CA2642295A1 - Upgrading of bitumen using supercritical wet oxidation - Google Patents

Description

Title: Upgrading of bitumen using SuperCritical Wet Oxidation The present relates to the use of "supercritical water oxidation" to burn a portion of bitumen, heavy oil or the like (i.e. any hydrocarbon type material having a low API e.g.
an API of 16 or less) in order to provide heat to the remaining bitumen, heavy oil or the like so as to raise the temperature thereof to a cracking temperature for upgrading the bitumen, heavy oil or the like to a (more) pumpable product for transfer to a downstream refinery. The upgrading involves subjecting the remaining bitumen, heavy oil or the like to cracking conditions to produce (in situ) material(s) of smaller molecular weight which may act as diluent type material(s) so as to obtain a cracked product (e.g.
API 20 -30) which is not only relatively better suited for being pumped than the starting bitumen, heavy oil or the like but which as desired or necessary may have a reduced mineral content.

The American Petroleum Institute gravity, or API gravity (herein sometimes referred to simply as API), is a measure of how heavy or light a petroleum liquid is compared to water. If its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks. API gravity is thus a measure of the relative density of a petroleum liquid and the density of water, but it is used to compare the relative densities of petroleum liquids. For example, if one petroleum liquid floats on another and is therefore less dense, it has a greater API gravity. Although mathematically API gravity has no units, it is nevertheless referred to as being in "degrees". API gravity is graduated in degrees on a hydrometer instrument and was designed so that most values would fall between 10 and 70 API gravity degrees.

Generally speaking 40 to 45 API gravity degree oils have a greatest commercial price and values outside this range have lower commercial price. Above 45 degrees API
gravity the molecular chains become shorter and less valuable to a refinery.

Crude oil is classified as light, medium or heavy, according to its measured API gravity.

Light crude oil is defined as having an API gravity higher than 31.1 API
Medium oil is defined as having an API gravity between 22.3 API and 31.1 API
Heavy oil is defined as having an API gravity below 22.3 API.

Simply put, bitumen sinks in fresh water, while oil floats.

Crude oil with API gravity less than 10 API is referred to as extra heavy oil or bitumen.
Bitumen derived from the oil sands deposits in the Alberta, Canada area has an API
gravity of around 8 API. It is 'upgraded' to an API gravity of 31 API to 33 API and the upgraded oil is known as synthetic crude.

The following, by way of example only will in particular relate to bitumen upgrading which may for example be carried out on site at a bitumen field wherein the bitumen is extracted by steam assisted gravity techniques. However it is to be understood herein, that the invention is applicable to the upgrading (i.e. the rendering better or more easily pumpable) of other similar or analogous types of hydrocarbon materials (e.g.
any hydrocarbon material having an undesirable API from the stand point of pumping such as, for example, an API of 16 or less (e.g. an API of less than 12 e.g. of 8 to 12), e.g.
heavy oil).

Background Supercritical water exists at temperatures and pressures above the critical point of water (of 221 bar and 374 C). The physical chemical properties of supercritical water is extensively described in Appendix 1 hereinafter (Supercritical Water oxidation Technology, Tester et ao, Relevant properties of supercritical water may be summarised as follows.

2 = Supercritical water has unique solvent properties in that hydrocarbons and gasses are 100% solvable and inorganic (salts) are insoluble and will precipitate out.

= When oxygen is dissolved in supercritical water and comes in contact with organic material (i.e. hydrocarbon) it results in a spontaneous combustion.
This combustion is often termed SuperCritical Wet Oxidation (SCWO) = Supercritical water has unique chemical properties in that it possesses a certain reforming activity it can hydrolyse cellulose, it can act as a reducing agent (hydrogen donor) in hydrocarbon cracking and reforming.

There exists numerous references to processes for cracking, desulfurizing, denitrifying, demetalating, and generally upgrading hydrocarbon or coal fractions by processes involving supercritical water. As early as 1976 McCollum et al.(US-Patent

3,983,027) described a supercritical water process for upgrading coal in absence of hydrogen, carbon monoxide or catalysts. Process patents have been filed covering various aspects of coal and bitumen recovery and upgrading by application of supercritical water.
The specific application of supercritical water for upgrading bitumen is extensively described by Kamimura et al (Fuels for the Year 2000 and Beyond, Am. Chem. Soc Division of Fuel Chemistry, Boston, 1998) and by Berkowitz et al, (USPTO 20070056881).
Kamimura et al. has also filed a patent (CA 2,220,800) which specifically addresses the application of supercritical water to the SAGD-process.

The SuperCritical Wet Oxidation (SCWO) component of the present invention exploits (e.g. in a reactor) combustion of a portion of hydrocarbon (e.g. petroleum) type material to provide the energy needed for the upgrading, etc. thereof; i.e.
exploitation of the supercritical conditions for a mixture of hydrocarbon material and water. It is to be understood herein that reference to" supercritical water oxidation component"
is a reference to a component wherein the supercritical conditions are in relation to a mixture of hydrocarbon material and water.

The present invention is in particular distinct from the respective Kammimura, Berkowitz and any other related processes in that energy recovery (and optionally carbon capture) may if desired or necessary comprise part of the bitumen recovery process of the present invention.

The invention may, for example, be directed to an upgrade method and/or system which may be used to upgrade the hydrocarbon content or moiety of a material such as a hydrocarbon source component comprising a mixture of hydrocarbon material (e.g. bitumen or any hydrocarbon material having an API of 16 or less e.g. heavy oil) and water; the mixture may for example be at a pressure P2 of less than or equal to10 bar and a temperature of TZ of less than 180 C;
the mixture may for example comprise a water to oil mass ratio of 3:1 but such ratio may for example be in the range of from 3:1 to (where possible) 1:1.

An upgrade method and/or system of the present invention may comprise a) a pressurizing component (e.g. pump element) for subjecting a mixture of hydrocarbon material (e.g. bitumen, heavy-oil, etc.) and water to a predetermined pressure (e.g. P3) suitable for supercritical type water oxidation (e.g. a pressure of 221 bar or higher; the temperature T3 of the pressurised water and oil combination may for example be less than about 180 C;
b) a supercritical water oxidation (e.g. reactor) component to which is fed the obtained pressurised mixture of hydrocarbon material (e.g.
bitumen, heavy-oil, etc.) and water as well as an oxidising agent (e.g.
pure 02, hydrogen peroxide, air, etc. but pure 02 has the advantage over air in that undesirable nitrogen by products may be avoided ) for inducing combustion of a predetermined amount of bitumen (or heavy-oil) material in order to raise the temperature of the hydrocarbon material (e.g. bitumen, etc.)-water mixture to cracking temperature

4 level (e.g. a temperature of from 372 C to 700 C or higher where applicable), the conditions of pressure and temperature of the hydrocarbon material (e.g. bitumen, etc.)-water feed being suitable for supercritical water oxidation; e.g. the amount, pressure and temperature of injected 02 may be controlled with a view to obtaining the desired temperature conditions for cracking purposes due to such in situ combustion (e.g. the oxygen feed pressure may be just sufficient to be able to be injected into the bitumen-water mixture but may as desired or necessary be higher); and c) a cracking(/mineral separation) component configured to hold the heated hydrocarbon material (e.g. bitumen)-water mixture (e.g. as a function of temperature and pressure, if present also type of catalyst, so as to provide a residence time which may vary from minutes to seconds e.g. a residence time of fifteen minutes or less) for facilitating the desired upgrading (i.e. upgrading meaning cracking to obtain a cracked product having the desired pumpability characteristics e.g. an API of 20 to 30) and, if desired, for example, mineral separation as described herein.

In accordance with the present invention the pressurizing component, supercritical water oxidation component and the cracking (/mineral separation) component may be individual components or may be combined with one or both of the other components.
The invention may, for example, be directed to an upgrade method and/or system which may comprise a plurality of components. A system in accordance with the present invention may for example in particular comprise;

- a hydrocarbon source component comprising a mixture of hydrocarbon material (e.g.
bitumen or any hydrocarbon material having an API of 16 or less e.g. heavy oil) and water; (e.g. at a pressure P2 of less than or equal to10 bar and a temperature of T2 of less than 180 C; e.g. at a water to oil mass ratio of 3:1 but such ratio may for example be in the range of from 3:1 to (where possible) 1:1;

5 - a pressurizing component (e.g. pump element) for subjecting the hydrocarbon material (e.g. bitumen, heavy-oil, etc.) and water to a predetermined pressure (e.g.
P3) suitable for supercritical type water oxidation (e.g. a pressure of 221 bar or higher;
the temperature T3 of the pressurised water and oil combination may for example be about the same as T2 (see above);

- a supercritical water oxidation (e.g. reactor) component to which is fed the obtained pressurised mixture of hydrocarbon material (e.g. bitumen, heavy-oil, etc.) and water as well as an oxidising agent (e.g. pure 02, air, etc.) for inducing combustion of a predetermined amount of hydrocarbon material (e.g. bitumen, heavy-oil or the like) in order to raise the temperature of the bitumen-water mixture to cracking temperature level, the conditions of pressure and temperature of the bitumen-water feed being suitable for supercritical water oxidation; e.g. the amount, pressure and temperature of injected 02 may be controlled with a view to obtaining the desired temperature conditions for cracking purposes due to such in situ combustion;

- a cracking(/mineral separation) component configured to hold the heated mixture of hydrocarbon material (e.g. bitumen, etc.) as a function of temperature and pressure, if present also type of catalyst, so as to provide a residence time which may vary from minutes to seconds e.g. a residence time of fifteen minutes or less) -water mixture for facilitating the desired upgrading (i.e. upgrading meaning cracking to obtain a cracked product having the desired pumpability characteristics e.g. an API of 20 to 30) and, for example, mineral separation as described herein;

- a temperature reduction component for reducing the temperature of the cracked product for separation of the cracked product into a water phase and an organic phase;
e.g. reduce to a temperature, for example, less than 372 C (e.g. from 300 to 372 C);

- a phase separation component for splitting the temperature reduced output from the cracking(/separation) component into water phase stream and an organic phase stream comprising a COZ part and an oil part; the water phase stream may fior example being directed to the pressurizing) component to pass there through so as to reduce its pressure

6 for subsequent injection back into the in-ground reservoir component while inducing pressurisation of the extracted bitumen (or heavy-oil) and water as mentioned above;

- an organic phase splitter component for splitting the organic phase into an oil stream (e.g. of API 20 to 30) and a CO2 stream; and - an optional CO2 capture component - or optionally the CO2 could be released into the atmosphere if traded for carbon credit.

