Patent Publication Number: US-2019170023-A1

Title: Steam and Gas Turbine Device

Description:
The invention relates to a steam and gas turbine device comprising a gas turbine unit (A) and a steam turbine unit (B), wherein the gas turbine unit (A) is partly composed of at least the following: a gas compressor positioned on a compressor axle, a combustion chamber and a gas turbine positioned on a gas turbine axle; and wherein the steam turbine unit (B) is partly composed of the following: a closed steam line in which at least the following are accommodated: a pump; a steam converter, which, in operation, is in heat-exchanging contact with the gases coming from the gas turbine; a steam turbine positioned on a steam turbine axle; as well as a condenser. 
     Steam and gas turbine devices are well known and are used industrially in all kinds of different configurations. An example of a steam and gas turbine device according to the abovementioned introduction is disclosed, for example, in Netherlands patent no. 1028373C1. 
     The abovementioned known variants of known steam and gas turbine devices are relatively complicated devices with a number of constructional drawbacks and limitations with regard to transferring the power generated to a load, as a result of which the overall efficiency of such installations is also limited. 
     A steam and gas turbine device according to the introduction of Claim  1  is disclosed, for example, in German patent publication no. DE102010033659, or British patent publication no. GB671702. 
     The object of the present invention is to provide a steam and gas turbine device according to the abovementioned introduction which does not have the drawbacks associated with the multi-axle and single-axis variant. More particularly, it is an object of the invention to provide a steam and gas turbine device of simple construction and without all kinds of complicated additional components. 
     According to the invention, the steam and gas turbine device according to the invention is characterized by the fact that the gas turbine unit (A) furthermore comprises at least one heat exchanger, which brings the combustible flue gases coming from the combustion chamber into heat-exchanging contact with the gases coming from the gas compressor. 
     As a result thereof, it is possible to deploy the device in a more functional manner and also to implement it in operating conditions with only a combustion chamber. 
     More particularly, the steam converter comprises a steam generator, which, in operation, is in heat-exchanging contact with the combustible flue gases coming from the combustion chamber ( 2 ). 
     With a further functional embodiment, the device furthermore comprises a first air pre-heater, which brings the steam line into heat-exchanging contact with the gases coming from the gas compressor. As a result thereof, the compressed gases coming from the gas compressor are pre-heated by the steam in the steam line, which significantly improves the efficiency of the heat exchanger and the gas turbine. 
     In this case, the first air pre-heater may be accommodated in the device downstream viewed from the steam generator and upstream viewed from the at least one heat exchanger. More specifically, the first air pre-heater is accommodated in the device downstream viewed from the steam turbine. This has the advantage that the steam in the steam line is first passed through the steam turbine at a high temperature, which improves the transfer of power to the steam turbine axle. 
     Furthermore, the device comprises a second air pre-heater, which brings the gases coming from the gas turbine into heat-exchanging contact with the gases coming from the gas compressor. In this case as well, it is possible to achieve an improved efficiency of the device via heat transfer from the gases coming from the gas turbine (having a high temperature) to the gases coming from the gas compressor (having a lower temperature). 
     In this last embodiment, the second air pre-heater is accommodated in the device upstream viewed from the at least one heat exchanger and, more specifically, the second air pre-heater is accommodated in the device downstream viewed from the first air pre-heater. 
     Furthermore, the steam converter may comprise a steam superheater, which, in operation, is in heat-exchanging contact with the gases coming from the gas turbine. In this case, it is also possible to achieve a further heating of the steam in the steam line before passing this steam through the steam turbine. Also as a result thereof, the efficiency of the device is improved. 
     More specifically, the gas turbine is in flow connection with the combustion chamber in order to pass the gases coming from the gas turbine to the combustion chamber. 
     More particularly, the steam turbine and gas compressor are positioned on the same axle. 
     Furthermore, the gas turbine unit (A) comprises a blow-off valve which is arranged upstream of the at least one heat exchanger for blowing off the gases coming from the gas compressor in a controlled manner. 
     In this case, the blow-off valve may be accommodated in the gas turbine unit (A) downstream viewed from the first air pre-heater or in the gas turbine unit (A) upstream viewed from the second air pre-heater or in the gas turbine unit (A) upstream viewed from the gas turbine. 
