Abstract:
The invention provides a high pressure dynamic environmental chamber for analysis of solids in a liquid suspension in motion at pressures ranging from vacuum to 2000 bars or more and temperatures from −50° C. to 500° C., using a liquid and/or a gas phase as pressurizing medium. The chamber is equipped with an entry window and an exit window so that the suspension can be illuminated and analyzed, using X-ray Diffraction, Raman Spectroscopy, Infrared Spectroscopy, or other photon radiation. The concept of direct analysis of a solid in suspension in motion over a wide range of pressures and temperatures is an important aspect of this invention. This motion is useful for X-ray diffraction analysis of the dispersed solid material, because it allows for a continuous change in the crystallographic orientation of the solid phase with respect to the primary X-rays while keeping the solid material in suspension.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No. 61/459,494 filed Dec. 14, 2010, which is incorporated herein by reference in its entirety and made a part hereof. 
     
    
     TECHNICAL FIELD 
       [0002]    An example embodiment pertains generally to spectroscopic or radiation analysis and high-pressure and high-temperature research in simulated environmental conditions. More specifically, an example embodiment relates to an apparatus and method for X-ray crystallography of both organic and inorganic liquid suspensions, and environmental systems and structures. 
       BACKGROUND 
       [0003]    In traditional crystallographic X-ray methods, the sample being analyzed either as a single crystal or fine crystalline powder is generally mounted in stationary manner either by, for example, attaching the sample to a fiber, placing the sample in a thin glass tube, or spreading the sample onto a flat surface. These mounts may be placed in closed or partially open chambers that allow changes in temperature, i.e. high-temperature furnaces, or under pressure. In these chambers the sample may be allowed to interact with a gas other than air. Using liquids in these methods is either extremely difficult or impossible, because of the absorption/dispersion properties of virtually all liquids. In addition, many chambers have a relatively long distance through which radiation must pass through these liquid media between entry and exit of the chamber, further increasing absorption of the radiation. 
       SUMMARY 
       [0004]    According to an example embodiment an apparatus for radiation analysis of a liquid suspension in motion comprises a chamber for holding the liquid suspension; a port for admission of the liquid suspension into the chamber; and a pump or agitator to move the liquid suspension in the chamber during analysis. The movement allows radiation analysis of the solid material suspended in the liquid along different crystalline orientations as the liquid suspension moves. The apparatus further comprises a source of radiation adjacent the chamber with the chamber having one or more windows through which radiation from the radiation source may pass during radiation analysis of the liquid suspension, and a detector adjacent to the chamber. 
         [0005]    According to further example embodiments, a chamber for radiation analysis of a liquid suspension in motion comprises an enclosable volume for holding the liquid suspension; a port for admission of the liquid suspension into the chamber; a recess for receiving a pump or agitator to move the liquid suspension in the chamber during analysis; and one or more windows through which radiation may pass during radiation analysis of the liquid suspension. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0006]    Some embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings in which: 
           [0007]      FIG. 1  shows a schematic layout of an environmental chamber, according to an example embodiment. 
           [0008]      FIG. 2  shows a schematic path of an illuminating electromagnetic beam from the source through the windows of an environmental chamber to the detector, according to example embodiments. 
           [0009]      FIG. 3  shows a front perspective view of a main unit of an environmental chamber, according to an example embodiment, with some internal detail shown in ghosted outline. 
           [0010]      FIG. 4  shows a rear perspective view of the main unit shown in  FIG. 3 , again with some internal detail shown in ghosted outline. 
           [0011]      FIG. 5  shows a rear perspective view of a base unit of an environmental chamber, according to an example embodiment, with some internal detail shown in ghosted outline. 
           [0012]      FIG. 6  shows a cross-section of the assembled main and base units of an environmental chamber, according to an example embodiment. 
