JPH01221334A - Isomerization method and apparatus - Google Patents

Abstract

Processing and apparatus are provided for upgrading the octane of a mixed hydrocarbon gasoline feedstock by an integrated adsorption-isomerization process which catalytically isomerizes normal paraffinic hydrocarbons and concentrates non-normals in a product stream, in both the reactor-lead and absorber-lead configuration. The process includes passing an absorber feed stream comprising hydrogen as well as hydrocarbons to an absorbent bed to absorb normal hydrocarbons. The hydrogen is preferably obtained from a hot hydrogen-containing process stream which is not cooled or separated into component parts prior to forming the absorber feed. In some embodiments, the hot-hydrogen containing stream comes from reactor effluent and in others from desorption effluent. According to the invention, the only hydrogen which will require cooling and separation from a hydrocarbon component is that which is recycled for desorption. The invention provides improved energy efficiency and can reduce equipment size and complexity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the production of octane mixed hydrocarbon gasoline feedstocks by a complete adsorption-isomerization process that catalytically isomerizes normal paraffinic hydrocarbons and concentrates non-normal components in the product stream. This invention relates to improvements in methods and devices for sophistication.

As a technique for increasing the octane ratio of certain hydrocarbon fractions, particularly normal and mixed feedstocks containing isopentane and hexane, isomerization typically occurs in the feed stream before and after an adsorption-desorption cycle to isolate the non-normal fraction. Those containing hydrocarbons are known.

In one widely used method, all feedstocks are first subjected to a catalytic reaction and then subjected to a four-membrane separation step using a molecular sieve adsorption device operated under essentially isobaric and isothermal conditions. It will be done. Prior to this four-stage step, the reactor effluent is separated into an adsorber feed stream and a hydrogen-rich gas stream. The adsorber feed stream is passed through the adsorber in two adsorption stages. The first is to displace the void space gas from the pre-desorption step, and the second is to produce an adsorber stream that is highly reduced in adsorbed (e.g. normal) hydrocarbon content.

The adsorber is then desorbed in two stages with a hydrogen-rich gas stream. The first is the transfer of void space gas from the adsorption stage described above, and the second is the removal of adsorbed hydrocarbons from the adsorbent. This is known as the reactor lead process.

According to another known method, the feed is first passed through an adsorption device, which immediately removes non-normal fractions again during a four-stage adsorption process. The normal fraction from the second desorption stage is then mixed with sufficient hydrogen to protect the isomerization reactor, and then substantially removed from the newly formed non-normal fraction and the normal fraction is removed from the reactor. isomerized with recycling. This is known in the industry as the suction bag W guiding process.

By operating a four-stage adsorption cycle in the prior art process, substantially all of the hydrogen or other purge gas is removed from the adsorbate prior to adsorption, and the adsorption effluent has a molecular weight of about 101 b/? ,b to approximately 701b/lb at the end of the phase. Since the heat exchange system must be adapted to operate at a minimum heat content (ie, lowest molecular weight), it has been necessary to oversize the heat exchanger and waste heat from the high heat content portion. It is desirable to produce adsorbent effluents that exhibit less variation in molecular weight.

The operation of adsorption equipment is essentially a batch process.

To obtain a continuous flow of adsorber effluent with a four-stage adsorber cycle, the prior art typically employed four adsorber units operated in time relationship. It is desirable to reduce the capital cost of adsorption equipment and associated conduits, valves and controls.

An increase in the operating pressure of the adsorption device increases the normal partial pressure,
While thereby improving its adsorption, increasing the pressure of adsorption devices in the prior art does not result in the expected increase in adsorption efficiency. The adsorption device is filled with solid 8V-Raseeb adsorbent and has significant void space volume not occupied by solid material. As in the prior art, however, operating the adsorber at increased pressure has the disadvantage of increasing void space accumulation of gas during the process. It would be advantageous to achieve a better ratio of adsorption normal to void space accumulation of hydrocarbons.

It is further desirable to reduce the total adsorption bed volume and improve the energy efficiency in an integrated isomerization-adsorption process that can complete the total isomerization of all normal hydrocarbons. Most preferred is to increase the degree of concentration of reactor and adsorber operations for energy savings and to reduce the amount of molecular sieve feedstock and vessel capacity required.

This technology yields a number of integrated isomerization-adsorption systems to isomerize feed streams containing normal and non-normal hydrocarbons and produce a product stream useful as a feedstock for gasoline blending. did.

Most prior art systems integrally isomerize the normals in the feed, which is known in the industry as a total isomerization process (total isomerization process).
cesses) or TIP. Among these,
In the reactor lead system, fresh feed and any recycle is fed to the isomerization reactor prior to non-normal separation, and in the adsorber lead system, fresh feed is fed to the adsorber prior to isomerization. As currently practiced, both of these systems typically have three or four adsorption beds, which are cycled through at least one adsorption stage and two desorption stages.

In Canadian patent specification 8111,064,056,
Level et al. describe an integrated isomerization process in which large fluctuations in the concentration of both n-pentane or n-hexane in the reactor feed can be prevented by proper control of the operation of the Mihara adsorption system. ing. According to that disclosure, only three beds are adsorbed at any one time, and the final stage of adsorption in - of the three beds is simultaneous with the first stage of adsorption in the other of the three beds.

Both adsorber-driven and reactor steps are specifically illustrated. The adsorber lead step requires initial separated hydrogen from the reactor effluent. The fresh feed is then combined with the reactor hydrocarbon effluent and the combined stream is passed through an adsorption unit to remove non-normal hydrocarbons such that the feed to the reactor is dominated by normal hydrocarbons. Become something. This deals with streams with widely varying molecular weights and the large energy input of cooling the entire reactor effluent to separate the hydrocarbon and hydrogen portions, and then reheating both. The zero reactor lead process, which requires heat exchange equipment suitably sized, is analogous in this regard.

In U.S. Pat. The integrated isomerization process is described.

However, this reactor lead step requires cooling of the entire reactor effluent in order to separate the hydrogen from the hydrocarbon portion prior to the separation of normal from non-normal in the four-stage adsorption of sexidine. The effluent from the isomerization reactor is concentrated to separate the hydrocarbon fraction. This fraction is then reheated as a vapor-state feed at superatmospheric pressure into at least four fixed beds of a system containing a zeolite-based molecular sieve adsorbent having an effective bore diameter of substantially 5 mm. Each is passed through the fixed bed in periodic succession, and the following process steps are carried out periodically in the fixed bed.

A-1 Adsorption-filling, the vapor in the bed void space primarily contains non-adsorbable purge gas, and the incoming feed absorbs the non-adsorbable purge gas from the bed void space from the non-adsorbable feedstock at that location. shut out without substantial internal mixing with the fraction; A-2 adsorption, the feedstock passes through the bed simultaneously and the normal components of the feedstock are selectively transferred into the internal cavities of the crystalline zeolitic adsorbent. The unadsorbed components of the feedstock are usually removed from the bed as an effluent with significantly reduced feedstock component content; and 97% normal adsorbent, the bed void space containing a mixture of normal and non-normal fractions in proportion to the feedstock, which absorbs the non-adsorbable purge gas. Preferably, the normal adsorbed feedstock content in the bed effluent is 40% in an amount sufficient to remove the void space feedstock vapor, but not more than to produce about 50 mole percent.
No more than 0 mole percent is purged countercurrently with respect to the direction of A-2 adsorption by passing the bed through the bed.

