Manufacturing apparatus and method for operating manufacturing apparatus

Abstract

Provided are a manufacturing facility and a method for operating the manufacturing facility, which are capable of efficiently generating ammonia gas capable of suppressing emission of carbon dioxide as a fuel gas for a heating unit such as a heating furnace. The manufacturing equipment comprises a heating part for heating a target material, a manufacturing line for processing the target material heated by the heating part, a circulating water processing device for processing circulating water for cooling in the heating part and the manufacturing line, and a supply circulating water path for supplying the circulating water from the circulating water processing device to the heating part and the manufacturing line. A recovery circulating water path for recovering circulating water from the heating part and the manufacturing line to the circulating water treatment device; and an ammonia gas generation device for supplying ammonia gas for combustion to the heating part. The ammonia generation device comprises a liquid ammonia storage part, an ammonia vaporizer which vaporizes liquid ammonia supplied from the liquid ammonia storage part through heat exchange with sensible heat in circulating water, and an ammonia gas supply part which supplies ammonia gas obtained through heat exchange in the ammonia vaporizer to the heating part.

Description

Technical Field

[0001] The present invention relates to a manufacturing apparatus including a heating section for heating an object and a method for operating the manufacturing apparatus. Background Technology

[0002] In integrated steel plants, byproduct gases generated in converters and coke ovens, exemplified by blast furnace gases discharged from the top of blast furnaces that reduce iron ore to produce molten iron, are effectively utilized (reused) as fuel gases. However, with the increasing demands for carbon dioxide emission reduction in recent years, combustion technologies to reduce the use of these byproduct gases are needed. For example, even in heating furnaces used to heat steel in hot rolling lines and heavy plate rolling lines of integrated steel plants, it is necessary to reduce the use of byproduct gases and decrease carbon dioxide emissions. In this context, the technology of utilizing ammonia as fuel gas for heating furnaces has attracted attention. Ammonia, which contains no carbon, primarily produces water and nitrogen when burned, thus resulting in a significant reduction in carbon dioxide emissions. Therefore, there is a desire to develop technologies for using ammonia as fuel gas in heating furnaces.

[0003] Ammonia, used as a fuel for combustion, is transported and stored in a liquid state. If liquid ammonia is directly burned, its high latent heat of vaporization leads to incomplete evaporation during combustion, reducing its conversion efficiency into heat energy. Therefore, to obtain the required combustion energy, an excess of liquid ammonia needs to be supplied as fuel, increasing ammonia consumption. On the other hand, if liquid ammonia is pre-vaporized before combustion, pre-heating for vaporization is required, necessitating additional energy.

[0004] In response, Patent Document 1 discloses an ammonia vaporizer that uses the heat of combustion exhaust to vaporize liquid ammonia as a combustion device for gas turbines, etc. The combustion exhaust of the burner is maintained at a temperature of, for example, around 800°C, so liquid ammonia can be easily vaporized by utilizing heat exchange with the gas passing through the exhaust system of the burner.

[0005] Furthermore, Patent Document 2 discloses a device for combustion devices such as gas turbines that generates water vapor from the exhaust gas of a gas turbine, and then generates ammonia vapor by spraying liquid ammonia into the flow path of the generated water vapor. In this case, the liquid ammonia can be vaporized by heat exchange between the high-temperature water vapor and the liquid ammonia.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2015-190466

[0009] Patent Document 2: Japanese Patent Application Publication No. 2020-165603 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, when the above-mentioned existing technologies are applied to heating equipment such as heating furnaces, the following problems arise.

[0012] The technology described in Patent Document 1 is applicable to situations where large quantities of gas are discharged as exhaust gas, such as in gas turbines, and where the exhaust gas has a high sensible heat. However, in heating equipment such as industrial furnaces, regenerative burners are mostly used, and the sensible heat of the exhaust gas is used to preheat the combustion air. Therefore, the exhaust gas from heating equipment does not have enough heat to vaporize ammonia. Furthermore, when the furnace is restarted after maintenance or inspection, it is in a state where no exhaust gas has been generated, thus preventing its use for vaporizing liquid ammonia during the furnace restart phase. Additionally, when using exhaust gas for heat exchange, if the exhaust gas comes into contact with low-temperature piping inside the heat exchanger, the exhaust gas will be below the acid dew point (the temperature at which acidic substances begin to form in the exhaust gas), promoting corrosion of the heat exchanger. This also increases the maintenance load on the heat exchanger.

[0013] Regarding the technology described in Patent Document 2, when using exhaust gas discharged from the heating furnace to generate water vapor, there is a problem that the exhaust gas from the heating furnace does not have enough heat to vaporize the necessary ammonia. Furthermore, when restarting the heating furnace after it has been stopped, the sensible heat of the exhaust gas cannot be utilized, and other equipment is needed to generate water vapor.

[0014] The present invention was made in view of the above circumstances, and its object is to provide a manufacturing apparatus and a method of operating the manufacturing apparatus, which can efficiently generate ammonia gas that suppresses carbon dioxide emissions using the sensible heat of circulating water with heat.

[0015] Methods for solving problems

[0016] [1] A manufacturing apparatus comprising: a heating section for heating a target material; a manufacturing line for processing the target material heated by the heating section; a circulating water treatment device for treating circulating water used for cooling in the heating section and the manufacturing line; a supply circulating water path for supplying the circulating water from the circulating water treatment device to the heating section and the manufacturing line; a recovery circulating water path for recovering the circulating water from the heating section and the manufacturing line to the circulating water treatment device; and an ammonia generating device for supplying ammonia gas for combustion to the heating section, wherein...

[0017] The ammonia generating apparatus includes: a liquid ammonia storage unit for storing ammonia in a liquid state; an ammonia vaporizer for vaporizing liquid ammonia supplied from the liquid ammonia storage unit through heat exchange with sensible heat in the circulating water; and an ammonia supply unit for supplying ammonia obtained through heat exchange in the ammonia vaporizer to the heating unit.

[0018] [2] The manufacturing equipment as described in [1], wherein the ammonia vaporizer has: a shell connected to the recovery circulating water circuit and through which the circulating water flows; and an ammonia piping through which the liquid ammonia flows and through which the liquid ammonia is vaporized by heat exchange with the sensible heat of the circulating water flowing in the shell.

[0019] [3] The manufacturing equipment as described in [1], wherein the ammonia vaporizer has: a shell connected to the supply circulating water circuit and through which the circulating water flows; and an ammonia piping through which the liquid ammonia flows and through which the liquid ammonia is vaporized by heat exchange with the sensible heat of the circulating water flowing in the shell.

[0020] [4] The manufacturing equipment as described in [1], wherein the ammonia vaporizer has: a shell connected to the recovery circulating water path from the heating section and through which the circulating water flows; and an ammonia piping through which the liquid ammonia flows and through which the liquid ammonia is vaporized by heat exchange with the sensible heat of the circulating water flowing in the shell.

[0021] [5] The manufacturing equipment as described in any one of [1] to [4], wherein the heating section has a conveying device having the recycling water path inside and conveying the object material.

[0022] [6] The manufacturing equipment as described in any one of [1] to [5], wherein the manufacturing line has: an object material cooling device that uses the circulating water to cool the object material and recovers the circulating water used in cooling the object material and allows it to flow into the recovery circulating water path.

[0023] [7] The manufacturing apparatus as described in [6], wherein the ammonia vaporizer has: a shell connected to and through the recycling water path from the object material cooling device; and an ammonia piping through which liquid ammonia is circulated and through which ammonia gas obtained by vaporizing the liquid ammonia through heat exchange with the sensible heat of the circulating water flowing in the shell is circulated.

[0024] [8] The manufacturing equipment as described in any one of [1] to [7], wherein the heating unit has a gas supply unit for supplying gas in order to mix with the ammonia gas supplied from the ammonia gas supply unit.

[0025] [9] An operation method for a manufacturing equipment, wherein, while supplying and recovering circulating water for cooling to a heating unit for heating a material to be heated and a manufacturing line for processing the material, ammonia for combustion is supplied from an ammonia generating unit to the heating unit and manufacturing is performed using a manufacturing equipment having the heating unit and the manufacturing line, the operation method comprises: a liquid ammonia supply step, wherein liquid ammonia is supplied from a liquid ammonia storage unit to an ammonia vaporizer in the ammonia generating unit; an ammonia generation step, wherein the liquid ammonia is vaporized in the ammonia vaporizer by heat exchange with sensible heat in the circulating water, thereby generating ammonia; and an ammonia supply step, wherein the generated ammonia is supplied to the heating unit.

[0026]

[10] The method of operating the manufacturing equipment as described in [9], wherein in the ammonia generation step, the liquid ammonia is vaporized by heat exchange with the sensible heat in the circulating water recovered from the heating section and the manufacturing line, thereby generating ammonia.

