DE1542103A1 - Process to improve the mass transfer - Google Patents

Description

Esso Beaearch and (US 363 258 - prio 28.4.64 Engineering Company - 3417) Elizabeth. N.Y./V.3t.A. Hamburg, April 22, 1965 Ancestors to improve the mass transfer

The invention relates to a method for improving the Maasenüberganges in systems made of porous pesticides and a gas phase, especially in catalytic and Sorption processes with a gas phase consisting of at least two components. The porous material and / or the The gas phase can also contain liquid.

A way of working »in which one converts a gas phase into a. Porous zone introduces "is referred to as mass transfer or speed limited" when a use smaller porous violets or a slower flow rate of the gas phase through the porous zone leads to improved results. In the presence of liquid in the system, by improving the distribution of the liquid no corresponding improvement in results achieved.

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In many sorption and catalytic systems there is no sufficient mass transfer achieved. The previous improvement proposals are consistently associated with disadvantageous side effects. The often used increase the reaction temperature leads in catalytic systems to a decrease in the amount sorted and an increase in undesirable lifting reactions. If, on the other hand, the particle size is reduced to improve the mass transfer, this creates an increased pressure gradient across the bed. This leads to difficulties in handling the bed and increases the compression requirement and thus the costs quite considerably. In addition, it is easy with an ascending current Material lost from bed.

It has now been found that in gas / solid matter sorption processes and catalytic systems with a bed of porous particles, the mass transfer can be greatly improved if the gas is made to oscillate in the pores of the particles by rapidly changing the gas pressure over the bed. When the gas pressure rises, the gas molecules are pushed into the interior of the particle and, when the pressure falls, out of the Tellohen interior moved out

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Accordingly, according to the invention, a method for improving the mass transfer of porous substances is proposed, in which one passes a gas phase over a porous material, characterized in that one by Oscillation of the gas pressure in the pores of the porous material generates periodically changing currents.

The essence of the invention is to convert a gas phase, which preferably consists of at least two components, into a porous one Introduce zone and by oscillation of the gas pressure over the porous zone in the pores of the particles a periodic To generate inflow and outflow of the gas *

The pressure oscillation should advantageously have a frequency of 0.01 to 50,000, preferably 0.1 to 5,000 and in particular 0.25 to 25 periods per second and an amplitude of 0.000007 to 14, preferably 0.00007 to 1.4 and in particular 0.0007 to 0.14 at.

The porous material can have a pore diameter of 3 to 10, preferably have 5 to 10 * X.

The method according to the invention is particularly suitable for Molecular sieves. Natural or synthetic zeolites have a crystal structure with numerous small cavities,

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which through even smaller openings or pores of eehr of uniform size are connected to each other. These zeolites are commonly referred to as molecular sieves and are in numerous publications, for example in the work "Molecular Sieve Action of Solids" (Chemical Society »London Quarterly Reviews, Volume 3, pages 293-330, 1949) and in a book by Ch. K. Hersh, "Molecular Sieves" (Reinhold Publishing Corporation, 1961).

In the following, the invention is based on a method for separating η-paraffins from branched or aromatic hydrocarbons explained, in which the η-paraffins in an adsorption phase selectively on a Molecular sieve bed adsorbed and subsequently in a de-boron sorption phase with a displacer such as ammonia at about 20 to 315 ° C, but preferably below 205 ° C, desorbed and the ammonia by heating to 313 bis 430 ° C recovered.

