Patent Publication Number: US-2010111776-A1

Title: Liquid level sensor for a distillation tube used with a micro-refinery

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation in part of U.S. patent application Ser. No. 12/488,558 which is a continuation in part of U.S. patent application Ser. Nos. 12/110,242 and 12/110,158. U.S. patent application Ser. Nos.: 12/488,558, 12/110,242 and 12/110,158 are hereby incorporated by reference. 
    
    
     BACKGROUND 
     Refineries are used to produce hydrocarbons such as gasoline and ethanol. Some refineries use a distillation tube the separate ethanol from other liquids. A problem with the distillation is monitoring the amount of liquid that has accumulated at the bottom of the distillation tube. What is needed is an improved sensor for detecting the fluid level at the bottom of a distillation tube. 
     SUMMARY OF THE INVENTION 
     The present invention is directed towards a micro-refinery system that includes a fermentation tank, a heater and a distillation tube. Feedstock is placed in the fermentation tank and fermented with yeast. After fermentation, the ethanol is separated from the water and other liquids by processing the fluids through a distillation system. In an embodiment, the distillation system of the present invention includes a pump, a heater, a distillation tube and a gimbaled mechanism that is used to position the distillation tube in a vertical orientation. The pump pumps the liquids from the fermentation tank through the heater to cause the water and ethanol to boil and vaporize. The vaporized liquid is directed to the bottom of the distillation tube. As the vapors travel higher through the distillation tube, the ethanol molecules separate from the water molecules and exit the upper part of the distillation tube column. If water and other non-ethanol liquids vaporize, these vapors will tend to be condensed on the sides of the distillation tube as they cool in the distillation tube. The condensed liquids may then adhere or drip down the inner walls of the distillation tube rather than exiting the top of the tube. 
     The distillation system can also include a closed loop internal electromechanical float circuit at the base of the distillation tube that can measure the level of fluid so the heating source can be adjusted. If excessive fluid accumulates at the bottom of the column, the heat can be increased to accelerate the vaporization. Conversely, if there is very little fluid at the bottom of the column, the heat can be reduced to slow the vaporization rate. Ideally, the fluid is heated to a constant temperature for optimum vaporization to occur. If the temperature is not maintained properly, the column vapor, pressure and quality of existing fuel can become unstable. 
     In an embodiment, magnetic sensors can be place in a sensor tube that is inserted inside the distillation tube column base with a doughnut or other shaped floats containing a magnetic. As the fluids at the base of the distillation tube column rise and lower, the magnetic float travels up and down in the magnetic sensor tube. The position of the magnetic float is detected to provide liquid level feedback to an external control system outside the column. 
     Problems can occur with this method when fluids become sticky or contain disruptive material that can obstruct the floats mechanical movement resulting in improper liquid level detection. This type of error can cause the external distillation control system to become unstable or stop functioning all together. 
     In order to solve this problem the sensor tube can be replaced by a guide wire and a new float containing a north magnetic field projecting towards the outer walls of the column. An external magnetometer circuit can be mounted externally outside the base column to sense the internal north magnetic signal as it travels up and down the guide wire. In an embodiment, the guide wire is made of a slippery material such as Teflon or stainless steel that is coated with a lubricious material. Because the material is very smooth and self lubricating, the fluid particles will not be able to adhere to the surface. If any particles do stick to the guide wire, the weight or buoyance of the float will tend to knock these pieces of material off of the guide wire. The internal surface of the float can also be a very smooth surface that from a self lubricating material. 
     A first advantage of the guide wire contains substantially less mass and friction than the tube which prevents the obstruction of the float movement due to problematic fluids. Second, the external magnetometer provides better measurement resolution and cannot be damaged by the harsh internal base column environment. The internal column base magnetic sensors and housing tube are also removed from the distillation tube creating more room for distillation which allows the system to operate more efficiently. In this embodiment, the column base must also be made from non metallic and/or non magnetic materials to allow the magnetic signals to penetrate the external parameter of the column. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an embodiment of the micro refinery 
         FIG. 2  is a side view of an embodiment of a distillation tube liquid level sensor; 
         FIG. 3  is a side view of an embodiment of a distillation tube liquid level sensor; 
         FIG. 4  is a side view of an embodiment of a distillation tube liquid level sensor; 
         FIG. 5  is a top view of an embodiment of a distillation tube liquid level sensor; 
         FIG. 6  is a top view of an embodiment of a distillation tube liquid level sensor; and 
         FIG. 7  is a top view of an embodiment of a distillation tube liquid level sensor. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is directed towards a micro-refinery system that can produce ethanol. The components of the micro refinery  101  will be described with reference to  FIG. 1 . In an embodiment the fermentation tank  103  rests on one or more load cells  105  that detect the downward force and produce corresponding electrical output signals. The load cells  105  are coupled to a system controller  151  that monitors the weight of the tank  103  and all contents within the tank  103  throughout the ethanol conversion process. The load cell  105  output signals are proportional to the detected weight. In an embodiment, the system controller  151  can go through a calibration process which detects the weight of the empty tank  103  and stores the empty tank weight as an offset value. The offset value can then be subtracted from any detected weight so that the system controller  151  can detect the weight and quantity of materials that are inserted into the tank  103 . The fermentation tank  103  calibration process may be repeated each time a batch of materials is processed. 
