CA2715619A1

CA2715619A1 - Steam drive direct contact steam generation

Info

Publication number: CA2715619A1
Application number: CA2715619A
Authority: CA
Inventors: Maoz Betzer-Zilevitch
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-11-12
Filing date: 2010-09-13
Publication date: 2011-05-12
Also published as: US20120279903A1

Abstract

The present invention is a system and method for steam production for extraction of heavy bitumen. The method includes generating steam, mixing the steam with water containing solids and organics, separating solids, and injecting the steam through an injection well or using it above ground for oil recovery. The system includes a steam drive direct contact steam generator. The water feed of the present invention can be water separated from produced oil and/or low quality water salvaged from industrial plants, such as refineries and tailings as make-up water.

Description

STEAM DRIVE DIRECT CONTACT STEAM GENERATION
BACKGROUND OF THE INVENTION

1. Field of the Invention [01] This application relates to a system and method for producing steam from contaminated water feed for Enhanced Oil Recovery (EOR). This invention relates to processes for directly using steam energy, preferably superheated dry steam, for generating additional steam from contaminated water by direct contact, and using this produced steam for underground injection for Enhanced Oil Recovery. The high pressure drive steam is generated using commercially available, non-direct steam boiler, co-gen, OTSG or any available steam generation system.
The contaminates, like suspended or dissolved solids within the low quality water feed, can be removed in a stable solid (former Liquid Discharge) system. The system can be integrated with combustion gas fired DCSG (Direct Contact Steam Generator) for consuming liquid waste streams.

[02] The injection of steam into heavy oil formations was proven to be an effective method for FOR and it is the only method currently used commercially for recovery of bitumen from deep underground oilsand formations in Canada. It is known that FOR can be achieved where combustion gases, mainly C02, are injected into the formation, possibly with the use of DCSG as described in my previous applications. The problem is that oil producers are reluctant to implement significant changes to their facilities, especially if they include changing the composition of the injected gas to the underground formation and the risk of corrosion in the carbon steel pipes due to the presence of the C02. Another option to fulfill this requirement and generate steam from low grade produced water with ZLD is to operate the DCSG with steam instead of a combustion gas mixture that includes, in addition to steam, other gases like nitrogen, carbon dioxide, carbon monoxide and other gases. The driving steam is generated by a commercially available non-direct steam generation facility.
The driving steam is directly used to transfer liquid water into steam and solid waste. In FOR facilities most of the water required for steam generation is recovered from the produced bitumen-water emulsion. The produced water has to be extensively treated to remove the oil remains that can damage the boilers.
This process is expensive and consumes large amount of chemicals. The SD-DCSG (Steam Drive - Direct Contact Steam Generator) can consume the contaminated water feed for generating steam. The SD-DCSG can be stand alone system or can be integrated with combustion gas DCSG as described in this application.

[03] The steam for the SD-DCSG can be provided directly from a power station.
The most suitable steam will be the medium pressure, super-heated steam as typically fed to the second or third stage of steam turbine. A cost efficient, hence effective system will be to employ a high pressure, single stage steam turbine to generate electricity. The discharge steam from the turbine, at a lower pressure, can be recycled back to the boiler re-heater to generate a super heated steam which is effective as a driving steam. Due to the fact that the first stage turbine, which is the smallest size turbine, produces most of the power (due to a higher pressure), the cost per Megawatt of the steam turbine will be relatively low. The efficiency of the system will not be affected as the superheated steam will be used to drive the SD-DCSG directly and generating injection steam for enhanced oil recovery unit with Zero Liquid Discharge (ZLD). A ZLD facility is more environmentally friendly compared to a system that generates reject water and sludge.

[04] The definition of "Steam Drive - Direct Contact Steam Generation" (SD-DCSG) is that steam is used to generate additional steam from direct contact heat transfer between the liquid water and the combustion gas. This is accomplished through the direct mixing of the two flows (the water and the steam gases). In the SD-DCSG, the driving steam pressure is similar to the produced steam pressure and the produced steam is a mixture of the two.

[05] The driving steam is generated in a Non-Direct Steam Generator (like a steam boiler with a steam drum and a mud drum) or "Once Through Steam Generator" (OTSG) COGEN that uses the heat from a gas turbine to generate steam or any other available design. The heat transfer and combustion gases are not mixed and the heat transfer is done through a wall (typically a metal wall), where the pressure of the generated steam is higher than the pressure of the combustion. This allows for the use of atmospheric combustion pressure. The product is pure steam (or a steam and water mixture, as in the case of the OTSG) without combustion gases.

[06] There are patents and disclosures issued in the field of the present invention. US patent No. 6,536,523 issued to Kresnyak et at. on March 25, 2003 describes the use of the blow-down heat as the heat source for water distillation of de-oiled produced water in a single stage MVC water distillation unit. The concentrated blow-down from the distillation unit can be treated in a crystallizer to generate solid waste.

[07] US Patent application 12/702,004 filed by Minnich et al. and published on August 12, 2010 describes a heat exchanger that operates on steam for generating steam in an indirect way from low quality produced water that contains impurities. In this disclosure, steam is used indirectly to heat the produced water that include contaminates. By using steam as the heat transfer medium the direct exposure of the low quality water heat exchanger to fire and radiation is prevented, thus there will be no damage due to the redaction of the heat transfer. The concentrated brine is collected and delivered to disposal or to multi stage evaporator to recover most of the water and generates a ZLD (Zero Liquid discharge) system. The heat transfer surfaces between the steam and the produced water will have to be clean or the produced water will have to be treated. The concentrated brine, possibly with organics, will be treated in a low pressure, low temperature evaporator to increase their concentration; the higher the concentration is, the lower the temperature. In my application, due to the direct approach of the heat transfer, the system in ZLD with the highest concentration, possibly up to 100% liquid recovery while generating solid waste, is at the first stage at the higher temperature due to the direct mixture with the superheated dry steam that converts the liquid into gas and solids.

