Patent Application
20130032510
This invention relates to the mining industry which deals with extracting and processing bitumen from various sources, and by way of example such extracting and processing is herein focused with the recovery of oil from oil sands, which is also known as “tar sands,” whose bitumen contains sand, clay and moisture, and is mined in open-pit practice.
In open-pit mining, large, hydraulic/electric shovels do the digging and the loading of trucks that deliver the mined oil sands to processing complexes. These complexes use very large quantities of water to wash the sand from the bitumen. After the separation of the sand from the bitumen, the water is too dirty to discharge into a body of water, such as a river, from where the water was derived. Current practice is to store such dirty/oily water in ponds, which are called tailings ponds, that can be as big as the mines themselves, creating a major negative environmental problem. Further, the processing complexes utilize large quantities of natural gas to heat the water to about 170° F. to wash out the bitumen as a first step and is followed by a second step to heat the water into steam to about 900° F. and compress the raw bitumen to some 1,500 PSI to upgrade the oil in the bitumen by subtracting carbon to result in a lighter hydrocarbon liquid.
The main object of the present invention is to produce valuable, desulfurized light liquids directly from open-pit mining of crushed run-of-mine bitumen.
Another object of this invention is to do away with the use of water in the processing of the oil sands which contain the bitumen.
Therefore another object of the present invention is to provide a superior technology and apparatus that will lower the processing cost of oil sand bitumen.
Yet another object of the instant invention is to eliminate the use of tailings ponds which contain clay and sand particles that take several years to settle, and when they do settle, produce bodies of water containing toxic chemicals such as naphthenic acid and polycyclic hydrocarbons.
Further another object of the present invention is to reduce the energy consumption in the processing of bitumen from the oil sands.
Still another object of the instant invention is to produce a clean, hydrogen rich synthetic gas as a by-product that can be converted to a clean transport fuel such as gasoline, or dimethyl ether which can replace dirty diesel to fuel the large trucks that transport the oil sands from where it is mined to the processing complexes.
Further still another object of the present invention is to provide an environmentally closed method and equipment to carry the method.
Further yet another object of the instant invention is to provide a continuous method and equipment to carry the method.
It is therefore another object of the present invention to co-produce electric power as a by-product that is useful in the recovery and processing of the bitumen.
It is yet another object of the instant invention to co-produce a fertilizer as a by-product which is useful in the acceleration of mined land reclamation.
It is still another object of the present invention to co-produce a fuel in the form of a char from the mined bitumen which is utilized as the energy source in the pyrolysis step which de-asphalts the bitumen.
Other objects of this invention will appear from the following detailed description and appended claims. Reference is made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the various figures.
Reference is made to
Pyrolyzer 10 is made up of charger 20, pyrolyzing chamber 21, radiant zone 22, downcomer 23, and flow control valve 24, from which bifurcated pipe 25 forms a delivery pipe assembly, with pipe 26 connecting downcomer 23 thence to char gasifier 11 by way of control valve 28, and pipe 27 connecting downcomer 23 to char quencher 12 by way of control valve 29.
Gasifier 11 comprises vessel 30, which is equipped with injection points at different levels for a gas containing oxygen, such as air, to react with hot char to produce a fuel gas; gasifier 11 possesses at its bottom discharge cooler 31, with exit port 32. Below cooler 31, lockhopper 33 is provided, which is controlled by upper valve 34 and by lower valve 35. At about mid-point of gasifier 11, a special manifold marked by numeral 36 serves for the injection of flue gases containing CO2 for reducing the CO2 into 2CO. Quencher 12 comprises vessel 37, which is equipped with multi-level manifolds, like manifold 38, that gradually cool the char below ignition point prior to being periodically discharged to the atmosphere by means of valve 39.
The equipment to feed the mined raw materials is marked by numeral 19, and comprises skip 40, which elevates the raw bitumen that contains sand, clay and moisture from ground to conveyor 42 and skip 41, which elevates the char (fuel) from ground to conveyor 43, which in turn conveyor 42 discharges to feeder 44 and conveyor 43 discharges to feeder 45.