     Furthermore, the compressor may consist of several compressors situated parallel to each other and/or in series and the turbine may consist of several turbines situated parallel to each other and/or in series and the steam turbine may consist of several steam turbines situated parallel to each other and/or in series. 
     The efficiency of the steam turbine unit may furthermore be improved by the fact that, with a specific embodiment according to the invention, in operation, the water flowing through the steam line is in heat-exchanging contact with the air flowing through the intermediate cooler downstream of the condenser. More particularly, the heat-exchanging contact takes place according to the co-current principle or according to the countercurrent principle. 
     With other embodiments of the steam and gas turbine device according to the invention, the steam turbines may be impulse steam turbines or radial steam turbines, the gas compressors may be centrifugal gas compressors or axial gas compressors and the steam generator may be a once-through waste heat boiler. 
    
    
     
       The invention will now be explained with reference to a drawing, in which: 
         FIGS. 1 a -1 b   - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9  successively show various embodiments of a steam and gas turbine device according to the invention. 
     
    
    
     In order to aid the understanding of the invention, similar components illustrated in the various figures will be denoted by the same reference numerals in the following description of the figures. 
     In the embodiments of a steam and gas turbine device according to the invention illustrated in  FIGS. 1 a  and 1 b   , the gas compressor  1  is shown as being positioned on one axle  4 ,  10 , together with the steam turbine  9 . By means of this configuration of a steam and gas turbine device according to the invention, the power generated by the steam turbine unit (B) is transferred to the gas turbine  3  via the axle  4 ,  10  and the gas compressor  1 , so that all of the power generated by this device is transferred to one axle  5  in order to drive the load  12 . 
     With all the embodiments of the steam and gas turbine device according to the invention described here, the steam turbines may be impulse steam turbines or radial steam turbines, the gas compressors may be centrifugal gas compressors or axial gas compressors and the steam generator may be a once-through waste heat boiler. 
     The characteristic feature of the steam and gas turbine device is the mechanical disengagement of the gas compressor  1  and the gas turbine  3  which are not positioned on the same axle, but are positioned on different axles  4  and  5 , respectively. This mechanical disengagement of the gas compressor  1  and the gas turbine  3  renders the use of additional, complicated coupling mechanisms obsolete. 
     In this embodiment, reference numeral  2  denotes an arbitrary combustion chamber/oven which is fed with fuel which is supplied via the inlet  2   a . Actually, the combustion chamber/oven  2  may be used for any factory process which has a hot (waste) stream as output. The combustion chamber  2  may be of any desired design and may be, for example, a combustion engine or an incinerator, depending on the technical installation which is used in the steam and gas device according to the invention. 
     Reference numeral  20  denotes a heat exchanger which brings the hot (waste) stream coming from the combustion chamber  2 , such as combustible flue gases, into heat-exchanging contact with the gases coming from the gas compressor in compressed form via the outlet  1   b.    
     Following the heat-exchanging contact between the combustible flue gases coming from the combustion chamber  2  and the compressed gases coming from the gas compressor  1 , the latter gases are passed into the gas turbine  3  via the inlet  3   a . The compressed gases which have been heated by the heat-exchanging contact in the heat exchanger  10  drive the gas turbine  3 , as a result of which the latter will start to rotate, together with the gas turbine axle  5 , and will thus drive a load, which is denoted by reference numeral  12  in the figure. 
     The heated gases leave the gas turbine  3  via the outlet  3   b  and are passed to the steam generator  8 . Similarly, the combustible flue gases are passed from the heat exchanger  20  through the steam generator  8  via the outlet  2   b.    
     In the steam generator  8 , the hot gas turbine gases and the hot combustible flue gases are brought into heat-exchanging contact with the water flowing through the closed steam line  6 , so that steam is generated, by means of which the steam turbine  9  is driven. 
     In this steam and gas turbine device, the gas compressor  1  is positioned on one axle  4 ,  10  together with the steam turbine  9 . Using this configuration, the power generated by the steam turbine unit (B) is transferred to the gas turbine  3  via the axle  4 ,  10  and the gas compressor  1 , so that all the power generated by this device is transferred to one axle  5  in order to drive the load  12 . 
