FORM 2 THE PATENTS ACT 1970
(39 of 1970)
AND
PATENT RULES
PROVISIONAL SPECIFICATION
(See Section 10 rule 13)


TITLE OF THE INVENTION PRETREATMENT OF HEAVY PETRO-BOTTOM STOCKS AND COAL TAR
APPLICANT PRADEEP METALS LTD-
(A Company Incorporated under the Companies Act. 1956)
R - 205, TTC Industrial Area
M.I.D.C., Rabale,
Maharashtra, India.

29 JUL 2008
The following specification describes the invention :


INTRODUCTION
This invention relates to the processing of heavy petro-bottom stocks and/or coal tar foe enhancement of quantum and quality of middle distillates.
This invention particularly relates to the pretreatment of heavy petro-bottom stocks like HVGO (Heavy Vacuum Gas Oil) or coal tar.
This invention more particularly relates to the pretreatment of heavy petro-bottom stocks like HVGO (Heavy Vacuum Gas Oil) or coal tar comprising
a) Magnetising the HVGO or coal tar;
b) Exposing such magnetised material from stage (a) mentioned above, to electromagnetic radiations such as Microwave
c) With or without addition of activators in trace
BACKGROUND & PRIOR ART
In the present context of high cost and limited resources of crude oil added to the drain of foreign exchange reserves due to the import of crude oil, every attempt should be made to save petroleum stocks efficiently for maximizing the products and in particular, the middle distillates. Middle distillates account for 60% of product demand and the share is projected to increase to over 68% of the total demand of 100 million tons by 2010. Therefore, any technique which will enhance the yield of the middle distillates from petro-heavy stocks such as vacuum distillate residues (HVGO) etc., with less energy consumption, should go a long way in meeting the country's rapid demand in energy requirements.
New crude supplies are more challenging to process. Global demand is growing with changing fuel specifications, escalating costs and competition for resources. This makes the need to conserve energy - to make every molecule count. Countries like India must respond in new, innovative ways. And it will take strategic thinking, new technology, and most importantly, human ingenuity to meet the world's energy needs in this century.
Heavy Vacuum Gas Oil is the 'residual' in the distillation unit that has distilled crude oil. It is generally obtained from the residue of vacuum distillation using reduced pressures (25 -100 mm Hg) to avoid thermal cracking. It also includes the residue of the atmospheric distillation unit. The boiling range is approximately 260° to 600° C. at one atmosphere
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pressure. The density is approximately 0.97 g/ml. The aromatic content can be greater than 50% and the sulfur content can be as high as 3.5 wt %. HVGO if treated properly can be an important source of middle distillates and the prior art describes various methods of obtaining such middle distillates. The aim of our invention is to improve the yield and quality of these middle distillates obtained from HVGO, than is currently obtained.
Coal tar is a product obtained during the low-temperature / high-temperature carbonization (LTC / HTC) of coal/coking coal. This tar on hydrocracking yields middle distillates (consisting of kerosene and diesel) of the same quality as the one obtained from petroleum fractions such as HVGO. It is known that LTC tar is more enriched with respect to middle distillate constituents as compared to HTC tar.
HVGO is presently hydro-desulfurized and cracked in a once-through hydrocracker (OHCU) or /and in a Fluid Catalytic Cracking Unit (FCCU) in order to obtain the middle distillates.
In a typical hydrocracking process, the petroleum feedstock is brought into contact with a catalyst at temperature in the range of about 250° C. to about 430° C, hydrogen pressure in the range of about 200 to about 2000 psi, and space velocity in the range of about 0.5 to about 2.5 h-1.
Many refineries hydro-treat virgin and cracked feed-stocks in order to obtain upgraded gasoline and diesel products. These refineries utilize high-pressure units. High pressure hydro-desulphurization (HDS) units are used with cracked vacuum gas oil (VGO), and when operated between 700-1200 psig, can achieve HDS conversion rates of greater than 99% so as provide a product having a sulphur content between 0.002 and 0.12% wt. This product is then fed to a fluid catalytic cracking (FCC) process to produce gasoline and Diesel fuel with sulfur content less than 150 ppm and 600 ppm respectively.