[0027]

[11] The method of operating the manufacturing equipment as described in [9], wherein in the ammonia generation step, the liquid ammonia is vaporized by heat exchange with the sensible heat in the circulating water supplied to the heating unit and the manufacturing line, thereby generating ammonia.

[0028]

[12] The method of operating the manufacturing equipment as described in [9], wherein in the ammonia generation step, the liquid ammonia is vaporized by heat exchange with the sensible heat in the circulating water recovered from the heating section, thereby generating ammonia.

[0029]

[13] The method of operating the manufacturing equipment as described in [9], wherein, in the ammonia generation step, the liquid ammonia is vaporized by heat exchange with the sensible heat in the circulating water recovered from the object material cooling device in the manufacturing line, thereby generating ammonia.

[0030] Invention Effects

[0031] According to the present invention, ammonia gas, which suppresses carbon dioxide emissions, can be efficiently generated using the sensible heat of circulating water with heat, and used as fuel gas for the heating section of a furnace or the like. Attached Figure Description

[0032] [ Figure 1 ] Figure 1 This is a diagram showing a schematic side view of an example of a manufacturing device.

[0033] [ Figure 2 ] Figure 2 This is a diagram schematically illustrating the configuration of the circulation path of the circulating water in the manufacturing equipment of the first embodiment.

[0034] [ Figure 3 ] Figure 3 This is a schematic side view showing an example of a heating element.

[0035] [ Figure 4 ] Figure 4 This is a schematic cross-sectional view showing an example of a heating element.

[0036] [ Figure 5 ] Figure 5 This is a schematic diagram showing an example of an ammonia generating device.

[0037] [ Figure 6 ] Figure 6 This is a schematic diagram showing an example of an ammonia vaporizer.

[0038] [ Figure 7 ] Figure 7 This is a schematic diagram showing an example of a combustion device.

[0039] [ Figure 8 ] Figure 8 This is a schematic diagram showing a modified example of a combustion device.

[0040] [ Figure 9 ] Figure 9 This is a diagram schematically illustrating the configuration of the circulation path of the circulating water in the manufacturing equipment of the second embodiment.

[0041] [ Figure 10 ] Figure 10 This is a diagram schematically illustrating the configuration of the circulation path of the circulating water in the manufacturing equipment of the third embodiment.

[0042] [ Figure 11 ] Figure 11 This is a diagram schematically illustrating the configuration of the circulation path of the circulating water in the manufacturing equipment of the fourth embodiment.

[0043] [ Figure 12 ] Figure 12 This is a schematic diagram showing the configuration of the ammonia vaporizer as described in the fifth embodiment. Detailed Implementation

[0044] <First Implementation>

[0045] The first embodiment of the present invention will be described in detail below. Figure 1The diagram shows a schematic side view of one example of manufacturing equipment 1. Manufacturing equipment 1 includes a heating unit 10 and a manufacturing line 2. Manufacturing line 2, in the conveying direction D of the target material S, sequentially includes, from the upstream side, a descaling device 20, a width-reducing pressing device 30, a roughing rolling device 40, a finishing descaling device 50, a finishing rolling device 60, a target material cooling device 70, and a winding machine 80. Here, the target material S can be steel such as cast slabs or steel plates.

[0046] Heating section 10 heats the target material S. Heating section 10 may be a heating furnace for heating the target material S. Heating section 10 heats the target material S to a predetermined temperature and is used before rolling, forging, heat treatment, etc., of the target material S. Manufacturing line 2 performs at least one of the following treatments on the target material S heated by heating section 10: processing, cooling, surface treatment, etc. Manufacturing line 2 may be a hot rolling line for steel.

[0047] After the target material S is loaded into the heating section 10, it is heated to a predetermined set temperature and then extracted from the heating section 10. The target material S extracted from the heating section 10 has its primary oxide scale removed by the descaling device 20, and then its width reduced to a predetermined set width by the width-reducing pressing device 30. Then, the widened target material S is rolled to a predetermined thickness in the roughing rolling mill 40, thus becoming a slab blank (rough-rolled material), which is then conveyed to the finishing rolling mill 60. Upstream of the finishing rolling mill 60, the secondary oxide scale formed on the surface of the target material S is removed by the finishing descaling device 50. Then, in the finishing rolling mill 60, the target material S is rolled to the product thickness using a continuous rolling mill with 5 to 7 stands (rolling mills).

[0048] A material cooling device 70, including a run-out table, is provided downstream of the finishing mill 60. After the material S is cooled to a predetermined temperature, it is wound into a coil using a winding machine 80. Additionally, a roughing descaling device can be provided upstream or downstream of the roughing mill 40 to appropriately remove the secondary oxide scale generated in the roughing process of the material S. Furthermore, water-cooled nozzles for cooling the material S during finishing milling can be provided between the stands of the finishing mill 60.

[0049] Next, use Figure 2 Explain the composition of the circulation path of the circulating water W in manufacturing equipment 1. Figure 2 This is a schematic diagram illustrating the circulation path of the circulating water W in manufacturing equipment 1. (See diagram for example.) Figure 2As shown, in addition to the heating unit 10 and the manufacturing line 2, the manufacturing equipment 1 also includes a circulating water treatment device 8, a supply circulating water path P, a recovery circulating water path R, and an ammonia generation device 3. The circulating water treatment device 8 treats the circulating water W used for cooling in the heating unit 10 and the manufacturing line 2.

[0050] In the manufacturing equipment 1 including the heating section 10, circulating water is supplied for cooling purposes to suppress the temperature rise of the machine constituting the manufacturing equipment 1 and to protect the machine. Especially in the heating section 10, since the interior becomes a high-temperature atmosphere, circulating water W is required to protect the equipment. Furthermore, as mentioned above, in the manufacturing equipment 1, circulating water W is used for cooling and descaling the target material S. For example, in a hot rolling line, the circulating water supplied to the heating section 10 is approximately 1500 to 3000 ton / hr, and the circulating water supplied to the target material cooling device 70 for cooling the target material S is approximately 6000 to 8000 ton / hr, a large amount of circulating water is supplied. In addition, in a hot rolling line where the target material S is a thick plate, the circulating water W supplied to the heating section 10 is approximately 1000 to 2500 ton / hr, and the circulating water W supplied for cooling the target material S is approximately 6000 to 8000 ton / hr. Therefore, this circulating water W is reused by using a circulation path that includes a supply circulating water path P and a recovery circulating water path R. Additionally, in manufacturing line 2, the object material cooling device 70 uses circulating water W to cool the object material S, and recovers the circulating water W used in cooling the object material S and circulates it through the recovery circulating water path R.

[0051] Here, use Figure 2 The structure of the circulating water treatment device 8 is explained. The circulating water treatment device 8 removes foreign matter and regulates the temperature of the recycled circulating water Rw, which is supplied to the manufacturing equipment 1 after cooling the equipment machinery and the target material S, and then supplies it back to the manufacturing equipment 1. For example... Figure 2As shown, the circulating water treatment device 8 includes a sedimentation tank 8a, a filter 8b, a cooling tower 8c, a storage tank 8d, and a water supply unit 8e. The sedimentation tank 8a is a device used to separate foreign matter with a density greater than water, such as scale, contained in the recycled circulating water Rw by sedimentation. The filter 8b is a device that uses a filtration device to separate solid components contained in the recycled circulating water Rw. The cooling tower 8c, also called a cooling tower, is a type of heat exchanger that cools the recycled circulating water Rw by direct or indirect contact with the atmosphere. The cooling tower 8c is equipped with a fan and uses the heat of vaporization to cool the recycled circulating water Rw. The storage tank 8d is a device for temporarily storing the recycled circulating water Rw. The purpose of the storage tank 8d is to ensure that the amount of circulating water W supplied to the manufacturing equipment 1 remains stable even if the amount of circulating water W used in the manufacturing equipment 1 varies. The water supply unit 8e is a device that supplies the circulating water W stored in the storage tank 8d to the manufacturing equipment 1.

[0052] In the manufacturing equipment 1, which includes the heating unit 10, the temperature of the circulating water W rises due to the cooling of the equipment and the cooling of the target material S. Therefore, a cooling tower 8c is needed to release heat from the recycled circulating water Rw. In this case, the heat removed from the recycled circulating water Rw by the cooling tower 8c in the hot rolling line is about 50 to 90 MW.