The invention may in particular be exploited in conjunction with a steam assisted gravity drainage (SAGD), namely steam assisted gravity drainage (SAGD) component comprising a steam injection element for injecting steam at predetermined pressure and temperature (e.g. a pressure P1 of less than 35 bar (e.g. up to 10 bar) and a temperature T1 of less than 250 C (e.g. from 120 to 250 C; e.g. from 120 to 180 C) into the in-ground bitumen (or heavy oil) reservoir and a fluid extraction element for the extraction of bitumen (or heavy-oil) and water out of the reservoir (e.g. at a water to oil mass ratio of 3:1 but such ratio may for example be in the range of from 3:1 to (where possible) 1:1; at a temperature T2 < Tl (e.g. 100 to 200 ); at a pressure P2 < PI( e.g. a pressure of 15 bar or less)); the injection and/or extraction may be assisted by pump elements but if desired the pressure of the steam injection may be arranged such the input steam pressure is not only sufficient to inject steam into the reservoir but also to force the water/oil mixture out of the reservoir Thus the invention may, for example, be directed to an upgrade method and/or system for upgrading bitumen (etc.) from an in ground reservoir which may comprise a plurality of additional components. A system in accordance with the present invention may thus for example comprise:

la) a hydrocarbon in-ground reservoir component comprising bitumen or heavy oil (e.g. any hydrocarbon material having an API of 16 or less);

2a) a steam assisted gravity drainage (SAGD) component comprising a steam injection element for injecting steam at predetermined pressure and temperature (e.g. a pressure P1 of less than 35 bar (e.g. up to 10 bar) and a

7 temperature Tl of less than 250 C (e.g. from 100 to 180 C) into the in-ground bitumen (or heavy oil) reservoir and a fluid extraction element for the extraction of bitumen (or heavy-oil) and water out of the reservoir (e.g. at a water to oil mass ratio of 3:1 but such ratio may for example be in the range of from 3:1 to (where possible) 1:1; at a temperature T2 < T1 and a pressure P2 <
P1); the injection and/or extraction may be assisted by pump elements but if desired the pressure of the steam injection may be arranged such the input steam pressure is not only sufficient to inject steam into the reservoir but also to force the water/oil mixture out of the reservoir;

3a) a pressurizing component (e.g. pump element) for subjecting the extracted bitumen (or heavy-oil) and water to a predetermined pressure (e.g.
P3) suitable for supercritical water oxidation (e.g. a pressure of 221 bar or higher; the temperature T3 of the pressurised water and oil combination may for example be about the same as T2 (see above);

4a) a supercritical water oxidation (e.g. reactor) component to which is fed the obtained pressurised bitumen (or heavy-oil) and water as well as an oxidising agent (e.g. pure 02, air, etc.) for inducing combustion of a predetermined amount of bitumen (or heavy-oil) material in order to raise the temperature of the bitumen-water mixture to cracking temperature level, the conditions of pressure and temperature of the bitumen-water feed being suitable for supercritical water oxidation; e.g. the amount, pressure and temperature of injected 02 may be controlled with a view to obtaining the desired temperature conditions for cracking purposes due to such in situ combustion;

5a) a cracking(/mineral separation) component configured to hold (e.g.
provide a residence time of fifteen minutes) for facilitating the desired upgrading (i.e. upgrading meaning cracking to obtain a cracked product having the desired pumpability characteristics e.g. an API of 20 to 30) and, for example, mineral separation as described herein;

8 6a) a temperature reduction component for reducing the temperature of the cracked product for separation of the cracked product into a water phase and an organic phase; e.g. reduce to a temperature, for example, less than 372 C (e.g. from 300 to 372 C);

7a) a phase separation component for splitting the temperature reduced output from the cracking(/separation) component into water phase stream and an organic phase stream comprising a COz part and an oil part; the water phase stream may for example being directed to the pressurizing) component to pass there through so as to reduce its pressure for subsequent injection back into the in-ground reservoir component while inducing pressurisation of the extracted bitumen (or heavy-oil) and water as mentioned above;

8a) an organic phase splitter component for splitting the organic phase into an oil stream (e.g. of API 20 to 30) and a COZ stream;

9a) an optional CO2 capture component - or optionally the CO2 could be released into the atmosphere if traded for carbon credit.

If desired the pressurizing component and the supercritical water oxidation component may be combined into a more or less single component.

The invention is directed to a method and/or system which may be run continuously; run by batch; or run semi batch wise. The method and\or system may, for example, be run as a closed or open loop for the extraction of bitumen from a bitumen reservoir.

The system can be run in batch or in continuous operation:
= Batch:
o The system may be fed at the proper pressure (i.e. more than 221 bar or) in the range of necessary pressure to eventually reach the vapour-liquid region indicative of conditions under which water has the properties of supercritical water until the reactor is full. Then the 02 is injected to increases the temperature needed to get the

9 supercritical water properties required for cracking. The fluids stay in the reactor until the cracking of heavy oil/bitumen is cracked to an API of 20 to 30 under the specific condition of the super critical water properties and until the precipitation of the minerals settling down to the bottom of the vessel is completed. Then the vessel is emptied into an oil and water separator to create a stream of Water and a stream of oil and dissolved C02.
= Continuous o The same process is applied at the exemption that the reactor is design to have a constant and uniform flow that produce a sufficient residence time to properly achieved the cracking of the heavy oil/bitumen as well as the separation of the precipitate mineral to the bottom of the reactor.

In any event residence time for cracking is that needed to obtain the desired upgraded API number (e.g. 20 to 30) As may be appreciated the present invention may exploit or incorporate aspects of the following:
1. Super-Critical-Water-Oxidation (SCWO) process (see Appendix 1) 2. SAGD (Steam Assisted Gravity Drainage) process for bitumen recovery (see Appendix 2: Study on New Upgrading Process of Heavy Oils Combined with SAGD by means of Hydrothermal Treatment, Kishita et al) 3. Super-Critical-Water (SCW)-reforming and upgrading (see Appendix 2) 4. Supercritical steam turbines for power generation (available from Siemens or GE) The SCWO based process (i.e. method - system) of the present invention may for example comprises a closed loop, as illustrated in Fig. 1 a(just below), where live steam is injected into the bituminous formation (1) to facilitate mobilisation of the bitumen by gravity drainage and recovering at the surface as a hot bitumen-water (2) emulsion (SAGD). Said emulsion is pressurized to minimum 221 bar (3), fed into a Super-Critical-Wet-Oxidation (SCWO) reactor (4), and heated to minimum 374 C by direct injection of oxygen (5) which facilitates spontaneous stoiciometric combustion of a representative fraction of the bitumen in place. The reaction product comprises now three components, water, bitumen and C02, which exists in one homogeneous phase. The product is held at a specified pressure and temperature (exceeding the critical point of the hydrocarbon/water mixture) in a vessel (6) for the required time to facilitate the required upgrading (i.e. cracking) and demineralization (7) of the bitumen. Cold makeup water is added (10) The product is then further cooled (8) and/or depressurised (9) to below the critical point of the hydrocarbon/water mixture to facilitate a phase separation of water from the contentious oil/COZ-phase (11). Energy is recovered as the water phase is expanded over a steam turbine (12) down to the required pressure and temperature for live steam inj ection (1) into the bituminous formation. The homogeneous Oil/CO2 is cooled and depressurised (14) to below the critical point of CO2 (72 bar 31 C) to separate COZ from oil. CO2 is captured for deposit in the ground and oil goes to export.

; Ja On Site Bitumen Recovery, Upgrading, Carbon Capture & Storage St age Water makeup 10 6 T>372 C
T<3,C
P<71~ 3 Separator ~ SCwo o~ s OI~ prod'cuCOe & s p-r<s7z c 11 4 a&,~r_ grad-' water iflg minerals P>221ber - - - . - . _ . - . - . - . - . - . - . - . - . - . 3 T=235 C 1 T2F=8 T=180C bar Advantages of the present invention as compared to the standard SAGD process.
1. No independent diluents needed; make pumpable hydrocarbon fluid without the specific addition of a diluent(s);

2. On Site Upgrading (i.e. cracking);
3. No boiler or Steam generator may be needed; may use heated water from cracking to produce steam for injection into a hydrocarbon reservoir;
4. No water treatment may be needed; i.e. water from cracking may go directly to injection;
5. Oil Product may be demineralised (Sulphur and heavy metals removed by precipitation) 6. C02 may be captured & deposited and/or can be traded for carbon credits.

Stated otherwise the present invention provides a Method for on site bitumen recovering, upgrading and if desired carbon-capture by = Pressurise the bitumen/water emulsion from the SAGD process to a pressure above 221 bar.

= Heat said emulsion to a specific temperature e.g. above 377 C by injection of adequate amount of oxygen into a scwo reactor such that a single "liquid"
phase is formed. i.e. what structural (mechanical parts, etc.) as well as operational details = Hold the "liquid" for a certain time to allow for completion of the reforming/upgrading process (i.e. cracking) and to allow for the precipitation/settling of inorganic components = Remove the precipitates = Bring the said "liquid" into sub-critical-state by dropping pressure and or temperature to below the critical point such that a two-phase region is formed, comprising an lower aqueous phase and an upper hydrocarbon-CO2 phase.

= Recover energy by expanding the lower aqueous phase over a steam turbine down to the required pressure and temperature for steam injection in the SAGD
process.
= Cool and/or depressurise the upper phase to below its critical point to facilitate flashing of CO2.

= Optionally Recover C02 for under ground storage/deposit .

