AU2006201142A1

AU2006201142A1 - Method and device for high-capacity entrained flow gasifier

Info

Publication number: AU2006201142A1
Application number: AU2006201142A
Authority: AU
Inventors: Dietmar Adler; Joachim Lamp; Friedemann Mehlhose; Manfred Schingnitz
Original assignee: Future Energy GmbH
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2005-10-07
Filing date: 2006-03-20
Publication date: 2007-04-26
Anticipated expiration: 2026-03-20
Also published as: ZA200607404B; CN1944593B; CA2534407A1; DE102006029595A1; AU2006201142B2; DE102005048488C5; DE202005021659U1; DE102005048488B4; CN1944593A; US20070079554A1; DE102006029595B4; DE102005048488A1

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): Future Energy GmbH Dr. Manfred Schingnitz Invention Title: METHOD AND DEVICE FOR HIGH-CAPACITY ENTRAINED FLOW

GASIFIER

The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 Method and device for high-capacity entrained flow gasifier TECHNICAL FIELD The present invention relates to a method for entrained flow gasification with very high capacity that can be used for supplying large-scale syntheses with synthesis gas.

BACKGROUND

The autothermic entrained flow gasification of solid, liquid, and gaseous fuels has been known in the technology of gas production for years. The ratio of fuel to gasification medium containing oxygen is chosen so that higher carbon compounds are completely cracked for reasons of synthesis gas quality into synthesis gas components such as CO and H 2 and the inorganic components are discharged as molten slag; see J. Carl, P. Fritz, NOELL-KONVERSIONSVERFAHREN, EF-Verlag fur Energie- und Umwelttechnik GmbH, 1996, p. 33 and p. 73.

According to various systems used in industry, gasification gas and molten slag can be discharged separately or together from the reaction chamber of the gasification device, as shown in DE 197 131 Al. Either systems with refractory linings or cooled systems are used for the internal confinement of the reaction S:P59914 3 chamber structure of the gasification system; see DE 4446 803 Al.

EP 0677 567 B1 and WO 96/17904 show a method in which the gasification chamber is confined by a refractory lining. This has the drawback that the refractory masonry is loosened by the liquid slag formed during gasification, which leads to rapid wear and high repair costs. This wear process increases with increasing ash content. Thus such gasification systems have a limited service life before replacing the lining. Also, the gasification temperature and the ash content of the fuel are limited; see C. Higman and M. van der Burgt, "Gasification", Verlag ELSEVIER, USA, 2003. A quenching or cooling system is also described, with which the hot gasification gas and the liquid slag are carried off together through a conduit that begins at the bottom of the reaction chamber, and are fed into a water bath. This joint discharge of gasification gas and slag can lead to plugging of the conduit and thus to limitation of availability.

DE 3534015 Al shows a method in which the gasification media, powdered fuel and oxidizing medium containing oxygen, are introduced into the reaction chamber symmetrically through multiple burners in such a way that the flames are mutually S: P59914 4 diverted. The gasification gas loaded with powdered dust flows upward and the slag flows downward into a slag-cooling system.

As a rule, there is a device above the gasification chamber for indirect cooling utilizing the waste heat. However, because of entrained liquid slag particles there is the danger of deposition and coating of heat exchanger surfaces, which hinders heat transfer and may lead to plugging of the pipe system and/or erosion. The danger of plugging is counteracted by taking away the hot crude gas with a circulated cooling gas.

Ch. Higmann and M. van der Burgt in "Gasification", page 124, Verlag Elsevier 2003, describe a method in which the hot gasification gas leaves the gasifier together with the liquid slag and directly enters a waste heat boiler positioned perpendicularly below it, in which the crude gas and the slag are cooled with utilization of the waste heat to produce steam.

The slag is collected in a water bath, while the cooled crude gas leaves the waste heat boiler from the side. A series of drawbacks detract from the advantage of waste heat recovery by this system. To be mentioned here in particular is the formation of deposits on the heat exchanger tubes, which lead to hindrance of heat transfer and to corrosion and erosion, and thus to lack of availability.

