DE102010033926B4 - Device for removing residual quench water from the quenching sump of an entrained flow gasification reactor - Google Patents

Abstract

Apparatus for removing residual quench water from the Quenchersumpf an entrained flow gasification reactor, in which - at the lower end of a quencher (2) a water bath (6) is kept, - the water level (13) in the quencher between a defined minimum and maximum level can be controlled to a desired level - an apron (10) is arranged in the quencher, - the apron extends with its upper edge over the maximum level, - the apron with its lower edge has a predetermined depth below the minimum level, - at the lower edge of the apron a gap ( 11) is formed for the inflow of residual quench water in the space (12) between the skirt and Quencherwandung (8), - the Quencherwandung and the skirt taper down conically, - the gap between Quencherwandung and skirt has substantially constant width, - several water discharge lines (9) for discharging residual quench water below the minimum level and at a predetermined height (16) from the lower edge of the skirt in the rest of the quench water in the space (12) dive.

Description

The invention relates to a device for removing residual quench water from the quenching sump of an entrained flow gasification reactor having the features of claim 1.

In the entrained flow gasification, the raw gas produced is passed together with the forming from the fuel ash slag in a quencher and cooled there by means of water injection. The slag solidifies during this process. In this case, a considerable proportion of fine grain, which is increased by incompletely reacted fuel or by formed soot also falls. The slag and other solids are periodically discharged downwards. The resulting residual quench water is removed and purified in subsequent process steps. In this discharge, the water level in the quencher is regulated between a defined minimum and maximum level. To ensure a continuous drainage of water, the discharge pipe must be submerged below the minimum level. Due to the different rate of descent of coarse and fine solid particles, it is possible that finer solid components are sucked with. This can lead to deposits and blockages as well as wear in downstream systems, which limits the availability of the entire system.

In previously executed plants, it was assumed that the distance between the lower edge of the discharge pipe and the maximum height of the slag deposit is sufficient to avoid the entrainment of fine grain fractions.

• – Mittels Filterkorb bzw. Sieb wird versucht, das Mitführen von Feststoff zu verhindern. Das Problem dieser Lösung besteht darin, dass die Maschenweite des Filters ausreichend grob sein muss, um den notwendigen abzuführenden Volumenstrom an Restquenchwasser zu gewährleisten. Trotzdem kommt es bereits nach wenigen Betriebsstunden zu Verstopfung des Filters bzw. Siebs, was aufwändige Reinigungsschritte notwendig macht.
• – Axial mittig wird ein zusätzliches zentrales Rohr eingebracht, welches oben verschlossen ist. Dadurch wird verhindert, dass Feststoffanteile in dieses Rohr fallen. Da das Rohr nach unten offen ist stellt sich im Rohr der gleiche Wasserspiegel wie außerhalb ein. Somit ist es möglich, das Restquenchwasser in diesem zentral abzuziehen. Durch diese Abführung wird ein Strömungsvektor von unten nach oben erzeugt, was ebenfalls zum Mitreißen von Feinkorn führen kann. Aus diesem Grund ist der Durchmesser des zentralen Rohrs so gewählt, dass die Strömungsgeschwindigkeit geringer ist als die Sinkgeschwindigkeit des Feststoffs. Nachteil dieser Lösung ist, dass der oben befindliche Verschluss des zentralen Rohres direkt im Strömungsquerschnitt der aus dem Reaktionsraum ablaufenden Schlacke liegt und es dadurch zu erheblichen Schlackeablagerungen und -aufwachsungen kommt. Diese führen zur Behinderung des Schlackeabtransports nach unten und müssen periodisch mit erheblichem Aufwand manuell entfernt werden. Dazu ist die Anlage abzufahren und die Befahrbarkeit ist herzustellen.

Externally the following solutions are known:

• - By means of filter basket or sieve is trying to prevent the entrainment of solids. The problem with this solution is that the mesh size of the filter must be sufficiently coarse to ensure the necessary volume flow of residual quench water to be discharged. Nevertheless, clogging of the filter or screen occurs after just a few hours of operation, which makes costly cleaning steps necessary.
• - Axial center, an additional central tube is introduced, which is closed at the top. This prevents solids from falling into this pipe. Since the pipe is open at the bottom, the same water level is created in the pipe as outside. Thus, it is possible to withdraw the residual quench water in this central. By this discharge, a flow vector is generated from bottom to top, which can also lead to the entrainment of fine grain. For this reason, the diameter of the central tube is chosen so that the flow rate is less than the rate of descent of the solid. The disadvantage of this solution is that the closure of the central tube located at the top lies directly in the flow cross-section of the slag leaving the reaction space and, as a result, considerable slag deposits and growths occur. These lead to the obstruction of slag removal down and must be removed manually periodically with considerable effort. For this purpose, the system must be stopped and the trafficability must be established.

From the US 4,852,997 discloses a coal gasification reactor without quencher, in which the discharged slag is separated in a funnel-shaped chamber which at least partially immersed in a water bath. The water from the water bath is withdrawn via a connecting piece, which protrudes from below into the volume between the chamber and the outer wall and which is arranged elevated relative to the discharge opening for the slag. The water is withdrawn at a rate low enough not to entrain slag into the water. The withdrawn water is recycled via a pump and the slag sprayed therewith to carry out a separation of the slag in the water bath.

