JPH09195721A - Combined cycle cenerating facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize heat energy by heating a feed water heater by low boiling point fraction and/or high boiling point fraction after distillation, in a facility in which low boiling point fraction is used for fuel of a gas turbine and high boiling point fraction is used for fuel of a boiler for a steam turbine. SOLUTION: A crude oil feed pump 2 forcedly feeds crude oil in a crude oil tank 1 to a crude oil heating furnace 7 and a distillation tower 8 through a crude oil feed line 21, and in this case, crude oil preheaters 3-6 recover heat respectively from low boiling point fraction or high boiling point fraction drawn from the distillation tower 8 and heat in oder crude oil, so as to lighten the burden of the crude oil heating furnace 7. The distillation tower 8 is constituted into a system improving separation rate by contacting the low boiling point fraction with generated vapor of crude oil, and the low boiling point fraction drawn from the distillation tower 8 and cooled and condensed by a condenser 9 is fed as gas turbine fuel. Meanwhile, the high boiling point fraction drawn from the distillation tower 8 is forcedly fed to a boler fuel tank 14 through a liquid line 24.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an oil-fired gas turbine combined cycle power generation facility.

[0002]

2. Description of the Related Art At present, thermal power generation in Japan mainly uses a method in which a steam turbine is rotated by high-temperature and high-pressure steam generated by a boiler to generate power. As the boiler fuel, heavy oil and crude oil are mainly used. Among them, in the case of crude oil burning, low-sulfur content crude oil containing a large amount of wax and having a small amount of SO _x , for example, Minas crude oil or Daqing crude oil is preferred. In addition, recently, combined cycle power generation equipment using LNG, which is a high-quality fuel, has been adopted.

In the boiler burning of crude oil or heavy oil and power generation by a steam turbine, the thermal efficiency is relatively low at around 40% / HHV standard (HHV: high heating value). On the contrary,
Combined cycle power generation used in LNG-fired is a method of burning fuel in a gas turbine, reburning the high-temperature exhaust gas in a boiler, operating a steam turbine, and generating power again (so-called exhaust gas reburn type), and thermal efficiency is high. Around 48% / HHV standard, dramatically improving.

[0004] For this reason, in recent years, from the viewpoint of suppressing an increase in petroleum consumption, it has been required to switch to a power generation method with higher thermal efficiency, and the development of the combined cycle power generation has been strongly desired. However, in conventional LNG combined cycle power generation, LNG is expensive to store, and when supplying LNG to oil-fired thermal power, burying pipelines is expensive.

On the other hand, a so-called oil-fired gas turbine combined cycle power generation using crude oil as a fuel
In some cases, the practice was carried out in Europe and the United States. However, there was a problem that many troubles occurred due to impurities contained in crude oil and maintenance cost was increased. In this respect, practical use was difficult. This is because the salt, vanadium, and sulfur contained in the crude oil interact with each other to become a substance having a low melting point in the gas turbine, adhere to the blade, and cause corrosion of the blade.

Therefore, as a fuel for a gas turbine, a standard in which the content concentration of salt and vanadium is 0.5 ppm or less is generally adopted. However, such as the crude oil from Minas and the crude oil from Daqing mentioned above. Even low-sulfur content crude oil could not meet these standards, and could not be used as it was as a gas turbine fuel for combined cycle power generation with good thermal efficiency. Therefore, as a result, it has been difficult to commercialize oil-fired gas turbine combined cycle power generation using crude oil as fuel for gas turbines.

[0007]

The applicant has proposed, for example, Japanese Patent Application No. Hei.
287504 (JP-A-6-207180)
Desalted crude oil is distilled at a specified concentration to separate it into a low boiling fraction and a high boiling fraction, and the low boiling fraction is used as fuel for a gas turbine, while the high boiling fraction is used for a steam turbine. An oil-fired gas turbine combined cycle power generation method using crude oil distillation technology, which is used as fuel for a boiler, has been proposed and is being put into practical use. However, in this power generation method, since the crude oil after distillation (that is, the above-mentioned low-boiling fraction and high-boiling fraction) has a considerably high temperature, it has been demanded to effectively utilize the thermal energy.

