DE102005042640A1 - Process and apparatus for producing synthesis gases by partial oxidation of slurries produced from ash-containing fuels with partial quenching and waste heat recovery - Google Patents

Abstract

The invention relates to a method and an apparatus for the gasification of solid fuels such as hard coal and coke such as those made from hard coal, lignite and biomass and petroleum coke, which are finely ground and mixed together with water or oil to form fuel-liquid suspensions, so-called slurries and their gasification together with a free oxygen-containing oxidizing agent by partial oxidation at pressures between ambient pressure and 100 bar and temperatures between 1200 and 1900 ° C in an entrained-flow reactor, consisting of the process steps of slurry production and supply to the reactor, gasification in an entrained-flow reactor with a cooled reaction chamber contour , Partial quenching, waste heat recovery and wet or dry dust separation, the raw gas being pretreated in such a way that it can be fed to further technological stages such as raw gas conversion or desulfurization.

Description

The The invention relates to a gasification process according to the preamble of the first claim and a device for carrying out the Process.

The process consists of the process steps slurry preparation, fuel supply, gasification reaction, partial quenching, gas scrubbing and partial condensation, gas scrubbing and partial condensation can be replaced by a mechanical dust separation, to produce CO and H ₂ -containing gases by partial oxidation of dusty, ash-containing fuels with a free oxygen containing gasification agent at high temperatures and elevated pressure.

Around To reach long operating times must the pressure jacket of the gasification reactor reliable against the action of raw gas and against the high gasification temperatures protected from 1,200-1,900 ° C. This is done by limiting the reaction or gasification space through a chilled Pipe screen, which is mounted in the pressure jacket. The annular gap between pipe screen and pressure jacket is rinsed.

Of the Fuel is produced as slurry by pumping to gasification pressure brought and fed at the top of the reactor via burner. It can simultaneously gasified one or more fuels or coals become. The raw gas leaves the Gasification room together with the liquefied slag at the bottom End of the reactor and is then injected by injecting Water at 700 ° C up to 1100 ° C partially cooled and freed of entrained particulate matter after waste heat recovery. following the scrubbed raw gas is fed to further treatment stages.

In the technology of gas generation, the autothermal entrained flow gasification of solid, liquid and gaseous fuels has been known for many years. The ratio of fuel to oxygen-containing gasification agents is chosen so that due to the synthesis gas quality higher carbon compounds to synthesis gas components such as CO and H _{2 are} completely split and the inorganic components are discharged as molten slag, see J. Carl, P. Fritz, NOELL- CONVERSION PROCESS, EF-Verlag for energy and environmental technology GmbH, 1996, p. 33 and p. 73.

According to various systems introduced in the art, gasification gas and molten slag can be separated or discharged together from the reaction space of the gasification device, such as DE 19718 131 A1 shows. For the inner confinement of the reaction space structure of the gasification system, both refractory lined or cooled systems have been introduced, see DE 4446 803 A1 ,

EP 0677 567 B1 and WO 96/17904 show a method in which the gasification space is limited by a refractory lining. This has the disadvantage that the refractory brickwork is detached by the liquid slag produced during the gasification, which leads to rapid wear and high repair costs. As the ash content increases, this wear process increases. Thus, such gasification systems have a limited duration to the renewal of the lining. In addition, the gasification temperature and the ash content of the fuel are limited. The feed of the fuel as a coal-water slurry brings significant efficiency losses, see C. Higman u. M. van der Burgt, "Gasification", ELSEVIER, USA, 2003, which can be reduced or avoided by using oil as a carrier medium or by preheating the coal-water slurries, further describes a quenching or cooling system in which the hot gasification gas and the liquid slag are discharged together via a guide tube which starts at the lower end of the reaction space and passed into a water bath.This common removal of gasification gas and slag can lead to obstruction of the guide tube and thus to the restriction of the availability.

DE 3534015 A1 shows a method in which the gasification media fine coal and oxygen-containing oxidant are introduced through several burners in the reaction space so that the flames deflect each other. At the same time, the gasification gas flows upwards, laden with fine dust, and the slag flows down into a slag cooling system. As a rule, a device for indirect cooling using the waste heat is provided above the gasification space. By entrained liquid slag particles, however, there is a risk of deposition and occupancy of the heat exchanger surfaces, which leads to the obstruction of heat transfer and possibly to blockage of the pipe system or erosion. The risk of constipation is counteracted by the hot raw gas is cooled with a recirculating cooling gas.

