Method and apparatus for the destruction of volatile organic compounds

0001This application is a division of application Ser. No. 08/538,692, filed Oct. 3, 1995, now U.S. Pat. No. 5,592,811.

TECHNICAL FIELD

0002This invention relates generally to a method and apparatus for the destruction of hazardous materials, such as volatile organic compounds, and more particularly, to the destruction of volatile organic compounds through the use of a turbine engine in order to produce power.

BACKGROUND OF THE INVENTION

0003Increasingly over the past half century, air quality has become an issue of public concern. Over this period, the scientific community has steadily improved its understanding of the origins of the air pollution that is apparent over most major U.S. cities. A large part of this air pollution is attributable to the release of volatile organic compounds into the atmosphere. As a result, the reduction of the releases of volatile organic compounds has become an increasingly important part of the overall strategy to improve air quality.

0004The most familiar volatile compound reduction technique is the control of fuel vaporization by vapor recovery techniques, first on automobiles and now on gasoline stations located in nonobtainment areas. As a result, the steady year over year increase in U.S. releases of these compounds has leveled off and is now even declining.

0005Manufacturing sites are responsible for approximately 8.5 million tons of volatile organic compound emissions annually. Solvent vaporization or in some cases, hydrocarbon byproducts, are key to the manufacturing process of many of the items used regularly in daily life. The manufacture of familiar consumer products results in the release into the atmosphere of significant amounts of organic compounds such as pentane, ethanol, methanol, ethyl acetate, and many others. The control of volatile organic compounds is essential to the environmentally friendly manufacture of these products, and thus, there remains a struggle with the cost of control versus the loss of competitiveness.

0006The most common control method in use today is the thermal oxidizer. In connection with this method, the volatile solvent is released in amounts generally less than a few thousand parts per million into the plant air system. This air is then selectively collected and fed into a combustion chamber where it is mixed with enough natural gas to sustain combustion. It is then ignited in a large chamber that incinerates the volatile solvent, as well as, the natural gas, thereby producing carbon dioxide and water vapor as the primary products of combustion. These oxidizers are large, complicated devices that represent a major capital expense and require significant amounts of electricity and gas to operate. While heat can sometimes be recovered, generally speaking, thermal oxidizers represent a significant economic loss to the businesses using them. In a typical U.S. industrial plant, the cost of operating this type of device easily adds 25%, and often much more, to the yearly energy bill.

0007Another current control technology uses solvent recovery methods that pass the air from the plant through an activated charcoal filter. Periodically, the charcoal is heated, driving off highly concentrated volatile compounds into a chilled condensing system. The output is a liquid organic compound often requiring hazardous waste treatment. The cost of operation, as well as the initial capital costs, are significantly higher than the thermal oxidizer, thereby making this control technology less attractive for the majority of industrial sites.

0008Accordingly, an efficient and cost effective device for the destruction of volatile organic compounds is needed.

SUMMARY OF THE INVENTION

0009A system for the destruction of volatile organic compounds according to the present invention addresses the shortcomings of the prior art.

0010In accordance with one aspect of the present invention, a system for the destruction of volatile organic compounds comprises a power generator, such as a gas turbine engine, which is provided with a reaction chamber driven by a combustion device. The system further comprises a primary inlet to the combustor for supplying a primary fuel. A secondary fuel is also supplied to the combustor and to the reaction chamber. The secondary fuel comprises air and an amount of a volatile organic compound. The system further includes a compressor, typically the compressor of the power generator, for compressing the secondary fuel. The reaction chamber is preferably connected to an exit of the combustor to allow for stoichiometric reaction of the two fuels after they are mixed together.

0011In accordance with a further aspect of the present invention, the power generator drives a recovery system that generates electricity.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

0012The present invention will hereinafter be described in conjunction with the appended drawing figures, wherein like designations denote like elements, and:

0013<figref idref="DRAWINGS">FIG. 1</figref> is a simplified schematic drawing of a destruction device in accordance with the present invention;

0014<figref idref="DRAWINGS">FIG. 2</figref> is a schematic drawing of a device of the type shown in <figref idref="DRAWINGS">FIG. 1</figref> as utilized in an exemplary plant layout;

0015<figref idref="DRAWINGS">FIG. 3</figref> is a cross-sectional view of a combustor used in connection with the destruction device of <figref idref="DRAWINGS">FIG. 2</figref>;

