EP0616022A1 - Process for pressure gasification of fine particulate fuels - Google Patents

Abstract

In a process for the pressure gasification of fine particulate fuels, a gasification reactor, a quench pipe and a convection boiler are concentrically arranged in a pressure vessel designed for the pressure of the pressure gasification. The crude gas axially leaving the gasification reactor at the top is introduced into the quench pipe connected to the top. A quenching gas is introduced. The mixed gas stream of crude gas and quenching gas is deflected by 180@ by means of a deflection screen which is rotationally symmetrical relative to the axis of the quench pipe and transformed into a hollow-cylindrical gas stream. The hollow-cylindrical gas stream is introduced into the convection boiler which is of hollow-cylindrical shape and concentrically surrounds the quench pipe. On leaving the convection boiler, the crude gas stream is extracted out of the convection boiler by means of a crude gas extraction device. The flow velocity of the crude gas is adjusted such that particles of slag and ash entrained by the crude gas are carried via the 180@ deflection into the hollow-cylindrical convection boiler. The flow velocity in the crude gas extraction device is adjusted such that the entrained particles of slag and ash are discharged.

Description

The invention relates to a method for the pressure gasification of finely divided fuels in the course of the production of process gas. A gasification reactor, a boiler, in particular a convection boiler, and a quenching device are used. - Fine-particle fuels mean fine-grained to dust-like fuels. In particular, it may be coal. The energy is fed to the gasification reactor via burners, which usually also carry the finely divided fuel. From a thermodynamic point of view, the gasification reaction is controlled or regulated as required for the production of a service gas of a predetermined composition. Quenching or quenching the raw gas freezes disturbing reactions. A quench gas is supplied for this purpose. The term gas here also means vapors. In this respect, the prevailing teaching is also used within the scope of the invention. In the corresponding gasification apparatus, the walls of the gasification reactor and the convection boiler and other components for the purpose of hot cooling, e.g. B. in the form of boiling water cooling, tube walls made of different parallel tubes or provided with such tube walls. The convection boiler is equipped with convection heating surfaces. It goes without saying that the heat absorbed via the tube walls and in the convection boiler is used.

The known methods from which the invention is based (cf., for example, EP 0 115 094) work with tower-shaped gasification apparatuses two towers standing side by side. This is complex in terms of process management in detail and structurally. On the other hand, this is often considered necessary to ensure that no disturbances due to deposited slag and / or ash particles occur in the gasification operation. Nevertheless, streak formation which interferes with operational safety must frequently be accepted.

In contrast, the invention has for its object to provide a method for pressure gasification, which is characterized by simple procedure and high operational reliability and can be implemented in a simple and compact gasification apparatus.

• a) in einem Druckbehälter, der für den Druck der Druckvergasung ausgelegt ist, werden ein Vergasungsreaktor, ein Quenchrohr und ein Konvektionskessel konzentrisch angeordnet,
• b) das aus dem Vergasungsreaktor nach oben axial austretende Rohgas wird in das nach oben angeschlossene Quenchrohr eingeführt, welches von dem Konvektionskessel umgeben ist,
• c) ein Quenchgas wird zugeführt,
• d) der Mischgasstrom aus Rohgas und Quenchgas (im folgenden wieder Rohgas) wird oberhalb des Quenchrohres mit einem in bezug auf die Achse des Quenchrohres rotationssymmetrischen Umlenkschirm umd 180° umgelenkt und zu einem hohlzylindrischen Gasstrom umgeformt,
• e) der hohlzylindrische Gasstrom wird in den hohlzylindrisch ausgebildeten Konvektionskessel eingeführt, der das Quenchrohr konzentrisch umgibt,
• f) der Rohgasstrom wird beim Austritt aus dem Konvektionskessel mit Hilfe einer Rohgasabzugseinrichtung aus dem Konvektionskessel abgezogen,