By Ch. Higman and M. van der Burgt in "Gasification", page 124, published by Elsevier 2003, a process is presented in which the hot gasification gas leaves the gasifier together with the liquid slag and enters directly into a waste heat boiler arranged vertically underneath, in which the raw gas and the slag are cooled by using the waste heat for steam generation Slag accumulates in a water bath, the cooled raw gas leaves the waste heat boiler sideways. The advantage of waste heat recovery according to this system faces a number of disadvantages. Mention may be particularly the formation of deposits on the heat exchanger tubes, which lead to the obstruction of heat transfer and corrosion and erosion and thus lack of availability.

CN 200 4200 200 7.1 describes a "Solid Pulverized Fuel Gasifier" in which the coal dust is pneumatically supplied is and gasification gas and liquefied Slag over a central tube is introduced into a water bath for further cooling. This central exhaustion in said central tube is vulnerable against blockages that disrupt the overall operation and availability reduce the overall investment.

outgoing From this prior art, it is an object of the invention, a possibility which, given a reliable mode of operation, provides the different Ash content of the fuels takes into account and high availability having.

These Task is performed by a gasification process according to the characteristics of first claim and a device according to claim 13 solved. Subordinate claims advantageous embodiments the invention again.

The gasification process for the gasification of solid ash-containing fuels with an oxygen-containing oxidant in a trained as a fly-reactor gasification at pressures between ambient pressure and 100 bar, wherein the reaction space contour is limited by a cooling system, the pressure in the cooling system is always kept higher than the pressure in the reaction chamber , characterized by the following features:
The fuel, z. As hard coal, lignite and lignite coke and biomass coke and / or petroleum coke or their mixtures are crushed to a grain size <500 microns, preferably <200 microns and with the addition of liquids such as water or oil to a fuel-water or fuel Oil suspension, a so-called slurry, mixed. When using water as the carrier medium is achieved with the addition of surfactants stable solids concentrations up to 70 Ma%. These are brought by suitable pumps to the desired gasification pressure up to a maximum of 100 bar and fed via suitable burners, which are attached to the head of the gasification reactor, the gasification reaction. The fuel concentration in the slurry as well as the flowing amount of slurry are monitored, measured and controlled by measuring, regulating and monitoring devices. The burner is simultaneously fed to a free oxygen-containing oxidant and the fuel slurry is converted by partial oxidation in a Rohsynthesegas. The gasification takes place at temperatures between 1,200 and 1,900 ° C at pressures up to 100 bar. The reactor is equipped with a cooling screen consisting of gas-tight welded and water-cooled pipes.

The name is Raw synthesis gas leaves together with the formed from the fuel ash liquid slag the gasification reactor and enters a space arranged vertically below, in which by injecting water or by supplying a cool gas a partial quenching, ie a cooling to temperatures between 700 ° C and 1100 ° C he follows. At this temperature, the entrained liquid slag is cooled so far that they can no longer adhere to the metallic surfaces. That on the Temperatures of 700 ° C and 1,100 ° cooled raw gas thereafter comes together with the equally cooled solid Slag in a waste heat boiler to use the tangible Heat to Steam production. By this previous partial quenching or partial cooling is prevents the risk of caking of slag to the waste heat cooling pipes or severely limited. That for the Teilquenchung required water or recycled gas condensate is supplied via nozzles, the are located directly on the jacket. The cooled slag collects in a water bath placed at the bottom of the waste heat boiler is. The cooled to about 200 ° C-300 ° C raw gas leaves laterally the waste heat boiler and enters a raw gas scrubbing, the expedient manner as Venturi wash is trained. Here, the entrained dust is up to a particle size of approx. 20 μm away. This degree of purity is not enough, then catalytic Processes such as a raw gas conversion perform. there is further to consider that in addition Salt mist in the raw gas entrained be that while the gasification of the fuel dust be released and removed with the raw gas. To both the fine dust <20 microns and removing the salt mist, the scrubbed raw gas is a condensation stage fed in the raw gas indirectly by 5 ° C up to 10 ° C chilled becomes. In this case, water is condensed from the water vapor-saturated crude gas, which absorbs the described fine dust and salt particles. In a subsequent Separator is the condensed the dust and salt particles contained Water separated. The purified crude gas can then be directly, for example, a raw gas conversion or desulphurisation plant, supplied become.