Stated otherwise the present invention also provides a system for on site bitumen recovery, and upgrading (and if desired or necessary carbon-capture) comprising:
= Pressurise the bitumen/water emulsion from the SAGD process to a pressure above 221 bar.

= Heat said emulsion to a specific temperature above 377 C by injection of adequate amount of oxygen into a swoc reactor such that a single "liquid"
phase is formed.

= Hold the "liquid" for a certain time to allow for completion of the reforming/upgrading process and to allow for the precipitation/settling of inorganic components.

= Remove the precipitates = Bring the said "liquid" into sub-critical-state by dropping pressure and or temperature to below the critical point such that a two-phase region is formed, comprising an lower aqueous phase and an upper hydrocarbon-CO2 phase.

= Recover energy by expanding the lower aqueous phase over a steam turbine down to the required pressure and temperature for steam injection in the SAGD
process.
= Cool and/or depressurise the upper phase to below its critical point to facilitate flashing of CO2.

= Optionally if desired or necessary Recover CO2 for under ground storage/deposit = If desired or necessary, a cracking aid material such KOH, NaOH, CO, H2 and/or cracking catalyst(s) may be exploited in the cracking step - if a cracking catalyst is exploited cracking may be accomplished after precipitate separation (e.g.
to avoid catalyst poisoning).

In accordance with a further example aspect of the present invention there is provided a recovery technology which may comprise a closed loop, as illustrated in Fig.2a, where live steam is injected into the bituminous formation (IA) to facilitate mobilisation of the bitumen by gravity drainage and recovering at the surface as a hot bitumen-water (2A) emulsion (SAGD). Said emulsion is pressurized to minimum 221 bar (3A), heated in a heat exchanger (4A) and fed into a vessel (6A) and further heated to the required temperature by being mixed with a hot stream exiting from a Super-Critical-Wet-Oxidation (SCWO) reactor (8A). The energy output from a SCWO-reactor is dictated by the hydrocarbon injection rate (13A) and the temperature is controlled by the water rate (12A + 15A). A spontaneous combustion of the hydrocarbons results when a stoiciometric excess, for example, of from 1 to 10% oxygen is injected (14a) into the SCWO-reactor. When excess oxygen is injected, the combustion is normally complete, yielding only C02 and water.

The reaction product comprises now three components, water, bitumen and C02, which exists in one homogeneous phase. The product is held at a specified pressure and temperature (exceeding the critical point of water) in the vessel (6A) for the required time to facilitate the required upgrading and demineralization of the bitumen.
The higher the temperature and pressure the lower the time required for upgrading. To achive less than one minute holding time for completion, high temperature and pressure is desired, but this is normally compromised by limitations in material properties of the vessels and piping. Minerals will precipitate and are removed by filter (7A). The product is then cooled by the feed stream in the heat exchanger (4A ) to below the critical point of water to facilitate a phase separation of water from the contentious oil/COZ-phase (9A).
Energy is recovered as the water phase is expanded over a Steam-or Pelton-turbine (IOA) down to the required pressure and temperature for live steam injection (IA) into the bituminous formation. The homogeneous Oil/CO2 is cooled (15A) and depressurised (16A) to below its critical point to separate C02 from oil. COZ is de-oiled in a scrubber (17A) and captured for deposit in the ground and oil goes to export (18A) .

Alterative features with respect to oxygen insertion to increase temperature:

o A) Using a reactor were the fluid is fed and uniformly mixed with the proper ratio of oxygen to increase the temperature to the super critical envelop. The residence time and the flow of Oxygen are variable that control the final temperature. (see figure 3a) o Using a pipe were the fluid is fed and uniformly mixed with the proper ratio of oxygen to increase the temperature to the super critical envelop. The residence time and the flow of Oxygen are variable that control the final temperature. (see figure 4a) o Using a stream flow were the fluid is fed and uniformly mixed with the proper ratio of oxygen to increase the temperature to a higher then desired final temperature. The residence time and the flow of Oxygen are variable that control the final temperature the stream flow is then blend back with the main stream to obtain the final temperature witch is in the supercritical envelop. (see figure 5a);
and o Using the pump as a mixing chamber to inject the 02 and the pipe or a reactor to generate the proper residence time for the reaction.
(see figure 6a);.

Cracking of heavy hydrocarbon materials is known. Upgrading or cracking as referred to herein is to be understood as relating to a process whereby process conditions such as pressure, temperature etc. are set so as to allow for the production of smaller molecular weight materials from materials of higher molecular weight rendering the final product mixture relatively more easily pumped than the initial starting material., i.e. the cracking may result in the production of materials which may in effect function as diluents for the remaining bitumen material - in any event no matter what the mechanism which raises the API number the purpose of the cracking is to achieve a product that is relatively pumpable.

Mineral separation may also be achieved during the supercritical condition, i.e. when the pressure and temperature are kept in the supercritical water envelop, the Water and the hydrocarbon become one phase and the mineral are precipitating and separated by gravity. It is then possible to collect at the bottom of the vessel Salt, Coke, Vanadium, heavy metal, sulphur etc..

For phase separation the temperature and pressure are decreased just under the Supercritical water envelop to initiate the phase separation between the Water and the organic phase including the CO2. Under the supercritical point water and organic phase become again two distinct phase. Because the density between the Water and the oil is substantial the separation is easier than the traditional water bitumen separation.

^ The temperature is less than 372 C
^ The pressure is less than 221 bar Carbon dioxide storage may be achieved by any known storage technique for this purpose - e.g. geological storage by be used whereby the carbon dioxide may be shipped by pipeline to a suitable geological storage site and injected into a suitable geological formation underground in any (known ) manner.

In the Annex A below (pages 38 to 43) a further example embodiment of the invention is shown - this further embodiment having a focus relating to energy & water recovery.

x f ~ ;,~~~;, ~' l~ = .
Chapter 3 Supercritical Water Oxidation Technology ~,.
Process Development and Fundamental Research Jefferson W. Testert, H. Richard Holgate', Fred J. Armellini', Paul A. Webley', William R. Kiliileaz, Glenn T. Hong2, and Herbert E. Barner3 1Chemical Engineering Department and Energy Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room F40-455, Cambridge, MA 02139 ~ 2MODAR, Inc., Natick, MA 01760 3ABB Lununus Crest, Inc., Bloomfield, NJ 07003 Hazardous organic wastes, including chlorinated hydrocarbons, in aqueous media containing salts can be effectively oxidized by treatment above the critical point of pure water (374 C, 221 bar). High destruction efficiencies may be achieved at low reactor residence times (approximately 1 minute or ,-=."r'==
less) for temperatures above 550 C. Under these conditions, no NO
.-s compounds are produced. The high solubility of organics and oxygen an the low solubility of salts in supercritical water make it an attractive medium for both oxidation and salt separation. This paper reviews critical technol-ogy components and operations required for commercial-scale development of supercntical water oxidation (SCWO). These include fluid handling and compression, heat exchange and recuperative heat recovery, reactor and salt separator design and materials considerations. In addition, a summary of fundamental research activities in the areas of oxidation reaction kinetics and mechanisms and solid salt nucleation and deposition is presented in the context of its impact on SCWO process development.

