CLIAMS:1. A process for producing linear alkyl benzene (LAB) and recovering normal paraffins from a kerosene stream, said process comprising following steps:
a. adding a solution of urea in a first fluid medium containing an activator to a kerosene stream comprising a co-boiling mixture of a hydrocarbon component, nitrogen components and sulfur components; wherein the hydrocarbon component comprises a mixture of normal olefins, non-normal olefins, normal paraffins, non-normal paraffins, cycloparaffins and aromatics; and wherein the co-boiling kerosene stream has boiling point in the range of the boiling point of normal olefins and the boiling point of normal paraffins; followed by stirring to obtain a first suspension;
b. allowing the first suspension to settle to obtain a first precipitate comprising urea adducts of the normal olefins, normal paraffins, the nitrogen components and the sulfur components present in the kerosene stream, and a first supernatant containing the fraction of the kerosene stream that did not form an adduct with urea, the first fluid medium and the activator;
c. separating the first precipitate and the first supernatant;
d. washing the separated first precipitate with a first washing medium to obtain a washed first precipitate; and recycling the first washing medium after filtration for washing separated first precipitate;
e. treating the washed first precipitate with a deadducting medium containing benzene to obtain a second suspension and allowing the second suspension to settle;
f. separating the settled second suspension to obtain a second precipitate containing urea and a second supernatant containing normal olefins, normal paraffins, the nitrogen components and the sulfur components in the deadducting medium;
g. washing the second precipitate with a second washing medium to obtain urea as a residue and a filtrate comprising the second washing medium;
h. mixing the second supernatant and benzene to obtain a fluid mixture;
i. subjecting the fluid mixture comprising normal olefins, normal paraffins, the nitrogen components, the sulfur components, the deadducting medium and benzene to alkylation in the presence of a catalyst selected from a group consisting of metal salt based ionic liquids and sulfonic acids, wherein at least a portion of benzene, the sulfur components and the nitrogen components react with normal olefins present in the fluid mixture while the normal olefins remain unreacted, to obtain a reaction mixture comprising linear alkyl benzene (LAB), alkylated sulfur components, alkylated nitrogen components and unreacted normal paraffins;
j. allowing the reaction mixture to settle and form a biphasic mixture comprising a lighter phase containing the linear alkyl benzene (LAB), heavy alkyl benzene (HAB), unreacted benzene, the alkylated sulfur components, the alkylated nitrogen components and the unreacted normal paraffins, and a heavier phase containing the catalyst; followed by separation of the lighter phase and heavier phase of the biphasic mixture;
k. deacidification of the separated lighter phase to obtain a deacidified lighter phase; and
l. fractionally distilling the deacidified lighter phase to obtain distinct fractions of unreacted benzene, normal paraffins, linear alkyl benzene and heavy alkyl benzene.
2. The process as claimed in claim 1, wherein the kerosene stream is at least one selected from the group consisting of coker light light coker gas oil (LLCGO), coker light coker gas oil (LCGO), fluid catalytic cracker (FCC) naphtha, FCC kero, FCC gas oil, straight run naphtha, and straight run kero; wherein the kerosene stream comprises C6 to C20 hydrocarbons.
3. The process as claimed in claim 1, wherein the amount of the normal paraffins in the kerosene stream ranges from 1 to 20 % on mass basis.
4. The process as claimed in claim 1, wherein the first fluid medium is at least one selected from the group consisting of water, methanol and acetone; and the activator is at least one selected from the group consisting of methanol and acetone.
5. The process as claimed in claim 1, wherein the deadducting medium further comprises at least one fluid medium selected from the group consisting of benzene, toluene, decane, dodecane and acetone.
6. The process as claimed in claim 1, wherein the sulfonic acid is RSO3H; wherein R is selected from a group consisting of alkyl groups, aryl groups and halogens.
7. The process as claimed in claim 1, wherein the metal salt based ionic liquid is selected from a group consisting of metal salt based ionic liquids of Formula-I and Formula-II;
MXn-A - (I);
wherein, M is a metal selected from a group of metals consisting of Al, Fe, Zn, Mn, Mg, Ge, Cu and Ni;
X is a halogen selected from F, Cl, Br and I;
n is a number in the range from 1 to 3; and
A is an anionic component selected from a group consisting of quaternary ammonium, cholinium, sulfonium, phosphonium, guanidinium, imidazolium, pyridinium and pyrolidium; and
[(NR1R2R3)iM1]n+[(M2Yk)L Xj]n- - (II)
wherein; NR1R2R3 is an amine; wherein, R1, R2, and R3 are independently selected from hydrogen and alkyl groups selected from a group consisting of methyl, ethyl, propyl and butyl;
M1 and M2 are metals selected from a group of metals consisting of Al, Fe, Zn, Mn, Mg, Ge, Cu and Ni;
n, i, j, k and L are numbers independently selected from 1 to 10; and
X and Y are halogens selected from F, Cl, Br and I.
8. The process as claimed in claim 1, wherein the alkylation is carried out at a temperature in the range from 5 ?C to 150 ?C and a pressure in the range from 1 atm to 50 atm.
9. The process as claimed in claim 1, wherein the ratio of the amount of benzene and the amount of olefins in the step (i) is greater than 10:1.
10. The process as claimed in claim 1, wherein the ratio of the amount of the sulfonic acid and the amount of the olefin in the step (i) is in the range from 1:5 to 5:1 and the ratio of the amount of the ionic liquid and the amount of the olefin in the step (i) is in the range from 1:10 to 1:1000. ,TagSPECI:FIELD
The present invention relates to a process for preparing linear alkyl benzene and recovering normal paraffin from a hydrocarbon stream.
BACKGROUND
Linear alkyl benzene (LAB) is prepared on an industrial scale by alkylation of benzene with normal olefins. The normal olefins are often obtained from a hydrocarbon stream, such as a kerosene stream. The hydrocarbon stream also contains normal paraffins, which are useful in various applications.

