CA1039477A - Process for fluidized contact - Google Patents

Abstract

ABSTRACT

A process for fluidized contact which comprises contacting a liquid or a mixture of a liquid and a gas intimately with solid particles. More specifically, the process comprises introducing a porous packing into at least a part of a contact zone to form a porous packed bed, then introducing solid particles into the lower part of the contact zone, feeding a liquid or a mixture of a liquid and a gas (to be referred to as a "fluid") from the lower part of the contact zone to form a fluidized bed of the solid particles, where-by the fluid is contacted intimately with the solid particles within the contact zone and the fluidized porous packed bed. In the process, the ratio of the superficial volume occupied by the porous packed bed to the real volume of the porous packing is adjusted to at least 1.3, and the ratio of the average pors diameter of the pores of the porous packing to the average particle diameter of the solid particles is adjusted to 1.1 to 10Ø The process is suitable for use, for example, in physical treatment processes such as absorption and drying, and in chemical treatment processes such as alkylation of hydrocarbons

Description

3~ 7 FILED OF THE ~rVENTION
~ his invention relates to a process for fluidized contact which comprises contacting a liquid or a mixture of a liquid and a gas intimately with solid particles. More specifically, this invention relates to a process which comprises introducing a porous packing into at least a part of a contact zone to form a porous packed bed, then introducing solid particles into the lower part of the contact zone, feeding a liquid or a mixture of a liquid and a gas (to be referred to as a "fluid") from the lower part of the contact zone to form a fluidized bed of the solid particles, whereby the fluid is contacted intimately with the solid particles within the contact zone and the fluidized porous packed bed.
BACKGROUND OF THE INVENTION
Many proposals have been made to contact a liquid or a mixture of a liquid ànd a gas with solid particles~
~hese proposals were made, for example, in Japanese Patent Publications Nos~ 26105/~8 and 29162/720 Japanese Patent Publication No. 26105/68 discloses that when solid particles are placed in a contacting vessel, and a fluid is introduced into the vessel from its lower parts, the layer of the solid particles expands from its initially packed state, and the solid particles make a ~ubsta~ti~l motion, behaving as if they were a liquid. The fluidized bed is formed usually depending upon the specific gravity of the particles, their size, the amount of the particles accomodated7 and the flow rate of the fluid. Furthermore, Japanese Patent Publication No. 29162/72 contemplates the \.

3g477 improvement of the contact between a fluid and solid particles by providing an inside cvlindrical body w-ithin a contact-ing vessel and thus circulating the solid particles regularly.
Contacting of a fluid w;~th solid particles utilizing fluidized beds as mentioned above is a superior expedient because it can ensure intimate and uniform con-tact. Furthermore, according to methods of this type, the solid particles can be exchanged while the contact between the fluid and the solid particles is continued~
This is a characteristic not seen in fixed-bed methodsD
However, the fluidized state of solid particles is essential-ly dominated by the flow rate of the fluid since the fluidized bed method usuallv comprises introducing a fluid from the lower part of a contacting vessel, contacting the solid particles with the fluid while fluidizing the solid particles within the contact vessel, and then with-drawing the fluid from the vesselO If the flow rate of the fluid is too low, the solid particles cannot be filuidized uniformly, and therefore, the contact is non-uniformO Furthermore, when the flow rate of the fluid exceeds a certain limit, the stability of the fluidized bed is rapidly destroyed~ and the solid particles flow out of the system by being carried on the fluido Especially when the fluid contains the ~ubbles, the interfaces of the bubbles interfere with the solid particles, and the bubbles entrain the solid particles irrespective of the flow rate of the fluid, so that the fluidized bed becomes very unstable.
Generally, the smaller the size of solid particles, P~39~L77 the larger is the area of contact, and the more intimate is the contact between the solid particles and a fluid, but there is a stronger tendency that the solid particles flow out of the contacting vessel. In such a case, measures are taken to feed the solid particles as a slurry in the fluid to be treated, withdrawing the solid particles as a slurry in the fluid, and allow~ng the slurry to stand in a separate vessel thereby to separate the solid particles from the fluid.
SUMMARY OF THE INVENTION
It is an object of this invention to remedy the defects of the known fluidized beds, and to provide a process for fluidized contact wherein solid particles can be maintained in a dense fluidized sta~e with very good stability, and the f`low-out of solid particles from the contacting vessel is reduced to a minimum.
According to this invention, there is provided a process for fluidized contact by contacting a fluid selected from the group consisting of a liquid and a mixture of a liquid and a gas, said gas being in the form of fine bubbles uniformly distributed throughout the liquid, intimately with solid particles in a contacting vessel which comprises forming a porous packed bed in at least a part of a contact zone of said contacting vessel by filling the contact zone with a porous packing, accommodating the solid particles in the lower part of the contact ~one, intDoducing the fluid from the bottom of the contacting vessel to form a fluidized layer of the solid particles within the contact zone, the upper end of the layer of the solid particles expanded by the fluidization being located within the porous packed bed, and withdrawing the fluid which has made contact from the upper part of the contacting vessel, said contact being performed under the following conditions:
(1) the ratio of the superficial volume occupi~d by the porous packed bed to the real volume of the porous packing is at least 1.3, and ~.-~39~77

