Apparatus for the use of liquefied flammable gas, method for the use of liquefied flammable gas, and cement manufacturing equipment.

Abstract

To provide a use device of a liquefied combustible gas capable of easily and inexpensively gasifying a liquefied combustible gas especially in a cement production facility.SOLUTION: There is provided a use device of a liquefied combustible gas comprising a combustible gas pipeline which communicates: a tank which is attached to a cement production facility comprising a calcination furnace, a cement kiln, and a clinker cooler coupled to a part in front of a furnace of the cement kiln, and stores the liquefied combustible gas in a liquid state; and a blowing part which is set on at least one position belonging to a group formed of a part in front of the furnace of the cement kiln, a tail part of the furnace of the cement kiln, and the calcination furnace, through one or both of the clinker cooler, and inside of a gas extraction pipeline in which the extraction gas extracted from the clinker cooler circulates. The combustible gas pipeline gasifies the liquefied combustible gas in the liquid state during circulation in the combustible gas pipeline, and then, supplies the combustible gas obtained by gasifying the liquefied combustible gas to the blowing part.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an apparatus for utilizing liquefied combustible gas, and particularly to an apparatus for utilizing liquefied combustible gas configured to be attached to cement manufacturing equipment. Further, the present invention relates to a method for utilizing liquefied combustible gas, and particularly to a method for utilizing liquefied combustible gas that can be used in the cement manufacturing process. Further, the present invention relates to cement manufacturing equipment capable of utilizing liquefied combustible gas.

Background Art

[0002] In the production of cement, it is known that a large amount of CO2 is emitted. The reasons for this are as follows. The first reason is that in the cement production process, it is necessary to bake cement raw materials at a high temperature in a furnace, and a large amount of fossil fuel is used to obtain the combustion energy. The second reason is that limestone, which is the main raw material of cement, causes a decarbonation reaction (CaCO3 → CaO + CO2).

[0003] CO2 is a type of greenhouse gas and has a great impact on global warming. Therefore, it is required to reduce the CO2 emissions in cement manufacturing plants as well.

[0004] Under such a background, recently, in the production of cement, it has been considered to use a combustible gas fuel with a lower CO2 emission per unit than coal, which is the conventional main fuel.

[0005] For example, in Patent Document 1 below, it is proposed to use ammonia as an auxiliary fuel together with fossil fuel, which is the conventional main fuel, as a fuel during cement production.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] In order to use flammable gases such as ammonia as fuel in cement production, it is necessary to introduce the flammable gas into the cement manufacturing plant. Two methods are possible for this. The first method involves constructing a gas pipeline connecting the facilities of the flammable gas supplier to the cement manufacturing plant, and supplying the flammable gas to the cement manufacturing plant in gaseous form through this pipeline. The second method involves liquefying the flammable gas at the supplier's site, transporting tanks filled with the liquefied flammable gas to the cement manufacturing plant by land or sea, and then vaporizing it at the cement manufacturing plant for use. The first method has many problems in terms of both initial and running costs, so the second method is considered more feasible.

[0008] If the second method is adopted, as mentioned above, the liquefied flammable gas needs to be vaporized at the cement manufacturing plant. A commonly known method for vaporizing liquefied ammonia is to use a vaporizer with hot water or steam heated by a heater. However, this method requires adding thermal energy to the liquefied ammonia, including the sensible heat needed to raise the water temperature from ambient temperature to hot water temperature (generally around 40°C) and the latent heat of vaporization of the liquefied ammonia. Considering that liquefied ammonia is used as part of the fuel for cement manufacturing, the initial cost of introducing the equipment to supply the above thermal energy, as well as the running costs during actual operation, are expected to be substantial.

[0009] Such cost issues hinder the use of liquefied flammable gas as an alternative fuel in cement production, making it difficult to reduce CO2 emissions during cement manufacturing. Patent document 1 mentioned above makes no mention whatsoever of the above issues that may arise when liquefied flammable gas is actually used in cement manufacturing plants, nor of any countermeasures to these issues.

[0010] In view of these problems, the present invention aims to provide a device for utilizing liquefied flammable gas and a method for utilizing liquefied flammable gas that enable the vaporization of liquefied flammable gas in a simple and inexpensive manner, particularly in cement manufacturing plants. Furthermore, the present invention aims to provide cement manufacturing equipment that can vaporize and utilize liquefied flammable gas in a simple and inexpensive manner. [Means for solving the problem]

[0011] The present invention relates to a liquefied flammable gas utilization device, which can be attached to a cement manufacturing facility having a calcination furnace for calcining cement raw materials, a cement kiln for firing the cement raw materials calcined in the calcination furnace to produce clinker, and a clinker cooler connected to the front of the cement kiln. The system includes a tank in which the liquefied flammable gas is stored in a liquid state, and one or more injection points set in the group consisting of the front of the cement kiln, the rear of the cement kiln, and the calcination furnace, connected via either or both of the clinker cooler and the extraction piping through which the extracted gas extracted from the clinker cooler flows. The flammable gas piping is characterized by vaporizing the liquefied flammable gas during flow, and then supplying the resulting flammable gas to the injection point.

[0012] Clinker coolers installed in cement manufacturing facilities receive and cool cement clinker (hereinafter abbreviated as "clinker" as appropriate) fired in the cement kiln. Clinker coolers typically cool clinker by blowing in ambient air and exchanging heat with the clinker, which is at over 1000°C (typically around 1350°C). Therefore, there is air (atmospheric gas) inside the clinker cooler whose temperature has risen due to heat exchange with the high-temperature clinker.

[0013] A portion of this high-temperature atmospheric gas is extracted through extraction piping. Depending on the temperature, the extracted gas (hereinafter referred to as "extracted gas") is either sent to a calcination furnace and used as combustion air in the calcination furnace, or sent to the raw material process and used for drying the raw materials. In addition, a portion of the atmosphere at lower temperatures is released as exhaust gas.

[0014] According to the above configuration, the piping through which the liquefied flammable gas flows (flammable gas piping) is arranged to pass through either the clinker cooler or the extraction piping through which the extracted gas extracted from the clinker cooler flows, or both. In other words, the flammable gas piping is arranged to pass through a region where a high-temperature atmosphere exists (hereinafter referred to as the "high-temperature region"). Therefore, as the liquefied flammable gas flows through the flammable gas piping, it passes through the region where a high-temperature atmosphere exists, undergoing heat exchange through the piping and vaporizing. The high-temperature region can be, for example, a region within the range of 150°C to 1000°C.

