Patent Publication Number: US-2006000357-A1

Title: Method and system for producing inert gas from combustion by-products

Description:
PRIORITY INFORMATION  
      The present application is based on and claims priority to U.S. Provisional Patent Application No. 60/555,793, filed Mar. 23, 2004, the entire contents of which is hereby expressly incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTIONS  
      1. Field of the Inventions  
      The present inventions are directed to systems and methods for generating inert gas, and more particularly, systems and methods for producing inert gas from combustion byproducts.  
      2. Description of the Related Art  
      In the art of drilling, such as drilling for oil or natural gas, inert gases are commonly used for numerous purposes. Typically, inert gases are often used to displace oxygen from the volume of space above a liquid surface in a storage tank used for storing flammable substances, such as, for example, crude oil. Additionally, inert gases are often used to suppress fire or explosion and prevent corrosion during a drilling operation.  
      Inert gas may also be used during a drilling operation. For example, an inert gas such as nitrogen, can be injected into a borehole during a drilling operation to prevent ignition of substances within the borehole and to prevent corrosion of the drill bit.  
     SUMMARY OF THE INVENTIONS  
      An aspect of at least one of the embodiments disclosed herein includes the realization that gas separation units, such as those used for separating nitrogen from air, can be converted into a high-purity, compact, and portable inert gas generators by including an air/fuel engine that provides shaft power for driving the separating device as well as supplies oxygen-reduced exhaust gas to the separation unit. In such an arrangement, the air/fuel engine performs the dual purposes of providing shaft power for the separation unit and reducing the oxygen content of the gases fed into the separation unit. As such, a further advantage can be achieved by disposing an air/fuel engine and a separation unit in a common assembly, such as, for example, but without limitation, a skid mounted unit, an ISO container sized-unit, or other portable assemblies. As such, the entire unit can be transported, started and used with greater speed, thereby reducing the time necessary for beginning a drilling operation or other types of field operations.  
      In accordance with one embodiment, a method for producing inert gas is provided. The method includes operating a combustion engine so as to produces an exhaust gas, the exhaust gas comprising non-inert gas and inert gas, the volume percentage of non-inert gas of the exhaust gas is less than the volume percentage of non-inert gas of ambient air. The method also includes using power from the combustion engine to compress the exhaust gas and separating a portion of the inert gas from the non-inert gas contained in the exhaust gas.  
      In accordance with another embodiment, a system for producing inert gas comprises an air/fuel engine having an exhaust outlet, a compressor having a compressor outlet and an inlet communicating with the exhaust outlet. The compressor is powered by the engine and is configured to compress exhaust gas from the engine. A separation device includes a separation inlet communicating with the compressor outlet and is configured to separate inert and non-inert gases from the exhaust.  
      In accordance with yet another embodiment, a system for producing inert gas comprises a compressor having a compressor outlet and an inlet, the compressor being configured to compress source gas. A separation device includes a separation inlet communicating with the compressor outlet and is configured to separate inert and non-inert gases from the source gas. The system also includes at least one single means for providing both source gas and power to the compressor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic view of a drilling stem arrangement showing delivery of an inert gas to a downhole drilling region.  
       FIG. 2  is a cross-sectional schematic view of a well with a horizontally disposed section including casings and upper and lower liners with an inert rich gas present therein.  
       FIG. 3  is a cross-sectional schematic view of an initial injecting of a cement slurry for cementing a casing within a well.  
       FIG. 4  is a cross-sectional schematic view of the casing of  FIG. 3  with the cement in place to secure the casing within the well.  
       FIG. 5  is a cross-sectional schematic view of a well and equipment for removing gas and/or oil from a well with the assistance of an inert rich gas.  
       FIG. 6  is a cross-sectional schematic view of a reservoir and the injection of an inert rich gas to remove gas and/or oil from the reservoir.  
       FIG. 7  is a schematic diagram of an embodiment of an inert gas separation system in which exhaust from an engine is subjected to a separation process to separate inert gas therefrom.  
       FIG. 7A  is a schematic illustration of an embodiment of the separation system of  FIG. 7 .  
       FIG. 7B  is a schematic illustration of an embodiment of the separation system of  FIG. 7 .  
       FIG. 7C  is a schematic illustration of another embodiment of the separation system of  FIG. 7 .  
       FIG. 8  is a schematic diagram of another embodiment in which exhaust from an engine is subjected to a separation process to produce inert rich gas therefrom. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      The present embodiments generally relate to an improved system and methods for producing inert gases. The systems and methods for producing inert gases are generally described in conjunction with the production of inert gas, such as nitrogen gas (N 2 ), for use during a drilling operation because this is an application in which the present systems and methods have particular utility. Additionally, the systems and methods can be used to produce inert gas having different levels of purity. Those of ordinary skill in the relevant art can readily appreciate that the present systems and methods described herein can also have utility in a wide variety of other settings, for example, but without limitation, offshore drilling rigs as discussed in greater detail below.  
       FIG. 1  is a schematic view of a typical drill stem arrangement  18  showing the delivery of an inert rich gas to a downhole drilling region  19 . Generally, inert rich gas flows down the drill stem arrangement  18  until it reaches a drill stem assembly  20  which is typically connected in lengths known as “pipe stands”. The drill stem assembly  20  can be fed through the well head assembly (identified generally by numeral  22 ) which may contain a series of pipe rams, vents, and choke lines. The inert rich gas is exhausted through an outlet  24  which is connected to a blooey line.  
      For non-drilling applications, the drill stem assembly  20  may be removed and the inert rich gas can be pumped into the downhole region through the pathway  26 .  
      The surface installation may optionally include an injector manifold (not shown) for injecting chemicals, such as surfactants and special foaming agents, into the inert rich gas feed stream, to help dissolve mud rings formed during drilling or to provide a low density, low velocity circulation medium of stiff and stable foam chemicals to cause minimum disturbance to unstable or unconsolidated formations.  
      Extending below the surface of the ground into the downhole region is the drill stem arrangement  18  which provides a pathway for the flow of pressurized inert rich gas to the drilling region. There is also provided a second pathway for the flow of nitrogen gas and the drill cuttings out of the downhole region and away from the drilling operation.  
      With continued reference to  FIG. 1 , the drill stem arrangement includes an outlet or surface pipe  24 , a casing  32 . The drill stem assembly  20  extends concentrically with and spaced apart from the surface pipe  24  and production casing  32  so as to define a pathway  42  for the return of inert rich gas and the drill cuttings. The center of the drill stem assembly  20  provides a pathway  26  for the flow of inert rich gas to the drilling region. At the lower end  75  of the drill stem arrangement  18 , in vicinity of the lower drilling region  34 , is a conventional tool joint  35 , a drill collar  36  and a drill bit  38 .  
      The inert rich gas (e.g., nitrogen rich gas) is typically pressurized by a compressor and is then delivered to the drill stem assembly  20 . Because the inert rich gas is under pressure, it can swirl around the drilling region  34  with sufficient force and velocity to carry the drill cuttings upwards into the pathway  42 . The drill cutting containing stream then exits the outlet  24  of the surface installation equipment where it is carried to a blooey line and eventually discarded into a collection facility, typically at a location remote from the actual drilling site.  
      The inert rich gas described above for removing drilling cuttings can also be injected into the drilling fluid to reduce the density thereof. This provides greater control over the drilling fluid and is particularly adapted for “under balanced” drilling where the pressure of the drilling fluid is reduced to a level below the formation pressure exerted by the oil and/or gas formation. The inert rich gas can be provided to the drilling fluid in the following exemplary but non-limiting manner.  
      With continued reference to  FIG. 1 , the inert rich gas can be injected into a drilling fluid through an assembly shown in  FIG. 1  absent the drill stem assembly  20 . In one embodiment, the inert rich gas is pumped through the pathway  26  which can be in the form of linear pipe strings or continuous coiled tubing known as a “drill string”. Alternatively, the inert rich gas can be pumped into the annular space  42  between the drill string or pathway  26  and the casing  32  inserted into the well. In this embodiment a drill string can be inserted directly into the annular space  42  to provide the inert rich gas directly therein. As such, the inert rich gas can be used to modify the flow properties and weight distribution of the cement used to secure the casings within the well.  
