DEVICE FOR GENERATING COMBUSTIBLE PRODUCT GAS FROM CARBONACEOUS FEEDSTOCKS

Abstract

A device is provided for generating combustible product gas from carbonaceous feedstocks through allothermal steam gasification in a pressurized gasification vessel. The pressurized allothermal steam gasification of carbonaceous fuels requires that heat be supplied to the gasification chamber at a temperature level of approximately 800-900° C. In a heat pipe reformer, as is known from EP 1 187 892 B1, combustible gas is generated from the carbonaceous feedstocks to be gasified through allothermal steam gasification in a pressurized fluidized bed gasification chamber. The heat needed for this is fed to the gasifier or reformer from a fluidized bed combustion system through a heat pipe arrangement. Due to the straight and tubular construction of heat pipes, the combustion chamber and reformer/gasification chamber are disposed one above the other in the known heat pipe reformer from EP 1 187 892 B1. The pressure vessel base is under particular stresses due to the high temperatures in the combustion chamber. In addition, the base is weakened by a plurality of heat pipe feedthroughs. The sealing of the feedthroughs also presents a problem. In conventional tubular heat pipes, the line for liquid heat transfer medium and for gaseous heat transfer medium are both disposed in the common tubular shell. The fact that the present invention uses loop heat pipes in which the liquid heat transfer medium is conveyed spatially separated from the gaseous heat transfer medium allows the number of feedthroughs to be reduced to two, namely a liquid line and a vapor line. When a plurality of such loop heat pipes is used, the separate vapor and fluid lines thereof can be combined in the

Description

The invention relates to a device for generating combustible product gas from carbonaceous feedstocks through allothermal steam gasification in accordance with the preamble of claim 1.

The pressurized allothermal steam gasification of carbonaceous fuels requires to supply heat on a temperature level of approx. 800-900° C. into the gasification chamber. In the so-called heat pipe reformer as known from EP 1 187 892 B1, fuel gas is produced from the carbonaceous feedstocks to be gasified in a pressurized fluidized bed gasification chamber through allothermal steam gasification. The heat required for this purpose is conducted from a fluidized bed combustion system into the gasifier or reformer by means of a thermoconducting pipe arrangement. Due to the straight and tubular construction of heat pipes, the combustion chamber and the reformer/gasification chamber are disposed one above the other in the heat pipe reformer known from EP 1 187 892 B1. The pressure vessel base is subject to particular stresses due to the high temperatures in the combustion chamber. In addition, the base is weakened by a plurality of heat pipe feedthroughs. Sealing of the feedthroughs also presents a problem.

Under the named operating conditions, hydrogen diffuses through the metal jacket of the heat pipes to the inside of the heat pipe and gathers in the area of the condenser, or heat-releasing side. Heat transfer ceases to take place in the area of this hydrogen pocket, whereby the thermal energy transferred by the heat pipe is reduced. In order to avoid such hydrogen pockets, it is known to prevent or reduce the diffusion of hydrogen with the aid of coatings of the heat pipes or by separating gasification and heat transition zones inside the gasifier. In accordance with a different approach, the outward diffusion of hydrogen is intensified by an increased internal pressure and flushing caps. In this regard, reference is made to DE 102006016005 A1.

Starting out from EP 1 187 892 A1 it is the object of the present invention to reduce the weakening of the gasifier pressure vessel through the heat pipe feedthroughs.

This object is achieved through the features of claim 1.

In traditional, tubular heat pipes the lines for both the liquid heat transfer medium and also for the vaporous heat transfer medium are disposed in the common tube shell. Due to the fact that the present invention employs loop heat pipes where the liquid heat transfer medium is conducted in physical separation from the vaporous heat transfer medium, the number of feedthroughs may be reduced to two, namely, a liquid line and a steam line. When a plurality of such loop heat pipes is employed, their separately routed steam and liquid lines may be combined inside the gasifier pressure vessel into one common steam line and liquid line which are then passed through the gasifier pressure vessel. Outside of the gasifier pressure vessel the two common lines may then be split again. The number of feedthroughs from and into the gasifier pressure vessel may thus be reduced considerably, to a minimum of two.