On the other hand, the steam cycle in this type of power generation equipment has been improved by various improvements to improve the efficiency, and generally, a plurality of steam turbines of high pressure, medium pressure and low pressure and a plurality of places of each turbine are generally used. Each of the steam generators has a complicated structure including a large number of extracted feed water heaters that sequentially heat boiler feed water with the steam extracted, and there is a limit to further improvement in thermal efficiency.

Therefore, the present invention is an oil-fired gas turbine combined cycle power generation facility utilizing crude oil distillation technology, in which the thermal energy of distillation is effectively utilized.
The objective is to provide a combined cycle power generation facility that enables more efficient power generation.

[0010]

In order to achieve the above object, in the combined cycle power generation facility according to claim 1, crude oil is distilled at a predetermined temperature to separate it into a low boiling fraction and a high boiling fraction. In the combined cycle power generation facility using the low boiling fraction as a fuel for a gas turbine and the high boiling fraction as a fuel for a steam turbine boiler, the low boiling fraction after distillation or / and A feed water heater for recovering heat from the high boiling point fraction to heat the feed water to the boiler is provided.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a fuel supply system in the combined cycle power generation facility of this example, and FIG. 2 shows a configuration of a power generation system in the combined cycle power generation facility.

As shown in FIG. 1, the fuel supply system of this power generation facility has a crude oil tank 1, a crude oil supply pump 2, crude oil preheaters 3 to 6, a crude oil heating furnace 7, a distillation tower 8, as main components. Condenser 9, gas turbine fuel supply pump 10, reflux pump 11, gas turbine fuel tank 12, boiler fuel supply pump 13, boiler fuel tank 14, feed water heater 1
5 and 16 are provided.

The crude oil tank 1 stores crude oil,
As this crude oil, it is preferable to use a desulfurized low-sulfur crude oil. As the low-sulfur crude oil, it is needless to say that the sulfur content is as small as possible because the desulfurization step of the exhaust gas can be simplified, but usually the sulfur content is 1% by weight or less, more preferably 0.5% by weight or less. Less than wt% crude oil is used.

Examples of such crude oil include the crude oil from Minas and the crude oil from Daqing mentioned above. Since most of the sulfur content contained in crude oil is separated by distillation described below, it is not always necessary to use the low-sulfur crude oil as described above as the crude oil of the present invention.

Further, the salt content contained in the crude oil tends to remain on the high boiling point fraction side due to the distillation in the distillation column 8, and depending on the concentration condition of the distillation, the salt content of the low boiling point fraction may be the above-mentioned standard value (0 0.5 ppm) or less, the crude oil of the present invention does not necessarily have to be desalted.

When the desalination treatment is carried out in the same equipment, a heating means for heating crude oil to about 80 to 150 ° C. is provided in advance and, for example, a well-known desalting means such as a disorouter is used if necessary. A plurality of stages may be provided. This dissoluter mixes heated crude oil and fresh water,
Water droplets are aggregated and separated by applying an electrostatic voltage of about 10,000 volts.In order to reduce the viscosity of crude oil and to facilitate separation due to the difference in specific gravity between water and crude oil, pre-heat crude oil as described above. Is preferred. In addition, the above-mentioned diso router is arranged on the way of the crude oil supply line 21 for feeding the crude oil from the crude oil tank 1 to the crude oil heating furnace 7, and some of the crude oil preheaters 3 to 6 are heated for the desalination treatment. It can also function as a means.