Oxidation carried out in a supercritical water environment at temperatures above 374 C and pressures above 221 bar (22.1 MPa) provides a viable method for the efficient destruction of organic wastes in a fully contained system. This patented process has been termed supercritical water oxidation, SCWO, and has been under commercial development for about the past 11 years by MODAR, Inc. (1-7). The process has also proven suitable for treatment of human metabolic wastes, and is being considered for use in life support systems on long-term spaceflights (8-11). A
relatively recent variation of SCWO involves carrying out the process in a deep well utilizing the hydrostatic head of fluid in the wellbore to help provide the necessary pressure level (see, e.g., Gloyna (12)).
The main objectives of this paper are twofold: (1) to review the status of above-ground SCWO technology from a process engineering perspective, and (2) to review fundamentally focused research on reaction kinetics, phase equilibria and solid salt separation critical to understanding the chemistry and phase behavior of reactions carried out in the SCWO process. The effectiveness of SCWO for treating a wide range of waste stream compositions will be reviewed. The status of development of SCWO as a commercial-scale process along with a discussion of remaining technical issues and critical sub-process elements will also be presented.
0097--6156/93/0518-4035$11.50/0 1993 American Chemical Society :I ~7 EMERGING TECIINOLOGIES IN IL"ARDOUS WASTE MANAGEMENT III
Economic predictions for SCWO have appeared in the literature (for example, see Thomason and Modell (6); Stone and Webster Engineering Corp. (13); and Modell (3,14)). Because of the evolving nature of the technology and the inherent uncer-tainties associated with orders-of-magnitude scale-up from pilot-sized units to commercial-sized systems, these studies should be viewed with reservation. For these same reasons, we have decided not to include economic projections in this paper, but rather to focus on engineering technology and basic supporting research.
Earlier reviews of SCWO technology by Freeman (15), Modell (3) and Thomason et at. (5), while providing important basic process engineering material, need to be updated with respect to current process development and fundarnental research on SCWO. A more recent paper by Shaw et al. (16) introduces several aspects of research related to reaction chemistry in supercritical water. It is our intent in this review to provide readers with a comprehensive listing of published papers, patents, and reports on various aspects of the technology.
The supercritical water oxidation (SCWO) process brings together water, organics, and oxygen at moderate tem)peratures (400 C and above) and high pressures (about 25 MPa). Under these conditions, a single fluid phase reaction system exists where many of the inherent transport limitations of multi-phase contacting are absent.
The temperatures are high enough to induce spontaneous oxidation of the organics, and the heat of reaction raises the mixture temperature to levels as high as 650 C.
Above about 550 C, organics are oxidized rapidly and completely to conversions greater than 99.99% for reactor residence times of 1 minute or less.
Heteroatomic groups, such as chlorine, sulfur and phosphorus, are oxidized to acids which can be neutralized and precipitated as salts by adding a base to the feed. For aqueous solutions containing between I and 20 wt% organzcs, supereritical water oxidation could be more economical than controlled incineration or activated carbon treatment and more efficient than wet oxidation (6), With appropriate temperatures, pressures, and residence times, organics are oxidized completely to carbon dioxide, water, and molecular nitrogen, without formation of NO,, compounds or other toxic products of incomplete combustion. Modell and co-workers (17) also destroyed problematic polychlorinated biphenyls (PCBs) and DDT at greater than 99.99% efficiency without formation of dioxins. Cunningham er al. (18) and Johnston et al. (19) oxidized synthetic pharmaceutical and biopharmaceutical wastes and achieved > 99.99 %
destruction of total organic carbon and > 99.9999 % destruction of thermophilic bacteria.
Oxidation in supercritical water is not limited to aqueous organics. Biomass, sewage, and soil can be slurried and fed to the reactor as a two-phase mixture.
Wastes with large particles or high solids content may need to be homogenized prior to treatment.' In principle, any mixture of organic waste that can be pumped to high pressure is treatable by SCWO. Precipitated salts and other solids can be removed from the product stream, providing a clean, high-temperature, high-pressure energy source consisting almost entirely of COZ, H20, and N. Heat can be recovered from the treated process stream and used to preheat the fee~, or the stream can be used to generate steam for direct process use or electric power generation in a high-efficiency Rankine cycle. The heat of the oxidation reaction is thus partially recoverable and can be used to offset the cost of treatment.
One of the main attributes of SCWO is its ability to rapidly and completely oxidize a wide range of organic compounds in a reaction system that meets the concept of a "Totally Enclosed Treatment Facility". Dilute aqueous wastes ranging from I to 20% organic content are particularly well-suited to SCWO processing. The scale of application is also adaptable, from portable benchtop or trailer-mounted units treating 1 to up to several thousands gallons of toxic waste per day, to large stationary plants capable of processing 10,000 to 100,000 gallons per day of waste with 8 to 10%
organic eontent. In the present designs, additional air pollution abatement equipment 3. TESTER ET AL. Supercritical Water Oxidation Technology is not required.
Nonetheless, solids removal and storage are necessary, and water effluent polishing units incorporating ion exchange may be needed to remove small concentrations of dissolved metal ions. Major drawbacks of SCWO are the hi h pressures required (>230 bar) and the fact that corrosion at certain points in tte process is significant. For some wastes, solids handling can also pose difficulties.
Properties of Supercritical Water In the region near the critical point, the density of water (shown in Figure 1) changes rapidly with both temperature and pressure, and is intermediate between that of liquid water (1 g/cm3) and low-pressure water vapor (<0.001 g/cm3). At typical SCWO
conditions, the water density is approximately 0.1 g/cm3. Consequently, the properties of supercritical water are quite different from those of liquid water at ambient conditions, particularly those properties related to solvation.
Insight into the solvation characteristics and molecular structure of the aqueous system can be obtained by experimental measurements of dielectric constant, ionic dissociation constant, and Raman spectral emissions in passing from the subcritical to supercritical regions. Figure 2 shows that the static dielectric constant of water at 25 MPa drops from a room-temperature value of around 80 to about 5 to 10 in the near-critical region, and finally to around 2 at 450 C and above (21-23). Along the same isobar, as shown in Fi~ure 2, the ionic dissociation constant falls from 10~
at room temperature to 10`18 in the near-critical regime and to 10-23 under supercritical conditions (24). Furthermore, Raman spectra of deuterated water in the supercritical region show only a small residual amount of hydrogen bonding (25,26). As a result, supercritical water acts as a non-polar dense gas, and its solvation properties resemble those of a low-polarity organic. Hydrocarbons exhibit generally high solubility in supercritical water.
Near the critical point, the solubility of an organic compound in water correlates strongly with density and is thus very pressure dependent in this region.
Benzene solubility in water is a good example (27,28). At 25 C, benzene is sparingly soluble in water (0.07 wt%). At 260 C, the solubility is about 7 to 8 wt% and fairly independent of pressure. At 287 C, the solubility is somewhat pressure dependent, with a maximum of 18 wt% at 20 to 25 MPa. In this pressure range, the solubility rises to 35 wt% at 295 C, and at 300 C, the critical point of the benzene-water mixture is surpassed. When the mixture becomes supercritical, by definition, there is only a single phase. Thus, the components are miscible in all proportions.
_~ . Other hydrocarbons exhibit similar solubility behavior near 25 MPa:
Binary mixtures of n-alkanes ((2-C7) and water become supercritical (and, therefore, completely miscible) at temperatures below about 370 C (27,29,30).
Supercritical water also shows complete miscibility with "permanent" gases such as nitrogen (31), oxygen and air (32), hydrogen (33), and carbon dioxide (34,35), in addition to small organics like methane (36). The loci of critical points of the binary mixtures containing water have also been reported by Franck and co-workers for the aforementioned organic substances and gases. Alwani and Schneider (37) have reported the phase behavior of aromatic hydrocarbons (including 1,3,5-trimethyl-benzene and naphthalene) with supercritical water. All of the compounds studied to date are completely miscible with water above 400 C at 25 MPa. Franck and his research group have also extended earlier phase behavior information for binary systems to include phase equilibrium data for ternary systems containing salts such as NaCI, CaC12, and NaBr (36,38,39).
In contrast to the high solubility of organics, the solubility of inorganic salts in supercritical water, as shown in Figure 3, is very low. Many salts that have high solubilities in liquid water have extremely low solubilities in supercritical water. For example, NaCI solubility is about 37 wt% at 300 C and about 120 ppm at 550 C
and 25 MPa (44); CaC12 has a maximum solubility of 70 wt% at subcritical temperatures, /c~' .__ ,.,. .. ~ . .' .. ... ........,.. . . ,.....,,..,.._.. ... . ..r.õ~.-...~.
,. . ~ . ,... _ ~ EMERGING TE-CIINOLOGIF.S IN IIAZARDOUS WASTE MANAGEMENT III
oQ

... vo rn O
o ~
H. c Vapor-Liquid Reglon = $~ 5~0 I.QQ~~,"l.V~ .
00o K mc~
O .t 00 Figure 1. Pressure-Temperature-Density Behavior of Pure Water. CP
denotes the critical point; the vapor-liquid region indicates conditions under which two phases are present. Density calculated from the equation of state of Haar et al. (20).

--Temperature, C
Figure 2. Solvation Properties of Pure Water at 25 MPa. Properties shown _-_ aL - .17 _i - _. ... . . .w r. . .. . . _. . -3. TESTER RT AL, Supercritical Water Oxidation Technology

10.0 wt%
t Pressure = 250 bar NaZSO`

0.1 wt%

NaCi 100 ppm KC! ~~-CaC~
~ =
ppm U7 `
1 ppm SotublGty at 251C anC
1 ber in wt'K
CaC4 45.3 CaSO4 0.63 NaC1 26.4 Na1SO221.7 KCI 26.4 100 ppb CaSO4 10 ppb 1ppo Temperature ( C) Figure 3. Salt Solubility in Supercritical Water at 25 MPa. Data interpolated from: KCI-Jasmund (40); Na2S0 ---Martynova (41), Ravich and Borovaya (42);
CaCI and CaSO4-Martynova (41); NaCI-Bischoff and Pitzer (43), Pitzer and PabX (44); room temperature solubilities-Linke (45). At temperatures below 450 C, a dense NaCI bnne appears (KCI and CaCIZ may also form dense brines at some temperatures).

'~ ( . .. . . ... .._......,..... ,..~.. ..._..:;,:r=,....,....... ..... .
EMERGING TECIINOLOGIES IN IIAZARDOUS WASTE MANAGEMENT III

which drops to 3 ppm at 500 C and 25 MPa (41). The fact that inorganics are practically insoluble is consistent with a low dielectric constant for water of about 2 and an extremely low ionic dissoeiation constant K.,, of less than 10-22 at 500 C and 25 MPa. At the same time, supercritical water possesses high diffusivity (46,47) and low viscosity (46,48).
The combination of these solvation and physical properties makes supercritical water an ideal medium for' oxidation of orgarucs. When organic compounds and oxygen are dissolved in water above the critical point, they are immediately brought into intimate molecular contact in a single homogeneous phase at high temperature.
With no interphase transport limitations and for sufficiently high temperatures, Ianetics are fast and the oxidation reaction proceeds rapidly to completion. The products of hydrocarbon oxidation are COZ and H20. Heteroatoms are converted to inorganic compounds, usually acids, salts, or oxides in high oxidation states, which can be precipitated from the mixture along with other unwanted inorganics that may be present in the feed. Phosphorus is converted to phosphate and sulfur to sulfate;
nitrogen-containing compounds are oxidized to N2 with some N20. Because of the relatively low reactor temperature, neither NO,, nor SOZ is formed (49).

Process Flow Sheet Description There are basically two concepts proposed for SCWO; (1) an above-ground system (MODAR process), and (2) the below-ground system (sometimes referred to as the Oxidyne process). Both process concepts react mixtures of oxidant (oxygen, air, or hydrogen peroxide) with organic wastes with or without dissolved salts. The inherent difference between the methods'is the technique for achieving high pressure.
The surface system requires high pressure pumps or compressors, while the underground system utilizes the natural hydraulic head of the fluid contained in a deep well to provide a substantial part of the pressurization (50,51).
The critical steps of the above-ground MODAR process are depicted in the flowsheet given in Figure 4. While certain components and processing steps may vary somewhat depending on waste composition and treatment objectives, the general characteristics of the SCWO process can be subdivided into seven major steps:

(1) Feed preparation and pressurization (2) Preheating ~ (3) Reaction (4) Salt formation and separation (5) Quenching, cooling and energy/heat recovery (6) Pressure letdown and phase disengagement (7) Effluent water polishing Each of these is described in somewhat more detail below.

