EP2467589A1

EP2467589A1 - Method and device for converting thermal energy from biomass into mechanical work

Info

Publication number: EP2467589A1
Application number: EP10742153A
Authority: EP
Inventors: Dragan Stevanovic´
Original assignee: Krones AG
Current assignee: Krones AG
Priority date: 2009-08-21
Filing date: 2010-08-12
Publication date: 2012-06-27
Also published as: CA2771146A1; EA201290058A1; US20120137701A1; CN102625877A; DE102009038322A1; AU2010285056A1; CN102625877B; BR112012003588A2; US8561412B2; JP2013502527A; UA107580C2; WO2011020768A1; NZ598333A

Abstract

The invention relates in particular to a method for converting thermal energy from carbonaceous raw materials into mechanical work, having at least one first (4) and one second (6) device for storing and releasing thermal energy connected to least intermittently alternatingly in a turbine branch (T) having a gas turbine (8) connected downstream thereof, comprising the steps of: a) combusting a gas in a gas combustor (2); b) passing the smoke gases (3) arising in the gas combustor (2) through a device (4, 6) for storing thermal energy; and c) feeding the hot air released by at least one device (4, 6) into the gas turbine (8), wherein the hot air (7) released by the gas turbine (8) is fed to at least one heat exchanger () connected downstream of the gas turbine (8).

Description

description

The invention relates to a method for the conversion of thermal energy from biomass into mechanical work, according to the preamble of claim 1 and a device for the conversion of thermal energy into mechanical work, according to the preamble of claim 7. The invention is described with reference to biomass However, it should be noted that the inventive method and the device according to the invention can also be used for other carbonaceous products. DE 100 39 246 C2 relates to a method for converting thermal energy into mechanical work, wherein a first and a second means for storing thermal energy are switched on alternately in a turbine branch. The disadvantage here is the inadequate integration of the heat released in the various process steps and the formation of dust in the flue gases, which is removed, for example, by means of a cyclone.

The object of the present invention is therefore to provide a method and a device for converting thermal energy from combustion or gasification of carbonaceous raw materials into mechanical work, which has high efficiency and high efficiency with improved heat integration into the combustion process exhibit and advantageous while avoiding dust in the flue gases work. Furthermore, a method is to be created which in turn efficiently supplies the resulting energies to individual processes.

This is achieved by a method according to claim 1 and by a device according to claim 7. Advantageous embodiments and further developments are the subject of the dependent claims.

An essential point of the invention is that a method for the conversion of thermal energy from carbonaceous raw materials into mechanical work with at least a first and a second means for storing and dispensing thermal energy, which alternately at least temporarily in a turbine branch with a downstream Gas turbine are turned on, the following steps:

a) burning a fuel in a gas burner, wherein the gas burner combustion air is supplied,

b) passing the resulting in the gas burner flue gases by a device for storing thermal energy, and

c) introducing the hot air emitted by at least one device for storing and delivering thermal energy into the gas turbine, in particular its expander, wherein hot air emitted by the gas turbine is supplied to at least one heat exchanger connected downstream of the gas turbine and by means of this heat exchanger the combustion air supplied to the gas burner is heated.

The term downstream is understood in particular to be a downstream in relation to the respective gases to be processed or the heat flow. The gas burner is advantageous immediately downstream of a carburetor. The device for storing thermal energy is preferably also suitable for emitting the stored thermal energy, for example in the form of hot air. As devices for storing thermal energy in particular bulk material generators can be used, as described for example in EP 0 620 909 B1 or DE 42 36 619 C2. The disclosure content of DE 100 39 246 A1, filed on 1 Aug. 2008 at the DPMA, is incorporated by reference in its entirety into the present disclosure By the procedure according to the invention, the power output of the system can be increased by a more targeted lambda control of the system is made.

Thus, the invention proposes to heat combustion air for the gas burner with the advantageous use of the output from the gas turbine heat or hot air by means of a heat exchanger. In this case, additionally compressed air can be supplied to the heat exchanger. The method thus enables optimal heat integration in the combustion process. Thus, the heat formed during the combustion by means of the heat exchanger as heated combustion air is supplied to the gas burner again to further increase the efficiency of the process.