D-2 purge desorption, the non-adsorbable purge gas is removed countercurrently to the A-2 adsorption until the main part of the adsorbed and normal components is desorbed and the bed void space vapor mainly contains the non-adsorbable purge gas. By passing through the bed, the adsorbed feed normal is selectively desorbed as part of the desorption effluent.

This process, which results in wide variations in the molecular weight of the adsorption effluent, has considerable complexity and requires that all of the recycled hydrocarbons and hydrogen be cooled and reheated.

There is currently a need for improvements in isomerization-adsorption systems that would result in reduced energy consumption, as well as favorable adsorption bed volumes and overall adsorption section complexity.

Contrary to conventional technology, the present invention provides an integrated isomerization and adsorption process for the upgrading of light naphtha feeds by changing the equipment. It is based on the discovery that significant improvements can be made in terms of reduced adsorption sector 3+IM properties, and improved energy efficiency. The present invention provides an improved apparatus for increasing the non-normal content of feed streams containing normal and non-normal hydrocarbons through a new integration of isomerization and adsorption techniques in both adsorber-directed and reactor-directed methods. and a method.

The process upgrades a hydrocarbon feed containing non-normal hydrocarbons and normal pentane and hexane to obtain a hydrocarbon stream enriched in non-normal fractions, and comprises an adsorption section comprising an adsorption bed. passing an adsorber feed stream containing hydrogen and hydrocarbons to adsorb normal hydrocarbons from the stream and discharging non-normal hydrocarbons and hydrogen from the adsorption section as an adsorption effluent; hydrogen-containing purge gas being adsorbed; a desorption effluent containing hydrogen and normal hydrocarbons; and at least a portion of the desorption effluent is subjected to an isomerization reaction. The method includes producing a reactor effluent containing a reactor hydrocarbon component containing hydrogen and a high ratio of non-normal hydrocarbons to normal hydrocarbons through a device.

When operated in reactor-first mode, the adsorber feed stream includes the reactor effluent, preferably prior to any significant cooling or component separation. This supplies hydrogen to the adsorption bed and maintains the heating value of the hydrogen and hydrocarbon components. Moreover, this embodiment of the process allows recycling of a large portion of the hydrocarbons by weight in a given cycle without cooling to any effective degree.

Preferably, only hydrogen that requires cooling and separation from the hydrocarbon components is desorbed by recycling. The desorption effluent in this example is:
Preferably it contains hot hydrogen and hydrocarbons and is not cooled or fractionated prior to recycling for isomerization of normal hydrocarbons. This embodiment can be efficiently accomplished by placing the isomerization catalyst and the molecular sieve adsorbent in the same tank.

When operating in adsorber-first mode, the adsorber feed stream contains fresh hydrocarbon feed and recycle containing hydrogen and hydrocarbons from the reactor. Preferably, recycling from the reactor is reactor effluent that is removed directly without significant cooling or component separation. This thermal recycling supplies hydrogen to the adsorption bed and maintains the heating value of the hydrogen and hydrocarbon components.

The apparatus of the present invention provides a means to accomplish the method described above.

■Dish ■■Dish The present invention will be better understood, and its advantages will become more apparent, if the following detailed description is read in conjunction with the accompanying drawings. The drawings are as follows.

FIG. 1 is a schematic diagram of the reactor lead process and equipment arrangement, in which two pairs of reactor and adsorption equipment sections are used;
Each reactor/adsorber pair is contained within a single vessel.

FIG. 2 is a simplified schematic of various embodiments of FIG. 1, using manifold valves to maintain flow in the same direction throughout the cycle.

FIG. 3 is another embodiment of the reactor leading process and apparatus of the present invention, which employs a single reactor.

FIG. 4 is a schematic diagram of an adsorption unit lead-in step and equipment arrangement according to the present invention in which a portion of the isomerization reactor effluent is combined with hydrocarbons from the fresh feed and recycle to form the adsorption unit feed. ing.

The fresh feed contains normal and non-normal hydrocarbons. The feed mainly contains 5 to 6 carbon atoms.
It consists of various isomeric forms of saturated hydrocarbons. The expression "various isomeric forms" refers to all branched and cyclic forms of the indicated compounds, as well as straight chain forms. Also, the prefix designations "iso" and "i" are designations for all branched and cyclic (i.e., non-linear) forms of the indicated compounds.

The following compositions are representative of suitable feedstocks for processing according to the present invention: C4 and below 0-7i-Cs
10-40 n-C25-30 i-C, 10-40 n-C, 5-30 C2 and higher 0-1° Suitable feedstocks are typically obtained by refinery distillation operations, with small amounts of C1 carbonization Although it can contain hydrogen and even higher hydrocarbons, typically only trace amounts of these are present in total. Advantageously, the olefinic hydrocarbon is present in the feed in an amount of about 4 mole percent or less. Aromatic molecules and cycloparaffin molecules have relatively high octane numbers. Preferred feedstocks are therefore high in aromatic and cycloparaffinic hydrocarbons, e.g. containing at least 5 mol%, more typically 10-25 mol% of these combined components. .

Acyclic CS and C1 hydrocarbons typically constitute at least 60 mol% of the feedstock, more typically less (75 mol% together, and at least 25 mol% of the feedstock).
%, preferably at least 35 mol% isopencune,
A hydrocarbon selected from the group consisting of isohexane and mixtures thereof.

The isomerization reactor sections (21 and 27 in FIG. 1) contain an isomerization catalyst that selectively and substantially undergoes isomerization under the operating conditions of the process of the invention. It can be any of a variety of active molecular sieve-based catalyst compositions known in the art. - The above-mentioned catalysts in the boat fishing category have an apparent pore diameter large enough to adsorb neopentane, 5i02/
Al zch molar ratio and an alkali metal cation of 60 equivalent% or less, preferably 15 equivalent% or less, and is not associated with any metal cation or associated with divalent or other polyvalent metal cations. To those that are not associated with alkali metal cations that are either! 04-crystalline zeolite molecular sieve with tetrahedra.

Since the feedstock contains some olefins and is subject to at least some cracking, the zeolite catalyst component is preferably combined with a hydrogenation catalyst component, preferably a noble metal from Group I of the Periodic Table of the Elements. The catalyst component can be used alone or in combination with a porous inorganic oxide diluent material as a binder. The hydrogenating agent can be supported on the zeolite component and/or on the binder. A wide variety of inorganic oxide diluent materials are known in the art, some of which exhibit hydrogenation activity themselves. Thus, the term "inorganic diluent with a hydrogenating agent" includes both those carrying a separate hydrogenating agent that itself has hydrogenation activity, and those that are themselves hydrogenation catalysts. It is understood to mean. Suitable oxides as diluents which themselves exhibit hydrogenation activity are the oxides of metals of Group I of the Mendeleev periodic table of elements. Representative examples of such metals are chromium, molybdenum and tungsten.

Preferably, the diluent material has no apparent catalytic cracking activity. The diluent should not exhibit a greater quantitative degree of cranking activity than the zeolite component of the overall isomerization catalyst composition.

