JPS63315878A - Gas separator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for supplying high-purity product gas through cryogenic separation, and in particular to cooling and liquefying raw material gas by utilizing the cold generation effect of an expansion turbine. This invention relates to a gas separation device that performs rectification separation.

[Conventional technology]

Figure 2 shows a system diagram of a conventional carbon monoxide recovery device using the cryogenic separation method. In the figure, a raw material gas whose main component is carbon monoxide (hereinafter referred to as CO) containing hydrogen, nitrogen, methane, etc. enters the heat exchangers 1 and 2 from a conduit 15 at a pressure of about 35 Kp/ciG, and returns at a low temperature. Approximately -190 depending on gas
It is cooled to about 0.degree. C. and enters the low-temperature separation a3 through the n1 conduit 17. Here, uncondensed gas (hereinafter referred to as hydrogen gas) whose main components are hydrogen and nitrogen, which are lower boiling point components than CO, is separated, passed through a conduit 18, and slightly recovered in temperature in a heat exchanger 2, and then passed through a conduit 19. It is further expanded in the expansion turbine 5 to approximately 15 Ky/dG. Due to this expansion, hydrogen gas becomes approximately -195
℃, and through conduit addition and heat exchanger 2.1, it becomes a cold source that lowers the raw material gas to a predetermined cooling temperature, and after recovering it to room temperature, it is sent out from conduit n, hydrogen. Used as a gas.

The liquefied fraction containing CO as a main component separated in the low-temperature separator 3 passes through the conduit U and is reduced in pressure to approximately atmospheric pressure through the valve 101, and is then reduced to approximately atmospheric pressure through the conduit 5. C from conduit 3 via heat exchanger 2
o Supplied to rectification column 4. Here, the CO is rectified and separated from the top of the rectification column 4 through a conduit n and a heat exchanger 1. High purity product CO gas, which has been recovered to room temperature, is supplied from between the pipes through the pipes. In addition, fuel gas mainly composed of methane is supplied from the lower part of the column to a conduit A and a heat exchanger 1. It is sent out from the conduit. As a cold source for the Co rectification column 4, a part of the product CO gas is raised to about 8 KP/crlo in the CO compression chamber 6, and is sent to the heat exchanger l through the conduit 31. The product CO gas cooled by the low-temperature return gas in the heat exchanger 1 passes through the conduit ℃ to the Co rectification column 4.
is sent to the lower part of fL, where the methane gas is evaporated and the product CO gas itself is conversely liquefied. then liquefied n
The product CO gas is sent to the upper part of the column through a conduit, and the pressure is reduced to near atmospheric pressure by a valve 14.Then, it is supplied as a cold source to the Co rectification column 4, and is liquefied to rectify the gas rising in the column. Used for business purposes. Further, when adjusting the outlet temperature of the expansion turbine 5, the valve 11 is gradually opened or closed using the remote control device 08. Note that when the valve 11 is gradually closed, the pressure on the primary side of the valve 11 increases, so the valve is gradually opened according to the setting value of the pressure indicator controller α
Adjust the primary side pressure of 1 to a constant value. Note that related devices of this type include, for example, Japanese Patent Application Laid-Open No. 59-24168.
The number is listed.

[Problem that the invention seeks to solve]

According to the above-mentioned conventional technology, the flow rate and composition of the design conditions are used as the basis for designing the product CO gas purity/recovery rate and by-product hydrogen gas properties/equipment specifications.

Stable and high purity product C even when the raw material gas fluctuates by 1 til
Not much consideration was given to the supply of O gas.

Therefore, when the feed gas flow rate decreases, the heat load on the heat exchanger becomes smaller than the design-based heat load, but the hydrogen gas temperature at the expansion turbine outlet does not change compared to the design conditions, so the heat exchanger cold end The temperature difference between the two sides becomes small, and the raw material gas is cooled to a predetermined temperature or higher. This improves the purity of hydrogen gas, but the liquefied fraction in the low-temperature separator contains n.
Although it has a lower boiling point than CO, the proportion of nitrogen, which has a boiling point very close to that of CO, increases and enters the product CO gas without being passed through the CO rectification column, reducing the purity of the product CO gas. There was a problem.

An object of the present invention is to provide a gas separation device that automatically maintains a raw material gas at a predetermined cooling temperature even when the raw material gas flow rate fluctuates, and supplies a product CO gas with stable product gas purity. .

[Means for solving problems]

The above purpose is to measure the raw material gas temperature at the heat exchanger outlet with a temperature controller and automatically adjust the expansion turbine inlet pressure when the raw material gas flow rate fluctuates and the raw material gas is cooled to a predetermined temperature or higher. This is achieved by adjusting the hydrogen gas expansion turbine exit temperature to create a temperature difference that corresponds to the load on the heat exchanger.

