Patent Description:
Globally, the majority of hydrogen is generated by the means of a steam methane reforming process. In the steam methane reforming process, synthesis gas is generated by reforming hydrocarbon feedstock and is subsequently shifted to a water gas shift reactor to produce a shifted gas stream. To purify the hydrogen from the shifted gas stream, other components such as water, methane, carbon monoxide, carbon dioxide, or nitrogen need to be removed and typically a pressure swing adsorption (PSA) purification unit is installed in a process plant for this. Prior the separation of hydrogen, hot shift gas stream needs to be cooled down to a temperature level of approximately <NUM> before entering the PSA purification unit. The sensible heat of the synthesis gas leaving a steam reformer and the shifted gas leaving the water gas shift reactor is typically recovered by the production of steam or preheating of other process streams such as hydrocarbon feed stream, boiler feedwater, or demineralized water. However, a portion of the sensible heat from the synthesis gas cannot be recovered and is finally cooled by air coolers or cooling water coolers. This portion of sensible heat is basically lost energy and cannot be recovered.

Typically, power generators have been integrated into the process plants for utilizing the lost energy. However, small size power generators are expensive for the amount of power generated by the power generators. Hence, commercial application is often not justified considering the total investment and operating cost.

Some existing approaches use an organic Rankine cycle power generation system to utilize aforesaid waste heat to generate electricity. For example, published European patent application <CIT> proposes to recover heat from steam reforming gas streams using a Rankine cycle heat engine to generate power, wherein the Rankine cycle heat engine uses a working fluid like propane, butane, pentane, ethylene, propylene, lithium bromide in water and mixtures thereof.

The power generation system receives heat from the organic fluid that is heated using syngas as a heat source. Then, preheated organic fluid is vaporized using a vaporizer. The vaporized organic fluid is expanded through a turbine system to generate electricity. However, the electrical efficiency of aforesaid power generation system is rather low compared to traditional electrical power generating systems and cost of such system are also high.

Furthermore, the cost of the integration of such power generation system into the process plants is also high. Typically, a separate heat exchanger is installed in a syngas heat recovery section, preferably downstream of a CO shift stage (shift gas cooler), for cooling a syngas stream to a lower temperature syngas stream and preheat a cold-water stream. The preheated water stream provides the necessary heat to operate the power generation system. A water circulation system with a pump is required for circulating the cold-water stream and preheated water stream. Hence, to extract the heat necessary for the operation of the power generator system, an additional heat exchanger, heat exchanger, e. , shift gas cooler, and the water circulation system with pump are required. These additional equipment items and associated piping increase the installation cost to a level that such an integration is commercially not justified.

The biggest disadvantages of the power generation system in the context of the process plants are high cost of the power generation systems and high installation cost of such power generation systems into the process plants.

Therefore, there is a need to address the aforementioned technical drawbacks in existing known technologies in order to improve co-generation of electricity in the process plant by using low-grade or low-temperature heat from process streams. Further prior art systems and methods are disclosed in <CIT>, <CIT> and <CIT>.

The present invention seeks to provide an approach for improving co-generation of electricity in a process plant by utilizing a minimum number of additional equipment with minimum impact on design of the process plant. An aim of the present invention is to provide a solution that overcomes at least partially aforesaid problems encountered in prior art and provide an improved method for co-generating electricity in a process plant that is integrated with a thermal power plant by routing a portion of a pressurized feedwater to the thermal power generator for supplying heat to the thermal power generator. The object of the present invention is achieved by solutions provided in the herewith appended independent claim. Advantageous implementations of the present invention are further defined in the herewith appended dependent claims.

According to a first aspect, the present invention provides a method for co-generating electricity in a process plant using feedwater, wherein the process plant is integrated with a thermal power generator, wherein the method comprises:.

