Method and device for supplying ammonia mixed fuel

Abstract

The present invention provides a technology with which it is possible to supply an ammonia mixed fuel gas without having precipitates. The present invention provides a method which comprises: a step for removing CO2 from a CO2-containing fuel gas; a step for dehumidifying the fuel gas from which CO2 has been removed; and a step for mixing ammonia into a piping system when the fuel gas, which has been dehumidified after the removal of CO2, is conveyed, with use of the piping system, to a fuel gas using facility. With respect to this method, the temperature of the fuel gas is maintained at 60°C or higher by heating the piping system from the position, at which ammonia is mixed, to the fuel gas using facility. The present invention provides a device which is provided with: a mixer for mixing ammonia in the middle of a piping system for conveying a CO2-containing fuel gas; a heating device for heating the piping system from the mixer to a fuel gas using facility and setting the temperature of the fuel gas to 60°C or higher; a CO2 removal device which is installed in the piping system in the upstream of the mixer, and removes CO2 from the CO2-containing fuel gas; and a dehumidifier which is installed between the CO2 removal device and the mixer.

Description

Ammonia-blended fuel supply method and device

[0001] The present invention is directed to the production of CO ２ The present invention relates to a method for mixing ammonia with a fuel gas containing ammonia and supplying the mixture to a fuel gas-using facility, and an apparatus for use in the method. Here, the symbol "N" attached to the unit of gas volume represents standard conditions, which are a temperature of 0°C and a pressure of 101,325 Pa.

[0002] In steelworks, hydrogen gas (H ２ By-product gases containing combustible components such as sulphur dioxide, hydrocarbons and CO are widely used as fuel. These by-product gases also contain many impurities. For example, even after desulphurisation in chemical facilities for the purpose of purification, the by-product gases contain about 200 to 3000 vol. ppm of H. ２ The by-product gas contains sulfur. The by-product gas also contains CO ２ It contains about 2 to 25 vol. % of water, and also contains moisture equivalent to a saturated state.

[0003] In recent years, the trend toward carbon neutrality has been gaining momentum, and the use of fuels other than fossil fuels is being considered. As we are in a transitional period where fuel gas is being completely shifted to renewable energy, there is a growing need to mix non-fossil fuels such as hydrogen and ammonia with by-product gases and use them as fuel.

[0004] Hydrogen fuel is generally chemically stable and does not react easily with the components in by-product gases, and experiments are being conducted on it as a mixed fuel. However, ammonia (NH ３ ) is known to be easily soluble in water and to react easily with the components in the by-product gas. For example, the precipitate ammonium carbonate (NH ４ ) ２ CO ３ ・H ２ O and ammonium bicarbonate (NH ４ ) HCO ３ It has been confirmed that it is difficult to handle because it is easily generated.

[0005] As a countermeasure, Patent Document 1 discloses a method for suppressing the precipitation of ammonium carbonate at room temperature when analyzing ammonia in a gas containing carbon dioxide, ammonia, and moisture by injecting an inert gas such as nitrogen or argon to dilute the gas 3 to 10 times. Also, Patent Document 2 discloses the installation of a scrubber to remove ammonium hydrogen carbonate when continuously sampling coal gas.

[0006] JP-A-54-070095 JP-A-08-122228 Patent No. 5939189

[0007] However, the conventional techniques have the following problems. While the method disclosed in Patent Document 1 can be used for gas analysis, diluting the fuel gas may make it unusable as a fuel. Furthermore, the technique disclosed in Patent Document 2 is sufficient for simply performing gas analysis because it can remove deposits, but when ammonia is mixed into the fuel gas, there is a problem that the device configuration cannot be applied as is.

[0008] The present invention has been made in view of the above circumstances, and ２ The present invention aims to provide a method for supplying ammonia mixed with a fuel gas containing ammonia to a fuel gas-using facility without depositing any ammonia, and an apparatus used for this method.

