DE102009040227A1 - Method for operating a combined heat and power plant, and cogeneration plant itself - Google Patents

Abstract

The invention relates to a method for operating a block-type thermal power station and the block-type thermal power station itself, according to the preamble of claims 1 and 6. In order to achieve that the effective efficiency in converting heat into electrical energy continues to increase, it is proposed according to the invention that a direct-firing system Piston engine (20) directly or as an internal combustion engine (30) operated primary energy generation process is coupled to a generator (5) for this purpose and that the waste heat generated on the piston engine (20) or on the internal combustion engine (30) through a low-temperature ORC circuit with a Expansion motor (4) is converted, which is mechanically coupled to the same, thus common generator (5).

Description

The invention relates to a method for operating a combined heat and power plant and cogeneration plant itself, according to the preamble of claims 1 and 6.

From the DE 10 2006 043 518 A1 a self-sufficient power generation unit is known in a vehicle, in which the waste heat of the internal combustion engine is used in a Nachverstromungsprozess.

There, as with other known systems of a similar type, it is common for a first generator to be coupled to an internal combustion engine on the primary high temperature utilization side, and a second generator to be coupled to the turbine of a waste heat recovery process, such as an ORC process.

As a result, this means that two generators are necessary. This is detrimental in terms of efficiency.

The invention is therefore based on the object to further develop a method and a device of the generic type such that the effective efficiency in the conversion of heat into electrical energy continues to increase.

With regard to a method of the generic type, the object is achieved by the features of claim 1.

Advantageous embodiments of the method are specified in the remaining dependent claims 2 to 6.

With respect to the device or the system of the generic type, the object is achieved by the features of claim 7.

Further advantageous embodiments of the device or the system are specified in the remaining dependent claims.

The core of the method according to the invention is that a directly driven by direct firing piston engine or primary combustion power plant primary power generation process is coupled thereto with a generator, and that the resulting on the piston engine or on the internal combustion engine waste heat is converted by a low-temperature ORC cycle with a relaxation motor , which is mechanically coupled to the same, thus common generator.

As a result, there are two energy conversion processes.

The first energy conversion process converts the direct combustion or process heat into mechanical energy, and the second energy conversion process also converts the low temperature waste heat of the first energy conversion process into mechanical energy. Both energy components from the first and second process are now synchonized by means of a transfer or reduction of Drehbegwegungen so that they drive a common generator.

Thus, a common generator is driven with these two energy conversion processes.

Result. Compared with known arrangements with main heat and waste heat from the generation of two generators, but only one generator must be operated.

In an advantageous embodiment, it is provided that the coupling to the common generator is decoupled during the start of the power generation processes until both processes have started. This is to prevent that in the start-up phase, the engine is braked in the high-temperature range by the low-temperature (ORC) range engine coupled via the generator.

Until both processes have started, they will be decoupled from each other. After the start of both processes then takes place the mechanical coupling to the common generator.

In an advantageous embodiment, it is provided that the low-temperature waste heat of the primary power generation process is the waste heat of one or more coolers and / or the exhaust heat.

It is advantageously provided that the low-temperature waste heat of the primary energy-generating process is the waste heat from one or more coolers.

In a further advantageous manner, it is stated that the coolers are thermally coupled via heat exchangers with the ORC working medium, or its evaporator.

The said speed synchronization takes place by tuning via a speed monitoring of the generator speed, mechanical transmission or transmission / reduction means between the first engine and the second engine or expansion engine.

In a further advantageous embodiment, it is provided that the transmission or reduction between the rotational speed of the first engine and the expansion engine is set so that the mechanical if necessary. Over- or under-setting connection of both force (torque) sources leads to a rotational MOMENTerhöhung the common generator.

With respect to a combined heat and power plant itself, the gist of the invention is that the waste heat of an engine, in particular due to radiator, can be supplied to an evaporator of an ORC cycle arranged on or in the CHP, and the relaxation machine of the ORC cycle is mechanically coupled to the same generator of the CHP is.

In an advantageous embodiment, it is provided that the generator speed can be detected via speed detection means, and an automatic control device can be controlled by way of which the mechanical transmission or transmission / reduction means between the first engine and the expansion engine are automatically tuned.

The economic feasibility and the optimization of the overall efficiency requires that both engines of the first and the second energy conversion process BOTE run at a relatively low speed, so that the mechanical transmission or reduction is less expensive.

This is achieved by said embodiments in that both machines are prime movers, preferably piston engines. A mechanical coupling of a piston engine with a high-speed turbine would be rather difficult or uneconomical.

Thus, the choice of machine category for the first and second power generation processes is also of considerable importance. This is therefore important in order to gain a significant effect on the overall efficiency increase of waste heat generation.

In a further advantageous embodiment, it is provided that the speed detection means is designed as a measuring shaft on the generator shaft encoder.

This is easy, eg. With optical encoders possible.

Alternatively, it can also be provided that the speed detection means are implemented in the control device, which determine the current speed via the induction curve of the generator.

Furthermore, it is advantageously designed such that the transfer / reduction means are controllable, a quasi-synchronized rotational speed is set between the rotational speeds of the rotational axes or rotational shafts of the engines and the expansion engine and the generator shaft.

Advantageously, it is provided that the over / under setting means contain freewheeling means which decouple the associated power machines from the generator until the start of primary and secondary energy generation processes. This in order to realize the effect already described above in the method, namely, that the said engines remain decoupled until the processes have started.

In a simple way, these freewheeling means may be a clutch.

An embodiment of the invention is illustrated in the drawing and explained in more detail below.

