NO822797L - METHOD AND APPARATUS FOR MANUFACTURING SYNTHESIC GAS - Google Patents

Description

The autothermal gasification of carbon-rich materials, especially coke and coal, with technically pure oxygen or mixtures of oxygen and additive gases, preferably water vapor, nitrogen or carbon dioxide, is known. The gasification is then carried out in a suitable reactor room, which can have different designs, so that the gasification can take place according to the type, e.g. of fly stream gasification or fixed storage gasification at normal pressure or elevated pressure. Until now, aggregates used for carbon-rich materials must predominantly have a favorable effect on the slag's physical properties.

Thus, German patent 1 068 4-15 describes a method for the production of synthesis or combustion gas with gasification of solid fuels with oxygen, at temperatures from 1200 to 1375°C, as a flux can be added to reduce the slag-melting temperature, e.g. e.g.

lime. In the "method according to DAS 1 508 083 for the production of reducing gases for iron production by gasification of solid, carbon-containing fuels with air in a fluidized bed at 1000 to 1500UC, one adds to the fuel:: limestone','~ lime or silicic acid and clay soil -containing materials in such quantities that they increase the ash melting point above the working temperature. In DE-AS 25 20 584, the gasification of sulphurous coal in an iron bath reactor is described, whereby lime, limestone or dolomite is added to the iron bath to produce a slag that has a desulfurizing effect DE-PS 930 539 and 1 012 4.20 mentions a method for gas generation where steam at 775 - 980°C is introduced into a mixture of carbonaceous, solid fuel and calcium oxide or lime,

in that the amount of calcium oxide or lime present in the ion zone is sufficient to approximately convert the co-formed carbon dioxide into carbonate.

In the method according to US patent 3 01 7 259, coke and lime are dispersed in water vapour, and reacted with oxygen in a fluidized bed reactor at 1650 - 2750°C, calcium carbide and synthesis gas (CO + H^) being formed. The reaction product is cooled with hydrocarbon oil to below 4-25°C,

as it separates a suspension of calcium carbide from the synthesis gas.

In the method according to the invention, selected additives are used which at least find some components of the ash or slag resulting from the mineral in the coal by chemical reaction, whereby in a secondary reaction, chemically-technically usable products are produced, so-called valuable substances. Thereby, the additives are preheated by the hot synthesis gas to the required temperature,

and the energy requirement of the endothermic secondary reaction is completely covered by part of the energy released by the autothermal gasification. The secondary product is removed melted from the reactor space.

As is well known, especially the fossil, solid carbon carriers such as hard and lignite or their coke are often equipped with a very different content of ballast material. The ballast material mainly consists of a majority of minerals which are partly present in a good mixture with the carbon and of which the glow residue forms the ash More than 35 elements can be detected in the ash, which is why there is interest in extracting raw materials from the ash. So far, however, no similar methods have succeeded. The reason for this is above all the usually very low content of the ash in valuable steel products. metals which, in turn, have been at the forefront of interest until now. The main minerals thus remain largely uninterested. Although fly ash and granulated ash can be used in the construction industry, which already today in power plants forms slag and ash quantities such as coal can only be added up to about 15% and in the case of lignite only up to around 8% to a utilization major problems. These will become. stronger when they in the future one is put into operation in large-scale coal gasification plants, as on the one hand the high degree of enrichment of heavy metals and radionuclides excludes certain application areas of the ash or the slag that was previously proposed, on the other hand, the utilization capacity is exhausted, and the ash and slag intake is further increased by the coal gasification.

In the case of known coal gasification plants it prevails

instead of ash and slag formation, usually very high temperatures. At the same time, ash or slag usually melted. The minerals in the coals are mainly illite and kalinite as clay minerals, sericide as mica minerals, pyrite, marcasite, limonite, hematite and iron spar as iron minerals, lignite, ankerite, calc spar and dolomite as carbon spar, apatite as phosphorus mineral and quartz, in addition a number of further, but rarer detectable oxides, hydroxides and sulphides as well as certain salts, show different conditions depending on the heating rate and atmosphere. In general, adsorbed water is expelled first by heating, then crystal water, water from the 8H group and carbon dioxide from carbonates. At temperatures above 1500°C, there is a clear transport of some oxides over the gas phase with the formation of gas complexes monoxides or sulphides, which after back-reaction lead to aero solar formation. In particular, this takes place with silicon dioxide, aluminum oxide and iron oxide. Moreover, at the high heating rates, minerals break down strongly into amorphous oxides, which are carried along by the synthesis gas flow.

