JP2023005023A - steam boiler system - Google Patents

Abstract

To improve energy efficiency in a steam boiler system which comprises a steam boiler and a carbon dioxide fuel conversion device and in which fuel oxygen, etc. circulates in a closed loop and to reduce introduction cost by size down of the carbon dioxide fuel conversion device.SOLUTION: A steam boiler system comprises a steam boiler 1, a carbon dioxide fueling device 2, a flow path for sending combustion product gas from the steam boiler to the carbon dioxide fueling device, a flow path for sending converted gas from the carbon dioxide fueling device to the steam boiler, and a flow path for sending oxygen gas from the carbon dioxide fueling device to the steam boiler. The steam boiler generates the combustion product gas by burning converted gas with oxygen gas. The carbon dioxide fueling device reduces the combustion product gas so as to be separated into the converted gas and the oxygen gas. The steam boiler system has a configuration where each gas circulates in a closed loop consisting of the steam boiler, the carbon dioxide fueling device, and each flow path. The steam boiler system comprises a heat exchanger which provides water in a water supply path of the steam boiler with heat energy of at least one of the converted gas and/or the oxygen gas.SELECTED DRAWING: Figure 1

Description

The present invention relates to steam boiler systems.

In order to prevent global warming, the development of technology for reducing the emission of carbon dioxide (hereinafter referred to as "CO ₂ ") is underway. Such technologies include technologies for recovering _CO2 , technologies for storing _CO2 , and technologies for converting and effectively using _CO2 .

A technique for recovering CO ₂ is the chemical absorption method. An aqueous amine solution is used to absorb the _CO2 in the flue gas, the absorbed _CO2 is released from this aqueous solution, and the _CO2 is recovered in a tank or the like. Aqueous amine solutions generate heat when absorbing _CO2 and require heating when releasing _CO2 . Therefore, energy is required for cooling and heating the aqueous amine solution, and reducing such energy is a problem.

There are also techniques for storing captured _CO2 . The collected _CO2 is transported to a storage site, a storage hole is provided deep underground, and the _CO2 is compressed and stored. Cost reduction, preservation of the storage state after storage, safety, and the like are issues to be addressed.

Carbon dioxide capture and storage (CCS) is a combination of _CO2 capture technology and _CO2 storage technology. In CCS, due to the above problems, the development of CCU (Carbon Capture and Utilization), which is a technology for converting captured CO ₂ and making effective use of it, is underway.

For example, there is a method of converting _CO2 into methane ₍ hereinafter referred to as "CH4"). The chemical reaction in this case is represented by the following reaction formula (1).

CO ₂ +4H ₂ →CH ₄ +2H ₂ O Reaction formula (1)
Hydrogen (hereinafter referred to as “H ₂ ”) required in the above Reaction Formula (1) can be obtained by the electrolysis reaction of water represented by the following Reaction Formula (2).

2H ₂ O → 2H ₂ +O ₂ Reaction formula (2)
CH4 is the main component of liquefied natural gas ₍ hereinafter referred to as "LNG") and can be effectively used as a substitute for LNG. Regarding CH ₄ obtained by the reactions represented by the reaction formulas (1) and (2), cost reduction is an issue, and it is required to make it comparable to LNG.

In the electric power sector, efforts are being made to reduce _CO2 emissions by reducing the proportion of fossil fuel-burning thermal power generation and increasing the proportion of renewable energy such as solar and wind power generation.

In recent years, the introduction of renewable energy such as solar power and wind power has increased, and the amount of power generated varies depending on the day and time of day, and if an oversupply of power is expected, we will refrain from accepting renewable energy in advance. something is happening.

If electricity is generated while the acceptance of renewable energy is stopped, it will become surplus electricity, so one possible way to utilize it is to produce H ₂ by the electrolysis reaction of water represented by the above reaction formula (2). ing. If H ₂ can be produced, CO ₂ can be converted to CH ₄ and reused as fuel as represented by the above reaction formula (1).

US Pat. No. 6,200,000 discloses a system and method consisting of an electrolyser, a reverse water gas shift reactor, and a Fischer-Tropsch reactor for the production of hydrocarbon compounds.

