WO2010059802A2

WO2010059802A2 - Process and system for processing waste product from oil sand extraction operations

Info

Publication number: WO2010059802A2
Application number: PCT/US2009/065112
Authority: WO
Inventors: Christianne Carin; Alvin W. Fedkenheuer
Original assignee: Earthrenew, Inc.
Priority date: 2008-11-21
Filing date: 2009-11-19
Publication date: 2010-05-27
Also published as: AR074389A1; WO2010059802A3; CL2009002110A1; PE20100619A1

Abstract

The present disclosure provides methods and systems for processing oil sand waste material feedstock from an oil sand bitumen extraction operation. The oil sand waste material feedstock includes contaminated sand and water. A gas turbine generator is operated to produce electricity and exhaust gases. The exhaust gases are used to remove contaminants from the oil sand waste material feedstock and to evaporate at least some of the water. The evaporated water can be recycled and reused as part of the oil sand bitumen extraction operation. Waste heat from the exhaust gas can be used to preheat heated water used in the oil sand extraction operation.

Description

PROCESS AND SYSTEM FOR PROCESSING WASTE PRODUCT FROM OIL SAND EXTRACTION OPERATIONS

This application is being filed on 19 November 2009, as a PCT International Patent application in the name of EarthRenew, Inc., a U.S. national corporation, applicant for the designation of all countries except the US, and Christianne Carin, a citizen of Canada, and Alvin W. Fedkenheuer, a citizen of the U.S., applicants for the designation of the US only, and claims priority to U.S. Provisional patent application Serial No. 61/116,899, filed November 21, 2008.

Technical Field

The present disclosure relates generally to processes, systems and equipment for economically processing waste from oil sand extraction operations.

Background

Oil sands (i.e., tar sands or bituminous sands) are mixtures of sand or clay, water and a form of petroleum called bitumen or very heavy oil. Oil sands represent a large percentage of the world's total petroleum resource. The largest reserves of oil sands exist in Canada (e.g., the Canadian Athabasca Oil Sands) and in Venezuela (e.g., the Venezuelan Orinoco Tar Sands).

Bitumen is a very slow flowing petroleum product and cannot typically be effectively extracted using conventional oil drilling technology.

Therefore, until fairly recently, oil sands provided only a small fraction of the total synthetic crude oil consumed worldwide. However, with the advent of improved technology and with increasing crude oil prices, synthetic crude oil is being processed from oil sand at an ever increasing rate. In certain types of oil sands, water surrounds the grains of sand thereby isolating the sand from the bitumen. This isolating layer of water facilitates the use of water-based extraction techniques. A typical water-based extraction technique involves injecting hot water into a volume of oil sand. After the hot water has been added to the oil sand, the mixture is agitated which causes the bitumen to separate from the sand and water. The separated bitumen attaches to air bubbles and floats to the surface of the mixture. Chemicals such as NaOH can be added to the mixture to enhance the separation process. The bitumen is skimmed from the top of the mixture and is further treated (e.g., with naphtha or other solvent) to remove remaining water and minerals. Thereafter, the bitumen is further processed to produce synthetic crude oil. Using advanced techniques, over 90% of the bitumen can be extracted from the oil sand. A common technique for extracting oil sand involves using surface mining techniques. Surface mining techniques typically involve removing the overburden from the oil sand. Once the overburden has been removed, the oil sand is extracted using strip mining techniques or shovel-and-truck operations. For deeper reserves of oil sand, surface mining techniques are less efficient. For extracting such reserves, several in-situ techniques have been developed such as cold flow, cyclic steam stimulation, steam assisted gravity drainage, vapor extraction process and toe-to-heel air injection.

Using current technology, relatively large amounts of energy are needed to produce synthetic crude from oil sands. Further technology is needed to improve the energy efficiency associated with processes for producing synthetic crude from oil sands.

The extraction of bitumen from oil sands also raises a number of environmental concerns. For example, extraction processes such as strip mining can result in the damage of expansive areas of land. Additionally, tailings produced in the extraction process often end up in tailings/settling ponds. Such tailings ponds are highly hazardous and present a danger to wildlife such as water fowl and also pose a risk to contaminating aboveground and underground water resources. Moreover, existing processes for generating crude synthetic oil from oil sands use enormous amounts of water most of which can end up in tailings ponds. Additionally, the tailings sands produced during the extraction process include leachable contaminants such as residual hydrocarbons that can be a significant source of groundwater contamination if the tailings sands are deposited back into the ground.

It is apparent from the above that there is a substantial unmet need for environmentally and economically acceptable technologies for assisting in the processing/recycling of waste materials generated from oil sand bitumen extraction processes. The present disclosure is directed to methods, apparatuses, and systems for meeting some or all of these needs. Summary

The present disclosure relates to methods, systems and apparatuses for efficiently processing waste materials generated from oil sand bitumen extraction processes. The present disclosure further provides economical methods, systems and apparatuses for effectively processing water and sand from bitumen extraction processes. The present disclosure further provides methods, systems and apparatuses for effectively processing material from tailings ponds produced during the extraction of bitumen from oil sands. In one aspect, the present disclosure provides a method for processing waste material feedstock generated from an oil sand bitumen extraction operation comprising operating a gas turbine generator to produce electricity and exhaust gases; and contacting the waste material feedstock with the exhaust gases to treat the waste material feedstock. In another aspect, the disclosure provides a method for processing tailings from an oil sand bitumen extraction operation. The tailings include contaminated sand and water. The method includes operating a gas turbine generator to produce electricity and exhaust gases. The method also includes using the electricity in the oil sand extraction operation, selling the electricity to a power company or both. The method further includes contacting the contaminated sand and water with the exhaust gases from the gas turbine generator to remove contaminants from the sand and to evaporate at least some of the water. The evaporated water can be recycled and reused as part of the oil sand extraction operation. Waste heat from the exhaust gas can be used to preheat heated water used in the oil sand extraction operation, m certain embodiments, the exhaust gases can have a temperature greater than 1,000⁰F. After treatment by the exhaust gases, the sand can be substantially free of leachable contaminants and can readily be used for reclamation projects or elsewhere without presenting the danger of further contaminating the environment. hi still another aspect of the present disclosure, the present disclosure provides an apparatus for drying and/or treating waste material feedstock from an oil sand extraction operation comprising a gas turbine in combination with a heating vessel adapted for receiving the waste material feedstock and also for receiving the exhaust gases from the gas turbine. In one embodiment, outside air is precluded from entering the heating vessel as the exhaust gas flows through the heating vessel and treats the waste material feedstock. In other embodiments, at least some outside air may be introduced into the heating vessel during treatment of the waste material feedstock with the exhaust gas. The heating vessel optionally includes structure adapted for drying and/or treating the waste material feedstock by direct contact of the waste material feedstock with the exhaust gases. In certain embodiments, the gas turbine and heating vessel can be portable or can be provided as part of a portable processing unit or units. A further aspect of the present disclosure relates to methods and systems for treating settling/tailings ponds from mining operations, drilling operation and/or oil extraction operations.

