Channelling is most severe

(A) In towers packed with stacked packing

(B) In towers packed randomly with crushed solids

(C) In dumped packing of regular units

1 Answer

Answer :

(A) In towers packed with stacked packing

Related questions

Description : Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the (A) Packing may be crushed due to thermal expansion/contraction of the ... C) Viscosity variation of the fluids may cause channelling/flooding (D) None of these

Last Answer : (A) Packing may be crushed due to thermal expansion/contraction of the components of the equipments

Description : In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter (A) > 4 :1 (B) < 8 : 1 (C) > 8:1 (D) < 6:1

Last Answer : (C) > 8:1

Description : Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the ... of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres

Description : Which of these columns incurs the lowest pressure drop? (A) Packed column (with stacked packing) (B) Packed column (with dumped packing) (C) Bubble plate column (D) Pulse column

Last Answer : (A) Packed column (with stacked packing)

Description : Stacked packing compared to dumped packing (A) Provides poorer contact between the fluids (B) Gives lower pressure drop (C) Both (A) and (B) (D) Gives higher pressure drop

Last Answer : (C) Both (A) and (B)

Description : Channelling in a packed tower results from the (A) High pressure drop (B) Maldistribution of liquid (C) Non-uniformity of packing (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Description : Very tall packed towers are divided into series of beds to (A) Reduce the overall pressure drop (B) Avoid channelling (C) Reduce liquid hold-up (D) Avoid flooding

Last Answer : (B) Avoid channelling

Description : The main reason for dividing a tall packed tower into series of small towers is to (A) Minimise the overall pressure drop (B) Avoid flooding (C) Reduce liquid hold up (D) Avoid channelling

Last Answer : (D) Avoid channelling

Description : Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) (A) Increases pressure drop, increases surface area (B) Increases pressure drop, decreases ... (C) Decreases pressure drop, increases surface area (D) Decreases pressure drop, decreases surface area

Last Answer : (C) Decreases pressure drop, increases surface area

Description : In an absorption column, the flooding velocity for random packing is __________ that for stacked/regular packing. (A) Greater than (B) Smaller than (C) Equal to (D) Either (A), or (B); depends on the type of packing

Last Answer : (B) Smaller than

Description : In a packed bed absorption column, the channelling will be noted by the (A) Increase in flow rate (B) Sharp drop in pressure drop (C) Sharp rise in pressure drop (D) None of these

Last Answer : (B) Sharp drop in pressure drop

Description : For a packed bed reactor; the presence of a long tail in the residence time distribution curve is an indication of: (A) Ideal plug flow (B) Bypass (C) Dead zone (D) Channelling

Last Answer : (C) Dead zone

Description : Which of the following same diameter columns gives lowest pressure drop per unit height? (A) Bubble-cap column (B) Sieve-plate column (C) Packed column (stacked)

Last Answer : (C) Packed column (stacked)

Description : The optimum moisture content in solids to be crushed/ground ranges from __________ percent. (A) 3 to 4 (B) 8 to 10 (C) 10 to 15 (D) 15 to 20

Last Answer : (A) 3 to 4

Description : Pressure drop through plate tower as compared to that through packed tower, for the same duty will be (A) Less (B) More (C) Equal (D) Either (A) or (B); depends on the packing height

Last Answer : (B) More

Description : Out of the following, the lowest packing of atoms exists in __________ crystal lattice structure. (A) Hexagonal close, packed (hcp) (B) Face centred cubic (fcc) (C) Body centred cubic (bcc) (D) Simple cubic

Last Answer : (D) Simple cubic

Description : Which of the following liquid-vapor contacting devices provides maximum contact surface area for a particular duty? (A) Sieve plate column (B) Bubble cap column (C) Randomly packed column (D) Wetted wall column

Last Answer : (D) Wetted wall column

Description : With increase in the liquid flow rate at a fixed gas velocity in a randomly packed counter current gas-liquid absorption column, the gas pressure drop (A) Decreases (B) Remains unchanged (C) Increases (D) Decreases exponentially

Last Answer : (C) Increases

Description : Pick out the correct statement. (A) Fanning friction factor is inversely proportional to Reynolds number always (B) The property of a randomly packed bed (with raschig rings) is given by the ratio of the ... the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow

Last Answer : (D) Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow

Description : Which of the following equipments is not used in liquid-liquid extraction? (A) Pachuka tank (B) Agitated vessels (C) Centrifugal extractors (D) Packed towers

Last Answer : (A) Pachuka tank

Description : Which of the following equipments is not used for liquid dispersion? (A) Wetted wall towers (B) Packed towers (C) Venturi scrubbers (D) Agitated vessels

Last Answer : (D) Agitated vessels

Description : Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given L/V' ratio (B) The extraction per unit ... and its cross￾section is wider at the bottom (D) Vander wall adsorption is also called chemisorption

Last Answer : (D) Vander wall adsorption is also called chemisorption

Description : The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives (A) Low pressure drop and high hold up (B) High pressure drop and low hold ... C) Low pressure drop and low hold up (D) High pressure drop and high hold up

Last Answer : (C) Low pressure drop and low hold up

Description : Use of packed towers for distillation is generally limited to the (A) Small sizes (B) Multi-component distillation (C) High pressure operation (D) Vacuum distillation

Last Answer : (A) Small sizes

Description : Which one of the following devices is not used for both the absorption as well as the liquid-liquid extraction processes? (A) Packed towers (B) Plate towers (C) Spray towers (D) Wetted wall columns

Last Answer : (D) Wetted wall columns

Description : (1) they contain free electrons Explanation: Metals typically consist of closepacked atoms, meaning that the atoms are arranged like closely packed spheres. Two packing motifs are common, one ... surrounded by six neighboring atoms. Several metals adopt both structures, depending on the temperature.