[0053] Here, as Figure 2 As shown, the supply circulating water path P is a circulation path from the circulating water treatment device 8 to each machine (heating unit 10 and manufacturing line 2) of the manufacturing equipment 1, supplying circulating water Pw. The recovery circulating water path R is a circulation path that returns the recovered circulating water Rw supplied for cooling in each machine (heating unit 10 and manufacturing line 2) of the manufacturing equipment 1 back to the circulating water treatment device 8. Supply circulating water Pw cooled by the cooling tower 8c of the circulating water treatment device 8 flows in the supply circulating water path P. Recovered circulating water Rw whose temperature has increased due to being supplied to each machine of the manufacturing equipment 1 flows in the recovery circulating water path R. Furthermore, supply circulating water Pw is supplied from the water delivery unit 8e of the circulating water treatment device 8 to the supply circulating water path P, and is supplied to each machine through branches of the circulation path. In this case, in order to regulate the amount of supply circulating water Pw supplied to each machine, a flow regulating valve and a flow meter can be appropriately configured. On the other hand, in the recycling water path R, the circulating water Pw supplied and the machine unit supplied with the circulating water Pw are respectively recycled as recycled circulating water Rw, and are merged through the circulation path, thereby recovering foreign matter and the like in the sedimentation tank 8a of the circulating water treatment device 8.

[0054] Next, use Figure 3 and Figure 4 Explain the structure of the heating section 10. Figure 3 A schematic side view is shown as an example of the heating section 10. Figure 4A schematic cross-sectional view is shown as an example of the heating unit 10. The heating unit 10 includes a loading section 11, a combustion device 12, a conveying device 13, an extraction section 14, and a flue section 15. For example, in the case where the manufacturing line 2 is a hot rolling line, the heating unit 10 is used to heat the target material S, such as the cast slab, to a specified temperature (approximately 1100 to 1300°C). The combustion device 12 heats the target material S by burning ammonia gas (Ag) as fuel gas.

[0055] The loading section 11 loads (transfers) the target material S, which is to be heated, into the interior of the heating section 10. The extraction section 14 extracts (transfers) the heated target material S to the outside of the heating section 10. For example, steel such as slabs manufactured in a continuous casting line (target material S) is transported to the loading side area of ​​the heating section 10 and loaded into the interior of the heating section 10 from the loading section 11 according to the production plan of the hot rolling line, etc. The interior of the heating section 10 is divided into multiple zones, with a heating zone divided into 2 to 8 zones on the upstream side and 1 to 3 heat exchange zones on the downstream side. During the operation of the heating section 10, the temperature is controlled such that each zone inside is controlled to a different atmosphere temperature, and the average temperature of the target material S loaded into the heating section 10 gradually rises to a predetermined target heating temperature (the target temperature of the target material S when extracted from the heating section 10).

[0056] The heating unit 10 has a conveying device 13 inside for continuously conveying the object material S from the loading unit 11 to the extraction unit 14. The conveying device 13 has a fixed conveying part 13a such as a fixed slide and a movable conveying part 13b such as a conveying slide. The fixed conveying part 13a and the movable conveying part 13b have support parts that support the object material S being conveyed. The fixed conveying part 13a is fixed inside the heating unit 10. The movable conveying part 13b lifts and conveys the object material S. That is, the movable conveying part 13b conveys the object material S to the extraction unit 14 by repeatedly lifting, moving forward, lowering, and retracting inside the heating unit 10. The fixed conveying part 13a and the movable conveying part 13b are in direct contact with the heated object material S, and are therefore easily deformed or damaged due to the high temperature. Therefore, the fixed conveying section 13a and the mobile conveying section 13b have circulation paths (supply circulation path P and recovery circulation path R) through which circulating water W for cooling the fixed conveying section 13a and the mobile conveying section 13b can circulate. By allowing the circulating water W to circulate inside the fixed conveying section 13a and the mobile conveying section 13b, deformation and breakage can be prevented.

[0057] The heating section 10 has multiple combustion devices 12, such as burners, inside along the conveying direction D of the target material S. The combustion devices 12 heat the interior of the heating section 10 through combustion. When the interior of the heating section 10 is heated by the combustion of the combustion devices 12, the temperature of the target material S rises due to radiation from the wall 16 of the heating section 10. In addition, an atmospheric gas flow is generated inside the heating section 10, and the target material S is heated due to the convection of this atmospheric gas. Alternatively, the target material S can also be heated by contacting the combustion flame of the combustion devices 12 with the target material S.

[0058] The combustion devices 12 are configured corresponding to multiple zones inside the heating section 10. It should be noted that the number of zones and the number of combustion devices 12 are not necessarily the same. An example of a heating section 10 is shown... Figure 3 Inside the heating section 10, five combustion devices 12 are arranged on the upper surface of the target material S, extending from the loading section 11 towards the extraction section 14. Additionally, five more combustion devices 12 are arranged on the lower surface of the target material S, for a total of ten combustion devices 12. Fuel gas and fuel air are supplied to each combustion device 12. The fuel gas burns by diffusion in the air, and the combustion flame is blown into the interior of the heating section 10. While air is typically used for fuel air, oxygen, oxygen-enriched air, or a mixture of oxygen and exhaust gas can also be used as oxygen-containing gases.

[0059] Additionally, a schematic cross-sectional view of the heating section 10 as viewed from the conveying direction D of the object material S is shown. Figure 4 As shown, in order to avoid a temperature difference between the right and left sides, in the direction perpendicular to the conveying direction D of the object material S, it is desirable to arrange the combustion device 12 on the right and left sides of the object material S respectively.

[0060] Furthermore, the heating section 10 may include a combustion device 12 that does not use ammonia (Ag) as fuel gas. That is, it may include a burner device that uses conventional carbonaceous gases as fuel gas. Although burner devices using carbonaceous gases as fuel gas emit carbon dioxide, by using ammonia (Ag) as fuel gas for the heating section 10 as a whole, carbon dioxide emissions can be reduced.

[0061] Next, use Figure 5 Explain the composition of ammonia generating device 3. Figure 5A schematic diagram of an example ammonia generating apparatus 3 is shown. The ammonia generating apparatus 3 supplies ammonia gas for combustion to the heating unit 10. The ammonia generating apparatus 3 includes a liquid ammonia storage unit 4, an ammonia vaporizer 5, an ammonia supply unit 6, and a liquid ammonia pump 7. The liquid ammonia storage unit 4 is a container for storing ammonia in a liquid state. The ammonia vaporizer 5 vaporizes the liquid ammonia Al supplied from the liquid ammonia storage unit 4 through heat exchange with the sensible heat in the circulating water W. The ammonia supply unit 6 supplies the ammonia gas Ag obtained through the heat exchange in the ammonia vaporizer 5 to the heating unit 10. Additionally, the liquid ammonia storage unit 4 supplies liquid ammonia Al at a flow rate corresponding to the rotational speed of the liquid ammonia pump 7 to the liquid ammonia pump 7. The liquid ammonia pump 7 draws liquid ammonia Al from the liquid ammonia storage unit 4, pressurizes the liquid ammonia Al, and supplies it to the ammonia vaporizer 5.

[0062] In this embodiment, the heating unit 10 uses ammonia (Ag) as fuel gas in at least one combustion device 12. The combustion device 12 using ammonia (Ag) as fuel gas employs an ammonia generating device 3, which generates ammonia (Ag) by vaporizing liquid ammonia (Al). However, the ammonia generating device 3 may also be configured to be connected to multiple combustion devices 12, and to supply ammonia (Ag) as fuel gas from one ammonia generating device 3 to multiple combustion devices 12.

[0063] The ammonia vaporizer 5 uses the sensible heat of the circulating water W to vaporize the liquid ammonia Al supplied from the liquid ammonia storage section 4. A heat exchanger is used in the ammonia vaporizer 5. As long as the heat exchanger is configured such that the high-temperature side is the circulating water W and the low-temperature side is the liquid ammonia Al, it is not limited to heat exchange methods such as plate heat exchangers or multi-tube heat exchangers (shell and tube heat exchangers).

[0064] Next, use Figure 6 Explain the composition of the ammonia vaporizer 5 in the ammonia generating device 3. Figure 6 A schematic diagram of a sample ammonia vaporizer 5 is shown. Figure 6 A multi-tube heat exchanger is shown as an example of a heat exchanger used in an ammonia vaporizer 5. The ammonia vaporizer 5 has a shell 5a and ammonia piping 5b. The ammonia vaporizer 5 has a configuration in which ammonia piping 5b, which are multiple tubes, are arranged inside the shell 5a, which is a container.

[0065] like Figure 6 As shown, liquid ammonia Al flows inside the ammonia pipe 5b, and circulating water W flows inside the shell 5a, thereby exchanging heat between the circulating water W and the liquid ammonia Al, and the liquid ammonia Al vaporizes to generate ammonia gas Ag.