Still another aspect of the present disclosure relates to methods and systems for reducing the size of settling/tailings ponds generated from mining operations, drilling operation and/or oil extraction operations.

A further aspect of the present disclosure relates to methods and system for eliminating the use of open settling ponds/tailings ponds for holding waste from mining operations, drilling operation and/or oil extraction operations.

The above aspects and other aspects will be apparent to one of skill in the art from the disclosure herein.

Brief Description of the Drawings

Fig. 1 is a schematic diagram of a system for treating waste material feedstock generated from an oil sand bitumen extraction operation in accordance with the principles of the present disclosure; Fig. 2 is a schematic diagram of another system for treating waste material feedstock generated from an oil sand bitumen extraction operation in accordance with the principles of the present disclosure; and

Fig. 3 is a schematic diagram of another system for treating waste material feedstock generated from an oil sand bitumen extraction operation in accordance with the principles of the present disclosure. Detailed Description

The present disclosure provides new technology in the form of processes, apparatuses and systems for conversion of oil sand waste material feedstock to useful, environmentally acceptable materials and products. The present disclosure also provides new technology in the form of processes, apparatuses and systems that allow for the treatment of oil sand waste material feedstock in an efficient and economically viable way. The present disclosure also provides new technology that allows for the efficient recycling of water used in oil sand extraction operations. The term "oil sand waste material feedstock" is used herein to mean and include waste material generated from operations used to remove bitumen from oil sand. Example oil sand waste material feedstock includes contaminated sand and water. As used herein, the term "sand" includes sand, clay or other geological materials excavated as part of an oil sand extraction operation. The oil sand waste material feedstock also includes waste water generated as part of the oil sand bitumen extraction operation. Sources of the waste water include water inherently present in the oil sand as well as water added to the oil sand during processing operations to facilitate extracting bitumen from the sand.

Figure 1 shows an oil sand processing system 20 in accordance with the principles of the present disclosure. The oil sand processing system 20 includes a first subsystem 22 directed toward processing the oil sand to remove bitumen and to ultimately process the bitumen into synthetic crude. The oil sand processing system 20 also includes a second subsystem 24 for processing oil sand waste material feedstock generated from the first subsystem 22. The second subsystem 24 also provides electrical power that can be used by the first subsystem and further provides recycled water and recaptured heat that can be used by the first subsystem 22.

Referring still to Figure 1, the first subsystem 22 includes an oil sand excavation location 30 at which oil sand is excavated from the ground. For example, the oil sand excavation location 30 can include a surface mining operation where overburden is removed to expose the underlying oil sand, and oil sand is excavated using conventional surface mining equipment such as strip drag lines, bucket-wheel excavators, conveyer belts, power shovels, dump trucks or other equipment. Once excavated, the oil sand is moved to a crushing station 32 where the oil sand is mechanically crushed, screened and otherwise processed to reduce the particulate size of the oil sand. At hot water slurry location 34, hot water is added to the crushed oil sand to provide a hot water/oil sand slurry that can be piped to an extraction plant 36. The hot water is supplied from a source of hot water 41 (e.g., a hot water tank/boiler heated by a heat source such as a burner).

At the extraction plant 36, the slurry is agitated in tanks to release the bitumen from the sand. A chemical additive such as NaOH can be added to the slurry to enhance the amount of bitumen released from the sand. As the bitumen is released from the sand, the bitumen attaches to air bubbles and is carried to the tops of the agitation tanks. The bitumen is skimmed from the tops of the agitation tanks and is transported to a subsequent petroleum processing location 39 where the bitumen is upgraded to synthetic crude oil.

The remaining portions of sand and water provided in the agitation tanks (i.e., the tailings) are conveyed to a tailings oil recovery location 38 where additional bitumen is removed and is conveyed to the petroleum processing location 39. From the tailings oil recovery location 38, the tailings are conveyed to a settling pond 40. At the settling pond 40, some of the water is removed (e.g., using decanting technology) and recycled back to the source of hot water 41 for use at the hot water slurry location 34. Make-up water from another water source can also be provided to the source of hot water 41.

