JPH0789007B2 - Carbon monoxide separation and purification equipment - Google Patents

Description

TECHNICAL FIELD The present invention separates carbon monoxide from a carbon monoxide-producing gas produced by oxidizing propane, butane, or the like, a byproduct gas of a steel mill, or the like. The present invention relates to a carbon monoxide separation / purification device.

[Conventional technology]

Carbon monoxide (CO) is used as a raw material for synthetic chemistry because of its high reactivity, and in recent years, it has been considered to be the most important carbon source in C ₁ chemistry. The above CO is
It is contained in a large amount in the by-product gas of steelworks and other factories, and conventionally, at most, thermal energy is recovered as fuel. However, due to the increasing demand for CO in recent years, a device for separating and recovering CO from the above factory by-product gas has been developed. Further, in recent years, in view of the importance of CO as described above, an apparatus for separating and recovering CO from a CO source gas produced by oxidizing propane, butane, etc. has been proposed. An adsorbent such as zeolite is mainly used for these devices, and CO adsorbent concentrates and collects CO and COSORB (COSOR) that selectively absorbs CO.
B) Two types of equipment are used, one that uses liquid. However, the adsorption-separation device (based on the PSA method) that uses the above-mentioned adsorbent requires a large number of valves in the device itself, and at the same time, it is necessary to switch the adsorbent by valve operation and recycle it. Is complicated, and complicated valve operation is required. In addition, since the recovery rate of CO from the raw material gas is low, it is necessary to mix the waste gas with the raw material gas again to separate and collect CO, which results in high running costs and high product CO. ing. In addition, there is a problem that only high purity CO can be obtained, and high purity products cannot be obtained.

[Problems to be solved by the invention]

When the Cossorb method is carried out, it has an advantage that a large number of valves as in the PSA device described above are not required, and for example, separation and recovery of CO is realized for steelworks by-product gas such as converter gas. The composition of the converter gas is _{CO; 68~72vol%, CO 2:} 1
3 to 17vol%, N ₂ ; 11 to 16vol%, H ₂ ; 0.8 to 1.3vol%, O ₂ ; 0.1v
ol% or less, other than that, ammonia, hydrogen sulfide,
It contains trace components such as sulfur dioxide, dust and about 7% water. FIG. 3 shows an example of a co-sorbing device for such a gas. In the figure, 40 is a raw material gas composed of a converter gas, and 41 is a compressor, which compresses the carbon dioxide gas to raise the pressure. In this compressor 41, dust is collected in the oil of the compressor 41 and removed by a filter installed in an oil circulation system for cooling this oil. A brine cooler 42 preliminarily dehumidifies the pressurized raw material gas.
43 is an adsorption column filled with activated carbon that adsorbs and removes sulfur and ammonia in the raw material gas. Reference numeral 44 is a set of two adsorption columns filled with synthetic zeolite for adsorbing and removing water and carbon dioxide. The pair of suction cylinders 44 are alternately switched and used. Reference numeral 45 denotes an absorption tower, in which the raw material gas from which the above impurities have been removed and dehumidified is brought into countercurrent contact with the cosorb liquid flowing down from the upper part of the tower so that CO in the raw material gas is selectively absorbed by the cosorb liquid. . The above cosoave liquid is toluene and CuAl.
It is a solution of Cl ₄ and selectively absorbs CO at low temperature and emits CO at high temperature by the following reaction.