In such a process for the separation of n-paraffins, the molecular sieve bed is often not sufficiently utilized. The use according to the invention of pressure oscillations during the adsorption increases the utilization the total volume of the bed improved. It is also the set is more heavily loaded with η-paraffins when one

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Single product "with a higher molecular weight, reflecting with et""Cj ₀ , used. The frequently occurring difficulty that certain η-paraffins, especially those with more than 22 carbon atoms, are not completely removed when flowing through the battery and leave the bed with the withdrawn product, can be caused by the inventive use of druocoilations in adsorption can be greatly reduced. With the application of the methods according to the invention in the case of adeorption, one of the molecular sieves is better utilized, ie more heavily loaded with η-paraffins, and secondly, in the case of single-ata products with carbon atoms τοη C ₂₂ and above that the amount of η- Paraffins reduced

When separating η-paraffins, in the adsorption stage with oscillations of a frequency of 1.5 htm 30 periods per second and an amplitude of 0.00035 hia 0.014 at and in the desorption stage with oscillations of a frequency of 0.01 to 10, preferably 0.1 to 1 periods per second and an amplitude of 0.0014 to 0.14, preferably 0.007 to 0.14 when satisfactory results were obtained,

AIa displacers become polar or polarizable Substances are used which, in comparison with dam au-

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the material has a sufficient affinity for the absorbent and sufficiently small molecules to be able to penetrate into the absorbent. In general, the displacement agent has approximately the same heat of absorption as the material to be desorbed. The displacement agents are also referred to as desorbents, displacement or desorption media. Pur the inventive method suitable Verdrängungemittel example SO _"f ammonia, carbon dioxide, alcohols containing up to be 5 Bohlen atoms such as methanol and propanol, glycols such as £ thylenglykol and Eropylenglykol, halogenated compounds such as methylene chloride, ethyl chloride, methyl fluoride, and nitrated compounds such as nitromethane and the like. The displacement agents are preferably used in the gaseous state. The preferred displacers correspond to the general formula

\ ";

wherein R ^, H «and R, are identical or different and represent hydrogen atoms or alkyl radicals having 1 to 5 carbon atoms. This includes ammonia and the primary, secondary and tertiary amines with up to 15 Bohlenetoffatomen,

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whereby ammonia and in the second place the primary amines with 1 to 3 carbon atoms, for example Xthylaain, Methylamine or butylamine, preferred are *

The desorbent can either be a displacement agent or a detergent. In the case of detergents, desorption takes place by lowering the partial pressure.

working method according to the invention can, for example, on catalytic ^ systems in hydroforming and hydrotreating » in catalytic cracking and hydrocracking as well as in the Nickel hydrogenation, ammonia synthesis, hydronitration and iron ore reduction can be used. Here you can any suitable, porous materials, for example diatomaceous earth such as kieselguhr and ifontmorillonite, or silica-aluminum oxide, bauxite, chromium oxide-aluminum oxide and Aluminum oxide can be used. Numerous other porous substances are known to the person skilled in the art.

The oscillation used according to the invention can be advantageous can be generated by three different methods. In the first method, the gas is introduced into the zone containing the porous material at a constant feed rate and the gas outflow varies periodically by means of a periodically changing restriction in the gas outlet. The second ver

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drive »means a periodically changing gas supply speed and constant gas discharge. The amount of gas increases periodically in the adsorption zone when the feed rate is increased and when it is reduced. At the third method is with constant feed rate and constant gas outflow and one connected to the bed oscillating volume worked.

The invention is explained in more detail below with reference to the accompanying drawings; show it:

1 and 2 are schematic representations of devices for carrying out the method according to the invention;

3 and 4 schematically sectioned representations

of a porous particle with a forum exit under the flow conditions with and without oscillation;

5, 6 and 7 are greatly enlarged schematic representations of two intersecting capillaries in a porous particle at normal, increased or reduced pressure;

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Pig. 8 and 10 are relationship graphs

the instantaneous to the average flow velocity versus time;

Figures 9 and 10 are graphs of adsorption

of n-faraffins with and without oscillation and

Fig. 1t is a graphical representation of the with and

BHy 'required without oscillation to achieve the same degree of desorption Amounts.