Here, the reaction in the reverse water gas shift reactor is a reaction that converts CO ₂ to CO (carbon monoxide) and is represented by the following reaction formula (3).

_CO2 +H2->CO _{+ H2O} Reaction formula (3)
Also, the reaction in the Fischer-Tropsch reactor is a reaction that produces hydrocarbons such as CH4, and is represented by the following reaction formula ( ₄ ). This reaction is known as the Fischer-Tropsch process.

nCO+( _2n +1)H2→CnH2n _{+ 2 +} nH2O Reaction formula (4)
_CO2 recovery methods include the pressure swing method, in which _CO2 is absorbed from fossil fuel combustion gas at high pressure and then reduced to low pressure to release and recover _CO2 , and the membrane separation method, in which only _CO2 is permeated through a membrane and recovered. methods, processes in which _CO2 is absorbed using an aqueous amine solution and then released for recovery. _H2 is produced by electrolyzing water using electrical energy from renewable or nuclear fuels.

US Pat. No. 5,300,000 discloses supplying a CO2 stream to a solid oxide electrolysis cell (SOEC) unit to produce CO and feeding this CO back into a first syngas stream, thereby removing in the first syngas stream A method is disclosed in which the CO concentration of is enhanced.

In Non-Patent Document 1, using a solid oxide electrolysis cell (SOEC: Solid Oxide Electrolysis Cell), carbon dioxide and water vapor are simultaneously electrolyzed (co-electrolysis) at a high temperature of 500 ° C. or higher, and are combined with hydrogen. The conversion to carbon oxides and the use of the gas and heat resulting from this conversion to produce methane are disclosed.

Japanese Patent Publication No. 2008-533287 Japanese Patent Publication No. 2019-507718

Fuel Cell, Vol. 14, No. 4, pp. 81-86 (2015)

Patent Documents 1 and 2 do not describe oxidation of fuel and reduction of combustion product gas in a nitrogen-free closed space.

An object of the present invention is to improve the energy efficiency and reduce the size of the carbon dioxide fuel conversion system in a steam boiler system having a structure in which fuel, oxygen, etc. circulate in a closed loop, which includes a steam boiler and a carbon dioxide fuel conversion device. To reduce the introduction cost of a carbon dioxide fuel conversion device.

The steam boiler system of the present invention includes a steam boiler, a carbon dioxide fueling device, a combustion product gas flow path for sending a combustion product gas from the steam boiler to the carbon dioxide fueling device, and converting the carbon dioxide fueling device to the steam boiler. A converted gas flow path for sending gas and an oxygen gas flow path for sending oxygen gas from the carbon dioxide fueling device to a steam boiler, wherein the steam boiler burns the converted gas with the oxygen gas to generate a combustion product gas. , the carbon dioxide fuel conversion device reduces the combustion product gas and separates it into converted gas and oxygen gas, and the combustion product gas, converted gas and oxygen gas are sent to the steam boiler, the carbon dioxide fuel conversion device, the combustion product gas flow path , a closed loop composed of a converted gas flow path and an oxygen gas flow path. A heat exchanger is installed to provide either

According to the present invention, in a steam boiler system that includes a steam boiler and a carbon dioxide fuel conversion device and has a configuration in which fuel, oxygen, etc. circulate in a closed loop, energy efficiency is improved and the carbon dioxide fuel conversion device is made smaller. It is possible to reduce the introduction cost of the carbon dioxide fuel conversion device.

1 is an overall configuration diagram showing a steam boiler system of Example 1. FIG. FIG. 2 is an overall configuration diagram showing a steam boiler system of Example 2;

TECHNICAL FIELD The present disclosure relates to a steam boiler system, and relates to a technique for recovering a combustion product gas (exhaust gas) generated in a combustor of the steam boiler and refueling carbon dioxide contained in the combustion product gas.

Examples will be described below with reference to the drawings.

In the embodiment, a system that reuses carbon dioxide generated from a steam boiler used for steam sterilization of medical equipment and food containers, for example, will be described, but it is not limited to this, and fuel combustion It can be applied as long as it has a configuration in which carbon dioxide is generated by

FIG. 1 is an overall configuration diagram showing a steam boiler system of Embodiment 1. FIG.

