Supply method and device for ammonia mixed fuel

Abstract

To provide a technique capable of supplying ammonia mixed fuel gas without deposit.SOLUTION: A method includes processes of: removing CO2 from CO2 containing fuel gas; dehumidifying the fuel gas from which CO2 has been removed; and mixing ammonia in a piping system when the dehumidified fuel gas from which CO2 has been removed is transferred to a fuel gas use facility by using the piping system. In the method, the piping system from a position where ammonia is mixed to the fuel gas use facility is warmed to maintain a temperature of the fuel gas at 60°C or higher. A device includes: a mixer for mixing ammonia in the middle of the piping system for transferring the CO2 containing fuel gas; a heater for heating the piping system from the mixer to the fuel gas use facility to cause the temperature of the fuel gas to become 60°C or higher; a CO2 removal device that is installed in the piping system upstream of the mixer and removes CO2 from the CO2 containing fuel gas; and a dehumidification device installed between the CO2 removal device and the mixer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This invention uses CO gas such as by-product gas from steel mills. 2 The present invention relates to a method for mixing ammonia with a fuel gas and supplying the resulting mixture to a fuel gas facility, and an apparatus for use in the method. Here, the symbol "N" attached to the unit of gas volume represents the standard state, which is a state of temperature 0°C and pressure 101325 Pa. [Background technology]

[0002] In steelworks, hydrogen gas (H 2 By-product gases containing combustible components such as sulphuric acid, hydrocarbons and CO are widely used as fuel. These by-product gases also contain a large amount of impurities. For example, even after desulfurization in chemical plants for purification purposes, the amount of H is about 200 to 3000 Vol.ppm. 2 The by-product gas contains S. The by-product gas also contains CO 2 It contains about 2 to 25 vol.%, and also contains moisture equivalent to a saturated state.

[0003] In recent years, the momentum for carbon neutrality has been gathering momentum, and the use of fuels other than fossil fuels is being considered. As we are in a transitional period in which 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 gas 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 using it as a mixed fuel are being conducted widely. However, ammonia (NH 3 ) is known to be easily soluble in water and to react easily with 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 3However, it has been confirmed that such substances are difficult to handle because they are easily generated.

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

[0006] [Patent Document 1] Japanese Patent Publication No. 54-070095 [Patent Document 2] Japanese Patent Application Publication No. 08-122228 [Patent Document 3] Patent No. 5939189 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the conventional technology has the following problems. The method disclosed in Patent Document 1 can be used for gas analysis, but diluting the fuel gas may make it unusable as a fuel. Also, the technology disclosed in Patent Document 2 is sufficient for removing deposits for the purpose of simply performing gas analysis, but there is a problem that the device configuration cannot be applied as is when ammonia is mixed into the fuel gas.

[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 fuel and the resulting mixture to a fuel gas using facility without producing any precipitates, and an apparatus used for the method. [Means for solving the problem]

[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 A process for dehumidifying the fuel gas from which CO has been removed, and a process for removing CO using a piping system. 2 and mixing ammonia in the middle of the piping system when transporting the fuel gas from which the ammonia has been mixed and which has been dehumidified to a fuel gas using facility, and 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] In addition, the method for supplying ammonia mixed fuel according to the present invention further comprises the steps of: 2 A more preferable solution is to include a step of desulfurizing the contained fuel gas. 2 Containing 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 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 and raises the temperature of the fuel gas to 60°C or higher, and a heating device that is installed in the piping system upstream of the mixer and that mixes the ammonia in the piping system that transports the fuel gas-containing gas, 2 CO from contained fuel gas 2 Remove CO 2 A CO removal device and 2 and a dehumidifier disposed between the removal device and the mixer.

[0012] In addition, the ammonia mixed fuel supply device according to the present invention further includes a CO 2 A more preferable solution would be to provide a desulfurization device that removes sulfur from the fuel gas. Effect of the Invention

[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 ammonium carbonate or ammonium hydrogen carbonate from precipitating and clogging the piping. Therefore, it is possible to supply ammonia-mixed fuel as a fuel gas that contributes to a stable carbon neutrality. In addition, the amount of CO 2 By removing CO, the heating value of the fuel gas is increased, which is expected to create added value. 2 When the fuel gas contains sulfur, the desulfurization can be performed using a desulfurization device, which can reduce the catalytic effect of the sulfur content causing ammonium carbonate to precipitate. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing a schematic configuration of an ammonia mixed fuel supply device according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is a schematic diagram showing a schematic configuration of an ammonia mixed fuel supply device used in Examples 1 and 2. [Diagram 3] FIG. 11 is a schematic diagram showing a schematic configuration of an ammonia mixed fuel supply device used in Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiments of the present invention will be described in detail. Note that the drawings are schematic and may differ from the actual ones. Furthermore, the following embodiments are merely examples of devices and methods for embodying the technical idea of ​​the present invention, and are not intended to limit the configuration to the following. In other words, the technical idea 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 the by-product gas from the steel mill and found that the by-product gas contained hydrogen gas (H 2In particular, even after desulfurization in chemical plants for the purpose of purifying by-product gas, there are still many impurities, such as 100 to 3,000 Vol.ppm of H. 2 It contains sulfur (S) derived from S, and also contains saturated moisture.

[0017] First, ammonia is mixed into the by-product gas to produce ammonia NH 3 , water H 2 O and carbon dioxide CO 2 In the presence of H 2 This section explains the formation of precipitates from gases that also contain sulfur such as S.