The device shown in FIG. 1 contains a bed 1 of packed porous particles, for example a molecular sieve, in particular a 5A, 10X or 13X molecular sieve, or aluminum oxide, silica gel, activated carbon or other materials known to those skilled in the art, into which gaseous material is introduced via a supply line 2 and after contact is discharged with the bed via an outlet line 3. An alternating inflow and outflow of the gaseous To achieve material in the bores of the porous particles, one of the following methods is preferably used!

In the first mode of operation, the gas is passed through the pipe introduced at a constant speed and through a

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^ß AD ORDINAL

oscillating constriction 4 in the outlet line 3 generates a periodic pressure increase in bed 1, which the periodically presses gaseous material into the porous particles. The constriction 4 oscillates gate wise an oscillation period ton about 0.005 to 100 seconds.

In the second embodiment, the gas supply into the bed 1 is controlled by an oscillating constriction 5 arranged in the line 2 and a constant gas discharge is achieved through the line 3 without the oscillating constriction 4. As a result of the periodic supply and the constant discharge, a periodic increase in pressure ± m bed 1 is also achieved.

In the third preferred embodiment of the method according to the invention, the gas supply and the gas discharge are kept constant »however the volume of one bit the bed connected zone and thus the bridge in bed 1 changed periodically. This design is illustrated in FIG. The gas occurs in the device shown there through a line 16 into a porous bed 15 and flows through a line 17. Neither line 16 nor line 17 contain an oezillating constriction. The pressure inside the bed is converted into a by a syllable 19

f »nooio / ioen ^BAD

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-M-

₁ varies with the bed 18 which _f 15 through a conduit 20 is connected "through the upward or Abviärtß bowegung dee Kolbeno 19 in the cylinder 18 resulting pressure increase or pressure reduction is in each case transferred through the conduit 20 into the bed 15 °.

method according to the invention can also be used in the case of discontinuous easier way of working, i.e. both without continuous satisfaction as well as without continuous drainage. Furthermore, liquid can also be present as long as not the entire outer surface of the porous particles is covered by a liquid film «

In the method according to the invention, an inflow and outflow is generated in the pores of the porous particles. The mode of action and the advantages of the method according to the invention lasosn The best way to do this is to use the usual mass transfer sea anions explain the transition of a component from the coherent gas phase into the interior of one of the porous Particles occur. To do this, the component must first from the gas phase into the one surrounding the individual porous particles laminar layer are transferred. The mechanism this mass excess is known and either exists from molecular diffusion or vortex diffusion. These processes, to which a pressure oscillation does not

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sen influence can be accelerated in a known manner, so that no changes are required here. Next, the component from the laminar layer must be carried to the surface of the particle itself. In the known methods, this takes place exclusively through the molecular diffusion proceeding at a low speed. According to the method according to the invention, however, a laminar layer cannot form in the classical sense, since the material directly adjacent to the surface of the particle via the pore openings alternately moves into the pore openings and material is carried from the interior of the particles to the surface. This removes an inhibition * which is often the main resistance in the conventional Maesen transition. In FIGS. 3 and 4, the elimination of the laminar layer according to the invention is shown schematically. FIG. 3 shows the classical state in which the GaamolekQle 11 move past a porous particle 13 which is enveloped by a laminar layer 12 closing the opening of a fore 14. The porous particle 13 can consist of a 5A molecular sieve deformed with a binder or any other molecular sieve or other porous substances such as aluminum oxide or silica gel. The gas molecules 11 can consist, for example, of ammonia and a long-chain n-paraffin. The laminar layer 12 is penetrated by the Qasssolecules 11 only in accordance with the slow MulekuLLTaittVtaion their nature,

FIG. 4 shows the conditions present in the process according to the invention. The periodic change in gas pressure makes one surface of the porous Particles 13 perpendicular movement of the gas molecules 11 achieved, which tears an existing laminar layer 12. When the gas pressure rises, an from the outside into the Pore 14 penetrating gas flow and with falling pressure generated from the pore 14 exiting gas stream.

