PROCESS FOR REMOVING ALKENE AND/OR ALKYNE FROM A HYDROCARBON FEEDSTOCK

Abstract

The present invention relates to a process for purifying a hydrocarbon feedstock, said process comprising the steps: (a) providing the hydrocarbon feedstock comprising an aromatic compound and at least one compound, selected from the group consisting of alkene, alkyne, nitrogen-containing compound or mixtures thereof; and (b) contacting the hydrocarbon feedstock with an acidic montmorillonite adsorbent at a temperature in the range from 10 to 60 C.

Claims

1. A process for purifying a hydrocarbon feedstock, said process comprising the steps: (a) providing the hydrocarbon feedstock comprising an aromatic compound and at least one compound, selected from the group consisting of alkene, alkyne, nitrogen-containing compound or mixtures thereof; and (b) contacting the hydrocarbon feedstock with an acidic montmorillonite adsorbent at a temperature in the range from 10 to 60 C.

2. The process according to claim 1, wherein the aromatic compound is an aromatic hydrocarbon compound selected from benzene, toluene, xylene, ethylbenzene, their derivatives, and mixtures thereof.

3. The process according to claim 1, wherein the alkene is C4 to C10 alkene.

4. The process according to claim 1, wherein the alkyne is C4 to C10 alkyne.

5. The process according to claim 1, wherein the nitrogen-containing compound is N-formyl morpholine.

6. The process according to claim 1, wherein contacting of the hydrocarbon feedstock with the acidic montmorillonite adsorbent is carried out at a gauge pressure in the range from 0 to 610.sup.6 Pascal.

7. The process according to claim 1, wherein the acidic montmorillonite adsorbent comprises a content of H.sup.+ per gram of adsorbent of at least 1 mol.

8. The process according to claim 7, wherein the acidic montmorillonite adsorbent is obtainable by treating a montmorillonite with an acid.

9. The process according to claim 8, wherein the acid is selected from the group consisting of ammonium sulfate, sulfuric acid, hydrochloric acid, and mixtures thereof.

10. The process according to claim 1, wherein the acidic montmorillonite adsorbent is characterized by having at least one NH.sub.3-TPD desorption peak with the size in the range from 9 to 60 ml/g at a high desorption region of a temperature in the range of 300 to 800 C.

11. The process according to claim 10, wherein the acidic montmorillonite adsorbent is an iron-containing montmorillonite.

12. The process according to claim 11, wherein the iron-containing montmorillonite has a Fe2O.sub.3 content in a range from 2 to 20 percent by weight with respect to the total weight of adsorbent.

13. The process according to claim 1, wherein the process further comprises, after contacting the hydrocarbon feedstock with the acidic montmorillonite adsorbent, a step of regenerating the acidic montmorillonite adsorbent.

14. The process according to claim 13, wherein the step of regenerating comprises contacting the acidic montmorillonite adsorbent with an inert gas at a temperature in the range from 100 to 400 C.

15. The process according to claim 14, wherein the inert gas is selected from nitrogen, helium, and argon.

Description

EXAMPLE

[0047] The following adsorbents were applied in the below examples;
Adsorbent A is a commercially available acid-treated montmorillonite adsorbent according to the invention.
Adsorbent B is an unmodified natural montmorillonite adsorbent (comparative example).
Adsorbent C is an unmodified natural acidic montmorillonite adsorbent according to the invention.
Adsorbent D is an acid treated montmorillonite adsorbent obtained by impregnation of 2 wt % of (NH.sub.4).sub.2SO.sub.4 over the Adsorbent C following by drying at 120 C. for 3 hours, according to the invention.

[0048] Characterization properties of each adsorbent are shown in the following Table 1.

TABLE-US-00001 TABLE 1 Characterization Property NH3-TPD Desorption NH3-TPD Desorption peak size at low temp. peak size at high temp. H+/g- Fe.sub.2O.sub.3 (below 300 C.) [ml/g at (below 300-800 C.) adsorbent content Adsorbent STP] [ml/g at STP] [mol] pH [% wt] A >43.1 <8.7 >500 3.3 1.56 B >15.7 <16.6 <1 0 1.6 C >14.6 >41.4 <1 0 12 D >30.2 >33.5 >50 4.3 7.3

Example 1

Removing Cyclopentene from Benzene

[0049] Each sample adsorbent was placed into the oven in order to remove trace of water at temperature 180 C. for overnight before testing.

