CN215876264U - Concentration unit of flake caustic soda production system - Google Patents

Abstract

The utility model discloses a concentration unit of a flake caustic soda production system, which comprises a feeding pipe, a molten salt tank, a molten salt pump, a molten salt furnace, a main concentrator and a flash tank, wherein an outlet of the feeding pipe is communicated with a feeding hole pipeline of the pre-concentrator, and an exhaust port of a separator of the main concentrator is communicated with a jacket inlet pipeline of the pre-concentrator. The advantages are that: the secondary steam that produces through main concentrator sends into in the preconcentrator carries out preconcentration to sodium hydroxide solution, can carry out recycle to the heat of secondary steam on the one hand, and on the other hand can improve the concentration of the sodium hydroxide solution that gets into main concentrator, improves the concentration efficiency of main concentrator, reduces the natural gas consumption reduce cost, and under equal heating temperature, can produce the sodium hydroxide solution of higher concentration, obtains better quality caustic soda flakes. Sugar water can be fed into the system by arranging a sugar liquid storage tank, a preparation tank and the like, so that the problem that the pre-concentrator and the main concentrator are corroded by caustic soda is solved.

Description

Concentration unit of flake caustic soda production system

The technical field is as follows:

the utility model relates to the technical field of caustic soda flake production, in particular to a concentration unit of a caustic soda flake production system.

Background art:

the concentration unit in the flake caustic soda production system is mainly used for heating and concentrating low-concentration NaOH to obtain high-concentration NaOH solution; the concentration unit generally comprises a feeding pipe, a molten salt tank, a molten salt pump, a molten salt furnace, a main concentrator and a flash tank, wherein an inlet of the molten salt pump is communicated with an outlet pipeline of the molten salt tank, an outlet of the molten salt pump is communicated with an inlet of the molten salt furnace, an outlet of the molten salt furnace is communicated with a jacket inlet pipeline of the main concentrator, a jacket outlet of the main concentrator and an inlet pipeline of the molten salt tank are communicated with a discharge hole of a separator at the bottom of the main concentrator and an inlet pipeline of the flash tank; in the concentration process, about 50% of NaOH solution is added into a main concentrator through a feeding pipe, a molten salt pump sends the molten salt in a molten salt tank to a molten salt furnace, the molten salt is heated by using heat generated by natural gas and hydrogen and then sent into a jacket of the main concentrator, the NaOH solution in the main concentrator is concentrated, the molten salt is returned to the molten salt tank for recycling, the NaOH and steam concentrated by the main concentrator are separated by a separator at the bottom of the separator, the NaOH solution discharged by the separator is sent into a flash tank for flash evaporation, and then the NaOH solution is sent into a distributor for distribution to a tablet making machine and a packaging process. In the operation process of the system, the problem of large consumption of natural gas exists; in addition, in the solid caustic soda production, high-temperature concentrated caustic soda has certain corrosivity on nickel equipment, and the corrosion is mainly caused by that chlorate contained in alkali liquor is gradually decomposed at the temperature of more than 250 ℃, nascent oxygen is released to react with nickel materials to generate a nickel oxide layer, the nickel oxide is easily dissolved in the concentrated caustic soda and is taken away by the alkali liquor, and the process is repeatedly carried out in the evaporation of the concentrated caustic soda to cause the corrosion damage of the nickel equipment; the main concentrator adopts a single-tube jacketed heat exchanger, so that equipment is seriously corroded, the failure rate is high, the system is unstable in operation, and the production cost is increased.

The utility model has the following contents:

the utility model aims to provide a concentration unit of a flake caustic soda production system with low energy consumption.

The utility model is implemented by the following technical scheme: the concentration unit of the flake caustic soda production system comprises a feeding pipe, a molten salt tank, a molten salt pump, a molten salt furnace, a main concentrator, a flash tank and a pre-concentrator, wherein an outlet of the feeding pipe is communicated with a feed inlet pipeline of the pre-concentrator, a discharge outlet of a bottom separator of the pre-concentrator is communicated with an inlet pipeline of an intermediate pump, and an outlet of the intermediate pump is communicated with a feed inlet pipeline of the main concentrator; and the exhaust port of the separator of the main concentrator is communicated with the jacket inlet pipeline of the pre-concentrator.

Furthermore, a return pipe is communicated between the outlet of the molten salt furnace and the inlet of the molten salt tank, and a return control valve is mounted on the return pipe.

The device further comprises a sugar liquid storage tank and a preparation tank, wherein an outlet of the sugar liquid storage tank is communicated with an inlet of the weighing tank, an outlet of the weighing tank is communicated with an inlet pipeline of the preparation tank, the top of the preparation tank is communicated with a dilution pipe, and a mass flow controller is arranged on the dilution pipe; the bottom end of the preparation tank is communicated with an inlet pipeline of a feed pump, and an outlet of the feed pump is communicated with a feed inlet pipeline of the pre-concentrator.

