RU2737155C1 - Apparatus for processing hydrocarbon biomass to obtain hydrogen-containing gases with high energy potential - Google Patents

Abstract

FIELD: gas industry.SUBSTANCE: invention relates to production of hydrogen-containing gases with high energy potential from solid hydrocarbon biomass and can be used in power engineering. Plant for producing hydrogen-containing gases from hydrocarbon biomass comprises a fluidized bed reactor 1 for converting carbon with a hydrogen supply pipeline 6 to consumers, fluidized bed reactor 2 for decomposition of calcium carbonate CaCO3with carbon dioxide supply pipeline 7 to consumers, cyclone 12 with hot air supply pipeline 8 with oxygen shortage to consumers and reactor 3 for oxidation of iron oxide FeO. Fluid bed reactor 1 for carbon conversion has superheated steam supply pipe 4, CaO calcium loading supplement channel 25, channel 11 for removal of waste calcium oxide CaO and ash. Reactor of boiling layer 2 is connected by top 37 and bottom 38 overflows with reactor of boiling layer 1 and has channel 9 of additional loading of calcium carbonate CaCO3and hematite Fe2O3and channel 10 for removal of spent calcium carbonate CaCO3and hematite Fe2O3. Reactor 3 for oxidation of iron oxide FeO has compressed hot air supply pipeline 5 and is connected by bottom linear overflow 39 with fluidized bed reactor 2 for decomposition of calcium carbonate CaCO3, and upper linear overflow 40 with cyclone 12, which is connected to reactor of boiling layer 2. Pyrolysis furnace 14 is additionally installed in the plant, which contains furnace 16 with combustion products combustion products outlet channel 18, inclined prechamber 36, retort 13 for pyrolysis of hydrocarbon biomass with pyrolysis gas discharge channel to consumers 19. Retort for pyrolysis of hydrocarbon biomass has superheater 26 with pipeline of wet steam supply to overheating and internal burner for pyrolysis gas combustion in furnace, wherein superheater is connected to superheated steam supply pipe to fluidized bed reactor for carbon conversion and boiling bed reactor for decomposition of calcium carbonate CaCO3, as well as external burner 21 with blowing fan 22 and air heater of compressed air 28, connected to compressed air pump 23, which is connected to atmospheric air suction channel 24, note here that compressed air heater is communicated via compressed air feed pipeline with FeO oxidation furnace.EFFECT: reduced costs when producing hydrogen-containing gases.1 cl, 1 dwg

Description

The invention relates to the field of construction of devices for producing hydrogen by converting hydrocarbon biomass. The installation can be used to obtain practically pure hydrogen for subsequent power generation or its use in fuel cells of hydrogen energy.

Known installation containing technologically interconnected fluidized bed reactor for the conversion of carbon with a pipe for removing hydrogen to consumers, a fluidized bed reactor for decomposition of calcium carbonate CaCO ₃ with a pipe for removing carbon dioxide to consumers, a cyclone with a pipe for removing hot air with a lack of oxygen to consumers, a reactor for oxidation iron oxide FeO, while the fluidized bed reactor for carbon conversion has an inclined prechamber for loading hydrocarbon biomass, a superheated steam supply pipe, an additional feed channel for calcium oxide CaO, a channel for removing spent calcium oxide CaO and ash, a fluidized bed reactor for the decomposition of calcium carbonate CaCO ₃ , connected to the upper and lower process flows with a fluidized bed reactor for carbon conversion and having a superheated steam supply pipe, a channel for additional charging of calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ , a channel for removing spent calcium carbonate CaCO ₃ and g nematite Fe ₂ O ₃ , and the reactor for oxidation of iron oxide FeO has a pipe for supplying compressed heated air and is connected by a lower linear overflow with a fluidized bed reactor for decomposition of calcium carbonate CaCO ₃ , and an upper linear overflow with a cyclone, which is connected to a fluidized bed reactor for decomposition calcium carbonate CaCO ₃ , crushed wood is used as a hydrocarbon biomass, from which charcoal is obtained, for which the installation has a pyrolysis furnace, which contains a furnace with a pipe for removing furnace combustion products, a loading sluice with a feed channel for crushed wood, an unloading sluice for wood particles coal, a retort for pyrolysis of wood with a pipe for removing pyrolysis gas to consumers, connected through an unloading lock and an inclined pre-chamber with a fluidized bed reactor for carbon conversion, while the retort for pyrolysis of wood has a superheater with a pipe for supplying wet steam for superheating and an internal burner for burning pyrol exhaust gas in the furnace, and the superheater is connected to the pipe for supplying superheated water vapor to the fluidized bed reactor for carbon conversion and to the fluidized bed reactor for decomposition of calcium carbonate CaCO ₃ , and also has an external burner with a blower fan and a valve on the fuel supply pipe, an air heater compressed air connected to a compressed air blower, which is connected to an atmospheric air suction pipe, and the compressed air heater is connected by a compressed heated air supply pipe to a reactor for oxidizing iron oxide FeO (see. description of the patent for the invention of the Russian Federation No. 2615690). Disadvantages of the known device:

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

2. The temperature level of the wood pyrolysis process is not regulated to increase the thermal efficiency of the installation.

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

This problem is technically solved by using computerized program control to obtain the minimum specific heat consumption for hydrogen production.

The design of the inventive device is shown in Fig. 1, where the arrows indicate the directions of the technological movement of components and working media, and the positions indicate the following elements and assemblies:

1 - fluidized bed reactor for carbon conversion,

2 - fluidized bed reactor for the decomposition of calcium carbonate CaCO₃,

3 - reactor for oxidation of iron oxide FeO,

4 - superheated steam supply pipe,

5 - pipe for supplying compressed heated air,

6 - a pipe for removing hydrogen to consumers,

7 - a pipe for removing carbon dioxide to consumers,

8 - pipe for removing hot air with a lack of oxygen to consumers,

9 - channel for additional loading of calcium carbonate CaCO₃ and hematite Fe₂O₃,

10 - channel for removing waste calcium carbonate CaCO₃ and hematite Fe₂O₃,

11 - channel for the removal of spent calcium oxide CaO and ash,

12 - cyclone,

13 - retort for producing charcoal,

14 - pyrolysis oven,

15 - feed channel for chopped wood,

16 - firebox of the pyrolysis furnace,

17 - gateway for loading chopped wood,

18 - pipe for removal of furnace combustion products,

19 - pipe for withdrawing pyrolysis gas to consumers,

20 - internal burner for burning pyrolysis gas in the furnace,

21 - combined external burner,

22 - blower fan,

23 - compressed air blower,

24 - pipe for suction of atmospheric air,

25 - channel for additional loading of calcium oxide CaO,

26 - superheater,

27 - unloading gate for charcoal particles,

28 - compressed air heater,

29 - pipe for supplying wet steam for superheating,

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 CaCO₃,

36 - inclined prechamber,

37 - upper process flow,

38 - lower process flow,

39 - lower linear flow,

40 - upper linear crossflow,

41 - blast air heater,

42 - computerized program control unit,

43 - steam heater,

44 - thermometer,

45 - fuel supply pipe,

46 - adjusting valve,

47 - flow meter,

48 - gas analyzer.

Dotted lines indicate electrical connections of the computerized program control unit 42 with temperature sensors 44, with electrically driven control valves 46, a blower fan 22, a compressed air blower 23, a flow meter 47 and a gas analyzer 48.

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

The fluidized bed reactor 1 for carbon conversion is structurally a sealed heat-insulated container (thermal insulation is not conventionally shown in Fig.), Having mushroom-shaped nozzles at the bottom of the hearth, through which superheated steam supplied through pipe 4 is continuously blown.

The carbon required for the conversion in the form of charcoal particles 31 up to 12 mm in size is obtained directly as part of the installation in the retort 13, located inside the pyrolysis furnace 14, from the crushed wood 30 supplied through the channel 15 of the crushed wood supply through the sealed sluice 17.