           [0013]      FIGS. 7 ,  8  and  9  are flow diagrams showing methods of radiation analysis, according to example embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Disclosed in  FIG. 1  is a schematic view of an environmental pressure chamber  100  capable of withstanding pressures to 2000 bars and temperatures from −50° C. to 500° C. in dynamic conditions. Higher pressures in excess of 2000 bar can be achieved with appropriate reinforcement of the chamber. Thicker chamber walls, stronger assembly bolts, or stronger construction materials may for example be employed when a chamber is required to withstand extreme pressure and/or temperature conditions. The chamber is designed to address many of the limitations of traditional crystallographic X-ray methods. The chamber  100  comprises a closed-circuit loop or channel  102  that may contain a solid (shown schematically by pieces  104 ) in suspension in a liquid suspension or dispersion  106  that is to be analyzed. The closed-circuit loop  102  has included within it an agitator or reciprocating pump  108  combined with a PEEK (polyether ether ketone) check valve (not shown) to circulate the liquid suspension  106  to ensure uniformity while maintaining the solid material  104  in suspension. The pump  108  is composed of PEEK-encased iron and is driven using two solenoids (not shown) disposed on the outside of one leg  102 A of the closed-circuit loop  102 . Access to the loop  102  is provided by a pressure-inlet port  110 , and one or more inlet/outlet ports  112  to allow both chemical adjustment and sampling, as needed, of the liquid suspension  106  at pressure. 
         [0015]    The chamber  100  is equipped with two opposed high-pressure windows  114  and  116  disposed in another leg  102 B of chamber  100 . These windows can be seen in sectional view in  FIG. 2 . One of these windows  114  is an entry window that allows the suspension to be illuminated by a collimated X-ray beam  118  or another electromagnetic beam (e.g., Raman). The second window  116  allows exit of diffracted X-rays or another modified electromagnetic beam. 
         [0016]    The environmental chamber  100  is manufactured using materials that have a low solubility in the selected dispersing liquid suspension  106 , such as stainless steel or titanium. A suitable material for the chamber when using highly corrosive alkaline suspensions is PEEK (polyether ether ketone), but the temperature range of this chamber would thus be limited to less than 200° C. 
         [0017]    With reference to  FIG. 2 , the small entry window  114  accommodates and allows the passage of a thin, well-focused beam  120  from an electromagnetic source  118 . The beam  120  ideally is collimated to a diameter of 0.25 mm to 0.5 mm and passes through the suspension  106  illuminating the dispersed solid  104  which allows radiation analysis of the solid material suspended in the liquid along different crystalline orientations as the liquid suspension  106  moves. 
         [0018]    The diameter of the entry window in the present example design is 2 mm. The larger exit window  116  in the present example design has a diameter of 6 mm, which allows a wide range of angles for the refracted or diffracted beams  122 . These beams are analyzed by a detector  124  located outside the environmental chamber  100 . The distance between the windows  114  and  116  is small and may be adjusted from 0.25 mm to 2 mm, depending on the characteristics of the illuminating source  118  and the absorption characteristics of the windows and the liquid suspension  106 . When the environmental chamber  100  is used at high pressures, the windows may be made from vapor-deposited diamond that may range in thickness to 1 mm, depending on pressure. At near-ambient conditions, the chamber may be outfitted with thin polyester film windows, which will perform satisfactorily, and which have low absorption. 
         [0019]    The environmental chamber  100  is pressured with a gas (not shown) that may or may not react with the liquid suspension  106 . The environmental chamber  100  may be heated by using sets of cartridge heaters placed in regularly distributed holes in a main body (discussed further below) of the chamber or by encasing the chamber with tightly fitting double-walled plates (not shown) that are temperature-controlled using a liquid circulator to either heat or cool the chamber. A thermocouple placed in a thermocouple well (shown at  126  in  FIGS. 3 ,  4  and  6 ) near the entry window  114  is used to facilitate both temperature control and temperature measurement. 
         [0020]    An important aspect of the environmental chamber  100  is that it allows the study of particles in motion, with these particles dispersed in a liquid, while the liquid suspension may be at near vacuum conditions to pressures to 2000 bars or more at temperatures ranging from −50° C. to 500° C. As the pressurizing media are usually in the form of various gases at high pressures, the liquid  106  will be in equilibrium with these gases even though they may react chemically with these gases. Both pressures and temperatures can be controlled with precision. 