The hot air supplied by the gas turbine and supplied to at least one heat exchanger downstream of the expander of the gas turbine is preferably at least partially supplied as hot exhaust air to at least one further heat exchanger and the recovered thermal energy is decoupled as usable heat. This further contributes to environmental compatibility and to increasing the efficiency of the process.

The hot air supplied by the gas turbine and fed to at least one gas turbine downstream of the gas turbine is preferably at least partially supplied as hot exhaust air to at least one further heat exchanger and the recovered thermal energy is used for the generation of saturated steam. In this embodiment, the waste heat is used for saturated steam generation. This relates in particular to the supply of waste heat to at least one further heat exchanger, which in turn is connected downstream of the gas turbine downstream heat exchanger, with which water is heated to produce the saturated steam.

Additionally or alternatively, the hot air supplied by the gas turbine and supplied to at least one of the gas turbine downstream is preferably at least partially supplied as hot exhaust air to at least one further heat exchanger, and the generated thermal energy is used for the production of hot air. This hot air can be fed to a carburetor.

The overall process preferably comprises, in a first step, gasification of the carbonaceous raw materials in a gasifier, the product gas being used as fuel Carburetor downstream gas burner is supplied. In this case, the heated saturated steam and / or the hot air are preferably introduced via the gas turbine downstream heat exchanger in the gasifier and used as a gasification agent for gasification. Preferably, a fixed-bed countercurrent carburetor is used as the carburetor. In this case, the heated by means of a heat exchanger steam is introduced into the carburetor and used for gasification. Together with the steam, the gasifier is advantageously fed to a further gaseous medium as combustion gas. As combustion gas comes z. As hot air, oxygen, oxygen-enriched air and the like into consideration. In principle, different types of carburetors according to the prior art can be used. However, the particular advantage of a countercurrent fixed bed gasifier is that within this reactor individual zones are formed in which different temperatures and thus different processes occur. The different temperatures are based on the fact that the respective processes are strongly endothermic and the heat only comes from below. In this way, the very high steam temperatures are utilized in a particularly advantageous manner.

In a further preferred method, relaxed hot air from the gas turbine is used to generate energy by means of a steam turbine. In this case, this steam turbine could be integrated into a separate water cycle and the water in this circuit can be vaporized and overheated by a heat exchanger. After the steam turbine, the steam is condensed to be then pressurized in liquid form by a pump before being returned to the heat exchanger. The inventive device for converting thermal energy into mechanical work essentially comprises a gas burner for burning a fuel; at least one first and one second means for storing thermal energy, which at least temporarily alternately in a turbine branch with a downstream gas turbine are switched on and at least one connecting line, which in the gas burner resulting flue gases to the means for storing thermal energy, wherein the gas turbine at least one heat exchanger downstream, which serves for heating of guided in the gas burner combustion air. In particular, a connecting line between the gas turbine and the heat exchanger and between the heat exchanger and the gas burner is provided, so that heat exiting the gas turbine first heats the combustion air and thus the energy released can be supplied to the gas burner again to the combustion process in the gas burner even more efficient. Preferably, the device has an air supply device, which supplies the gas burner, the air, in particular fresh air. The said heat exchanger is arranged in this line

Although there is preferably no direct gas connection between the gas turbine and the gas burner. By means of the heat exchanger, however, thermal energy of the gases emitted by the gas turbine is transferred to other means such as the combustion air, the saturated steam and the hot air and these media are again supplied to the gas burner and / or the gasifier as mentioned above. Furthermore, the gas turbine advantageously acts as a compressor to compress supplied air and to supply the devices for storing thermal energy in turn to be heated cold air, wherein the gas turbine is followed by at least one heat exchanger, which supplies the heated air to the gas burner. In this case, the gas burner is preferably preceded by a carburetor for generating or converting the fuel.

Preferably, further turbine downstream branch means are provided for heating at least one gas. These means are, for example, also heat exchangers, which can simultaneously heat air, so as to produce hot air, which can be supplied to the gasifier. Furthermore, these means saturated steam can be generated, which can also be supplied to the gasifier.

