RU2738120C1 - Apparatus for producing heated gases from carbon-containing material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to an apparatus for producing hydrogen, which can be used in fuel cells of hydrogen power engineering. Plant comprises a carbon conversion reactor, a calcium carbonate decomposition reactor CaCO₃, an iron oxide oxidation reactor FeO, a cyclone, a retort, a pyrolysis furnace, pyrolysis furnace burner, mulched wood loading gate, internal burner, external burner, blow fan, supercharger, superheater, coal unloading gate, air heater, prechamber, upper overflow, lower overflow, lower linear overflow, upper linear overflow, primary and secondary heat recovery devices for heating burner air due to heat of exhaust gases after decomposition reactor CaCO₃ and hydrogen, steam heater for steam water heating due to use of heat of furnace combustion products and computer control unit with which the gas analyzer, flow meters, thermometers, adjusting valves are connected electrically, as well as electric driving motors of coal-firing fan and supercharged air pump with possibility of changing their rotation frequency.

EFFECT: invention provides higher thermal efficiency of the installation.

1 cl, 1 dwg

Description

The invention relates to the field of construction of devices for producing hydrogen and related gaseous products by converting charcoal using water vapor. The unit can be used to obtain practically pure hydrogen for its subsequent use in fuel cells of hydrogen energy.

A known installation containing a technologically interconnected reactor for the conversion of carbon, a reactor for the decomposition of calcium carbonate CaCO ₃ , a reactor for oxidation of iron oxide FeO, a cyclone, a retort, a pyrolysis furnace, a pyrolysis furnace furnace, a wood loading gateway, an internal burner, an external burner, a blower, a blower compressed air, superheater, coal unloading gate, air heater, prechamber, upper crossflow, lower crossflow, lower linear crossflow, upper linear crossflow (see the description of the patent for invention of the Russian Federation No. 2615690). Disadvantages of the known device:

1. The heat of the outgoing heated furnace combustion products is not used to increase the thermal efficiency of the installation.

2. The heat of the removed heated hydrogen is not used to increase the thermal efficiency of the installation.

3. The heat of the removed hot air with a lack of oxygen is not used to increase the thermal efficiency of the installation.

These disadvantages are eliminated in the claimed invention, which is aimed at solving the problem of increasing the thermal efficiency of the installation.

The task is technically solved with the help of the proposed installation for producing heated gases from a carbon-containing material, containing a technologically interconnected carbon conversion reactor, a calcium carbonate decomposition reactor CaCO ₃ , an iron oxide FeO oxidation reactor, a cyclone, a retort, a pyrolysis furnace, a pyrolysis furnace furnace, a loading gateway wood, internal burner, external burner, blower fan, compressed air blower, steam superheater, coal unloading gate, air heater, prechamber, upper crossflow, lower crossflow, lower linear crossflow, upper linear crossflow, according to the invention, in an installation for obtaining heated gases from carbon-containing material additionally there are technologically interconnected computer control unit, primary and secondary heat exchangers for heating the burner air due to the heat of the exhaust gases after the reactor for the decomposition of calcium carbonate CaCO ₃ and hydrogen, there is steam heating a heater for heating water vapor due to the use of the heat of furnace combustion products, there are electrically connected to the computer control unit: a gas analyzer, a flow meter and a thermometer located on the exhaust pipe of the furnace combustion products, a control valve, a flow meter and a thermometer located on the pipe for removing pyrolysis gases, control valve, flow meter and thermometer located on the wet steam supply pipe, control valve, thermometer and flow meter located on the hydrogen outlet pipe, control valve located on the internal burner, thermometers for measuring the temperature of the medium inside the pyrolysis furnace, retort and oxide oxidation reactor iron FeO, a thermometer and a flow meter for measuring the temperature and flow rate of superheated water vapor, a thermometer and a flow meter for measuring the temperature and flow rate of compressed air, there is a technological electrical connection of the computer control unit with electric motors of the blower fan drives of the boiler and compressed air blower with the ability to change their speed.