Another advantage of the invention resides in the fact that the physical separation of steam and liquid lines of loop heat pipes allows for a higher freedom of design. Gasifier or reformer, respectively, and external heat source may be disposed and optimized entirely independently of each other.

Due to the separate routing of steam and liquid line, the course of the steam line may be optimized with a view to the arrangement of a hydrogen separating means—claim 2.

The advantageous aspects of claims 3 and 4 relate to different construction forms for loop heat pipes with a separately realized steam and liquid line.

In accordance with the advantageous aspect of the invention according to claim 5, the heat transfer from the external heat source into the gasifier takes place through two physically separated heat medium circuits with phase change which are connected in series. In this way the first heat medium circuit or the associated heat pipe, respectively, may be optimized with regard to heat absorption inside the heat source, while the second heat medium circuit or the associated heat pipe, respectively, may be optimized with regard to heat release inside the gasifier.

Loop heat pipes with separately configured steam and liquid lines for the first stage for absorbing the heat in the heat source and pulsed loop heat pipes having common steam/liquid lines have been found to be a particularly suitable combination for releasing the heat in the gasifier—claims 6 and 7.

Due to the advantageous aspect of the invention according to claim 10, on the one hand the pyrolysis residues from the gasifier are utilized thermally, and on the other hand the entire fuel supply may thus take place in the fluidized bed combustion chamber. An additional supply of fuel into the fluidized bed combustion chamber is not necessary any more, with the exception of the start-up.

Due to the high operation temperatures, alkali metals and their alloys, e.g. Na, K, NaK, are particularly well suited as a heat transfer medium in the loop heat pipes.

The remaining subclaims relate to further advantageous aspects of the invention.

Further details, features and advantages result from the following description of preferred embodiments making reference to the drawings, wherein:

FIG. 1 shows the basic structure of a Highterm reformer in accordance with the present invention;

FIG. 2 is a schematic representation of a first embodiment of the invention in the Highterm reformer;

FIG. 3 is a first embodiment of the high-temperature heat medium circuit in the Highterm reformer having the form of a loop heat pipe pulsed by means of a capillary structure (capillary pumped loop heat pipe), CPL;

FIG. 4 is a second embodiment of the high-temperature heat medium circuit having the form of a loop heat pipe, LHP;

FIG. 5 shows the pressure-temperature state diagram for the LHP according to FIG. 4;

FIG. 6 is a second embodiment of the Highterm reformer of the present invention including two physically separated heat medium circuits;

FIG. 7 shows a pulsed loop heat pipe (Closed Loop Pulsating Heat Pipe; CLPHP) as used in the Highterm reformer according to FIG. 7 as a second heat medium circuit;

FIG. 8 shows an exemplary aspect of the hydrogen separating means of the Highterm reformer;

FIG. 9 shows a third embodiment of the Highterm reformer according to the present invention, with gasifier and combustion chamber in a common vessel; and

FIG. 10 shows a third embodiment of the high-temperature heat medium circuit having the form of immersed loop heat pipes.

FIG. 1 shows the basic structure of a Highterm reformer according to the present invention. The Highterm reformer includes a pressurized gasifier or reformer 2 and an external heat source having the form of a combustion chamber 4. The gasifier 2 includes a gasifier pressure vessel 6, a fuel supply means 8, a water or steam supply 10, and a product gas extracting line 12. At a temperature of 800° C. to 900° C., product gas is produced in a manner known per se through allothermal steam gasification from carbonaceous fuels. The gasifier 2 and the external heat source 4 are connected to each other through a heat medium circuit or a loop heat pipe 14, respectively. The heat medium circuit or loop heat pipe 14 has a heat-absorbing side 16 and a heat-releasing side 18 which are connected to each other through a steam line 20 for vaporous heat transfer medium and a liquid line 22 for liquid heat transfer medium. Via a material lock 24 the gasifier 2 is connected to the heat source 4. Via the material lock 24 pyrolysis residues from the gasifier 2 are supplied to the combustion chamber 4 as fuel. The combustion chamber 4 furthermore comprises an air supply 26 and a flue gas outlet 28. In the liquid line 22 a hydrogen separating means 30 is arranged between gasifier 2 and combustion chamber 4.