[0015] The flammable gas piping, after passing through the high-temperature region described above, leads to one or more injection points located in a group consisting of the front of the cement kiln, the rear of the cement kiln, and the calcination furnace. In other words, liquefied flammable gas, stored in a tank in a liquid state, is sent into the flammable gas piping, vaporizes as it flows through the piping, and is then injected as gaseous flammable gas into the injection points. This allows the flammable gas to be used as an alternative fuel to the main fuel (typically coal) in the cement kiln or calcination furnace.

[0016] According to the above configuration, by arranging the piping for flammable gas to reach the injection point via the high-temperature region mentioned above, it becomes possible to vaporize and utilize liquefied flammable gas at the cement manufacturing plant. This allows for a simple and inexpensive method of vaporizing liquefied flammable gas into flammable gas. As a result, flammable gas can be easily used as an alternative fuel in the cement manufacturing process, which is expected to contribute to reducing CO2 emissions.

[0017] When piping for flammable gases is routed through extraction piping through which extracted gas extracted from a clinker cooler flows, this extraction piping can include, as mentioned above, piping leading to the calcination furnace (extraction piping for the calcination furnace), piping leading to the raw material process (extraction piping for raw material drying), and piping leading to the exhaust system such as a chimney (extraction piping for exhaust gas). Among these, it is particularly preferable to provide the flammable gas piping so that it passes through the exhaust gas extraction piping. The reason for this is that if it passes through other extraction piping, heat exchange with the flammable gas piping through which liquefied flammable gas flows in a liquid state will lower the temperature of the extracted gas flowing through the extraction piping, and it is expected that the usable temperature when used as combustion air for the calcination furnace or as air for drying raw materials will decrease. On the other hand, when flammable gas piping passes through exhaust gas piping, the extracted gas flowing through the exhaust gas extraction piping is originally intended to be discharged outside the system. Therefore, even if the temperature drops, it does not affect the overall thermal efficiency, and furthermore, waste heat can be utilized.

[0018] However, even if flammable gas piping passes through the extraction piping for the calcination furnace or the extraction piping for drying raw materials, the temperature drop of the extracted gas flowing through these pipes is minimal, and at least no additional heating equipment is required. Therefore, even if these extracted gases are used as combustion air for the calcination furnace or as drying air for raw materials, the thermal efficiency does not decrease significantly compared to using extracted gas without heat exchange.

[0019] Flammable gases (and their liquefied form, liquefied flammable gas) will not ignite regardless of temperature if they are of high purity. In the case of ammonia, the flammability range is considered to be 15.5% to 27% by volume, and if the purity exceeds, for example, 80% by volume, spontaneous combustion will not occur. Even for hydrogen, one of the most easily flammable gases, the maximum value of the flammability range is considered to be 75% by volume. Therefore, regardless of the temperature range through which the flammable gas piping passes within the clinker cooler or extraction piping, it is unlikely that the flammable gas will spontaneously ignite while flowing through the piping.

[0020] When supplying liquefied flammable gas from a tank to a flammable gas pipeline, a liquid transfer pump may be used. On the other hand, the flammable gas pipeline does not need to be equipped with a blower to promote the flow of gaseous flammable gas. The expansion pressure generated when the liquefied flammable gas vaporizes during flow can act as a facilitating force for the flow of gaseous flammable gas through the flammable gas pipeline.

[0021] The liquefied flammable gas may contain 70% by volume or more of one or more gases belonging to the group consisting of ammonia, methane, ethane, propane, and butane. Preferably, the liquefied flammable gas contains 70% by volume or more of ammonia.

[0022] The ambient temperature of the clinker cooler connected to the front of the cement kiln decreases as the area within the clinker cooler moves away from the front of the kiln, in other words, as the clinker cools. Therefore, if flammable gas piping is routed to pass through the clinker cooler, the ambient temperature, or in other words, the degree of heat exchange, will differ depending on where the flammable gas piping passes through the clinker cooler.

[0023] Therefore, the flammable gas piping may be configured to pass through multiple regions with different ambient temperatures within the clinker cooler, and may be equipped with multiple valves to control the flow rate through each region.

[0024] As a specific example, a combustible gas pipe is installed so as to pass through a first region where the ambient temperature in the clinker cooler is in the range of 150°C to 300°C, a second region where the ambient temperature is in the range of 250°C to 650°C, and a third region where the ambient temperature is in the range of 600°C to 900°C, respectively. And a valve for controlling the flow rate passing through each region is provided in the combustible gas pipe. By adjusting the valve, the flow rate of the liquefied combustible gas passing through each region is controlled. Thereby, the temperature of the combustible gas at the time of being supplied to the injection location is controlled.

[0025] Typically, it is as follows. A part of the atmosphere in the third region is extracted through the exhaust pipe for the calciner and sent to the calciner. A part of the atmosphere in the second region is extracted through the exhaust pipe for raw material drying and sent to the raw material process. A part of the atmosphere in the first region is extracted through the exhaust pipe for exhaust gas and discharged to the atmosphere through a chimney or the like.

[0026] The utilization device of the liquefied combustible gas is provided at the end of the combustible gas pipe on the side of the injection location, and includes a burner for injecting the liquefied combustible gas into the injection location. It includes a primary air pipe that allows primary air to flow in and is connected to the combustible gas pipe at a position upstream of the burner via one or both of the inside of the clinker cooler and the exhaust pipe. The combustible gas pipe may be configured to guide a mixed gas in which the combustible gas and the primary air are mixed to the burner at a position downstream of the connection point with the primary air pipe.

[0027] According to the above configuration, the flammable gas, which has vaporized while flowing through the flammable gas piping and become a gaseous state, is injected from the injection point in a state where it has merged with the primary air flowing through the primary air piping. At this time, since the primary air piping is provided so as to pass through either or both the clinker cooler and / or the extraction piping, the primary air flowing through the primary air piping is heated before it merges with the flammable gas. As a result, the flammable gas is injected from the injection point in a state where it is further preheated, further improving the flammability at the injection point.