      With reference to  FIGS. 2, 3  and  4 , a well  44  is supported by tubular casings including an intermediate casing  88 , a surface casing  50 , and a conductor casing  48 . The conductor casing  48  is set at the surface to isolate soft topsoil from the drill bit so as to prevent drilling mud from eroding the top section of the well bore.  
      The surface casing  50  also extends from the surface of the well and is run deep enough to prevent any freshwater resources from entering the well bore. In addition to protecting the fresh water, the surface casing  50  prevents the well bore from caving in and is an initial attachment for the blow-out-prevention (BOP) equipment. Typical lengths of the surface casing  50  are in the range of from about 200 to 2500 ft.  
      The intermediate casing  88  protects the hole from formations which may prove troublesome before the target formation is encountered. The casing  88  can be intermediate in length, i.e., longer than the surface casing  50 , but shorter than the final string of casing (production casing)  32 .  
      The production casing (oil string or long string) extends from the bottom of the hole back to the surface. It isolates the prospective formation from all other formations and provides a conduit through which reserves can be recovered.  
      The diameter of the various casings  48 ,  50 ,  88  decreases as the depth of the casing into the well  44  increases. Accordingly, the intermediate casing  88  extends the furthest into the well  44 . The intermediate casing  88  is typically filled with a drilling fluid  58  such as drilling mud.  
      The process of securing the casing within the well using a cement-like material is illustrated in  FIGS. 3 and 4 . With reference to  FIG. 3 , a well  44  contains a casing  60  which is initially filled with a drilling fluid  58  such as drilling mud or a drilling mud modified with a nitrogen rich gas. A wiper plug  62  is inserted into the casing  60  and urged downward to force the drilling fluid out of the bottom opening  65  and up along the annular space  64  between the walls  66  defining the well bore and the casing  60 . The drilling fluid proceeds upwardly through the annular space  64  and out of the opening  70  at the top of the well  44 .  
      While the drilling fluid is being evacuated a cement-like material in the form of a slurry is loaded into the casing  60 . A second wiper plug  66  is then urged downwardly as shown in  FIG. 4  to force the cement out of the bottom opening  65  until the annular space  64  is filled. Excess cement escapes out of the opening  70  of the well.  
      An inert rich gas, preferably nitrogen gas, which can be produced as described below, can be used to reduce the density of the cement in a manner similar to that described for the drilling fluid. The inert rich gas can be injected into the casing while the cement is being added therein. The injection of the inert rich gas into the cement modifies the density and flow characteristics of the cement while the cement is being positioned in the well.  
      The inert rich gas is injected into the casing through a drill string of the type described in connection with  FIG. 1  with the drill stem assembly  20  removed. The rate of injection and the precise composition of the inert rich gas is controlled by a compressor.  
      The inert rich gas can be used to improve the buoyancy of the casings so as to minimize the effects of friction as the casings are inserted into the well. This is particularly apparent when casings are inserted into horizontal sections in the downhole region. In horizontal sections, the weight of the casing causes it to drag along the bottom surface of the wellbore. In extreme cases the casing may become wedged in the wellbore and not be able to be advanced as far into the downhole region as desirable. Introducing an inert rich gas into the interior of the casing will increase the buoyancy of the casing, allowing it to float in the mud or drilling fluid surrounding the casing.  
      With continued reference to  FIG. 2 , there is shown a casing assembly including a tubular member or liner  68  which is designed to enter a horizontal section  70  of the well  44 . The liner  68  is any length of casing that does not extend to the surface of the well.  
      The liner  68  includes an upper section  72  which contains a drilling fluid and a lower section  73 . The upper and lower sections are separated by an inflatable packer  74 . The lower section  73  is charged with the inert rich gas which makes it lighter and more buoyant than the upper section  72  which is filled with mud. The lower section  73  may therefore move easily into the horizontal section  70  of the well  44 .  
      After the completion of drilling in the downhole region, inert rich gas can be used to improve well performance and maximize output of gas and/or oil from the reservoir. Quite often well production declines because of the presence of fluids, such as water, excess drilling mud and the like in the downhole region. The inert rich gas can be used to clean out the well by displacing the heavier fluids that collect therein. Removal of the heavier fluids will regenerate the flow of gas and/or oil from the reservoir if there is sufficient formation pressure within the reservoir. The inert rich gas can be used to provide an additional boost for lifting the gas and/or oil from the downhole region to a collection area. In this case the inert rich gas is pumped down into the downhole region within the casing under sufficient pressure so that the gas and/or oil entering the downhole region from the reservoir is lifted upwardly and out of the well.  
      With reference to  FIG. 5 , there is shown an assembly particularly suited for injecting an inert rich gas into the gas and/or oil within the downhole region to facilitate delivery thereof upwardly through the well for collection. Such a system is applicable to downholes having reduced formation pressure. As a result the gas and/or oil has difficulty entering the downhole from the reservoir.  
      The inert rich gas can be injected into the annulus  80  between the casing  84  and a tubing  86 . The inert rich gas is metered into the tubing  86  through a valve assembly  88 . The tubing  86  has an opening  90  enabling gas and/or oil from the downhole region to enter and rise up to the surface of the well. The injection of the inert rich gas from the valve assembly  88  into the tubing  86  assists the gas and/or oil by providing buoyancy to the flow upwardly to the above ground collection area  94 . This process is commonly referred to as artificial gas lift.  
      In another application for inert rich gas, the nitrogen rich gas is used to stimulate the well in the downhole region to enhance gas and/or recovery. More specifically, the walls of the wellbore in the downhole region characteristically have cracks or fissures through which the gas and/or oil emerges from the reservoir. As the pressure in the reservoir decreases, the fissures begin to close thereby lowering production. The most common form of stimulating the downhole region is by acidizing or fracturing the wellbore. The inert rich gas can be used as a carrier for the acid to treat the wellbore. The inert rich gas expands the volume of the acid, retards the reaction rate of the acid resulting in deeper penetration and permits faster cleanup because there is less liquid to be displaced by the high energy inert rich gas.  
      Cracking of the wellbore in the downhole region can be performed by pumping a fluid such as acid, oil, water or foam into a formation at a rate that is faster than the existing pore structure will accept. At sufficiently high pressures, the formation will fracture, increasing the permeability of the downhole. When the stimulation procedure is completed, the pressure in the formation will dissipate and the fracture will eventually close. Sand and/or glass beads or other so-called “poppants” may be injected into the formation and embedded in the fractures to keep the fractures open. The inert rich gas may be used as a carrier gas to carry the poppants to the wellbore.  
      It is well established that the pressure in a reservoir (formation pressure) provides for the flow of gas and/or oil to the downhole region. As the reserves of gas and/or oil become depleted, the formation pressure decreases and the flow gradually decreases toward the well. Eventually the flow will decrease to a point where even well stimulation techniques as previously described will be insufficient to maintain an acceptable productivity of the well. Despite the reduced formation pressure, nonetheless, the reservoir may still contain significant amounts of gas and/or oil reserves.  
      In addition, gas-condensate reservoirs contain gas reserves which tend to condense as a liquid when the formation pressure decreases below acceptable levels. The condensed gas is very difficult to recover.  
      The lack of formation pressure in a reservoir can be remedied by injecting an inert rich gas directly into the reservoir. As illustrated highly schematically in  FIG. 6 , an inert gas generation system is shown generally by numeral  210 . The assembly is constructed above a gas and/or oil reservoir  102 . Inert rich gas is pumped down the well, often called an injector well  44   a , through a tubing  104  to exert pressure on the reserves in the direction of the arrow. The increased pressure on the gas and/or oil causes the same to flow to a producing formation and up a producing well  44   b  through a tubing  106  into an above ground collection vessel  108 .  
      The flow rate of inert rich gas to the drilling region of an oil and/or gas well or a geothermal well can vary over a wide range depending on the size of the downhole, the depth of the well, the rate of drilling, the size of the drilling pipe, and the makeup of the geologic formation through which the well must be drilled. Some typical drilling operations require the production of from 1,500 to 3,000 standard cubic feet per minute (scfm) of nitrogen gas from the inert gas separation system  210 , however, other flow rates can also be used. The inert rich gas can be pressurized up to a pressure of from about 1,500 to 2,000 psig before being passed to the drilling region, however, other pressures can also be used.  
      An average drilling operation can take about five days to two weeks, although difficult geologic formations may require several months of drilling. The inert rich gas delivery system is designed for continuous operation and all of the inert rich gas is generated on-site without the need for external nitrogen replenishment required for cryogenically produced liquid nitrogen delivery systems.  
