Patent Description:
In at least some known rotary machines, energy is extracted from the combustion of alternative fuels such as bio-diesels, alcohol based fuels (methanol, ethanol, etc.), bio-alcohols, vegetable oils, and/or other biomass fuels. Alternative fuels may be cheaper, more readily available, and may be used for carbon offsets in certain jurisdictions. Additionally, combusting alternative fuels may reduce emissions and may increase an operating range of the rotary machine because a boiling point of the alternative fuel may be lower than a boiling point of a conventional fuel.

However, rotary machines that combust alternative fuels are typically ignited and started with a conventional fuel because alternative fuels are more volatile than conventional fuels. Specifically, because at least some known alternative fuels evaporate at lower temperatures than conventional fuels, rotary machines that combust alternative fuels are first ignited on a liquid conventional fuel, and the rotary machine is transferred to combusting alternative fuels after ignition. It would therefore be desirable to ignite and operate the gas turbine engine using alternative fuels.

<CIT> discloses a method for supplying vaporized fuel oil to a gas turbine and a system for the same. <CIT> discloses a system for supplying a gaseous fuel to a gas turbine including a liquefied fuel source for supplying a liquefied fuel to a liquid fuel pump that is disposed downstream from the liquefied fuel source. The liquid fuel pump is sufficient to raise the pressure of the liquefied fuel to a substantially supercritical pressure. A supercritical liquefied fuel vaporizer is disposed downstream from the liquid fuel pump. A heat recovery system is in thermal communication with the liquefied fuel. The heat recovery system is positioned between the liquid fuel source and the supercritical liquefied fuel vaporizer. <CIT> discloses a gas turbine combustor including a fuel injection nozzle that atomizes liquid fuel into fine liquid droplets. The fuel injection nozzle includes a first system adapted to supply the liquid fuel and a second system adapted to supply a fluid for atomizing the liquid fuel. Low-boiling liquid fuel is supplied to the second system as the fluid. The second system is adapted to heat and supply the low-boiling liquid fuel.

An invention is set out in the claims. In one aspect, a power generation system is provided. In another aspect, a method of generating power using a power generation system is provided.

Unless otherwise indicated, approximating language, such as "generally," "substantially," and "about," as used herein indicates that the term so modified may apply to only an approximate degree, as would be recognized by one of ordinary skill in the art, rather than to an absolute or perfect degree. Accordingly, a value modified by a term or terms such as "about," "approximately," and "substantially" is not to be limited to the precise value specified. Here and throughout the specification and claims, range limitations may be identified. Such ranges may be combined and/or interchanged and include all the sub-ranges contained therein unless context or language indicates otherwise. Additionally, unless otherwise indicated, the terms "first," "second," etc. are used herein merely as labels and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, for example, a "second" item does not require or preclude the existence of, for example, a "first" or lower-numbered item or a "third" or higher-numbered item.

As used herein, the terms "axial" and "axially" refer to directions and orientations extending substantially parallel to a longitudinal axis of a rotary machine. Moreover, the terms "radial" and "radially" refer to directions and orientations extending substantially perpendicular to the longitudinal axis of the rotary machine. In addition, as used herein, the terms "circumferential" and "circumferentially" refer to directions and orientations extending arcuately about the longitudinal axis of the rotary machine. Further, as used herein, the term "upstream" refers to a forward or inlet end of a rotary machine, and the term "downstream" refers to an aft or exhaust end of the rotary machine.

The systems described herein relate to power generation systems that ignite and operate using an alternative fuel, particularly ethanol. Specifically, the power generation system described herein includes a storage and distribution system, a liquid supply system, a vapor supply system, and a combustion system. The storage and distribution system stores a volume of ethanol, and channels a portion of the stored ethanol to the liquid supply system and to the vapor supply system. The liquid supply system receives liquid ethanol from the storage and distribution system and channels the liquid ethanol to the combustion system. The vapor supply system receives ethanol from the storage and distribution system, vaporizes the liquid ethanol into a vapor ethanol that is channeled to the combustion system. The combustion system generates power by igniting the liquid ethanol from the liquid supply system. Exhaust gases from the combustion system are then channeled to a heat recovery steam generator within the vapor supply system, where the heat recovery steam generator generates steam that is channeled to heat exchangers within the vapor supply system. The heat exchangers vaporize the liquid ethanol into a vaporized ethanol that is channeled to the combustion system.