[0028] In this case, the concentration of flammable gas in the flammable gas piping decreases after the point where the primary air piping and the flammable gas piping merge. As a result, depending on the flow rate of the primary air, the concentration of flammable gas may fall within the flammable range. If this situation occurs, the mixture of flammable gas and primary air flowing through the flammable gas piping may ignite, potentially damaging the piping.

[0029] Therefore, it is preferable that the temperature of the mixed gas be adjusted at the junction of the primary air piping and the combustible gas piping so that the combustible gas in gaseous state is below its ignition point temperature. This can be achieved by designing the combustible gas piping to pass only through the first region, for example. Another way to adjust the temperature is to design the combustible gas piping to pass through multiple regions (two or more of the first, second, and third regions) and adjust the flow rate of the combustible gas passing through each region using valves or the like. Alternatively, the temperature and flow rate of the primary air may also be adjusted.

[0030] Furthermore, the flow rate of the primary air and the flow rate of the (liquefied) flammable gas may be adjusted so that the concentration of flammable gas in the mixed gas does not fall within the combustion range. In this case, the flammable gas may exceed its ignition point temperature at the junction of the primary air piping and the flammable gas piping. The concentration of flammable gas in the mixed gas can be adjusted by adjusting the flow rate of the primary air flowing through the primary air piping with a valve, or by adjusting the flow rate of the liquid flammable gas supplied to the flammable gas piping with a liquid supply pump.

[0031] The aforementioned apparatus for utilizing liquefied flammable gas is A burner having multiple ports and attached to the end of the flammable gas piping on the injection point side, which injects the flammable gas into the injection point through one or more of the ports, The system may also include primary air piping through which primary air flows, and which, via either or both the clinker cooler and the extraction piping, connects to a port among the multiple ports of the burner that is different from the port to which the flammable gas piping is connected.

[0032] In the above configuration, the primary air flowing through the primary air piping is heated before being sent to the burner. From the burner, a flammable gas in gaseous form is blown in together with the heated primary air from the injection point, further improving the flammability at the injection point.

[0033] In this configuration, the heated primary air and the flammable gas are not mixed within the piping. Therefore, even without adjusting the temperature or flow rate of the flammable gas, the possibility of the flammable gas igniting while flowing through the piping is extremely low.

[0034] The primary air flowing through the primary air piping may be ambient air, the atmospheric gas in the clinker cooler, or the extracted gas in the extraction piping.

[0035] When using the atmospheric gas in the clinker cooler or the extracted gas in the extraction piping as the primary air, these gases mainly contain scattered dust derived from clinker. Since combustible gases contain almost no ash, their radiant heat transfer during combustion is lower compared to coal, which is the main fuel. However, as described above, by blowing primary air containing scattered dust together with the combustible gas from the injection point, the scattered dust acts as a radiant heat transfer medium during the combustion of the combustible gas, thus contributing to the stabilization of the combustion of the combustible gas.

[0036] On the other hand, when using the atmospheric gas in the clinker cooler or the extracted gas in the extraction piping as the primary air, it is conceivable that the primary air flow rate may change over time due to thinning of the primary air piping by scattered dust in some locations, or due to scattered dust adhering to the pipe walls of the primary air piping. From this viewpoint, a dust collector for collecting scattered dust may be provided in the primary air piping. That is, the primary air piping may be equipped with a primary air blower that promotes the flow of one or both of the atmospheric gas in the clinker cooler and the extracted gas in the extraction piping, and a dust collector that collects scattered dust contained in the gas flowing through the primary air piping.

[0037] The scattered dust collected by the dust collector can be mixed with clinker discharged from a clinker cooler, for example, or mixed with cement in the finishing process of cement manufacturing where gypsum or other materials are added. This is expected to have the effect of reducing the cost of crushing clinker.

[0038] The present invention relates to a method for utilizing liquefied flammable gas in a cement manufacturing process that involves firing cement raw materials to produce a cement kiln. A step of supplying liquefied flammable gas to a flammable gas pipe arranged so as to pass through either or both the clinker cooler and the extraction pipe through which the extracted gas extracted from the clinker cooler flows, The invention is characterized by comprising the steps of vaporizing the liquefied flammable gas in a liquid state while it is flowing through a piping for flammable gas, and then blowing the flammable gas obtained from the vaporization of the liquefied flammable gas into one or more blowing locations set in the group consisting of the front of the clinker cooler, the rear of the clinker cooler, and the calcination furnace.

[0039] Furthermore, the cement manufacturing equipment according to the present invention is A calcination furnace for calcining cement raw materials, A cement kiln that fires the cement raw materials that have been calcined in the calcination furnace to produce clinker, A clinker cooler connected to the front of the cement kiln, The system comprises a tank for storing liquefied flammable gas and flammable gas piping that connects one or more injection points, which are set in the group consisting of the front of the clinker cooler, the rear of the clinker cooler, and the calcination furnace, via the inside of the clinker cooler or through extraction piping through which extracted gas extracted from the clinker cooler flows. The flammable gas piping is characterized in that, after vaporizing the liquefied flammable gas in a liquid state while it is flowing through the flammable gas piping, the flammable gas obtained from the vaporization of the liquefied flammable gas is supplied to the injection point. [Effects of the Invention]

[0040] According to the present invention, liquefied flammable gas can be vaporized and utilized in a cement manufacturing plant in a simple and inexpensive manner. [Brief explanation of the drawing]

[0041] [Figure 1] This is a conceptual diagram schematically showing an example of the configuration of the cement manufacturing equipment according to the first embodiment. [Figure 2] This is a schematic diagram showing a portion of the cement manufacturing equipment shown in Figure 1. [Figure 3] This diagram schematically shows a portion of the cement manufacturing equipment shown in Figure 1, and corresponds to a conceptual diagram schematically illustrating an example of the configuration of the liquefied flammable gas utilization device in the first embodiment. [Figure 4] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the first embodiment. [Figure 5] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the first embodiment. [Figure 6] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the first embodiment. [Figure 7] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the first embodiment. [Figure 8] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the first embodiment. [Figure 9] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the first embodiment. [Figure 10] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the first embodiment. [Figure 11] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the first embodiment. [Figure 12] This diagram schematically shows an example configuration of a liquefied flammable gas utilization device according to the second embodiment. [Figure 13] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device according to the second embodiment. [Figure 14] This diagram schematically shows an example configuration of a liquefied flammable gas utilization device according to the third embodiment. [Figure 15] This diagram schematically shows an example configuration of a liquefied flammable gas utilization device according to the fourth embodiment. [Figure 16] This diagram schematically shows another configuration example of the liquefied flammable gas utilization device of the fourth embodiment. [Modes for carrying out the invention]

