JPH0711383B2 - Pretreatment method for air separation device and device thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pretreatment method for an air separation device and the device therefor, and in particular, cooling of raw material air introduced into the air separation device is performed by rinsing and cooling with a cold water tower. The present invention relates to a pretreatment method for an air separation device and a device for performing the purification in an adsorption tower, which are performed in a tower.

[Conventional technology]

An air separation device that collects oxygen, nitrogen, etc. in the air as a product is provided with a pretreatment device for performing compression, pre-cooling, purification, etc. of raw material air.

Among these, as a pre-cooling facility for the raw material air, a combination of a water washing cooling tower and a cold water tower is known. This water washing cooling tower cools the raw material air by introducing the raw material air compressed by the air compressor and having a high temperature from the lower side and directly introducing the cooling water from the upper side to heat-exchange the raw material air. By removing sulfur oxides (SOx), nitrogen oxides (NOx), etc. therein, this cooling water is discharged from the lower part of the water washing cooling tower after cooling the raw material air and sent to the cold water tower.

The cold water tower is for cooling the cooling water used in the water washing cooling tower, and while introducing the cooling water heated upward by directly exchanging heat with the raw air in the water washing cooling tower to the upper side of the air separation device Cooling water is cooled by introducing low-temperature exhaust gas discharged from the main body (cold box) and directly performing heat exchange in the same manner.

On the other hand, an adsorber filled with an adsorbent such as alumina gel or molecular sieves has been widely used for purification for removing water, carbon dioxide gas and the like in the raw material air. In this adsorber, a plurality of groups are arranged in parallel, and adsorption and regeneration are alternately repeated, and the exhaust gas is used during regeneration.

[Problems to be solved by the invention]

When the adsorber is used for refining the raw material air as described above, the lower the inlet air temperature of the adsorber, the better the adsorption efficiency. Therefore, it is better to cool as much as possible before introducing the adsorber. However, since the exhaust gas is preferentially used to regenerate the adsorbent, the amount of exhaust gas required to cool the cooling water in the cold water tower cannot be secured, and a freon refrigeration device, etc. is installed separately to feed air or cool the raw material air. Water cooling had to be done.

Therefore, the present invention is a pretreatment device for an air separation device using an adsorber for refining raw material air, in which an exhaust gas used for regeneration of the adsorber can be effectively used for cooling a cold water tower. It is an object to provide a method and an apparatus thereof.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention firstly provides, as a first invention, a pretreatment of an air separation device including an adsorber for purifying raw material air and a cold water tower for cooling cooling water for cooling raw material air. In the method, the enthalpy i of the regenerated emission gas regenerated by regenerating the adsorber (where enthalpy i is the following equation i = 0.24t + H (0.45t + 595) i: enthalpy (Kcal / Kg dry air) t: gas Temperature (℃) H: From the position where the humidity (Kg-water vapor / Kg-dry air) and the enthalpy i of the ascending gas for cooling of the cooling water tower have the same or similar values. A second aspect of the present invention is a pretreatment device for an air separation device, wherein a regeneration discharge gas is introduced into a cold water tower to cool the cooling water. It is possible to regenerate the adsorber by providing a reproducible gas inlet. The regeneration gas introduction part is moved to a position where the enthalpy i of the derived regeneration emission gas and the enthalpy i of the ascending gas for cooling of the cold water tower have the same value or a close value, and the regeneration emission gas is cooled from the regeneration gas introduction part to the cold water. The cooling water is introduced into the tower to cool the cooling water, and the third invention is a pretreatment device for an air separation device, in which a regeneration gas introduction pipe equipped with a valve is vertically provided on a side wall of the cold water tower. Enthalpy i of the regenerated and discharged gas, which is provided by regenerating the adsorber, and enthalpy i of the ascending gas for cooling the chilled water tower
Opening only the valve of the regeneration gas introduction pipe provided at a position where and have the same value or close values, and introducing the regeneration emission gas from the regeneration gas introduction pipe into the cold water tower to cool the cooling water. Is characterized by.

