140:
The packing will appear to not be working properly. The height equivalent to a theoretical plate (HETP) will be greater than expected. The problem is not the packing itself but the mal-distribution of the fluids entering the packed bed. These columns can contain liquid distributors and redistributors which help to distribute the liquid evenly over a section of packing, increasing the efficiency of the mass transfer. The design of the liquid distributors used to introduce the feed and reflux to a packed bed is critical to making the packing perform at maximum efficiency.
30:
20:
175:, gas-phase, catalytic reactions. The advantages of using a packed bed reactor include the high conversion of reactants per unit mass of catalyst, relatively low operating costs, and continuous operation. Disadvantages include the presence of thermal gradients throughout the bed, poor temperature control, and difficult servicing of the reactor.
139:
required to make a given separation is calculated using a specific vapor to liquid ratio. If the liquid and vapor are not evenly distributed across the superficial tower area as it enters the packed bed, the liquid to vapor ratio will not be correct and the required separation will not be achieved.
143:
Packed columns have a continuous vapor-equilibrium curve, unlike conventional tray distillation in which every tray represents a separate point of vapor-liquid equilibrium. However, when modeling packed columns, it is useful to compute a number of theoretical plates to denote the separation
132:), which is beneficial while operating under vacuum. Differently shaped packing materials have different surface areas and void space between the packing. Both of these factors affect packing performance.
123:
to take complicated paths through the bed (creating a structured packed bed). In the column, liquids tend to wet the surface of the packing material and the vapors pass across this wetted surface, where
144:
efficiency of the packed column with respect to more traditional trays. In design, the number of necessary theoretical equilibrium stages is first determined and then the packing height equivalent to a
234:
are used to quantify liquid distribution patterns in packed columns; choice of tomographic technique depends on the primary measurement of interest, randomness of packing, safety requirements, desired
128:
takes place. Packing materials can be used instead of trays to improve separation in distillation columns. Packing offers the advantage of a lower pressure drop across the column (when compared to
202:
The Ergun equation, while reliable for systems on the surface of the earth, is unreliable for predicting the behavior of systems in microgravity. Experiments are currently underway aboard the
135:
Another factor in performance, in addition to the packing shape and surface area, is the liquid and vapor distribution that enters the packed bed. The number of
214:
The performance of a packed bed is highly dependent on the flow of material through it, which in turn is dependent on the packing and how the flow is managed.
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84:
material until the packing is hot. Air or other cool gas is then fed back to the plant through the hot bed, thereby pre-heating the air or gas feed.
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consisting of a tube filled with packing material can also be called packed columns and their structure has similarities to packed beds.
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227:
231:
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49:, pipe, or other vessel that is filled with a packing material. The packed bed can be randomly filled with small objects like
626:"Experimental Study on Liquid Spread and Maldistribution in the Trickle Bed Reactor Using Electrical Resistance Tomography"
268:
57:. Packed beds may also contain catalyst particles or adsorbents such as zeolite pellets, granular activated carbon, etc.
575:"Liquid distribution and hold-up measurement in counter current flow packed column by electrical capacitance tomography"
152:(HETP), is also determined. The total packing height required is the number theoretical stages multiplied by the HETP.
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172:
573:
Wu, Hao; Buschle, Bill; Yang, Yunjie; Tan, Chao; Dong, Feng; Jia, Jiabin; Lucquiaud, Mathieu (2018-12-01).
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The column bed can be filled with randomly dumped packing material (creating a random packed bed) or with
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in chemical plants. In this case, hot gases are allowed to escape through a vessel that is packed with a
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101:
574:
535:
415:
493:
392:
536:"Liquid flow texture analysis in trickle bed reactors using high-resolution gamma ray tomography"
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Schubert, Markus; Hessel, Günther; Zippe, Cornelius; Lange, Rüdiger; Hampel, Uwe (2008-07-01).
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can be used to predict the pressure drop along the length of a packed bed given the fluid
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61:
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Eda, Takeshi; Sapkota, Achyut; Haruta, Jun; Nishio, Masayuki; Takei, Masahiro (2013).
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455:"Modelling of multiphase flow in packed beds by computer-assisted x-ray tomography"
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to collect data and develop reliable models for in-orbit packed-bed reactors.