The method for co-generating electricity in the process plant according to present invention is of advantage in that the method provides an improved process for integration of the thermal power generator with the process plant by routing the second stream of feedwater to the thermal power generator to supply heat for electricity co-generation. Such improved process of integration leads to elimination of additional equipment, namely a shift gas cooler and a circulation pump for integration of the thermal power generator, thereby lowering an installation cost and an operational cost.

According to a second aspect, the present invention provides a method for co-generating electricity in a process plant using feedwater, where the process plant is integrated with a thermal power generator, the method comprises:.

The method for co-generating electricity in the process plant according to present invention is of advantage in that the method provides an improved process for integration of the thermal power generator with the process plant by routing the second stream of feedwater to the thermal power generator to supply heat for electricity co-generation. Further, the method enables efficient cogeneration of electricity by utilizing heat from the preheated mixed stream of feedwater. Such improved process of integration leads to elimination of additional equipment, namely a shift gas cooler and a circulation pump for integration of the thermal power generator, thereby lowering an installation cost and an operational cost.

Additional embodiments of the present invention are capable of eliminating the aforementioned drawbacks in existing known approaches for co-generating electricity in a process plant using feedwater. The advantage of the embodiments according to the present invention is that the embodiments provide an improved process for integrating the thermal power plant with the process plant by eliminating requirement of an additional shift gas cooler as well as a circulation pump in the process plant, thus lowers an installation cost and an operational cost.

Additional aspects, advantages, features and objects of the present invention are made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow. It will be appreciated that features of the present invention are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

To illustrate the present invention, exemplary constructions are shown in the drawings. However, the present invention is not limited to specific methods disclosed herein but also includes the combinations which result from the dependencies of the appended claims.

Wherever possible, the same elements have been indicated by identical numbers. Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein:.

The following detailed description illustrates embodiments of the present invention and ways in which they can be implemented.

According to a first aspect, the present invention provides a method for co-generating electricity in a process plant using feedwater, wherein the process plant is integrated with a thermal power generator, wherein the method comprises: obtaining a pressurized stream of hot feedwater from a feedwater generation unit of the process plant; compressing the pressurized stream of hot feedwater by pumping and splitting the pressurized stream of hot feedwater to obtain a first stream of feedwater and a second stream of feedwater; routing the second stream of feedwater to the thermal power generator; cooling the second stream of feedwater against a process fluid that is used in the thermal power generator to generate a heat in the thermal power generator and to obtain a cooled second stream of feedwater; and co-generating the electricity, using the thermal power generator integrated with the process plant, using the heat.

The apparatus for co-generating electricity in the process plant is of advantage in that the method provides an improved process for integration of the thermal power generator with the process plant by routing the second stream of feedwater to the thermal power generator to supply heat for electricity co-generation. Such improved process of integration leads to elimination of additional equipment, namely a shift gas cooler and a circulation pump for integration of the thermal power generator, thereby lowering an installation cost and an operational cost.

The method for co-generating electricity in a process plant using feedwater has less impact on the design of the process plant.

Optionally, the thermal power generator includes a heater for heating and vaporizing the process fluid using heat of the feedwater, a turbine for extracting thermal energy from the vaporized process fluid and rotating an output shaft using the thermal energy, an electric power generator that is connected with the turbine, for generating electricity, a cooler for cooling the process fluid, and a pump for circulating the process fluid within the thermal power generator.

Optionally, the second stream of feedwater includes a temperature of approximately <NUM>.

Optionally, the method includes mixing at least a portion of the cooled second stream of feedwater with the first stream of feedwater to obtain a mixed stream of feedwater; preheating the mixed stream of feedwater using a hot synthesis gas stream to obtain a preheated mixed stream of feedwater; and routing the preheated mixed stream of feedwater to a steam generator of the process plant.

Optionally, the method includes routing a portion of the cooled second stream of feedwater to the steam generator of the process plant without prior additional heating being used.

Optionally, the method includes preheating the first stream of feedwater using the hot synthesis gas stream to obtain a preheated first stream of feedwater that is routed to the steam generator.