[Action]

Therefore, the cooling water used for the washing and cooling tower can be efficiently cooled, it is not necessary to provide a freon refrigerating device, etc., and the equipment cost and operating cost of the air separation device can be reduced.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

First, FIG. 1 is a system diagram showing a pretreatment device of an air separation device, and the pretreatment device 1 includes an air compressor (not shown),
It comprises a washing and cooling tower 3 equipped with a cold water tower 2 and a set of adsorbers 5, 5 equipped with a heater 4 for a regenerated gas R.

The raw material air A, which has been compressed by the air compressor and has a high temperature, is supplied from the pipe 6 connected to the lower portion of the washing / cooling tower 3 to the washing / cooling tower 3
And is cooled by the room temperature cooling water L introduced from the middle stage and the cooling water C introduced from the upper stage and is led out from the upper part. The cooled raw material air A is introduced into one of the adsorbers 5 by switching a large number of valves 7 and 7 provided in front of and behind the adsorber 5 to remove carbon dioxide gas and moisture, and then an air separation device from the pipe 8. It is introduced in the cold box of.

The room-temperature cooling water L is led out from the bottom of the water washing cooling tower 3, is sent to a water treatment facility such as a cooling tower, is cooled, and circulates in the middle stage of the water washing cooling tower 3.

Further, the cooling water C is led out from the partition wall 3a in the middle stage of the washing and cooling tower 3 through the pipe 9 and sent to the cold water tower 2, and after being cooled, is pumped by the pump 10 and circulates above the washing and cooling tower 3.

The cold water tower 2 for cooling the cooling water C injects the cooling water C downward from the spray nozzles 11 provided in the upper and lower three stages, and cools the low temperature exhaust gas W from the lower exhaust gas inlet 12. It is introduced as a rising gas U, and on the side wall of the cold water tower 2, a regeneration gas introducing section 13 for regenerating the adsorbent 5a in the adsorber 5 and introducing the regeneration emission gas F derived from the adsorber 5. Is provided.

In the regeneration gas introducing portion 13, a blow-in port 14 for introducing the regeneration emission gas F into the cold water tower 2 is formed so as to be movable up and down, so that the regeneration emission gas F can be introduced at an optimum position according to the state. I have to.

The regeneration emission gas F is released after the exhaust gas W emitted from the cold box is made to flow back to the one adsorber 5 as the regeneration gas R to desorb the carbon dioxide gas and water adsorbed by the adsorbent 5a, Temperature and humidity during the regeneration period, that is, enthalpy i (where enthalpy i is the following equation i = 0.24t + H (0.45t + 595) i: enthalpy (Kcal / Kg dry air) t: gas temperature (° C) H: humidity (Kg-water vapor / Kg-dry air)) changes every moment.

FIG. 2 shows an example of changes in the temperature of the regenerated gas R and the enthalpy i. The raw material air amount is 250000 Nm ³ / h, the pressure is 5.7K.
g / cm ² , adsorber regeneration gas temperature 150 ° C, regeneration time 30 minutes, regeneration gas amount 67760Nm ³ / h, exhaust gas temperature 15 ° C, adsorber switching time 4
It is based on time.

The inlet temperature of the regeneration gas R introduced into the adsorber 5 is about 150 ° C. because it is heated by the heater 4 in the initial stage of regeneration.
The temperature of the exhaust gas W becomes about 15 ° C. by stopping the heating after 30 minutes.

On the other hand, the outlet temperature of the regenerated release gas F, that is, the regenerated gas R discharged from the adsorber 5, gradually rises after the start of regeneration, reaches the maximum temperature after about 70 minutes, and then gradually lowers to approach 15 ° C. To go. At this time, the enthalpy i of the regeneration gas R at the outlet of the adsorber 5 rises sharply due to the temperature increase after the start of regeneration and the increase in water content due to the desorption of the adsorbed component, and as the temperature decreases and the concentration of the desorbed component decreases. Gradually descend.

In order to introduce the regenerated emission gas F whose enthalpy i changes into the cold water tower 2, it is necessary to consider the enthalpy i of the rising gas U for cooling in the cold water tower 2.

For example, if the rising gas U for cooling at the inlet of the cold water tower 2 has an enthalpy i of 3.96 Kcal / Kg, an intermediate portion of 13.25 Kcal / Kg, and an outlet of 22.5 Kcal / Kg, the enthalpy i is 22.5 Kcal / Kg.
Since the cooling water C cannot be cooled even if the above-mentioned regeneration discharge gas F is introduced into the cold water tower 2, it must be discharged and discharged into the atmosphere or the like.

