KR102054353B1 - Process and device for fixed-bed pressure gasification of solid fuels - Google Patents

Abstract

The present invention relates to a process and apparatus for fixed-bed pressure gasification of solid fuels with increased performance and extended use spectrum of solid fuels. To this end, the process includes a supply of prefabricated solid fuel, a gas outlet having both a rotating grid on top of the fixed-bed pressure gasifier and a re-discharge at the bottom of the fixed-bed pressure gasifier, a fixed-bed pressure gasifier In a manner using a fixed-bed pressure gasifier with an adjustable supply for the first gasifier for non-slag gasification using a rotating grid of At least one extending into the upper region of the fixed-bed pile, wherein the second gasifying agent for slagging gasification is in addition to the first gasifying agent supplied using the rotating grid; Of gasification agent is injected through the nozzle.

Description

PROCESS AND DEVICE FOR FIXED-BED PRESSURE GASIFICATION OF SOLID FUELS}

The present invention is directed to a process and apparatus for fixed-bed pressure gasification of solid fuels with increased performance and extended use spectrum of solid fuels. The process and apparatus according to the invention allows the gasification of fine-grained and pulverized fuels by the gasification and / or addition of coal having a high fine grain component.

The gasification of coarse-grained solid fuels, ie coarse coal and / or carbonaceous solids, having a grain size larger than about 5 mm and smaller than about 10 mm, is preferably fixed bed dry gasification. It is carried out on a fixed bed by a process of fixed-bed pressure gasification, also known as Bottom Gasification. Fuel is introduced into the fixed-bed pressure gasifier above the head by a pressure lock. In a fixed bed (actually moving bed) that extends above the height of a fixed-bed pressure gasifier, the following zones are used: drying zone, pyrolysis zone, gasification zone, oxidation zone, and ash zone. This is formed in an ideal-typical manner from top to bottom. At the bottom of the gasifier, the ash is discharged through a rotating grate which simultaneously acts to feed the gasification medium. A source gas draw is located on top of the fixed-bed pressure gasifier.

The gasification medium consists essentially of technical oxygen and steam. Steam limits the maximum temperature in the oxidation zone below or near the remelting temperature associated with fixed-bed pressure gasification and thus also results in the formation of large interfering agglomerates or slagging (non-slag gasification). To avoid formation, it is added excessively. The quantity ratio of steam and oxygen in the gasification medium represents one of the most important quantities for control of the process. It is often expressed in the steam / oxygen ratio, preferably in unit kg steam / m _std ³ oxygen (100% by weight). Depending on the height of the remelting temperature, about 4 kg / m 3 (high-melt ash) and about 9 kg / m 3 (low-melt ash) are required. Excess steam increases the gas flow rate and the amount of fines discharged with the source gas through the source gas outlet, but does not contribute to an increase in reaction turnover. The value for the steam / oxygen ratio is adapted to the remelting temperature and also kept as low as possible (so-called critical minimum of steam / oxygen ratio for "hot" operation at the "slag limit"). First and foremost, there are significant limitations on maximum performance, bed permeability, and dust emissions [J. Schmalfeld: Die Veredlung und Umwandlung von Kohle, DGMK (2008), p. 311].

The general disadvantage of fixed-bed pressure gasification that is caused is that the solid fuel to be gasified has only a small amount of fine fuel having a grain size of less than about 5 mm and especially a powdered fuel having a grain size of less than about 1 mm. It consists of what should be included. Otherwise, this results in the local accumulation of fine material in the fixed bed as a result of high emissions of dust, incomplete carbon conversion of ash or slagging as well as non-regular channeled flow through the fixed bed. . These negative effects are reinforced in different ways when caking hard coal or briquetted lignite is used.

A general disadvantage of the backflow principle is the additional application of the low source gas outlet temperature of fixed-bed pressure gasification. Ammonia, non-condensable higher hydrocarbons, phenols, and tar oils released with dust are generally separated into water (tar / gas water / dust mixtures), which is an undesirable dispersion. The source gas outlet temperature is obtained according to the feed fuel corresponding to the overall thermal equilibrium of the process. Except for incomplete heat exchange between gas and solids (eg lowered beds), which are optionally arranged, they cannot be actively increased.

In order to maintain the required grain size spectrum of the prefabricated fuel to be gasified, the raw coal must be processed. In particular, hard coal is screened and / or washed before gasification to separate fines (coal fines), lower ash content and also increase the quality of the solid fuel to be gasified. Fines smaller than 5 mm often reach up to 50% of unfiltered coal mined. A corresponding solution is desired because the separated coal fines cannot be readily used for the production of syngas during fixed-bed pressure gasification.