The steam boiler system shown in this figure includes a steam boiler 1 , a carbon dioxide fuel conversion device 2 , a combustion catalyst unit 3 , a converted gas tank 6 , an oxygen gas tank 7 and a control device 13 .

The steam boiler 1 is connected with a water supply pipe 15 (water supply channel), a steam pipe 16 (steam channel), a fuel gas pipe 17 (fuel gas channel), and an exhaust gas pipe 18 (combustion product gas channel). . The water supply pipe 15 is a pipe for supplying water to the steam boiler 1 from the outside. The water supply pipe 15 is provided with heat exchangers 11-1 and 11-2. A gas flow control valve 10-4 is installed in the fuel gas pipe 17. As shown in FIG. A gas flow control valve 10-5 is installed in the exhaust gas pipe 18. As shown in FIG.

The steam boiler 1 and the carbon dioxide fuel conversion device 2 are connected by piping. A combustion catalyst unit 3 is installed in the middle of this pipe. This pipe is a flow path branched from the exhaust gas pipe 18 generated in the steam boiler 1 . A pressure gauge 9-3, a gas flow meter 8-4, and a gas analyzer 12-2 are installed in the piping between the combustion catalyst unit 3 and the carbon dioxide fuel conversion device 2.

The carbon dioxide fueling device 2 and the converted gas tank 6 are connected by a pipe (converted gas flow path). A cooler 4-1, a pressure gauge 9-4 and a compressor 5-1 are installed in this order along the pipe.

The carbon dioxide fuel conversion device 2 and the oxygen gas tank 7 are connected by a pipe (oxygen gas flow path). A cooler 4-2, a pressure gauge 9-5 and a compressor 5-2 are installed in this order along the pipe.

The converted gas tank 6 and the steam boiler 1 are connected by a pipe (converted gas channel). A gas flow control valve 10-2 and a gas flow meter 8-2 are installed in this order in the middle of this pipe.

The oxygen gas tank 7 and the steam boiler 1 are connected by piping. A gas flow control valve 10-1 and a gas flow meter 8-1 are installed in this order in the middle of this pipe.

A bypass pipe (converted gas bypass channel) from the converted gas tank 6 is connected to the pipe connecting the steam boiler 1 and the combustion catalyst unit 3 . In other words, the channel that connects the steam boiler 1 and the combustion catalyst unit 3 is connected to a converted gas bypass channel that joins part of the converted gas. A gas flow control valve 10-3 and a gas flow meter 8-3 are installed in this order in the middle of this bypass pipe. The converted gas bypass channel may be branched from the converted gas channel on the upstream side of the converted gas tank 6 .

The SOEC electrode material, which is a component of the carbon dioxide fuel conversion device ₂ , is degraded by O2. Therefore, in preparation for the case where O ₂ remains in the exhaust gas sent from the steam boiler 1 to the carbon dioxide fuel conversion device 2, a combustion catalyst unit 3 is provided in the piping from the steam boiler 1 to the carbon dioxide fuel conversion device 2. However, there may be insufficient fuel components to react with the remaining _O2 . In this case, a converted gas containing CO, H2, etc. is supplied to the upstream _side of the combustion catalyst unit 3 via a bypass pipe from the converted gas tank 6, and reacted with the remaining _O2 to generate _O2 . can be removed.

The converted gas tank 6 is equipped with a pressure gauge 9-2 and a gas analyzer 12-1.

The oxygen gas tank 7 is provided with a pressure gauge 9-1. An oxygen supply pipe 19 for supplying oxygen from the outside is connected to the oxygen gas tank 7 . A gas flow control valve 10-6 is installed in the oxygen supply pipe 19. As shown in FIG.

System power 14 is supplied from the outside to the carbon dioxide fuel conversion device 2, the compressors 5-1 and 5-2.

