Process and a system for enhancing liquid yield of heavy hydrocarbon feedstock

Abstract

The present invention provides a process and a system for coking and simultaneous upgrading of a heavy hydrocarbon feedstock. More particularly the present invention relates to a process of cracking heavy hydrocarbon feedstock employing high heat carrier, incorporated with weak acid sites for improving the liquid yield and reducing coke yield. The feedstock is vaporized and brought in contact with a heat carrier material to produce a product stream and separating the product stream from the particulate heat carrier, regeneration of the particulate heat carrier to the extent of 10-30% and collecting a gaseous and liquid product from the product stream.

Claims

1. A process for coking and simultaneous upgrading of a heavy hydrocarbon feedstock, comprising: a. providing a heated particulate material to a reactor chamber; b. dispensing preheated heavy hydrocarbon feedstock in the reactor chamber such that the same comes in contact with the particulate material at a temperature in the range of 480 C. to 620 C.; c. allowing said heavy hydrocarbon feedstock to stay in contact with the particulate material for a predetermined time period to form a product mixture and a coke laden particulate material; d. withdrawing the product mixture from the reactor chamber; and e. regenerating 10 to 30 wt % of the coke laden particulate material and recirculating the regenerated particulate material with reduced velocity using a first cyclone device and a second cyclone device to the reactor chamber, wherein the first and the second cyclone device are the same; wherein: the preheated heavy hydrocarbon feedstock is dispensed as an atomized spray in the reactor chamber; the predetermined time period is such that the product comprises about 70 wt % to about 80 wt % of hydrocarbons having boiling point in the range of about 40 to 600 C.; and the particulate material has specific area in the range of 100 to 200 m.sup.2/gm; Heat capacity in the range of 0.9 to 1.0 KJ/Kg C.; acidity of more than mass equivalent per gram and apparent bulk density of 0.7 to 1.0 gm/cc.

2. The process as claimed in claim 1, wherein the particulate material comprises a modified clay component, a binder component and optionally a diluent material, wherein the binder has less than 0.1 wt % of soda.

3. The process as claimed in claim 2, wherein the modified clay is selected from modified kaolinite, modified bentonite, modified illite, modified vermiculite, modified smectite, modified montmorillonite, modified sepiolite, modified hectorite and mixtures thereof.

4. The process as claimed in claim 2, wherein the binder is selected from the group comprising of alumina and the alumina is selected from alumina gel, psedobohemite, aluminium trihydrate, eta, theta and gamma.

5. The process as claimed in claim 2, wherein the diluent material is selected from non-modified clay, silica and aluminium trihydrate.

6. The process as claimed in claim 1, wherein the predetermined time period is in excess of about 60 seconds.

7. The process as claimed in claim 1, wherein the predetermined time period is maintained in the range of about 60 to about 900 seconds.

8. The process as claimed in claim 1, wherein the predetermined time period is maintained in the range of about 60 to about 600 seconds.

9. The process as claimed in claim 1, wherein the predetermined time period is maintained in the range of about 60 to about 300 seconds.

10. The process as claimed in claim 1, wherein a temperature during the predetermined period is maintained in the range of about 480 C. to 590 C.

11. The process as claimed in claim 1, wherein an amount of preheated heavy hydrocarbon feedstock provided to the reactor chamber is such that a loading ratio of said heated particulate material to said preheated heavy hydrocarbon feedstock is in the range of 4:1 to 20:1.

12. The process as claimed in claim 1, wherein the heavy hydrocarbon feedstock has a CCR content in excess of about 20 wt %.

13. The process as claimed in claim 1, wherein the heavy hydrocarbon feedstock is selected from the group comprising of heavy oil, bitumen or mixtures thereof.

14. The process as claimed in claim 1, further comprising separating the product mixture to obtain a light fraction and a heavy fraction and optionally recirculating at least a part of the heavy fraction to the reactor chamber.

15. The process as claimed in claim 14, wherein the step of separating the product mixture to obtain a light fraction and a heavy fraction is performed in a condenser.

16. The process as claimed in claim 1, further comprising controlling a velocity of the coke laden particulate material and/or controlling a velocity of regenerated particulate material.

17. The process as claimed in claim 1, wherein the reactor chamber is in the form of an upflow reactor.

18. The process as claimed in claim 1, wherein the step of providing a particulate material to the reactor chamber comprises maintaining the particulate material in form of a fluidized bed in the reactor chamber.