The combustion system initiates combusting liquid ethanol from the liquid supply system and vaporized ethanol from the vapor supply system during a transition period. More specifically, the liquid supply system gradually reduces the volume of the liquid ethanol supplied to the combustion system, and the vapor supply system increases the volume of the vaporized ethanol supplied to the combustion system until the combustion system is combusting only vaporized ethanol. Accordingly, the power generation system described herein ignites and subsequently is operated using an alternative fuel. Typically, power generation systems that generate power using alternative fuels emit less greenhouse gases and have greater operational flexibility than power generation systems that generate power using conventional fuels. Accordingly, the power generation systems described herein facilitate reducing fossil fuel emissions and having greater operational flexibility by generating power with alternative fuels such as ethanol.

<FIG> is a block flow diagram of an exemplary power generation system <NUM> that generates power using an alternative fuel, particularly ethanol. As used herein, conventional fuels are typically fossil fuels, such as, but not limited to, petroleum products, coal, and/or natural gas. Furthermore, while system <NUM> is configured to generate power using alternative fuels, system <NUM> may also generate power using conventional fuels, such as, but not limited to, petroleum products, coal, and/or natural gas (methane).

In the exemplary embodiment, power generation system <NUM> includes a storage and distribution system <NUM>, a liquid supply system <NUM>, a vapor supply system <NUM>, and a combustion system <NUM>. Storage and distribution system <NUM> stores a volume of ethanol and channels a portion of the stored ethanol to liquid supply system <NUM> and to vapor supply system <NUM>. Liquid supply system <NUM> receives liquid ethanol from storage and distribution system <NUM> and channels the liquid ethanol to combustion system <NUM>. Vapor supply system <NUM> receives liquid ethanol from storage and distribution system <NUM>, vaporizes the liquid ethanol into a vapor ethanol, and channels the vapor ethanol to combustion system <NUM>. Additionally, vapor supply system <NUM> may also channel vapor methane to combustion system <NUM>. Combustion system <NUM> generates power by combusting the liquid ethanol from liquid supply system <NUM>, the vapor ethanol from vapor supply system <NUM>, and/or a different fuel from either liquid supply system <NUM> or vapor supply system <NUM>.

In the exemplary embodiment, storage and distribution system <NUM> includes an ethanol storage system <NUM>, a first pump system <NUM>, a first filtration system <NUM>, and a first flow measurement system <NUM>. Ethanol storage system <NUM> includes at least one storage tank (not shown) that receives and stores a volume of ethanol. Ethanol storage system <NUM> may receive ethanol from a pipeline, a nearby production facility, a ship, and/or a tanker truck, for example.

First pump system <NUM> transfers ethanol from ethanol storage system <NUM> to first filtration system <NUM>, to first flow measurement system <NUM>, to liquid supply system <NUM>, and/or to vapor supply system <NUM>. In the exemplary embodiment, first pump system <NUM> includes a pump. In alternative embodiments, first pump system <NUM> includes any type of fluid motive device that enables storage and distribution system <NUM> to operate as described herein.

In the exemplary embodiment, first filtration system <NUM> filters particle and/or debris from the ethanol received from first pump system <NUM> to facilitate protecting downstream equipment from such particles and/or debris that may be entrained within the ethanol received from first pump system <NUM>. First filtration system <NUM> may include any type of filter that enables storage and distribution system <NUM> to operate as described herein.

In the exemplary embodiment, first flow measurement system <NUM> measures the ethanol from first pump system <NUM> in order to better control liquid supply system <NUM> and/or vapor supply system <NUM>. First flow measurement system <NUM> may include any type of flowmeter that enables storage and distribution system <NUM> to operate as described herein. Ethanol is channeled from first flow measurement system <NUM> to liquid supply system <NUM> and/or vapor supply system <NUM>.

In the exemplary embodiment, liquid supply system <NUM> includes a second pump system <NUM>, a second filtration system <NUM>, a second flow measurement system <NUM>, and a flow control and distribution system <NUM>. Second pump system <NUM> transfers ethanol from first flow measurement system <NUM> to second filtration system <NUM>, to second flow measurement system <NUM>, to flow control and distribution system <NUM>, and/or to combustion system <NUM>. In the exemplary embodiment, second pump system <NUM> includes a pump. In alternative embodiments, second pump system <NUM> includes any type of fluid motive device that enables liquid supply system <NUM> to operate as described herein.

In the exemplary embodiment, second filtration system <NUM> filters particles and/or debris from the ethanol received from second pump system <NUM> to protect downstream equipment from such particles and/or debris that may be entrained within the ethanol received from second pump system <NUM>. Second filtration system <NUM> may include any type of filter that enables liquid supply system <NUM> to operate as described herein. Liquid supply system <NUM> may also include a Safety Shutoff Valve (SSOV) to protect the equipment within liquid supply system <NUM> and/or combustion system <NUM>.