Suitable oxides of this latter category include alumina, silica, oxides of metals of groups II, II-A and rV-B of the Mendeleev periodic table, as well as silica and groups II, II-A and IV-B.
Cogels with oxides of Group B metals, especially alumina, zirconia, titanium amitria, and combinations thereof. Aluminosilicate clays such as kaolin, acpargite, seviolite, polygarskite, bentonite, montmorillonite, etc. are also suitable diluent materials when made into a flexible plastic-like state by thorough mixing with water. Yes, especially if the clay has not been pickled to remove substantial amounts of alumina.

A suitable catalyst for the isomerization reaction is disclosed in U.S. Pat.
, 761 and 3,236.762. A particularly preferred catalyst is about 510 g/A E
Zeolite) Y with a molar ratio of 203 (U.S. Pat. No. 3)
．． 130.007), the sodium cation content was reduced to about 15% by weight by ammonium cation exchange, and then between about 35% and 50% by weight of rare earth metal cations were introduced by ion exchange. , followed by calcination of the zeolite to effect substantial deamination.

Platinum or palladium as hydrogenation component in an amount of about 0.1 to 1.0% by weight can be placed on the zeolite by any conventional method. The disclosures of the US patents cited above are incorporated herein by reference.

The zeolite-type molecular sieve used in the adsorption bed must be capable of selectively adsorbing the normal paraffins of the feedstock using standard molecular size and configuration. Therefore, such molecular sieves should have an apparent pore diameter of less than 6 angstroms and greater than about 4 angstroms. A particularly suitable zeolite of this type is U.S. Pat.
3.243, which zeolite A has an apparent pore diameter of about 5 angstroms in some of its divalently exchanged forms, particularly in the form of calcium cations, and It has a very large ability to adsorb paraffin. Other suitable molecular sieves include Zeolite R (U.S. Pat. No. 3,030,181), Zeolite T
(U.S. Pat. No. 2,950,952), as well as the naturally occurring zeolite-type molecular sieves chabazite and erylonite. These US patent specifications are hereby incorporated by reference in their entirety.

As used herein, the term "apparent pore diameter" refers to the maximum critical dimension.
tion) or as a molecular species that is adsorbed by an adsorbent under normal conditions. The critical dimension is defined as the diameter of the smallest cylinder that will accommodate a molecular model constructed using effective values of bond lengths, bond angles, and van der Waals radii. The apparent pore diameter is always the structural pore diameter (
structural pore diameter)
, which can be defined as the free diameter of the appropriate silicate ring in the structure of the adsorbent.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described primarily in accordance with preferred embodiments. In this embodiment, a mixed hydrocarbon feedstock (fresh feed) is upgraded for use as a gasoline blendstock by an integrated combination of adsorption and isomerization.

The invention will first be described in conjunction with FIG. 1 in terms of a reactor leading arrangement. The arrangement is such that an adsorber bed and a reactor bed can be present in the same vessel as a virtual total integration of isomerization technology and adsorption technology. This arrangement combines the advantages of reactor-directed and adsorber-directed systems. The normal forms in the feed can be partially isomerized before adsorption, as in a reactor-driven system;
This makes the adsorption compartment smaller. For desorption, the advantages of adsorption device leading are evaluated. Substantially normal bodies are desorbed and fed to the reactor section, so that the catalyst capacity is utilized more efficiently.

In FIG. 1, fresh feed in line IO is combined in line 12 with hydrocarbon recycle from line 14. This combined hydrocarbon stream is transferred to heat exchanger 1
At 8, it is heated by indirect heat exchange with the adsorption effluent carried by line 16.

From the heat exchanger the hydrocarbon stream is passed to the furnace 20 where it is sufficiently heated to form the isomerization reactor section 2 of the vessel 23.
1 (catalyst bed) and then to adsorption section 22 (adsorbent bed). It is of course possible to have the catalyst bed and adsorbent bed in different vessels if desired.

The reactor feed streams in line 24 include a stream of hot hydrocarbons from furnace 20 and a hot reactor effluent (i.e., hot recycle or hot hydrogen recycle) from line 26 containing hydrogen and hydrocarbon components. It is formed by combining the circulating materials). Appropriate control valves and controls (not shown) direct feed flow 24 to the appropriate one of vessels 23 and 29. These containers alternate between the two functions shown in FIG. 1 as being performed by each of the containers.

Depending on the particular catalyst composition used, the operating temperature within vessels 23 and 29 will generally be in the range of 100 DEG to 390 DEG C., and the pressure will be in the range of 175 to 600 psia.

Desirably the temperature is within the range of 220° to 280°C and the pressure is between 200 and 400 psia, preferably between 200 and 300 psia, and most preferably about 250 psia.
It is psia. Catalyst bed i is maintained under hydrogen partial pressure sufficient to prevent coking of the isomerization catalyst under the conditions maintained in the reactor. Typically the hydrogen partial pressure is 100
~250 psia, preferably 130-190 psi
a and the hydrogen is kept in the gaseous state 1 of the reactor contents
It constitutes 0-90 mol%, preferably 35-75 mol%, most preferably 45-65 mol%.

The feed to the reactor includes hydrogen and hydrocarbon reactants such as normal pentane, normal hexa, isopentane, isohexane, as well as some of the light hydrocarbons produced during the reaction and possibly as part of the feed and make-up. Contains the amount. Since they are non-sorbing, they are held in the process at an equilibrium level and circulated with the recycle stream.

Preferably the adsorbent in adsorbent beds 22 and 28 has an effective pore diameter of substantially 5 Angstroms. The term bed voi space for the purposes of this description
d 5 pace)' means any space within the bed that is not occupied by solid material, except for the intracrystalline cavities of the zeolite catalyst. The pores within any binder material that can be used to form aggregates of zeolite crystals are believed to be bed void spaces. The two adsorbent beds shown in the scheme of Figure 1 each cyclically carry out two stages: ADS: deliberate mixing of the feed with hydrogen before introducing it to the feed end of the adsorption device; It is then adsorbed and the product and hydrogen are withdrawn from the outlet end of the adsorption device. Levels typically constitute between 1O and 90 mol% of the adsorber feed, preferably between 35 and 65 mol%, and most preferably between 45 and 55 mol%. Due to the presence of hydrogen in the feed as well as in the product, there is relatively little variation in the molecular weight of the product;
Therefore, even more effective heat exchange is performed. (A
There is no t process. ) DBS: using hydrogen to desorb the bed in a countercurrent direction with the feed and then sending the entire effluent as feed to the isomerization reactor without internal recirculation. (No D1 step.) The presence of hydrogen in the adsorber feed improves heat exchange. Heat exchangers work better in steady state systems than in dynamic systems such as conventional TIPs.

The heat content of a process stream, such as an adsorption effluent, is a function of the molecular weight of the stream. The heat content varies in standard conventional TIP processes from about 10 pounds/pound mole at the beginning of the process to about 70 pounds/pound mole at the end of the process. Since the heat exchange system must be designed to operate at a minimum heat content level, a significant amount of high heat content fraction cannot be utilized effectively. In the present invention, the molecules of the adsorbed effluent are approximately 10 to 40
Varies over pounds/pound moles.

In steady state mode there is no variation in molecular weight.

Therefore, the steady-state approach
h) The mathematical relationship showing
1ar iveight) Deviation from AMW = (Maximum Molecular Weight - AMW) For standard conventional TIPs, %SS is calculated as follows: %SS = (40-(70-40))/40 =
25% Similarly, for the present invention, %SS is: %SS=
(g5-(40-25))/25=40%.

