NO328487B1 - Process and apparatus for producing solid fuel, synthesis and reduction gas. - Google Patents

Description

The present invention relates to a method and a device for producing combustion, synthesis and reduction gas from productive and fossil fuels, other biomass, waste or sludge by combustion in a burner with the addition of gaseous oxygen and/or oxygen-containing gases in sub-stoichiometric conditions above the melting temperature for the inorganic portions of CO2- and H20-containing gasifiers.

The invention is intended preferably for pyrolysis products produced therefrom according to patent DE 44 04 673, whereby pyrolysis products, when these are used, before they are introduced into the reactor, are supplied to the reactor as much as possible in solid and gaseous products, e.g. smoldering combustion gas and charcoal, separated and separate.

The device according to the invention can find application in energy supply, chemical industry and metallurgy for highly efficient production of combustion, synthesis and reduction gas for power machines, synthesis processes, ore reduction and pig iron production.

There is a relatively large number of gasification methods which can mainly be assigned to the three big ones

groups of fixed bed, fluidized bed and jet stream gasification. With the devices for gasification and especially with the device for jet stream gasification to which the device according to the invention must be incorporated, many compromises have to be made based on energy considerations and the need for gasifiers. Flyge current gasification with melting of the mineral components mostly takes place in a one-stage process, which means that all the media that participate in the gasification reaction, to-

is fed into a reaction chamber. Thereby, all media are raised to the high level above the slag melting temperature for the mineral components in the fuels. This is the case with reactors as well as with a walled-up refractory and with a reactor wall covered with a cooling shield. In the case of reactors with a cooling screen, as is typical of the GSP jet stream reactor (see literature [1,2]), a significant proportion of the sensible heat of the gasification gas is dissipated by the cooled wall. In the case of direct current reactors with water quenching of the gasification gas to water vapor saturation temperature, with or without a cooled reactor wall, a very large amount of heat is also reduced to a low exergy level. In reactors with a cooled reactor inner wall but also in counterflow reactors where the gasification gas leaves the reactor upwards and the liquid slag downwards, the slag drain must be kept free with extra heat or even with extra burners. These precautions result in a high oxygen demand for reducing the heat value of the combustion gas and consequently low exergetic efficiency during the entire gasification. If these precautions are not taken, the function of a carburettor is disrupted, because the slag flow cannot be maintained.

Especially in jet stream reactors that are operated with oxygen, the reaction partners have very short residence times. In order to avoid an oxygen breakthrough in the event of a loss of fuel, measurement and monitoring are required to a very large extent.

Jet stream reactors that are fed by a separate pyrolysis with fuel have the disadvantage that the pyrolysis products are cooled before being fed into the reactor and, in addition to the heat losses, also require a very extensive gas treatment and handling of the liquid products.

As an example of background technology, US 3,840,354 should be cited, which includes a three-stage method for producing gas from carbonaceous material, and in particular the production of combustion gas rich in methane using elevated temperature and pressure.

The purpose of the invention is to propose a method and a reactor which, in relation to the state of the art, will operate at an average lower temperature level with a higher exergetic efficiency and produce a gasification gas which is free of hydrocarbons and chlorinated hydrocarbons (dioxins, furans) and which can be used as fuel gas for flow, as synthesis gas or as reduction gas in a heat with ore reduction.

This is achieved according to the invention with the distinctive features according to independent claims 1 and 13. The other non-independent claims 2-12 and 14-22 relate to embodiments of the invention.

The purpose is achieved by the reactor being constructed in such a way that the physical heat is maintained at a high temperature level with only minimal losses and is utilized to increase the chemically bound heat. Thereby, fuel and/or gas of combustion temperature is brought into rotation first at the burner exit or at the combustion chamber entrance, which causes hot slag droplets to be flung against the chamber wall and flow away along this to a slag trough at the bottom of the combustion chamber. The combustion chamber wall is thereby kept at such a temperature level that a layer of solidified slag melt is deposited on the wall with additional, overlying and draining slag and for this it is flushed by (reflected) gasification gas.