Gas cleanup 13 is made up of three vessels, marked by numerals 46, 47, and 48. Vessel 46 cracks and simultaneously desulfurizes the volatile matter from pyrolyzer 10; vessel 47 cleans the fuel gas made up of nitrogen (N2) and carbon monoxide (CO) gas from gasifier 11; and vessel 48 serves to regenerate the sorbent and produce elemental sulfur directly. All three vessels are equipped with feeders denoted by numeral 49. Vessel 48 interconnects with vessels 46 and 47 via the inverted Y-pipe that is marked by numeral 50, which is equipped with diversion valves 51. Gas cleanup 13 is equipped with pneumatic transporters 52 to convey the spent sorbent from vessels 46 and 47 to regenerator 48.
Cyanogen make-up equipment 16 comprises reactor 53 “A” and reactor 53 “B” with gas temperature moderator denoted by numeral 54 being upstream of “A” and “B,” and chiller-liquefier which is denoted by numeral 55 being downstream. A separator marked by numeral 56 is provided to segregate the liquefied cyanogen from the unreacted gases which are directed (not shown) to pyrolyzer 10.
Downstream of separator 56, oxamide maker 17 is located. It consists of reactor 57, settling tank 58, filter press 59, drier 60, and stacker 61. Pump 62 is provided to separator 56 to pump the liquefied cyanogen to evaporator 63, and pump 64 serves to circulate the liquid catalyst to the top of reactor 57; a heater denoted by numeral 65 serves to adjust the temperature of the liquid catalyst.
The mercury removal system marked by numeral 18, which consists of activated carbon beds, comprises beds “a” and “b,” with the practice being when bed “a” is in absorption of mercury, bed “b” is in regeneration mode, and when bed “b” is in absorption, while bed “a” is in regeneration mode.
The electric power generation system in this invention, marked by numeral 15, is preferably fueled with a clean, lean gas (fuel gas) fed from cleanup vessel 47 and comprises gas turbine numeral 66, heat recovery steam generator 67, and steam turbine 68, forming a combined cycle configuration which is a most efficient way of generating power.
Referring now to
It is to be noted that in providing lance 71 wherein the char charged is combusted under suppressed conditions (in a pressurized, controlled reducing atmosphere), heat transfer within chamber 21 is markedly improved, thus enhancing the rate at which the bitumen, containing sand, clay and water, devolatilizes into volatile matter, while vigorously cracking tars to such an extent that carbon is deposited on the sand and clay while the water turns into water-gas (H2+CO) within chamber 21. Further, the bitumen is heated peripherally by means of injection nozzles disposed through shell 77 and refractory 75, one of which being marked by numeral 80, with such nozzles being supplied with a gas containing oxygen furnished by manifold 79, thus providing direct, pressurized, bi-directional, efficient heating that increases the release of the volatile matter from the bitumen to such an extent that virtually all the oils in the bitumen are recovered in vapor form while its tar is carbonized, producing carbonized sand and clay.
In the instant application, wherein carbon in the char (as a core within chamber 21) is combusted in a pressurized reducing atmosphere, the combustion of bitumen which surrounds the core is virtually prevented. To achieve this objective, numeral 21 is the pyrolyzing chamber, numeral 20 is the charger, numeral 81 is the feed hopper, numeral 69 is the ram, numeral 70 is the mandrel, numeral 71 is the injection lance, numeral 82 is the nozzle at the tip of lance 71, and numeral 83 is one of the several nozzles disposed at the side of lance 71, numeral 72 is the char fuel, numeral 73 is the charged bitumen containing sand, clay and water, and numeral 75 is the refractory/insulation which is configured as a monolithic structure that is reinforced with metallic needles such as stainless steel needles, marked by numeral 84 (shown in SECTION A-A), somewhat similar to imbedding steel wire in reinforced concrete; this structure is cast in place against shell 77.
In the case of heating the material peripherally directly by combusting char (not shown), oxygen is introduced through shell 77 by means of injectors, one such injector being marked by numeral 80 supplied by manifold 79. When combustion takes place peripherally and the material is bitumen, it is possible to also charge char around the perimeter of the bitumen annulus by providing an additional mandrel that circumscribes ram 69 to form a ring of char around the periphery of the bitumen. In so doing, the combustion effected by injectors, such as injector 80, consumes the ring of char, instead of combusting the bitumen.
