SE0801266A0 - Two stage carburetors using high temperature preheated steam - Google Patents

Description

The application of the technology of partial combustion of incoming carbonaceous materials is widespread. With this technology, the non-combustible gas CO2 is obtained, and since it is not removed, this leads to a dilute synthesis gas, and LCV (low caloric value, a measure of the calorific value of the dry gas mass) of the synthesis gas produced is limited. The presence of CO2 also leads to a low partial pressure for the other gases, which is not favorable for other valuable gasification realions, e.g. the water gas shift reaction. The hydrogen content of the synthesis gas will thus be affected.

The idea of supplying most of the energy using sensible heat for the gasification process has recently been investigated, and positive results have been demonstrated.

The invention of Yoshikawa, Kunio (Sagamihara-shi, JP) and Suzuld, Narumí (Tajimi-shi, JP) in US 2004/0060236, "Apparatus for gasifying solid fuel", describes an economically small-scale gasification system for gasification of solid fuel to pyrolysis gas whereby heated steam / air is introduced into a reformer together with pyrolysed gas which gives a reformed crude gas with a high temperature. In this case, high temperature steam / air will be obtained mainly by using a regenerative heat exchanger with honeycomb structure as described, for example, in US 6,837,910. The temperature of the hot gasification medium must not exceed 1600 K (133 ° C). If pure steam is used for the gasification process using the regenerative heat exchanger, the temperature of the steam will be at the level 700-1250 ° C.

Other known systems that use air / steam / oxygen with a high temperature, as high as 1000 ° C, for a biomass / waste gasification process have also been used (Lucas C., Szewczyk D., Blasiak W., Mochida S., High Temperature Air and Steam Gasification of Densified Biofuels, Biomass and Bioenergy, Volume 27, 6th Edition, December 2004, pp. 563-575). A tar-free hydrogen-rich gas has also been proposed, in which the process is carried out with only steam at a temperature of 1000 ° C and at a conventional pressure of about 1 atmosphere (Ponzio Anna, Yang Weihong, Lucas C, Blaziak W, Development of a Thermal Homogenous Gas System). using High Temperature Agent, CLEAN AIR - International Journal on Energy for a Clean Environment, vol. 7, no. 4, 2007). Another development of the use of high temperature medium for gasification processes, i.e. pure steam for gasification, has been described in e.g. US 2003/0233788, Lewis Frederick Michael (El Segundo, CA) “Generation of an ultra-superheated steam composition and gasification therewith”, proposing a new method that utilizes sensible heat in the steam. It is a method for gasifying carbonaceous materials into fuel gases. It involves the formation of a composition of ultra-superheated steam (USS) mainly containing water vapor, carbon dioxide and highly reactive free radicals thereof, at a high temperature of 1316 ° C to about 2760 ° C. The USS is brought into contact with a carbonaceous material for rapid gasification / reforming thereof. In addition, a controlled amount of oxygen for oxidizing the steam to heat the steam must be used, which increases the operating cost. In addition, when the temperature of the pure steam is lower than 1802 ° C, an excess of steam is required for the conversion of all carbon. The column conversion speed is also slow.

The A11 prior art mentioned above uses only single-stage reactors, either a fixed bed carburettor or a fl unidised bed.

It is known that the thermal conversion of biomass / waste / carbon can be understood as two mainly highly endothermic steps: decomposition of volatile components and tar conversion. As demonstrated in previous studies, 90% of the innehåll content of the total weight of biomass will be released immediately if heated to above 600 ° C. The second step is a tar conversion. To obtain tar-free ash, i.e. 100% tar conversion, a much higher temperature is required for the thermal conversion of tar. Generally, this temperature should be higher than 100 ° C, depending on the ash melting point.

Fixed bed type carburetors are widely used in small-scale energy production (<10 MWfh) thanks to its very simple design and operation. It is obvious that if the design of a gasification reactor with a fixed bed follows these two steps, it would be more efficient from many points of view.

There are extensive studies on this feature for fixed bed carburetors. Secondary air injection into the carburettor is often used. For example, Pan et 4 al. (YG Pan, X. Roca, E. Velo och L. Puianer, i Removal of tar by secondary air injection in fl uidized bed gasiñcation of residual biomass and coal, Fuel 78 (1999) (14), s. 1703- 1709) 88 .7% by weight of tar reduction by injecting seconds of air just above the point of biomass feed into the fluidized bed at a temperature of 840-880 ° C.