According to the conventional method, the must through the laminar In the layer on the surface of the particle, the constituent reached the capillaries through further molecular diffusion penetrate the particle. In contrast, according to the invention

slow ifolecular diffusion instead of / through the alternating back and forth motion of the gas in the intersecting capillaries different

Thoroughly mixed in diameter. This

(The process is illustrated in Figures 5 to 7, which show three stages of an oscillation period. The capillary 100 shown in the figures has a considerably smaller cross section than the capillary 101. The capillary 100 contains a material designated by “x” and the capillary 101 a material labeled "o". The entire atadiura of the period shown in FIG Material χ in the narrower capillary 100 and all of the material ο in the further capillary 101, namely both

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Materials on the same level. At a .... If the pressure increases, the flow velocity in the further capillary 101 is significantly higher than in the narrow » ren capillary 100, accordingly, according to Pig. 6, the material ο in the capillary 101 has moved significantly further than the material x, which up to the point of intersection the capillaries 100 and 101 has reached. During the subsequent pressure reduction, the material ο in the large capillary is moved back to its starting position while the material χ is conveyed partly into the further capillary 101 and partly into the narrower capillary 100 due to its local position. As a result, in the capillaries there is something that cannot be achieved with conventional methods effective mixing achieved, in which at the end of the oscillation perlode part of the material is accordingly mixing in the direction of flow on a lighter one Level is located. -

When the component has reached the immediate vicinity of the sorptior's place, the actual must finally Sorption step take place. On this sorption process the process according to the invention itself has no influence. However, this is irrelevant because the actual sorption runs very quickly. -

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In addition to the above-mentioned advantages in the area of the usual Hassenübergaqges, the invention has Process still the other important effect to which it is there is no counterpart in the conventional method, since it is eally guided through interfaces material inevitably passed through the boundary surface from the mixtures on both sides of a boundary surface and thus an oern of a component is achieved through the interface «neon at the interface there is resistance, i.e. the mixture is different on both sides of the interface. This applies both to interfaces between porous parts and the gas phase as well Interfaces within the porous particles too. The latter consist, for example, of interfaces between Sieve crystals and the binding agent carrying them and pseudo-interfaces in homogeneous solids between areas with different properties.

The Druckjoszäll ι generated in the inventive method tionea lifcmen lead to technical difficulties, since the System must be designed for the stresses generated by the oscillating pressure. It is therefore a lot » often useful to reduce the oscillation amplitude based on a given amplitude of the internal oscillation * This could be accomplished in a number of ways, but each time the system is modified to include a part of the material periodically accumulated in the bed on the

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porous solid is adsorbed instead of in the oasis phase too remain and contribute to the periodic pressure increase. If the system is built so that the partial Deriving the loading of the porous solid according to the partial pressure of a component present in the gas phase at the applied partial pressure a finite or possesses substantial (substantial) value «becomes the The amplitude of the pressure oscillations is reduced. If, to facilitate flow, a component is added to the gas phase which has a finite or substantial partial derivation of the load according to the partial pressure, the result is a reduction in the Pressure oscillation. The same effect can be achieved by adding a component to the porous solid the.

In the quantitative delimitation of the area of application of the method according to the invention, it is expedient to use physically measurable properties of the system as a basis.

Since the systems suitable for the method according to the invention have numerous properties that differ greatly in terms of dimension and order of magnitude *, for example the Degree of porosity, the pore size, the particle size and the The amount of material adsorbed in the porous particles, the working temperature and the working pressure, is characterized

009813/1360:;

V5421Q3

can they

are / limits of the method according to the invention are expediently explained by equations »which relationships between the properties of the system and the measurable Show oscillation

The method according to the invention is only applicable to systems which contain porous solids. The degree of porosity, expressed as the ratio of the seed surface for nitrogen to the outer surface of the particles «is supposed to be the correspond to the following equation:

wherein:

A ^, the total surface area available for adsorption in β ² , expressed as nitrogen adsorption area for an aero-molecular layer according to the BET method and

A _{8 is} the outer surface in β ² , expressed as the surface area of spheres With the volume of the average particles «calculated as the difference, divided by the number of particles, between the volume V of the zone containing the bed in sp * and the volume V _y between the porous particles in the zone existing hollow riuae in w? (bestlaat by filling up with a non-wetting liquid such as mercury in Ataosphttrendruok) represents ^ and

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15JW103

about 100, preferably about 500 and especially is about 50,000.