wobei die Strömungsgeschwindigkeit des Rohgases so eingerichtet wird, daß von dem Rohgas mitgerissene Schlacken- und Aschenteile über die 180°-Umlenkung in den hohlzylindrischen Kovenktionskessel getragen werden, in dem sie eine Abkühlung bis zum Verlust ihrer Klebfähigkeit erfahren, und wobei die Strömungsgeschwindigkeit in der Rohgasabzugseinrichtung so eingerichtet wird, daß die mitgerissenen Schlacken- und Aschenpartikel ausgetragen werden. - Die Erfindung geht von der Erkenntnis aus, daß bei der Druckvergasung von feinteiligen Brennstoffen durch eine gleichsam pilzförmige Umlenkung des Mischgasstromes oder Rohgasstromes um 180° mit einem axialsymmetrischen Umlenkschirm ein Strömungsphänomen mit einem hohlzylindrischen Rohgasstrom regeneriert wird, der aus der 180°-Umlenkung resultierende Drallkomponenten durchführt. So wird überraschenderweise jede die Thermodynamik störende Strähnenbildung vermieden - Überraschenderweise induzieren die Drallkomponenten in dem Rohgasstrom auf seinem Weg durch den Konvektionskessel ein Turbulenzspektrum mit weitgehend homogener isotroper Turbulenz, die den Wärmeübergang verbessert. Ohne Schwierigkeiten kann die Strömungsgeschwindigkeit des Rohgases so eingerichtet werden, daß von dem Rohgas mitgerissene Schlacken- und Aschenpartikel über die 180°-Umlenkung in den hohlzylindrischen Konvektionskessel getragen werden, und zwar bei sehr gleichmäßiger Verteilung. Die so eingerichtete Störmungsgeschwindigkeit des Rohgases im Quenchrohr führt gleichzeitig dazu, daß die vorstehend beschriebenen Drall- und Turbulenzphänomene besonders ausgeprägt und gleichförmig sind. Im Ergebnis kann in einem Konvektionskessel verhältnismäßig geringer Bauhöhe erreicht werden, daß die Schlacken- und Aschenpartikel auf ihrem Wege durch das Quenchrohr und durch den Konvektionskessel eine Abkühlung bis zum Verlust ihrer Klebfähigkeit erfahren. Ohne weiteres können auch die Strömungsgeschwindigkeiten in der Rohgasabzugseinrichtung so eingerichtet werden, daß die mitgerissenen Schlacken- und Aschenpartikel ausgetragen werden, wo sie abgeschieden werden können. Das erfindungsgemäße Verfahren erlaubt es, in dem Vergasungsapparat für die Durchführung des Verfahrens auf feuerfeste Auskleidungen zu verzichten. Abklopfer sind regelmäßig ausreichend.To achieve this object, the invention relates to a process for the pressure gasification of finely divided fuels with the following process steps:

• a) a gasification reactor, a quench tube and a convection boiler are arranged concentrically in a pressure vessel which is designed for the pressure of the pressure gasification,
• b) the raw gas emerging axially upward from the gasification reactor is introduced into the quench tube connected upward, which is surrounded by the convection boiler,
• c) a quench gas is supplied,
• d) the mixed gas stream of raw gas and quench gas (in the following again raw gas) is deflected above the quench tube with a deflection screen which is rotationally symmetrical with respect to the axis of the quench tube and is converted into a hollow cylindrical gas stream,
• e) the hollow-cylindrical gas flow is introduced into the hollow-cylindrical convection vessel which concentrically surrounds the quench tube,
• f) the raw gas stream is withdrawn from the convection boiler on leaving the convection boiler with the aid of a raw gas extraction device,

wherein the flow rate of the raw gas is set up such that slag and ash parts entrained by the raw gas are carried over the 180 ° deflection into the hollow-cylindrical convection boiler, in which they are cooled until they lose their adhesiveness, and the flow rate in the raw gas extraction device is set up so that the entrained slag and ash particles are discharged. - The invention is based on the knowledge that in the pressure gasification of finely divided fuels by a mushroom-shaped deflection of the mixed gas flow or raw gas flow by 180 ° with an axially symmetrical deflection screen, a flow phenomenon with a hollow cylindrical raw gas flow is regenerated, the swirl components resulting from the 180 ° deflection carries out. So will Surprisingly, any streak formation that disturbs the thermodynamics is avoided. Surprisingly, the swirl components in the raw gas stream on their way through the convection boiler induce a turbulence spectrum with largely homogeneous isotropic turbulence, which improves the heat transfer. The flow rate of the raw gas can be set up without difficulty so that slag and ash particles entrained by the raw gas are carried via the 180 ° deflection into the hollow cylindrical convection boiler, with a very uniform distribution. The rate of disturbance of the raw gas in the quench tube thus set also leads to the fact that the swirl and turbulence phenomena described above are particularly pronounced and uniform. As a result, in a convection boiler of relatively low overall height, the slag and ash particles can be cooled as they pass through the quench tube and through the convection boiler until they lose their adhesiveness. The flow velocities in the raw gas extraction device can also be set up in such a way that the entrained slag and ash particles are discharged where they can be separated off. The method according to the invention makes it possible to dispense with refractory linings in the gasification apparatus for carrying out the method. Tappers are usually sufficient.