[08] US patent No. 7,591,309 issued to Minnich et al. on September 22, 2009 describes the use of steam for operating a pressurized evaporation facility where the pressurized vapor steam is injected into underground formation for EOR. The steam heats the brine water which is boiled to generate additional steam. To prevent the generation of solids in the pressurized evaporator, the internal surfaces are kept wet by liquid water and the water is pre-treated to prevent solid build up. The concentrated brine is discharged for disposal or for further treatment in a separate facility to achieve a ZLD system. To achieve ZLD, the brine evaporates in a series of low pressure evaporators (Multi Effect Evaporator).

[09] US patent No. 6,733636, issued to Heins on May 11, 2004, describes a produced water treatment process with a vertical MVC evaporator.

[10] US Patent No. 7,578,354, issued to Minnich et al. on August 25, 2009, describes the use of MED for generating steam for injecting into an underground formation.

[11] US Patent No. 7,591,311, issued to Minnich et al. on September 22, 2009, describes evaporating water to produce distilled water and brine discharge, feeding the distilled water to a boiler, and injecting the boiler blow-down water from the boiler to the produced steam. The solids and possibly volatile organic remains are carried with the steam to the underground oil formation. The concentrated brine is discharged in liquid form.

[12] This invention's method and system for producing steam for extraction of heavy bitumen includes the steps as described in the patent figures.

[13] The advantage and objective of the present invention are described in the patent application and in the attached figures.

[14] These and other objectives and advantages of the present invention will become apparent from a reading of the attached specifications and appended claims.

SUMMARY OF THE INVENTION

[15] The method and system of the present invention for steam production for extraction of heavy bitumen by injecting the steam to an underground formation or by using it as part of an above ground oil extraction facility includes the following steps: (1) Generating a super heated steam stream.
The steam is generated by a commercially available non-direct steam generation facility , possibly as part of a power plant facility; (2) Using the generated steam as the hot gas to operate a DCSG (Direct Contact Steam Generator); (3) Mixing the super heated steam gas with liquid water with significant levels of solids, oil contamination and other contaminate; (4) Directly converting liquid phase water into gas phase steam; (5) Removing the solid contaminates that were supplied with the water for disposal or further treatment; (6) Using the generated steam for EOR, possibly by injecting the produced steam into an underground oil formation through SAGD or CSS steam injection well.

[16] In another embodiment, the invention can include the following steps: (1) Generating a super heated steam stream. The steam is generated by heating a steam stream in non-direct heat exchanger; (2) Using the generated steam as the hot gas to operate a DCSG
(Direct Contact Steam Generator); (3) Mixing the super heated steam gas with liquid water with significant levels of solids, oil contamination and other contaminates; (4) Directly converting liquid phase water into gas phase steam;
(5) Removing the solid contaminates that were supplied with the water for disposal or further treatment; (6) Recycling a portion of the generated steam back to the heating process of (1) to be used as hot gas operating the DCSG.

[17] In another embodiment, part of the generating steam is condensed and used to wash the produced steam from solid particles in a wet scrubber. Chemicals can be added to the liquid water to remove contaminates. A portion of the liquid water is recycled back and mixed with the superheated steam to transfer it into gas and solids. A portion from the scrubbed saturated steam flow can be recycled and heated to generate a super heated "dry" steam flow to drive the SD-DCSG and change the liquid flow into steam.

[18] In another embodiment, the scrubbed saturated steam, after the solids were removed, can be condensed to generate contaminate free liquid water, at a saturated temperature and pressure.
The liquid water can be pumped and fed into a commercially available non-direct steam boiler for generating super heated steam to drive the SD-DCSG for transferring the liquid contaminated water into gas and solids.

[19] In another embodiment, the SD-DCSG is integrated with DCSG that uses combustion gases as the heat source. In that embodiment, the discharge from the SD-DCSG
can be in a liquid form and it can be used as the water source for the combustion gas driven DCSG.

[20] The present invention can be used to treat contaminated water by SD-DCSG
in different industries like the power industry or chemical industry where there is a need to recover the water from contaminated water stream to generate steam with zero liquid discharge.

[21] The system and method different aspects of the present invention are clear from the following figures.

DETAILED DESCRIPTION OFTHE DRAWINGS

[22] FIGURES 1, and 1A show the conceptual flowchart of the method and the system.

[23] FIGURE 2 shows a block diagram of the invention. Flow 9 is superheated steam. The steam pressure can be from 1 to 150 bar and the temperature can be between 150C and 600C. The steam flows to enclosure 11 which is a SD-DCSG. Contaminated produced water 7, possibly with organic contaminates, suspended and dissolved solids, is also injected into enclosure 11 as the water source for generating steam. The water 7 evaporates and is transferred into steam. The remaining solids 12 are removed from the system. The generated steam 8 is at the same pressure as that of the drive steam 9 but at a lower temperature as a portion of its energy was used to drive the liquid water 7 through a phase change. The generated steam is also at a temperature that is close to the saturated temperature of the steam at the pressure inside enclosure 11. The produce steam can be further treated 13 to remove carry-on solids, reducing its pressure and possibly removing additional chemical contaminates.
Then the produced steam is injected into an injection well for EOR.

[24] FIGURE 2A shows a schematic of a vertical SD-DCSG. Dry steam 9 is injected to vessel 11 at its lower section. At the upper section, water 7 isinjected 3 directly into the up-flow stream of dry steam. The water evaporates and is converted to steam at lower temperature but at the same pressure.
The contaminates that were carried on with the water are turned into solids and possibly gas (if the water includes hydrocarbons like naphtha). The produced gas, mainly steam, is discharged from the SD-DCSG at the top. To prevent carried-on water droplets, demister packing 5 can be used at the top of SD-DCSG enclosure 11. The solids 12 are removed from the system from the bottom 1 of the vertical enclosure where they can be disposed of or further treated.

[25] FIGURE 2B shows a block diagram of the invention. This figure is similar to Figure 2 but with an additional solids removal system as described in Block 15. Block 15 can include any commercially available Solid - Gas separation unit. In this particular figure, cyclone separator 19 and electrostatic separation are presented. High temperature filters, that can withstand the steam temperature, possibly with a back-pressure cleanup system, can be used as well. The steam flow leaving the SD-DCSG can include solids from the contaminate water 7. A portion of the solids 12 can be recovered in a dry or wet form from the bottom of the steam generation enclosure 11. The carry-on solids 14 can be recovered from the gas flow 8 in a dry form for disposal or for further treatment.