Last Answer : Helium gas is filled in ballons because (1) its atomic number is 2 (2) it is lighter than air (3) it is one of the constitutents of water (4) it is a noble gas

Description : __________ column is the most suitable for achieving the best performance for mass transfer operations involving liquid with dispersed solids. (A) Wetted wall (B) Packed (C) Plate (D) Spray

Last Answer : C) Plate

Description : A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream

Last Answer : (A) Incurs smaller pressure drop

Description : What are the benefits of a stacked washer and dryer over separate units?

Last Answer : A stacked washer-dryer unit save a lot of space. The unit is narrower than a conventional washing machine. By sitting the dryer on top of the washer, less floor space is needed, which is excellent for small spaces, like apartments and houses in which laundry space is at a premium.

Description : A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle ... fluidisation velocity, VOM is (A) 12 mm/s (B) 16 mm/s (C) 24 mm/s (D) 28 mm/s

Last Answer : (B) 16 mm/s

Description : A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system ... What is the porosity of the fluidised bed? (A) 0.2 (B) 0.5 (C) 0.7 (D) 0.8

Last Answer : (C) 0.7

Description : The following are true about the cornea: a. the stroma contains collagen fibrils of regular thickness b. the Bowman's layer contains randomly arranged collagen fibrils c. the Bowman's layer is the ... layer of the epithelium d. type I collagen is the main type of collagen found in the cornea

Last Answer : type I collagen is the main type of collagen found in the cornea

Description : Randomly assigning treatment to experimental units allows: a. population inference b. causal inference c. both types of inference d. neither type of inference

Last Answer : b. causal inference

Description : A liquid substance _______. A. has particles packed tightly together B. has definite volume C. has definite shape D. has particles arranged in a regular pattern?

Last Answer : has definite volume

Description : The work index in Bond's law for crushing of solids has the following dimensions (A) No units (dimensionless) (B) kWh/ton (C) kW/ton (D) kWh.m1/2 /ton

Last Answer : (B) kWh/ton

Description : In patients receiving massive blood transfusion for acute blood loss, which of the following is/are correct? A. Packed red blood cells and crystalloid solution should be infused to restore oxygen ... should be administered with every 5 units of packed red blood cells to avoid hypocalcemia.

Last Answer : Answer: A DISCUSSION: Patients who are suffering from acute blood loss require crystalloid resuscitation as the initial maneuver to restore intravascular volume and re-establish vital signs. If 2 to 3 liters ... when the infusion of blood proceeds at a rate exceeding 1 to 2 units every 5 minutes

Description : Cooling towers vary in size from small roof-top units to very large hyperboloid structures that can be up to ____meters tall and _____ meters in diameter, or rectangular structures that can be over 40 meters tall and 80 meters long. a. 200&100 b. 100&50 c. 200&50 d. 200 &150

Last Answer : 200&100

Description : Cooling towers vary in size from small roof-top units to very large hyperboloid structures that can be up to ____ meters tall and _____ meters in diameter, or rectangular structures that can be over 40 meters tall and 80 meters long. a. 200&100 b. 100&50 c. 200&50 d. 200 &150

Last Answer : a. 200&100

Description : _______ cooling towers use a process similar to the one found in small evaporative cooling units. a. Hyperboloid b. Tower c. Condensate loop d. None

Last Answer : a. Hyperboloid

Description : Which cooling Towers use a process similar to the one found in small evaporation active cooling units a) hyperbolic b) Tower c) condensate loop d) none of these

Last Answer : a) hyperbolic

Description : Solids may be considered to be either crystalline noncrystalline. The basic difference between them is that a crystal, in contrast to a noncrystal: w) has a sharp melting point x) has an irregular array of atoms y) exhibits double refraction z) has a completely regular atomic or molecular structure

Last Answer : ANSWER: Z -- HAS A COMPLETELY REGULAR ATOMIC OR MOLECULAR STRUCTURE

Description : What structural units up network solids?

Last Answer : Nonmetal atom

Description : During sewage treatment, effluent from which one of the following treatment units has minimum wt/vol amount of suspended solids? (a) Detritus channel (b) Primary sedimentation tank (c) Secondary sedimentation tank (d) Activated sludge process aeration tank

Last Answer : (d) Activated sludge process aeration tank

Description : any suggestions on buying a washer/dryer set? stacked vs. side-by-side?

Last Answer : stacked may be smaller. The best is a front-loading washer. They use less fuel & water & clean better.

Description : how to create a stacked form with CSS and HTML ? -How To ?

Last Answer : answer:

Description : What is Two stacked numbers appearing after a clef sign?

Last Answer : It's called a "time signature." The top number indicates howmany beats per measure, and the bottom number specifies theduration of note that gets one beat.

Description : Does Lowe's sell the stacked washer and dryer combo I am moving to a tiny apartment and I want a new set, not used.?

Last Answer : Lowe's offers a stackable unit by Whirlpool for around $1300. The unit is available in white only, and features a 2.6 cubic foot washer and a 5.9 cubic foot gas dryer.

Description : How much room does a stacked weight machine take up?

Last Answer : 14 by 14 square foot will be plenty of space.

Description : Where can I get the best deal on a stacked washer and dryer online?

Last Answer : You can I get the best deal on a stacked washer and dryer online by going to either of the folllowing websites www.ebay.com or www.Amazon.com for low prices

Description : Where can I purchase stacked washer dryer online?

Last Answer : In order to get and properly stack a stacked washed dryer one must first get a traditional model of these original specimens and then analyze it and record.