The bottom of the combustion chamber is equipped with a central opening through which the released gas from the slag droplets flows out as a diving jet and enters the jet stream carburettor. The slag which flows down along the chamber wall is collected in the trough which surrounds the opening and which is preferably equipped with radial drains, and flows parallel to the gas in the jet stream carburettor. The gas outlet is thereby designed as a channel, whereby the gasification gas is laminarized. This leads to good results. Firstly, the flowing away slag is accelerated towards the water bath at the foot of the carburettor, and secondly, the downward flowing gas in the carburettor is maintained for a relatively long time as a jet, whereby it de-brakes itself above the water bath due to densification effects and is deflected upwards ( is reflected) and then directed upwards parallel to the diving jet at the carburettor wall. In the downward-directed gas jet, the carbonaceous combustion dust is blown in under reducing conditions, is first carried downward and then reaches the mantle-shaped upwardly directed gas part, the dimensioning of the device and the flow rate being determined with a view to extensive gasification of the combustion dust.

A mantle of temperature-resistant steel or ceramic can be arranged around the gas outlet, in order to inhibit return mixing of the upward-flowing gas portion with the outgoing jet, through which fuel dust can be supplied through lances.

The upward-flowing gas is introduced, e.g. through a guide device, in a space between an outer casing of the device and the combustion chamber mantle, where it causes a heat equalization and leaves the device through the gasification gas outlet.

The device is equipped with a heat protection coating and preferably cooled.

The resulting gas is of high quality and can be used directly.

Before the upward-flowing gas enters the heat equalization channel, it can be quenched by injecting water or cold gas, e.g. in unstable operating conditions.

The invention is described in more detail below in connection with the accompanying drawing.

A combination burner 1 is used which receives hot, gaseous and smoldering products, including vapor-form components, such as tar, oil, water and dust through the inlet nozzle of the smoldering product channel 4 and guides these into the combustion chamber 9 by means of a screw movement device 33. In the combination burner's smoldering product channel, pipes are used for feeding residual coke, ash and aggregate 8 into the reactor, so that the mineral components that are to be melted in the combustion chamber 1 are thrown against the side wall of the combustion chamber 1 rotating, heated and in liquid form. For the sub-stoichiometric combustion of gasifier above the ash melting temperature, the combination burner 1 is equipped with additional supply channels for oxygen 7 or air 3 which, in the same way as the smoldering products, are introduced into the combustion chamber 1 by means of screw movement devices

33 for faster conversion with the combustion products to gasification agent and for melting the mineral components in the residual coke, the ash and possibly the aggregates. In order to

prevent critical heat introduction into uncooled structural parts, the ignition fuel supply 2, the ignition air supply 5 and the ignition device as well as the ignition monitoring 6, which are required for starting and heating, are built into the combination burner, where these elements are protected against other, flowing media during stationary gasification operation.

A known screw movement burner for carbon combustion dust can also be used.

Combustion chamber 9 is operated above the melting temperature for the mineral components of the residual coke, ash and aggregates. The wall in the combustion chamber 9 is heat-conducting so that towards this slag runs to a protective layer according to heat dissipation solidified outwards and above that liquid slag due to the temperature in the combustion chamber 9. The bottom of the reaction room 10 is designed with a slag collection trough with integrated drainage channels 12, so that a slag bath 13 can be formed, which due to the direct contact between the slag and the gasifier 11 and through the direct current with the gasifier 11 also always ensures the flow of the slag through the gas outlet 34. The gasifier 11 which under gasification conditions develops substoichiometrically in the combustion chamber 9, serves due to its highly set CO2 and I^O content as gasification agent in the endothermic jet stream gasifier 14. The sensible heat introduced by the gasification agent 11 is used to cover the endothermic gasification reaction between fuel dust and gasification agent. For that reason, lances 15, 17 are arranged for the combustion dust in the reactor. The gasification agent 11 enters as a diving jet 16 in the endothermic suspended-flow gasifier 14 and accelerates the entrained slag droplets 18, so that they, introduced into the water bath 19, solidify into elution-resistant granules. The slag outlet 22, the water inlet 21 and the overflow 20 are arranged for media removal and replenishment of evaporated water. They form, together with the water bath 19, the lower end of the endothermic jet flow reactor 14.