[26] FIGURE 2C is another embodiment of a reaction chamber apparatus of a high-pressure steam drive direct contact steam generator of the present invention. A similar structure can be used with DCSG that uses combustion gas as the heat source to convert the liquid water into steam. A
counter-flow horizontally-sloped pressure drum 10 is partially filled with chains 11 that are free to move inside the drum and are internally connected to the drum wall. A parallel flow design can be used as well. The chains increase the heat transfer and removes solids build-up. Any other design that includes internal embodiments that are free to move or moving with the rotating enclosure and lifting solids and liquids to enhance their mixture with the flowing gas can be used as well. The drum 10 is a pressure vessel and is continually rotating, or rotating at intervals. At a low point of the sloped vessel 10, hot dry steam 8 is generated by a separate unit, like the pressurized boiler (not shown), and is injected into the enclosure 8. The boiler is a commercially available boiler that can burn any available fuel like coal, coke, or hydrocarbons such as untreated heavy low quality crude oil, VR (vacuum residuals), asphaltin, coke, or any other available carbon or hydrocarbon fuel. The pressure inside the rotating drum can vary between lbar and 100bar, according to the oil underground formation. The vessel is partially filled with chains 10 that are internally connected to the vessel wall and are free to move. The chains 10 provide an exposed regenerated surface area that works as a heat exchanger and continually cleans the insides of the rotating vessel. The injected steam temperature can be any temperature that the boiler can supply, typically in the range of 200C and 800C. Low quality water, like mature tailing pond water, rich with solids and other contaminants (like oil based organics) or contaminated water from the produced water treatment process are injected into the opposite higher side of the vessel at section 4 where they are mixed with the driving dry steam and converted into steam at a lower temperature. This heat exchange and phase exchange continues at section 3 where the heavy liquids and solids move downwards, directly opposite to the driving steam flow. The driving steam injected at section 2, which is located at the lower side of the sloped vessel, moves upwards while converting liquid water to gas. The heat exchange between the dry driving steam to the liquids is increased by the use of chains that maintain close contact, both with the hot steam and with the liquids at the bottom of the rotating vessel. The amount of injected water is controlled to produce steam in which the dissolved solids become dry or high solids concentration slurry and most of the liquids become gases.
Additional chemical materials can be added to the reaction, preferably with any injected water. The rotational movement regenerates the internal surface area by mobilizing the solids to the discharged point.
The heat transfer in section 3 is sufficient to provide a homogenous mixture of gas steam and ground - up solids or high viscosity slurry. Most of the remaining liquid transitions to gas and the remaining solids are moved to a discharge point 7 at the lower internal section of the rotating vessel near the rotating pressurized drum 10 wall.
The solids or slurry are released from the vessel 10 at a high temperature and pressure. They undergo further processing, such as separation and disposal.

[27] FIGURE 3 is an illustration of one embodiment of the present invention without using an external source for the driving steam. SD-DCSG 30 includes a hot and dry steam injection 36. The steam is flowing upwards where low quality water 34 is injected to the up flow steam. At least a portion of the injected water is converted into steam at a lower temperature and at the same pressure as the dry driving steam 36. The generated steam can be saturated ("wet") steam at a lower temperature than the driving steam. A portion of the generated steam 32 is recycled through compressing device 39. The compression is only designed to create the steam flow through heat exchanger 38 and create the up flow in the SD-DCSG 30. The compressing unit 39 can be a mechanical rotating compressor. Another option is to use high pressure steam 40 and inject it through ejectors to generate the required over pressure and flow in line 36. The produced low pressure steam flows to heat exchanger 38 where additional heat is added to the recycled steam flow 32 to generate a heated "dry" steam 36. This steam is used to drive the SD-DCSG as it is injected into its lower section 30 and the excess heat energy is used to evaporate the injected water and generate additional steam 31. The heat exchanger 38 is not a boiler as the feed is in gas phase (steam). The produced steam 31 or just the recycled produced steam 32 can be cleaned from solids carried with the steam gas by an additional commercially available system (not shown). The system can include solid removal; this heat exchanger can be any commercially available design. The heat source can be fuel combustion where the heat transfer can be radiation, convection or both. Another possibility can be to use the design of the re-heat heat exchanger typically used in power stations to heat the medium / low pressure steam after it is released from the high pressure stages of the steam turbine.

[28] FIGURE 3A is an illustration of one embodiment of the present invention.
It is similar to Figure 3 with the use of a rotating SD-DCSG. The driving superheated ("dry") steam 36 is injected into rotating pressurized enclosure 30. The rotating SD-DCSG enclosure consumes liquid water 34, possibly with solid and organic contaminations, and generates lower temperature steam 31 and solid waste 35 that can be disposed in a landfill and support traffic. The rotating SD-DCSG
30 is described in Figure 2C.

