JP2010203376A - Evaporator in power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaporator made of a material having sufficient corrosion resistance against both ammonia and sulfuric acid. <P>SOLUTION: A power generation system includes a power generator 4, a turbine 3, an evaporator 1 generating heating medium vapor which is vapor of ammonia water to be supplied to the turbine as a heating medium, and a condenser 5 which condenses vapor exhausted from the turbine. In the evaporator, at least a heat conducting tube 1b is made of a material including a 51.0 to 62.5 mass% of nickel, a 14.5 to 16.5 mass% of chromium, a 15.0 to 17.0 mass% of molybdenum, a 4.0 to 7.0 mass% of iron, a 3.0 to 4.5 mass% of tungsten, and a 1.5 to 2.5 mass% of cobalt. The use of the material makes it possible to use sulfuric acid obtained in a sulfuric acid manufacturing plant, as a heat source in the evaporator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an evaporator in a power generation system.

  For example, in a sulfuric acid production plant, sulfuric acid at about 90 ° C. exiting an absorption tower is cooled with cooling water and sent to a product tank, and it is conceivable to use the heat of sulfuric acid at a low temperature.

  Conventionally, there is a low temperature power generation system using a Rankine cycle using ammonia as a heat medium, and hot water is generally used as the heat source, and therefore, at least a heat transfer portion of an evaporator, that is, a heat transfer tube. As the material, a material considering only the corrosion resistance against ammonia, for example, carbon steel has been used.

  By the way, as described above, when using the heat of sulfuric acid obtained in the sulfuric acid production plant as the heat source of such a power generation system, sulfuric acid is caused to flow through the heat transfer tube of the evaporator. As a material for the heat transfer tube, in particular, a material effective for ammonia and sulfuric acid, such as stainless steel, is used.

However, even when stainless steel is used as the material for the heat transfer tube in the evaporator, its corrosion resistance is not sufficient with respect to ammonia and sulfuric acid.
Then, this invention aims at providing the evaporator in the electric power generation system comprised with the material in which the heat-transfer member of an evaporator can exhibit sufficient corrosion resistance also to both ammonia and a sulfuric acid at least. .

In order to solve the above problems, an evaporator in a power generation system according to the present invention includes a generator and a turbine that rotates the generator, and heat medium vapor that is ammonia water or ammonia vapor supplied as a heat medium to the turbine. An evaporator in a power generation system having an evaporator for generating gas and a condenser for condensing exhaust steam from the turbine,
As materials for at least the heat transfer member in the evaporator, nickel (Ni) is 51.0 to 61.5 mass%, molybdenum (Mo) is 15.0 to 17.0 mass%, and chromium (Cr) is 14.5 to 16.5% by mass, iron (Fe) 4.0-7.0% by mass, tungsten (W) 3.0-4.5% by mass and cobalt (Co) 1.5-2.5% by mass By using what is included in each of these ranges, sulfuric acid obtained from the sulfuric acid production process is used as a heat source in the evaporator.

  Since the materials mentioned above are used for at least the heat transfer member of the evaporator, corrosion resistance is exhibited against both ammonia and sulfuric acid, and the heat of sulfuric acid obtained in the sulfuric acid production process can be recovered without hindrance. can do.

It is a mimetic diagram showing a schematic structure of a power generation system concerning an embodiment of the invention. It is a schematic diagram which shows schematic structure of the electric power generation system which concerns on other embodiment of this invention.

Hereinafter, an evaporator in a power generation system according to an embodiment of the present invention will be described with reference to FIG.
First, a schematic configuration of the power generation system will be described.

  This power generation system recovers waste heat by generating power using the heat of sulfuric acid at a low temperature, for example, about 90 ° C. obtained in a sulfuric acid production process, that is, a sulfuric acid production plant, and is used as a heat medium (called a working fluid). It can be operated with a carina cycle using aqueous ammonia (which is an aqueous ammonia solution).