From the retort 13, particles 31 of heated charcoal with residual heated gaseous pyrolysis products are fed through the discharge gate 27 and the inclined prechamber 36 into the reactor 1.

The unloading sluice 27 is a large-sized electrically operated fire-resistant valve that blocks the access of the chopped wood through the inclined prechamber 36 to the reactor 1.

Superheated water vapor is obtained by feeding humid water vapor through a pipe 29 for superheating into a superheater 26, located in the retort 13 and in the firebox of the pyrolysis furnace 16. The steam is superheated due to the heat of the wood pyrolysis process in the retort 13 and due to the heat of combustion released by the pyrolysis gas in the burner 20.

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

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 finely dispersed powder from particles 32 of calcium oxide CaO required for the absorption of carbon dioxide CO ₂ during the initial start-up and additional loading is fed into the reactor 1 from above through the sealed channel of the additional loading 25.

Fluidization of coal particles 31 with superheated water vapor is performed at a pressure of 6 ... 8 kg / cm ² . The pressure is selected based on the creation of the required fluidized bed height, also due to the particle size 32 of calcium oxide CaO.

Spent calcium oxide CaO and ash are removed from the reactor 1 through a channel 11 with a sealed shutter located in the bottom of the reactor 1 (in Fig. 1 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 the hydrogen outlet pipe 6 to consumers.

The hydrogen flow rate is measured by flow meters 47 and controlled by an electrically driven valve 46, which are electrically connected to a computerized program control unit 42 (in Fig. 1, the designations of the position numbers of all valves are the same).

Through the upper process flow 37, which is an inclined heat-insulated pipeline, from the upper zone of the reactor 1, particles of CaCO ₃ and carbon C in the composition of coal are removed into reactor 2, into which superheated water vapor is also fed from below through pipe 4 at a pressure of 6 ... 8 kg / cm ² 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 with hematite Fe ₂ O ₃ proceed:

The heated carbon dioxide CO ₂ generated in the reactor 2 is removed through the upper pipe 7 with a valve (in Fig. 1, the valve design is not shown).

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

Through the lower process 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 are removed through the channel 10 with a gate located in the bottom of the reactor 2 (in Fig. 1, the gate design is not shown).

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

Through channel 9 with a shutter (in Fig. 1, the design of the shutter is not shown), the required additional amount of calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ is introduced.

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 Fe ₂ O _{3 by} oxygen of heated compressed air supplied through pipe 5 by an exothermic reaction

4FeO + O ₂ = 2Fe ₂ O ₃ .

Atmospheric air through the pipe 24 is taken from outside by the blower 23, is heated in the heater 28 located in the furnace 16, and then, under a pressure of 6 ... 8 kg / cm ^2, is fed into the reactor 3 from below.

The temperature of the heated air is measured by a thermometer placed in the pipe 5, which generates an electrical signal and transmits it via electrical connection to the computerized 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 transmit a signal to a computerized program control unit 42.

The supercharger 23 has an electric motor connected electrically to a computerized program control unit 42, with the help of which, by changing the rotational speed 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 the unit 42 for computer control of 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 supplied through a pipe 45 in an air stream supplied by a blower 22, the electric motor of which is electrically connected to a computerized program control unit 42 with the possibility of regulation air flow.

At the initial stage, after heating the retort 13 and the start of the process of pyrolysis of wood in the retort 13, the fuel supply to the burner 21 is stopped. The blower fan 22 supplies air only for combustion of pyrolysis gas using a burner 20, in which only a part of the pyrolysis gas formed in the retort 13 when carbon is produced in the charcoal 31 is burned. The rest of the pyrolysis gas is removed through the channel 19 to consumers.

The burner 20 is equipped with an electrically driven control valve 46 with remote computerized control from the unit 42 (in Fig. 1, the position numbers of all electrically driven control valves are the same).