A large part of the silicon dioxide melts and later forms a gaseous mass. Under strongly reduced conditions, above all in the presence of carbon, reduction of the metal oxides to metals can also be observed. The appearance of iron is preferred, but also the formation of calcium carbide which is also formed intermediately above a metallic step or the appearance of ferrosilicon is observed.

In the method according to the invention, these properties of the mineral components of the carbon-rich materials, especially coal, are combined and utilized on

favorable way.

Thereby becomes

1. Large parts of the slag and ash chemically transformed and transferred to chemical-technical products, 2. Certain components, e.g. Al^O^enriches in a dust fraction which gives this good hydraulic binder property, 3. The gasification heat generated at a particularly high temperature level is used directly for high temperature reactions, k> The carbon dioxide in the synthesis gas is kept to a minimum, and 5. Large parts of the otherwise from flying dust exiting the reactor is retained in the reactor and converted by chemical reaction. This is achieved by the hot synthesis gas being fed directly into a storage of an aggregate mixture immediately after its formation. The aggregate mixture contains a reaction agent, especially carbon in the form of coke, sulfur coke, anthracite, charcoal or peat coke for slag reduction. Thereby, the partially liquid slag and fly ash particles are separated for a large part on the storage layer's surface and then form a surface film. Here, due to the high temperatures, a reaction occurs and a reduction zone forms. During consumption of the aggregate mixture, the desired secondary product is formed. This can e.g. be ferrosilicon or calcium carbide. The dimensioning of the specific amounts of aggregate referred to the amount of carbon-rich material used can be varied within wide limits. Sensibly, the amount of key components in the ash to be converted above the stoichiometry of the amoformation reaction gives the lower limit of the amount of aggregates f is, (cf. ex. 1:), while the amount of heat released by the autothermal gasification reaction over the energy consumption of the conversion reaction forms the upper limit of the amount of aggregates (cf. ex. 2). In detail, the invention now relates to a method for the production of synthesis gas, (CO + Hg) by autothermal gasification of finely divided carbon-rich materials with oxygen, possibly in the presence of additive gases. The method is characterized by carbon dust with a particle size of 0 - 0, 1 mm together with oxygen and possibly an additive gas is injected into a 2000 to 2600°C gasification zone of the formed fly ash-containing raw synthesis gas by the inherent thermal energy is passed through a reduction zone filled with the starting materials for an endothermic carbothermic reduction and formed by the carbothermic reduction formed synthesis gas through an associated preheating zone filled with the same substances and is removed at a temperature of 300 - 1500°C for purification and conversion, and that during the reduction zone the reduction product from the carbothermic reduction is removed as well as forming a slag molten from a collective and afterreaks jonzone The method according to the invention can further preferably and optionally characterized by a) The ash part of the injected carbon dust, as well as the coal used for the carbothermic reduction, is at least partially used as a reaction participant in the carbothermic reduction, b) a raw synthesis gas that leaves the preheating zone is freed of dust and ash, and these solids is at least partially injected into the cycle together with new carbon dust again above the forgassing zone into the reduction zone, c) Starting materials for the carbothermic reduction

. a grain size of 10 to 20 mm is used, or of 20 -

4-0 mm,

d) The reduction zone consists laterally in an open connection with at least two gasification zones and upwards with the preheating zone. e) Preheating reduction and the reduction zone are coated with coke, iron waste and possibly quartz, with ferrosilicon extracted as a reaction product from the carbothermic reduction at 1300 to 1800°C, f) the preheating zone and the reduction zone are coated with coke or calcined anthracite and lime, with the reaction product calcium carbide is extracted from the carbothermic reduction at 1800 to 2300°C, g) the preheating zone and the reduction zone are coated with coke, calcium phosphate and quartz, as elemental phosphorus is extracted as a reaction product of the carbothermic reduction at 1300 to 170o°C, h) the preheating zone of the reduction zone is coated with coke and oxidic iron ore, as metallic iron is extracted as a reaction product of the carbothermic reduction at 13 00 to 1800°0,

i) that the additive gas used is CO, COg, Ng» water vapor or synthetic gas fed into the circuit,

j) in the gasification zone, work is done" with a stoichiometric excess of oxygen in relation to the oxidation to CO,

k) a component of the starting materials is dosed for the carbothermic reduction targeted along the inner wall of the preheating zone and reduction zone one.

