EP1411296B1 - Oxygen lance for the high-temperature gasification of waste and method of operation - Google Patents

Abstract

An oxygen lance for high temperature gasification of optionally thermally-pretreated waste has channels (I, II and III) for transport of reaction oxygen, introduction of fuel and introduction of oxygen fuel, channel (I) being identical to channel (II) and containing a device which controls the introduced oxygen in at least two flow-through conditions. An Independent claim is also included for operating the lance in a high temperature reactor by operating with a permanent flame and operating firstly with the fuel and oxygen for the flame in approximately stoichiometric ratio and secondly with the oxygen in a super-stoichiometric ratio to the fuel such that a fraction of the oxygen acts as reaction partner in the high temperature reactor, the oxygen pressure always being chosen such that it is higher than the partial pressure in the high temperature reactor.

Description

The invention relates to an oxygen lance according to the features of the preamble of claim 1 and a method for operating the same in a high-temperature reactor.

For the gasification of heterogeneous waste, it is known to realize the oxygen supply to the gasification bed, for example in a high-temperature reactor, by means of oxygen lances. Oxygen lances in the sense referred to here are water-cooled nozzles, with which usually oxygen or oxygen-enriched air is injected into the inner combustion chamber of gasification reactors.

The German Patent 195 12 249 C2 teaches to use oxygen lances with at least one permanently burning pilot flame of high flame temperature and high burning rate are operated such that the lance oxygen is accelerated to at least approximately sound velocity, whereby the lance oxygen is also extremely heated. The high temperature of the oxygen increases the gasification rate, the strong acceleration of the oxygen decisively increases the range of action of the lance.

In the prior art, an oxygen lance is used for this, which is equipped with a burner for generating the pilot flame. This burner / oxygen lance combination is characterized in particular by the fact that in addition to a first oxygen channel, which serves to introduce oxygen into the gasification bed of the reactor, a separate, second oxygen channel is provided, which provides the supply of the pilot flame generated by the burner with oxygen.

If there is no supply of oxygen to the gasification bed of the reactor and only the pilot flame is operated (burner operation), there is a risk that hot synthesis gas from the reactor due to the partial overpressure in the reactor in the first oxygen channel, which now yes no oxygen is supplied , diffused into it. This is particularly dangerous because the mixture of hot synthesis gas and oxygen in the first oxygen channel can lead to deflagration as soon as the introduction of oxygen into the gasification bed of the reactor is switched on again for burner operation.

Diffuses hot synthesis gas in previously described burner operation in the first channel for the supply of Oxygen in the gasification bed of the reactor, so there is the disadvantage that due to the temperature difference between the hot synthesis gas and the usually cooled with water oxygen lance combination condensable components of the synthesis gas in the first, disconnected oxygen channel at least partially condense.

Object of the present invention is to provide a burner / oxygen lance combination and a method for their use, which can be used in the burner operation and thereby meets the above-mentioned in the assessment of the prior art risks and disadvantages.

This object is achieved with an oxygen lance according to claim 1 and a method for operating the same according to claim 7.

In particular, this solution has the following advantages:

The fact that the channel for the transport of reaction oxygen, ie the oxygen which is introduced into the gasification bed of the reactor for reaction, is identical to the channel for supplying fuel oxygen, that is the oxygen for supplying the burner or pilot flame, is achieved particularly advantageously in that, irrespective of whether the burner / oxygen lance combination is driven into the gasification bed of the reactor while the pilot flame is always burning, with or without supply of oxygen, an oxygen stream is always passed through the oxygen channel, since at least the burner flame with the quantity necessary for the stoichiometric combustion Oxygen (fuel oxygen) is supplied. To this Thus, non-hot syngas from the reactor may diffuse into the oxygen channel and avoid the risk of deflagration upon re-start of the oxygen supply to the gasification bed of the reactor (reaction oxygen) while precluding the condensation of hot syngas in the reaction oxygen feed channel.

Furthermore, the device construction of the oxygen lance with burner device as a whole is simplified, since connections and additional channels for the separate feed of oxygen for pilot / burner flame on the one hand and the oxygen supply to the gasification bed of the reactor on the other hand omitted.

The fact that a control device is included which controls the amount of oxygen supplied in at least two different passage states, on the other hand, the respectively necessary for the two operating conditions burner flame and supply of reaction oxygen in the gasification bed on the one hand and burner flame without supply of reaction oxygen in the gasification Quantity of oxygen metered fed.