      In a typical underbalanced drilling operation, 500 to 800 scfm (standard cubic feet per minute) of an inert rich gas is commingled with drilling mud to reduce the hydrostatic weight of the drilling fluid in the downhole region of a well. This reduces or prevents an overbalanced condition where drilling fluid enters the formation, or mud circulation is lost altogether. Carefully adjusting the weight of the drilling fluid will keep the formation underbalanced, resulting in a net inflow of gas and/or oil into the well.  
      If a drill string becomes stuck due to high differential pressure caused by combined hydrostatic and well pressure conditions, an inert rich gas at 1500-3000 scfm at pressures of 1000-2000 psig can be injected down the drill string to force the fluid up the annulus to the surface. The reduced weight and pressure will help free the stuck pipe. In this case, the inert rich gas is used as a displacement gas.  
      A naturally producing reservoir loses pressure (depletes) over time with a resulting loss in recoverable oil and/or gas reserves. Injection of nitrogen at 1500 scfm or greater at various locations or injection sites will keep the reservoir pressurized to extend its production life. In gas condensate reservoirs, the pressure is kept high enough to prevent gas condensation or liquification, which is difficult to remove once liquified.  
      The inert rich gas can be introduced into the producing wells by means of special valves in the production casing positioned in the downhole region of the well. The lifting action of the inert rich gas is one form of artificial gas lift as shown best in  FIG. 5 .  
      It is contemplated that inert gas, such as nitrogen rich gas (N 2 ), can be used for various applications. For example, the inert gas can be used in manufacturing facilities. In one embodiment, inert gas can be used in semi-conductor manufacturing processes. Many kinds of inert gas (e.g., nitrogen gas) can be used to purge and provide an inert environment for semi-conductor wafer processing. The inert environment prevents air from contacting materials that are prone to oxidation. Nitrogen can be used to purge equipment, such as equipment used in refineries or petrochemical plants. For example, inert gas can be employed to purge fluid lines containing explosive or flammable fluids. Many kinds of fluid lines can be purged of dangerous fluids before components in the fluid system are replaced or repaired. Inert gases can also be used in other settings, such as for packaging to prevent oxidation of packed items.  
       FIG. 7  illustrates one embodiment of an inert gas generation system  210  that can provide a supply of inert gas. The system  210  can produce inert gas of suitable quality for use, for example, in drilling operations as described above. The inert gas generation system  210  preferably includes a flow source  212 , a conditioning system  214 , and an output  216  of the conditioning system  214 .  
      The flow source  212  provides an output of fluid to the conditioning system  214 . The flow source  212  can be configured to output any type of fluid having a reduced amount of oxygen and an inert portion. In the illustrated embodiment, the output of the flow source  212  is exhaust gas from a combustion process.  
      An output of the flow source  212  is connected to the conditioning system  214 . The conditioning system  214  is configured to treat and/or condition the output to achieve desired flow characteristics of the flow passing out of output  216 . For example, the conditioning system  214  can be configured to convert the output of the source  212  into a fluid with suitable pressure, purity, temperature, volumetric flow rate, and/or any other desirable characteristic depending on, for example, the end use of the output flow.  
      In one non-limiting embodiment, the inert gas generation system  210  is configured to produce a flow that comprises an inert gas. The inert gas can be a highly pure inert gas, such as Nitrogen gas. In one embodiment, the inert gas comprises mostly Nitrogen gas but can include other substances, such as Oxygen and particulates.  
      In the illustrated embodiment, the flow source  212  can comprises an air/fuel engine  220 . The air/fuel engine  220  can comprise any type of air/fuel combustion engine, including open-system combustion engines such as, but without limitation, turbine engines, as well as internal combustion engines, including, but without limitation diesel, gasoline, four-stroke, two-stroke, rotary engine, and the like.  
      In an exemplary but non-limiting embodiment, the engine  220  is a diesel engine. The engine  220  can be normally aspirated, turbo-charged, super-charged, and the like. The construction and operation of such engines are well known in the art. Thus, a further description of the construction and operation of the engine  220  is not repeated herein.  
      In an exemplary but non-limiting embodiment, the engine  220  is configured to produce an output of about 400-650 horsepower (hp). In another exemplary but non-limiting embodiment, the engine  220  is configured to produce an output of about 550 hp. Optionally, the flow source  212  can comprise a plurality of similar or different engines  220 . In one exemplary but non-limiting embodiment, the flow source  212  comprises one or more diesel engines and/or one or more gasoline engines. In another embodiment, the flow source  212  comprises a plurality of diesel engines.  
      The output from the engine  220  can contain various products of combustion. The exhaust produced by the engine  220  can include, gases, liquids, and particles. For example, the output can comprise gases such as argon, hydrogen (H 2 ), nitrogen (N 2 ), oxides of Nitrogen (NO x ), carbon oxide (e.g., carbon monoxide (CO) and carbon dioxide (CO 2 )), hydrocarbons, and/or other gases. The output can also comprise fluid such as water (H 2 O) and oil. The output can also comprise particles such as diesel particulate matter, if the engine  220  is a diesel engine. Of course, the output of the flow source  212  will have different components depending on the type of flow source  212  that is employed.  
      The engine  220  can draw in ambient air through an air intake  221  and can produce exhaust containing both inert and non-inert gas. Preferably, the volume percentage of the inert gas output from the engine  220  is generally greater than the volume percentage of the inert gas typically present in ambient air.  
      In some embodiments, the volume percentage of the inert rich gas of the exhaust fluid produced by the engine  220  is at least 5% greater than the volume percentage of inert gas typically present in ambient air. In yet another embodiment, the volume percentage of the inert rich gas of the exhaust fluid produced by the engine  220  is at least 10% greater than the volume percentage of inert gas typically present in ambient air. In some embodiments, the proportion of inert gas in the exhaust of the engine  220  can be increased by increasing the power output from the engine  220 .  
      For example, diesel engines do not have a throttle valves. Thus, when a diesel engine is operating at a power output level that is below full power, the amount of fuel burned in the engine is not sufficient to burn all of the air in the engine. Thus, fuel is burned in a “lean” mixture, i.e., non-stochiometric. Thus, the exhaust gas discharged from the engine  220  contains some oxygen. However, when the power output of a diesel engine is raised, more fuel is injected, and thus, more oxygen is “burned”, thereby reducing the oxygen content of the exhaust. Thus, a further advantage is produced where the engine  220  used is sized such that during normal operation, the engine  220  is running under an elevated power output. For example, if the engine  220  is rated at about 550 horsepower, and the engine is operated at about 225 horsepower, the engine  220  will burn a substantial portion of the oxygen in the ambient air drawn into the engine  220 . Further advantages are achieved where the engine  220  is operated at near maximum power. For example, if the engine  220  is operated at about 450 horsepower, the engine will burn nearly all of the oxygen present in the air. One of ordinary skill in the art recognizes that gasoline-burning engines operate under different air/fuel principles, and thus, the proportion of oxygen present in gasoline-powered engines does not vary substantially with power output.  
      Normally, exhaust gas produced by the engine  220  will contain less oxygen than ambient air. In one-embodiment, the exhaust gas can contains less than about 10% by volume of oxygen gas, depending on the air fuel ratio of a mixture combusted therein and operating load of the engine  220 . As noted above, as the fuel injection rate of a diesel engine is increased, more oxygen is consumed, and thus, the oxygen content of the exhaust gas is similarly decreased. Preferably, the exhaust gas from the engine  220  comprises less than about 7% by volume oxygen. In another embodiment, the exhaust gas from the engine  220  contains less than about 5% by volume of oxygen gas. In another embodiment, the exhaust gas from the engine  220  comprises less than about 3% by volume of oxygen gas.  
      The low levels of oxygen gas contained in the exhaust gas can increase the inert gas purity of the gas discharged from the conditioning system output  216  of the conditioning system  214 . Additionally, the condition system  214  can produce high purity inert gas even though the working pressure of the conditioning system  214  is very low. It is contemplated the type of engine  220  employed and the power output of the engine  220  can be varied by one of ordinary skill in the art to achieve the desired purity of the gas outputted from the engine  220 . The operating conditions of the engine can also be controlled so as to produce the desired flow characteristics (e.g., volumetric flow rate, pressure, purity, and the like).  
