Method of fuel supply for fluidised gasification reactor from storage hopper

FIELD: oil and gas industry.

SUBSTANCE: object of the invention lies in that the method of pressurised fuel delivery is suggested for gasification unit and this cost-effective method ensures minimisation or even complete removal of hazardous substances emission in the process of coal sluicing and transporting. It is attained due to the fact that for sluicing and transporting the gas containing at least 10 ppm of CO in its volume is used; at that oxygen-containing gas is mixed to the above gas and the mixture is heated up to the temperature when oxidation of at least 10% of hazardous substances in gas takes place.

EFFECT: increased efficiency of method.

7 cl, 3 dwg

The invention relates to a method of providing a reactor for gasification in a suspended stream of fuel from the hopper to the intermediate switching at least one gateway hopper and at least one receiving hopper in the gasification reactor in suspension stream is produced containing CO, H₂and fly ash gas.

In the patent EP 0333991 A1 describes a method of supplying pulverized coal from the hopper in a lock hopper in the gasifier gasification in a suspended thread, and in this case, for locking and transportation use synthesis gas, which is mixed with oxygen.

When locking and supplying the fuel in a state of fine-grained powder with containing carbon dioxide, carbon monoxide and oxygen gas, under high pressure gasifier gasification in a suspended thread in which fine-grained or powder (<0.5 mm) fuel, for example coal, petroleum coke, biological waste or combustible materials in a suspended state with a low content of particles (<50 kg/m³) reacts with oxygen-containing gasification agent under high pressure up to 10 MPa at a temperature above the melting temperature of the slag, oxygen-containing gas is supplied at a ratio below the stoichiometric t is to that produced containing carbon monoxide gas.

Since the first fuel is under ambient pressure, the pressure first through the delivery system to reach a residual pressure above the pressure in the generator, then to the right doses to bring to the burners of the gasification reactor under pressure.

The preferred method provides that the fuel from the hopper is fed into a lock hopper. In the bunker, you first create a pressure above the pressure in the reactor, and then the fuel through the supply pipe transporting dense flows in constantly under pressure hopper to the burners of the gasifier. From this hopper the burner always provided the metered fuel flow. Required to transport dense flow conveying gas is supplied near the exit from the lock hopper or into the transport pipeline. Then devastated the sluice bins removed the pressure to ensure that it is at approximately atmospheric pressure could take the next portion of the fuel. Opening when the pressure of the gas is cleaned from dust and emitted into the atmosphere.

For sluicing is commonly used nitrogen from the plant for separating air or carbon dioxide. Carbon dioxide is used in the case when producing synthesis gas and the hydrogen and/or WITH low nitrogen content.

Carbon dioxide can be obtained in the process gas after gasification. Often emerging from the gas generator, the gas is freed from dust and cleaned and subjected to a conversion process FROM order to establish necessary for the synthesis ratio of N₂/WITH or to obtain pure hydrogen. WITH water and turn into CO₂and hydrogen. After that, the gas cools, the moisture condenses and finally CO₂washed in the washing installation with recirculating solvent, such as methyldiethanolamine, solvent Genosorb or methanol. In desorber CO₂is released from the solution as a result of decreasing pressure and increasing temperature. Thus obtained gas along with CO₂contains also other components, such as H₂WITH N₂, methane, hydrogen sulfide, argon, pair of used solvents, such as methanol, etc. the Content is, for example, of 0.1%. Although you may further reduce the content of harmful substances in the washing machine, but the costs (investment and operating costs, for example, the consumption of steam and electricity) increase rapidly with increasing purity requirements (production of gaseous products from the crude synthesis gas is described, for example, in DE 10 2007 008 690 A1). Particularly difficult is the removal of the OST is tcov WITH from the flow of CO ₂.

In DE 10 2007 020 333 A1 describes a method of operating a system boot dust for coal gasification under pressure, which consists of hopper, gateways to download dust and dosing tank. In the bunker as a means to create an inert atmosphere and loosening is fed to the heated nitrogen, while creating pressure in shluzova hopper and transport of dust are carried out using pure CO₂. Coming from the lock hopper when the pressure of the gas is subjected to reduced pressure and then released in the filter from the solids. While unloading airlock hopper in a dosing tank is under the influence of gravity.