In the exemplary embodiment, second flow measurement system <NUM> measures the ethanol from second pump system <NUM> in order to control liquid supply system <NUM> and/or combustion system <NUM>. Second flow measurement system <NUM> may include any type of flowmeter that enables liquid supply system <NUM> to operate as described herein. In the exemplary embodiment, flow control and distribution system <NUM> controls the ethanol from flow measurement system <NUM> to combustion system <NUM>. Flow control and distribution system <NUM> includes valves, actuators, and/or other flow control equipment that controls delivery or flow rate of ethanol to combustion system <NUM>. Ethanol is channeled from flow control and distribution system <NUM> to combustion system <NUM>.

In the exemplary embodiment, vapor supply system <NUM> includes a third pump system <NUM>, a vaporization system <NUM>, a methane supply system <NUM>, a heat recovery steam generator (HRSG) <NUM>, an inertial separator <NUM>, a third flow measurement system <NUM>, and a gas control system <NUM>. Third pump system <NUM> transfers ethanol from first flow measurement system <NUM> to vaporization system <NUM>, to inertial separator <NUM>, to third flow measurement system <NUM>, to gas control system <NUM>, and/or to combustion system <NUM>. In the exemplary embodiment, third pump system <NUM> includes a pump. In alternative embodiments, third pump system <NUM> includes any type of fluid motive device that enables vapor supply system <NUM> to operate as described herein.

In the exemplary embodiment, vaporization system <NUM> vaporizes the ethanol from third pump system <NUM>. Vaporization system <NUM> includes at least one heat exchanger <NUM> that transfers heat from a heat exchange medium from HRSG <NUM> to the ethanol from third pump system <NUM> to cause the ethanol from third pump system <NUM> to vaporize. In alternative embodiments, vaporization system <NUM> includes a plurality of heat exchangers <NUM> that vaporize the ethanol from third pump system <NUM>. In the exemplary embodiment, components of vaporization system <NUM> downstream of heat exchangers <NUM> are heat traced (as indicated by parallel hash marks on <FIG>) to preheat equipment within vaporization system <NUM> in order to receive vaporized ethanol from heat exchangers <NUM>. Heat tracing within vaporization system <NUM> may also be used to preheat equipment within vaporization system <NUM> in order to receive methane from methane supply system <NUM>.

In the exemplary embodiment, methane supply system <NUM> channels methane into vaporization system <NUM> downstream from heat exchanger <NUM>. The heating value of methane is similar to the heating value of ethanol, such that combustion system <NUM> is able to combust either ethanol vapor or methane. As such, methane can be used as an alternate fuel source if ethanol is not available. Thus, methane supply system <NUM> supplies combustion system <NUM> with methane if ethanol is not available. Additionally, methane supply system <NUM> may supply methane to supplement the vaporized ethanol. Accordingly, methane supply system <NUM> increases the operational flexibility of power generation system <NUM>.

In the exemplary embodiment, HRSG <NUM> receives exhaust gases from combustion system <NUM> and transfers heat from the exhaust gases to a heat exchange medium. HRSG <NUM> also channels a heat exchange medium to heat exchangers <NUM> and receives a heat exchange medium from heat exchangers <NUM>. In the exemplary embodiment, HRSG <NUM> includes a heat exchanger that recovers heat from the exhaust gases from combustion system <NUM> and transfers the recovered heat to a heat exchange medium. In the exemplary embodiment, the heat exchange medium includes liquid water and/or steam. However, the heat exchange medium may include any type of heat transfer fluid that enables vapor supply system <NUM> to operate as described herein.

HRSG <NUM> and heat exchangers <NUM> form a closed loop circuit that channels the heat exchange medium from HRSG <NUM> and heat exchangers <NUM> and from heat exchangers <NUM> back to HRSG <NUM>. As such, HRSG <NUM> increases the temperature of the heat exchange medium by transferring heat from the exhaust gases to the heat exchange medium, and heat exchangers <NUM> decrease the temperature of the heat exchange medium by transferring heat from the heat exchange medium to the ethanol to vaporize the ethanol.

In the exemplary embodiment, inertial separator <NUM> separates liquids that may be entrained in the vaporized ethanol from vapor ethanol. The vaporized ethanol from vaporization system <NUM> may include liquids entrained in the vapor ethanol. Specifically, liquid ethanol droplets may be entrained in the vaporized ethanol and/or the heat exchange medium may leak into the vaporized ethanol because of a failure within heat exchangers <NUM>. In the exemplary embodiment, inertial separator <NUM> includes a centrifugal separator. However, inertial separator <NUM> may include any other type of separator that enables vapor supply system <NUM> to operate as described herein. In the exemplary embodiment, components of inertial separator <NUM> downstream from heat exchangers <NUM> are heat traced (as indicated by parallel hash marks on <FIG>) to preheat equipment within inertial separator <NUM> in order to receive vaporized ethanol from heat exchangers <NUM>.