[29] FIGURE 4 is an illustration of one embodiment of the present invention, where the generated steam 44 is saturated and is washed by saturated water in a wet scrubber 40 where additional steam is generated. BLOCK 1 includes the system as described in FIGURE 3 where BLOCK 32 can include solid removal as means to remove solid particles from the gas (steam) flow. BLOCK 3 generates steam 33 and stable waste 35. The generated steam 33 can contain carry-on solid particles and contaminates that might create problems of corrosion or solids build ups in the high temperature heat exchanger. One way to remove the solid contaminates is by a commercially available solid-gas separation unit, as described in Figure 2B or with any other prior art solids removal method. However, there is an advantage to wet scrubbing of solids and possible other gas contaminates. To improve the removal of the solids and other contaminates, the steam 33 is directed to a wet scrubber. In one embodiment, the wet scrubber generates the liquid water for its operation.
This is done by an internal heat exchanger that recovers heat from the steam and generates condensate water. The condensate liquid water is used for scrubbing the flowing steam in vessel 40. The condensate is recycled 41 and used to wash the steam and is used as a means to improve the heat transfer. Low quality water from the oil-water separation process, fine tailing water from tailing pond or from any other source is pre-heated through heat exchanger 42 while recovering heat from the produced steam 34 generated by the SD-DCSG 30. The condensate is recycled in the wet scrubber to wash the steam.
Additional chemicals can be added to the condensate to remove gas contaminates. A portion of the condensate with the solids and other contaminates 43 is removed from vessel 40 to maintain the contamination concentration of the condensate constant. Additional low quality water 47A can be added to the SD-DCSG without pre-heating as to prevent excessive cooling of the produced steam 33 and the generation of excessive condensate. The generated steam after going through the wet scrubber is clean and saturated ("wet") steam. A portion of the clean steam 45 is directed through trough heat exchange 38 to generate "dry"
steam to drive the SD-DCSG 30 with sufficient thermal energy to convert the low quality water feed 34 into steam. The flow through the heat exchanger and inside the vessel 30 is generated by any suitable commercial unit that can be driven by mechanical energy or a jet energy driven compression unit. The produced clean saturated steam 46 can be injected into an underground reservoir, like SAGD, for oil recovery, it can also be used for heating process water for tar separation or for any other process that consumes steam.

[30] FIGURE 5 is a schematic diagram of one embodiment of the invention that generates wet scrubbed, clean saturated steam. BLOCK 1 includes a SD-DCSG 30 as previously described. The generated steam 31 can be cleaned from solids in commercially unit 32, previously described. Low quality water 34, like MFT (Mature Fine Tailings), produced water or water from any other available source can be injected to the SD-DCSG 30. Solids 35 carried by the water 34 are removed. The SD-DCSG
30 is driven by superheated ("dry") steam that supplies the energy needed for the steam generation process. The dry steam 36 is generated by a commercially available boiler as described in BLOCK 4. BFW
(Boiler Feed Water) 49 is supplied to BLOCK 4 for generating the driving steam. The boiler facility can include an industrial boiler, OTSG, COGEN combined with gas turbine, steam turbine discharge re heater or any other commercially available design that can generate dry steam 36 that can drive the SD-DCSG
30. In the case where the boiler consumes low quality fuel, like petcoke or coal, commercially available flue gas treatment will be used. There is a lot of prior art knowledge as for the facility in BLOCK 4 as it is similar to the facility that is used all over the world for generating electricity. The generated steam from the SD-DCSG 37 is supplied to BLOCK 2 that includes a wet scrubber. The wet scrubber 50 can contain chemicals like ammonia or any other chemical additives to remove contaminates.
The exact chemicals and their concentration will be determined based on the particular contaminates in the low quality water that is used. The contamination levels are much lowerthan in direct fired DCSG where the water is directly exposed to the combustion products as described in my previous patents. Liquid water 48 is injected to the wet scrubber vessel 50 to scrub the contaminates from the up-flowing steam 37. Liquid water 51 that includes the scrubbed solids are removed from vessel 50 and recycled back to the SD-DCSG 30 together with the feed water 34. Depending on the particular feed water quality 34, it can be used in the scrubber. In that case stream 48 and 34 will have the same chemical properties and be from the same source. The scrubbed generated steam 45 generated at BLOCK 2 can be used for extracting and producing of heavy oil or for any other use.

[31] FIGURE 5A is an illustration of one embodiment of the invention where a portion of the driving steam water is internally generated. The embodiment is described in Figure 5 with the following changes: BLOCK 3 was added and connected to BLOCK 2. This block includes a direct contact condenser/
heat exchanger 40 that is designed to generate hot (saturated) boiler feed water 46 and possibly saturated steam 44. The saturated steam 45 from scrubber 50 flows into the lower section of a direct contact heat exchanger / condenser 40 where BFW 42 is injected. From the direct contact during the heat-up of the BFW, additional water will be condensed generating additional BFW 46. A portion of the injected and generated water 48 is used in wet scrubber 50 to remove contamination and is then recycled back to the SD-DCSG 30. The additional condensate, clean BFW quality water 49, is used in BLOCK 4 for generating steam. The condensate is hot at the water or steam saturated temperature in the particle system pressure. Addition hot condensate can be generated and recovered from the system as hot process water for oil recovery or for other uses.

[32] FIGURE 5B is a schematic view of the invention with internal distillation water production for the boiler. The illustration is similar to the process described in Figure 5A with a different BLOCK 3. The low quality water 47 is heated with the saturated clean (wet scrubbed) steam 45 from BLOCK 2 (previously described). The saturated steam 45 condenses on the heat exchanger 42, located inside vessel 40, while generating distilled water 46. A portion of the distilled water 48 is recycled to the wet scrubber vessel 50 where it removes the solids and generates additional wet steam from the partially dry steam generated in the SD-DCSG 30 in BLOCK 1. Additional distilled water 49, possibly after minor treatment and chemical additives (not shown) to bring it to BFW
specifications, is directed to the boiler in BLOCK 4 for generating the driving steam. The system can produce saturated steam 44A or saturated liquid distilled water 44B or both. The produced steam and water are used for oil production and process or for any other use.

[33] FIGURE 5C is a schematic diagram of the method that is similar to Figure 5B but with a different type of SD-DCSG in Block 1. Figure 5C includes a vertical stationary SD-DCSG. The dry driving steam 36 is fed into vessel 30 where the low quality water 34 is fed above it.
Due to excessive heat, the liquid water is converted into steam. The waste discharge at the bottom 35 can be in a liquid or solid form. BLOCKS 2, 3 and 4 are similar to the previous Figure 5B.