To carry out the method according to the invention, a periodic flow must be generated in the pores of the particles · To generate this flow will be periodic Material introduced into and withdrawn from the bed. The amplitude of this oscillation is defined as arithmetic Sum of the material accumulated in and withdrawn from the zone in a period, expressed as volume V · This is quantitatively defined in the following oil holes by the relative inflow and outflow velocities.

t + p

ac

German

German

.t + p) ^V i

German

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^V el ♦

(5) V ₁ - V ₁ , * V ₁₂

where t is the current time (in see), ρ the oscillation period (in see.) »

^V el ^the ^^ eatene outflow speed of gas and possibly liquid from the bed,

^V e2 is ^{the instantaneous} flow rate from the bed into the oscillating volume,

V _{11 is} the current inflow rate of gas and, if applicable, liquid into the bed,

V _{12 is} the instantaneous flow rate from the oscillating volume into the bed,

all flow values after correction of the Gas flow to the corresponding flow at the average pressure at the respective points (in 0.028 nrVsec) represents «

However, not all of the accumulated or «, material withdrawn from it is »pressed into or« led out of the pores of the particles. this applies especially for relatively narrow JPores, which offer strong resistance to the flow · For those only in moved the cavities between the porous particles

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Material quantities can be corrected by precisely taking into account the volume of the cavities, the total pressure and the amplitude of the pressure oscillation. The amplitude of the oscillation in the forums of the system, expressed as volume V _n , is quantitatively defined by the equation

t + p

(6) V_ - ^P T

pen

dt - V.

wherein

^v pen is the amplitude of the oscillation in the fora of the particles as the arithmetic sum of the volume of material introduced into the pores of the particles in a period and removed from them (in 0.028 v?) _t

P-, the total working pressure (in ata) and

P _{0 is} the pressure oscillation from minimum to maximum (in ata)

represent.

The inventive method depends on the movement of the material in the pores of the porous solid ensuing mixing. There is a minimum distance or minimum amplitude below for the movement which the procedure no longer has any significant effect. This minimum amplitude must be compared to the dimensions

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the pores and the distances between pore crossings can be considerable. This periodic description representing a segment for the material located in the pores close to the particle surface, the displacement amplitude can be calculated by dividing V is calculated by the outer surface area of the particles and correction for the porous part of the particles will. This minimum distance, based on the total pressure of the system, the amplitude of the pressure oscillation that Oscillation perlode, the relative currents in and out the bed, the volume of the voids and the outer surface of the particles is defined in the equation:

(7) k wherein:

V-V.

^V p ^A s

JL

V ₄ -

dt -

V is the pore volume of the porous particles in the zone! Measured by completely filling a degassed and dried bed with a completely penetrating liquid compound such as N ₂ or HgO and subtracting V _y from the volume measured for this liquid) and

vicinity

represents the oscillation spread in the pores / the surface, which is at least about 0.5yU, preferably at least about 10yu and in particular is at least about 0.3 mm.

There is also a maximum amplitude for the flow in the particles, the crossing of which is of no practical use

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brings. This maximum amplitude is used in the following Equation is expressed as a factor k multiplied by the pore volume V. (Equation 8 corresponds to equation however, instead of the outer surface, the pore volume is included in the equation):

(8) k,

pen

/ t + p

^V e- ^V i

dt - V.

where k expresses the flow as a factor times the pore volume and at most 50, preferably at most and in particular is at most 0.1.

