EP2467588A1

EP2467588A1 - Method and device for utilizing biomass

Info

Publication number: EP2467588A1
Application number: EP10745200A
Authority: EP
Inventors: Dragan Stevanovic; Sven Johannssen; Reinhard Pritscher
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: CN102482996B; AU2010285055A1; CA2771145A1; JP5580897B2; AU2010285055B2; UA107196C2; US8621872B2; DE102009038323A1; CN102482996A; JP2013502526A; WO2011020767A1; BR112012003584A2; NZ598329A; EA201290057A1; US20120137702A1

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 at least intermittently alternatingly in a turbine branch (T) having a gas turbine (8) connected downstream thereof, comprising the following steps: a) combusting a gas in a gas burner (2); b) passing the smoke gases (3) arising in the gas burner (2) through a device (4, 6) for storing thermal energy; and c) feeding the hot air (7) released by at least one device (4, 6) into the gas turbine (8), wherein the gasification of the carbonaceous raw materials takes place in a gasifier (1) in a first step and the product gas is fed into the gas burner (2) connected downstream of the gasifier (1).

Description

Method and device for utilization of biomass Description

The invention relates to a method for converting thermal energy from carbonaceous raw materials into mechanical work, according to the preamble of claim 1, and to a device for converting thermal energy into mechanical work, according to the preamble of claim 9. The invention will be 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 formation of dust in the flue gases, which must be removed for example by means of a cyclone.

DE 102 27 074 A1 describes a method for the gasification of biomass and a system for this purpose. In this case, the substances are burned in a gas-tightly separated from a gasification reactor combustion chamber and introduced the heat energy from the combustion chamber in the gasification reactor.

DE 198 36 428 C2 discloses methods and apparatus for gasification of biomass, in particular of wood pulp. In this case, in a first gasification stage, a fixed bed Degassing at temperatures up to 600 ⁰ C and in a downstream second gasification stage, a fluidized bed gasification at temperatures between 800 ⁰ C and 100O ⁰ C.

The present invention is therefore an object of the invention to provide a method and apparatus for converting thermal energy from combustion or gasification of carbonaceous raw materials into mechanical work available, which has a high efficiency and high efficiency while avoiding dust in the Allow flue gases. Furthermore, a method is to be created, which feeds the resulting energies, in particular waste heat, in turn to the process.

This is achieved by a method according to claim 1 and by a device according to claim 9. Advantageous embodiments and further developments are the subject of the dependent claims.

An essential point of the invention is that a method for converting thermal energy from carbonaceous raw materials into mechanical work with at least a first and a second means for storing thermal energy, which are switched at least temporarily alternately in a turbine branch with a downstream gas turbine following Steps:

a) burning a gas in a gas burner,

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

c) introducing the hot air discharged by a device for storing thermal energy into the gas turbine or its expander,

wherein in a first step, a gasification of the carbonaceous raw materials takes place in a gasifier and the product gas is supplied to the gasifier downstream gas burner. The use of a carburettor before the step of combustion in the gas burner enables in particular a significant reduction of dust, in particular fine dust in the flue gases. In addition, a reduced dust content allows the use of higher temperatures during gas combustion. In addition, a higher efficiency in power generation can be achieved. The reduction of fine dust also has a positive effect on the service life of the gas turbine. The term downstream is understood in particular to be a downstream in relation to the respective gases to be processed. Preferably, the gas burner is connected directly downstream of the gasifier. The device for storing thermal energy is preferably also suitable for emitting the stored thermal energy, for example in the form of hot air. Thus, the invention proposes to obtain the product gas for the gas burner from an additional gasification process, so that in this respect no additional dust particles, as in the prior art arise. By switching into the turbine branch is thus understood in particular that the recovered in the means for storing thermal energy hot air is preferably delivered to the gas turbine.

As devices for storing thermal energy in particular bulk generators can be used, as described for example in EP 0 620 909 B1 or the

DE 42 36 619 C2 have been described.

Preferably, heated water vapor or air or a mixture of water vapor and air is introduced into the gasifier as gasification agent 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.