As a result of the combustion of the pyrolysis residues from the gasifier 2 and/or through combustion of additional fuel, heat is generated in the combustion chamber 4 which is absorbed through the heat-absorbing side 16 of the loop heat pipe 14 due to that the fact that the liquid heat transfer medium supplied via the liquid line 22 evaporates. The vaporous heat transfer medium flows into the gasifier via the steam line 20, condenses in the heat-releasing side 18 of the loop heat pipe 14, and thus furnishes the high-temperature heat required for the allothermal steam gasification. The liquefied heat transfer medium is supplied via the liquid line 22, together with the hydrogen having diffused into heat medium circuit 14 in the gasifier, to the hydrogen separating means 30. By means of the hydrogen separating means 30 the hydrogen as well as other foreign matter is separated from the liquid heat transfer medium while the remaining liquid heat transfer medium is resupplied to the combustion chamber 4, whereby the heat transfer medium circuit is closed. Owing to the high temperatures, alkali metals or alloys of these, e.g. Na, K, or NaK, are used.

FIG. 2 schematically shows a first, concrete embodiment of the invention, wherein same reference numerals are used for analogous components. The combustion chamber 4 is a fluidized bed combustion chamber including a circulating fluidized bed 32. The combustion chamber 4 includes an ascending pipe 34, a cyclone 36, as well as a material lock 38 and a fluidized bed 40 which lead back into the ascending pipe 34. The heat-absorbing side 16 of the loop heat pipe 14 includes a first and a second pipe bundle heat exchanger 42 and 44 which are connected in series and in which the liquid heat transfer medium is evaporated through the absorption of heat. The heat-releasing side 18 includes a third pipe bundle heat exchanger 46 in which the vaporous heat exchanger medium condenses again by releasing the previously absorbed heat.

In the embodiment according to FIG. 2, there is no restriction in terms of design and operating method for the combustion chamber 4 as compared with the so-called heat pipe reformer according to EP 1 187 892 A1. All of the constructive and operational parameters may thus be adapted optimally to the requirements of providing high-temperature heat. Utilization of the circulating fluidized bed 32 has the advantage of optimum combustion in the ascending pipe 34 and optimum, material-friendly heat extraction from the fluidized bed 40—first pipe bundle heat exchanger 42—and via membrane walls—second pipe bundle heat exchanger 44—in the turbulent base zone of the ascending pipe 34. As regards the specific construction of the combustion chamber 4 having a circulating fluidized bed 32, reference is made to “Handbook of Fluidization and Fluid-Particle Systems” by Wen-Ching Yang, ISBN: 0-8247-0259-X.

The reformer or gasifier 2 may equally be designed without any restrictions in terms of the combustion chamber 4 because combustion chamber 4 and gasifier 2 are not disposed in a common vessel as in the heat pipe reformer. The feedthrough of high-temperature steam line and liquid line 20, 22 is placed in constructively favorable locations of the gasifier pressure vessel 6. In the embodiment according to FIG. 2, the liquid line 22 and the steam line 20 are led out laterally from the barrel-shaped gasifier 2. Lid and base of the gasifier pressure vessel 6 are free from the multiplicity of heat pipe feedthroughs as known from the heat pipe reformer. The only existing weakenings are due to the steam supply 10 and the fuel supply 8, as well as product gas extracting line 12 and material lock 24 for discharging pyrolysis residues.

Owing to an internal thermal insulation of the gasifier pressure vessel 6, the reaction temperature in the gasifier may be substantially higher than the temperatures at the wall of the gasifier pressure vessel. As a result, stable constructions are realized even with the use of lower-cost materials having lower wall thicknesses.

The pyrolysis residues of the gasifier 2 may be utilized directly in the combustion chamber 4 via the material lock 24. At a favorable process management, the pyrolysis residues are sufficient to cover the fuel demand of the combustion chamber 4. Product gas leakage flows via the material lock 24 may be burnt off safely and completely in the combustion chamber 4.