The second subsystem 24 includes a turbine generator 60 that supplies hot exhaust gas to a heating vessel arrangement 62 (e.g., a drying arrangement) used to dry/treat oil sand waste material feedstock from the settling pond 40. The turbine generator 60 includes a combustor 64 where a fuel such as natural gas is combusted. The exhaust gas from the combustor 64 drives an exhaust turbine 66 that rotates a drive shaft 67. The drive shaft 67 drives a compressor turbine 70 that moves intake air under compression into the combustor 64. An air filter 72 is typically used to clean the intake air fed into the combustor. The drive shaft 67 also drives an electrical generator 74 for generating electrical power that can be used to power various operations performed at the first and second subsystems 22, 24, and/or can be sold to another party (e.g., a utility company). The hot exhaust gas from the turbine is preferably used to provide heat to the heating vessel arrangement 62 for drying and treating the oil sand waste material feedstock. In one embodiment, the hot exhaust gas is passed though the heating vessel arrangement 62 and comes in direct contact with the oil sand waste material feedstock within the heating vessel arrangement. Within the heating vessel arrangement, water within the oil sand waste material feedstock can be evaporated and hazardous/leachable materials within the oil sand waste material feedstock can be volatized by the heat from the exhaust gas. Preferably, the oil sand waste material feedstock is heated to a temperature high enough to volatize hazardous materials such as bitumen within the oil sand waste material feedstock. The oil sand waste material feedstock exiting the heating vessel arrangement preferably has been treated so that leachable materials such as bitumen or other contaminants contained therein have been volatized or otherwise driven off, removed or rendered non- leachable. Thus, the sand exiting the heating vessel arrangement is preferably non- hazardous and can be readily reclaimed without concern of contaminating the environment.

Upon exiting the heating vessel arrangement, the solids (i.e., the treated sand) are separated from the gas stream at a solids separator 80. The gas stream may include exhaust gas from the turbine generator 60 as well as water vapor and other volatized components (e.g., volatized hydrocarbons) from the oil sand waste material feedstock. Heat exchanging equipment can be used to recapture heat present in the sand that exits the solids separator 80. The gas stream exiting the solids separator 80 is conveyed to one or more gas separating operations 82. For example, hydrocarbons (e.g., bitumen) vaporized at the heating vessel arrangement 62 can be removed from the gas stream using oil separation technology such as oil coalescing filter arrangements, distillation type separators, or other separating arrangements. Similarly, the water vapor in the gas stream can be removed and recycled using separation technology such as a water condensing arrangement. One or more heat exchangers 83 can be used to recapture heat present in the gas stream. The heat exchangers 83 may be incorporated as part of the separation technology or may be independent of the separation technology. Heat recaptured from the gas stream can be used at any location within the subsystems 22, 24 where an auxiliary or additional heat source is needed. For example, the recaptured heat can be used to preheat water that is injected into the crushed/screened oil sand at step 34. After passing through the one or more gas separating operations 82, the gas stream can be routed through one or more scrubbers 84 before being discharged to atmosphere.

The heating vessel arrangement 62 can include one or more heating vessels operated in either a batch or continuous drying operation. In certain embodiments, the heating vessels can be operated at different temperatures from one another and used to perform different treatment/drying functions. For example, one heating vessel can be operated at lower temperatures and used primarily for driving water from the oil sand waste material feedstock while a second heating vessel can be operated at higher temperatures and used primarily for volatizing contaminants from the oil sand waste material feedstock after the oil sand waste material feedstock has been dried. Additionally, one or more turbine generators may be used to provide hot exhaust gas for use in heating the heating vessels. For example, a first turbine generator having a lower temperature exhaust gas may be used to heat a first heating vessel adapted for driving water from the oil sand waste material feedstock while a second turbine generator having a higher temperature exhaust gas may be used to heat a second heating vessel used to volatize contaminants present in the oils sand waste material feedstock.

A number of different techniques can be used to remove sand from the settling pond 40. For example, excavating equipment can be used to drag, scoop or otherwise remove sand from the settling pond 40. Alternatively, for certain applications, the sand may be pumped as a slurry from the settling pond. In still other cases, the pond may be dried or partially dried before removal of the sand from the pond and conveyance of the sand to the heating vessel arrangement 62. Certain preprocessing steps may be utilized before loading the sand from the settling pond 40 into the heating vessel arrangement 62. For example, further crushing, grinding and screening operations may be conducted. Additionally, process steps may be undertaken to control the moisture content of the sand being loaded into the heating vessel arrangement 62. For example, structures such as belt presses, filters, centrifuges, strainers, screening devices or other mechanisms can be used to remove at least some water from the sand before loading the sand into the heating vessel arrangement 62. Additionally, depending on the chemical composition of the sand, it may be desired to chemically treat the sand before loading the sand into the heating vessel. For example, the sand may be chemically treated to neutralize any caustic chemicals present in the sand prior to loading the sand in the heating vessel arrangement 62.

The exhaust output from the turbine generator 60 is preferably connected to the heating vessel arrangement 62 by a connection conduit 63. An optional air inlet (not shown) can be in the conduit 63, in the heating vessel arrangement 62 or elsewhere for purging the heating vessel arrangement 62 or other system, for startup or shutdown or for other reasons, particularly when either the exhaust gases or oil sand waste material feedstock is not present in the heating vessel arrangement 62. However, when both are present, any such air inlet is preferably closed and not used in order to substantially preclude the introduction of air into the heating vessel arrangement 62 and to preclude significant oxidation of materials being processed in the heating vessel arrangement 62.

An optional silencer 65 can be provided downstream of the turbine generator 60. Typically, the silencer 65 may be used for startup, shutdown or during those times when the turbine generator 60 is operating in a mode (e.g., a heating vessel by-pass mode) in which the exhaust gas does not pass through the heating vessel arrangement 62. However, the heating vessel arrangement 62 will function as a silencer during normal operation of the system. In certain embodiments, a blower or other device is used to lower exhaust pressure within the heating vessel arrangement and the turbine generator to maximize turbine efficiency.