The design of the inventive device is shown in Fig., Where the positions indicate the following elements and assemblies:

1 - carbon conversion reactor,

2 - reactor for the decomposition of calcium carbonate CaCO ₃

3 - reactor for oxidation of iron oxide FeO,

4 - a pipe of superheated steam,

5 - compressed air pipe,

6 - a pipe for removing hydrogen,

7 - a pipe for removing carbon dioxide,

8 - air exhaust pipe with a lack of oxygen,

9 - loading of calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ ,

10 - spent calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ ,

11 - spent calcium oxide CaO and ash,

12 - cyclone,

13 - retort,

14 - pyrolysis oven,

15 - loading wood,

16 - firebox of the pyrolysis furnace,

17 - timber loading gateway,

18 - pipe for removal of furnace combustion products,

19 - pipe for removal of pyrolysis gases,

20 - internal burner,

21 - external burner,

22 - blower fan,

23 - compressed air blower,

24 - atmospheric air,

25 - loading calcium oxide CaO,

26 - superheater,

27 - coal unloading gateway,

28 - air heater,

29 - wet steam supply pipe,

30 - wood particles,

31 - particles of charcoal,

32 - particles of calcium oxide CaO,

33 - particles of iron oxide FeO,

34 - particles of hematite Fe ₂ O ₃ ,

35 - particles of calcium carbonate CaCO ₃ ,

36 - prechamber,

37 - upper crossflow,

38 - bottom crossflow,

39 - bottom linear flow,

40 - upper linear crossflow,

41 - primary heat exchanger,

42 - computer control unit,

43 - steam heater,

44 - thermometer,

45 - fuel

46 - adjusting valve,

47 - flow meter,

48 - gas analyzer,

49 - burner air,

50 - secondary heat exchanger.

The arrows indicate the directions of the technological movement of the components and working media.

Dotted lines indicate electrical connections of the computer control unit 42 with thermometers 44, with electrically driven control valves 46, blower 22, compressed air blower 23, flow meters 47 and gas analyzer 48.

The purpose and interaction of elements and nodes is as follows.

The carbon conversion reactor 1 structurally represents a sealed heat-insulated container (thermal insulation is not conventionally shown in the figure), having mushroom-shaped nozzles at the bottom of the hearth, through which superheated water vapor is continuously blown through, supplied through pipe 4.

The carbon required for the conversion in the form of charcoal particles 31 with a size of up to 12 mm is produced directly as part of the installation in a retort 13 located inside the pyrolysis furnace 14 from wood particles 30 fed through a sealed lock 17.

In the reactor 1, heated particles of charcoal 31 are supplied from the retort 13 through the periodically opened coal discharge gate 27 and the inclined pre-chamber 36.

The gateway 27 is a large-sized electrically driven fire-resistant valve that blocks the access of wood particles 30 through an inclined prechamber 36 to reactor 1.

Superheated water vapor is obtained by supplying moist water vapor through the pipe 29 for superheating to the superheater 26, located in the retort 13 and in the firebox of the pyrolysis furnace 16.

Steam is superheated due to the heat of the wood pyrolysis process in the retort 13 and due to the heat of combustion of the emitted pyrolysis gas in the burner 20.

In the reactor 1 at a temperature of 800 ... 850 ° C in a fluidized fluidized bed, the interaction of carbon in the composition of charcoal particles 31 and superheated water vapor supplied through pipe 4 with the release of carbon dioxide CO ₂ and hydrogen H ₂ takes place:

C + 2H ₂ O = CO ₂ + 2H ₂ .

In reactor 1, the reaction of interaction of particles 32 of calcium oxide CaO with the resulting carbon dioxide CO ₂ also takes place with the release of a certain amount of additional heat:

CaO + CO ₂ = CaCO ₃ .

The fine powder of calcium oxide CaO 32 particles necessary for the absorption of carbon dioxide CO ₂ during the initial start-up and periodically during operation is fed into the reactor 1 from above by a sealed charge 25.

Fluidization of coal particles 31 with superheated steam is performed at a pressure of 0.6 ... 0.8 MPa. The pressure is selected based on the creation of the required height of the fluidized bed, also due to the size of the particles of calcium oxide CaO 32.

Spent calcium oxide CaO and ash 11 are removed from the reactor 1 through a sealed shutter located in the bottom of the reactor 1 (in Fig. The design of the shutter is not shown).