S: P59914 5 CN 200 4200 200 7.1 describes a "Solid Pulverized Fuel Gasifier", in which the powdered coal is fed in pneumatically and gasification gas and liquefied slag are introduced into a water bath through a central pipe for further cooling. This central discharge in the central pipe mentioned is susceptible to plugging that interferes with the overall operation, and reduces the availability of the entire system.

The capacity of the various gasification technologies mentioned is limited to about 500 MW, which is attributable in particular to the fuel infeed to the gasification reactor.

SUMMARY OF THE INVENTION In a first aspect the present invention provides a method for the gasification of pulverized fuels that exist from solid fuels such as bituminous coals, lignite coals, and their cokes, petroleum cokes, coke from peat or biomass, in entrained flow, with an oxidizing medium containing free oxygen, by partial oxidation at pressures between atmospheric pressure and 80 bar, and at temperatures between 1,200 and 1,900 OC, at high reactor capacities between 1,000 and 1,500 MW, consisting of the component technologies: metering of the fuel, gasification reaction in a gasification reactor with cooled reaction chamber S P59914 contour, quench-cooling, crude gas scrubbing, and partial condensation, wherein a fuel, preferably a pulverized fuel, with a water content 10 wt.% and a grain size 200 gm, is supplied to multiple identically engaged metering systems that feed the fuel, preferably the pulverized fuel, through transport pipes to multiple gasification burners located at the head of a reactor, which are symmetrically arranged and contain additional oxygen infeeds, multiple dust burners with oxygen infeed are ignited in the head of the gasification reactor by ignition and pilot burners, the quantities of the pulverized fuel and oxygen fed to the dust burners are determined, with the overall total of all amounts of pulverized fuel and oxygen supplied being determined, and with a regulating mechanism assuring that the oxygen ratio neither exceeds nor falls below a ratio of 0.35 to 0.65, regardless of the distribution of pulverized fuel and oxygen to the burners, S: P59914 7 the pulverized fuel is converted in the gasification reactor at temperatures between 1,200 and 1,900 OC and at pressures between atmospheric pressure and 80 bar, into a crude synthesis gas and slag, the hot crude gas at 1,200 to 1,900 OC and the slag are cooled together down to the condensation point at temperatures between 180 °C and 240 OC in a quenching cooler by injecting water, the cooled crude gas is fed to further treatment stages such as water scrubbing, partial condensation, or catalytic processes.

The invention enables the conversion of fuels refined into pulverized fuel, such as ligniteand bituminous coals, petroleum coke, solid grindable refuse, and solid-liquid suspensions, socalled slurries, into synthesis gas. The fuel is reacted at temperatures between 1,200 and 1,900 °C with a gasification medium containing free oxygen, at pressures up to 80 bar, by partial oxidation to gases containing CO and H 2 This is done in a gasification reactor that is distinguished by a multipleburner system and by a cooled gasification chamber.

S P59914 8 The gasification method for the gasification of solid fuels containing ash at very high capacities with an oxidizing medium containing oxygen can be based on an entrained flow reactor whose reaction chamber contour may be confined by a cooling system, with the pressure in the cooling system being kept higher than the pressure in the reaction chamber. In one embodiment the process for preparing the fuel and feeding it to the gasification burners may be as follows: with dry pneumatic infeed by the dense-flow transport principle, the fuel is dried, pulverized to a grain size of 200 gm, and passed through operational bunkers to pressurized sluices, in which the dustlike fuel is brought to the desired gasification pressure by introducing a non-condensing gas such as N 2 or CO 2 Different fuels can be used here at the same time. By a system of multiple such pressurized sluices, they can be loaded and pressurized alternately. The dust under pressure then can then be sent to metering tanks, in the bottom of which a very dense fluidized bed is produced by likewise introducing a non-condensing gas, with one or more transport pipes immersed in the bed and opening into the burners of the gasification reactor. A separate infeed and metering system is associated with each high-capacity burner. The fluidized fuel dust can be caused to flow to the burners by applying a pressure differential between the metering tanks and the burners of the gasification reactor. The amount of S:P59914 9flowing fuel dust can be measured, regulated, and monitored by measurement devices and monitors.

With the proposed reactor, there may be the ability to pulverize the undried fuel likewise to a grain size of 200 pm and to mix the pulverized fuel with water or oil and to feed it as a slurry to the burners of the gasification reactor. The method of infeed, which is not described at this point, is configured by one skilled in the art according to the means known to him.

