Abstract:
An advanced methane and ammonia recovery system processes gaseous waste from domestic livestock and poultry farms to reduce the green house gasses which are presently dumped into the environment and to produce useful material. The system includes a gas recovery system. The methane and ammonia recovery system captures ammonia and methane and converts the ammonia into fertilizer and methane into energy. The system is designed to substantially reduce the amount of green house gases introduced into the environment, while providing additional income to the domestic livestock and poultry farms

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to processing treatment of waste from domestic livestock and poultry operations and in particular to an integrated system for efficiently processing waste material from domestic livestock and poultry operations. 
         [0002]    Domestic livestock and poultry operations in the United States produce a substantial portion of the food regularly consumed by the pubic. Unfortunately, these operations also produce significant waste which must be dealt with, and significant odors not appreciated by local residents. Until the present time, no large scale systems have been developed to deal efficiently with green house gas created in the form of methane. 
       BRIEF SUMMARY OF THE INVENTION 
       [0003]    The present invention addresses the above and other needs by providing an advanced methane and ammonia recovery system which processes gaseous waste from domestic livestock and poultry farms to reduce the green house gasses which are presently dumped into the environment and to produce useful material. The system includes a gas recovery system. The methane and ammonia recovery system captures ammonia and methane and converts the ammonia into fertilizer and methane into energy. The system is designed to substantially reduce the amount of green house gases introduced into the environment, while providing additional income to the domestic livestock and poultry farms. 
         [0004]    In accordance with one aspect of the invention, there is provided a gas recovery system including a barn, a gas capture vessel, an ammonia/methane separator, a compressor/chiller and membrane unit, and a methane storage tank. The gas capture vessel has a height between approximately 20 feet and approximately 25 feet and a diameter between approximately eight feet and approximately ten feet, and resides at a peak of the barn for collecting gaseous waste. A first methane sensor resides inside the gas capture vessel between approximately two feet and approximately four feet below a top of the gas capture vessel and a second methane sensor resides inside the gas capture vessel vertically between approximately 2.5 feet and approximately four feet above a bottom of the gas capture vessel. A first ducting fluidly connects the gas capture vessel to the ammonia/methane separator and a second ducting fluidly connects the ammonia/methane separator and the compressor/chiller and membrane unit. A fan resides in the flow between the ammonia/methane separator and the compressor/chiller and membrane unit and controlled by the first methane sensor and the second methane sensor. A third ducting fluidly connects the compressor/chiller and membrane unit to the methane storage tank for carrying methane from the compressor/chiller membrane unit to the methane storage tank. The compressor/chiller and membrane unit separates methane gas from other gasses and the methane gas stored in the methane storage tank may be used to power a generator. 
         [0005]    In accordance with another aspect of the invention, there is provided a method for controlling a gas recovery system. The method includes the steps of initially turning to OFF a fan used to draw gaseous waste from a gas capture vessel through the gas recovery system. The system then enters a loop and tests if the fan is ON or OFF. If the fan is ON and if a first gas sensor residing inside the gas capture vessel proximal to a top of the gas capture vessel is sensing the presence of the gaseous waste, the fan remains ON. If the fan is ON and if the first gas sensor is not detecting the presence of the gaseous waste, the fan is turned OFF. If the fan is OFF, leaving the fan OFF if either or both the first gas sensor is not sensing the presence of the gaseous waste and a second gas sensor residing inside the gas capture vessel proximal to a bottom of the gas capture vessel is not sensing the presence of the gaseous waste. If the fan is OFF, turning the fan ON if both gas sensors are detecting the presence of the gaseous waste. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0006]    The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
           [0007]      FIG. 1  is a block diagram of a methane and ammonia recovery system according to the present invention. 
           [0008]      FIG. 2  depicts a barn with a gas capture vessel residing at a peak, and gas processing equipment. 
           [0009]      FIG. 3  shows a perspective view of the gas capture vessel. 
           [0010]      FIG. 4  shows a side view of the gas capture vessel. 
           [0011]      FIG. 5  is a cross-sectional view of the gas capture vessel taken along line  5 - 5  of  FIG. 4 . 
           [0012]      FIG. 6  is a method according to the present invention. 
           [0013]      FIG. 7  depicts a small barn with the gas capture vessel residing at a peak, and gas processing equipment. 
       
