Abstract:
A self-contained, portable, waste water evaporating apparatus is shown. A solar-operated submersible pump pumps waste water from just under the surface of a waste water pit, through a pair of automatic backflushing filters and out misters located around the bank of the waste water pit. At a predetermined pressure across the automatic backflushing filters, the automatic backflushing filters are reverse cycled, one at a time, to backflushing particles back into the waste water pit. Periodically, the misters are purged and/or cleaned to remove particles therefrom. In response to sunlight, solar panels provide DC voltage directly to the submersible pump. If pressure from the submersible pump gets excessive, a pressure relief valve removes the excess pressure.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to evaporation of waste fluids and, more particularly, to the evaporation of waste fluids at remote locations involving fracing of oil and/or gas wells. 
         [0003]    2. Description of the Prior Art 
         [0004]    Throughout the United States, the most common way of getting rid of liquid waste is to inject the liquid waste into a disposal well. Waste water disposal wells are becoming quite common, especially in regions where there is drilling for oil and gas. If hydraulic fracing is used, millions of gallons of water or other fluids will be used in the fracing process to break up the rock and retrieve the oil and gas. The fluid used in the fracing process will come back up along with additional ground water. 
         [0005]    Most of this waste water is trucked to disposal wells and injected thousands of feet underground for permanent storage. The hauling of the waste water to disposal wells is expensive. Also, the waste water being injected underground has a tendency to leak. 
         [0006]    In the State of Texas alone, the amount of waste water due to fracing that is being disposed of in disposal wells increased from 46 million barrels in 2005 to 3.5 billion barrels in 2011. On average, companies in Texas dispose of 290 million barrels of waste water each month. In the State of Texas alone, there are more than 8,000 active disposal wells, about 850 of which are large commercial operations. 
         [0007]    One of the alternatives to disposing waste fluids in a disposal well is to evaporate the fluids to the extent possible so that less fluids will have to be put in a waste disposal well. At many drilling sites, surface collection ponds, or lined pits, may be used to collect the waste water. Some of the surface collection ponds use an evaporation process to reduce the amount of water in the waste water fluid. Systems that spray water into the atmosphere have been used in the past, but are generally very inefficient. Water cannons have been used to spray water into the atmosphere over waste water ponds or containment areas. 
       SUMMARY OF THE INVENTION 
       [0008]    It is an object of the present invention to provide a method and apparatus for evaporation of waste fluids. 
         [0009]    It is another object of the present invention to provide a self-contained apparatus to evaporate waste fluids generated in the fracing of oil and gas wells. 
         [0010]    It is yet another object of the present invention to provide a self-contained system that may be moved from one location to another and quickly set into operation to evaporate waste water. 
         [0011]    It is still another object of the present invention to provide a portable system to evaporate waste water wherever the waste water is collected. 
         [0012]    Solar panels provide power to a pump controller to operate a submersible pump contained in a waste water pit. The submersible pump pumps the waste water through automatic backflushing filters to remove the particles therefrom. After the removal of the removal of the particles, the pressurized waste water flows through a plurality of misters to evaporate the waste water into the atmosphere. 
         [0013]    A filter controller is operated by a pressure gauge across the automatic backflush filters. When a predetermined pressure is reached, the pressure triggers the filter controller. The filter controller, which receives its power from any suitable source including solar panels or batteries, will operate the valves on the inlet side of the automatic backflush filters. By operating the valves in a certain order, backflushing can be obtained in each of the automatic backflush filters. 
         [0014]    In case the pressure from the submersible pump gets too great, a pressure relief valve is included which discharges any fluid back into a waste water pit. Also, if the evaporator unit cannot handle all of the flow, any excess waste water is dumped back into the waste water pit. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a schematic flow diagram of the present invention. 
           [0016]      FIG. 2  is a pictorial flow diagram of the present invention. 
           [0017]      FIG. 3A  shows the normal operation of a pair of automatic backflushing filters. 
           [0018]      FIG. 3B  is the same as  FIG. 3A , except one of the filters is being backflushed. 
           [0019]      FIG. 3C  is the same as  FIG. 3B , except the other filter is being backflushed. 
           [0020]      FIG. 4  is a pictorial view of the connections to the automatic backflushing filters. 
           [0021]      FIG. 5  is a perspective view of one of the misters. 