FIG. 3 shows a first embodiment of the high-temperature heat medium circuit in the Highterm reformer having the form of a capillary pumped loop heat pipe (CPL) 500 as known from the publication “Heat Pipe Science and Technology”, Amir Fahgri, 1995, page 583. The CPL 500 includes a heat-absorbing side or an evaporator 516, respectively, and a heat-releasing side or condenser 518, respectively. Evaporator 516 and condenser 518 are connected to each other via a steam collection line 520 for vaporous heat transfer medium and a liquid collection line 522 for liquid heat transfer medium. Steam collection line 520 and liquid collection line 522 are configured physically separate from each other. Both the evaporator 516 and the condenser 518 consist of several identical evaporator elements 524 and condenser elements 526 which are arranged in parallel. The evaporator elements 524 present a capillary structure 528 whereby liquid heat transfer medium is evaporated through heat absorption. In the condenser elements 526 the heat transfer medium condenses again while releasing heat.

The liquid collection line 522 is connected to a compensation vessel 532 via a compensation line 530. The compensation vessel 532 ensures a uniform filling level in the liquid collection line 522. As a result of a slight temperature gradient and thus also a pressure gradient, the liquid heat transfer medium flows back into the liquid collection line 522. The evaporation enthalpy absorbed in the evaporator 516 (combustion chamber 4) thus is released again in the condenser 518 (gasifier 2).

The hydrogen separating means is integrated into the liquid collection line 522 (not represented in FIG. 3).

FIG. 4 shows a second embodiment of the high-temperature heat medium circuit in the Highterm reformer which has the form of a loop heat pipe (LHP) 600 as known from the publication “Heat Pipe Science and Technology”, Amir Fahgri, 1995, page 586. The LHP 600 includes a heat-absorbing side or an evaporator 616, respectively, and a heat-releasing side or a condenser 618, respectively. Evaporator 616 and condenser 618 are connected to each other via a steam line 620 for vaporous heat transfer medium and a liquid line 622 for liquid heat transfer medium. Steam line 620 and liquid line 622 are configured physically separate from each other. In the evaporator 616 a capillary structure 628 is disposed whereby liquid heat transfer medium is evaporated through absorption of heat. In the condenser 618 the heat transfer medium condenses again while releasing heat.

In state 1—FIG. 5—the heat transfer medium is in liquid/steam equilibrium (f-d-GGW), and in state 2 it is superheated in the evaporator 616. From state 2 to 3 the pressure drops owing to flow losses. State 3 via 4 to 5 shows the complete condensation, including supercooling, of the condensate (state 5). In state 6 the heat transfer medium is located in the upper range of the evaporator 616 and is heated to state 7 by the evaporator 616 (f-d-GGW), to then be superheated to the temperature 8 in the lower range of the evaporator 616. In order for the LHP 600 to function in accordance with its intended purpose, it is necessary that the capillary pressure difference in the capillary structure 628 is greater than the sum of pressure losses of the steam and liquid flows, the capillary structure 628, and the hydrostatic pressure. I.e., the required condition is:

(Δp_cap)_max≧Δp_u+Δp_e+Δp_w+Δp_g

Such a loop heat pipe is also known from WO/2003/054469.

FIG. 6 shows a second embodiment of the Highterm reformer according to the present invention, comprising a two-stage high-temperature heat medium circuit 700. The high-temperature heat medium circuit 700 includes a primary heat medium circuit 701 and a secondary heat medium circuit 702. The primary heat medium circuit 701 includes a heat-absorbing side 716 and a heat-releasing side 718. The heat-absorbing side 716 and the heat-releasing side 718 are connected to each other through a steam line 720 for vaporous heat transfer medium and a liquid line 722 for liquid heat transfer medium. Steam line 720 and liquid line 722 are configured physically separate from each other. The heat-releasing side 716 is arranged inside the combustion chamber, and the heat-releasing side 718 is arranged inside the gasifier. The primary heat medium circuit 701 may be realized by means of the loop heat pipes 500 and/or 600 in FIGS. 3 and 4.