According to EP 10792A1, pellets were formed from fine fuel, which is surrounded by a non-caking enveloping layer. GB 1435089A is a fine coal / ash / pitch that is processed in an extruder to obtain an extrudate and is compressed directly from the extruder into the free gas space of a fixed-bed pressure gasifier operated in the atmosphere. Production of the mixture is started. Pelletization aids for coal fine bentonite have been proposed (US Pat. No. 4,773,919 B1). Alternatively, US 4,146,369 B1 provides for inflation of a fixed-bed pressure gasifier upwards by a fixed-bed gasifier and equally up by an entrained-flow gasifier, wherein the fines Molded and powdered fuels can be used. In addition, the separation of gasification of fuel / hydrocarbon / water slurries already produced in powder-bed or conveying-flow gasifiers and for example in conveying-flow gasifiers in WO 1980/00974 A1 for processing fine or powdered fuels. Deployment is proposed.

DD 219 597 A1 discloses a process for non-slag gasification of coal, where the supply of gasification medium branches to primary and secondary supply. At a freely selected bed height adjusted to the material to be gasified, the major part of the gasification medium is fed to the primary gasification separated from the grate, and the part to be gasified which is provided for the secondary gasification is fed through the grate in a known manner and steam The oxygen / oxygen ratio can be reduced by the exclusive injection of steam. In general, this is a non-slag process of gasification by the formation of fine grained ash. According to the proposal, the gasifier must be operated at a high steam / oxygen ratio so as not to exceed the remelting point. The reason is to avoid slagging of gasifiers. In general, the fine ash component must be rapidly transported into the area below the gasification medium outlet to avoid re-transmission into the upper reactor section and discharge of ash with production gas. It should be recognized that this proposal ignores the basic requirements of environmental protection, efficiency and operational safety. In the non-slagging operation of the gasifier, the major that completes the supply of the gasification medium into the high area of the bed is essentially oxygen that has not been completely reacted with the source gas and combustion (channel breakthrough) through the bed. As this leads to a mixture of, deflagration or explosion can occur with catastrophic consequences. Another reason for the unfeasibility of the proposal is the incompleteness of the carbon conversion, i.e. the prevention of the high carbon content of the ash recovered through the rotating grate, and the suitability of the ash for landfill removal.

Another procedural limitation of non-slag fixed-bed gasification according to the prior art relates to the fuel spectrum for the caking capability of coal. However, hard coal with stronger caking properties requires a mechanical stirrer in the upper part of the fixed-bed pressure gasifier, which makes the process more complex, prone to failure, and more expensive as a whole.

Until now it has not been possible to find a more advantageous solution procedurally for the omission of agitators. Other proposed solutions for the use of fine fuels are technically expensive and not economically viable. They could not actually get permission. Differential fuel must be supplied for other uses (generally, combustion) instead of gasification. Nevertheless, most of the coal is often not economically useful and must also accumulate in the form of heaps.

Accordingly, it is an object of the present invention to develop a process for fixed-bed pressure gasifiers with related apparatus, which is characterized by small procedural and technical changes compared to the known fixed-bed pressure gasifiers. Increase the use of steam, lower the use of steam, broaden the spectrum of use of fuel for caking coal and coal with higher fines, and / or allow gasification of fine and powdered fuels.

According to the invention, this aim is that the minimum threshold for the steam / oxygen ratio can be adjusted to a pile of fixed beds on the rotating grate, and the feed for the assembled solid fuel, rotating on top of the fixed-bed pressure gasifier A gas draw having both ash and discharge at the bottom of the fixed and bed pressure gasifiers, with an adjustable supply for the first gasification medium for non-slag gasification by rotating grate of a fixed-bed pressure gasifier A process for fixed-bed pressure gasification of a prefabricated solid fuel into an oxygen- and steam-containing gasification medium by a fixed-bed pressure gasifier,

In addition and independently of the first gasification medium supplied by the rotating grate, a second gasification medium for slagging gasification is injected through at least one gasification medium nozzle reaching into the upper region of the fixed-bed pile;

The second gasification medium is solved by a process for fixed-bed pressure gasification which is injected at a steam / oxygen ratio of 0.5 to 4 kg / m ^{3 and} at a gas discharge rate of 20 to 120 m / s.

According to the invention, the second gasification medium for slagging gasification is supplied to the fixed-bed pressure gasifier in addition to and independently of the first gasification medium supplied via the rotating grate for non-slag gasification. The two gasification media are injected into the upper region of the heap of fixed beds by the gasification medium nozzles reaching into the upper region of the fixed-bed pile. With the first gasification medium, the entire mass of the bed fixed with the first non-slag gasification with an ideal-typical formation of the zone (first drying zone, first pyrolysis zone, first gasification zone, first oxidation zone) , Second slagging gasification with localized formation of a turbulent zone (raceway formation) by means of a second gasification medium.