Furthermore, the invention also includes a device (cf. Fig. 1) for carrying out the process, as the device is characterized as a wood shaft furnace 6 which, from top to bottom, consists of an elongated preheating chamber 6c,

a reduction chamber 6b, and post-reaction chamber 6d, which open into each other, laterally to the reduction chamber 6b adjacent to and with this openly connected cylindrical gasification chamber 6a, into which each runs one nozzle 3 for the common supply of carbon dust, oxygen and possibly additive gases, a supply 8 for the starting materials

of the carbothermic reduction, and an exhaust line 9,

12 for raw synthesis gas at the top of the shaft furnace 6, at least one exhaust line 7a, 7b, on post-reaction chamber 6d for removal of molten slag and molten reaction product from the carbothermic reduction. The device according to the invention can also preferably, by choice, be characterized by) each time one of each of the nozzles 3 pre-connected intermediate bunker 3 for carbon dust a dedusting device 11 1 extraction line 9, 12 for raw synthesis gas and return lines 13 for the secreted mineral dust from the dedusting device 11 to the individual intermediate bunkers 2,

b) in the upper part of the shaft furnace 6 vertically and circularly arranged dividers 16 to delimit the

annulus 6e between the separators 16 and the inner wall of the shaft furnace "6, as well as at least two transport lines 15 for the supply of a component of the starting materials for the carbothermic reduction through the annulus 6e while forming an annular storage mantle (cf. fig. 2) which protects the inner wall of the shaft furnace 6.

The method according to the invention can be carried out in a variety of ways. With reference to figures 1 and 2 of the drawing, the methods and device according to the invention will be explained in more detail, as carbon-rich materials intended for gasification (carbon dust) are briefly referred to below as gasification coal.

Fig. 1

Finely ground and pre-dried gasification coal (particle size: 90% ^ um) is fed over supply 1 and intermediate bunker 2 to each time a dust gasification burner 3, where they are injected with oxygen from line k and possibly additive gas, especially carbon dioxide, water vapour, carbon monoxide and crude synthesis gas from line 5 into the gasification zone 6a of the reactor chamber (shaft furnace) 6 according to the invention and is autothermally gasified. Thereby, within the framework of the invention, oxygen and/or additive gas can be used as a carrier gas for gasification coal. The reactor chamber (shaft furnace) 6 is according to the invention designed so that directly to the gasification zone 6a towards the axis cleans a reduction zone 6b which consists of a loose layer of each time aggregate mixture. Thereby, the concentration of aggregates and this mixture is preferably 10 - 20 mm or 20 - 4-0 mm. Above the layer, a preheating zone 6c is arranged, which likewise contains a loose layer of aggregate mixture so that the effect of gravity on the aggregate the downward trend corresponds to consumption in the reduction zone 6b. Below the reduction zone 6b, a collection and post-reaction zone 6d is arranged, into which the molten slag and reduction product drips from the reduction zone 6b. The collection and after-reaction zone 6d is equipped with at least one closable tap-off opening so

is led that molten slag and molten reduction product can be removed over the 1-ednings-7a and/or 7b. It is then granulated or cooled in vats.

While in the gasification zone 6a the temperature is set using additive gases of approx. 2000 - 2600UC, fr em-comes in the reduction zone 6b a temperature of 1300 - 2300°C. The aggregate mixture contains a reducing agent, preferably coke, degassing coke, anthracite, charcoal or peat coke, and for the desired reaction<y>specific additional materials. Important constituents allow the reducing agents only insofar as their degassing or reaction products (hydrocarbons, tar) do not interfere with further processing of the produced synthesis gas. Optionally, such reducing agents can be calcined in advance. The gasification products formed in the gasification zone 6a are forced through the reduction zone 6b and the preheating zone 6c, where they

provides an inherent heat until the aggregate mixture itself emerges at the top of the reaction chamber with temperatures between 350 and 1500°C. All according to the requirement for the quantity produced