The value of 40% for the inventive system is significantly closer to the theoretical steady state value of 100% than the standard practice value of 25%.

The present invention also provides better adsorption device and reactor integration which provides further advantages.

Although it is clear that the number of adsorption devices in the present invention is advantageously reduced from four to two, it is not clear why the adsorbent inventory is lower and why the integration of the adsorption device and the reactor is It is unclear whether this is necessarily better taking into account the increased flow to the catalyst compartment.

Adsorbent residual levels for the present invention are lower than for equivalent standard conventional TIP systems. This is because less normal paraffin is processed through the adsorption device. In the conventional TIP method, the DI process (initial part of desorption)
performs two functions: one is to prevent the hydrogen-depleted desorption effluent from contacting the catalyst, and the other is to return the Di effluent to the adsorption unit for re-adsorption. be.

The effect of this is to maximize the size of the adsorption device and minimize the size of the reactor. In the present invention, D.I.
A portion of the desorption effluent is passed directly to the isomerization reactor,
A portion of the desorption effluent is then further isomerized and then recycled back to the adsorption device. Therefore, the effluent is further isomerized before being recycled to the adsorption device, so that less normal is ultimately recycled, resulting in lower adsorbent residuals.

In the present invention, the adsorber capacity is expected to be slightly lower because of the presence of hydrogen in the adsorber effluent and because adsorber capacity is a function of the partial pressure of normal bodies in the feed ( The effect is small because at normal body partial pressures in both cases, above 50 psia, the adsorbent loading is about 90% of full capacity).

However, this can be compensated by operating the adsorption device at high pressure to increase the normal body partial pressure. In fact, high pressure operation, while advantageous in the present invention, cannot be conveniently utilized in conventional TIP systems. In conventional TIP systems, an increase in operating pressure results in only a minimal increase in adsorption capacity, but substantially increases the undesirable void space capacity (v
oid 5pace storage).

This is because the carrying capacity is directly proportional to the total pressure. Furthermore, an increase in operating pressure requires a corresponding increase in operating temperature to prevent condensation. Increased operating pressure is desirable in the present invention. However, since hydrogen is present, the increase in pressure increases the void storage capacity.
) has no significant harmful effect on Additionally, for hydrogen-containing feeds, the condensation temperature is so low that no corresponding temperature increase is necessary.

Catalyst volume in conventional TIP systems is calculated as a function of the average feed flow rate in weight units.

The initial part of the desorption effluent, the Di effluent, is recycled to the adsorption device before being fed to the reactor, so that the conventional TIP
The average flow rate for the system is lower than for the present invention. It is expected that the required catalyst volume should be relatively high for the present invention.

However, in the present invention, smaller catalyst volumes than would be expected can be effectively used due to the high isomer content of the initial portion of the desorption effluent.

That is, some portion of the initial effluent can be passed through at a higher than normal feed rate since it is already partially isomerized. The remainder of the desorption effluent, which is low in isomer content, can be passed through the reactor at more typical feed rates. The net result is that even though the reactor effluent rate is significantly higher in the present invention, the present invention utilizes the high isomer/high flow rate portion of the desorption effluent much more effectively than in conventional TIP. This means that the increase in catalyst volume is not proportional.

The following description details the operation in which adsorption takes place in bed 22 and desorption takes place in bed 28. The reactor feed from line 24 is directed via suitable lines, manifolds and valves (not shown) to vessel 23 where it is isomerized in catalyst bed 21 and is then fed to the reactor effluent enriched in non-normals. The effluent is passed through an adsorbent bed 22 where adsorption takes place. Each of the adsorption beds in the system, beds 22 and 28, contains molecular sieves in a suitable form, such as cylindrical pellets.

As the reactor effluent from catalyst bed 21 begins to enter adsorbent bed 22, bed 22 contains residual purge gas from the previous desorption step. Preferably, the purge gas contains hydrogen due to the need to maintain at least a minimum hydrogen partial pressure in the isomerization reactor. This purge gas is passed through line 50 as a recirculation stream of purge gas during desorption.
is fed to the adsorbent bed via The feed through line 24 first scrubs bed 22 vigorously to remove any remaining hydrogen-containing purge gas. This does not end the stage, but the reactor effluent from bed 21 continues to flow as adsorbent feed to adsorbent bed 22 and the product of the adsorption effluent is withdrawn via line 16.

As adsorption continues, the normal paraffins in the feed are adsorbed by bed 22 and the adsorbed effluent, hydrogen and unadsorbed non-normal bodies, is removed from bed 22 through a suitable valve and manifold arrangement (not shown). Appear. The adsorption effluent is transferred to line 16, heat exchanger 18, air cooler 32 and heat exchanger 34.
It is then separated in separator 36 into a hydrogen-containing overhead product for recycling and an isomerization product.

The overhead gas is recovered by separator 36 and then combined with the similar overhead product from separator 40. Separator 40 separates the reactor effluent takeoff from reaction bed 27 in line 42 with the overhead product removed by line 44 and the overhead product removed via line 14 as described above. The reactor hydrocarbon product is separated from the output reactor hydrocarbon product.

The combined flow formed from lines 38 and 44 is fed via line 46 to a recirculating compressor 48 and then to line 50.
is returned to the vessel containing the adsorbent bed for adsorption. In this case, appropriate valves direct the flow to a heat exchanger 52 and a heater 54 before entering a vessel 29 containing a desorption bed 28.

Effluent from bed 28 passes directly to reactor bed 27.

During the desorption stage, first purge the void space adsorber feed;
Next, the selectively adsorbed normal paraffin is desorbed from the zeolite molecular sheep. The desorption effluent from bed 28 contains hydrogen and hydrocarbons throughout the stage. The desorption effluent passes directly to the isomerization reactor bed 27 as reactor feed.

The description so far is for one stage in a total of two stage cycles for the system.

For the next step, operate the appropriate valves to
A vessel 29 having a bed 7 and an adsorbent bed 28 receives the feed to the reactor bed which passes the reactor effluent to the adsorbent bed 28 for adsorption and then the bed in vessel 23. 22 initiates desorption, allowing the desorption effluent to pass directly to catalyst bed 21. At the end of the two stages both adsorbent beds accomplish the adsorption and desorption stages.

The isomerization operation results in some hydrogen loss from the purge gas due to hydrogenation of the starting material and cracked residue. Hydrogen is also lost due to solubility in the product and possibly to exhaust from line 50 (not shown), although the latter can be controlled by appropriate pulping means. These losses require the addition of make-up hydrogen. Make-up hydrogen can be supplied in impure form, for example via line 62, typically as an off-gas from catalytic reforming or steam reforming of methane. These hydrogen sources are typically reasonably pure for isomerization operations that involve venting from a recycle stream.

Refinery streams with lower purity are also sufficient. The desorption effluent in line 58 is, for example, n-pentane and n-pentane.
- Contains desorbed normal hydrocarbons such as hexane, hydrogen, light hydrocarbons, and other impurities including the purge gas used for desorption. This effluent is the reactor feed and is passed to isomerization reactor 60.