The minimum threshold for the steam / oxygen ratio [expressed in kg of steam / m _std ³ oxygen (100% by volume) of the first gasification medium for "hot" operation at the "slag limit" is the solid fuel used. Is adapted to the remelting behavior. In short, adaptation is carried out so that significantly formed ash granulation is carried out (softening and sintering of the ashes) without the generation of large slag lumps that block the generation and release of slagging [cf. / J. Schmalfeld: Die Veredlung und Umwandlung von Kohle, DGMK (2008, p. 311 /.].

Advantageously, the second gasification medium is injected into the upper half of the first gasification zone formed during gasification, ie down the first pyrolysis zone formed during gasification. Particularly advantageous is the injection of the second gasification medium into the height zone below the pyrolysis zone which comprises a vertical extension of <1 m in the upper half of the first gasification zone. Particularly advantageously, the second gasification medium is from 1 m above the tip of the rotating grate to 0.5 m below the surface of the pile of the fixed bed, preferably from 2 m above the tip of the rotating grate below the surface of the pile of the fixed bed. It is injected into the height zone of a fixed-bed pressure gasifier extending at a maximum of 1 m.

According to an advantageous aspect of the process of the invention, the amount of injected oxygen of the second gasification medium corresponds to 0 to 50% of the total amount of oxygen supplied.

Injection of the second gasification medium with a gas discharge rate of 20 to 120 m / s is carried out in the form of a cavity in a fixed-bed pile before the nozzle outlet opening of the gasification medium in which carbon is burned with oxygen (second combustion zone). Causes formation. The turbulent zone in front of the nozzle is surrounded by excess steam of the first non-slag gasification and possibly a bunch of coke in which the steam of the second slagging gasification reacts with a decrease in temperature (second gasification zone ).

Due to the fact that the second gasification medium is injected at a steam / oxygen ratio having a value of 0.5 kg / _std ³ to 4 kg / _std ³ , preferably 0.5 kg / _std ³ to 3 kg / _std ³ , Ash released in front of the at least one gasification medium nozzle reaching into the upper zone immediately melts or sinters and also accumulates in the coke heap at the edge of the turbulent zone (second slag zone). The molten or sintered ash cools rapidly and solidifies to a surrounding cold coke heap and also releases its heat to the surroundings to reinforce the endothermic second gasification process. The formation of traditional layer-shaped zones does not occur during gasification with the second gasification medium.

For example, with a second gasification medium having a steam / oxygen ratio of 0.5, an average maximum temperature of about 2000 ° C. is achieved in front of the gasification medium nozzles reaching into the fixed-bed pile, which results in a remelting point of 1500-1700 ° C. It is advantageous for gasification of coal having. When the steam / oxygen ratio of the second gasification medium is 3.0, an average maximum temperature of about 1800 ° C. is achieved before the gasification medium nozzles reaching into the fixed-bed pile. This is advantageous for the gasification of coal having a remelting point of 1300-1500 ° C.

It is advantageous when gasification with the second gasification medium takes place under the first pyrolysis zone. Degassed coke is useful here (higher cooling gas efficiency compared to coal) and it is also ensured that the slag or sinter formed quickly solidifies into the surrounding cold coke heap. On the other hand, as described below, the ambient temperature of about 800 to 1100 ° C. around the periphery of the gasification medium nozzle reaching into the fixed-bed pile is so high that the solidified slag still does not achieve high strength. The slag that is stuck to the gasification medium nozzle is separated from the heap moving downwards and forwarded further.

With regard to the temperature of the coke heap in the first gasification zone, the following should be mentioned. That is, due to the endothermic gasification reaction (not initially considering the second gasification process), the temperature of the coke heap is settled to a constant value of approximately the so-called kinetic reaction end temperature. These values are automatically and cheaply obtained depending on the reactivity of the coke to steam. The range of reaction end temperatures ranges from about 800 ° C. with high-reactive fuels (eg, ortho-lignite) to low-reactive fuels (eg, low-volatile bituminous hard coal). By about 1100 degreeC. Thus, it lies below the temperature range for the remelting point of most fuels (about 1200-1500 ° C.).

The ash released during the second slagging gasification immediately melts and also suppresses each channeling, because the immediate formation of slag prevents the channel-like “burn-through” of oxygen through the heap. This is especially advantageous. Initially formed channels or channels resulting from the first gasification are likewise quickly "closed" by forming slag. For this reason, the turbulent zone cannot be removed from the gasification medium nozzles towards the top or only to a small extent, but is tortuous at about the same height in front of and above the gasification medium nozzles. Thus, the second gasification is locally limited and also limited to the height corresponding to the arrangement of the outlet openings of the gasification medium nozzle. The serpentine gas flow and the formed slag stabilize the fixed bed around and above the gasification medium nozzle, so that regular flow through the fixed bed is maintained despite the high flow rate.