The system further comprises a first condenser, a second condenser and a condensed water tank, wherein a jacket exhaust port of the preconcentrator is communicated with an inlet pipeline of the first condenser, a separator exhaust port at the bottom of the preconcentrator is communicated with an inlet pipeline of the second condenser, and a liquid discharge port of the first condenser, a liquid discharge port of the second condenser and a jacket liquid discharge port of the preconcentrator are communicated with an inlet pipeline of the condensed water tank.

Furthermore, an outlet of the condensed water tank is communicated with an inlet pipeline of a condensed water pump, and an outlet of the condensed water pump is communicated with an inlet of the dilution pipe.

The utility model has the advantages that: the secondary steam that produces through main concentrator sends into in the preconcentrator carries out preconcentration to sodium hydroxide solution, can carry out recycle to the heat of secondary steam on the one hand, and on the other hand can improve the concentration of the sodium hydroxide solution that gets into main concentrator, improves the concentration efficiency of main concentrator, reduces the natural gas consumption reduce cost, and under equal heating temperature, can produce the sodium hydroxide solution of higher concentration, obtains better quality caustic soda flakes. Sugar water can be fed into the system by arranging a sugar liquid storage tank, a preparation tank and the like, so that the problem that the pre-concentrator and the main concentrator are corroded by caustic soda is solved.

Description of the drawings:

fig. 1 is a schematic view of the overall structure of the present invention.

The system comprises a feeding pipe 1, a molten salt tank 2, a molten salt pump 3, a molten salt furnace 4, a main concentrator 5, a flash tank 6, a pre-concentrator 7, an intermediate pump 8, a return pipe 9, a return control valve 10, a sugar liquid storage tank 11, a preparation tank 12, a weighing tank 13, a dilution pipe 14, a mass flow controller 15, a feeding pump 16, a first condenser 17, a second condenser 18, a condensed water tank 19 and a condensed water pump 20.

The specific implementation mode is as follows:

as shown in fig. 1, the concentration unit of the flake caustic soda production system comprises a feeding pipe 1, a molten salt tank 2, a molten salt pump 3, a molten salt furnace 4, a main concentrator 5 and a flash tank 6, wherein an outlet of the feeding pipe 1 is communicated with a feeding port pipeline of a pre-concentrator 7, a discharging port of a separator at the bottom of the pre-concentrator 7 is communicated with an inlet pipeline of an intermediate pump 8, an outlet of the intermediate pump 8 is communicated with a feeding port pipeline of the main concentrator 5, an exhaust port of the separator of the main concentrator 5 is communicated with a jacket inlet pipeline of the pre-concentrator 7, and a jacket outlet of the main concentrator 5 is communicated with an inlet pipeline of the molten salt tank 2 and a discharging port of the separator at the bottom of the main concentrator 5 is communicated with an inlet pipeline of the flash tank 6. The sodium hydroxide solution is added into the pre-concentrator 7 through the feeding pipe 1, meanwhile, secondary steam discharged from a separator at the bottom of the main concentrator 5 enters a jacket of the pre-concentrator 7, the sodium hydroxide solution before entering the main concentrator 5 is heated by the secondary steam to realize pre-concentration, the sodium hydroxide solution after pre-concentration enters the main concentrator 5, and then the solution separated from the separator at the bottom of the main concentrator 5 enters the flash tank 6. The secondary steam that produces through main concentrator 5 sends into in preconcentrator 7 carrying out preconcentration to sodium hydroxide solution, can carry out recycle to the heat of secondary steam on the one hand, and on the other hand can improve the concentration of the sodium hydroxide solution that gets into main concentrator 5, improves the concentration efficiency of main concentrator 5, reduces the natural gas consumption reduce cost, and under equal heating temperature, can produce the sodium hydroxide solution of higher concentration, obtains more high-quality caustic soda flakes.

The sodium hydroxide solution in the main concentrator 5 is concentrated by heating molten salt, specifically, an inlet of a molten salt pump 3 is communicated with an outlet pipeline of a molten salt tank 2, an outlet of the molten salt pump 3 is communicated with an inlet of a molten salt furnace 4, an outlet of the molten salt furnace 4 is communicated with a jacket inlet pipeline of the main concentrator 5, the molten salt pump 3 pumps the molten salt in the molten salt tank 2 to the molten salt furnace 4, the temperature is raised by burning natural gas, and the high-temperature molten salt enters the jacket of the main concentrator 5 to heat and concentrate the sodium hydroxide molten salt therein; and then returns to the molten salt tank 2 for recycling. A return pipe 9 is communicated between the outlet of the molten salt furnace 4 and the inlet of the molten salt tank 2, and a return control valve 10 is arranged on the return pipe 9. The molten salt discharged from the molten salt furnace 4 is partially returned to the molten salt tank 2 through the return pipe 9, and the return flow and the amount of the molten salt entering the main concentrator 5 can be adjusted by adjusting the opening degree of the return flow control valve 10, thereby adjusting the concentration temperature of the main concentrator 5.