In DE 36 90 569 C2 describes a method of removing sulfur containing compounds from the residual gas.

The disadvantages of the known solutions are, in particular, that used for sluicing and the fluidization gas should contain only low concentrations of environmentally harmful substances WITH H₂S, methanol and the like, as it is discharged into the atmosphere. Based on the gravity of the locking located one above the other bunkers require a significant investment from a great height and was not sufficiently reliable in operation due to compaction of the granular material. Despite the many different designs, Okaz the moose is very difficult to carry out the process of increasing the pressure so gently, to maintain a sufficiently low level of internal stresses in the bulk material.

The objective of the invention is to provide a method of fuel supply installation of gasification under pressure, which economically provides that the release of harmful substances in the process of sluicing coal and its transportation will be minimized or completely eliminated.

In the case described at the beginning of the type of method, this task is solved according to the invention due to the fact that for locking and/or transportation is used, a gas containing not less than 10 parts per million by volume (preferably from 100 to 1000 parts per million), however, this gas is mixed gas containing less than 5% oxygen, and that this gas mixture is heated to a temperature at which the oxidation of at least 10% contained in the gas of carbon monoxide.

It turned out that, despite the high concentration gas CO, H₂S and vapors used in the processing of gases solvents such as methanol and the like, with the invention of the allocation of these harmful substances in the process of locking and transportation of coal can be significantly reduced or the selection can even be completely prevented.

In the method of performing the invention provides that are used for sluicing kislorodnije is ASCII gas is used for loosening the fuel storage hopper and/or for loosening and fluidization content sluice bins, and/or for further transportation from the lock hopper, and/or for loosening and fluidization in the receiving hopper for moving fuel between the parts of the installation from the hopper and/or the gasification reactor in suspension flow.

A particular advantage of this invention lies in the fact that everything used in connection with the locking and supply of fuel to the gasification reactor in suspension flow gases can satisfy the required criteria.

It may be preferable if, as is also provided in the invention, containing a harmful substance (CO) and oxygen gas mixture is directed through at least one catalyst to accelerate the oxidation of carbon monoxide.

Depending on the purpose of use and design the appropriate installation can be according to the invention are also provided, which is used to increase the pressure in shluzova the sluice hopper or hoppers gas is subjected to catalytic oxidation, and gas for transportation fuel catalytic oxidation is not exposed.

In yet another embodiment, the invention provides that the opening when the pressure of the hopper gas is supplied to the pressure stage of the compressor and/or compressor installation to Shluzovaya bunker or gateway bunkers.

Dalnas the e benefits details and distinctive features follow from the following description and from the figures:

Figure 1 - block diagram of the supply of fuel to the gasification reactor,

Figure 2 is similar in purpose setting with multiple receiving bins,

Figure 3 - installation essentially according to figure 1 with a modified inlet used in and generated gas flows.

First, it should be noted that the figures are all the same in function to the elements and line flows have the same reference designations, first of all, if the corresponding functions in separate installations are identical or similar.

On the setup diagram according to figure 1 figure 1 shows the fuel in the hopper 2, this shows a more bold line path of the fuel leads from the hopper 2 into a lock hopper 3, thence through line 4b into a hopper 5, and thence through conduit 6A to 6 burners of the gasification reactor 7.

Coming when filling the lock hopper gas through a pipeline 3E is applied to the filter 10, after filtering the gas through the pipeline 10th released into the environment or reserved for future use. The dust from the filter is returned to hopper 2. Displaced when filling hopper 2 gas through a pipeline 2E is supplied to the filter 10.

Of gas the generator with gas in the flow of slag and containing solids water are removed through 7b gas pipeline 7a goes to the 8 processing gas, the synthesis gas is removed from the installation of 8 processing gas by pipeline 8A.