[34] FIGURE 6 is a schematic diagram of the present invention which includes a SD-DCSG
and an FOR facility like SAGD for injecting steam underground. BLOCK 1 is a standard commercially available boiler facility. Fuel 1 and oxidizer 2 are combusted in the boiler 3. The combustion heat is recovered through non-direct steam generator for generation of superheated dry steam 9. The combustion gases are released to the atmosphere or for further treatment (like solid particles removal, SOX removal, CO2 recovery etc.). The water that is fed to the boiler, is fed from BLOCK 2 which includes a commercially available boiler treatment facility. The quality of the supplied water is according the particular specifications of the steam generation system in use.
The dry steam is fed to SD-DCSG 10. Additional low quality water 7 is fed into vessel 11 where the liquid water is transferred to steam due to the excess heat in the superheated driving steam 9. The generated steam 8, possibly saturated or close to being saturated steam, is injected into an underground formation through an injection well 16 for EOR. The produced emulsion 13 of water and bitumen is recovered at the production well 15. The produced emulsion is treated using commercially available technology and facilities in BLOCK 2, where the bitumen is recovered and the water is treated for re-use as a BFW. Additional make-up water 14, possibly from water wells or from any other available water source can be added and treated in the water treatment plant. The water treatment plant produces two streams of water - a BFW quality 6 stream as it is currently done to feed the boilers and another stream of contaminated water 7 that can include the chemicals that were used to produced the high quality BFW, oil contaminates, dissolved solid (like salts) and suspended solids (like silica and clay). The low quality flow is fed to the SD-DCSG 10 to generate injection steam.

[35] FIGURE 6A is a schematic flow diagram of the integration between SD-DCSG
and DCSG that uses the combustion gas generated by pressurized boiler. BLOCK 1 includes a DCSG with non-direct heat exchanger boiler as described in my previous applications.
Carbon or hydrocarbon fuel 2 is mixed with an oxidizer that can be air, oxygen or oxygen enriched air 1 and combusted in a pressurized combustor. Low quality water 12 discharged from the SD-DCSG is fed into the combustion unit to recover a portion of the combustion heat and to generate a stream of steam and combustion gas mixture 4. The solid contaminates 18 are removed in a solid or stable slurry form where they can be disposed of. The steam and combustion gas mixture 4 is injected into injection well 17 for EOR. Injection well 17 can be a SAGD "old" injection well where the formation oil is partly recovered and large underground volumes are available, as well as where corrosion problems are not so crucial as the well is approaching the end of its service life. Another preferable option for using the steam and combustion gas mixture is to inject it into a formation that is losing pressure and needs to be pressurized by the injection of addition non-condensable gas, together with the steam. A portion of the combustion energy is used to generate superheated dry steam in a boiler type heat exchanger 5. The generated steam 9 is driving the SD-DCSG 10. The water for the non-direct boiler 5 is supplied from the commercially available water treatment plant in BLOCK 2. Low quality water from BLOCK 2 is fed directly into the SD-DCSG where it is converted into steam. In this scheme, the conversion is only partial as the discharge from 10 is in a liquid form 12. The liquid discharge 12 is directed to the combustion DCSG to generate an overall ZLD
(Zero Liquid Discharge) facility. The steam from the SD-DCSG 8 is injected into an underground formation through an injection well 16 for EOR.

[36] FIGURE 7 is a schematic view of an integrated facility of the present invention with a commercially available steam generation facility and FOR for heavy oil production. The steam for FOR is generated using a lime softener based water treatment plant and OTSG
steam generation facility. This type of configuration is most common in FOR facilities in Alberta. It recovers bitumen from deep oil sand formations using SAGD, CSS etc. Produced emulsion 3 from the production well 54, is separated inside the separator facility to bitumen 4 and water 5. There are many methods from separating the bitumen from the water. The most common one uses gravity.
Light hydrocarbons can be added to the product to improve the separation process.
The water, with some oil remnants, flows to a produced water de-oiling facility 6. In this facility, de-oiling polymers are added. Waste water, with oil and solids, is rejected from the de-oiling facility 6. In a traditional system, the waste water would be recycled or disposed of in deep injection wells. The de-oiled water 10 is injected into a warm or hot lime softener 12, where lime, magnesium oxide and other softening chemicals are added 8. The softener generates sludge 13.

[37] In a standard facility, the sludge is disposed of in a landfill. The sludge is semi-wet, and hard to stabilize. The softened water 14 flows to a filter 15 where filter waste is generated 16. The waste is sent to an ion-exchange package 19, where regeneration chemicals 18 are continually used and rejected with carry-on water as waste 20. In a standard system, the treated water 21 flows to an OTSG
where approximately 80% quality steam is generated 27. The OTSG typically uses natural gas 25 and air 26 to generate steam. The flue gas is released to the atmosphere through a stack 24. Its saturated steam pressure is around 100bar and the temperature is slightly greater than 300C.
In a standard SAGD system the steam is separated in a separator, to generate 100% steam 29 for FOR and blow-down water. The blow down water can be used as a heat source and also to generate low pressure steam. The steam, 29 is delivered to pads, where it is processed and injected into the ground through an injection well 53. In the current method, additional dry superheated steam flow is produced to drive the SD-DCSG in BLOCK
1 to generate additional injection steam from the waste water stream. The production well 54, located in the FOR field facilities BLOCK 4, produces an emulsion of water and bitumen 3. In some FOR facilities, injection and production occur in the same well, where the steam can be 80%
quality steam 27. The steam is then injected into the well with the water. This is typical of the CSS pads where wells 53 and 54 are basically the same well.

[38] The reject streams include the blow down water from OTSG 23, as well as the oily waste water, solids and polymer remnants from the produced water de-oiling unit.
This also includes sludge 13 from the lime softener, filtrate waste 16 from the filters and regeneration waste from the lon-Exchange system 20. The reject streams are collected 33 and injected directly 33A into Steam Drive Direct Contact Steam Generation 30 in BLOCK 1. The SD-DCSG can be vertical, stationary, horizontal or rotating. Dry solids 35 are discharged from the SD-DCSG, after most of the liquid water is converted to steam. The SD-DCSG generated steam 31 temperatures can vary between 120C and 300C. The pressure can vary between lbar and 50 bar. The produced steam 32 can be injected directly 45A into the injection well 53, possibly after additional solids and contamination removal in BLOCK 32. Another option is to wash the generated steam in wet scrubber 50 in BLOCK 2. BLOCK 2 is optional and can be bypassed by flows 33A and 45A. The produced steam from the SD-DCSG 31 is injected into a scrubber vessel 50 where the steam gas is washed with saturated water 48 that was condensed from the produced gas 31 or from additional liquid water supplied to the wet scrubber vessel 50 to remove the solid remnants and possibly chemical contaminates. Solid rich water 51 is continually removed from the bottom of vessel 50. It is recycled back to the SD-DCSG, where the solids are removed in dry or semi-dry form 35. The liquid water is converted back to steam 31. The saturated wash water in vessel 50 is generated by removing heat through non-direct heat exchange with the feed water 33. A portion of the steam condenses to generate washing liquid water at vessel 50. The liquid water continually recycled to enhance the washing and the wet scrubbing. The SD-DCSG is driven by superheated steam generated by the steam generator 23 or in a separate boiler or in a separate heat exchanger within the boiler (re-heater type heat is exchanged to heat steam to produce a superheated steam).
There are many varieties of commercially available options to generate the dry steam needed to drive the process in the SD-DCSG. The generated clean steam 45 is injected into an underground formation for EOR.