The crude oil supply pump 2 sends out the crude oil in the crude oil tank 1 and pressure-feeds it to the crude oil heating furnace 7 and further to the distillation column 8 via the crude oil supply line 21. In this case, the crude oil heating furnace 7 is composed of crude oil, light oil, kerosene, naphtha, L prepared separately from crude oil in the crude oil tank 1 or power generation fuel.
The crude oil sent to the distillation column 8 by burning PG or the like is heated to a predetermined distillation concentration. The distillation temperature (the temperature of crude oil at the inlet of the distillation column 8) is adjusted according to the properties of the crude oil so that the vanadium, salt or sulfur content of the low boiling point fraction that serves as the fuel for the gas turbine becomes a desired value. The temperature may be determined according to the condition, but it is, for example, about 340 ° F to 650 ° F.

Crude oil preheaters 3, 4 or crude oil preheaters 5, 6
In this case, heat is recovered in two stages from the gas (i.e., low-boiling fraction) derived from the top of the distillation column 8 or the liquid (i.e., high-boiling fraction) derived from the bottom of the distillation column 8. And a heat exchanger for sequentially heating the crude oil before being sent to the crude oil heating furnace 7, thereby increasing the heating efficiency of the crude oil and reducing the burden on the crude oil heating furnace 7.

In the distillation column 8, in this case, the low-boiling-point fraction derived from the top of the column by the reflux pump 11 and the reflux line 22 is returned as a liquid, and comes into countercurrent contact with the generated vapor of crude oil to separate it. Is a distillation column of a method of increasing the temperature (so-called rectification column), and specifically, for example, a bubble column, a perforated plate column, or a packing column can be used.

The condenser 9 is connected to the distillation column 8 by the liquid line 23.
Is a tube type heat exchanger for finally cooling and condensing a gas (that is, a low-boiling fraction) derived from the top of the column. In this case, gas that has not been completely condensed (off-gas) is discharged from the top. You. Then, the low boiling point fraction of the crude oil condensed in the condenser 9 is extracted from the bottom, a part thereof is returned to the distillation column 8 by the reflux pump 11 and the reflux line 22, and the rest is gas turbine fuel. The turbine fuel supply pump 10 sends the gas to the gas turbine fuel tank 12.

The boiler fuel supply pump 13 pumps the liquid (that is, high boiling point fraction) derived from the bottom of the distillation column 8 to the boiler fuel tank 14 through a liquid line 24. The feed water heaters 15 and 16 heat the gas (ie, a low-boiling fraction) derived from the top of the distillation column 8 or the liquid (ie, a high-boiling fraction) derived from the bottom of the distillation column 8. It is a heat exchanger that collects and heats boiler feedwater sent to a boiler 35 described later.

Next, the power generation system of this power generation facility, as shown in FIG.
A gas turbine 34 including a compressor 32 and a combustor 33;
A boiler 35, a steam turbine 36, a condenser 37, and an economizer 38 are provided. Here, the gas turbine 34 causes the combustor 33 to contact the gas turbine fuel supplied from the gas turbine fuel tank 12 via the supply line 41 with the air compressed by the compressor 32 and burn the gas turbine fuel.
This is a well-known type that rotates the output shaft by the expansion of the combustion gas in the turbine 31 to generate electric power, and in this case, in order to form an exhaust gas reburn type combined cycle, exhaust gas after combustion (residual oxygen concentration of about 11% to 15% Temperature of about 580 ° C.) is supplied to the boiler 35 via the exhaust gas line 42.

The boiler 35 is, for example, a Stirling boiler and has a convection heat transfer section 35a. The boiler 35 is supplied with the high-boiling fraction in the boiler fuel tank 14 through the supply line 43 as fuel, and the smoke exhausted from the boiler 35 via the smoke exhaust line 44 is omitted from the drawing. After passing through the denitration device and the dust collecting device, the heat is recovered by the economizer 38 and guided to a chimney (not shown) to be released to the atmosphere. Depending on the properties of the crude oil, a desulfurizer for removing sulfur (especially sulfur dioxide) from the flue gas may be provided. In addition, economizer 38
Is a heat exchanger for heating the boiler feed water by the heat of the flue gas of the boiler 35 for improving the heat efficiency of the steam cycle.