The resulting carbon dioxide can be, as shown in figure 1, is divided into two streams fed into the compressor flow 8b and applied to the pipeline 8C for gas export. To the thread 8b according to the invention through the pipeline 16 to the compressor 18 or pipeline 16A after the compressor is mixed with oxygen-containing gas, e.g. air, the stream is cooled in the heat exchanger 19 through line 18b or 3A is returned in a closed loop in a lock hopper to create the pressure.

The principle of operation according to figure 1 is as follows:

Powdered fuel 1 previously accumulated in the accumulating hopper and from there through the connecting pipe is passed to a lock hopper 3. In order to be able to pick up the fuel from the hopper, the sluice bins 3 must first be lowered pressure. Coming out of the sluice bins gas 3E cleaned from the dust in the filter 10 and is discharged into the atmosphere. Then lock the bins are filled with fuel, and using gases 3A and 3b creates increased pressure. Then the output gateway pipeline bunker blown gas 3C and powdered fuel from the lock hopper 3 through line 4b gives the I into a hopper 5. The pipeline serves the gas 3b for fluidization and transport gas 4A.

A hopper 5 is constantly under work pressure and continuously supplies fuel to the gas generator 7 via several pipelines 6A. The feed from the hopper is carried out by gas supply 5b for loosening and fluidization in the exit area of the bunker and with additional transport gas 5C. The flow of fuel 6A is transported continuously and manageable way to transport dense flow in the gas generator 7 through the burner 6.

Opening when the pressure of the hopper gas 5e is returned to a suitable degree of pressure compressor 18, in order to reduce the required amount of gas 8b and reduce the capacity of the compressor. The gas generator 7 includes a gasification reactor, the cooling unit and gas cleaning from dust and cooling unit and output discharge through the gateway of slag and 7b containing solids water.

Installation 8 gas treatment portion of the carbon monoxide and water vapor turns into carbon dioxide and hydrogen. In addition, the gas is cleaned with a solvent (for example, methyldiethanolamine or methanol), and carbon dioxide is separated from the synthesis gas 8A (mainly H₂and WITH). Received in the installation of the purification of gas containing carbon dioxide gas has a low pressure is s and contains, typically, a small amount of harmful substances, such as, for example, carbon monoxide <1%, hydrogen sulfide <10 parts per million by volume, traces of hydrocarbons, etc.

The resulting carbon dioxide may have a different level of quality. Figure 1 shows two stream CO₂8b for compression and 8C for export. The exported flow can often contain CO, H₂S and methanol, for example, when the gas is used to displace crude oil under the earth's surface. If this gas content of harmful substances must be reduced, this can also be accomplished by oxidation, as shown in figure 1.

To the crude stream CO₂mixed oxygen-containing gas 16C, preferably air, and the temperature of the mixture in the heat exchangers 22 and 23 is increased in order to catalytically oxidize in the reactor, preferably, the harmful substances. After cooling in a heat exchanger containing small quantities of hazardous substances gas 22A may be vented to the atmosphere or used in the future.

Stream 8b is compressed in the compressor 18 and is used for sluicing, fluidization and pneumatic transport fuel in the gasifier. Part of this gas is discharged into the environment; as shown in the figure 1 example, this is the 10th thread.

In order to reduce the emission of harmful substances, containing the Reden substances gas 8b oxygen-containing mixed gas 16 and the mixture is compressed adiabatically or polytrope with only minor intermediate cooling.

Alternatively, the addition of oxygen, the flow 16A, may occur after the compressor 18. Compressed hot gas can be heated by means of heat exchangers (not shown), and to stay some time at this temperature for hazardous substances, primarily CO and methanol, were able to react with contained in the gas mixture with oxygen. Although high temperature gateway gas and transport gas is thermodynamically rational, it is, however, complicates the distribution of gases and causes the release of gases from the fuel particles, which can lead to additional emission of harmful substances. Therefore, the gas is cooled to the desired temperature in the heat exchanger 19, for example the evaporator.

Adulteration of oxygen 16 to the compressor 18 is advantageous from the point of view of the operation of the gas generator. Usual environment for gasification fuel 6A and oxygen are fed into the gasifier through a separate concentric channels of the burner and the first form in the gas generator of the individual jets, which are gradually mixed.