      An exhaust conduit  226  connects the source  212  with the conditioning system  214 . In the illustrated embodiment, the exhaust conduit  226  connects the engine  220  to a mixing plenum  228  of the conditioning system  214 . The output of the engine  220  is exhaust flow or fluid that is passed through the exhaust conduit  226  and is fed into the mixing plenum  228 .  
      Optionally, the inert gas generation system  210  can include a temperature control system  236  for controlling the temperature of the exhaust fluid before the exhaust fluid enters the mixing plenum  228 . For example, the temperature control system  236  can include a heat exchanger configured to maintain the temperature of the exhaust fluid at a desired temperature.  
      In the some embodiments, the temperature control system  236  can increase or decrease the temperature of the exhaust fluid as it flows down the exhaust conduit  226 . By removing heat from the exhaust fluid flowing through the exhaust conduit  226 , a further advantage is provided in preventing undesirable effects, such as overheating, of downstream devices. Although not illustrated, the temperature control system  236  can include temperature sensors, pressure sensors, flow meters, or the like.  
      Preferably, the mixing plenum  228  is configured and sized to receive a continuous flow of exhaust fluid from the exhaust conduit  226 . However, the mixing plenum  228  can be configured and sized to receive an intermittent flow or any type of flow of exhaust fluid. Additionally, the mixing plenum  228  can be adapted to receive the exhaust flow at various volumetric flow rates.  
      In an exemplary but non-limiting embodiment, the mixing plenum  228  includes a enlarged chamber  229 . The chamber  229  can comprise a plurality of channels or tubes that are configured to mix the exhaust fluid with one or more other gases. For example, in some embodiments, the mixing plenum  228  can include the air intake  230  that draws in ambient air surrounding the mixing plenum  228  into the channels within the mixing plenum  228 . The mixing plenum  228  can combine and mix the ambient air with the exhaust fluid to output a generally homogeneous or heterogeneous fluid to downstream sections of the conditioning system  214 . In other embodiments, the mixing chamber is substantially sealed from ambient air.  
      Optionally, the mixing plenum  228  can have a controller  232  configured to selectively determine the mixture and content of the output flow from the mixing plenum. For example, the controller  232  can include a device (e.g., a motor) configured to agitate and mix the fluids contained within mixing plenum  228 .  
      Optionally, a feedback device  240  can be configured to control the total level of inert and non-inert gases within the mixing plenum  228 . For example, the feedback device  240  can include a controller  242  for controlling the proportion of exhaust fluid from the exhaust conduit  226  to the amount of ambient air from the air intake  230  contained within the mixing plenum  228 . In some embodiments, the feedback device  240  can be configured to reduce the amount of air flowing into the air intake  230  so as to increase the purity of the downstream inert gas, described in greater detail below. The feedback device  240  can also be configured to increase the amount of ambient air flowing into the air intake  230  and into the mixing plenum  228  so as to reduce the purity of the downstream inert gas. Thus, the feedback device  240  can selectively increase and/or decrease the content and purity of the downstream fluid in the conditioning system  214 .  
      Although not illustrated, the feedback device  240  can include one or more sensors configured to detect, for example, the level of the constituents within the mixing plenum  228  and/or within the exhaust conduit  226 , the flow parameters (e.g., temperature, flow rate, pressure) of the exhaust fluid passing through the exhaust conduit  226 , and the like. The feedback device  240  can be an open or closed loop system for controlling the flow of substances passing through the conditioning system  214 .  
      For example, the feedback device  240  can be an open system that commands the temperature control system  236  wherein an operator can determine and set the temperature of the exhaust fluid fed into the mixing plenum  228 . In another embodiment, the feedback device  240  can be a closed loop system and be configured to command the temperature control system  236  to dynamically change the temperature of the fluid passing through the conditioning system  214  depending on, for example, the temperature of the fluid passing out of the conditioning system output  216 .  
      Optionally, gas analysis can be performed of the exhaust fluid from the source  212  to ensure gas compositions are within desired levels. Such an analysis can be incorporated into a process controller (not shown) integrated with the conditioning system  214 , or any other part of the system  210 . In one embodiment, the process controller is integrated with the controller  242 . However, other components of the conditioning system  214  can have one or more process controllers for determining the composition of the fluid passing through the system  214  to control the composition of the output gas passing out of the conditioning system output  216 .  
      The conditioning system  214  can also include a plenum conduit  244  that extends from the mixing plenum  228  to a compressor  246 . Thus, fluid from the mixing plenum  228  can pass through the plenum conduit  244  and into the compressor  246 .  
      In one non-limiting embodiment, the compressor  246  is configured to draw fluid from the mixing plenum  228  and increase the pressure thereof. For example, the compressor  246  can be configured to raise the pressure of the fluid from the mixing plenum  228  to pressures from about 100 psig to about 600 psig.  
      The compressor  246  can be any type of compressor. Preferably, the compressor  246  is a rotary screw type compressor. However, the compressor  246  can be a pump with fixed or variable displacement that causes an increased downstream fluid pressure. It is contemplated that one of ordinary skill in the art can determine the type of compressor to achieve the desired pressure increase of the fluid. For example, in one embodiment the compressor  246  is a booster compressor. Although not illustrated, the inert gas generation system  210  can have a plurality of compressors configured to draw fluid from the mixing plenum.  
      The compression process performed by the compressor  246  can be used to remove constituents from the exhaust fluid it receives from the plenum conduit  244 . For example, the mixing plenum  228  can feed exhaust fluid that comprises water into the plenum conduit  244 . The plenum conduit  244  then delivers the fluid to the compressor  246 . The compression process of the compressor  246  can remove an amount, preferably a significant amount, of water from the fluid. In one exemplary non-limiting embodiment, a water knock out vessel is included in the compressor  246  to collect water removed from the fluid. Additionally, a coalescent filter (not shown) can be provided to remove additional entrained water and oil carryover that may be present in the output fluid.  
      The conditioning system  214  can also include a compressor conduit  250  that extends from the compressor  246  to a filtration unit  251 .  
      The filtration unit  251  can include one or more devices to remove components from the fluid delivered by the compressor conduit  250 . In the illustrated embodiment, the filtration unit  251  includes a filtration system  252  and a particulate filter  260 . In one non-limiting exemplary embodiment, fluid delivered from the compressor  246  can pass through the compressor conduit  250  and into the filtration unit  251 .  
      Optionally, the conditioning system  214  can also include a temperature control system  256  configured to adjust the temperature of fluid passing through the compressor conduit  250 . Preferably, the temperature control system  256  is configured to lower the temperature of the fluid proceeding along the compressor conduit  250  to a desired temperature.  
      For example, the temperature control system  256  and the compressor  246  can work in combination to adjust the temperature of the fluid passing therethrough to a desired temperature to prevent, for example, overheating of downstream components (e.g., the filtration unit  251 ). In at least one embodiment, the compressor  246  can provide fluid to compressor conduit  250  at a predetermined pressure. The temperature control system  256  can be configured to increase or decrease the temperature of the fluid to adjust the pressure of the fluid. For example, the temperature control system  256  can reduce the temperature of the fluid passing through the compressor conduit  250  to reduce the pressure of the fluid delivered to the filtration unit  251 . Alternatively, the temperature control system  256  can increase the temperature of the fluid passing through the compressor conduit  250  to increase the pressure of the fluid delivered to the filtration unit  251 .  
      The temperature control system  256  can be different or similar to the temperature control system  236 . In at least one embodiment, the temperature control system  256  is a heat exchanger that can rapidly change the temperature of the fluid that passes along the compressor conduit  250 . Similar to the temperature control system  236 , the temperature control system  256  can be part of an open or closed loop system.  
      The filtration unit  251  can be configured to capture and remove undesirable substances from the exhaust fluid. The filtration unit  251  can include a filtration system  252  configured to remove undesired substances that may be present in the exhaust fluid. For example, the filtration system  252  can be configured to capture selected gas impurities. In one embodiment, the filtration system  252  can capture carbon oxides, hydrocarbons, aldehydes, nitrogen oxides (e.g., typically nitric oxide and a small fraction of nitrogen dioxide), sulfur dioxide, and/or other particulate that may be in the exhaust fluid. The filtration system  252  can comprise one or more absorption filters and/or vessels that are suitable for removing one or more undesirable substances.  
