JPH065149B2 - How to operate the absorber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a technology for exhausting steam in a vacuum generated under vacuum to recover the heat contained in the steam, and particularly to a boiling point as an absorption liquid in recovering heat from an evaporator. The present invention relates to a method for absorbing and removing water vapor by using an absorber using an aqueous solution having a high rise, a method for recovering heat from low-temperature water vapor by a high-temperature absorbing solution used for absorption and removal, and an apparatus used therefor.

Prior Art In order to cool water or water vapor, it is conducted into a cooling can and flash vaporized under high vacuum. For that purpose, a vacuum generator is connected to the cooling can, but in view of its function, the steam generated in the cooling can must be removed and discharged. Conventionally, this removal uses a condenser to condense water for drainage by using a refrigerant or installing a steam booster.

Also, when low-temperature steam is generated by steam from the final-stage evaporator of a multi-effect evaporator or flash can of a mechanical compression evaporator, or overhead vapor of a distillation column, etc. A heat pump circuit serving as a heat source is assembled, and heat recovery is performed by a compression heat pump, a second-class absorption heat pump, or the like, or it is cooled in the same manner and eliminated as a condensate.

For the treatment of water vapor as described above, low-temperature water vapor is introduced into an absorber and absorbed by a high-concentration absorption liquid, and the absorption liquid contains 98% by weight of sulfuric acid or
Absorb and remove water vapor by using a wt% caustic soda, etc. to absorb it in a high temperature absorbing solution under low temperature and vacuum, and further increasing the temperature of the absorbing solution by the heat of condensation and dilution heat generated at that time. Can recover heat.

The applicant of the present invention has worked on the above-described cooling device, evaporation device, distillation column, and other improved techniques, and has previously filed Japanese Patent Application No. 60-447.
No. 14, Invention title “Vacuum exhaust method and apparatus using it”, Japanese Patent Application No. 60-129136, Invention title “High vacuum evaporator”, Japanese Patent Application No. 60-140580, Invention title “High vacuum” The related inventions as proposed in "Evaporation device and absorber used therefor" and Japanese Patent Application No. 60-147649, entitled "Heat recovery device such as evaporation device" have been completed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In any of the above-described methods for removing water vapor, a method for recovering heat from various devices associated therewith, or an apparatus for carrying out the method, the absorbent is circulated and supplied And
The circulation line was provided with an absorption liquid supply port and an absorption liquid discharge port, and was additionally provided with a supply source such as a stock solution tank for the absorbent.

An absorber having such an absorption liquid circulation line is operated by setting the concentration of the absorption liquid, but the diluted absorption liquid concentration is 35%.
In the case of more than 40% by weight, especially when using 40% by weight of caustic soda as the stock solution of the absorbent, the difference in the concentration with the dilution concentration is small, resulting in an extremely large consumption of the stock solution of the absorbent. was there. Furthermore, when operating in a high vacuum or when recovering heat at a high temperature, it is necessary to increase the concentration of the circulating absorbent or lower the temperature of the absorbent so that re-evaporation of absorbed water vapor does not occur. With caustic soda, there is a problem that design becomes impossible and operating conditions become narrow. Furthermore, high concentration caustic soda is 48%
In this case, since the freezing point in the stock solution tank was about 15 ° C., a heating means was required to prevent freezing in the winter.

Means for Solving the Problems The present invention is intended for setting operating conditions of an absorber when using an absorber having a circulation line of an absorbing liquid that absorbs vapor for discharging and removing steam and recovering heat. The purpose is to improve the absorbent supply method and the equipment therefor, and dissolve or adjust solid or high-concentration caustic soda in the high-concentration absorbent stock solution inlet connected to the absorption liquid circulation line provided in the absorber. A solid caustic soda or the like is put into this dissolution tank, and a part of the diluent extracted from the absorption liquid circulation line is injected into the same dissolution tank through a drain port and used to dissolve the caustic soda for 40 to 50 minutes. The gist of this is to adjust the amount to the weight% and then to quantitatively inject it into the circulation line from the supply port. In general, use a small amount of solid caustic soda to improve the effectiveness of the absorbent in the absorber. There is.

Action The present invention will be described in detail based on the preferred embodiments shown in the drawings.

In the drawing, 10 is an absorber, and a circulation line 13 for absorbing liquid is provided between a bottom part 11 and an upper part 12 of the absorber, and the absorbing liquid is circulated by a circulation pump 14, and a spray pipe 15 in the absorber 10 is provided. Is supplied from inside. The high-concentration absorbent stock solution is supplied from the supply port 16 to the line 13 and appropriately extracted from the drainage port 17, but during this time, the steam 20 introduced into the absorber 10 is absorbed to generate heat of condensation and heat of dilution. Further, heat of dilution of the concentrated stock solution added from the supply port 16 is further applied to the heat equipment 30 such as a heat exchanger provided in the circulation line 13 so as to recover the heat and simultaneously cool the absorbing solution.