         [0021]    The chamber  100  and its entry and exits ports  110  and  112 , the windows  114  and  116 , the agitator or pump  108 , the radiation source  118  and the detector  124  may, in an example embodiment, form part of an apparatus for radiation analysis of a liquid suspension in motion. Under analysis conditions, although it is preferred, it is not strictly necessary that the liquid proceed all the way around the loop  102  driven, by example, by a pump  108 . It is merely necessary that the solids in suspension adjacent the windows (i.e. under analysis) be in motion or some degree of agitation. In this case, the motion may be imparted to the solids contained in the liquid suspension by an agitator  108  with the liquid part of the suspension itself remaining essentially static in the loop. The liquid part will nevertheless pass to the solid particles pulses of energy or vibration imparted to the liquid suspension by the agitator. When the solid particles are in motion, either through continuous flow around the loop or during “static agitation” (as it were), they will tend to move, spin and/or roll around while in suspension in the liquid and this continuous movement allows radiation analysis of the solid particles along different crystalline orientations. 
         [0022]    An example embodiment of the environmental chamber  100  is now described with reference to  FIGS. 3 ,  4 ,  5 , and  6 . 
         [0023]      FIG. 3  shows a main unit (or upper part)  300  of the high-pressure environmental chamber  100  and the location of a round entry window  114 . Although the dimensions of the chamber are not necessarily important, it is envisaged that the chamber could be miniaturized (and made portable) or enlarged without losing functionality. Great convenience may be provided to an analyst by providing the chamber in portable form such that it may be carried and set up with the other elements of the analytical apparatus (radiation source, detector and so forth) at remote geographic sites. The main unit of the environmental chamber, or the chamber itself, may thus have a width of approximately 85 mm, a height of approximately 76 mm, and a thickness of approximately 38 mm. 
         [0024]    One portion of the closed-circuit loop or channel  102  is seen to comprise legs or sections, shown generally at  302 A,  302 B and  302 C. The numerals  302 A,  302 B and  302 C are intended to refer generally to the vertical or horizontal legs or sections of the upper loop which together define a generally inverted U-shaped channel or passage of varying diameter for the liquid suspension  106  in the main unit  300 . 
         [0025]    Also disclosed in ghosted outline in  FIG. 3  are a pressure port  304 , an additional inlet/outlet port  306 , assembly bolt holes  308 , and a well (or recess)  310  to house reciprocating pump solenoids or other electromagnetic pump drive (not shown) for a reciprocating pump, such as pump  108  shown in  FIG. 1 . Also disclosed in ghosted outline in  FIG. 3  is a well  126  to accommodate a thermocouple for temperature measurement/temperature control of the chamber. 
         [0026]    A connection well of cylindrical form is shown at  312 A. This well  312 A accommodates with a tight fit a connection cylinder (visible at  602  in  FIG. 6 ) described in more detail below. A similar connection well  312 B is positioned above the solenoid well  310 . 
         [0027]    A well for entry of the illuminating beam is shown at  115 . This well terminates in the entry window  114 , in this case a circular hole that may have a diameter of 1 mm and that may have a depth of 0.25 mm, where it intersects the channel  302 C to allow the illuminating beam to radiate the suspension. The well  115  accommodates an entry assemblage (not shown) that may consists of tube with a central hole having a diameter of 1 mm that terminates in a seat that may abut the entry window  114 , or include an external entry window  114 , for example a 2-mm diamond disk, and a seal that seals the external window against the chamber at the channel  302 C. The tube may be attached tightly onto the chamber, using a screw nut for example, to withhold the pressure forces present in the channel leg  302 C. 
         [0028]      FIG. 4  shows the same main unit  300  shown in  FIG. 3  but viewed from the side of the exit window  116 . The legs of the upper portion of the closed-circuit loop  102  are again shown generally at  302 A,  302 B and  302 C. The ports  304  and  306 , the pump-drive well  310 , the connection wells  312 A and  312 B, the thermocouple well  126 , and the bolt holes  308  as described above are again shown in ghosted outline and numbered accordingly. 