The kerosene stream contains various co-boiling C6 to C20 hydrocarbon components such as normal olefins, normal paraffins, non-normal olefins and non-normal paraffins, along with aromatics, naphthenes, sulfur and nitrogen impurities. The amount of the normal olefins present in a hydrocarbon stream is referred to as the olefinic value of the hydrocarbon stream.
Traditionally, the kerosene stream is subjected to hydrotreatment in order to saturate the diolefins and to remove the aromatics, naphthenes, sulfur and nitrogen impurities. The presence of unwanted components and impurities, such as the aromatics, naphthenes, sulfur and nitrogen impurities, in the kerosene stream leads to poisoning of the expensive adsorbents and catalysts that are used in subsequent steps. Therefore, in the traditional process, the kerosene stream is first subjected to hydrotreatment.

However, during the hydrotreatment step, the olefins present in the kerosene stream undergo hydrogenation and form paraffins. Thus, the olefinic value of the kerosene stream is lost during the step of hydrotreatment.

A stream containing normal paraffins is separated from the hydrotreated kerosene stream. This can be carried out using molecular sieve adsorbents. The separated normal paraffins are useful for various applications.

The separated stream containing normal paraffins can also be used for the preparation of LAB. The stream is subjected to a step of dehydrogenation during which a portion of the normal paraffins is converted to normal olefins, generating a stream containing normal paraffins and normal olefins. Benzene is mixed with the generated stream and reacted in the presence of hydrofluoric acid (HF) as a catalyst. During this reaction, the normal olefins react with benzene and produce linear alkyl benzene (LAB) and heavy alkyl benzene (HAB).

HF, used as a catalyst for the alkylation step, is highly corrosive. Apart from this, the use of HF requires careful handling and suitable material of construction. Further, HF is very toxic and is environmentally hazardous.

Thus, the existing technology for the production of normal paraffin from the kerosene stream and its subsequent conversion to linear alkyl benzene therefore involves:
(a) a step of hydrotreatment;
(b) separation of normal paraffins;
(c) partial conversion of normal paraffins to normal olefins; and
(d) use of a corrosive and hazardous catalyst.

Therefore, there exists a need to provide a process for the preparation of LAB and recovery of normal paraffins from the kerosene stream that eliminates aforesaid deficiencies.

OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide a process for the preparation of LAB and the recovery of normal paraffins from a kerosene stream.
Another object of the present disclosure is to provide a process for the preparation of LAB and the recovery of normal paraffins from a kerosene stream, wherein the alkylation of benzene is carried out using a catalyst that is environmentally safe and easy to handle.
Other objects and advantages of the present disclosure will be more apparent from the following description which is not intended to limit the scope of the present disclosure.
SUMMARY
In accordance with the present disclosure, there is provided a process for preparation of LAB and recovery of normal paraffins from a kerosene stream.
In the process of the present disclosure, the kerosene stream is not subjected to hydrotreatment. The normal olefins and normal paraffins present in the kerosene stream are separated by the formation of a urea adduct. Other components and impurities that can harm the expensive adsorbents and catalysts remain in the supernatant. The separated urea adduct is decomposed to recover the adducted normal olefins and normal paraffins.
The separated normal olefins and normal paraffins are reacted with benzene in the presence of a catalyst to obtain LAB. Unreacted benzene, LAB, heavy alkyl benzenes (HAB) and unreacted normal paraffins are separated by fractional distillation.
The process of the present disclosure obviates the hydrotreatment step and the dehydrogenation step performed in the conventional process. Further, the use of HF during alkylation is avoided.