The reaction rate of oxygen with the hot gas in the gas generator by several orders of magnitude higher than with the first relatively cold fuel, so the majority of the oxygen reacts with the gas, resulting in the formation of extremely hot gas flame and a relatively long cool article the AP fuel. Only as a result of mixing under the action of radiation temperature of the fuel rises, so what can happen gasification of fuel.

If part of the oxygen is supplied together with the fuel, in the immediate vicinity of fuel particles flowing exothermic reaction with oxygen, making cold jet fuel and, thereby, the flame becomes shorter. The practical consequence is a higher degree of conversion of the fuel and higher performance of gasification, since the maximum rate of fuel supply to the burner of the gas generator is limited by the length of the flame.

Figure 2 shows in more detail an alternative embodiment of the locking systems and transportation fuel with reduced emissions of harmful substances, in this case, as mentioned above, the same function parts of the installation have the same reference designations as in figure 1.

Powdered fuel 1 previously accumulated in the storage hopper 2 and from there through the connecting lines is transmitted in three sluice hopper 3. Pipelines before opening the sluice gates blown gas 2C. During the process of filling sluice bins in the discharge cones hopper gas 2b for fluidization. Lock hoppers are used for fuel with the time shift, so it's quasi-continuous supply of bunkers 5.

Filled with fuel sluice bins using gases 3A and 3b creates increased pressure. Then the fuel is moved into the receiving hopper 5, and the gas 3b for fluidization is served in the discharge cone, and the transport of gas through pipelines 3C and 4A. Then the pressure in the devastated hoppers is discharged through line 3E. Opening when the pressure of the gas 3E is heated, for example, in heat exchanger 11, to avoid freezing and condensation while reducing the pressure in the filter 10. Gases may be partially collected in the buffer tank 9 and further used, for example, in the storage hopper, the threads 2A, 2b, 2C and to create an inert atmosphere in the mill. At least one part of the gas is freed from dust in the filter 10 and is discharged into the atmosphere. Buffer tank 9 is additionally supplied with gas 9a, for example, during the start-up phase of the installation. The part is listed together with the fuel into the receiving hopper 5 transport gas is discharged through a pipeline 5e.

The pressure coming out at lower pressure gas 5e enhanced with the help of the device to increase pressure, such as injector, which is driven by a working gas 18d, so that the gases can be returned to the lock hoppers or used the AK transport the gas.

Separated in the installation of 8 processing gas containing mainly CO₂cold gas 8b is compressed using a compressor with cooling between stages to reduce the power consumption of the compression power. Part of the compressed gas, for example, with parameters 60 bar and 100°C, accumulated in the buffer tank 17 in which the control pressure is maintained at a constant pressure, and then is introduced into the system of transportation of fuel between the discharge cones sluice bins and the gas generator.

Since a large part supplied in the system of transportation of fuel supplied to the gas generator and only a small part in the environment, it is often possible to agree with the presence of harmful substances and WITH methanol, etc. in threads 3b, 3C, 4A, 5A, 5b, 5C. On the contrary, to be used for sluicing stream 18b gas mixed with oxygen-containing gas.

In order to accelerate the oxidation of harmful substances, the mixture may be heated, for example, in the heat exchanger 15 type gas/gas and further heated in the heater 14 is heated using an external heat Q, and brought into contact with the catalyst 13. Additionally, the gas is heated by the exothermic oxidation, so that the heat exchanger 14 at a sufficiently high content of measurable oxidation of substances H₂CO, H₂S, etc. can be and is solely. The gas is heated, for example, in the heat exchanger 15 to 190°C and heater 14 to 220°C. In a catalytic reactor 13, methanol, etc. turn into significantly less toxic gases.

Coming out of the reactor 13, the gas is cooled in the heat exchanger 15 to about 130°C and fed to the buffer tank 12. Using the flow regulator is set approximately constant average flow. Therefore, strong fluctuations in flow sluice bins do not affect the flow oscillations in the reactor 13.

Returned and compressed gas 20A may be an alternative used, for example, as a transport gas 4A and 5C, or as a gas for fluidization.

