JPS5928727B2 - High-pressure steam production equipment used for power generation using hot water - Google Patents

Description

Detailed Description of the Invention The present invention utilizes exhaust heat from factories, etc. to generate high-pressure steam of a hydrocarbon compound as a working medium, drives a turbine with the high-pressure steam, and converts the exhaust heat into electrical energy. This invention relates to a high-pressure steam production device used for power generation using hot water for recovery.

Conventionally, in power generation systems using organic working media, halogenated hydrocarbon compounds, such as fluorocarbon refrigerants (R-11
tR-12PR-13) etc. are widely used.

An indirect heat exchange method is employed in which these compounds are heated and evaporated by a heat source flowing through a group of heat transfer tubes in an evaporator.

On the other hand, apart from the above, about half of the energy used in factories related to the mining and manufacturing industries etc. is released into the atmosphere as waste heat.
Given the current situation where waste heat is being wasted into rivers, oceans, etc., there is an increasing demand for the development of new technology that can recover and effectively utilize waste heat.

Therefore, it is conceivable to utilize such waste heat for evaporating the organic working medium.

However, when using waste heat from the mining and industrial industries as a heat source, such as heated waste water at a low temperature level of 100°C or lower or exhaust gas at a temperature of 200°C or lower, the thermal efficiency due to the liking cycle of an organic working medium is 20% to 10%. %, a technology for exchanging a large amount of heat to the working medium is required, and the equipment becomes large and bulky.

In addition, the organic working medium used for power generation at the above-mentioned low temperature level is generally chemically stable and has a low boiling point,
Moreover, it is poorly soluble in water and hot water.

Therefore, a method of directly dispersing and evaporating these working media in hot water, ie, a direct contact method, can be considered.

However, halogenated hydrocarbon compounds such as Freon R-11 and R-12 are generally chemically stable compounds in a temperature range of 100°C or less, but in moisture they are only a few grams per year. Hydrolyzes to produce hydrochloric acid and hydrofluoric acid.

Furthermore, it is known that when iron, copper, etc. coexist, the hydrolysis reaction is promoted by the catalytic action of these metals, causing corrosion of the equipment material.

Further, in such a direct contact method, in order to effectively utilize the energy of the hot water, it is advantageous to bring the falling hot water and the working medium into contact with each other in a countercurrent manner.

However, when the above-mentioned halogenated hydrocarbon compound is used as a working medium, the density of the working medium is higher than that of hot water;
Because it settles in hot water, it becomes a device with a complex structure.

Therefore, conventional halogenated hydrocarbon compounds cannot be advantageously used in direct contact mode with hot water.

Therefore, the object of the present invention is to use hot water obtained by utilizing waste heat from the above-mentioned mining and manufacturing industries, etc., or hot water obtained as direct heated waste water, and to use a specific hydrocarbon compound as a working medium. A high-pressure steam production device used for power generation using hot water that brings hot water into direct contact with a working medium to generate high-pressure steam as the working medium, drives a turbine with the steam, and effectively recovers waste heat as electrical energy. This is what we provide.

Another object of the present invention is to provide a power generation method using hot water that has high exhaust heat utilization efficiency and does not cause corrosion of equipment materials.

Ru. Still another object of the present invention is to provide a high-pressure steam production apparatus that can be effectively used in the above method, has a simple structure, and is easy to design.

A power generation method using hot water that achieves the above object of the present invention is a method of generating electricity by driving a turbine with high-pressure steam as a working medium. is dispersed in the form of droplets into the hot water falling from the evaporator, and is brought into direct contact with the falling hot water in a countercurrent manner to preheat it, and then brought into direct contact with the hot water in the evaporator to evaporate the working medium. It is characterized by producing high-pressure steam, which is further heated before being supplied to the turbine.