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A hollow object filled with material that does not fully obstruct fluid flow
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The purpose of a packed bed is typically to improve contact between two
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642:
416:"Tomographic measurement of breakthrough in a packed bed adsorber"
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in a chemical or similar process. Packed beds can be used in a
414:
Salem, Karijm; Tsotsas, Evangelos; Mewes, Dieter (2005-01-01).
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is known as a packed column. Columns used in certain types of
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Toye, D; Marchot, P; Crine, M; L'Homme, G (1996-03-01).
258:
Pages displaying short descriptions of redirect targets
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Pages displaying wikidata descriptions as a fallback
256: – Relation used in the field of fluid dynamics
602:20.500.11820/ac4eaca9-e1ee-4908-bbf9-970328f64eb8
119:sections, which are arranged in a way that force
76:, but packed beds have also been used to store
163:are reactor vessels containing a fixed bed of
333:Seader, J.D. & Henley, Ernest J. (2006).
295:Perry, Robert H. & Green, Don W. (1984).
271: – company in Manchester, United Kingdom
8:
337:(2nd ed.). John Wiley & Sonstahm.
53:or else it can be a specifically designed
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360:Elements of Chemical Reaction Engineering
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150:height equivalent to a theoretical plate
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18:
391:. Glenn Research Center. Archived from
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167:material, they are widely used in the
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298:Perry's Chemical Engineers' Handbook
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630:Journal of Power and Energy Systems
506:10.1016/b978-1-78242-118-4.00007-1
459:Measurement Science and Technology
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232:electrical resistance tomography
362:(4th ed.). Prentice Hall.
500:, Elsevier, pp. 197–222,
1:
335:Separation Process Principles
301:(6th ed.). McGraw-Hill.
269:Industrial Tomography Systems
146:theoretical equilibrium stage
92:A packed bed used to perform
579:Chemical Engineering Journal
540:Chemical Engineering Journal
420:Chemical Engineering Science
250: – Form of distillation
191:, the packing size, and the
265: – Physical phenomenon
204:International Space Station
685:
156:Packed Bed Reactors (PBRs)
592:10.1016/j.cej.2018.07.016
552:10.1016/j.cej.2007.10.006
471:10.1088/0957-0233/7/3/027
432:10.1016/j.ces.2004.08.013
358:Fogler, H. Scott (2006).
169:chemical process industry
171:and find primary use in
492:Johansen, G.A. (2015),
248:Continuous distillation
494:"Gamma-ray tomography"
254:Kozeny-Carman equation
228:electrical capacitance
34:
26:
498:Industrial Tomography
283:Random column packing
32:
22:
389:Space Flight Systems
94:separation processes
395:on 5 September 2015
218:techniques such as
161:Packed bed reactors
39:chemical processing
24:Super-Raschig rings
669:Chemical equipment
238:rate, and budget.
137:theoretical stages
117:structured packing
55:structured packing
35:
33:Structured packing
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643:10.1299/jpes.7.94
515:978-1-78242-118-4
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199:of the fluid.
185:Ergun equation
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110:chromatography
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72:process, or a
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9:
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263:Fluidized bed
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226:, gamma ray,
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173:heterogeneous
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51:Raschig rings
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25:
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664:Distillation
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519:, retrieved
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397:. Retrieved
393:the original
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289:Bibliography
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114:
106:distillation
91:
88:Applications
70:distillation
59:
45:is a hollow
42:
36:
585:: 519–532.
399:13 December
278:Dixon rings
216:Tomographic
658:Categories
521:2023-10-22
317:References
210:Monitoring
98:absorption
96:, such as
82:refractory
43:packed bed
611:1385-8947
560:1385-8947
479:0957-0233
440:0009-2509
193:viscosity
165:catalytic
102:stripping
242:See also
189:velocity
74:scrubber
197:density
609:
558:
512:
477:
438:
385:"PBRE"
366:
341:
305:
179:Theory
121:fluids
104:, and
62:phases
224:x-ray
607:ISSN
556:ISSN
510:ISBN
475:ISSN
436:ISSN
401:2015
364:ISBN
339:ISBN
303:ISBN
195:and
183:The
78:heat
68:, a
47:tube
41:, a
638:doi
597:hdl
587:doi
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548:doi
544:140
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