A portion (up to 100%) of the reactor effluent from bed 27 is transferred to vessel 23, first to reactor bed 21 and then to adsorbent bed 22.
It is diverted from line 64 via line 26 as a hot hydrogen-containing stream (ie, hot recirculation or hot hydrogen recycle) for supply to the hydrogen gas. Preferably at least 1 by weight
0%, most preferably 25 to 75%, is recycled to the first reactor in this manner. The remainder of the reactor effluent is passed to heat exchanger 66 where the sensible heat of the effluent is utilized to heat the combined hydrocarbon stream in line 12 containing the fresh feed. The reactor effluent in line 42 from heat exchanger 66 is passed to air cooler 68 and water cooler 7 prior to separation as described above in separator 40.
Cool further by 0.

The advantages of the invention can be appreciated in a number of ways. An important concept in the overall configuration is that some or all of the hydrogen used in the desorption step, depending on the particular configuration used,
It is to be fed as hot recycle from either the reactor effluent or the desorption effluent to the adsorber bed for adsorption.

The term “hot recycle” or “hot hydrogen recycle” means
refers to a hydrogen-rich gas that has been preheated for that purpose and is utilized to improve the thermal efficiency of subsequent operations. It is also noted that the present invention applies to partial recycling methods such as those described in U.S. Patent Application Serial No. 879.909, filed June 1, 1986, incorporated herein by reference. Should.

As discussed above, the high temperature recycle of the present invention does not involve separation of components, but is simply a single stream, or splitting of streams. One of the primary purposes of the high temperature recirculation is to provide the necessary hydrogen for the adsorption step and to prevent coking of the catalyst when the desorption effluent reaches the reactor. In addition to supplying the necessary hydrogen, the hot recycle also carries a substantial portion of the reactor effluent that must eventually be recycled to the adsorption device. This mode of operation reduces the need for process cooling and process heating that would otherwise be necessary. Note that the amount of hot recycle must be balanced between maximizing the hydrocarbon reactor effluent that is recycled and minimizing the amount of hydrogen that is recycled. Should. (Maximizing hydrocarbon recirculation reduces energy consumption and minimizing water damage circulation increases adsorption capacity).

This hot recycle is the D
1 Different from recycled materials. Whereas the presence of hydrogen in the D1 recycle is undesirable, in the present invention
Its main purpose is to supply hydrogen. Additionally, the hot recycle in the embodiments of Figures 1.2 and 4 of the present invention originates from the reactor and not from the adsorption unit as in conventional TIPs. This process is similar to the partial recirculation method described earlier and the conventional DI
This differs from the reactor effluent recycle used in P. This is because the purpose of these steps is to recycle the hydrogen-free adsorber feed.

At least two further variations are possible when considering the reactor lead arrangement. In this case, it may be even more advantageous to maintain the flow through the catalyst (beds C1 and C2) in one direction rather than alternating between both directions as illustrated in the arrangement of FIG. can. FIG. 2 illustrates one way in which the above can be accomplished with a single valve manifold that alternates flow through beds CI and C2 but maintains flow in the same direction through adsorbent beds ADS and DBS. Side draw ports (s id
Other methods are also possible, such as edraw port).

A third variation of the reactor lead arrangement is to combine two reactor compartments (cI and C2) in one vessel. This configuration can be used in cases where it is impractical to use a composite bed method for several reasons. Third
The diagram shows a larger reactor, then adsorption (ADS),
It is then shown that there is one feed path via desorption with hydrogen (DBS). In this case, the desorption effluent rather than the reactor effluent provides hot hydrogen recycle.

FIG. 4 achieves the advantages of the present invention, yet is characterized by a two-stage adsorber cycle and the use of hot recycle, where the hot recycle provides substantial cooling and separation of components. Instead, the reactor effluent is used as part of the adsorber feed. Fresh feed in line 110 is combined with reactor hydrocarbon product from line 114 in line 112. The combined hydrocarbon stream is heated by indirect heat exchange with the adsorption effluent carried by line 116 in a heat exchanger 118 from which the combined hydrocarbons are passed to a furnace 120; The hydrocarbons are then heated sufficiently to move to adsorption zone WJ122.

The flow of adsorber feed in line 124 connects to furnace 120
is formed by combining a stream of hot hydrocarbons from a high temperature reactor effluent containing hydrogen and hydrocarbon components. A suitable control valve and control device (not shown)
Directing the flow of adsorber feed to the appropriate bed (here shown as bed 122) in the adsorption compartment.

An adsorber feed containing normal and non-normal hydrocarbons in vapor state is periodically subjected to pressures above atmospheric pressure, such as through each of two fixed adsorber beds as shown in FIG. Pass them sequentially. It is of course possible to use a larger number of beds if desired. However, it is an advantage of the present invention that only two are required.

In a two-bed system, each bed cyclically performs the two stages (ADS and DBS) described with respect to FIG.

Again for the individual adsorption compartments, the bed 122 performs adsorption;
The operation for attaching and detaching the floor 128 will be described in detail below. ”
A portion of the adsorber feed from line 124 is routed to a suitable line.
Flow of adsorber feed through line 124, via manifolds and valves, to an adsorbent bed 122 where adsorption occurs, first flushes a bed 122 of purge gas containing residual hydrogen, and the adsorbent feed is adsorbed. An adsorption effluent is produced that flows continuously through bed 122 and is withdrawn via line 116.

As adsorption continues, normality in the feed exits through appropriate valve and manifold equipment (not shown). The adsorption effluent is transferred to line 116, heat exchanger 118, and air cooler 132.
and through heat exchanger 134 before being separated into a hydrogen-containing overhead product for recycle and an isomerized product in separator 136.

The overhead gas that may be recovered by separator 136 is combined with a similar overhead product from separator 140. Separator 140 separates the reactor effluent takeoff in line 142 from the overhead product collected in line 144 and the reactor hydrocarbons withdrawn via line 114 as described above. separates into the product. The combined stream formed from lines 138 and 144 is fed via line 146 to recirculation compressor 148 and returned via line 150 to the adsorption section for desorption of bed 128.

A flow of hydrogen-containing purge gas from the compressor 148 flows into the line 15.
0 to a heat exchanger 152 and heater 154 where the hydrogen-containing purge gas stream is heated and then passed to bed 128 where desorption takes place.

Effluent from bed 128 passes through appropriate valves and manifolds (not shown) via line 158 to reactor 160. During the desorption stage, the void space adsorber feed is first purged and then the selectively adsorbed normal paraffins are desorbed from the zeolitic molecular sieve. The desorption effluent from bed 128 contains hydrogen and hydrocarbons throughout the stage. The desorption effluent is routed via line 158 to isomerization reactor 160;
Sent as reactor feed.

The above description is based on the single adsorber stage time of the entire two-stage cycle for the system.
period). For the next adsorber stage time, the appropriate valves are operated so that bed 12B begins adsorption and bed 122 begins desorption. Similarly, a new cycle is started after each adsorber stage time: at the end of two cycle times, both seats complete the adsorption and desorption stages.

Supplemental hydrogen can be supplied as required, for example via line 162. The desorption effluent in line 158 includes desorbed hydrocarbons such as n-pentene, n-hexane, hydrogen, light hydrocarbons, and other impurities including the purge gas used for desorption.

This effluent is the reactor feed and isomerization reactor 160
passed through.