47 is a heat exchanger, which selectively absorbs CO in the absorption tower 45
The cossorb liquid delivered from the bottom of the is heated by exchanging heat with the liquid delivered from the bottom of the stripping tower 46. 46 is a stripping tower, in which the CO-absorbing COSORB liquid is flown down from the top of the tower, and brought into contact with the toluene vapor generated by heating the reboiler 49,
CO Absorbs CO in COSORB solution. Here, the COSORB liquid that has diffused CO is cooled and regenerated from the bottom of the diffusion tower 46 via the heat exchanger and the cooling tower 48, and is returned to the top of the absorption tower 45. Waste gas is sent from the upper part of the absorption tower 45, cooled to −10 ° C. by the brine cooler 42 ′ to recover toluene, and sent to a piping system for blast furnace gas or the like. Then, the product CO (gas) is taken out from the upper part of the stripping tower 46. In this case, a small amount of CO ₂ , N ₂ , H ₂ , and O ₂ is dissolved in the cossorb liquid, so that the product CO obtained from the stripping tower 46 contains these. 50 is a water cooling tower, which cools the above product CO and recovers toluene. 51 is a compressor, which boosts the pressure of the product CO. 52 is a brine cooler which cools the above product CO to -10 ° C and recovers toluene. Reference numeral 53 is a product CO storage tank, which appropriately sends the product CO. However, in the above-mentioned apparatus, trace amounts of impurities are inevitably mixed in the product CO, so that it is practically impossible to recover ultra-high purity carbon monoxide, and only about 99.5% is obtained. In addition, this device also has a drawback that the recovery rate of product CO is low.

The present invention has been made in view of such circumstances, and an object thereof is to provide a carbon monoxide separation / purification device capable of recovering ultrahigh-purity carbon monoxide at a high recovery rate.

[Means for solving problems]

In order to achieve the above object, the apparatus for separating and purifying carbon monoxide of the present invention is a compression unit for compressing a raw material gas containing carbon monoxide, a removing unit for removing carbon dioxide gas and water in the raw material gas, A heat exchange means for cooling the raw material gas, a hydrocarbon-based impure gas liquefaction remover for cooling and condensing the hydrocarbon-based impure gas to liquefy, and a raw material gas passed through the heat exchange means built in the condenser. A raw material gas supply path leading to the condenser of the cooler, a rectification tower that liquefies carbon monoxide in the raw material gas due to the difference in boiling points and stores it inside to separate and discharge the impure gas, and liquid nitrogen from outside the device. Liquid nitrogen storage means for receiving and storing the liquid nitrogen, a first introduction path for guiding the liquid nitrogen in the liquid nitrogen storage means to the rectification column as a cold source for liquefying carbon monoxide, and the liquid nitrogen storage means. Liquid nitrogen in the A second introduction path leading to the hydrocarbon-based impure gas liquefaction remover as a cold source for gas liquefaction and an extraction path for taking out the stored liquefied carbon monoxide in the rectification tower as a product carbon monoxide as it is or in a gaseous state. Take the configuration to prepare.

That is, this apparatus is a cryogenic liquefaction separation method, and the raw material gas obtained by the compression means, the removal means, and the heat exchange means is introduced into a hydrocarbon-based impure gas liquefaction remover to liquefy the hydrocarbon-based impure gas. At the same time as removing it, the raw material gas is cooled to an ultra low temperature,
This is led to a rectification column, and further cooled by the cold heat of liquid nitrogen supplied from the liquid nitrogen storage means to liquefy CO in the raw material gas and remove the impure gas as a gas. At the same time as discharging from the rectification tower, liquefied CO
In order to take out as it is or vaporized,
It becomes possible to recover ultrahigh-purity carbon monoxide. That is, this device utilizes CO absorption and desorption by heating and cooling the cosorb liquid as in the above cosorb device,
Since it does not utilize the absorption by the adsorbent unlike the PSA device, it may dissolve trace amounts of impure gas such as CO ₂ and N ₂ in the cossorb liquid, or may contain impurities such as impure gas due to poor adsorption of the adsorbent. Therefore, the phenomenon of impairing the purity of the product carbon monoxide due to these impure dissolved components does not occur.