An oxidizing medium containing free oxygen may be supplied to the burners at the same time, and the slurry can be converted to crude synthesis gas by partial oxidation. The gasification may take place at temperatures between 1,200 and 1,900 oC and at pressures up to 80 bar. The reactor may have a cooled reaction chamber contour that is made up of a cooling shield. This can consist of a tubular shield welded gas-tight that is studded and lined with a material that is a good heat conductor.

The crude gas produced in the gasification reactor may leave the gasification reactor together with the liquid slag formed from the fuel ash and can be sent to a chamber located perpendicularly below it, in which the hot crude gas and the liquid slag are cooled by injecting water. The gas can be cooled S: P59914 10 completely down to the condensation point of the gas by spraying in excess water. The temperature is then between 180 and 240 oC, depending on the pressure. In one embodiment, a limited amount of cooling water can be fed in to cool the crude gas and slag by partial cooling to 700 to 1,100 oC, for example, and then to utilize the sensible heat of the crude gas to produce steam in a waste heat boiler. Partial quenching or partial cooling may prevent or sharply reduces the risk of slag caking on the tubes of the waste heat boiler. The water or recycled gas condensate needed for complete or partial cooling can be supplied through nozzles that are located directly on the jacket of the cooling chamber. The cooled slag can then be collected in a water bath and is discharged from the process. The crude gas cooled to temperatures between 200 and 300 oC may then sent to a crude gas scrubber, which is suitably a Venturi scrubber.

The entrained dust can then be removed down to a particle size of about 20 gm. This degree of purity may be inadequate for carrying out subsequent catalytic processes, for example crude gas conversion. It also has to be considered that salt mists can also be entrained in the crude gas, which have detached from the powdered fuel during gasification and are carried off with the crude gas. To remove both the fines 20 gm and the salt mists, the scrubbed crude gas can be fed to a condensation step in S:P59914 11 which the crude gas may be chilled indirectly by 5 to 10 OC.

Water can then be condensed from the crude gas saturated with steam, which may take up the described fine dust and salt particles. The condensed water containing the dust and salt particles can be separated from the crude gas in a following separator. The crude gas purified in this way can then be fed directly, for example, to a desulfurization system.

It would be advantageous if at least some embodiments of the present invention provided a gasification method that permits maximum capacities of 1,000 to 1,500 MW with reliable and safe operation.

BRIEF DESCRIPTION OF THE DRAWINGS The Figures show: Fig. 1: Shows a block diagram of one embodiment of the technology Fig. 2: Shows an embodiment of a metering system for pulverized fuel Fig. 3: Shows an embodiment of a device for feeding pulverized fuel for high-capacity generators Fig. 4: Shows an embodiment of a gasification reactor with full quenching S:P59914 12 Fig. 5: Shows an embodiment of a gasification reactor with partial quenching DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION Notwithstanding any other forms which may fall within its scope, preferred forms of the invention will now be described, by way of example only with reference to the accompanying drawings in which: Referring to the drawings Figure 1 is a block diagram showing the process steps of pneumatic metering of pulverized fuel, gasification in a gasification reactor with cooled reaction chamber structure 2, quench-cooling 3, crude gas scrubbing 4, in which there can be a waste heat boiler 4.1 between the quenchcooling 3 and the crude gas scrubbing 4, and a condensation or partial condensation 5 follows the crude gas scrubber 4.

Figure 2 shows a metering system for pulverized fuel consisting of a bunker 1.1 followed by two pressurized sluices 1.2, into which lead lines 1.6 for inert gas, and at the top of which depressurization lines 1.7 exit, with lines to the metering tank 1.3 leaving the pressurized sluices 1.2 from the bottom. There are fittings on the pressurized sluices 1.2 for monitoring and regulating. A line 1.5 for fluidizing gas leads into the metering tank from below, which provides for fluidizing the gas, S :P59914 13 and the fluidized pulverized fuel is fed through the transport line 1.4 to a gasification reactor 2.