Effluent from reactor 160 flows via line 164. A portion of the reactor effluent is routed via line 126 to line 1.
64 as hot hydrogen recycle for feed to the adsorbent bed where adsorption takes place. 100% of reactor effluent
can be recycled in this manner to the adsorbent bed where the adsorption takes place. Preferably at least 10
%, most preferably 25-75%, is recycled. The remainder of the reactor effluent is then passed to heat exchanger 166 where the sensible heat of the effluent is used to heat the combined hydrocarbon stream in line 112. The hydrocarbon stream includes fresh feed. from the heat exchanger 166,
The reactor effluent in line 142 is further cooled by air cooler 168 and water cooler 170 before being separated in separator 140 as discussed above.

It is an advantage of the present invention that existing TIP equipment can be modified to greatly increase feed throughput and final product production while still obtaining sufficient octane for use as a gasoline blendstock. be.

The following examples serve to illustrate and explain the invention, but are not intended to limit it in any way. Unless otherwise indicated, all parts and percentages are on a molar basis.

Example 110 - This example is primarily based on a feed rate of 40,008 PSD of the process operation shown in FIG.

The starting point is selected at the discharge stream from the recirculating hydrogen compressor 148. This stream is worked up with reactor effluent (stream 142) in heat exchanger 152. The hydrogen recycle effluent temperature from 152 is maintained below 358 to control the hydrogen recycle flow bypassing heat exchanger 152 .

The recycle gas is then heated to 510 degrees Fahrenheit in furnace 154. From 154, hot hydrogen flows downward through one adsorber (in this case 128) to strip adsorbed (normal) positive hydrocarbons from the molecular sheep adsorbent. The hot desorption effluent (stream 158) is then sent to isomerization reactor 160. The composition of this stream is shown in the table.

In the isomerization reactor, some normal paraffins are
Converted to isoparaffins. An improved distribution of isohexane is achieved by increasing the concentration of more branched dimethylbutane. Ring opening to the extent of naphthenes, hydrogenation of aromatics, and cranking of hydrocarbons to butane and lighter compounds also occur. The reactor effluent is divided into two streams, with one stream (stream 126) joining the adsorber (device) feed stream and the other stream of reactor effluent being stream 166.
It is cooled by heat exchange with the cold adsorber feed stream and recirculated hydrogen stream 152 within. The reactor effluent removal stream is further cooled to 140°F in air cooler 168 and to 10°F in water cooler 170.
Cooled down to below 0. This removed stream is then sent to reactor effluent separator 140 for separation of condensed hydrocarbons.

The steam from 140 is routed to the inlet of compressor 148, which converts the steam from 220 psig to 301 psig.
Compressed to psig. The condensate from 140 is pumped through line 114 by pump 141 and mixed with fresh feed stream (stream 11O) in line 112 with the eductate (stream 116) and reactor effluent in heat exchanger 166. It is heated by the removal stream and sent to the furnace at an inlet temperature of 395'F. In this furnace 120, the mixed hydrocarbons are heated to below 510°C to a required temperature of 500"F at the adsorber inlet. This feed stream is then combined with the hot recycle stream in line 126 to remove all adsorption. A feed stream (stream 124) is formed in one of the two adsorbers (in this case) depending on the location of the circulation.

122) in which the positive hydrocarbons are adsorbed into the pores of the molecular sieve adsorbent. Hydrocarbons and a small amount of substituted hydrogen gas pass through the bed to form an adsorbent effluent. This adsorption effluent (stream 116) is cooled by the adsorber feed stream in heat exchanger 118. Then,
The adsorption effluent is air cooled at 132 to below 140 and water cooled at 134 to the temperature of the adsorption effluent receiver 166. Top distillate vapor from separator 136 (stream 138) is combined with top distillate vapor from separator 140 and sent to the inlet of compressor 148. The condensed hydrocarbons from separator 136 and the unstabilized isomerate (stream 137) are sent to a stabilization facility. Makeup hydrogen is supplied to separator 136 as needed.

Two adsorbers (122 and 128) containing molecular sieve adsorbents are used to separate normal paraffins from normal hydrocarbons in the feedstock. These adsorbers are attached to adsorber manifolds (not shown). It is automatically cycled from step to step by a controller that operates a remotely operated valve (ROV). At any given time, both adsorbers are involved in the adsorption step, ie, one adsorber is involved in the adsorption step and the other adsorber is involved in the desorption step. 2
Two cycle timers are set to provide the desired process time. The planned process time is as follows.

Adsorption process 110 seconds Desorption process
90 seconds valve switching
40 Seconds Total Cycle Time 240 Seconds Adsorber Feed Stream 124 enters the adsorber participating in the adsorption process. The other adsorber is involved in the desorption process. At the end of the desorption step, the desorption feed stream bypasses the adsorber entirely and reaches the inlet of the isomerization reactor 160. The adsorber that has just finished the desorption process begins the adsorption process, and the other adsorber finishes the adsorption process.

Thus, during a short period of time (20 min during valve switching in a 4 minute cycle)
Sec) Both adsorbers are involved in the adsorption process.

At the beginning of the adsorption process, the adsorber feed and effluent valves are open to one bed and closed to the other bed.

The adsorber feed stream is fed to a molecular sieve adsorbent bed that has been previously purged with hydrogen at approximately 500"F and 256 ρsia. The molecular sieve bed contains synthetic zeolite crystals with interconnecting pores of varying sizes. The pore size of the molecular sheep crystal is sized to only accept molecules with a minimum effective diameter of up to 5 angstroms. Since they are too large to enter the main adsorption site through the pores, only the positive hydrocarbons are adsorbed onto the bed.The positive hydrocarbons remain in the void space of the bed, forcing the purge gas out of the top of the adsorber and into the adsorption manifold. .

As the adsorption process continues, the unpressurized hydrocarbon/purge gas interface reaches the top of the adsorber. The composition of the adsorption effluent changes from being mostly purge gas to being mostly axenic hydrocarbons and hydrogen.

The adsorber feed stream continues to pass upstream through the adsorber and positive hydrocarbons continue to be adsorbed onto the bed. The amount of positive hydrocarbon adsorbed per unit of molecular sieve approaches an equilibrium level determined by the partial pressure and molecular weight of the positive hydrocarbon and the adsorption temperature. This relationship is illustrated by plotting the equimixture of the load (charging) versus the partial pressure. The solid hydrocarbons and hydrogen in feed stream 4 flow from the top of the adsorber into the adsorption effluent manifold along with some purge gas and a small amount of positive hydrocarbons. The positive hydrocarbons adsorbed on the bed displace approximately 15% of the vessel's void volume of purge gas through the pores.

This gas gradually mixes with the hydrocarbons and passes into the adsorption effluent. During the desorption process, the purge gas achieves a residual load of positive hydrocarbons at the top of the adsorber that is in equilibrium with the positive hydrocarbon concentration in the vapor. Since the above equilibrium is reached during the adsorption process, the minimum concentration of positive hydrocarbons in the adsorber effluent is the same as the concentration in the purge gas. As positive hydrocarbons are adsorbed from the incoming adsorber feed stream, the released heat of adsorption creates a temperature front that moves up the bed in coincidence with the adsorbed mass transfer front. Before the mass transfer front reaches the top of the bed (approximately 90% bed utilization), the adsorption step ends, thereby forcing a high concentration of positive hydrocarbons into the adsorption effluent, reducing the purity of the isomerate. prevent it from happening.