In certain embodiments, the volatilized hydrocarbons in the gas stream exiting the drying arrangement may be separated from the gas stream and used as fuel at one or more of the heat sources present in the system. For example, the separated volatile hydrocarbons can be used to provide fuel to a burner of a boiler for heating the water used to form the hot slurry at location 34. Additionally, the separated volatiles could be used as fuel for a burner that provides auxiliary heat to the heating vessel arrangement 62. Moreover, in certain embodiments, the separated volatilized hydrocarbons can be routed through the combustion chamber of the turbine generator and burned therein. In certain embodiments, the volatile hydrocarbons separated from the main gas stream can be concentrated in a stream of gas having a much lower flow rate than the main gas stream flowing through the system to facilitate effectively using the volatile hydrocarbons as fuel. Figure 2 shows an alternative subsystem 124 adapted for treating oil sand waste material feedstock from the subsystem 22 of Figure 1. The subsystem 124 includes first and second heating vessels 62a, 62b positioned in series. The heating vessels 62a, 62b are heated by hot exhaust gas from a turbine generator 60 of the type described with respect to Figure 1. The heating vessel 62a is adapted for driving moisture form the oil sand waste material feedstock, and the heating vessel 62b is adapted for volatizing hydrocarbons present in the dried oil sand waste material feedstock.

In operation of the subsystem 124, hot exhaust from the turbine generator 60 is conveyed directly into the second heating vessel 62b. It is preferred for oil sand waste material feedstock within the second heating vessel 62b to be heated to a temperature high enough to volatilize bitumen or other leachable contaminants within the oil sand waste material feedstock (e.g., at least 977 ⁰F). From the second heating vessel 62b, the oil sand waste material feedstock is conveyed to a solids separator 80b where the sand is separated from the gas stream. The gas stream includes exhaust gas from the turbine, and any gaseous material volatilized at the second heating vessel 62b. As with previous embodiments, any remaining heat present in the treated sand can be recovered using heat recovery technology such as heat exchangers. The gas stream proceeds from the solids separator 80b to a hydrocarbon separator/concentrator 126. At the hydrocarbon separator/concentrator 126, hydrocarbons can be separated and collected in liquid form. Hydrocarbon material collected in this manner can be processed into usable products such as synthetic crude oil or other petroleum-based products such as asphalt or other materials. Alternatively, the hydrocarbon material can be concentrated into a separate lower flow stream of gas that can be combusted at the gas turbine or at any auxiliary heat sources (i.e., burners) provided in the system. The gas stream exiting the hydrocarbon separator/concentrator 126 has a relatively high temperature and can be routed back to the first heating vessel 62a. The first heating vessel 62a can operate at a lower temperature than the second heating vessel 62b and is adapted for driving water from the oil sand waste material feedstock removed from the settling pond 40. In certain embodiments, the oil sand waste material feedstock exiting the first heating vessel 62a is dried and has a temperature in excess of 212°F. The gas stream and the oil sand waste material feedstock from the first heating vessel 62a and are separated at a solids separator 80a. The dried sand from the solids separator 80a is fed into the second heating vessel 62b where it is heated to a higher temperature so as to volatilize contaminants contained therein. The water vapor driven from the oil sand waste material feedstock at the first heating vessel 62a can be carried to a condenser 128 where water from the settling pond 40 or make-up water is preheated before being heated at the tank 41 and used to form a hot water slurry at location 34. Steam condensed at the condenser 128 can also be directed into the tank 41 so as to be recycled. After passing through the condenser 128 where the water is removed, the gas stream can be directed through a scrubber 84 to remove any other unwanted emissions before the gas stream is discharged to atmosphere. hi startup of the subsystem 124, oil sand waste material feedstock from the bottom of the settling pond is fed into the first heating vessel 62a and heated sufficiently to drive off the moisture contained therein as water vapor. During startup, the second heating vessel 62b is empty but is preheated by the exhaust gas flowing therein from the gas turbine 60. Once the oil sand waste material feedstock within the first heating vessel 62a has been adequately dried, the dried sand is moved to separator 80a where the dried sand is separated from the gas stream. The dried sand is then moved to the second heating vessel 62b and the process continues as described in the previous paragraph.

Fig. 3 shows a further subsystem 224 for treating oil sand waste material feedstock from the subsystem 22 of Figure 1. hi a preferred embodiment, the subsystem 224 is adapted to facilitate recycling process water from the waste material feedstock and includes a heating vessel arrangement 262 in which water from the settling pond 40 is evaporated. As shown in Fig. 3, the settling pond has a top layer 40a including bitumen/hydrocarbons that float to the pond surface, a middle layer 40b including water containing dissolved and suspended materials, and a bottom layer 40c including solids that settled out of the process water. Preferably, water is drawn from the middle layer 40b and transferred (e.g., piped) to the heating vessel arrangement 262 where the water is evaporated. Optionally, filters, strainers, centrifuges or other separation devices can be used to remove at least some suspended solids from the water prior to the water being transferred into the heating vessel arrangement 262. The water vaporized at the heating vessel arrangement 262 can be condensed at a condenser 265 which can also be used to pre-heat the water from the settling pond 40 before the water is transferred into the heating vessel arrangement 262. Heat for the heating arrangement 262 can be provided by a gas turbine generator 60 arrangement of the type described with respect to Fig. 1. Solids (e.g., salts or other materials precipitated from the water) or water having a high concentration of salts (e.g., brine) or suspended solids can be collected from the heating vessel arrangement 262 and further processed, stored or otherwise disposed. The recovered water can be re-used as process water or used elsewhere in the system. In one embodiment, the water from the settling pond 40 can be sprayed into the heating vessel arrangement 262. Preferably, the sprayed water makes direct contact with hot exhaust from the gas turbine generator 60 within the heating vessel arrangement 262, and preferably outside air is substantially precluded from entering the heating vessel arrangement 262. The water can be sprayed in various directions within the heating vessel arrangement by structures such as one or more spray nozzles, hi certain embodiments, the water can be sprayed upwardly within the heating vessel arrangement 262, downwardly within the heating vessel arrangement 262, horizontally within the heating vessel arrangement 262 or angled relative to horizontal within the heating vessel arrangement 262. Hot exhaust flow within the heating vessel arrangement 262 can flow upwardly within the heating vessel arrangement 262, downwardly within the heating vessel arrangement 262, horizontally within the heating vessel arrangement 262 or angled relative to horizontal within the heating vessel arrangement 262. The water can be sprayed in the same direction as the direction of exhaust flow, in the opposite direction of exhaust flow (i.e., counter flow), laterally across the direction of exhaust flow, or angled across the direction of exhaust flow. In other embodiments, water can be transferred into the heating vessel arrangement 262 by a conveyor arrangement including one or more vessels (e.g., open topped vessels) capable of holding water and configured for allowing water to be evaporated from the vessels upon entry into the heating vessel arrangement 262.