         [0029]    An exit well for the refracted or diffracted beam  122  (see  FIG. 2 ) is shown at  117 . This well  117  is stepped at three different depths and intersects channel  302 C to define the exit window  116 , in this case a rectangular hole, that may have a width of 1 mm, to allow the exit of the refracted of diffracted beam emanating from the suspension. 
         [0030]    The stepped exit well  117  may allow accommodation, in the smallest step, of an external exit window (not shown), for example a 6-mm diamond disk, and a seal, that may seal the window against the chamber. The next step accommodates an intermediate ring (not shown) to confine and support the exit window and seal against the chamber. The last step accommodates a wide ring (not shown) that screws into the chamber body to support the intermediate ring against the pressure present in the channel  302 C. 
         [0031]    The supporting ring and the wide ring screw may have an outwardly directed cone-shaped central hole that is continuous between the intermediate ring and the wide ring and that allows a wide range of angles for the exit of refracted or diffracted beams  122  (see  FIG. 2 ) 
         [0032]      FIG. 5  shows a base unit (or lower part)  500  for the environmental chamber  100  onto which the main unit  300  described above may be bolted. The two units are bolted together using assembly bolts located in bolt holes  502 . The bolt holes  502  of the base unit  500  line up with the bolt holes  308  of main unit  300  such that both units can be drawn together and secured by bolts (not shown) to define an assembled environmental chamber comprised in two parts by the base  500  and main  300  units respectively. In such an assembled configuration, the upper portion of the closed circuit loop  102  (made up by legs  302 A,  302 B and  302 C) are brought into fluid communication with a lower portion of the closed circuit loop  102  in the base unit  500 . The lower portion of the loop  102  is shown generally by legs  502 A,  502 B, and  502 C. The numerals  502 A,  502 B and  502 C are intended to refer generally to the vertical or horizontal legs or sections of the lower loop which together define a generally U-shaped channel or passage of varying diameter for the liquid suspension in the base unit  500 . 
         [0033]    The base unit  500  also comprises connection wells  312 C and  312 D, and a further complementary well  510  to match up with the electromagnetic pump drive well  310 . Inlet/outlet ports for the loop  102  are provided at  514  and  516 . Base unit mounting holes are present on both sides of the base unit but they are for clarity shown only on one side at  512 . These mounting holes are used to mount and align the chamber assembly. 
         [0034]    Reference is now made to  FIG. 6  which shows a cross-section of the assembled main unit  300  and base unit  500 . This view shows the opposed portions of the closed-circuit circulation loop  102  (comprised by legs  302 A,  302 B,  302 C and  502 A,  502 B and  502 C numbered in parenthesis) of the assembled chamber defined, in this example embodiment, by the main unit  300  and the base unit  500 . 
         [0035]    The closed-circuit loop  102  between both units is completed and sealed by connection cylinders, mentioned above. Here, in this example embodiment, the connection cylinders are seen to comprise one small hollow connection cylinder  602  and one larger hollow connection cylinder  604 . The larger connection cylinder  604  accommodates a magnetic piston assembly  606  and check valve (not shown). The hollow cavities of the connection cylinders form part of the closed-circuit loop  102  when assembled in place. 
         [0036]    In most cases, O-rings  608  are used for the seals between the connection cylinders and the connection wells in which they sit. However, when the circulating liquid degrades the O-ring material, such as in CO 2 —H 2 O liquids at elevated pressures and temperatures, PEEK cone seals and PEEK compression seals are excellent replacements. In high-temperature applications, silver compression seals may be used. In order to mount and align the units of the environmental chamber, mounting holes are present, see for example at  512 ,  FIG. 5 . 
         [0037]    In leg  302 C of the closed-circuit loop, the exit window or slot  116  is provided in the main unit  300  to allow passage of refracted or diffracted electromagnetic radiation, X-rays and the like during radiation analysis of the liquid suspension circulating in the loop  102  of the chamber  100 . 
