|Title of Invention||
"A NEW PROCESS FOR PREPARATION OF 100 LL AVIATION GASOLINE"
|Abstract||sA new process for the preparation of 100 LL aviation gasoline by passing the dimefraction of oligomerised isobutylene and hydrogen through a reactor loaded with Pt-Sn catalysts supported on alumina at a temperature of 200 to 350°C, pressure of 20-60 kg/cm2 and space velocity of 1-5 hr, followed by blending of resultant hydrogenated product with 20% toluene and 4% benzene to get 100 LL (100 octane low lead) aviation gasoline.|
|Full Text||This invention relates to a new process for the preparation of 100 LL aviation gasoline.
This invention particularly relates to new process for preparation of 100 LL ( 100 octane low lead) aviation gasoline by hydrogenating the by product of oligomerised isobutylene as a blending stock. This invention particularly relates to the preparation of high octane type of compounds required in formulation of 100 LL aviation gasoline. The high octane hydrocarbons prepared by the process of this invention falls in the gasoline range. More specifically, the present invention relates to new approach for the preparation of isoparaffins hydrocarbons of carbon chainC4, C5, C6, C7 and C8 range. They are produced by hydrogenating the byproduct of oligomerised isobutylene such as Dimer over Pt-Sn on alumina used as a hydrogenation catalyst.
Large varieties of petroleum feedstocks, such as reformate, naphtha, alkylates, isopentane and natural gas condensate etc are being used as blending stocks to constitute 100 LL aviation gasoline. These components have high research and motor octane numbers and, hence, are responsible for maintaining the high octane number required in formulation of 100 LL aviation gasoline i.e. minimum motor octane number 99.5. It is well known that straight chain normal paraffins have low octane numbers, whereas aromatics have high octane numbers. Isoparaffins and naphthenes octane number falls between the two. 100 LL aviation gasoline is required to have aromatics restricted to about 25% vol only. Isoparaffins particularly of C7-C8 range having high research octane number (RON) and Motor octane number (MON) are main constituents in 100 LL aviation gasoline to the extent of 60-70%.
There are reports in the literature that for producing 100 LL aviation gasoline, alkylates are the main components. These alkylates are produced mainly by alkylation of iso paraffins such as isobutane with mono olefins (propylene, butylenes and amylenes). The alkylation is catalysed by protinic acids viz. sulphuric acid, hydrogen fluoride and by Friedel Crafts type halide catalysts viz. aluminium chloride, boron floride, zirconium chloride and others.
Sulphuric acid (H2SO4) and hydrogen fluoride (HF) are the preferred catalysts for alkylation in petroleum refining industry because of the selectivity of the reactions and the control of the catalytic activity etc. However, these are not eco-friendly due to their handling and various other problems like sludge disposal etc. These alkylates which contains C7-C9 branched paraffins mainly iso octane (2, 2,4 tri methyl pentane) as a principal component and are being used all over the world. All these above processes use isobutene as one of the component for producing the alkylates. Use of these organic compounds results in limitations of availability of alkylates in the world market. Therefore, there are number of limitations in obtaining alkylates required in blending 100 LL aviation gasoline. These limitations are :
1. Isobutane which is very expensive is used as feedstock for producing alkylates.
2. The availability of iso-butane being pure component is rather limited
3. The availability of alkylates is getting limited due to conventional catalyst
(H2SO4/HF) used in manufacturing it. The process is not eco-friendly but
The main object of the present invention is to provide a new process for the preparation of 100 LL aviation gasoline by hydrogenating the byproduct of oligomerized isobutylene. The hydrogenated product is highly suitable to be used as a main blending stock in its formulation. Since the feed is a byproduct and don't find any suitable outlet and therefore, is quite cheap and readily available source.
Accordingly, the present invention provides a new process for the preparation of 100 LL aviation gasoline which comprises passing the dimefraction of oligomerised isobutylene and hydrogen through a reactor loaded with Pt-Sn catalysts supported on alumina at a temperature of 200 to 350°C, pressure of 20-60 kg/cm2 and space velocity of 1-5 hr, followed by blending of resultant hydrogenated product with 20% toluene and 4% benzene to get 100 LL (100 octane low lead) aviation gasoline.