Second slagging gasification leads to uniformity of flow through the entire fixed bed. The fine-grained component of the prefabricated fuel used can be increased without the release of dust with raw gas rise. The bottom grain size of the prefabricated solid fuel fed to the fixed-bed pressure gasifier at the top can be lowered from about 5 mm to about 2 mm.

Due to the gasification by the second gasification medium for slagging gasification, fine or powdered fuel (pulverized fuel) can be used in large quantities in addition to the prefabricated fuel, which otherwise must be supplied for other use or dumping. do. To this end, the fine fuel is introduced in a condensed form into the turbulent zone, and in any case the amount of added fine fuel is so large that in stoichiometric terms the substantial gasification of the turbulent zone is ensured.

Another essential advantage of the second slagging gasification consists in that the fine and powdered portions of the fuel are gasified in the turbulent zone, in particular by producing coarser ash / slag particles. The cooled, solidified slag contributes to increasing grain size in the entire fixed bed, especially in the first ash zone, and further contributes to the "interlocking" stabilization of the fixed bed over the entire height. Local accumulation of fines and dust is suppressed or delayed, which causes an explosive flow through the bed and is also one of the main causes for high emissions of dust. Thus, the second gasification leads to uniformity of flow through the entire fixed bed. The fine grain component of the spent fuel can be increased without the release of dust with rising source gas.

Drying to the moist, flowable fine fuel is advantageously charged approximately vertically above the turbulent zone formed in front of the gasification medium nozzle, into a heap of fixed beds from above by gravity. On gravitational input, the fuel, due to its own weight, slides into the gasifier from a pressure lock disposed above the fixed-bed pressure gasifier via a dosing device. However, it is also possible to enter pressure or gravity input directly over the turbulent zone from the side into the fixed bed. In addition, the dry fine fuel, which can be pneumatically conveyed, is blown directly into the turbulent zone through the gasification medium nozzle or by pneumatic transfer from the side. Finally, the finely divided fuel in the form of slurry is pumped over the turbulent zone via a so-called gasification medium nozzle or approximately vertically from above onto a fixed bed or into a fixed bed.

Alternatively, the use of a stuffing input is possible, which is carried out at the upper edge of the fixed bed, preferably in the first drying zone. By a briquetting press, preferably a stamp press, the fine and / or powdered fuel (fine fuel) is compressed, partially agglomerated or compacted in the forming channel, and also directly into the bed. Is pressed. In contrast to the teaching of GB 1435089A, the densified fine fuel does not fall from above onto a fixed bed, thereby avoiding the collapse of the densified fine fuel, which is followed by increased emissions of source gas dust. At the same time, the inlet strand of the densified fine fuel is covered upward by the assembled fuel, thus preventing direct blow out of abrasion. Another essential advantage of this input system is the possible mixing of the tar-oil solid mixture obtained as agglomeration aid during fixed-bed pressure gasification and possible omission of the lock system for input of fine fuel. Due to the very high densification pressures up to 150 MPa occurring in the forming channels, a nearly gas-tight closure between the pressurized gasification space and the surroundings is possible under atmospheric pressure, so that the separate pressurization system of the fine fuel can be omitted. This type of input of fine fuel is independent of the operation of the second gasification and can also be used as a non-operated or unused second gasification medium nozzle.

The second slagging gasification not only improves the fuel tolerance for increased particulate and dust components of the fuel or provides additional input of fine fuel, but it also increases the fuel tolerance for coking coal, which It cannot be gasified without the use of a stirrer. The second gasification zone with its rapid temperature rise and its high temperature reduces the caking formation of coal and also destroys the coke bonds already formed. Due to the second slagging gasification, the use of the stirrer can be omitted in many cases.

It is also possible to effect the second slagging gasification in the first pyrolysis zone or in the region of the transition from the first pyrolysis zone to the first non-slag gasification zone. In this case, the ratio of the combustion and gasification reaction is further shifted in the direction of the combustion reaction in the second slagging combustion zone. The higher hydrocarbons, phenol, as well as the tar oil leaving the raw gas outlet temperature rise and leaving the bed fixed upwards, are thermally more strongly destroyed. Zone-related adjustment of the second slagging gasification is achieved by setting a defined bed height of a fixed bed. In this way, the source gas outlet temperature and the quality of the source gas (methane component, unwanted secondary component, etc.) can be adapted.

The gasification medium nozzle is designed as a water-cooled gasification medium mixture nozzle (in the case of oxygen and steam as the second gasification medium) or as a water-cooled multipart nozzle (in the case of a combined supply of fine fuel). They can be formed non-cranked (turbulent nozzles) and cranked (crank nozzles), in the case of crank nozzles, the cranked nozzle head is seated on a turbulent nozzle shank. do.