(2) the ratio of the average pore diameter of the pores of the porous packing to the average particle diameter of the solid particles is 1.1 to o.o.
The above porous packed bed may be formed over the entire contactzone. However, in one preferred embodiment of the process of this invention, it is formed only at the upper part of the contact zone, in which case the ratio of the length of the contact zone to that of the porous packed bed is within the range ofll.5 to 5.0, preferably 2~0 to 4Ø
BRIEF DESCRIPTION OF THE DRA~INGS
Figure 1 is a simplified cross-sectional view of one example of a contacting vessel used in this invention in which a porous packed bed is formed over the whole of a contact zone;
Figure 2 is a simplified cross-sectional view of another example of a contacting vessel used in this invention in which a porous packed bed is formed only in the upper part of a contact area; and Figure 3 shows a porous Raschig as one example of the porous packing used in this invention.
DETAILED DES_RIPTION OF THE INVEN ION

r~ - 5 _ ~LID3~477 The packing used in this invention to form a packed bed should be porous. For example, a porous sheet containing a number of small pores or a net having a suitable mesh size is made into a small object of a suitable size, and a number of such small objects are used as the porous packing in accordance with this inventionO
The porous R~SChig ring illustrated in Figure 3 is a preferred porous packing used in this inventionO
The shape of a porous packing piece used in this invention may be any desired one~ such as a cylindrical, ring-like, net-like, coil-like or star-like shapeO The material for the porous packing may be any suitable material to be chosen according to the contacting conditionsD Examples of the material are refractory inorganic substances such as mctals, porcelain Glay, silica, alumina or magnesia, and polymeric compounds such as polyetlylene, pol~propylene, polyvinyl chloride or polytetrafluoroethylerleO
~ he term contact zone", as used in the present specification and claims, denotes a zone where the fluidized contact of a fluid with solid particles is effected~ In the contacting vessels shown in Figures 1 and 2, the areas with a length L are what are called contact zones in the present application.
- ~he length of the porous packed bed shown in Figure 1 is equal to L, and in Figure 2, it is L3~
The term "real volume of a porous packing", as used in the present specification and claims, denotes the volume which is occupied only by the porous packing used in this invention. On the other hand, the volume which is ~039~77 occupied by a geometrical contour of the packing will be referred to in this application as ;'the bulk volume of a packing'.
This will ~e specificall~-~ e~plained with regard to the porous Raschig ring shown in Figure 3 as an example.
~he "real volume of the porous packing" is then the volume which is occupied only by the porous sheet which constitutes the porous Raschig ring, and the "bulk volume of the pack-ing" is equal to the volume of a c~linder which is a con-tour of the Rasching ring (the volllme being ~r2h whereinr is the outside diameter of the cylinder, and h is its height)O
The term "superficial volume ^ccupied by a porous packed bed", as used in the present specification and claims, denotes the volume ~rhich is occupied in space by a porous packed bed formed as a result of filling a porous packingO This volume is equal to the sum total of the bulk volume of all the entire packing pieces and the volume of the space among adjacent packing piecesO
~he superifical volume occupied by a porous packed bed is ~4 D2L in Figure 1, and ~4 D2L3 in Figure 20 D is th~ inside di~meter of the contacting vessel (cylindrical)O
The term ~! average pore diameter of a porous pack-ing", as used in the present specification and claims, is a measure of the size of the pores of the porous packing, and defnied as the diameter of a circle ~rhich has an area equal to an average value of the areas of the porous packing. ~nleret~ porous packing is a Raschig ring made of a porous sheet such as sho~^rn in Figure 3, the average ,. '''" , ""~