Figure 3 shows another design of the device for feeding pulverized fuel for high-capacity generators 2, wherein a bunker 1.1 has three discharges for pulverized fuel, each leading to pressurized sluices 1.2, with each of the three pressurized sluices transporting pulverized fuel streams to one of three metering tanks 1.3, from which transport lines 1.3 lead to the dust burners 1.2 with oxygen infeed of the reactor. There are three dust burners 2.1 on each reactor 2 with oxygen feed, with an ignition and pilot burner 2.2 to start the reaction. Because of such intensive fluidized fuel flows and the presence of three burners 2.1, it is possible to achieve maximum capacities of 1,000 to 1,500 megawatts with reliable and safe operation.

Figure 4 shows a gasification reactor 2 with full quenching 3, with the ignition and pilot burner 2.2 and the dust burners 2.1, through which the fluidizing gas or a slurry of fuel and liquid is fed into the reactor, being positioned in the center of the head of the reactor 2. The reactor has a gasification chamber 2.3 with a cooling shield 2.4 whose outlet opening 2.5 leads to the quench-cooler 3, whose quenching chamber 3.1 has quenching nozzles 3.2, 3.3, and a crude gas discharge 3.4, through which S P59914 14 the finished crude gas can leave the quench-cooler 3. The slag that leaves the quench-cooler through an outlet opening 3.6 is cooled in the water bath Figure 5 shows a gasification reactor 2 with partial quenching, with the gasification reactor located in the upper part, in which dust burners 2.1 gasify the dust from the transport line 1.4, and with an ignition and pilot burner 2.2 positioned in the center. The gasification reactor 2 has a bottom opening into the quenching chamber 3.1, into both sides of which lead quenching nozzles 3.2, with waste heat boilers 4.1 placed below this.

The function will be described with a first example with reference to material flows and procedural processes: 240 Mg/h of pulverized coal is fed to a gasification reactor with a gross capacity of 1500 MW. This pulverized fuel prepared by drying and grinding crude bituminous coal has a moisture content of 5.8 an ash content of 13 and a calorific value of 24,700 kJ/kg. The gasification takes place at 1,550 °C, and the amount of oxygen needed is 208,000 m 3 i. The crude coal is first fed to a state-of-the-art drying and grinding system in which the water content is reduced to 1.8 The grain size range of the pulverized fuel produced from the crude S: P59914 15 coal is between 0 and 200 gm. The ground pulverized fuel (Fig.

1) is then fed to the metering system, the functional principle of which is shown in Fig. 2. The metering system consists of three identical units, as shown in Fig. 3, with each unit supplying 1/3 of the total amount of powder, or 80 Mg/h, each to a dust burner. The three dust burners assigned to them are at the head of the gasification reactor, whose principle is shown in Fig. 4. The usable pulverized fuel according to Fig. 2, which shows one unit of the powder metering system, goes from the operational bunker 1.1 to alternately operated pressurized sluices 1.2. There are 3 pressurized sluices in each unit.

Pressurized suspension to the gasification pressure is performed with an inert gas such as nitrogen, for example, which is fed in through the line 1.6. After suspension, the pressurized pulverized fuel is fed to the metering tank 1.3. The pressurized sluices 1.2 are depressurized through the line 1.7 and can be refilled with pulverized fuel. The 3 mentioned pressurized sluices in each unit are loaded alternately, emptied into the metering tank, and depressurized. This process then begins anew.

A dense fluidized bed is produced in the bottom of the metering tank 1.3 by feeding in a dry inert gas through the line likewise nitrogen, for example, that serves as the transport gas; 3 dust-transport lines 1.4 are immersed in the fluidized bed. The amount of pulverized fuel flowing in the transport S :P59914 16 lines 1.4 is measured and regulated in relation to the gasification oxygen. The gasification reactor 2 is shown and further explained in Fig. 3. The transport density is 250-420 kg/m 3 The gasification reactor 2 is shown and further explained in Fig. 3. The pulverized fuel (Fig. 3) flowing through the transport lines 1.4 to the gasification reactor 2 is discharged into 3 metering systems, each with a capacity of 80 Mg/h. The total of 9 transport lines 1.4 lead in groups of three each to 3 gasification burners 4.1 located at the head of the reactor 2.