[0066] That is, in this embodiment, also considering Figure 2The ammonia vaporizer 5, as shown, has a shell 5a that is connected to the recovery circulating water line R to allow circulating water W to flow through. It also has an ammonia piping 5b through which liquid ammonia Al and ammonia gas Ag flow, the ammonia gas Ag being obtained by vaporizing the liquid ammonia Al through heat exchange with the sensible heat of the circulating water W flowing in the shell 5a.

[0067] The ammonia supply unit 6 supplies ammonia gas (Ag) vaporized by the ammonia vaporizer 5 to the combustion device 12 in the heating unit 10. The ammonia supply unit 6 may include a pump for supplying ammonia gas (Ag) to the combustion device 12 in the heating unit 10, a flow regulating valve for adjusting the amount of ammonia gas (Ag) supplied to the combustion device 12 which uses ammonia gas (Ag) as fuel gas, and a flow meter.

[0068] Next, use Figure 7 The configuration of the combustion device 12 in the heating section 10 is explained. Figure 7 This is a schematic diagram showing an example of the combustion device 12. The combustion device 12 includes a combustion section 12a, an ammonia supply passage 12b, a combustion air supply passage 12e, and a fluid confluence section 12f. The ammonia supply passage 12b includes an ammonia regulating valve 12c and an ammonia flow meter 12d. The ammonia supply passage 12b is connected to the ammonia supply section 6 in the ammonia generating device 3. The ammonia supply passage 12b allows ammonia gas (Ag) supplied from the ammonia supply section 6 to flow to the combustion section 12a.

[0069] Ammonia regulating valve 12c regulates the supply of ammonia gas (Ag). Ammonia flow meter 12d measures the flow rate of ammonia gas (Ag). The supply of ammonia gas (Ag) is regulated in a manner that ensures the thermal energy required to heat the target material S to a specified temperature in the heating section 10.

[0070] like Figure 7 As shown, ammonia gas (Ag) is mixed with combustion air (O) in the fluid confluence section 12f. Energy saving is achieved by preheating the combustion air (O) before mixing it with ammonia gas (Ag) using exhaust gas or similar methods.

[0071] The combustion device 12 can also be a regenerative burner in which two burners 12 integrated with the heat storage body alternately burn at intervals of tens of seconds. In the case of the regenerative burner, when one burner 12 is burning, the exhaust gas from one burner 12 is passed through the heat storage body of the other burner 12, heating the heat storage body and thus recovering the heat energy from the exhaust gas of one burner 12. Then, when the other burner 12 is burning, the exhaust gas from the other burner 12 is passed through the heat storage body of one burner 12 for heating. This allows for the operation of the heating unit 10 with excellent energy efficiency.

[0072] Next, use Figure 8The configuration of a modified example of the combustion device 12 in the heating section 10 is explained. Figure 8 A schematic diagram of a combustion device 18, a variant of the combustion device 12, is shown. (Except for...) Figure 7 In addition to the components of the combustion device 12 shown, the combustion device 18 also includes a gas supply unit 12g, a gas supply path 12h, a gas mixing unit 12k, and a gas supply control unit 12l. The gas supply path 12h includes a gas regulating valve 12i and a gas flow meter 12j.

[0073] like Figure 8 As shown, the combustion device 18 can be configured to use a mixture of ammonia (Ag) and coal gas (Cg), i.e., a coal-ammonia mixture (ACg), as the fuel gas. That is, in order to mix with the ammonia (Ag) supplied from the ammonia supply unit 6 in the ammonia generation device 3, the heating unit 10 can also have a coal gas supply unit 12g that supplies coal gas (Cg). The gas mixing unit 12k mixes the ammonia (Ag) and coal gas (Cg). The coal gas regulating valve 12i regulates the flow rate of coal gas (Cg) supplied from the coal gas supply unit 12g. The coal gas flow meter 12j measures the flow rate of coal gas (Cg).

[0074] Combustion device 18 can use a mixture of ammonia (Ag) and coal gas (Cg), i.e., a coal-ammonia mixture ACg, as fuel gas. Furthermore, while the carbon dioxide emission increases when the mixing ratio of coal gas (Cg) in the fuel gas is increased compared to combustion device 12 using ammonia (Ag), the overall carbon dioxide emission of the heating unit 10 can be reduced by including ammonia (Ag) in the fuel gas. Additionally, ammonia (Ag) is a difficult-to-ignite fuel with a slow combustion rate and an unstable combustion state; therefore, mixing it with coal gas (Cg) stabilizes the combustion state and facilitates the heating of the target material S, which is advantageous in this respect.

[0075] The coal gas Cg used in combustion device 18 refers to the gas obtained from coal. Preferably, the coal gas Cg is a byproduct gas generated in blast furnaces, coke ovens, converters, etc., in steel plants. Blast furnace gas is a byproduct gas produced when iron ore is reduced in a blast furnace to produce pig iron. Coke oven gas is a byproduct gas generated during the high-temperature dry distillation of coal to produce coke. Converter gas is a byproduct gas generated during the steelmaking process in a converter.

[0076] Byproduct gases have various compositions due to the processes involved in their formation. For example, a representative composition of blast furnace gases is 21–30% by volume of combustible carbon monoxide, 50–60% by volume of non-combustible nitrogen, and 10–22% by volume of carbon dioxide. A representative example of the lower heating value of blast furnace gases is 3.45 MJ / Nm³. 3The typical composition of coke oven gas is approximately 46–60% by volume, methane 20–35% by volume, carbon monoxide 5–10% by volume, and hydrocarbons such as ethylene 2–4% by volume. A representative example of the lower heating value of coke oven gas is 18.0 MJ / Nm³. 3 The converter gas contains approximately 75% carbon monoxide and 13% carbon dioxide by volume, as well as trace amounts of oxygen, nitrogen, and hydrogen. A representative example of the lower heating value of the converter gas is 8.2 MJ / Nm³. 3 Approximately. Regarding the gas, sometimes a suitable mixture of blast furnace gas, coke oven gas, and converter gas (hereinafter referred to as "M gas") is used. By mixing gases with different calorific values, the heat required for heating steel is supplied, thus enabling stable operation of the steel heating furnace.

[0077] The combustion device 18 includes a gas supply control unit 12l that controls the mixing ratio of ammonia Ag in the coal-ammonia mixture ACg. The gas supply control unit 12l sets or controls the ratio of the opening of the coal gas regulating valve 12i (for coal gas Cg) to the opening of the ammonia regulating valve 12c (for ammonia Ag), thereby controlling the mixing ratio of ammonia Ag in the coal-ammonia mixture ACg. In the combustion device 18, solenoid valves can be used to configure the coal gas regulating valve 12i and the ammonia regulating valve 12c, and the opening of the solenoid valves is controlled in the gas supply control unit 12l to achieve a predetermined mixing ratio of coal gas Cg and ammonia Ag flow rates. By controlling the mixing ratio of ammonia Ag in the coal-ammonia mixture ACg, the gas supply control unit 12l can adjust the combustion energy of the combustion device 18 and change the heating state of the target material S in the heating unit 10. Since the combustion rate of ammonia Ag is slow, increasing the mixing ratio of ammonia Ag reduces the stability of the combustion flame. Therefore, by controlling the mixing ratio of ammonia (Ag) using the gas supply control unit 12l, the combustion stability of the combustion device 18 can be improved.

[0078] In the combustion device 18, as an example, the air used for fuel is 625 Nm. 3 For a rate of / hr, 150 Nm of coal gas can be used. 3 / hr, ammonia gas is 30Nm 3 A mixture of gases at approximately 185 Nm³ / hr is used as fuel gas. Therefore, when using only coal gas as fuel gas, a mixture of gases at approximately 185 Nm³ / hr can be obtained. 3 The same amount of heat per hr.

[0079] Here, refer to Figure 2This description explains the configuration of using the ammonia vaporizer 5 in the ammonia generation device 3 and the sensible heat of the recovered circulating water Rw recovered in the recovered circulating water path R to vaporize liquid ammonia Al. In this embodiment, the recovered circulating water Rw, which is supplied to each machine constituting the manufacturing equipment 1 (heating unit 10 and manufacturing line 2) for cooling and then recovered to the circulating water treatment device 8, is supplied to the ammonia vaporizer 5. It should be noted that a portion of all the recovered circulating water Rw recovered from the recovered circulating water path R can also be branched out and supplied to the ammonia vaporizer 5.

[0080] exist Figure 2 In the embodiment shown, not only the recycled circulating water Rw recovered from the heating unit 10, but also the recycled circulating water Rw recovered from the descaling device 20, roughing device 40, finishing descaling device 50, finishing device 60, target material cooling device 70 and winding machine 80 in the manufacturing line 2 are combined and then connected to the ammonia vaporizer 5.