There are various patents that teach the method of such hydrocracking of Heavy Vacuum Gas Oil. viz. EP0613937 which teaches a process for the fluid catalytic cracking of heavy fraction oils. US3617526 teaches hydrodesulfurization of a vacuum gas oil and vacuum residuum. CA2116514 explains process for the fluid catalytic cracking of heavy fraction oils. A paper by Miron V. Landau, Leonid Vradman and others, describes Hydrocracking of Heavy Vacuum Gas Oil with a Pt/H-beta-A12O3 Catalyst & Effect of Zeolite Crystal Size in the Nanoscale Range.
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However certain limitations in the above mentioned process can be seen with respect to the high costs of effective catalysts to be used, the high pressure and temperature required for the present operating conditions. Various attempts have been made that would lower the process parameters, while increasing the yield and quality, but the progress made thus far is mostly small improvements over existing catalyst systems.
We have now set our objective to investigate alterative processing to improve the yield of the middle distillates obtained from HVGO or coal tar and to improve the quality of the middle distillates obtained from HVGO.
We have now interestingly found that the quality and quantity of the middle distillates can be improved by the pre-treatment of heavy petro-bottom stocks like HVGO or coal tar, with our invented process comprising
a) Magnetising the HVGO or coal tar;
b) Exposing such magnetised material from stage (a) mentioned above, to electromagnetic radiations such as Microwave
Accordingly this invention relates to the pre-treatment of Heavy petro-bottom stocks in a custom designed magnetizer and then subjecting such treated HVGO or coal tar to microwave energy under a controlled atmosphere in a custom designed microwave unit and then subjecting it to otherwise normal procedure of hydrocracking.
The invention requires receiving HVGO (from refineries) for processing, and exposing it to magnetisation, and then electromagnetic radiations and obtaining a triggering effect of the combination thereof under controlled conditions. After processing this treated HVGO was passed through the conventional hydrodesulphurization/hydro-cracking, and then on determining the yield and the respective properties of middle distillates, viz. diesel and kerosene fractions, appreciable enhancement can be obtained then by otherwise conventional hydrocracking.
The above invention can be carried out with or without the 'activators' in trace. Activators are selected from trace elements usually present in the HVGO or coal tar. They are generally but not limited to magnetisable materials or microwave enhancing minerals or suphur related compounds that help enhance the object of the invention sought.
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The invention uses a specially designed magnetic system and electromagnetic treatment system that can be included even in the existing hydrocracking unit design and layout. The invention comprises of exposing the feed at the optimized power levels and duration of magnetization and electromagnetic radiations, and thereby leading to an enhanced effect in addition to its mere combination. That results in the HVGO and middle distillates having improved (desired) fuel fractions and properties.
The invention relates to maximizing the production and enhancement of the quality of products, in particular, the middle distillates at less severe operating conditions of temperature and pressure including the duration in the hydro-cracker unit. This enables operation of Hydrocracker Unit at the lower temperatures and pressures and correspondingly saving in energy and also enhancing the throughput. Enhancement in the yield of Middle distillates with increase in Cetane Number and smoke point, Reduced Pour Point and Viscosity of middle distillate products is seen as a result of this invention. The reduction in sulphur in the products is another achievement of this invention thereby reducing the pollutants and saving of environment.
DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION
Procedure: Conventionally HVGO from VDU (Vacuum Distillation Unit) + ADU (Atmospheric Distillation Unit) is sent to OHCU (Once-through Hydrocracker Unit) and thence to FCCU (Fluid Catalytic Cracking Unit) . In the invented process, HVGO from VDU + ADU is sent through a magnetizer followed by microwave treatment unit and then to OHCU and thence to FCCU.

