US3385782A - Production of light hydrocarbon gases by hydrocracking high boiling hydrocarbons - Google Patents

Description

y 8, 1968 w. BUSS 3,385,782

PRODUCTION OF LIGHT HYDROCARBON GASES BY HYDROCRACKING HIGH BOILING HYDROCARBONS Filed May 6, 1966 COMPARISON CATALYST CURVE A Z 9 TOTAL 2 CONVERSOION TO 900 F. l.| J ,cuRvE E z 0 8 I /-CURVE F o 2 CURVE B 6 a: Pd ALUMINOSILICATE E CATALYST COMPARISON CATALYST 2o- I c4 -cuRvE c CU RVE o o l l 1 I I 760 no aoo 820 4540 see 680 TEMPERATURE INVENTOR WALDEEN C. BUSS TORNES United States Patent 3,385,782 PRODUCTION OF LIGHT HYDROCARBON GASES BY HYDRUCRACKIN G HIGH BOIL- ING HYDROCAONS Waldeen C. Buss, Richmond, Calif., assignor to Chevron Research Company, San Francisco, Calif., a corporation of Delaware Filed May 6, 1966, Ser. No. 548,258 1 Claim. (Cl. 208-111) ABSTRACT OF THE DISCLOSURE Hydrocracking hydrocarbon feeds boiling above 900 F. to produce light hydrocarbon gases, C -C in a yield of at least weight percent, using a Group VIII hydrogenating metal component associated with a crystalline zeolitic aluminosilicate.

The present invention relates to a process for the conversion of heavy hydrocarbon fractions to light hydrocarbon gases of one to four carbon atoms. More particularly, the present invention is concerned with the hydrocracking of hydrocarbon feeds, a substantial portion of which boils above 900 F., to light hydrocarbon gases of one to four carbon atoms, and especially three to four carbon atoms, the hydrocracking being accomplished in the presence of a catalyst comprising a zeolitic aluminosilicate and a hydrogenating metal component.

The light hydrocarbon gases of one to four carbon atoms have generally been synthesized as a by-product from the catalytic cracking and hydrocracking of hydrocarbon oils to obtain gasolines and higher boiling products. Although the light gases produced are usually only a few weight percent of the hydrocarbon feed cracked, they are very valuable, especially the gases containing three to four carbon atoms which are sold as liquefied petroleum gases or LPG for use as chemical raw materials and household fuels. Because of the increasing demand for light hydrocarbon gases, it would be valuable to have a process for producing light gases in higher yields than generally obtainable as a by-product in the production of gasoline. Moreover, since light hydrocarbon gases of one to four carbon atoms are generally produced at the expense of gasoline, it would be particularly valuable to have a process for hydrocracking high boiling feeds, which feeds are difficult to refine and hence are less valuable for gasoline production, directly to light hydrocarbon gases as a principal reaction product.

In accordance with the present invention, high boiling hydrocarbon feeds, at least a substantial portion of which boils above 900 F., can be converted directly to large quantities of light hydrocarbon gases of one to four carbon atoms as a principal reaction product by contacting said feed and hydrogen in a reaction Zone under hydrocracking conditions with a catalyst comprising a crystalline zeolitic aluminosilicate characterized by uniform pores of at least 6 A. and having a hydrogenating metal component intimately associated therewith, said contacting being at a relatively high temperature and at conditions sufficient to convert substantially all of said feed to products boiling below 900 F.

As illustrated hereinbelow, the present process is to be contrasted to prior hydrocracking processes which are mainly concerned with the production of high yields of gasoline and middle distillates and minimum production of light gases. The present process is particularly directed to obtaining high yields of light gases from high boiling petroleum feeds which are diflicult to convert to gasoline and other high quality fuel products.

The light gases produced, particularly the hydrocarbons 3,385,782 Patented May 28, 1968 ice of three to four atoms (C -C apart from being useful for LPG production, can be used in dehydrocyclodimerization reactions to produce higher molecular weight aromatic hydrocarbons.

The present invention may be understood and will be further explained with reference to the figure which is a graph comparing the conversion to light hydrocarbon gases as a function of hydrocracking temperature for a palladium containing zeolitic aluminosilicate catalyst and another catalyst.