0016<figref idref="DRAWINGS">FIG. 4</figref> is a partial cross-sectional view of the combustion device and reaction chamber of the destruction device of <figref idref="DRAWINGS">FIG. 2</figref>;

0017<figref idref="DRAWINGS">FIG. 5</figref> is a cross-sectional view of the compressor of the destruction device of FIG. <b>2</b>;

0018<figref idref="DRAWINGS">FIG. 6</figref> is a schematic drawing of an alternative plant layout of a destruction device in accordance with the present invention; and

0019<figref idref="DRAWINGS">FIG. 7</figref> is a further alternative embodiment of a mobile layout of a destruction device in accordance with the present invention.

0020<figref idref="DRAWINGS">FIG. 8</figref> is schematic drawing of a two stage compressor of the destruction device of <figref idref="DRAWINGS">FIG. 2.</figref>

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

0021While the way in which the present invention addresses the various disadvantages of the prior art designs will be discussed in greater detail hereinbelow, in general, the present invention provides a volatile organic compound (VOC) destruction device which includes a power generator such that the effective elimination of VOC's also results in the co-generation of power. The power so produced can be converted into electricity, which can in part drive the destruction device as well as produce power for other uses.

0022With reference to <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, a VOC destruction device <b>10</b>, in accordance with a preferred embodiment of the present invention, suitably includes a power generator <b>12</b> which is driven by a fuel system <b>14</b>. Fuel system <b>14</b> preferably comprises a combustor <b>16</b> and a reaction chamber <b>18</b>. As will be discussed in greater detail hereinbelow, in operation, VOC destruction device <b>10</b> utilizes natural gas or any other suitable fuel as a primary fuel supply in a conventional manner. However, in accordance with the present invention, this primary fuel is suitably mixed with a secondary fuel comprising air and preferably VOCs. This fuel mixture of primary and secondary fuels is consumed by power generator <b>12</b>.

0023In accordance with a preferred embodiment of the present invention, power generator <b>12</b> preferably comprises a gas turbine engine, for example an AlliedSignal IE-831 engine, which is produced by AlliedSignal Aerospace, Phoenix, Ariz. has been found to be suitable. However, it should be recognized that any suitable engine can be used in the context of device <b>10</b>, provided such engine can be suitably employed in the generation of power.

0024With continued reference to <figref idref="DRAWINGS">FIG. 2</figref>, power generator (engine) <b>12</b> is preferably of a conventional design. For example, engine <b>12</b> suitably includes, in spaced relation, a generator <b>20</b>, a gearbox <b>22</b>, a compressor <b>24</b> and a turbine <b>26</b>. Turbine <b>26</b>, also preferably of a conventional design, suitably includes a power turbine (not shown) connected to shaft <b>28</b>. As will be appreciated, shaft <b>28</b> is suitably connected to generator <b>20</b>, gearbox <b>22</b> and compressor <b>24</b>.

0025In accordance with the present invention, VOC destruction device <b>10</b> can be utilized to concurrently destroy VOC's and realize the fuel value of such VOC's produced from a variety of different environments. In this context, the term “VOC” is used broadly to refer to carbon containing compounds, such as hydrocarbons, dioxins, alcohols, ketinesaldehydes, ethers, organic acids, halogenareated forms of the foregoing and the like. For example, as used herein, the term VOC may refer to pentane, n-ethylmorphilin, toluene, ethanol, methanol, decabromodiphenyloxide, ethyl acetate, benzene, polystyrene and the like. Such VOC's or similar chemical compounds are typically produced from the evaporation of chemicals used in and generated by basic industrial processes to produce plastics, pharmaceuticals, bakery products, printed products and the like. A particularly preferred application of the present invention is in the area of control VOC's produced during the production of expandable polystyrene (i.e. the process to make “styrofoam”) where the primary emission is the VOC pentane.

0026Device <b>10</b> can be employed to destroy VOC's which can be collected from the plant as whole, from special isolated or hooded areas, from dryers or from a VOC concentrator utilized in such plants. In the context of the present invention, air from one or more of these environments or areas is referred to as “VOC laden air”. It should be appreciated that the amount of VOC present in such air may vary from small amounts or none to larger amounts, over time and as conditions in the plant change. As with typical prior art methods of destroying VOCs or such, the present invention may be employed even over periods of time when the VOC level is small or nonexistent. As such, the term VOC laden air includes air that from time to time may not include a significant quantity (or any amount) of a VOC.