£ s is often desired to match the amount of material with the Starting composition in the one flowing out of the bed To keep the product as small as possible. This is for example the removal of η-paraffins from a Hydrocarbon middle distillate for lowering the pour point and for catalytic! Systems where the equilibrium conversion is so complete that the product is immediately suitable for sale. When using the Process according to the invention, with large flow amplitudes, the problem can arise that feedstock flows off with the withdrawn product, since this occurs in the discharge phase of the Perlode feed product fed to the bed must exit with the withdrawn product if the volume exiting the pores is equal to or greater than the volume

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- ■■ 25

£ * v voids tni bed. To avoid this problem, the maximum amplitude of the periodic flow must be reduced to a fraction of the void _{volume in bed Y y} . The fraction of the void volume filled during oscillation corresponds to the equation:

(9)

en

/ t + p

dt - V.

where Ic represents the oscillation flow as a fraction of the Kohlrauavolumens V _y and is at most 0.2, preferably at most 0.05 and in particular at most 0.002.

When generating de? internal oscillation due to periodic changes in the relative flows into or out of the bed, there is _{a maximum frequency for any given amplitude V & c,} since the flow velocity in the pores of the porous particles cannot be greater than the flows entering or exiting the bed · For any given amplitude V_ "a minimum time is required to reach this volume at a given flow

speed to introduce into the system, even if nothing leaves the system. The one corresponding to this minimum time

Maximum frequency ff corresponds to the equation:

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dt r " t

where f is the Oezlllaton frequency (in see ")

t + P Γ V. dt

■ in> * 6 * * »ax

1st. The minimum frequency should be the equation

suffice «where kg is about 0.01, preferably about 0.05 1st.

In some cases it is necessary to "limit the amplitude of the pressure oscillation" in order not to have to design the system for strong pressure fluctuations. Further, in some systems, for example, fluidized beds in itself Druckechwankungen occur "may in some cases, by increasing the oscillation amplitude in the pores of the part" ohen (VL _0n) As a result, an improved mass Nuber gear are achieved, the pressure variations occurring in the system _c Both can be achieved by that the system by adding a component to the gas phase and / or

009813/1360 ^BAD ORl® _NAL

the porous phase changes, so that the new system at the applied partial pressure is a finite or substantial (substantial) partial derivation of the loading of the material after printing. This is the case when the partial derivative of the equation:

(12) / I

OW

P _T K.

t + p

dt - V.

is enough in what

V is the amount of component c adsorbed in the bed, expressed as the corresponding volume of gas at pressure P ^,

P _{Q is} the partial pressure of component c (in 0.07 ata) y _{c is} the mole fraction of component c in the gas and

P _{ow is} the oscillation P _{Q of} the gas pressure at the same oscillation amplitude V measured in the absence of component c

represent.

For the same purpose one can also use the particles of the porous Solid add another porous solid, which a finite or considerable (substantial) partial derivation of the load according to the partial pressure for comprises one of the constituents of the starting material.

The invention is illustrated in more detail by the following examples.

BATH ORIGINAL 009813/1360

15A2103

example I.

In a series of experiments, a process for the separation of n-paraffin was carried out with and without oscillation in the adsorption stage. In both cases an old one clay binder su particles with a diameter of 1.6 na extruded 5A molecular sieve adsorbent used, pressure on the previously at Adsorptlonstenperatur and "with NE laden" bed was at a temperature of 385 ⁰ C and a absolute pressure of 250 na Hg a mixture of a previously extracted, hydrofined and dewaxed solvent (solvent 100 neutral) to a pour point of -6.7 ° C and 7 moles of NH per mole of hydrocarbon, at a rate of 0.3 kg of hydrocarbon per kg bedeaterial and hour.