Narv et al. (PI Narv, A. Orpso, MP Aznar and J. Corella, Biomass gasification with air in an atmospheric bubbling fl udized bed. Effect of six operational variables on the quality of produced raw gas, Industrial and Engineering Chemistry Research 35 (1996) (7 ), p. 2 1 10-2120) performed secondary air injection into the freeboard of a carburettor with a id unidised bed and observed a temperature increase of about 70 ° C which resulted in a tar reduction from 28 to 16 g / Nm 3.

The Asian Institute of Technology (AIT), Thailand modified a biomass carburetor which resulted in fuel gas with a tar formation of about 50 mg / Nmß, which is about 40 times smaller than a single-stage reactor under similar operating conditions (TA Milne and RJ. Evans, Biomass Gasification). Tars ”: Their Nature, Formation and Conversion. NREL, Golden, CO, USA, Report No. NREL / TP-570-25357 (1988) This concept involves a downstream carburetor with air intakes in two levels. The tar formed during the biomass pyrolysis process passes through a high-temperature bed of residual tar at the bottom and decomposes at the elevated temperature.

Bhattacharya et al. reported in (SC Bhattacharya, MR Siddique and HL, A study on Wood gasification for low-tar gas production, Energy 24 (1999), pp. 285-296) a similar carburettor where tar formed inside the carburettor itself acted as a filter that further significantly reduced tar formation at 19 mg / Nm3 higher CO and Pig concentration in the fuel gas.

Cao (Y Cao, Y Wang, J T Riley, W. Pan, a novel biomass air gasification process for producing tar-free higher heating value fuel gas.) Etc. reported work on a reactor in two areas with an unidentified bed. In this work, a supporting fuel gas and other air stream were injected into the upper area of the reactor to reduce the tar compositions. Experimental results showed a heat value of about 5 MJ / Nmß.

US 6,960,234 B2 issued to Scott E. Hassett presented a multifaceted carburetor and related methods. It is a carburettor that combines a section with fixed bed gasification and one with entrained fl ow gasification. According to this patent, activated carbon can be formed. This patent in fact discloses a fl component (air) injection carburetor US 6,647,903 B2 issued to Charles W. Aguadas Ellis presents a method and apparatus for generating and using combustible gas using two stage air injection, resulting in much less tar. In some ways, activated carbon can also be generated.

JP 6 256 775 introduced complete gasification of organic material in two steps for methane synthesis. In this work, steam and oxygen are used as the gasification medium. The purpose of secondary oxygen / air and / fuel injection in the above studies is to increase the temperature in the freeboard for decomposition of the tar, and probably to improve the vapor reforming reaction. However, the injection of secondary air not only increases the content of diluent components, especially nitrogen, but also reduces the combustible content generated by the gasification. This results in a reduction of low calorific value (LCV) for the gases produced. Injection of secondary air also makes it more difficult to regulate the composition of the product gas.

Another problem is that most of the above-mentioned available fixed bed carburetors can only process coarse solid raw material (typically with a diameter greater than 0.5 mm), since granular particles lead to clogging of the cavities between the coarse particles, and also to difficulty in using liquid carbonaceous material.

In order to be able to produce combustible gases with a medium and high low calorific value (LCV) and to be able to gasify both solid and fl surface / fine-grained raw materials at the same time, and also to produce other valuable materials, such as activated carbon, a new fixed bed carburetor is proposed here. The carburettor is defined in claim 1. A method of gasifying a coarse-grained carbonaceous feedstock with a two-stage carburettor with two reactors, to obtain synthesis gas, optionally together with activated carbon, where no oxygen is fed to the reactor in the first stage, but only preheated steam with a temperature of at least 700 ° C is also described. The method is stated in claim 5.

SUMMARY OF THE INVENTION For a two-stage carburetor according to the prior art, described in JP 6256775, stated in the preamble of claim 1, the above-mentioned objects have been fulfilled by means of the technical features according to the core-drawing part of said claim.

Accordingly, in one aspect, the invention relates to a two-stage carburetor.

In the carburettor according to the invention, gasification of solid coarse-grained material on the one hand and solid fine-grained and / or surface material on the other hand is made possible at the same time.

