EP0194252B1 - Installation for gasifying fuels - Google Patents

Abstract

1. Arrangement for gasifying fuels with oxygen or oxygen-containing gases and steam, with a shaft-like vessel (8) to accommodate solid charging stock (31), a gas discharge duct (33) provided on the upper end of the vessel (8), and a primary gas chamber (4) in connection with the shaft-like vessel (8) on the lower end thereof via a passage (34), a burner (23) provided in the primary gas chamber and including feed means (24, 25, 26) for oxygen or oxygen-containing gases as well as for fuels and optionally steam, with a trough (19) to accommodate slag (22), and a support bottom (17) provided between the trough (19) and the shaft-like vessel (8) and projecting into the primary gas chamber (4) so as to form a sloping bed of solid charging stock (31) having a sloping surface (37) facing the burner (23), characterised in that the primary gas chamber (4), adjacent the passage (34), is provided with a charging opening (35) for top-charging charging stock (32) to be gasified, the supporting bottom (17), on the side of the burner, being extended so far as to form a second sloping bed of charging stock (32) to be gasified having a second, free sloping surface (38) facing the burner (23) and lying in front of the first sloping surface (37).

Description

The invention relates to a device for the gasification of fuels with oxygen or oxygen-containing gases and water vapor with a shaft-shaped container for receiving a solid charge, a gas discharge line at the upper end of the container and a primary gas chamber connected to the shaft-shaped container at its lower end via a passage , in which a burner is provided, which has feeds for oxygen or oxygen-containing gases and for fuels and possibly water vapor, with a trough for receiving slag and with a support base provided between the trough and the shaft-shaped container and projecting into the primary gas chamber to form a with a bed surface facing the burner bulk bed of the solid cargo.

A device of this type is known from DE-A 2 920 922. With this device, it is possible to use and gasify fuels containing free carbon, such as anthracite, bituminous coals, lignite, briquettes etc., as charge material, the fuels in the primary gas chamber having a cone of free surface which is in a slag bath based, form.

The gasification of inferior fuels can lead to undesirable emissions that are contained in the withdrawn product gas. For example, it is disadvantageous when gasifying highly volatile hard coal with a high tar content, since the tar is contained in the product gas. When gasifying wet brown coal, the product gas contains a large amount of water vapor.

The object of the invention is to further develop a device of the type described in the introduction such that not only the gasification of high-quality fuel, for example coke, but also inferior fuel, for example wet brown coal or hard coal with a high tar content, used tires, etc., is possible, however, the product gas is free from disturbing, in particular reducing the calorific value and restricting further use and polluting the environment.

This object is achieved in that the primary gas chamber has, in addition to the passage, a charging opening for a charge to be gasified to be introduced from above, the support base being extended so far on the burner side that there is a burner in front of the first bed surface with a free second bed surface forms facing second bulk bed of the batch to be gasified.

The further batch to be gasified, which forms the free bed surface directly exposed to the burner's fuel jet, is gasified by the primary gas as a result of the flow through the bed of bulk material formed by it, whereby a raw gas is formed, which is forced to be connected to the first bed surface behind the batch to be gasified to flow through lying solid cargo, whereby it is filtered. Any tar contained in the gas coming from the primary gasification chamber immediately after its formation is still cracked in the hot zone of the shaft-shaped container, as a result of which a tar-free product gas can be withdrawn from the container.

A compact and thermally favorable design permitting embodiment is characterized in that the shaft-shaped container is divided by a partition projecting into the container from above into two successive compartments in the direction of the burner, the compartment facing away from the burner having the gas discharge line and for receiving the first Bulk material bed, in particular a coke bed, is determined and the burner-side section is intended for receiving the second bulk material bed of the charging material to be gasified, in particular a waste material or waste fuel, and the cone of the second bulk material bed starts from the lower edge of the partition.

Advantageously, a feed line for the charge to be gasified opens into the burner-side wall of the container, which is delimited on the wall side by a segment-shaped sliding surface, a partition wall for forming two sections of the container starting from the burner-side wall and being inclined, preferably at an angle of inclination between 30 and 45 _° , extends downwards.

The partition is expediently provided with internal cooling and lined with a refractory material at least in the lower part.

A fuel-saving method for operating the device according to the invention is characterized in that a stoichiometric ratio of C to 0 in the burner is set in the range from 1.0 to 2.0, the furnace temperature being in the range from 1500 to 1800 _° C.

The invention is described in more detail below with reference to two embodiments and an application example, FIGS. 1 and 2 each representing an embodiment in vertical section through a shaft carburetor.

The shaft carburetor 1 has a vertical upper section 2, preferably having a circular cross section, and a laterally angled lower section 3, which forms the primary gas chamber 4. Since the shaft carburetor 1 can be used without pressure or under pressure, its outer jacket 5 is designed accordingly, that is to say as a pressure vessel or as an ordinary gas-tight vessel.