[0042] The liquefied flammable gas utilization apparatus according to the present invention is an apparatus that can be attached to a cement manufacturing facility that produces cement clinker (hereinafter abbreviated as "clinker") from cement raw materials. Hereinafter, embodiments of the liquefied flammable gas utilization apparatus, the method of utilizing the liquefied flammable gas, and the cement manufacturing facility according to the present invention will be described with reference to the drawings. Note that the following drawings are schematic representations, and the dimensional ratios shown in the drawings do not necessarily correspond to the actual dimensional ratios. Furthermore, the dimensional ratios do not necessarily coincide between the drawings.

[0043] In the following diagrams, the flow of a fluid (gas or liquid) is schematically represented by a dashed line.

[0044] [First Embodiment] Figure 1 is a schematic conceptual diagram showing the structure of a cement manufacturing facility according to the first embodiment. The cement manufacturing facility 1 includes a preheater 11 for preheating the cement raw material M1, a calcination furnace 13 for calcining the cement raw material M1, a cement kiln 20 for firing the cement raw material M1 calcined in the calcination furnace 13 to produce clinker 3, and a clinker cooler 30 connected to the front part 20b of the cement kiln 20 for cooling the produced clinker 3. As shown in Figure 1, the calcination furnace 13 is connected to the rear part 20a of the cement kiln 20.

[0045] Primary air 25 is blown into the cement kiln 20 from the main burner 21 located on the front 20b side of the kiln (see Figure 2). In this embodiment, the cement manufacturing equipment 1 is equipped with a flammable gas burner 55 on the front 20b side of the kiln, separate from the main burner 21. This flammable gas burner 55 is connected to a tank 51 in which liquefied flammable gas 50a is stored in a liquid state via a flammable gas piping 53. A liquid transfer pump 52 is provided in the flammable gas piping 53, and the liquefied flammable gas 50a stored in the tank 51 is sent to the flammable gas piping 53 by the pressure of the liquid transfer pump 52. However, the liquid transfer pump 52 is not an essential element in this invention, as long as the configuration allows the liquefied flammable gas 50a stored in the tank 51 to be sent to the flammable gas piping 53.

[0046] The liquefied flammable gas 50a can be a gas containing 70% or more by volume of one or more gases belonging to the group consisting of ammonia, methane, ethane, propane, and butane. Typically, the liquefied flammable gas 50a is liquefied ammonia, liquefied methane (liquefied natural gas), liquefied propane (liquefied petroleum gas), or liquefied butane, with liquefied ammonia being the most typical.

[0047] The flammable gas piping 53 is arranged so that a portion of it passes through a region where a high-temperature atmosphere exists (high-temperature region). Therefore, the liquefied flammable gas 50a, in a liquid state, is vaporized by heat exchange through the pipe wall of the flammable gas piping 53 as it flows through the flammable gas piping 53, becoming flammable gas 50b in a gaseous state. This gaseous flammable gas 50b is supplied to the flammable gas burner 55. When the liquefied flammable gas 50a is vaporized, the flammable gas piping 53 is cooled by latent heat, but since high-temperature hot air that has cooled the clinker 3 is always supplied to the high-temperature region, the heat source is not lost.

[0048] In the following, the liquefied flammable gas 50a in its liquid state before vaporization will be simply referred to as "liquefied flammable gas 50a," and the gas after the liquefied flammable gas 50a has vaporized will be referred to as "flammable gas 50b."

[0049] In this embodiment, the flammable gas piping 53 is arranged so that a portion of it passes through the clinker cooler 30. In other words, the region inside the clinker cooler 30 is the high-temperature region described above. This point will be described in detail later.

[0050] The powdered raw material M1 supplied to the top of the preheater 11 flows downwards. As the raw material M1 moves through the preheater 11, it is preheated by high-temperature exhaust gas and sent to the calcination furnace 13. The calcination furnace 13 is equipped with a calcination furnace burner 14 that uses pulverized coal or the like as its main fuel. Inside the calcination furnace 13, the raw material M1 is further preheated (calcined) by the calcination furnace burner 14 and high-temperature gas from the cement kiln 20, and the CaCO3, the main component of limestone contained in the raw material M1, is thermally decomposed (decarboxylated) into CaO and CO2. The temperature of the powdered raw material M1 reaches approximately 750°C to 800°C.

[0051] The raw material M1, which has been calcined in the calcination furnace 13, enters the cement kiln 20 from the kiln tail 20a side and moves while rolling towards the outlet on the kiln front 20b side. The main burner 21 and the combustible gas burner 55 are installed on the kiln front 20b side. The main burner 21 supplies the main fuel, such as pulverized coal, and the primary air 25 for calcination to the cement kiln 20. The combustible gas burner 55 blows combustible gas 50b, which has been sent from the combustible gas piping 53, into the cement kiln 20 from the kiln front 20b side. In other words, in this embodiment, the kiln front 20b of the cement kiln 20 corresponds to the blowing point of the combustible gas 50b.

[0052] With this configuration, the combustible gas 50b supplied from the combustible gas burner 55 can be used as fuel for firing the raw material M1 in the cement kiln 20, along with the main fuel such as pulverized coal supplied from the main burner 21. In other words, this cement manufacturing facility 1 can reduce the amount of fuel mainly consisting of coal, and since combustible gas 50b, which has a lower CO2 emission intensity than coal, can be used as fuel, a reduction in CO2 emissions during cement manufacturing can be expected.

[0053] Inside the cement kiln 20, the raw material M1 is heated to approximately 1450°C to 1500°C to produce clinker 3. After the temperature of this clinker 3 decreases to approximately 1300°C to 1350°C, it is discharged into the clinker cooler 30.