Carbonaceous coarse-grained material is fed to the first reactor and carbonaceous (waste) liquid and / or carbonaceous non-granular solid material is fed to the second reactor.

In a preferred embodiment of the two-stage carburettor, a tapered part with a reduced cross-section is arranged at the bottom of the first reactor and / or at the top of the second reactor, and preferably also at the bottom of the second reactor.

In a further preferred embodiment of the two-stage carburettor, one or more, and preferably all inlets for steam, air, oxygen and carbonaceous (waste) liquid and / or carbonaceous fine-grained solid material lead into the carburettor tangentially in corresponding parts of the carburettor, which parts has an inner circular cross section.

In a further preferred embodiment of the two-stage carburettor, the inlets for carbonaceous (waste) liquid and / or carbonaceous fine-grained solid material comprise at least two inlets separated by a maximum distance from each other along the circumference of the inner circular cross-section.

In another aspect, the invention relates to a process for gasifying a coarse-grained carbonaceous feedstock, using a two-stage carburettor with two reactors, for producing synthesis gas, optionally together with activated carbon. Such a method is set out in claim 5.

According to a preferred embodiment of the process, externally generated preheated steam with a temperature of at least 70 DEG C. is also fed into the reactor in the second stage. With this embodiment, the internal combustion in the exhaust gas can be kept to a minimum, since the required energy is supplied from an external source. Consequently, the supply of air or oxygen for heat generation by internal combustion is not required in this embodiment. When air or oxygen is not supplied to the reactor in the second stage, the yield of activated carbon can also be maximized.

According to a further preferred embodiment of the process, air is also supplied to the second reactor (i.e. in addition to the high temperature steam). With this embodiment, synthesis gas of particularly high quality can be obtained, since carbon is also converted to CO, and not only to activated carbon. In addition, depending on the vapor / air ratio, combustion can still be avoided (i.e. formation of CO 2). At the same time, the CO-activated carbon ratio can also be regulated by regulating the steam / air ratio.

According to a further preferred embodiment of the process, pure oxygen (instead of air) is used. According to this embodiment, the method can be used for industrial purposes. The need for separation of by-products is also minimized, and undesired dilution of the gaseous product is kept to a minimum.

Additional embodiments and advantages will be apparent from the detailed description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a system fate diagram that generally illustrates the inventive gasification process for biomass and solid waste.

Figure 2 shows a cross-sectional view of an embodiment of the carburettor 21. Figure 3 is a plan view of the carburettor showing the tangential injection of surface raw material with the inlets 19a and 19b.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS THEREFORE The underlying idea of the invention is to separate the carburetor into two steps: a first step for decomposition of volatile components, the first step using only externally generated preheated 700 steam C-1000 ° C), and a second step for thermal conversion of tar, preferably using a mixture of air and steam preheated to a high temperature (above 700-1400 ° C) as shown in Figure 1.

In the first reactor, the energy used to decompose volatile materials from both the sensible heat of the steam and from the hot current coming from the second reactor is supplied. The temperature in this reactor is regulated to a level of at least 600 ° C by quantity of and temperature of the steam.

In this reactor, the decomposition process of volatile material from the mixture of high-temperature steam and raw material (biomass) takes place, after the biomass has been heated by high-temperature steam, according to: carbonaceous raw material heat from high-temperature steam (ll _---> fl volatile material (Cml-In, CO, H2 , CO 2, O 2, etc.) + tar At the same time, due to the presence of steam, a reaction takes place with the volatile components: CmHn + H 2 O <-> CO + H 2 (2) CO + HgO-a CO 2 + Hz (3) Some oxygen released from the pyrolysis and from the other reactor reacts according to: cmHn + (m / z + n / 4) o2-> mco + n / 2H2o (4) CO +% O2 _) CO2 (5) H2 + % O2 _) H20 (Ö) CO + HgÛ-á CO2 + Hg (7) Since the reactor temperature in the first stage reactor is regulated to a level of at least 600 ° C, the residence time is regulated, the gases in the first reactor are in an environment which to a very large extent lacks oxygen, solid and surface residual tar will not react with oxidizing agents. Thereafter, all of these will fall into the second reactor by gravity.