The advantages and effects described are particularly pronounced if the deflected raw gas stream is guided past concentric convection heating surfaces in the convection boiler and to a temperature of 400 ° to 200 ° C. upon entry into the raw gas extraction device is cooled. The supply of the quench gas can also have an effect on the thermodynamics in the process according to the invention for homogenization and homogenization and thus for suppressing streak formation and disadvantageous influences, namely in that the quench gas is distributed in a uniform distribution between the gasification reactor and the quench tube with the aid of a rotating quench gas supply gap the entire circumference and in cross flow to the raw gas is introduced into the quench tube. The quench gas is preferably introduced into the quench tube via a built-in quench gas supply gap.

If the process according to the invention is used, the concentric convection heating surfaces surround the quench tube. For the convection heating surfaces there is therefore an annular space with an annular disk-shaped plan, in which a large convection heating surface can be accommodated without difficulty. While tower-like boilers with concentric convection heating surfaces have a thermodynamically ineffective area in the center, in the method according to the invention this area is used to hold the quench tube. The systems or apparatuses that result from the teaching of the method according to the invention when introduced into practice are surprisingly compact with high performance and high throughput. The heat transfer and thus the cooling of the raw gas take place very intensively according to the invention, because both the wall of the quench tube and the convection heating surfaces are flowed around and acted upon on both sides by the gas to be cooled. In order to guide the exit of the cooled raw gas in such a way that slag and ash particles do not deposit in the raw gas extraction device, The invention teaches that a swirl flow is impressed on the raw gas stream as it exits the convection boiler in the flue gas extraction device and the flow rate and swirl in the raw gas extraction device are set up in such a way that entrained slag and ash particles are discharged.

Fig. 1

eine Ansicht eines Vergasungsapparates,

Fig. 2

in gegenüber der Fig. 1 wesentlich vergrößertem Maßstab den Ausschnitt A aus dem Gegenstand der Fig. 1,

Fig. 3

im Maßstab der Fig. 2 den Ausschnitt B aus dem Gegenstand nach Fig. 1,

Fig. 4

im Maßstab der Fig. 2 den Ausschnitt C aus dem Gegenstand der Fig. 1,

Fig. 5

in gegenüber den Fig. 1 bis 4 nochmals vergrößertem Maßstab den Ausschnitt D aus dem Gegenstand der Fig. 3,

Fig. 6

einen Schnitt in Richtung E-E durch den Gegenstand der Fig. 5 und

Fig. 7

in gegenüber den Fig. 1 bis 4 vergrößertem Maßstab den Ausschnitt F aus dem Gegenstand der Fig. 1.

In the following, the invention will be explained in more detail with reference to a drawing representing only one exemplary embodiment, specifically with the aid of a gasification apparatus which is set up for the method according to the invention. They show a schematic representation

Fig. 1

a view of a gasification apparatus,

Fig. 2

in a significantly enlarged scale compared to FIG. 1, section A from the subject of FIG. 1,

Fig. 3

2 shows the detail B from the object according to FIG. 1,

Fig. 4

2 the section C from the subject of FIG. 1,

Fig. 5

1 to 4, on a further enlarged scale, the detail D from the subject of FIG. 3,

Fig. 6

a section in the direction of EE through the subject of Fig. 5 and

Fig. 7

on an enlarged scale compared to FIGS. 1 to 4, the detail F from the subject of FIG. 1.

The gasification apparatus shown in the figures is intended for the pressure gasification of finely divided fuels in the course of the production of process gas and is set up in such a way that it results from the method according to the invention. In Fig. 1, a middle part has not been shown, the length of which corresponds approximately to the length of the lower part.

The basic structure of the gasification apparatus includes a gasification reactor 1, a quench tube 2 for the raw gas emerging from the gasification reactor 1 and a convection boiler 3 with convection heating surfaces 4 for receiving the waste heat of the raw gas. It is understood that the convection heating surfaces 4 are expediently arranged in the form of concentric cylinders. As already mentioned at the beginning, the apparatuses described are constructed from tube walls, which in turn consist of tubes which are guided in parallel and welded to one another.

It can be seen from FIG. 1 that the gasification reactor 1, the quench tube 2 and the convection boiler 3 are arranged with a boiler housing 5 in a pressure vessel 6. The convection boiler 3 surrounds the quench tube 2 concentrically. The gasification reactor 1 is arranged coaxially under the quench tube 2. The boiler housing 5 also suitably consists of tube walls. One can see in the upper part of FIGS. 1, 2 the suspension of a bundle of Convection heating surfaces 4 on the quench tube 2 and on the boiler housing 5. In the same way, further bundles of convection heating surfaces can be arranged distributed over the height of the gasification apparatus.