Hydrocarbon feeds boiling above 900 F. are generally difiicult to convert to more useful lower boiling products. Hence it is considered a part of the present invention to use hydrocarbon feeds, a substantial amount of which boils above 900 F. and preferably hydrocarbon feeds at least of which boils above 900 F. It is understood, however, that the present invention may be used wherein less than 85% of the feed boils above 900 F. However, at least 50% of the feed should boil above 900 F. in order to realize the benefits of the present invention. Feedstocks which may be used in the hydrocracking process of the present invention include heavy virgin crudes, vacuum distillation residues, heavy catalytic cycle oils, and gas oils resulting from visbreaking of heavy oils. Particularly preferred feedstocks are solvent deasphalted oils, such as propane deasphalted oils, which boil in the desired temperature range. The hydrocarbon fractions may be derived from petroleum crude oils, shale oils, tar sand oils, coal hydrogenation or carbonization products and the like.

For purposes of the present hydrocracking process, it is not considered necessary to purify the hydrocarbon feeds of nitrogen and sulfur compounds. It has been found that the present invention works satisfactorily with feeds containing high nitrogen content, as, for example, feeds containing a nitrogen content above 5000 p.p.m. Thus it is a particular advantage of the present process that the hydrocarbon feeds do not require hydrofining operations, and in particular hydrodenitrification or hydrodesulfurization processes, prior to the hydrocracking step. It is understood, however, that hydrofining can be used in conjunction with the hydrocracking process if desired.

The crystalline zeolitic aluminosilicates encompassed by the present invention comprise open three-dimensional crystalline networks of alumina and silica tetrahedra, which tetrahedra are intimately connected with each other by the sharing of oxygen atoms. In the hydrated form the aluminosilicates can be represented by the basic formula:

wherein M is a cation which balances the negative electrovalence of the tetrahedra; n represents the valence of the cation; w, the moles of SiO and y, the moles of water. The cation, M, may be any of a number of ions, such as, for example, the alkali metal ions, and the alkaline earth ions. The cations may be mono-, di-, or trivalent. In general a particular type of crystalline zeolitic aluminosilicate will have values for w and y that fall in a definite range. The zeolitic cations, e.g. alkali metal or alkaline earth metal cations, may be replaced one with another by suitable exchange techniques. Consequently, crystalline zeolitic aluminosilicates are often employed as ion-exchange agents. The replacement of the zeolitic cations with other cations, .as, for example, the replacement of sodium cations with calcium cations, generally does not induce appreciable changes in the anionic framework.

The crystal structures of many zeolitic aluminosilicates exhibit interstices of molecular dimensions, which interstices are generally occupied by water of hydration. Dehydration results in a relatively open system of channels wherein foreign molecules may be adsorbed. Access to these channels is had by way of apertures in the crystal lattice, which effectively, then, limit the size and shape of molecules that can be adsorbed. Separation of mixtures of foreign molecules based on molecular dimensions is thus possible, and it is this characteristic property of many zeolitic aluminosilicates that has led to their designation as molecular sieves.

Both the natural and synthetic zeolitic aluminosilicates maybe used in the present invention. The aluminosilicates which find use for purposes of this invention possess relatively well-defined pore structures. The exact type of aluminosilicates is relatively unimportant as long as the pore structures comprise openings characterized by pore dimensions greater than 6 A., and in particular uniform pore diameters of between 6 and A. It is necessary that the uniform pore dimensions are larger than approximately 6 A. in order to permit the hydrocarbons to be hydrocracked to gain access to reactive sites of the catalyst. Generally, in order to obtain aluminosilicates of the necessary pore diameters the silica to alumina mole ratio in the crystalline form should be greater than about 2. Suitable zeolitic aluminosilicates which may be used in the present process are the natural faujasites; synthesized zeolite X which is described in US. Patent 2,882,244; and synthetized zeolite Y which is described in US. Patent 3,130,007. Zeolite Y is preferable because of its greater commercial availability and its greater stability.

The procedures for the preparation of synthetic crystalline zeolitic aluminosilicates are well known in the art. For example, these procedures generally involve the mixing and heating of a high silica/ alumina mole ratio mixture of sodium silicate and sodium aluminate. Thereagents are mixed under carefully controlled conditions to produce a crystalline product which contains sodium as the zeolitic cations. The sodium zeolitic cations can be subsequently ion-exchanged with other desirable cations.

