CN111265909A - Multi-effect evaporation concentration crystallizer and evaporation concentration crystallization method - Google Patents
Multi-effect evaporation concentration crystallizer and evaporation concentration crystallization method Download PDFInfo
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- CN111265909A CN111265909A CN202010219411.5A CN202010219411A CN111265909A CN 111265909 A CN111265909 A CN 111265909A CN 202010219411 A CN202010219411 A CN 202010219411A CN 111265909 A CN111265909 A CN 111265909A
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- 238000002425 crystallisation Methods 0.000 title claims abstract description 133
- 238000001704 evaporation Methods 0.000 title claims abstract description 124
- 230000008020 evaporation Effects 0.000 title claims abstract description 109
- 230000008025 crystallization Effects 0.000 claims abstract description 125
- 230000000694 effects Effects 0.000 claims abstract description 97
- 238000000034 method Methods 0.000 claims abstract description 23
- 230000008569 process Effects 0.000 claims abstract description 6
- 239000007788 liquid Substances 0.000 claims description 290
- 239000002994 raw material Substances 0.000 claims description 195
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 122
- 238000000926 separation method Methods 0.000 claims description 82
- 239000000498 cooling water Substances 0.000 claims description 63
- 239000000463 material Substances 0.000 claims description 34
- 238000010438 heat treatment Methods 0.000 claims description 33
- 239000013078 crystal Substances 0.000 claims description 30
- 238000001816 cooling Methods 0.000 claims description 28
- 238000003756 stirring Methods 0.000 claims description 24
- 239000007787 solid Substances 0.000 claims description 19
- 238000007599 discharging Methods 0.000 claims description 17
- 208000028659 discharge Diseases 0.000 claims description 16
- 230000018044 dehydration Effects 0.000 claims description 14
- 238000006297 dehydration reaction Methods 0.000 claims description 14
- 238000003860 storage Methods 0.000 claims description 8
- 238000009833 condensation Methods 0.000 claims description 7
- 230000005494 condensation Effects 0.000 claims description 7
- 230000001151 other effect Effects 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 10
- ISPYRSDWRDQNSW-UHFFFAOYSA-L manganese(II) sulfate monohydrate Chemical compound O.[Mn+2].[O-]S([O-])(=O)=O ISPYRSDWRDQNSW-UHFFFAOYSA-L 0.000 abstract description 7
- 150000003839 salts Chemical class 0.000 abstract description 7
- 229940118149 zinc sulfate monohydrate Drugs 0.000 abstract description 7
- RNZCSKGULNFAMC-UHFFFAOYSA-L zinc;hydrogen sulfate;hydroxide Chemical compound O.[Zn+2].[O-]S([O-])(=O)=O RNZCSKGULNFAMC-UHFFFAOYSA-L 0.000 abstract description 7
- 238000005265 energy consumption Methods 0.000 abstract description 6
- 239000000126 substance Substances 0.000 abstract description 5
- 239000012266 salt solution Substances 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 17
- 239000012527 feed solution Substances 0.000 description 9
- 238000004140 cleaning Methods 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- 239000011550 stock solution Substances 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000007865 diluting Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000012452 mother liquor Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000003670 easy-to-clean Effects 0.000 description 1
- 238000004945 emulsification Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011133 lead Substances 0.000 description 1
- 238000004094 preconcentration Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000009291 secondary effect Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- 238000010977 unit operation Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0018—Evaporation of components of the mixture to be separated
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/26—Multiple-effect evaporating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/30—Accessories for evaporators ; Constructional details thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0004—Crystallisation cooling by heat exchange
- B01D9/0013—Crystallisation cooling by heat exchange by indirect heat exchange
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0018—Evaporation of components of the mixture to be separated
- B01D9/0027—Evaporation of components of the mixture to be separated by means of conveying fluid, e.g. spray-crystallisation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0059—General arrangements of crystallisation plant, e.g. flow sheets
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G45/00—Compounds of manganese
- C01G45/10—Sulfates
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G9/00—Compounds of zinc
- C01G9/06—Sulfates
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/043—Details
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/048—Purification of waste water by evaporation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D2009/0086—Processes or apparatus therefor