     The system controller  151  may provide a display and/or audio instructions which may indicate the sequence of materials and quantities to be inserted based upon the estimated quantity of ethanol to be produced. For example in an embodiment, a user may input the quantity of ethanol desired. The system then calculates the expected quantities of materials required to produce the desired quantity of ethanol and instructs the user to insert specific quantities of sugar and feedstock. To start the fermentation process, the lid  111  is opened and a specific ratio of sugar and feedstock are inserted into the tank  103 . 
     In an embodiment, the sugar is the first material added to the fermentation tank  103 . The weight of the sugar is detected by the system controller  151  and the corresponding volume of water is determined. After the sugar has been added, the system controller  151  can instruct the user to insert the feedstock. The system controller  151  can detect the weight of feedstock and provide instructions and information regarding the quantity of feedstock to add to the fermentation tank. The system controller  151  can detect the weight of the materials being inserted and may provide instructions to the user such as: add more, slow the rate of insertion in preparation to stop and stop. The system controller  151  may have a visual display that indicates the volume of materials added to the tank so the user knows when to stop adding materials to produce the desired volume of ethanol. The system controller  151  may also provide feedback if errors are made. For example, if the system controller  151  detects that too much sugar was added, the system may compensate for this error by increasing the quantity of feedstock to be added to the fermentation tank  103  for the extra sugar. 
     In another embodiment, the sugar, yeast and other feedstock components such as: phosphorus, sulfur, potassium, magnesium, minerals, amino acids and vitamins can be stored in containers  191  that are coupled to the fermentation tank  103  and the control system  151  can control valves  193  coupled to the containers. Thus, the control system  151  can add the required materials into the fermentation tank  103  so that the insertion of the sugar, yeast and other components is automated. The system may also allow for the large initial quantity of materials to be manually inserted into the fermentation tank and then add additional materials stored in the containers to adjust the batch as necessary. When the proper volume and ratio of feedstock and sugar have been inserted into the fermentation tank  103 , the lid  111  is closed. The lid  111  may have a locking mechanism to prevent the addition of any other materials to the tank  103  until after processing is completed. 
     As discussed, the system controller  151  detects the quantity of sugar in the fermentation tank  103  and calculates the corresponding volume of water for the fermentation process. The system can automatically add the volume of water required for fermentation processing to the tank  103 . The proper volume of water can be detected based upon a metered flow of water from a water storage tank  181 . Alternatively, the system controller  151  can detect the weight of the water and calculate the volume of water added based upon the known volumetric weight. The system controller  151  is coupled to a valve between the water tank  181  and the fermentation tank  103 . The system controller  151  can open the valve to cause water to flow into the tank  103  and when the proper volumetric weight change is detected, the system controller  151  can close the valve. In other embodiments, the water can be added to the fermentation tank  103  manually and the system will indicate when the proper quantity of water has been added. 
     With the proper mixture of water, feedstock and sugar in the fermentation tank  103  the system can mix the batch ingredients by rotating the agitator  107  to mix the materials. In an embodiment, a motor  109  is used to rotate shaft  115  coupled to an agitating element  107 . The agitating element  107  can be an elongated angled mixing blade that circulates liquids in the tank  103  when rotated. The mixing is required to cause the yeast in the feedstock to come in contact with the sugar and nutrients required for fermentation. While a single agitator  107  is illustrated, in other embodiments multiple agitators can be used to mix the materials and prevent clumping of the sugar and feedstock in the corners of the tank  103 . 
     In an embodiment, the control system  151  may detect the proper mixing of the batch materials by the rotational resistance of the agitator  107  or viscosity. A low resistance or viscosity indicates that the agitator  107  is only in contact with water while a higher resistance may indicate that the agitator  107  has contacted a clump of sugar or feedstock. The system can be configured to move the agitator  107  and the shaft  115  within the fermentation tank  103  to completely mix the batch materials. During the mixing process, the rotational resistance is an indication of the status of the mixing. The materials may be properly mixed when the rotational resistance is steady and corresponds to a proper resistance range for the mixture. Once the proper mixed viscosity is detected, the materials are properly mixed and the rotation of the agitator  107  can be stopped or run periodically during the fermentation process. 