Similarly, even if the regenerated emission gas F is introduced above the middle portion of the cold water tower 2, the cooling effect is small, and the equipment and piping are only complicated. Therefore, the regeneration emission gas F with an enthalpy i of about 15 Kcal / Kg or more is used. It is also preferable to discharge and exhaust.

When the regeneration emission gas F is introduced at a fixed position of the cold water tower 2, for example, at the same height as the inlet of the exhaust gas W at the lower portion of the cooling water tower 2, the enthalpy i of the regeneration emission gas F is substantially equal to the enthalpy i of the exhaust gas W. If it is not the same, the cooling water C cannot be cooled to the specified temperature. For example, mixing exhaust gas W95040Nm ³ / h with an enthalpy i of 3.96Kcal / Kg and regeneration emission gas F67760Nm ³ / h with an enthalpy i of 13.6Kcal / Kg, the enthalpy i of the mixed gas is 7.98Kcal / Kg.
Therefore, the cooling capacity becomes insufficient. Therefore, for example, until the enthalpy i of the regenerated emission gas F becomes 4.0 Kcal / Kg or less, the exhaust gas must be emitted to the outside without being introduced into the cold water tower 2. Gas F
Cannot be used for cooling the cooling water C. (Part q1 in FIG. 3) Therefore, if the regenerated emission gas F is introduced from the middle portion of the cold water tower 2 where the enthalpy i of the rising gas U for cooling is high, the enthalpy i of the regeneration emission gas F is 14.7 Kcal / Kg
It is possible to use the regenerated emission gas F below, that is, after about 1 hour has elapsed from the start of regeneration. The enthalpy i of the mixed gas at this time changes from 13.8 Kcal / Kg to 9.3 Kcal / Kg (Fig. 3, q2 part).

In this way, when a gas with a low enthalpy i is mixed in the middle portion of the cold water tower 2, the enthalpy i of the cooling rising gas U decreases and the ability to cool the cooling water C also increases. Therefore, the dashed line in FIG. As described above, the temperature of the cooling water in the middle portion of the cold water tower 2 can be lowered, but in the lower position, heat exchange is hardly performed until the temperature difference with the rising gas U for cooling reaches the set temperature, and the cold water tower 2 The effect of lowering the temperature of the cooling water C at the outlet is small, and as a result, the temperature distribution in the cold water tower 2 becomes discontinuous, which is not a preferable result in terms of the performance of the cold water tower 2.

Further, generally, mixing gases having different enthalpies i results in a decrease in energy.
The energy for cooling that has cannot be effectively used. Therefore, the cooling water C cannot be sufficiently cooled in the cold water tower 2,
Separately, it is necessary to add a refrigerating device to cool.

Therefore, in order to effectively use the cooling energy of the regenerated and discharged gas F, the cooling rising gas U rising in the chilled water tower 2 and the regenerated and discharged gas F should have the same enthalpy i at the same position. Need to mix. By mixing in such a state, it is possible to minimize the change in the enthalpy i inside the cold water tower 2, and
The cooling energy of the regeneration emission gas F can be used without waste.

That is, the period in which the enthalpy i of the regenerated emission gas F is higher than the enthalpy i of the ascending gas U for cooling of the cold water tower 2 is
Releasing the regeneration discharge gas F from the discharge valve 14 shown in the figure,
When the enthalpy i of the regeneration discharge gas F reaches a value that can be introduced into the cold water tower 2, the regeneration discharge gas F is introduced into the middle or upper portion of the cold water tower 2 at substantially the same position as the enthalpy i of the rising gas U for cooling.

Then, depending on the extent to which the enthalpy i of the regenerated exhaust gas F decreases, the introduction position is gradually set to the lower part of the cold water tower 2. As a result, the enthalpy i of the mixed gas in the cold water tower 2 can be continuously changed, and the cooling energy of the regenerated and discharged gas F can be effectively used without being wasted. Therefore, as shown in FIG. 2, the cooling water C
Can be cooled to a temperature lower than that of the exhaust gas W alone, and the raw material air A
Since the temperature can be lowered, the adsorption efficiency in the adsorber 5 can also be improved.