Preferably, at least one of the gas turbine downstream heat exchanger supplied hot air is at least partially supplied as hot exhaust air at least one other heat exchanger and extracted the recovered thermal energy as usable heat. Preferably, at least one of the gas turbine downstream heat exchanger supplied hot air is at least partially supplied as hot exhaust air at least one other heat exchanger, which uses the thermal energy obtained for saturated steam generation.

Preferably, at least one of the gas turbine downstream heat exchanger supplied hot air is at least partially supplied as hot exhaust air at least one further heat exchanger, which uses the thermal energy obtained for hot air generation. Thus, a plurality of heat exchangers are preferably arranged behind one another in a string of the hot air emerging from the turbine.

In this case, a means for alternately switching on at least one first device for storing thermal energy and at least one second device for storing thermal energy in the turbine branch is preferably provided. These alternately switching-on means may, for example, be a multiplicity of controllable valves, which in each case permit the flue gas to be fed alternately into the means for storing thermal energy or allow alternate discharge of heated air to the gas turbine. At least one further heat exchanger arranged downstream of a compressor of the gas turbine is advantageously provided, which at least partially cools supplied hot air and supplies it as cold air to the first and / or second device for storing thermal energy. On the one hand, this is intended to ensure an increase in efficiency of the stored energy. On the other hand, by cooling the air, the temperature of the flue gas can also be reduced.

Further preferably, the compressor of the gas turbine downstream of a

Water injection is provided. Preferably, at least one valve-like means between the compressor and a

Relaxer of the gas turbine provided to turn off the turbine branch. The valve-like means is used for emergency shutdown and is preferably arranged in a bypass between a feed to the expander and a discharge line from the compressor of the gas turbine. Furthermore, temperature sensors can be provided which respectively measure the temperatures at corresponding locations of the devices for storing thermal energy and switch the corresponding valves in response to these measurements, so that optimal supply of the gas turbines with hot air is made possible at all times and furthermore enables efficient recharging of the means for storing thermal energy. An essential advantage of the control of the combustion or gasification process by means of the illustrated arrangement of heat exchangers lies in particular in a very targeted lambda control of the gas burner.

In a further advantageous embodiment of the gas turbine downstream of a steam turbine. Through this downstream steam turbine, the hot air from the first gas turbine can be used once again to generate electricity. Thus, the current efficiency can be further improved.

Advantages and advantages can be found in the following description in conjunction with the drawings. Showing:

Fig. 1 is a first flowchart; and

2 shows a second flowchart.

Fig. 1 shows a schematic flow diagram of the use of a device according to the invention for the conversion of thermal energy from carbonaceous raw materials into mechanical work.

In this case, the reference numeral 1 refers to a gas turbine 8 downstream heat exchanger.

First, the raw material 14 is input from above into the carburetor 18 and the gasification agent (eg air / saturated steam) along a supply line 16 from below. In this way it is achieved that the gasification agent and the product gas flow through the reaction space in the opposite direction to the fuel flow. The resulting ash in the carburetor 18 is discharged downwards, that is, along the arrow P1. The product gas enters the gas burner 2 and is burned. Subsequently, the resulting in the gas burner 2 flue gases are passed through a connecting line 3 and with the help of the valves 46, 44 in a first 4 or second 6 bulk regenerator and supplied by the bulk regenerators 4,6 hot air 7 via a line 21 to a gas turbine 8. In the turbine branch T, a generator G is arranged on the gas turbine 8. The reference numeral 23 denotes a discharge pipe for discharging the flue gas generated in the means 4, 6 for storing thermal energy. From the first regenerator 4 leads a line 22 to the gas turbine 8. The exiting the gas turbine 8 hot exhaust air is supplied via a line 26 to the heat exchanger 1. The heat released is used to heat incoming, compressed air, which is supplied to the gas burner 2 as preheated combustion air 7. The exiting the gas turbine 8 hot exhaust air is then fed to another heat exchanger 13, which serves to generate hot water.

The heat exchanger 13, heat exchangers 1 1, 12 are connected downstream to supply both air and water as a gasifying agent to the fixed-bed countercurrent reactor 18.