[0054] The clinker cooler 30 cools the clinker 3 with ambient temperature air CA (approximately 20°C to 30°C) supplied by a cooling fan (not shown). Typically, multiple plates are laid on the bottom surface of the clinker cooler 30 so as to be movable in the front-to-back direction. The front-to-back movement of the plates guides the clinker 3 downstream (towards the outlet of the clinker cooler 30). As the clinker 3 approaches the outlet of the clinker cooler 30, its temperature decreases, and it is then discharged from the outlet and stored in a clinker silo (not shown).

[0055] Inside the clinker cooler 30, the cooling air CA exchanges heat with the high-temperature clinker 3. As a result, high-temperature air is generated inside the clinker cooler 30. A portion of this high-temperature air is sent from the front of the kiln 20b into the cement kiln 20 and used as secondary air for combustion.

[0056] Figure 2 is a schematic diagram showing a portion of the cement manufacturing equipment 1 in Figure 1. As described above, the temperature of the clinker 3 decreases as you move downstream within the clinker cooler 30. Therefore, the temperature of the atmospheric gas inside the clinker cooler 30 also decreases as you move downstream. Typically, the internal space of the clinker cooler 30 has a first region 31 where the ambient temperature is in the range of 150°C to 300°C, a second region 32 where the ambient temperature is in the range of 250°C to 650°C, and a third region 33 where the ambient temperature is in the range of 600°C to 900°C. Of the first region 31, the second region 32, and the third region 33, the first region 31 is closest to the outlet end of the clinker cooler 30, and the third region 33 is closest to the cement kiln 20.

[0057] Because the atmospheric gas in the clinker cooler 30 has a temperature distribution, it is sent to different locations for use depending on the temperature, taking into consideration thermal efficiency. In the example in Figure 2, a portion of the atmospheric gas in the third region 33 of the clinker cooler 30 is extracted through the extraction piping 43 for the calcination furnace and sent to the calcination furnace 13, where it is used as part of the combustion air (see also Figure 1). A portion of the atmospheric gas in the second region 32 of the clinker cooler 30 is extracted through the extraction piping 42 for raw material drying and sent to the raw material process, where it is used for drying the raw material M1 (see also Figure 1). On the other hand, the atmospheric gas in the first region 31 of the clinker cooler 30 has a temperature in the range of 150°C to 300°C, and therefore has low utility value from the viewpoint of thermal efficiency, etc., so it is extracted through the extraction piping 41 for exhaust gas and then discharged into the atmosphere through a chimney, etc. (see also Figure 1).

[0058] Figure 3 is a schematic diagram showing a portion of the cement manufacturing facility 1 in Figure 1, and is displayed in the same manner as in Figure 2. However, for illustrative purposes, the illustration of each extraction pipe (41, 42, 43) that was shown in Figure 2 has been omitted.

[0059] In this embodiment, the flammable gas piping 53 is arranged to pass through the first region 31 of the clinker cooler 30. As described above, the first region 31 of the clinker cooler 30 has an ambient temperature in the range of 150°C to 300°C, corresponding to a high-temperature region. The liquefied flammable gas 50a, supplied from the tank 51 via the liquid transfer pump 52, passes through the high-temperature region 53a as it flows through the flammable gas piping 53. Within this high-temperature region 53a, heat exchange occurs between the high-temperature atmosphere in the first region 31 and the pipe wall of the flammable gas piping 53, causing the liquefied flammable gas 50a flowing through the flammable gas piping 53 to be heated and vaporized (becoming flammable gas 50b).

[0060] Therefore, after passing through the high-temperature region 53a, the vaporized flammable gas 50b flows through the flammable gas piping 53 and is supplied to the flammable gas burner 55. Furthermore, the vaporization of the liquefied flammable gas 50a while flowing through the high-temperature region 53a generates expansion pressure, which can act as a facilitating force for the gaseous flammable gas 50b as it flows through the flammable gas piping 53. For this reason, a mechanism for blowing gaseous flammable gas 50b is not necessarily required in the flammable gas piping 53.

[0061] According to the configuration shown in Figure 3, by arranging the flammable gas piping 53 so that it reaches the injection point of the flammable gas 50b (in this case, the front of the kiln 20b) via the high-temperature region 53a (in this case, the first region 31 of the clinker cooler 30), the liquefied flammable gas 50a can be vaporized and used in the cement manufacturing facility 1. Therefore, the liquefied flammable gas 50a can be vaporized in the cement manufacturing facility 1 in a simple and inexpensive manner.

[0062] When installing flammable gas piping 53 inside the clinker cooler 30, it is preferable to install it in a location with a high vertical height, such as near the ceiling or an inner wall, so as not to obstruct the airflow of the atmosphere inside the clinker cooler 30. However, the present invention does not limit the location inside the clinker cooler 30 where the flammable gas piping 53 is installed.

[0063] As described above, the portion of the flammable gas piping 53 that passes through the clinker cooler 30 is intended to exchange heat with the atmospheric gas (high-temperature air) inside the clinker cooler 30. From this perspective, the shape of the flammable gas piping 53 installed in this region may be appropriately processed to increase its surface area. The shape can be arbitrary, and examples include a spiral shape, an uneven shape, etc.

[0064] In this embodiment, the liquid transfer pump 52 for supplying liquefied flammable gas 50a, the flammable gas piping 53 arranged so that a portion of it passes through a high-temperature region 53a, and the flammable gas burner 55 for blowing in the flammable gas 50b that has flowed through the flammable gas piping 53 correspond to the liquefied flammable gas utilization device.

[0065] (Variations) Various variations exist for the liquefied flammable gas utilization apparatus of this embodiment. Each variation will be described below. Note that these variations can be combined with each other.

[0066] <1> In Figure 3, the flammable gas piping 53 was arranged to pass through the first region 31 of the clinker cooler 30 and then connect to the flammable gas burner 55 through the outside of the clinker cooler 30. However, the region through which the flammable gas piping 53 passes within the clinker cooler 30 is arbitrary. For example, the flammable gas piping 53 may be provided to pass through the second region 32 in addition to the first region 31. As another example, the flammable gas piping 53 may be arranged to pass through the second region 32 of the clinker cooler 30 and then connect to the flammable gas burner 55 through the outside of the clinker cooler 30. As yet another example, the flammable gas piping 53 may be arranged to pass through the third region 33 of the clinker cooler 30 and then connect to the flammable gas burner 55 through the outside of the clinker cooler 30.