DETAILED DESCRIPTION
The existing technology for recovering normal paraffin from the kerosene stream and its use for preparing linear alkyl benzene has several drawbacks. The existing technology involves a step of hydrotreatment which obliterates olefinic value of the kerosene stream. The hydrotreatment is followed by separation of the normal paraffins from the hydrotreated kerosene stream followed by partial conversion of the separated normal paraffins to normal olefins. The resultant mixture of normal paraffins and normal olefins is then used for the alkylation of benzene in the presence of a corrosive and hazardous HF as a catalyst.

In order to overcome these deficiencies, the present disclosure envisages a process without the step of hydrotreatment and use of a non-hazardous or a comparatively less hazardous catalyst. In the process of the present disclosure, the normal olefins and normal paraffins are separated from the kerosene stream by adduct formation using urea followed by separation and decomposition of the urea-adduct. The separated mixture of normal olefins and normal paraffins are reacted with benzene in the presence of an ionic liquid or a sulfonic acid as a catalyst, which is a comparatively less corrosive or non-corrosive catalyst and safe to use as compared to HF.
In accordance with one aspect of the present disclosure, there is provided a process for producing linear alkyl benzene (LAB) and recovering normal paraffins from a kerosene stream.
Sulfonic acids are less hazardous and less corrosive as compared to HF. The ionic liquids exhibit very low to negligible vapor pressure. In contrast to many conventional acidic catalysts and molecular solvents, the ionic liquids either do not produce vapors or produce negligible amount vapors, which make them non- hazardous. The ionic liquids are safe to handle and do not need special safety precautions as in case of HF. The ionic liquids used in the process of the present disclosure are non-toxic and environmentally safe.
The process of the present disclosure involves the following steps:
The first step is adding a solution of urea in a first fluid medium containing an activator to a kerosene stream comprising a co-boiling mixture of a hydrocarbon component, nitrogen components and sulfur components, followed by stirring to obtain a first suspension. The hydrocarbon component of the kerosene stream comprises a mixture of normal olefins, non-normal olefins, normal paraffins, non-normal paraffins, cycloparaffins and aromatics. The co-boiling kerosene stream has boiling point in the range of the boiling point of the normal olefins and the boiling point of the normal paraffins.
The first fluid medium is at least one selected from the group consisting of water, methanol and acetone. The activator is at least one selected from the group consisting C1 to C6 alcohols, water, methanol and toluene.
In accordance with the embodiments of the present disclosure, the first fluid medium and the activator can be same or different.
During the first step, a fraction of the hydrocarbon components, nitrogen components and sulfur components present in the kerosene stream form adducts with urea and precipitates. The other fraction of the hydrocarbon component, the nitrogen components and the sulfur components do not form adducts with urea and remains in the supernatant.
The second step involves allowing the first suspension to settle to obtain a first precipitate and a first supernatant. The first precipitate comprises urea adducts of the normal olefins, normal paraffins, nitrogen components and sulfur components present in the kerosene stream. The first supernatant contains the fraction of the kerosene stream that did not form adduct with urea, the first fluid medium and the activator.
The third step is separating the first precipitate from the first supernatant. The separation can be carried out by filtration or centrifugation.
The first precipitate is used for the next step, whereas, the separated first supernatant is allowed to settle. On settling, it forms two phases, a top phase and a bottom phase. The bottom phase contains a mixture of the first fluid medium, the activator and dissolved urea. This bottom phase is recycled to the first step as the solution of urea in the first fluid medium containing the activator. The top layer contains un-adducted fraction of the kerosene stream. This top phase is used for suitable applications such as blending with diesel after hydrotreatment.
The fourth step involves washing the separated first precipitate with a first washing medium to obtain a washed first precipitate. The filtrate obtained from this step is recycled as a washing medium.
The first washing medium is at least one selected from the group consisting of C4 to C6 linear alkanes, methanol, acetone and C4 to C6 ketones.
The fifth step is treating the washed first precipitate with a deadducting medium containing benzene to obtain a second suspension. After treatment, the second suspension is allowed to settle.
The deadducting medium may further comprise a fluid medium selected from the group consisting of aromatics such as toluene and xylene, polar solvents such as water, dichloromethane, methanol and ethanol, C6-C14 linear alkanes, C6-C14 linear olefins and combinations thereof.
The sixth step is separating the settled second suspension to obtain a second precipitate containing urea and a second supernatant containing normal olefins, normal paraffins, the nitrogen components and the sulfur components in the deadducting medium.
Thus, during the process of the present disclosure, the amount of normal olefins present in the kerosene stream, also known as its olefinic value, remain unaltered, while the impurities are separated from the normal paraffins and normal olefins.
This is in contrast to the process involving hydrotreatment, which converts the normal olefins to normal paraffins. In order to produce normal olefins, the process involves a partial dehydrogenation step which results in the conversion of the normal paraffins to normal olefins.
The second supernatant contains the deadducting medium used in the fifth step. There is no need to remove of the deadducting medium from the second supernatant since the deadducting medium contains benzene, which reacts in the alkylation step and produce LAB. Due to this feature, the process of the present disclosure is energy efficient.
The seventh step is washing the second precipitate with a second washing medium to obtain urea as a residue and a filtrate comprising the second washing medium.
The urea obtained in the seventh step is recycled for preparation of the urea solution that used in the first step.
The eighth step is mixing the second supernatant obtained in the sixth step with benzene to obtain a fluid mixture.
The ninth step involves subjecting the fluid mixture to alkylation in the presence of a catalyst selected from a group consisting of metal salt based ionic liquids and sulfonic acids. During this step, benzene, the sulfur components and the nitrogen components undergo alkylation with normal olefins present in the fluid mixture, while, the normal paraffins present in the fluid mixture remain unreacted. The alkylation of benzene produces linear alkyl benzene (LAB) and heavy alkyl benzene (HAB). The reaction mixture obtained after the alkylation step comprises LAB, HAB, unreacted benzene, normal paraffin, alkylated sulfur components and alkylated nitrogen components.
The alkylation can be carried out in a reactor selected from the group consisting of, but not limited to, a static mixer, a jet mixer and a pump mixer. The alkylation can be carried out in a single reactor or multiple reactors. When, multiple reactors are used, they may be of the same type or different types.