[39] FIGURE 8 is a schematic of the invention with an open mine oilsand extraction facility, where the hot process water for the ore preparation is generated from condensing the steam produced from the fine tailings using a SD-DCSG. A typical mine and extraction facility is briefly described in BLOCK 5. The tailing water 27 from the oilsand mine facility is disposed of in a tailing pond. The tailing ponds are built in such a way that the sand tailings are used to build the containment areas for the fine tailings. The tailing sources come from Extraction Process. They include the cyclone underflow tailings 13, mainly coarse tailings, and the fine tailings from the thickener 18, where flocculants are added to enhance the solid settling and recycling of warm water.
Another source of fine tailings is the Froth Treatment Tailings, where the tailings are discarded using the solvent recovery process- characterized by high fines content, relatively high asphaltene content, and residual solvent. (See "Past, Present and Future Tailings, Tailing Experience at Albian Sands Energy" a presentation by Jonathan Matthews from Shell Canada Energy on December 8, 2008 at the International Oil Sands Tailings Conference in Edmonton, Alberta).
A sand dyke 55 contains a tailing pond. The sand separates from the tailings and generates a sand beach 56. Fine tailings 57 are put above the sand beach at the middle-low section of the tailing pond. Some fine tailings are trapped in the sand beach 56. On top of the fine tailing is the recycled water layer 58.
The tailing concentration increases with depth. Close to the bottom of the tailing layer are the MFT
(Mature Fine Tailings). (See "The Chemistry of Oil Sands Tailings: Production to Treatment"
presentation by R.J. Mikula, V.A. Munoz, O.E. Omotoso, and K.L. Kasperski of CanmetENERGY, Devon, Alberta, Natural Resources Canada on December 8, 2008 at the International Oil Sands Tailings Conference in Edmonton, Alberta). The recycled water 41 is pumped from a location close to the surface of the tailing pond (typically from a floating barge). The fine tailings that are used for generating steam and solid waste in this invention are the MFT. They are pumped from the deep areas of the fine tailings 43. MFT 43 is pumped from the lower section of the tailing pond and is then directed to the SD-DCSG in BLOCK 1 and in BLOCK 3. The SD-DCSG that includes BLOCKS 1-4 is described in Figure 5B. However, any available SD-DCSG that can generate gas and solids from the MFT can be used as well. Due to the heat from the superheated steam and pressure inside the SD-DCSG, the MFT turns into gas and solids as the water is converted to steam.
The solids are recovered in a dry form or in a semi-dry, semi-solid slurry form. The semi-dry slurry form is stable enough to be sent back into the oilsand mine without the need for further drying to support traffic. The produced steam needed for extraction and froth treatment, is generated by a standard steam generation facility 61 used to generate the driving steam for the DCSG in BLOCK 1 or from the steam produced from the SD-DCSG 62. The generated saturated steam 47 is mixed with the process water 41 in mixing enclosure 45 to generate the hot water 52 used in the extraction process in BLOCK 5. By continually consuming the fine tailing water 43, the oil sand mine facility can use a much smaller tailing pond as a means of separating the recycled water from the fine tailings. This solution will allow for the creation of a sustainable, fully recyclable water solution for the open mine oilsand facilities.

[40] FIGURE 9 is a schematic view of the invention with an open mine oilsand extraction facility and a prior art commercially available pressurized fluid bed boiler that uses combustion coal for power supply. Examples of pressurized boilers are the Pressurized Internally Circulating Fluidized-bed Boiler (PICFB) developed and tested by Ebara, and the Pressurized-Fluid -Bed-Combustion-Boiler (PFBC) developed by Babcock-Hitachi. Any other pressurized combustion boiler that can combust petcoke or coal can be used as well. BLOCK 1 is a prior art Pressurized Boiler. Air 64 is compressed 57 and supplied to the bottom of the fluid bed combustor to support the combustion. Fuel 60, like petcoke, is crushed and grinded, possibly with lime stone 61 and water 62, to generate pumpable slurry 59. Water 62 is recycled water with high level of contaminates 38, as discharged from the SD-DCSG 28. Some portion or stream 38A can be injected above the combustion area to directly recover heat from the combustion gas to generate steam. The boiler includes an internal heat exchanger 63 to generate high pressure steam 51 to drive the SD-DCSG.
The steam 51 is generated from steam boiler drum 52 with boiler water circulation pump 58. The boiler heat exchanger 63 recovers energy from the combustion. BFW 37 is fed to the boiler to generate steam 51. The steam can be heated again in a boiler heat exchanger (not shown) to generate a superheated steam stream. The steam used to drive the SD-DCSG 28.
The boiler generates pressurized combustion gas and steam mixture 1 from the SD-DCSG
discharged water 24 at a pressure of 103kpa and up to 1.5Mpa and temperatures of 2000-9000. The discharge flow is treated in BLOCK 3 to generate a steam and combustion gas mixture for EOR. The mixture 8 is injected into an underground formation through an injection well 7. There is no need to remove solids from the combustion gas 1 because this gas is fed to the DCSG in Block 3 that works as a wet scrubber and remove solids and possibly contaminated gas like SOx and NOx while creating a steam and combustion gas mixture. Solids from the fluid bed of the PFBC 55 can be recovered to maintain the fluid bed solids level. (This is a common practice in FBC (Fluid Bed Combustion) and PFBC). The fluid bed solids can be mixed with the DCSG solids from BLOCK 3 (not shown).
The pressurized combustion gases leaving AREA#1 are mixed with the concentrate effluent from SD-DCSG 28 and possibly with other low quality waste water and slurry sources, like HLS/WLS
sludge produced by SAGD/CSS water treatment plant (not shown). Block 2 includes a commercially available FOR facility, like SAGD, where the water and bitumen emulsion is treated to generate BFW
water quality and low quality water that is fed into the SD-DCSG. There will be two types of injection wells - for the injection of pure steam from the SD-DCSG 6 and for the injection of a mixture of steam and combustion gases, mainly CO2 7. It is possible to combine the two types of FOR
fluids in one production facility where the aging injection wells will be converted from pure steam to a steam and combustion gas mixture to pressurize the underground formation and increase the bitumen recovery due to the CO2 dissolved that increases the bitumen fluidity.