      With continued reference to  FIG. 7 , the filtration unit  251  of the conditioning system  214  can also include a filtration system conduit  254  that extends from the filtration system  252  to the particulate filter  260 . Such a particulate filter  260  can comprise of one or more absorption filters and/or vessels. The particulate filter  260  can be configured to remove particulates that may undesirably adversely affect, for example, the performance of downstream components of the conditioning system  214  or purity of the gas produced by the conditioning system  214 . If the engine  220  is a diesel engine, the particulate filter  260  is preferably a filter that captures and removes diesel particulate matter from the fluid passing therethrough. In one embodiment, the particulate filter  260  removes a substantial portion of the particulate matter from the fluid.  
      The system  210  can also include an additional heat exchanger downstream from the particulate filter  260 . The heat exchanger can be configured to adjust the temperature of the filtered fluid from the particulate filter  260 . Raising the temperature of the upstream fluid can be beneficial because such heating reduces the likelihood that any remaining water vapor will condense out and damage downstream components. Optionally, the additional heat exchanger can be provided with heat from upstream temperature control systems (e.g., temperature control systems  236 ,  256 ). For example, the temperature control system  236  can be a heat exchanger that cools the exhaust fluid produced by the engine  220 . The heat removed by the heat exchanger  236  can be delivered to the additional downstream heat exchanger. The additional heat exchanger can then use that energy to heat the filtered fluid preferably at some point downstream of the filtration unit  251 . It is contemplated that at least one of the temperature control systems can provide energy (e.g., heat) to another temperature control system or heat exchanger. One of ordinary skill in the art can determine the type, location, and configuration of one or more temperature control systems to control the temperature of the exhaust fluid as desired.  
      The system  210  can also include a particulate conduit  262  which extends from the particulate filter  260  to a separation unit  266 .  
      With reference to  FIGS. 7 and 7 A, the conditioning system  214  can also include a device adapted for separating inert substances from non-inert substances. In the illustrated embodiment, the conditioning system  214  includes the separation unit  266 . In one embodiment, the separation unit  266  is a membrane separation unit including a chamber  268  and a separation membrane  270  (shown in  FIG. 7A ) within the chamber  268 . As shown in  FIG. 7A , the membrane separation unit  266  has a membrane  270  that partitions the chamber  268  into a plurality of chambers.  
      In the illustrated embodiment, the membrane  270  divides the chamber  268  into an inert chamber  276  and a non-inert chamber  278 . Preferably, during operation of the system  210  at least a portion of the inert chamber  276  contains fluid that comprises mostly inert gas, and the non-inert chamber  278  contains mostly non-inert gas that is filtered from the exhaust fluid. Additionally, the separation unit  266  can have an inlet  280  and an outlet  281  that are located on the same side of the membrane  270 . Both the inlet  280  and the outlet  281  can be in fluid communication with the inert chamber  276 . Preferably, the inlet  280  and outlet  281  are in fluid communication with opposing portions of the inert chamber  276 .  
      The inert chamber  276  can be sized and configured to define a flow path between the inlet  280  and the outlet  281 . The non-inert chamber  278  can be sized and configured to define a flow path between the membrane  270  and the vent  294 . Preferably, the vent  294  is located on one side of the membrane  270  and both the inlet  280  and the outlet  281  are located on the other side of the membrane  270 .  
      The membrane  270  can be configured to allow certain substances to pass therethrough at a first flow rate and other substances to pass therethrough at a second flow rate different than the first flow rate. For example, such membrane separation units  266  can be provided with a membrane  270  that allows different gases to pass therethrough at different rates. The effect is that the retentate gas, i.e., gases that do not permeate through the membrane  270 , remain on the inlet side of the membrane  270  within the inert chamber  276 . These gases proceed along the chamber  276  towards, and eventually pass through, the outlet  281 . The permeate gases, preferably non-inert gas, of the fluid delivered through the inlet  280  pass through the membrane  270  and through the non-inert chamber  278  and are discharged out of the vent or outlet  294  into the atmosphere, or are further sequestered.  
      In an exemplary but non-limiting embodiment, the membrane  270  is an elongated generally planar membrane extending across the chamber  268  and is configured to allow the migration of fluid (e.g., gas) therethrough. Fluid, preferably comprising gases, enters the inert chamber  276  through the inlet  280 , some gases pass through the membrane  270  while others do not. In some membrane separation units  266 , the membrane  270  can be configured to allow non-inert gases (e.g., oxygen) to pass more readily through the membrane  270  and inert gas (e.g., nitrogen) to pass through the membrane  270  at a much lower rate. The membrane  270  can thus be used to separate fluid passing in through the inlet  280  into an inert gas flow that passes out of the outlet  281  and a non-inert gas flow that passes through the membrane  270  and out of the vent  294 .  
      In one embodiment, fluid passing through the inlet  280  and into the separation unit  266  can include, for example but without limitation, nitrogen gas, oxygen gas, oxides of carbon, oxides of nitrogen, and oxide of sulfur, as well as other trace gases. The membrane  270  can be configured to allow one or more of the non-inert gases, such as oxygen gas, to pass therethrough at a relatively higher rate than the rate at which inert gas, such as nitrogen gas, can pass therethrough. Other gases such as carbon dioxide, oxides of nitrogen, oxides of sulfur, and other trace gases may also pass at a higher rate through the membrane  270  than rate at which nitrogen gas passes through the membrane  270 . The inert gases are thus captured in the inert chamber  276  and the non-inert gases pass through the membrane  270  and into the non-inert chamber  278 . The result is that the gas remaining in the inert chamber  276  has a high concentration of inert gases. Of course, the concentration of the inert gas of in the inert chamber  276  can vary along the inert chamber  276  in the downstream direction. Preferably, the gas in the inert chamber  276  and proximate to the outlet  281  comprises substantially inert gas.  
      In the present exemplary but non-limiting embodiment, the fluid within the inert chamber  276  can be largely nitrogen gas and may include other inert gases. For example, the inert chamber  276  can contain inert gases such as, for example, without limitation, argon, carbon monoxide, and hydrocarbons. Preferably, most of the hydrocarbons have been filtered out of the exhaust fluid produced by the engine  220  by the filtration unit  251 . Optionally, the membrane  270  can be configured to allow water vapor to pass therethrough at a higher rate than the rate at which nitrogen gas can pass therethrough. Thus, the separation unit  266  can receive fluid having water, inert gases, and non-inert gases. The separation unit  266  can produce a first flow of mostly inert gas flow and a second flow of non-inert gas and water. The first flow passes through the inert chamber  276  and out of the outlet  281  and the second flow passes through the membrane  270  and then through the non-inert chamber  278  and out of the vent  294 .  
       FIG. 7B  illustrates an embodiment of a membrane that can be employed by the separation unit  266  to filter fluid. The components of the system  266  have been identified with the same reference numerals as those used to identify corresponding components of the system  210 , except that “′” has been used.  
      In one exemplary but non-limiting embodiment, the membrane  270 ′ can be a hollow fiber, semi-permeable membrane. A body  302  of the membrane  270 ′ can allow certain substances to pass therethrough at a first flow rate and other substances to pass therethrough at a second flow rate different than the first flow rate. Although not illustrated, the hollow fiber membrane  270 ′ can be disposed in the chamber  268  of the unit  266  shown in  FIG. 7A . The construction of this type of membrane separation unit is well-known in the art, and thus, a further detailed description of the system  266  is not included herein.  
      The hollow fiber membrane  270 ′ can include an inlet  300 , the body  302 , a central chamber  310 , and an outlet  304 . The hollow fiber membrane  270 ′ can separate the fluid provided by the conduit  262  ( FIG. 7 ) into a purified inert gas flow and a non-inert gas flow. In some embodiments, with reference to  FIG. 7B , fluid passing through the conduit  262  can pass into the separation unit  266  and into the inlet  300  of the membrane  270 ′ in the direction indicated by the arrow  308 . The fluid entering the membrane  270 ′ can include nitrogen gas, oxygen gas, carbon dioxide, oxides of nitrogen, and oxides of sulfur, as well as other trace gases. As the fluid flows through the central chamber  310  defined by the body  302 , the fluid is separated into its component gases migrate through the body  302 . Preferably, the membrane  270 ′ separates the fluid it receives into a first stream of mostly inert fluid that passes through the chamber  310  and out of the outlet  304  and another stream of fluid that passes through the body  302  of the membrane  270 ′ in the direction indicated by arrows  311 . That is, a stream of inert gases passes through the chamber  310  and out of the outlet  304 . The separation unit  266  then delivers those inert gases to the conduit  290  (see  FIG. 7 ). The non-inert gases which pass through the body  302  of the membrane  270 ′ can be directed to the vent  294  of the unit  266  and discharged into the atmosphere, or further sequestered.  