In accordance with the embodiments of the present disclosure, the alkylation is carried out at a temperature in the range from 5 ?C to 150 ?C and at a pressure in the range from 1 atm to 50 atm.
In accordance with the preferred embodiments of the present disclosure, the alkylation is carried out at a temperature in the range of 20 oC to 80 oC and at a pressure in the range of 1 atm to 10 atm.

The tenth step is allowing the reaction mixture obtained in the ninth step to settle and form a biphasic mixture. The lighter phase of the biphasic mixture contains the linear alkyl benzene (LAB), heavy alkyl benzene (HAB), unreacted benzene, the alkylated sulfur components, the alkylated nitrogen components, the unreacted normal paraffins, and a heavier phase of the biphasic mixture contains the catalyst. The phases of the biphasic mixture are separated to obtain a lighter phase and a heavier phase.
The eleventh step is deacidification of the lighter phase with at least one form of treatment selected from the group consisting of washing with an alkali solution such as a NaOH solution, washing with water, centrifugation, contacting with alumina, and azeotropic distillation, to obtain a deacidified lighter phase.
The deacidified lighter phase is subjected to fractional distillation to obtain distinct fractions of the normal paraffins, linear alkyl benzene (LAB), heavy alkyl benzene (HAB), unreacted benzene, alkylated sulfur components and alkylated nitrogen components.
The heavier phase of the bi-phasic mixture obtained in the tenth step contains the catalyst. The heavier phase of the bi-phasic mixture containing catalyst is recycled to the alkylation step either directly or after regeneration.
In accordance with the embodiment of the present disclosure, the metal salt based ionic liquid used as a catalyst for the alklylation step comprises at least one a metal salt and at least one anionic component.
The metal salt based ionic liquids used for the alkylation step is selected from a group consisting of metal salt based ionic liquids of Formula-I and Formula-II.
MXn-A - (I);
wherein,
M is a metal selected from a group of metals consisting of, but not limited to, Al, Fe, Zn, Mn, Mg, Ge, Cu and Ni;
X is a halogen element selected from F, Cl, Br and I;
n is a number in the range from 1 to 3; and
A is an anionic component selected from a group consisting of quaternary ammonium, cholinium, sulfonium, phosphonium, guanidinium, imidazolium, pyridinium and pyrolidium.
[(NR1R2R3)iM1]n+[(M2Yk)L Xj]n- - (II)
wherein;
NR1R2R3 is an amine; wherein, R1, R2, and R3 are independently selected from hydrogen and alkyl groups selected from a group consisting of methyl, ethyl, propyl and butyl;
M1 and M2 are metals selected from a group of metals consisting of, but not limited to, Al, Fe, Zn, Mn, Mg, Ge, Cu and Ni;
n, i, j, k and L are numbers independently selected from 1 to 10; and
X and Y are halogens selected from F, Cl, Br and I.
In accordance with the embodiments of the present disclosure, M1 and M2 can be the same metal or different metals, and X and Y can be the same halogen or different halogens.