Although detailed illustration is omitted because it is complicated in FIG. 2, as a steam cycle system including the steam turbine 36, a so-called reheat cycle is formed as in the configuration example of FIG. 3 described later. In order to achieve high efficiency, a high efficiency, medium pressure, low pressure, etc. are provided with multiple stages of steam turbines, and a plurality of extraction feed water heaters are provided to form a so-called regeneration cycle to ensure high thermal efficiency. Naturally, it is preferable to have a configuration. Then, in the case of this example, the feed water heaters 15 and 16 shown in FIG. 1 (not shown in FIG. 2).
Also, the feed water sent from the condenser 37 to the boiler 35 is heated to further increase the thermal efficiency of the steam cycle.

That is, the steam cycle in the power generation equipment of the present invention is constructed in detail as shown in FIG. 3, for example, which will be described below. Here, a high-pressure turbine 53, a medium-pressure turbine 56, and low-pressure turbines 58 and 59, which will be described later, function as the steam turbine 36 in FIG.

In FIG. 3, the high-pressure steam generated by being heated by the boiler 35 is first introduced into the high-pressure turbine 53 through the piping line 52, expands to perform the work of driving the turbine blades, and returns to the boiler 35 through the line 54. After being heated and reheated, the medium pressure turbine 5
Introduced to 6 and work again. The low-pressure steam expanded by the work performed by the medium-pressure turbine 56 is guided by a line 57, and is branched and introduced into two low-pressure turbines 58 and 59 provided in parallel in this case.
Work further at 8,59. Each low-pressure turbine 5
The steam expanded at the work at 8,59 is introduced into the condenser 37 whose internal pressure is made negative by the line 60 and condensed.

The condensed water in the condenser 37 is sent out by the pump 62 as boiler feed water, and is first heated by the heater 63 by the heat of the steam J flowing out from the bearing portion of each turbine. Thereafter, this boiler feed water is sequentially heated by a large number of extraction feed water heaters 71 to 78 and feed water heaters 15 and 16, and finally sent to the boiler 35 by a line 64.

Here, the extraction feed water heaters 71, 72, 7
3, 74 is a so-called surface type extraction water heater,
The boiler feedwater is sequentially heated by a part of the steam extracted from the four stages of the low-pressure turbines 58, 59 by the lines 81, 82, 83, 84, respectively. After the steam extracted by the line 81 exits the bleed water heater 71,
It is introduced into the condenser 37 by the line 91 and condensed to become a part of boiler feed water.

The steam extracted through the line 82 exits the extraction feed water heater 72, and is then mixed into the boiler feed water at the inlet side of the extraction feed water heater 73 through the line 92 to become a part thereof. The steam extracted by the lines 83 and 84 also exits the bleed water heaters 73 and 74 and is sent to the bleed water heater 72 or 73 by lines 93 and 94, respectively. At the inlet side of the feed water heater 73, it is mixed with the boiler feed water and becomes a part thereof.

The bleed air feed water heater 75 is a so-called mixed bleed air feed water heater, which mixes a part of the steam extracted by the line 85 from the position of the rear stage of the intermediate pressure turbine 56 with the boiler feed water. This heats the boiler feed water. The boiler feedwater after the mixing and heating exits the bleed water heater 75 and is then introduced into the bleed water heater 76 via a line 95.

Further, extraction water heaters 76, 77, 78
Is a surface-type bleed air / water heater, and is a medium-pressure turbine 56
The boiler feedwater is sequentially heated by a part of the steam extracted from the middle stage and the latter stage of the high pressure turbine 53 by the lines 86, 87 and 88, respectively. Here, after the steam extracted by the line 86 exits the bleed water heater 76, the steam is extracted by the line 96 to the bleed water heater 7.
5 and mixed into the boiler feedwater to form part of it.