Coarse particles of CaO in a mixture with ash, which are unsuitable for creating a fluidized fluidized bed, are considered spent. The resulting technically pure hydrogen H ₂ with a purity of 98 ... 99% is discharged through a hydrogen outlet pipe to 6 consumers.

The hydrogen flow rate is measured by flow meters 47 and changed by means of an electrically driven control valve 46, which are electrically connected to the computer control unit 42.

Along the upper overflow 37, which is an inclined heat-insulated pipeline, from the upper zone of the reactor 1, particles of calcium carbonate CaCO ₃ 35 and carbon C in the composition of coal are removed into the reactor 2, into which superheated water vapor is also fed from below through pipe 4 at a pressure of 0, 6 ... 0.8 MPa and from above are added particles 34 of fine-grained hematite Fe ₂ O ₃ from cyclone 12.

In reactor 2, at a temperature of about 1020 ... 1050 ° C, the reactions of decomposition of CaCO ₃ and a compound of carbon contained in coal take place with hematite Fe ₂ O ₃ :

CaCO ₃ → CaO + CO ₂ ,

C + Fe ₂ O ₃ = CO ₂ + FeO.

The heated carbon dioxide CO ₂ generated in the reactor 2 is discharged to consumers through a pipe 7 with a valve (the valve design is not shown in Fig.).

The resulting particles 33 of iron oxide FeO are removed through the lower linear overflow 39 into the reactor 3.

Through the bottom flow 38, the particles 32 of calcium oxide CaO, obtained as a result of the decomposition of calcium carbonate CaCO ₃ in the reactor 2, are removed to the reactor 1.

Spent particles of calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ 10 are periodically removed through a sealed shutter located in the bottom of the reactor 2 (the design of the shutter is not shown in Fig.).

Waste particles are particles that are large or have a heterogeneous chemical composition and density and do not participate in the creation of a fluidized fluidized bed.

Instead of the removed spent particles of calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ by loading 9, the required additional amount of calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ is periodically introduced through a sealed shutter (the design of the shutter is not shown in Fig.).

In the heat-insulated reactor 3 at a temperature of 1300 ... 1370 ° C, particles 33 of iron oxide FeO are oxidized to particles 34 of hematite Fe2O3 by oxygen of heated compressed air supplied through pipe 5 by an exothermic reaction

4FeO + O ₂ = 2Fe ₂ O.

Atmospheric air 24 is taken from the outside by a blower 23, heated in a heater 28 located in the furnace 16, and then, under a pressure of 0.6 ... 0.8 MPa, is fed into the reactor 3 from below.

The temperature of the heated air is measured by a thermometer 44 placed in the pipe 5, which generates an electrical signal and transmits it through electrical communication to the computer unit 42.

Heating of atmospheric air 24 occurs due to the heat from combustion in the furnace 16 of pyrolysis gas, which is a by-product in the production of charcoal, using an internal burner 20.

The temperature in the reactor 3 is measured by a thermometer 44 electrically connected to the computer control unit 42.

The blower 23 has an electric drive motor connected electrically to the computer control unit 42, with the help of which, by changing the rotation frequency of the electric motor according to a computer program, the amount of air supplied to the reactor 3 is controlled in accordance with the temperature of air heating in the heater 28 and the temperature in the reactor 3.

The use of a computer control unit 42 for regulating the amount of air supplied by the blower 23 makes it possible to minimize the specific heat consumption for heating the compressed air and provides a positive technical effect in comparison with the known device.

The dust-gas flow from the reactor 3 enters through the upper linear overflow 40 into the cyclone 12, in which the particles 34 of hematite Fe ₂ O ₃ are separated from the heated air flow with a lack of oxygen and this air flow is directed through the pipe 8 to consumers for further use. The separated particles 34 of hematite Fe ₂ O ₃ enter the reactor 2.

The thermally insulated pyrolysis furnace 14 serves for the initial heating of the retort 13 using a combined external burner 21 by burning gaseous or liquid fuel 45 in an air flow supplied by a blower 22, the electric motor of which is electrically connected to the computer control unit 42 with the possibility of adjusting the air flow rate.

After heating the retort 13 and the start of the wood pyrolysis process, the supply of fuel 45 to the burner 21 is stopped.