0027VOC laden air, such as air laden with pentane resulting from the manufacture of expandable polystyrene, is first collected and thereafter suitably passed into device <b>10</b>. While such VOC laden air may be collected in any conventional manner for use in connection with the present invention, preferably, in such a process, the VOC laden air is ducted from the plant via one or more air ducts. These ducts are directly or indirectly connected to an inlet duct <b>40</b> (see <figref idref="DRAWINGS">FIG. 1</figref>) which provides VOC laden air to destruction device <b>10</b>.

0028In accordance with a preferred aspect of the present invention, power generator <b>12</b> draws in such VOC laden air together with fuel, the combustion gases of both which flow at high velocity into turbine <b>26</b> and thereby drive turbine <b>26</b>. As previously briefly mentioned, the primary fuel utilized as the power source in accordance with the present invention may comprise natural gas; alternatively, diesel oil, jet fuel, methane or any other fuel material may be utilized in an amount sufficient to sustain combustion in combustor <b>16</b>.

0029The secondary fuel comprising the VOC laden air is generally much leaner than the primary fuel. Generally speaking, the secondary fuel has a VOC concentration in the range of 0% to 1%. This 1% maximum corresponds to approximately 10,000 parts per million, depending on the type of organic compound involved. Typically this will comply with OSHA regulations as the maximum concentration allowed within plant air in order to prevent the possibility of an explosion within the plant, and in the event permissible limits are exceeded, the concentration can be reduced. However, it should be appreciated that system <b>10</b> is capable of handling higher VOC concentrations, as may be desirable in some applications.

0030With reference to <figref idref="DRAWINGS">FIG. 1</figref>, a simplified schematic view of destruction device <b>10</b> is shown. As shown, VOC laden air from inlet duct <b>40</b> is suitably directed to power generator <b>12</b>, and in particular, compressor <b>24</b> thereof. Preferably, the temperature of the inlet air A, i.e. the VOC laden air, is at a temperature of less that about 130° F. To this end, a temperature control system <b>42</b> is suitably positioned to measure the temperature of the inlet air and in the event the temperature exceeds about 130° F., the air is cooled through a cooling system <b>44</b>. As will be appreciated by those skilled in the art, cooling system <b>44</b> may suitably comprise an air or water heat exchanger suitably configured to cool the temperature of inlet air to a temperature in the range of about 59° to about 130° F.

0031Once the temperature of inlet air A is within a suitable range, such inlet air A is passed through a control valve <b>46</b> which is suitably provided with a VOC monitor <b>48</b>. As will be discussed in greater detail below, monitor <b>48</b> measures the level of VOC within inlet air A. This VOC level measurement, as will be described in greater detail below, is utilized to adjust, as appropriate, the ratio of primary and secondary fuels which are fed into combustor <b>16</b>. Regulator <b>46</b> suitably regulates the flow of air which is drawn into compressor <b>24</b>.

0032When device <b>10</b> is placed in initial operation, generator <b>20</b> is utilized to initially drive compressor <b>24</b> (as well as turbine <b>26</b>) to suitably draw inlet air A into compressor <b>24</b>. As operation of device <b>10</b> continues, the power drawn from generator <b>20</b>, through gearbox <b>22</b>, may be suitably decreased and thereafter compressor <b>24</b> is, at least in part, and preferably entirely driven by the power generated through operation of device <b>10</b>, and in particular, through the generation of energy effected by turbine <b>26</b>.

0033As discussed briefly above, compressor <b>24</b> suitably comprises the compressor of power generator <b>12</b>. With momentary reference to FIG. <b>5</b><b>8</b>, compressor <b>24</b> preferably comprises alternate respective sets of rotating blades <b>56</b> and stationary blades <b>58</b> . Rotating blades <b>56</b> are suitably rotated through rotation of shaft <b>28</b>, which is briefly noted above, is initially activated by generator <b>20</b>. In accordance with a preferred aspect of the present invention, compressor <b>24</b> comprises a multi-stage compressor, more preferably a two stage compressor, i.e. there are at least 2 rotating blades (impellers) <b>56</b> within the body of compressor <b>24</b> .