    
    
       [0014]    Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
         [0016]    An advanced methane and ammonia recovery system according to the present invention is shown in  FIG. 1 . A livestock or poultry barn, house, and/or enclosure  10  produces gaseous waste  13 . The gaseous waste  13  is collected by a gas capture vessel  14  residing at a peak  10   a  of the barn  10 . The gaseous waste  13  is lighter than air and rises into the gas capture vessel  14 . The gaseous waste  13  is collected in the gas capture vessel  14  and carried by first ducting  16  to an ammonia/methane separator  18  (for example, an ammonia scrubber). The ammonia/methane separator  18  separates ammonia from other gasses (primarily methane) in the gaseous waste  13 . The ammonia, which is converted into ammonium sulfate, is carried by ammonia ducting  28  to an ammonium sulfate storage tank  29  for further drying into fertilizer. 
         [0017]    The other gasses are carried by second ducting  20  to a compressor/chiller and membrane unit  22  where the methane is separated from oxygen and nitrogen. The separation is preferably done by selectively permeable membrane(s). The compressor/chiller and membrane unit  22  preferably includes a fan to draw the gaseous waste  13  from the gas capture vessel  14  to the ammonia/methane separator  18  and from the ammonia/methane separator  18  to the compressor/chiller and membrane unit  22 . Methane captured by the compressor/chiller and membrane unit  22  is carried by a third ducting  23  to a methane storage tank  24 . 
         [0018]    A perspective view of the gas capture vessel  14  is shown in  FIG. 3 , a side view of the gas capture vessel  14  is shown in  FIG. 4 , and a cross-sectional view of the gas capture vessel  14  taken along line  5 - 5  of  FIG. 4  is shown in  FIG. 5 . The gas capture vessel  14  comprises a vertical cylindrical body  14   a  and a frustoconical shaped top  14   b  tapering to a peak where the duct  16  receives the gaseous waste  13  collected in the gas capture vessel  14 . 
         [0019]    The cylindrical body  14   a  has a height H 1  which is preferably between approximately 20 feet and approximately 25 feet tall and a diameter D 1  which is preferably between approximately eight feet and approximately ten feet, but may vary outside this range depending on the number of animals in the barn. Gas sensors S 1  and S 2  reside inside the cylindrical body  14   a . An upper gas sensor S 1  resides a second height H 2  below the top of the cylindrical body  14   a  and a lower gas sensor S 2  resides a third height H 3  above the base of the cylindrical body  14   a . The gas sensors are preferably methane sensors, but may sense any gas present in the gaseous waste  13  in sufficient quantities to allow reliable sensing of the presence of the gaseous waste  13  in the gas capture vessel  14 . The height H 2  is preferably between approximately two feet and approximately four feet depending on the number of animals in the barn. The height H 3  is preferably between approximately 2.5 and approximately four feet, and is more preferably approximately four feet. 
         [0020]    A method for controlling an operation of the gas recovery system is described in  FIG. 6 . The fan is initially turned to OFF at step  100  and a control loop is entered. If the fan is ON at step  102 , and if the first gas senor S 1  is detecting (i.e., S 1 =1) the presence of the gaseous waste  13 , the fan remains ON. If the fan is ON at step  102 , and if the first gas senor S 1  is not detecting (i.e., S 1 =0) the presence of the gaseous waste  13 , the fan is turned OFF at step  105 . If the fan is OFF at step  102 , and if both the first senor S 1  is detecting (i.e., S 1 =1) the presence of the gaseous waste  13  and the second senor S 2  is detecting (i.e., S 2 =1) the presence of the gaseous waste  13  at step  106 , the fan is turned ON at step  108 . If the fan is OFF at step  102 , and if either or both the first senor S 1  is not detecting (i.e., S 1 =0) the presence of the gaseous waste  13 , and the second senor S 2  is not detecting (i.e., S 2 =0) the presence of the gaseous waste  13  at step  106 , the fan remains OFF. In all cases, the control loop returns to step  102 . 
         [0021]    A small barn  30  with the gas capture vessel  14  residing at a peak, and gas processing equipment is shown in  FIG. 7 . The gas produced in the small barn  30  may not be sufficient to make the system shown in  FIGS. 1 and 2  economically feasible. As a result, a small system comprising a fan/compressor unit  32  connected to the gas capture vessel  14  by the ducting  16 , and a gas storage tank  34  connected to the fan/compressor unit  32  by ducting  33 , is an alternative system. The gas stored in the tank  34  is periodically collected for processing at a remote location which services small farms in the local area. 
         [0022]    While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.