In the steam boiler system, exhaust gas from a steam boiler 1 is converted into fuel by a carbon dioxide fuel conversion device 2 . Then, the fuel gas is cooled to a temperature that can be filled in the converted gas tank 6, then compressed and filled in the converted gas tank 6. - 特許庁

The gas enclosed in the converted gas tank 6 is reused as fuel for the steam boiler 1 . That is, the steam boiler system is a circulation system that repeats combustion and reduction.

The steam boiler 1 is a device that burns fuel with oxygen, heats water with the combustion heat, and obtains steam. The gas (exhaust gas) after combustion is carbon dioxide and water, and its temperature is as high as 200°C to 500°C. Also, the ratio of fuel to oxygen is kept constant so as to generate a stable flame.

This combustion gas is introduced into the carbon dioxide fuel conversion device 2 .

The carbon dioxide fuel conversion device 2 includes a solid oxide electrolysis cell (SOEC), which is a device that converts _CO2 to CO. A SOEC is a device that produces CO and H ₂ from CO ₂ and H ₂ O as raw materials by supplying electric power. In other words, the carbon dioxide fuel conversion device 2 is a device that reduces the exhaust gas generated in the steam boiler 1 .

In addition, the carbon dioxide fuel conversion device 2 may include a device that generates CH ₄ or the like by a catalytic reaction from CO and H ₂ generated in the SOEC.

Furthermore, the carbon dioxide fuel conversion device 2 may be a device that directly generates CH ₄ or the like by a catalytic reaction or the like using a gas containing CO ₂ as a raw material. In this case, the carbon dioxide fuel conversion device 2 may not include the SOEC.

Therefore, the carbon dioxide fuel conversion device ₂ is a device that generates a gas containing CO, CH4, or the like.

CO and H ₂ or CH ₄ or the like (hereinafter referred to as “converted gas”) generated in the carbon dioxide fueling device 2 are sent to a converted gas tank 6 and stored therein. On the other hand, O ₂ generated in the carbon dioxide fuel conversion device 2 is sent to the oxygen gas tank 7 and stored therein. Therefore, CO, H ₂ , CH ₄ and the like generated in the carbon dioxide fueling device 2 are reused as fuel for the steam boiler 1 . Similarly, the O ₂ produced in the carbon dioxide fuelizer 2 is reused as an oxidant in the steam boiler 1 .

A SOEC is a device that electrolyzes water at high temperatures. The SOEC has a three-layer structure of an oxygen electrode, an electrolyte, and a hydrogen electrode, and uses grid power 14 to generate H ₂ from H ₂ O at the hydrogen electrode and O ₂ at the oxygen electrode. Furthermore, as shown in the reaction formula (3) above, H ₂ O and CO are produced by the reverse water gas shift reaction of CO ₂ and H ₂ .

In the SOEC, not all of the CO ₂ is reacted, but a part of it remains, so that the gas at the hydrogen electrode is a mixture of H ₂ O and CO and unreacted H ₂ and CO ₂ .

Therefore, when the carbon dioxide fueling device 2 is substantially composed only of SOEC, the above H ₂ O, CO, H ₂ and CO ₂ constitute the conversion gas. Since the O ₂ generated in the carbon dioxide fuel conversion device 2 is discharged while being physically separated from the converted gas, the converted gas does not contain O ₂ .

The electric power required for the electrolysis reaction of water in the carbon dioxide fuel conversion device 2 and the composition of the converted gas by the reverse water gas shift reaction change depending on the temperature of the gas. Both the electrolysis reaction and the reverse water gas shift reaction in the carbon dioxide fuel conversion device 2 are endothermic reactions. For this reason, the carbon dioxide fuel conversion device 2 also needs to be heated so that the internal gas temperature does not drop.

Furthermore, if the exhaust gas supplied to the carbon dioxide fueling device 2 contains oxygen, the hydrogen electrode of the carbon dioxide fueling device 2 is oxidized and deteriorated. Therefore, it is desirable to install the combustion catalyst unit 3 upstream of the carbon dioxide fuel conversion device 2 to remove O ₂ in the exhaust gas.