[0050] The hydrocarbon feedstock used for testing was 150 ppm of cyclopentene in 0.05 of benzene.

[0051] Each adsorbent (previously dried) was added into the 25-mL of the hydrocarbon feedstock and was continuously stirred for 9 hours.

[0052] The resulting cyclopentene/benzene sample was then analyzed by Gas ChromatographyFlame Ionization Detector (GC-FID), which is a very co on analytical technique that is widely used in the petrochemical to see the amount of cyclopentene left in the benzene sample.

[0053] Results of adsorption test for Adsorbent A, B, C, d D are displayed in FIG. 1.

Example 2

[0054] The Adsorbent A, B, C, and D were tested for adsorption of nitrogen compound. The test was perform by packing 20 g of each adsorbent, previously dried at 180 C. in oven overnight, into separate cylinder vessels. The industrial benzene feedstock, con ng N-Formyl Morpholine (NFM) as a representative of a nitrogen compound, was then flowed pass each of the packed adsorbent at room temperature and ambient pressure. The inlet and outlet benzene concentration were analyzed by GC-FID.

[0055] Result of this test is shown in Table 2.

TABLE-US-00002 TABLE 2 Inlet NFM [ppb] Outlet NFM [ppb] Adsorbent A 1020 104 Adsorbent B 332 Adsorbent C 16 Adsorbent D Non detectable

[0056] From the result above, it can be seen that the inventive adsorbents can also be used for adsorbing a nitrogen compound, which is oftentimes found contaminated in benzene stream.

Example 3

Reduction of BI Value in Benzene

[0057] The Adsorbent D was used to test its efficiency in BI reduction in industrial benzene feedstock. 20 g of Adsorbent D, previously dried at 180 C. in an oven overnight, was pack into a cylinder vessel. The industrial benzene feedstock was then flowed pass the packed adsorbent at room temperature and ambient pressure. Inlet and outlet BI value of the industrial benzene were measured according to the standard method ASTM 5776-99. The inlet and outlet benzene concentration were analyzed by GC-FID. The test was repeated 3 times.

[0058] Results of this test are displayed in the following Table 2. It can be seen from the results that the Adsorbent D can efficiently reduce BI value in benzene feedstock to a very low level. Moreover, no loss of benzene was observed.

TABLE-US-00003 TABLE 3 1.sup.st Test 2.sup.nd Test 3.sup.rd Test Inlet Outlet Inlet Outlet Inlet Outlet Bromine Index 10.10 0.4 11.55 0.9 12.87 0.5 (BI) Value Benzene 99.9316 99.9532 99.9275 99.9536 99.9063 99.9268 (wt %)

[0059] The features described in the foregoing description and in the claims may, both separately and in any combination, be material for realizing the invention in diverse forms thereof.

Example 4

Reduction of BI Value in Linear Alkylbenzene (LAB)

[0060] The adsorbent A and C were used to test their efficiency in reduction of BI in linear alkylbenzene.

Feedstock containing linear alkylbenzene (a mixture of linear alkylbenzene with C10-C13 alkyl) and different BI contributors (alkene), i.e., cyclopentene, indene, and 1-undecene, were used.
The testing system was prepared by packing 5 grams of adsorbent in a cylinder vessel, the dry the adsorbent by heating it to 250 C. for 2 hours.
The testing were operated by passing the feedstock through the bed of adsorbent at room temperature (approximately 25-35 C.) and ambient pressure. Inlet and outlet BI values were measured according to the standard method ASTM D 5776-14a.
Test results are shown in Table 4.

TABLE-US-00004 TABLE 4 Outlet BI, Outlet BI, Aromatic treated by treated by Compound BI Contributors Inlet BI adsorbent A adsorbent C Linear Cyclopentene 8.0 0.5 2.0 alkylbenzene Indene 160.0 43.0 8.5 1-Undecene 8.0 2.0 0.5