[0067] When the flammable gas 50b is of high purity, the probability of ignition is extremely low regardless of temperature. For example, in the case of ammonia, the flammability range is 15.5% to 27% by volume, and if the purity exceeds, for example, 80% by volume, spontaneous combustion will not occur. Even for hydrogen, one of the most easily spontaneously combustible gases, the maximum value of the flammability range is about 75% by volume. Therefore, it is unlikely that the flammable gas piping 53 will spontaneously ignite while liquefied flammable gas (50a, 50b) is flowing through it, whether in a liquid or gaseous state, regardless of the temperature range it passes through within the clinker cooler 30.

[0068] However, from a safety standpoint, when the flammable gas piping 53 is routed through the clinker cooler 30, it is more preferable that it is routed through a region where the temperature is below the ignition point of the flammable gas 50b. For example, if the liquefied flammable gas 50a is ammonia, the ignition point of ammonia is approximately 650°C, so it is preferable that the flammable gas piping 53 is routed through one or both of the first region 31 and the second region 32 of the clinker cooler 30.

[0069] (2) As shown in Figure 4, the flammable gas piping 53 may pass through each region (31, 32, 33) of the clinker cooler 30 and then connect to the flammable gas burner 55 through the outside of the clinker cooler 30.

[0070] Furthermore, as shown in Figure 5, the flammable gas piping 53 may be configured to pass through each region (31, 32, 33) of the clinker cooler 30 and may be equipped with multiple valves (61, 62, 63) to control the flow rate through each region. By adjusting each valve (61, 62, 63), the flow rate of liquefied flammable gas 50a toward each region (31, 32, 33) is controlled. This makes it possible to control the temperature of the flammable gas 50b at the time it is supplied to the injection point (flammable gas burner 55).

[0071] Furthermore, when controlling the flow rate of liquefied flammable gas 50a or flammable gas 50b passing through each region (31, 32, 33), three-way valves (64, 65) may be used as shown in Figure 6.

[0072] <3> As shown in Figure 7, the flammable gas 50b in gaseous state may be mixed with primary air 73 flowing through primary air piping 72 and then blown in from the injection point (flammable gas burner 55).

[0073] The liquefied flammable gas utilization apparatus shown in Figure 7 comprises a primary air blower 71, a primary air piping 72 through which primary air 73 flows, and a valve 74 installed in the primary air piping 72. The flammable gas piping 53 passes through a region (high temperature region 53a) within the clinker cooler 30 and is connected to the primary air piping 72 at a point before reaching the injection point. A portion of the primary air piping 72 is provided to pass through a region within the clinker cooler 30. In other words, the primary air piping 72 is provided to pass through a high temperature region 72a. The primary air piping 72 passes through a region (high temperature region 72a) within the clinker cooler 30 and is connected to the flammable gas piping 53 at a point before reaching the injection point.

[0074] According to the above configuration, the primary air 73 flowing through the primary air piping 72 is heated as it passes through the high-temperature region 72a, and then mixed with the combustible gas 50b flowing through the combustible gas piping 53. As a result, the combustible gas 50b is injected in a preheated state, improving combustion efficiency.

[0075] In the configuration shown in Figure 7, the flammable gas 50b is mixed with the primary air 73 while flowing through the flammable gas piping 53. Therefore, the concentration of the flammable gas 50b contained in the mixed gas may be within the combustion range, and in such cases, there is a concern that the flammable gas 50b may ignite while flowing through the flammable gas piping 53. In view of this, it is preferable that the piping routes of the flammable gas piping 53 and the primary air piping 72 be predetermined so that the gas temperature at the confluence point of the flammable gas piping 53 and the primary air piping 72 is below the ignition point of the flammable gas 50b.

[0076] Alternatively, valve 74 may be adjusted so that the concentration of flammable gas 50b in the mixed gas does not fall within the flammability range.

[0077] As shown in Figure 8, the flammable gas 50b and the heated primary air 73 may be supplied to a common injection point (flammable gas burner 55) without being mixed. More specifically, the flammable gas burner 55 may have multiple ports, and the primary air pipe 72 may be connected to a port other than the port to which the flammable gas pipe 53 is connected. In this case, unlike the configuration shown in Figure 7, the concern that the flammable gas 50b will ignite while flowing through the flammable gas pipe 53 is extremely low.

[0078] <4> In the configurations shown in Figures 7 and 8, the atmosphere is used as the primary air 73, and the primary air piping 72 through which this primary air 73 flows is provided to pass through the clinker cooler 30. In contrast, as shown in Figure 9, the atmospheric gas inside the clinker cooler 30 may be used as the primary air 73. In this case as well, the primary air piping 72 passes through the clinker cooler 30, which is a high-temperature region, before being led to the injection point (flammable gas burner 55).

[0079] The atmospheric gas inside the clinker cooler 30 mainly contains scattered dust derived from clinker 3. Since the combustible gas 50b contains almost no ash, its radiant heat transfer during combustion is lower compared to coal, which is the main fuel. In the configuration shown in Figure 9, primary air 73 containing scattered dust is blown in together with the combustible gas 50b from the injection point, so the scattered dust functions as a radiant heat transfer medium during the combustion of the combustible gas 50b, contributing to the stabilization of the combustion of the combustible gas 50b.

[0080] In the example shown in Figure 9, the case where the flammable gas piping 53 and the primary air piping 72 merge is shown, similar to Figure 7. However, as shown in Figure 8, the two pipes (53, 72) may not merge, and the flammable gas 50b and primary air 73 may be blown in from the same location. In this case, similar to Figure 8, a primary air blower 71 may be used, and it is preferable that this primary air blower 71 has heat resistance.

[0081] <5> When the atmospheric gas inside the clinker cooler 30 is used as primary air 73, a dust collector 75 for collecting scattered dust contained in the extracted atmospheric gas may be installed along the path of the primary air piping 72 (see Figure 10). The scattered dust collected by the dust collector 75 can be used, for example, by mixing it with the clinker 3 discharged from the clinker cooler 30, or by mixing it with cement in the finishing process of cement manufacturing where gypsum or the like is added.