The gasification medium nozzle is guided through the cylindrical outer jacket or double jacket of the fixed-bed pressure gasifier. Non-cranked gasification media nozzles are different from radial and horizontal alignments that are aligned radially and horizontally or attachable in all directions at an angle of attack of <45 °. Preferably, the nozzles are aligned radially and are also inclined downwards from 10 to 20 degrees with respect to the horizontal line. This has been found to be advantageous for the avoidance of the inflow of solids into the interior of the nozzle and also for the formation of turbulent flow zones. In the case of the use of a cranked gasification medium nozzle, the nozzle shanks are aligned approximately horizontally, and the nozzle head is similar to the aforementioned angle of incidence of the tubular nozzle.

The second slagging gasification is carried out with a restricted height zone in the upper region of the bed of the fixed-bed pressure gasifier. The lower limit is given by the fact that a sufficiently large vertical minimum distance for the underlying oxidation zone is ensured. This distance is> 0.5 m, preferably> 1 m. The vertical minimum distance to the tip of the rotating grate is therefore> 1 m, preferably> 2 m. Before it enters the oxidation zone or on the surface of the rotating grate, it is required to allow the slag or sinter formed in the turbulent zone to solidify. On the other hand, the gasification medium nozzle is not exposed to too high a temperature (<1100 ° C.) in the gasification zone. The upper limit of the height zone is due to the fact that a sufficiently large overlap of the gasification medium nozzle is ensured by the fuel bed of the fixed bed of> 0.5 m, preferably> 1 m. With the bed height of the fixed bed of 5 m calculated from the tip of the rotating great, the vertical extension of the height zone for the second gasification can reach up to 3.5 m, preferably up to 2 m. The gasification medium nozzle may be distributed above this height and above the cross section of the fixed-bed pressure gasifier.

Another advantageous aspect is that a rather short height zone with a vertical extension of <1 m in the upper half of the first gasification zone below the pyrolysis zone for the second slagging gasification zone is selected so that the first non-slag gasification zone is selected. It is configured to extend upwardly uniformly over the cross section.

Alternatively, if the height of the heap of the fixed bed varies between the maximum and minimum levels during operation of the fixed-bed pressure gasifier and the difference is greater than 1 m, alternatively two height zones of the fixed-bed pressure gasifier When equipped with this gasification medium nozzle, the lower height zone for the minimum level and the upper height zone for the maximum level of the fixed bed are advantageous. The vertical minimum distance of the two height zones is greater than 1 m. In procedural terms, the two height zones are then optionally filled with a second gasification medium.

 Advantageously, the second gasification medium is sprayed from the height zone into a flat horizontal plane, in a vertical stepped arrangement or from a cone-shaped height zone that approximately regenerates the contours of a mushroom-shaped contour or bed surface of a rotating great. do.

Preferably, the nozzle orifice of the gasification medium nozzle is in the height zone in a flat horizontal plane in the height zone, in a vertical stepped arrangement or in a cone-shaped height zone that approximately regenerates the contours of the mushroom-shaped contours or bed surfaces of the rotating greats. Is located in.

With a free length (free nozzle length) of at least 10 cm, the gasification medium nozzles project into the gasification space of the fixed-bed pressure gasifier. Preferably, the gasification medium nozzle located close to the wall protrudes about 20 cm to 1 m into the gasification space of the fixed-bed pressure gasifier. With a large free nozzle length of up to about 3 m, the gasification medium nozzle is held from above by a tie rod.

In order to form turbulent zones that are locally separated from each other, the transverse horizontal distance between the outlet openings of the gasification medium nozzles should not fall below 50 cm. Preferably the lateral horizontal distance of the exit opening is between 1 and 2 m. The vertical distance of the exit opening, the one above which the other is located, should be at least 1 m, but preferably greater than 2 m.

The second gasification medium is injected at a steam / oxygen ratio of 0.5 to 4 kg / m ³ , preferably 0.5 to 3 kg / m ³ . Although steam is not required from a procedural point of view, small mixing of steam is advantageous, so when oxygen is quickly shut off, steam is useful as a purge gas for the gasification medium nozzle without interruption. Instead of steam, carbon dioxide or other inert gas may be used as the purge gas.

The ratio of the amount of the second oxygen to the first oxygen can vary with wide limits. In the case of individual gasification medium nozzles, 5 to 20% by weight of the total oxygen supplied is injected as the second oxygen. In addition, the upper limit may be exceeded when a large amount of fine fuel is used with a gasification medium nozzle. In the case of the formation of a second gasification zone over the entire cross section of the fixed-bed pressure gasifier and further gasification of the fine fuel, up to 50% by weight of the total oxygen supplied can be injected as the second oxygen. The lower the ash content of the feed fuel, the greater the amount of second oxygen can be achieved.

The size of the slag or sintered member formed in the turbulent zone in front of the individual gasification medium nozzles is limited by the fact that the oxygen load of the individual gasification medium nozzles varies between minimum and maximum loads. The total amount of oxygen in the second gasification medium can be kept constant in the load distribution between the individual nozzles, or the total amount of oxygen can also change over time.