In this case, in the operating mode "burner flame without supply of reaction oxygen into the gasification bed", the reactants fuel and oxygen are supplied in an approximately stoichiometric ratio for the combustion in the burner flame. In the operating mode "burner flame with supply of reaction oxygen into the gasification bed", however, the oxygen is supplied in a stoichiometric ratio to the fuel, so that the proportion of the supplied oxygen content of the stoichiometric Ratio to combustion in the burner flame is necessary goes beyond, is fed as a reactant to the combustion bed of the high temperature reactor.

Fuel in the context of this entire application may be, for example, methane gas, process-own synthesis gas or individual components thereof as well as liquid and / or pumpable, pollutant-containing substances.

By always selecting the pressure of the oxygen - especially when the burner flame is operated alone - so that it is always greater than the partial pressure in the high-temperature reactor, a diffusion of hot synthesis gas into the oxygen supply line is effectively prevented.

Advantageous developments of the invention are possible according to the subclaims 2 to 6 or 8 to 10 and are briefly explained below:

An advantageous embodiment for a control device which controls the amount of oxygen supplied in at least two different passage states is the realization as valves connected in parallel in the oxygen flow. This achieves a robust and technically particularly simple way of producing the required pass states with precisely adjustable and constant passage quantities.

Another development of the invention provides to provide the reactor-side end of the burner / oxygen lance combination with an interchangeable lable burner head. This is on the one hand advantageous since the burner head is exposed to the hot atmosphere of the high-temperature reactor and thus has only a limited service life as a wearing part, so that a quick and easy interchangeability significantly simplifies the maintenance of the oxygen lance. On the other hand, the interchangeability of such a burner head is particularly favored by the property of the invention that the structural design of the oxygen lance on the reactor side final burner head and the connection between the burner head and oxygen lance in its construction is significantly simplified by the inventive saving of supply channels. Thus, the burner head can be realized by a plug or a screw connection, which is in spatial agreement with the channels of the oxygen lance.

An advantageous development of the method for operating the oxygen lance provides for the control device to be switched over in a pulsating manner between the two operating states. In this way, the reaction oxygen introduced into the gasification bed of the reactor by the oxygen lance is introduced in a pulsed manner, so that there is the advantage that channels in the gasification bed, which may have been formed by the oxygen jet of the lance, collapse during the pauses in the pulse. Thus, "bridging" in the gasification bed is avoided.

Fig. 1

eine schematische Darstellung einer Sauerstofflanze zur Hochtemperaturvergasung heterogener Abfälle nach dem Stand der Technik (A) sowie einer erfindungsgemäßen Sauerstofflanze zum selben Zweck (B);

Fig. 2

einen Längs- und einen Querschnitt durch eine detailliertere Ausführungsform einer Sauerstofflanze als Ausführungsbeispiel der Erfindung mit auswechselbarem Brennerkopf; sowie

Fig. 3

eine Darstellung einer durch zwei im Sauerstoffstrom parallel geschaltete Ventile implementierten Steuervorrichtung mit einem weiteren Ventil zur Zuführung von Brenngas.

The invention will be explained below with reference to a schematic representation and an embodiment. Show it:

Fig. 1

a schematic representation of an oxygen lance for high-temperature gasification heterogeneous Waste according to the prior art (A) and an oxygen lance according to the invention for the same purpose (B);

Fig. 2

a longitudinal and a cross section through a more detailed embodiment of an oxygen lance as an embodiment of the invention with replaceable burner head; such as

Fig. 3

an illustration of a control device implemented by two valves connected in parallel in the oxygen flow with a further valve for supplying fuel gas.

Fig. 1 shows a schematic representation of an oxygen lance for high-temperature gasification of heterogeneous waste according to the prior art (A) and as an embodiment of the present invention (B) in juxtaposition.

In the model according to the prior art, three concentrically running in one another, tubular flow channels are realized, which are provided in the present case with supply nozzle. In the prior art oxygen lance (A), the outermost channel is the fuel gas supply channel I. Therein is the oxygen supply channel for pilot flame operation in the burner II, and again, there is the supply channel III Oxygen as a reactant in the combustion bed of the high temperature reactor.

In the embodiment of the invention B, however, the fuel supply channel I is internal. It surrounds him a single oxygen channel II, to which the known from the prior art separate supply channels for combustible oxygen and reaction oxygen are summarized.

If the burner / oxygen lance combination B is only used in burner operation without oxygen being introduced as a reactant into the combustion bed of the reactor, then the fuel channel I and the oxygen channel II lead in each case as much fuel or oxygen as for the stoichiometric combustion in the pilot flame of Burner is required, wherein the pressure of the oxygen for the burner is chosen so that it is always above the partial pressure in the high-temperature reactor, so that penetration of hot synthesis gas is excluded in the oxygen supply. If, in addition, oxygen as reaction oxygen enters the combustion bed of the reactor, then correspondingly more oxygen is supplied in the oxygen channel II.