19. The process as claimed in claim 18, wherein maintaining the particulate material in form of a fluidized bed in the reactor chamber comprises feeding a fluidizing medium via at least one inlet located at a first elevation of the reactor chamber and feeding the particulate material via at least one inlet located at a second elevation of the reactor chamber.

20. The process as claimed in claim 1, wherein the step of dispensing preheated heavy hydrocarbon feedstock in the reactor chamber comprises dispensing the heavy hydrocarbon feedstock as an atomized spray from at least a top end of the reactor chamber.

21. The process as claimed in claim 1, wherein the step of dispensing preheated heavy hydrocarbon feedstock in the reactor chamber comprises dispensing the heavy hydrocarbon feedstock as an atomized spray from a plurality of elevations within the reactor chamber.

22. The process as claimed in claim 1, wherein the step of allowing said heavy hydrocarbon feedstock to contact with the particulate material to form a product mixture and a coke laden particulate material comprises maintaining the heavy hydrocarbon feedstock and the particulate material in a conversion zone of the reactor chamber.

Description

BRIEF DESCRIPTION OF DRAWING

(1) FIG. 1 illustrates process apparatus of the invention.

(2) FIG. 2 illustrates graph of coke yield, wt % with respect to % of coke burnt.

(3) The above and other aspects of the present invention are further attained and supported by the following embodiments described herein. However, the described embodiments are in accordance with the best mode of practice and the scope of the invention is not restricted to the described embodiments herein after.

DETAILED DESCRIPTION OF INVENTION

(4) While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the scope of the invention as defined by the appended claims.

(5) The present invention relates in o process of cracking heavy hydrocarbon feedstock employing high heat carrier, incorporated with weak acid sites for improving the liquid yield and reducing coke yield. More specifically, this invention relates to the use of coking process in order to enhance the liquid yield whenever heavier feed stocks i.e feed containing high CCR (Conradson Carbon Residue), Metals such as Nickel, vanadium and Asphaltenes are to be processed. The process employs upgrading heavy feedstock to valuable liquid products with increase in Total Cycle Oil (TCO) yield and reduction in CLO Clarified Oil (CU)) yield.

(6) Accordingly, the present invention provides a process for coking and simultaneous upgrading of a heavy hydrocarbon feedstock, comprising:

(7) (a) providing a heated particulate material to a reactor chamber;

(8) (b) dispensing preheated heavy hydrocarbon feedstock in the reactor chamber such that the same comes in contact with the particulate material at a temperature in the range of 480 C. to 620 C.;

(9) (c) allowing said heavy hydrocarbon feedstock to stay in contact with t .e particulate material for a predetermined time period to form a product mixture and a coke laden particulate material; and

(10) (d) withdrawing the product mixture from the reactor chamber;

(11) characterized in that: the preheated heavy hydrocarbon feedstock is dispensed as an atomized spray in the reactor chamber; the predetermined time period is such that the product comprises about 70 wt % to about 80 wt % of hydrocarbons having boiling point in the range of about 40 to 600 C.

(12) In one embodiment of the present invention, the particulate material has specific area in the range of 100 to 200 m.sup.2/gm; Heat capacity in the range of 0.9 to 1.0 KJ/Kg C.; acidity of more than mass equivalent per gram and apparent bulk density (ABD) of 0.7 to 1.0 gm/cc.

(13) More particularly, the catalyst for cracking heavy hydrocarbons comprises a clay material, silica alumina binder and matrix, wherein the catalyst is having surface area between 100-200 m.sup.2/gm, heat capacity 0.9-1, ABD of 0.7 to 1 g/cc, acidity of 0.35 meq/gm.

(14) In an embodiment of the present invention, the particulate material comprises a modified clay component, a binder component and optionally a diluent material, wherein the binder has less than 0.1 wt % of soda.

(15) In another embodiment of the present invention, the modified clay is selected from modified kaolinite, modified bentonite, modified illite, modified vermiculite, modified smectite, modified montmorillonite, modified sepiolite, modified hectorite and mixtures thereof.

(16) In yet another embodiment of the present invention, the binder is selected from the group comprising of alumina and the alumina is selected from alumina gel, psedobohemite, aluminium trihydrate, eta, theta and gamma.