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- Crystallography & Structural Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Hydrology & Water Resources (AREA)
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Abstract
A multi-effect evaporation concentration crystallizer and an evaporation crystallization method relate to the field of chemical equipment. The multi-effect evaporation concentration crystallizer comprises a switchable evaporation concentration crystallization tank group; the switchable evaporation concentration crystallization tank group consists of a crystallization tank X and a crystallization tank Y; a heat exchange coil X is arranged in the crystallizing tank X, a heat exchange coil Y is arranged in the crystallizing tank Y, and the front ends of the heat exchange coil X and the heat exchange coil Y are connected with external steam through pipelines with valves; the inner cavity of the crystallizing tank X is connected with the front end of the heat exchange coil Y through a pipeline with a valve; the inner cavity of the crystallizing tank Y is connected with the front end of the heat exchange coil pipe X through a pipeline with a valve. The salt solution evaporating and crystallizing process is used in multiple effect evaporating and concentrating crystallizer. The invention is suitable for the production requirements of the evaporation concentration crystallization working section of salts such as zinc sulfate monohydrate, manganese sulfate monohydrate and the like, and greatly saves the energy consumption cost of the evaporation concentration crystallization of the salts such as zinc sulfate monohydrate, manganese sulfate monohydrate and the like.
Description
Technical Field
The invention relates to the field of chemical equipment, in particular to a multi-effect evaporation concentration crystallizer and an evaporation concentration crystallization method.
Background
The multi-effect evaporation concentration crystallizer is important unit operation equipment in the production of the chemical industry, has the advantages of energy conservation, environmental protection and the like, and is widely applied to the chemical industry.
However, the conventional multi-effect evaporation concentration crystallizer has the following defects:
1. in consideration of various factors, a tube type or plate type heat exchanger is mostly adopted in a general multi-effect evaporation crystallization process, when crystals are generated in an evaporated substance, an external heating forced circulation mode is generally adopted for preventing the heat exchanger from blocking the tubes and crystallizing, but in the evaporation, concentration and crystallization process of salts such as zinc sulfate monohydrate, manganese sulfate monohydrate and the like, a large amount of crystal solid is generated in a concentrated solution, and in order to meet the technical requirements of centrifugal dehydration of a later section, reduce the amount of mother liquor for centrifugal dehydration, reduce energy consumption and improve productivity, the higher the crystal solid content in the concentrated slurry is required to be, the better the crystal solid content is, and even the crystal solid content is required to reach 800-. Such high crystalline solids concentrate in tubes or plates can easily cause serious problems of crystallization, scaling, tube plugging and plate plugging.
2. The existing production of salts such as zinc sulfate monohydrate and manganese sulfate monohydrate can only adopt a single-effect normal-pressure evaporating pot, a heat exchanger of the single-effect normal-pressure evaporating pot is arranged in the pot, the heat exchange area is limited by the capacity of the pot body and cannot be greatly limited, if the certain scale capacity is reached, a large number of single-effect pots are needed, so that the equipment occupies more workshop space, and the equipment investment is increased.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a multi-effect evaporation concentration crystallizer, which solves the problem that the conventional multi-effect evaporation crystallizer is easy to crystallize and scale in a heat exchanger in the use process, so that the normal use of the multi-effect evaporation crystallizer is influenced.
The technical scheme of the invention is as follows: the switchable multi-effect evaporation concentration crystallizer comprises a switchable evaporation concentration crystallization tank group; the switchable evaporation concentration crystallization tank group consists of at least two crystallization tanks; a heat coil is replaced in each crystallization tank, the front end of each heat exchange coil is connected with primary steam through a pipeline with a valve, and the rear end of each heat exchange coil is used for discharging water vapor after heat exchange; the inner cavity of each crystallization tank is connected with the front ends of the built-in heat exchange coils of the other crystallization tanks through a pipeline with a valve.