The heat exchanger 13 is connected directly downstream of the first heat exchanger 1. By means of this device, it is possible to use the decoupled heat, for example for hot water production at a high temperature level. The heat exchanger 1 1, 12 for heating air and water as a gasifying agent are also downstream of the heat exchanger 13.

The order of the heat exchangers allows precise control of the heat distribution in the process of the invention. The first heat exchanger 1, which receives the combustion air with the highest temperature, is used in particular for generating hot air for the gas burner, the next heat exchanger 13 for generating heat, which is the further heat exchangers 1 1 and 12 is supplied to then hot air or saturated steam produce. Furthermore, it would also be possible to exchange the two heat exchangers 12 and 1 1 with respect to their order. The heat exchanger 15 is connected downstream of the compressor of the gas turbine 8 and cools the compressed hot air emerging from the compressor of the gas turbine 8 and subsequently supplies cold air to the first device 4 and / or second device 6 for storing thermal energy. The temperature efficiency of the stored energy should be increased, but also the temperature of the flue gas should be reduced.

The reference numeral 58 in the figure refers to a pump for conveying water. The reference numeral 10 in the figure refers to the hot air and the reference numeral 9 denotes the saturated steam.

The reference numerals 32, 34, 36, 38, 40, 42, 44, 46 each refer to controllable valves, the supply of the flue gas to the bulk regenerators 4.6 (valves 44 and 46) and the discharge of the hot air of bulk regenerators 4, 6 to the gas turbine 8 (valves 36 and 42), the delivery of flue gas (valves 32 and 38) as well as vice versa the supply of cold air (valves 34 and 40) to the bulk regenerators 4.6 control. The respectively black drawn valves are in an open state and the only rimmed valves in a closed state. Reference numerals 52, 54, 56 respectively refer to compressors for compressing air (reference numeral 56), flue gas (reference numeral 52) and exhaust air (reference numeral 54). Furthermore, air is supplied via the line 25 of the gas turbine 8 and passed through a further heat exchanger 15 to be supplied as cold air in bulk regenerators 4 and 6.

By using the carburetor 18 can advantageously be dispensed with an elaborate dedusting of the flue gases 3.

Fig. 2 shows another embodiment of the present invention. In this embodiment, a further circuit 70 is provided, which is connected downstream of the gas turbine 8. More specifically, the hot air from the gas turbine 8 is passed through a heat exchanger 71, which is integrated in this circuit 70. Through the heat exchanger, water of the circuit 70 is heated and fed to a steam turbine 72, which in turn drives a generator 74. The reference numeral 78 refers to a pump and the reference numeral 76 to a capacitor. By this procedure, the current efficiency of the system can be further increased. All disclosed in the application documents features are claimed as essential to the invention, provided they are new individually or in combination over the prior art.

LIST OF REFERENCE NUMBERS

1 heat exchanger downstream of the gas turbine

2 gas burners

3 flue gases, connecting line

4 First device for storing and dispensing thermal energy

Second means for storing and dispensing thermal energy

7 combustion air, connecting line

8 gas turbine

9 saturated steam

10 hot air

1 1, 12,

13, 15 heat exchangers

14 carbonaceous raw material

16 Supply line for gasification agent

18 carburetors

21, 22 Supply line to the gas turbine

25 line

26 Supply line to heat exchangers

32, 34, 36,

38, 40, 42,

44, 46 controllable valves

52, 54, 56 compressors

58 pump

60 generator

61 Water injection

70 cycle

71 heat exchangers 72 steam turbine

74 generator

76 capacitor

P1 directional arrow

T turbine branch

Claims

claims

1. A method for converting thermal energy from carbonaceous raw materials into mechanical work with at least a first (4) and a second (6) device for storing and dispensing thermal energy, which at least temporarily alternately into a turbine branch (T) with a downstream gas turbine (8) are turned on,

with the following steps:

a) burning a fuel in a gas burner (2), wherein the gas burner combustion air is supplied.

b) passing the flue gases (3) produced in the gas burner (2) through a device (4, 6) for storing thermal energy, and

c) introducing the hot air (7) emitted by at least one device (4, 6) into the gas turbine (8),

characterized in that

from the gas turbine (8) discharged hot air at least one of the gas turbine (8) downstream heat exchanger (1) is supplied and by means of this heat exchanger (1) the gas burner (2) supplied combustion air (7) is heated.