  As shown in FIG. 1, the power generation system using this carina cycle includes an evaporator 1 that introduces ammonia water (hereinafter also referred to as a heat transfer medium), heats and evaporates, and ammonia evaporated in the evaporator 1. A gas-liquid separator 2 that guides vapor (including water vapor, hereinafter also referred to as heat medium vapor) and separates (entrained) liquid components contained in the heat medium vapor; The turbine 3 driven by the heat medium steam, the generator 4 rotated by the turbine 3, and the turbine exhaust discharged from the turbine 3 (hereinafter referred to as exhaust steam) The first heat medium for guiding the heat medium liquid condensed in the condenser 5 and having the liquid feed pump 15 in the middle of the condenser 5 that cools and condenses the exhaust steam. Liquid transfer pipe 11 and the above evaporation The first heat medium steam transfer pipe 12 for guiding the heat medium steam obtained in 1 to the steam turbine 3 via the gas-liquid separator 2 and the exhaust steam discharged from the steam turbine 3 are transferred to the condenser 5. The exhaust steam transfer pipe 13, the second heat medium liquid transfer pipe 14 for transferring the liquid component separated by the gas-liquid separator 2, that is, the high-temperature heat medium liquid, to the condenser 5, and the first heat The heat which is provided in the medium liquid transfer pipe 11 and the second heat medium liquid transfer pipe 14 and has the high temperature heat medium liquid from the gas-liquid separator 2 is applied to the low temperature heat medium liquid from the condenser 5. It is comprised from the heat exchanger 6 for heat recovery.

  The evaporator 1 is composed of an evaporator main body 1a filled with a heat transfer medium, and a heat transfer tube 1b provided in the evaporator main body 1a and guided with sulfuric acid as a heat source (also a heating fluid). The condenser 5 also includes an evaporator main body 5a through which exhaust steam is guided and a heat transfer pipe 5b that is provided in the evaporator main body 5a and through which a cooling fluid such as cooling water is guided to cool the exhaust steam. Has been.

  In the above power generation system, the low-temperature sulfuric acid of about 90 ° C. obtained in the sulfuric acid production plant is led to the heat transfer tube 1b of the evaporator 1, and the heat medium liquid in the evaporator main body 1a is heated and evaporated to produce heat medium vapor. Some ammonia water vapor is obtained.

  This heat-medium vapor | steam is guide | induced to the gas-liquid separator 2, and the liquid component accompanying this is isolate | separated. The heat-medium vapor | steam from which the liquid component was isolate | separated is guide | induced to the turbine 3, and the turbine 3 is driven. Then, the turbine 4 rotates the generator 4 to generate power.

  The exhaust steam exiting the turbine 3 enters the condenser body 5a of the condenser 5 and is cooled and condensed by the cooling water flowing in the heat transfer pipe 5b to become a heat medium liquid, which is the second heat medium liquid. It is transferred to the evaporator 1 through the transfer pipe 14 and again heated and evaporated with sulfuric acid.

  By the way, since sulfuric acid is led into the heat transfer tube 1b of the evaporator 1 and ammonia water as a heat transfer liquid is led into the evaporator main body 1a, at least the material of the heat transfer tube 1b is shown below. Such a material having corrosion resistance to ammonia and sulfuric acid is used.

  That is, nickel (Ni) is 51.0 to 61.5 mass%, molybdenum (Mo) is 15.0 to 17.0 mass%, chromium (Cr) is 14.5 to 16.5 mass%, iron (Fe ) Is 4.0 to 7.0% by mass, tungsten (W) is 3.0 to 4.5% by mass, and cobalt (Co) is included in each range of 1.5 to 2.5% by mass. Used. More precisely, to the above-mentioned components, the total of manganese (Mn) and vanadium (V) is added within the range of 0.5 to 1.3% by mass, and carbon (C), phosphorus (P) , Sulfur (S) and silicon (Si) are used in a total amount of 0.2% by mass or less.

By using such a material, corrosion resistance is exhibited against both ammonia and sulfuric acid, and it can sufficiently withstand use.
By the way, in the said embodiment, although what operate | moved by a carina cycle was demonstrated as an electric power generation system, For example, it can apply also to the evaporator of the electric power generation system which operate | moves by Rankine cycle.