Further, the steam extracted by the lines 87 and 88 also leaves the extraction feed water heaters 77 and 78, and then the line 9
Extraction water heater 76 or 77 according to 7 or 98, respectively
And is finally introduced into the bleed water heater 75 and mixed with the boiler water to become a part thereof. In addition, line 9
2, 95 are provided with pumps 99, 100 for boosting and feeding the boiler feed water, and water W is appropriately replenished in the pump 100.

During the steam cycle, the feed water heaters 15 and 16 are connected to the inlet side of the extraction feed water heater 71 and the inlet side of the extraction feed water heater 72, respectively, as shown in FIG. The boiler feed water is heated by the residual heat of the crude oil (low-boiling fraction, high-boiling fraction) after the distillation described above. Although illustration of the economizer 38 shown in FIG. 2 is omitted in FIG. 3, the economizer 38 is also connected to the boiler feed water heating line in the same manner as the feed water heaters 15 and 16, and The heat of the flue gas of 35 heats the boiler feed water to contribute to the improvement of thermal efficiency.

The boiler feed water concentration is, for example, usually about 33 ° C. on the outlet side of the condenser 37, about 34 ° C. on the outlet side of the heater 63, and 64 ° C. on the outlet side of the extraction feed water heater 71. About 84 ° C at the outlet side of the extraction water heater 72
Approximately 120 ° C. at the outlet side of the bleed air feed water heater 73, usually about 140 ° C. at the outlet side of the bleed air feed water heater 74, and finally 2 at the outlet side of the bleed air feed water heater 78.
The temperature is set to about 83 ° C. and sent to the boiler 1.

According to the combined cycle power generation facility configured as described above, a fuel (low boiling point fraction) suitable for the gas turbine 34 is continuously supplied by distillation of crude oil,
A more efficient power generation utilizing the advantages of the combined cycle power generation can be realized while avoiding the problems such as the corrosion of the blade metal of the gas turbine 34 due to the impurities as described above. That is, in FIG. 1, the crude oil tank 1
The crude oil sent from the crude oil supply pump 2 by the crude oil supply pump 2 is heated to, for example, about 270 ° C. by the crude oil preheaters 3 to 6, and finally, in this case, by the crude oil heating furnace 7 independently provided, a predetermined distillation temperature (for example, (360 ° C.).

If the distillation temperature is maintained at the predetermined distillation temperature in this way, the vanadium and salt content concentrations of the low boiling point fraction (that is, gas turbine fuel) derived from the top of the distillation column 8 are reduced. , Can be easily maintained below the standard value of 0.5 ppm (wt.), And the sulfur content is 0.5 to 0.
05 wt. % Or less. That is, most of the heavy metals remain in the high-boiling fraction above 900 ° F in the case of atmospheric distillation, and 420 ° C (7
Since it remains in the high boiling fraction above about 88 ° F), most of these impurities remain in the high boiling fraction side in this case,
It will be included in the boiler fuel sent to the boiler fuel tank 14. In the boiler 35, since heavy oil and the like are conventionally burned, the fuel containing such impurities can be operated without any problem.

Thus, the fuel having a sufficiently low impurity concentration is continuously supplied from the gas turbine fuel tank 12 to the gas turbine 34, and the high temperature exhaust gas discharged from the gas turbine 34 is introduced into the boiler 35 and reburned. As a result, highly efficient combined cycle power generation using crude oil that can be easily stored can be operated reliably without causing troubles due to impurities in the crude oil.

In this example, the feed water heaters 15 and 16
However, during the steam cycle, for example, as shown in FIG. 3, the inlet side of the extraction air feed water heater 71, and the extraction air feed water heater 72.
The boiler feed water is heated by the residual heat recovered from the crude oil (low boiling point fraction, high boiling point fraction) after distillation, which is connected to each of the inlet sides of the boiler.