(1) Feed Preparation and Pressurization: Organic waste materials in an aqueous medium are pumped from atmospheric pressure to the pressure in the reaction vessel. Air can be compressed to system pressure and metered into the reaction vessel. Alternatively, oxygen, stored as a liquid, can be pumped to the pressure of the reaction vessel and then vaporized. In some cases, it may be advanta~eous to use oxidants such as hydrogen peroxide; however, the commercial utility of this oxidant is limited due to its higher cost (approximately 30 to 40 times higher than oxygen).
Feed to the process is controlled to an appropriate upper limit of heating value of 4200 kJ/kg (1800 Btu/lb) by adding dilution water or blending higher-heating-value waste material with lower-heating-value waste material prior to feeding it to the reactor. When the aqueous waste has too low a heating value, ~Z 2-3. TESTER Cr nl,. SupercriticaC Water Oxidation Technology O N~

LO
,~~

~~= > d L
S
aci a a qa N

Q. J

_ o -^-~-----~ ~a rn --------- o pG~ O
, ~ R1 0 r?

r C ~
......... E ~ ..
~x ~
¾O

F<liij4FiKIlj ~ ~

EMERGING TECHNOLOGIES IN IIAZARDOUS WASTE MANAGEMENT III
fuel such as natural gas ortuel oil may be added. Optionally, a combination of preheat by exchange with reactor effluent and fuel addition or preheat alone may be used. One should keep in mind that other flow sheet designs are possible where higher heating values may be desirable, such as for energy recovery.
When organic wastes contain heteroatoms such as Cl, F, P, or S which produce mineral acids upon oxidation, and it is desired to neutralize these acids and form appropriate salts, caustic is injected as part of the feed stream.

(2) Preheating: The feed stream can be preheated by cross-exchange with the hot discharge effluent. This promotes rapid initiation of the oxidation reaction and helps to optimize the overall plant energy balance by better heat integration.
Other preheating options are possible (e.g., see Thomason et al. (5)).

(3) Reaction: Mixing of the oxidant and organic waste streams with the hot reactor contents initiates the exothermic oxidation reacdon which heats the reacting mixture to temperatures of 550 C to 650 C, accelerating reaction rates and reducing residence times for complete destruction. A second stage reactor may be included in other designs to meet destruction requirements for highly toxic materials or to ensure complete oxidation of CO and NH3 (see Thomason et al.
(5)).
(4) Salt Formation and Separation: Because salts have such a low solubility in supercrit3cal water, their precipitation is rapid under almost shock-like conditions.
The higher-density solid salts separate from the reacting phase and fall to the bottom of the reaction vessel where they can be redissolved and removed as a concentrated brine or colleeted as solids and removed periodically. A small fraction of salt is entrained with the hot reactor overhead effluent.

(5) Quenching, Cooling and Energy/Heat Recovery: The gaseous products of reaction, along with the supercritical water, leave the reactor at its top. In other design flow sheets a portion of the supercritical fluid may be recycled to the oxidizer by a high-temperature, higher-pressure pump. The reactor effluent (other than that recycled), consisting of supercritical water, Carbon dioxide, a small amount of entrained salt and possibly nitrogen, is first mixed with cold recycle fluid to redissolve the salt and then is further cooled to be discharged at atmospheric conditions.
Excess thermal energy contained in the effluent can be used to generate steam for external consumption to produce electricity at high efficiency or for high-temperature industrial process heating needs. For larger-scale systems, energy recovery may potentially take the form of power generation by direct expansion of the reactor products through a supercritical steam turbine. Such a system would be capable of generating significant power in excess of that required for air compression or oxygen pumpin; and feed pumping. For very dilute aqueous wastes, it can be more economical to use a regenerative heat exchanger to preheat the waste than to add supplemental fuel.

(6) Pressure Letdown and Phase Disengagement: The cooled effluent from the process separates into a liquid water phase and a gaseous phase, the latter containing primarily carbon dioxide along with oxygen, which is in excess of the stoichiometric requirements (and nitrogen when air is the oxidant). The separation is carrmed out in multiple stages in order to minimize erosion of valves as well as to maximize the separation due to phase equilibrium constraints.
(7) Effluent Water Polishing: Because of the corrosive nature of supercritical brines and the fact that heavy metals are present in many waste streams, trace P_ 4f 3. TCSTGR ET AL. Supercritical Water Oxidation Technology metal concentrations (e.g., Cr, Ni, Zn, Hg) will appear in aqueous effluent streams from SCWO (9,52). Consequently, a polishing step involving ion exchange or selective adsorption may be needed. This would be particularly' important in applications where recycled process or potable water is required.

For a discussion of the below-ground SCWO process, readers are referred to the following papers: Gloyna (12); Gulf Coast Waste Disposal Authority (53);
Stanford and Gloyna (54); Smith and Raptis (55); Smith (56); and Smith et al. (57). One of the most significant conclusions of the Stanford and Gloyna (54) paper on the performance of the below-ground process is that the energy savings due to avoidance of high-pressure pumping is more than offset by other losses, including heat loss to the surrounding rock formation and energy requirements during startup. Such losses suggest that well depths should be minimized.

Application of SCWO to Waste Treatment The SCWO process can be applied to a wide range of wastes containing oxidizable components. Details are provided by Thomason et al. (5) and Modell (3) and are only outlined here. Although initial development has been for aqueous wastes with 1-wt% organics, the process can successfuliy treat wastes in which organic concen-trations are as low as 0% or as high as 100%. Concentrated organic wastes and dilute aqueous wastes are frequently available at the same site and can be blended to provide a feed with the appropriate heating value in the 1-20 wt% concentration range.
With proper high-pressure pumping systems, sludges and slurries become good candidates for treatment and can be oxidized with high destruction efficiencies. While many organic solids will also dissolve in supercritical water, the initial partial oxidation to fragmented, lower-moleculaz-weight compounds is normally very fast at typical SCWO processing temperatures, so the need for an intervening solvation step is preempted.
Another application involves remediation of contaminated soils, as found at many federal Superfund sites. Bench-scale testing has shown that hazardous and toxic organics can be extracted from the soil and simultaneously oxidized in a SCWO
reactor (5). The process would continuously feed a slurry of the soil in water (contaminated groundwater or recycled process effluent water) to the SCWO
reactor system. The effluents are clean water, COz and N2, and soil that is both sterilized and free of organics.
~ For very dilute wastes (i.e., below 1 wt% organics), activated carbon adsorption or biological oxidation is often an effective treatment method. The major cost of carbon treatment is the cost of regenerating -the carbon. The carbon loading, in turn, is directly related to the concentration of organic contaminant. Hence, the cost of waste treatment is nearly proportional to the organic concentration and usually becomes prohibitive for wastes containing more than 1% organics. Biological treatment systems, on the other hand, become poisoned and often cannot be sustained for many complex waste mixtures or wastes with organic concentrations of 1% or more.
Incineradon, on the other hand, is usually restricted for economic reasons to waste streams of relatively high organic concentrations, To achieve high destruction efficiencies for hazardous and toxic wastes, incineration is performed at temperatures as high as 900-1300 C (1700-2400 F) and often with excess air as high as 100%.
With aqueous wastes, the energy required to vaporize and heat water to these temperatures is substantial. If the waste contains 25% organics or more, there is sufficient heating value in the waste to sustain the incineration process.
With decreasing organic content, the supplemental fuel required to satisfy the energy balance becomes a major cost. Furthermore, incineration is also being regulated to restrict stack gas emissions to the atmosphere. Extensive equipment must now be used . . . .. . . . . . . -... .":t= = ....~.r. . I... _ .. . . . .

~4- EMERGING TLCIINOLOGIIrS IN IiAZARDOUS WASTE MANAGEMENT.1I1 downstream of the reaction system to reinove NOX, acid pses, and particulates (fly ash) from the stack gases before discharge. The cost of this equipment often exceeds that of the incinerator itself.
In the range of concentration of 1 to 20 wt% organics, both wet air oxidation and supercritical water oxidation have certain practical and potential economic advantages over controlled incineration or activated carbon treatment (S). In wet air oxidation, can-ied out typically at temperatures ranging from 200 to 300 C, destruction of toxic organic chemicals (e.g., chlorophenols, nitrotoluenes) can be as high as 99.9%
with adequate residence time but many materials are more resistant (e.g., chlorobenzenes, PCBs). Total COD (chemical oxygen demand) reduction is usually only 75-95% or lower (58), indicating that while the toxic compounds may undergo satisfactory destruction, certain intermediate products remain unoxidized. Because the wet air oxidation is not complete, the effluent from the process can contain appreciable concentrations of volatile organics and may require additional treatment such as bio-oxidation. Supercritical water oxidation typically achieves greater than 99.99%
reduction in total organic carbon (5), so SCWO offers a much more thorough treatment option than wet air oxidation. Thus, for aqueous streams which require high destruction efficiency and complete oxidation, SCWO may well be the method of choice.
Given current trends toward source reduction and waste minimization, there may be unique applications for SCWO as an integrated component in the manufacture of chemicals. For example, SCWO could be regarded in the same context as distillation with chemical reacdon, where in this case residual organics are chemically stripped out of a water solvent stream that is recycled continuously within the process.