In accordance with the embodiments of the present disclosure, NR1R2R3 is selected from the group consisting of, but not limited to, ammonia, methylamine, ethylamine, dimethylamine, diethylamine, n-propylamine, iso-propylamine, n-butylamine, tert-butylamine, iso-butylamine, ethylmethylamine, di-n-propylamine, di-iso-propylamine, triethylamine, trimethylamine, methyldiethylamine, ethyldimethylamine, tripropylamine, tributylamine, butyldipropylamine, dibutylpropylamine, ethylmethylpropylamine, and butylethylpropylamine.

In one embodiment of the present disclosure, the amine is tri-ethylamine, metal halide is aluminium chloride and the ionic liquid is [(N(C2H5)3Al]+ [Al2Cl7]-3.

The sulfonic acid used as catalyst for the alkylation step is represented by Formula-III,
RSO3H (III);
wherein, R is selected from a group consisting of an alkyl group, an aryl group and a halogen.

In accordance with the preferred embodiments of the present disclosure, the sulfonic acid is selected from a group consisting of methanesulfonic acid, fluorosulfonic acid and perhaloalkylsulfonic acid.

In accordance with one embodiment of the present disclosure, the sulfonic acid used for alkylation is methanesulfonic acid.

The kerosene stream comprises C6 to C20 hydrocarbons. The kerosene stream used in the process of the present disclosure is at least one selected from the group consisting of coker light light coker gas oil (LLCGO), coker light coker gas oil (LCGO), fluid catalytic cracker (FCC) naphtha, FCC kero, FCC gas oil, straight run naphtha and straight run kerosene.
The amount of the sulfur components in the kerosene stream ranges from 0 to 5 % on mass basis. The amount of the nitrogen components in the kerosene stream ranges from 0 to 5% on mass basis. The amount of the normal paraffins in the kerosene stream ranges from 1 to 20 % on mass basis.
The amount of the cycloparaffins in the kerosene stream ranges from 0 to 10 % on mass basis. The amount of the aromatics in the kerosene stream ranges from 0 to 40 % on mass basis. The amount of the non-normal paraffins in the kerosene stream ranges from 0 to 40 % on mass basis. The amount of the branched olefins in the kerosene stream ranges from 0 to 20 % on mass basis. The amount of the normal olefins in the kerosene ranges from 0 to 20 % on mass basis.
The ratio of the amount of benzene and the amount of olefins in the alkylation step is greater than 10:1.
In accordance with one embodiment of the present disclosure, the ratio of the amount of benzene and the amount of olefins in the alkylation step is 11.
The ratio of the amount of the sulfonic acid and the amount of the olefin in the alkylation step is in the range from 1:5 to 5:1.
The ratio of the amount of the ionic liquid and the amount of the olefin in the alkylation step is in the range from 1:10 to 1:1000.
The process of the present disclosure replaces highly corrosive and hazardous HF with less corrosive sulfonic acid or ionic liquid as catalyst for LAB manufacturing. Although, HF has been replaced, the process of the present disclosure can be retrofitted into the existing HF technology equipment without substantial changes in the reactor design.
The second supernatant obtained after the sixth step comprising normal paraffins, normal olefins and deadducting medium can be fractionally distilled to obtain benzene and a fraction containing co-boiling mixture of normal paraffins and normal olefins.
The sulfur component removed from the kerosene stream during the process of the present disclosure is in the range from 50 to 99 % on mass basis.
Examples provided herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The laboratory scale experiments provided herein can be scaled up to industrial or commercial scale.