The converted gas produced in the carbon dioxide fueling device 2 is cooled by the cooler 4-1 installed downstream of the carbon dioxide fueling device 2, compressed by the compressor 5-1, and sent to the converted gas tank 6. , is stocked. On the other hand, the O ₂ generated in the carbon dioxide fuel conversion device 2 is cooled by the cooler 4-2 installed downstream of the carbon dioxide fuel conversion device 2, compressed by the compressor 5-2, and stored in the oxygen gas tank 7. sent and stored.

The channel pressure of the converted gas cooled by the cooler 4-1 is measured by the pressure gauge 9-4. The flow path pressure of O ₂ cooled by cooler 4-2 is measured by pressure gauge 9-5. The measured values of the pressure gauges 9-4 and 9-5 are transmitted to the control device 13. FIG. The controller 13 controls the outputs of the compressors 5-1 and 5-2 based on the received measurement values of the pressure gauges 9-4 and 9-5. This allows the channel pressure of the conversion gas and _O2 to be stabilized.

The converted gas stored in the converted gas tank 6 and O ₂ stored in the oxygen gas tank 7 are resupplied to the steam boiler 1 . The converted gas in the converted gas tank 6 is also supplied to the combustion catalyst unit 3 and used to remove O ₂ contained in the exhaust gas from the steam boiler 1 .

The flow rate of the converted gas supplied to the steam boiler 1 is measured by a gas flow meter 8-2. The flow rate of the converted gas supplied to the combustion catalyst unit 3 is measured by a gas flow meter 8-3. The flow rate of O ₂ gas supplied to the steam boiler 1 is measured by a gas flow meter 8-1. The flow rates of these gases are respectively controlled by adjusting the opening degrees of gas flow control valves 10-2, 10-3 and 10-1. This control is performed by the control device 13 .

The means for transmitting data of various measured values to the control device 13 and the means for transmitting various control signals from the control device 13 may be wired or wireless. In this figure, it is indicated by a dashed line.

The flow rate ratio of the converted gas and O ₂ gas supplied to the steam boiler 1 is such that stable combustion is achieved in the steam boiler 1 . On the other hand, the converted gas supplied to the combustion catalyst unit 3 has a flow rate such that O ₂ does not remain in the gas after catalytic combustion.

Thus, the H ₂ O and CO ₂ generated in the steam boiler 1 are converted into H ₂ and CO in the carbon dioxide fuel conversion device 2 and supplied to the steam boiler 1 again.

In this manner, the gas inside the system is configured to circulate in a closed loop during steady operation.

With such a configuration, carbon dioxide emissions from the system can be substantially zero (0).

In this embodiment, the symbol a of the heat exchanger 11-1 is connected to the symbol a of the converted gas flow path connected to the carbon dioxide fuel conversion device 2. FIG. The symbol b of the heat exchanger 11-1 is connected to the symbol b of the converted gas flow path connected to the carbon dioxide fuel conversion device 2. FIG.

Further, the symbol c of the heat exchanger 11-2 is connected to the symbol c of the O ₂ gas flow path connected to the carbon dioxide fuel conversion device 2. FIG. The symbol d of the heat exchanger 11-2 is connected to the symbol d of the O ₂ gas flow path connected to the carbon dioxide fuel conversion device 2. FIG.

In other words, the converted gas produced by the carbon dioxide fueling device 2 heats the feed water of the steam boiler 1 via the heat exchanger 11-1. Further, the O ₂ gas generated by the carbon dioxide fueling device 2 heats the feed water of the steam boiler 1 via the heat exchanger 11-2.

The temperature of the converted gas and _O.sub.2 gas generated in the carbon dioxide fuel conversion device 2 is a high temperature of 600.degree. C. to 1000.degree.

By supplying these thermal energies to the feed water pipe 15 of the steam boiler 1, the amount of heat exchange in the converted gas cooler 4-1 and the O ₂ gas cooler 4-2 can be reduced. Either one of the heat exchanger 11-1 and the heat exchanger 11-2 may be used. If the heat exchanger 11-1 is used, the thermal energy of the converted gas is used, and if the heat exchanger 11-2 is used, the heat energy of the O ₂ gas is used. Thermal energy is given to the feed water pipe 15 of the steam boiler 1 .