The amount of air supplied to the furnace 16 is regulated 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 thermometers inside the retort 13 and inside the furnace 14 (in Fig. 1, thermometers are designated conventionally by the same reference numbers).

The temperature of the outgoing furnace and pyrolysis gases, steam after the steam heater 43 and after the steam superheater 26 is measured by thermometers electrically connected to the computerized control unit 42.

After the blowing fan 22, the air is heated in the heater 41 due to the utilization of heat removed through the pipe 18 of the furnace combustion products. Due to this, the enthalpy of the air supplied for combustion increases and, in comparison with the known device, the thermal efficiency of the installation increases on average by 7-11%, that is, a positive technical effect is achieved.

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 loss with exhaust gases, from chemical and mechanical incompleteness of combustion and from external cooling,%.

At constant values of q ₃ , q ₄ , q _{5, a} decrease in heat loss with exhaust gases q ₂ is decisive and in a known installation reaches up to 25%. Accordingly, the q ₂ index in the claimed installation is higher, where the thermal efficiency by reducing losses on average reaches 36%.

In the inventive installation, the utilization of the heat of the furnace combustion products in the preheater 41 for heating the blast air and the utilization in the steam preheater 43 of the heat of the pyrolysis gas removed through the pipe 19 for heating the steam reduces the heat loss with the exhaust gases q₂... This provides a positive technical effect of the claimed installation, compared with the known installation.

The inventive installation has a gas analyzer 48 that measures the composition of the furnace combustion products discharged through pipe 18. The gas analyzer 48 is electrically connected to a computerized control unit 42. Based on the oxygen concentration O ₂ measured by the gas analyzer 48, the computer calculates the excess air factor α according to the formula

α = (21-0.1 × О ₂ ) / (21- О ₂ ),

where О ₂ is the oxygen concentration in the furnace combustion products,%.

The change in the actual amount of air supplied for combustion is made by changing the number of revolutions of the blower fan 22 with a frequency-controlled electric drive on command from the computer program of unit 42, taking into account 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 regulate 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 computerized unit 42 (in Fig. 1, the position numbers of all valves are the same).

The burner 20 starts up after the installation reaches the mode of obtaining pyrolysis gas used in this burner 20 as fuel. The burner 20 is switched on by opening, on a computer command, an electrically driven control valve for supplying pyrolysis gas for combustion.

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

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 computerized regulation of the fuel consumption using electrically driven control valves 46 and the amount of produced hydrogen measured by the computerized flow meter 47, it minimizes the specific fuel consumption for hydrogen production.

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

In this case, heat is consumed for heating the ballast air, the heat of which, with the exception of that which is useful in the heater 41, is emitted as losses into the environment.

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.

Pre-loading of reactors 1 and 2 is performed with the amount of particles of calcium oxide CaO, calcium carbonate required to excite reactions CaCO₃ and hematite Fe₂O₃...

Finely chopped wood 30 is loaded through channel 15 and sluice 17 into retort 13. Combined burner 21 with a blower fan 22 is switched on and gaseous or liquid fuel is supplied, ignited by means of an igniter (in Fig. 1, the igniter is not conventionally shown) for the initial start-up of the pyrolysis furnace 14 to work to heat the retort 13 and implement the process of obtaining carbon in the composition of coal particles 31 by pyrolysis of wood particles 30.

Directly, the pyrolysis process proceeds without air access at a certain excess pressure in the retort 13 with a closed control valve on the pipe 19 at a temperature in the retort of 500 ... 600 ° C at the final stage.

During the pyrolysis process, a pyrolysis gas of the following composition is formed:

Components Content,% vol. C _n H _m 19 ... 29% CH ₄ 33 ... 45% H ₂ 12 ... 28% CO 11 ... 18% CO ₂ 1.5 ... 2.5%

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 to the combined burner 21 is stopped. Wet steam is supplied for superheating through pipeline 29 and air through pipe 24 by blower 23 for heating in order to obtain superheated steam and to obtain compressed heated air 5.