      Although not illustrated, the separation unit  266  can include any suitable number of membranes  270 ′. The membrane separation  266  may have an increased or reduced number of membranes  270 ′ for an increased or reduced, respectively, filtering capacity of the separation unit  266 . For example, the separation unit  266  can include thousands or millions of the hollow fiber semi-permeable membranes  270 ′ that are bundled or packed together. The separation unit  266  can therefore have an extremely large membrane surface area capable of filtering out non-inert gas from the fluid passing through the conditioning system  214 . Of course, the length of the membrane  270 ′ can be varied to achieve the desired membrane surface area and pressure drop across the separation unit  266 .  
      The separation unit  266  can receive exhaust fluid from the conduit  262  and remove at least a portion of the non-inert component of the exhaust fluid. The separation unit  266  can then output an inert rich gas. In one exemplary embodiment, the separation unit  266  can produce inert rich gas that comprises at least 96% by volume of inert gas. In one exemplary embodiment, the separation unit  266  can produce inert rich gas that comprises about 98% by volume of inert gas. In another embodiment, the inert rich gas comprises about 99% by volume of inert gas. In yet another embodiment, the inert rich gas comprises about 99.9% by volume of inert gas. Advantageously, because the separation unit  266  only has to remove a low amount of non-inert gas from the exhaust fluid provided by the conduit  262 , the separation unit  266  can produce highly pure inert rich gas at high volumetric flow rates. The separation unit  266  can therefore rapidly separate the exhaust flow into non-inert rich gas and an inert rich flow. In one embodiment, the separation unit  266  removes less than about 10% by volume of the fluid and discharges highly pure inert rich gas.  
      Optionally, the conditioning system  214  can comprise a plurality of separation units  266 . Each of separation units  266  can include one or more membranes  270 ′, or membrane  270 . Thus, each of the membrane separation units  266  can comprise one or more similar or dissimilar membranes. It is contemplated that a plurality of separation units  266  of the conditioning system  214  can be in a parallel configuration or in a series configuration. For example, a plurality of membrane separation units  266  can be in series along the conditioning system  214  to provide an extremely pure inert fluid, preferably a gas, out of the conditioning system output  216 . Each of the separation units  266  can increase the purity of the inert gas passing through the conditioning system  214 .  
      In one exemplary but non-limiting embodiment of  FIG. 7C , the separation unit  266  is a pressure swing adsorption system (PSA) that preferably produces a purified inert gas. The PSA  266  may comprise a plurality of beds for producing inert rich gas. Preferably, each of the beds includes an adsorption material (e.g., carbon molecular sieve or silica gel) adapted to adsorb a non-inert component at a faster rate than the rate of absorption of inert components. In one non-limiting embodiment, the PSA  266  includes a pair of beds  360 ,  362  and each bed  360 ,  362  can have adsorption material adapted to adsorb oxygen at a higher rate than its rate of absorption of nitrogen. Thus, oxygen is quickly trapped by the beds  360 ,  362  and nitrogen can pass, preferably easily, through each of the beds. The pressure upstream of the PSA  266  can be increase or decrease to increase or decrease, respectively, the flow rate at which gases pass through the beds  360 ,  362 . Additionally, the proportion of the inert gas to the non-inert gas produced by the PSA  266  can be increased or decreased by decreasing or increasing, respectively, the upstream pressure.  
      During a first production cycle, the valves  359 ,  361 ,  363  are closed and the fluid from the conduit  262  flows through the conduits  364 ,  366  and into the bed  360 . The adsorption material in the bed  360  captures the non-inert substances in the fluid flow and allows fluid comprising a high proportion of inert substances (e.g., nitrogen gas) to non-inert substances to pass therethrough. The inert substance, preferably inert fluid (e.g., an inert rich gas), then passes out of the bed  360  and into the conduits  368 ,  324 . The conduit  324  can then deliver the inert rich gas to the conduit  290  ( FIG. 7 ).  
      While fluid flows through the bed  360 , the bed  362  can optionally undergo depressurization and can be purged by, for example, nitrogen rich fluid to remove non-inert substances, such as oxygen, that has accumulated in the bed  362 . The filtering capacity of the bed  362  is thus increased due to the removal of substances from the bed. For example, the valves  369 ,  371  can be closed so that fluid provided by the bed  360  pass through the conduits  368 ,  373 ,  374  and into the bed  362  to purge the bed  362 . The purge fluid can pass out of the bed  362  and into the conduits  375 ,  376 . The purge fluid preferably comprises substantial amounts of non-inert gas such as oxygen and other trace gases. Although not illustrated, the separation system  266  can have a purge container that contains a fluid that can be used to purge the beds  360 ,  362 .  
      During a second cycle, the valves  363 ,  377  are opened and the valves  383 ,  385  are closed. Fluid from the conduit  262  passes through the conduit  379  and into the conduit  375  and through the bed  362 . The bed  362  can capture non-inert components of the fluid and permit inert components to flow into the conduits  374 ,  324 . While the fluid flows through the bed  362 , the bed  360  can optionally undergo depressurization and can be purged by some, for example, nitrogen rich fluid to remove oxygen that has accumulated in the bed  360 . For example, the valves  371 ,  369  can be closed and the valve  370  can be opened so that fluid from the bed  362  passes through the conduits  374 ,  373 ,  368  to purge the bed  360 . Of course, the purge cycle can be performed periodically during a production cycle.  
      In the illustrated embodiment, the first cycle can be performed until the bed  360  has reached a predetermined saturation level. For example, the first cycle can be performed until the bed  360  is generally completely saturated. After the bed  360  is saturated, the bed  360  can be purged so that the non-inert substances captured by the bed  360  are discharged. After the first cycle, the second cycle can be performed until the bed  362  likewise reaches a predetermined saturation level. The bed  362  and be subsequently purged to remove non-inert substances from the bed  362 . These acts can be repeated to produce highly purified inert rich gas.  
      Optionally, the conditioning system  214  ( FIG. 7 ) can also include a purity control system  320  for controlling the purity of the fluid passing out of the conditioning system output  216 . The purity control system  320  can selectively determine the purity of the fluid passing to the conditioning system output  216 . In one embodiment, the purity control system  320  can comprise one or more valves for restricting the flow of fluid from the separation unit  266  and may have one or more sensors for measuring the contents of the fluid flow produced by the separation unit  266 .  
      In an exemplary but non-limiting embodiment, the purity control system  320  includes a valve  322  for restricting the flow of fluid from the separation unit  266 , preferably a membrane separation unit. When the inert gas concentration from the separation unit  266  is below a predetermined amount, the valve  322  can selectively restrict the flow through the conduit  324  so as to raise the pressure in the membrane separation unit  266 . In the illustrated embodiment of  FIGS. 7 and 7 A, when the valve  322  inhibits the flow through the conduit  324  which extends from the conduit  290  to a compressor  330 , the pressure within the inert chamber  276  is increased. By raising the pressure in the inert chamber  276 , the volumetric flow rate of gas passing through the membrane  270  and into the non-inert chamber  278  is increased. Thus, because a greater amount of permeate gas passes through the membrane, there is increased concentration of the inert gas discharged from the membrane separation unit  266 . Of course, the reduced upstream pressure may reduce the volumetric flow rate of the fluid passing out the output  216 .  
      When the separation unit  266  produces an inert gas concentration above a predetermined amount, the valve  322  can be opened so as to increase the flow rate of fluid through the conduit  324 . By opening the valve  322 , the upstream pressure can be reduced in the conditioning system  214  while providing an increased output from the output  216 . For example, by reducing the pressure in the separation unit  266  having a membrane, the volumetric flow rate of gas passing from the inert chamber  276  through the membrane  270  ( FIG. 7A ) and into the non-inert chamber  278  may be reduced. Thus, a reduced amount of permeate gas may pass through the membrane. In this manner, the proportion of the inert gas to non-inert gas of the fluid discharged from the separation unit  266  into the conduit  290  may be reduced. Thus, the valve  322  can be operated to determine the volumetric flow rate and/or the purity of the fluid outputted from the conditioning system  214 . One of ordinary skill in the art can determined the desired purity of the gas flowing from the conditioning system  214  and the desired volumetric flow rate based on the use of the gas.  