The catalyst encompassed for use in the present process comprises a zeolitic aluminosilicate having intimately associated therewith a hydrogenating metal component. Suitable hydrogenating metal components for use in this invention are the metals, and compounds thereof, of Groups VI, VII, and VIII of the Periodic Table. However, the Group VIII hydrogenating metals, and compounds thereof, are preferred. The hydrogenating metal component can be in the form of elemental metal or its compounds, as, for example, the oxide or sulfide form. Although the oxides and sulfides are the preferred compound forms of the metal hydrogenating component, any compound which performs as a hydrogenating component may be used in the catalyst for purposes of this invention. The amount of hydrogenating metal component intimately associated with the zeolitic aluminosilicates can vary from 0.1 to weight percent calculated as the metal, but preferably will be in the range 0.5 to 10 weight percent. It is understood, of course, that mixtures of two or more metals or compounds may be intimately associated with the aluminosilicate.

The catalytically active hydrogenating metal component can be introduced into the crystalline aluminosilicate by any method which results in a highly dispersed catalytically active metal. Suitable methods which can be employed are impregnation and ion-exchange. Generally, in preparing the catalyst by impregnation, a zeolitic aluminosilicate is mixed with an aqueous solution of a decom-j posable metal compound, the metal compound being in an amount sufficient to contain the quantity of metal desired in the finally prepared catalyst product. The aluminosilicate is then dried and heated to a temperature sufficient to thoroughly remove the water. Further heating may be necessary to decompose the metal compound. Impregnation may also be accomplished by adsorption of a fluid decomposable compound of the metal, followed by decomposition of the metal compound. Ion-exchange can be satisfactorily accomplished by contacting the aluminosilicate with an aqueous solution of a suitable metal salt for sufiicient time to replace the zeolitic cations with the metal cations and then drying to remove water. Ionexchange may also occur with an aqueous solution containing a cationic metal complex followed by decomposition of the complex.

The metal component, whether incorporated into the crystal lattice by ion exchange or impregnation, can be chemically reduced to the elemental form by contact with a reducing atmosphere such as hydrogen. The reduced form of the metal can then be converted to an oxide or sulfide form, if desired, by contacting the metal containing aluminosilicate with, for example, an oxygen-containing or sulfur-containing atmosphere, respectively. Sulfiding is preferably performed by contacting the catalyst containing the hydrogenating metal component with a sulfur-containing hydrocarbon feed.

The zeolitic aluminosilicate containing a hydrogenating metal component can be mixed with other catalytic materials and used in the hydrocracking process of the present invention. For example, the aluminosilicate containing a hydrogenating metal component may be mixed with a silica-alumina type catalyst. Other suitable catalytic materials include silica-boria, silica-magnesia, and alumina. The crystalline zeolitic aluminosilicate containing a hydrogenating metal component can also be mixed with suitable support materials such as the clays to obtain beneficial property such as high attrition resistance and high compactibility. The physical form of the catalyst will vary with the manipulative process to which it may be exposed. Thus the present hydrocracking process can be carried out by maintaining the catalyst in a fluidized bed, in which case the catalyst will be in a powdered form; or, the present process can consist of a moving bed or fixed bed in which case the catalyst can be in the form of beads, tablets or extruded pellets.

The conditions of temperature, pressure, hydrogen fiow rate, and liquid hourly space velocity in the reactor are correlated to provide the degree of hydrocracking required to convert substantially all (i.e., above by weight, and, preferably above the feed boiling above 900 F. to products boiling below that temperature. Generally, the higher the boiling range of the feed, the higher the temperature, pressure and/or hydrogen flow rate necessary to convert the feed to products boiling below 900 F. Under properly selected conditions, light hydrocarbon gases can be produced as a principal reaction product, that is, preferably in a yield of at least 25 weight percent and more preferably 50 weight percent.

For the purposes of the present invention, the temperature is preferably maintained at least 10 F. above the minimum temperature at which the feed is substantially completely converted (i.e., above 90%) to products boiling below 900 F. In general, the temperature in the reaction zone for hydrocracking feedstocks in accordance with the present invention is at least 750 F., and more preferably at least 800 F. For higher boiling feedstocks, the hydrocracking temperature will in general be higher. Thus for feedstocks at least 85% of which boils above 900 F., the preferred temperature in the reaction zone is at least 800 F. and preferably at least 830 F. Ordinarily, it will not be necessary to go above a temperature of 950 F. Thus, substantially complete conversion of the feed to light hydrocarbon gases can generally be achieved at a temperature below 950 F. It is understood, however, that the temperature is only one of the hydrocracking conditions to control the yield of light gases produced.