As indicated above, systems in accordance with the principles of the present disclosure can be used to treat oil sand waste material feedstock from a settling pond. By using aspects of the present disclosure, the size of the settling pond can be greatly reduced as compared to settling ponds used in existing oil sand bitumen extraction operations. In certain cases, settling ponds can be eliminated by feeding the oil sand waste material feedstock from the bitumen recovery operations directly to the heating vessel arrangement. Alternatively, because lower volumes of oil sand waste material will likely need to be stored for an extended time, enclosed tanks or other types of enclosed storage vessels could be used to hold the oil sand waste material until the oil sand waste material is fed as feedstock into a heating vessel arrangement in accordance with the principles of the present disclosure.

Systems in accordance with the principles of the present disclosure can also be used to treat material from ponds (e.g., tailings ponds, settling ponds, storage ponds) generated from other types of mining operations, drilling operations, or oil extraction operations. Further, systems in accordance with the principles of the present disclosure can be used reduce the size of ponds generated from other types of mining operations, drilling operations, or oil extraction operations. Moreover, systems in accordance with the principles of the present disclosure can eliminate the use of open ponds for storing waste generated from other types of mining operations, drilling operations, or oil extraction operations, or can enable the use of enclosed vessels to store the waste. Example types of mining operations, drilling operations and oil extraction operations to which systems in accordance with the principles of the present disclosure can be applied include coal bed methane drilling, coal processing for power plants, potash mining, clay and mineral mining as well as conventional oil and gas field sludge and settling ponds.

According to the present disclosure, a most efficient way of providing the hot gases for contact with waste material feedstock is to use the exhaust from a gas turbine, and preferably a gas turbine electric generator. The gas turbine can be fueled from locally available conventional fuel sources, because conventional fuels provide the most efficient, reliable and controllable operation of the gas turbine. The electricity produced from the gas turbine generator can be sold back into the local power grid as a revenue source and/or can be used internally in the operation of the system or in other nearby operations as a supplemental source of power, hi certain embodiments, it can be more efficient to merely sell the electric power produced to the local power grid. This enables varying the operation of the processes and equipment of systems of the type disclosed herein in the most efficient and effective manner for treatment of waste material feedstock to produce the desired quality and quantity of products without concern for or being constrained by any particular minimum or necessary level of electricity output or the need for an unchanging level of electricity output. One important feature used by preferred embodiments of the present disclosure (e.g., the embodiments of Figs. 1-3) is that the gas turbine and the heating vessel arrangement are connected together such that introduction of outside air into the heating vessel arrangement is precluded and the heating vessel arrangement preferably receives the exhaust gases directly from the gas turbine. In certain embodiments, it is preferred that 100% of the gas turbine exhaust gases are passed into at least a first heating vessel and, for most efficient operation, preferably without passing through any intervening heat exchanger, silencer or other equipment in order that the first heating vessel receives the maximum heating from the gas turbine exhaust. But, it is recognized that excess exhaust gases not needed for the heating vessel operation can be diverted to provide heat required in other steps in the systems or in other nearby operations, hi certain embodiments, the exhaust stream entering the heating vessel has a relatively low level of excess oxygen and the heating vessel preferably does not use an exposed flame. Precluding outside air induction into the heating vessel, the absence of exposed flame and operation at the temperatures set forth herein prevents significant oxidation of the waste material feedstock in the heating vessel and also increases heating efficiency. In other embodiments of the present disclosure, it may be desired that air or oxygen be introduced in controlled quantities or ratios to provide a desired oxidation or chemical conversion of the waste material feedstock in the heating vessel. In certain embodiments, waste material feedstock (e.g., oil sand waste material feedstock) fed into heating vessel arrangements of the type disclosed herein can have a moisture content of at least 15 %, or at least 20%, or at least 30%, or at least 40%, or at least 50%, or at least 60% or at least 70% or at least 80% by weight water. Higher water contents can facilitate mechanized handling of the raw material and preparing it for use by blending and mixing for uniformity. In certain applications, the waste material feedstock is moved by augers, front end loaders, back hoes, conveyor belts and the like. However, in those and other operations the waste material feedstock may be prepared in the form of a pumpable slurry, where the water content of the waste material feedstock may be over 90%, 95% or even 98%. Systems in accordance with the present disclosure can efficiently and economically process such high water content waste material feedstock to not only recover the solids content in the form of a final product (e.g., clean sand), but to also recover the process water, which can be recycled for process use. Systems disclosed herein can handle high water content waste material feedstocks efficiently and economically due to the fact that excess steam produced can be used downstream, upstream or in other nearby operations. Instead of holding high water content waste material feedstock in large open ponds, as is conventionally done in many oil sand bitumen extraction operations, systems of the type disclosed herein enable holding the oil sand waste material in enclosures or tanks for essentially immediate processing, which can eliminate the air pollution, odor and environmental problems associated with open ponds. In some cases it may be desirable for economic operation reasons to mechanically separate part of the water from high- water content waste materials, e.g., by centrifuges, filters or presses, before processing the waste material in heating arrangements of the type described herein. Such separated water can be recycled for use as disclosed above.