In the case of heating the material peripherally indirectly, numeral 74 represents the manifold for distributing hot heating gas into a plurality of small-diameter flues installed in refractory/insulation 75, one such flue being marked by numeral 76 carrying hot gases that heat refractory 75, which in turn heats indirectly the bitumen marked my numeral 78 shown in Section A-A. It is to be noted that towards the exit end of pyrolyzing chamber 21, the bitumen has been completely devolatilized, yielding a residual consisting of a char made up of carbonized sand and clay devoid of any oil. Referring to
To describe the operation of this invention based on extensive test work that had taken place and referenced hereinafter begins with using unprepared, crushed run-of-mine bitumen preferably of three inches and under that is directly fed into a battery of pyrolyzers where the cracking of asphalt results in a tar-free bitumen in the form of volatile matter containing a hydrogen rich, non-condensable raw syngas together with vaporized light liquids and incandescent char. The syngas and vaporized light liquids are desulfurized and upgraded in a first hot gas cleanup, while a part of the hot char is gasified with air into a fuel gas and oil-free, tar-free tailings containing clean sand and clean clay; the other part of the char is used as fuel for heating the pyrolyzer. The fuel gas from the gasifier is passed through a second hot gas cleanup, producing a clean, desulfurized lean gas which is ideal to generate clean, efficient electric power with the emitted CO2 from power generation collected and converted to slow-release fertilizer that can be mixed with top soil, which had been removed prior to mining the bitumen, to form a rich top soil. The oil-free, tar-free tailings, consisting of clean sand and clean clay, are used in the reclamation of the open-pit mine and topped with the rich soil to enhance and accelerate plant growth to create forest land.
The test work performed in the Applicant's pilot in cooperation with Sun refining proved that the method described herein, which uses CaO as sorbent, produced light liquids from cracking residuum (heavy bitumen) from its Philadelphia Refinery against CaO as sorbent. Such light liquids were referred to by Sun as “excellent feedstocks and can be separated by a simple distillation process into valuable intermediates”; see Exhibit 1, page 1 of 2.
Data that was produced by way of the tests (see Exhibit 1, page 2 of 2) showed that the Ramsbottom Carbon (by weight percentage) of the residuum was converted from 18.2% to 1.24% in test Run #3, to 0.59% in test Run #4, and to 0.31% in test Run #5. Further, for the Pour Point temperature in ° F., the residuum was 145° F., and in tests #3, #4, and #5, the temperature was reduced to −20° F. Also, the INITIAL BOILING POINT of the residuum dropped from 802° F.: in test #3 to 108° F., in test #4 to 154° F., and in test #5 to 135° F. This data show that the method herein described—which is based on the replication of the test work performed, except at commercial scale—should produce outstanding results in producing light liquids from bitumen. It is also important to disclose herein that the syngas (Rich Gas Sample—Test Run #3) produced in Mole % as follows: H2—57.3%; CH4—36.6%; N2—3%; C2H4—1.8%; CO—1.6%; and CO2—only 0.7%.
With respect to residual bitumen after pyrolysis, tests were conducted in 1997 at Applicant's Process Development Unit (Exhibit 2) making metallurgical coke from coal; the coke produced was tested for various properties including residual volatile matter after pyrolysis. In testing the coke made from Bethlehem Steel's coal, the residual volatile matter was 0.58%, and with coke made from U.S. Steel's three coals, the residual volatile matter was 0.55% from Blue Tag Coal, 0.48% from Low-Vol coal, and 0.70% from White Tag coal; see Exhibit 3. In the tests conducted, whether the feedstock was heavy oil (bitumen) or coal, these feedstocks were pyrolyzed in sealed tubes in which cracking of tars took place as proposed herein; in the case of sulfur removal, the gas produced had no H2S, as reported in Exhibit 1, page 1 of 2. Production of elemental sulfur during regeneration was reported by Sun; see Exhibit 4, and the chemistry for such results are published in The Making, Shaping and Treating of Steel, 11th edition; see Exhibit 5.
In conclusion, based on the test work done and the herein description, the objectives listed towards the beginning of this disclosure are achievable. It is submitted herein that the instant method and apparatus provide major improvements over the conventional practice of processing open-pit mining of bitumen including oil sands. The details of construction mentioned above are for the purpose of description and not limitation, since other configurations are possible without departing from the spirit of the invention. Further, other materials besides bitumen from oil sands can be processed in the apparatus herein described.