reduction product and/or the desired exit temperature of the raw gas, the amount of aggregate can be dosed accordingly according to quantity and composition. Minimum raw synthesis gas temperatures occur when the preheating zone is

shaped so that a storage surface available for heat exchange becomes very large and the energy consumption by the reduction reaction corresponds to: the energy release by means of the autothermal gasification reaction. At the upper part of the reaction space, there is a suitable device for introducing the above 8 added aggregate mixture, preferably in the form of slides, which are sealed against gas,

or gout stopper. In line 9, at high exit temperatures of the room synthesis gas, a de-heating vessel 10 can be arranged, so that the raw synthesis gas is dedusted in a heat deduster 11, and can be led away via line 12. The dust removed from the hot-removal exercise 11 can either over wire 13

and intermediate bunker 2 is again fed back into the gasification bed 6a and reduction ion zone 6b, or is withdrawn via line 14-, or certain quantities are simultaneously fed via 13 and 14-. In this way, one can either remove all residual ash and ballast substances from inserted used materials such as slag, over the lines 7a or 7b or parts thereof as dust from 11 above the line

U.

Fig. 2.

In a further design of the method according to the invention, in contrast to fig. 1 only be prescribed to introduce a component of the aggregate mixture via line 15, separated by a remaining aggregate mixture into the reactor space and an auxiliary build-in 16 and achieve a column or cylinder jacket-like distribution of the component in the storage.

The gasification zone can be coated with excess oxygen, which results in high gas temperatures. In addition, the outer storage jacket 6c takes over a protective function for the inner wall of the reactor chamber.

In the ■• following examples vol u md el ene refers to the normal state at 270 K and 1.013 bar.

Example 1

Synthesis gas is required to produce around 52.5 tonnes per hour methanol. For this, around 121,000 m^/hour of CO + Hg must be produced. which is to take place by the conversion according to the invention of silicon dioxide from the ash to ferrosilicon 4-5% Si by autothermic, gasification dried finely ground (diameter = 90 $^90um) unwashed, raw fine coal with the addition of pre-dried blast furnace coke.4- ( diameter 10 - 20 mm ) and iron waste (95% Fe). Thereby, corresponding fig. 1 over line 1 under 6o tons/hour of fine coal dust (diameter 90 $^90 um) into bunker 2 and is gasified from there in dust gasification burners 3 together with around 39,290 m per hour 99.9 $-ig oxygen from line 4-. Above line 8, the shaft furnace 6 has been equipped with a storage of a mixture (diameter = 10 -20 mm) of coke (for reduction of SiOj-,) and crushed iron waste as it per hour is consumed approx. 4-, 17 tonnes (2.08 tonnes per hour of coke and 2.09 tonnes per hour of iron waste). While in the gasification zone 6a, during the addition of around 5,000 m of carbon dioxide from line 5, which forms a settling gas at temperatures of around 2,000 - 2,300°C, synthesis gas enters the reduction zone 6b, slag reduction. Thereby, both SiOg and FegO-^ are reduced and ferrosilicon is formed at around 1600°C. This emerges molten, and drips through the storage into collection and post-reaction zone 6d, from which 4-.2 tonnes of ferrosilicon 4-5% Si over 7a or resp. 7b. The synthesis gas is then fed into the aggregate mixture and preheated in a preheating furnace 6c to approx. 1500°C. Thereby, part of the produced fly ash is retained by the storage, and fed back to reduction zone 6b. The synthesis gas escapes over line 9, heating vessel 10 and the heat-removing dust 11-. Around 122,100 m<3> will be removed above line 12

per hour pre-dusted raw synthesis gas (around 121,000 m 3 per hour CO + Hg) by composition: around 76 - 77 vol$ CO and around 22 vol% H2 and around 1 - 2 vol% Ng, COg. The dust separated in 11 returns^partially over 13. The part of dust extracted over 14 contains around 57 wt% of AlgO-^ next to mainly CaO and MgO. Above the return dust amount, the amount of it from 6b over 7a or 7b removed slag is applied. Thus, a total of around 4.2 tonnes per hour dust and slag.