Preferably, a fixed-bed countercurrent carburetor is used as the carburetor. 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.

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 - A - ses 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.

In a preferred embodiment, the waste heat from at least one gasification-following process is used for saturated steam production. This relates in particular to the supply of waste heat to at least one of the gas turbine downstream heat exchanger, is heated with the water. Likewise, a heat exchanger for heating air is provided.

Preferably, the waste heat donating gas is that gas which exits the gas turbine and still has a very high temperature.

In this case, the saturated steam is generated by means of a gas turbine downstream heat exchanger before it is fed to the carburetor.

Cooling is preferably effected by means of at least one heat exchanger and the thermal energy obtained by the cooling is decoupled as usable heat. This further contributes to environmental compatibility and to increasing the efficiency of the process.

Preferably, relaxed hot air from the turbine is re-supplied to the gas burner to further increase the efficiency of the process. For example, combustion air leaving the gas turbine can in turn be supplied to the gas burner via a corresponding supply line. In a further preferred method, relaxed hot air from the gas turbine is used to generate energy by means of another steam turbine. In this case, this additional steam turbine could be integrated into a separate water circuit and the water in this circuit can be vaporized and overheated by a heat exchanger. After exiting the steam turbine, the steam is condensed and compressed in the liquid state by a pump before it passes over the heat exchanger again.

According to the invention for the apparatus for converting thermal energy into mechanical work, a gas burner for burning a fuel, at least a first and a second means for storing thermal energy, which at least temporarily alternately in a turbine branch with a downstream gas turbine or its expander are switched on and at least one connecting line, which supplies flue gases formed in the gas burner to the devices for storing thermal energy, wherein the gas burner is preceded by a carburetor for generating the fuel.

Advantageously, the apparatus comprises a compressor for compressing the air supplied to the devices for storing thermal energy, wherein this compressor is particularly preferably part of the gas turbine.

Thus, it is also proposed on the device side that the flue gases arise during the combustion of a product gas, which in turn is produced in a gasifier. A temporary alternately switching on of the devices for storing thermal energy is understood to mean that at least partially in selected periods of time one of the two devices is supplied with flue gas, while the other device delivers hot air to the gas turbine. Furthermore, it would also be possible for a plurality of devices for storing thermal energy to be provided, which operate at least partially with a time delay. For example, one of these means for storing thermal energy may be supplied with flue gas while one or more of the other devices is releasing the hot air. Also with regard to the delivery of hot air, the devices for storing thermal energy work at least partially delayed.

Preferably, the turbine branch downstream means are provided for cooling a gas. These means for cooling the gas are preferably heat exchangers, which, as mentioned above, 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.

Furthermore, a means for alternately switching at least one first device and at least one second device into 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. Furthermore, temperature sensors can be provided, which respectively measure the temperatures at corresponding points 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 an efficient one Recharging the means for storing thermal energy is enabled.

Furthermore, the gas turbine or a part thereof preferably also acts as a compressor to compress supplied air and to supply cold air to be heated in turn to the devices for storing thermal energy. Particularly preferably, the gas turbine is connected downstream of at least one heat exchanger.

In this case, preferably at least one and preferably a plurality of heat exchangers for decoupling thermal energy is switched on between the gas turbine and the gasifier.

Although there is preferably no direct gas connection between the gas turbine and the gasifier. 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 saturated steam and the hot air and these media are again supplied to the gasifier as mentioned above. Furthermore, a connecting line between the gas turbine and the gas burner is preferably provided, so that in turn exiting the gas turbine combustion air the gas burner can be supplied to make the combustion process in the gas burner even more efficient.

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

Advantages and expediencies can be found in the following description in conjunction with the drawing. Hereby show:

Fig. 1 is a first flowchart; and

Fig. 2 is a second flowchart; and

Fig. 3 is a third 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. The reference numeral 1 refers to a fixed bed countercurrent reactor. The raw material 14 is introduced from above into the reactor 1 and the gasification agent (e.g., air) is fed 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 1 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 in a first 4 or second 6 Schüttgutregenerator 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 from the gas turbine. 8 Exiting exhaust air is supplied via a further line 26 to the gas burner 2 as preheated combustion air. By means of a device not shown here, the first 4 and the second regenerator 6 can be operated alternately in the turbine branch T or in a so-called preheating branch. The reference numeral 60 refers to a generator coupled to the turbine 8.