1~39~77 area of the pores should be calculated only on the basis of the areas of the pores provided on the porous sheet as a material, and the areas of the top and bottom surfaces of the cylindrical Raschig should not be incorporated in this calculationO Likewise, ~.Then the porous packing is made of a net, the average area of the pores should be calculated only from the areas of the meshes of the net. When the porous packing used in this invention is a coily packing, the space between lines forming the coil is regarded as a pore of the porous packing~ and the average pore diameter is defined as an average value of the areas of the these spacesO
The solid particles to be contacted wlth fluids in the present invention assume various shapes, f~r example, spheres, or pellets, or cylindrical shapes (in the case of extrusion-molded solid particles)O
In view of this, the "average particle diameter of solid particles', as used in the present specification and claims t iS regarded as a measure of an average size of the particles irrespective of their shape, and defined as the diameter of a sphere having a volume equal to the average volume of the solid particles~
The present invention i~ based on the discovery that when the ratio of the superficlal volume occupied by a porous packed ~bed to the real volume of a porous pac~ing is adjusted to at least 1.~, and the ratio of the average pore diameter of the pores of the porous packing to the average particle diameter of solid particles is adjusted to 1.1 - 10.0 in the process of contacting a ~)39~7~
fluid with solid particles by forming a fluidized bed of the solid particles in the porous packed bed formed in at least a part of a contact zone, the motion of the solid particles can be properly controlled so that thet ~ain ~In~
'~h 5 contact between the fluid and the solid particles is ~ r.c~
very uniform and stable and the flow-out of the solid par-ticles from the contacting vessel is reduced to a minimu~0 ~ he outstanding feature of the contacting method in accordancc with the present invention over the conven-tional contacting methods using fluidized beds is that ; the expansion of the solid particles can be reduced to a very low level, and the.refore, the concentration of the solid particles can be increasedO Increasing the concentration of the solid part;icles is of utmost significance in reac-a~ Qn~ ~OL~ S
tion and chemical engineering, and results in an ~ en~f~g-contact between fluids and solid particlesO Furthermore7 since the expansion of solid particles can be stably and markedl~ reduced, the solid particles scarcely flow out of the contacting vessel, and no special equipment is required to separate and collect the solid parti^lesO
Another great feature of this invention is exhibited ~hen a gas is present as bubbles in contacting ~ mixture of a liquid and the gas with solid particles~
With the conventionalcontacting methods using fluidized beds, bub~les are not uniforml~ distributed but tend to gather at the certral part of the contact zoneO As a result, fine bubbles as init-iall~ introduced into the contacting vessel grow into large ones as a result of gathering at the central part, and rise as large bubbles _ 9 _ ~L039~7~
in the contact zoneO When bubbles grow into large sizes, a uniform contact of liquid-gas-solid particles is greatly impeded~ and the solid particles are more liable to flow out of the contactinG vessel a~s a result of adsorption -to, and entraining by, the bubblesO Ir contast~ according to the process of this invention, bubbles are dispersed uniformly ~ and finely in the contact zone, and the tendency toward gathering at the central part can be completel~ preventedO
Conse~uently, bubbles do not grow into large sizes as i.n the converttional methods, but a uniform contact of the bubbles with the solid p?rticles can be achieved, and various troubles ascribable to the firm adsorption of the solid particles to the bubbles can be completel~J avoidedO
Accordingly, the contacting process of this ].5 invention permits a far more uniform contact between fluids and solid particles than the conventional contacting methods ~ In view of the fact tllat when a fluid contains bubbles, a uniform contact of ~he fluid with soli.d particles and the separation of the solid particles are very difficult with the conventional methods, the process of this invention is an especially advar.ttageous process for contacting a liquid,a gas, and solid particles, and separating themO
In the present invention, the ratio of the super-ficial volume occupied by the porous packed bed to the real volume of the porous packing should be at least 1O3O
If this ratio is less than 1~3, the fluidization of the solid particles becomes unstable, and the solid particles cannot be maintained in a proper fluidized state. Further-more, the real volu e of the porous packing in the porous ~03~477 packed bed becomes too large~ and consequently, the effective contact space is very much reduced~ When the porous packing is made of a wire net~ the ratio of the superficial volume occupied by the porous packtd bed to the real volume of the porous plcking can be very high, and even if this ratio is more than 100, good contact can . be maintainedO However., in view of the strength of the metallic mate~ial, the ratio is desirably not more than 100. When the porou~, pack:ing is made of a refractor~ such as porcelain clay or a polymeric compound~ the ratio is desirably not more th.~n 50 in view of the strength of the porous packingO
A cylindrical wire not can also be used as a porous packing in the present invention7 and in this case, the ratio of the superficial volume occupied by the porous packed bed to the real volume of the porous packing can - be varied over a wide range by changirlg the diameter of the cylinder while the real volume of the packing remains unchangedO It has been fol~d however that if the diameter of the cylinder is increased too much, the bulk volume of the packing becomes too large for the space among adjacent ; packing pieces, and this adversely affects the flow of the solid particles~ Thus, it is not desirable in such a case that the total bulk volume of the packing in the packed bed extremely differs from the total space among adjoining packing pieces~
Furthermore, in the present invention, it is necessary that the ratio of the average pore diameter of the pores of a porous packing to the average particle ~ 11 , 9~03~4177 diameter of solid particles should bc within the range of ~ 1.1 to 10.07 preferably 105 to 5.0~ If this ratio i5 less : than lol7 it is di~ficult for the solid particles to move freely through the pores of the porous packing~ and a uniform fluidization of the solid particles within the contacting vessel and the porous packed layer in the upper part of the contacting vessel cannot be maintainedO
On the other hand, if this ratio exceeds 10~0~ the act:ion of the porous packing to control the motion of the solid particles is reduced, and the desired fluidized state cannot be achieved, and consequently~ the flow-out of the solid particles from the contacting vessel c~nnot be preventedO
: The process of this invention should be operated so that the upper end of a layer of expanded solid particles remains within the porous packed bed. Whcn the upper end of the solid particle layer rises beyo:nd the upper end of the fluidized porous packed bed, the solid particles are ~ndesirablv entrained by the fluido According to a very preferred embodiment of the process of this invention, the porous packed bed is formed only in the upper part of thc contact zone as shown in Figure 2, and no packed bed is formed in the lower part of the contact zone. In this casc, the upper end of a fluidized bed of the solid particles is usuallv present inside the porous packed bed at the upper portion1 but for the reason given above, opcration should bc performed so that the upper end of the fluidized layer does not rise beyond the upper end of the porous packed bedO
The advanta~e of this embodiment is that an ,.