[0081] Here, in manufacturing equipment 1, it is envisioned that coal gas Cg is used as the fuel gas for the conventional heating section 10. For example, the flow rate of coal gas Cg used in the heating section 10 is 15 to 20 Nm³. 3 At a temperature of / s, the lower heating value of coal gas Cg is 10 MJ / Nm³. 3 In this case, the total calorific value is 150-200 MW. In this case, as in this embodiment, when the coal gas Cg used in the heating section 10 is replaced with ammonia Ag, considering that the lower heating value of ammonia Ag is 14.1 MJ / Nm³... 3 The density of ammonia (Ag) is 0.771 kg / Nm³. 3 The flow rate of ammonia gas (Ag) used to obtain a calorific value equivalent to that of coal gas (Cg) is 8.2–10.9 kg / s. Here, the latent heat of ammonia gas (Ag) is 1.372 MJ / kg, therefore the heat required to obtain such a flow rate of ammonia gas (Ag) through gasification is approximately 11.3–15.0 MW. Furthermore, in the cooling tower 8c of the circulating water treatment unit 8, the heat removed from the circulating water W is approximately 50–90 MW. Therefore, even if ammonia gas (Ag) is used as fuel gas in all combustion devices 12 used in the heating unit 10, the recycled circulating water (Rw) flowing in the recycled circulating water path R has sufficient sensible heat for vaporizing liquid ammonia (A1).

[0082] As described above, even if all the coal gas Cg used as fuel gas in the heating section 10 is replaced with ammonia Ag, sufficient heat (approximately 11.3 to 15.0 MW) can be obtained from the recycled circulating water Rw flowing in the recycled circulating water path R for vaporizing liquid ammonia Al. Furthermore, the ammonia vaporizer 5 will remove an equivalent amount of heat (approximately 11.3 to 15.0 MW) from the recycled circulating water Rw flowing in the recycled circulating water path R. Therefore, the amount of heat that needs to be removed from the recycled circulating water Rw in the cooling tower 8c of the circulating water treatment device 8 is reduced, thus reducing the power consumed in the cooling tower 8c and achieving energy-saving effects in the circulating water treatment device 8.

[0083] From this perspective, the maximum heat that the ammonia vaporizer 5 can obtain from the recycled circulating water Rw can be considered equivalent to the cooling capacity of the cooling tower 8c of the circulating water treatment device 8. That is, the heat removed by the cooling tower 8c of the circulating water treatment device 8 from the recycled circulating water Rw can be utilized as the heat for vaporizing liquid ammonia Al by the ammonia vaporizer 5. In this embodiment, the heating unit 10 can be supplied with ammonia gas Ag as fuel gas in at least one combustion device 12. Therefore, the circulating water treatment device 8 in this embodiment preferably has a cooling capacity of removing more than 5 MW of heat energy, and more preferably more than 50 MW. This is because when the cooling capacity of the circulating water treatment device 8 is less than 5 MW, the recycled circulating water Rw cannot have sufficient sensible heat for vaporizing liquid ammonia Al. It should be noted that although there is no upper limit specified for the cooling capacity of the circulating water treatment device 8, in the manufacturing equipment 1 that includes a large heating unit 10, a cooling capacity of 300 MW is sufficient.

[0084] The recycling water circuit R is preferably configured to recycle recycled water Rw with a flow rate of 1000 ton / hr or more, and the temperature of the recycled recycled water Rw is preferably 20°C or higher. This is because when the flow rate of the recycled recycled water Rw flowing in the recycling water circuit R is less than 1000 ton / hr or the temperature is lower than 20°C, sufficient heat for vaporizing liquid ammonia Al cannot be supplied in the ammonia vaporizer 5. It should be noted that although there are no specific upper limits for the flow rate and temperature of the recycled recycled water Rw in the recycling water circuit R, in the manufacturing equipment 1 that includes a large heating unit 10, the required amount of ammonia Ag for the heating unit 10 can be obtained as long as the flow rate is 300,000 ton / hr or less and the temperature is 80°C or less.

[0085] In this embodiment, the ammonia vaporizer 5 is preferably capable of exchanging at least 5 MW of heat energy from the sensible heat of the recycled circulating water Rw, more preferably at least 50 MW. This is because if the heat exchange capacity of the ammonia vaporizer 5 is less than 5 MW, a sufficient flow of ammonia gas (Ag) cannot be supplied as fuel gas to the heating unit 10. It should be noted that although there is no upper limit specified for the heat exchange capacity of the ammonia vaporizer 5, in a manufacturing apparatus 1 that includes a large heating unit 10, a heat exchange capacity of 300 MW is sufficient.

[0086] As described above, in the first embodiment, the operation method of the manufacturing equipment 1 includes the following steps. Specifically, the operation method of the manufacturing equipment 1, which supplies circulating water W for cooling and recycles it to the heating unit 10 for heating the target material S and the manufacturing line 2 for processing the target material S, and supplies ammonia gas Ag for combustion from the ammonia generating unit 3 to the heating unit 10, includes: a liquid ammonia supply step, in which liquid ammonia Al is supplied from the liquid ammonia storage unit 4 to the ammonia vaporizer 5 in the ammonia generating unit 3; an ammonia generation step, in which the liquid ammonia Al is vaporized in the ammonia vaporizer 5 through heat exchange with the sensible heat in the circulating water W, thereby generating ammonia gas Ag; and an ammonia supply step, in which the generated ammonia gas Ag is supplied to the heating unit 10.

[0087] Furthermore, in the ammonia generation step, liquid ammonia Al is vaporized by heat exchange with sensible heat from the circulating water W recovered from the heating unit 10 and the manufacturing line 2, thereby generating ammonia.

[0088] By using the manufacturing apparatus 1 and its operation method in this embodiment, liquid ammonia Al can be vaporized through heat exchange with the sensible heat in the circulating water W. The resulting ammonia gas Ag is then supplied to the heating unit 10 for heating the target material S. In other words, ammonia gas Ag that suppresses carbon dioxide emissions can be efficiently generated as fuel gas for the heating unit 10. Furthermore, by using the sensible heat of the circulating water W circulating in the manufacturing apparatus 1 to vaporize liquid ammonia Al and use it as fuel gas for the heating unit 10, the additional energy required to convert liquid ammonia Al into fuel gas can be reduced.

[0089] <Second Implementation Method>

[0090] Next, the second embodiment of the present invention will be described in detail. Figure 9 The diagram schematically illustrates the configuration of the circulation path of the circulating water W in the manufacturing apparatus 91 of the second embodiment. Figure 9This illustration shows an example of a configuration in which the ammonia vaporizer 5 uses the sensible heat of the supply circulating water Pw flowing in the supply circulating water path P to vaporize liquid ammonia Al. Furthermore, in the second embodiment, the configuration is the same as in the first embodiment, except for the connection of the ammonia vaporizer 5 to the supply circulating water path P.

[0091] That is, in this embodiment, also considering Figure 9 and Figure 6 The ammonia vaporizer 5, as shown, has a housing 5a connected to the circulating water supply path P, through which circulating water W flows. It also has an ammonia piping 5b through which liquid ammonia Al and ammonia gas Ag flow, the ammonia gas Ag being obtained by vaporizing the liquid ammonia Al through heat exchange with the sensible heat of the circulating water W flowing in the housing 5a.

[0092] In the second embodiment, the supply circulating water Pw, which is supplied for cooling in each machine (heating unit 10 and manufacturing line 2) constituting the manufacturing equipment 91 and flows in the supply circulating water path P, is supplied to the ammonia vaporizer 5. The supply circulating water Pw flowing in the supply circulating water path P is circulating water W whose temperature has been regulated by the circulating water treatment device 8. Therefore, as long as the supply circulating water path P is used, the supply circulating water Pw can also be supplied to the ammonia vaporizer 5 from a branch of the circulation path supplied to any machine.

[0093] And, as Figure 9 As shown, it is preferable to connect the supply circulating water path P, which supplies the supply circulating water Pw for cooling the heating unit 10, to the ammonia vaporizer 5. This is because: by using the supply circulating water Pw flowing in the supply circulating water path P near the heating unit 10, ammonia gas Ag can be generated near the heating unit 10, and the length of the path for supplying ammonia gas Ag can be shortened.