Optionally, the method includes preheating the first stream of feedwater using a hot flue gas stream that is obtained from a combustion process of the thermal power generator.

Optionally, the hot synthesis gas stream is generated by a steam methane reformer. The steam methane reformer may generate the hot synthesis gas stream at a temperature typically between <NUM>-<NUM>.

Optionally, the hot synthesis gas stream is generated by an autothermal reformer. The autothermal reformer may generate the hot synthesis gas stream at a temperature typically between <NUM>-<NUM>.

Optionally, the hot synthesis gas stream is generated by a partial oxidation (POX) process. The POX process may generate the hot synthesis gas stream at a temperature typically between <NUM>-<NUM>.

Optionally, the hot synthesis gas is generated by any combination of the aforesaid synthesis gas generation methods.

Optionally, the method includes sending at least a portion of the cooled second stream of feedwater to the feedwater generation unit of the process plant.

Optionally, the method includes re-utilizing at least a portion of the cooled second stream of feedwater within a reforming process of the thermal power generator.

Optionally, the method includes admixing at least a portion of the cooled second stream of feedwater upstream in a pump that provides feedwater compression.

Optionally, the method includes sending at least a portion of the preheated first stream of feedwater to the thermal power generator for performing heat transfer.

Optionally, the pressurized stream of hot feedwater is split into a first portion and a second portion. Optionally, the method further includes sending the first portion to the thermal power generator for heat transfer and to obtain the cooled second stream of feedwater; and mixing the cooled second stream of feedwater with the second portion prior to compression.

Optionally, the method includes re-mixing the cooled second stream of feedwater with the pressurized stream of hot feedwater, or (b) sending back the cooled second stream of feedwater to the feedwater generation unit.

Optionally, the method includes importing the pressurized stream of hot feedwater to the reforming process from an external feedwater generation unit; and (ii) sending at least a portion of the pressurized stream of hot feedwater to the thermal power generator for heat transfer.

Optionally, the method includes (i) importing the preheated first stream of feedwater, having a lower pressure than the pressurized stream of hot feedwater, to the reforming process, and (ii) sending at least a portion of the preheated first stream of feedwater to the thermal power generator for heat transfer.

Optionally, the method includes preheating the cooled second stream of feedwater, having a lower pressure than the pressurized stream of hot feedwater, using either (a) the hot synthesis gas stream or (b) the hot flue gas stream to obtain a preheated stream; importing the preheated stream to the reforming process; and sending at least a portion of the preheated stream to the thermal power generator for heat transfer.

Optionally, the method includes (i) importing the cooled second stream of feedwater, having a lower pressure than the pressurized stream of hot feedwater, to the reforming process, and (ii) reducing a temperature of a synthesis gas outlet connected to a demineralized water preheater to a level suitable for a pressure swing adsorption process.

Optionally, the method includes (i) importing the cooled second stream of feedwater, having a lower pressure than the pressurized stream of hot feedwater, to the reforming process, and (ii) using at least a portion of the cooled second stream of feedwater obtained from the thermal power generator for final cooling of the hot synthesis gas stream.

Optionally, the method includes utilizing a hot process stream for supplying heat to the thermal power generator before the pressurized stream of hot feedwater is preheated again.

Optionally, the invention provides a method for co-generating electricity in a process plant using feedwater, wherein the process plant is integrated with a thermal power generator, wherein the method comprises: obtaining a pressurized stream of hot feedwater from a feedwater generation unit of the process plant; compressing the pressurized stream of hot feedwater by pumping and splitting the pressurized stream of hot feedwater to obtain a first stream of feedwater and a second stream of feedwater, wherein the first stream of feedwater is routed to a preheater; routing the second stream of feedwater to the thermal power generator; cooling the second stream of feedwater against a process fluid that is used in the thermal power generator to generate a heat in the thermal power generator and to obtain a cooled second stream of feedwater; co-generating the electricity, using the thermal power generator integrated with the process plant, using the heat; mixing at least a portion of the cooled second stream of feedwater with the first stream of feedwater to obtain a mixed stream of feedwater; preheating the mixed stream of feedwater using a hot synthesis gas stream to obtain a preheated mixed stream of feedwater; and routing the preheated mixed stream of feedwater to the thermal power generator for heat transfer and for electricity generation.