In the case of a normal jet stream gasification, the amount of dust and slag would amount to around 7.9 tonnes per hour. slag-

and ash removal can thus be reduced by around 4-2%' in relation to the state of the art with the method according to the invention. At the same time, by increasing the AlgO^ part in the flying dust fraction (line 14-), a hydraulic product usable as a binder is produced, as well as ferrosilicon 4-5 Si which is the desired valuable reduction product.

Example 2.

Ferrosilicon production is a high-temperature process that was previously carried out in electrothermal furnaces. The method according to the invention can also be expanded so that the amount of aggregate is expanded with quartzite, and thus the amount of ferro salicium is increased. In this way, the predominant part of gasification heat can be extracted, in the form of a chemically bound energy.

A gas generator which, by the method according to the invention, provides raw synthesis gas for the operation of a 1000 tato methanol plant, produces per hour around 95,800 m 3 CO + H . Thereby, the corresponding fig. 1 over line 1 and bunker 2 4-6.73 tonnes per hour unwashed pre-dried and finely ground (diameter = 90% ^ 90 ym) raw fine coal for dust gasification burners 3, and autothermally gasified with about 32,560 m of oxygen, 99»9%, however, without additive gas at 2200°C to 2600°C. Above line 18, shaft furnace 6 is coated with an aggregate mixture (diameter = 10 - 20 mm) consisting of around 5.15 tonnes per hour blast furnace coke 4- (pre-dried) around 7.4-1 tonnes per hour broken quartzite (95%- i. g) and around 0.67 tonnes per hour iron waste

(piece-shaped approx. 95% Fe).

In reduction zone 6 b, conditions such as

in example 1. Here around 5.89 tonnes are formed per hour ferrosilicon, 75% of the Si that has melted flows into the collection and post-reaction zone 6d, and is removed there from above line 7a resp. 7b. The synthesis gas and the CO released during the reduction flow in 6c through the aggregate mixture storage and thereby cool to around 350 - 4-50°C. Then removed. over line 9, dedusting 11 and line 12 around 97,050 m3

per hour pre-dusted raw synthesis gas (around 95,800 m o per hour CO + Hg) with composition: Around 77 vol# CO, around 21 vol$ Hg, and around 2 vol% Ng, COg. The flying dust, which in example 1 is again enriched with AlgO, can be fed back over 13 and 2 in variable quantities to the dust gasification burners 3 and 2, respectively. taken over 14-. Together, around 3.4-9 tonnes appear per year. hour dust and slag.

This is compared to the normal jet gasification, only around 52% of the normal dust and slag extraction. In addition, according to the invention, around 5.89 tonnes per hour ferrosilicon, 75% Si which desired valuable reduction products.

Example 3

Because without ferrosilicon, the calcium carbide otherwise produced in electrothermal furnaces can also be produced as a reduction product in a coal gasification according to the method according to the invention.

American fibrous coal is used as gasification coal, which in its raw state contains approx. 11.5% by weight of ash and 2.8% by weight of water. The combustible part of this fibrous coal contains 85.55 wt% C, 5.23 wt% H, 6.24 wt% 0, 1.52 wt% N, 1.4-6 wt% S. The calcium oxide content of the ash is

approx. 50% by weight, quite high. Calcined anthracite serves as a reducing agent.

Analogously to previous examples, 106.91 tonnes per hour raw dried to 90% less than 90 ura finely ground coal dust, gasifies at 2200°-2600°C with around 70,720 m 3 per tilne oxygen, 99.9%-lg then it is possible in the reduction sonent6b by the method according to the invention

of aggregate f the mixture consisting of around 4-8.4-5 tonnes per hour of quicklime, 96% lg and around 36.06 tonnes per hour calcined anthracite at approx. 2000°C, around 60 tonnes are melted per hour 80%-lg calcium carbide, since over 14- around 10.82 tonnes are removed per hour of dust. At the same time, around 231,000 m 3 occur per hour pre-dusted raw synthesis gas which leaves the shaft furnace 6 at around 4-00°C and contains approx. 73 - 74- vol# 00, 24- - 25 vol/o Hg, and around 1 - 3 vol$ Ng, COg. Particularly advantageous is the high content of basic aggregates in the mixture, so that the raw synthesis gas is practically sulphur-free.