EXAMPLE-1:
Preparation of ionic liquid [(N(C2H5)3-Al]+ [Al2Cl7]-3 8.08 gm (0.061 mol) of AlCl3 and 50 ml of ethyl acetate were charged into a reactor maintained under a nitrogen atmosphere and the resultant mixture was stirred. 18.4 gm (0.0182 mol) of triethylamine was added to the above mixture slowly over 30 minutes at 15-20 oC, to obtain a suspension. The suspension was stirred for 4 hours. The suspension was filtered and the separated solids were washed with 100 ml fresh ethyl acetate and dried to get 22 gm of precursor.
15 gm (0.034 mol) of the precursor and 20 ml benzene were charged into a reactor under a nitrogen atmosphere and the content was stirred 10-15 oC. 27.5 gm (0.206 mol) of AlCl3 was slowly added to the reactor over 30 minutes. The resultant mass was stirred for 4 hours to obtain the ionic liquid.
EXAMPLE 2
A kerosene feed containing 7890 ppm sulfur components and 850 ppm nitrogen components was subjected to adduct formation with urea. The adduct was separated from the first supernatant, washed and deadducted. The urea obtained during deadduction step was separated and the second supernatant was used for the next step. The second supernatant was found to have 377 ppm sulfur components and 160 ppm nitrogen components.
754 gm of second supernatant containing 73.5% C10 to C15 normal paraffins and 26.5% C10 to C13 normal olefins was mixed with 1941 gm of benzene in a reactor to obtain a fluid mixture. The fluid mixture was heated to 45 oC and 44 gm of ionic liquid catalyst obtained in example-1 was added to the fluid mixture and the resulting mixture was stirred at the same temperature for 10 mins. The reaction mixture was allowed to settle and form a biphasic mixture. The lighter layer of the biphasic mixture was analyzed by gas chromatography (GC). The conversion of olefins obtained was found to be 99%.
2515 gm of the lighter layer obtained from above step was washed with 2000 gm water at 25-30 oC to obtain deacidified lighter layer.

2365 gm of the deacidified lighter layer obtained above was subjected to fractional distillation. Benzene distilled out as the first fraction and it was followed by fractions containing normal paraffins, LAB and HAB, respectively.

The composition of the second supernatant and the lighter layer obtained after alkylation are shown in Table 1.

Table 1: Composition of the second supernatant and the lighter layer
Component Wt %
Second supernatant Lighter layer
Benzene 72.02 68.72
Olefins 6.89 NIL
Paraffins 21.08 21.08
LAB NIL 8.32
HAB NIL 1.88

During alkylation, the normal olefins present in the fluid mixture of the second supernatant alkylate with benzene and result in the formation of LAB and HAB. The normal paraffins present in the fluid mixture remained unreacted. The LAB, HAB and normal paraffins are separated by fractional distillation.
The LAB fraction obtained after fractional distillation was found to contain 33 ppm sulfur components and 1.6 ppm nitrogen components; whereas the normal paraffins fraction was found to have 48 ppm sulfur components and 2.1 ppm nitrogen components.
The amount of sulfur and nitrogen impurities in the streams at four different stages of the process of the present disclosure is summarized in Table 2.
Table 2: Sulfur and nitrogen components present in the kerosene feed, intermediate and finished product streams
Stream Sulfur components (ppm) Nitrogen components (ppm)
Kerosene Feed 7890 850
Second supernatant 377 160
LAB fraction 33 1.6
Normal paraffin fraction 48 2.1
The kerosene stream contained 7890 and 850 ppm of sulfur and nitrogen components, respectively. After adducting with urea, separation and deadducting steps, the amount of sulfur and nitrogen components in the second supernatant was found to be 377 and 160 ppm, respectively. After the alkylation step and fractional distillation, the sulfur and nitrogen components level dropped significantly. After separation, LAB was found to have 33 and 1.6 ppm nitrogen and sulfur components, respectively, whereas the same for normal paraffins is 48 and 1.6 ppm, respectively.
The amount of sulfur and nitrogen components present in LAB fraction and normal paraffins fraction can be further reduced by employing selective adsorption or mild hydrotreatment.
Therefore, the present disclosure provides a process for producing LAB and n-paraffin without the hydrotreatment step from a stream containing impurities in the form of sulfur and nitrogen components.
TECHNICAL ADVANCEMENT
The technical advancements offered by the present disclosure include the realization of:
1. a process for the recovery of normal olefins and normal paraffins present in a kerosene stream that do not involve the step of hydrotreatment;
2. a process for alkylation of benzene using the recovered normal olefins that uses a catalyst which is less corrosive than HF; and
2. an economical and safe process.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.

Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.