~39477 effective space for cont~.ct between solid particles and fluids can be increased in the contact zone, and the concentration of the solid particlcs within the con-tact zone can be further increased. However, i.n this embodiment, the ratio of the length of the contact zone to th2t of the porous packed bed (in Figure 2, this ratio is L:L3) should be within the range of 105 to 500, pre-: ferably within the range of 200 to 4000 If this ratio is less th~n 105, the effective contact space within the contacting vessel is reduced to narrow a space oîcontact between the solid particles and the fluido If, on the other hand, this ratio exceeds 500, the length of the porous packed bed becomcs shorter~ the action of the porous packing to control the motion of the solid particles is reduced, thus preventing an effective contact of the fluid with the solid particlcs, and especially when the fluid contains a ~as, markedlv reducing the dispersing effect of the gasO
Desirably, the average particle diameter of the solid particle.s used in this invention is usually Ool to 20~0 mmO It is also desirable that the true specific ; gravity of the soli.d particles is 1020 to 8000, and its apparent specific- gravity is OolO to 2000o ~Ihen the porous packed bed is formed in substantially the whole of the contact zone, it is desirable to adjust the ratio of the length (L) of the porous packed bed to the inside diameter (D) of the contacting vessel (L/D) to ~.0 -1500. ~en the porous packed bed is formed only in the upper part of the contact zone in order to increase ~ 15P

~)3~77 the effective contact space in the contact zone, the ratio ~I of the length (L3) of the porous packed bed to the inside diameter (D) of the contacting vessel (L3/D) is desirabl~
adjusted to 10 0-5 0 0 0 The amount of the solid particles to be fed into the contact zone desirably satisfies the following relation~
/L=0010-0070, preferably Ll/L=0O2~_0O~o L2/L Cl.0, preferably ~2/L=0O3-0O9 - L2/Ll=1Ol-4O0. preferably L2/L1=1.1--2O5 (2) wherein L is the 1ength of the contact zone; Ll is the height of a layer of solid particles when it is allo~red to st~nd; and L2 is the height of a fluidiæed bed of solid particles when they are in fluidiz.ationO
The process of this invention should desirably be performed so that the following conditions are satisfied:
- U~< U~ < 12~0 (cm/sec) (3) 0 ~ U~ ~ 800 (cm/sec~
wherein U~ is the superficial liquid velocity (based on the empty cross-section of the reactor) in the contact zone; Ug~is the superficial gas velocity (bnsed on the empty cross-section of the reactor) in the contact zone; and Uf~ is the minimum fluidizatio:n velocity of solid particles ~; 25 ~ by the liquid~
In other words, when solid particles are brought into contact only with a liquid, the process should desirably be performed so as to satisfy the formuln (3), and when contacting solid particles with a mixture of a liquid and ~Cl 3g477 a gas, the process should desirabl-J be performed so as o satisfy both of the formu~as (3) and (4)O More desirably, ihe operation is carried out so as to satisfy the following relation:
2.0(cm/sec)< U~ C 60~ (cm/sec) }
0 < Ug ~ 4O0 (cm/sec) ~ l~ the porous packed bed, the porous packing can be ~t~* either regularly or irregularly, but generally, it is preferred to fill the porous packing somewhat irregularlyO
In order to descrlbe the present inve:ntion in : f~rther details~ one specific embodiment involving a hydrodesulfurization reaction ~ill be described below by referring to the accompanying drawingsO I~ should be lmderstood however that this description does not in any way limit the present inventionO
Figure 1 shows a contacting vessel in which a porous packed bed is formed in substantially thc whole of the contact zoneO A por?us packing 2 is placed onto a porous support plate 5 (this support plate also acts as a dispersing plate) of a contacting vessel 1 having : a cylindrical shape (with an inside diameter D), thereby - to form a porous p~cked bed 3~ In Figure 1, the porous packing 2 is sho~nonly at the upper and lower portions of ~: the porous packed bed 3 for easy understanding. ~ ually, Actuall~, however, the packing pieces 2 are ~illed in the porous packed bed 3 in ~ uniform density, to for~ the porous packed ~bed having a h~ight L. In this case, the porous packed bed 3 is substanti~lly the same as a contact 20ne 6, and the length of the contzct zone ~ is equal to Lo ' 1--'"'~' ~39~77 Then, a fluid (a petroleum-type h~d.rocarbon, for example, a heavy oil) and solid particles (a desulfuriza-tion catal~st) to be contacted are placed in the lower part of the contact zoneO (~'he solid particles are not sho~m.) The length ~1 shown in Figure 1 is the height of the solid particles when they are allowed to stand~ The fluid (heavy oil) is introduced into the contacting vessel 1 through a pipe 41 passes through the dispersing plate 5, and enters the contact zon~ 6 accomodating the solid particlesO By the flowing of this fluid, the solid particles are fluidized, and as a result ? a layer of the solid particles expandsO In Figure 1, the height L2 is the hei.ght of the layer of the solid particles in the fluidized stateO In other words, when the solid particles are in the stationary state, the upper end of the layer of the solid particles Are at the height of ~1~ but as a result ris~s of fluidization, it r~sc~ to the hei~ht of L2O
Although the solid particles are fluidized and eYpand, the factor of expansion of the solid particlels can be maintained at a markedl~.r low level as compar~d with the fluidization of solid particles in a fluidiz.ed bed containing no porous packing. In other words, the porous packing used in this invention has an action of controllin~
the flowing of solid parti;cles, and as a result, a dense fluidized bed of.solid particles can be formed by the process of this inventionO The fluid (heav~ oil) to be treated ~lhich has thus contacted with the solid particles in the contact zone ~> leaves the contacting vessel 1 through a pipe 7. When the solid particles are degraded, ~)39477 they ~re withdrawn from a pipe 8, and fresh 901id particles are introduced through a pipe 90 In this case, the with-drawal and introduction of the solid particles can be performcd without vQrying the flow rate of the fluido This operation hardlv lead.s to changes in the fluidization conditionsO
Figure 2 shows the same contacting vessel 1 as in Fi~lre 1 except that the porous packed bed ~ is formed only in the upper part of the contact zone 6, and no porous packing is present in the lower part of the cont~ct zone 6. In this embodiment, tho porous packing is placed on a support plate (wire net) 10 proviAed on the upper part of the contact zone to form a porous packed bed having a height of ~2o Same as in Figure 1, a fluid is introduced 1~ into the contacting vescel 1 through pipe 4~ passes the dispersing plate 5, and enters ,he contact zone 6 to fluidize the solid particles (not shown) held on the dispersing plate 50 Since the porous packing does not exist in the lower part of the contact zone ~, the effective space capable of being utilized for a contact of the fluid with the solid particles is larger than in the case of Figure 1.
The ne~ contacting method of this invention can be applied to various processes, for example, physical treatments such as absorption, drying, ~dsortption, desorp-tion, or washing, c~nd chemical treatments such as oxidation,reduction, decomposition, polymerization or hydration, especially to the isomerization, dehydrogenation, reform-ing, or alkylation of hydrocarbons, or to the hydrogenation treatments thereof, such as hydrogenative decomposition, :~39477 hydrogenation, or hydrodesulfurizationO
The following Examples illustrate the present invention.
Examples 1 to 4 show the results of experiment., ~rhich were performed by using a contacting vessel in which a porous pc~cked bed was formed in the whole of the contact zone, and Examples 5 to 8 show the results of experiments which were performed by using a contacting vessel in which a porous packed bed was formed only in the upper part of the contact zoneO
Example 1 Experiment WAS performed under the conditions shown in ~able 1 using the same type of equipment as shown in Figure lo , E~