According to embodiment of the invention the hydrogenation reaction is carried out preferably at a temperature of 230 to 290°C, space velocity of 1.5 to 2.5 h-1and pressure of 30-40 kg/cm2 in the presence of catalyst. The suitable cut of the dimer/trimer refers to IBP-120°C or IBP-140°C cut.
The invention is further illustrated in the following examples which should not be construed to limit the scope of this invention. Example-1
The example describes the process for the preparation of isoparaffins using the catalyst having Pt-Sn over high purity AI2O3 support. About 70ml of the catalyst having from 0.1-1.0wt%Pt and 0.1-1.0 wt% Sn on acidic alumina support is loaded in a fixed
bed continuous down flow high pressure, high temperature catalytic reactor. Reaction feed by-product of oligomerised isobutylene, mainly Dimer fraction obtained after distillation up to 120 to 140°C, was passed through the catalyst bed. Hydrogen was used for hydrogenating the reaction feed. The gas present in the system was recycled at the rate of 200 lit/hr. The product analysis is presented in Table-1.
Operating Conditions: Reactor Temperature, °C 290, Pressure, Kg/cm2 35
Olefins Hydrogenated; 100%
This example described the effect of reaction temperature on selectivity with Dimer feed. The same catalyst has been used as given in Example-1. The results are illustrated in Table-2.
Effect of Reaction Temperature on Selectivity Feed = Dimer
This example (Table-3) includes the results of hydrogenation on change point of the feed stock. The catalyst is the same as explained in Examples 1 & 2.
Effect of Feed Stock Boiling Point on Hydrogenation Recycle Gas = 200 lit/hr
This example (Table-4) illustrates the results of the catalyst ageing characteristics with time on stream. The catalyst is the same as explained in Examples 1,2 & 3.
Effect of Time on Product Quality
Feed = Dimer
WHSV = 2 hr'1
The example (Table-5) shows that hydrogenated Dimer as shown in Example-1 after blending required amount of aromatics meets the specification DERD-2485 required for 100 LL aviation gasoline.
Specific Properties of Formulated 100 LL Aviation Gasoline vis a vis DERD-2485 Specifications
The main advantages of the new approach of the present invention are :
(i) Less economically viable feedstock being the by-product of oligomerised
polyisobutylene can be converted into highly valuable product which can be used
as main blending component for 100 LL aviation gasoline, (ii) Feedstock is highly noxious but after hydrogenation given 100% clean, olefin free
hydrogenated product and no foul smell, (iii) The catalyst used for the process has long life, (iv) the process produces a rich concentration of high degree of branch chain paraffins
(iso paraffins) of C4-C9range.
(v) High degree of flexibility of operation in blending for production of 100 LL
aviation gasoline, (vi) Process and products are eco-friendly and does not produce any disposal problem
and, therefore, pollutants free.
1. A new process for the preparation of 100 LL aviation gasoline which
comprises passing the dimefraction of oligomerised isobutylene and
hydrogen through a reactor loaded with Pt-Sn catalysts supported on
alumina at a temperature of 200 to 350°C, pressure of 20-60 kg/cm2 and
space velocity of 1-5 hr, followed by blending of resultant hydrogenated
product with 20% toluene and 4% benzene to get 100 LL (100 octane low
lead) aviation gasoline.
2. A process as claimed in claim 1 wherein the space velocity used ranges from
1.5 to 2.5 h-1.
3. A process as claimed in claim 1 & 2 wherein the reaction is carried at a
temperature of 230 to 290°C
4. A process for the preparation of 100 LL aviation gasoline substantially as
herein described with reference to the examples.
|Indian Patent Application Number||242/DEL/2000|
|PG Journal Number||13/2009|
|Date of Filing||16-Mar-2000|
|Name of Patentee||COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH|
|Applicant Address||RAFI MARG, NEW DELHI-110001, INDIA.|
|PCT International Classification Number||C10L 1/02|
|PCT International Application Number||N/A|
|PCT International Filing date|