[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. Ammonium carbonate decomposes at 58°C, releasing ammonia (NH 3 , water H 2 O and carbon dioxide CO 2 become.

[0019] Ammonium hydrogen carbonate (NH 4 )HCO 3 > Ammonium hydrogen carbonate precipitates as colorless crystals when concentrated ammonia water is cooled and carbon dioxide is added to it. Its properties are that ammonium hydrogen carbonate decomposes at 60°C and ammonia NH 3 , water H 2 O and carbon dioxide CO 2 become.

[0020] <Ammonium carbamate NH 2 COONH 4 > Reaction of dry ice with liquid ammonia or an alcoholic solution of ammonia with CO 2It 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 mixing ammonia into the fuel gas, we investigated a method to suppress the deposition of ammonium carbonate, ammonium hydrogen carbonate, etc. An example of an ammonia-mixed fuel supply device is shown in Figure 1.

[0022] Carbon dioxide gas in by-product gas 2 CO 2 Not only does it cause deposition, but it also does not contribute to the combustion reaction. Therefore, carbon dioxide gas (CO) is not generated from the by-product gas. 2 By removing CO, the calorific value per unit volume of fuel gas can be improved. 2 It is preferable that the amount of CO is less than 1 vol.%. 2 The removal device 4 is, for example, a device for removing carbon dioxide gas (CO2) by contacting the gas with an alkali or the like. 2 In addition, the carbon dioxide gas CO in the by-product gas 1 can be absorbed as carbonate. 2 or carbon monoxide CO to ammonia NH 3 This reacts with methane CH 4 , hydrogen gas H 2 or nitrogen gas N 2 As an example of methanation, the example disclosed in Patent Document 3 can be given.

[0023] The saturated moisture in the by-product gas 1 and the moisture generated 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 deposit inside the dehumidifier 5 and cause blockage of the piping. In addition, CO 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 for mixing the by-product gas 1 with ammonia 6 in a piping system 7 that supplies the by-product gas 1 to a fuel gas usage facility 10. It is preferable that the mixer 8 is capable of controlling the flow rate. A heating device 9 is provided in the piping system for heating 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 a heater that uses electric resistance heating and an external wrap of a steam pipe. It is preferable to heat the fuel gas flowing into the mixer and the ammonia 6 to be supplied to the mixer to 60°C or higher. By doing so, it is possible to suppress a decrease in temperature in the ammonia mixing section. Although there is no upper limit on the temperature, it is preferable to keep the fuel gas after the position where the ammonia 6 is mixed at 100°C or lower in consideration of energy costs.

[0025] The sulfur content in the by-product gas is H 2 If the sulfur content in the by-product gas is 200 vol.ppm or more in terms of sulfur, it is preferable to provide a desulfurization device 3. 2 It is preferable that the sulfur content is less than 200 vol.ppm in terms of sulfur. The desulfurization device 3 generally uses a lime-gypsum method, a water-magnet method, an ammonia method, an electron beam method, a soda method, etc. 2 Either method may be used as long as the S concentration can be reduced to less than 200 vol.ppm. EXAMPLES

[0026] <Example 1> The equipment configuration shown in Figure 2 is 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 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 usage 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 set to 4.9 Nm 3 / h, and the flow rate of the mixed ammonia is 0.7 Nm 3 The composition of the simulated by-product gas 2A was H2 :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 testing, slight deposits of ammonium carbonate and ammonium hydrogen carbonate were found in 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 H 2 :18Vol.%,N 2 :47Vol.%, CO:0Vol.%, CO 2 : Less than 1Vol.%, 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 testing, no deposits of ammonium carbonate or ammonium bicarbonate were found in the piping system.

[0030] <Example 3> The equipment configuration shown in Figure 3 is 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 test was conducted in an atmosphere at room temperature of 15 to 25°C without heating the pipe. The length of the pipe 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 in a dry state was H 2 :25Vol.%,N 2 :27Vol.%, CO:21Vol.%, CO 2 :12Vol.%, CH 4 :15Vol.%,H 2 S: 1250 Vol.ppm. The lower calorific value of this simulated by-product gas 2A was 2563 kcal / Nm 3 (10.72MJ / Nm 3 ) was.

[0031] During a 5-hour gas flow test, the piping became clogged with ammonium carbonate deposits. [Industrial Applicability]

[0032] According to the technology of the present invention, CO 2 When the contained fuel gas is mixed with ammonia and supplied to a fuel gas-using facility, the gas can be supplied without producing any precipitates, so that a carbon-neutral fuel can be supplied stably and the environmental load can be reduced, making the gas industrially useful. [Explanation of symbols]

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

Claims

1. CO ２ CO from contained fuel gas ２ and removing CO ２ dehumidifying the fuel gas from which the carbon dioxide has been removed; CO ２ and a step of mixing ammonia into the piping system when the fuel gas from which the humidifier has been removed and which has been dehumidified is transported to a fuel gas using facility using the piping system, The method for supplying ammonia-mixed fuel comprises heating the piping system from the position where the ammonia is mixed to the fuel gas using facility 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 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 contained fuel gas; a heating device for heating a piping system from the mixer to a fuel gas using facility to raise the temperature of the fuel gas to 60° C. or higher; The CO ２ CO from contained fuel gas ２ CO ２ A removal device; The CO ２ a dehumidifier disposed between the removal device and the mixer; An ammonia mixed fuel supply device comprising:

5. In addition, in advance 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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