         [0038]    The environmental chamber has widespread and significant applications, particularly in low-temperature and/or high-pressure mineralogical, geochemical, and bio-geochemical studies, in crystallography, and in chemical and environmental engineering. In addition, the invention has numerous applications in processes involving coal gasification and oil/gas production from tar-sands and oil-shales. An example of an important application is a study involving the sequestration of CO 2  in reservoir rocks in the earth&#39;s crust. In such a study, minerals of interest are brought into suspension in a brine and pressurized by CO 2  gas. This environmental chamber as described herein allows the study, in real time, of possible dissolution or alteration reactions of these minerals with CO 2  as well as the possible precipitation of different minerals. This will allow the evaluation whether and how these reactions cause changes in reservoir rocks. This information is important, as these changes may impact on the permeability and/or porosity of the reservoir rocks and cap rocks, as well as the volume of the reservoir rocks or the cap rocks. 
         [0039]      FIGS. 7 ,  8  and  9  illustrate methods of analysis according to example embodiments of the invention. An apparatus or chamber such as any of those illustrated in  FIGS. 1 to 6  may be used to facilitate the example methods. References to “samples” in this specification and the disclosed methods of analysis is intended to refer to replica or made-up samples of the solid materials, liquid suspensions, brines and so forth that exist in subterraneous conditions. It is not strictly necessary that actual samples of such subterraneous materials be used in the disclosed methods of analysis, although such samples could be used. 
         [0040]    In  FIG. 7 , a method  700  of radiation analysis of a liquid suspension may comprise: at block  702 , providing a chamber for holding the liquid suspension; at block  704 , causing the liquid suspension to move in the chamber to allow radiation analysis of the solid material suspended in the liquid along different crystalline orientations as the liquid suspension moves; at block  706 , passing radiation through the moving liquid suspension; and at block  708 , analyzing the radiation leaving the moving liquid suspension. 
         [0041]    The method may further comprise maintaining the liquid suspension under pressure during radiation analysis. The method may yet further comprise maintaining the liquid suspension at pressures in the range 0-2000 bars, or in excess of 2000 bars, during radiation analysis. The method may further comprise maintaining the liquid suspension at a steady temperature during radiation analysis. The method may further comprise maintaining the liquid suspension at a steady temperature in the range of −50° C. to 500° C. during radiation analysis. 
         [0042]    In  FIG. 8 , a block diagram of method  800  is shown for analyzing, by simulation thereof, the conditions of a dynamic subterranean environment in which solids of interest are placed in suspension in a liquid and are pressurized by a gas at an identified environment temperature. The method  800  may comprise: at block  802 , placing one or more samples of the solids of interest in suspension in a liquid; at block  804 , placing a sample of the liquid suspension in an enclosable chamber; at block  806 , adding a sample of the gas into the chamber to simulate the pressure, temperature and/or gas chemistry of the subterranean liquid suspension; at block  808 , pressurizing and heating the chamber to simulate the subterranean pressure and temperature conditions; at block  810 , causing the liquid suspension to move within the chamber to allow radiation analysis of the solid material suspended in the liquid along different crystalline orientations as the liquid suspension moves; at block  812 , passing radiation through the moving liquid suspension; and at block  814 , analyzing the radiation leaving the moving liquid suspension. 
         [0043]    In  FIG. 9 , a block diagram of method  900  is shown for assessing the environmental impact on subterranean rocks containing minerals of interest which are sought to be recovered by being placed in suspension in a brine and pressurized by a gas. The method may comprise: at block  902 , placing one or more samples of the minerals of interest in suspension in a sample of the brine to form a liquid suspension; at block  904 , placing a sample of the liquid suspension in an enclosable chamber; at block  906 , adding a sample of the gas into the chamber to simulate the chemistry of the subterranean liquid suspension; at block  908 , pressurizing the chamber to simulate the subterranean pressure conditions; at block  910 , causing the liquid suspension to move within the chamber to allow radiation analysis of the minerals suspended in the brine along different crystalline orientations as the liquid suspension moves; at block  912 , passing radiation through the moving liquid suspension; and at block  914 , analyzing the radiation leaving the moving liquid suspension. 
         [0044]    Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof, show by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. 
         [0045]    Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. 
         [0046]    The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.