(17) In still another embodiment of the present invention, the diluent material is selected from non-modified clay, silica, and aluminium trihydrate.

(18) In yet another embodiment of the present invention, the predetermined time period is in excess of about 60 seconds.

(19) In still another embodiment of the present invention, the predetermined time period is maintained in the range of about 60 to about 900 seconds.

(20) In yet another embodiment of the present invention, the predetermined time period is maintained in the range of about 60 to about 600 seconds.

(21) In still another embodiment of the present invention, the predetermined time period is maintained in the range of about 60 to about 300 seconds.

(22) In another embodiment of the present invention, a temperature during the predetermined period is maintained in the range of about 480 C., to 590 C.

(23) In yet another embodiment of the present invention, an amount of preheated heavy hydrocarbon feedstock provided to the reactor chamber is such that a loading ratio of said heated particulate material to said preheated heavy hydrocarbon feedstock is in the range of 4:1 to 20:1.

(24) In another embodiment of the present invention, the heavy hydrocarbon feedstock has a CCR content in excess of about 20 wt %.

(25) In still another embodiment of the present invention, the heavy hydrocarbon feedstock is selected from the group comprising of heavy oil, bitumen or mixtures thereof.

(26) In another embodiment of the present invention, the process further comprises separating the product mixture to obtain a light fraction and a heavy fraction and optionally recirculating at least a part of the heavy fraction to the reactor chamber.

(27) In yet another embodiment of the present invention, the step of separating the product mixture to obtain a tight fraction and a heavy fraction is performed in a condenser.

(28) In another embodiment of the present invention, the process further comprises regenerating at least a part of the coke laden particulate material and recirculating the regenerated particulate material to the reactor chamber.

(29) In another embodiment of the present invention, the process further comprises controlling a velocity of the coke laden particulate material and/or controlling a velocity of regenerated particulate material.

(30) In another embodiment of the present invention, the velocity of the coke laden particulate material is reduced using a first cyclone device and the velocity of the regenerated particulate material is reduced using a second cyclone device.

(31) In one embodiment of the present invention, the first and the second cyclone device are the same.

(32) In another embodiment of the present invention, the process comprises 10 to 30 wt % of the coke laden particulate material is regenerated and recirculated to the reactor chamber.

(33) In another embodiment of the present invention, the process comprises the reactor chamber is in the form of an upflow reactor.

(34) In one embodiment of the present invention, the step of providing a particulate material to the reactor chamber comprises maintaining the particulate material in form of a fluidized bed in the reactor chamber.

(35) In yet another embodiment of the present invention, the process comprises maintaining the particulate material in form of a fluidized bed in the reactor chamber comprises feeding a fluidizing medium via at least one inlet located at a first elevation of the reactor chamber and feeding the particulate material via at least one inlet located at a second elevation of the reactor chamber.

(36) In still another embodiment of the present invention, the process comprises the step of dispensing preheated heavy hydrocarbon feedstock in the reactor chamber having dispensing the heavy hydrocarbon feedstock as an atomized spray from at least a top surface of the reactor chamber.

(37) In another embodiment of the present invention, the process comprises the step of dispensing preheated heavy hydrocarbon feedstock in the reactor chamber comprises dispensing the heavy hydrocarbon feedstock as an atomized spray from a plurality of elevations within the reactor chamber.

(38) In another embodiment of the present invention, the process comprises the step of allowing said heavy hydrocarbon feedstock to contact with the particulate material to form a product mixture and a coke laden particulate material comprises maintaining the heavy hydrocarbon feedstock and the particulate material in a conversion zone of the reactor chamber.

(39) The present invention also provides a system for coking and simultaneous upgrading of a heavy hydrocarbon feedstock, comprising: a reactor defining a chamber; a particulate material supply means for supplying heated particulate material to the reactor chamber; a hydrocarbon feedstock supply means for dispensing pre-heated heavy hydrocarbon feed stock to the reactor chamber such that the same comes in contact with the particulate material; a product withdrawal means for withdrawing the product thus formed in the reactor chamber, characterized in that: the hydrocarbon feed stock supply means dispenses the preheated heavy hydrocarbon feed stock as an atomized spray in the reactor chamber; and the reactor chamber allows the heated heavy hydrocarbon feedstock to stay in contact with the particulate material for a predetermined amount of time period such that the product comprises about 70 wt % to about 80 wt % of hydrocarbon having boiling point in the range of 40 to 600 C.