      With reference to  FIG. 7 , the purity control system  320  can also include an inert gas sensor  334  that is configured to detect flow parameters (e.g., the concentration of inert gases of the fluid, the amount of fluid emanating from the separation unit  266 , and the like). The measurements from the inert gas sensor  334  can be used to adjust the amount of fluid that flows through the conduit  324  by operating the valve  322 . It is contemplated that the purity control system  320  can be an open or closed loop system.  
      Optionally, the conditioning system  214  can also include the compressor  330  (e.g., a booster pump) that can be used to raise the pressure of the gas discharged from the separation unit  266  to a desired pressure. In some embodiments, the booster compressor  330  can be configured to raise the pressure of gas to about 1000 psig. In one embodiment, the booster compressor  330  can increase the pressure of the inert rich gas about 200 psig to about 4000 psig. For example, the booster compressor  330  can increase the pressure of the exhaust fluid to about 1000 psig to about 2000 psig. However, the booster compressor  330  can increase the pressure to any suitable pressure depending on the use of the inert rich gas. Inert gas from the booster compressor  330  can be passed through a conduit  344  and out of the conditioning system output  216  to the upper portion  348  of a drill stem arrangement  18 , as illustrated in  FIG. 1 . The gas can continue to flow until it reaches the drill stem assembly  20  as described above. Thus, the compressor  330  can be selectively configured to raise the pressure of the gas to various pressure levels depending on the desired flow characteristic of the gas passing through the drill stem arrangement  18 .  
      The engine  220  can be selected and configured to provide sufficient flow of exhaust fluid for generating the desired amount of inert gas outputted from the conditioning system  214  for any of the uses of inert gas described herein. That is, the engine  220  can be selected to output different levels of purity and different gas flow rates. Additionally, the operating speed of the engine  220  can be controlled to further ensure that the desired amount of exhaust fluid is delivered to the condition system  214 . The conditioning system  214  is preferably configured to produce and deliver generally highly pure inert gas which is then, in turn, used by, for example but without limitation, a drilling operation. It is contemplated that various components can be removed from or added to the conditioning system  214  to achieved the desired flow characteristics of the output fluid flow. For example, the compressor  246  and the booster compressor  330  can be configured so that the conditioning system output  216  discharges inert fluid at a sufficient pressure and volumetric flow rate for any of the uses disclosed herein. Additionally, the filtration system  252  and the particulate filter  260  can be configured to remove any undesirable substance in the exhaust fluid produced by the engine  220 . Optionally, one or more components of the conditioning system  214  can be removed, or not used during a production cycle. For example, during an operation cycle, the filtration system  252  and the particulate filter  260  can be off-line if some substances do not need to be filtered out of the exhaust fluid. In another operation cycle, the filtration system  252  and the particulate filter  260  can be online such that the inert gas generating system  210  provides an extremely pure inert gas from the conditioning system output  216 .  
      In an exemplary but non-limiting embodiment, the conditioning system  214  may have a bypass system  350  for controlling the mixture of the fluid flow flowing out of the conditioning system output  216 . For example, the bypass system  350  can include a bypass system conduit  352  which extends from a location upstream from the unit  266  to a location of the conditioning system  214  downstream from the unit  266 . In the illustrated embodiment, the bypass system conduit  352  extends from the particulate conduit  262  to the conduit  344 . However, the bypass system conduit  352  can extend from any point along the conditioning system  214  upstream from the separation unit  266  to any point of the conditioning system  244  downstream from the separation unit  266 .  
      In the illustrated embodiment, the flow passing through the conduit  262  can be separated into a first flow flowing into the separation unit  266  and a second flow flowing into the bypass system conduit  352 . An amount of the first flow can pass through the separation unit  266  and through the conduits  290 ,  324 , compressor  330 , and the conduit  344 . Of course, the separation unit  266  can filter out non-inert portions of the first flow. The concentrated inert gas flow produced by the separation unit  266  can be combined with the second gas flow passing through the conduit  352  at the junction of the conduits  352 ,  344 . Thus, when the concentration of inert gas produced by the conditioning system  214  is below a predetermined amount, the bypass system  350  can reduce, or stop, the flow of fluid through the conduit  352 . By reducing the flow of the fluid through the conduit  352 , the purity of gas discharged from the conditioning system output  216  can be increased.  
      Alternatively, when the concentration of inert gas produced by the conditioning system  214  is above a predetermined amount, the bypass system  350  can increase the amount of fluid flowing through the conduit  352  and which is then combined with the inert fluid flow produced by the separation unit  266 . In this manner, the concentration of inert gas outputted from the conditioning system output  216  can be reduced. The bypass system  350  can therefore be operated to selectively control and determine the purity of the inert gas produced and delivered out of the conditioning system  214 . Optionally, of course, the operating speed of the engine  220  can be varied to control the purity and the amount of gas discharged from the conditioning system.  
      Optionally, the bypass system  350  can include a valve  354  that can be used to selectively control the flow rate of the fluid passing through the conduit  352 . Those skilled in the art recognize that the valves of the conditioning system  214  may be manually or automatically controlled and may comprise sensors.  
      Optionally, a further advantage can be achieved wherein one or more of the components of the conditioning system  214  can be powered by the engine  220 . This provides the advantage that the source of the exhaust fluid can also be used to provide power to various components of the conditioning system  214 . Preferably, engine  220  can provide sufficient power to operate one or more of the components of the conditioning system  214 . Thus, those components may not require any additional power from another power source.  
      In some embodiments, engine  220  can produce exhaust fluid and a another secondary output, such electrical power. For example, the engine  220  can be a generation system (e.g., a generator) that generates power in the form of electricity. The electricity can be passed through an electrical line  348  and can be delivered to a motor of the compressor  246 . The electricity generated from the engine  220  can therefore be used to power the compressor  246 . The engine  220  advantageously provides exhaust fluid that can be treated by the conditioning system  214  to produce a highly pure inert gas and can be used to power the compressor  246 . It is contemplated that one of ordinary skill in the art can determine the appropriate sized engine  220  to provide the desired power suitable for driving one or more of the components, such as compressor  246 .  
      Although not illustrated, the engine  220  can be in communication with other components of the conditioning system  214 . For example, the engine  220  can be in communication with the booster  330 . An electric power line can provide electrical communication between the engine  220  and the booster  330 . Additionally, the engine  220  can provide power to the compressor  246  and the booster  330  simultaneously, or independently.  
      Optionally, the engine  220  can be in communication with one or more of the temperature control systems of the conditioning system  214 . For example, the engine  220  can provide power in the form of electricity to a temperature control system that can increase the temperature of the fluid passing through the conditioning system  214 . Optionally, the valves  322  and  354  may be automatic valves that are also powered by the engine  220 . The valve  322 ,  354  can comprise controllers and other sensor devices that can optionally be powered by the engine  220 .  
      The engine  220  can be in communication with one or more of the feedback devices of the conditioning system  214 . Although not illustrated, the engine  220  can have a communication line connected, for example but without limitation, to the feedback device  240  and also the inert gas sensor  334 . The feedback devices may selectively control the operating speed of the engine  220 . For example, if the exhaust fluid flow reaches a predetermined volumetric flow rate, a feedback device may reduce the engine&#39;s operating speed. Additionally, the operating speed of the engine  220  may be selectively controlled to determine the amount of power produce by the engine  220 . In one embodiment, the operating speed of the engine  220  can be increased or decreased to increase or decrease, respectively, the amount of electricity produced by the engine  220 .  