The method for co-generating electricity in the process plant using feedwater is of advantage in that the method enables lowering an installation cost and an operation cost by eliminating additional equipment for integrating the thermal power generator to the process plant.

Optionally, the process plant is a synthesis gas production plant that is integrated with the thermal power generator for electricity generation.

Embodiments of the present invention substantially eliminate or at least partially address the aforementioned technical drawbacks in existing technologies in improving electricity co-generation process by routing a portion of a pressurized feedwater with a temperature of approximately <NUM> to a thermal power generator to provide heat to the power generator. The feedwater stream returning from the thermal power generator has a lower temperature and may be mixed with the remaining pressurized feedwater in downstream of a feedwater flow control valve prior to preheating in the preheater.

<FIG> is a schematic illustration of an apparatus <NUM> for co-generating electricity in a process plant using feedwater. The apparatus <NUM> includes a syngas generator <NUM>, a steam generator <NUM>, a water gas shift reactor <NUM>, a preheater <NUM>, a syngas cooler <NUM>, a condensate separator <NUM>, a hydrogen recovery unit <NUM>, a feedwater generation unit <NUM>, a pump <NUM>, a control valve <NUM>, and a thermal power generator <NUM>. The syngas generator <NUM> receives hydrocarbon feedstock and produces a raw synthesis gas stream. The raw synthesis gas stream may be generated at a temperature typically between <NUM> - <NUM> for steam reforming and <NUM> - <NUM> for autothermal reforming (ATR) or a partial oxidation (POX) process. The steam generator <NUM> receives the raw synthesis gas stream and cools the raw synthesis gas stream, thereby producing a cooled syngas stream and a steam stream. The water gas shift reactor <NUM> receives the cooled syngas stream and shifts the cooled syngas stream by converting at least a portion of carbon monoxide (CO) and water (H<NUM>O) into hydrogen (H<NUM>) and carbon dioxide (CO<NUM>), thus obtaining a shifted synthesis gas. The preheater <NUM> receives the shifted synthesis gas (hot synthesis gas stream) and cools the shifted synthesis gas, thereby obtaining a cooled shifted synthesis gas. The syngas cooler <NUM> further cools the cooled shifted synthesis gas and provides the cooled shifted synthesis gas to the condensate separator <NUM>. The condensate separator <NUM> separates a process condensate stream (liquid condensate) from the cooled shifted synthesis gas before directing the latter to the hydrogen recovery unit <NUM> and provides the process condensate stream to the feedwater generation unit <NUM>. The hydrogen recovery unit <NUM> produces an offgas stream as well as a hydrogen stream from the cooled shifted synthesis gas. The hydrogen recovery unit <NUM> may be a pressure swing absorption (PSA) hydrogen recovery unit. The feedwater generation unit <NUM> produces a feedwater stream from the process condensate stream. The feedwater generation unit <NUM> may be a deaerator to remove dissolved gases from the process condensate stream. The feedwater generation unit <NUM> may also comprise a fresh water supply. The fresh water supplied to the feedwater generation unit <NUM> may be demineralized water.