0034As will be recognized by those skilled in the art, inlet air A drawn into compressor <b>24</b> is suitably compressed to pressures ranges from about 4 to about 30 atmospheres, and preferably to about 9 atmosphere. This compression raises the temperature of inlet air A, and thus the secondary fuel, to ideally about 600° F., but suitably within the range of about 550° F. to about 650° F. The compressed air B then exits compressor <b>24</b> through outlets <b>57</b>A, <b>57</b>B and preferably enters reaction chamber <b>18</b> through inlets <b>59</b>A, <b>59</b>B.

0035With continued reference to <figref idref="DRAWINGS">FIG. 1</figref>, compressed air B is suitably directed to a flow valve <b>50</b> which is provided with a monitor <b>52</b>. Valve <b>50</b> suitably controls the amount of compressed air B which is provided to reaction chamber <b>18</b> and combustor <b>16</b>.

0036As shown best in <figref idref="DRAWINGS">FIG. 1</figref>, a primary fuel inlet <b>70</b> provides primary fuel C to combustor <b>16</b> through a flow valve <b>72</b>. Flow valve <b>72</b> preferably includes a monitor <b>74</b> to monitor the volume of fuel which is provided to combustor <b>16</b>. As will be described in greater detail hereinbelow, fuel C and a limited amount of compressed air B (including the secondary VOC fuel) is suitably provided to combustor <b>16</b>, the remaining portion of the secondary fuel being provided to reaction chamber <b>18</b>. In accordance with a particularly preferred aspect of the present invention, the combination of combustor <b>16</b> and reaction chamber <b>18</b> is effective to substantially destroy the VOC within compressed air B and provide a mixed combustion gas stream D having a temperature suitable to activate the nozzle and turbine stages of gas turbine <b>26</b>. In accordance with a preferred aspect of the present invention, the mixed-out temperature of mixed stream D provided to turbine <b>26</b> is in the range between about 1500° F. and about 2300° F., preferably about 1850° F.

0037In a conventional fashion, mixed stream D is directed to turbine <b>26</b>. Turbine <b>26</b> of the type generally described above, is initially started by cranking it over with a starter (not shown) to produce air flow through the compressor. At the appropriate speed, fuel C is permitted to flow into combustor <b>16</b>. However, once device <b>10</b> is in operation, mixed stream D suitably powers turbine <b>26</b> in a manner such that the output E from turbine <b>26</b> is suitably harnessed and utilized in subsequent operation of device <b>10</b>, as well as in connection with the production of power for other applications.

0038With reference to <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, the way in which reaction chamber <b>18</b> and combustor <b>16</b> cooperatively work to effectively destroy the VOC's in the VOC laden air in a manner to suitably drive power generator <b>12</b> will now be described in greater detail.

0039Reaction chamber <b>18</b> preferably comprises a double walled vessel having a main, inner wall <b>60</b> and an outer wall <b>62</b> that envelopes inner wall <b>60</b>. The chamber <b>64</b> defined by walls <b>60</b> and <b>62</b> is suitably configured and positioned in proximity to compressor <b>24</b> to receive compressed air B. Preferably, and with reference to <figref idref="DRAWINGS">FIGS. 4 and 5</figref>, chamber <b>64</b> receives compressed air B (containing the secondary fuel) from outlets <b>57</b>A, <b>57</b>B of compressor <b>24</b>. Chamber <b>64</b> extends about the periphery of reaction chamber <b>18</b>. Further, in accordance with a preferred aspect of the present invention, chamber <b>64</b> also suitably communicates with combustor <b>16</b> in the region of respective openings <b>67</b>A and <b>67</b>B by way of a plurality of inlets <b>69</b>, as well as wall <b>60</b> by way of tube outlets <b>124</b>, <b>126</b>. Thus, compressed air B is, in accordance with at least one aspect of the present invention, suitably provided to the combustor <b>16</b> and also directly to chamber <b>64</b> by way of tubes <b>116</b>, <b>118</b>, as will be discussed in further detail below.