The supply is provided by the control device not shown in detail in this figure.

Fig. 2 shows a longitudinal section through a more detailed embodiment of a burner / oxygen lance combination according to the invention. Again, the channel for supplying fuel gas I and the channel for supplying oxygen II, which surrounds the channel for fuel, so that nested tubes arise shown. This becomes particularly clear in the cross-section along the axis AA, shown at the bottom right.

Furthermore, the connection valves, which are in the present case designed separately from the control valves and the fluid connection between the valves and the supply channels shown. Also shown is the water cooling, consisting of feed nozzle 11 and passage channels 4 and 5 such that along the main axis of the oxygen lance the water is first led all the lance tube along to the burner tip 1 and then out of the burner tip 1 opposite out again.

The burner tip 1 is fastened by a plug connection to the lance tube 2 and has a funnel-shaped depression, which tapers from the reactor-side end of the burner tip to the lower-lying mouth of the feed tube for fuel I. The burner tip is designed so that the cooling water channel, which spends the water from the side facing away from the reactor to the burner tip is fluidly connected to the cooling water channel, which carries the water in the opposite direction. This is done by a corresponding design of the burner tip by small, with the cooling water channels in the plugged state tightly closing channels with channel walls 31, 32nd

Fig. 3 shows an embodiment of a control device according to the invention, which is realized by two parallel-connected in the oxygen flow valves IV and V and also a valve VI for controlling the separate fuel supply.

From the shut-off valve 12, the oxygen flows into the left distributor and divides into a first and a second oxygen stream. The first oxygen flow is controlled in its flow rate from the valve for the fuel oxygen V, while the second oxygen flow in its quantity through the valve is determined for the reaction oxygen IV. After passing through the valves, the two oxygen streams reunite into a stream, which then leaves the control device. It can be dosed by the closing of the valve IV and the correspondingly wide openings of the valve V, the oxygen in the amount required for stoichiometric combustion in the pilot flame of the burner, which pressure must always be above the partial pressure in the high temperature reactor. To maintain the stoichiometric combustion ratio, therefore, the opening of the valve VI, which controls the supply of fuel gas, must be adjusted accordingly. Further oxygen which is to be supplied in a superstoichiometric amount with respect to the combustion in the pilot flame and thus to be introduced as a reactant into the gasification bed of the reactor can be added by opening the valve IV. The pulsating switching between the aforementioned first mode ("burner only") and the second mode ("burner and reaction oxygen supply") can be realized by pulsing opening and closing of the valve IV in the simplest way.

Claims (11)

1. Oxygen lance for high temperature gasification of if necessary thermally pre-treated heterogeneous wastes, having channels (I, II, III) for transporting reaction oxygen, for supplying fuel and for supplying combustion oxygen,
   characterised in that
   the channel for transporting reaction oxygen (III) is identical to the channel for supplying combustion oxygen (II) and a control device is included which controls the quantity of supplied oxygen in at least two different admission states.
2. Oxygen lance according to claim 1, characterised in that the control device has valves (IV, V) connected in parallel in the oxygen flow.
3. Oxygen lance according to one of the claims 1 or 2, characterised in that an exchangeable burner tip (1) is provided on the reactand discharge side.
4. Oxygen lance according to claim 3, characterised in that the burner tip (1) is secured by a plug-in or a screw connection (31, 32).
5. Oxygen lance according to one of the claims 1 to 4, characterised in that the channels (I, II) extend concentrically in the axial direction, one lying inside the other.
6. Oxygen lance according to one of the claims 1 to 5, characterised in that coolant channels (4, 5) are provided in addition.
7. Method for operating an oxygen lance according to one of the claims 1 to 6 in a high temperature reactor, wherein the oxygen lance is operated permanently with at least one burner flame, characterised in that

   - in a first operating mode, the reactands fuel and oxygen are supplied in an approximately stoichiometric ratio for the burner flame,

   - in a second operating mode, the oxygen is supplied in a hyperstoichiometric ratio to the fuel so that this proportion of the oxygen proceeds into the high temperature reactor as a reaction partner,

   the pressure of the oxygen always being chosen such that it is greater than the partial pressure in the high temperature reactor.
8. Method according to claim 7, characterised in that a pulsed switch-over takes place between the first operating mode and the second operating mode.
9. Method according to one of the claims 7 or 8, characterised in that methane gas is selected as fuel.
10. Method according to one of the claims 7 or 8, characterised in that synthesis gas produced in the process or individual components of the same are selected as fuel.
11. Method according to one of the claims 7 or 8, characterised in that liquid and/or pumpable, pollutant-containing substances are selected as fuel.

Images