2. The method according to claim 1,

characterized in that

the supplied from the gas turbine (8) and at least one of the gas turbine (8) downstream heat exchanger (1) supplied hot air is at least partially as hot exhaust air at least one further heat exchanger (13) and the extracted thermal energy is decoupled as usable heat.

3. The method according to claim 1,

characterized in that

the hot air discharged from the gas turbine (8) and fed to at least one of the gas turbine (8) at least in part as a hot Exhaust air is supplied to at least one further heat exchanger (1 1) and the recovered thermal energy for the production of saturated steam (9) is used.

4. The method according to claim 1,

characterized in that

the hot air supplied by the gas turbine (8) and fed to at least one of the gas turbine (8) downstream is at least partially supplied as hot exhaust air to at least one further heat exchanger (12) and the thermal energy obtained for the production of hot air (10) is used.

5. Method according to one of the preceding claims,

characterized in that

- In a first step, a gasification of the carbonaceous raw materials (14) in a gasifier (18) takes place and

- The product gas as fuel of the gasifier (1) downstream gas burner

(2) is supplied.

6. The method according to claim 5,

characterized in that

as carburetor (18) a fixed bed countercurrent carburettor (18) is used.

7. The method according to at least one of the preceding claims,

characterized in that

by means of a steam turbine (72) relaxed hot air from the gas turbine (8) is used to generate energy.

8. Device for converting thermal energy into mechanical work, wherein it is provided:

a gas burner (2) for burning a fuel; at least one first (4) and one second (6) device for storing thermal energy, which at least temporarily alternately in a turbine branch (T) with a downstream gas turbine (8) are switched on and at least one connecting line (3) which in the gas burner ( 2) supplying flue gases to the means (4, 6) for storing thermal energy; characterized in that

the gas turbine (8) at least one heat exchanger (1) is connected downstream, which for

Heating of in the gas burner (2) guided combustion air (7) is used.

9. Apparatus according to claim 8,

characterized in that

the gas burner (2) is preceded by a carburetor (1) for generating the fuel.

10. Apparatus according to claim 8 or 9,

characterized in that

further the turbine branch (T) downstream means (1, 1 1, 12,13) are provided for heating at least one gas.

1 1. Device according to at least one of claims 8-10,

characterized in that

At least one of the gas turbine (8) downstream heat exchanger (1) supplied hot air at least partially as hot exhaust air at least one further heat exchanger (13) and the recovered thermal energy can be coupled out as usable heat.

12. Device according to at least one of claims 8-1 1,

characterized in that

At least one of the gas turbine (8) downstream heat exchanger (1) supplied hot air at least partially as hot exhaust at least one other heat exchanger (1 1), which uses the thermal energy obtained for saturated steam generation (9).

13. Device according to at least one of claims 8-12,

characterized in that

at least one of the gas turbine (8) downstream heat exchanger (1) supplied hot air at least partially as hot exhaust air at least one further heat exchanger (12), which receives the thermal energy obtained for hot air generation (10) uses.

14. Device according to at least one of claims 8-13,

characterized in that

a means for alternately switching on at least one first means (4) for storing thermal energy and at least one second means (6) for storing thermal energy in the turbine branch (T) is provided.

15. Device according to at least one of claims 8-14,

characterized in that

at least one further a compressor of the gas turbine (8) downstream heat exchanger (15) is provided, which at least partially cools supplied hot air and as cold air of the first means (4) for storing thermal energy supplies.

16. Device according to at least one of claims 8-15,

characterized in that

the compressor of the gas turbine (8) downstream of a water injection is provided.

17. Device according to at least one of claims 8-16,

characterized in that

at least one valve-like means between the compressor (8) and a gas turbine engine expander for turning off the turbine branch (T) is provided.

18. Device according to at least one of the preceding claims 8 - 17,

characterized in that

the gas turbine (8) is followed by a steam process.