The secondary heat medium circuit 702 is realized with the aid of a pulsed loop heat pipe (Closed Loop Pulsating Heat Pipe, CLPHP) as represented in FIG. 7. The CLPHP 702 has a heat-absorbing side 736 and a heat-releasing side 738. The heat-absorbing side 736 and the heat-releasing side 738 are connected to each other through a closed, meander-type steam/liquid line 740. Both the heat-absorbing side 736 and the heat-releasing side of the CLPHP 702 are arranged inside the gasifier pressure vessel 706. The heat-absorbing side 736 of the CLPHP 702 is integrated into the heat-releasing side 718 of the primary heat medium circuit 701.

In the closed condition of the pulsed loop heat pipe 702, the heat transfer medium is alternately conducted via the steam/liquid line 740 from the evaporator 736 into the condenser 738. A temperature difference brings about a pressure difference causing a pulsed flow in the whole system. As a result it is possible to transport off hydrogen pockets and other inert gases by convection, to withdraw these in a suitable location, e.g. at the top of the condenser 738 via a gas vent 730.

In the following, an exemplary embodiment of a hydrogen separating means or gas venting means 30, 730, 830 is described with reference to FIG. 8. One advantage of the dual heat medium circuit resides in the fact that due to the pulsating secondary heat transfer medium circuit being uncoupled from the combustion chamber 4, less heat transfer medium may leak out in the event of leakages.

Due to manufacturing conditions, inert gas may be present in the alkali-liquid-steam circuit. During operation, hydrogen diffuses into the circuit. The consequences of an accumulation of inert gases in the system are manifold and have varying degrees of effect depending on the circuit system (CPL, LHP, . . . ):

• • Accumulations of inert gases may detract from operation in accordance with the intended purpose. For example, inert gas accumulations in tube bends cause an interruption of flow and thus an interruption in heat transfer. Local overheating in the evaporator part might ensue.
  • Permanent inward diffusion of hydrogen results in a rising overall pressure in the system. Depending on the type of system, this might also influence the vapor pressure of alkali metal and thus the evaporation temperature. It might be possible to influence the evaporation temperature of the alkali metal circuit with the aid of a gas venting device.

The gas venting device or hydrogen separating means 30 for an alkali metal liquid-steam circuit accordingly has to satisfy the following marginal conditions:

• • 1. Mountings that are in contact with the media must be resistant against alkali metals, hydrogen, and in a given case alkali hydroxide (lyes). Moreover the mountings must be temperature-resistant.
  • 2. Cutoff mountings and (pressure reducing) valves must be vacuum-tight over a large temperature range.
  • 3. The gas venting device must safely prevent outward transfer of heat transfer medium (alkali metal). A reliable gas-liquid separation must therefore be ensured. Accordingly it is also necessary to provide a condensate discharge line.
  • 4. Solidification of the heat transfer medium in the gas venting area must be avoided in accordance with the type of heat transfer medium used.

FIG. 8 shows an exemplary structure of the hydrogen separating means 30 that is appropriate for use in the various embodiments of the Highterm reformer. The hydrogen separating means 30 in the liquid line 22, 522, 622, 722 includes a collecting vessel 300 having a liquid level adjusted. The collecting vessel 300 includes a gas dome 302 in which vaporous heat transfer medium is present and in which hydrogen and other inert gases accumulate. From this gas dome 302 a tap line 304 branches off which leads into a range of lower temperatures and terminates in a lock means 306. Accordingly it is possible to use materials such as, e.g., EPDM (Ethylene Propylene Diene Monomer) (up to approx. 150° C.) etc. for the valves 308, 310, 312, 314. The temperature of the tap line 304 is crucial for the vapor pressure of the heat transfer medium. A long tap line 304 thus results in a separation of inert gas and heat transfer medium. The temperature of the tap line 304 must not be lower than the solidification temperature of the heat transfer medium in order to keep the tap line 304 from being blocked.

Gas venting allows for pressure regulation and thus also temperature regulation. As was already mentioned, the pressure sensitivity of the system is highly dependent on the circuit system.

