Abstract:
This document provides methods and materials related to treating mammals (e.g., humans) having a sexual dysfunction that is refractory to treatment with a PDE V inhibitor. For example, methods and materials related to the use of an ACE inhibitor and/or an angiotensin II receptor blocker with a PDE V inhibitor to treat mammals having a sexual dysfunction (e.g., erective dysfunction) that is unresponsive to treatment with a PDE V inhibitor are provided.

Description:
FIELD OF THE INVENTION 
       [0001]    The instant invention relates to a reactor useful in upgrading heavy oils admixed with a catalyst composition in a slurry. 
       BACKGROUND OF THE INVENTION 
       [0002]    A liquid recirculating reactor is highly effective for upgrading heavy oils. Heavy hydrocarbons may be admixed with an active catalyst composition in a slurry form. 
         [0003]    Conventional heavy oil upgrading via hydrprocessing uses relatively inefficient large extrudate catalyst pellets to support the reactions. It has long been recognized that there are significant advantages to using a finely divided slurry catalyst for heavy oil upgrading via hydroprocessing. Past attempts to demonstrate slurry heavy oil hydroprocessing on a large scale have relied on upflow reactors employing bubble column technology. However, such reactors suffer from difficulty in maintaining the desired dispersed bubble flow regime necessary for efficient reactor volume utilization. Past problems with bubble column reactors and difficulties in maintaining the desired bubble flow regime has hindered the development of slurry heavy oil upgrading via hydroprocessing. 
         [0004]    There are examples in the prior art of upflow reactors used in heavy oil hydroprocessing. U.S. Pat. No. 6,278,034 discloses a process in which a reactor contains a slurry bed, and feed is added at the bottom of the reactor. In the instant invention a slurry and feed mixture is added at the bottom of the reactor. There is no slurry bed already present in the reactor. 
         [0005]    U.S. Pat. Nos. 6,454,932 and 6,726,832 disclose hydrocracking of heavy hydrocarbons in upflow reactors containing ebullating catalyst beds in series. The instant invention as noted above, employs a slurry and feed added at the bottom of the reactor. 
         [0006]    U.S. Pat. No. 4,684,456 discloses an upflow reactor employing an expanded catalyst bed. The expansion of the bed is automatically controlled by automatically changing the rate of speed of a recycle pump for the reactor. There is no teaching in this patent of the use of such a reactor with a slurry. 
         [0007]    U.S. Pat. No. 6,660,157 discloses a process for slurry hydrocracking employing a series of upflow reactors with interstage separation. The reactors are not liquid recirculating reactors, such as those employed in the instant invention. 
       SUMMARY OF THE INVENTION 
       [0008]    The instant invention relates to a reactor useful in upgrading heavy oils admixed with a catalyst composition in a slurry. The liquid recirculating reactor of this invention employs a dispersed bubble flow regime, which requires a high liquid to gas ratio. A dispersed bubble flow regime results in more even flow patterns, increasing the amount of liquid that can be upgraded in a single reactor. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0009]      FIG. 1  is a schematic of a liquid recirculating reactor. 
           [0010]      FIG. 2  is a graph depicting the beneficial effect of higher liquid to gas ratio on maintaining dispersed bubble flow. Lower gas to liquid ratios result in slug flow or gas continuous flow. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    The instant invention is a liquid recirculating reactor suitable for hydroconversion employing slurry feeds comprising heavy oil hydrocarbons and catalysts. 
         [0012]    Preparation of active slurry catalysts suitable for use in the instant invention are disclosed in the following co-pending applications: U.S. Ser. Nos. 10/938,202, 10/938,269, 10/938,200, 10/938,438, and 10/938,003. These applications are incorporated by reference. The slurry composition is prepared by a series of steps, involving mixing a Group VIB metal oxide, such as molybdenum and aqueous ammonia to form an aqueous mixture, and sufiding the mixture to form a slurry. The slurry is then promoted with a Group VIII metal. The slurry is then mixed with a heavy hydrocarbon oil and combined with hydrogen gas to produce the active slurry catalyst. The catalyst is kept mixed in storage until combined with feed in a hydroconversion process. 
         [0013]    The co-pending applications mentioned above are also suitable for further information on the hydroconversion processes that may be used in this reactor. Hydroconversion processes include thermal hydrocracking, hydrotreating, hydrodesulfurization, hydrodenitrification and hydrodemetalization 
         [0014]    The feeds suitable for use in hydroconversion processes of this reactor are selected from the group consisting of atmospheric residuum, vacuum residuum, tar from a solvent deasphalting unit, atmospheric gas oils, vacuum gas oils, deasphalted oils, olefins, oils derived from tar sands or bitumen, oils derived from coal, heavy crude oils, synthetic oils from Fischer-Tropsch processes, and oils derived from recycled wastes and polymers. 