Optimal parameters of the oxidation of CO, methanol and the like, temperature, oxygen concentration, amount of catalyst or the residence time in the high temperature zone, if the catalyst is not used, should be determined by economic analysis. Because with the increase of oxygen concentration required time and amount of catalyst is reduced, you can expect optimum in excess oxygen. However, the high oxygen concentration in shluzova gas can cause fire and explosion mixed with powdered fuel, especially when using reactive fuels, such as lignite or biological is opleve. Therefore, the oxygen concentration should not be higher than 5%.

Figure 3 shows another option to reduce the emission of harmful substances according to the invention with three fractions of CO₂with different pressures. Thread 16 of the oxygen here is admixed to the fraction 8b with the lowest, for example approximately atmospheric pressure, the mixture is adiabatically compressed in the compressor 18 to the pressure of the second fraction 8C, for example 5 bar, whereupon the gas is heated to approximately 200°C and mixed with 8s.

If necessary, the mixture may be further heated at 22 and 23. Then, in 24 the oxidation of harmful substances and 22 heat recovery. Freed from most of the harmful substances low-pressure gas is used under low pressure zone 22A coal preparation other consumers 22b, when the locking and transportation at 22 ° C after pre-compression in the compressor NR high pressure, and the residue is subjected to reduced pressure in the expander 25 and is returned to mechanical or electrical energy.

Gas 25A low pressure can be used to create an inert atmosphere in an apparatus for grinding coal or emitted to the atmosphere. Other heat exchangers, such as heat flows 8C, 22d, 25A or cooling threads 18a, 18b and 22A to 22p, should be taken into account in accordance with the technical the x and economic aspects. Part received in the installation of 8 treatment, consisting mainly of CO₂gas 8d oxygen-containing gas is not mixed. This gas, if necessary, after compression, is exported and/or used in the exhaust from the gas generator flows, for example, in the installation of dust removal, installation of processing fly ash and as a purge gas and create a protective atmosphere to prevent loss of usable gas in the oxidation of H₂WITH.

When the pressure on shluzova hopper 3 gas due isentropically or polytropic expansion noticeably cooled, resulting in the formation of ice from water vapor, which comes from a residual moisture content of the coal, and the condensation of CO₂can interfere with the process. In addition, a lock hopper cyclically exposed to low temperatures, resulting in the wall of the hopper is a mechanical effect that under cyclic process leads to material fatigue. To prevent this, a lock hopper is heated externally by an electric heater or the environment is fluid. Other equipment 2, 4, 5, 9, 10 fuel for transportation and connecting piping must also be heated in order to prevent cooling below the dew point.

The figures shown for example preference is sustained fashion embodiments of the invention, in order to clearly show the path of harmful substances to the atmosphere and methods of reducing their emissions. The limitation of emissions into the atmosphere according to the invention is suitable to alternative embodiments of processes locking and transportation fuel, gasification and gas treatment, for example:

- after under the action of gravity from the sluice bins 3 into the receiving hopper 5;

without the use of a buffer tank 9 low pressure or more buffer tanks with different pressure;

several storage bins and/or several bunkers;

- gasification with recovery boiler, dry separation of dust and the use of inverse gas as a gas for cooling;

- gasification with cooling water and wet separation of dust;

- conversion of CO in the containing H₂S gas from a gas generator or first allocation of sulfur from the gas and then hydration and conversion FROM;

- supply of oxygen-containing gas to the compressor 18, after the compressor or after partial compression;

without heat exchanger 15 and the cooler gas, such as steam generator between 13 and 12;

from the installation process gas enters only one thread CO₂this stream is mixed with oxygen-containing gas and one part of the mixture is compressed and is oxidized at high pressure, and the other part of the rabatyvaetsya at low pressure;

from the installation process gas enters only one thread 8C CO₂this stream is mixed with oxygen-containing gas 16C, the mixture is heated with 22 and 23 and harmful substances catalytically oxidized and one part of the cooled gas 22A is directed into the compressor 18, and the remainder is exported.