Thus, by applying the thermal energy of the converted gas of the carbon dioxide fueling device 2 and the O ₂ gas to the water supply pipe 15 of the steam boiler 1, the steam flow rate obtained by the steam boiler 1 can be increased. Moreover, when obtaining the same steam flow rate in the steam boiler 1, the flow rates of the converted gas and the O ₂ gas supplied to the steam boiler 1 can be reduced. As a result, in the gas closed circulation system in which the H ₂ O and CO ₂ generated in the steam boiler 1 are converted into H ₂ and CO in the carbon dioxide fueling device 2 and supplied to the steam boiler again, the carbon dioxide fueling device It is possible to reduce the flow rate of the gas supplied by 2, and it is possible to reduce the size of the carbon dioxide fuel conversion device 2 and the reduction in the electric power required for the electrolysis of water in the above reaction formula (2). This makes it possible to suppress the energy consumption of the entire system. That is, running costs can be reduced.

Furthermore, since the carbon dioxide fuel conversion device can be downsized by reducing the combustion generated gas, it is possible to reduce the introduction cost when adding the carbon dioxide fuel conversion device including SOEC etc. to the existing steam boiler.

FIG. 2 is an overall configuration diagram showing a steam boiler system of a second embodiment.

In the description of this figure, the same configuration as that of the first embodiment is omitted.

In this figure, a bypass pipe 20 (combustion product gas bypass passage) is installed as a branch pipe in the middle of the pipe connecting the steam boiler 1 and the combustion catalyst unit 3 . A bypass pipe 20 is connected to a pipe between the cooler 4-1 and the compressor 5-1. In other words, the bypass pipe 20 is connected upstream of the compressor 5-1. In other words, the converted gas flow path is connected to a combustion product gas bypass flow path that joins part of the combustion gas from the steam boiler 1 . This allows the exhaust gas from the steam boiler 1 to be mixed with the converted gas produced by the carbon dioxide fuel conversion device 2 . The combustion product gas bypass flow path branches off from the middle of the pipe connecting the combustion catalyst unit 3 and the carbon dioxide fuel conversion device 2, and is connected to the pipe between the cooler 4-1 and the compressor 5-1. You may

A gas flow meter 8-5, a pressure gauge 9-6, a cooler 4-3, and a gas flow control valve 10-7 are installed in the bypass pipe 20 in this order.

By providing the bypass pipe 20, the flow rate of the gas supplied to the carbon dioxide fueling device 2 can be reduced, and the carbon dioxide fueling device 2 can be miniaturized.

Also, when the fuel is burned with oxygen in a closed space, the temperature of the combustion product gas rises because there is no nitrogen. Therefore, if the fuel and oxygen are used for complete combustion, the heat-resistant temperature of the materials constituting the combustor of the steam boiler 1 may be exceeded.

By providing the bypass pipe 20, the combustion product gas containing carbon dioxide and the like is mixed with the converted gas. Able to operate below temperature.

The gas flow rate of the bypass pipe 20 is controlled by the controller 13 adjusting the opening degree of the gas flow control valve 10-7 based on the measured values of the gas flowmeters 8-4 and 8-5. The control device 13 may also adjust the opening degree of the gas flow control valve 10-7 based on the measured values of the pressure gauges 9-3 and 9-6.

The exhaust gas components of the steam boiler 1 are H ₂ O and CO ₂ , and the flow rate of H ₂ O and CO ₂ supplied to the carbon dioxide fuel conversion device 2 is also reduced by the bypass. The carbon dioxide fuel conversion device 2 needs to generate H ₂ and CO by the above reaction formula (2) and the electrolysis reaction of CO ₂ , and H ₂ O and CO ₂ as raw materials are insufficient.

Therefore, it is desirable to have a configuration for supplying water to the combustion product gas flow path between the combustion catalyst unit 3 and the carbon dioxide fuel conversion device 2 .

In this embodiment, the condensed water (drain) collected by the cooler 4-1 that cools the converted gas downstream of the carbon dioxide fuel conversion device 2 is effectively used as the water that is supplied to the combustion product gas flow path. I have to. The collection route is indicated by a thick dashed line in the figure.