     During the fermentation process, the yeast absorbs the sugar when diluted in water. This reaction produces 50% ethanol and 50% CO 2  by the end of the fermentation process. The chemical equation below summarizes the conversion: 
       C 6 H 12 O 6 (Glucose)=&gt;2CH 3 CH 2 OH(Ethanol)+2CO 2 +heat 
     In other embodiments, the micro refinery is able to process cellulosic materials to produce ethanol. Cellulosic ethanol is made from plant waste such as wood chips, corn cobs and stalks, wheat straw and sugarcane stalks, stems and leaves or municipal solid plant waste. An advantage for a cellulosic fuel production is that the micro refineries can be configured to process the regional crop plant material, reducing delivery costs. For example, the micro refineries located in the Midwest can be configured to process: wheat straw and corn residue. In the Southern United States the micro refinery can process sugarcane. In the Pacific Northwest and Southeast, wood can be converted into Ethanol. 
     Corn is easily processed because corn has starches that enzymes can easily break down into sugars and yeast ferments the sugars to produce ethanol. In contrast, cellulosic stalks and leaves contain carbohydrates that are tougher to break down and unravel because they are tightly bound with other compounds. Thus, special processing is required make ethanol from cellulosic farm waste. More specifically, special enzymes are needed in the fermentation tank to break down the carbohydrates. In addition to the special enzymes, the farm waste processing requires genetically engineered bacteria to ferment the farm waste sugars into ethanol. 
     Another problem with farm waste is that it can be mixed with earth matter such as rocks, clay and gravel that can damage the micro refinery components. In order to prevent damage, the cellulosic materials can be ground with a grinder to more finely chop the materials before processing. The cellulose materials are also separated into glucose and non-glucose sugars using a machine that applies heat, pressure and acid to the cellulosic materials. The heat and pressure produce a sugar and fiber slurry mixture. The non-glucose sugars are washed from the fibers and the glucose based fibers are processed with enzymes to break down and separate the sugars from the fibers. The separated sugars are then fermented with special bacteria microbes into a beer containing ethanol, water and other residue. After fermentation, the micro refinery vaporizes the beer so that the ethanol vapors rise up through a distillation tube to separate the ethanol from water. The vapor from the distillation tube is processed by a porous filter that is used to separate the ethanol vapor from any remaining water vapor as described above. 
     In another embodiment a different process is used to separate the glucose and non-glucose sugars. The mixture of glucose and non-glucose sugars can be separated, by mixing cellulosic materials with a solution of about 25-90% acid by weight. The acid at least partially breaks down the cellulosic materials and converts the materials into a gel that includes solid material and a liquid portion. The gel is then diluted from about 20% to about 30% by weight and heating the gel, thereby at least partially hydrolyzing the cellulose contained in the materials. The liquid portion can then be separated from the solid material, thereby obtaining a mixed liquid containing sugars and acids. The sugars are then separated from the acids in the mixed liquid by resin separation to produce a mixed sugar liquid containing a total of 15% or more sugar by weight and an acid content of less then 3% by weight. 
     The method of obtaining the mixed sugar further comprises mixing the separated solid material with a solution of about 25-90% sulfuric acid by weight, thereby further breaks down the solid material to form a second gel that includes a second solid material and a second liquid portion. The second gel liquid is diluted to an acid concentration of from about 20% to about 30% by weight. The diluted second gel liquid is then heated to a temperature between about 80° to 100° C., thereby further hydrolyzing the cellulose remaining in the second gel. The second liquid portion is separated from the second solid material to obtain a second liquid containing sugars and acid. The first and second liquids can be combined to form a mixed liquid. The glucose separation process is described in more detail in U.S. patent application Ser. No. 10/485,285 filed on Jan. 26, 2004, which is hereby incorporated by reference. The described process for producing ethanol from cellulosic materials has many benefits. Tree remains, lawn clippings and other plant debris are normally disposed of in landfill. By using these materials to produce ethanol, the land fill created is significantly reduced, the micro refinery has a substantially free source of feedstock and less greenhouse gases are produced. 
     A requirement of fermentation is proper temperature control to keep the ingredients within a proper fermentation temperature range. If the yeast temperature is too cold the yeast can become dormant and fermentation is slowed and if the temperature is too high the yeast can be killed. There are various types of yeast, some of which have a high temperature tolerance. The internal temperature of the fermentation tank  103  should be between about 60 and 90 degrees Fahrenheit to preserve yeast culture life. In order to increase the speed of fermentation, the temperature may be maintained at the higher end of the yeast tolerance temperature range. 