Next, a detailed description will be given based on an embodiment of the present invention.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, 1 is a raw material gas compressor, 2 is a drain separator, 3 is a Freon cooler, and 4 is a set of two adsorption tubes. The adsorption cylinder 4
Is filled with synthetic zeolite or activated carbon or a mixture of both, and adsorbs and removes H ₂ O, CO _{2 and the} like in the raw material gas compressed by the raw material gas compressor 1. 5 is
This is a raw material gas supply pipe for sending a raw material gas from which H ₂ O, CO _2, etc. have been adsorbed and removed. 6 is a heat exchanger,
The compressed raw material gas from which H ₂ O, CO _2, etc. have been adsorbed and removed is fed. Reference numeral 7 denotes a hydrocarbon-based impure gas liquefaction remover that liquefies and removes a hydrocarbon-based impure gas such as CH ₄ by cooling and condensing in the built-in condenser 8. Reference numeral 9 is a pipe for feeding the compressed raw material gas cooled by the heat exchanger 6 into the condenser 8 of the hydrocarbon-based impure gas liquefaction remover 7. 10 is the condenser 8
The hydrocarbon-impurity gas that has been condensed and liquefied by cooling in the condenser 8 is discarded by a discharge pipe that extends downward from. Reference numeral 25 is a heat exchanger provided in the middle portion. Above heat exchanger 25
Is a part of the compressed raw material gas sent by the branch pipe 26 branched from the pipe 9 is cooled by the cold heat of the fluid (liquefied hydrocarbon-based impure gas) passing through the discharge pipe 10, and is returned by the return pipe 27. It returns to the pipe 9 as shown by the arrow. Reference numeral 11 denotes a rectification column, which is composed of a condenser section 12 having a built-in condenser 28 and a medium pressure column section 13, and a large number of rectification shelves 14 are arranged in the medium pressure column section 13. . A low-temperature raw material gas feed pipe 29 extending from the condenser 8 of the hydrocarbon-based impure gas liquefaction remover 7 is opened in the tower portion 13, and the hydrocarbon-based impure gas is liquefied and removed and cooled to an ultralow temperature. The raw material gas is being sent in. In this tower section 13, a part of CO in the raw material gas is liquefied and flows downward, and H ₂ , N ₂
The remaining impure gas such as CO and the rest of CO rise in the gaseous state above the tower section 13. 15 is a condenser in the upper part of the tower section 13 and in the partial condenser section 12
28 is the first reflux liquid pipe that connects with
The mixed gas, which has risen upwards, is fed into the condenser 28. A shielding plate 15a forms a flow path for guiding the mixed gas to the first reflux liquid pipe 15, and the impure gas (H ₂ ,
N ₂ ) is mixed with the mixed gas to prevent impure gas from staying at the top of the column. In the condenser 28, CO is liquefied due to the difference in boiling points, and N ₂ , H _{2 and the} like are removed in a gaseous state through a waste gas pipe 30 extending upward from the condenser 28. Reference numeral 16 denotes a second reflux liquid pipe extending from the lower portion of the condenser 28 into the upper portion of the tower portion 13, and the liquefied CO accumulated at the bottom portion of the condenser 28 flows down as a reflux liquid into a tray 17 in the tower portion 13. It is getting to let you. Liquefaction that has flowed down into this pan 17
The CO overflows and flows downward in the tower section 13, comes into countercurrent contact with the raw material gas fed into the tower section 13 through the low temperature raw material gas feed pipe 29, and the heat of vaporization causes the raw material gas to flow as described above. CO in gas
It is designed to liquefy gas. Reference numeral 18 denotes a liquid nitrogen storage tank which receives supply of liquid nitrogen from the outside of the apparatus and stores the liquid nitrogen, and the liquid nitrogen in the inside is passed through the first introduction path pipe 32 into the dephlegmator section 12 of the rectification column 11. It is fed and used as a cold source for the condenser 28 in the dephlegmator section 12. Further, the liquid nitrogen in the inside is sent into the hydrocarbon-based impure gas liquefaction remover 7 through the second introduction path pipe 33, and the condenser 8 in the remover 7 is introduced.
As a cold source. Reference numeral 31 denotes a delivery pipe that finishes the action as cold in the dephlegmator section 12 of the rectification tower 11 and delivers vaporized liquid nitrogen, which is in communication with the N ₂ gas extraction pipe 32a, and vaporized liquid nitrogen. Is heat-exchanged via the heat exchanger 6 and then sent out from the N ₂ gas extraction pipe 32a to be used. Reference numeral 19 is a take-out pipe for taking out liquefied CO accumulated in the bottom of the tower section 13 of the rectification tower 11 as product CO. 36 is a storage tank for the product CO, and the product CO is appropriately extracted from this tank 36. The take-out pipe 19 is provided with a control valve 20. A liquid level controller 21 controls the control valve 20 according to the liquid level so that the liquid level of the stored liquefied CO at the bottom of the rectification column section 13 is maintained at a constant level. Further, the control valve 34 provided in the first introduction pipe 32 is also controlled by the liquid level controller 22 so that the liquid level of the liquid nitrogen in the condenser 12 of the rectification column 11 is kept at a constant level. It's getting controlled.
Further, the control valve 35 provided in the second introduction path pipe 33 is also a gas temperature controller provided in the low temperature raw material gas inlet pipe 29.
The temperature of the raw material gas in the low temperature raw material gas supply pipe 29 is controlled to be constant by 35a. The heat exchanger 6, the hydrocarbon-based impure gas liquefaction remover 7 and the rectification column 11 are housed in a vacuum heat insulation container 36a as shown by the one-dot chain line in the figure.