The pressure advantageously influences the rate of hydrocracking as well as the extent of hydrocracking. Furthermore the pressure has the effect of influencing the catalyst activity and life, elevated pressures extending the life and activity of the catalyst. Generally, pressures between 1000 to 10,000 p.s.i.g. are used in the hydocracking process of the present invention, the higher pressures being used with the higher boiling feedstocks. Preferably, pressures between 2000-6000 p.s.i.g. are used.

The hydrogen flow rate into the reactor is maintained between approximately 1,000 to 20,000 s.c.f./bbl. of feed and preferably in the range 4,000 to 10,000 s.c.f./bbl. Generally, at least sufficient hydrogen is provided to supply that consumed in the cracking of high molecular weight hydrocarbons to light hydrocarbon gases and that consumed in the conversion of the nitrogen compounds to ammonia and any incidental hydrogenation of unsaturates and oxygen and sulfur compounds, while mai taining a significant hydrogen partial pressure. The hy-drogen consumption will generally vary from 1,000 to 10,000 s.c.f./bb1. of feed depending on the properties of the hydrocarbon feed and the other hydrocracking conditions used. Excess hydrogen is separated from the treated feed, and preferably purified and recycled. The use of more hydrogen than 20,000 s.c.f./bbl. of feed does not generally provide sufficient improvement to justify the increased cost of circulating it.

The liquid hourly space velocity (LHSV), that is, the flow of hydrocarbon feed relative to the catalyst, will generally be in the range 0.1-10 but preferably 0.3-5. The higher boiling the feed, the lower the space velocity. For example, a space velocity of 2 is advantageously used with a feed at least 50% of which boils above 900 F., while a space velocity of 0.5 is advantageously used with a feed at least 85% of which boils above 900 F.

The present invention may be more fully understood by reference to the following examples. In these examples since product distribution did not change appreciably after about one day of operation, the determinations of product distribution were made a-t any time after one day.

Example 1 A crystalline zeolitic aluminosilicate of the Y crystal type having intimately associated therewith a hydrogenat- 6 least about 85 of the feed boiled above 900 F. The principal characteristics of the feed were:

Gravity, API 16.2 Aniline point, F. 192.0 Total nitrogen content, p.p.m. 5950 Feed distillation range, wt. percent, R:

The high boiling hydrocarbon feed was contacted with the palladium containing aluminosilicate catalyst under hydrocracking conditions including a pressure of approximately 2400 p.s.i.g., a hydrogen flow rate into the reaction zone of approximately 6,000 s.c.f./bbl. of feed and a liquid hourly space velocity of 0.5. The hydrocracking process was conducted at various temperatures. The hydrocracking conditions and product distribution are presented in Table I. For comparison, a catalyst was selected as representative of the effect most conventional hydrocracking catalysts would have on light hydrocarbon gas production. This catalyst is very effective for converting heavy feeds to lower boiling products including gasoline and other middle distillate fuels. The comparison catalyst was composed of nickel and tungsten hydrogenating components associated with an active cracking support composed of mixed refractory oxides which were mainly alumina and silica; the catalyst did not contain any zeolitic aluminosilicate. Table I shows, for comparative purposes, the results obtained when the comparison catalyst was used for hydrocracking the propane deasphalted oil described above under conditions substantially the same as above. The amount of hydrogen not consumed in the hydrocracking process was measured and is recorded as hydrogen flow rate out.

TABLE I Reaction Conditions Product Distribution, Weight Percent Catalyst Temp, Press, H2 Rate F. p.s.i.g. LHSV Out, C1-C2 C3-C4 (ls-400 F. 400650 F. GET-900 I 900 F.+

s.e.f./bbl.