     In an embodiment, the system  101  also includes a thermoelectric mechanism  113  that can be coupled to the fermentation tank  103 . The thermoelectric mechanism  113  is powered by a DC electrical power supply and maintains the optimum processing temperature within the tank  103 . In order to provide uniform temperature control, a plurality of thermoelectric mechanisms  113  can be attached to various sections of the tank  103 . In an embodiment, the system controller  151  is coupled to the thermoelectric mechanism  113  and a temperature transducer is mounted within the fermentation tank  103 . The system controller  151  receives a signal corresponding to the internal tank temperature from the temperature transducer and determines if the fermentation tank  103  is within the proper temperature range or if the batch needs to be heated or cooled. As discussed above, the fermentation process produces heat, so in some cases heating or cooling of the tank  103  may not be required. If the system detects that the fermentation tank  103  is too cold, the system controller  151  applies direct current electrical power to the thermoelectric mechanism  113  in the heating mode of operation. If the temperature of the fermentation tank  103  is too hot, the thermoelectric mechanisms  113  can be switch to a cooling mode to reduce the temperature of the tank  103  by reversing the polarity of the electrical power to the thermoelectric mechanism  113 . The system controller  151  can also turn the power to the thermoelectric mechanism  113  off when the fermentation tank  103  temperature is within the proper or optimum temperature range for fermentation. The optimum temperature can depend upon the specific type of yeast being fermented but is typically between about 25° C. to 30° C. 
     In another embodiment, the system may utilize a pump  119  that pumps the batch through a thermoelectric radiator  117  that is separate from the fermentation tank and then returns the batch to the fermentation tank. If the system controller  151  detects that the batch is too cold, the pump  119  is actuated to pump the batch through the thermoelectric radiator  117  which is controlled by the controller  151  to heat the batch. Alternatively, if the system controller  151  detects that the batch is too hot, the pump  119  is actuated to pump the batch through the thermoelectric radiator  117  which is controlled by the controller  151  to cool the batch. The outlet of the thermoelectric radiator  117  can be coupled to the fermentation tank  103  so that all thermally processed batch materials are returned to the fermentation tank  103 . 
     In an embodiment, the system can be used in a wide variety of environments and has the ability to produce ethanol in a wide range of ambient conditions. This requires the cooling of the fermentation tank in hot regions and seasons and heating of the fermentation tank  103  in cold areas and seasons. A larger number of thermoelectric mechanisms  113  can be used in systems located in more extreme ambient temperatures. In an embodiment, the user can simply purchase and install additional thermoelectric mechanisms  113  to compensate for the hotter or colder temperatures. It is also possible to reduce the effects of extreme ambient temperatures by placing the micro refinery system within a protective enclosure and adding insulation to the micro refinery systems. 
     The thermoelectric mechanisms  113  can be mounted on the fermentation tank  103  walls or, as discussed above with reference to  FIG. 1 , the thermoelectric mechanisms can be configured as a thermoelectric radiator  117 . The fermentation liquid can be pumped through a thermoelectric radiator  117  to provide heating and cooling. Thus, the thermoelectric heating and cooling mechanism  113  and thermoelectric radiator  117  can cool the batch fermentation tank or heat the batch through the system controller  151  by reversing the DC polarity applied to the thermoelectric mechanisms  113  and thermoelectric radiator  117 . 
     In a preferred embodiment, the fermentation tank  103  holds about 200 gallons of liquid. The thermoelectric mechanisms  113  are practical for small fermentation batches in this liquid volume range, but lack enough thermal energy to perform thermal control of larger commercial fermentation processing. For these reasons, the thermoelectric mechanisms can be used with the inventive system to control the temperature of about 200 gallons of liquid but are not suitable for temperature control of a larger 1,000+ gallon commercial fermentation processing tank. 
     A problem with the fermentation process is that it is not always a predictable process. The time required to complete the fermentation process will vary depending upon the purity of the sugar, and yeast, as well as the batch temperature. One way to monitor the fermentation progress is by monitoring the change in weight of the fermenting liquid. During fermentation, the sugar is converted into ethanol and CO 2  which is vented out of the fermentation tank  103 . Thus, the venting of the CO 2  results in a weight reduction of the batch. In an embodiment, the force sensors  105  are used to periodically or continuously check the weight of the batch during the fermentation process. As CO 2  is vented from the fermentation tank  103 , the batch gets lighter. The system can monitor the progress of batch fermentation by monitoring changes in the weight of the batch. An initial weight of the batch can be determined and stored in memory. Changes in the batch weight are caused by the conversion of sugar into CO 2  which is vented from the fermentation tank  103 . The system controller  151  can determine that the fermentation process is complete when the weight of the batch is reduced by a known percentage. Alternatively, the system controller  151  can determine that the fermentation process is complete when the rate of weight reduction slows or stops. A CO 2  sensor can also be coupled to the fermentation tank. Since the CO 2  is vented, a low level of CO 2  in the tank  103  would indicate that less CO 2  is being produced by the batch. 
     As discussed above, the force sensors  105  can be used for detecting an initial start weight of the sugar, feedstock and water loaded into the tank  103  at the beginning of the fermentation process. The weight can then be detected periodically by sampling the force sensors  105  at time intervals. By monitoring the weight of the batch over time, the rate of weight change over time can be used to determine the stage of the batch in the fermentation process. At the beginning of the process, the weight of the batch drops fairly quickly. As the conversion of the sugar to ethanol progresses, the rate at which the weight decreases slows. Eventually, the weight change becomes very low indicating that the fermentation process is complete. 