Instead of washing and Kondensststu Fe can be provided at 200 ° C to 300 ° C working mechanical dust separation, with centrifugal or filter systems can be used.

in the Below, the invention of 3 figures and an embodiment explained in more detail. The Figures show:

1 : Block diagram of the technology

2 : Gasification reactor with partial quenching and vertically arranged waste heat boiler

3 : Gasification reactor with partial quenching and adjacent waste heat boiler

A coal amount of 320 t / h with a composition of C 71.5% H 4.2% O 9.1% N 0.7% S 1.5% Cl 0.03% an ash content of 11.5 Ma% and a moisture content of 7.8 Ma% is to be gasified at a pressure of 40 bar. The calorific value of the coal is 25,600 kJ / kg. The gasification takes place at 1450 ° C. For gasification, an amount of oxygen of 245,000 m ³ iN / h is needed. The coal is first fed to a state-of-the-art grinding plant, in which the comminution is carried out to a granulation between 0 and 200 microns, then with water with the addition of surfactants to a stable coal dust-water suspension, the so-called slurry in a special facility 1 to 1 to be mixed. The solids concentration in this slurry is 63% by mass, the amount of slurry is 465 t / h. The slurry is brought to the desired gasification pressure at 100 bar by means of a suitable for the promotion of solid-liquid suspensions pump and via the delivery line 1.1 the burner of the gasification reactor 2 to 1 supplied, the amount is monitored, measured and regulated. To save oxygen, the slurry before feeding to the gasification reactor 2 depending on the gasification pressure preheated to 400 ° C.

The gasification reactor is in the 2 and 3 shown. The about the support line 1.1 The 465 t / h slurry flowing into the gasification reactor is communicated with the via line 2.1 inflowing oxygen amount of 245,000 m ³ iN / h in the gasification room 2.3 subjected to partial oxidation at 1450 ° C to give 565,000 m ³ iN / h of crude gas of the following composition: H ₂ 18.5% by volume CO 70.5% by volume CO ₂ 6.1% by volume N ₂ 2.3% by volume NH ₃ 0.003% by volume HCN 0.002% by volume H ₂ S 0.5% by volume COS 0.07% by volume

The gasification room 2.3 is from a cooling screen 2.4 limited, which consists of a gas-tight welded, water-cooled pipe system. The raw gas flows together with the liquid slag via the outlet opening 2.5 in the room 3.1 for partial quenching / partial cooling of the raw gas to temperatures of 700 ° C-1,100 ° C. At this temperature, in addition to the raw gas and the slag cooled down so far that they are not in the pipes 4.1 after 1 can deposit subsequent heat recovery boiler. The in the waste heat boiler 4 generated steam is used in the process for preheating the oxygen-containing oxidant or as a gasification moderator for preheating the slurries. The slag collects in a water bath 4.2 , which is located at the bottom of the heat recovery boiler and is over 4.3 discharged. The raw gas leaves the waste heat boiler 4.4 and gets into the raw gas scrubber 5 to 1 , The waste heat boiler 4 can after 3 directly under the gasification reactor 2 and partial quenching 3 but also, how 4 shows, be arranged adjacent. In this case, it is under both the partial quenching 3 a slag deduction 4.3 as well as below the waste heat boiler 4.6 , That the waste heat boiler 4 over the exit 4.4 leaving raw gas then passes into the crude gas scrubbing 5 to 1 , which is designed as a controllable Venturi wash and applied with about 100 m ³ / h of wash water. The wash water is usually freed from the absorbed solids and fed back to the Venturi wash. The washing water can be preheated to moisten the raw gas during washing at the same time. In order to remove fine dust <20 μm as well as salt mist not separated in the Venturi wash, the water-washed crude gas becomes a partial condensation 6 to

1 subjected to, wherein the raw gas is cooled indirectly by 5-10 ° C. By condensing water vapor during cooling, the finest dust and salt particles are absorbed and thus removed from the raw gas. The crude gas purified from solids then has the following composition: H ₂ 13.4% by volume CO 51.4% by volume CO ₂ 4.5% by volume N ₂ 1.5% by volume NH ₃ 0.0022% by volume HCN 0.0012% by volume H ₂ S 0.36% by volume COS 0.05% by volume H ₂ O 37,30 Vol.%

The purified wet raw gas quantity is 775,000 Nm ³ / h. It can be fed directly to a crude gas conversion or other treatment stages.