Above the quench tube 2, a deflection device 7 is arranged or formed in the boiler housing 5 for the raw gas emerging from the quench tube 2 and to be introduced into the convection boiler 3. For this purpose, reference is also made in particular to FIG. 2. In particular in Fig. 3 it can be seen that a raw gas outlet device 8 is arranged in a region between the gasification reactor 1 and convection boiler 3, with which the raw gas from the boiler housing 5 and the pressure vessel 6 is carried out. A swirl-producing deflection of the raw gas emerging from the convection boiler takes place with the aid of guide vanes 8a indicated in FIG. 3. The design is such that the escaping raw gas entrains slag and ash particles so that there are no disturbing deposits in this area. The cooling of the raw gas and thus the Schiackeparticle was carried out so far that baking is not possible. From Fig. 4 it can be seen that the gasification reactor 1 is fixed in the lower part of the pressure vessel 6 in this. The fixed points 9 indicate this.

The convection heating surfaces 4 are carried by the quench tube 2 and the Kesseie housing 5. The quench tube 2 and the boiler housing 5 are placed in their lower area, above the raw gas outlet device 8, on load discharge elements 10, which have raw gas passages 11 and are fixed to the pressure vessel 6 are. In this regard, reference is made in particular to FIGS. 3, 5 and 6 with the fixed points 12.

In particular, from FIG. 4 it can be seen that a circumferential quench gas introduction gap 13 is arranged between the gasification reactor 1 and the quench tube 2. This separates the quench tube 2 and the gasification reactor 1. The arrangement is such that between the quench tube area below the load transfer elements 10, on the one hand, and the gasification reactor 1 above its fixed point bearing 9, on the other hand, different, also pressure-vessel-related, thermal expansions are permitted. For this purpose, the quench gas introduction gap 13 is additionally dimensioned as a thermal expansion compensation gap.

In the exemplary embodiment and according to a preferred embodiment of the invention, the pressure vessel 6 is at the same time set up as a supporting structure for the gasification reactor 1, the quench tube 2 and the convection boiler 3 with boiler housing 5 and statically and in terms of stability. The already mentioned deflection device 7 is designed in the exemplary embodiment as a hood-shaped impact deflection device. The raw gas outlet device 8 has a device 14 for the discharge of slag and / or ash particles, which is described in detail below.

In particular, from FIG. 4 it can be seen how the gasification reactor 1 is fixed in its lower region on brackets 15 of the pressure vessel 6.

The convection heating surfaces 4 are fastened on one side to supporting cross members 16. The cross members 16 are connected to the boiler housing 5 and the quench tube 2 without tension in order to avoid constraints from different thermal expansion of the boiler housing or the quench tube. In the simplest case, the traverses 16 are statically supported as beams on two supports.

The details of the load transfer elements 10 can be seen in particular from FIGS. 5 and 6. These are designed as rigid, metallic components with an inner ring 17, outer ring 18 and spokes 19. The intermediate spaces form the raw gas passages 11. The components 17, 18, 19 described are made in one piece, for. B. as forgings. The load transfer elements 10 are connected to the load-bearing elements in the pressure vessel 6 via heated supports or a heated frame 20 on the boiler housing 5. It was indicated in FIG. 5 that the load transfer elements 10 are at the same time designed as a feed device for the boiling water of a boiling water cooling of the quench tube-forming pipelines of the tube wall of the quench tube 2. For this purpose, reference is made to the pipes or channels 21. The boiling water is discharged via heat expansion deformable discharge pipes 22 connected to the top of the quench pipe 2 or its pipes. In this respect, apart from the pipes on and in the load transfer elements 10, all pipe connections between the quench pipe 2 and the boiler housing 5 are designed and arranged to be elastically deformable .

The gasification reactor 1 forms an annular space 23 opposite the wall of the pressure vessel 6. The quench gases to be supplied become via this annular space 23 to the quench gas introduction gap 13. The annular space 23 is also connected to a pressure compensation space 24 which has remained free between the boiler housing 5 and the pressure vessel 6.