Here, the Rankine cycle will be briefly described with reference to FIG.
This power generation system uses an ammonia liquid having a concentration of 100% as a heat medium. An evaporator 21 that guides the ammonia liquid, that is, the heat medium liquid, heats and evaporates, and ammonia vapor that is evaporated in the evaporator 21, that is, A turbine 22 driven by the heat medium steam and guided by the heat medium steam, a generator 23 rotated by the turbine 22, and exhaust steam which is turbine exhaust discharged from the turbine 22 is guided and cooled by cooling water. And a condenser 24 for condensation. Of course, the heat medium vapor evaporated in the evaporator 21 is transferred to the turbine 22 through the heat medium steam transfer pipe 31, and the exhaust steam discharged from the turbine 22 is transferred to the condenser 24 through the exhaust steam transfer pipe 32. The heat medium liquid condensed in the condenser 24 is transferred to the evaporator 21 through the heat medium liquid transfer pipe 33.

The description of the cooling system 25 of the condenser 24 is omitted.
The heat transfer tube 21b provided in the evaporator main body 21a of the evaporator 21 is led to sulfuric acid having a low temperature of about 90 ° C. obtained at the sulfuric acid production plant, and the material of the heat transfer tube 21b is also used. The same thing as Embodiment 1 mentioned above is used.

  That is, nickel (Ni) is 51 to 62.5 mass%, chromium (Cr) is 14.5 to 16.5 mass%, molybdenum (Mo) is 15.0 to 17.0 mass%, and iron (Fe) is 4.0-7.0 mass%, tungsten (W) is 3.0-4.5 mass%, molybdenum (Mo) is 15.0-17.0 mass%, and cobalt (Co) is 1.5- What was contained in each range of 2.5 mass% is used. More precisely, to the above structure, manganese (Mn) and vanadium (V) are added in the range of 0.5 to 1.3% by mass, and carbon (C), phosphorus (P), The total of sulfur (S) and silicon (Si) is 0.2% by mass or less.

Therefore, also in this case, corrosion resistance is exhibited against both ammonia and sulfuric acid, and it can sufficiently withstand use.
By the way, in each said embodiment, although the material of the heat exchanger tube through which the sulfuric acid in an evaporator flows was demonstrated, of course, when there exists a location which contacts sulfuric acid in parts other than a heat exchanger tube, the part is also mentioned above. Material is used. Therefore, you may use the said material also about an evaporator main body. In addition, about the part which does not contact with a sulfuric acid, the material which has corrosion resistance with respect to ammonia is used at least.

DESCRIPTION OF SYMBOLS 1 Evaporator 1a Evaporator main body 1b Heat transfer pipe 3 Turbine 4 Generator 5 Condenser 11 1st heat transfer liquid transfer pipe 12 Heat transfer steam transfer pipe 13 Exhaust steam transfer pipe 14 2nd heat transfer liquid transfer pipe 21 Evaporator 21a Evaporation Main body 21b Heat transfer pipe 22 Turbine 23 Generator 24 Condenser 31 Heat transfer steam transfer pipe 32 Exhaust steam transfer pipe 33 Heat transfer liquid transfer pipe

Claims (1)

An evaporator that has a generator and a turbine that rotates the generator, and that generates a heat medium vapor that is ammonia water or ammonia vapor supplied as a heat medium to the turbine, and a condenser that condenses the exhaust vapor from the turbine An evaporator in a power generation system comprising:
As materials for at least the heat transfer member in the evaporator, nickel (Ni) is 51.0 to 61.5 mass%, molybdenum (Mo) is 15.0 to 17.0 mass%, and chromium (Cr) is 14.5 to 16.5% by mass, iron (Fe) 4.0-7.0% by mass, tungsten (W) 3.0-4.5% by mass and cobalt (Co) 1.5-2.5% by mass An evaporator in a power generation system characterized in that sulfuric acid obtained from a sulfuric acid production process is used as a heat source in the evaporator by using a component included in each of the ranges.

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