The further technical scheme of the invention is as follows: a stirring device is arranged in each crystallization tank;
the device also comprises a raw material liquid pool; the raw material liquid pool is connected with the inner cavity of each crystallizing tank through a pipeline with a valve;
the device also comprises a raw material liquid preheating assembly; the raw material liquid preheating assembly comprises a condensate water pool, a condensate water conveying pump and a preheater which are connected with each other; the condensation water tank is communicated with the rear end of the heat exchange coil; the preheater is arranged on a pipeline between the raw material liquid pool and the inner cavity of the crystallizing tank;
the device also comprises a condensed water gas-liquid separation device; the condensed water gas-liquid separation device comprises a vacuum gas-liquid separation tank A, and the vacuum gas-liquid separation tank A is arranged between the rear end of the heat exchange coil and the condensed water tank;
it also includes a multiple steam discharge treatment assembly; the multiple steam discharging and treating component comprises a condenser, a cooling water tank, a circulating pump B, a water cooling tower, a circulating pump C and a vacuum gas-liquid separation tank B; the condenser is communicated with the inner cavity of each crystallizing tank through a pipeline, the condenser, the cooling water pool and the circulating pump A are communicated with each other to form a cooling water heating loop, the water cooling tower, the circulating pump C and the cooling water pool are communicated with each other to form a cooling water cooling loop, and the vacuum gas-liquid separation tank B is communicated with the condenser through a pipeline.
The technical scheme of the invention is as follows: the switchable multi-effect evaporation concentration crystallizer comprises a switchable evaporation concentration crystallization tank group and a concentration tank; the switchable evaporation concentration crystallization tank group consists of a crystallization tank A and a crystallization tank B, the crystallization tanks A, B are respectively internally provided with heat exchange coils A, B, the front ends of the heat exchange coils A, B are connected with external steam supply through pipelines with valves, and the rear ends of the heat exchange coils A, B are used for discharging water vapor after heat exchange; the inner cavity of the crystallizing tank A is connected with the front end of the heat exchange coil B through a pipeline with a valve; the inner cavity of the crystallizing tank B is connected with the front end of the heat exchange coil A through a pipeline with a valve; the inner cavities of the concentration tanks are respectively connected with the inner cavity of the crystallizing tank A, B.
The further technical scheme of the invention is as follows: the device also comprises a heat exchanger and a raw material liquid pool; a raw material liquid heating loop is arranged between the heat exchanger and the concentration tank, and the heat exchanger is respectively communicated with the inner cavity of the crystallization tank A, B; the raw material liquid pool is connected with an inner cavity of the crystallizing tank A, an inner cavity of the crystallizing tank B and a raw material liquid heating loop through pipelines with valves;
a stirring device A is arranged in the crystallization tank A, and a stirring device B is arranged in the crystallization tank B;
it also includes a triple effect steam condensing assembly; the triple-effect steam condensation component comprises a condenser, a cooling water tank, a circulating pump B, a water cooling tower and a circulating pump C; the condenser is communicated with the inner cavity of the concentration tank, the condenser, the cooling water pool and the circulating pump A are communicated with each other to form a cooling water heat exchange loop, and the water cooling tower, the circulating pump C and the cooling water pool are communicated with each other to form a cooling water cooling loop;
the device also comprises a raw material liquid preheating assembly; the raw material liquid preheating assembly comprises a condensate water pool, a condensate water conveying pump and a preheater which are connected with each other; the condensate water tank is communicated with the rear end of the heat exchange coil A, B; the preheater is arranged on a pipeline between the raw material liquid pool and the inner cavity of the crystallizing tank A, and/or a pipeline between the raw material liquid pool and the inner cavity of the crystallizing tank B, and/or a pipeline between the raw material liquid pool and the raw material liquid heating loop;
it also includes a vapor-liquid separation assembly; the steam-liquid separation component comprises a vacuum gas-liquid separation tank A and a vacuum gas-liquid separation tank B; the vacuum gas-liquid separation tank A is communicated with the rear end of the heat exchange coil A, B; and the vacuum gas-liquid separation tank B is communicated with a condenser of the triple-effect steam condensation assembly and a heat exchanger of the triple-effect raw material liquid heating assembly.