[0009] The method for supplying ammonia-mixed fuel according to the present invention, which advantageously solves the above problems, is ２ CO from contained fuel gas ２ and removing CO ２ dehumidifying the fuel gas from which CO has been removed; ２ and a step of mixing ammonia into the piping system when transporting the fuel gas from which the ammonia has been removed and which has been dehumidified to a fuel gas using facility using a piping system, wherein the piping system from the position where the ammonia is mixed to the fuel gas using facility is heated to maintain the temperature of the fuel gas at 60°C or higher.

[0010] The method for supplying ammonia mixed fuel according to the present invention further comprises the steps of: ２A more preferable solution would be to include a step of desulfurizing the contained fuel gas. ２ The contained fuel gas includes steel mill by-product gas.

[0011] The ammonia mixed fuel supply device according to the present invention, which advantageously solves the above problems, ２ a mixer for mixing ammonia in the middle of a piping system for transporting the CO2-containing fuel gas; a heating device for heating the piping system from the mixer to the fuel gas using equipment to make the temperature of the fuel gas 60°C or higher; and a heating device installed in the piping system upstream of the mixer, which mixes the CO2-containing fuel gas with ammonia in the middle of a piping system for transporting the CO2-containing fuel gas. ２ CO from contained fuel gas ２ CO ２ a CO removal device; ２ and a dehumidifier installed between the removal device and the mixer.

[0012] The ammonia mixed fuel supply device according to the present invention further includes a step of supplying the ammonia mixed fuel to the ammonia mixed fuel in advance. ２ A more preferable solution would be to provide a desulfurization device that removes sulfur from the contained fuel gas.

[0013] According to the present invention, CO ２ In the piping system where ammonia is mixed with the fuel gas, it is possible to prevent precipitation of ammonium carbonate or ammonium bicarbonate and blockage of the piping. Therefore, it is possible to stably supply ammonia-mixed fuel as a fuel gas that contributes to carbon neutrality. ２ By removing CO, the calorific value of the fuel gas can be increased, which is expected to create added value. ２ When the contained fuel gas contains sulfur, desulfurization using a desulfurization device can also reduce the catalytic effect of sulfur content that precipitates ammonium carbonate.

[0014] 1 is a schematic diagram showing a schematic configuration of an ammonia mixed fuel supply device according to one embodiment of the present invention, FIG. 2 is a schematic diagram showing a schematic configuration of an ammonia mixed fuel supply device used in Examples 1 and 2, FIG. 3 is a schematic diagram showing a schematic configuration of an ammonia mixed fuel supply device used in Example 3,

[0015] The following describes in detail embodiments of the present invention. Note that the drawings are schematic and may differ from the actual embodiments. Furthermore, the following embodiments exemplify devices and methods for embodying the technical concept of the present invention, and are not intended to limit the configuration to those described below. In other words, the technical concept of the present invention can be modified in various ways within the technical scope described in the claims.

[0016] The inventors analyzed the components of by-product gases from steel mills and found that the by-product gases contained hydrogen gas (H ２ It was found that the by-product gas contains many impurities in addition to combustible components such as hydrocarbons, CO, etc. In particular, even after desulfurization treatment in chemical plants intended to purify by-product gas, it contains about 100 to 3,000 vol. ppm of H. ２ It contains sulfur (S) derived from S and saturated water.

[0017] Therefore, first, ammonia is mixed into the by-product gas to form ammonia NH ３ , water H ２ O and carbon dioxide CO ２ In the presence of ２ The formation of deposits from gases containing sulfur such as S will now be described.

[0018] <Ammonium carbonate (NH ４ ) ２ CO ３ ・H ２ O> Ammonium carbonate precipitates as colorless crystals with an ammonia odor when the gas is cooled to room temperature, with sulfur (S) acting as a catalyst in the precipitation reaction. As a property of ammonium carbonate, it decomposes at 58°C, producing ammonia NH ３ , water H ２ O and carbon dioxide CO ２ becomes.

[0019] <Ammonium bicarbonate (NH ４ ) HCO ３ Ammonium bicarbonate precipitates as colorless crystals when concentrated aqueous ammonia is cooled and carbon dioxide is added to it. Its properties include decomposition at 60°C, and ammonia NH３ , water H ２ O and carbon dioxide CO ２ becomes.