In the second reactor, the energy used for the tar conversion process is preferably supplied from sensible heat of the mixture of steam and air, and partial oxidation of tar. To achieve tar-free conversion, the temperature in the second reactor should be higher than the ash melting point, to cause the ash to form slag. For wood biomass, it can normally be 1300 ° C.

The main reactions are when there is no injection of other raw material (fl surface and fi sensitive particles): Gasification: C + O 2 => CO 2 -393.5 kJ / mol (8) C + H 2 O => CO + H 2 + 131.3 kJ / rno1 (9) C + 21-120 => CO; + H2 +90.2 kJ / mol (10) - Partial oxidation: C + 0.502 => CO -110.5 kJ / mol (1 l) - Boudouard reaction: C + CO2 => 2CO -172.4 kJ / mol (12) - Water gas shift: CO + H 2 O => CO 2 + H 2 -41.1 kJ / mol (13) - Methanation: CO + 3H 2 => CH 4 + H 2 O -206.1 kJ / mOI (14) - Hydrogenation: C + 2H2 => CI-L; -75 kJ / mol (15) When a second raw material (fl surface and incoming particles) is injected into the second reactor, all reactions from (1) to (15) will take place.

Many reactions occur simultaneously and it is difficult to control the process exactly as pointed out here. However, by carefully selecting the process parameters (temperature, reaction time and oxygen / meadow conditions), it is possible according to the invention to maximize certain desired products, such as activated carbon and synthesis gas.

In addition, the activated carbon can be treated as a co-preparation from thermal conversion of carbon-based materials by this invention. The production of activated carbon usually involves two steps: charring the raw material in the absence of oxygen at high temperature (500-100 ° C) to eliminate the majority of oxygen and hydrogen and activating the charred product at a higher temperature in the presence of oxidizing gas such as water, carbon dioxide or both. Activation must be performed under well-controlled conditions to obtain the desired conversion.

According to the invention, the raw material is first gasified by means of pure high-temperature steam (at a level of at least 600 ° C) in the first reactor, after which the carbon is preferably activated in the second reactor by means of high-temperature steam.

Here, high-temperature steam, and optionally air or oxygen, (above 700 ° C) is obtained mainly by using a regenerative heat exchanger with a honeycomb structure as explained e.g. in U.S. Patent No. 6,837,910, or co-pending U.S. Patent Application Laid-Open No. 6 1/01131, the contents of which are incorporated herein by reference.

Figure 2 illustrates a cross-sectional view of the carburetor 21. Carbonaceous feedstock enters the reactor at the top, through a feed inlet 2, and continues downward as it moves through the first reactor 3, then passes the grid 8, then enters the second reactor 4, and then passes the grid 5 until it becomes a molten ash on the bottom 6. The raw material may include biomass, coal, municipal solid waste, or any combination thereof. In the first reactor 3, the raw material is heated by a combination of sensible heat caused by the high-temperature steam (above 700 ° C), and sensible heat carried by the flue gases obtained by tar oxidation and gasification in the second reactor 4. High-temperature steam passed through the pipe 7 for gasification of the raw material in this reactor enters a neck 20 through an opening (openings) 11. The amount of high temperature steam supplied through the opening 7 is set so that the temperature at point 3 (first reactor) is kept between 600-900 ° C, and preferably above 700 ° C.

At the point around 8 (grid), hot combustion furnaces can occur when excess oxygen burns with pyrolysis gases released from the raw material.

The temperature in reactor 3 is regulated by the temperature and the rate of fate of the steam injected from point 7, and the temperature and quantity of excess oxygen from reactor 4. The residence time of the raw material in reactor 3 is mainly controlled by the gap in the grid 8.

In order to obtain a good mixing between gasification medium (steam) with the raw material, a neck 20 is preferred. The diameter of the neck is usually smaller than that of the core in the reactor 3. The slope 14 should be around 45-60 °. The diameter of the steam inlet opening should be 2-3 times smaller than that of the neck 20.