The lock means 306 leading to the gas vent consists of four valves 308, 310, 312, 314 with respective serial arrangement of the first and second valves 308, 310 and of the third and fourth valves 312, 314, and parallel arrangement of the two serial pairs 308, 310 and 312, 314. The parallel connection results in a redundancy lock system. If possible, the gas vent system or the hydrogen separating means 30 should be installed in the coolest location of the heat medium circuit. While valve 308 or 312 is closed and valve 310 or 314 is open, a vacuum pump—not represented—creates a vacuum, after which valve 310 or 314 is closed and valve 308 or 312 is opened and closed again.

Subsequently this cycle begins anew. In this way, hydrogen and other inert gases are discharged from the heat medium circuit.

FIG. 9 shows a third embodiment of the Highterm reformer comprising a fluidized bed combustion chamber 804 and a gasifier or reformer 802. The gasifier 802 includes a gasifier pressure vessel 806 disposed, together with the fluidized bed combustion chamber 804, in a common reactor vessel 805. As a high-temperature thermal circuit for transfer of the heat from the fluidized bed combustion chamber 802 into the gasifier 804 a loop heat pipe means 814 having a plurality of loop heat pipes in accordance with FIGS. 3 and 4 is employed. The plurality of loop heat pipes are composed to form an evaporator group 816 and a condenser group 818. Condenser group 818 and evaporator group 816 are connected to each other via a single steam line 820 and via a single liquid line 822. The evaporator group 816 is disposed in the fluidized bed combustion chamber 804, and the condenser group 818 in the gasifier pressure vessel 805. Hydrogen and other inert gases are withdrawn via a gas venting and charging pipe 830 leading out from the condenser group 818, from the gasifier pressure vessel 806 and from the common reactor vessel 805. At the same time, charging of the loop heat pipe means 814 with heat transfer medium takes place via the gas venting and charging pipe 830. The advantage of this third embodiment of the invention resides in the fact that the loop heat pipe means 814 may be integrated into a previously existing reactor design.

FIG. 10 shows an alternative aspect of a heat pipe having the form of a so-called immersed heat pipe 900. The immersed heat pipe 900 consists of an outer pipe 902 having an open end 904 and a closed end 906. Inside the outer pipe 902 an inner pipe 908 is disposed which has a first open end 910 and a second open end 912 to be open on both sides. Vaporous heat transfer medium flows in via the open end 904 of the outer pipe 902 and condenses on its downward way to the closed end 906 of the outer pipe 902. The condensed heat transfer medium flows upward again through the first open end 910 of the inner pipe 908 and is discharged from the immersed heat pipe 900 via the second open end 912 of the inner pipe 908. A corresponding pressure gradient is necessary to again convey the heat transfer medium condensate in an upward direction. The supply of vaporous heat transfer medium via the open end 904 of the outer pipe 902 and the discharge of the liquid heat transfer mediums via the second open end 912 of the inner pipe takes place transversely to the longitudinal extension of outer and inner pipes 902, 908.

The immersed heat pipe 900 described in the foregoing allows to avoid meander-type heat transfer medium pipe layouts which constitute a problem in fluidized beds, in particular in the gasifier, as they interfere with build-up and layer formation of the fluidized bed.