     In addition to detecting the weight of the batch, the system can also perform chemical detection of the batch ingredients. In an embodiment, the micro refinery includes a batch testing mechanism  171  shown in  FIG. 1 , which can detect the chemical components of the batch and may include an optical, electrical, chemical or any other type of chemical sensor. A delivery mechanism may include a tube  175  that is coupled to a pump  173  to deliver samples of the batch to the testing mechanism  171 . The testing mechanism  171  can be coupled to the controller  151  and can be used to check the chemical balance of the batch during the fermentation process. The detected quantity or ratio of batch components from the test mechanism  171  is compared to an optimum value which can be stored on a look up table or provided by another source. The optimum ratio of the batch components can change during fermentation. If there is a significant difference between the measured and optimum values, the controller  151  can transmit a signal indicating the problem and/or the controller  151  may automatically add chemical components to the fermentation tank  103  to rebalance the batch. By continuously testing and adjusting the batch throughout the fermentation process, the ethanol production from the batch can be maximized. More specific examples and descriptions of the sensors used in the chemical testing mechanism are described later. 
     Although the fermentation tank  103  has been described above for fermenting sugar and feedstock, the inventive system also has the ability to process different materials and can extract ethanol from recycled alcoholic beverages such as beer, wine and other alcohol products. The user can select the function of the micro refinery system as either a sugar fermentation tank or a processor of discarded alcohol. In the sugar fermentation mode, the micro refinery system ferments the sugar to create alcohol as described above. In the alcohol recycling mode, the alcoholic products also go into the fermentation tank prior to being processed by a distillation system for conversion into ethanol. The multi-function design provides a market advantage for recycling either sugar or discarded alcohol commonly found at bar restaurants or wineries. 
     After or during the fermentation of the sugar, it is possible to add the alcoholic liquids to the fermentation tank. The processor can indicate when alcoholic beverages can be added. In an embodiment, the controller can actuate a locking mechanism coupled to the lid  111  to allow or prevent the user from adding materials to the fermentation tank  103 . Because the reaction of the yeast has converted much of the liquid into carbon dioxide, the volume of liquids in the fermentation tank  103  will decrease after fermentation is complete which allows room for recycling the alcoholic beverages. The micro refinery will then separate the ethanol from the batch as well as the alcohol from the discarded beverages and the other liquid components. 
     The ethanol is separated from the water and other liquids by processing the fluids through a distillation system. In an embodiment, the distillation system of the present invention includes a pump  127 , a heater  129 , a distillation tube  131  and a gimbaled mechanism  139  that is used to position the distillation tube  131  in a vertical orientation. The vertical orientation can be maintained by a gyroscope  132  mounted to the distillation tube  131 . The gyroscope  132  includes a rotor that can be aligned with the vertical axis of the distillation tube and a motor that rotates the rotor. The rotation of the rotor stabilizes the gyroscope  132  and distillation tube from any rotational movement. The control system  151  controls the pump  127  to pump the liquids in the fermentation tank  103  through the heater  129  to cause the water and ethanol to boil and vaporize. As discussed above, heat can be transferred to the heater  129  through a heat exchange loop to improve the efficiency. The vaporized liquid is directed to the bottom of the distillation tube  131 . As the vapors travel higher through the distillation tube  131 , the ethanol molecules separate from the water molecules and exit the upper part of the column. If water and other non-ethanol liquids vaporize, these vapors will tend to be condensed on the sides of the distillation tube as they cool in the distillation tube  131 . The condensed liquids may then adhere or drip down the inner walls of the distillation tube  131  rather than exiting the top of the tube  131 . The distillation system may also include one or more temperature sensors which monitor the vapor temperature and control the heater  128  to produce vapor at an optimum separation temperature. Excessive heat will cause a faster vapor velocity resulting in more water exiting the distillation tube  131 , while a low temperature vapor temperature will result in a low flow of ethanol from the distillation tube  131 . 
     For optimum distillation performance, the heater  129  can heat the fluids to a constant temperature that results in an optimum vaporization rate for the ethanol while the water and other non-ethanol vapor condenses on the sidewalls of the distillation tube  131 . The operation of the distillation column  131  can be monitored by a liquid level sensor. With reference to  FIG. 2 , a side view of a liquid level sensor  801  at a lower portion of the distillation tube  131  is illustrated. In an embodiment, the distillation system can also include a closed loop internal electromechanical float circuit at the base of the distillation tube  131  that can measure the level of fluid  834  so the heating source can be adjusted. The liquid level sensor can include a float  803  that includes a permanent magnet. The float  803  has positive buoyancy so it will always remain on the surface of the fluid  809 . The float  803  surrounds a magnetic sensor tube  805  that includes magnetic sensors that detect the vertical position of the float  803 . As the fluid  809  level changes, the float  803  moves up and down around the magnetic sensor tube  805 . 