After volatile components have been decomposed from the fuel by means of high temperature steam in the first reactor 3, the residue fixert carbon has become activated carbon, tar and solid ash material, which continues to surface downwards through the grid 8, then enters a neck 20, then into the second reactor 4, where they are oxidized and gasified by means of a mixture of high temperature air and vapor. The temperature in the reactor is further increased to a temperature which is marginally below the softening point of the ash for the fuel in question at the grid 5. The tube 9 carries the mixture of high temperature air and steam to the opening 10, then enters the second neck 18. For wood - pellets from Sweden extend the ash softening point from 1350-1400 ° C. During operation, the maximum peak temperature in reactor 4 is kept at least 50 ° C below the ash softening point, with 100 ° C below being the normal maximum condition. 12 The temperature in reactor 4 is regulated by the preheating temperature, the rate of fate and the ratio of steam to oxygen in the mixture, and the ratio of steam to carbon.

The diameter of the second neck 18 is usually smaller than the diameter of reactor 4, and also smaller than that of the first neck 20. The slope 17 should be around 45-60 ° C. The diameter of the steam injection opening should be 3-5 times smaller than that of the neck 18.

The ash falls in 6 through 18 and is taken out in batches.

The synthesis gas flows out through the outlet pipe 12. Since the temperature in the first reactor is high enough, and steam is also present, most of the tar is destroyed and converted into synthesis gas. The main chemical constituents of the synthesis gas are hydrogen, carbon monoxide and methane as well as carbon dioxide.

The new design of the carburettor has the ability to advantageously regulate the ratio of hydrogen to carbon monoxide in the synthesis gas, since the carburettor has the ability to have control over the ratio of steam to oxygen in the carburettor within wide limits.

By regulating the temperature in the second reactor 4, to around 700 ° C, i.e. In addition, at the same temperature as in the first reactor 3, all tar and oils of high temperature steam are consumed. This converts most of the fixed carbon to activated carbon in the reactor. It can therefore also generate activated carbon.

The invention can also be used to produce activated carbon. There are two methods by which activated carbon is formed in the carburetor. The first is one in which only the first reactor is used, i.e. only high-temperature steam is injected through pipe 7. The high-temperature mixture of steam and air from pipe 9 is closed. Another method is to have both reactors running, but to inject only high-temperature steam from pipe 9.

In this case, activated carbon is collected directly in the dry state. The second method can give high quality of activated carbon from tar, since the high temperature steam injected from the pipe 9 causes the pores of the activated carbon to open in the second reactor 4. The size (pore diameter) can be controlled by the temperature of the steam in the reactor 4.

Usually a higher temperature of the steam increases the number of pores in the activated carbon.

The invention can thus bring about the formation of two products (gas and activated carbon) from the raw material. The proportion of products can be determined in accordance with the types of raw materials, the price of the products and so on.

The invention can also be used to treat both coarse-grained particles (diameter greater than 0.5 cm) of carbonaceous materials and fine-grained particles and / or surface raw materials.

Figure 3 shows a cross-sectional view of the carburetor 21, showing the tangential injection of raw material of liquid / granular particles. Two injection lances 19 (19a and 19b) are shown connected to the reactor 4. Liquid raw materials, such as liquid residues collected after a microwave pyrolysis process for Automotive Shredder Residue-ASR, and granular or powdered raw materials can be injected into the reactor raw material. enters the reactor 4 tangentially and is mixed with high temperature air / steam coming from the grid 5. The tangential injection can increase the residence time of the liquid-form or fincoma raw material. The entrained exhaust gases pass through the upper fixed bed grid 8, then enter the reactor 3 before leaving the carburettor at the outlet pipe 12. The injection port 19 should be located at the lower part of the hard in the reactor 4 to increase the residence time. For a small-scale carburettor, the location of this injection opening (s) is usually 10 cm above the sloping wall 17.

The residence time can be regulated by the injection speed, the angle of the injection laris in relation to the carburettor.

In a preferred embodiment, the walls of the carburettor consist of two layers: an outer steel height, 5.0 mm thick, and an inner housing of ös brittle ceramic insulation, preferably a high temperature resistant, high quality ceramic. The ceramic used at the wall 13, 14 can withstand operation at a maximum temperature of 140 ° C. This material is composed of AlgOg 45%, SiOg 36%, FeqOg, 0.9% and CaO 16%. The ceramic used at the walls 15, 16 and 17 is preferably adapted to withstand a higher temperature of 1400-1500 ° C. The maximum permissible operating temperature for this wall material is 1600 ° C. The composition of the material is AlgO 2, 61%, SiO 2 26%, Fe 2 O 3, 0.5%, CaO 2.6 ° / o, ZrO 2 2.95%, and BaO 3.3%. The ceramic materials are supported by a steel casing.