The jacket exhaust port of the preconcentrator 7 is communicated with the inlet pipeline of the first condenser 17, the separator exhaust port at the bottom of the preconcentrator 7 is communicated with the inlet pipeline of the second condenser 18, and the liquid discharge port of the first condenser 17, the liquid discharge port of the second condenser 18 and the jacket liquid discharge port of the preconcentrator 7 are communicated with the inlet pipeline of the condensate water tank 19. The secondary steam sent by the main concentrator 5 is adopted in the jacket part at the upper part of the pre-concentrator 7, the pressure of the discharged condensed gas is different from that of the condensed gas pumped by the separator at the lower part of the pre-concentrator 7 under negative pressure, and the condensed gas cannot be directly collected into one condenser, so that the gas pumped by the jacket and the separator of the pre-concentrator 7 is cooled and separated by respectively adopting the first condenser 17 and the second condenser 18, and finally, the liquid condensed by the first condenser 17 and the second condenser 18 is sent into the condensed water tank 19 for uniform collection, thereby being convenient for recycling.

The sugar liquid storage tank 11 is used for storing sugar liquid such as cane sugar, an outlet of the sugar liquid storage tank 11 is communicated with an inlet of the weighing tank 13, an outlet of the weighing tank 13 is communicated with an inlet pipeline of the preparation tank 12, and the sugar liquid in the sugar liquid storage tank 11 is metered by the preparation tank 12 and then is added into the preparation tank 12. The top of the preparation tank 12 is communicated with a dilution pipe 14, the outlet of a condensed water tank 19 is communicated with the inlet pipeline of a condensed water pump 20, and the outlet of the condensed water pump 20 is communicated with the inlet of the dilution pipe 14. Part of condensed water collected in the condensed water tank 19 is pumped into the preparation tank 12 through the dilution pipe 14 by the condensed water pump 20, and meanwhile, the dissolution of sugar liquor can be accelerated by utilizing the waste heat of the condensed water, so that high efficiency and energy conservation are realized; a mass flow controller 15 is installed on the dilution pipe 14, and the amount of water added to the preparation tank 12 and thus the concentration of sugar water output from the preparation tank 12 can be controlled by the mass flow controller 15. The bottom end of the preparation tank 12 is communicated with an inlet pipeline of a feed pump 16, an outlet of the feed pump 16 is communicated with a feed inlet pipeline of the pre-concentrator 7, sugar water in the preparation tank 12 can be pumped into the pre-concentrator 7 through the feed pump 16 and then enters the subsequent main concentrator 5, and the pre-concentrator 7 and the main concentrator 5 can be protected from severe corrosion of high-concentration caustic soda by adding the sugar water into a sodium hydroxide solution.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (6)

1. The concentration unit of the flake caustic soda production system comprises a feeding pipe, a molten salt tank, a molten salt pump, a molten salt furnace, a main concentrator and a flash tank, and is characterized by further comprising a preconcentrator, wherein an outlet of the feeding pipe is communicated with a feeding hole pipeline of the preconcentrator, a discharging hole of a bottom separator of the preconcentrator is communicated with an inlet pipeline of an intermediate pump, and an outlet of the intermediate pump is communicated with a feeding hole pipeline of the main concentrator; and the exhaust port of the separator of the main concentrator is communicated with the jacket inlet pipeline of the pre-concentrator.

2. The concentration unit of claim 1, wherein a return pipe is communicated between the outlet of the molten salt furnace and the inlet of the molten salt tank, and a return control valve is mounted on the return pipe.

3. The concentration unit of the flake caustic soda production system according to claim 1 or 2, further comprising a sugar liquid storage tank and a preparation tank, wherein an outlet of the sugar liquid storage tank is communicated with an inlet of a weighing tank, an outlet of the weighing tank is communicated with an inlet pipeline of the preparation tank, a dilution pipe is communicated with the top of the preparation tank, and a mass flow controller is mounted on the dilution pipe; the bottom end of the preparation tank is communicated with an inlet pipeline of a feed pump, and an outlet of the feed pump is communicated with a feed inlet pipeline of the pre-concentrator.

4. The concentration unit of the flake caustic production system according to claim 1 or 2, further comprising a first condenser, a second condenser and a condensed water tank, wherein the jacket gas outlet of the preconcentrator is communicated with the inlet pipeline of the first condenser, the separator gas outlet at the bottom of the preconcentrator is communicated with the inlet pipeline of the second condenser, and the liquid outlet of the first condenser, the liquid outlet of the second condenser and the jacket liquid outlet of the preconcentrator are communicated with the inlet pipeline of the condensed water tank.

5. The concentration unit of flake caustic production system according to claim 3, further comprising a first condenser, a second condenser and a condensed water tank, wherein the jacket vent of the preconcentrator is communicated with the inlet pipeline of the first condenser, the separator vent at the bottom of the preconcentrator is communicated with the inlet pipeline of the second condenser, and the liquid outlet of the first condenser, the liquid outlet of the second condenser and the jacket liquid outlet of the preconcentrator are all communicated with the inlet pipeline of the condensed water tank.

6. The concentration unit of the flake caustic production system of claim 5, wherein an outlet of the condensate tank is in communication with an inlet line of a condensate pump, and an outlet of the condensate pump is in communication with an inlet of the dilution pipe.

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