Provided within the outer jacket 5 is a container 8 having cooled walls 6, in particular having walls 6 composed of tubes 7 through which coolant flows and which is designed as a basket. The part of the basket 8 located within the vertical section 2 of the shaft gasifier 1 has one to form two departments 9, 10 from the upper end 11 of the basket 8 Cooled partition 12 to be extended at the bottom, the lower free edge 13 of which lies approximately at the level of the connection 14 of the angled lower section 3 of the shaft gasifier at its vertical part 2. At this height, the basket also has an inwardly projecting projection 15, which forms the upper boundary of the primary gas chamber 4 underneath.

The lower end 16 of the basket 8 is formed by an approximately horizontally directed support base 17, which also has internal cooling and whose free end, which projects into the primary gas chamber, is designed as a slag overflow weir 18. Beneath the support base 17 there is a trough 19 which is filled with coolant 20 for granulating the slag 22 which passes over the overflow weir and exits the primary gas chamber 4 through a passage opening 21.

Above the slag overflow weir 18, a burner 23 opens into the primary gas chamber 4, into which feeds 24, 25, 26 for fuels, oxygen (or air) and optionally water vapor open.

The basket 8 is coated on the inside up to the height of the first third of its vertical part - its partition 12 on both sides - with refractory material 27. The two sections 9, 10 of the basket 8 each have at their upper end closable feed openings 29, 30 for the goods 31, 32 to be charged, by means of a lock 28. The section 9 located further away from the burner 23 is provided near the upper end 11 with a gas discharge line 33 for the product gas formed and opens into the primary gas chamber 4 by means of a passage 34. The section 10 located closer to the burner 23 opens into the primary gas chamber 4 with one Passage 34 adjacent charging opening 35th

• Zunächst wird in die vom Brenner 23 entfernter liegende Abteilung 9 Chargiergut 31, insbesondere Koks, eingefüllt, wodurch sich entsprechend dem Schüttwinkel 36 des Kokses ein Schüttgutbett mit einer dem Brenner 23 zugewandten ersten Schüttungsfläche 37 bildet. Diese Schüttungsfläche 37 geht von der unteren Kante 13 der Trennwand 12 aus.

The function of the device is as follows:

• First of all, charging material 31, in particular coke, is poured into the compartment 9 located further away from the burner 23, whereby a bed of bulk goods with a first bed surface 37 facing the burner 23 is formed in accordance with the angle of repose 36 of the coke. This bed surface 37 starts from the lower edge 13 of the partition 12.

Charge material 32 to be gasified is then introduced into the section 10 of the basket 8 closer to the burner 23, which charge material 32 forms a further bed of bulk goods, which covers the first bed of bulk goods and has a free bed surface 38 facing the burner, against which the burner jet 39 is directed .

The charge material 32 to be gasified which is introduced into the section 10 closer to the burner 23 can be of inferior quality, for example lignite, highly volatile hard coal or used tires. This charge is gasified after the burner 23 is ignited, the water vapor contained in the charge taking part in the gasification reactions and higher hydrocarbons being cracked from the pyrolysis and the resulting raw gas being forced as a result of the arrangement of the gas discharge line 33 in the section 9 lying away from the burner to pass through the bulk bed of coke 31 behind it. When passing through the coke, the raw gas is filtered so that the raw gas leaving the department 9 has a high purity; above all, it is free of higher hydrocarbons.

It depends on the thickness 40 of the bulk material bed of the charge material 32 to be gasified and on the setting of the primary gasification whether the charge material lying behind the second bulk material bed, e.g. the coke, also gasified or used only or primarily as a filter for the raw gas passing through. The primary gasification is set either via the ratio of oxygen to carbon carrier in the burner, or via the total amount of primary gasification substances, or - if pure oxygen is introduced via the burner instead of air - via the ratio of oxygen to water vapor. Depending on the position of the lower edge 13 of the partition wall 12, the thickness 40 of the second bed of bulk material of the charging material 32 to be gasified and thus gasification of the charging material 31 lying behind it is influenced.

According to the embodiment shown in FIG. 2, a feed line 41 for the charge material 32 to be gasified opens into the vertical part 2 of the shaft gasifier 1, said feed line 41 coming from a container 42 connected to this feed line 41 by means of a conveying device, such as a screw conveyor 43, for forming a bulk material bed the primary gas chamber 4 flows. According to the embodiment shown in FIG. 2, the partition 12 ′ is directed obliquely downwards, preferably from the burner-side wall 44 of the basket 8, preferably at an angle of 30 to 45 ° to the primary gas chamber 4, in order to form the two bulk beds.

The cargo to be gasified 32 slides through the feed line 41 via a sliding surface 45, which is cooled and provided with a refractory lining, up to the charging opening opening into the primary gas chamber 4.

• Dem Brenner 23 wird als Brennstoff Altöl sowie ein pastöser Rückstand aus einer Papierfabrik (u.zw. ein Hydrolyse-Rückstand aus einer enzymatischen Hydrolyse) und Luft unter einem Druck von 4 bar zugeführt und verbrannt. In Tabelle I ist die Analyse des Altöls, in Tabelle II die Analyse des pastösen Rückstandes angegeben.
  