The pump <NUM> obtains a pressurized stream of hot feedwater from the feedwater generation unit <NUM>. The pump <NUM> compresses and/or conveys the pressurized stream of hot feedwater by pumping and splitting the pressurized stream of hot feedwater to obtain a first stream of feedwater and a second stream of feedwater. The first stream of feedwater is routed to the preheater <NUM> via the control valve <NUM>. Optionally, the split between the first and second stream of feedwater is adjusted by setting the control valve <NUM> accordingly. The second stream of feedwater is routed to the thermal power generator <NUM> and cooled against a process fluid that is used in the thermal power generator <NUM> to generate a heat in the thermal power generator <NUM> and to obtain a cooled second stream of feedwater. The electricity is co-generated, using the thermal power generator <NUM> integrated with the process plant using the heat. Optionally, the thermal power generator <NUM> is a Rankine cycle power generator. Optionally, a portion of the cooled second stream of feedwater is mixed with the first stream of feedwater to obtain a mixed stream of feedwater. The mixed stream of feedwater is preheated in preheater <NUM>, using the hot synthesis gas stream leaving the water gas shift reactor <NUM>, to obtain a preheated mixed stream of feedwater and routed to the steam generator <NUM>. The first stream of feedwater may be preheated using the hot synthesis gas stream to obtain a preheated first stream of feedwater that is routed to the steam generator <NUM>. Optionally, the first stream of feedwater may be preheated using a hot flue gas stream that is obtained from a combustion process of the thermal power generator <NUM>.

Optionally, the hot synthesis gas stream is generated by a steam methane reformer, an autothermal reformer or a partial oxidation (POX) process.

<FIG> is a schematic illustration of a first configuration of the apparatus <NUM> of <FIG> for co-generating electricity in a process plant using feedwater.

In the first configuration, the apparatus <NUM> is configured to obtain the pressurized stream of hot feedwater from the feedwater generation unit <NUM> of the process plant. The apparatus <NUM> is configured to compress and/or convey the pressurized stream of hot feedwater by pumping and splitting the pressurized stream of hot feedwater to obtain the first stream of feedwater and the second stream of feedwater. The apparatus <NUM> routes the second stream of feedwater to the thermal power generator. The apparatus <NUM> cools the second stream of feedwater against the process fluid that is used in the thermal power generator to produce heat in the thermal power generator for co-generating the electricity and to obtain the cooled second stream of feedwater. The apparatus <NUM> routes the cooled second stream of feedwater directly towards the steam generator <NUM> without prior additional heating being used. The first stream of feedwater may be preheated in preheater <NUM> using the hot synthesis gas stream to obtain a preheated first stream of feedwater that is routed to the steam generator <NUM>.

<FIG> are schematic illustrations of a second configuration of the apparatus <NUM> of <FIG> for co-generating electricity in a process plant using feedwater.

In the second configuration of <FIG>, the apparatus <NUM> is configured to obtain the pressurized stream of hot feedwater from the feedwater generation unit <NUM> of the process plant. The apparatus <NUM> compresses and/or conveys the pressurized stream of hot feedwater by pumping and splitting the pressurized stream of hot feedwater to obtain the first stream of feedwater and the second stream of feedwater. The apparatus <NUM> routes the second stream of feedwater to the thermal power generator. The apparatus <NUM> cools the second stream of feedwater against the process fluid that is used in the thermal power generator to produce heat in the thermal power generator for co-generating the electricity and to obtain the cooled second stream of feedwater.

<FIG> illustrates a first variation of the second configuration of the apparatus <NUM>.

In the first variation, the apparatus <NUM> is configured to route at least a portion of the cooled second stream of feedwater returning from the thermal power generator <NUM> directly to the feedwater generation unit <NUM>. The first stream of feedwater may be preheated using the hot synthesis gas stream to obtain a preheated first stream of feedwater that is routed to the steam generator <NUM>.

<FIG> illustrates a second variation of the second configuration of the apparatus <NUM>. In the second variation, the apparatus <NUM> is configured to route at least a portion of the cooled second stream of feedwater returning from the thermal power generator <NUM> directly to a suction side of the pump <NUM>. The first stream of feedwater may be preheated using the hot synthesis gas stream to obtain a preheated first stream of feedwater that is routed to the steam generator <NUM>.

<FIG> illustrates a third variation of the second configuration of the apparatus <NUM>.