Furthermore, the diving jet can be stabilized and a return mixing with the reflected gas which flows upward parallel to the chamber wall in a mantle form, inhibited by arranging, below the gas outlet 34, a mantle 35 of heat-resistant steel or ceramic where the continuous combustion dust lances 15 are introduced. Additional lances 17 may be located below the others.

The constructed construction ensures, by the supply of oxygen-free gasification agent 11 and to gasifying combustion dust in the endothermic suspended-flow reactor 14 and, through the high gasification temperature above 500°C, that no oxygen breakthrough can enter cold reactor areas.

For heating the gasification gas 23 which has been cooled by the endothermic gasification, the heat equalization channel 26 with optionally installed guiding devices 24 serves. itself a protective layer of solidified slag. In addition, the cooling of the combustion chamber wall increases with the help of the cooling device 27 which is supplied through coolant inlets and outlets 28 and 29. To lower the gasification temperature, which should be between 500 and 1,200°C, a device 30 is arranged for rapid cooling of the gasification gas and with mounted cooling nozzles 31. Through the refractory-lined gasification gas outlet 25, the gasification gas leaves the reactor.

With further design of the multi-stage reactor, a significantly expanded use of the reactor is made possible. Thus, by replacing the residual coke/ash and combustion dust lances 8, 15 and 17 of parts of the combination burner and the cooling nozzles 31, opportunities can be created for foreign mineral, potentially contaminated substances but also ore, melting and gasification of foreign fine-grained fuels, own combustion gas or to use foreign transport gas for dosing or for cooling with different media such as water, steam or cold gas.

Consideration has also been given to the design of a trough for collecting the melt that flows from the combustion chamber 9 in liquid form, which instead of the water bath 19 then forms the lower end of the endothermic fly stream gasifier 14.

For chemical and thermal protection, the reactor is provided with a refractory delivery 32. However, it is also designed with heat-resistant, corrosion-resistant material and thermal outer insulation for pressures up to 10 MPa.

To protect against a breakthrough of the combustion chamber 9 in the endothermic jet stream carburettor 14, the lower part of the heat equalization channel 26 is designed conically.

Literature:

[1] CARL/FRITZ: "NOELL CONVERSION PROCEDURE" EF-Verlaug fur Energie- und Umwelttechnik GmbH, 1994.

[2] LUCAS et al: "Ein Vergleich von Kohlevergasungs-verfahren unter Druck in der Flugstaubwolke" Chemische Technik, 1988, hefte 7, p 277-282.

Reference character list

Claims (22)