[0094] In the conventional heating section 10 of the manufacturing equipment 91, when using coal gas Cg as fuel gas, if 20% of the fuel gas is replaced with ammonia Ag, the total calorific value of the ammonia Ag required is approximately 30 to 40 MW. The corresponding ammonia Ag flow rate is 1.64 to 2.00 kg / s. The latent heat of ammonia Ag is 1.372 MJ / kg, therefore, the heat required to obtain such a flow rate of ammonia Ag through gasification is approximately 2.25 to 2.74 MW. Furthermore, when the flow rate of circulating water Pw flowing through the circulating water path P towards the heating section 10 is 2100 ton / hr and the temperature of the circulating water W is 34°C, although the temperature of the circulating water W decreases from 34°C to 28°C due to heat exchange in the ammonia vaporizer 5, 14.7 MW of heat can still be supplied to the liquid ammonia A1. Therefore, even when using ammonia (Ag) as fuel gas in the combustion device 12 used in the heating unit 10 at a ratio of approximately 20%, the supply circulating water Pw flowing through the supply circulating water path P has sufficient sensible heat to vaporize liquid ammonia (Al). Furthermore, when the flow rate of the supply circulating water Pw flowing towards the heating unit 10 in the supply circulating water path P is approximately 12,000 ton / hr and the temperature of the circulating water W is approximately 34°C, 66.3 MW of heat can be supplied, thus allowing the fuel gas in the combustion device 12 used in the heating unit 10 to be completely replaced with ammonia (Ag).

[0095] As can be seen from the above, in this embodiment, the supply circulating water path P is preferably a machine that supplies supply circulating water Pw at a flow rate of 1000 ton / hr or more to the heating unit 10 at a location where the supply circulating water Pw branches and flows through the shell 5a of the ammonia vaporizer 5. Preferably, the temperature of the supply circulating water Pw is 30°C or higher. This is because when the flow rate of the supply circulating water Pw flowing towards the heating unit 10 through the shell 5a of the ammonia vaporizer 5 in the supply circulating water path P is less than 1000 ton / hr or the temperature is less than 30°C, sufficient heat for vaporizing liquid ammonia Al cannot be supplied in the ammonia vaporizer 5. Furthermore, as a manufacturing apparatus 91 including a large heating unit 10, as long as the flow rate of the supply circulating water Pw flowing through the shell 5a of the ammonia vaporizer 5 and supplied to the heating unit 10 is 30000 ton / hr or less and the temperature is 80°C or less, a sufficient amount of liquid ammonia Al required for use in the heating unit 10 can be vaporized.

[0096] As described above, in the second embodiment, the operating method of the manufacturing apparatus 1 includes the following steps. That is, for the ammonia generation step in the first embodiment, liquid ammonia Al is vaporized by heat exchange with the sensible heat in the circulating water W supplied to the heating unit 10 and the manufacturing line 2, thereby generating ammonia Ag.

[0097] By means of the manufacturing apparatus 1 and its operation method in this embodiment, liquid ammonia Al can be vaporized through heat exchange with the sensible heat in the circulating water W supplied to the heating unit 10 and the manufacturing line 2. The vaporized ammonia gas Ag is then supplied to the heating unit 10 for heating the target material S. In other words, ammonia gas Ag that suppresses carbon dioxide emissions can be efficiently generated as fuel gas for the heating unit 10. Furthermore, by using the sensible heat of the circulating water W circulating in the manufacturing apparatus 1 to vaporize liquid ammonia Al and use it as fuel gas for the heating unit 10, the additional energy required to convert liquid ammonia Al into fuel gas can be reduced.

[0098] <Third Implementation Method>

[0099] Next, the third embodiment of the present invention will be described in detail. Figure 10 The configuration of the circulation path of the circulating water W in the manufacturing equipment 92 of the third embodiment is shown in a neutral manner. Figure 10 This illustration shows an example of a configuration in which the ammonia vaporizer 5 uses the sensible heat of the recycled circulating water Rw recovered from the heating unit 10 before merging with the recycled circulating water Rw recovered from each of the equipment in the manufacturing line 2 to vaporize liquid ammonia Al. Furthermore, in the third embodiment, the configuration is the same as in the first embodiment, except that the ammonia vaporizer 5 is connected to the recycled circulating water path R from the heating unit 10.

[0100] That is, in this embodiment, also considering Figure 10 and Figure 6 The ammonia vaporizer 5, as shown, has a shell 5a that is connected to the recovery circulating water path R from the heating unit 10 and allows circulating water W to flow through it. It also has an ammonia piping 5b that allows liquid ammonia Al to flow through and ammonia gas Ag to flow through it. The ammonia gas Ag is obtained by vaporizing the liquid ammonia Al through heat exchange with the sensible heat of the circulating water W flowing in the shell 5a.

[0101] In the third embodiment, the recycled circulating water Rw, which is supplied to the heating unit 10 for cooling and then recycled back to the circulating water treatment device 8 and flows in the recycled circulating water path R, is supplied to the ammonia vaporizer 5. It should be noted that a portion of the recycled circulating water Rw recovered from the heating unit 10 may also be branched out and supplied to the ammonia vaporizer 5.

[0102] Furthermore, the heating unit 10 is preferably configured to vaporize liquid ammonia Al using the sensible heat of the recycled circulating water Rw, which cools the conveying device 13 that carries the target material S internally. In the conveying device 13 carrying the target material S, since the circulating water W flows internally, the temperature of the circulating water W used for cooling inside the conveying device 13, which is in direct contact with the high-temperature target material S, easily rises, and even a relatively small amount of circulating water W has a large sensible heat.

[0103] exist Figure 10 In the configuration shown, the circulating water W supplied to the heating unit 10 is recycled as circulating water Rw and connected to the ammonia vaporizer 5 before merging with other recycling circulating water lines R. Therefore, the recycled circulating water Rw is supplied to the ammonia vaporizer 5 without flowing through the long piping of the recycling circulating water line R, thus mitigating the temperature drop of the recycled circulating water Rw before it reaches the ammonia vaporizer 5.

[0104] In the heating section 10, since the constructed machine is exposed to a high-temperature atmosphere, the temperature of the recycled circulating water Rw easily rises as it flows through the heating section 10. For example, when the flow rate of the circulating water W supplied to the heating section 10 is 2100 ton / hr, and all the circulating water W flowing through the heating section 10 flows through the shell 5a of the ammonia vaporizer 5, the sensible heat of the recycled circulating water Rw recovered from the heating section 10 is about 20 to 25 MW. Therefore, even if ammonia Ag is used as fuel gas at about 20% of the combustion device 12 used in the heating section 10, the recycled circulating water Rw flowing through the heating section 10 and through the shell 5a of the ammonia vaporizer 5 has sufficient sensible heat for vaporizing liquid ammonia Al.

[0105] As described above, in the third embodiment, the operating method of the manufacturing apparatus 1 includes the following steps. That is, for the ammonia generation step in the first embodiment, liquid ammonia Al is vaporized by heat exchange with the sensible heat in the circulating water W recovered from the heating unit 10, thereby generating ammonia Ag.

[0106] By means of the manufacturing apparatus 1 and its operation method in this embodiment, liquid ammonia Al can be vaporized through heat exchange with the sensible heat in the circulating water W recovered from the heating unit 10. The resulting ammonia gas Ag is then supplied to the heating unit 10 for heating the target material S. In other words, ammonia gas Ag that suppresses carbon dioxide emissions can be efficiently generated as fuel gas for the heating unit 10. Furthermore, by using the sensible heat of the circulating water W circulating in the manufacturing apparatus 1 to vaporize liquid ammonia Al and use it as fuel gas for the heating unit 10, the additional energy required to convert liquid ammonia Al into fuel gas can be reduced.

[0107] <Fourth Implementation>

[0108] Next, the fourth embodiment of the present invention will be described in detail. Figure 11 The configuration of the circulation path of the circulating water W in the manufacturing equipment 93 of the fourth embodiment is shown in a neutral manner. Figure 11This illustration shows an example of a configuration in which the ammonia vaporizer 5 uses the sensible heat of the recovered circulating water Rw recovered from the target material cooling device 70 before merging with the recovered circulating water Rw recovered from each device of the manufacturing equipment 93 to vaporize liquid ammonia Al. Furthermore, in the fourth embodiment, the configuration is the same as in the first embodiment, except that the ammonia vaporizer 5 is connected to the recovered circulating water path R from the target material cooling device 70.

[0109] That is, in this embodiment, also considering Figure 11 and Figure 6 The configuration shown includes an ammonia vaporizer 5 with a housing 5a that connects to a recovery circulating water path R from the object material cooling device 70 and allows circulating water W to flow through it. It also includes an ammonia piping 5b that allows liquid ammonia Al to flow through and ammonia gas Ag to flow through it. The ammonia gas Ag is obtained by vaporizing the liquid ammonia Al through heat exchange with the sensible heat of the circulating water W flowing in the housing 5a.