     The magnetic sensor tube  805  can be coupled to a controller  881  that controls the pump  127  and heater  129  to maintain the proper vaporization temperature within the distillation tube  131 . If excessive fluid  834  accumulates at the bottom of the distillation tube  131 , the power to the heat  129  can be increased to accelerate the vaporization. Conversely, if there is very little fluid  834  at the bottom of the distillation tube  131 , the heat can be reduced to slow the vaporization rate. Ideally, the fluid  834  is heated to a constant temperature for optimum vaporization to occur. If the temperature is not maintained properly, the column vapor, pressure and quality of existing fuel can become unstable. 
     A potential problem with the liquid level sensor illustrated in  FIG. 2  is that the fluids  834  can include many impurities and may become sticky or contain disruptive material that can adhere to the float  803  or magnetic sensor tube  805  obstructing the movement of the float  803 . If the float  803  becomes stuck, this can result in errors in the liquid  834  level detection. This error can cause the external distillation control system to become unstable or stop functioning all together. The sensor mechanism can be cleaned, however, this would require disrupting the operation of the system. 
     With reference to  FIG. 3 , an alternative improved float level sensor is illustrated. In this embodiment, the float  903  mechanism surrounds a very thin guide wire  905  and a magnetic sensor  907  is coupled to an outer wall of the distillation tube  131  that extends vertically along a lower portion. The float mechanism includes a permanent magnet that is horizontally aligned and can emit a north magnetic field towards the wall of the distillation tube  131 . The magnetic sensor  907  can detect the position of the north magnetic field and based upon this information the liquid  834  level within the distillation tube  131  can be determined. In this embodiment, the base of the distillation tube  131  must also be made from non metallic materials to allow the magnetic signals from the float  903  to penetrate the external parameter of the column. 
     With reference to  FIG. 4 , another embodiment of the float level sensor is illustrated. In this embodiment, the float mechanism  971  is placed within a vertical cage  977 . The illustrated example includes six vertical members  973  that define the cage  977 . However, in other embodiments, the cage  977  can include three or more thin vertical members  973  that are arranged in a circular pattern around the float  971  to keep the float  971  within the cage  977 . The vertical members  973  are parallel to each other and extend along the bottom of the distillation tube  131 . A magnetic sensor  977  is coupled to an outer wall of the distillation tube  131  and extends vertically along a lower portion. The float mechanism  971  can be an egg or spherical shaped structure that is buoyant and contains a permanent magnet that is horizontally aligned and can emit a north magnetic field towards the wall of the distillation tube  131 . Like the embodiment illustrated in  FIG. 3 , the magnetic sensor  977  can detect the position of the north magnetic field and based upon this information, the sensor  977  can determine the liquid  834  level within the distillation tube  131 . The base of the distillation tube  131  must also be made from non metallic materials to allow the magnetic signals from the float  903  to penetrate the external parameter of the column. 
     The wire embodiment illustrated in  FIG. 3  and the cage embodiment illustrated in  FIG. 4 , have several advantages over the tube sensor embodiment illustrated in  FIG. 2 . Both the wire and cage embodiments have substantially less mass and friction than the tube embodiment. High friction can prevent the movement of the float due to fluid and other particles that can adhere to the sensor tube  805  illustrated in  FIG. 2 . In contrast, the guide wire  905  illustrated in  FIG. 3  has substantially less surface that particles can accumulate on. Also, since the float  903  does not have to have a tight fit around the guide wire  905 , the inner diameter of the float  903  can be much larger than the diameter of the guide wire  905 . For example, the inner diameter can be twice as large as the diameter of the guide wire  905 . Similarly, the cage  977  illustrated in  FIG. 4  has very little contact area with the float  971 . If particles adhere to the cage  973 , the float  971  can move within the cage  973  to provide more clearance so that the float will still move vertically with the fluid  834  level. 
       FIG. 5  illustrates a top view of the tube sensor embodiment,  FIG. 6  illustrates a top view of the wire sensor embodiment and  FIG. 7  illustrates a top view of the cage sensor embodiment. There is a larger contact area between the float  803  and the tube  805  in the tube embodiment shown in  FIG. 5 , than the float  903  and wire  905  shown in  FIG. 6  or the float  971  and cage  973  illustrated in  FIG. 7 . Because there is very little contact area in the wire and cage embodiments, there is a less space for fluid  834  or other particles to adhere to. Another advantage of the wire and cage embodiments is the external magnetometer  907  provides better measurement resolution and cannot be damaged by the harsh internal environment at the base of the distillation tube  131 . 