(40) In one embodiment of the present invention, the system further comprises a velocity controlling means for controlling a velocity of the coke laden particulate material and/or controlling a velocity of the regenerated particulate material.

(41) In one embodiment of the present invention, the system having the velocity controlling means comprises a first cyclone device for reducing the velocity of the coke laden particulate material and a second cyclone device for reducing the velocity of the regenerated particulate material.

(42) In another embodiment of the present invention, the first and the second cyclone device are the same.

(43) According to the present invention there is provided a circulating fluid bed cum delayed coking process for upgrading a heavy hydrocarbon feedstock comprising: i) introducing a particulate heat carrier into an upflow or a downflow reactor and contacting the heavy hydrocarbon feedstock; ii) ratio of the particulate heat carrier to feedstock is from about 4:1 to about 20:1; iii) allowing the heavy hydrocarbon feedstock to contact with the heat carrier with a residence time of in the range of 60-900 second with more preferably in the range of 60-600 second and most preferably in the range of 0-300 second to produce a product stream; iv) separating the product stream from the particulate heat carrier; v) regenerating the particulate heat carrier; vi) and collecting a gaseous and liquid product from the product stream, wherein the liquid product exhibits an increased API gravity, a reduced pour point, reduced viscosity and a reduced level of contaminants over that of said feedstock. Preferably, the loading ratio of the method as outlined above is from about 4:1 to about 20:1.

(44) This invention also includes the method as outlined above wherein the heavy hydrocarbon feedstock is either Vacuum Residue or bitumen. Furthermore, the feedstock is pre-heated prior to its introduction into the upflow/down flow reactor.

(45) The present invention also relates to the method as defined above, wherein the temperature of the upflow/downflow reactor is less than 750 C., wherein the pressure is atmospheric to about 3 kg/cm2 (g), and wherein the particulate heat carrier is alumina/silica or mixture or individual material having high heat capacity.

(46) This invention is also directed to the above method wherein the contaminants, including Conradson carbon (coke), BS&W, nickel and vanadium are removed from the feedstock or deposited onto the heat carrier incorporated with weak acid sites.

(47) The present invention is also directed to an upgraded heavy hydrocarbon feedstock characterized by the following properties: i) an API gravity from about 13 to about 23 and feed CCR in the range of 0.1-30 wt %; ii) a density from about 0.88 to about 0.98gm/cc; iii) a viscosity at 40 C. centi stokes (cSt) from about 15 to about 300 cSt; and iv) feed containing vanadium content of about 20 to 200 ppm; and v) teed containing Nickel content of about 10 to 100 ppm. More preferably, present invention is restricted for processing feed heavier than 20 wt % CCR feed.

(48) The present invention also pertains to a liquid product obtained is in the range of 70-80 wt % with coke yield in the range of 10-20 wt %. More preferably present invention provides reduction in coke yield by about 10 wt % with increase in 10 wt % liquid yield.

(49) This invention also includes an upflow/down flow reactor for heavy hydrocarbon feedstock upgrading comprising: i) a means for pre-heating the heavy hydrocarbon feedstock; ii) at least one injection means at least one of a plurality of locations along the upflow reactor, the at least one injection means for introducing the heavy hydrocarbon feedstock into the upflow reactor; iii) un inlet for introducing a particulate heat carrier, the inlet located below the at least one injection means, the particulate heat carrier present at a loading ratio of at least 4:1; iv) a conversion section within the upflow reactor; v) a separation means at an outlet of the upflow reactor to separate the gaseous and liquid products from the particulate heat carrier; vi) a particulate heat carrier regeneration means; vii) a particulate heat carrier recirculation line from the regeneration means to the inlet for supplying the particulate heat carrier to said mixing section; viii) a condensing means for cooling and condensing the liquid products;

(50) The present invention also relates to the upflow reactor as defined above, wherein the plurality of locations, includes locations distributed along the length of said reactor. Furthermore, the upflow reactor may comprise a hot condenser means prior to the condensing means. Preferably, the loading ratio is from about 4:1 to about 20:1. The upflow reactor as defined above may also comprise a heavy fraction product recirculation means from the hot condensing means to the injection means of the upflow reactor.