The condensed water collected by the cooler 4-1 is stored in the drain tank 21 and supplied downstream of the gas flow meter 8-4 by the water supply pump 22. The water flow is measured by a water flow meter 25, and the control device 13 adjusts the opening of the water flow adjustment valve 24 based on the measured value.

Also, the condensed water (drain) collected by the cooler 4-3 of the bypass pipe 20 can be effectively used. Similarly, the condensed water collected by the cooler 4-3 is stored in the drain tank 21. The collection route in this case is also indicated by a thick dashed line in the figure.

By providing the circulation path 23 in the piping before and after the water supply pump 22, the flow rate can be adjusted even if the water supply pump 22 is not of the inverter system.

The water supplied from the drain tank 21 to the carbon dioxide fuel conversion device 2 is desirably supplied in the form of steam. Using external power to generate steam does not reduce energy consumption, so the heat energy of the high-temperature converted gas or _O2 gas from the carbon dioxide fueling device 2 or the high-temperature gas in the bypass pipe 20 is used for heating. I am trying to

In this embodiment, the symbol p of the heat exchanger 11-4 is connected to the symbol p of the converted gas flow path connected to the carbon dioxide fuel conversion device 2. FIG. The symbol q of the heat exchanger 11-1 is connected to the symbol q of the converted gas flow path connected to the carbon dioxide fueling device 2. FIG.

Further, the symbol r of the heat exchanger 11-5 is connected to the symbol r of the O ₂ gas flow path connected to the carbon dioxide fuel conversion device 2. FIG. The sign s of the heat exchanger 11-5 is connected to the sign s of the O ₂ gas flow path connected to the carbon dioxide fuel conversion device 2. FIG.

Also, the symbol t of the heat exchanger 11-6 is connected to the symbol t of the bypass pipe 20. As shown in FIG. The sign u of the heat exchanger 11-6 is connected to the sign u of the bypass pipe 20. As shown in FIG.

In other words, the water supplied from the drain tank 21 to the carbon dioxide fuel conversion device 2 is heated by the heat exchangers 11-4, 11-5 and 11-6 to become steam.

With such a configuration, the thermal energy of the high temperature converted gas and O ₂ gas downstream of the carbon dioxide fuel conversion device 2 is recovered, and the condensed water (drainage) recovered by the coolers 4-1 and 4-3 ) can be used as energy for heating to steam.

Although it is desirable from the viewpoint of performance to install all of the heat exchangers 11-4, 11-5, and 11-6, any one or two of them may be installed.

Further, the water supply pipe 15 is provided with a heat exchanger 11-3. The sign e of the heat exchanger 11-3 is connected to the sign e of the bypass pipe 20. FIG. The symbol f of the heat exchanger 11-3 is connected to the symbol f of the bypass pipe 20. As shown in FIG. Thereby, the heat exchanger 11-3 can heat the feed water of the steam boiler 1 with the heat of the exhaust gas of the steam boiler 1.

As for the gas supplied to the carbon dioxide fueling device 2, the gas flow rate increases due to the supply of water or steam, but the gas flow rate is lower than in the case where the bypass pipe 20 is not installed as in the first embodiment. 2 can be further miniaturized.

As in the first embodiment, heat exchangers 11-1 and 11-2 are installed in the feed water pipe 15 of the steam boiler 1. FIG.

The symbol a of the heat exchanger 11-1 is connected to the symbol a downstream of the symbol q of the converted gas flow path connected to the carbon dioxide fueling device 2. FIG. The symbol b of the heat exchanger 11-1 is connected to the symbol b of the converted gas flow path connected to the carbon dioxide fuel conversion device 2. FIG.

The symbol c of the heat exchanger 11-2 is connected to the symbol c downstream of the symbol s of the O ₂ gas flow path connected to the carbon dioxide fuel conversion device 2. FIG. The symbol d of the heat exchanger 11-2 is connected to the symbol d of the O ₂ gas flow path connected to the carbon dioxide fuel conversion device 2. FIG.