The blower fan 22 also supplies air for combustion of pyrolysis gas using a burner 20, in which a part of the pyrolysis gas formed in the retort 13 is burned when carbon is produced in the charcoal 31. The rest of the pyrolysis gas is discharged through the pipe 19 to consumers.

The burner 20 is equipped with an electrically driven control valve 46 controlled by block 42.

The amount of air supplied to the furnace 16 is controlled by changing the number of revolutions of the electric motor of the blowing fan 22 at the computer command of the unit 42 in accordance with the temperatures measured by the thermometers 44 inside the retort 13 and inside the furnace 14.

The temperature of the discharged furnace combustion products in the pipe 18 and the temperature of the discharged pyrolysis gases in the pipe 19 are measured by thermometers 44 electrically connected to the computer control unit 42.

The temperatures of the heated water vapor after the steam heater 43 and after the steam superheater 26 are measured by thermometers 44 electrically connected to the computer control unit 42.

The blowing fan 22 supplies air to the primary heat exchanger 41, in which this air is heated by utilizing the heat of the oxygen-deficient air removed through the pipe 8.

The secondary heat exchanger 50 serves to heat air 49 due to the heat of heated hydrogen removed through pipe 6.

The steam heater 43 is used to heat the water vapor supplied through the pipe 29 due to the heat of the furnace combustion products discharged through the pipe 18.

The presence of primary 41 and secondary 50 heat exchangers, steam heater 43 is a distinctive feature that provides a positive technical result in comparison with the known device.

The final positive technical result is that due to the heating of the burner air in the heat recovery units, the enthalpy of the air supplied for combustion increases and, in comparison with the known device, the thermal efficiency of the installation increases, that is, a positive technical effect is achieved.

Heating the steam 29 in the steam preheater 43 increases the superheating temperature of the steam in the steam superheater 26, which leads to fuel savings for the implementation of the hydrogen production process.

The thermal efficiency of the installation in the unit of the pyrolysis furnace 14 during fuel combustion is characterized by the share of useful heat

q ₁ = 100 - q ₂ - q ₃ - q ₄ - q ₅ ,%,

where q ₂ , q ₃ , q ₄ , q ₅ - heat losses with exhaust gases, from chemical and mechanical incompleteness of combustion and from external cooling,%.

Heat losses with exhaust gases q ₂ in the known installation reach 25% of the heat of the combusted fuel.

Therefore, at constant values of q ₃ , q ₄ , q _5, reducing heat losses with exhaust gases q2 by utilizing heat in heat exchangers 41, 50 and in a steam heater 43 in the claimed design allows achieving a positive technical result, which consists in increasing the thermal efficiency of the installation q ₁ .

The inventive installation has a gas analyzer 48, which measures the composition of the furnace combustion products discharged through the pipe 18.

The gas analyzer 48 is electrically connected to the computer control unit 42. Based on the oxygen concentration O ₂ measured by the gas analyzer 48, the computer calculates the excess air factor α by the formula

α = (21-0.1 × O ₂ ) / (21-O ₂ ),

where O ₂ is the oxygen concentration in the furnace combustion products,%. The excess air ratio is the ratio of the actual flow rate of air supplied for combustion to the theoretically required for stoichiometric combustion of a unit of fuel.

The change in the actual amount of air supplied for combustion is made by changing the number of revolutions of the blowing fan 22 with a frequency-controlled electric drive on a computer command from the unit 42.

Theoretically, the required amount of air is set according to the computer program of block 42 in accordance with the heat of combustion of the combusted fuel in burners 20 and 21.

The required optimum temperature level of the pyrolysis process in the retort 13 is maintained by changing the fuel consumption for burners 20 and 21.

Burner 21 is used during the initial start-up of the installation using gaseous or reserve liquid fuel.

To control the fuel consumption in the combined external burner 21 and in the internal burner 20, there are electrically driven control valves 46 electrically connected to the computer control unit 42.

The burner 20 is turned on by opening, on a computer command, an electrically driven control valve 46 to supply a portion of the pyrolysis gas for combustion.

In this case, the supply of fuel 45 to the external burner 21 is stopped by closing the valve 46 on a computer command from the unit 42.

The air required for the operation of the burner 20 enters through the air flow path of the burner 21.