(51) According to the process of the present invention the regeneration of the particulate heat carrier is done only to the extent of 10-30% by weight, while balance 70-90% of heat carrier material is replaced with fresh material.

(52) As per the invention, high heat carrier material of porous acidic clay bonded by alumina with a diluent normal clay, silica and aluminum trihydrate. The porous acidic clay can be produced insitu after calcination of shaped catalyst from kaolinite, bentonite, vermiculite, smectite, montmorillonite, sepiolite and hectorite. Natural beneficiated, clay can be in finely divided form with a size below about 5 microns. Clay can have a two-layer structure having alternating sheets of silica in tetrahedral configuration and alumina in octahedral configuration. These sheets are separated with a gap of 7.13 . Dry atmosphere equilibrated clay has moisture content of about 15 wt %. The clay is a good source for silica and alumina with about 45 wt % of silica and 38 wt % of alumina with empirical formula 2SiO.sub.2Al.sub.2O.sub.3.2H.sub.2O. Clay possesses surface area in the range 10-20 m.sup.2/g and as such does not have any catalytic activity. According to the present invention, this clay has been transformed to porous mild acidic material through high temperature calcination between 500 C. to 1000 C. followed by controlled mineral acid leaching, acid sourced from hydrochloric acid, nitric acid, sulphuric acid, hydrofluoric acid, phosphoric acid and their mixture. Calcined clay can be used or alternately normal clay containing catalyst can be subjected to high temperature calcination while acid leaching is performed on shaped catalyst employing adequate binder and fillers. Acid leaching of catalyst can pores in the range 20-1000 with mild acidity accessible to large hydrocarbon molecules suitable for cracking heavy resin and alkyl aromatics, heavy naphthenic molecules present in heavy feeds.

(53) In accordance with the process of the present invention, the yield of the liquid is greater than 70% by weight due reduction in side branch of Poly Aromatic ring chain structure at the edge and reduce the coke make thereby increasing the liquid through use of a heat carrier having weak acid site that can easily be regenerated thereby enabling the process to convey adequate heat energy for sustaining continuous reaction.

(54) The heat carrier of the present invention is of porous acidic clay that can be produced after calcination and then acid leaching on shaped catalyst (kaolinite, bentonite, illite, vermculite, smectite, montmorillonite). This heat carrier material have specialty to crack the heavier hydrocarbon aromatic ring structure at the edge so as to reduce the coke yield and increase the liquid yield. Normally the cracking does not take at the edge of the ring leading to high coke yield.

(55) According to present invention the liquid product obtained is in the range of 70-80 wt % with coke yield in the range of 10-20 wt %. Further unwanted bottom and coke yield decreases with increase in liquid yield. The present invention has ability to process heavier feedstock with high CCR 20-30 wt % with reduction in coke yield. Typically coke yield is 1.6 time the CCR. In the present invention coke yield with 20 CCR feed is about 20 wt % only and with 10 wt % CCR about 10 wt % only. This is mainly attributed to weak acid site catalyst and process condition.

(56) Table 1 provides result for experiments, which were conducted using VR having CCR 23 wt %. Experiments were conducted at three temperatures i.e, 490, 500 and 510 C., using optimized catalyst formulation at atmospheric pressure.

(57) TABLE-US-00001 TABLE 1 Base + Base + Base + Base HC Base HC Base HC Temperature 490 490 500 500 510 510 C. Gas 10 12 12 14 14 15 Liquid 60 68 58 65 55 63 Coke 30 20 30 21 31 22 100 100 100 100 100 100 *HC Heat Carrier

(58) As can be seen from above table that about 10 wt % of liquid yield is increases. These liquid is valuable product to improve the refinery profitability.

(59) Table 2 illustrates coke required to be burnt for heat balance and e graph for the same is provided as FIG. 2.

(60) TABLE-US-00002 TABLE 2 Coke yield, wt % 30 25 20 15 % of coke burnt 23.5 28.4 35.6 47.8

(61) The process and apparatus does not require any external heat for the operation. In situ heat is generated depending on the feed CCR processed. Accordingly, % of coke burnt can be known and optimum heat recovery could be achieved. It can observed from Table-2 and FIG. 2 that higher the feed heaviness in terms of CCR lower % of coke is required to be burnt for maintaining the process condition and lower the feed heaviness higher % of coke is required to be burnt.