     By using the heat exchanger  20  in this embodiment of the steam and gas turbine device according to the invention, the entire unit can easily be coupled to installations which already contain a combustion unit. As a result thereof, the steam and gas turbine device requires few modifications as the heat exchanger  20  can easily be connected to the hot (waste) stream outlet of the combustion chamber  2  which is already present. 
     In the embodiment as illustrated in  FIGS. 1 a  and 1 b   , the steam converter comprises a steam generator  8  which, in operation, brings the steam/water line  6  into heat-exchanging contact with the combustible flue gases coming from the heat exchanger  20  via the outlet  2   b  and also with the gases coming from the gas turbine  3  via the outlet  3   b.    
     One other more efficient embodiment of the steam and gas turbine device is illustrated in  FIG. 2 , wherein the reference numeral  30  comprises a first air pre-heater which brings the steam line  6  through which the compressed gases coming from the gas compressor  1  pass into heat-exchanging contact with the outlet  1   b . Here, the waste heat of the steam passed through the steam/water line  6  is emitted to the gases compressed by the gas compressor  1  and flowing through the outlet  1   b , so that these gases are passed to the heat exchanger  20  in preheated and compressed form via the outlet  1   b.    
     As is illustrated in  FIG. 2 , the first air pre-heater  30  is accommodated in the device downstream viewed from the steam generator  8  and upstream viewed from the heat exchanger  20 . More specifically, as is illustrated in  FIG. 2 , the first air pre-heater  30  brings the outlet  1   b  of the gas compressor into heat-exchanging contact with the steam/water line  6  downstream viewed from the steam turbine  9 . 
     In  FIG. 3 , a particular form of the embodiment of the steam and gas turbine device according to the invention shown in  FIG. 2  is illustrated. In this  FIG. 3 , reference numeral  40  denotes a second air pre-heater which brings the gases coming from the gas turbine  3  into heat-exchanging contact with the gases coming from the gas compressor  1  and more particularly the gases coming from the first air pre-heater  30 . In this embodiment, the gases coming from the gas turbine  3  are passed to the steam converter/steam generator  8  (see outlet  3   b ) after they have passed through the second air pre-heater  40 . An improved energy efficiency is achieved in this case as well in the form of heat recovery, due to the fact that the compressed gases which are released from the gas compressor  1  via the outlet  1   b  are preheated due to the transfer of energy from the gases from the gas turbine  3 . 
     The embodiment in  FIG. 4  is derived from the embodiment from  FIG. 1 , albeit that the steam converter also comprises a steam superheater  50  in addition to a steam generator  8 , so that, in operation, the steam/water line  6  is in heat-exchanging contact with the gases coming from the gas turbine  3 . In this embodiment, these gases are blown off via the outlet  3   b.    
     In this way, a further heating of the steam passed through the steam/water line  6  and generated in the steam generator  8  is further heated in a supercritical manner in order to achieve a more efficient energy conversion in the steam turbine  9 . Optionally, an additional water spray injector may be provided with this steam superheater  50  in order to introduce a water mist into the steam/water line  6 , so that extra steam is generated which can be passed to the steam turbine  9 . 
     A combination of the embodiments from  FIGS. 2 and 4  is illustrated in  FIG. 5 . In this combined embodiment, both a first air pre-heater  30  and a steam superheater  50  are implemented in which the gases coming from the gas turbine  3  are blown off via the outlet  3   b . In this embodiment, the steam conversion in the steam generator  8  only takes place by heat transfer between the combustible flue gases (outlet  2   b ) coming from the combustion chamber  2  and the heat exchanger  20  and the water passed to the steam generator  8  via the pump  7 . 
     In  FIG. 6 , which refers back to the embodiment according to  FIG. 1  in which the gases coming from the gas turbine  3  are not first passed to the steam converter  8 , but are first passed to the combustion chamber  2 , where they are fed to the combustion process. Thus, the gases fed to the combustion chamber  2  via the gas turbine  3  are also passed through the steam generator  8  as combustible flue gases via the outlet  2   b . In this embodiment, the steam generator is thus only supplied with combustible flue gases via the outlet  2   b  which are composed of gases which are passed to the combustion chamber  2  via the inlet  2   a  or via the outlet  3   b  of the gas turbine  3 . 