In the exemplary embodiment, third flow measurement system <NUM> measures the vaporized ethanol from inertial separator <NUM> in order to control vapor supply system <NUM> and/or combustion system <NUM>. Third flow measurement system <NUM> measures the flow of vaporized ethanol but does not control the flow of vaporized ethanol. Flow measurement is used for tabulating or totaling flow consumption when operating only on ethanol vapor or can be used as a method of controlling mixture or blend ratios during periods of operation when mixtures of both methane and ethanol vapor are used. Third flow measurement system <NUM> may include any type of flowmeter that enables vapor supply system <NUM> to operate as described herein.

In the exemplary embodiment, gas control system <NUM> controls the vaporized ethanol from third flow measurement system <NUM> to combustion system <NUM>. Gas control system <NUM> includes valves, actuators, and/or other flow control equipment oriented to control the vaporized ethanol to combustion system <NUM>. The vaporized ethanol is channeled from gas control system <NUM> to combustion system <NUM>. In the exemplary embodiment, components of third flow measurement system <NUM> and gas control system <NUM> downstream from heat exchangers <NUM> are heat traced (as indicated by parallel hash marks on <FIG>) to preheat equipment within third flow measurement system <NUM> and gas control system <NUM> in order to receive vaporized ethanol from heat exchangers <NUM>.

In the exemplary embodiment, combustion system <NUM> is a gas turbine engine. Alternatively, combustion system <NUM> may be any other turbine engine and/or rotary machine, including, without limitation, a gas turbofan aircraft engine and/or other aircraft engine.

<FIG> is an enlarged schematic view of an exemplary combustion system <NUM>. In the exemplary embodiment, combustion system <NUM> includes an intake section <NUM>, a compressor section <NUM> that is downstream from intake section <NUM>, a combustor section <NUM> that is downstream from compressor section <NUM>, a turbine section <NUM> that is downstream from combustor section <NUM>, and an exhaust section <NUM> that is downstream from turbine section <NUM>. Turbine section <NUM> is coupled to compressor section <NUM> via a rotor shaft <NUM>. It should be noted that, as used herein, the term "couple" is not limited to a direct mechanical, thermal, electrical, and/or flow communication connection between components but may also include an indirect mechanical, thermal, electrical, and/or flow communication connection between multiple components.

In the exemplary embodiment, combustor section <NUM> includes a plurality of combustors <NUM> and a plurality of fuel nozzles (not shown). Combustor section <NUM> is coupled to compressor section <NUM> such that each combustor <NUM> is in flow communication with the compressor section <NUM>. Rotor shaft <NUM> is also coupled to a load <NUM> such as, but not limited to, an electrical generator and/or a mechanical drive application. In the exemplary embodiment, each of compressor section <NUM> and turbine section <NUM> includes at least one rotor assembly <NUM> that is coupled to rotor shaft <NUM>.

In operation, intake section <NUM> channels air <NUM> towards compressor section <NUM>. Compressor section <NUM> compresses inlet air <NUM> to higher pressures prior to discharging compressed air <NUM> towards combustor section <NUM>. Compressed air <NUM> is channeled to combustor section <NUM> where it is mixed with the ethanol from liquid supply system <NUM> and/or the ethanol from vapor supply system <NUM> and burned to generate high temperature combustion gases <NUM>. More specifically, the ethanol from liquid supply system <NUM> is channeled at a high pressure to the fuel nozzles. The fuel nozzles atomize the ethanol from liquid supply system <NUM> such that the atomized ethanol mixes with compressed air <NUM>. Combustion gases <NUM> are channeled downstream towards turbine section <NUM> and impinge upon turbine blades (not shown), converting thermal energy to mechanical rotational energy that is used to drive rotor assembly <NUM> about a longitudinal axis <NUM>. Often, combustor section <NUM> and turbine section <NUM> are referred to as a hot gas section of combustion system <NUM>. Exhaust gases <NUM> are then discharged through exhaust section <NUM> to HRSG <NUM>.

During operation of power generation system <NUM>, storage and distribution system <NUM> channels ethanol to liquid supply system <NUM>, and liquid supply system <NUM> channels the ethanol to combustion system <NUM>. Combustion system <NUM> is ignited using liquid ethanol from liquid supply system <NUM>. Accordingly, combustion system <NUM> is started using an alternative fuel. Exhaust gases <NUM> from combustion system <NUM> are channeled to HRSG <NUM>. Once combustion system <NUM> has achieved a minimum operating load combusting liquid ethanol, vapor supply system <NUM> begins vaporizing ethanol and channeling the vaporized ethanol to combustion system <NUM>. That is, once the temperature of exhaust gases is high enough to vaporize ethanol, vapor supply system <NUM> begins vaporizing ethanol and channeling the vaporized ethanol to combustion system <NUM>. Combustion system <NUM> then begins combusting liquid ethanol from liquid supply system <NUM> and vaporized ethanol from vapor supply system <NUM> during a transition period. Liquid supply system <NUM> reduces the volume of the liquid ethanol, and vapor supply system <NUM> increases the volume of the vaporized ethanol until combustion system <NUM> is combusting only vaporized ethanol. Accordingly, power generation system <NUM> ignites and operates combustion system <NUM> using an alternative fuel.