It is seen that there is a qualitative as well as a quantitative increase in the yield of middle distillates.
EXAMPLES
The invention is illustrated with the help of the following experimental example and figures . This example is for illustration only and not for restricting the scope of invention.
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For the purpose of arriving at the optimum magnetization intensity and duration for microwave treatment, for the sake of experiment, HVGO, prior to the actual experiment was subjected to magnetic intensities of less than 10K gauss, and then also subjected to microwave treatments of various durations and types upto 3 mins. Such treated HVGO then showed qualitative and quantitative enhancements as compared to the untreated one. This is evident from the various readings that were taken while analysing the effects of the above mentioned treatment on HVGO at various temperatures and intensities, prior to further hydrocracking etc. However it was the object of the invention experiment to analyse the effect of such treatments on the distilled products obtained after hydrocracking Hence, not limiting the experiments to such findings, from the readings it was decided to have 6 K gauss intensity of magnetization and microwave treatment of 2 mins. during the experiment.
Example I
5 Liters of Mathura refinery HVGO sample was obtained and was magnetized at various magnetic intensities. For the invention and experimentation, an electro magnet with the possibility of magnetic field control was designed and employed [See Fig. I]. The magnetic field intensity during sample run was maintained at 6 K gauss. HVGO sample along with the wax content was allowed to flow through the glass tube of volume around 150 ml. The glass tube was fitted with the stoppers at the both ends with which the flow rate of HVGO during magnetization was controlled. The flow rate of around 30 ml/min was maintained. The residence time in the magnetic field was maintained at 6 min. The sample so treated was collected till a volume of 5 L. was collected.
Then the so treated sample was subjected to electromagnetic radiations. The microwave system installed with 2 magnetrons of 1.25 KW power magnetron working at 2.45 GHz frequency was used during the invention experimentation [See Fig. II]. The magnetically treated HVGO sample of around 5 L was treated batch wise in a microwave field. The HVGO sample was collected in a glass container and placed in the microwave system. The chamber was flushed with inert gas such as high purity nitrogen. The samples were exposed for different time duration at above mentioned microwave input power and were analysed for quality improvements.
The magnetized & Microwave treated HVGO was hydrodesulphurised/ hydrocracked in a conventional hydrocracker after pre-heating sample and removing wax. During hydro¬cracking, catalyst used was Ni-Mo based around 60 g. The hydrocracking was done under
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hydrogen atmosphere. The flow of hydrogen was maintained typically at around 4-51/h pressure. The yield & quality of middle distillates was then determined as per the practice (Kerosene fractions: 150 °- 250 °C & Diesel fractions: 250 ° - 370 °C temperature range)
For hydrodesulphurization / hydrocracking the reactor was flushed with hydrogen to the desired pressure. Reaction was allowed to continue for 2 hours after attaining desired temperature and pressure. The reactor was then cooled and gases were vented off slowly so that no liquid product is left along with gases. Liquid product was filtered and sent to distillation unit for obtaining the yield of middle distillates.
The outlet product from the reactor was taken into a 5 litre capacity distillation flask. The contents in the flask were heated slowly and temperatures noted when the first drop of condensate was collected at Initial Boiling Point (IBP). Distillation was continued up to 250°C at normal pressure. Further distillation was done under vacuum the temperature and pressure were varied up to 280 C and 20 mm Hg. Vacuum was applied to minimize the energy consumption and to avoid thermal cracking. The cracked samples were collected and analysed for API gravity (see Fig. III).
The same was further distilled and at regular intervals percentage volume distilled and corresponding temperatures were noted. A plot was between percentage volume distilled and temperature which is called True Boiling Point (TBP) curve. From this plot the yield of distillates could be obtained directly. Then, the various fractions received were tested for different qualities viz. kerosene fractions tested for API gravity (see Fig. IV) and smoke point (see Fig. VIII). And Diesel fraction tested for API Gravity (see Fig. V), flash point (see Fig. VI), Aniline point (see Fig. VII) and Diesel Index (see Fig. IX)
Fig. X shows the effect of the Magnetic treatment and Microwave Treatment on yield of middle distillates from HVGO at various temperatures.
The various observations are given herewith.
Fig. Ill and Table III A shows the effect of Magnetisation cum Microwave treatment on the API Gravity of HVGO prior to True Boiling Point distillation. Fig IV and Table IV A shows the effect of Magnetisation cum Microwave treatment on the API Gravity of Distillates from 140°C - 250 °C (Kerosene)
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Fig V and Table V A shows the effect of Magnetisation cum Microwave treatment on
the API Gravity of Distillates from 250°C -370°C (Diesel)
Fig VI and Table VI A shows the effect of Magnetisation cum Microwave treatment
on the Flash Point of Distillates from 250°C -370°C (Diesel)
Fig VII and Table VII A shows the effect of Magnetisation cum Microwave treatment
on the Aniline Point of Distillates from 250°C - 370 °C (Diesel)
Fig VIII and Table VIII A shows the effect of Magnetisation cum Microwave
treatment on the Smoke Point of Distillates from 140°C - 250 C (Kerosene)
Fig IX and Table IX A shows the effect of Magnetisation cum Microwave treatment
on the Diesel Index of Distillates from 250°C - 370 °C (Diesel)
Fig X and Table X A shows the effect of Magnetisation cum Microwave treatment on
the yield of Middle Distillates.
Thus, one embodiment of the invention shows, that when as a part of the invention, the HVGO is first magnetized in the magnetic intensity range of 6 K Gauss for a duration of 6 mins., and this magnetized stream is further subjected to electromagnetic radiations in the frequency of 2.45 GHz at power levels of 2.5 KW for 2 mins., before being hydrocracked, and then hydrocracked but at a pressure reduced from around 2060 psig to 1760 psig , at a temperature reduced from around 450 deg. C to 425 deg.C, there is quantitative increase in the yields of the middle distillates esp. Kerosene and Gasoline by around 11% etc.
The improvement in the quality of the products can be seen as including an increase of Aniline point in the case of diesel, an increase in Diesel index, an increase in smoke point of kerosene etc.
Dated this 29th day of July, 2008
For, Pradeep Metals Ltd.

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