History and Status of Development The supercritical water oxidation (SCWO) process has been patented for above-ground and for underground applications. Table I gives a listing of most of the relevant patents for both applications (related high-pressure wet air oxidation patents have not been included; see, e.g., Barton et al. (69) and Thiel et al. (70)). Most of the work published on SCWO is related to the above-ground surface system, and this consequently is the focus of our review. The earliest patent in this field is due to Dickinson (59). In his process, the oxidation reaction commences at conventional wet oxidation conditions, but the heat released by the exothermic reaction increases the process stream temperature to a supercritical level. Nonetheless, the above-ground MODAR process actually has its roots at MIT with an invention cited by Dr.
Michael Modell and co-workers (71) on thermal reforming of glucose under oxygen-free conditions in supercritical water. In 1980, Dr. Modell left MIT to develop SCWO
technology. He founded MODAR, Inc. in Natick, Massachusetts as a commercial venture to develop and market the technology. MODAR continues as a commercial leader in above-ground SCWO technology. Since 1986, Dr. Modell has pursued special applications of the technology, laboratory testing, and development services with a second venture called the Modell Development Corporation (or MODEC) located in Framingham, Massachusetts.
At the time of writing this review, an Austin, Texas based subsidiary of RPC
Energy Services, Inc. of Atlanta, Georgia, Eco Waste Technologies (EWT), is conducting research at the University of Texas Balcones Research Center (UTBRC) on SCWO technology. The work initially centered on the use of a shallow-shaft concept with Dr. Earnest F. Gloyna serving as principal investigator. The RPC
grant to UT was redirected to a surface study of SCWO and, in cooperation with UTBRC, EWT designed and constructed a 40 gph SCWO reactor that is currently being utilized as a test unit. The unit has been successfully tested on a variety of wastes and surrogate materials (Lyon, D., RPC Energy Services, Inc., personal communication, 1992). 2 &

2- No. 1998.060 /~ ~~QN~r k Study on a New Upgrading Process of Heavy Oils Combined with SAGD by Means of Hydrothermal Treatment A. Kishita, H. Kamimura, C.X. Hong, and H. Enomoto,Tohoku University, Sendai, Japan; T. Moriya and Y. Saito, Tohoku Electric Power, Sendai, Japan; T.
Sugiura, Japan Petroleum Exp(oration,Tokyo, Japan; and K. Ohno, Japan National Oil Corporation Technology Research Center, Chiba, Japan Abstract reaction. In this combined process, tttc high temperature wastc f= urrctum<rrrlu! staclies on the hVC!!'OthC'rmG! (GC111ClthCrlllul) water can be utilized as steam for injection.
rrur kirr>; o/ hirrrmcrr in the ,'crrrgc oJ strpercruicnl water were The function of water in hydrothermal reactions had been ew rwcl our to e(u, i/i= rf,c, renction conclirior,s anc! to verify the studied, and it had been found by hvlR analysis that polymers l,n=/i,ninur ~ rc:~rrlt Jor- ch=veloping ci new on site trpKrcrclinK such as vuleartized rubber were easily cracked to low rnolecu-rc=cfuur/og v ReA rrlts fuurlci ure: Birrtmens= +c=ere easilr converted lar hyctrocarbons with the sttpply of ttydrogen t'rom w=ater' and trr liglu nil.y. rrith sinrultuneorec recltrc=tinn of'srrlJirr to ecr. 1/1, desulfurization.'The preliminary investigation on the upgrad-r urur<hrrnr to !t)`.%, and c.=oke procluctiun to 10;, The reaction ing of bitumen by alkati under hydrothermal reaction has been cu,rclitiwt cf ?03 K reaction tempercrrr.trcr und 15 min reacti0n carried out without using hydrogen gas.3 time rc'ith 0.1 A1 KOII solrtticrn at 25% n'cuer louding is crnouglt At the extended stage of the study, a continuous flow reac-tn l,ruchr(x .s'uJficic=,uls liglrt oils Jbr pipelirre transportation, tor was developed. In this paper, results obtained with the eon-c,rul rlrcr /hrclucrtiorr vTvi(-wuter ratio in the rcrnge of 0,3-1,0, tinuous flow reactor are described, as well as summarizecf hY)/1 rcufcerxrcrtir r irr tlte range of 0.03-1.0 Al und nater results of fundamental studies with batch-type micro-auto-tnucling irr thc= rctrrgu o/ 20-30% cloes not give s'eriotrs irfltr- claves.
;vr~ e On /1K' 11(r)l.l' Uf thv ,-e.s'r(lrs ahove, a continttort.s' flow reac=tor j t) .i h-'rl c=rrpcu its %,= r+rgradinK hitrrnrerr was oper-crted ancl /rrtrhrr,rr=rrtal rrnrl ir>zh+,rtamt cluter fior the nevr hruces=., ,L'E:rE
Optimization of Hydrothermal oh,rrirrrd Reaction Conditions In the It:'cbotltermu/ cracking. neither hYclrogen gu.s' na-:r((rlt:~r i~ rrsecl, nncl nr rhe crlkcrii !>Ydrorher-mal cracking, rrei-Experimental tlwr CC), nirr-1 f;S is pruchrc;ec( :? cornhined s)=stem svith SAGD In order to clarify the reaction conditions, batch-type auto-c cur rrrili_ the wcrstv water crs sYeunr fnr injection. claves of 45em' in volume were used. -I'he autoclave and induction fumace used for heating are shown in Figure I.
In each run, a cenain amount of bitumen (5 g in most cascs) was put into an autoclavc with a certain amount (9-18 g) of Introduction alkaline aqueous solution (0.03-10 M) and a stirring ball Ro.7entfy. Steam Assistect Gravity Drainage (SAGD) process tnade of the same alloy as that of' inner vessel of the auto al+p~areJ in Canada as an economically feasible recovery claves Inconnel 600).
The autoclave was inserted horizontally rnk:thc,d ot' biturnen production from oil sand deposits. 'f'he at the center of the furnacc and was heated to a reaction tem prc.xluct urt of bitunten in Alberta is expccted to increase to 1.3 perature (673-723 K) at the heating rate of 40/min. The con-miiifon b.d by 1-005. On the other hand, this may cause con- tents of the autoclave were stirred with the stirring ball by t::rn b"ause ol' the shortage of condensate for dilution of tain rocking the furnace. After keeping the teniperature t'or a cer-b;lum n For pipLline transportation. Therc is oF no doubt that tim~ (reaction time), the autoctavc was taken out of the clc%~~lopn,ent irf new on site upgrading technologies are key furnace and was cooled to the room temperature at the similar cooling f>r tho sust rinahle growth of heavy oil exploration industrics. rate as ihe heating rate. The oil product was separated frorn the water in a sepratory funnel and fractions ot' product In tlir SA(C) operation, a miittrre of biturnen and hot water were rncasurect.
Toluenc was used to wash the inner wall of i; continuou;ly recovered, so that the mixture recovered can the autoclave to ensure total recovery.
bL I'ed into a reactor to upgrade the bitumen by hydrothermal ;z-7 +dr , rututional ~ iscometer was ttsed for measuring the viscos- Regarding the gas composition: H, and CH4 were pro-i:v of oil pro(Iucts at 303 K. Molecular .veight distribution of duced, but COZ and H2S gases did not exist when alkali solu-u;!; was mcasur.d by 1-IPLC which was calibrated with poly- tion was used.
Howcver, when pure watcr or dilute alkati ;rvrcnws ofkrwwn molecular weight. Sulfur and nitrogen con- sulution (0.03 M) was used, COZ and H,S as well as I{ and mnt> were analyzed with a CNS analyzer. light oil CH4 were produced.
comE~ot;c~nts wt:rc identified by with GCMS and GC/AED
iAtvrnic E:mis,ion Detector), and metals werc analyzed by 1( 1'.
lwo kinds ot's:nnples ot'bitumen were used: one was pre- Desulfurization and Metal l,rt:i; in I,ur ;uburutury by cxtraItiun Il-um Attwbttsca uil sturcls Removal itti tolu~ne and subsea,uent evaporation of toluene (BITU-Mf.N 1). Anottter sample was an Athabasca bitttnten as In hydrothermal cracking, desulfurization and metal removal r~.ci~ed which had been already separated from sands (BITU- also occurs.
Figure 6 shows desulfurization at various reaction \11i\ 11). For fundantental studies: BVfUMEN I was mainly temperatures. The sulfur content of oil product from BITU-t:>~'d, ttnd B1TU~.1FiN II for continuous treatment. As shown in MEN I at 703 K decreased to 2.0% from 4.5% (original), but lable I, propcrtie, ot' these bitumens are not much difl'erertt, for BITUMEN

11 at the same reaction condition a small reduc-7ut sli-Ettk t.lit't-,rent results were obtained, tion from 4.8-3.2Uio occurred. This may be due to the difler-ence of structure of sulfur compounds in both bitumen samples. It has also been shown that the structure ot' sult'ur compounds has large influence on the desulfurization, as is R e 5 u lt s a n d D i s c u s s i o n s well known in the thermal cracking, though desulfurizatior, Products reactions proceed at lower temperatures in hydrothermal cracking than in thermal cracking.' It has also been shown that Ir, all runs, bitumen was eonverted to much lighter oils. Figure in hydrothermal reactions the drastic reduction in desulfuriza-2 shows the reductiort of viscosity ot' oil product with reaction tion occurs in first 5 min, and after first 5 min the inFluence of :empertuure for a 15 min reaction. Although there is a differ- water loading appears, but 30% of sulfur still remains even in r,tcc uf vi:co,ity between both biturnens, the reaction condi the case of 40%
water loading for BITUMEN II?
;;t n of 703'K for reaction temperature and 15 min for reaction Mtc with I h1 KOH solution at 20`%'u water loa(iing is enough In order to investigate the influence of oil-water ratio in the ) prut.luce strtticiently light oils for pipeline transportation. reactor on the desulfurization, many runs were conducted in \t'tstcr loaclin5 is delined as the ratio of' the volume of water the runge of the ratio of 0.3-1.0, but no influence was found.
.-,tdcd into the reaction charnher to tttc volttme of reaction The original vanadium content of 160 ppm for BITUMEN I
. harnher. Figure 3 shows the viscosity reduction with the reac- was reduced to 12 ppm by the 15 min reaction at 703 K.
w:~ tirne a, ~% ell as ttie water loadinb. Drastic reduetion in vis-u> uccurs in tir,t 5 mirt, i'ollowcd by slow reduction ;rt'~.rw:rrd. lm:rea,e of water loading, that is water density, ;nar hinder the fa,t cracking.3 Figure 4 shows that the varia- Summary of Reaction Conditions uun of KOFI concentration (loes not influcnce the viscosity of As described above, it was found that bitumens was easily o,l pruduced. converted to light oils with simultaneous reduction of sulfur FiRUre 5 shows tlie fraction of'prodttets by weight at (iiffer- and vanadium, with less coke production. The reaction condi-crrt rcac::ott ternpQr'atures t'or BITUMEN 1. Fractiotis of coke tion of 703 K
15 min reaction time with 0.1 M KOH solutiun tulucne-in>uluble rnatcrial), and unknown material increase with 25 percent water loading is enaugh to produce sufht-,, ith rncre;asing ternrerature. But, about a half' of the fraction ciently light oils for pipeline transportation. The fluctuation of' vt u;:;nown i, e,titmucd to be lightcr oil components, which oil-water ratio in Ihe range of 0.3-1.0, KOH concentration in ,:re c~acuattrd in evaporating tuluene used as the extractant. the range of 0.03-1.0 M and water loading iti ttie range of Z0-l hi, conciu,,ii>n is tlie basis of the estitnation of the fraction of 30%
does not seriously inftuence the reaction.
(CiC. 11E)) and water-sotuble organic compounds (TOC) ,Imck: iud t;t the unknown. Therefore, it can be sttid that the trt:cnun of asphaltene (n-pcntane-insoluble but toluene-solu-h.c nt;ttcri;tll from thc original oil is roughly equal to those of Upgrading of Bitumen in a uthers th.m malten (n-pentane-soluble). In other words, the Continuous Flow Reactor fraction of malten does not change much before and after the react: on. Frtction ot'coke prodttced at 703 K is ca. 8'%,, w=hich Continuous Flow Reactor System , i;=:uch 1-,s, than that in thermal cracking. '{'his may iniply Figure 7 shows schematically the continuotu flow reactor sys-=P nt hydroven rs supplietl frotn water andi=or the water prevents tem. The reactor is made uf Hastelloy C-276. Its inner diame E u;yn~~ri~ation. ter is 50 tnm and the length is I m(volume is CA., 2 liters).