805 2,400 0 5 4,890 1.0 4.1 13.4 14.3 23.8 43 Palladium A1uminosilicate.. 830 2, 400 0.5 3. 7 11 21 9 855 2, 400 0. 5 2, 580 8. 2 46. 9 43 0. 6 1.0 0 Comparison Catalyst 805 2, 360 0.5 5, 280 1. 8 3. 2 29 35 23 8 850 2,460 0 5 3, 770 6.1 6.0 67 19 0 0 ing palladium component was prepared by contacting an ammonium aluminosilicate with an ammonium hydroxide solution containing palladium chloride, said palladium chloride being in suflicient quantity to permit 1.2% palladium to be deposited on the final catalyst preparation. The mixture was allowed to stand overnight, after which the excess solution was washed away with water. The ammonium aluminosilicate containing palladium was then dried at a temperature of 250 F. for sufficient time to remove most of the water and then calcined at 1000 F. The resulting hydrogen form of the sieve containing palladium as the hydrogenating metal component was treated at 1000 F. in a wet hydrogen atmosphere for a sufficient time toactivate the catalyst for hydrocracking reactions. The catalyst was then sulfided at 600 F. in a hydrogen and dimethyldisulfide atmosphere.

The deasphalted oil obtained by subjecting residuum from the vacuum distilling of petroleum crude to a propane deasphalting treatment, was used as the feedstock for the hydrocracking process using the above described palladium containing zeolitic .aluminosilicate catalyst. At

The percent conversion to light gaseous products containing one to four carbon atoms as well as the percent conversion to light gaseous products containing three to four carbon atoms at different hydrocracking temperatures for the two catalysts are presented in graphical form in the figure. The total hydrocracking conversion to products boiling below 900 F. (total conversion to 900 F.-) was measured as a function of hydrocracking temperature and is also presented in the figure.

Curves A and B in the figure illustrate that the comparison hydrocracking catalyst gave higher total conversion to products boiling below 900 F. than the zeolitic aluminosilicate catalyst at any particular temperature. Curves C and D indicate that the comparison hydrocracking catalyst gave a product of light hydrocarbon gases which increased only slightly as the hydrocracking temperature was increased above 800 F. It was heretofore considered that the effect of zeolitic aluminosilicates on the production of light gases would follow the same trend as the effect with the comparison catalyst and with most conventional hydrocracking catalysts; that is to say, that the production of light hydrocarbon gases in a hydrocracking process using a zeolitic aluminosilicate catalyst would increase only gradually as the hydrocracking temperature was increased. In contrast thereto the production of light hydrocarbon gases when using the zeolitic aluminosilicate catalyst in accordance with the present invention was significantly and dramatically increased, as shown by curves E and F in the figure. Thus by conducting the hydrocracking process with the above zeolitic aluminosilicate catalyst at a temperature and under conditions sufiicient to convert substantially all of the feed to products boiling below 900 F., light hydrocarbon gases can be produced as a principal reaction product. In this particular example, the feed was substantially completely converted (i.e., 90%) to products boiling below 900 F. at a temperature of about 830 F. and above this temperature the light hydrocarbon gas yield increased rapidly.

Referring now to Table I, it is noted that using a palladium-zeolitic aluminosilicate catalyst and under hydrocracking conditions, including a temperature of 855 F. whereby high gas yields were produced, that the remaining product consisted predominantly of gasoline. Thus a special benefit of the present process is that under conditions adapted to yield light gases as a principal reaction product, the remaining eflluent or product from the reactor will be exceptionally high in gasoline content. For example, when light hydrocarbon gases are produced in yields of about 50% by weight of the total product, the remaining product will comprise essentially gasoline.

Example 2 A nickel containing zeolitic aluminosilicate catalyst was prepared by exchanging approximately 6.3% nickel onto an ammonium aluminosilicate (type Y). The resulting catalyst, after proper drying and calcination treatment, was sulfided at 600 F. in a hydrogen and dimethyldisulfide atmosphere. The catalyst was used in a hydrocracking process employing a feed having the following principal characteristics:

Gravity, API 14.7 Aniline point, F. 166.0 Total nitrogen content, p.p.m. 8300 Feed distillation range, wt. percent, R:

The hydrocracking reaction conditions as well a the product distribution at two temperatures are given in Table II.

The results from hydrocracking of a high boiling feed with a nickel aluminosilicate catalyst are similar to the results obtained with the palladium aluminosilicate. The high gas yields produced at 850 F. were obtained above the temperature at which substantially all the feed was converted to products boiling below 900 F. It is apparent that rapid increase in gas yield was obtained in raising the temperature from 822 to 850 F.