[0020] <Ammonium carbamate NH ２ COONH ４ > Reaction of dry ice with liquid ammonia or CO in alcohol solution of ammonia ２ It precipitates as colorless crystals. It is stable in dry air. When heated to 60°C, ammonia NH ３ and carbon dioxide CO ２ When heated to about 130°C in a sealed tube, it loses water and becomes urea.

[0021] Focusing on the above-mentioned properties of the precipitates, ２ When ammonia is mixed with a contained fuel gas, a method for suppressing the deposition of ammonium carbonate, ammonium bicarbonate, etc. is investigated. An example of an ammonia mixed fuel supply device 1 is shown in FIG.

[0022] Carbon dioxide CO in by-product gas 2 ２ Not only does it cause deposition but also does not contribute to the combustion reaction. ２ By removing CO, the calorific value per unit volume of the fuel gas can be improved. ２ It is preferable that the CO content is less than 1% by volume. ２ The removal device 4 is, for example, a device for removing carbon dioxide gas (CO 2 ) by contacting it with an alkali or the like. ２ In addition, carbon dioxide CO in the by-product gas 2 can be absorbed as carbonate. ２ and carbon monoxide (CO) and ammonia (NH ３ reacting with methane CH ４ , hydrogen gas H ２ and nitrogen gas N ２ As an example of methanation, an example is disclosed in Patent Document 3.

[0023] The saturated moisture in the by-product gas 2 and the moisture produced by methanation are removed by the dehumidifier 5. The dehumidifier 5 generally cools the gas to dehumidify it, so it must be installed before mixing with ammonia. If the gas is cooled after mixing with ammonia, the above-mentioned deposits may be deposited inside the dehumidifier 5, causing blockage of the piping. ２ It is preferable to install it at the stage subsequent to the removal device 4. The moisture content after dehumidification is preferably a dew point of 10°C or less.

[0024] Furthermore, a mixer 8 is provided in a piping system 7 that supplies the by-product gas 2 to the fuel gas using equipment 10, and mixes the by-product gas 2 with ammonia 6. It is preferable that the mixer 8 is flow-controllable. A heating device 9 is provided in the piping system, and heats the fuel gas after the position where the ammonia 6 is mixed so that the temperature is 60°C or higher. Examples of the heating device 9 include an electric resistance heater and an externally wrapped steam pipe. It is preferable to heat the fuel gas flowing into the mixer and the ammonia 6 to be supplied to 60°C or higher. By doing so, it is possible to suppress a drop in temperature in the ammonia mixing section. Although an upper temperature limit is not specified, it is preferable to keep the fuel gas after the position where the ammonia 6 is mixed to 100°C or lower, taking energy costs into consideration.

[0025] The sulfur content in the by-product gas is H ２ If the sulfur content in the by-product gas in a dry state is 200 vol. ppm or more, it is preferable to provide a desulfurization device 3. ２ It is preferable that the concentration of sulfur is less than 200 ppm by volume. Examples of the desulfurization device 3 include the lime gypsum method, magnesium hydroxide method, ammonia method, electron beam method, and soda method. ２ Any method may be employed as long as it can reduce the S concentration to less than 200 vol. ppm.

[0026] Example 1: In the device configuration shown in FIG. ２A test for supplying an ammonia-mixed fuel was conducted by supplying a simulated by-product gas 2A as the contained fuel gas. The pipe diameter was 20A. The heating device 9 was a steam trace in which a steam pipe was installed along the piping system 7, and the gas temperature was adjusted to 68°C. The length of the piping system 7 from the ammonia mixer 8 to the burner as the fuel gas using equipment 10 was 2m. The simulated by-product gas 2A was configured so that moisture was removed by the dehumidifier 5 upstream of the ammonia mixer 8. The flow rate of the simulated by-product gas 2A was 4.9 Nm ３ / h, and the flow rate of the ammonia to be mixed was 0.7 Nm ３ The composition of the simulated by-product gas 2A in a dry state was H ２ :25Vol. %, N ２ :27Vol. %, CO:21Vol. %, CO ２ :12Vol. %, CH ４ :15Vol. %,H ２ S: Less than 200 vol. ppm. The lower heating value of this simulated by-product gas 2A was 2563 kcal / Nm ３ (10.72MJ / Nm ３ The dew point of the simulated by-product gas 2A after dehumidification was 9°C.