In the test without oscillation, the feed and discharge rates were constant. In the practice of the invention, the discharge rate was measured by means of a device placed in the outlet of the bed at a frequency of 5.5 Perloden oscillating narrowing between zero and twice the mean drain speed per second controlled. The flow rate according to Pig. 8 equal to its maximum value in each period increased and then decreased to zero at the same steady rate. The feed rate remained constant in this case. The amplitude Jder

Oscillation was about 0.0014 at. BADORiQiNAL

009813/1360 j

Fig. 9 shows that the application of the invention internal oscillation compared to the attempts without oscillation to a lower pour point of the outflow Product and accordingly leads to a more complete removal of the η-paraffins.

In both cases, the n-paraffins were desorbed NH, passed over the bed. From the first 80 £ the desorbed hydrocarbons, the aromatics were removed and the aromatic-free desorbed hydrocarbons were analyzed by mass spectrometry. The results these analyzes are shown in Table 1.

Tabel

Removes paraffin

¹¹⁰ SUN nc ₂₁

^nC 25 ^ 26 ^nC 27

^nC 2ö ^nC 2Q

Removal of n-paraffins without oscillation
* * - with oscillation
* 0.7 0.7 2.0 2.3 5.9 5 * 2 7.5 9.5 8.7 13 * 1 6.9 12.2 3.7 8.1 1 * 7 5 * 9 0.7 1.9 0.2 0.8 0.4 0.1
0.2
0.2
0.1

Total n-paraffins 58.7 35 * 8

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The above data show that when the oscillation is used, a more efficient utilization of the adsorbent is achieved, corresponding to a higher loading of the adsorbent. In addition, according to the invention, η-paraffins with a higher molecular weight up to approximately Cj ₀ , but only n-paraffins up to C ₂ C without oscillation, were removed from the feedstock.

The main advantages of the process according to the invention in the adsorption of η-paraffins on molecular sieves are:

(1) a more complete removal of the η-paraffins from the Input product,

(2) a higher loading of the adsorbent and

(3) removal of higher molecular weight n-paraffins.

Example 2

In a further series of experiments, the removal of η-paraffins with and without oscillation in the desorption stage was investigated. An adsorbent according to Example 1 was initially loaded with η-paraffins without oscillation, adding a mixture of a distillate with carbon numbers from 15 to 33 and 5 moles of NH per mole of hydrocarbon, at a total pressure of 100 mn Hg absolute and a temperature of 385 ° C at a rate of 0.4 kg Hydrocarbon per kg bed material and piece 40 minutes Was passed over the bed.

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In both cases, NH was used for desorption, at a temperature

O temperature of 585 C and a pressure of 2.1 ata with a Speed of 0.89 kJ / hour passed through the bed. The test without oscillation was carried out with a substantially constant restriction in the bed outlet. In the test with internal oscillation, the outlet orifice oscillated between fully closed and fully closed fully open position, with a frequency of 0.5 periods per second. As a result, the outflow velocity was varied in the manner shown in FIG Periodic pressure fluctuations of - 0.035 at observed in the bed

As can be seen from Fig. 11, the n-paraffins were at Using the internal oscillation removes you from the bed much faster. After the introduction of 1 kg of feed per kg of bed material, there were only no oscillation 775 * of the n-paraffin removes compared to 95 # when used the oscillation technique according to the invention. This shows the more effective use of the displacement medium NH, when using the internal oscillation

The method according to the invention can be used accordingly can also be used for other sorption processes in a modified manner with considerable technical advantages.