     A combination of the embodiments from  FIGS. 2 and 6  is illustrated in  FIG. 7 . Also in this embodiment, the gases coming from the gas turbine  3  are passed to the combustion chamber  2  via the outlet  3   b  and the steam/water line  6  is in heat-exchanging contact with the outlet  1   b  downstream viewed from the steam turbine  9 , through which the compressed gases coming from the gas compressor  1  are passed. 
     A combination of the embodiments from  FIGS. 2, 5 and 6  is illustrated in  FIG. 8 . In this embodiment, the steam superheater  50  is implemented which is in heat-exchanging contact with the gases coming from the gas turbine  3  which are passed into the combustion chamber  2  via the outlet  3   b  and of which only the combustible flue gases then come into heat-exchanging contact with the steam/water line  6  in the steam generator  8 . After heating in the steam superheater  50  and after the steam turbine  9 , the steam passed from the steam generator  8  to the steam superheater  50  is, in the first air pre-heater  30 , again brought into heat-exchanging contact with the compressed gases which leave the gas compressor  1  via the outlet  1   b.    
     Thus, a last waste heat which is still present in the steam is efficiently transferred to the compressed gases before being passed through the heat exchanger  20 . 
     It will be clear that, with the illustrated embodiments of the steam and gas turbine device according to the invention, by the implementation of the heat exchanger  20 , the entire device can easily be used with any installation where a hot (waste) stream is generated in an exteral combustion process or any other process. 
     It should furthermore be noted that the heat-exchanging contact in the first and second air pre-heaters  30  and  40 , respectively, between the compressed gases from the gas compressor  1  and the steam in the steam/water line  6 , or in the steam generator  8  and the steam superheater  50 , respectively, between the steam in the steam/water line  6  and the gases coming from the gas turbine  3 /the combustible flue gases coming from the heat exchanger  20  can take place according to the co-current principle or according to the countercurrent principle. 
     In the figures, reference numeral  21  denotes a blow-off valve which, is arranged in any case in all embodiments upstream of the gas turbine  3  (see all figures and in particular  FIG. 1 a   ) and preferably upstream of the at least one heat exchanger  20  (see all figures and in particular  FIGS. 1 b    and  9 ) and serves for blowing off gases coming from the gas compressor  1  via the outlet  1   c . Preferably, the blow-off valve  21  is accommodated in the gas turbine unit (A) downstream viewed from the first air pre-heater  30  ( FIGS. 2, 3, 5, 7, 8 ), whereas the blow-off valve  21  is accommodated in the gas turbine unit (A) upstream viewed from the second air pre-heater  40 , as is illustrated in  FIG. 3 . Optionally, the device may comprise a blow-off valve  21  which is arranged upstream of the gas turbine  3  in order to blow off the gases coming from the gas compressor  1 . 
     In addition to the various variants of a steam and gas turbine device according to the invention illustrated in the  FIGS. 1 a -1 b   - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9  the illustrated variants may be supplemented with an additional advantageous aspect, in which the blow-off valve  21  and the outlet  1   c  are in flow connection with the combustion chamber  2 . With this embodiment, which can be applied to each  FIG. 1 to 9 , the blow-off valve  21  is returned to the combustion chamber  2  via the outlet  1   c . Thus, the gases coming from the gas compressor  1  and which are usually blown off via the blow-off valve  21  and the outlet  1   c , are now returned to the combustion chamber  2 . These additional embodiments provide an additional more efficient combustion and thus energy conversion in the combustion chamber  2  and ultimately also in the heat exchanger  20 . 
     In addition,  FIG. 9  shows an embodiment in which the combustion chamber  2  and the heat exchanger  20  have been integrated with each other such that they form a single entity, resulting in a more efficient energy conversion. The integration of the combustion chamber  2  and the heat exchanger  20  with each other to form a single entity may also be used in the other embodiments which are illustrated in  FIGS. 1 a -1 b   - 2 - 3 - 4 - 5 - 6 - 7 - 8 .