Table_1 _ _ _ _ __ _ __ Dimension of Height 200 cm~ dic~meter ]0 cm the contacting vessel _ _ _ _ : Porous pack- ~terial, stainless steel (.SUS 27);
5 ing (wire net) size 15 mm (diameter) x 15 ~m (height);
: . mesh 2O0 ~m x 200 mm; thickness of the wire, 005 ~m in diameterO
Solid particles Particles of a Co-Mo cat2~1yst on a silica-alumina carrier; spherical with a di~me~er of 009 mm; true specific gr~vity 30220 _ _ . __ _ L~ u d (ker_sene) : Density 00783 g/cc (20Co) fluid Viscosity 1028 x 10~2(g/cmOsecO)(20C) _s (N?~as ) Density 10165 x 10-3(g/cc) (20Co) Viscosity 1075 ~ :L0~4(g/cmOsecO)(20C) __ __ _ _ State of Height (L) of the porous packed be~
15 pac~i~ Q0 ~m; H~ight (L1) o~ thD s~lid n~r~
. la~er ~0 cm; the rat:io of the superifical . space occupied by the porous packed bed , to the real volume of` the packing=2105;
.'~ the ratio of the ~ver~e pore die~eter . of the porous pac;lring to the ~verage diametc-r of solid particles = 2022 ~.' . _ .
:~ 20 ~he experiment was conducted under the above ; conditions while introducing the liguid at a superifical velocity of 400 cm/secO and the gas (~T2 gas) at a super-ficial velocit~ of 1.0 cm/secO ~he expansion fa.ctor of . the solid particles could be reduced to below 20 0, and the fluidized state was ver~J uniform. No solid particle flowed out of the contacting vessel.
~ l~n the above experiment was conducted without using the porous p~cking7 the cxpansion factor of the solid particles incr~ased to ~bov~ ~0OO The amount of the ~L~3~77 solid particles entrained in the gRS was as much as 5%
by volume, and gas-liquid-solid separation i5 difficult.
Then, great amounts of the solid particles flowed Otlt of the contacting vesselO
~te above experinentrll reslllts show titat tne contacting process in accordance with this invention is superior.

Experiment WGtS performed under the conditions shown in Table 2 using the same equipment as in Example lo '' I ~ ~

~3947~
Tabl~ 2_ ~ .
Dimension of Hei.ght 500 cm~ diameter 2800 cm the contacting vessel ~ .
. Porou~ packing Material~ stainless steel ~SUS 27);
(a cylinderical dimension 15 mm (diameter) x 15 mm shape with 4 height, thickness 1DO mm~ pore pores) dic~meter 400 mm . _ , _ ~ ___ _. .
Solid particles Particles of a Co-Mo catalyst on the silica-alumina carrier, spherical wi-th a diameter of 102 mm9 true specific gravity 3,20 _ __ , .
Liquid (lubricant ) Density 00854(g/cc) (20Co) Properties of Viscosity 1028 (g/cmOsecO) (20Co) fluid _as (H~ ~as) Density 00089 x 10 3 (g/cc) (20Co ) Viscosity 80 0 X 10-5 (g/cmOsecO)(20cO ) ~ _ _ ~tate of Height (L) of the porous packed ~ed ~90 cm;
packing the height (Ll)`of the solid particle laye~
320 cm; the ratio of ~he superficial volume occupied by the porous packed bed to the real volume of the packing=~Ol; the ratio of the average pore diameter of the porous : packing to the average particle diameter of the solid particles=~033 . ____ ___ ......... _.. _~