This device is, for example, CO: 69.93vol%, H ₂ ; 30vol%, CH ₄ :
_{0.03vol%, CO 2; 0.03vol%} , N 2; the 0.01 vol% of the composition, CO feed gas as follows to produce a product CO as target (propane, prepared by the oxidation of butane). That is, the raw material gas compressor 1 compresses the raw material gas, the drain separator 2 removes the water content in the compressed raw material gas, and the CFC cooler 3 further cools the raw material gas. Adsorbs and removes H ₂ O and CO ₂ in gas. Then, the raw material gas from which H ₂ O and CO ₂ have been adsorbed and removed is passed through the rectification column 11
Is sent to the heat exchanger 6 which is being cooled by the nitrogen gas and waste gas from the tank, and is cooled in that state, and then is sent into the hydrocarbon-based impure gas liquefaction remover 7, where CH
Liquefaction of hydrocarbon impure gas such as ₄ and then exhaust pipe 1
It is emitted as a room temperature vaporized gas from 0. At this time, the cold heat is recovered by the heat exchanger 25 provided in the discharge pipe 10. Then, the hydrocarbon impure gas is liquefied and removed,
The raw material gas cooled to an ultra-low temperature is fed into the tower portion 13 of the rectification tower 11 and countercurrently brought into contact with the overflow liquefied CO from the tray 17 to liquefy the CO in the raw material gas and the tower portion. Store as liquefied CO at the bottom of 13. At this time, the H ₂ and N ₂ gases in the raw material gas are
Ascend 3 upwards. Further, a part of CO in the raw material gas is not liquefied but rises as it is along with the H ₂ and N ₂ gases as it is. The mixed gas of the ascending H ₂ , N ₂ and CO is fed from the first reflux liquid pipe 15 to the condenser 28 of the rectification column 11, where:
Only the CO gas is liquefied due to the difference in boiling points, and as the reflux liquid, the column portion 13 in the rectification column 11 is passed through the second reflux liquid pipe 16.
Return to the saucer 17 of. On the other hand, the H ₂ and N ₂ gases are taken out from the upper part of the condenser 28 by the waste gas pipe 30, and the heat exchanger 6
It exchanges heat with the source gas inside and is released into the atmosphere. And
The liquefied CO collected at the bottom of the tower section 13 in the rectification column 11 is taken out as a liquefied product from the product liquefied CO take-out pipe 19,
It is temporarily stored in the storage tank 36 and used as appropriate.