      Optionally, a further advantage can be achieved where the engine  220  can provide mechanical power to one or more components of the conditioning system  214 . In an exemplary but non-limiting embodiment, the engine  220  has a mechanical output system  351  in the form of an output shaft  352  that can be connected to one or more of the components of the conditioning system  214 . For example, the output shaft  352  in the illustrated embodiment is connected to the mixing plenum  228 . As the engine  220  operates, the output shaft  352  rotates. The rotation of the output shaft  352  can be used to agitate the fluid contained in the mixing plenum  228 . In one embodiment, the rotational movement of the output shaft  352  is translated into linear movement of at least one plenum within the mixing plenum  228 . The movement of the plenum can agitate fluid comprising the exhaust fluid and the air drawn through the air intake  230 . Although not illustrated, a further advantage is achieved where the output shaft  352  is connected to the compressor  246  to as to drive the compressor  246 . In the system  10 , the compressor  246  can require substantial power to compress the gases flowing therethrough. Thus, by driving the compressor with a shaft from the engine  220 , the compressor  246  can be driven more efficiently. For example, a direct shaft drive connection between the engine  220  and the compressor  246  avoids the losses generated by converting shaft power from the engine  220  into electricity, then back to shaft power with an electric motor at the compressor  246 . Further, the entire system  210  can be made lighter and more easily portable. For example, a mechanical connection between the engine  220  and the compressor  246  can eliminate the need for an electric motor for driving the compressor  246 .  
      Optionally, a further advantage can be achieved where at least one or more devices of the drilling operation uses inert gas and/or power produced by the engine  220 . For example, various components of the drill stem arrangement  18  ( FIG. 1 ) can use inert rich gas produced by the conditioning system  214  and can be operated by power generated by the engine  220 . Many devices, such as lights, fans, blowers, venting systems, and/or other electrical devices, can receive power generated by the engine  220 . For example, in one limiting embodiment, the engine  220  generates power that operates the compressor  246 , the booster  330 , lights proximate to the generation system  210 , a fan which blows across the inert gas generating system  210 , and/or a plurality of lights that illuminate the area surrounding the drilling operation.  
      The engine  220  can also provide power to a battery or storage device. For example, the engine  220  can operate and can deliver power in the form of electricity to a battery which, in turn, stores the power. The battery can then deliver power to one or more components of the conditioning system  214  or the drilling operation.  
      In operation generally, the engine  220  can be operated to generate exhaust fluid. The exhaust fluid can pass through the exhaust conduit  226  and into the mixing plenum  228 . The exhaust fluid can be discharged from the mixing plenum  228  and through the plenum conduit  244  and into the compressor  246 . The compressor  246  can increase the pressure of the exhaust gas and deliver the exhaust gas through the conduit  250  to the filtration unit  251 . The filtration unit  251  can remove various substances from the exhaust fluid, which is then passed through the separation unit  266 . The separation unit  266  can receive fluid having a first concentration of inert gas and output a fluid having a second concentration of inert gas higher than the first concentration. The inert gas can then be passed through the conduits  290 ,  324  and into the booster compressor  330 . The booster compressor  330  can increase the pressure of the fluid and discharged the fluid to the conduit  344  which, in turn, delivers the fluid out of the output  216 .  
       FIG. 8  illustrates a modified generation system and is identified generally by the reference numeral  210 ′. The components of the system  210 ′ have been identified with the same reference numerals as those used to identify corresponding components of the system  210 , except that “′” has been used. Thus, the descriptions of those components are not repeated herein.  
      In the illustrated embodiment, the conduit  226 ′ extends from the engine  220 ′ to a filtration unit, such as a catalytic converter  400 . The catalytic converter  400  can remove many of the components of the exhaust fluid passing through the conduit  226 ′. In an exemplary but non-limiting embodiment, the catalytic converter  400  can be configured to remove non-inert components of the exhaust fluid, such as carbon monoxide, hydrocarbons, volatile organic compounds, and/or nitrogen oxides (nitrogen oxide or nitrogen dioxide) to increase the purity of the inert gas of the exhaust fluid.  
      In an exemplary but non-limiting embodiment, the catalytic converter  400  of the conditioning system  214 ′ comprises a reduction catalyst and oxidation catalyst that operate to take non-inert components out of the exhaust fluid. It is contemplated that the catalytic converter can be an oxidation or three way type catalytic converter depending on the desired removal of the non-inert components of the exhaust fluid. The construction and operation of such catalytic converter is well known in the art and thus further description of the construction and operation is not repeated herein.  
      A catalytic converter conduit  406  extends between the catalytic converter  400  and a fluid separation unit  408 . Preferably, the fluid separation unit  408  includes a high temperature membrane configured to remove the water from the exhaust fluid passing therethrough.  
      For example, the engine  220 ′ can output exhaust fluid comprising various gases and a liquid, such as water. The fluid separation unit  408  can remove the water from the exhaust fluid as the fluid passes through the unit  408 . In one embodiment, the fluid separation unit  408  has a membrane (not shown) that is configured to allow gases to pass therethrough without permitting the passage of water. In other words, the gas component of the exhaust fluid can flow into and out of the fluid separation unit  408  and into the conduit  412 . The membrane of the fluid separation unit  408  can remove water from the exhaust fluid and deliver it to a water knock out vessel in the unit  408 . The water knock out vessel can be periodically removed from the unit  408  and emptied. Additionally, a coalescing filter (not shown) can be provided to remove oil carryover that may be present in the exhaust fluid.  
      Optionally, the fluid separation unit  408  can have a heat exchanger to increase the temperature of the fluid delivered by the conduit  406 . The heat exchanger can increase the temperature of the liquid component of the exhaust fluid for easy removal of the liquid.  
      The conditioning system  214 ′ can also include a temperature control system  416  that is connected to the fluid separation conduit  412 . The temperature control system  416  can be configured to increase or reduce the temperature of the exhaust fluid fed from the fluid separation conduit  412 . Because the fluid separation unit  408  may have features, such as a heat exchanger, to raise the temperature of the exhaust fluid, the temperature control system  416  can be configured to reduce the temperature of the exhaust fluid to desirable temperatures for feeding the exhaust through the temperature control system conduit  420  and into the compressor  246 ′.  
      The conditioning system  214 ′ can have a compressor  246 ′ which raises the pressure of the exhaust fluid. The compressor  246 ′ then delivers the fluid to a compressor conduit  250 ′, which, in turn, feeds the exhaust fluid to a filtration unit  424 . That filtration unit  424  can be configured to capture and remove undesired substances that may be present in the exhaust fluid. The filtration unit  424  can be can similar or different than the filtration unit  251 .  
      The exhaust fluid from the filtration system  424  can pass through the conduit  262 ′ and into the separation unit  266 ′. The separation unit  266 ′ can be similar or different that the units illustrated in  FIGS. 7A, 7B , and  7 C. The separation unit  266 ′ can receive exhaust fluid and can remove at least a portion of the non-inert component of the exhaust fluid and pass inert rich gas into the conduit  324 ′. The inert fluid can then be fed into the booster pump  330 ′. The booster pump  330 ′ can increase or decrease the pressure of the fluid and can pass the fluid into the conduit  344 ′ and out of the conduit system output  216 ′.  
      The engine  220 ′, of course, can generate and provide power to one or more components of the conditioning system  214 ′. For example, the engine  220 ′ can be in electrical communication with at least one of the compressors  246 ′,  330 ′. The engine  220 ′ can therefore power one or more of the compressors which can provide a pressure increase in the conditioning system  214 . Optionally, the engine  220 ′ can provide power to any other type of power consumption device.  
      Optionally, a further advantage can be achieved where the inert gas generation systems  210 ,  210 ′ can be arranged in one or plurality of containers. For example, but without limitation, the systems  210 ,  210 ′ can be assembled into a single ISO container or broken down into simple parts and assembled into a plurality of ISO or other containers. An ISO container containing parts or complete inert gas generation system  210 , or  210 ′, can be conveniently transported to various locations.  
      The various methods and techniques described above provide a number of ways to carry out the disclosed embodiments. Of course, it is to be understood that not necessarily all objectives or advantages described may be achieved in accordance with any particular embodiment described herein. Thus, for example, those skilled in the art will recognize that the methods may be preformed in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages as may be taught or suggested herein.  
      Furthermore, the skilled artisan will recognize the interchangeability of various features from different embodiments disclosed herein. Similarly, the various features and steps discussed above, as well as other known equivalents for each such feature or step, can be mixed and matched by one of ordinary skill in this art to perform methods in accordance with principles described herein. Additionally, the methods which is described and illustrated herein is not limited to the exact sequence of acts described, nor is it necessarily limited to the practice of all of the acts set forth. Other sequences of events or acts, or less than all of the events, or simultaneous occurrence of the events, may be utilized in practicing the embodiments of the invention.  
      Although the inventions have been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the inventions extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof. Accordingly, the inventions are not intended to be limited by the specific disclosures of preferred embodiments herein.