The experi~e~ was conducted under the above conditions while introducing the liquid at a superficial velocity of 1200 cm/secO and the H2 gas at a superficial velocity of 301 cm/secO The expansion factor of the solid particles could-be reduced to below 104, and the fluidi~ed state was very uniformO The amount of the solid particles which flowed out of the contacting vessel was only less than 00001% by volume, which could be neglectedO
In spite of the fact that the superficial velocity of the liquid in this experiment was very severe for the operating range of the present invention, very ~ood results ~LO3~31~7 were obtainedO This demonstratcs the superiorit~ of the present inventionO
When the above experiment was conducted without using the porous packing, the expansion factor of the solid particles increased to more than ~5, and gas-liquid-solid separation became difficulto ~he amount of the solid par-ticles entrained by the gas reacted as much as 8% by volumeO

A porous packing was filled to a height of 250 cm in a contacting vessel with a height of 300 cm and a diameter of 40 cmO The porous packing was a Raschig ring made of porcelain and having a diameter of 25 mm~ . height of 25 mm and a thickness of 3 mm with 32 pores each having a diameter of 4 mmO
15Spherical solid particles of molecular sieve with an average diameter of 1 mm, a true specific gravity : of 2020, and an appar~nt specific gravity o~ 0065 were introduced into the porous packed layer to a height of 90 cmO
Naphtha containing 30 ppm of water was contacted with the molecular sieve particles in order to remove the waterO
The superficial velocity of the naphtha was adjusted to 200 cm/secS and 500 cm/secO under such a condi-tion that the ratio of the superficial volume occupied by the porous packed bed to the real volume of the porous packing was adjusted to 4, and the ratio of -the average pore diameter of the porous packing to the average particle diameter of the solid particles 7 to 40 In an~ case, the fluidized state was very uniform, and the molecular sieve particles did not at all flow outO

_ 22 -~39477 E~a ple 4 A porous packing was placed to a height of 400 cm in a contacting vessel having a height of 550 cm and a diameter of 28 cmO ~he porous packing was a Raschig ring ~ade of porcelain and having.a diameter of 25 mm., a height of 25 mm and a th.ickness of 3 mm with 32 pores with a diameter of ~ mm Spherical solid particles of molecular sieve having an average particle diameter of 105 mm~ a true speci~ic gravity of 2020 and an apparent specific gravity of 0065 were placed to a height of 200 cm in th~
porous packed bedO Naphtha containing 30 ppm of moisture and hydrogen containing 25 ppm of mositure were fed as . fluids, and contacted with the molecular sieve particles in order to remove the moisture<. ~he ratio of the super~ïcial volume occupied by the porous packed layer to the real volume of the porous packing was ad~justed to 4,and ratio of the average pore diameter of the porous packing to the average particle diameter of the solid particles, to 4O
~he superficial velocity of the naphtha was adjusted to 200 cm/secO and 5O0 cm/secO, respectively, and the superficial velocity of the hydrogen gas to 0O5 cm/secO, and 200 cm/secO, respectivelyO As a result,it was confirmed that the hydrogen bubbles were dispersed very finely, and the molecular sieve particles did not flow out of the con-tacting ves~elO
Example 5 E~periment was performed under the condi-tions shown in ~able 3 using the same equipment as illustrated in Figure 20 I Table 3 I Dimension of the Height 130 cm, diameter 8.5 cm contacting vessel Porous packing Material, stainless steel (SUS 27); dimension . 15 r,lm (diameter) x 15 mm(height), mesh 1.5 (wlre net) mm X 1.5 n~, thickness of the wire net 0.5 mm in diameter Solid Particles of R Co-Mo catalyst on a particles silica-alumina carrier; spherical Wi th a diameter of 0.65 mm; true specific gravity 3,29 Liauid (kerosene) Density 0.783 g/cc (~0 C.) Properties Viscosity 1.28 x 10- (g/cm.sec.)20C.
of the GasD(N2sigty 1 165 x 10 L(g/cc) 20 C.