[0110] Cooling of the target material S is primarily carried out in the target material cooling device 70, which is equipped with an output roller conveyor, for the purpose of controlling the material properties of the target material S. In particular, considering the purpose of controlling the material properties by quenching the finished steel sheet, such as a high-strength steel sheet, a relatively large amount of circulating water W is supplied. Specifically, in the target material cooling device 70, approximately 6000 to 8000 ton / hr of circulating water W is supplied, and the sensible heat of the recovered circulating water Rw recovered from the target material cooling device 70 is approximately 39 to 52 MW. Therefore, even if ammonia Ag is used as the fuel gas in all the combustion devices 12 used in the heating section 10, the recovered circulating water Rw recovered from the target material cooling device 70 has sufficient sensible heat for vaporizing liquid ammonia Al (approximately 11.3 to 15.0 MW is required in the example described above). Therefore, a recovery circulating water path R, which branches off a portion of the recovered circulating water W from the target material cooling device 70, can be connected to the ammonia vaporizer 5.

[0111] As described above, in the fourth embodiment, the operating method of the manufacturing equipment 1 includes the following steps. That is, for the ammonia generation step in the first embodiment, liquid ammonia Al is vaporized by heat exchange with the sensible heat in the circulating water W recovered from the object material cooling device 70 in the manufacturing line 2, thereby generating ammonia Ag.

[0112] By means of the manufacturing apparatus 1 and its operation method in this embodiment, liquid ammonia Al can be vaporized through heat exchange with the sensible heat in the circulating water W recovered from the target material cooling device 70. The resulting ammonia gas Ag is then supplied to the heating unit 10 for heating the target material S. In other words, ammonia gas Ag that suppresses carbon dioxide emissions can be efficiently generated as fuel gas for the heating unit 10. Furthermore, by using the sensible heat of the circulating water W circulating in the manufacturing apparatus 1 to vaporize liquid ammonia Al and use it as fuel gas for the heating unit 10, the additional energy required to convert liquid ammonia Al into fuel gas can be reduced.

[0113] <Fifth Implementation>

[0114] Next, use Figure 12 The fifth embodiment of the present invention will be described. Figure 12 A schematic diagram of the ammonia vaporizer 9 as a fifth embodiment is shown. Figure 12 (a) is a schematic front view showing the configuration of the ammonia vaporizer 9. Figure 12 (b) is a schematic side view showing the configuration of the ammonia vaporizer 9. Figure 12 The ammonia vaporizer 9 shown is another example of the aforementioned ammonia vaporizer 5.

[0115] Figure 12 An example of an open-rack vaporizer used as a heat exchanger in ammonia vaporizer 9 is shown. An open-rack vaporizer is a type of multi-tube heat exchanger that vaporizes the liquid inside by allowing the liquid on the high-temperature side to flow down the outer surface of a panel with multiple heat transfer tubes arranged thereon.

[0116] The ammonia vaporizer 9 has a panel section 9a, an upper manifold section 9c, a lower manifold section 9d, a water supply section 9e, and a drain section 9f. In the panel section 9a, ammonia arrangement tubes 9b, which serve as multiple heat transfer tubes through which ammonia flows, are arranged in a row and formed into a plate shape. The lower manifold section 9d and the multiple ammonia arrangement tubes 9b constituting the panel section 9a flow through the lower part of the panel section 9a, and liquid ammonia A1 is supplied from the liquid ammonia storage section 4. Pressure is generated inside the lower manifold section 9d by a liquid ammonia pump 7, etc., so that the liquid level of liquid ammonia A1 rises to a certain height inside the ammonia arrangement tubes 9b. The upper manifold section 9c and the multiple ammonia arrangement tubes 9b constituting the panel section 9a flow through the upper part of the panel section 9a, and ammonia gas Ag is recovered from the upper part of the panel section 9a and sent to the ammonia supply section 6. Supply circulating water Pw, which flows in the supply circulating water path P, is supplied to the water supply section 9e in such a way that circulating water W flows down from above the panel section 9a along the surface of the panel section 9a. The drainage section 9f recovers the circulating water W that flows down along the surface of the panel section 9a and supplies it to the recovery circulating water path R as recovered circulating water Rw.

[0117] like Figure 12 As shown, if liquid ammonia Al is supplied to the lower manifold 9d and circulating water W flows down the outer surface of the panel 9a while the liquid level of liquid ammonia Al rises to a certain height inside the ammonia arrangement pipe 9b, heat exchange occurs between the circulating water W and the liquid ammonia Al via the ammonia arrangement pipe 9b, causing the liquid ammonia Al to vaporize and generate ammonia gas Ag. Furthermore, the ammonia gas Ag generated from the vaporization of liquid ammonia Al rises inside the ammonia arrangement pipe 9b and is recovered by the upper manifold 9c.

[0118] That is, also in view of Figure 2 The configuration shown includes an ammonia vaporizer 9 with a water supply section 9e connected to the supply circulation water line P, allowing circulation water W to flow down the outer surface of the panel section 9a, and a drain section 9f connected to the recovery circulation water line R, recovering the circulation water W. It can also be configured to have an ammonia arrangement pipe 9b through which ammonia gas Ag (obtained by vaporizing liquid ammonia Al by raising the water level of liquid ammonia Al and exchanging heat with the sensible heat of the circulation water W flowing down the outer surface of the panel section 9a) flows, and an upper manifold section 9c for recovering the ammonia gas Ag that rises inside the ammonia arrangement pipe 9b.

[0119] Example

[0120] Next, the implementation results of the manufacturing equipment and its operation method according to the present invention applied to a hot rolling line will be described. The hot rolling line of this embodiment has a production capacity of 600 tons / hr. The heating unit 10 has the ability to heat a slab (object material S) at 260°C to 1210°C.

[0121] Conventional heating furnaces (heating sections) use M gas, a type of coal gas, as fuel gas. The lower heating value of the M gas used is 194 MW, and the fuel consumption of the conventional heating furnace is 1.17 GJ / ton. The heating furnace is equipped with a conveying device 13 for internally transporting steel (object material S), and the flow rate of circulating water W flowing inside the conveying device 13 and cooling the conveying device 13 is 2100 m³ / h. 3 / hr. The hot rolling line also uses circulating water W in the material cooling unit 70 with an output roller conveyor, with a flow rate of 7200 m³ / hr. 3 / hr. Additionally, the flow rate of circulating water W used in other machines is approximately 2700 m³ / hr. 3 / hr, as circulating water W, a total of 12000m³ was used. 3 / hr.

[0122] To address this, the heat dissipation of the circulating water W was measured based on the temperature and flow rate of the circulating water W flowing in the supply circulating water path P and the recovery circulating water path R. The results confirmed that the circulating water W flowing in the heating furnace is 20.9 MW, the circulating water W flowing in the target material cooling device 70 is 44.7 MW, and the circulating water W flowing in other machines is 13.7 MW, totaling 79.3 MW of sensible heat. Furthermore, regarding the temperature of the circulating water W, the circulating water W flowing in the heating furnace is 42.5°C, the circulating water W flowing in the target material cooling device 70 is 39.3°C, and the temperature of the circulating water W flowing in other machines after recovery is 38.4°C. Moreover, the average temperature of the circulating water W stored in the sedimentation tank 8a of the circulating water treatment device 8 is 39.7°C. In addition, the circulating water treatment device 8 was regulated to a temperature of 34°C, and the operating rate of the cooling tower 8c of the circulating water treatment device 8 was 87.6%.

[0123] Here, as an example of the invention, the following is described based on Figure 2 The implementation results of the illustrated embodiment (first embodiment). Figure 2 As shown, Example 1 of the invention is a configuration in which the recycling water path R, which recovers all the recycled water Rw flowing in the heating unit 10 and the manufacturing line 2, is connected to an ammonia vaporizer. In this case, the heating unit 10 uses a mixture of ammonia Ag (20% by volume) and M gas (coal gas) (80% by volume) as fuel gas, and uses a combustion device 12 (see [link to invention]). Figure 8 As a result, in the ammonia vaporizer 5, 2.9 MW of the sensible heat of the circulating water W is utilized for the vaporization of liquid ammonia Al, and the temperature of the circulating water W after passing through the ammonia vaporizer 5 decreases by 0.2°C. Therefore, the treatment of the circulating water W in the circulating water treatment unit 8 can be carried out with almost no change from the conventional operating conditions. That is, the operation of the hot rolling line can be carried out with almost the same energy balance as in the conventional case where only M gas is used in the heating furnace, without supplying an additional heat source for the vaporization of liquid ammonia Al. Furthermore, the sensible heat of the circulating water W can be used to efficiently generate ammonia gas Ag, which suppresses the emission of carbon dioxide, as fuel gas for the heating section 10 such as the heating furnace.