In a preferred embodiment, refractory ceramic tubes such as grids 8 and 5 are used.

The composition of these ceramic tubes can e.g. be 97% ZrO 3, and 3% MgO.

A high temperature mixture of air / steam through the pipe 9 enters the throat 18 located below the grid 5. This high temperature mixture of air and steam can keep the ash in a molten state in the throat 6, finally falls into the bottom 6, and can be taken out in batches.

Example 1: 97 kg / h wooden pellets with a diameter of around 8 mm are fed into the first reactor from the top 1 by gravity at room temperature (15 ° C). The properties of the wood pellets are shown in Table 1. 90 Nm3 / h of the highly preheated mixture of air and steam is injected into the carburettor through the inlet 9. The temperature of the preheated mixture is 1332 ° C. The oxygen concentration in this mixture is 9% (vol), and the vapor concentration in the mixture is 51% (vol). This highly preheated mixture of air and steam passes through reactors 4 and 3, then hits the droplets injected from 1. The resulting combustible gas flows out of 12. The temperature of the synthetic gas at outlet 12 is 554 ° C. The low calorific value (LI-IV) of the synthesis gas obtained is 8.1 MJ / Nm3. The concentration of hydrogen, CO and Cl-Li in the synthesis gas produced is 16.4%, 25.1% and 4.3% respectively (volume in weight).

Table 1 Primary and elemental analysis of the raw materials used Primary analysis Tfäpeiietaf (WP) Total moisture content (ss1s717o) 8% Ash content (SS-187171) 0.5-0.6% (dry) LHV (SS-ISO562) 17.76 MJ / kg (as obtained) Volatiles (SS-ISO) 84% (dry) Density 630-650 kg / m3 Elemental analysis (dry compositions) Wood pellets Sulfur (SS-187177) S 0.01-0.02 ° / ø Carbon ( Leco-600) C 50% Hydrogen (Leco-600) H 6.0-6.2% Nitrogen (Leco-600) N <0.1% Oxygen (calculated) O 43-44% Ash melt temperatures (oxidizing conditions) Wood pellets 1350 - 1400 ° C 1450- 1500 ° C 1 500 ° C 1500- 1550 ° C Initial deformation, IT Softening, ST Hemispheric, HT Temperature at liquid state, FT Example 2: 60 kg / h of waste-derived fuel (RDF), a pelletized fuel made from paper bers mixed with other substances such as textiles, wood chips and plastics, was used as a raw material with a diameter of about 8 mm, and was fed into the first reactor from the top 1 by its weight, ie. by the action of gravity, at room temperature (15 ° C). The properties of the trawl pellets are shown in Table 1. 101 Nm3 / h of the preheated mixture of air and steam is injected into the carburettor 9. The temperature of the preheated mixture is 1447 ° C. The oxygen concentration in this mixture is 10% (vol), and the vapor concentration in the mixture is 4% (vol).

This highly preheated mixture of air and oxygen passes through reactors 4 and 3, then hits the wood pellets injected from 1. The resulting combustible gas flows out of 12. The temperature of the synthesis gas at outlet 12 is 804 ° C. The low calorific value (LHV) of the synthesis gas formed is 9.5 MJ / Nmß. The concentration of hydrogen, CO and CH4 in the synthesis gas formed is 10.4%, 15.3% and 6.4% respectively (volume in the dry state).

Table 2 Primary and elemental analysis of the raw materials used Primary analysis Waste-derived fuel (RDF) 2.9% 6.0% (dry) 26,704 MJ / kg (as obtained) 84.4% (dry) 472 kg / m3 Total moisture content (SS 187 170) Ash content (SS- 187171) LHV (SS-ISO562) Volatiles (SS-ISO) Density Elemental analysis (dry compositions) RDF Sulfur (SS- 187 177) S 0.09% Carbon (Leco-600) C 63.3% Hydrogen (Leco-600) H 8.9% Nitrogen (Leco-600) N 0.3% Oxygen (Calculated) O 20.95% Ash melt temperatures (oxidizing conditions) RDF Initial deformation, IT 1210 ° C Softening, ST 1220 ° C Hemispherical, Autumn 1230 ° C Temperature at fl surface state, FT 1240 ° C