In an alternative operational mode, methane supply system <NUM> channels methane into vaporization system <NUM> downstream of heat exchanger <NUM> such that the methane mixes with the vaporized ethanol. As such, the methane supplements the vaporized ethanol, and combustion system <NUM> operates on a mixture of vaporized ethanol and methane. In another alternative operational mode, methane supply system <NUM> channels methane into vaporization system <NUM> downstream of heat exchanger <NUM>, and vaporization system <NUM> is not vaporizing ethanol. As such, combustion system <NUM> operates on methane only.

<FIG> is a block flow diagram of an exemplary power generation system <NUM> that generates power with an alternative fuel and is ignited on methane only. More specifically, combustion system <NUM> is ignited using only methane, enabling exhaust gases <NUM> to heat HRSG <NUM>. HRSG <NUM> increases the temperature of the heat exchange medium by transferring heat from the exhaust gases to the heat exchange medium, and heat exchangers <NUM> decrease the temperature of the heat exchange medium by transferring heat from the heat exchange medium to the ethanol to vaporize the ethanol. As such, combustion of the methane allows vaporization system <NUM> to begin producing vaporized ethanol. The vaporized ethanol is then blended with the methane, and combustion system <NUM> begins operating on a blend of methane and vaporized ethanol. Combustion system <NUM> either remains operating on the blend of methane and vaporized ethanol or switches over to operating on only vaporized ethanol.

Power generation system <NUM> is substantially similar to power generation system <NUM> except, in power generation system <NUM>, liquid supply system <NUM>, vaporization system <NUM>, inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> do not include heat tracing. Alternatively, power generation system <NUM> may include liquid supply system <NUM> but liquid supply system <NUM> is idle during operation of power generation system <NUM>.

During operation of power generation system <NUM>, methane is channeled from methane supply system <NUM> through vaporization system <NUM>, inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> to combustion system <NUM>. Combustion system <NUM> is ignited using methane from methane supply system <NUM>. Exhaust gases <NUM> from combustion system <NUM> are channeled to HRSG <NUM>.

Once combustion system <NUM> has achieved a minimum operating load combusting methane, vapor supply system <NUM> begins vaporizing ethanol and channeling the vaporized ethanol to combustion system <NUM>. That is, once the temperature of exhaust gases is high enough to vaporize ethanol, vapor supply system <NUM> begins vaporizing ethanol and channeling the vaporized ethanol to combustion system <NUM>. More specifically, vapor supply system <NUM> mixes the vaporized ethanol with methane, and combustion system <NUM> then begins combusting the mixture of methane from methane supply system <NUM> and vaporized ethanol from vapor supply system <NUM> during a transition period. Methane supply system <NUM> reduces the volume of methane, and vapor supply system <NUM> increases the volume of the vaporized ethanol until combustion system <NUM> is combusting only vaporized ethanol. Accordingly, power generation system <NUM> ignites combustion system <NUM> using a conventional fuel (e.g., methane) and operates combustion system <NUM> using an alternative fuel (e.g., vaporized ethanol).

Power generation system <NUM> may also include a steam pipe <NUM> coupled to HRSG <NUM> and inertial separator <NUM>. In some operating modes, combustion of methane generates exhaust gases <NUM> that heat HRSG <NUM>. HRSG <NUM> generates steam that is channeled into inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> to preheat equipment within inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> in order to begin receiving vaporized ethanol from vaporization system <NUM>.

<FIG> is a block flow diagram of an exemplary power generation system <NUM> that generates power with an alternative fuel and that is ignited using liquid ethanol. Power generation system <NUM> is substantially similar to power generation system <NUM>, except vapor supply system <NUM> also includes an auxiliary boiler <NUM>, and steam pipe <NUM> is coupled to HRSG <NUM>, auxiliary boiler <NUM>, and inertial separator <NUM>. Combustion system <NUM> is ignited using liquid ethanol, and auxiliary boiler <NUM> preheats equipment within inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> in order to receive vaporized ethanol from vaporization system <NUM>.