It shows:

The figure shows a schematic representation of the inventive coupling of mechanical energy from the primary, in the CHP (combined heat and power plant) 1 generated process. This is about a rotary shaft, with a in the CHP 1 arranged engine 20 . 30 connected is driven and the generator 5 fed.

The piston engine or the internal combustion engine 20 respectively. 30 are inside the CHP 1 integrated and therefore not separately visible, or shown.

The waste heat from this direct process becomes a cooler 2 fed, ie the cooler 2 leads exactly this waste heat.

Except the illustrated cooler 2 can also the exhaust heat of the machines 20 and 30 still be used, which then also the ORC cycle 3 would be fed. This is thus an evaporator of an ORC cycle 3 fed.

The organic medium of this ORC cycle operates a relaxation engine 4 , The wave of the relaxation motor is about over or reducing means, for example. A transmission 6 mechanically to the output shaft of the engine 20 . 30 of the CHP 1 coupled. This ultimately generates an increase in torque on the associated shaft of the generator 5 ,

This said generator shaft is automatically detected in its speed via optical or mechanical, or inductive speed detection means.

The gear 6 In this case also integrally contains a clutch, with which the coupling of the two rotary shafts of the engine 20 . 30 and relaxation engine 4 can be temporarily disconnected until both processes, ie high-temperature process and low-temperature process have started.

The detected rotational speed is in a control device 7 fed in, and there are control signals for the automatic adaptation of the transmission / reduction means (transmission). 6 determined and on the transmission, if necessary. Also controlled the clutch. This then causes a speed synchronization of the relaxation engine and the engine 20 . 30 each fed torque.

In this way, one and the same generator is used for the main power generation and the power conversion 5 used.

The use of an otherwise customary second generator is completely eliminated.

Thus, the achievable overall efficiency increases considerably.

LIST OF REFERENCE NUMBERS

1

CHP with internal combustion engine 30 , or piston engine 20

2

Heat exchanger / cooler

3

ORC cycle

4

expansion engine

5

generator

6

Over- / reduction means / transmission

7

control device

8th

Tachometer

9

clutch

20

Reciprocating engine

30

Internal combustion engine

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006043518 A1 [0002]

Claims (13)

Method Operation of a combined heat and power plant (CHP), in particular in the case of direct firing of biomass or biomass energy sources, such as biogas or biofluid fuel, or biomass solids, and with at least one engine-generator arrangement, characterized in that a piston engine operated by direct firing ( 20 ) directly or as an internal combustion engine ( 30 ) operated primary power generation process for this purpose with a generator ( 5 ), and that on the piston engine ( 20 ) or on the internal combustion engine ( 30 ) waste heat through a low-temperature ORC circuit with a relaxation motor ( 4 ), which mechanically to the same, thus common generator ( 5 ) is coupled. A method according to claim 1, characterized in that the coupling to the common generator is decoupled during startup of the power generation processes until both processes have started. A method according to claim 1 or 2, characterized in that the low-temperature waste heat of the primary power generation process, the waste heat from one or more coolers and / or the exhaust heat A method according to claim 3, characterized in that the cooler via heat exchangers with the ORC working medium, or its evaporator, are thermally coupled. Method according to one of claims 1 to 4, characterized in that via a speed monitoring of the generator speed, mechanical transmission or transfer / reduction means between the first and engine ( 20 . 30 ) and the relaxation engine ( 4 ). Method according to one of the preceding claims, characterized in that between the rotational speed of the first engine ( 20 . 30 ) and the relaxation engine ( 4 ) is set so that the mechanically possibly over or under-setting connection of both force (torque) sources to a rotational MOMENTerhöhung the common generator ( 5 ) leads. Combined heat and power plant (CHP), in particular in direct firing of biomass or biomass energy sources, such as biogas or biofluid fuel, or biomass solids, and with at least one engine-generator arrangement, characterized in that in particular by cooler ( 2 ) waste heat of an engine ( 20 . 30 ) arranged on or in the CHP evaporator an ORC cycle ( 3 ), and that the expansion machine ( 4 ) of the ORC circuit mechanically to the same generator ( 5 ) of the CHP ( 1 ) is coupled. Cogeneration plant according to claim 6, characterized in that via speed detection means ( 8th ) the generator speed is detectable, and via an automatic control device ( 7 ) is controllable, via which the mechanical transmission or transmission / reduction means between the engine ( 20 . 30 ) and the relaxation engine ( 4 ) are automatically tunable. Cogeneration plant according to claim 7, characterized in that the speed detection means ( 8th ) at the generator shaft and / or at the rotary shafts of the engines ( 20 . 30 ) and the Enspanngmotors ( 4 ) Measuring encoder is designed. Cogeneration plant according to claim 7, characterized in that the speed detection means ( 8th ) in the control device ( 7 ) are implemented, which via the induction curve of the generator ( 5 ) determine the current speed. Cogeneration plant according to one of the preceding claims, characterized in that the transfer / reduction means ( 6 ) are so controlled, between the rotational speeds of the rotary axes or rotary shafts of the engine ( 20 . 30 ) and the relaxation engine ( 4 ) and the generator shaft is set to a quasi-synchronized speed. Cogeneration plant according to one of the preceding claims, characterized in that the over / under setting means ( 6 ) Freewheeling means ( 9 ), which, until the start of the primary and secondary energy generation process, 20 . 30 . 4 ) decouple from the generator. Cogeneration plant according to claim 12, characterized in that the freewheeling means a coupling ( 9 ).

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