In the third variation, the apparatus <NUM> is configured to route at least a portion of the cooled second stream of feedwater returning from the thermal power generator <NUM> directly to any other water consumer unit. At least the portion of the cooled second stream of feedwater may be admixed upstream in the pump <NUM> that provides feedwater compression.

Optionally, at least the portion of the second stream of feedwater returning from the thermal power generator <NUM> is directly routed to the feedwater generation unit <NUM>, suction side of the pump <NUM> and any other water consumer unit. The first stream of feedwater may be preheated using the hot synthesis gas stream to obtain a preheated first stream of feedwater that is routed to the steam generator <NUM>. <FIG> illustrates a fourth variation of the second configuration of the apparatus <NUM>.

In the fourth variation, the apparatus <NUM> is configured to (i) preheat, by the preheater <NUM>, at least a portion of the compressed pressurized first stream of feedwater using the hot synthesis gas stream to obtain a preheated first stream of feedwater, and (ii) route at least a part of the preheated first stream of feedwater to the thermal power generator <NUM> for heat transfer and for electricity generation. Optionally, the remaining part of the preheated first stream of feedwater is routed to the steam generation <NUM>. The cooled second stream of feedwater is directed to at least one of the feedwater generation unit <NUM>, the suction side of the pump <NUM> or any other water consumer unit. At least a portion of a preheated first stream of feedwater may be sent to the thermal power generator <NUM> for performing heat transfer.

<FIG> illustrates a fifth variation of the second configuration of the apparatus <NUM>.

In the fifth variation, the apparatus <NUM> is configured to (i) preheat, by the preheater <NUM>, a first stream of feedwater using the hot synthesis gas stream to obtain a preheated first stream of feedwater, and (ii) route at least a part of the preheated first stream of feedwater to the thermal power generator <NUM> for heat transfer and for electricity generation. The apparatus <NUM> optionally includes a control valve <NUM>. Optionally, the split between the portions of the preheated first stream of feedwater being routed to the thermal power generator <NUM> and/or to the steam generation <NUM> is adjusted by setting the control valve <NUM> accordingly. The remaining portion of the preheated first stream of feedwater may be directed to the steam generator <NUM>. The cooled second stream of feedwater is directly routed to the steam generator <NUM>.

<FIG> illustrates a sixth variation of the second configuration of the apparatus <NUM>.

In the sixth variation, the apparatus <NUM> is configured to obtain the pressurized stream of hot feedwater from the feedwater generation unit <NUM> of the process plant and compress, using the pump <NUM>, the pressurized stream of hot feedwater. The apparatus <NUM> preheats, using the preheater <NUM>, the compressed stream of feedwater using the hot synthesis gas stream to obtain a preheated stream of feedwater and routes at least a part of the preheated stream of feedwater to the thermal power generator <NUM>. The apparatus <NUM> cools the preheated stream of feedwater against the process fluid that is used in the thermal power generator <NUM> to produce heat in the thermal power generator <NUM> for co-generating the electricity and to obtain the cooled stream of feedwater. The remaining portion of the preheated stream of feedwater may be directed to the steam generator <NUM>. The cooled stream of feedwater may be routed to feedwater generation unit <NUM> or the suction side of the pump <NUM> or other water consumer unit. <FIG> is a schematic illustration of a third configuration of the apparatus <NUM> of <FIG> for co-generating electricity in a process plant using feedwater.

In the third configuration, the apparatus <NUM> is configured to route at least a portion of the stream of hot feedwater as heat carrier stream before compression towards the thermal power generator <NUM> for electricity generation and to obtain a cooled stream feedwater. The cooled stream feedwater from the thermal power generator <NUM> is sent to the suction side of the pump <NUM> to obtain a mixed stream of feedwater. Optionally, the apparatus <NUM> is configured to compress and/or convey, using the pump <NUM>, the mixed stream of feedwater and preheat, using the preheater <NUM>, the compressed mixed stream of feedwater. The apparatus <NUM> routes the preheated mixed stream of feedwater to the steam generator <NUM>. Optionally, the feedwater generation unit <NUM> may operate at an elevated pressure to allow for an additional pressure drop.