In addition, the high-pressure steam production apparatus of the present invention has a condenser at the bottom of the evaporator that generates high-pressure steam of the working medium by directly contacting the working medium and hot water. A high-pressure steam generation device with a structure that combines a preheater with nozzles that distribute the heat to the atmosphere, and a heater that heats the high-pressure steam of the generated working medium are combined, and a condenser is attached to make the use of high-pressure steam more efficient. The present invention is characterized in that the working medium and the hot water are brought into countercurrent contact in the most rational manner.

As described above, the high-pressure steam generator of the present invention includes an evaporator in the upper part of the apparatus and a preheater in the lower part.

The working medium flows from the lower part of the preheater, is sufficiently dispersed in the form of droplets from the evaporator into the hot water that descends inside the preheater, and rises within the preheater due to its buoyancy, collapsing with the falling hot water. It is preheated by direct contact with the flow type.

The working medium heated in this manner enters the upper evaporator and is boiled by the high-temperature hot water flowing therein, turning into high-pressure steam while stirring the liquid vigorously.

The high-pressure steam generated here is nearly saturated and also contains water vapor from hot water, so it is necessary to prevent this steam from liquefying in the equipment piping route and turbine, and to prevent the turbine from liquefying. Also to increase thermal efficiency,
A separate steam heater is installed on the high-pressure steam piping route from the evaporator to the turbine, and the high-pressure steam is heated before being supplied to the turbine.

In addition, the hot water that flows down the preheater of the high-pressure steam generator and is discharged from the bottom is circulated to the heat exchanger of the waste heat source in the mining and industrial industries, where it is reheated and flows into the evaporator for circulation. However, if hot water is used as hot water from a factory, etc., and the heated wastewater is heat-exchanged with a high-pressure steam generator and then discharged to the outside, the discharged heated wastewater contains approximately several hundred ppm. Since the working medium may be dissolved in concentration, it is advantageous to provide a recovery device, for example consisting of a deaerator, a compressor, a condenser, etc., for recovering this working medium.

Due to the above-mentioned actions and functions, the working medium used in the implementation of the present invention has a low boiling point, so that it can be evaporated by the hot water used.
Preferably, a material having a low boiling point of 40° C. or lower, a density lower than that of hot water, and hardly soluble in hot water is used.

However, effective working media that drive a turbine as high-pressure steam and have the above-mentioned performance exist among hydrocarbon compounds.

That is, in the present invention, among these, those that can compress (and cool) and liquefy petroleum-based or natural gas-based hydrocarbon compounds that are gaseous at room temperature and normal pressure are particularly preferred.
In some cases, materials that are originally liquid at room temperature but can liquefy (condense) vapor may also be used.

In use, from the viewpoint of liquefaction, evaporation, handling, etc., hydrocarbon compounds having 3 and 4 carbon atoms are particularly preferred as working media, specifically propane (boiling point -42.2°C, density (as a liquid) 0). .58241/crit), n-butane (boiling point -0.5°C, density (as liquid) 0.5788
1/i), isobutane (boiling point -11.7°C, density (as liquid) 0.5 s 2 f/i),
If appropriate, n-butane-isobutane mixtures, propane-propylene mixtures and butane-butylene mixtures are also used.

Further, in carrying out the present invention, two or more types of working media may be used in combination.

Next, the apparatus of the present invention will be specifically explained based on the illustrations of the drawings.

FIG. 1 is for explaining a power generation method using hot water, which is composed of a high-pressure steam generator combining an evaporator and a preheater, a steam heater, a turbine-generator, a condenser, and a hot water exchanger. Figure 2 shows a schematic diagram of a high-pressure steam generator that combines an evaporator and a preheater, and Figure 3 shows another method of power generation for hot water using hot water and waste heat. A system diagram for explanation is shown, and a schematic diagram of the large-scale high-pressure steam generator is shown in FIGS. 4 and 5, respectively.