1

slurry preparation and feeding

1.1

Slurryleitung

2

reactor

2.1

management for oxygen

2.2

burner

2.3

gasification chamber

2.4

cooling screen

2.5

outlet opening

3

quench

3.1

quench

3.2

Nozzles in 3

3.4

Transfer line from 3 to 4

4

waste heat boiler

4.1

Cooling tubes in the waste heat boiler 4

4.2

Water bath with slag in 4

4.3

Slag vent off 4

4.4

Opening off 4 to the crude gas scrubber 5

4.5

Water bath with slag 4

4.6

Slag vent off 4

5

Rohgaswäscher

6

partial condenser

Claims (21)

Process for the gasification of solid fuels such as coal and coke such as hard coal, lignite, biomass and petroleum coke in flight with an oxidant containing free oxygen by partial oxidation at pressures between ambient pressure and 100 bar and temperatures between 1,200 to 1,900 degrees, consisting of the Process steps slurry production and supply, gasification by partial oxidation in a reactor with cooled reactor space contour, partial quenching, crude gas scrubbing and partial condensation, whereby crude gas scrubbing and partial condensation can be replaced by a working above the dew point dry mechanical dust removal, wherein: - a dust with a particle size <200 microns, preferably <100 .mu.m, in a special system with water with the addition of a surfactant to a fuel-water slurry with a solids concentration of 40-70 Ma% mashed and brought by pump delivery to the gasification pressure of 100 bar where the slurry can be preheated to temperatures of up to 400 ° C, - via a delivery pipe ( 1.1 ) the reactor 2 supplied slurry together with a free oxygen-containing oxidant in the reaction space ( 2.3 ) whose contour is covered by a cooling screen ( 2.4 ) is subjected to a partial oxidation, wherein the ash of the fuel is melted and, together with the hot gasification gas via the drainage device ( 2.5 ) into the quench space ( 3.1 ) of the quench cooler ( 3 ), - the partial quenching takes place with cooling of the raw gas to temperatures between 700 and 1100 ° C, - the partially quenched raw gas in a waste heat boiler ( 4 ) is cooled with steam generation to temperatures between 150 and 400 ° C, - the cooled raw gas then for the deposition entrained dust of a raw gas scrubbing ( 5 ) and a partial condensation ( 6 ) or a dry mechanical dust separation by centrifugal force or filter is subjected. - The cooled and freed from dust crude gas is then fed to further treatment stages such as a crude gas conversion or desulfurization. A method according to claim 1, characterized in that the crude gas scrubbing 5 is designed as a single or multi-stage venturi wash. Process according to claims 1 and 2, characterized that the venturi wash with fresh water or recycled condensates is fed, the cooling of the gas accumulates. Process according to claims 1 to 3, characterized in that the waste heat boiler ( 4 ) is operated at temperatures of 700 to 1100 ° C. Process according to claims 1 to 4, characterized in that the crude gas scrubbing ( 5 ) at temperatures of 150 to 300 ° C. Process according to claims 1 to 5, characterized that the Venturi scrubbers of circulating water or recycled condensate be fed. Process according to claims 1 to 6, characterized in that the fuel as fuel-water Slurrie the reactor ( 2 ) is supplied. Process according to claims 1 to 7, characterized in that the fuels the Gasification reactor ( 2 ) are supplied via one or more burners. Process according to claims 1 to 8, characterized in that the granulated slag is conveyed via one or more outlets ( 3.6 ) of the quench space ( 3.5 ) is discharged. Process according to claims 1 to 9, characterized in that the partially quenched crude gas is the quenching space ( 3.5 ) via one or more gas outlets ( 3.4 ) leaves. Process according to claims 1 to 10, characterized that at the same time one or more types of coal are gasified. Process according to claims 1 to 11, characterized in that the amount of slurry in the delivery pipe ( 1.4 ) is measured, monitored and regulated. Apparatus for carrying out a process