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 1 can be dispensed with an elaborate dedusting of the flue gases 3.

The reference numeral 61 designates a valve-like means between the compressor and a gas turbine engine expander for turning off the turbine branch. Between the turbine and the heat exchanger 15, a water supply is possible. In this branch, another valve 63 is provided.

In one of the gas turbine 8 leading line 26 heat exchangers 1 1, 12 and 13 are turned on to supply heated both air and water as a gasification agent to the fixed bed countercurrent reactor 1. In addition, a cooling is effected by means of at least one heat exchanger 13 and the thermal energy obtained by the cooling is decoupled as usable heat. In the embodiment shown in FIG. 2, the heat exchanger 13 is directly downstream of the turbine branch T. By means of this device, it is possible to use the decoupled heat (for hot water production) at a higher temperature level. The heat exchanger 1 1, 12 for heating air and water as a gasification agent are connected downstream.

Thus, the order of the heat exchangers is changed in the two embodiments shown. While in the embodiment shown in Figure 1, the first heat exchanger 12, which receives the combustion air with the highest temperature, for generating hot air, the next heat exchanger 1 1 for generating saturated steam and the last heat exchanger 13 for generating heat, is in the shown in Figure 2 with the hottest air generates heat and then hot air or saturated steam. Furthermore, it would also be possible to exchange the two heat exchangers 12 and 1 1 with respect to their order. The reference numeral 58 in the two figures refers to a pump for conveying water. The reference numeral 10 in the figures refers to the combustion gas and the reference numeral 9 designates the saturated steam.

Fig. 3 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 carburetor

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 hot 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

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 blower

58, 78 pump

60 generator

61 valve

63 valve

70 cycle

71 heat exchangers

72 steam turbine

74 generator

76 capacitor

P1 directional arrow

T turbine branch

Claims

claims

A method of converting thermal energy from carbonaceous raw materials into mechanical work having at least first (4) and second (6) means for storing and dispensing thermal energy alternating at least temporarily into a turbine branch (T) with a downstream gas turbine (8) are switched on,

with the following steps:

a) burning a gas in a gas burner (2),

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

- In a first step, a gasification of the carbonaceous raw materials in a gasifier (1) takes place and

- The product gas to the gasifier (1) downstream gas burner (2) is supplied.

2. The method according to claim 1,

characterized in that

heated water vapor (9) and / or air is introduced into the gasifier (1) and used for gasification.

3. The method according to claim 2,

characterized in that

the carburetor (1) together with the water vapor (9) a further gaseous medium as combustion gas (10) is supplied.

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

characterized in that as carburetor (1) a fixed bed countercurrent carburettor (1) is used.

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

characterized in that

the waste heat from at least one of the gasification processes is used for saturated steam production.

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

characterized in that

Saturated steam (9) by means of a gas turbine (8) downstream heat exchanger (11) is generated before it is supplied to the gasifier (1).

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

characterized in that

By means of at least one heat exchanger (13) causes a cooling and the thermal energy obtained by the cooling is decoupled as usable heat.

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

characterized in that

relaxed hot air from the gas turbine (8) the gas burner (2) is supplied again.

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

characterized in that

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

10. 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) resulting flue gases to the facilities (4,6) for storage to supply thermal energy;

characterized in that

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

1 1. Device according to claim 9,

characterized in that

the turbine branch (T) downstream means (1 1, 12, 13) are provided for cooling a gas,

12. Device according to at least one of claims 9 or 10,

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.

13. Device according to claim 9,

characterized in that

the gas turbine (8) at least one heat exchanger (1 1, 12,13) is connected downstream.

14. Device according to claim 9,

characterized in that

between the gas turbine (8) and the carburetor (1) at least one heat exchanger (13) for decoupling thermal energy is switched on.

15. Device according to at least one of the preceding claims 9 - 14,

characterized in that

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