At the same time, 1/3 of the total amount of oxygen of 208,000 m 3 NTP/h is fed to each gasification burner. The dust burners are arranged symmetrically at angles of 1200, and in the center there is an ignition and pilot burner that heats the gasification reactor 2 and serves to ignite the dust burner 4.1.

The gasification reaction, or the partial oxidation at temperatures of 1,550 takes place in the gasification chamber 2.3, which is distinguished by a cooled reaction chamber contour 2.4. The monitored and measured amount of pulverized fuel is subjected to ratio regulation with the supplied oxygen, which provides that the ratio of oxygen to fuel neither exceeds nor falls below a range of X 0.35 to 0.65. The value of X represents the ratio of the needed amount of oxygen for the desired partial oxidation to the amount of oxygen that would be necessary for complete combustion of the fuel used. The amount S :P59914 17 of crude gas formed is 463,000 m 3 NTP/h and is distinguished by the following analysis:

H

2 19.8 vol.% CO 70.3 vol.%

CO

2 5.8 vol.%

N

2 3.8 vol.%

NH

3 0.03 vol.% HCN 0.003 vol.% COS 0.04 vol.%

H

2 S 0.4 vol.% The hot crude gas at 1,550 OC leaves the gasification chamber 2.3 together with the liquid slag through the discharge 2.5 and is cooled to 212 oC in the quenching chamber 3.1 by injecting water through the rows of nozzles 3.2 and 3.3, and is then sent through the outlet 3.4 to the crude gas scrubber 4, which serves as a water scrubber to remove dust. The cooled slag is collected in a water bath 3.5 and is discharged downward. The crude gas washed with water after the water scrubber 4 is sent for partial condensation 5 to remove fines 20 pm in size and salt mists not separated in the water scrubber 4. For this purpose, the crude gas is cooled by about 5 OC, with the salt particles dissolving in the condensed water droplets. The purified crude S:P59914 18 gas saturated with steam can then be fed directly to a catalytic crude gas converter or to other treatment stages.

According to Example 2, the process of pulverized fuel feed is to occur according to Fig. 2 and Fig. 3, and the actual gasification in the same way as in Example 1. The hot crude gas and the hot liquid slag likewise pass through the discharge into a quenching chamber 3.1, in which the crude gas is cooled to temperatures of 700 1,100 OC, not with excess water, but only by spraying in a limited amount of water through nozzle rings 3.2, and are then sent to the waste heat boiler 4.1 to utilize the sensible heat of the crude gas to produce steam (Fig. The temperature of the partially cooled crude gas is chosen so that the slag particles entrained by it are.cooled in such a way as to prevent deposition on the heat exchanger tubes.

As in Example 1, the crude gas cooled to about 200 OC is then fed to the water scrubber and partial condensation.

S: P59914 19 List of reference symbols used 1. Pneumatic metering systems for pulverized fuel 1.1 Bunker 1.2 Pressurized sluice 1.3 Metering tank 1.4 Transport line Line for fluidizing gas.

1.6 Line for inert gas into 1.2 1.7 Depressurization line from 1.2 2. Gasification reactor with cooled reaction chamber structure 2.1 Dust burner with oxygen infeed 2.2 Ignition and pilot burner 2.3 Gasification chamber 2.4 Cooling shield Discharge opening 3 Quenching cooler 3.1 Quenching chamber 3.2 Quenching nozzles 3.3 Quenching nozzles 3.4 Crude gas outlet Water bath with slag S: P59914 20 3.6 Bottom discharge from 3 3.7 Lining 4 Crude gas scrubber 4.1 Waste heat boiler Condensation, partial condensation S:P59914