During the beginning of the desorption step, the unadsorbed C4+ hydrocarbons retained in the bed after the end of the adsorption step are driven away countercurrently by the hydrogen purge gas. The expelled hydrocarbons flow from the bottom of the bed to the isomerization reactor along with some purge gas.

The purge gas then desorbs the positive hydrocarbons from the adsorbent by lowering the partial pressure of the positive hydrocarbons in the vapor phase, thereby shifting the equilibrium load to a lower value. The concentration of normal pentane and normal hexane in the purge gas is kept at a low level to ensure sufficient desorption of adsorbed hydrocarbons. As the desorption process progresses, the loading of positive hydrocarbons on the bed decreases and the rate at which positive hydrocarbons leave the bed decreases. The desorption step ends before all positive hydrocarbons are removed from the bed. The amount removed during each cycle is based on the economic balance between adsorber bed investment and purge gas recirculation costs.

After the desorption process is completed, the desorption feed stream and effluent valves are closed and the desorption feed flow bypass valve is opened. The bed then returns to the adsorption step and continues the steps listed above in sequence.

In the isomerization reactor, the normal paraffins are partially converted to isoparaffins. A higher octane distribution of isohexane is also achieved by increasing the relative concentration of dimethylbutane. Ring opening to the extent of naphthenes, hydrogenation of aromatics, and cranking of the feed stream to butane and lighter compounds also occur. Reactor performance (ie, conversion and yield) is determined by space velocity, feed stream composition, operating temperature, and hydrogen partial pressure.

The foregoing description is for the purpose of teaching those skilled in the art how to carry out the invention, and is intended to teach those skilled in the art how to carry out the invention and, upon reading the description, to reflect all obvious modifications and variations of the invention. It is not intended to be detailed. However, all such modifications and variations are included within the scope of the invention as defined by the claims.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of the reactor leading process and equipment arrangement. 2 and 3 are system diagrams showing other specific examples of FIG. 1. FIG. 4 is a system diagram of the adsorption device leading process and device arrangement of the present invention.

Claims (1)

