JPH05113105A - Power generation while producing carbon dioxide and inert gas - Google Patents

Abstract

PURPOSE:To generate power while producing inert gas and CO2 by liquefying CO inside exhaust gas which is generated from a boiler for generating inert gas with CO2 absorbing solution, and generating power in a steam turbine using the steam in the boiler as a power source. CONSTITUTION:Fuel such as natural gas and kerosene is supplied to a boiler 1 for Generating inert gas through a line (a). The burnt exhaust gas which is generated from the boiler 1 is introduced into CO2 recovery equipment 2 through a line (b). In the same way, the steam which is generated from the boiler 1 is introduced into a steam turbine 5 through a line (e). CO2 inside the burnt exhaust gas is absorbed by using a CO2 absorbing solution in the CO2 recovery equipment 2, and inert raw material gas is obtained through a line (f) as remained gas. The recovered CO2 is introduced into CO2 liquefying equipment 3 through a line (c), and liquefied to be stored in a liquefied CO2 tank 4 through the line (d).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to inert gas (nitrogen gas used for purging facilities of chemical plants) and CO ₂
The present invention relates to a method of simultaneously generating power while producing (carbon dioxide). More specifically, it relates to a method for efficiently generating electric power while producing inert gas and CO ₂ using a boiler for generating inert gas, that is, a kind of cogeneration system.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of eliminating chronic power shortages and environmental protection, cogeneration (thermoelectric power generation) that can simultaneously supply power and heat as a unique power generation facility for buildings, factories, hospitals, etc. Supply systems are receiving attention.

[0003] Similarly, one co in combination with CO ₂ production facility for recovering CO ₂ of kerosene from the boiler combustion exhaust gas as fuel is absorbed by the CO ₂ absorbing solution, and a power generating facility by the steam generated from the boiler Generation systems are known.

By the way, the inert gas is generally a chemical engineer.
Inert used for purging inside equipment in places
Refers to gas. A special burner is used to produce inert gas
And reduces the air required for combustion and is included in the flue gas.
Known as an inert gas generator that can reduce the oxygen content
Has been. In this case, as inert gas
Nitrogen gas and CO obtained directly from inert gas generator
₂Sometimes refers to a mixed gas of₂Is a metal facility
Since it is corrosive to CO, ₂Remove
Often refers to nitrogen gas. Inner in the present invention
Togas also refers to the latter.

[0005]

As described above, the technology for producing inert gas and the system for producing CO ₂ while generating power by the concept of cogeneration are known, but until now, the inert gas and CO ₂ have been produced. There was no known cogeneration system that could simultaneously generate electricity while manufacturing.

[0006]

As a result of studying a system for simultaneously producing CO ₂ and inert gas, the inventors of the present invention have used a boiler using an inert gas generating burner based on the concept of cogeneration, and CO ₂ The present invention has been completed by efficiently combining the production equipment and the power generation equipment to arrive at a kind of cogeneration system that produces electric power while producing CO ₂ and inert gas.

That is, according to the present invention, the steam of the boiler for generating inert gas is used as a heat source and a power source to absorb and recover the CO ₂ in the combustion exhaust gas generated from the boiler by the CO ₂ absorbing liquid and to liquefy the steam. The present invention relates to a cogeneration method for generating electric power while producing inert gas and CO _2, which is characterized in that electric power is generated by a steam turbine using as a power source. Hereinafter, the present invention will be described in detail.

[0008]

FIG. 1 is an example of a process showing the relation of the equipment used in the present invention. In the figure, only the main equipment is shown, and detailed equipment and auxiliary equipment are omitted.

In FIG. 1, a fuel such as natural gas or kerosene is supplied from a line a to an inert gas generating boiler 1. The inert gas generating boiler 1 is a boiler using a special burner, which can suppress the amount of air used for the fuel and suppress the oxygen content in the combustion exhaust gas to a low level, which is already known. .. By using this, the oxygen content in the flue gas depends on the type of fuel, but when an example of burning kerosene is shown, it is kept low at 0.1% (volume basis, the same below), and the remaining The component is CO ₂
Is 12%, steam is 15%, and nitrogen is 72.9%.

The combustion exhaust gas generated from the boiler 1 is guided to the CO ₂ recovery equipment 2 through the line b. Similarly, steam generated from the boiler 1 is guided to the steam turbine 5 by the line e.

[0011] In the CO ₂ recovery facility 2 is CO ₂ absorption in the combustion exhaust gas using the CO ₂ absorbing solution, inert material gas is obtained as a residual gas with recovered by line f. In the above example, 99% of CO ₂ in the combustion exhaust gas is absorbed by the CO ₂ recovery facility 2, so that the composition of the inert raw material gas in the line f is oxygen: 0.11%, CO ₂ :
0.14%, steam: 15% and nitrogen: 84.75%
Becomes By cooling this inert raw material gas with a cooling device (not shown), a high-purity inert gas of nitrogen 99.7% containing oxygen: 0.13% and CO ₂ : 0.17% as impurities is obtained by removing the steam component. .. The recovered CO ₂ is led to a CO ₂ liquefaction facility 3 by a line c through an overhead condenser (not shown) of a CO ₂ absorbing liquid regeneration tower in the CO ₂ recovery facility 2, is liquefied, and is liquefied CO via a line d. ₂ Stored in tank 4.