[0027] After 100 hours of gas flow test, slight deposits of ammonium carbonate and ammonium hydrogen carbonate were found on the piping system.

[0028] Example 2 Using the same apparatus configuration as in Example 1, carbon dioxide gas CO was produced by methanation as the simulated by-product gas 2A. ２ The fuel gas used was one from which H had been removed. The pipe diameter and gas flow rate were the same as in Example 1. The composition of the simulated by-product gas 2A in a dry state was: ２ :18Vol. %, N ２ :47Vol. %, CO:0Vol. %, CO ２ : Less than 1 Vol.%, CH ４ :35Vol. %,H ２ S: Less than 200 vol. ppm. The lower heating value of this simulated by-product gas 2A was 3474 kcal / Nm ３ (14.53MJ / Nm ３ The dew point of the simulated by-product gas 2A after dehumidification was 9°C.

[0029] After 100 hours of gas flow test, no deposits of ammonium carbonate or ammonium hydrogen carbonate were found in the piping system.

[0030] Example 3: In the device configuration shown in FIG. ２ A test for supplying an ammonia-mixed fuel was conducted by supplying a simulated by-product gas 2A as the contained fuel gas. The pipe diameter was 20A. The test was conducted in an atmosphere at room temperature of 15 to 25°C without heating the pipe. The length of the piping system 7 from the ammonia mixer 8 to the burner as the fuel gas using equipment 10 was 2m. The gas flow rate was the same as in Example 1. The simulated by-product gas 2A was in a saturated moisture state. The composition of the simulated by-product gas 2A was H in a dry state. ２ :25Vol. %, N ２ :27Vol. %, CO:21Vol. %, CO ２ :12Vol. %, CH ４ :15Vol. %,H ２ The lower heating value of this simulated by-product gas 2A was 2563 kcal / Nm ３ (10.72MJ / Nm ３ ) was.

[0031] After 5 hours of gas flow testing, the pipe became clogged with ammonium carbonate deposits.

[0032] According to the technology of the present invention, CO ２ When ammonia is mixed with the contained fuel gas and supplied to a facility using the fuel gas, the mixture can be supplied without deposits, which allows for a stable supply of carbon-neutral fuel and reduces the environmental load, making the method industrially useful.

[0033] 1 Ammonia mixed fuel supply device 2 By-product gas (CO ２ Containing fuel gas) 2A Simulated by-product gas 3 Desulfurization device 4 CO ２ Removal device 5 Dehumidifier 6 Ammonia 7 Piping system 8 (Ammonia gas) mixer 9 Heating device 10 Fuel gas using equipment (burner)

Claims

1. CO ２ CO from contained fuel gas ２ and removing CO ２ dehumidifying the fuel gas from which CO has been removed; ２ and mixing ammonia into a piping system when transporting the fuel gas from which the ammonia has been removed and which has been dehumidified, to a fuel gas usage facility through the piping system, wherein the piping system from a position where the ammonia is mixed to the fuel gas usage facility is heated to maintain the temperature of the fuel gas at 60° C. or higher.

2. Furthermore, the CO ２ 2. The method of claim 1, further comprising the step of desulfurizing the contained fuel gas.

3. The above CO ２ 3. The method for supplying ammonia-mixed fuel according to claim 1 or 2, wherein the contained fuel gas is a by-product gas from an ironworks.

4. CO ２ A mixer that mixes ammonia in the middle of a piping system that transports the fuel gas-containing gas; a heating device that heats the piping system from the mixer to the fuel gas-using equipment to make the temperature of the fuel gas 60° C. or higher; and a heating device that is installed in the piping system upstream of the mixer and that mixes the CO ２ CO from contained fuel gas ２ CO ２ A CO removal device. ２ a dehumidifier disposed between the removal device and the mixer.

5. In addition, ２ 5. The ammonia-mixed fuel supply system according to claim 4, further comprising a desulfurization device for removing sulfur from the fuel gas.

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