[0124] Next, as Example 2 of the invention, the following will be explained based on Figure 9 The implementation results of the illustrated embodiment (second embodiment). Figure 9 As shown, Example 2 of the invention is a configuration in which the supply circulating water path P, which supplies circulating water Pw for cooling the heating unit 10 from the circulating water treatment unit 8, is connected to the ammonia vaporizer 5. In this case, the combustion device 12 of the heating unit 10 uses only ammonia gas (Ag) as fuel gas. Figure 7 The configuration is shown. As a result, the heat required to vaporize liquid ammonia Al in the ammonia vaporizer 5 is 14.7 MW, and the temperature of the circulating water W flowing in the ammonia vaporizer 5 decreases by 6.0 °C. Therefore, the temperature of the circulating water W flowing inside the conveying device 13 of the heating section 10 decreases, thus increasing the heat required to heat the target material S inside the heating section 10. Therefore, although the fuel consumption of the heating section 10 increases to 1.18 GJ / ton, the increase is slight. Furthermore, the temperature of the circulating water W recovered from the heating section 10 decreases during the supply phase to the heating section 10, so the temperature of the circulating water W recovered from the sedimentation tank 8a of the circulating water treatment device 8 is 38.8 °C, which is lower than the conventional circulating water temperature. As a result, the operating rate of the cooling tower 8c of the circulating water treatment device 8 is 78.8%, which is lower than the conventional rate, and the power consumed in cooling the circulating water W can be reduced. Furthermore, the sensible heat of circulating water W with heat can efficiently generate ammonia gas Ag, which can suppress the emission of carbon dioxide, as fuel gas for heating units 10 such as heaters.

[0125] Next, as Example 3 of the invention, the following will be explained based on Figure 10 The implementation results of the illustrated embodiment (the third embodiment). Figure 10 As shown, Example 3 of the invention connects a recovery circulating water path R through which recovered circulating water Rw recovered from the heating unit 10 flows to an ammonia vaporizer 5. That is, Example 3 of the invention uses the sensible heat of the circulating water W recovered from the heating unit 10 and recovered circulating water Rw recovered from other equipment besides the heating unit 10 of the manufacturing equipment 1 before merging to vaporize liquid ammonia Al. Specifically, the ammonia vaporizer 5 is configured to allow the circulation water W used for cooling the conveying device 13 to flow through, and is connected to the recovery circulating water path R provided inside the conveying device 13. In this case, the combustion device 12 of the heating unit 10 uses only ammonia Ag as fuel gas. Figure 7 The configuration is shown. As a result, the temperature of the recovered circulating water Rw after flowing through the ammonia vaporizer 5 decreases by 6.0°C compared to before flowing through the ammonia vaporizer 5, reaching 36.5°C. Consequently, the temperature of the circulating water W recovered from the sedimentation tank 8a of the circulating water treatment device 8 becomes 38.6°C, which is lower than the temperature of the circulating water in the past. As a result, the operating rate of the cooling tower 8c of the circulating water treatment device 8 becomes 77.6%, which is lower than in the past, and the power consumed in cooling the circulating water W can be reduced. Furthermore, the sensible heat of the circulating water W can be used to efficiently generate ammonia gas Ag, which suppresses the emission of carbon dioxide, as fuel gas for the heating section 10 such as the heater.

[0126] Explanation of reference numerals in the attached figures

[0127] 1 Manufacturing equipment

[0128] 2 manufacturing lines

[0129] 3 Ammonia generation device

[0130] 4. Liquid Ammonia Storage Section

[0131] 5. Ammonia vaporizer

[0132] 6. Ammonia Supply Department

[0133] 7. Liquid ammonia pump

[0134] 8. Circulating water treatment device

[0135] 10 Heating section

[0136] 11 Loading section

[0137] 12 Combustion device

[0138] 13 Conveying device

[0139] 14 Extraction Section

[0140] 15. Flue Section

[0141] 20 Descaling device

[0142] 30. Width Reduction Pressing Device

[0143] 40 Roughing Rolling Unit

[0144] 50 Fine-finishing descaling device

[0145] 60 Finishing Rolling Unit

[0146] 70 Object material cooling device

[0147] 80 winding machine

[0148] D Conveying direction

[0149] S object material

[0150] F Burning Flame

[0151] O Combustion air

[0152] Al liquid ammonia

[0153] Ag ammonia

[0154] Cg gas

[0155] ACg Coal-ammonia mixture

[0156] P supplies circulating water circuit

[0157] R Recycling Water Circuit

[0158] W Circulating Water

[0159] Pw supplies circulating water

[0160] Rw Recycles Circulating Water

Claims

1. Manufacturing equipment comprising: a heating section for heating a target material; a manufacturing line for processing the target material heated by the heating section; a circulating water treatment device for treating circulating water used for cooling in the heating section and the manufacturing line; a supply circulating water path for supplying the circulating water from the circulating water treatment device to the heating section and the manufacturing line; a recovery circulating water path for recovering the circulating water from the heating section and the manufacturing line to the circulating water treatment device; and an ammonia generating device for supplying ammonia gas for combustion to the heating section, wherein... The ammonia generating apparatus includes: a liquid ammonia storage unit for storing ammonia in a liquid state; an ammonia vaporizer for vaporizing liquid ammonia supplied from the liquid ammonia storage unit through heat exchange with sensible heat in the circulating water; and an ammonia supply unit for supplying ammonia obtained through heat exchange in the ammonia vaporizer to the heating unit.

2. The manufacturing equipment as described in claim 1, wherein, The ammonia vaporizer includes: a shell connected to the recovery circulating water circuit and allowing the circulating water to flow through; and ammonia piping that allows the liquid ammonia to flow through and vaporizes the liquid ammonia through heat exchange with the sensible heat of the circulating water flowing in the shell.

3. The manufacturing equipment as described in claim 1, wherein, The ammonia vaporizer includes: a shell connected to the supply circulating water path and allowing the circulating water to flow through; and an ammonia piping that allows the liquid ammonia to flow through and vaporizes the liquid ammonia through heat exchange with the sensible heat of the circulating water flowing in the shell.

4. The manufacturing equipment as described in claim 1, wherein, The ammonia vaporizer includes: a shell connected to the recovery circulating water path from the heating section and through which the circulating water flows; and an ammonia piping through which the liquid ammonia flows and through which the liquid ammonia is vaporized by heat exchange with the sensible heat of the circulating water flowing in the shell.

5. The manufacturing equipment as described in any one of claims 1 to 4, wherein, The heating section has a conveying device that has the recycling water path inside and conveys the object material.

6. The manufacturing equipment as described in any one of claims 1 to 5, wherein, The manufacturing line includes an object material cooling device that uses the circulating water to cool the object material and recovers the circulating water used in cooling the object material and allows it to flow back into the recovery circulating water path.

7. The manufacturing equipment as described in claim 6, wherein, The ammonia vaporizer has: A shell that connects to and allows the circulating water from the cooling device for the object material to flow through; and Ammonia piping, which allows the flow of liquid ammonia and ammonia gas obtained by vaporizing the liquid ammonia through heat exchange with the sensible heat of the circulating water flowing in the shell.

8. The manufacturing equipment as described in any one of claims 1 to 7, wherein, In order to mix with the ammonia supplied from the ammonia supply section, the heating section has a gas supply section for supplying coal gas.

9. Operating methods for manufacturing equipment, including, While supplying and recycling circulating water for cooling to the heating section that heats the target material and the manufacturing line that processes the target material, ammonia gas for combustion is supplied from the ammonia generation unit to the heating section, and manufacturing is carried out using manufacturing equipment having the heating section and the manufacturing line. The operation method has the following characteristics: In the liquid ammonia supply step, liquid ammonia is supplied from the liquid ammonia storage section to the ammonia vaporizer in the ammonia generating device; In the ammonia generation step, the liquid ammonia is vaporized in the ammonia vaporizer by heat exchange with the sensible heat of the circulating water, thereby generating ammonia gas. and The ammonia supply step involves supplying the generated ammonia gas to the heating unit.

10. The method of operating the manufacturing equipment as described in claim 9, wherein, In the ammonia generation step, the liquid ammonia is vaporized by heat exchange with the sensible heat in the circulating water recovered from the heating unit and the manufacturing line, thereby generating ammonia.

11. The method of operating the manufacturing equipment as described in claim 9, wherein, In the ammonia generation step, the liquid ammonia is vaporized by heat exchange with the sensible heat in the circulating water supplied to the heating unit and the manufacturing line, thereby generating ammonia.

12. The method of operating the manufacturing equipment as described in claim 9, wherein, In the ammonia generation step, the liquid ammonia is vaporized by heat exchange with the sensible heat in the circulating water recovered from the heating section, thereby generating ammonia.

13. The method of operating the manufacturing equipment as described in claim 9, wherein, In the ammonia generation step, the liquid ammonia is vaporized by heat exchange with the sensible heat in the circulating water recovered from the object material cooling device in the manufacturing line, thereby generating ammonia.

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