For example, in the case of a power generation facility with a gas turbine output of about 130 MW and a steam turbine output of about 560 MW, the flow rate of the low boiling point fraction in the fuel supply system of FIG. 1 is about 40,000 kg / H, Since the concentration of the low boiling point fraction at the inlet of the feed water heater 15 is about 90 ° C., it is possible to recover the heat quantity of about 2 × 10 ⁶ kcal / H by the feed water heater 15, and in this case, the high boiling point fraction. The flow rate of the minute is about 60,000 kcal / H, and the feed water heater 1
Since the temperature of the high boiling point distillate at the inlet of 6 is about 200 ° C, the feed water heater 16 can recover a heat amount of about 5 × 10 ⁶ kcal / H, and these heat amounts are used to raise the boiler feed water. It

Therefore, in this case, the extraction water heater 7
1 and the load of the extraction water heater 72 are reduced, and the line 8
Since the amount of bleed air from 1 and the line 82 can be reduced, the output of the low pressure turbines 58 and 59 can be increased by that amount, and as a result, the thermal efficiency of the steam cycle is improved beyond the conventional limit. As well as
Effective use of energy is achieved.

That is, as described above, the steam cycle of this type of thermal power generation equipment has hitherto been subjected to various improvements for higher efficiency, and as described above, a plurality of high pressure, medium pressure, and low pressure are used. Of the steam turbine and a large number of extraction feed water heaters for sequentially heating the boiler feed water by the steam extracted from a plurality of points of each turbine, which has a limit in improving the thermal efficiency. However, when the feed water heaters 15 and 16 that heat the feed water by utilizing the residual heat of distillation for fuel production are provided as in this example, the configuration of equipment such as a boiler, a turbine, or an extraction feed water heater is provided. It is possible to further improve the thermal efficiency without remodeling, and the residual heat of the distillation can be effectively used.

[0042]

According to the combined cycle power generation facility of the present invention, crude oil is distilled at a predetermined temperature to separate a low boiling point fraction and a high boiling point fraction, and the low boiling point fraction is used as a fuel for a gas turbine. In the combined cycle power generation facility using the high boiling point fraction as a fuel for a steam turbine boiler, the low boiling point fraction after distillation or /
And a feed water heater for recovering heat from the high boiling fraction and heating the feed water to the boiler.

Therefore, in the steam cycle including the steam turbine, the load on the extraction feed water heater can be reduced, and the amount of extraction air from the steam turbine can be reduced. Therefore, the output of the steam turbine can be increased by a corresponding amount. As a result, the thermal efficiency of the steam cycle is improved beyond the conventional limit, and the energy is effectively used.

Therefore, the fuel (low boiling point fraction) suitable for the gas turbine is continuously supplied to avoid the problems such as the corrosion of the blade metal of the gas turbine due to the impurities as described above, while performing the combined cycle. Highly efficient power generation that takes advantage of power generation can be realized with higher efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a fuel supply system of a combined cycle power generation facility which is an example of the present invention.

FIG. 2 is a diagram showing a power generation system of the combined cycle power generation facility.

FIG. 3 is a diagram showing a detailed configuration example of a steam cycle of the combined cycle power generation facility.

[Explanation of symbols]

 1 Crude oil tank 7 Crude oil heating furnace 8 Distillation tower 15,16 Feed water heater 34 Gas turbine 35 Boiler 36 Steam turbine 37 Condenser 53 High pressure turbine (steam turbine) 56 Medium pressure turbine (steam turbine) 58,59 Low pressure turbine (steam) Turbine)

Claims (1)

[Claims] 1. A crude oil is distilled at a predetermined temperature to separate it into a low boiling fraction and a high boiling fraction, the low boiling fraction is used as a fuel for a gas turbine, and the high boiling fraction is a steam turbine. In a combined cycle power generation facility used as fuel for a boiler for boilers, a feed water heater for heating the feed water to the boiler by recovering heat from the low boiling point fraction and / or the high boiling point fraction after being distilled is provided. Combined cycle power generation facility characterized by.