As described above, in this apparatus, the raw material gas from which the impurities have been removed by the adsorption tower 4 and the hydrocarbon-based impure gas liquefaction remover 7 is subjected to deep liquefaction separation in the rectification tower 11 to produce liquefied CO. The liquefied CO product obtained has a very high purity. Moreover, even if the demand amount of the product liquefied CO fluctuates, the raw gas temperature control provided in the liquid level controller 22 and the hydrocarbon-based impure gas liquefaction remover 7 in the dephlegmator section 12 of the rectification tower 11 is controlled. With the control action of the total 35a, the amount of liquid nitrogen supplied from the liquid nitrogen storage tank 18 to the dephlegmator section 12 of the rectification column 11 and the hydrocarbon-based impure gas liquefaction remover 7 is automatically controlled. It Therefore, it is possible to automatically and promptly respond to the fluctuation of the demand amount, and at the same time, there is no variation in purity.
In particular, this device constantly guides a part of the raw material gas in the rectification tower 11 into the condenser 28 of the dephlegmator section 12 in the rectification tower 11 and liquefies it. After a predetermined amount has accumulated, the liquefied CO that is generated thereafter will always return to the inside of the tower section 13 of the rectification tower 11 as a reflux liquid. Therefore, the condenser
Variation in product purity due to intermittent supply of reflux liquid from 28 However, the product liquefied CO of stable purity can always be supplied.

FIG. 2 shows another embodiment of the present invention. This apparatus guides the raw material gas that has passed through the hydrocarbon-based impure gas liquefaction remover 7 into the low temperature liquefied gas feed pipe extension 25a that passes through the bottom storage liquefied CO of the rectification column section 13 to produce liquefied CO. It is heated and vaporized, and the vaporized CO is taken out as the product CO gas from the extraction pipe 37, and the liquefied CO generated in the condenser 28 is guided into the liquefied CO reservoir 38 so that it can be taken out as the product liquefied CO from the pipe 39. I'm running. Reference numeral 22a is a liquid level gauge, which controls the opening and closing of the valve 39a by the liquid level of the liquefied CO reservoir 38 to keep the liquid level constant. The other parts are substantially the same as the device of FIG.

This device has an effect that both liquefied CO and gaseous CO can be supplied as product CO.

In addition, although the above-mentioned embodiment shows the liquid removal and both the liquid and the gas extraction, it is also possible to perform the gas extraction in which only the CO gas in the tower section 13 is taken out as the product gas.

〔The invention's effect〕

Since the carbon monoxide separation / purification device of the present invention is configured as follows, it is possible to efficiently produce ultra-high purity carbon monoxide. Moreover, since this device uses liquid nitrogen supplied to the liquid nitrogen storage means from outside the device as a cold source for the rectification column or the like, it does not require a rotating device such as an expansion turbine, and therefore, the rotating device This eliminates the need for troublesome operations such as operation and maintenance, and also enables downsizing of the entire device.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of another embodiment, and FIG. 3 is a block diagram of a conventional example. 1 ... Raw material gas compressor, 4 ... Adsorption cylinder, 6 ... Heat exchanger, 7 ... Hydrocarbon-based impure gas liquefaction remover

Claims (1)

[Claims] 1. A compression means for compressing a raw material gas containing carbon monoxide, a removing means for removing carbon dioxide gas and moisture in the raw material gas, a heat exchange means for cooling the raw material gas, and a carbonization method. A hydrocarbon-based impure gas liquefaction remover for cooling and condensing the hydrogen-based impure gas to liquefy it, a raw material gas supply path for guiding the raw material gas through the heat exchange means into the rectification column, and a raw material gas due to a difference in boiling point A rectification column that liquefies carbon monoxide in the liquid and stores it inside to separate and discharge the impure gas, liquid nitrogen storage means that receives supply of liquid nitrogen from the outside of the device and stores it, and inside this liquid nitrogen storage means Of the liquid nitrogen in the liquid nitrogen storage means as a cold source for liquefying carbon monoxide and the liquid nitrogen in the liquid nitrogen storage means as a cold source for liquefying hydrocarbon impure gas. Second introduction leading to gas liquefaction remover When carbon monoxide separation and purification apparatus characterized by comprising a takeout path taken out as product carbon monoxide as or gaseous state reservoir liquefied carbon monoxide in the rectification column.