0040With reference to <figref idref="DRAWINGS">FIG. 3</figref>, combustor <b>16</b> preferably comprises a hot wall type thermally insulated combustor. Preferably, combustor <b>16</b> comprises an outlet wall <b>80</b> within which a conventional combustion device <b>82</b> is suitably orientated. An inlet <b>84</b> communicates with combustion device <b>82</b> to advantageously effect combustion of fuel C. As previously briefly mentioned, fuel inlet C is preferably directed from fuel supply <b>70</b> through fuel control valve <b>74</b> and compressed air B is provided to combustion device <b>82</b> through inlets <b>69</b>. In accordance with preferred aspects of the present invention, fuel supply C is suitably controlled by a control system <b>150</b> such that a sufficient amount of primary fuel C is provided to combustion chamber to effectively maintain an appropriate equivalence ratio (ER) thereby enabling stoichiometrically correct combustion. As shown best in <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, the outlet <b>86</b> of combustor <b>16</b> suitably communicates with the interior of reaction chamber <b>18</b>.

0041Combustor <b>16</b> may be attached to reaction chamber <b>18</b> in any convenient manner. For example, combustor <b>16</b> can be fixably attached to chamber <b>18</b> such that outlet <b>86</b> of combustor <b>16</b> directly communicates with an opening of reaction chamber <b>18</b> in an in-line manner. However, in accordance with a preferred aspect of the present invention and as shown best in <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, combustor <b>16</b> is attached to reaction chamber <b>18</b> such that combustor <b>16</b> is orthogonal to the central axis X of reaction chamber <b>18</b>. In this manner, as will be described in greater detail below, the combination gases exit outlet <b>86</b> of combustor <b>16</b> tangentially to reaction chamber <b>18</b> thereby tending to create a substantially cyclonic flow of the resulting fuel mixture within reaction chamber <b>18</b>. While combustor <b>16</b> is shown in <figref idref="DRAWINGS">FIG. 4</figref> as being attached to reaction chamber <b>18</b> tangentially near an end of reaction chamber <b>18</b> opposite inlets <b>59</b>a, <b>59</b>b, it should be appreciated that combustion chamber <b>16</b> may be attached in any convenient fashion. For example, combustor <b>16</b> may be attached at any angle from about 0° to about 90° from the central axis X of reaction chamber <b>18</b> and at any point along a side or the top of reaction chamber <b>18</b>.

0042Combustion within combustor <b>16</b> takes place in a generally conventional manner, with the exception that compressed air B, i.e. the VOC laden air introduced into the system, is permitted to mix with the primary fuel C within the later stages of combustor <b>16</b>. As will be appreciated by those skilled in the art, near inlet <b>84</b>, primary fuel C is relatively rich such that it burns under near stoichiometric conditions, typically at a temperature in the range of about 2500° F. to about 3200° F., preferably between about 2800° F. and about 3000° F. and optimally 3000° F. In this region denoted in <figref idref="DRAWINGS">FIGS. 3 and 4</figref> as “P”, often referred to as the “primary zone”, a minor portion of secondary fuel, which is contained within the compressed air is suitably mixed with primary fuel thereby creating a fuel mixture of primary and secondary fuels. The minor portion of secondary fuel introduced into the primary-zone P via inlet <b>69</b> is about 10% to about 30% of the secondary fuel. If the portion falls much below 10%, the fuel will become too rich and thereby cause “rich blowout.” While the amount of secondary fuel introduced into combustor <b>16</b> will vary, in general preferably from about 0 to about 70%, and more preferably from about 0 to about 50% of the fuel necessary to drive power generator <b>12</b> is provided by the secondary fuel.

0043The residence time of the gas mixture of primary fuel and secondary fuel within reaction chamber is enhanced due to the preferred configuration of combustor <b>16</b> relative to reaction chamber <b>18</b>. Specifically, and in accordance with a preferred aspect of the present invention, as the combustion gases exit the combustor at outlet <b>86</b>, such gases are directed toward the opposing wall of reaction chamber <b>18</b>. The flow pattern which results in the interior of reaction chamber <b>18</b> tends to be cyclonic, i.e. creating a spiral pattern.