The term "gas turbine" is used herein to mean and include any turbine engine having a compressor turbine stage, a combustion zone and an exhaust turbine stage that is capable of producing exhaust gas temperatures of at least 500 °F, preferably at least about 700 °F, more preferably at least about 900 °F and most preferably greater than about 1,000 °F. Gas turbines are the heat source preferred for use in systems disclosed herein because of their efficient operation and high heat output. The gas turbine generator is further preferred due to the production of energy by the generator, which energy can be utilized or sold to improve the economics of the operation of the system of this invention. The generator will typically be an electric generator due to the convenience and economic benefit of using and/or selling the electricity produced. However, the generator can be any other type of energy generator desired, such as a hydraulic pump or power pack that can drive hydraulic motors on pumps, augers, conveyors and other types of equipment. The heat requirements and the system economics will determine whether a gas turbine or gas turbine generator is used. If it is desired to have higher temperature exhaust gases and higher heat output from a given smaller size gas turbine, it may be desired to use a gas turbine instead of a similar size gas turbine generator. Compared to the gas turbine, the gas turbine generator further expands and cools the exhaust gases in absorbing energy to drive the generator, where in a gas turbine that energy is contained in higher temperature gases available for use in the heating vessel arrangements of the type disclosed herein. This can be an option when it is economically more important in the practice to have small (e.g., truckable) high temperature units than to have the revenue stream or economic benefit of the electricity or other energy production by the gas turbine.

Turbines or turbine generators useful in systems of the type described herein can be fueled from any available source with any suitable fuel for the particular turbine. The preferred and conventional fuels are sweet natural gas, diesel, kerosene and jet fuel because the gas turbines are designed to run most efficiently on good quality fuels of these types and because of their common availability, particularly at remote operations, where the units of this disclosure may be located. However, other fuels that can be used to fuel the turbine include methane, propane, butane, hydrogen and biogas and bioliquid fuels (such as methane, oils, diesel and ethanol).

Examples of commercially available gas turbines and gas turbine generators useful in systems of the type disclosed herein include the following (rated megawatt (MW) outputs are approximate):

Rolls Royce Gas Turbine Engines Allison 501-KB5, -KB5S or -KB7 having a standard condition rated output of 3.9 MW

European Gas Turbines Tornado having rated output of 7.0 MW

Solar Mars 90 having rated output of 9.4 MW and Solar Mars 100 having rated output of 10.7 MW

Solar Tarus 60 having rated output of 5.5 MW and Solar Tarus 70 having rated output of 7.5 MW.

For a nominal product output capacity of 2.5 metric tons/hr. (2,500 kg/hr) a gas turbine generator size of about 4 MW can be used, depending on the heat insulation and heat recovery efficiencies designed into the overall system. For small single semitrailer or truck systems, the units may be scaled smaller. For smaller product output systems, such as an 0.3 metric ton/hr product output, small gas turbines, such as Solar Saturn 0.8 MW, Solar Spartan 0.2 MW or Capstone 0.5 MW or 0.3 MW generators, can be used depending on system efficiencies and required heat input ranges. It will be recognized that systems according to this disclosure can also be designed to utilize the exhaust gas heat from reciprocating engines, such as gasoline or diesel generators. In certain embodiments, all of the air conveyed by the compressor turbine of the gas turbine is directed to the combustion chamber. In certain other embodiments, the exhaust gas from the combustion chamber of the gas turbine is not mixed with air that by-passes the combustion chamber.

In certain embodiments, heating vessel arrangements employed in systems of the type described herein can be any type or configuration that is suitable for drying and treating waste material feedstock (e.g., oil sand waster material feedstock) and that can be adapted for receiving the gas turbine exhaust gases and receiving the waste material feedstock without allowing a significant amount of outside air to enter the heating chamber/chambers of the heating arrangement where the exhaust gases contact the waste material feedstock. The objective of this design of the gas turbine exhaust connection to the heating vessel arrangement is to preclude any significant outside air from entering the heating vessel arrangement to help prevent significant oxidation of the waste material feedstock. In other embodiments, alternate sources of hot gases other than a gas turbine can be used and connected to the heating vessel arrangement, such as the exhaust from conventional oil or gas burners and reciprocating engines, provided they are operated at conventional combustion ratio conditions having relatively low free oxygen in the exhaust and are connected to the heating vessel arrangement in a fashion that precludes significant outside air from entering the heating vessel arrangement in order to preclude significant oxidation of the feedstock. Of course, such an alternate or additional source of hot gases can optionally be connected to the heating vessel arrangement and used to supplement the exhaust gases output of the gas turbine to provide additional heat input capacity for the heating vessel arrangement if needed for start up, shut down or surge load conditions or for backup in the event the gas turbine goes offline.

It will be recognized that in some operations, not all outside air can be excluded and oxidation of the waste material feedstock cannot be completely precluded, primarily because of the air present in and entrained in the waste material feedstock, the air dissolved in the moisture present in the waste material feedstock and some excess oxygen that may be present in the turbine exhaust gases. Therefore, the terms as used herein which refer to "preclude introduction of air," "without significant oxidation," and the like, are used in the above operational context and with the recognition and intended meaning that the air or oxygen entering the system as part of the waste material feedstock or exhaust gases or produced in the thermal conversion process is not intended to be precluded and that the oxidation that may occur as a result of that air entering the system with the waste material feedstock is not intended to be prevented. However, such a level of oxidation is not considered significant within the scope, context and practice of this invention or the meanings of those terms as used herein. Exclusion of outside air is also preferred for economic efficiency as well, because heating excess or outside air along with heating the waste material feedstock reduces the efficiency of the process. The types of heating vessels that can be used in heating vessel arrangements in accordance with the present disclosure are, for example, the following:

Rotary drum with or without internal scrapers, agitation plates and/or paddles Stationary "porcupine" drum dryer with or without scrapers and/or agitator plates and/or paddles

Triple pass stepped drying cylinder or rotary drum heating vessel systems with or without scrapers and/or agitator plates and/or paddles

Rotary drum heating vessel systems with or without steam tubes and with or without scrapers and/or agitator plates and/or paddles

Turbo-dryer or turbulizer systems

Conveyor dryer systems with or without scrapers and/or agitator plates and/or paddles

Indirect or direct contact dryer systems with or without scrapers and/or agitator plates and/or paddles

Tray dryers

Fluid bed dryers

Evaporator systems Baking ovens

Examples of commercially available heating vessels useful in or that can be adapted for use with heating vessel arrangements of the type described herein include: Scott AST Dryer Systems

Simon Dryer Ltd. Drum dryers

Wyssmont Turbo Dryer systems

Duske Engineering Co., Inc.