Corresponding to the ratio of the amount of injected second oxygen (for slagging gasification) in addition to the first oxygen (for non-slag gasification), the heat capacity of the fixed-bed pressure gasification increases approximately proportionally. It is not important that the fuel throughput is increased or that additional fine fuel is introduced. In conjunction with or in addition to the prefabricated fuel, large amounts of fine or fine fuel may be gasified. In addition, the fuel spectrum can be expanded more strongly in the direction of hard coal caking without requiring the use of an agitator. At the same time, the specific use of steam is lowered, and the performance limitations of the heat gasifier capacity are also increased due to the improved flow conditions of the heap of fixed beds.

According to the invention, the object is to provide a feed of prefabricated solid fuel, a raw gas draw, fixed-bed pressure gas having both a rotary grate on top of a fixed-bed pressure gasifier and a re-discharge at the bottom of a fixed bed pressure gasifier By means of a fixed-bed pressure gasifier for gasifying prefabricated solid fuel with an oxygen- and steam-containing gasification medium with an adjustable supply for the first gasification medium for non-slag gasification by means of the rotary great of the firearm. Solved, the minimum threshold for steam / oxygen ratio is adjustable with a pile of fixed beds above the rotating grate, and a fixed-bed pressure gasifier at the level of the upper region of the fixed bed piles for non-slag gasification At least one projecting into the upper region for additional and independent supply of the second gasification medium relative to the first gasification medium A gasification medium nozzle, the at least one gasification medium nozzle being designed to allow the injection of the second gasification medium at a steam / oxygen ratio of 0.5 to 4 kg / m ³ , preferably 0.5 to 3 kg / m ³ . .

According to an advantageous aspect of the fixed-bed pressure gasifier of the present invention, the at least one gasification medium nozzle is designed such that the amount of injected oxygen of the second gasification medium corresponds to 0-50% of the total amount of oxygen supplied.

Advantageously, the fixed-bed pressure gasifier comprises several gasification medium nozzles for the second gasification medium, which are arranged in one or two planes.

According to an advantageous aspect, the fixed-bed pressure gasifier includes at least one inlet (fine fuel inlet) for fine and / or powdered fuel. The differential fuel inlet is designed as a gravity inlet or as a stuffing inlet for fine fuel densified by briquettes.

According to an advantageous aspect of the fixed-bed pressure gasifier, the gasification medium nozzle is a water-cooled gasification medium mixture nozzle (in the case of oxygen and steam as the second gasification medium) or as a water-cooled multipart nozzle (in the case of combined fine fuel feed). Is designed). Preferably, with a free length (free nozzle length) of at least 10 cm, the gasification medium nozzle projects into the gasification space of the fixed-bed pressure gasifier.

According to an advantageous aspect of the present invention, the nozzle orifice of the gasification medium nozzle in one height zone is approximately reproduced in a flat horizontal plane in the height zone, in a vertical stepped arrangement or in the contour of a mushroom-shaped contour or bed surface of a rotating great. Is located in the cone-shaped height zone.

The technical design of the second gasification slagging gasification is simple and robust, and also requires only minor technical adaptations of known and well-tested fixed-bed pressure gasifiers. The same applies to lead-through stubs for gasification medium nozzles and also to feed stubs for fine fuel if desired. The second slagging gasification of the existing equipment of fixed-bed pressure gasification can be increased (with a complete set of gasification medium nozzles) completely (starting with one gasification medium nozzle) to install, retrofit, and operate, or partially It has been found to be particularly advantageous to be able to be operated or to be able to be deactivated or to be adapted to the requirements.

Referring to the accompanying drawings, exemplary embodiments of the present invention will be described in detail.

1 shows a schematic diagram of a fixed-bed pressure gasifier.
2 shows a plan view of section AA.

FIG. 1 shows a fixed-bed pressure gasifier 1, and FIG. 2 shows a cross section of plane A-A in plan view.

At the top of the fixed-bed pressure gasifier 1 is an inlet 2 and a source gas outlet 30 for the assembled solid fuel. At the bottom of the fixed-bed pressure gasifier 1, a rotary grate 5 and a re-discharge 31 for supplying the first gasification medium 6 for non-slag gasification are arranged.

In the upper part of the fixed-bed pressure gasifier, the fuel inlet 2 is open into the hanging axis 28. In addition to the fuel inlet 2 for the prefabricated fuel, an inlet 21 for fine fuel is arranged on top of the fixed-bed pressure gasifier 1. The differential fuel inlet 21 opens into a downpipe 22 held in the suspension shaft 28, which is longer than the suspension shaft 28 and also has a baffle plate ( Ends in the reaction space of the fixed-bed pressure gasifier 1 with 24. The differential fuel inlet may be inactivated with nitrogen 27.