0044In accordance with a preferred aspect of the present invention, the fuel mixture, comprising primary fuel and secondary fuel is retained in reaction chamber <b>18</b> for a sufficient time to effectively burn, i.e. combust the VOC's contained within the secondary fuel B. Typically, the residence time of the gas mixtures within reaction chamber <b>18</b> is on the order of about 0.25 seconds or more. In accordance with a preferred design of the present invention, the tangential orientation of the combustor relative the reaction chamber has been found to not only enhance residence time, but also to cause a degree of recirculation within reaction chamber <b>18</b> thus further enabling substantially complete destruction of the VOC's within reaction chamber <b>18</b>.

0045In practice, the present invention generally results in an excess of 90%, and typically from between about 95 and 99.5% of the VOC contained within secondary fuel B being effectively broken down into water vapor and carbon dioxide. As will be appreciated, and as will be discussed in greater detail below, through effective operation of device <b>10</b>, substantially all of the VOC's contained within the inlet air A, and thus compressed air B, are thus effectively destroyed within reaction chamber <b>18</b> and/or combustor <b>16</b>.

0046Preferably, flow channels <b>112</b>, <b>114</b> of system <b>110</b> each comprise respective tubes <b>116</b> and <b>118</b>. Preferably, tubes <b>116</b> and <b>118</b> are suitably attached to reaction chamber <b>18</b> at <b>116</b>A, <b>118</b>A and are in fluid communication with chamber <b>64</b> at outlets <b>124</b> and <b>126</b>. Tubes <b>116</b> and <b>118</b> each preferably include respective valves <b>120</b> and <b>122</b>, which may comprise any conventional flow control valve, such as a general poppet-type valve or the like. Tubes <b>116</b>, <b>118</b> are in fluid communication with duct <b>65</b>, which is in fluid communication with chamber <b>64</b>, such that when valves <b>120</b>, <b>122</b> are opened, the pressure differential between chambers <b>18</b> and <b>64</b> pushes a portion of the compressed air B out of chamber <b>64</b> through duct <b>65</b> and into tubes <b>116</b>, <b>118</b>. This portion of compressed air B then travels through the tubes <b>116</b>, <b>118</b> and exits through outlets <b>124</b>, <b>126</b> directly into chamber <b>60</b>, causing air B to thereby bypass the combustor <b>16</b>. In a preferred embodiment, when the valves <b>120</b>, <b>122</b> are closed, all of compressed air B enters combustor <b>16</b> in the region of openings <b>67</b>A and <b>67</b>B via inlets <b>69</b>.

0047Preferably, as shown, channels <b>112</b> and <b>114</b>, as well as duct <b>65</b>, each comprise a single tube that allow for the adequate bypass of compressed air B from chamber <b>64</b> directly into reaction chamber <b>18</b>. However, other arrangements for accomplishing this objective easily can be devised and employed in the context of the present invention. Due to size considerations, generally the number of channels <b>112</b>, <b>114</b> are minimized to two or three, and preferably even one; however, additional channels may be employed as desired.

0048Inlet air control system <b>110</b> can be activated manually or through the computer control associated with control system <b>150</b>, which will now be described.

0049Preferably, control system <b>150</b> is a computer based system suitably configured and arranged to control, among other things, power generator <b>12</b> and fuel supply C, as well as inlet and outlet air from device <b>10</b>. In general, control system <b>150</b> operates in a conventional manner to control power generator <b>12</b> including, among other things, compressor <b>24</b> and turbine <b>26</b>. Further, in a conventional fashion, control system <b>150</b> operates to start device <b>10</b> initially and monitor operation of device <b>10</b> as device <b>10</b> begins to operate due to the burning of primary fuel A and secondary fuel C.

0050Control system <b>150</b>, however, differs from conventional gas turbine and other industrial engine controls in that system <b>150</b> operates to monitor and, as necessary, adjust fuel supplies A and C, as well <b>25</b> air control system <b>110</b> to achieve optimum levels of efficiency and ensure that device <b>10</b> safely and effectively remains operative. Any suitable electronic means that is well known in the art may be utilized for control system <b>150</b>. As previously noted, and with momentary reference to <figref idref="DRAWINGS">FIG. 1</figref>, control system communicates and utilizes information received from sensors <b>42</b>, <b>48</b>, <b>52</b>, and <b>72</b>. In addition, one or more sensors <b>152</b> may be utilized which are incorporated in proximity to or within reaction chamber <b>18</b> or combustor <b>16</b>. (While sensor <b>152</b> is shown in <figref idref="DRAWINGS">FIG. 1</figref> as being outside of both chamber <b>18</b> and combustor <b>16</b>, its location is only illustrative of its position (or the positions) somewhere within fuel control system <b>14</b>). In cooperation, these sensors provide information reflective of, among other things: VOC level in inlet air (e.g. sensor <b>48</b>); temperature and flow rate of inlet air A, compressed air B, fuel C, mixed stream D and the like; fuel content and volume (e.g. sensor <b>74</b>); power output from device <b>10</b>; and speeds of turbine <b>26</b>, with this and other information, control system suitably controls the operation of device <b>10</b>.