f he rvactur can be set either vertically or horizontally, but in 2. Another reason is that the temperature of the fluid was tht: present study it was set verticaliy. It can be equipped with about 40 C
in the cullector. This temperature niay be high i; stirrer and can be used up to of 800 K and thc pressure of 50 cnough for very light coniponents to escape.
ml',r T'tie reactor is hcirted with clectric furnace. Temperatures The sulfur content of oil product from the contintrous reac-irr the reac.=tvr are rncasurecf w=ith thermoeouples and the pres- tor is lcss than that of the batch-type autoclave. Table 4 shows surc is cuntrolled with a back pressure regulators, the sulfur content uf' original bitumen and each product. The Alkali solution and bitumen are preheated in the pipes to amount of sulfur in the oil products, including the residual oil the reactor. I'hey are separately fed at the bottom of'the reac- recovered from the reactor as the mixture with coke, tor and flow out from the top of' the reactor. Products and dccreascd to less than a half. The sutfur content of coke is as ;,tcr anr cullcct~d t i;h a frau:tion collt:ctt,r. itigh as S.2%, which means that 17.7`Y oftutal strlfur goes irito the coke. Unknown quantities of sulfur tnay be in the w<uer phase.
The nitrogcn contents of both oil products are sirnilar and Experimental Condition and only10 r ofthe nitrogenw=asremovcd.
Procedure 13I fl:ME\ 11 tkas used in this experirnent. Experimental con-ditions were set based on the results of fundaniental study d:scribcd abiwc. These cunditiuns are show'n in Table 2. Run Recovery tinic i; the duration at which bittunen was t'ed into the reactor. Material balance in both the continuous reactor anci batch-l3rc;ttr, , as tnentioned latcr. coke furrned, (deposited on the type autoclave is shown in Table 5. In the batch-type auto-bottom of the reactor.) operation of the flow through reactor clave, very light hydrocarbons are also recovered, in the run titnr was less than 2 hours. Pressure was controlled to be with continuous reactor, a total of 1,073 g of BI'fUMEN It b:1tKti;en 35,40 MPa which corresponded to approximately was fed to the reactor an(i 77% was recovered as the oil prod-25';"t) of wtter loading. uct. Recovery of oil product from the continuous reactor is After the reactor was hcated up to the reaction temperature, less than that of the batch-type autoclave. The ditTerence is tlrr tlvw ul' pure water to the reactur t'ed was changed to the seen only in ttte asphalten fraction, which suggests that the ;;'kaline Solutiim. and the feed rate and the pressure were difference may be compensated by the residual oil and ad ustctl. Then bi(urncn w<;s injected witti readjustment of the increased coke, Increased coke may be caused by cleposition prersurr of heavy cornponents of oil on the bottom and sides ot' the Ali uil ar.c1 wator solution flowing out of the reactor were reactor, so that the f'eed of bitumen at a higher position of ver-coileeteci The pri)dtrct remaining in the reactor was collected tical reactor niuy recluee the amount of coke and residual oil. It au the ri;siduc atler tttc system was cooled to the room temper- sltould be noted that the residue, the mixture of residual oil :ure The residue was the mixttu-c of residual oil and coke. anct coke, can easily flow at high temperature.
The re,idu;:rl oil was extracted with toluene for measurement and anr~lysis.
Metals Table 6 shows the distribution of vanaditnn antl nickel in the products as well as their total amount in the bitumen fr;d to the Results and Discussions reactor. uanadium in the oil product decreased to ca.
10%.
65% was found in the soiid phase with coke anct 20'%, was in Oil Products thewastcwater.
(z:blc 3 sho s th~ pruperties of uil products obtained from the f towever, the total amount of nickel recovered incrcased : r,ntinuau.. flrxti reactor and the batch-type autoclavc. Com- tremenciuusly increased. Most of nickel was found in the solid par,sun shu~~:. that rhe viscusity of oil product frurn thc con phase with coke and little in the waste water, This means that ;lnuMr., rc;rclnr i~ highrr tlruri the batch-type autoclave. increased nickel carne from the tubing system before enterinb I'irvr nray bQ twu reastrn : thc reactor. Our experiencc says that it is necessary to often I In thc b:rtch-type autoclave, all components ot'oil are sttb- exchange the gasket made of Inconnel 600 usecf at ttte connec-jcct to the reaction for the whole reaction time. However, tion of water line to the reactor.
in the continuous flow vertical reactor, light oil compo-rrents that arc produced are separated and flow up and out ot'tttc rcactor without furthcr cracking. "['herefore the oil nrudurt, in the case of continuous reactor contains less amount of very light components.

Conclusions References FunaamCtual sttrdies ort the hydrothertnal cracking of bitumen 1. Nakahara, M., Tcnnoh, T., Wakai, C., Fujita, E., and r;r thr ranvc ol'supercritical water wcre carried out to clarify Enonioto, H, 1997, 13C-NMR Evidence for Hydrogeti r~'a~tMn conditions and to verify the preliminary results for Supply bv Water for Polymer Cracking in Supereritical dcticioping a new on sitc upctrading technology. Water, Chemistry Letters, pp.
163-164.
A continuous flow reactor lix upgrading bitutnen at the rate 2. Tennoh, T., Fujita, E., and Enomoto, H.,1996, Character-of 0.' b d was operated. Fundaniental and important duta for istics of Alkaline Containing Hydrothermal Reaction th~ ac\~ process wcre obtaincd. under St!percritical Conditions on Liquefaction of a Vttl-I! !o..'d hr cmpha~i~.od tha! in the hydrothermal crackine, canized F.PDM
Rubber and [ndustrial Application of the r itlic r hvtlro.;en gas nor catalyst is used, and in alkaline Resultant Oily Materials, J. of the Mining and Matcrials hydruthcnnal cracking, neither CU7 nor H,S is produced. A Processing Institute ofJapan, 112. 13, pp. 941-946.
ca!nhined system of' alkaline hydrothermal cracking with 3. Kamimura, ti., "Cakahashi, S., Kishita, A., Moriya, T., ti;N(;!) can utilizc the waste water as steam tor injection. Hong, C.X., and Enoinoto, Hõ August 1998, Upgrading of Bitu!nen with Supcrcritical Water for a Sysicm Com-bined with SAGD, To be presented at Sympositnn on Fuels for the Year 2000 and Beyond, Am. Cheni. Soc., Division of Fuel Cheniistry, Boston.

'3u -jpsl BiRimen I Bitunlen i!
Viscosity (mPa:'is) >2,0x 105 2.8x 104 ineasured at303" K

('ontent u( Element>
C 80.3 84.0 S 4.5 4.8 \ 0.30 0.32 Content of Metals (ppm) Ni 57 64 Table 1: Properties of Bitumens Continuous Batch*
loed BITUMF.N II 1073 g 5.0 g product /u M) oii product 76.9 84.0 (malten) (71.9) (72,0) (asphalten) (5.0) (12.0) resiciuc coke 10.6 8.0 residual oii 5.7 -(mul(cn) (1.7) (asphaltcn) (4.0) inor-~anic < 0.1 -unknoNN nNas, water soluble) 6.8 8.0 '0.1 M KOH, 703 K, 20"/0, 15 mtn.

Table 2: Experimental Conditions In the Case with Continuous Flow Reactor '-3 ( IWO

content weight (g) % by weight fecd G31 ( lJl=9E:.ti I! 4.8 51.5 100 (malten) (4.0) (34.3) (66.6) (u>phaltcn) (8.0) (17.2) (33.4) prbduct oil procluct 2.6 21.5 41.7 (+r,alten) (2.5) (19.3) (37.5) (ttsphalten) (3.3) (2.2) (4.2) 1 resicluc coke 8.2 9, t 17.7 resiauul oil 5.2 3.1 6.0 (malten) (2.5) (0.5) (1.0) (asphaltcn) (5.2) (2.6) (5.0) Lurknown 17.8 34.5 ~..

Table 3: Properties of Oil Products Run tirne (min) 120 Reaction tcmpcrature (K) 708 Pressure (MPa) 35-40 Feed rate (cm3/min) 0.05 N1 alkali solt+tion 22 bittmien 8 Table 4: Distribution of 5ulfur In the Bitumen and Products I z 4,e-continuous btttch'' Viscvsity (mPa-s) 40 25 Contcnt of Elements (wt%) C 82.7 82.3 S 2.6 3.2 N 0.29 0.30 '01 M KOH, 703o K, 20'/0, 15 min.