Claims (15)

1. Process for the production of synthesis gas (CO + Hg) by autothermal gasification of finely divided carbon-rich materials with oxygen, possibly in the presence of additive gases, characterized in that the coal dust is injected with a particle size of 0 - 0.1 mm together with oxygen and possibly an additive gas in a gasification zone held at 2000 - 2600°C that the formed fly ash-containing raw synthesis gas with inherent thermal energy is passed through a reduction zone filled with the starting materials for an endothermic carbothermic reduction and multiplied by it by the carbothermic reduction ?form ede synthesis gas through a preheating zone connected to it filled with the same substances and removed at a temperature of 300 - 1,500°C for purification and conversion, and that during the reduction zone the reaction product of carbothermic reduction, as well as formed slag, melted and ef lyt end from a collection and after-reaction zone. 2. Method according to claim 1, characterized in that the ash part of the injected coal dust and the coal used for the carbothermic reduction are at least partially used as reaction participants in the carbothermic reduction. 3. Method according to claim 1 or 2, characterized in that a raw synthesis gas that leaves the preheating zone is freed of dust and ash, and these solids are at least partially injected in a circuit together with fresh coal dust again over the pregassing sGrø into the reduction zone. 4-. Method according to one of the claims 1-3, characterized in that starting materials: for the carbothermic reduction are used in a grain size of <1> 0 - 20 mm, or 20 - 4.0 mm. 5. Small progress according to one of claims 1-4, characterized in that the reduction zone is laterally in open connection with at least two gasification zones upwards in the preheating zone. 6.. - ■ Method according to one of claims 1-5, characterized in that the preheating zone and the reduction zone are coated with coke, iron waste and possibly quartz, ferrosilicon being extracted as a reaction product of the carbothermic reduction at 1300 to 1800°C. 7. Method according to one of claims 1-5, characterized in that the preheating zone and the reduction zone are coated with coke or calcined anthracite and lime, calcium carbide being recovered as a reaction product of the carbothermic reduction at 1800 to 2300°C. 8. Method according to one of claims 1-5, characterized in that the preheating zone and the reduction zone are coated with coke, calcium phosphate and quartz, elemental phosphorus being extracted as a reaction product of the carbothermic reduction at 1300 to 170o°C. 9. Method according to one of claims 1-5, characterized in that the preheating zone and the reduction zone are coated with coke and oxidic iron ore, metallic iron being extracted as a reaction product of the carbothermic reduction at 1300 to 180o°C. 10. Method according to one of claims 1-9, characterized in that CO, COg, Ng, water vapor or circulating synthesis gas is used as additive gas. 11. Method according to one of claims 1 - 10. characterized by the fact that the gasification zone is worked with a stoichiometric excess of oxygen in relation to the oxidation to CO. 12. Method according to one of claims 1 - 11, characterized in that in one component the starting materials for the carbothermic reduction are dosed in a targeted manner along an inner wall of the preheating zone and the reduction zone. 13. Device for carrying out the method according to one of claims 1 - 12., characterized by a shaft furnace 6, which from top to bottom consists of an elongated, pre-heating chamber 6c, a reduction chamber 6b and a post-reaction chamber 6d, which open into each other, at least two above;:- each other lying laterally to the reduction chamber 6b adjacent to, and with this openly connected, cylindrical gasification chamber 6a, in which each time nozzle 3 opens for a joint supply of coal dust and oxygen and possibly additive gases, a supply 8 for starting materials of the carbothermic reduction and an exhaust line 9, 12 for raw synthesis gas at the top of the shaft furnace 6, at least one exhaust line 7a, 7b, and post-reaction chamber. 6d for extraction of molten slag and molten reaction product from the carbothermic reduction. 14-. Device according to claim 13, characterized by each time an intermediate bunker 2 for coal dust is connected in front of each nozzle 3, a dedusting device 11 in the extraction line 9, 12 for raw synthesis gas, and return lines 13 for the separated mineral dust from the dedusting device 11 to the individual intermediate bunkers 2. 15. Device according to claim 13 or 14, characterized in that the upper part of the shaft zone 6 is perpendicular to the circularly arranged separation plate 16 for delimiting an annular space 6e between the separation plate 16 and the inner wall of the shaft furnace 6, as well as by at least two transport lines 15 for the supply of a component of the starting materials for the carbothermic reduction through the annulus 6e under the design of an annular protective mantle which protects the inner wall of the shaft 6.