LIST OF REFERENCE NUMERALS

2 pressurized gasifier or reformer

4 heat source or combustion chamber

6 gasifier pressure vessel

8 fuel supply means

10 water or steam supply

12 product gas extracting line

14 high-temperature heat medium circuit or loop heat pipe

16 heat-absorbing side of 14

18 heat-releasing side of 14

20 steam line

22 liquid line

24 material lock for pyrolysis residues

26 air supply

28 flue gas outlet

30 hydrogen separating means

32 circulating fluidized bed

34 ascending pipe

36 cyclone

38 material lock

40 fluidized bed

42 first pipe bundle heat exchanger

44 second pipe bundle heat exchanger

46 third pipe bundle heat exchanger

300 collecting vessel of 30

302 gas dome

304 tap line

306 lock means

308 first valve

310 second valve

312 third valve

314 fourth valve

500 capillary pumped loop heat pipe

516 heat-absorbing side or evaporator of 500

518 heat-releasing side or condenser of 500

520 steam collection line

522 liquid collection line

524 evaporator element

526 condenser element

528 capillary structure of 524

530 compensation line

532 compensation vessel

600 loop heat pipe, LHP

616 heat-absorbing side or evaporator of 600

618 heat-releasing side or condenser of 600

620 steam line

622 liquid line

628 capillary structure of 616

700 two-stage high-temperature heat medium circuit

701 primary heat medium circuit

702 secondary heat medium circuit, pulsed loop heat pipe, CLPHP

706 gasifier pressure vessel

716 heat-absorbing side of 701

718 heat-releasing side of 701

720 steam line

722 liquid line

730 gas venting means

736 heat-absorbing side or evaporator of 702

738 heat-releasing side or condenser of 702

740 steam/liquid line

802 gasifier or reformer

804 fluidized bed combustion chamber

805 common reactor vessel

806 gasifier pressure vessel

814 loop heat pipe means

816 evaporator group

818 condenser group

820 steam line

822 condensate line

830 gas venting and charging pipe

900 immersed heat pipe

902 outer pipe

904 open end of 902

906 closed end of 902

908 inner pipe

910 first open end of 908

912 second open end of 908

Claims

1. A device for generating combustible product gas from carbonaceous feedstocks through allothermal steam gasification, comprising:

a pressurized gasifier including a gasifier pressure vessel, a supply means for the carbonaceous feedstocks, a steam supply, and a product gas extracting line,

an external heat source, and

a heat transport means comprising at least one heat pipe whereby heat is transported, with the aid of a heat transfer medium undergoing a phase change, from the external heat source into the gasifier,

wherein the at least one heat pipe has a heat-releasing side disposed inside the gasifier and a heat-absorbing side disposed inside the external heat source, and

wherein the at least one heat pipe is a loop heat pipe, the heat-absorbing and the heat-releasing side of which are connected to each other via a liquid line for liquid heat transfer medium and via a steam line for vaporous heat transfer medium, and in that the liquid line and the steam line are physically separate lines.

2. The device according to claim 1, wherein a hydrogen separating means is disposed in the liquid line of the at least one loop heat pipe.

3. The device according to claim 1, wherein the heat transport means includes at least one loop heat pipe pumped by means of a capillary structure.

4. The device according to claim 1, wherein the heat transport means includes at least one immersed loop heat pipe.

5. The device according to claim 1, wherein the heat transport means includes at least one first loop heat pipe comprising a steam line for vaporous heat transfer medium and a liquid line for liquid heat transfer medium, wherein the steam line and the liquid line are disposed in a physically separate manner, the heat transport means includes at least one second heat pipe, the two heat pipes each have a heat-releasing side and a heat-absorbing side, the heat-absorbing side of the at least one first loop heat pipe is disposed inside the external heat source, and the heat-releasing side of the at least one first loop heat pipe is thermally integrated into the heat-absorbing side of the at least one second heat pipe, and the heat-releasing side of the at least one second heat pipe is disposed inside the gasifier pressure vessel.

6. The device according to claim 5, wherein the at least one second heat pipe is a pulsed loop heat pipe which comprises a common steam/liquid line and which is disposed inside the gasifier pressure vessel.

7. The device according to claim 6, wherein the common steam/liquid line has a meander-type shape, in that the heat-releasing side of the pulsed loop heat pipe is disposed in the upper range of the gasifier pressure vessel, and in that the heat-absorbing side is disposed in the base area of the gasifier pressure vessel.

8. The device according to claim 1, wherein the external heat source is a fluidized bed combustion chamber.

9. The device according to claim 1, wherein the gasifier is configured as a fluidized bed gasifier.

10. The device according to either claim 8 or 9, wherein the gasifier pressure vessel is connected to the fluidized bed combustion chamber via a material lock for pyrolysis residues.

11. The device according to claim 9, wherein the fluidized bed gasifier and the fluidized bed combustion chamber are disposed inside a common vessel.