The invention is based on the problem of designing a device for removing residual quench water from the quenching sump of an entrained flow gasification reactor in such a way that increased separation of fines of the solid is effected and thus avoided that the fines are taken up with the residual quench water and transported into downstream systems.

The problem is solved by a device having the features of claim 1.

The device according to the invention for the removal of residual quench water from the quenching sump of an entrained flow gasification reactor forms a conical space of constant width, in which the flow velocity of the rising residual quench water is steadily reduced by increasing the cross section, thereby already achieving a substantial separation of fines of the solid. By the plurality of water drainage pipes, which dive into the residual quench water from above in the intermediate space, on the one hand a flow reversal with associated turbulence is avoided and on the other causes a gleichmäßigte flow over the circumference of the gap, both of which a more extensive separation of fines of the solid is beneficial , Overall, a separation of fines of the solid from the residual quench water is achieved to a large extent.

Advantageous developments of the invention are specified in the subclaims.

The invention is explained in more detail below as an exemplary embodiment in a scope necessary for understanding with reference to a figure.

Showing:

1 a schematic representation of a realizing the invention quencher.

In a reactor for the autothermal gasification of solid and liquid, ash-containing slag-forming fuels with a free oxygen-containing gasification agents in the air stream at temperatures up to 1850 ° C and pressures up to 10 MPa occurs over the slag process 1 hot synthesis gas together with slag from the reaction chamber located above the quencher (not shown) in the quencher 2 one where it is via quench nozzles 3 injected water 4 is cooled. The cooled gas leaves the quencher via the crude gas line 5 , The likewise cooled slag falls down into the water bath 6 and leaves the quencher over the flange 7 down into the slag lock (not shown). The lower part of the water bath wall is called a cone 8th executed. The slag particles have different sinking rates according to their size, with the fine grain sinking more slowly. To avoid the intake of fine grain through the water discharge lines 9 is a second cone inside 10 intended. Both cones 8th and 10 are mounted inside each other so that there is a gap at the bottom 11 is maintained, through which the Restquenchwasser in the intermediate space 12 can flow. From this space, the water via water discharge lines 9 derived and supplied for further treatment. The gap 11 is dimensioned so that the upward flow force, which by the flowing water in the gap 11 and in the space 12 is applied, smaller than the downward gravity is. This prevents solid particles from being sucked in.

The entire amount of slag is discharged downwards. In the event that there is a Schlacker backwater and thus to the closure of the gap 11 is coming, is above the water level 13 an overflow 14 in the gap 12 intended. Through this, the rising water in the interspace 12 drain and there via Wasserabsaugleitung 9 be sucked off. This case does not correspond to the regular operation and serves only to maintain the discharge of water in the event of an irregular slag removal.

To prevent the slag from falling down in the gap 12 This is a sloping cover 15 Mistake. Because this cover extends only circumferentially over the outer region, no slag discharge-impeding internals or potential slag-deposition surfaces are present in the center.

The inner cone 10 may be generally formed by an insert of any shape or skirt having an upper edge and a lower edge and embracing a space. Any form of insert may be a cylinder.

The drainage pipes dive at a height 16 from the bottom edge of the insert and below the water level 13 into the water in the space 12 one.

LIST OF REFERENCE NUMBERS

1

slag drain

2

quencher

3

quench nozzles

4

injected water

5

raw gas

6

Water bath Restquenchwasser

7

flange

8th

cone

9

Wasserabführleitungen

10

inner cone

11

Crossing-gap

12

gap

13

water level

14

overflow

15

cover

16

Height lower edge skirt drainage pipe

Claims (6)

Device for removing residual quench water from the quenching sump of an entrainment gasification reactor, in which - at the lower end of a quencher ( 2 ) a water bath ( 6 ), - the water level ( 13 ) in the quencher between a defined minimum and maximum level can be regulated to a desired level, - an apron ( 10 ) is arranged in the quencher, - the apron extends with its upper edge over the maximum level, - the apron has with its lower edge a predetermined depth below the minimum level, - at the bottom of the apron a gap ( 11 ) is formed for inflow of residual quench water in the intermediate space ( 12 ) between the skirt and the quencher wall ( 8th ) The quencher wall and the skirt taper conically downwards, the gap between the quencher wall and the skirt has a substantially constant width, a plurality of water discharge ducts, 9 ) for discharging remaining quench water below the minimum level and at a predetermined height ( 16 ) from the lower edge of the skirt into the residual quench water in the gap ( 12 ) immerse. Apparatus according to claim 1, characterized in that the gap is dimensioned so that the upward flow force, which is applied by the flowing water in the gap and in the space, is smaller than the downward gravitational force of the entrained particles. Device according to one of the preceding claims, characterized in that in the intermediate space, the flow velocity of the water is less than the rate of descent of entrained particles. Device according to one of the preceding claims, characterized in that the upper edge of the skirt has an overflow ( 14 ) forms in the intermediate space. Device according to one of the preceding claims, characterized in that a cover ( 15 ) is arranged such that coming from above Good is directed into the space spanned by the skirt. Apparatus according to claim 5, characterized in that the cover falls obliquely to the space spanned by the skirt.

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