The apparent inner diameter of the fixed-bed pressure gasifier 1 is 4 m and the height of the pile of the fixed bed 3 calculated from the tip 4 of the rotating great 5 is on average 6 m. This is defined by the suspension axis 28 for fuel distribution. The heap of the fixed bed 3 is ideally-typically five layers from bottom to top, namely the first ash zone 14, the first oxidation zone 15, the first gasification zone 16, the first pyrolysis zone. 17, and the first drying zone 18.

At a height of 3 m above the tip 4 of the rotating grate 5, a total of ten stubs 7 for supplying the second gasification medium 8 for slagging gasification are fixed-bed pressure gasifiers 1. Is disposed on the outer jacket 9 of the uniformly distributed.

On the tip 4 of the rotating grate 5, in the upper plane of the first gasification zone 16 and above the first pyrolysis zone 17, a container jacket comprises a supply stub 7.

The supply stub 7 of the upper plane of the first non-slag gasification zone 16 has a gasification medium nozzle 12 that reaches within the gasification zone for the supply of the second gasification medium 8 for slagging gasification. Doing.

In section A-A, the stubs 7 are numbered / 1 / to / 10 / in the clockwise direction. They are guided through the outer pressure-bearing container wall 10 and through the inner steel jacket 11. All six of the ten stubs 7 are provided with a gasification medium nozzle 12. The gasification medium nozzle 12 is designed as a tubular nozzle that is radially aligned and inclined downward at an angle of 15 ° to the horizontal plane. They extend 50 cm into a pile of fixed beds 3. The orifice 13 of the gasification medium nozzle 12 ends in the upper region of the first non-slag gasification zone 16.

The stub 7 directed into the first drying zone 18 is arranged in the briquette press 32 to supply the densified or briquette fine fuel 21.

The fixed-bed pressure gasifier constructed in this way is operated as follows.

In the fixed-bed pressure gasifier 1, about 35% (dry) ash component, about 5% (dry) water component, a remelting point of about 1400 ° C. and a grain size of about 5-100 mm are used. The non-tacky prefabricated hard coal 2 has gasified to a total pressure of about 30 bar. The hard coal 2 is introduced into the fixed-bed pressure gasifier 1 from above. The feed gas 29 leaves the fixed-bed pressure gasifier 1 through the feed gas outlet 30, while the ash 31 is recovered at the bottom by the rotating grates 5. Via the rotary grate 5, the first gasification medium 6 is fed. The amount of first oxygen in the first gasification medium is 12,000 Nm ³ / h (based on pure oxygen), and the steam / oxygen ratio is on average 4.5 kg / Nm ³ .

The amount of the second oxygen of the second gasification medium 8 is all 3200 Nm ³ / h (based on pure oxygen), and the steam / oxygen ratio is 0.8 kg / Nm ³ .

The gasification medium nozzles 12 with the numbers / 3 /, / 4 /, / 8 / and / 9 / are each filled with 600 m _sdt ³ / h of oxygen, and the numbers / 1 / and / 6 / as well. The gasification medium nozzles 12 are each filled with oxygen of 400 m _sdt ³ / h. The second gasification medium is 70 m / s [gasification medium nozzle 12, number / 3 /, / 4 /, / 8 /, / 9 /] and 50 m / s [gasification medium nozzle 12, number / 1 /, / 6 /] flows at a flow rate. In front of the orifice 13, a turbulent zone 19 is formed. In front of adjacent gasification medium nozzles 12, numbers / 8 /, / 9 / as well as numbers / 3 /, / 4 /, two large coherent zones 20 of turbulent zone 19 are formed.

A fine fuel 21 is approximately centered over a consistent area 20 of the turbulent zone 19 of the adjacent gasification medium nozzles 12, numbers / 8 / and / 9 / as well as numbers / 3 /, / 4 /. It is introduced by gravity through the downpipe 22 or through the stuffing inlet by a briquette press 32.

In the lower outlet opening 23 of the downpipe 22, a baffle plate 24 is located, in which a cavity 25 is formed in the heap of the bed 3 fixed below, and the fine fuel 21 therein. ) Can flow freely. The downpipe 22 is supported by a suspension shaft 28 with a holder 26. The vertical distance of the outlet opening 230 to the gasification medium nozzle 12 is 2 m. The downpipe 22 is inactivated with a small amount of nitrogen 27.

The fine fuel 21 comes from the same hard coal 2. The grain size of the fine fuel 21 is 0-2 mm, the ash component is 40% by weight (dry), and the water component is 5% by weight (dry). The two downpipes 22 are supplied with 5.5 t / h of differential fuel 21.

In this example, the heat capacity of the fixed-bed pressure gasifier 1 is increased by about 25% by applying the solution according to the invention. In addition, co-gasification of the fine fuel during the first time is made possible to a considerable extent.