The gasification of low-quality fuel is explained below using an example:

• Waste oil and a pasty residue from a paper mill (including a hydrolysis residue from an enzymatic hydrolysis) and air are fed to the burner 23 as fuel and burned under a pressure of 4 bar. In Table I the analysis of the waste oil is given, in Table II the analysis of the pasty residue.
  

Sewage sludge, paper mache or dust-like fuel can also be fed to the burner 23 in pasty form.

Waste oil in an amount of 3800 kg, pasty residue in an amount of 1258 kg and air preheated to 500 _° C in the amount of 32,000 Nm ^{3 were} fed in per hour.

The primary gas generated by combustion in the burner was 38,181 Nm ³ / h (moist) at a temperature of 1510 _° C. Upon contact with the batch 32 to be gasified in the second bulk bed, the primary gas reacts with the batch 32 to be gasified, which consists of waste tires (analysis in Table 111) and deinking sludge - a residue from waste paper processing with printing ink and fillers (chemical analysis in Table IV) Raw gas.

Used tires were used in an amount of 1300 kg / h and deinking sludge in an amount of 2560 kg / h. The raw gas was 864 _° C when it entered the second bulk bed. The raw gas then flowed through the bulk bed of coke and was withdrawn as a finished product gas in an amount of 46,924 Nm ³ / h. Its analysis is shown in Table V.

The thermal efficiency in the process, which is defined as the ratio of the product gas quantity times the product gas calorific value increased by the sensible heat of the product gas to the sum of the amount of the input materials times their respective calorific value, was 91%. The gasification efficiency, which is defined as the ratio of the amount of product gas multiplied by the product gas calorific value to the sum of the amount of the feed materials times their respective calorific value, was 73%.

The calorific value of the product gas was 949 kcal / Nm3. In the slag container 19, glassy solidified granulated slag was obtained in an amount of 1408 kg / h.

According to a further example, the device was operated at a pressure of 4 bar. Waste oil was fed to the burner in an amount of 1800 kg / h and preferably air preheated to a temperature between 100 and 500 _° C. in an amount of 27906 Nm ³ / h. So-called BRAM (fuel from waste) was used in a quantity of 13147 kg / h as the batch to be gasified. The consumption of coke as a charging material was 399 kg / h. The resulting raw gas was produced in an amount of 45500 Nm3 / h.

The burner was operated with a ratio of C to O = lambda of the order of 1.5, the temperature in the primary gas chamber being 1656 _° C. and the temperature of the raw gas 849 ° C. Tables VI to IX below show the analytical values for the waste oil, the BRAM, the product gas and the coke.

Claims (5)

1. Arrangement for gasifying fuels with oxygen or oxygen-containing gases and steam, with a shaft-like vessel (8) to accommodate solid charging stock (31), a gas discharge duct (33) provided on the upper end of the vessel (8), and a primary gas chamber (4) in connection with the shaft-like vessel (8) on the lower end thereof via a passage (34), a burner (23) provided in the primary gas chamber and including feed means (24, 25, 26) for oxygen or oxygen-containing gases as well as for fuels and optionally steam, with a trough (19) to accommodate slag (22), and a support bottom (17) provided between the trough (19) and the shaft-like vessel (8) and projecting into the primary gas chamber (4) so as to form a sloping bed of solid charging stock (31) having a sloping surface (37) facing the burner (23), characterised in that the primary gas chamber (4), adjacent the passage (34), is provided with a charging opening (35) for top- charging charging stock (32) to be gasified, the supporting bottom (17), on the side of the burner, being extended so far as to form a second sloping bed of charging stock (32) to be gasified having a second, free sloping surface (38) facing the burner (23) and lying in front of the first sloping surface (37).

2. Arrangement according to claim 1, characterised in that the shaft-like vessel (8), by means of a partition wall (12) extending from above into the vessel (8), is divided into two compartments (9, 10) lying behind each other in the direction to the burner (23), the compartment (9) facing away from the burner (23) being provided with the gas discharge duct (33) and being destined to accommodate the first sloping bed of charging stock, in particular a coke bed, and the burner-side compartment (10) being destined to accommodate the second sloping bed of the charging stock (32) to be gasified, in particular a used substance or waste fuel, and the sloping surface of the second sloping bed departing from the lower edge (13) of the partition wall (12) (Fig. 1).

3. Arrangement according to claim 1 or 2, characterised in that a supply duct (41) for the charging stock (32) to be gasified enters into the burner-side wall (44) of the vessel (8), a segment-shaped slide surface (45) delimiting the supply duct on the side of said wall, a partition wall (12') for the formation of two compartments (9, 10) of the vessel (8) departing from the burner-side wall (44) and extending obliquely downwards, preferably at an angle of inclination of between 30 and 45_° (Fig. 2).

4. Arrangement according to one of claims 2 or 3, characterised in that the partition wall (12, 12') is provided with an internal cooling and at least in its lower part is lined with refractory material (27).

5. Method of operating an arrangement according to one or more of claims 1 to 4, characterised in that a stoichiometric ratio of carbon to oxygen in the range of 1.0 to 2.0 is adjusted at the burner, the firing space temperature lying in the range of from 1,500 to 1,800 _°C.

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