In Figure 1, the hot water is passed through the hot water heat exchanger 1 through the exhaust heat source route 2,
The working medium is heated by the exhaust heat source passing through 3, and a part of the working medium flows into the evaporator 8 of the high-pressure steam generator 7 from paths 5 and 6 through the hot water pump 4, passes through the weir 9, and is heated in the preheater 10. The working medium is evaporated by the thermal energy of the hot water.

In addition, other hot water from the hot water pump 4 enters the steam heater 12 via a path 11, where it heats steam, and then passes through the path 1.
3, the hot water is sprayed in a radial direction approximately at the center of the evaporator 8 by the hot water sprinkler 14, and the jet stream further accelerates the evaporation of the working medium.

The temperature of the hot water in the evaporator 8 is lowered by the evaporation of the working medium, and it further descends and is dispersed into droplets in the preheater 10, where it comes into direct contact with the working medium rising due to its buoyancy in a countercurrent manner, thereby exchanging heat. After further lowering the temperature, it flows out from the bottom of the preheater 10,
It is reheated in the hot water heat exchanger 1 via the path 15, and then transferred to the evaporator 8.
circulated within.

On the other hand, the liquefied working medium is dispersed in the form of droplets from the porous nozzle 16 at the bottom of the preheater 10 into the hot water descending inside the preheater 10 as described above, and comes into direct contact with the hot water in a countercurrent manner. It exchanges heat and is heated and rises to the evaporator 8 where it is evaporated.

The high-pressure steam of the working medium evaporated in the evaporator 8 passes through the mist shield 17 and the mesh eliminator 18, and enters the steam heater 12 via the path 19, where it is heated and becomes supersaturated high-temperature, high-pressure steam.

This steam flows into the turbine 21 from the path 20, drives the turbine 21, and causes the generator 22 to generate electric power.

Turbine 21. The working medium vapor after driving is condensed and liquefied in condensers 23 and 24.

The condenser 24 uses cold water, seawater, cold water, and cooling water, and this cooling water is caused to flow through paths 26 and 27 by a cooling water pump 25.

The working medium condensed and liquefied here accumulates in the lower part of the condenser 24.

The high-pressure steam contains water vapor from hot water, and this water vapor also liquefies into water in the condensers 23 and 24, so the working medium and water are separated at the bottom of the condenser 24 by their density difference. and the water is discharged from the lower passage 28 of the condenser 24.

On the other hand, the liquefied working medium is extracted from the path 29, enters the condenser 23 via the path 31 by the working medium pump 30, is heated by exchanging heat with high-pressure steam, and is then preheated again through the path 32. It is circulated and used to the porous nozzle 16 at the bottom of the vessel 10.

FIG. 2 more specifically shows the flow of the working medium and hot water in the high-pressure steam generator using arrows, and the figure numbers are the same as those in FIG. 1.

That is, as described above, in the present invention, the preheater 10
Since the upper edge protrudes to the bottom of the evaporator 8 as a weir 9, the hot water descends as an average laminar flow along the inner peripheral surface of the preheater 10, and the working medium from the porous nozzle 16 flows into a large number of liquids. The droplets form an aggregate and rise inside the laminar flow of the hot water to perform heat exchange, but this upward flow is then transferred from the hot water sprinkler 14 installed at the center below the weir 9 to the laminar flow. The hot water injected in the radial direction comes into contact again with the annular hot water flow flowing down over the weir 9, and sufficient heat exchange takes place.

The results of concrete implementation using the apparatus shown in FIGS. 1 and 2 are as follows.

That is, hot water is heated to about 100°C in the hot water heat exchanger 1 using an exhaust heat source such as exhaust gas from a factory, and then the high pressure steam generator 7
When n-butane is circulated through the evaporator 8 at a flow rate of about 10 tons per hour, and n-butane is used as a working medium, it is directly mixed with the hot water through the preheater 10 and evaporated in the evaporator 8. becomes high pressure steam of about 8 to 8.3 kg/i.