Example 3 A catalyst comprising a zeolitic aluminosilicate of the Y crystal type and having intimately associated therewith 16% nickel, was used in the hydrocracking of the hydrocarbon feed described in Example 2. The catalyst was sulfided as in the previous examples prior to use. The product distribution and run conditions are presented in Table III. The hydrogen added to the reactor (H Rate In) and the hydrogen removed (H Rate Out), both measured in terms of standard cubic feet per barrel of feed are also presented in Table III. Exceptionally high gas yields were obtained. Note that the feed has been converted to products boiling below 900 F.

TABLE III Catalyst: Nickel aluminosilicate. Reaction conditions:

Temp, F. 850 Pressure, p.s.i.g 2350 LHSV 0.5 H rate in, s.f.c./bbl 6540 H rate out, s.c.f./bbl 2510 H consumed, s.c.f./bbl. 4030 Product distribution, wt. percent:

C -C 10.5 C -C 53.0 C -400 F. 34.0 400-650 F. 0 650-900 F. 0

EXAMPLE 4 Hydrocracking of the high boiling feed described in Example 2 was performed using a decationized zeolitic aluminosilicate containing no hydrogenating metal component. The reaction conditions and product distribution are shown in Table IV.

TABLE IV Catalyst: Decationized aluminosilicate. Reaction conditions:

Temp, F. 857 Pressure, p.s.i.g 2360 LHSV 0.5 H rate in, s.c.f./bbi 4900 H rate out, s.c.f./bbl 3540 H consumed, s.c.f./bbl. 1360 Product distribution, wt. percent:

C -C 8.7 C -C 10.3 C -400" F. 37.0 400-650 F. 30.0 650-900 F. 12.0 900 F.+ 1.2

Although the feed was substantially converted to products boiling below 900 F., the production of light gases (C -C was low. The yield of light hydrocarbon gases of one to four carbon atoms was considerably lower than yields obtained with an aluminosilicate catalyst containing a hydrogenating metal component. It is apparent that in order to obtain high yields of light hydrocarbon gases, the feed must be contacted, in the presence of hydrogen, with a catalyst comprising a zeolitic aluminosilicate and having intimately associated therewith a hydrogenating metal component.

The light hydrocarbon gases produced by the process of the present invention can be subsequently subjected to steam reforming or partial oxidation to produce a hydrogen-rich or methane-rich product for use as an ingredient in fuel gas, e.g., town gas. Because town gas comprises, predominantly, hydrogen, and a hydrocarbon or mixture of hydrocarbons (mainly methane or methane and ethane), it is contemplated that the light hydrocarbons produced in the present process can be separated into two fractions, a first fraction comprising essentially the hydrocarbons of one to two carbon atoms, and a second fraction com-prising the hydrocarbons of three to four carbon atoms; then using said first fraction as an ingredient of town ga and subjecting said second fraction to steam reforming or partial oxidation for conversion to hydrogen and/or methane. Alternatively, the entire light hydrocarbon gases can be used as a fuel gas enrichment material for a hydrogen-rich gas produced in a steam reforming process or other suitable gasification process.

The gasoline produced along with the light hydrocarbon gases can also be subjected to various gasification processes, e.g., steam reforming, thermal hydrocracking, or partial oxidation, to yield a hydrogen-rich or methanerich gas for use as a fuel gas. Generally, however, the gasoline fraction, which has been found to be highly aromatic, will be used as a motor fuel.

I claim:

1. A process for the conversion of a heavy hydrocarbon feed, at least 85 weight percent of which boils above 900 F., to light hydrocarbon gases of l to 4 carbon atoms in a yield of at least 25 Weight percent as a principal reaction product Which comprises contacting said feed and hydrogen in a reaction zone With a catalyst comprising a crystalline zeolitic aluminosilicate of the Y crystal type characterized by uniform pores from 6 to 15 Angstroms and having intimately associated therewith a Group VIII hydrogenating metal component, at hydrocracking conditions including a temperature above about 830 F., a pressure between about 2000 to 6000 p.s.i.g., and a liquid hourly space velocity of from 0.1 to 10, converting above 90 weight percent of the feed per pass to products boiling below 900 F., and recovering said light hydrocarbon gases.

References Cited UNITED STATES PATENTS ABRAHAM RIMENS, Primary Examiner.

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