according to claims 1 to 12, characterized by: a plant for producing and supplying slurry ( 1 ), a gasification reactor ( 2 ) with cooled reaction space contour, a quench cooler ( 3 ) for partial cooling of the raw gas, a waste heat boiler ( 4 ), a scrubber ( 5 ) and a partial capacitor ( 6 ), whereby raw gas scrubbers ( 5 ) and partial capacitor ( 6 ) can be replaced or supplemented by a device for dry dust separation, which are connected in series, wherein, - a reactor ( 2 ) for the gasification of the supplied fuel dust with a free oxygen-containing oxidant, consisting of the delivery tube ( 1.1 ) for the fuel slurry and a line for the oxidant ( 2.1 ), which by means of burners ( 2.2 ) in the reaction space ( 2.3 ), which consists of a gas-tight welded, water-cooled pipes existing cooling screen ( 2.4 ) and a discharge device ( 2.5 ) in a quench cooler ( 3 ), - a quench cooler ( 3 ) without internals, in which nozzles ( 3.2 ) are arranged in one or more nozzle rings, via which the required water for partial quenching is injected, wherein the nozzles ( 3.2 ) are arranged flush with an inner shell, - a quench cooler ( 3 ) downstream waste heat boiler ( 4 ), - apparatus are connected downstream for the purification of the gas. Device according to claim 13, characterized in that the reaction space ( 3.2 ) of the quench cooler 3 directly with the waste heat boiler ( 4 ) is connected by pipes ( 4.1 ) the sensible heat of the raw gas is used to generate steam and in its lower part outlet openings for the raw gas ( 4.4 ) and for slag removal ( 4.3 ) with a water bath ( 4.2 ) are arranged. Device according to claims 13 and 14, characterized in that for cleaning a crude gas scrubber ( 5 ) and a scrubber ( 5 ) downstream partial condensation plant ( 6 ) are arranged. Device according to claim 15, characterized in that as Rohgaswäsche ( 5 ) a single or multi-stage Venturi scrubber is arranged. Device according to claims 13 and 14, characterized that for gas cleaning a mechanical dry dust collector is arranged. Device according to one of claims 13 to 17, characterized in that after water washing ( 5 ) and partial condenser or the mechanical dry dust separator further gas treatment stages such as a Rohgaskonvertierer or a desulfurization system are connected downstream. Device for carrying out a method according to claims 1 to 12, characterized by a system ( 1 ) for the production and supply of slurry, a gasification reactor ( 2 ) with cooled reaction space contour, a quench cooler ( 3 ) for partial cooling of the raw gas, a waste heat boiler ( 4 ), a scrubber ( 5 ) and a partial capacitor ( 6 ), whereby raw gas scrubbers ( 5 ) and partial capacitor ( 6 ) can be replaced or supplemented by a device for dry dust separation, which are connected in series, - a reactor ( 2 ) for the gasification of the supplied fuel dust ( 1 ) with a free oxygen-containing oxidant, consisting of the delivery tube ( 1.1 ) for the fuel slurry and a line for the oxidant ( 2.1 ), which by means of burners ( 2.2 ) in the reaction space ( 2.3 ), which consists of a gas-tight welded, water-cooled pipes existing cooling screen ( 2.4 ) and a discharge device ( 2.5 ) in a quench cooler ( 3 ), - a quench cooler ( 3 ) from which in the quenching room ( 3.1 ) partially cooled raw gas via the transfer line ( 3.4 ) to the waste heat boiler ( 4 ), - a waste heat boiler ( 4 ), which with Siederohren ( 4.1 ) and uses the sensible heat of the raw gas for steam generation, - a raw gas scrubber ( 5 ) and - a raw gas scrubber ( 5 ) downstream partial condensation plant ( 6 ), which may be replaced by a mechanical filtering dust deposit. Apparatus according to claim 19, characterized ge indicates that both in the quencher ( 3 ) as well as in the waste heat boiler ( 4 ) Water baths ( 4.2 ) and ( 4.5 ) are arranged, in which collects the cooled slag. Device according to claims 19 and 20, characterized in that both the quencher ( 3 ) as well as the waste heat boiler ( 4 ) Devices for discharging slag ( 4.3 . 4.6 ) are arranged.