The quench gas introduction gap 13 is particularly advantageous in the exemplary embodiment. It is formed between a conically drawn-in output component 25 of the gasification reactor 1 and a skirt 26 of the quench tube 2 which is complementary thereto. The output component 25 is designed on the gasification reactor chamber side free of a refractory lining with a metallic blank. The cone angle is approximately 60 °. All surfaces located downstream of the output component 25 are also free of a refractory lining. Was indicated in Fig. 7 that the output member 25 of the gasification reactor 1 is provided with a cleaning ring 27 and this periodically, for. B. is movable by means of tapping.

In order to ensure a clear flow direction of the quench gas through the gap 13, the annular space between the peripheral wall of the gasification reactor 1 and the pressure vessel 6 is closed by a membrane 28. The pressure compensation in the area below the membrane is established via the slag discharge opening in the bottom of the gasification reactor 1.

From a comparative examination of FIGS. 1 to 7 it can be seen that the following method is implemented:
In the pressure vessel 6, which is designed for the pressure of the pressure gasification, a gasification reactor 1, a quench tube 2 and a convection boiler 3 are arranged concentrically. The raw gas emerging axially upward from the gasification reactor 1 is introduced into the quench tube 2 connected upward. A quench gas is supplied. The mixed gas stream of raw gas and quench gas, which is referred to again below as raw gas, is deflected above the quench tube 2 by means of a deflection device 7 which is rotationally symmetrical with respect to the axis of the quench tube 2 in the form of a deflecting screen and is converted into a hollow cylindrical raw gas stream. The hollow-cylindrical raw gas flow is introduced into the hollow-cylindrical convection boiler 3, which concentrically surrounds the quench tube 2. The raw gas stream is withdrawn from the convection boiler 3 when it leaves the convection boiler 3 with the aid of a raw gas outlet device 8. The flow rate of the raw gas is first set up in such a way that slag and ash parts entrained by the raw gas are carried via the 180 ° deflection into the hollow cylindrical convection boiler 3, in which they cool down until they lose their adhesiveness. The flow in the raw gas outlet device 8 is set up so that the entrained slag and ash parts are discharged. The exemplary embodiment shows that the deflected raw gas stream is guided past concentric convection heating surfaces 4 in the convection boiler 3 and is cooled to a temperature of 400 to 200 ° C. upon entry into the raw gas outlet device 8. The quench gas is in a circulating quench gas introduction gap 13 between the gasification reactor 1 and the quench tube 2 in uniform distribution over the entire circumference and introduced into the quench tube 2 in cross flow to the raw gas. A swirl flow is impressed on the raw gas flow when it leaves the convection boiler 3 in the raw gas outlet device 8. The flow rate and the swirl in the raw gas outlet device 8 are set up so that entrained slag and ash particles are discharged.

Claims (5)

Process for the pressure gasification of fine-particle fuels with the following process steps: a) a gasification reactor, a quench tube and a convection boiler are arranged concentrically in a pressure vessel which is designed for the pressure of the pressure gasification, b) the raw gas emerging axially upward from the gasification reactor is introduced into the quench tube connected upward, which is surrounded by the convection boiler, c) a quench gas is supplied, d) the mixed gas stream of raw gas and quench gas (in the following again raw gas) is deflected above the quench tube with a deflection screen which is rotationally symmetrical with respect to the axis of the quench tube and is converted into a hollow cylindrical gas stream, e) the hollow-cylindrical gas flow is introduced into the hollow-cylindrical convection vessel which concentrically surrounds the quench tube, f) the raw gas stream is withdrawn from the convection boiler on leaving the convection boiler with the aid of a raw gas extraction device, wherein the flow rate of the raw gas is set up so that slag and ash parts entrained by the raw gas are carried over the 180 ° deflection into the hollow cylindrical convection boiler, in which they are cooled until their tackiness is lost, and wherein the flow rate in the raw gas extraction device is set up so that the entrained slag and ash particles are discharged. A method according to claim 1, wherein the deflected raw gas stream is guided past concentric convection heating surfaces in the convection boiler and is cooled to a temperature of 200 ° to 400 ° C upon entry into the raw gas extraction device. Method according to one of claims 1 or 2, wherein the quench gas is introduced into the quench tube with the aid of a circulating quench gas supply gap between the gasification reactor and the quench tube in a uniform distribution over the entire circumference and in cross-flow with the raw gas. The method of claim 3, wherein the quench gas is introduced into the quench tube via a built-in quench gas supply gap. Method according to one of claims 1 to 4, wherein a swirl flow is impressed on the raw gas flow when it emerges from the convection boiler in the raw gas extraction device and the flow velocity and the swirl in the raw gas extraction device are set up in such a way that entrained slag and ash particles are discharged.

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