     To further improve the performance of the liquid level sensors illustrated in  FIGS. 2-7 , the sliding parts can be made of a smooth and slippery material such as Teflon or stainless steel that is coated with a lubricious material. Because the material is very smooth and self lubricating, the fluid  834  particles will not be able to adhere to any of the exposed surfaces. If any particles do stick to the guide wire  905  or tube  805 , the weight or buoyancy of the float  903  will tend to knock these pieces of material off of the guide wire  805 . The internal surface of the floats  803 ,  903  can also be a very smooth surface that from a self lubricating material. 
     With reference to  FIG. 1  again, the distillation process requires that the distillation tube  131  be in a perfect vertical alignment. The vapors slowly rise vertically straight up and the flow path is preferably undisturbed by sidewalls as the vapors travel up through the center of the distillation tube  131  and out from the top. If the distillation tube  131  is out of alignment, the rising vapors will run into the side of the tube  131  resulting in condensation of ethanol vapors and reducing the efficiency of the distillation system. Similarly, water vapor rising on the side wall tilted away from vertical may not condense on the sidewalls reducing the separation of the water and ethanol. Thus, perfect vertical alignment is necessary for the high efficiency distillation. 
     In an embodiment, a gyroscope  132  shown in  FIG. 1  is mounted to the bottom of the distillation tube  131 . The gyroscope  132  includes a rotor and a motor that rotates the rotor. Because the weight of the gyroscope  132  is supported by the distillation tube  131 , the center of gravity of the gyroscope  132  can be aligned with the vertical center axis of the distillation tube  131  so the weight will not cause misalignment. The rotational axis of the rotor can be aligned with the vertical axis of the distillation tube and while the rotor is rotating the gyroscope  132  and distillation tube  131  are stabilizes so that any angular motion of the micro refinery will not alter the vertical alignment of the distillation tube. In an embodiment, a distillation tube  131  is vertically aligned before the gyroscope is turned on and the rotor starts spinning. 
     The distillation tube  131  can be fragile and in some cases it may be desirable to lock the distillation tube  131  in place to prevent movement. In an embodiment, the vertical alignment system includes a locking mechanism that prevents the distillation tube from rotating. In an embodiment, the system can detect ambient conditions through sensors such as wind meters and/or accelerometers coupled to the housing. If the wind speed is very high, the system may move which will cause the distillation tube to move out of vertical alignment. Rather than risking damage to the distillation tube, the system may have a “safe” mode that can be actuated when predetermined wind speed or acceleration movement is detected. For example, the micro refinery may go into a safe mode with the distillation tube and other fragile system components locked in a safe position, when the detected winds are greater than 40 MPH are detected or an earthquake greater than 5.0 is detected. The system may also receive weather warnings for its geographic location from an outside source such as the internet weather information services and respond to storm warnings by scheduling safe mode times. The controller may also shut off power and/or provide surge protection to prevent damage to the electrical components due to power surges or power outages. 
     In an embodiment, the distillation tube can be filled with material packing or horizontal perforated plates which are used to strip vaporized beer from the alcohol. Ideally, the vaporized beer and ethanol enter the bottom of the distillation tube and the combined vapor travels up the tube. Water and other heavier material are blocked by packing or plates. In contrast, the ethanol will tend to stay in vapor form and continue to travel up the distillation tube. This helps to separate the water and other contaminants from the ethanol vapor. The plates can be horizontally oriented within the tube and multiple plates can be positioned along the length of the distillation tube. A potential problem occurs when the micro refinery temporarily stops production. The water will condense or evaporate and the beer can remain on the packing or perforated plates causing clogging of the perforations or packing when the system is used again. The entire condensation tube may need to be cleaned before the system can be used again. 
     During the normal operation of the micro refinery, the hot ethanol and water vapors exit the distillation tube  131  and travel through a membrane system  135  which separates water molecules from the ethanol molecules. The membrane system  135  includes a porous separation membrane that can be made of ceramic, glass or very course materials. 
     A potential problem with the porous membrane system is that the membrane materials can be susceptible to this thermal damage. In particular, “thermal damage” of the membrane can occur if the temperature of the ethanol vapor is substantially hotter than the membrane. For example, the membrane may be at ambient temperature and then immediately exposed to hot ethanol vapor resulting in damage. To prevent thermal damage of the membrane a micro controlled warming system is used to pre-heat the membrane to ensure the membrane temperature is suitable for processing the hot vapor. In an embodiment, the temperature of the membrane is detected by a thermocouple attached to the membrane system. As the control system directs the flow of fluids out of the fermentation tank through to the heater and distillation tube, it detects the temperature of the membrane before the hot vapors are directed to the distillation tube. With reference to  FIG. 1 , if the membrane is cold, the system controller  151  can activate a heating element and monitor the membrane temperature. As the membrane temperature increases, the control system may have a thermostatic setting to prevent over heating of the membrane by the heater. When the membrane temperature is pre-heated to a safe temperature, the system controller  151  can allow hot vapors to flow through the distillation tube  131  to the membrane. Once the hot vapors are flowing through the membrane, the vapors will heat the membrane and power to the heating element can be removed. In order to assist with the ethanol and water separation process, the water vapor can be drawn through the porous membrane with a vacuum  143 . 
