JPH0678542B2 - Method and apparatus for cooling hot product gas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of cooling hot product gases containing sticky particles that lose stickiness on cooling.

Sticky particles in the hot product gas cause an obstacle in the plant for further processing of the product gas. This is because undesired deposition of particles, for example on walls, valves or outlets, adversely affects the process. Moreover, these deposits are very difficult to remove.

The hot product gas can be obtained from the partial combustion of carbonaceous material, where the product gas has a temperature in the range 1000 ° C to 1800 ° C. The sticky particles may be in a partially or completely molten state, they may consist of metal, salt or ash,
And generally these particles lose tack at temperatures below about 800 ° C.

It is an object of the present invention to provide a simple method of cooling hot product gas containing sticky particles which lose stickiness on cooling.

To this end, the method according to the invention comprises passing the hot product gas through a cooling zone and injecting into the product gas stream at least one frustoconical annular jet of cooling fluid tapering in the direction of the product gas stream. Including.

The annular jet of cooling fluid causes the product gas to flow through the mixing zone where it is vigorously mixed with the cooling gas so that the product gas is cooled. The mixing zone, which includes a converging first portion and a diverging second portion, is surrounded by an annular recirculation zone that separates the sticky particles from the walls of the cooling zone.

The invention further provides an apparatus for carrying out the method for cooling a hot product gas according to the invention, wherein the cooling zone, inlet conduit means connectable to the hot product outlet, and the product gas during normal operation. Including at least one frustoconical cooling fluid conduit that tapers in the direction of passage, a frustoconical cooling fluid conduit having a circumferential outlet opening into the device, and a frustoconical cooling fluid conduit inlet for supplying cooling fluid. Relates to said device being connectable.

The method and device according to the invention will be described in more detail by way of example with reference to the drawings.

First, referring to FIG. The device according to the invention comprises a tubular cooling section 11, inlet conduit means in the form of a tubular inlet conduit 12, and a frustoconical cooling gas conduit 13 which tapers upwards.

The walls of the cooling zone 11 and of the inlet conduit 12 may be made of a suitable metal such as refractory or steel, and the frustoconical cooling gas conduit 13 may be made of a suitable metal such as steel.

The frustoconical cooling gas conduit 13 is an annular conduit with an inlet conduit 15.
Connected to 14.

During operation of the device, the inlet conduit 12 of the device is connected to an outlet (not shown) for hot product gas and the hot product gas causes the cooling zone 11 to rise in an upward direction (parallel to the central longitudinal axis 18 of the cooling zone 11). (Indicated by arrow 19). Furthermore, a cooling gas is supplied to the inlet conduit 15, which frustates the circumferential outlet opening 21 of the frustoconical cooling gas conduit 13 in the direction of the flow of the hot product gas indicated by the arrow 19. Leave as circular jet 22.

An annular jet 22 of cooling gas causes hot product gas containing sticky particles to flow through a mixing zone 23 surrounded by a recirculation zone 24. The mixing zone 23 comprises a converging first portion 25 in which the hot product gas is rapidly mixed with the cooling gas and a diverging second portion 27 in which the mixing and cooling is completed in a turbulent jet.

At the end of the second part 27 of the mixing zone 23 there is a collision zone 30; downstream of this collision zone 30 the temperature is such that the particles in the product gas are de-sticky and therefore they adhere to the walls of the cooling zone 11. It is so low that I can't do it. Furthermore, the temperature of the particles in the mixture of product gas and cooling gas in the recirculation zone 24 is such that the particles are no longer sticky and therefore they do not stick to the walls of the cooling zone 11.

The mixture of product gas and cooling gas in the recirculation zone 24 acts as an intermediate layer separating the walls of the cooling zone 11 from the sticky particles in the mixing zone 23.

Downstream of the collision zone 30, the product gas and cooling gas mixture is withdrawn from the cooling zone 11 through a conduit (not shown) to a plant (not shown) for further processing of the product gas.

The apparatus may be used, for example, to cool the product gas exiting the gasification reactor which partially oxidizes carbonaceous material.

It will be appreciated that the device according to the invention can also be used for cooling the product gas leaving the gasification reactor for the partial oxidation of fluids and / or gaseous hydrocarbons.

If the gasification process is carried out under elevated pressure, the device according to the invention is placed in a pressure vessel (not shown).

In order to increase the length of the cooling passage between the circumferential exit opening of the frustoconical cooling gas conduit and the impingement zone during normal operation, the invention further provides that the cross-sectional area of the passage is greater than that of the tubular inlet conduit 37. Also provided is a device including a larger tubular cooling zone 36 (see FIG. 2) and a transition zone 38 interconnecting the inlet conduit 37 and the cooling zone 36, the transition zone being flat or the product during normal operation. The gas may be spread in the direction through the device.

The apparatus further comprises a first frustoconical cooling gas conduit having a circumferential outlet opening 42 located near the transition zone 38 in the inlet conduit 37.
Including 41. The frustoconical cooling gas conduit 41 is connected to an annular conduit 45 having an inlet conduit 46.

In order to further increase the length of the cooling path, the device is equipped with a circumferential outlet opening.
It also includes a second frustoconical cooling gas conduit 48 having 49 and connected to an annular conduit 50 having an inlet conduit 51.

The frustoconical cooling gas conduits 41 and 48 taper in the upward direction, which is the direction that product gas is passed through the device during normal operation.