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

After heating the internal volumes of reactors 1, 2 and 3 with superheated steam and heated air, heated charcoal is fed into reactor 1 from retort 13 by opening the discharge gate 27.

The height of the fluidized bed in reactors 1 and 2 is controlled by changing the amount of water vapor supplied from below through the pipe 4 and the amount of particles of calcium oxide CaO, calcium carbonate CaCO₃ and hematite Fe₂O₃...

The released useful gaseous products are discharged to consumers: hydrogen - through pipe 6, carbon dioxide - through pipe 7, hot air - through pipe 8.

The set of technical solutions of the proposed installation according to the calculated data can increase the efficiency of the installation by 17% in comparison with the known installation.

Claims (1)

Installation for the processing of hydrocarbon biomass to produce hydrogen-containing gases with high energy potential, containing technologically interconnected fluidized bed reactor for carbon conversion with a pipe for removing hydrogen to consumers, a fluidized bed reactor for decomposing calcium carbonate CaCO ₃ with a pipe for removing carbon dioxide for consumers, a cyclone with a pipe removal of hot air with a lack of oxygen to consumers, a reactor for the oxidation of iron oxide FeO, while the fluidized bed reactor for carbon conversion has an inclined prechamber for loading hydrocarbon biomass, a pipe for supplying superheated water vapor, a channel for additional loading of calcium oxide CaO, a channel for removing spent calcium oxide CaO and ash, a fluidized bed reactor for the decomposition of calcium carbonate CaCO ₃ , connected to the upper and lower process flows with a fluidized bed reactor for carbon conversion and having a pipe for supplying superheated steam, a channel for additional charging of coal calcium acid CaCO ₃ and hematite Fe ₂ O ₃ , a channel for the removal of spent calcium carbonate CaCO ₃ and hematite Fe ₂ O ₃ , and the reactor for the oxidation of iron oxide FeO has a compressed heated air supply pipe and is connected by a lower linear flow to the fluidized bed reactor for the decomposition of carbon dioxide. calcium CaCO ₃ , and the upper linear overflow with a cyclone, which is connected to the fluidized bed reactor for the decomposition of calcium carbonate CaCO ₃ , is used as a hydrocarbon biomass crushed wood, from which charcoal is obtained, for which the unit has a pyrolysis furnace, which contains a furnace with a pipe for removing furnace combustion products, a loading sluice with a feed channel for chopped wood, an unloading sluice for charcoal particles, a retort for pyrolysis of biomass wood with a pipe for removing pyrolysis gas to consumers, connected through an unloading sluice and an inclined pre-chamber with a fluidized bed reactor for carbon conversion, while retort for pyrolysis wood the first biomass has a superheater with a pipe for supplying wet steam for superheating and an internal burner for burning pyrolysis gas in the furnace, and the superheater is connected to a pipe for supplying superheated steam to a fluidized bed reactor for carbon conversion and to a fluidized bed reactor for decomposition of calcium carbonate CaCO ₃ , and also has an external burner with a blower fan and a valve on the fuel supply pipe, a compressed air air heater connected to a compressed air blower, which is connected to the atmospheric air suction pipe, and the compressed air air heater is connected by a compressed heated air supply pipe to a reactor for oxidizing iron oxide FeO, characterized in that there are additionally a technologically interconnected computerized program control unit, a blast air heater, a gas analyzer and a thermometer located on the exhaust pipe of the furnace combustion products, a steam heater, a control valve a and a thermometer located on the pyrolysis gas outlet pipe, a control valve and a thermometer located on the wet steam supply pipe, a control valve and a flow meter located on the hydrogen outlet pipe, a control valve located on the internal burner, there are thermometers for measuring the temperature of the medium inside the pyrolysis furnace, retort and reactor for oxidation of iron oxide, temperature of superheated steam and heated compressed air, there is a technological electrical connection of a computerized program control unit with control valves, a flow meter, a gas analyzer, with thermometers, with electric motors of drives of a blower fan and a compressed air blower with the possibility of changing them rotation frequency.

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