METHOD AND REACTORS FOR GASIFICATION OF FUELS IN THE FORM OF DUST, SOLIDS, OR LIQUIDS, SUCH AS COAL, PETROLEUM COKE, OIL, TAR, OR THE LIKE

Description

The invention is directed at a method for cooling units subjected to stress at high temperatures, in cooled reactors for gasification of fuels that contain carbon, using gasification media that contain oxygen, whereby the reactor walls are cooled by way of a coolant circuit.

Gasification processes in corresponding reactors take place at high temperatures. In order to protect the surroundings from exit of the heat flows, it is known to cool the reactor walls by means of a corresponding main cooling system. Since installations are provided in the reactors, it is important to cool these accordingly, as well, and to set them to a temperature level with which a long useful lifetime of these parts is achieved. This can involve a gasifier, a burner, or the like, for example.

From EP 0 986 622 B1, it is known to cool a burner that projects into the gasifier by way of an independent cooling circuit, whereby the coolant that comes from a source vessel is passed back to the source vessel after the burner has been cooled and after a corresponding heat emission has taken place by way of the heat exchanger. A feed line for nitrogen is present at the source vessel, as is an outlet to the flare, which is connected with the gasifier by way of a pressure regulation device. The status in the source vessel is also recorded and regulated. A disadvantage of this known method of procedure consists in that if a leak occurs, not only CO or H₂, but also other components that are present in the produced gas, such as salts, hydrogen sulfide, and other elements, can enter into the cooling circuit, and these can lead to great difficulties in the cooling circuit. For example, particles can block the lines or lead to abrasions, chlorides can promote corrosion, and the like.

This is where the invention takes its start, whose goal consists in providing a corresponding cooling method that reliably prevents penetration of such substances into the cooling circuit.

This task is accomplished, according to the invention, in that the units to be cooled, such as, for example, gasification burners, burner muffles, or the like, are equipped with an independent cooling circuit, whereby this cooling circuit is directly connected with the main cooling circuit.

A number of advantages is achieved with the invention; in particular, it is possible to impose the pressure level of the main cooling circuit directly onto the secondary cooling circuit(s), whereby here, the invention provides that the unit cooling circuit, in each instance, is operated at the pressure level of the main cooling circuit.

In this connection, it can be provided, in a further embodiment, that the unit cooling circuit is connected with the equalization vessel (steam drum) of the main cooling circuit, in terms of effect.

A particular embodiment of the invention consists in that when a fluid loss occurs in the unit cooling circuit, additional feed from the main cooling circuit is provided. If, for example, a leak occurs in the unit cooling circuit, then the additional feed from the main cooling circuit can immediately be evaluated as a signal, which triggers a leak report.

An adjustment of the temperature of the cooling medium in the unit cooling circuit can take place in that an indirect heat exchange with feed water and boiler water and/or by means of mixtures of feed water and boiler water takes place, as the invention also provides.

In order to implement the method of procedure according to the invention and to accomplish the task formulated initially, the invention also provides a system having a main cooling circuit for the reactor for gasification of fuels that contain carbon, and having a steam drum integrated into the cooling circuit, which system is characterized by one or more unit cooling circuits for cooling units assigned to the reactor, such as gasification burners or the like, whereby the unit cooling circuit is connected with the steam drum of the main cooling circuit, in terms of effect, in such a manner that the pressure level of the main cooling circuit also prevails in the unit cooling circuit.

In this connection, it can be provided, in an embodiment, that a leak monitoring device is provided in a connection line between the unit cooling circuit and the main cooling circuit.

Further characteristics, details, and advantages of the invention are evident from the following description and using the drawing. This shows, in

FIG. 1 a basic circuit schematic of the system according to the invention,

FIG. 2 a circuit variant of the system according to the invention.

First of all, it should be noted that the system shown in the figures is a system for cooling or tempering surfaces that are subject to great temperature stress, for example the burner of a cooled reactor for gasification of fine-particle, liquid or solid fuels with gasification media that contain oxygen, which work at temperatures above the slag melting point, in ranges of 1200 to 2000° C., whereby the pressure amounts to 0.3 to 8 MPa, with one or more burners and one or more burner levels, whereby the corresponding reactor is not separately shown in the figures; only the entry and exit to the cooled membrane surfaces are shown.

In the example shown in FIG. 1, a unit cooling circuit, for example for cooling a gasification burner designated with 1, having a burner head 3, above the corresponding cooling surface 2, is shown, framed with dot-dash lines and designated with “A”, whereby further units to be cooled can be provided; the corresponding cooling surfaces are designated with 2a and 2b in the drawing. The coolant of the unit cooling circuit is passed in a circuit by way of a line 4, from the cooling surface 2 over a heat exchanger designated with 6, back to the cooling surface 2, by means of a pump 5.

The unit cooling circuit is passed with the steam drum 8 of the main cooling circuit designated with “B” by way of a connection line 7, whereby the inflow into the cooling surface of the main cooling circuit is designated with 9, the flow back to the steam drum 8 with 10; the boiler water circulation pump of the main cooling circuit “B” carries the reference symbol 11. In the unit cooling circuit from the connection line 7 to the steam drum 8, a leak monitoring device, designated with 12, is provided. If the pressure in the unit cooling circuit “A” drops, for example, coolant is automatically supplied from the main cooling circuit, and a leak alarm is triggered.

In FIG. 1, two temperature control systems “C” and “D” are shown, which can be used individually or in combination. The control system “C” consists of a TC element 13 as well as a feed valve 14.

The regulation device “D” can be provided to prevent boiling in the flow back from the heating or cooling surfaces of the unit cooling system; this device also consists of a TC element 15 and a valve 16.

FIG. 2 shows a circuit variant, whereby all the identical system parts bear the same reference symbol as in FIG. 1, if necessary supplemented with the letter “a”.

In contrast to what is shown in FIG. 1, here a new temperature control system “E” is introduced, having a corresponding TC element 13a and a feed valve 14a, which impacts a bypass line 17 that circumvents the heat exchanger 6. It is evident that corresponding temperature regulation can be undertaken by means of this bypass arrangement.

Of course, the exemplary embodiments of the invention described here can still be modified in many different respects without departing from the basic idea.