Claims (10)

10 15 20 25 30 17 PATENT REQUIREMENTS A two-stage carburettor (21) for producing synthesis gas, and optionally activated carbon, starting from a coarse-grained carbonaceous raw material, which carburettor comprises: - an inlet (7) for steam; an inlet (9) for steam, optionally together with air or oxygen; - a first, upper reactor (3), provided with an inlet (2) for a coarse-grained carbonaceous raw material (1), and an outlet (12) for synthesis gas; and - a second, lower reactor (4); the first and second reactors being separated by a means (8) for limiting the passage of the coarse-grained carbonaceous feedstock from the first reactor to the second reactor by the action of gravity, the first reactor being capable of being operated at a temperature at least 600 ° C, and the second reactor is capable of being operated at a higher temperature, characterized in that the second reactor is provided with an inlet (19) for a granular solid carbonaceous feedstock and / or a liquid carbonaceous feedstock, inlet (7 ) is located near the bottom of the first reactor, so that preheated steam with a temperature of at least 700 ° C can be fed to the first reactor from below via inlet (7), and from the fact that inlet (9) is located near the bottom of the second reactor, so that preheated steam with a temperature of at least 700 ° C, optionally together with preheated air or oxygen with a temperature of at least 700 ° C, can be fed to the second reactor from below via inlet (9). Two-stage carburettor according to claim 1, wherein a neck part (20, 18) with a reduced cross-section is arranged at the bottom of the first reactor and / or at the top of the second reactor, and preferably also at the bottom of the second reactor. Two-stage carburettor according to claim 1 or 2, wherein one or more and preferably all of the inlets (7, 9, 19) open tangentially into the carburettor in corresponding parts (20, 18, 16) of the carburettor, which have internal circular cross section. 10 20 25 30 18 The two-stage carburettor according to claim 3, wherein the inlet (19) comprises at least two inlets (19a, 19b) separated by a maximum distance from each other along the circumference of the circular cross-section. A process for gasifying a coarse-grained carbonaceous feedstock using a two-stage carburetor with two synthesis gas production reactors, optionally together with activated carbon, comprising the steps of: (a) feeding a coarse-grained carbonaceous feedstock to the reactor in the first step; of the carburetor; (b) the coarse-grained carbonaceous feedstock is subjected to steam in the reactor in the first stage at an operating temperature of at least 600 ° C in the reactor, to effect gasification of the carbonaceous feedstock; (c) any solid and liquid carbonaceous materials obtained from step (b) are exposed to steam and air or steam and oxygen in the second stage reactor operating at a higher operating temperature than in step (b) to obtain any combination of the following: activated carbon; CO; CO 2; and combustion heat; characterized in that no oxygen is fed to the first stage reactor, but only preheated steam with a temperature of at least 700 ° C. A process according to claim 5, comprising a further step (d) according to which a granular solid carbonaceous, or liquid carbonaceous raw material is simultaneously fed to the reactor of the second stage in the carburettor. A process according to claim 5 or 6, wherein (c) the steam is preheated in steps to a temperature of at least 700 ° C. A process according to claim 7, wherein the ratio of steam / air or steam / oxygen used in step (c) is selected so that the internal combustion is minimized, and so that the yield of CO and / or activated carbon is maximized. A method according to any one of claims 5-8, wherein oxygen is used instead of air. 19 A method according to claim 7 or 8, wherein no air or oxygen is supplied to the carburettor. l 15 15 SAM SUMMARY A carburettor is described which combines two reactors and which uses externally generated preheated steam of high temperature which is injected into the first reactor, where the heating need for gasification is covered by sensible heat from the steam. The carburettor can produce synthesis gas with medium and high low calorific value. The first reactor is a solid bed gasification section where coarse-grained raw material is gasified, and the second reactor is a gas-fired section with entrained bed where liquid and granular raw material is gasified. Solid coarse-grained raw material is first freed from volatile components in the first fixed-bed reactor in the carburettor by means of high-temperature vapor, and is then exposed in the second reactor to a higher temperature sufficient to decompose and destroy tar and oils. Activated carbon can be produced as a simultaneous product. The carburettor can be used with various solid and surface raw materials. The carburettor has the ability to gasify these different raw materials simultaneously.