaction stages is a guard bed. If catalyst deposits are
`periodically burned or otherwise removed, the operation is cyclic, and the catalyst
`remaining behind the combustion front is regenerated.
`
`Page 10 of 12 p
`
`Page 10 of 12
`
`

`
`T Vol. 20
`
`REACTOR TECHNOLOGY
`
`1013
`
`In bubble column reactors, ‘gas bubbles flow upward through a slower
`moving liquid. The bubbles, which rise in essentially plug flow, draw liquid
`in their wakes and thereby induce back-mixing in the liquid with which they
`have come in contact. Analogously, in spray columns, liquid as droplets descend
`through a fluid, usually a gas. Both bubble and spray columns are used for
`reactions Where high interfacial areas between phases are desirable. Bubble
`column reactors are used for reactions where the rate—limiting step is in the
`liquid ‘phase, or for slow reactions where contacting is not critical. An important
`variant of the bubble column reactor is the loop reactor, commonly used for
`both multiphase and highly viscous systems. Loop reactors are distinguishable
`by their ‘hydraulically or mechanically driven fluid recirculation, which offers
`the benefits of the Well-stirred behavior of CSTRs and high average reactant
`concentrations of tubular reactors.
`
`Reactors are termed‘ fluidized or fluid beds if upward gas or liquid flows,
`alone or in concert, are sufficiently high to suspend the solids and make them
`appear to behave as a liquid. This process is usually referred to as fluidization.
`The most common fluid bed is the gas-_fluidized bed. With gas feeds, the excess
`gas over the minimum required for fluidization rises as discrete bubbles, through
`which the surrounding solids circulate. At higher gas rates, such beds lose their
`clearly defined surface, and the particles are fully suspended. Depending on the
`circumstances, these reactors are variously called riser, circulating-fluidized,
`fast-fluidized, or entrainment reactors. In ebullating-bed or gas—liquid—solid
`reactors, the solids are fluidized by liquid and gas, with gas primarily providing
`lifting power in the former, and liquid in the latter. These become slurry bubble
`column reactors (less precisely, slurry reactors) at higher rates when the beds
`begin to lose their defined surfaces. Slurry bubble column reactors that contain
`finely powdered solids are often termed and treated as bubble column reactors
`because such suspensions are homogeneous.
`A reactor is termed a radial or panel-bed reactor when gas or Vapor flow
`perpendicular to a catalyst-filled annulus or panel. These are used for rapid
`reactions to reduce stresses on the catalyst or to minimize pressure drops. Similar
`cross-flow configurations also are used for processing solids moving downward
`under gravity while a gas passes horizontally through them. Rotary kilns, belt
`dryers, and traveling grates are examples. Cross-flow reactors are not restricted
`to solids-containing systems. Venturis, in which atomized liquids are injected
`across the gas stream, are effective for fast reactions and similarly for generating
`small gas bubbles in downward-flowing liquids where mass transport across the ,
`gas—liquid interface is limiting.
`Flow Regimes in Multiphase Reactors. Reactant contacting, product separa-
`tions, rates of mass and heat transport, and ultimately reaction conversion and
`product yields are strong functions of the gas and liquid flow patterns within
`the reactors. The nomenclature of commonly observed flow patterns or flow
`regimes reflects observed flow characteristics, ie, annular, bubbly, plug, slug,
`spray, stratified, and wavy.
`Multiphase reactor flow regimes depend on both physical properties, eg,
`density, viscosity, and interfacial tension, and hydrodynamic and gravitational
`‘forces exerted on fluids. Mechanistic models, eg, those describing the annu-
`lar mixed-phase flow between fixed-bed catalyst pellets as analogous to flow
`
`Page 11 of 12
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`

`
`1014
`
`REACTOR TECHNOLOGY
`
`A
`
`_
`
`Vol. 20
`
`through two-dimensional slits, are emerging for predicting phase boundaries be-
`tween regimes (5). However, flow maps, generally designed for specific reactor
`types, operating conditions, and fluid combinations are most commonly used to
`depict gas and liquid flow rates associated with various flow regimes and to
`delineate the phase (6).
`
`Reactor Selection
`
`T
`
`Selection of a reactor, whether for a new application or a changing situation,
`is often determined by economics, reliability, or availability of a proven system
`that is amenable to extension in a new service. For example, fixed beds and
`slurry reactors are favored at high pressures over fluid beds, fluidized systems
`are less likely to develop hot spots or be subject to temperature runaways, and
`downflow vapor-phase fixed-bed technology originally developed for desulfur-
`izing vaporized naphthas and light gas oils has been extended to mixed-phase
`operation with higher boiling gas oils and residua. Introduction of new catalysts,
`improvements in process and equipment design and operations, transient reactor
`behavior, heat generation and removal, reduced emissions and waste minimiza-
`tion, and safety-related hazards are other issues that influence the continued
`and extended use of a reactor configuration.
`—
`Catalyst Development. Traditional slurry polypropylene homopolymer
`processes suffered from formation of excessive amounts of low grade amorphous
`polymer and catalyst residues. Introduction of catalysts with up to 30-fold higher
`activity together with better temperature control have almost eliminated these
`problems (7). Although low reactor volume and available heat-transfer surfaces
`ultimately limit further productivity increases, these limitations are less restric-
`tive with the introduction of more finely suspended metallocene catalysts and
`the emergence of industrial gas-phase fluid-bed polymerization processes (see
`METALLOCENE CATALYSTS (SUPPLEMENT)).
`\
`Design and Operations Improvement. Process improvements may per-
`mit older reactor types to remain competitive and slow displacement by other
`technological advances. Fluid catalytic cracking (FCC) reactors (8) evolved from
`long-residence time fluidized beds, designed for processing atmospheric gas oils,
`to short-contact time riser reactors capable of handling metals-laden vacuum gas"
`oils and residua; feeds are more readily processed using hydrogen at high pres-
`sures, although at higher cost. Improvements in feed injectors and termination
`zone configurations (where product is separated from catalyst and further reac-
`tions quenched) heat and pressure balance control, solids retention, and mechani-
`cal reliability are essential in achieving higher conversion levels and increased
`yields of desired products made possible by the development of zeolite catalysts.
`These enhancements have been incorporated into both new and existing units.
`The introduction of highly active zeolites plays a dominant role, but catalyst
`superiority is not sufficient by itself.
`Heat Generation and Removal. The impact of heat generation and re-
`moval on kinetics similarly affects reactor selection criteria. Problems of maxi-
`mizing outputs from exothermic or endothermic reactions occur with reversible
`reactions, eg, ammonia synthesis or water gas shift reactions; temperature se-
`
`A
`
`A
`
`3
`
`.
`
`I
`
`It
`
`i
`
`i
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`Page 12 _ofi12
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`Page 12 of 12