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Even with catalytic! Procedure, especially with a catalyst applied to a porous support material and a gaseous feed product, optionally containing liquid constituents, are used the oscillation technique according to the invention has significant technical advantages, in particular a faster conversion a better utilization of the catalyst and a suppression of side reactions achieved.

hb / St: en / mU

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Claims (1)

(Cf. Sun 563.258 - prio April 28, 1964 5417) Esso Research and
Engineering Company Elizabeth. H.J »/ V.St.A. Hamburg, April 22, 1965 Claims I <= method for improving the mass transfer of porous substances "in which a gas phase is passed over a porous material" characterized in that periodically changing currents are generated by oscillation of the gas pressure in the pores of the porous material. 2. The method according to claim 1, characterized in that a gas phase consisting of at least two components over a porous material with a pore size of j> to 10, preferably 5 to 10 Pi conducts, which for at least one of the constituents has an adsorption capacity and / or a catalytic effectiveness. 3. The method according to claim 1 and 2, characterized «that an oscillation of the gas pressure with a frequency of 0.01 to 50,000, preferably 0.01 to 5 * 000 pearls per second and an amplitude of 0.000007 to Ik _{9 is} preferably Applies 0.0007 to 0.14 atmospheres, 009813/1360 Method according to claim 1 to 5, characterized that one charged the oscillation of the gas pressure by changing the in the with porous material Zone a «and / or outflowing gas generated. 5. The method according to claim 1 to 4, characterized in that that the oscillation is based on an alternating movement of the gas in the pores of at least about 0.5 / U and a correspond at most to the 5Ofaeheri pore volume V o.es Sets volume V of the gas flow penetrating into the pores. Method according to Claims 1 to 5, characterized in that a porous material is used whose inner surface A _{n is} at least 100 times, preferably at least 500 times, the outer surface A, 7. The method according to claim 1 to 6, characterized that the gas phase and / or the porous material at least; contains a liquid component / 8 * Method according to claim 2 to 7 _t characterized in that to achieve an alternating in the pores by at least about O »5yU and one 009813/1360 _{the volume V pen} of the gas flowing in and out of the pores corresponding to at most 50 times the pore volume V the frequency f of the oscillation between 0.01 and! times the maximum frequency? ? _ΜΧ regulates «where: f Max t + p ^V e- ^V i German v _e dt German el i2 is and t the current time in seconds » ρ is the period of oscillation in seconds » V- the current flow rate of gas and possibly liquid from the bed » ^V e2 ^{the nonlentane} flow from the bed into the oscillating volume » Vj ₁ the current feed rate to the and optionally liquid in the bed and 009813/1360 V ^ ₂ the r., ;; i! .Entijiio flow from dew ο32ϋ \ Λϋϊ · ι; η; Volume in the bed, all flow values still correction dt ν gas flow to the corresponding flow at the average pressure at the respective point tu (in 0.028
represent" The method according to claim 8, characterized in that the volume V of the gas entering and exiting the pores is at most 5% of that in the bed outside the c ρ << · ^; ; sen particles lying volume V _v limited. 10 "Method according to claim 1 to 9, characterized in that that a component c is added to the gas phase and / or the porous material, for which: 0.1 OW ow t + p dt - V where: P _{n is} the partial pressure of component c (in 0.07 ΛI ■ y is the molar fraction of component c in the gas, V is the amount of component c adsorbed on the bed material, expressed as the volume of gas at pressure Pm, P _{0 is} the pressure difference between the maximum and occurring during the oscillation 009813/136 0 BAD ORfQfNAL minimum gas pressures (in 0.07 at) V is the volume amplitude of the oscillation in the bed, ex presses ice of the v. during a cycle of the bed ziiß • j. te and volume subtracted from it (in 0.028 tor), P is the pressure difference measured in the absence of component c at _{the same pressure difference P Q} and the same voluncr.iplitudc V "_; and t, p, V, V. and V correspond to the definitions in cen / meprüchen 8 and 9 .. Method according to claims 1 to 10, characterized in that that an Ecolithic molecular sieve is used and separates at least one component of the gas. Method according to claim 11, characterized in that r.an uses a Zoollthian molecular sieve with a pore size of about 5 "and with an oscillation with a frequency of 1.5 to 10 periods per second and an amplitude of 0.00035 to 0.14 separating at η-paraffins from paraffin-containing gases. 00 98 13/1360 Read more