5 to 8 are enlarged views of the regenerated gas introducing portion shown in FIG. 1, FIG. 5 is a plan view, FIG. 6 is a front view, and FIG. 7 is a gas introducing portion portion. Front view of Fig. 8 is No. 7
FIG. 8 is a sectional view taken along the line VIII-VIII of the figure.

The regeneration gas introduction part 13 is provided so as to cover the opening 2b provided at the side wall 2a of the cold water tower 2, and the introduction part cover 15 is fixedly provided inside the introduction part cover 15 so as to be fixedly provided at the side wall 2a. A guide member 16, a slide plate 17 guided by the guide member 16 to slide up and down, a blow opening 14 provided through the slide plate 17, and a vertical movement of the blow opening 14. Wire
And a motor 19 connected to the slide member 17 via 18. Further, the regenerated gas introduction section 13 is provided so as to face the non-uniform flow of the cooling rising gas U in the cooling tower 2, and the branch pipes 21, 21 are connected to the end of the regenerated gas conduit 20. The regeneration discharge gas F is branched.

The regeneration discharge gas F is introduced from the regeneration gas conduit 20 through the branch pipe 21 into the regeneration gas introduction part 13 and is located at a position corresponding to the enthalpy i of the cooling rising gas U consisting of the exhaust gas W introduced from the exhaust gas introduction port 12. It is introduced into the cold water tower 2 through the adjusted blowing port 14 and mixed with the ascending gas U for cooling.

That is, when the enthalpy i of the regenerated emission gas F is high,
The electric motor 19 is rotated to raise the blow-in port 14, the regeneration emission gas F is introduced to a predetermined position such as the middle portion of the cold water tower 2, and the electric motor 19 is rotated in reverse as the enthalpy i of the regeneration emission gas F decreases. The blowing port 14 is moved downward.

The rotation of the electric motor 19 at this time can be continuously or intermittently performed by a predetermined program, or can be automatically controlled by detecting the temperature or the like of the regeneration discharge gas F in the regeneration gas conduit 20. .

FIG. 9 shows another embodiment for introducing the regeneration discharge gas F to a predetermined position of the chilled water tower according to its enthalpy i. The regeneration gas introduction pipe 2 provided with valves 23a, 23b, 23c, respectively.
4a, 24b, 24c are provided in the vertical direction of the cold water tower 22.
Since the devices other than the cold water tower 22 are the same as those shown in FIG. 1, the same reference numerals are given and the description thereof will be omitted.

The valves 23a, 23b, 23c of the regeneration gas introducing pipes 24a, 24b, 24c are opened / closed according to the enthalpy i of the regeneration emission gas F, and when the enthalpy i of the regeneration emission gas F is high, Only the valve 23a of the provided regeneration gas introduction pipe 24a is opened. Then, as the enthalpy i of the regeneration discharge gas F decreases, the lower valves 23b and 23c are sequentially opened and the upper valve 23 is opened.
a and 23b are closed. As a result, the regenerated emission gas F is
Regeneration gas introduction pipes 24a, 24b, 24 according to the enthalpy i
It is introduced from c to a predetermined position in the vertical direction of the cold water tower 22, and is mixed with the cooling rising gas U to efficiently cool the cooling water C.

Depending on the width of change of the enthalpy i of the regeneration discharge gas F and the size of the cold water tower 22, the regeneration gas introduction pipes 24 are provided at appropriate intervals and opened / closed according to a predetermined program. Alternatively, the opening / closing control is automatically performed according to the temperature of the regeneration discharge gas F in the regeneration gas conduit 20 or the like.

〔The invention's effect〕

As described above, the present invention introduces the regeneration emission gas into the cold water tower from a position where the enthalpy i of the regeneration emission gas and the enthalpy i of the ascending gas for cooling of the cold water tower are the same or close to each other. Since the cooling is performed, the energy of the regenerated gas can be effectively used, and the cooling water can be cooled to a predetermined temperature or lower without adding refrigeration equipment such as a Freon refrigerator. Therefore, the equipment cost and operating cost of the air separation device can be reduced. Further, in the second aspect of the invention, the position of the regenerated emission gas introduced into the cold water tower can be continuously adjusted according to the enthalpy i, so that efficient energy utilization can be achieved. Further, in the third invention, since the pipe provided with the valve is simply provided in the cold water tower, the facility cost is low and the present invention can be easily applied to the existing device.