[Claims] 1. Containing non-normal hydrocarbons and normal hydrocarbons including normal hexane and normal pentane, produced by a combinatorial isomerization/adsorption method in either an adsorption device leading arrangement or a reactor leading arrangement. In a method of increasing the non-normal content of a hydrocarbon feed: (a) passing a stream of adsorber feed comprising hydrogen and hydrocarbons through an adsorber bed to adsorb normal hydrocarbons from said feed; and discharging non-normal hydrocarbons and hydrogen from the adsorbent bed as an adsorption effluent; (b) passing a hydrogen-containing purge gas through the adsorption bed containing adsorbed normal hydrocarbons to remove hydrogen and normal hydrocarbons; and (c) passing at least a portion of said desorption effluent through an isomerization reactor to produce hydrogen and reactor hydrocarbons, including non-normal and normal hydrocarbons. producing a reactor effluent containing the components. 2. The adsorber feed stream is formed by mixing a hot hydrogen-containing process stream and a hydrocarbon-containing process stream without any substantial cooling of the hydrogen-containing stream prior to mixing. the method of. 3. The process of claim 1, wherein the adsorber feed contains 10 to 90 mole percent hydrogen. 4. The process of claim 3, wherein the adsorber feed contains 30 to 65 mole percent hydrogen. 5. The process of claim 4, wherein the adsorber feed contains 45 to 55 mole percent hydrogen. 6. The process of claim 1, wherein the adsorber feed stream includes a hydrocarbon feed and recycle from the reactor bed containing hydrogen and hydrocarbons. 7. The method of claim 1, wherein the adsorber feed stream includes reactor effluent. 8. The method of claim 7, wherein the adsorber feed stream comprises reactor effluent. 9. The method of claim 8, wherein the adsorber feed contains 30 to 65 mole percent hydrogen. 10. The process of claim 9, wherein the process is carried out in two combined beds, each having a catalyst compartment and an adsorption compartment. 11. A method for improving the octane quality of a hydrocarbon feed containing non-normal hydrocarbon compounds and normal pentane and normal hexane by a combined isomerization and adsorption method in an adsorption device lead arrangement: (a) hydrogen and said carbonization; passing a stream of adsorbent feed comprising a hydrogen feed through an adsorbent bed to adsorb normal hydrocarbons from the feed and discharging non-normal hydrocarbons from the adsorbent bed as adsorption effluent; (b) ) passing a hydrogen-containing purge gas through the adsorber bed containing adsorbed normal hydrocarbons to produce a desorption effluent comprising purge gas and normal hydrocarbons; then (c) isomerizing the desorption effluent; said method comprising passing through a reactor to produce a reactor effluent that includes a purge gas and a reactor hydrocarbon product that includes non-normal and normal hydrocarbons. 12. The method of claim 11, wherein the adsorber feed contains 10 to 90 mole percent hydrogen. 13. The method of claim 12, wherein the adsorber feed contains 30 to 65 mole percent hydrogen. 14. The method of claim 13, wherein the adsorber feed contains 45 to 55 mole percent hydrogen. 15. The method of claim 11, wherein a portion of the reactor effluent and a hydrocarbon stream comprising the hydrocarbon feed are combined to form an adsorption unit feed stream. 16. The process of claim 15, wherein a portion of the reactor effluent and the hydrocarbon stream are combined at a temperature substantially obtained from the reactor without cooling and separation of the components. 17. In a method for improving the octane quality of a hydrocarbon feed containing non-normal hydrocarbons and normal pentane and normal hexane by a combined isomerization and adsorption process in a reactor leading configuration: (a) as set forth below. The reactor feed, including the feed stream and the desorption effluent, is passed through an isomerization reactor to remove at least a portion of the normal hydrocarbons in the reactor feed from the reactor to the reactor. (b) converting at least a portion of said reactor effluent containing hydrogen and hydrocarbons to non-normal hydrocarbons which are withdrawn in the effluent; (c) passing a hydrogen-containing purge gas through the adsorber bed containing the adsorbed normal hydrocarbons; producing said desorption effluent comprising hydrogen and normal hydrocarbons; and then (d) passing at least a portion of said desorption effluent through said isomerization reactor. 18. The method of claim 17, wherein the adsorber feed contains 10 to 90 mole percent hydrogen. 19. The method of claim 18, wherein the adsorber feed contains 30 to 65 mole percent hydrogen. 20. The method of claim 19, wherein the adsorber feed contains 45 to 55 mole percent hydrogen. 21. The process of claim 17, wherein at least a portion of the desorption effluent is combined with the hydrocarbon feed stream and then passed through the reactor without separation of the hydrogen and normal hydrocarbon components. 22. A method for improving the octane quality of a hydrocarbon feed containing non-normal hydrocarbons and pentane and hexane by a combined isomerization and adsorption process in a reactor leading configuration, comprising: (a) combining the hydrocarbon feed with hydrogen; passing a reactor feed comprising a first isomerization catalyst bed to discharge at least a portion of the normal hydrocarbons in the reactor feed from the bed as a first reactor effluent. converting the first reactor effluent to non-normal hydrocarbons; (b) passing the first reactor effluent through an adsorption device bed to adsorb the normal hydrocarbons and discharging the non-normal hydrocarbons as an adsorption effluent; (c) (d) passing a hydrogen-containing purge gas through the adsorber bed containing adsorbed normal hydrocarbons to produce a desorption effluent comprising hydrogen and normal hydrocarbons; converting at least a portion of the normal hydrocarbons in the desorption effluent to non-normal hydrocarbons, and converting the non-normal hydrocarbons into a second reactor effluent through a second isomerization catalyst bed. the method comprising: discharging the catalyst bed. Claim 23. At least a portion of the second reactor effluent and the hydrocarbon feed are combined prior to substantial cooling.
The method described in 2. 24. The process of claim 22, wherein the complete circulation includes two passes through each catalyst bed, with the flow reversing after each pass. 25. The method of claim 24, wherein the catalyst bed and the desorption bed are contained within one vessel. 26. The method of claim 22, wherein the complete circulation includes two passes through each catalyst bed, and the flow is in the same direction for each pass. 27. The process of claim 22, wherein hydrogen comprises 10 to 90 mole percent of the first reactor effluent. 28. The process of claim 27, wherein hydrogen comprises 30 to 65 mole percent of the first reactor effluent. 29. The process of claim 28, wherein hydrogen comprises 45 to 50 mole percent of the first reactor effluent. 30. The process of claim 29, wherein the complete circulation includes two passes through each catalyst bed, and the flow is reversed after each pass. 31. The method of claim 30, wherein the catalyst bed and the adsorber bed are contained within one vessel. 32. Non-normalization of hydrocarbon feeds containing non-normal hydrocarbons and normal hydrocarbons, including normal hexane and normal pentane, by a combined isomerization and adsorption process in either an adsorption device-directed configuration or a reactor-directed configuration. In a content increasing apparatus: (a) an adsorbent bed capable of selectively adsorbing normal hexane and normal pentane; (b) a stream of adsorbent feed containing hydrogen and hydrocarbons to the adsorbent bed; (c) means for adsorbing normal hydrocarbons from said feed through the feed and discharging non-normal hydrocarbons and hydrogen from the adsorber bed as an adsorption effluent; (c) a hydrogen-containing purge gas containing the adsorbed normal hydrocarbons; means for passing the adsorber bed to produce a desorption effluent containing hydrogen and normal hydrocarbons; (d) an isomerization reactor containing a catalyst capable of isomerizing normal hexane and normal pentane; and ( e) means for passing at least a portion of said desorption effluent through an isomerization reactor to produce a reactor effluent comprising hydrogen and a reactor hydrocarbon component comprising non-normal and normal hydrocarbons; The device comprising; 33. means for forming an adsorption unit feed stream by mixing a hot hydrogen-containing process stream and a hydrocarbon-containing process stream without any substantial cooling of said hydrogen-containing stream prior to mixing; 33. Apparatus according to claim 32, provided in: 34. The apparatus of claim 33, wherein the adsorber feed contains 10 to 90 mole percent hydrogen. 35. The apparatus of claim 34, wherein the adsorber feed contains 30 to 65 mole percent hydrogen. 36. The apparatus of claim 35, wherein the adsorber feed comprises 45 to 55 mole percent hydrogen. 37. The process of claim 32, wherein the adsorber feed stream includes a hydrocarbon feed and recycle from the reactor bed containing hydrogen and hydrocarbons. 38. The apparatus of claim 32, wherein the adsorber feed stream includes reactor effluent. 39. The apparatus of claim 38, wherein the adsorber feed stream comprises reactor effluent. 40. The apparatus of claim 39, wherein the adsorber feed comprises 30 to 65 mole percent hydrogen. 41. The apparatus of claim 40, comprising two combined beds, each having a catalyst compartment and an adsorption compartment. 42. In an apparatus for improving the octane quality of a hydrocarbon feed containing non-normal hydrocarbon compounds and normal pentane and normal hexane by a combined isomerization and adsorption method in an adsorption apparatus lead arrangement: (a) normal hexane; (b) passing an adsorbent feed stream containing hydrogen and said hydrocarbon feed through the adsorbent bed to remove normal hydrocarbons from said feed; (c) passing a hydrogen-containing purge gas through said adsorbent bed containing the adsorbed normal hydrocarbons to form the purge gas and normal carbonization; means for producing a desorption effluent comprising hydrogen; (d) an isomerization reactor containing a catalyst capable of isomerizing normal hexane and normal pentane; and (e) isomerizing said desorption effluent. Pass through the reactor,
means for producing a reactor effluent comprising a purge gas and a reactor hydrocarbon product comprising non-normal and normal hydrocarbons. 43. At temperatures obtained from the reactor without substantial cooling or separation of the components, a portion of the reactor effluent and the hydrocarbon stream, including the hydrocarbon feed, are combined and adsorbed. 43. The apparatus of claim 42, further comprising means for forming a flow of apparatus feed. 44, in an apparatus for octane upgrading of hydrocarbon feeds containing non-normal hydrocarbons and normal pentane and normal hexane by a combined isomerization and adsorption process in a reactor leading configuration: (a) normal hexane and normal hexane; an isomerization reactor containing a catalyst capable of isomerizing normal pentane; (b) a reactor feed comprising said feed stream and a desorption effluent as described below; (c) means for converting at least a portion of the normal hydrocarbons in the reactor feed into non-normal hydrocarbons which are withdrawn from the reactor into the reactor effluent; passing at least a portion of said reactor effluent containing said reactor effluent as an adsorbent feed to an adsorbent bed without substantial cooling to adsorb normal hydrocarbons, and to adsorb hydrogen and non-normal hydrocarbons as an adsorbent effluent; (d) an adsorbent bed capable of selectively adsorbing normal hexane and normal pentane; (e) means for discharging hydrogen-containing purge gas through said adsorbent bed containing adsorbed normal hydrocarbons; (f) means for passing at least a portion of said desorption effluent to said isomerization reactor; and (f) means for passing at least a portion of said desorption effluent to said isomerization reactor. Said device. 45, further comprising means for combining at least a portion of the desorption effluent and a hydrocarbon feed stream and then passing the combined stream to the reactor without separation of the hydrogen and hydrocarbon components. 44. The apparatus of claim 43. 46, in an apparatus for octane upgrading of a hydrocarbon feed containing non-normal hydrocarbons and pentane and hexane: (a) a first catalyst containing a catalyst capable of isomerizing normal pentane and normal hexane; (b) passing a reactor feed comprising a hydrocarbon feed and hydrogen through a first isomerization catalyst bed to remove at least a portion of the normal hydrocarbons in said reactor feed; means for converting the bed to non-normal hydrocarbons which are discharged as a first reactor effluent; (c) an adsorbent bed comprising an adsorbent capable of selectively adsorbing normal pentane and normal hexane; d) means for passing said first reactor effluent through an adsorption device bed to adsorb normal hydrocarbons and to discharge non-normal hydrocarbons as an adsorption effluent; (e) a hydrogen-containing purge gas; means for passing said adsorber bed containing adsorbed normal hydrocarbons to produce a desorption effluent comprising hydrogen and normal hydrocarbons; (f) a second catalyst bed; and (g) said desorption effluent; The effluent is passed through a second isomerization catalyst bed to remove at least a portion of the normal hydrocarbons in the desorption effluent from the second catalyst bed, which is discharged as a second reactor effluent. means for converting to normal hydrocarbons.