     In an embodiment, the membrane system  135  can have a back up membrane  135 . If one membrane system  135  is damaged, the controller will detect the failure and the controller  151  can actuate a valve  136  to divert the water and ethanol vapors from the distillation tube  131  to the back up membrane system  135 . The controller  151  can transmit a signal indicating that the membrane  135  is damaged through the transceiver  197  to an operator or maintenance group. The damaged membrane system  135  can then be replaced while the water and ethanol vapors are separated by the backup membrane system  135 . 
     After passing through the membrane system  135  and vacuum  143 , the water can condense and flow into the water storage tank  181  before being used again in the fermentation tank  131 . The separated ethanol exits the membrane system  135  and then flows through a thermo-electric cooler  166  which causes the ethanol to condense into a liquid. The liquid ethanol then flows into a storage tank  145  where it is stored before being mixed with gasoline. An ultrasonic or other liquid sensor coupled to the storage tank  145  can detect the liquid ethanol level within the storage tank  145  and provide this ethanol production information to the system controller  151 . In an embodiment, the system controller  151  can detect when the ethanol storage tank  145  is full and stop the distillation process until there is available space in the storage tank  145 . 
     In an embodiment, the inventive micro refinery can mix the ethanol stored in the ethanol storage tank  145  with gasoline that is stored in a gasoline storage tank  155  in any ratio set by the user through the system controller  151 . The control system includes a user interface which allows the user to select the desired fuel blend ratio. The system may include a lock that prevents the fuel mixture setting to exceed the maximum or minimum allowable ethanol percentage for the vehicle. Once the fuel mixture has been selected, the user can use the micro refinery functions like a normal gasoline pump. The user removes the nozzle  163  from a cradle on the micro refinery  101  and places it in the tank filler of the vehicle. A lever coupled to the nozzle  163  is actuated to start the pumps  149  which cause the fuel to flow from the tanks  145  and  155  through the hose reel  157 , the hose  161  and nozzle  163  to the tank of the vehicle. The system will run the ethanol and gasoline pumps  149  at different flow rates to produce the specified fuel ratio. The nozzle  163  will detect when the vehicle tank is full and automatically stop the flow of fuel through the nozzle  163 . When the vehicle tank is full, the user places the nozzle  163  back in the cradle and replaces the cap on the fuel filler to end the filling process. With the ethanol tank  145  at least partially drained, the system can begin to produce more ethanol. 
     The mix ratio of ethanol and gasoline or other fuels can depend upon the type of vehicle being fueled. The use of pure ethanol in internal combustion engines is only possible if the engine is designed or modified for that purpose. However, ethanol can be mixed with gasoline in various ratios for use in unmodified automobile engines. In the United States, normal cars designed to run on gasoline may only be able to use a blended fuel containing up to 15% ethanol. In contrast, U.S. flexible fuel vehicles can use blends that have less than 20% ethanol or up to 85%. The ethanol fuel blend is typically indicated by the letter “E” followed by the percentage of ethanol. For example, typical ethanol fuel names include: E5, E7, E10, E15, E20, E85, E95 and E100, where E5 is 5% ethanol and 95% gasoline, etc. 
     After the processing performed by each of the micro refinery systems is complete, the micro refinery systems may also be cleaned. In an embodiment, the micro refinery includes cleaning mechanisms that can spray the fermentation tank with pressurized soap and water which will remove particulates from the tanks and other components. The system can then rinse the system components to remove the soap and other residue. In an embodiment a drain valve is opened to allow the waste liquids from the fermentation tank and the distillation system to drain from the system through a drain hose. The system may include an automated cleaning system that utilizes valves coupled between a water supply and a spray nozzle that emits high pressure water and is actuated by the system controller. The spray can be directed towards the fermentation chamber walls to remote deposited materials. As the volatile materials have been removed from the interior surfaces of the micro refinery, a drain valve is opened and the waste materials can be poured down into public drainage systems. 
     Because the micro refinery is a complex mechanism, sensors and controls are used to automate the operation and optimize the ethanol production performance. The micro refinery can include various sensors that monitor the operating conditions of the processing systems including: the fermentation tank, the load cell weight detection system, the temperature control system, the mixing agitator for the fermentation tank, the distillation system, the membrane separation system, the storage tank and a blending and pumping system. All of these systems include sensors that are coupled to the controller. 
     It will be understood that the inventive system has been described with reference to particular embodiments, however additions, deletions and changes could be made to these embodiments without departing from the scope of the inventive system. For example, the same processes described can also be applied to other devices. Although the systems that have been described include various components, it is well understood that these components and the described configuration can be modified and rearranged in various other configurations.