Table 5: Material Balance After Reaction Va Ni f"ecd BITUMEiN II 163.0 mg 69.0 rng product Mg (`%o) mg oil product 15.3 (9.4) 60.2 rcsidue oil 1.7 (1.0) 4.8 coke 106.0(65,0) 489.0 water ;oluble 33.3 (20,4) 8.0 -unknown 6.7 (4.2) Table 6: Contents of Vanadium and Nickel '3 3 I~pe f-5 Figure 1: BatchType Autoclave (Top) and the Induction Furnace (Bottom).
1:Thermocouple, 2: Chamber, 3: Stirring Ball, 4: Inner Vessel, 5: Autoclave H BITUMEN I
B BITUMEN II

H

H
H
i Reaction temperature (K) Figure 2: Viscosity of Oii Products at Various Reactlon Temperatures (Reaction Time: 15 min, 1M KOH, 20% Water Loading) 4~

A BITUMEN I 40% water loading J BITUMEN I 30%
H BITUMEN 120%
B BITUMEN II 20%

A

E
~ ~ B R
o H
V
> 10 H
t Reaction time (min) Figure 3: Effect of Reaction Time on the Viscosity of Oil Products (Reaction Temperature: 703K, 1 M KOH ) H BITUMEN
B BITUMEN II

B B B B
r H
a t0 H
a H
V
~

Concentration of KOH (M) Figure 4: Influence of KOH Concentration on the Viscosity of OII Products (Reactlon Temperature:
703K, Reaction Time: 15 min, 20"/a Water Loading) I ~ /
.dr [] Gasandwatersolubleorganlccarbon Malten Asphalten Coke OD \ `\
\ ~\
A
Q~
a o 40 Reactant 673K 703K 723K
Reaction temperature (K) Figure 5: Fraction of Products (BITUMEN I; Reaction Time: 15 min,1M KOH) " H
r u 3 B
c ei 2 H H

Reaction temperature (K) Figure 6. Sulfur Content of Oil Products at Various Reaction Temperatures (Reaction TIme:15 min, 1 M KOH, 20% Water I.oading) Reactor T BPR

3rd Separator Cooling Un it Heating Block 2nd Cooling Unii 1st Cooling -_-__. Unit Bitumen =+Coolant Tarik Pump1 - relief valve ----=-~--------1T, ~-~~

Alkali Drain Solution Sample Collector Tank Pump2 P: Pressure transmitter T: Thermocoupie BPR: Back pressure regulator Preheating zone Figurce 7: Continuous Flow Reactor System '3 7 I-D

Annex A: further example embodiment of invention relating to "Upgrading of bitumen using SuperCritical Wet Oxidation" - this embodiment having a focus relating to energy & water recovery Supercritical water exists at temperatures and pressures above the critical point of water (of 221 bar and 374 C). The physical chemical properties of supercritical water is extensively described in prier art, relevant properties to this application can be summarised as follows.

= Supercritical water has unique solvent properties in that hydrocarbons and gasses are 100% solvable and inorganic (salts) are insoluble and will precipitate out.

= When oxygen is dissolved in supercritical water and comes in contact with organic material (i.e. hydrocarbone) it results in a spontaneous combustion.
This combustion is often termed SuperCritical Water Oxidation (SCWO) = Supercritical water has unique chemical properties in that it possesses a certain reforming activity it can hydrolyse cellulose, it can act as a reducing agent (hydrogen donor) in hydrocarbon cracking and reforming.

There exists numerous references to processes for cracking, desulfurizing, denitrifying, demetalating, and generally upgrading hydrocarbon or coal fractions by processes involving supercritical water. As early as 1976 McCollum et al.(US-Patent 3,983,027) described a supercritical water process for upgrading coal in absence of hydrogen, carbon monoxide or catalysts. process patents have been filed covering various aspects of coal and bitumen recovery and upgrading by application of supercritical water.
The specific application of supercritical water for upgrading bitumen is extensively described by Kamimura et al (Fuels for the Year 2000 and Beyond, Am. Chem. Soc Division of Fuel Chemistry, Boston, 1998) and by Berkowitz et al, (USPTO 20070056881).
Kamimura et al. has also filed a patent (CA 2,220,800) which specifically addresses the application of supercritical water to the SAGD-process.

The SCW Process The SCW process of the present invention is in narticular distinct from the respective Kammimura, Berkowitz and any other related processes in that carbon capture and energy recovery is an integral part of the bitumen recovery process.

The current process integrates elements of the following five processes into the SCW-concept:
1. SAGD (Steam Assisted Gravity Drainage) process for bitumen recovery (app.1) 2. Super-Critical-Water-Oxidation (SCWO) process 3. Super-Critical-Water (SCW)-reforming and upgrading 4. Super-Critical-Partial-Oxidation (SCPO) for CO generation 5. Super-Critical COZ used for deasphalting Bitumen conditioning and fractionation The current process comprises a closed loop, as illustrated in Fig.lb (below),where live steam is injected into the bituminous formation (1) to facilitate mobilisation of the bitumen by gravity drainage and recovering at the surface as a hot bitumen-water (2) emulsion (SAGD). Said emulsion comprises generally one part bitumen per three parts water. The emulsion is diluted by one part upgraded oil product (3) and one part hot water (16), the purpose of the dilution is to reduce the density of the bitumen to facilitate gravity separation (4) of the water/bitumen dispersion. The respective phases is pressurized, water (4A) to minimum 222 bar to exceed the supercritical pressure of water, and bitumen (4B) to minimum of 70 bar which corresponds to the supercritical pressure of C02. The bitumen is fed into the Rose Process for de-asphalting and fractionation using supercritical C02 as solvent. Thermodynamic models (EOS) to establish optimum conditions mass-flows, pressure and temperature, for using C02 for bitumen fractionation is available. A description of the solvent properties of C02 and of the Rose Process. It should be noted that The Rose Process is extensively used for de-asphalting in refineries, where supercritical propane or butane is often used as solvent.
The residual asphaltene and resins (6) from the Rose Process is subsequently used as fuel and fed to the SCWO-reactor (17) and to the SCPO-reactor (26) for CO-generation.
The residual bituminous phase from the Rose Process (8) is heated over two consecutive heat exchangers (9) and (10) to a final temperature exceeding 374 C (the supercritical temperature of water).
Excess supercritical water is added to the bituminous stream (10A). Water will dissolve the bitumen and form a homogeneous phase and inorganic and ionic components will precipitate out of solution. The mixture is held at a specified pressure and temperature (exceeding the critical point of water) in the vessel (13A) for the required time to facilitate demineralization and sulphur removal of the bitumen to avoid eventual catalyst poisoning. Minerals and sulphur will precipitate and are removed by filter and/or liquid-solid-cyclone. The density of supercritical water is in the range of 0,1 g/litre which favours the use of G-forces (cyclone) for separation of solids. Hence cyclones should be considered at all stages in the process where solids removal from supercritical fluids is an issue.

Bitumen upgrading The bitumen mixture is fed to a catalytic reactor (12) for upgrading.
It is reported that bitumen upgrading in supercritical water, without catalysts, require 10-15 minutes reaction time. In order to successfully scale up this process to industry scale, the reaction time has to be reduced by a two orders of magnitude, to less than 10 seconds.
Traditional hydrogenation is generally classified as "heterogeneous catalyses"
where hydrogen and catalysts are dispersed in a hydrocarbon phase. Mass-transfer, i.e diffusion of substrates (hydrogen and hydrocarbon) into the catalyst site, is often the rate-limiting step in heterogeneous catalyses.
Catalytic hydrogenation of hydrocarbons, dissolved in supercritical water, is favoured by the fact that hydrogen, hydrocarbons and water comprises on homogeneous phase with low viscosity and high diffusivity towards the active catalytic site.
Alternatively the catalyst can be "pony tailed" to a hydrophobic group which promotes solubility in the continuous phase, - and consequently yields a "homogeneous catalyses" where mass-transfer is eliminated as rate liming factor.
It is therefore conceivable to design a plug-flow reactor for "homogeneous catalyses"
which would reduce the reaction time to say <10 seconds to meet the requirement for "primary upgrading" . The oil-product is cooled in a heat exchanger (9) against the feed.
The cool product will separate into two phases, oil (15) and water (16) in a gravity separator (14). The oil should now meet the specification for primary upgrading.

Hydrogen generation Hydrogen is generated (13) from CO by the Water-Gas-Shift -Reaction in supercritical water. The kinetics and mechanism of this reaction in supercritical water is well established.

Water-Gas-Shift-Reaction: CO + H20 p CO2 + H2 It is an equilibrium reaction, globally first order in water and carbon monoxide.
Continuous addition NaOH (26) will drive the reaction towards hydrogen generation, because COz is removed (precipitated) as NaCO3 Carbon monoxide generation Carbon monoxide is generated by Super-Critical-Partial-Oxidation (SCPO) . SCPO-reactors are commercial available from General Atomics CA USA. They are designed for CO-generation from organic waist material as a precursor for subsequent hydrogen production.

The residual asphalten from the ROSE-process (6) is used as carbon source in the SCPO-reactor, a sub-stociometric feed of oxygen from the favours CO-generation. The specification for optimal production is available from the vendor.

Super-Critical-Water-Oxidation (SCWO) Pilot scale SCWO-reactors are available from General Atomics CA USA and Turbo Systems CA USA. The mechanism and kinetics of SCWO is well established.

Residual asphaltene (6) from the ROSE-process is used as fuel.
The energy output from a SCWO-reactor is dictated by the hydrocarbon injection rate (6) and the temperature is controlled by the water rate (4A). A spontaneous combustion of the hydrocarbons results when a stociometric excess of say 1-5% oxygen is injected into the SCWO-reactor. When excess oxygen is injected, the combustion is normally complete, yielding only C02 and water. The flow from the reactor comprises C02 and water is split in three (18), one part going to holding vessel (13A) one to a heat exchanger (10) and one to steam generator (20).
Inorganic components (salts) are not soluble in SC-water, and will precipitate and removed by appropriate filters or cyclone.
C02 capture and steam generation.
The stream exiting from the heatexchanger (10) comprises C02 and water, is cooled to a temperature below the critical point, hence it will separate into two phases, the top-phase is liquid C02 is fed to the Rose-process (7). The bottom phase is hot water which is heated in a heat exchanger (steam generator) (20).Some energy is recovered as the water phase is expanded over a steam turbine (21) down to the required pressure and temperature for live steam injection (1) into the bituminous formation.

Claims