[41] FIGURE 10 is a schematic diagram of DCSG pressurized boiler and SD-DCSG.
Fuel 2 is mixed with air 55 and injected into a Pressurized Fluidized-Bed Boiler 51. The fuel 2 can be generated from the water-bitumen separation process and includes reject bitumen slurry, possibly with chemicals that were used during the separation process and sand and clay remains. Additional low quality carbon fuel can be added to the slurry. This carbon or hydrocarbon fuel can include coal, petcoke, asphaltin or any other available fuel. Lime stone can be added to the fuel 2 or to the water 52 to remove acid gases like SOx. The Fluidized-Bed boiler is modified with water injection 52 to convert it to a DCSG. It includes reduced capacity internal heat exchangers to recover less combustion heat. The reduction in the heat exchanger required capacity is because more combustion energy will be consumed due to the direct heat exchange with the water within the fuel slurry 2 and the additional injected solid rich water 52 leaving less available heat to generate high pressure steam through the boiler heat exchangers 56. The boiler produces high-pressure steam 59 from distilled, de-mineralized feed water 37. The produced steam 59, or part of it 31, can be re-heated in re-heater 56 to generate super heated seam 32 to operate the SD-DCSG
in BLOCK 3. There are several pressurized boiler designs for BLOCK 1 that can be modified with direct water injections.
One example of such a design is the EBARA Corp. PICFB (see paper No. FBC99-0031 Status of Pressurized Internally Circulating Fluidized-Bed Gasifier (PICFG) development Project dated May-16-19, 1999 and US RE37,300 E issued to Nagato et al on July 31, 2001). Any other commercially available Pressurized Fluidized Bed Combustion (PFBC) can be used as well.
Another modification to the fluid bed boiler can be reducing the boiler combustion pressure down to 102kpa. This will reduce the plant TIC (Total Installed Cost) and the pumps and compressors' energy consumption.
The superheated steam 32 is supplied to BLOCK 3 where it is used by the SD-DCSG 28 for generating additional steam from low quality water. BLOCK 2 includes a water treatment facility as previously described. The steam and combustion gas mixture stream 1 is supplied to BLOCK
2 where the water and heat can be used for generating clean BFW by evaporation / distillation facility. The pressure energy in flow 1 can be used to separate CO2 from the NCG using commercially available membrane technologies. The combustion oxidizer, like air, 55 is injected at the bottom of the boiler to maintain the fluidized bed. High pressure 100% quality steam 59 is generated from distilled water 37 through heat exchange inside the boiler 51. The generated steam 59 can be further heated in heat exchanger 56 to generate super-heated steam 32 that is used in BLOCK 3 as the driving steam for the SD-DCSG
28. The steam generated in BLOCK 3 is injected, through an injection well 16, into an underground formation for EOR. Hydrocarbons and water 13 are produced from the production well 15. The mixture is separated in a commercially available separation facility in BLOCK
2.

[42] FIGURE 11 is a schematic diagram of the present invention which includes a steam generation facility, SD-DCSG, a fired DCSG and MED water treatment plant.
BLOCK 1 is a standard, commercially available steam generation facility that includes an atmospheric steam boiler or OTSG 7.
Fuel 1 and air 2 are combusted under atmospheric pressure conditions. The discharged heat is used to generate steam 5 from de-mineralized distilled water 29. The combustion gas is discharged through stack 3. The generated steam is supplied to SD-DCSG 11 in BLOCK 4 that generates additional steam from the concentrated brine 38 discharged from the MED in BLOCK 2. The generated steam 8 is injected into an underground formation 6. The liquid discharge 14 from SD-DCSG 11 is injected into an internally fired DCSG 15 in BLOCK 3. Carbon fuel 41, like petcoke or coal slurry, is mixed with oxygen-rich gas 42 and combusted in a DCSG 15. Discharged liquids from the SD-DCSG 11 are mixed with the pressurized combustion gas to generate a stream of steam-rich gas and solids 13. To reduce the amount of SO2, limestone can be added to the brine water 14 or to the fuel 41 injected into the DCSG, to react with the SO2. The solids are separated in separator 16. The separated solids 17 are discharged in a dry form from the solids separator 16 for disposal. The steam and combustion gas 12 flows to heat exchanger 25 and condenser 28. The steam in gas flow 12 is condensed to generate condensate 24.
The condensate is treated (not shown) to remove contaminants and generate BFW that is added to the distillate BFW 29 then supplied to the steam generation facility. The NCG (Non-Condensation Gas) 40 is released to the atmosphere or used for further recovery, like CO2 extraction. The heat recovered in heat exchanger 28 is used to generate steam to operate the MED 30 (a commercially available package). The water 1 fed to the MED is de-oiled produced water, possibly with make-up underground brackish water. The Multi Effect Distillation takes place in a series of vessels (effects) 31 and uses the principles of condensation and evaporation at a reduced pressure. The heat is supplied to the first effect 31 in the form of steam 26. The steam 26 is injected into the first effect 31 at a pressure of 0.2bar to 12 bar. The steam condenses while feed water 32 is heated. The condensation 34 is collected and used for boiler feed water 37. Each effect consists of a vessel 31, a heat exchanger, and flow connections, 35. There are several commercial designs available for the heat exchanger area: horizontal tubes with a falling brine film, vertical tubes with a rising liquid, a falling film, or plates with a falling film. The feed water 32 is distributed on the surfaces of the heat exchanger and the evaporator. The steam produced in each effect condenses on the colder heat transfer surface of the next effect. The last effect 39 consists of the final condenser, which is continually cooled by the feed water, thus preheating the feed water 1. To improve the condensing recovery, the feed water can be cooled by air coolers before being introduced into the MED (not shown). The feed water may come from de-oiled produced water, brackish water, water wells or from any other locally available water source. The brine concentrate 2 is recycled back, to the SD-DCSG in BLOCK 4.