0051For example, when the power output of power generator <b>12</b> drops below an expected level for the measured full consumption of fuel C, thus indicating, for example, that the fuel mixture within combustor <b>16</b> may be becoming too lean, control system <b>150</b> may activate control system <b>110</b>. In such cases, valves <b>120</b>, <b>122</b> will be opened thereby creating a pressure difference sufficient to draw compressed air B out of the chamber <b>64</b> and into the bypass flow channels <b>112</b>, <b>114</b>, which in turn, direct compressed air B into reaction chamber <b>18</b> thus preventing its flow into combustor <b>16</b>. Operation of control system <b>150</b> in this manner prevents the fuel mixture within combustor <b>16</b> from becoming too lean, while still allowing for the VOC laden air to be reacted with the primary fuel within reaction chamber <b>18</b> to thereby destroy the VOC concentration and retain the VOC fuel value.

0052Stated another way, control system <b>150</b>, by monitoring the varying VOC level in inlet air A, and thus the corresponding fuel valve of inlet air, adjusts device <b>10</b> for appropriate operation. For example, in the case where inlet air A has a fuel valve in excess of that necessary to drive power generator <b>12</b> at idle alone, control system <b>150</b> suitably reduces the flow of fuel C and as necessary, activates air control system <b>110</b> to prevent generator <b>12</b> from operating at excessive speeds and/or combustor from operating at excessively lean or such levels.

0053Control system <b>150</b> may also be employed to compensate for the relatively long lag time between fuel introduction and changes in conditions at inlet <b>90</b> to turbine <b>26</b> caused by reactions taking place within reaction chamber <b>18</b>, as well as to monitor or control other aspects of device <b>10</b>.

0054In accordance with a further embodiment of the present invention, and with reference to <figref idref="DRAWINGS">FIG. 6</figref>, in some cases, it may be desirable to initially treat VOC laden air from a typical plant prior to destroying the VOC's contained therein. In accordance with this aspect of the present invention, an air treatment system <b>200</b> is advantageously employed and communicates with one or more destruction devices, for example respective destruction devices <b>10</b>A and <b>10</b>B. Destruction devices <b>10</b>A and <b>10</b>B are in a form similar to device <b>10</b> described above. System <b>200</b> suitably comprises an inlet <b>202</b> which cooperates with, for example, inlet air duct <b>40</b>. Inlet air A is thereafter drawn into chamber <b>203</b> where inlet air A is both cooled and sampled to determine the level of VOCs in inlet air A. Preferably, one or more sensors <b>206</b> are suitably carried within chamber <b>203</b> for the purpose of determining the VOC level within inlet air A.

0055In the event inlet air A is determined to be laden with an unacceptable level of VOC, an inlet bypass device <b>208</b> opens to allow fresh air into chamber <b>203</b>. Preferably, bypass device <b>208</b> comprises a shutter valve of conventional design.

0056In addition, inlet air A is suitably cooled to a temperature within an acceptable range. Preferably, such cooling is effected through a heat exchanger system <b>205</b>. Preferably system <b>205</b> comprises respective heat exchange elements <b>204</b>, <b>218</b>, outlet <b>210</b> and cooling fan <b>222</b>. As will be appreciated by those skilled in the art, element <b>204</b> is suitably connected via outlet and duct elements (not shown) to cooling pump <b>211</b> and heat exchange element <b>218</b> such that cooling fluid is suitably recirculated between elements <b>204</b> and <b>218</b>. In a conventional manner, system <b>205</b> allows for the cooling of inlet air A. Inlet air A once cooled, is passed through a centrifugal separator <b>212</b> separating the VOC laden air from any large particles. Once separated, the VOC laden air is communicated to devices <b>10</b>A and <b>10</b>B, preferably by respective conduits <b>214</b> and <b>216</b>. As previously briefly mentioned, devices <b>10</b>A and <b>10</b>B operate in a fashion similar to that of device <b>10</b> described above to generate respective exhausts E<b>1</b>, E<b>2</b> which are released into the plant to provide process heat through respective outlet <b>230</b>, <b>232</b>.