[0082] <6> As shown in Figure 11, the flammable gas 50b flowing through the flammable gas piping 53 and the high-temperature primary air 73 flowing through the primary air piping 72 may be mixed by the ejector 76. The mixed gas is blown in through the flammable gas burner 55. The ejector 76 can be operated by the power generated by the flammable gas 50b that has vaporized and become high-pressure. In this case, a dust collector 75 may be provided to prevent thinning of the ejector 76 due to scattered dust contained in the extracted atmospheric gas.

[0083] <7> In the above embodiment, the flammable gas 50b is sent through the flammable gas piping 53 to the flammable gas burner 55 by the liquid supply pressure of the liquid supply pump 52 and the vaporization expansion pressure generated when the liquefied flammable gas 50a is vaporized. However, the present invention does not exclude a configuration in which a blower such as a Roots blower is installed in the flammable gas piping 53 to secure the pressure necessary to blow the vaporized flammable gas 50b from the flammable gas burner 55.

[0084] <8> In Figures 7 and 8, the primary air piping 72 is shown to pass through the region inside the clinker cooler 30 (high-temperature region 53a), but it may also pass through the extraction piping (41, 42, 43: see Figure 2) for extracting the atmospheric gas inside the clinker cooler 30. This point is also related to the content of the second embodiment and will be explained in the section on the second embodiment.

[0085] [Second Embodiment] A second embodiment of the liquefied flammable gas utilization apparatus, liquefied flammable gas utilization method, and cement manufacturing equipment according to the present invention will be described below. Note that parts common to the first embodiment described above will be simplified or omitted as appropriate.

[0086] Figure 12 is a schematic diagram illustrating the structure of the liquefied flammable gas utilization device of this embodiment, following Figure 2. This embodiment differs from the first embodiment in that the flammable gas piping 53 passes through the extraction piping (in this case, the exhaust gas extraction piping 41) for extracting atmospheric gas from inside the clinker cooler 30, rather than through the clinker cooler 30 itself.

[0087] As described above, the exhaust gas extraction pipe 41 is a pipe for extracting the atmospheric gas present in the first region 31 of the clinker cooler 30 and guiding it out of the system. In other words, the inside of the exhaust gas extraction pipe 41 contains air at a temperature similar to that of the atmosphere present in the first region 31 of the clinker cooler 30. Therefore, the internal space of the exhaust gas extraction pipe 41 corresponds to the high-temperature region 53a.

[0088] In other words, in this embodiment as well, similar to the first embodiment, the delivered liquefied flammable gas 50a vaporizes as it passes through the high-temperature region 53a while flowing through the flammable gas piping 53, becoming flammable gas 50b. This flammable gas 50b flows through the flammable gas piping 53 and is supplied to the flammable gas burner 55.

[0089] In the example shown in Figure 12, the flammable gas piping 53 is routed through the exhaust gas extraction piping 41, but it may also be routed through other extraction piping (raw material drying extraction piping 42, calcination furnace extraction piping 43). Figure 13 shows an example configuration in which the flammable gas piping 53 is routed through the raw material drying extraction piping 42, following the example in Figure 12.

[0090] As described above with reference to Figure 2, the extracted gas from the clinker cooler 30 through the extraction piping 43 for the calcination furnace is sent to the calcination furnace 13 and used as part of the combustion air. In addition, the extracted gas from the clinker cooler 30 through the extraction piping 42 for raw material drying is sent to the raw material process and used as part of the drying air for the raw material M1. If the flammable gas piping 53 is routed through these extraction pipes (42, 43), the temperature of the extracted gas flowing through each extraction pipe (42, 43) may decrease slightly due to heat exchange between the pipe wall of the flammable gas piping 53 through which the liquefied flammable gas 50a flows and the atmosphere inside the clinker cooler 30. On the other hand, the extracted gas flowing through the exhaust gas extraction piping 41 is not used for combustion or drying and is discharged outside the system. Therefore, when the flammable gas piping 53 passes through the extraction piping that extracts the atmospheric gas from within the clinker cooler 30, it is particularly preferable for it to pass through the extraction piping 43 for the calcination furnace.

[0091] In the configuration of this embodiment, it is possible to combine it with the configurations described above in the first embodiment as appropriate.

[0092] In the first embodiment described above with reference to Figures 7 and 8, it was explained that the atmospheric air, which is the primary air 73 taken into the primary air piping 72 from the primary air blower 71, is heated as it passes through the region (high-temperature region 53a) inside the clinker cooler 30. However, similar to the flammable gas piping 53 in this embodiment, the primary air piping 72 may also be heated by passing through the extraction piping (41, 42, 43).

[0093] [Third Embodiment] A third embodiment of the liquefied flammable gas utilization apparatus, liquefied flammable gas utilization method, and cement manufacturing equipment according to the present invention will be described below. Note that parts common to those already described in the above embodiments will be simplified or omitted as appropriate.

[0094] Figure 14 is a schematic diagram illustrating the structure of the liquefied flammable gas utilization device of this embodiment, following Figure 3. This embodiment differs from the first and second embodiments in that the flammable gas piping 53 is connected to the main burner 21 instead of the flammable gas burner 55. In other words, in this embodiment, the liquefied flammable gas utilization device does not have a flammable gas burner 55.

[0095] The main burner 21 has multiple ports (for example, a double-pipe burner). Of the multiple ports provided by the main burner 21, a piping 53 for flammable gas is connected to a port other than the port into which the primary air 25 flows. With this configuration, flammable gas 50b is supplied from the main burner 21 along with the main fuel (not shown) and primary air 25.

[0096] Other elements can be appropriately combined with the configurations described above in the first or second embodiment.

[0097] [Fourth Embodiment] A fourth embodiment of the liquefied flammable gas utilization apparatus, liquefied flammable gas utilization method, and cement manufacturing equipment according to the present invention will be described below. Note that parts common to those already described in the above embodiments will be simplified or omitted as appropriate.

[0098] Figure 15 is a schematic diagram illustrating the structure of the liquefied flammable gas utilization device of this embodiment, following Figure 3. This embodiment differs from the first to third embodiments in that the flammable gas piping 53 is connected to the calcination furnace 13, rather than to the front part 20b of the cement kiln 20. That is, according to the configuration in Figure 15, the flammable gas 50b vaporized while flowing through the flammable gas piping 53 is blown into the calcination furnace 13 through the flammable gas burner 55.