In this case, the amount of n-butane evaporated is approximately 2.9 tons per hour, the average temperature on the evaporator source side is approximately 70°C, and the average temperature on the steam side is approximately 69°C.
Indicates °C.

This high-pressure steam has a composition containing about 4% water vapor, and is further heated to about 90° C. in a steam heater 12, and the obtained high-temperature and high-pressure steam drives a turbine 21.

In this operation, the turbine-generator generates approximately 40 to 40
You can get 5KW of power.

Furthermore, the steam flowing out from the turbine 21 is passed through a condenser 23,
24, and the temperature of the liquefied n-butane here varies somewhat depending on the inlet temperature of the cooling water, but exhibits a temperature of about 32°C to about 35°C.

This liquefied n-butane is separated from water at the bottom of the condenser 24,
The working medium pump 30 is used to cool the condenser 23 and is approximately 4
After being raised to a temperature of 5°C, it is sent to the lower part of the preheater 10.

Through the porous nozzle 16 of the preheater 10, the liquefied n-butane is dispersed in the falling hot water as droplets of about 4 mm in size from about 2 mm, and flows through the preheater 10 while exchanging heat with the hot water in a countercurrent manner. The temperature rises to about 70° C., and evaporates in the evaporator 8 as described above to become high-pressure steam.

At this time, the temperature of the hot water discharged from the lower part of the preheater 10 is
The temperature reaches approximately 65°C, and the temperature reaches approximately 1
heated to 00°C.

The above example is an example of using hot water obtained using waste heat, but in the present invention, hot water at 100°C from a factory etc. is also used.
Heated waste water having a temperature range from 1 to 60° C. can be used instead of the hot water described above.

However, when hot water is used, the hot water flowing out from the lower part of the preheater is normally not circulated to the hot water heat exchanger like the hot water (but is discharged outside the system).

This discharged liquid contains hundreds of n-butane, which is a working medium.
Dissolved and also contains fine droplets of n-bupmtan.

Such working medium is recovered from the effluent.

Further, the flow rate, temperature, etc. of heated waste water from factories and the like may not always be constant, and the amount of heated waste water may be insufficient during use.

In such cases, in order to maintain the flow rate and temperature of heated wastewater under certain conditions, it is necessary to circulate some of the heated wastewater and heat it using other waste heat sources from factories, such as exhaust gas. required to use it.

Next, an example in which heated waste water is used as hot water will be explained based on FIG.

In FIG. 3, a part of the heated waste water discharged from the lower part of the preheater 10 passes through a path 15 and is heated by another waste heat source in a regenerative heat exchanger 1', where it is routed from a factory etc. It is sent to the steam generator 7 by the pump 4 together with the heated wastewater sent at 34, and moves in the same manner as explained in FIG. 1.

On the other hand, the remaining heated wastewater flows through a path 35 to a degassing tower 37 whose pressure is reduced by a compressor 36, where it is dissolved or mixed to a temperature of ℃
・Release of working medium (n-butane).

The heated wastewater that has released n-butane is discharged from the system through a path 38 at the bottom of the degassing tower 37.

Here, the pressure inside the degassing tower 37 is set to about 500 mmH? If the temperature is maintained below, the concentration of n-butane dissolved in hot waste water will decrease from about 350 ppm to about 10 ppm.

The n-butane vapor released in the degassing tower 37 is routed through the path 39.
From there, it is sent to a compressor 36 where it is pressurized, and then liquefied in a condenser 40.

The liquefied n-butane accumulates in the lower part of the condenser 40, and the water contained therein is separated and discharged from the system through a path 41, but the remaining liquefied n-butane flows through a path 42 into the condenser 24.
The working medium enters the working medium sump at the bottom of the condenser 23, 24 by the pump 30 together with the n-butane liquefied in the condensers 23, 24.
This n-
Butane is heated and evaporated, driven by a turbine, and condensed and liquefied repeatedly.