I Viscosity 1.75 x 10 (g/cm.sec.)20C~

State of Height (L3) of the porous packed layer packing 3~ cm; the height (Ll) of the solid particle layer 57 cm; the ratlo of the superifical volume occupied by the porous pacl;ed bed I to the real volume of the porous pactcin~
1 20.7; the ratio of the average pore dia~eter ¦ of the porous packing to the average particle diameter of the solid particles=20.7 The experiment was conductecl under the conditions ¦ shown in Table 3 while introducing the liquid at a superflcial velocity o 3~5 cm/sec. and the gas (N2 gas) at a superficial velocity of 1.0 cm/sec. The expansion factor of the solid particles could be reduced to below 1.4. The fluidiæed state was very uniform, and the solid particles did not flow out of the contacting vessel.
~ 1hen the above experiment was performed with-out using the porous packing, the expansion factor of the solid pflrticles reached more than 2.5, and the amount ¦ of the solid particles entrained by the gas was great (8%
¦ by volumej. Gas-liquid-solid separation was difficult, ¦ and great amounts of the solid particles flowed out of the ~L~3~ 7 contacting vessel.
The ~bove experimental results can demonstrate the superiority of the contacting process of this inventionO
~xample 6 ~xperiment was performed under the conditions shown in Table 4 using the same eauipment as illustrated in.Figure 2.
Table 4 , .
Dimension Height 500 cm, diameter 2800 cm contacting . vessel . - , _ __ Porous Material, stainless steel (SUS 27);
packing dimension 20 mm (diameter) x 20 mm (height), (cylinder thickness loO mm; pore diameter 108 mm with 8 pores) .
. ~C~
1~ Solid ~ of a Co-Mo catalyst on a silica-particles alumina carriar; spherical 1~ith a diameter . of lol mm; true specific gravity 3029 ~iquid (lubricant oil) Properties Density ~,854(g/cc) 20Co O.Ui S Viscosity 1028 (g/cmOsec) 20Co Gas (H~ ~as) Density 00089 x lO 3 (g/cc) Viscosity 800 x 10~3(g/cmO secO) 20Co Height (L~) of the porous packed ~ed~ lO0 - State of cm; heigh~ of the solid particle layer 120 cm; the ratio of the superficial packin~ volume occupied by the porous packing to the real volume of the porous packing=I500;
the ratio of the average pore diameter of the porous packing to the average particle . diameter of the solid particles= 1~64 -- _ __ _ .
The experiment was ~erformed under the above-in~duci t~
mentioned conditions while ~*ff~r~ the liquid at a super-ficial v~elocit~ of lO.0 cm/sec~, and the gas (H2 gas) at a ~ velocit~J Of 2~-o cm/sec. The expansion factor ~39~77 of the solid particles could be reduced to below 105, and the fluidized state was very uniformO The amount of the solid p~rticles which flowed out of the contacting vessel was onl~y less than OoO01/~ by volume, and could be neglectedO
~ en the above experiment was conducted without using the porous pac,King, the expansion factor of the solid particles increased to above 3050 m us~ gas-liquid-solid separateion became difficult, and the amount of the solid particles entrained b~J the gas reached as much as 8,~ by volumeO
Example Z
A porous packing was filled to a height of 180 cm from the bottom of a contacting vessel with a height of ~00 cm and a diameter of 40 cm to form a porous packed bed having a height of 100 cmO The porous packing consisted of Raschig rings made of porcelain and each having a diameter o~ 25 mm, a height of 25 mm, and a thickness of ~mm with 32 pores with a diameter of 2.0 mmO
~pherical solid particles of molecular sieve having an average diameter of llmm, a true specific gravity of 2.20, and an apparent specific gravity of 0065 were placed in the contacting vessel to a height of 100 cm.
Naphtha containing 50 ppm of moisture was fed as a fluid, and contacted with the molecular sieve in order to remove the moisture.
In this experiment, the superificial velocity of naphtha was adjusted to ~.0 cm/sec., and ~.0 cm~sec., respectively, and the ratio of the superficial volume - 2~ _ `~03~477 occupied by the porous packed bed to the real volume of the porous packing was adjusted to 2.0, and the ratio of the average pore diameter of the porous packing to the average particle dic~meter of the solid particles to 24.00 In any case, the fluidized state was very uniform and the molecular sieve particles did not flo~
out of the contacting vesselO
Example 8 Hydrodesulfurization was performed using a re~ctor of the type showm in ~igure ~, and the starting oils, catalysts, reaction conditions~ and the reactor specifications shown in Tables 5, 5 and 7. The result are shown in Tables 5, 6 and 70 In any of these three runs, the catalyst particles exhibited a very stable fluidized state, and even when ; the operating conditions were changed, no substantial amounts of the catalyst particles flowed out of the reactors.
The oil and the h~Jdrogen-containing gas separated well from the catalyst particlesO ~very 40 hours or so, the catalyst particles were exchanged without stopping the operationu The steady state of the reaction remained un-changed, and no change was seen in the state of the result-ing products.
.:

Pro erties of oils Type of startlng oil ~ os- Product pheric distil-latio~ residue oil (wt.%) 4D32 1,03 zation (,~0) ~ 7600 Residual carbon 1206 7016 . content (wto%) Yield (,~ based on the material - 9504 Viscosity (csto at 50C) 97004 135~2 Asphaltene (wto%) 9~80 408 Vanadium (ppm) 81 36 Nickel (ppm3 21 12 Catal,~rst Co-Mo catalyst on a silica-alumina carrier of a spherical shape with a diameter of 009 mm and a true specific gravity of 3.220 Reaction condition.s Temperature; ~00 C0 Press~lre: 150 Kg/cm'Og LHSV (~ /hr) 1.12 Time for con-tinuous ope- 204 hours ration Amount Or oil circulated 100.0 (m3/m3) Hydrogen based on oil 953 (N m3/m3) ~03~1~77 Porous~ ckir ~ l_in) and the dim ~ on of_the reactor Ratio of the super~icial volume occu~ied b~,l the porous packed bed to 400 the real volume of the porous packing : Ratio of the average pore diameter of the porous packing to the 2 n 2 average particle diameter of the catalvst particles D lOoO cm L/D lOoO
~l/L O045 10 L2/~1 1078 L3/D . 4.0 Table 6 ~roperties ot oils_ Sta_ in~ oil Pro?uct : ~pe of startingIranian light - oil atmospheric distillation residue Total S content (wt. ~) 2036 0047 Degree of desulfuri-zation (%) - 80~1 Residual carbon content (w~ok) 6067 3.26 Yield (%) based on the material _ 95.5 Viscosit~ (cst. at136.9. 63.2 50C) Asphaltene (wt.;)1.~8 0023 Vanadiwn (ppm) 67 1' Nickel (ppm) 15 5 -- 2q --~3~477 Catalyst Co-Mo cat-alyst on a sllica-alumina carrier of a spherical shape with a diameter of 009 m~ and a true specific gravit~ of 3~220 Reaction condit~ s Temperature: 400C
Pressure: 15~ ~g/cm2Og LHSV (Q/hr) 1o41 ~ime for con-tinuous ope-ration 260 hours Amount of oil 7 ~ - -circulated 80.0 (m-~/m-) Hydrogen based ~ ~
on oil 1298 (N m /m ) Porous packin~ (~orcelain) and the _ imension of the reactor Ratio of the superficial volume occupled b~J the porous packed bed to the real volu~e of the porous packing 21.5 Ratio of the average pore diameter of the porous p~cking to the average particle diameter of : 20 the catalyst particles 1.5 D . 10.0 cm L/D 10.0 ~2/L1 1.~5 ~2~L 0.8 ~3/D 5 9~77 Table 7 ~ perties of oils_ _a tin~ oil Product ~3pe of starting oil Arabian light : vacuum distil-lation residue oil Total S content {~7t./~) 3088 0.54 Degree of desulfuri-zation (,~ 600 Residual carbon content (wto,~) 17014 7031 : Yield (%) based 92 ~
on the material - ' Viscosity (cst. at : 50C) 162406 .59306 Asphaltene (wt.%) 5054 3022 Vanadium (ppm) 50 15 Nickel (ppm) 14 8 : Catal~st Co-Mo catalyst on a silica-alumina carrier of . a spherical shape with a di~neter of 009 mm and a true .i .
specific gravity of 3.22 Reaction conditions Temperature: . 410C.
Pressure: 150 Kh/cm .g LHSV (~ hr) 0.63 25 Time for con tinuous ope-ration 390 hours Amount of oil circulated 150.0 (m3/m3) Hydrogen based 3 3 on oi.l 957 (N m ~m ) - , ''1 ~11399~77 P~rous packing (porcelain) and the dimension o~the reactor Ratio of the superficial volume occupied b~ the porous packed bed to the real volume of the porous packing 30.0 Ratio of the average pore diameter of the porous packing to the average particle di~lmeter of the catalyst particles 3O3 D . lOoO cm L/D 12~0 Ll/L 0O50 ~2/L1 1o58 ~5 '~

Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for fluidized contact by contacting a fluid selected from the group consisting of a liquid and a mixture of a liquid and a gas, said gas being in the form of fine bubbles uniformly distributed throughout the liquid, intimately with solid particles in a contacting vessel which comprises forming a porous packed bed in at least a part of a contact zone of said contacting vessel by filling the contact zone with a porous packing, accommodating the solid particles in the lower part of the contact zone, introducing the fluid from the bottom of the contacting vessel to form a fluidized layer of the solid particles within the contact zone, the upper end of the layer of the solid particles expanded by the fluidization being located within the porous packed bed, and withdrawing the fluid which has made contact from the upper part of the contacting vessel, said contact being performed under the following conditions:
(1) the ratio of the superficial volume occuped by the porous packed bed to the real volume of the porous packing is at least 1.3, and (2) the ratio of the average pore diameter of the pores of the porous packing to the average particle diameter of the solid particles is 1.1 to 10Ø

2. The process of claim 1 wherein said porous packed bed is formed in substantially the whole of said contact zone.

3. The process of claim 1 wherein said porous packed bed is formed only in the upper part of said contact zone, and the ratio of the length of the contact zone to that of the porous packed bed is within the range of 1.5 to 5Ø

4. The process of claim 1 wherein said solid particles have an average particle diameter of 0.1 to 20.0 mm.

The process of claim 1 wherein the following conditions are satisfied:
L1 /L = 0.10 - 0.70 L2/L1 = 1.1 - 4.0 L2/L < 1.0 wherein L is the length of the contact zone, L1 is the height of the solid particle layer in the stationary state, and L2 is the height of the fluidized layer when the solid particles are in the fluidized state.

6. The process of claim 1 wherein the following conditions are satisfied:
Uf? < U? < 12.0 (cm/sec.) O < U? < 8.0 (cm/sec.) wherein U? is the superficial liquid velocity in the contact zone based on the empty cross-section of the reactor, U? is the superficial gas velocity in the contact zone based on the empty cross-section of the reactor, and U? is the minimum fluidization velocity of solid particles caused by the liquid.