JP2511227B2 - Method for producing power generation fuel and power generation method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fuel for combined cycle power generation and a combined cycle power generation method using the fuel.

[0002]

2. Description of the Related Art At present, as a thermal power generation in Japan, a method using a steam turbine for rotating a turbine with a high-temperature and high-pressure steam generated by a boiler to generate electric power is mainly used. Heavy oil and crude oil are mainly used as the oil fuel for the boiler. Among them, in the case of crude oil burning, low-sulfur content crude oil with a large amount of wax and low SOx generation amount, for example, crude oil from Minas and crude oil from Daqing are preferably used. In addition, recently, a combined cycle power generation method using LNG, which is a good fuel, has been adopted.

Thermal efficiency is about 40% / HHV in power generation by the boiler burning of crude oil or heavy oil and steam turbine.
It is relatively low compared to the standard (HHV: Higher heating value). On the other hand, in combined cycle power generation adopted in LNG-fired combustion, fuel is burned by air compressed by a compressor, or the compressed air is heated by combustion heat, and a turbine is rotated by the high-temperature high-pressure gas. This is a method of generating power, collecting the exhaust gas with a boiler, and operating a steam turbine to generate power again. Thermal efficiency is around 48% / HHV.
It is characterized by high standards.

[0004]

The reserves of petroleum are limited, and the use of petroleum for power generation has come to be restricted internationally from the viewpoint of suppressing the increase in petroleum consumption. In other words, the amount of oil used for power generation must be frozen at present. Therefore, when new equipment is installed due to deterioration of power generation equipment, it is necessary to switch to a power generation method with high thermal efficiency in order to cope with future power demand increase without increasing fuel consumption.

Further, in the combined cycle power generation by LNG, power generation with high thermal efficiency has already been performed, but LNG has a concern about stable supply as compared with crude oil because storage costs high. In Europe and the United States, we already have a record of using crude oil and residual oil as fuel for gas turbines.
A lot of troubles occur due to the impurities contained in them,
It has been pointed out that maintenance costs are higher than when using light oil or LNG. It is said that it is desirable to limit the salt content to 0.5 ppm or less, the sulfur content to 0.05 wt% or less, and the vanadium to 0.5 ppm or less as the impurity content of the oil fuel used for the gas turbine. In particular, salinity and vanadium interact with each other to lower the melting point of the blade metal of the gas turbine and cause ash to stick to the blade. Even low-sulfur content crude oil such as the above-mentioned Minas crude oil or Daqing crude oil used as a boiler burning fuel,
There is a problem that these criteria cannot be satisfied, and they cannot be diverted as they are as gas turbine fuel for combined cycle power generation with good thermal efficiency.

[0006]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a method of using low-sulfur-containing crude oil as a fuel for combined cycle power generation with high thermal efficiency. As a result, among the fuels used in combined cycle power generation, gas Although a fuel with a low content of impurities is required for turbines, the restrictions on the content of impurities in the boiler are relatively lenient, and low-sulfur content crude oil is generally waxy, and the content of heavy metals such as vanadium is also low. Gas turbine fuels and exhaust gas that meet all the required criteria by separating these low sulfur content crude oils into low boiling fractions and high boiling fractions by simple desalination and distillation. The present invention has been completed, paying attention to the fact that a fuel for a heat boiler can be obtained.

That is, the first gist of the present invention is that a low-sulfur content crude oil having a salt content adjusted to 0.5 ppm or less is subjected to atmospheric distillation or vacuum distillation to obtain a low-boiling fraction having a sulfur content of 0.05% by weight or less. A method for producing a fuel for power generation, characterized in that it is separated into a gas turbine fuel for combined cycle power generation and a boiler fuel consisting of a high boiling fraction having a sulfur content of more than 0.05% by weight. The second gist of the present invention is to subject a low-sulfur content crude oil having a salt content adjusted to 0.5 ppm or less to atmospheric distillation or vacuum distillation to obtain a low-boiling fraction having a sulfur content of 0.05% by weight or less and a sulfur content. Is separated into a high boiling point fraction exceeding 0.05% by weight, the low boiling point fraction is used as a gas turbine fuel for combined cycle power generation, and the high boiling point fraction is used as a boiler fuel. Do It is an electrical method.

[0008]

EXAMPLE A method for producing a fuel for combined cycle power generation according to the present invention and a method for combined cycle power generation using the fuel will be described below with reference to FIG. 1, and the operation of the present invention will be clarified. In FIG. 1, only main equipment is shown and auxiliary equipment is omitted. Needless to say, as the low-sulfur content crude oil used in the present invention, one having as low a sulfur content as possible is preferable because the desulfurization process of combustion exhaust gas can be simplified, but usually the sulfur content is 1% by weight or less, more preferably Crude oil up to 0.9% by weight is used.
Examples of such crude oil include the crude oil produced in Minas and the crude oil produced in Daqing mentioned above, which are rich in wax. The amount of vanadium contained in such crude oil is usually 0.4 to 0.5.
It is ppm. Minas crude oil is particularly preferable as the low-sulfur content crude oil because it has a sulfur content of about 0.1% by weight or less.