While auxiliary boiler <NUM> is preheating portions of vapor supply system <NUM>, exhaust gases <NUM> heat HRSG <NUM>. HRSG <NUM> increases the temperature of the heat exchange medium by transferring heat from the exhaust gases to the heat exchange medium, and heat exchangers <NUM> decrease the temperature of the heat exchange medium by transferring heat from the heat exchange medium to the ethanol to vaporize the ethanol. As such, combustion of the liquid ethanol allows vaporization system <NUM> to begin producing vaporized ethanol. The vaporized ethanol is then blended with the liquid ethanol and combustion system <NUM> begins operating on a blend of liquid ethanol and vaporized ethanol. Preheating portions of vapor supply system <NUM> with auxiliary boiler <NUM> enables vapor supply system <NUM> to quickly begin producing vaporized ethanol and to quickly switch to operating only on vaporized ethanol.

During operation of power generation system <NUM>, steam pipe <NUM> channels steam from auxiliary boiler <NUM> and/or HRSG <NUM> into inertial separator <NUM>. The steam preheats equipment within inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> in order to receive vaporized ethanol from vaporization system <NUM>. Auxiliary boiler <NUM> generates steam using electricity, combustion of natural gas, combustion of ethanol, and/or any other source of energy. Storage and distribution system <NUM> then channels ethanol to liquid supply system <NUM>, and liquid supply system <NUM> channels the ethanol to combustion system <NUM>. Combustion system <NUM> is ignited using liquid ethanol from liquid supply system <NUM>. Accordingly, combustion system <NUM> is started using an alternative fuel. Exhaust gases <NUM> from combustion system <NUM> are channeled to HRSG <NUM>.

Once combustion system <NUM> has achieved a minimum operating load combusting liquid ethanol, vapor supply system <NUM> begins vaporizing ethanol and channeling the vaporized ethanol to combustion system <NUM>. That is, once the temperature of exhaust gases is high enough to vaporize ethanol, vapor supply system <NUM> begins vaporizing ethanol and channeling the vaporized ethanol to combustion system <NUM>. Combustion system <NUM> then begins combusting liquid ethanol from liquid supply system <NUM> and vaporized ethanol from vapor supply system <NUM> during a transition period. Liquid supply system <NUM> reduces the volume of the liquid ethanol, and vapor supply system <NUM> increases the volume of the vaporized ethanol until combustion system <NUM> is combusting only vaporized ethanol. Accordingly, power generation system <NUM> ignites and operates combustion system <NUM> using an alternative fuel.

During an alternative operational mode of power generation system <NUM>, steam from auxiliary boiler <NUM> is channeled into inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> to preheat equipment within inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM>. After auxiliary boiler <NUM> has preheated portions of vapor supply system <NUM>, methane is channeled from methane supply system <NUM> through vaporization system <NUM>, inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> to combustion system <NUM>. Combustion system <NUM> is ignited using methane from methane supply system <NUM>. Exhaust gases <NUM> from combustion system <NUM> are channeled to HRSG <NUM>.

Once combustion system <NUM> has achieved a minimum operating load combusting methane, vapor supply system <NUM> begins vaporizing ethanol and channeling the vaporized ethanol to combustion system <NUM>. That is, once the temperature of exhaust gases is high enough to vaporize ethanol, vapor supply system <NUM> begins vaporizing ethanol and channeling the vaporized ethanol to combustion system <NUM>. More specifically, vapor supply system <NUM> mixes the vaporized ethanol with methane, and combustion system <NUM> then begins combusting the mixture of methane from methane supply system <NUM> and vaporized ethanol from vapor supply system <NUM> during a transition period. Methane supply system <NUM> reduces the volume of the methane, and vapor supply system <NUM> increases the volume of the vaporized ethanol until combustion system <NUM> is combusting only vaporized ethanol. Accordingly, power generation system <NUM> ignites combustion system <NUM> using a conventional fuel (e.g., methane) and operates combustion system <NUM> using an alternative fuel (e.g., vaporized ethanol).

<FIG> is a block flow diagram of an exemplary power generation system <NUM> that generates power with an alternative fuel. Power generation system <NUM> is substantially similar to power generation system <NUM>, except vapor supply system <NUM> also includes a steam or water supply pipe <NUM> also coupled to auxiliary boiler <NUM> and heat exchangers <NUM> of vaporization system <NUM> and a steam or condensate return pipe <NUM> coupled to auxiliary boiler <NUM> and heat exchangers <NUM> of vaporization system <NUM>. Steam or water supply pipe <NUM> channels steam or water from auxiliary boiler <NUM> to heat exchangers <NUM> of vaporization system <NUM> to vaporize the ethanol from third pump system <NUM>. Steam or condensate return pipe <NUM> channels steam or condensate from heat exchangers <NUM> of vaporization system <NUM> back to auxiliary boiler <NUM>. Auxiliary boiler <NUM> generates steam using electricity, combustion of natural gas, combustion of ethanol, and/or any other source of energy.