[Brief description of drawings]

FIG. 1 is a system diagram showing a pretreatment device for an air separation device, and FIG.
The figure is an illustration of changes in the temperature and enthalpy of the regeneration gas,
FIG. 3 is an explanatory diagram of changes in temperature and enthalpy in the cold water tower, and FIG. 4 is an explanatory diagram of changes in vertical position and temperature of the cold water tower,
5 to 8 are enlarged views of the regenerated gas introduction part, FIG. 5 is a plan view of the cold water tower, and FIG. 6 is a front view of the same.
Fig. 7 is a front view of the gas introduction part, and Fig. 8 is VI of Fig. 7.
II-VIII sectional view, FIG. 9 is a system diagram showing a pretreatment device of an air separation device showing an embodiment of another method for introducing the regenerated and discharged gas to a predetermined position of the cold water tower. 1 ... Pretreatment device, 2, 22 ... Cold water tower, 3 ... Washing cooling tower, 5 ... Adsorber, 11 ... Spray nozzle, 12 ... Exhaust gas inlet, 13 ... Regeneration gas inlet, 14 ...... Blowout port, 15 ...
… Introduction cover, 16 …… guide member, 17 …… slide plate, 19 …… motor, 20 …… regeneration gas conduit, 21 …… branch pipe, 23a, 23b, 23c …… valve, 24a, 24b, 24c… Regeneration gas inlet pipe, A ... Raw material air, C ... Cooling water, F ... Regeneration emission gas, L ... Room temperature cooling water, R ... Regeneration gas, U ... Ascending gas for cooling, W ... Exhaust gas

Claims (3)

[Claims] 1. A pretreatment method for an air separation device comprising an adsorber for purifying raw material air and a cold water tower for cooling cooling water for cooling raw material air, wherein regeneration is performed by regenerating the adsorber. The regeneration emission gas is introduced into the cold water tower from a position where the enthalpy (i) of the released gas obtained by the following formula and the enthalpy (i) of the cooling rising gas of the cold water tower have the same value or a close value, A pretreatment method for an air separation device, which comprises cooling the cooling water. i = 0.24t + H (0.45t + 595) i: Enthalpy (Kcal / Kg dry air) t: Gas temperature (℃) H: Humidity (Kg-steam / Kg-dry air) 2. A pretreatment device for an air separation device comprising an adsorber for purifying raw material air and a cold water tower for cooling cooling water for cooling the raw material air, which is vertically movable on a side wall of the cold water tower. A regeneration gas introduction part is provided, and the enthalpy (i) of the regeneration emission gas derived by regenerating the adsorber is the same as the enthalpy (i) of the ascending gas for cooling the cooling water tower. Of the regeneration gas is moved to a position having a value or a close value, the regeneration emission gas is introduced from the regeneration gas introduction part to a cold water tower, and the cooling water is cooled. Pretreatment equipment. i = 0.24t + H (0.45t + 595) i: Enthalpy (Kcal / Kg dry air) t: Gas temperature (℃) H: Humidity (Kg-steam / Kg-dry air) 3. A pretreatment device for an air separation device comprising an adsorber for purifying raw material air and a cold water tower for cooling cooling water for cooling the raw material air, wherein regeneration is provided with a valve on a side wall of the cold water tower. Gas introduction pipes are provided at a plurality of positions in the vertical direction, and the enthalpy (i) of the regenerated emission gas derived by regenerating the adsorber and the enthalpy (i) of the rising gas for cooling the chilled water tower (i) ) Is opened at the same value or a value close to it, only the valve of the regeneration gas introduction pipe is opened, and the regeneration emission gas is introduced from the regeneration gas introduction pipe into the cold water tower to cool the cooling water. A pretreatment device for an air separation device, which is characterized by carrying out. i = 0.24t + H (0.45t + 595) i: Enthalpy (Kcal / Kg dry air) t: Gas temperature (℃) H: Humidity (Kg-steam / Kg-dry air)