<FIG> are schematic illustrations of a fourth configuration of the apparatus <NUM> of <FIG> for co-generating electricity in a process plant using feedwater.

In the fourth configuration of the apparatus <NUM>, the feedwater preparation may occur outside of process plant in an external feedwater generator <NUM>.

<FIG> illustrates a first variation of the fourth configuration of the apparatus <NUM>.

In the first variation, the apparatus <NUM> is configured to import a pressurized stream of hot feedwater with a suitable temperature to a reforming process, from the external feedwater generator <NUM> and send at least a portion of the pressurized stream of hot feedwater directly to the thermal power generator <NUM> for heat transfer. The pressurized stream of hot feedwater may possess a temperature of at minimum <NUM>. The thermal power generator <NUM> provides a cooled stream of feedwater that may be used as cooling media of syngas in the preheater <NUM>. The cooled stream of feedwater may be preheated using either (a) the hot synthesis gas stream or (b) the hot flue gas stream to obtain a preheated feedwater stream. The preheated feedwater stream may be imported for steam generation in the steam generator <NUM>. The cooled feedwater stream may have lower pressure than the pressurized stream of hot feedwater.

The imported pressurized stream of hot feedwater may not be at suitable temperature level for the thermal power generator <NUM> and additional preheating may be required. Such additional heating may be performed in the preheater <NUM>.

Optionally, the apparatus <NUM> is configured to import a preheated first stream of feedwater, having a lower pressure than the pressurized stream of hot feedwater, to the reforming process, and send at least a portion of the preheated first stream of feedwater to the thermal power generator <NUM> for heat transfer.

<FIG> illustrates a second variation of the fourth configuration of the apparatus <NUM>.

In the second variation, the apparatus <NUM> is configured to import pressurized stream of hot feedwater from the external feedwater generator <NUM> and route the imported pressurized stream of hot feedwater to the preheater <NUM>. The apparatus <NUM> preheats, in the preheater <NUM>, the pressurized stream of hot feedwater by cooling the hot synthesis gas stream to obtain a preheated feedwater stream. The apparatus <NUM> routes at least a portion of preheated feedwater stream to the thermal power generator <NUM> for heat transfer and to obtain a cooled stream of feedwater. The cooled stream of feedwater from the thermal power generator <NUM> is admixed with the pressurized stream of hot feedwater from the feedwater generation unit <NUM> or a feedwater stream from the pump <NUM> to obtain a mixed stream of feedwater. Optionally, the cooled stream of feedwater is sent to the feedwater generation unit <NUM>. Optionally, the mixed stream of feedwater is preheated in the preheater <NUM> and at least a portion of the preheated stream of feedwater is directed to the steam generation <NUM> or the thermal power generator <NUM>.

<FIG> is a schematic illustration of a fifth configuration of the apparatus <NUM> of <FIG> for co-generating electricity in a process plant using feedwater.

In the fifth configuration, the apparatus <NUM> is configured to import demineralized feedwater stream from an external demineralized water generator <NUM> outside the process plant, and routes at least a portion of the import demineralized feedwater stream to the thermal power generator <NUM> for electricity generation and to obtain a cooled demineralized feedwater stream. The imported demineralized water stream provides a temperature level suitable for the thermal power generator <NUM>. The imported demineralized water stream may possess a temperature of minimum <NUM>. The cooled demineralized feedwater stream from the thermal power generator <NUM> is admixed with the pressurized stream of hot feedwater from the feedwater generation unit <NUM> or a feedwater stream from the pump <NUM>, to obtain a mixed stream of feedwater. Optionally, the cooled demineralized feedwater stream is sent to the feedwater generation unit <NUM>. Optionally, the mixed stream of feedwater is preheated in the preheater <NUM> and the preheated mixed stream of feedwater is directed to the steam generation <NUM>.