Note that the cooling water of the condenser 40 flows from the cooling water pump 25 through the path 26 and the paths 43 and 44.

Other figure numbers and other mechanisms in Figure 3 are shown in Figure 1 (
and FIG. 2), detailed explanation here will be omitted.

Next, in the apparatus shown in FIGS. 4 and 5, the evaporator 8 is made of a horizontal cylindrical can, and three preheaters 10 are attached to the bottom of the evaporator 8. This type is suitable for large-scale equipment. Are suitable.

A porous nozzle 16 is provided at the bottom of each of these preheaters 10.

Further, the hot water sprinkler 14 in the evaporator 8 is also provided so as to be branched into three branches so as to be located above each of the preheaters 10.

That is, in the evaporator 8, the hot water flowing from the weir 9 and the hot water sprinkler 14 and the working medium that has risen while being heated in each preheater 10 are sufficiently mixed to efficiently evaporate and transfer. Designed to carry out heat.

Further, this structure has the advantage that the number of preheaters can be reduced or increased to two or four or more depending on the scale of the device or the required power generation output.

It goes without saying that a device having this structure can be used in place of the high-pressure steam generator shown in FIG. 1 or 3.

Note that the other figure numbers in FIG. 4 are the same as those in FIG. 1 or FIG. 3, so detailed explanation will be omitted.

According to the present invention, waste heat sources can be effectively utilized and recovered as electrical energy, which is advantageous for energy saving.

With the above configuration, the working medium can be heated effectively, and the working medium can be sufficiently preheated with the hot water falling from the evaporator, so the heat exchange rate is excellent, and the waste heat utilization efficiency is therefore high. Also, unlike conventional working media, corrosion of equipment materials does not occur.

In addition, compared to the conventional case where halogenated hydrocarbon compounds are indirectly heated and evaporated, the volume-based heat transfer coefficient value is approximately 2.
, 5 times to about 4 times. Therefore, in the present invention, when the volume of the heat transfer section of the evaporator obtains the same electric power, the volume is reduced to about 1/2.5.
It is possible to reduce the size to about 1/4, and also eliminates the need for a large number of expensive heat exchanger tube groups such as those of the conventional indirect type, making it possible to significantly reduce device cost and energy consumption.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of the device of the present invention, FIG. 2 is a schematic diagram of the high-pressure steam generator of the present invention, FIG. 3 is a system diagram of another device for explaining the present invention, and FIG. 4 is a system diagram of the present invention. FIG. 5 is a schematic diagram of another high-pressure steam generator used in the invention, and FIG. 5 is a sectional view taken along the line V-V in FIG. 4. 1... Hot water heat exchanger, 1'... Regenerative heat exchanger, 4
...Hot water pump, 7...High pressure steam generator, 8...
・Evaporator, 10... Preheater, 12... Steam heater,
14... Hot water sprinkler, 16... Porous nozzle, 21.
... Turbine, 22... Generator, 23.24... Condenser, 25... Cooling water pump, 30... Working medium pump, 36... Compressor, 37... Deaeration tower , 40...
·Condenser.

Claims (1)

[Claims] 1. An evaporator with a heated hot water inlet at the lower edge, a high-pressure steam outlet for the working medium at the upper edge, and a hot water sprinkler that sprays radial water at the center of the interior, with the circumferential surface projecting outward. and,
A vertical tube that has a hot water outlet at its lower end, a porous nozzle located at the lower part of the interior to disperse the working medium in droplets, and whose upper edge serves as an overflow weir that projects into the evaporator and continues below the evaporator. a high-pressure steam generator formed of a preheater, a heater that heats the high-pressure steam of the generated working medium by using a part of the hot water flowing into the evaporator, and A high-pressure steam production device used for power generation using hot water, comprising a condenser that condenses and liquefies medium vapor and condenses it into the porous nozzle of the preheater.