With the computerized maintenance of the excess air ratio α = 1.03 in the furnace 16 by means of computer control of the fuel consumption with the help of electrically driven control valves 46 and the amount of removed hydrogen measured located on the pipe 6 of the flow meter 47, minimization of the specific fuel consumption for hydrogen production is ensured.

The known design does not have a computerized software maintenance of the excess air factor α = 1.03 and the fuel combustion process is carried out with large excess air coefficients α >> 1.03 to prevent harmful emissions of unburned hydrocarbon products into the atmosphere.

Maintaining the excess air ratio α = 1.03 in the claimed installation provides a positive technical result for reducing the heat loss of the fuel being burned in comparison with the known installation.

The proposed installation works as follows.

Reactors 1 and 2 are loaded with the amount of particles of calcium oxide CaO, calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ necessary to excite the reactions.

Timber 15 is loaded through the gateway 17 into the retort 13.

The burner 21, the blowing fan 22 are turned on and fuel 45 is supplied, ignited with an igniter (not shown in the figure) for the initial start-up of the pyrolysis furnace 14 in order to heat the retort 13 and carry out the process of obtaining carbon in the composition of coal particles 31 by pyrolysis of wood particles thirty.

The immediate beginning of the pyrolysis process proceeds without air access at a certain excess pressure in the retort 13 with a closed control valve 46 on the pyrolysis gases outlet pipe 19 at a temperature in the retort of 500 ... 600 ° C.

The beginning of the active stage of the pyrolysis process is characterized by the release of pyrolysis gases through the internal burner 20 into the furnace 16, in which the pyrolysis gases will initially ignite from the torch of the burner 21 and then burn with the release of heat, which goes to superheat the water vapor and obtain hot air.

With the onset of the active stage of pyrolysis, the supply of fuel 45 to the burner 21 is stopped.

Wet water vapor is supplied through pipe 29 for heating and then for superheating and air 24 by blower 23.

The amount of pyrolysis gas used in the furnace 16 is controlled by a computer command from the unit 42 by an electric valve 46 on the burner 20.

After heating the internal volumes of reactors 1 and 2 with superheated steam supplied through pipe 4 and heating the reactor 3 with heated air 51, heated particles of charcoal 31 from retort 13 are fed into the reactor 1 by opening the lock 27.

The height of the fluidized bed in reactors 1 and 2 is controlled by changing the amount of superheated steam supplied through the pipe 4 and the charged amount of particles of calcium oxide CaO, calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ .

Released useful gaseous products are discharged to consumers: hydrogen - through pipe 6, carbon dioxide - through pipe 7, hot air with a lack of oxygen - through pipe 8.

Claims (1)

An installation for the production of heated gases from a carbon-containing material, containing a technologically interconnected carbon conversion reactor, a calcium carbonate decomposition reactor CaCO ₃ , an iron oxide FeO oxidation reactor, a cyclone, a retort, a pyrolysis furnace, a pyrolysis furnace furnace, a wood loading gate, an internal burner, an external a burner, a blower fan, a compressed air blower, a superheater, a coal unloading gate, an air heater, a pre-chamber, an upper crossflow, a lower crossflow, a lower linear crossflow, an upper linear crossflow, characterized in that there are additionally a technologically connected computer control unit, primary and secondary heat exchangers for heating the burner air due to the heat of the exhaust gases after the reactor for the decomposition of calcium carbonate CaCO ₃ and hydrogen, there is a steam heater for heating water vapor due to the use of the heat of the furnace combustion products, there are electrically connected computer control: a gas analyzer, a flow meter and a thermometer located on the pipe for removing combustion products, a control valve, a flow meter and a thermometer, located on a pipe for removing pyrolysis gases, a control valve, a flow meter and a thermometer located on the pipe for supplying wet water vapor, an adjustment valve, a thermometer and a flow meter located on the hydrogen removal pipe, a control valve located on the internal burner, thermometers for measuring the temperature of the medium inside the pyrolysis furnace, the retort and the reactor for oxidizing iron oxide FeO, a thermometer and a flow meter for measuring the temperature and flow rate of superheated steam, a thermometer and a flow meter for measurement of temperature and consumption of compressed air, there is a technological electrical connection of the computer control unit with the electric motors of the drives of the blower fan and compressed air blower with the possibility of changing their speed.

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