Although it is desirable from the standpoint of performance to install all of the heat exchangers 11-1, 11-2, and 11-3, any one or two of them may be installed. In other words, in the water supply passage of the steam boiler 1, the water supply of the water supply passage includes the converted gas flowing through the converted gas passage, the oxygen gas flowing through the oxygen gas passage, and the combustion product gas flowing through the combustion product gas bypass passage. A heat exchanger is provided to provide at least one of the thermal energy.

In the present embodiment, the gas flow rate supplied by the carbon dioxide fueling device 2 can be made even smaller than in the system of the first embodiment, and the carbon dioxide fueling device 2 can be made even smaller than in the system of the first embodiment. Thereby, the electric energy consumed by the carbon dioxide fuel conversion device 2 can be further reduced.

1: steam boiler, 2: carbon dioxide fuel conversion device, 3: combustion catalyst unit, 4-1, 4-2, 4-3: cooler, 5-1, 5-2: compressor, 6: conversion gas tank, 7: Oxygen gas tank, 8-1, 8-2, 8-3, 8-4, 8-5: Gas flow meter, 9-1, 9-2, 9-3, 9-4, 9-5, 9 -6: pressure gauge, 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7: gas flow control valve, 11-1, 11-2, 11-3 , 11-4, 11-5, 11-6: heat exchanger, 12-1, 12-2: gas analyzer, 13: control device, 14: grid power, 15: water supply pipe, 16: steam pipe, 17 : fuel gas pipe, 18: exhaust gas pipe, 19: oxygen supply pipe, 20: bypass pipe, 21: drain tank, 22: water supply pump, 23: circulation path, 24: water volume control valve, 25: water flow meter.

Claims (8)

a steam boiler;
a carbon dioxide fuel conversion device;
a combustion product gas flow path for sending combustion product gas from the steam boiler to the carbon dioxide fuel conversion device;
a converted gas flow path for sending the converted gas from the carbon dioxide fueling device to the steam boiler;
an oxygen gas flow path for sending oxygen gas from the carbon dioxide fuel conversion device to the steam boiler,
the steam boiler combusts the converted gas with the oxygen gas to generate the combustion product gas;
The carbon dioxide fuel conversion device reduces the combustion product gas and separates it into the converted gas and the oxygen gas,
The combustion product gas, the converted gas, and the oxygen gas circulate in a closed loop composed of the steam boiler, the carbon dioxide fuel conversion device, the combustion product gas flow path, the converted gas flow path, and the oxygen gas flow path. having a configuration to
A steam boiler system, wherein a heat exchanger is installed in a water supply channel of the steam boiler to give at least one of thermal energy of the converted gas and the oxygen gas to the water supply of the water supply channel. A combustion catalyst unit is installed in the combustion product gas flow path between the steam boiler and the carbon dioxide fuel conversion device,
2. The steam boiler system according to claim 1, wherein a channel connecting said steam boiler and said combustion catalyst unit is connected to a converted gas bypass channel for joining part of said converted gas. 2. The steam boiler system according to claim 1, wherein said converted gas flow path is connected to a combustion product gas bypass flow path for joining part of said combustion gas of said steam boiler. 3. The steam boiler system according to claim 2, wherein water is supplied to said combustion product gas flow path between said combustion catalyst unit and said carbon dioxide fuel conversion device. A combustion product gas bypass channel for joining a part of the combustion product gas of the steam boiler is connected to the converted gas channel,
having a configuration for supplying water to the combustion product gas flow path between the combustion catalyst unit and the carbon dioxide fuel conversion device,
A cooler is installed in each of the converted gas flow path and the combustion product gas bypass flow path,
3. The steam boiler system according to claim 2, wherein condensed water generated in said cooler is used as said water. The condensed water passage is provided with a heat exchanger that provides at least one of thermal energy of the converted gas, the oxygen gas, and the combustion product gas flowing through the combustion product gas bypass passage. 6. The steam boiler system of claim 5. 4. The steam boiler system according to claim 3, wherein said feed water passage of said steam boiler is provided with a heat exchanger that imparts heat energy of said combustion product gas flowing through said combustion product gas bypass passage to said feed water. A compressor is installed in the converted gas flow path,
4. The steam boiler system of claim 3, wherein said combustion product gas bypass flow path is connected upstream of said compressor.

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