An absorbent dissolving tank 40 is connected to the absorbent supply port 16 and the drainage port 17 of the circulation line 13 via pumps 18 and 19, respectively. This dissolution tank has a stirrer 41, a predetermined amount of high-concentration absorbent stock solution 42, and solid caustic soda 43 that is continuously or intermittently charged therein.
Dissolve. In addition, a part of the diluting liquid of the absorbing liquid is introduced from the pump 19 into the tank through the branch pipe 44 and used for dissolving the caustic soda. The absorption liquid whose concentration is adjusted here passes through the pump 18 and the supply line 16 to the circulation line 1.
Add to 3 and circulate. That is, the solid caustic soda 43 is quantitatively charged, the high-concentration absorbent stock solution 42 is maintained at a constant concentration, and the circulation line 1 is quantitatively supplied from the pump 18 and the supply port 16.
Send to 3. This absorbent stock solution is diluted by the circulating fluid,
The temperature of the high-temperature absorbing liquid is further raised, and the heating device 30 performs a heating action, and then reaches the water absorber 10, where the water vapor 20 drawn in a high vacuum is absorbed, and the temperature is raised by its condensation heat and dilution heat.

The circulating liquid is extracted from the drainage port 17 in a required discharge amount and a required amount for dilution according to the injection of the high-concentration stock solution of the absorbent from the supply port 16, and a part thereof is quantitatively dissolved in the dissolution tank 40. Four
4, and the rest is extracted as a diluted withdrawal liquid 45 having other uses.

Since the solid caustic soda 43 is dissolved in the dissolution tank 40 by using the diluting liquid extracted from the circulation line, a small amount of solid caustic soda can be supplied to adjust the concentration, and the set concentration can be easily obtained. The caustic soda is not limited to solid one, and uniform high-concentration caustic soda can be used. Furthermore, since the high-concentration absorbent stock solution in the dissolution tank becomes high temperature due to the heat of dissolution, no heating means for freeze prevention is required in winter, and this heat is used together with the absorption solution for heat recovery in the heat device 30. is made of.

Example In the example shown in FIG. 2, the dissolution tank 40 was charged with 97% by weight of solid caustic soda at a rate of 337 Kg / hr, and 1830 Kg / hr of the 4497 Kg / hr diluted solution extracted from the circulation line. A dilute solution 44 of 2 gives 2167 Kg / hr of 48% by weight of caustic soda. In the circulation line 13, the concentration of the circulating absorption liquid diluted to 39% in the absorber 10 is restored to 39.5% by the injection (16) of the undiluted solution, and the circulating absorption liquid further heated by the heat of dilution of the undiluted solution is After being heated by the heat exchanger 30, it is sent to the absorber 10. The inside of the absorber 10 is controlled by the vacuum generator 50.
It is kept at a vacuum of 6 Torr, which causes 20
Is absorbed by absorbing 500 Kg / hr. The absorption liquid is diluted to 39% by weight.

The circulating absorbent is circulated according to the heating design at about 100 ton / hr, of which 4497 Kg / hr is extracted from the outlet 18, of which 2667 Kg / hr is the caustic soda aqueous solution as a diluted extract, and the remaining portion is 1830 Kg / hr. hr
Was sent to the dissolution tank 40 to dissolve the caustic soda 43 supplied as a solid, and the above cycle of the circulating absorbent was completed, and the removal of the steam 20 and the heat recovery by the temperature rise were achieved.

EFFECTS OF THE INVENTION The present invention is an absorber effectively used in the removal of steam and the recovery of heat accompanying it, and since solid caustic soda is used to adjust the circulating absorbent, a concentrated stock solution of the absorbent is obtained. (1) A large concentration difference can be obtained with respect to the concentration of the diluted absorbent, and the amount of solid caustic soda used is significantly smaller than that of 48 wt% caustic soda. For example, when the concentration of diluted caustic soda is 47% by weight, absorbed vapor 100 Kg / hr
The required amount of the 48% absorbent stock solution per unit is 4700 kg / hr, and 94 kg / hr if solid caustic soda is used here.
Will be about 1/50.

(2) Since the concentration of circulating absorbent can be set high, high vacuum,
Wide operating range at high temperature. That is, the degree of vacuum can be increased in a device requiring a low temperature and high vacuum, and the device can be recovered in a higher temperature range in a device for recovering heat.

(3) The heating means for preventing the freezing of the high-concentration caustic soda supply liquid tank becomes unnecessary.

(4) Overall, the operating conditions of the absorber are stable, and the advantages of steam removal and heat recovery incorporating the absorber can be improved from the prior art.

[Brief description of drawings]

The drawings are explanatory views of a concrete apparatus according to the present invention, FIG. 1 is a schematic view of the apparatus shown in a flow chart, and FIG. 2 is an explanatory view of an operation example of the apparatus of FIG. 10 Absorber, 13 Circulation line 15 Dispersion pipe, 16 Supply port 17 Discharge port, 18, 19 Pump 20 Steam, 30 Heat equipment (heat exchanger) 40 Dissolution tank, 41 Stirrer 42 High concentration absorbent stock solution, 43 Solid Caustic soda 44 Diluted solution, 45 Diluted solution 50 Vacuum generator

Claims (1)

[Claims] 1. An absorption liquid circulation line having a supply port for supplying a stock solution of an absorbent using caustic soda and a drainage port for an absorption dilution liquid is provided in an absorber which holds a vacuum and sucks water vapor, In the operating method of the absorber, which absorbs and removes vapor by the absorbing solution and recovers heat from the heated absorbing solution, the solid caustic soda is dissolved by a part of the 35% by weight or more caustic soda diluent extracted from the circulation line. A method for operating an absorber, which comprises adjusting the concentration of an undiluted solution of an absorbent and supplying the undiluted solution to the absorbent through a supply port.