[For production]

When the raw material gas flow rate fluctuates, for example, when the raw material gas flow rate decreases, the heat load on the heat exchanger becomes smaller than the design-based heat load. The heat load Q of the heat exchanger and the heat transfer surface A,
The relationship between the overall heat transfer coefficient U and the temperature difference △T is Q=U-A・△T
It is. Considering that the heat transfer surface A is constant and the overall heat transfer coefficient U is also almost constant, as mentioned above, if Q is small, △T is also the same (smaller).Here, the hydrogen gas expansion turbine inlet pressure is Unless the outlet temperature is increased by lowering the temperature, the hydrogen gas temperature at the expansion turbine outlet is constant, so if the temperature difference △T becomes small, this means that the raw material gas temperature has fallen too much below the predetermined cooling temperature, and the product CO gas purity becomes worse.

However, temperature controllers installed in the raw gas line from the low-temperature separator or heat exchanger to the low-temperature separator and in the hydrogen line from the low-temperature separator determine that when the raw gas temperature drops below a predetermined cooling temperature, the expansion turbine inlet The pressure control valve of the hydrogen gas line is gradually closed, and the pressure at the expansion turbine inlet is low (adjusted).The hydrogen gas temperature at the expansion turbine outlet is kept high by 20, and the temperature difference △T of the heat exchanger is small. Since the cold end temperature will rise even if
Ru.

〔Example] DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In the figure, the overall configuration of this device is a heat exchanger 1.2, a low temperature separator 3. Co rectification column 4. Expansion turbine 5, Co compressor 6. Pressure indicating controller7. Pressure control valve 11. Temperature controller 1
3. Valve +0.12.14. It consists of conduits 15 to 35, etc.

The feed gas enters the heat exchangers 1 and 2 from the conduit 15 at a pressure of about 35°C/alG, and is cooled by a low temperature return gas such as hydrogen gas cooled by the expansion turbine 5.

If the raw material gas flow rate fluctuates and an excessive load is applied to the heat exchanger 1.2, the raw material gas will not be cooled to a predetermined temperature or higher unless the inlet pressure of the expansion turbine 5 is changed. If the raw gas is cooled too much beyond the set value of the temperature controller 13 installed in the low-temperature separator 3, the temperature controller 13 automatically closes the inlet pressure control valve 11 of the expansion turbine 5. Closed n expansion turbine μ mouth pressure is low (adjusted).

As the inlet pressure of the expansion turbine 5 is adjusted, 7 is automatically set by the pressure indicating controller σ, and the valve 12 is gradually opened.
Adjust the primary pressure of No. 1 to a constant value. Since the initial humidity is high, the raw material gas is automatically adjusted to a predetermined temperature.

According to this embodiment, even if the raw material gas flow rate fluctuates, the raw material gas can be automatically kept at a predetermined cooling humidity and the product CO gas purity can be stably maintained.

〔Effect of the invention〕

According to the present invention, even if the raw material gas flow rate fluctuates, the final cooling temperature of the raw material gas is automatically controlled and cooled to a predetermined temperature, so product CO gas of stable purity can be supplied, and the product This has the effect of allowing stable operation to continue without adversely affecting downstream equipment that uses CO gas.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a carbon monoxide recovery apparatus showing an embodiment of the present invention, and FIG. 2 is a system diagram of a carbon monoxide recovery apparatus according to a conventional method. 1.2... Heat exchanger, 3... Low temperature separator, 4... CO rectification column, 5... Expansion turbine, 6... Co compressor, 7...Pressure indicating controller, 8...Remote controller. 11...Pressure control valve, 13...Temperature controller, 10,12°14...Valve, 15-35.
...Conduit agent Patent attorney / JN Masaru Kawa
Man-1￥l Figure

Claims (1)

[Claims] 1. In order to rectify and recover carbon monoxide from a raw material gas whose main component is carbon monoxide containing impurities such as hydrogen, nitrogen and methane, the raw material gas is cooled and liquefied to a predetermined temperature. In gas separation equipment, a low-temperature separator consists of a heat exchanger that cools the device to a temperature of A gas separation device characterized in that a temperature controller is provided at the expansion turbine, and the temperature controller is connected to a pressure control valve provided at the inlet of the expansion turbine. 2. A gas separation device according to claim 1, characterized in that a temperature controller is provided in the raw material gas line from the heat exchanger to the low-temperature separator, or in the hydrogen gas line from the low-temperature separator.