Claims

1. Method for the gasification of pulverized fuels that exist from solid fuels such as bituminous coals, lignite coals, and their cokes, petroleum cokes, coke from peat or biomass, in entrained flow, with an oxidizing medium containing free oxygen, by partial oxidation at pressures between atmospheric pressure and 80 bar, and at temperatures between 1,200 and 1,900 OC, at high reactor capacities between 1,000 and 1,500 MW, consisting of the component technologies: metering of the fuel, gasification reaction in a gasification reactor with cooled reaction chamber contour, quench-cooling, crude gas scrubbing, and partial condensation, wherein a fuel, preferably a pulverized fuel, with a water content 10 wt.% and a grain size 200 gm, is supplied to multiple identically engaged metering systems that feed the fuel, preferably the pulverized fuel, through transport pipes to multiple gasification burner located at the head of a reactor, which are symmetrically arranged and contain additional oxygen infeeds, S:P59914 22 multiple dust burners with oxygen infeed are ignited in the head of the gasification reactor by ignition and pilot burners, the quantities of the pulverized fuel and oxygen fed to the dust burners are determined, with the overall total of all amounts of pulverized fuel and oxygen supplied being determined, and with a regulating mechanism assuring that the oxygen ratio neither exceeds nor falls below a ratio of 0.35 to 0.65, regardless of the distribution of pulverized fuel and oxygen to the burners, the pulverized fuel is converted in the gasification reactor at temperatures between 1,200 and 1,900 OC and at pressures between atmospheric pressure and 80 bar, into a crude synthesis gas and slag, the hot crude gas at 1,200 to 1,900 OC and the slag are cooled together down to the condensation point at temperatures between 180 OC and 240 OC in a quenching cooler by injecting water, S :P59914 23 the cooled crude gas is fed to further treatment stages such as water scrubbing, partial condensation, or catalytic processes.

2. Method pursuant to Claim i, characterized in that three metering systems conduct fluidized pulverized fuel streams through transport pipes to three dust burners.

3. Method pursuant to Claim 1 and 2, characterized in that the grain size of the pulverized fuel is 100 gm.

4. Method pursuant to Claims 1 and 2, characterized in that the water content of the pulverized fuel is 2 wt.%. Method pursuant to Claims 1 to 4, characterized in that the pulverized fuel is fed in as a pulverized fuel-in-water slurry, with each burner having its own infeed system.

6. Method pursuant to Claims 1 to 4, characterized in that the pulverized fuel is fed to the gasification reactor as a pulverized fuel-in-oil slurry, with each of the burners having its own infeed system. S :P59914 24

7. Method pursuant to Claims 1 to 4, characterized in that one or more fuels can be gasified at the same time.

8. Method pursuant to Claims 1 to 7, characterized in that a different fuel is gasified by each gasification burner.

9. Method pursuant to Claims 1 to 8, characterized in that pulverized fuels fed through the gasification burners pneumatically or as a slurry are gasified. Method pursuant to Claims 1 to 9, characterized in that partial cooling to temperatures between 700 and 1,100 OC and waste heat recovery by steam generation from the sensible heat of the crude gas follow the gasification reactor.

11. Device for implementing a method pursuant to Claims 1 to characterized by the fact that multiple, preferably three, streams of pulverized fuel pass from a bunker to pressurized sluices that conduct the streams of pulverized fuel to metering tanks, from which multiple, preferably three, transport S:P59914 25 lines lead to multiple, preferably three, dust burners in a gasification reactor, a high-capacity reactor with multiple, preferably three, gasification burners and an ignition and pilot burner symmetrically arranged at its head, a system at the gasification burners to measure and regulate the amounts of pulverized fuel and oxygen flowing in, with integral monitoring and regulation of the overall total amounts of pulverized fuel and oxygen flowing to the gasification reactor, a quenching chamber to cool the crude gas produced in the reactor and the slag, followed by combination with a crude gas scrubber and a cooler for performing a partial condensation.

12. Device for implementing a method pursuant to Claims 1 to characterized by a high-capacity reactor with 3 gasification burners and an ignition and pilot burner at its head, S:P59914 26 arrangement of a system to measure and regulate the amounts of pulverized fuel and oxygen flowing into the gasification burners with integral monitoring and regulation of the overall total amounts of pulverized fuel and oxygen flowing to the gasification reactor. arrangement of a quenching chamber for the partial cooling of the crude gas produced in the reactor and of the slag, followed by combination with a waste heat boiler to recover steam with further cooling of crude gas and slag, followed by a water scrubber and partial condensation.

13. Device pursuant to Claim 11 or 12, characterized in that each gasification burner has its own associated metering system.

14. A method for the gasification of pulverized fuels substantially as herein described with reference to the accompanying drawings and examples. Dated this 20th day of March 2006 FUTURE ENERGY GMBH DR MANFRED SCHINGNITZ By its Patent Attorneys GRIFFITH HACK S:P59914