           [0022]      FIG. 6  is a pictorial view of the present invention being used to evaporate waste water from a waste water pit. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Referring first to  FIG. 6  of the drawings, a waste water pit  11  is shown filled with waste water  13 . Floating on the waste water  13  is a floatation device  15  that has suspended there below a submersible pump  17 . The submersible pump  17  pumps the waste water  13  through pump line  19  to the portable waste water evaporating apparatus  21 . From the portable waste water evaporating apparatus  21 , after filtration the waste water  13  is pumped through evaporation line  23  to the misters  25  located on the bank  27  of the waste water pit  11 . If the pressure inside of automatic backflushing filters  29  exceeds a predetermined amount, the automatic backflushing filters  29  will be backflushed through filter backflush line  31  into waste water pit  11 . 
         [0024]    Referring now to  FIGS. 1 and 2  in combination, operation of the portable waste water evaporating apparatus  21  will be explained in more detail. The submersible pump  17  in the preferred embodiment is designed to flow approximately 15 gallons per minute (gpm) at approximately 65 pounds per square inch (psi). Solar panels  33  produce an output voltage of between 30 and 300 volts, depending upon the amount of sunlight that is available. Power from the solar panels  33  goes through a circuit breaker  35  to a pump controller  37 . From the pump controller  37 , the power generated by the solar panels  33  feeds directly to the submersible pump  17 , which is a DC pump. The circuit breaker  35  ensures that the voltage generated by solar panels  33  does not exceed the maximum voltage level of the submersible pump  17 . This is important on a really hot day with a lot of sunshine. As the sunlight decreases, the amount of voltage generated by the solar panel  33  decreases and, hence, the speed of the submersible pump  17  decreases. 
         [0025]    When power is being provided by the solar panels  33  via circuit breaker  35  and pump controller  37  to the submersible pump  17 , waste water  13  is pumped from the waste water pit  11  through pump line  19  and valves  39  and  41  to automatic backflushing filters  29 A and  29 B. After filtration in the automatic backflushing filters  29 A and  29 B, the waste water flows through flow meter  43  that records the amount of flow. Gate valve  45  prevents backflow from the evaporation line  23  and the misters  25 . While the flow meter  43  will record the flow of the waste water  13 , gate valve  45  will prevent back-flow of the waste water  13 . 
         [0026]    The submersible pump  17  as located in the waste water pit  11  has the inlet side of the pump slightly lower than the outlet side of the pump. This ensures waste water  13  flows across the submersible pump  17  in the proper manner to help keep the submersible pump  17  cool. The location of the submersible pump  17  is just below the surface of the waste water  13  contained in the waste water pit  11  because there are less contaminates towards the surface than there will be towards the bottom of the waste water pit  11 . 
         [0027]    Monitoring the pressure across the automatic backflushing filters  29 A and  29 B is a pressure gauge  47 . The pressure as measured across automatic backflushing filters  29 A and  29 B by the pressure gauge  47  is automatically fed to filter controller  49 . Because the filter controller  49  requires much less power than the submersible pump  17 , a separate solar panel  51  and battery  53  is used to operate the filter controller  49 . In this manner, the solar panel  51 , battery  53  and the filter controller  49  can be a separate stand-alone unit which is simpler and easier to operate. 
         [0028]    When the pressure measured by pressure gauge  47 , which measurement is being taken across automatic backflush filters  29 A and  29 B, exceeds a predetermined amount the filter controller  49  will operate valves  39  and  41  in such a manner to backflush one at a time the automatic backflushing filters  29 A and  29 B. The waste water  13  from the backflushing of automatic backflushing filters  29 A and  29 B is fed through filter backflush line  31  into waste water pit  11 . 
         [0029]    Referring now to  FIGS. 3A through 3C , the backflushing of automatic backflushing filters  29 A and  29 B will be explained in more detail. Normal operation of the automatic backflushing filters  29 A and  29 B is shown in  FIG. 3A  with the waste water  13  coming in through pump line  19  into both automatic backflushing filters  29 . After filtration, the waste water  13  flows out through outlet  55 . 
         [0030]    If the pressure gauge  47  exceeds a predetermined amount, the filter controller  49  will switch valve  39  from the position shown in  FIG. 3A  to the position as shown in  FIG. 3B . 
         [0031]    Referring now to  FIG. 3B , as the waste water flows in through pump line  19  is filtered and out filter outlet  55 , the waste water  13  may either flow left or right. To the right, a back pressure is built up in the evaporator line  23  by the misters  25  (see  FIG. 6 ). To the left of filter outlet  55 , the back pressure is less. Therefore, the waste water will flow up through automatic backflushing filter  29 A, past valve  39 , and out filter backflush line  31  to the waste water pit  11 . 