Oxygen-containing gas 16 may have the same composition as the flow of oxygen to the gasifier. Usually for gasification are used are obtained by cryogenic method gas, which contains from 85 to 99.8% O₂up to 3% of Ar and nitrogen. However, it can also be used in air, oxygen-enriched air or nitrogen with oxygen, for example, 2%.

As consisting mainly of carbon dioxide gas 8b in plants gasification is obtained, as a rule, connected in series in an apparatus for washing gas, for initial start-up of the entire installation requires imported gas, such as CO₂or nitrogen. Often it is preferable to use nitrogen, which for this purpose may be stored in a liquid state. As soon as the work will move so that the purification of gas will be separated carbon dioxide for further normal operation will switch to the containing carbon dioxide gas.

Thread 18C shows that the compressed gas 18 with a low content of harmful the substances can be used for other purposes, for example, as a gas for sluicing and the purge gas in the processing of fly ash. Export gas medium pressure can be selected from the buffer tank 9, there is also the 10th thread under a slight excess pressure.

Shown in figure 2, the execution of the hopper 2, the gateway of the hopper 3 and the conveyor pipe 4b is an example, which is used here to demonstrate the principle of the process. Provided that the number of lock hoppers can be large. Provided also that the sluice bins provide via several transport pipelines receiving hopper 5.

REFERENCE DESIGNATION:

1 Fuel

2 hopper

3 Rotary hopper

4 Site Association

5 Receiving hopper

6 Burner

7 the gasification Reactor, the cooling unit and gas cleaning from dust

8 Installing gas purification

9 Gas buffer tank

10 Filter

11 gas Heater

12, 17 Buffer pressure tank

13, 24 Catalytic reactor

14, 23 gas Heater

15, 22 heat Exchanger gas-gas

16, 16A Oxygen-containing gas

18 Compressor

19 the gas Cooler

20 Injector or compressor

21 Site mixing of gases

2b, 3b, 5b Gas for loosening and fluidization

2C, 3C, 4A, 5C Additional transport gas

3A Gas for sluicing

5A Gas for pressure maintenance

8A Predominantly H₂and WITH or only H₂

8b, 8C Untreated CO₂

18a Gas for fluidization and transportation

18b Gas for sluicing

1. The way to ensure reactor (7) gasification in suspended fuel flow (1) of the hopper (2) with intermediate switching at least one gateway hopper (3) and at least one receiving hopper (5), while in the gasification reactor in suspension stream is produced containing CO, H₂and fly ash gas,
characterized in that
for locking and/or transportation is used containing at least 10 parts per million by volume WITH gas, while to this gas mix gas with oxygen content less than 5%, and that this gas mixture is heated to a temperature at which the oxidation of at least 10% contained in the gas of carbon monoxide.

2. The method according to claim 1, characterized in that is used for sluicing oxygen-containing gas is used for loosening the fuel storage hopper (2) and for loosening and fluidization of the content gateway bin (3), and for further transportation from the lock hopper (3), and for loosening and fluidization in the receiving hopper (5), for the evaluation of the Yes fuel between plant parts and from the hopper (5) and the reactor (7) gasification in a suspended thread.

3. The method according to claim 1, characterized in that the containing carbon monoxide and oxygen gas mixture is sent at least one catalyst to accelerate the oxidation of carbon monoxide.

4. The method according to claim 3, characterized in that is used to increase the pressure in shluzova hopper (3) or sluice bins (3) gas (3A) is subjected to catalytic oxidation, and gas for transportation fuel (4A, 5C) catalytic oxidation is not subjected to.

5. The method according to one of claims 1 to 4, characterized in that the opening when the pressure of the gas (5e) of the hopper (5) is led to the pressure stage of the compressor (18) and/or through the device for compression to Shluzovaya bunker or gateway bunkers.

6. The method according to one of claims 1 to 4, characterized in that at least 50% separated in the device processing gas containing carbon dioxide gas, admixed oxygen-containing gas.

7. The method according to claim 5, characterized in that at least 50% separated in the device processing gas containing carbon dioxide gas, admixed oxygen-containing gas.