During normal operation of the system, hot product gas is fed to the inlet conduit 37 and passed through the cooling zone 36 in the upward direction (indicated by arrow 55). In addition, cooling gas is supplied to the inlet conduits 46 and 51, which leave the circumferential outlet openings 42 and 49 in the form of first and second frustoconical annular jets, designated by the reference numerals 56 and 57, respectively.

The first frustoconical annular todget 56 delivers hot product gas,
Having a convergent and divergent portion and passing through a first mixing zone 58 surrounded by an annular recirculation zone 59, a second frustoconical annular jet 57 contains product and cooling gas, and a convergent and divergent portion. And passes through a second mixing zone 60 surrounded by an annular recirculation zone 61.

At the downstream end of the second mixing zone 60, the temperature is such that the particles are detackified and therefore they do not stick to the walls of the cooling zone 36, from which the gas mixture further processes the product gas. Sent to a plant (not shown).

The inner diameter of the cooling zone can range from 1.5 to 3 times the inner diameter of the inlet conduit.

The device described with respect to FIG. 1 in which the inner diameter of the cooling zone 11 is equal to the inner diameter of the inlet conduit 12 can also include a second frustoconical cooling gas conduit (not shown) to increase the length of the cooling passage.

In order to improve the flexibility of the operation, the device according to the invention can comprise more than two frustoconical cooling gas conduits whose circumferential outlet opening is open during operation and whose inlet can be connected to a supply of cooling gas. .

In order to prevent hot particles passing through the mixing zone from contacting the wall of the cooling zone between two subsequent annular outlet openings during normal operation, the distance between the two openings is 1 to 4 of the inner diameter of the cooling zone. Should be in double range.

In other embodiments of the present invention, the cross section of the cooling zone and of the inlet conduit can be rectangular or square.

In order to increase the residence time of the particles in the mixing zone and to obtain good mixing, the speed of injecting the cooling gas into the product gas stream is in the range of 5 m / s to 100 m / s, especially 20 m / s to 60 m / s. should be in the range of s.

The velocity of the hot product gas entering the device should be greater than 1 m / s to prevent large backflow of the relatively dense cold gas.

Suitable thickness of frustoconical cooling gas conduit is 0.5mm to 10mm
Is the range. The apex angle 63 (see FIG. 1) of the frustoconical cooling gas conduit 13, also referred to as the injection angle, can range from 0 ° to 90 °. In order to reduce the risk of backflow of the frustoconical annular jet of cooling gas, to improve mixing in the mixing zone and to obtain an optimal length of the cooling channel, the apex angle 63 of the frustoconical cooling gas conduit 13 is 20 ° to 70
It should be in the range of °.

To represent the amount of mixing, a dimensionless ratio of momentum flow rates is introduced, which is the mass flow rate of cooling gas (kg / s) multiplied by the injection rate of cooling gas (m / s). It is defined as the momentum flow rate of the cooling gas, which is the product, divided by the mass flow rate of the product gas (kg / s) multiplied by the velocity of the product gas entering the equipment. . To obtain good mixing, the momentum flow rate is preferably greater than 1, more preferably greater than 5.

[Brief description of drawings]

FIG. 1 is a schematic longitudinal sectional view of an apparatus having one frustoconical cooling gas conduit, and FIG. 2 is a schematic vertical sectional view of an apparatus having two frustoconical cooling gas conduits. 11,36 …… Cooling area, 12,37 …… Product gas inlet conduit, 1
3,41,48 ... Frustaconical cooling gas conduit, 14,45,50 ... annular conduit.

Claims (10)

[Claims] 1. A method of cooling a hot product gas containing sticky particles which loses tackiness upon cooling, wherein the hot product gas is passed through a cooling zone and in the product gas stream, the direction of the product gas stream. Said cooling method comprising injecting at least one frustoconical annular jet of cooling fluid that tapers into the. 2. A method according to claim 1 wherein the hot product gas is obtained by partial combustion of carbonaceous material. 3. A method according to claim 1 or 2 in which the cooling fluid is passed through a frustoconical cooling gas conduit which tapers in the direction of the product gas flow. 4. A method according to claim 1, wherein the cooling fluid is injected into the product gas stream at a rate of 5 m / s to 100 m / s.
The method according to any of the items. 5. A process as claimed in any one of claims 1 to 4, wherein the rate at which the hot product gas enters the device is greater than 1 m / s. 6. A method according to claim 1, wherein the ratio of momentum flow rates defined below is greater than 1. 7. An apparatus for carrying out the method for cooling a hot product gas according to any one of claims 1 to 6, wherein the inlet section means is connectable to a cooling zone, a hot product outlet. , And at least one frustoconical cooling fluid conduit that tapers in the direction in which the product gas is passed through the device during normal operation, a frustoconical cooling fluid conduit having a circumferential outlet opening into the device and a cone The apparatus wherein the inlet of the trapezoidal cooling fluid conduit is connectable to a supply of cooling fluid. 8. The apparatus of claim 7 wherein the frustoconical cooling fluid conduit has an apex angle in the range of 20 ° to 70 °. 9. The invention of claim 7 wherein the cross-sectional area of the passages of the cooling zone is greater than the cross-sectional area of the passages of the inlet conduit means, and the device further comprises a transition zone interconnecting the inlet conduit means and the cooling zone. Or the apparatus according to item 8. 10. The transition zone comprises a wall wherein product gas spreads through the device during normal operation.
The device according to the item.