The CO ₂ recovery facility 2 is usually a cooling device for high temperature combustion exhaust gas, a CO ₂ absorption tower with a CO ₂ absorbing liquid, and a C ₂
It is composed of a regeneration tower for the O ₂ absorbent. An aqueous solution of alkanolamine is used as the CO ₂ absorbing solution. Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, methyldiethanolamine, diisopropanolamine, diglycolamine, and the like, or a mixture thereof, and among them, monoethanolamine is preferably used.

In the present invention, the heat source and power required for liquefying the steam obtained from the inert gas generating boiler by liquefying the CO ₂ in the combustion exhaust gas generated from the boiler by absorbing and recovering the CO ₂ by the CO ₂ absorbing liquid. It has the advantage that it can be used as a source. This is realized in the CO ₂ recovery equipment 2 as follows. That is,
Regeneration of the CO ₂ absorption liquid is performed by the heat of a reboiler (not shown) installed in the lower part of the regeneration tower. In the example of FIG.
As the steam supplied to the reboiler, steam extracted from the steam turbine 5 through the line g is used. The condensed water discharged from the reboiler is returned to the inert gas generating boiler 1 through the line h.

In the CO ₂ liquefaction facility 3, gas C
O ₂ is compressed by a compressor, cooled and liquefied.
In the process used in the present invention, motor driven CO ₂
Although it is preferable to use a compressor and a refrigerating compressor, the compressor may be driven by a turbine that uses steam generated by the inert gas generating boiler 1 as a power source. In that case, the condensed water after driving the turbine is returned to the boiler 1 for generating inert gas.

The steam generated in the boiler 1 for generating inert gas is used as the heat source of the CO ₂ recovery facility (in some cases, the power source of the CO ₂ liquefaction facility 3) as described above, but in the present invention, the rest is the steam turbine. It is used to drive the motor 5 and is generated by the generator 6.
The steam that has driven the steam turbine 5 is guided to the condenser 7 by the line j, cooled, heated by the waste heat of the CO ₂ recovery facility 2 (not shown), and then returned to the inert gas generating boiler 1 by the line k. It

The CO provided in the CO ₂ recovery facility 2
_The low-pressure steam may be used as the heat source of the reboiler of the ₂ absorption liquid regeneration tower. Therefore, when a steam turbine is installed in the CO ₂ liquefaction facility, the exhaust steam or the steam extracted from the turbine may be used.

[0017]

EXAMPLES Hereinafter, an example of balance of main energy and production gas when the process of FIG. 1 is used will be described.

(1) Boiler for generating inert gas 1 Fuel (kerosene) supply rate: 1520 kg / H Combustion exhaust gas temperature: 150 ° C Steam generation rate: 20 T / H Steam pressure: 26 kg / cm ² G Combustion exhaust gas generation rate: 18.0 T / H Combustion exhaust gas composition: oxygen 0.1%, CO ₂ 12%,
Water vapor 15%, nitrogen 72.9%

(2) CO ₂ recovery facility 2 Cooling temperature of combustion exhaust gas during CO ₂ absorption: 60 ° C. Reboiler temperature during CO ₂ recovery: 120 ° C. Steam used in CO ₂ recovery facility 2: 8.3 T / H (Bleaching 3 kg / cm ² G steam from the power generation turbine) Electric power used by the CO ₂ recovery facility 2 (pump, blower, etc.):
CO ₂ recovery rate of 150 kW CO ₂ recovery facility: 99% CO ₂ production: 4796 kg / H inert gas production: 11,780 kg / H Impurities in inert gas: oxygen 0.13%, CO ₂
0.17%

(3) Steam turbine 5 / generator 6 Steam amount used: 20 T / H Power generation amount: 2800 kW

(4) CO ₂ liquefaction facility 3 Electric power used: 750 KW

(5) Other electric power used (boiler, pump, etc.): 100 KW Therefore, 1800 KW of electric power is generated from this device.

[0023]

As described in detail above, according to the present invention, a boiler for generating inert gas is used, and CO ₂
It was possible to provide a method of generating electricity while producing CO ₂ and inert gas, that is, a kind of cogeneration system, by efficiently combining the production equipment and the power generation equipment.

[Brief description of drawings]

FIG. 1 is an example of a process showing the relation of equipment used in the present invention.

Claims (1)

[Claims] 1. A steam for an inert gas generating boiler is used as a heat source and a power source for absorbing and recovering CO ₂ in a combustion exhaust gas generated from the boiler by a CO ₂ absorbing liquid, and liquefying the steam. A method for generating electricity while producing inert gas and CO _2, which is characterized by generating electricity by a steam turbine.