0057With reference to <figref idref="DRAWINGS">FIG. 7</figref>, a further alternative embodiment of the present invention is shown. With certain applications, it may be desirable to utilize a destruction device in accordance with the present invention in a relatively mobile fashion. As shown in <figref idref="DRAWINGS">FIG. 7</figref>, a mobile destruction system <b>300</b> suitably comprises a sled <b>302</b> upon which a destruction device <b>10</b>C is suitably mounted. Destruction device <b>10</b>C is suitably configured in a manner similar to that of device <b>10</b> described hereinabove. As so configured, device <b>10</b>C includes power generator <b>12</b> to which reaction chamber <b>18</b> and combustor <b>16</b> are suitably attached. The output of device <b>10</b>C, namely exhaust E<b>3</b> is suitably communicated via outlet <b>303</b> into a heat recovery air-oil cooler <b>304</b>. In accordance with this embodiment of the present invention, a voltage source <b>306</b> is suitably provided to provide startup power to device <b>10</b>C, as well as power, at least initially, to the other aspects of system <b>300</b>. A gas compressor <b>308</b> is also suitably mounted to sled <b>302</b> for raising gas pressure to levels required by device <b>10</b>C. Respective ventilators <b>310</b>, <b>312</b> may be also suitably mounted to sled <b>302</b>. In addition, a water supply <b>320</b> with respective auxiliary units <b>322</b>, <b>324</b>, <b>326</b>, <b>328</b> and pump <b>330</b> may also be utilized for purposes of water injection into the combustor <b>16</b> to control emissions of nitrous oxide.

0058System <b>300</b> is suitably controlled through operation of a control system <b>350</b> which may be optionally cooled through operation of a refrigeration device <b>352</b>. Various other devices such as ventilators, switch and other electronic devices may be also employed, in a conventional fashion, for a effective use of device <b>10</b>C in connection with mobile system <b>300</b>.

0059Preliminary experimental tests of devices embodying the present invention have indicated that by using the VOC laden secondary fuel, the amount of primary fuel needed to operate the engine is reduced without a loss of energy content in the fuel supply. Accordingly, the use of this volatile organic compound destruction system <b>10</b> results in substantially complete destruction of the volatile organic compound while reducing the amount of primary fuel required to operate an engine for the generation of electricity.

0060Thus, it will be appreciated that device <b>10</b> provides significant advantages over prior art designs for destruction of VOCs. For example, in accordance with experiments preformed using devices embodying preferred aspects of the present invention, substantial destruction of VOC laden air efficiency (e.g. at rates above 99.5%) at a level of about 6200 ft³/min can be obtained with the production of a nominal 525 kw of electrical power.

0061To illustrate the overall impact of the present invention, consider a typical plant using 640,000 kw hours per month with a need to consume 12,000 cubic feet per minute of air laden with 3,500 parts per million of a VOC. Consider further that the plant consumes 97,000 therms of fossil fuel each month. Without control, over 800 metric tons per year of VOC's are released into the atmosphere.

0062While prior art techniques (e.g. use of a thermal oxidizer) may reduce the emission of less than 50 metric tons per year of VOC's, use of such devices increases the plant energy consumption to about 125,000 therms per month.

0063In contradistinction, through use of a device embodying the present invention, effective VOC control is enabled with less energy. Specifically, in this example, the energy consumed and therefore, total fossil fuels burned, falls to 81,000 therms per month. Not only are the total operating costs for the plant reduced, but there is also a net reduction in the emission of carbon dioxide, nitric oxide and sulfur oxide. The sum effect of use of the present invention to control volatile organic emissions is thus cleaner air, less fossil fuel consumption and resulting lower costs.

0064It will be understood that the foregoing description is of the preferred exemplary embodiments of the invention, and that the invention is not limited to the specific forms shown. Various modifications may be made in the design and arrangement of the elements set forth herein without departing from the scope of the invention as expressed in the appended claims.