<FIG> is a schematic illustration of a sixth configuration of the apparatus <NUM> of <FIG> for co-generating electricity in a process plant using feedwater.

In the sixth configuration, the apparatus <NUM> is configured to import demineralized feedwater stream from an external demineralized water generator <NUM> outside the process plant. The apparatus <NUM> routes the import demineralized feedwater stream to a demineralized water preheater <NUM> for preheating the demineralized feedwater stream using the hot synthesis gas stream from the preheater <NUM>, to obtain preheated demineralized feedwater stream and a cooled synthesis gas stream. The apparatus <NUM> routes at least a portion of the preheated demineralized feedwater stream to the thermal power generator <NUM> for electricity generation and to obtain a cooled stream of feedwater. The imported demineralized water stream may not at suitable temperature level such that the imported demineralized water stream is preheated. In the sixth configuration, the syngas cooler <NUM> is obsolete. The cooled stream of feedwater from the thermal power generator <NUM> may be directed to the feedwater generation unit <NUM>. <FIG> is a schematic illustration of a seventh configuration of the apparatus <NUM> of <FIG> for co-generating electricity in a process plant using feedwater.

In the seventh configuration, the apparatus <NUM> is configured to import demineralized feedwater stream from an external demineralized water generator <NUM> outside the process plant. The apparatus <NUM> routes the import demineralized feedwater stream to a demineralized water preheater <NUM> for preheating the demineralized feedwater stream using the hot synthesis gas stream from the preheater <NUM>, to obtain preheated demineralized feedwater stream and a cooled synthesis gas stream. The apparatus <NUM> routes at least a portion of the preheated demineralized feedwater stream to the thermal power generator <NUM> for electricity generation and to obtain a cooled stream of feedwater. Optionally, a portion of the preheated demineralized feedwater stream is sent to the feedwater generation unit <NUM>. The demineralized water preheater <NUM> is located between the preheater <NUM> and the syngas cooler <NUM>. Optionally, temperature of the synthesis gas outlet connected to the demineralized water preheater <NUM> is reduced to a level suitable for a pressure swing adsorption process, using the syngas cooler <NUM>. The cooled stream of feedwater from the thermal power generator <NUM> may be directed to the feedwater generation unit <NUM>. <FIG> is a schematic illustration of an eighth configuration of the apparatus <NUM> of <FIG> for co-generating electricity in a process plant using feedwater.

In the eighth configuration, the apparatus <NUM> is configured to import demineralized feedwater stream from an external demineralized water generator <NUM> outside the process plant. The apparatus <NUM> routes the import demineralized feedwater stream to a demineralized water preheater <NUM> for preheating the demineralized feedwater stream using the hot synthesis gas stream from the preheater <NUM>, to obtain preheated demineralized feedwater stream and a cooled synthesis gas stream. The apparatus <NUM> routes at least a portion of the preheated demineralized feedwater stream to the thermal power generator <NUM> for electricity generation and to obtain a cooled stream of feedwater. Optionally, the cooled stream of feedwater is directed to the syngas cooler <NUM> as a cooling media for cooling the synthesis gas.

Claim 1:
A method for co-generating electricity in a process plant using feedwater, wherein the process plant is integrated with a thermal power generator (<NUM>), wherein the method comprises:
obtaining a pressurized stream of hot feedwater from a feedwater generation unit (<NUM>) of the process plant;
compressing the pressurized stream of hot feedwater by pumping and splitting the pressurized stream of hot feedwater to obtain a first stream of feedwater and a second stream of feedwater;
routing the second stream of feedwater to the thermal power generator (<NUM>);
cooling the second stream of feedwater against a process fluid that is used in the thermal power generator (<NUM>) to generate a heat in the thermal power generator (<NUM>) and to obtain a cooled second stream of feedwater; and
co-generating the electricity, using the thermal power generator (<NUM>) integrated with the process plant, using the heat.