Energy Unlimited drying systems The Onix Corporation dehydration systems

International Technology Systems, Inc. direct or indirect dryer systems

Pulse Drying Systems, Inc.

MEC Company dryer systems. Further examples of heating vessels useful in or that can be adapted for use in this invention are disclosed in U.S. Pat. No. 5,746,006 to Duske et al. and U.S. Pat. No. 5,570,517 and U.S. Pat. No. 6,367,163 to Luker, the disclosures of which are incorporated herein by reference in their entirety.

In certain embodiments, the heating vessel arrangement need not provide direct contact of the turbine exhaust gases or other heat source and the waste material feedstock, but can provide indirect heating of the waste material feedstock to achieve the drying and/or thermal treatment/conversion/alteration desired according to this invention. The heating vessel arrangements can includes one or more heating vessels lined with appropriate material to prevent or reduce corrosion, erosion or excessive wear. It will be recognized that the systems can be adapted to perform various functions in various configurations in a particular installation or operation. For example, two heating vessels can be operated in series where a high water content feedstock is dried in the first heating vessel then the output from the first heating vessel is thermally treated in the second heating vessel to achieve the desired treatment. In such an arrangement, the exhaust gases can be supplied from a single gas turbine exhaust split between the two heating vessels, or can be supplied by two separate gas turbines. From this example it can be seen that the processes, apparatus and systems of this disclosure can be adapted to operate various equipment components in series or in parallel to perform various processing functions desired to achieve the effective and economic operation thereof.

In certain embodiments, heating vessel arrangements of the type disclosed herein include a heating vessel that also functions as the silencer for the gas turbine or other engine providing the hot exhaust gases. It is well known that gas turbines can produce a high level of noise impact on the nearby environment. Stationary gas turbines used for electric power production or other purposes are usually required by local, state and federal regulations to have silencers installed to muffle the noise of the exhaust of the gas turbine to acceptable levels. Such silencers have the economic disadvantages of cost and creating back pressure on the gas turbine exhaust, which reduces the efficiency of the gas turbine operation. One advantage of systems disclosed herein, due to the connection between the gas turbine exhaust and the heating vessel preferably being closed to outside air, is that the heating vessel functions effectively as a silencer for the gas turbine. This is at least in part a result of the internal configuration construction of the heating vessel acting in combination with the presence of the high water content waste material feedstock, which combination is effective in absorbing and muffling the gas turbine exhaust noise. This is also due to the downstream end of the heating vessel also being closed to the atmosphere, because the steam and off gases from the heating vessel are collected for condensation, cleaning, recycling and for heat recovery in the downstream processing in a closed system before being vented to the atmosphere. It will be apparent to one skilled in the art that capability for venting at various points in the process and the equipment system may be desirable to accommodate startup, shutdown, upset or feedstock variability, but will normally be operated as a closed system having only final product output and clean gas venting. The turbine exhaust can optionally be partially or temporarily wholly diverted to other downstream units, bypassing the heating vessel, when needed for supplemental heat in other process units or for startup, shut-down or upset. hi certain embodiments of the present disclosure, the steam and off gases can be pulled from the discharge end of the heating vessel arrangement by an appropriate fan, vent blower, etc., to provide a reduced pressure at the upstream entrance of the heating vessel arrangement, thereby reducing the back pressure on the turbine exhaust. This increases the efficiency of operation of the gas turbine and is made possible because the connection between the gas turbine exhaust and the heating vessel is not open to outside air. It will be understood that the commercial system design may include a vent or even a conventional silencer connected by tee or other configuration into the connection between the gas turbine exhaust and the heating vessel for use during startup, shut down or upset operation, but would not be employed in the normal operating configuration for the process and apparatus of this invention as described above. To achieve best efficiency, it is preferred that the connection between the gas turbine exhaust and the heating vessel inlet have no obstructions in order to deliver the exhaust gases to the heating vessel with a minimum of heat and energy loss between the gas turbine and the heating vessel. It will also be recognized from this disclosure, that the operation of a gas turbine generator will preferably be controlled for optimal efficiency or economics for the waste material feedstock drying, thermal conversion, chemical alteration and other processing needs, which may not be the optimal or best gas turbine operating conditions for electricity production. The electricity production is a cost recovery revenue stream for the system, but the overall economics of the operation of this invention may be better under gas turbine operating conditions that favor optimum exhaust heat output for efficient heating vessel operation and downstream production of products having desired properties and disfavor electricity production, Determination of such operating conditions for a particular installation of this invention will be apparent to one skilled in the art following the teachings herein.

The operating conditions and procedures for the heating vessel arrangement will be apparent to one skilled in the art following the teachings herein of the present disclosure. The typical turbine exhaust gas temperature entering the heating vessels forming part of the heating vessel arrangement may be in the range of about 500 °F to about 1,500 °F, depending on moisture and other content of the waste material feedstock. The temperature and flow rate of the gas entering the heating vessel will depend in part on the moisture content and other properties of the waste material feedstock. Higher moisture content will generally require higher inlet gas temperatures to reduce the moisture content. It is believed that an additional efficiency is achieved in the systems of the present invention where high moisture content waste material feedstock is contacted with high temperature gases. Such contact causes the formation, sometimes instantly, of superheated steam as the moisture comes out of the waste material feedstock, then that superheated steam heats and drives the moisture out of adjacent waste material feedstock.