1. Process for the production of combustion, synthesis and reduction gas from reproductive and fossil fuels, other biomass, waste or sludge by combustion in a burner (1) with the addition of gaseous oxygen and/or oxygen-containing gases in sub-stoichiometric conditions above the melting temperature of the inorganic proportions of CC^- and H20-containing gasifiers, characterized by that When fuel and/or gas flows into a combustion chamber (9), rotation is applied and the liquid, mineral components are flung against a largely vertically arranged burner wall and are separated from the resulting gasification agent, the gasification agent is led through a central opening in the bottom of the combustion chamber (9) in a gasification reactor and thereby forms a diving jet, the separated volatile components are led away through the central opening at the bottom of the combustion chamber (9) and thereby entrained as slag droplets by the gasifier diving jet and accelerated towards the reactor bottom, where they are collected and diverted by it, where in the gasifier (14) carbonaceous combustion dust is added to the gasification agent, carbon dioxide being reduced to carbon monoxide and water vapor to hydrogen during the ongoing gasification reaction, and the gas diving jet (16) is deflected above the reactor bottom and the produced gasification gas in the upper part of the reactor is diverted and stored for combustion, synthesis or reduction gas during subsequent dedusting and chemical cleaning. 2. Method in accordance with claim 1, characterized in that the allotherm or autotherm fuels are heated from 300 to 800°C whereby the products before being fed to the combustion chamber (9) in gaseous and solid carbonaceous fuels e.g. combustion gas and charcoal are supplied separately and separately and in connection with the method. 3. Method in accordance with claim 1 or 2, characterized in that the solid carbonaceous fuels are ground into combustion dust. 4. Method in accordance with claims 1 to 3, characterized in that part of the burner's (1) heat requirement is covered by heat exchange with the gasification gas and/or the combustion, synthesis or reduction gas. 5. Method in accordance with claim 4, characterized in that the combustion gas is led through the space between the reactor wall and an outer combustion chamber wall and absorbs part of the heat to be dissipated from the combustion chamber. 6. Method in accordance with claim 5 or 6, characterized in that the hot gasification gas is cooled before flowing into the space or in the space between the reactor wall and the outermost combustion chamber wall. 7. Method in accordance with one of claims 1 to 6, characterized in that the slag is collected in a water bath on the reactor bottom and diverted from there. 8. Method in accordance with claim 6, characterized in that the cooling takes place directly by quenching with water, water vapor and/or cold gas or by means of a cooling surface which is connected to the reactor wall or their walls. 9. Method in accordance with one of claims 1 to 8, characterized in that additional mineral substances and/or ore are added and, upon burning, are melted into the carbonaceous solid fuels. 10. Method in accordance with one of claims 3-9, characterized in that foreign fine-grained fuels are added to the combustion dust. 11. Method in accordance with one of claims 1-10, characterized in that the combustion dust is blown through one or more lances into the diving jet, preferably immediately below the bottom of the combustion chamber. 12. Method in accordance with one of the claims 1-11, characterized in that the slag is collected in a slag collecting trough at the bottom of the combustion chamber and fed to the central opening through drainage channels. 13. Device for carrying out the method according to one of the claims 1-12, consisting of a combination burner (1) and a combustion chamber (9) arranged below with supplies of fuel and gas (2, 3, 4, 5, 7, 8), characterized by) that at the foot of the combustion chamber (9) there is arranged a screw movement device (33) over which the fuels and gases from the combination burner (1) are led downwards to a gas outlet (34) in the middle of the bottom, b) that the gas outlet at its upper end is enclosed by a slag trough (12), c) that below the gas outlet (34) there is an endothermic fly stream gasifier (14) with a slag trough (19) and a slag outlet (22), and d) that below the gas outlet (34) there is arranged combustion dust lances (15) projecting into the carburettor (14). 14. Device in accordance with claim 13, characterized in that the gas outlet (34) is enclosed by a mantle (35) of temperature-resistant material 15. Device in accordance with claim 13 or 14, characterized in that upper (15) and lower fuel lances (17) are arranged, of which the upper (15) are led through the mantle (35). 16. Device according to one of the claims 13-15, characterized in that the endothermic fly-stream carburettor (14) is surrounded by a heat protection cladding (32). 17. Device according to one of the claims 13-16, characterized in that the heat protection cladding surrounds the combustion chamber (9) at a distance while forming a heat compensation channel (26) in the form of an annular chamber. 18. Device according to one of claims 13-17, characterized in that the heat protection cladding (32) is provided with a cooling device (27) in the zone by the combustion chamber (9). 19. Device in accordance with one of claims 13-18, characterized in that guiding devices (24) are arranged in the annular chamber or the heat equalization channel (26). 20. Device in accordance with one of the claims 13-19, characterized in that quench devices (30) are arranged in the upper zone of the endothermic fly stream gasifier (14) and/or in the heat equalization channel. 21. Device in accordance with one of claims 13-20, characterized in that the slag trough (12) is designed cone-shaped and with drainage channels for the slag. 22. Device in accordance with one of claims 13-21, characterized in that the bottom of the combustion chamber (9) is made cone-shaped and the jet stream carburettor (14) as a breakthrough protection comprises a counter-cone which surrounds the bottom of the combustion chamber at a distance.