         [0015]    The liquid recirculating reactor of this invention is an upflow reactor in which heavy hydrocarbon oil is admixed with a slurry comprising a catalyst and a hydrogen rich gas at elevated pressure and temperature and hydroprocessed (preferably hydrocracked) for the removal of heteratom contaminants, such as sulfur and nitrogen. 
         [0016]    Suitable pressures include a range from 1500 to 3500 psia., preferably from 2000 to 3000 psia. Suitable temperatures include a range from 700 to 900 F, preferably from 775 to 850 F. 
         [0017]    The reactor generally includes a pump that recirculates liquid from near the top (outlet) of the reactor back to the bottom (inlet), at typically 5-10 times the rate of the incoming heavy oil stream. In slurry catalyst use, the particles are so small (such as 1-10 micron) that liquid recirculation with a pump is not usually necessary to create sufficient motion of the catalyst to obtain a perfectly mixed flow effect. Pumps are used more frequently with extrudate catalyst pellets (typically 1 mm in diameter by 2 mm in length). Material does flow through the pump in the recirculation process, even in slurry catalyst use. The conventional approach to slurry heavy oil hydroprocessing, has been to rely only on the incoming liquid and gas flow to get the desired catalyst motion (called a slurry bubble column). However, a slurry bubble column is limited in its ability to tolerate the large volumes of hydrogen rich gas required for the upgrading. Slurry bubble columns tend to suffer due to bubble coalescence (the formation of large gas bubbles from smaller bubbles). Bubble coalescence creates highly uneven flow patterns in the reactor that significantly reduce performance. The amount of liquid that can be upgraded in a single reactor is limited. The uneconomic use of multiple reactors in parallel is required. In contrast, the liquid recirculating reactor is able to handle higher gas rates (and therefore higher fresh liquid feed rates) than conventional slurry bubble columns, while maintaining dispersed bubble flow. This is due to the beneficial effect that oil to gas ratio (fresh feed plus recirculated liquid) has on flow regime. The importance of this effect has not previously been appreciated. 
         [0018]    In  FIG. 1 , a schematic of the preferred embodiment of liquid recirculating reactor is depicted. The reactor  12  comprises a cylinder, having a consistent diameter. The lower end of the reactor  12  is closed off with an end piece  17  while the upper end of the reactor  12  is closed off with a roof  18 . 
         [0019]    A feed line,  24 , which is joined by hydrogen feed line  22 , leads into the lower end of the reactor  12 , below the inlet distributor tray. The feed comprises a mixture of heavy hydrocarbons and a catalyst slurry, along with hydrogen. The reaction occurs as the hydrocarbon and catalyst slurry mix moves upward from the distributor tray. An overhead product withdrawal line  28  leads from the roof  18 . Vapor comprising product and hydrogen, admixed with some slurry is passed overhead to separators, while liquid and slurry is recirculated. Gases are also passed overhead. The liquid product is separated form the catalyst particles either by means of internal separation or by way of external separation. Neither method is shown in this diagram. 
         [0020]    A mixing device in the form of a downcomer  34  is located inside the reactor  12 . Material not passed overhead is recirculated through the downcomer  34 . The downcomer  34  acts to keep the catalyst concentration profile and the temperature profile along the length of the reactor  12  as even as possible, maintaining the bubble flow regime. The downcomer  34  comprises at its upward end a cone  38 . The cone  38  contains upcomers which permit gases and liquid to flow upwardly through the cone. The downcomer  34  has an open upper end  42 , but the lower end terminates in the inlet of the recirculation pump  21 . The outlet of the recirculation pump  21  (not shown) discharges material near the inlet distributor tray  20 . 
         [0021]    Hydrogen is continuously combined with feed line  24  through the flow line  22 . Sufficient hydrogen is introduced so that the superficial gas velocity through the slurry bed  30  is from 2 through 6 cm/s. The slurry bed is typically maintained at a temperature in the range of about 700 through 900 F. Unreacted hydrogen is withdrawn continuously along the flow line  28 . This hydrogen can be recycled (not shown). 
         [0022]    The cone  38  of the downcomer  34  permits the bulk of the gas bubbles to escape from fluidized slurry that enters the upper end  42  of the downcomer  34 . The downcomer  34  transports the degassed slurry to a lower point in the reactor  12 . 
         [0023]      FIG. 2  illustrates the flow regimes in a three-phase fluidized bed. Bubble flow, (particulate fluidization), slug flow (transition zone) and gas continuous flow (aggregative fluidization) are the three phases depicted. Bubble flow, the target flow regime tends to occur in situations where there is high liquid to gas ratio.  FIG. 2  illustrates bubble flow occurring in the range of velocity ratios, u L /u G  exceeding 1.5 when the average superficial gas velocity is in the range from 2-6 cm/sec.