[43] FIGURE 11A is a view of the present invention that includes a steam generation facility, SD-DCSG and MED water treatment plant. BLOCK 1 is a standard, commercially available steam generation facility for generating super heated driving steam 5. The driving steam 5 is fed to SD-DCSG in BLOCK 3. Discharged brine from the commercial MED facility in BLOCK 2 is also injected to the SD-DCSG
15 and converted to steam and solid particles 13. The solids 17 are removed for disposal. A portion of the generated steam 12 is used to operate the MED through heat exchanger /
condenser 28. The condensate 24, after further treatment (not shown), is used as BFW. The MED
produces distilled BFW 29 that is used to produce the driving steam at the boiler 7. The steam 8 is injected through injection well 6 for EOR.

[44] FIGURE 12 is an illustration of the use of a partial combustion gasifier with the present invention for the production of syngas for use in steam generation, a SD-DCSG
and a DCSG combined with a water distillation facility for ZLD. The system contains few a commercially available blocks, each of which includes a commercially available facility:

BLOCK 1 includes the gasifier that produces syngas.

BLOCK 2 includes a commercially available steam generation boiler that is capable of combusting syngas.

BLOCK 3 includes a commercially available thermal water distillation plant.

BLOCK 7 includes syngas treatment plant where part of the syngas can be used for hydrogen production etc.

BLOCK 5 includes a water-oil separation facility with the option of oily water discharge for recycling into the SD-DCSG.

BLOCK 4 includes SD-DCSG which generates the injection steam.
BLOCK 6 includes DCSG.

Carbon fuel 5 is injected with oxygen rich 6 gas to a pressurized gasifier 7.
The gasifier shown is a typical Texaco (GE) design that includes a quenching water bath at the bottom. Any other pressurized partial combustion gasifier design can also be used. The gasifier can include a heat exchanger, located at the top of the gasifier (near the combustion section), to recover part of the partial combustion energy to generate high pressure steam. At the bottom of the gasifier, there is a quenching bath with liquid water to collect solids. Make-up water 13 is then injected to maintain the liquid bath water level. The quenching water 15, which includes the solids generated by the gasifier, is injected into a DCSG 15 where it is mixed with the produced hot syngas discharged from the gasifier 12. The DCSG also consumes the liquid water discharge 52 from the SD-DCSG 50. In the DCSG, the water is evaporated into pressurized steam and solids (which were carried with the water and the syngas into the DCSG). The DCSG generates a stream of gas and solids 16. The solids 19 are removed from the gas flow by a separator 17 for disposal. The solids lean gas flow 18 (after most of the solids have been removed from the gas) is injected into a pressurized wet scrubber 20 that removes the solid remains and can generate saturated steam from the heat in gas flow 18 as well. Solids rich water 25 is continually rejected from the bottom of the scrubber and recycled back to the DCSG 15. Heat 27 is recovered from the saturated water and syngas mixture 21 while condensing steam 21 to liquid water 35 and water lean syngas 36.
The condensed water 35 can be used as BFW after further treatment to remove contaminations (not shown). The heat 27 is used to operate a thermal distillation facility in BLOCK 3. There are several commercially available facilities for this, like MSF (Multi Stage Flashing) or MED (Multi Effect Distillation). The distillation facility uses de-oiled produced water 30, possibly with make-up brackish water 31 and heat 27, to generate a stream of de-mineralized BFW 29 for steam generation and a stream of brine water 28, with a high concentration of minerals. The generated brine 28 is recycled back to the SD-DCSG 50 in BLOCK 4. The syngas can be treated in commercially available facilities BLOCK 7 to remove H2S using amine or to recover hydrogen. The treated syngas 37, together with oxidizer 38, is used as a fuel source in the commercially available steam generation facility BLOCK 2. The super heated steam 40 is generated in steam boiler 39 from the BFW 29. The steam from the boiler 40, possibly together with the steam generated by the gasifier 10, is injected into the SD-DCSG 50 in BLOCK 4 where additional steam is generated from low quality water 53. The generated steam 51 is injected into an underground formation for EOR. The produced bitumen and water recovered from production well 44 are separated in the water-oil separation facility BLOCK 5 to produce bitumen 33 and de-oiled water 30.
Oily water 34 can be rejected and consumed in the SD-DCSG 50. By allowing continuous rejection of oily water, the chemical consumption can be reduced and the efficiency of the oil separation unit can be improved.

Claims

1. A method for steam production for extraction of heavy bitumen, said method comprising the steps of:

(a) generating or heating steam through indirect heat exchange;

(b) mixing said steam gas with liquid water having solids and organics so as to transfer said liquid water from a liquid phase to a gas phase;

(d) removing solids to produce solids free gas phase steam;
(h) using produced gas phase steam to recover oil.

2. A system for producing steam for extract heavy bitumen, the system comprising:

a combustion heater, mixing fuel with oxidation gases therein, forming a mixture, combusting the mixture, recovering combustion heat to generate or heat steam;

a steam drive direct contact steam generator, mixing steam generated by said heater with water containing levels of solids therein to form a steam stream and solids discharged streams, wherein said steam drive direct contact steam generator is in fluid connection to said heater; and an enhanced oil recovery facility in fluid connection to said steam drive direct contact steam generator.