         [0032]    After a predetermined amount of time, valves  39  and  41  switch to the positions as shown in  FIG. 3C . In  FIG. 3C , waste water comes in through pump line  19  and flows through automatic backflushing filter  29 A and out filter outlet  57 . However, when the waste water reaches filter outlet  55  of automatic backflushing filter  29 B, the pressure in filter outlet  55  is less than the pressure in the evaporator line  23  that connects to the misters  25 . Therefore, the waste water from automatic backflushing filter  29 A will flow up through automatic backflushing filter  29 B through valve  41  and out filter backflush line  31 , which is illustrated in  FIG. 3C . After a second predetermined amount of time as set by the filter controller  49 , valves  39  and  41  will be switched back to the positions as illustrated in  FIG. 3A , backflushing terminated and normal filtration again being provided by the automatic backflushing filters  29 A and  29 B prior to flowing the waste water  13  out through evaporator line  23  to misters  25 . During the backflushing operation, the location of the filter backflush line  31  inside of waste water pit  11  should be some distance away from the submersible pump  17  as contained in the waste water pit  11  (see  FIG. 6 ). 
         [0033]    While the system is designed to operate at a maximum of 65 psi at 15 gpm, something could happen to restrict the flow. If that occurs, pressure could built up that would exceed 65 psi. As a safety feature, a pressure release valve  59  is provided on the pump line  19  and that connects through a pressure release line  61  back into the waste water pit  11  (see  FIGS. 1 and 2 ). While the pressure release valve  59  and the pressure relief line  61  are optional, they are a safety feature that should be included. By appropriate check valves, the pressure release valve  59  could be connected to the filter backflush line  31  for discharge back into the waste water pit  11 . 
         [0034]    Over time, contaminants have a tendency to build up in the misters  25 . A battery-operated automatic flush valve  63  may be opened so that waste water  13  flows through evaporator line  23  past misters  25  and out flush line  65  back into waste water pit  11  (see  FIGS. 1 and 2 ). This allows the contaminants to be flushed out of the evaporator line  23  and hopefully out of the misters  25 . 
         [0035]    Referring now to  FIG. 4 , a portion of the portable waste water evaporating apparatus  21  is shown. The automatic backflushing filters  29 A and  29 B are located on a frame  67  that has a top  69  and a base  71 . The automatic backflushing filters  29 A and  29 B are located on legs  73 , extending down to the base  71 . Mounted on the top  69  is a solar panel  51 . Immediately there below is the battery  53  and filter controller  49 . This can be purchased as a single unit. 
         [0036]    Above each of the automatic backflushing filters  29 A and  29 B inside of valve housing  75  and  79  are located valves  39  and  41 , respectively. During normal operation, the waste water  13  will flow in from submersible pump  17 , through pump line  19 , into valves  39  and  41 , and to automatic backflush filters  29 A and  29 B, respectively. During backflushing, the backflush fluid will go out through filter backflush line  31  to the waste water pit  11 . 
         [0037]    Referring now to  FIG. 5 , an individual mister  25  is shown. The mister  25  can be mounted on a rod  81  the lower end of which is stuck into the ground on the bank  27  of the waste water pit  11 . The top end of the rod  81  extends up into rod receiving cavity  83  of the mister  25 . The rod  81  is approximately 5 ft. long so that the mister  25  is a distance above the bank  27 . The rod receiving cavity  83  is in a fitting  85  of the mister  25 . The fitting  85  has the rod receiving cavity  83  therein and a small line  87  that connects down to the evaporation line  23  (see  FIG. 2 ). Above the fitting  85  is located a check valve  89  so that flow from the small line  87  can only be in one direction, i.e., towards the top. Mounted at the top of mister  25  is a four-way distributor manifold  91  that receives filtered waste water through small line  87 . From the four-way distributor manifold  94 , pressurized waste water is distributed to each evaporation head  93 A,  93 B,  93 C and  93 D. 
         [0038]    Each of the misters  25  (including all four evaporator heads  93 ) has a flow rate of roughly 8 gals./hour. At a flow rate of 15 gpm from the submersible pump  17 , that flow rate will support  112  misters  25 . 
         [0039]    The automatic backflushing filters  29 A and  29 B filter out particles down to approximately 70μ, which is about as small as the naked eye can see. However, periodically, particles may get stuck in the evaporator heads  93 A,  93 B,  93 C or  93 D. On each of the evaporator heads  93 A,  93 B,  93 C and  93 D are located tabs  95  that allow the respective evaporator head  93  to be removed and cleaned. 
         [0040]    In a typical set up by the present invention, the flow rate would be approximately 15 gpm. Assuming there are twelve hours of operating time, that is 10,800 gallons of waste water that can be evaporated per day, which is approximately 257 barrels. If the cost of hauling and ejection of waste water is $10 per barrel, that&#39;s a savings of $2,570 per day. 
         [0041]    At the end of the drilling operation, the misters  25  can be removed and an irrigation system connected thereto to revegetate the drilling site.