During operation of power generation system <NUM>, steam from auxiliary boiler <NUM> is channeled to heat exchangers <NUM> of vaporization system <NUM>. Simultaneously, third pump system <NUM> pumps liquid ethanol to vaporization system <NUM>, and steam from auxiliary boiler <NUM> vaporizes the liquid ethanol. Storage and distribution system <NUM> then channels ethanol to liquid supply system <NUM>, and liquid supply system <NUM> channels the ethanol to combustion system <NUM>. Combustion system <NUM> is ignited using liquid ethanol from liquid supply system <NUM>. Accordingly, combustion system <NUM> is started using an alternative fuel. Combustion system <NUM> then begins combusting liquid ethanol from liquid supply system <NUM> and vaporized ethanol from vapor supply system <NUM> during a transition period. Liquid supply system <NUM> reduces the volume of the liquid ethanol, and vapor supply system <NUM> increases the volume of the vaporized ethanol until combustion system <NUM> is combusting only vaporized ethanol. Exhaust gases <NUM> from combustion system <NUM> are channeled to HRSG <NUM>.

Once combustion system <NUM> has achieved a minimum operating load combusting liquid ethanol, HRSG <NUM> begins channeling steam to vaporization system <NUM>, and auxiliary boiler <NUM> reduces production of steam until HRSG <NUM> is producing all steam necessary to vaporize the liquid ethanol. Accordingly, power generation system <NUM> ignites and operates combustion system <NUM> using an alternative fuel.

During an alternative operational mode of power generation system <NUM>, steam from auxiliary boiler <NUM> is channeled into inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM> by steam pipe <NUM> to preheat equipment within inertial separator <NUM>, third flow measurement system <NUM>, and gas control system <NUM>. Steam from auxiliary boiler <NUM> is also channeled to heat exchangers <NUM> of vaporization system <NUM> to vaporize the ethanol from third pump system <NUM> using steam supply pipe <NUM>. Vapor supply system <NUM> vaporizes the ethanol and channels the vaporized ethanol to combustion system <NUM>. Combustion system <NUM> is then ignited and operated using vaporized ethanol from vapor supply system <NUM>. Accordingly, combustion system <NUM> is started using a vaporized alternative fuel. Exhaust gases <NUM> from combustion system <NUM> are channeled to HRSG <NUM>.

Once combustion system <NUM> has achieved a minimum operating load combusting vaporized ethanol, HRSG <NUM> begins channeling steam to vapor supply system <NUM>. That is, once the temperature of exhaust gases is high enough to vaporize ethanol, HRSG <NUM> begins channeling steam to vapor supply system <NUM> and vapor supply system <NUM> begins vaporizing ethanol using the steam from HRSG <NUM>. Combustion system <NUM> then begins combusting vaporized ethanol that has been vaporized using steam from HRSG <NUM> rather than auxiliary boiler <NUM>. Accordingly, power generation system <NUM> ignites and operates combustion system <NUM> using a vaporized alternative fuel.

<FIG> is a flow diagram of an exemplary method <NUM> of generating power using power generation system <NUM> (shown in <FIG>). Power generation system <NUM> includes combustion system <NUM>, liquid supply system <NUM>, and vapor supply system <NUM>. Vapor supply system <NUM> includes HRSG <NUM> and vaporization system <NUM>. In the exemplary embodiment, method <NUM> includes channeling <NUM> a first liquid alternative fuel from liquid supply system <NUM> to combustion system <NUM>. Method <NUM> also includes igniting <NUM> combustion system <NUM> with the first liquid alternative fuel from liquid supply system <NUM> by combusting the first liquid alternative fuel. Combustion of the first liquid alternative fuel generates power and exhaust gases. Method <NUM> further includes channeling <NUM> the exhaust gases from combustion system <NUM> to HRSG <NUM>. Method <NUM> also includes heating <NUM> a heat exchange medium within HRSG <NUM> using the exhaust gases. Method <NUM> further includes channeling <NUM> the heat exchange medium from HRSG <NUM> to vaporization system <NUM>. Method <NUM> also includes vaporizing <NUM> a second liquid alternative fuel using the heat exchange medium to generate a vapor alternative fuel. Method <NUM> further includes channeling <NUM> the vapor alternative fuel to combustion system <NUM>. Method <NUM> also includes operating <NUM> combustion system <NUM> by combusting the vapor alternative fuel.