[0099] Figure 16 is a schematic diagram illustrating another structure of the liquefied flammable gas utilization device of this embodiment, following Figure 3. This embodiment differs from the first to third embodiments in that the flammable gas piping 53 is connected to the tail end 20a of the cement kiln 20, rather than the front end 20b. That is, according to the configuration in Figure 16, the flammable gas 50b vaporized while flowing through the flammable gas piping 53 is blown into the cement kiln 20 from the tail end 20a side through the flammable gas burner 55.

[0100] In the configurations shown in Figures 15 and 16, the combustible gas 50b can be used as a fuel for calcination or firing, thus reducing the amount of fuel, which mainly consists of coal, and is expected to reduce CO2 emissions during cement production.

[0101] Other elements can be appropriately combined with the configurations described in the first to third embodiments. [Explanation of Symbols]

[0102] 1: Cement manufacturing equipment 3: Klinka 11: Preheater 13: Temporary ignition furnace 14: Temporary ignition furnace burner 20: Cement Kiln 20a: Kiln bottom 20b: Kiln front 21: Main Burner 25: Primary air 30: Clinka Cooler 31:First area 32:Second area 33:Third area 41: Exhaust gas extraction piping 42: Bleeding piping for drying raw materials 43: Extraction piping for calcination furnace 50a: Liquefied flammable gas 50b: Gas obtained by vaporizing liquefied flammable gas (flammable gas) 51: Tank 52: Liquid transfer pump 53: Piping for flammable gases 53a: High temperature area 55: Burner for flammable gases 71: Primary air blower 72: Primary air piping 72a: High temperature area 73: Primary air 74: Valve 75: Dust collector 76: Ejector CA: Atmosphere M1: Cement raw material

Claims

1. A device for utilizing liquefied flammable gas, configured to be attachable to a cement manufacturing facility having a calcination furnace for calcining cement raw materials, a cement kiln for firing the cement raw materials calcined in the calcination furnace to produce clinker, and a clinker cooler connected to the front of the cement kiln, The system includes a tank storing liquefied flammable gas and one or more injection points located in the group consisting of the front of the cement kiln, the rear of the cement kiln, and the calcination furnace, connected via either or both of the clinker cooler and the extraction piping through which the extracted gas extracted from the clinker cooler flows. The aforementioned liquefied flammable gas contains 70% by volume or more of ammonia. A liquefied flammable gas utilization apparatus characterized in that the flammable gas piping vaporizes the liquefied flammable gas while it is flowing, and then supplies the flammable gas obtained from the vaporization of the liquefied flammable gas to the injection point.

2. The liquefied flammable gas utilization apparatus according to claim 1, characterized in that the piping for the flammable gas is not equipped with a blower to promote the flow of the flammable gas.

3. The liquefied flammable gas utilization apparatus according to claim 1 or 2, characterized in that the flammable gas piping passes through a region within the clinker cooler or the extraction piping where the ambient temperature is in the range of 150°C to 1000°C.

4. The liquefied flammable gas utilization apparatus according to claim 3, characterized in that the piping for the flammable gas is configured to pass through multiple regions with different ambient temperatures within the clinker cooler or the extraction piping, and is provided with multiple valves for controlling the flow rate through each region.

5. A burner is attached to the end of the flammable gas piping on the injection point side, and the flammable gas is injected into the injection point. The system includes a primary air pipe through which primary air flows and which connects to the flammable gas pipe at a location upstream of the burner, via one or both of the clinker cooler and the extraction piping, The liquefied flammable gas utilization apparatus according to any one of claims 1 to 4, characterized in that the flammable gas piping is configured to guide a mixed gas, which is a mixture of the flammable gas and the primary air, to the burner at a location downstream of the connection point with the primary air piping.

6. A burner having multiple ports and attached to the end of the flammable gas piping on the injection point side, which injects the flammable gas into the injection point through one or more of the ports, A liquefied flammable gas utilization apparatus according to any one of claims 1 to 4, characterized in that primary air flows into the apparatus and is connected to a primary air pipe that is different from the port to which the flammable gas pipe is connected among a plurality of ports provided on the burner, via one or both of the clinker cooler and the extraction pipe.

7. The liquefied flammable gas utilization apparatus according to claim 5 or 6, characterized in that the primary air piping is configured such that one or both of the atmospheric gas in the clinker cooler and the extracted gas in the extraction piping flow toward the burner.

8. The liquefied flammable gas utilization apparatus according to claim 7, characterized in that the primary air piping comprises a primary air blower that promotes the flow of one or both of the atmospheric gas in the clinker cooler and the extracted gas in the extraction piping within the primary air piping, and a dust collector that collects scattered dust contained in the gas flowing through the primary air piping.

9. A method for utilizing liquefied flammable gas in a cement manufacturing process that involves firing cement raw materials to produce a cement kiln, A step of supplying liquefied flammable gas to a flammable gas pipe arranged so as to pass through either or both the clinker cooler and the extraction pipe through which the extracted gas extracted from the clinker cooler flows, The process includes the steps of vaporizing the liquefied flammable gas in a liquid state while it is flowing through the flammable gas piping, and then blowing the resulting flammable gas into one or more blowing locations set in the group consisting of the front of the clinker cooler, the rear of the clinker cooler, and the calcination furnace, A method for utilizing liquefied flammable gas, characterized in that the liquefied flammable gas contains 70% by volume or more of ammonia.

10. A calcination furnace for calcining cement raw materials, A cement kiln that fires the cement raw materials that have been calcined in the calcination furnace to produce clinker, A clinker cooler connected to the front of the cement kiln, The system comprises a tank for storing liquefied flammable gas and flammable gas piping that connects one or more injection points, which are set in the group consisting of the front of the clinker cooler, the rear of the clinker cooler, and the calcination furnace, via the inside of the clinker cooler or through extraction piping through which extracted gas extracted from the clinker cooler flows. The aforementioned liquefied flammable gas contains 70% by volume or more of ammonia. The piping for the flammable gas is characterized in that it vaporizes the liquefied flammable gas in a liquid state while it is flowing, and then supplies the flammable gas obtained from the vaporization of the liquefied flammable gas to the injection point.

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