1: fixed-bed pressure gasifier 2: inlet for gasification media
3: fixed bed 4: tip
5: rotating Great 6: first gasification medium
7: stub 8: secondary gasification medium
9: container wall 10: pressure-bearing container wall
11: inner steel jacket 12: gasification medium nozzle
13: Orifice 14 of gasification medium nozzle: first rezone
15: first oxidation zone 16: first gasification zone
17: first pyrolysis zone 18: first drying zone
19: Turbulent Zone 20: Consistent Area
21: Differential Fuel 22: Downpipe
23: outlet opening 24: baffle plate
25: cavity 26: holder
27: nitrogen 28: suspension axis
29: source gas 30: source gas outlet
31: Ash 32: Briquette Press
33: lump aid

Claims (11)

The minimum threshold for the steam / oxygen ratio can be adjusted to a pile of fixed beds above the rotating grate, the feed for the assembled solid fuel, the rotating grate and the fixed bed pressure gasifier on top of the fixed-bed pressure gasifier By means of a fixed-bed pressure gasifier with an adjustable supply for the first gasification medium for non-slag gasification by means of a gas draw having all of its ash outlets at the bottom of the rotary bed In a process for fixed-bed pressure gasification of solid fuels with oxygen- and steam-containing gasification media,
In addition and independently of the first gasification medium supplied by the rotating grate, a second gasification medium for slagging gasification is injected through at least one gasification medium nozzle reaching into the upper region of the fixed-bed pile;
The second gasification medium is injected at a steam / oxygen ratio of 0.5 to 4 kg / m ^{3 and} at a gas discharge rate of 20 to 120 m / s. The method of claim 1,
The fixed-bed pressure gasifier is characterized in that the second gasification medium is injected into the height zone of the fixed-bed pressure gasifier reaching a maximum of 0.5 m below the surface of the bed of the fixed bed from 1 m above the tip of the rotating grate. Process for. The method according to claim 1 or 2,
A process for fixed-bed pressure gasification, wherein a prefabricated solid fuel having a grain size greater than 2 mm is introduced into the fixed-bed pressure gasifier. The method according to claim 1 or 2,
The fine and / or powdered fuel is added to the turbulent zone formed before the gasification medium nozzle, and in any case the amount of added fine and powdered fuel is too large to ensure gasification of the turbulent zone in stoichiometric terms. Process for Bed Pressure Gasification. The method according to claim 1 or 2,
The second gasification medium is alternatively sprayed into two height zones each having a vertical extension of <1 m, which has a minimum vertical distance of 1 m from each other and also the maximum and minimum beds of a fixed bed of a fixed-bed pressure gasifier A process for fixed-bed pressure gasification, characterized in that it is disposed below the pyrolysis zone, respectively, in the upper half of the first gasification zone corresponding to the height. The minimum threshold for the steam / oxygen ratio can be adjusted to a pile of fixed beds above the rotating grate, the feed for the assembled solid fuel, the rotating grate and the fixed bed pressure gasifier on top of the fixed-bed pressure gasifier Raw material gas draw with both ash outlets at the bottom of the chamber, oxygen- and steam-containing, with an adjustable supply for the first gasification medium for non-slag gasification by rotating grate of a fixed-bed pressure gasifier In a fixed-bed pressure gasifier for gasifying a prefabricated solid fuel with a gasification medium,
The fixed-bed pressure gasifier at the level of the upper region of the fixed-bed pile comprises at least one gasification media nozzle projecting into the upper region for the supply of the second gasification medium for slagging gasification,
A fixed-bed pressure gasifier characterized by allowing additional and independent injection of the second gasification medium at a steam / oxygen ratio of 0.5 to 4 kg / m ³ and a gas discharge rate of 20 to 120 m / s. The method of claim 6,
A fixed-bed pressure gasifier comprising a plurality of gasification medium nozzles disposed in one or two planes. The method according to claim 6 or 7,
A fixed-bed pressure gasifier comprising at least one inlet (differential fuel inlet) for fine and / or powdered fuel.





9. The fixed-bed pressure gasifier of claim 8, wherein the differential fuel inlet is designed as a gravity inlet or as a stuffing inlet for fine fuel densified by briquettes. 8. The gasification medium nozzle according to claim 6 or 7, wherein the gasification medium nozzle is a water-cooled gasification medium mixture nozzle (in the case of oxygen and steam as the second gasification medium) or as a water-cooled multipart nozzle (in the case of a combined supply of fine fuel). Fixed-bed pressure gasifier, characterized in that designed. 8. The fixed-bed pressure gasifier of claim 6 or 7, wherein with a free length (free nozzle length) of at least 10 cm, the gasification medium nozzle protrudes into the gasification space of the fixed-bed pressure gasifier. .

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