Preferably, the hot exhaust gas provided to a heating vessel used to volatize hydrocarbons has a temperature greater than 900°F, or greater than l,000°F, or greater than 1250 ⁰F, or greater than 1500 °F, or in the range of about 1 ,000 to l,500°F. In a preferred embodiment, oil sand waste material feedstock within the heating vessel arrangement is heated to a temperature equal to or greater than a volatilization temperature of hydrocarbons (e.g., bitumen) contained within oil sand waste material feedstock (e.g., 977⁰F). The preceding embodiments are intended to illustrate without limitation the utility and scope of the present disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made to the embodiments described above without departing from the true spirit and scope of the disclosure.

Claims

WHAT IS CLAIMED IS:

1. A method for processing oil sand waste material feedstock comprising: operating a gas turbine generator to produce electricity and exhaust gases; and removing at least some moisture from the oil sand waste material feedstock by using heat from the exhaust gases produced by the gas turbine generator.

2. The method of claim 1, wherein the exhaust gases directly contact the oil sand waste material feedstock to remove the moisture from the oil sand waste material.

3. The method of claim 2, wherein the exhaust gases directly contact the oil sand waste material feedstock within a heating vessel, and wherein outside air is substantially precluded from entering the heating vessel.

4. The method of claim 3, wherein the exhaust gases have a temperature greater than 1000 ⁰F when entering the heating vessel.

5. The method of claim 1, wherein the oil sand waste material feedstock is produced from a process in which heated water is mixed with oil sand, and wherein waste heat from the gas turbine generator is used to at least partially heat the heated water.

6. The method of claim 5, wherein water removed from the oil sand waste material feedstock is included in the heated water mixed with the oil sand.

7. The method of claim 1 , wherein the oil sand waste material feedstock is stored in a settling pond before the moisture is removed from the oil sand waste material feedstock using heat from the exhaust gases produced by the gas turbine generator.

8. The method of claim 1, wherein the oil sand waste material feedstock is at least partially de-watered before the moisture is removed from the oil sand waste material feedstock using heat from the exhaust gases produced by the gas turbine generator.

9. The method of claim 1 , wherein the oil sand waste material feedstock is not stored in an open settling pond before the moisture is removed from the oil sand waste material feedstock using heat from the exhaust gases produced by the gas turbine generator.

10. The method of claim 9, wherein the oil sand waste material feedstock is at least partially de-watered before the moisture is removed from the oil sand waste material feedstock using heat from the exhaust gases produced by the gas turbine generator.

11. The method of claim 1 , wherein the heat from the exhaust gases produced by the gas turbine generator is used to remove at least a portion of a contaminant from the oil sand waste material feedstock.

12. The method of claim 11 , wherein the contaminant is volatilized by the heat from the exhaust gases.

13. The method of claim 12, wherein the contaminant includes a hydrocarbon.

14. The method of claim 13, wherein the contaminant includes bitumen.

15. The method of claim 11 , wherein after the oil sand waste material feedstock has been heated, the remaining material is substantially non-leachable.

16. The method of claim 1 , wherein the moisture is initially removed from the oil sand waste material feedstock at a first heating vessel, and the contaminant is removed from the oil sand waste material feedstock at a second heating vessel after the oil sand waste material feedstock has been dried at the first heating vessel.

17. The method of claim 1, wherein a single one of the gas turbine generator provides the exhaust gases for heating the first and second heating vessels.

18. The method of claim 17, wherein the exhaust gases first pass through the second heating vessel and later pass through the first heating vessel.

19. A method for processing oil sand waste material feedstock comprising: operating a gas turbine generator to produce electricity and exhaust gases; and removing at least a portion of a contaminant from the oil sand waste material feedstock by using heat from the exhaust gases produced by the gas turbine generator.

20. The method of claim 19, wherein the exhaust gases directly contact the oil sand waste material feedstock to remove the contaminant from the oil sand waste material.

21. The method of claim 20, wherein the exhaust gases directly contact the oil sand waste material feedstock within a heating vessel, and wherein outside air is substantially precluded from entering the heating vessel.

22. The method of claim 21 , wherein the exhaust gases have a temperature greater than 1000 °F when entering the heating vessel.

23. The method of claim 19, wherein the contaminant is volatilized by the heat from the exhaust gases.

24. The method of claim 23, wherein the contaminant includes a hydrocarbon.

25. The method of claim 24, wherein the contaminant includes bitumen.

26. An oil sand processing system comprising: a hot water source for supplying hot water that is mixed with oil sand to form a hot water slurry; a bitumen extraction plant that receives the hot water slurry and extracts bitumen from the hot water slurry; a heating vessel arrangement that heats oil sand water material feedstock produced at the bitumen extraction plant; and a gas turbine generator that produces electricity and also produces exhaust gases used to heat the heating vessel arrangement.

27. The oil sand processing system of claim 26, wherein the exhaust gases directly contact the oil sand waste material feedstock within the heating vessel arrangement, and wherein the system further comprises a solids separator positioned downstream from the heating vessel arrangement for separating sand that exits the heating vessel from a gas stream that exits the heating vessel arrangement.

28. The oil sand processing system of claim 26, further comprising a gas separating arrangement that separates volatilized hydrocarbons and water vapor from a gas stream exiting the heating vessel arrangement.

29. The oil sand processing system of claim 28, wherein the water vapor is condensed and added to the hot water that is mixed with oil sand to form the hot water slurry.

30. The oil sand processing system of claim 26, further comprising a heat exchanger that uses waste heat from the gas turbine generator to pre-heat the hot water that is mixed with oil sand to form the hot water slurry.

31. A method for treating tailings generated from mining operations, drilling operations and/or oil extraction operations, the method comprising: operating a gas turbine generator to produce electricity and exhaust gases; treating the tailings by heating the tailings with the exhaust gases.

32. The method of claim 31 , wherein the tailings are provided from a tailings pond.

33. A method for treating a tailings pond comprising: operating a gas turbine generator to produce electricity and exhaust gases; drawing water containing tailings from the tailings pond; and directly contacting the water containing the tailings with the exhaust gases.

34. The method of claim 33, wherein the water is drawn from a middle layer of the tailings pond.