In the present invention, such a low-sulfur content crude oil is subjected to a desalting treatment step 1 so that the salt content is 0.5 ppm.
Adjust as follows. As the desalting method, the method usually used for desalting crude oil can be directly applied. That is, if water is added to the crude oil to wash it and the aqueous layer is separated, the salt content decreases. In ordinary petroleum refining, the salt content is set to 3 ppm or less, but the salt content can be easily set to 0.5 ppm or less by repeating the water washing desalting method.

The low-sulfur content crude oil having a salt content adjusted to 0.5 ppm or less is subjected to an atmospheric distillation step 2 or a vacuum distillation step 3.
Thus, a low boiling fraction having a sulfur content of 0.05% by weight or less and a high boiling fraction having a sulfur content of more than 0.05% by weight are separated. Either one of the both distillations may be performed, or the fraction having a high boiling point separated by the atmospheric distillation may be further distilled under reduced pressure as shown in FIG. Depending on the crude oil used, the boiling point fraction having a sulfur content exceeding the boundary value of 0.05% by weight and the fraction of the fraction differ, but in the case of the above-mentioned Minas crude oil, a light oil fraction (converted to a normal pressure boiling point of about 340 to 460 ° F or less) to a gas fraction (both 460 to 650 ° F) or less and a boiling point fraction higher than that to obtain a sulfur content of 0.0
Approximately 40% of low boiling point fraction of 5% by weight, sulfur content of 0.05
High-boiling fractions in excess of weight% are obtained in a proportion of about 60%.
Moreover, almost no heavy metal such as vanadium is detected in the low boiling fraction, and it is suitable as a gas turbine fuel for combined cycle power generation.

In a typical example of the above-mentioned crude oil produced by Minas, when crude oil having a salt content adjusted to 0.5 ppm or less by a desalting treatment is separated into a fraction having a boiling point of 650 ° F. Fraction below 4 ° F is 43.2% by volume
The sulfur content was 0.033% by weight, and vanadium was not detected, so that a fuel for gas turbine of combined cycle power generation was obtained. The residual oil (REDUCED-CRUDE, boiling point 650 ° F or higher, specific gravity 26.5 ° API, pour point 106 ° F) after collecting the low boiling fraction has a sulfur content of about 0.15% by weight and is a good quality heavy oil. Medium low, each content of dnadium / nickel / iron is about 1/15 / 10p
It was pm and could be used as a boiler fuel without any trouble.

In the present invention, when the proportion of high-boiling fraction (or residual oil) having a sulfur content of more than 0.05% by weight is large depending on the low-sulfur content crude oil to be used, this is further separated to obtain the gas turbine. It is also possible to collect fuel that meets the usage standards. As a method for separating such residual oil, a known supercritical solvent extraction / separation step 4 (for example, JP-A-57-31989, JP-A-59-170191) using a high temperature / high pressure solvent is used. Can be used.

[0013]

INDUSTRIAL APPLICABILITY As described in detail above, unlike the conventional case where a low-sulfur content crude oil is used for boiler-fired power generation, in the present invention, a desulfurized low-sulfur content crude oil is subjected to atmospheric distillation or vacuum distillation. By separating the low boiling point fraction and the high boiling point fraction with, a gas turbine fuel and boiler fuel satisfying all the required criteria can be obtained. By using these fuels for combined cycle power generation, it is possible to generate power at about 48% of high thermal efficiency as compared to about 40% of thermal efficiency when the entire amount is burned by a boiler and power is generated by a steam turbine. It is extremely advantageous from the viewpoint of preventing global warming by CO ₂ .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a process for producing a fuel for combined cycle power generation from crude oil containing low sulfur to which the present invention is applied.

Claims (2)

(57) [Claims] 1. A combined cycle power generation system comprising a low boiling point distillate having a sulfur content of 0.05% by weight or less by atmospheric distillation or vacuum distillation of a low sulfur content crude oil having a salt content adjusted to 0.5 ppm or less. A method for producing a fuel for power generation, which comprises separating a gas turbine fuel and a boiler fuel composed of a high boiling fraction having a sulfur content of more than 0.05% by weight. 2. A low-sulfur-containing crude oil having a salt content adjusted to 0.5 ppm or less is subjected to atmospheric distillation or vacuum distillation to a low-boiling fraction having a sulfur content of 0.05% by weight or less and a sulfur content of 0. A high boiling point fraction exceeding 05% by weight is separated, and the low boiling point fraction is used as a fuel for a gas turbine for combined cycle power generation, and the high boiling point fraction is used as a fuel for a boiler to generate electricity. How to generate electricity.