<FIG> is a flow diagram of an exemplary method <NUM> of generating power using power generation system <NUM> (shown in <FIG>). Power generation system <NUM> includes combustion system <NUM> and vapor supply system <NUM>. Vapor supply system <NUM> includes vaporization system <NUM> and auxiliary boiler <NUM>. Method <NUM> includes generating <NUM> steam using auxiliary boiler <NUM>. Method <NUM> also includes channeling <NUM> the steam from auxiliary boiler <NUM> to vaporization system <NUM>. Method <NUM> further includes vaporizing <NUM> a liquid alternative fuel using the steam to generate a vapor alternative fuel. Method <NUM> also includes channeling <NUM> the vapor alternative fuel to combustion system <NUM>. Method <NUM> further includes igniting and operating <NUM> combustion system <NUM> by combusting the vapor alternative fuel.

The above described power generation systems ignite and operate using an alternative fuel. Specifically, the power generation system described herein includes a storage and distribution system, a liquid supply system, a vapor supply system, and a combustion system. The storage and distribution system stores a volume of an alternative fuel, such as ethanol, and channels a portion of the stored ethanol to the liquid supply system and to the vapor supply system. The liquid supply system receives liquid ethanol from the storage and distribution system and channels the liquid ethanol to the combustion system. The vapor supply system receives ethanol from the storage and distribution system, vaporizes the liquid ethanol into a vapor ethanol that is channeled to the combustion system. The combustion system generates power by igniting the liquid ethanol from the liquid supply system. Exhaust gases from the combustion system are then channeled to a heat recovery steam generator within the vapor supply system, where the heat recovery steam generator generates steam that is channeled to heat exchangers within the vapor supply system. The heat exchangers vaporize the liquid ethanol into a vaporized ethanol that is channeled to the combustion system.

The combustion system initiates combusting liquid ethanol from the liquid supply system and, during a transition period, operates using liquid ethanol and vaporized ethanol from the vapor supply system. More specifically, the liquid supply system reduces the volume of the liquid ethanol, and the vapor supply system increases the volume of the vaporized ethanol until the combustion system is combusting only vaporized ethanol. Accordingly, the power generation system described herein ignites and subsequently is operated using an alternative fuel. Typically, power generation systems that generate power using alternative fuels emit less greenhouse gases and have greater operational flexibility than power generation systems that generate power using conventional fuels. Accordingly, the power generation systems described herein facilitate reducing fossil fuel emissions and have greater operational flexibility by generating power with alternative fuels such as ethanol.

Additionally, an exemplary technical effect of the systems and methods described herein includes at least one of: (a) igniting a combustion system using a liquid alternative fuel; (b) igniting a combustion system using a vapor alternative fuel; and (c) operating a combustion system using a vapor alternative fuel.

Exemplary embodiments of systems and methods for generating power using an alternative fuel are described above in detail. The methods and systems are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the method may also be used in combination with other power generation systems and are not limited to practice only with the other power generation systems as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other power generation applications.

Although specific features of various embodiments of the present disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of embodiments of the present disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

Claim 1:
A power generation system (<NUM>) comprising:
a gas turbine engine (<NUM>) configured to generate power by combusting ethanol;
a liquid ethanol supply system (<NUM>) configured to channel liquid ethanol to said gas turbine engine (<NUM>);
a vapor ethanol supply system (<NUM>) configured to channel vaporized ethanol to said gas turbine engine (<NUM>); and
an ethanol storage system (<NUM>) configured to channel liquid ethanol to the liquid ethanol supply system (<NUM>) and the vapor ethanol supply system (<NUM>);
wherein:
the gas turbine engine is configured to be ignited and to generate power and exhaust gases by combusting the liquid ethanol;
the vapor ethanol supply system (<NUM>) comprises a heat recovery steam generator (<NUM>) and is configured to channel the exhaust gases from the gas turbine engine (<NUM>) to the heat recovery steam generator (<NUM>) and to heat an exchange medium within the heat recovery steam generator (<NUM>) using the exhaust gases;
the vapor ethanol supply system (<NUM>) further comprises a heat exchanger (<NUM>) and is configured to channel the heat exchange medium from the heat recovery steam generator (<NUM>) to the heat exchanger (<NUM>);
the heat exchanger (<NUM>) is configured to vaporize liquid ethanol using the heat exchange medium to generate the vaporized ethanol; and
the power generation system is further configured to channel the vaporized ethanol to the gas turbine engine (<NUM>) and to operate the gas turbine engine (<NUM>) by combusting the vaporized ethanol;
wherein, after igniting (<NUM>) the gas turbine engine (<NUM>) with the liquid ethanol, the liquid ethanol supply system (<NUM>) is configured to reduce the volume of liquid ethanol supplied to the gas turbine engine (<NUM>) and the vapor ethanol supply system (<NUM>) is configured to increase the volume of vaporized ethanol supplied to the gas turbine engine (<NUM>) until the gas turbine engine is combusting only vaporized ethanol.