The technical scheme of the invention is as follows: the switchable multi-effect evaporation concentration crystallizer comprises a switchable evaporation concentration crystallization tank group and a concentration tank; the switchable evaporation concentration crystallization tank group consists of a crystallization tank L, a crystallization tank M and a crystallization tank N; a heat exchange coil L, a heat exchange coil M and a heat exchange coil N are respectively arranged in the crystallizing tank L, the crystallizing tank M and the crystallizing tank N; the front ends of the heat exchange coil L, the heat exchange coil M and the heat exchange coil N are connected with external steam supply through pipelines with valves, and the rear ends of the heat exchange coil L, the heat exchange coil M and the heat exchange coil N are all used for discharging water vapor after heat exchange; the inner cavity of the crystallization tank L is connected with the front ends of the heat exchange coil M and the heat exchange coil N through pipelines with valves, the inner cavity of the crystallization tank M is connected with the front ends of the heat exchange coil L and the heat exchange coil N through pipelines with valves, and the inner cavity of the crystallization tank N is connected with the front ends of the heat exchange coil L and the heat exchange coil M through pipelines with valves; the inner cavity of the concentration tank is respectively connected with the inner cavities of the crystallizing tank L, the crystallizing tank M and the crystallizing tank N through pipelines with valves.
The further technical scheme of the invention is as follows: the device also comprises a heat exchanger and a raw material liquid pool; a raw material liquid heating loop is arranged between the heat exchanger and the concentration tank, and the heat exchanger is connected with the inner cavities of the crystallization tank L, the crystallization tank M and the crystallization tank N through pipelines with valves; the raw material liquid pool is connected with a raw material liquid heating loop, the inner cavity of the crystallizing tank L, the inner cavity of the crystallizing tank M and the inner cavity of the crystallizing tank N through pipelines with valves;
a stirring device L, a stirring device M and a stirring device N are respectively arranged in the crystallization tank L, the crystallization tank M and the crystallization tank N;
it also includes a four-effect steam condensing assembly; the four-effect steam condensation component comprises a condenser, a cooling water tank, a circulating pump B, a water cooling tower and a circulating pump C; the condenser is communicated with the inner cavity of the concentration tank, the condenser, the cooling water pool and the circulating pump B are communicated with each other to form a cooling water heat exchange loop, and the water cooling tower, the circulating pump C and the cooling water pool are communicated with each other to form a cooling water cooling loop;
the device also comprises a raw material liquid preheating assembly; the raw material liquid preheating assembly comprises a condensate water pool, a condensate water conveying pump and a preheater which are connected with each other; the condensation water tank is communicated with the rear ends of the heat exchange coil L, the heat exchange coil M and the heat exchange coil N; the preheater is arranged on a pipeline between the raw material liquid pool and the inner cavity of the crystallizing tank L, and/or a pipeline between the raw material liquid pool and the inner cavity of the crystallizing tank M, and/or a pipeline between the raw material liquid pool and the inner cavity of the crystallizing tank N, and/or a pipeline between the raw material liquid pool and the raw material liquid heating loop;
it also includes a vapor-liquid separation assembly; the steam-liquid separation component comprises a vacuum gas-liquid separation tank A and a vacuum gas-liquid separation tank B; the vacuum gas-liquid separation tank A is arranged between the rear end of the heat exchange coil L and the condensate water main pipe, and/or between the rear end of the heat exchange coil M and the condensate water main pipe, and between the rear end of the heat exchange coil N and the condensate water main pipe; the vacuum gas-liquid separation tank B is communicated with the condenser and the heat exchanger to receive the steam discharged by the condenser and the heat exchanger after heat exchange.
The technical scheme of the invention is as follows: a method for evaporating, concentrating and crystallizing salt solution is applied to a multi-effect evaporation concentration crystallizer and comprises the following steps:
s01, controlling the raw material liquid in the raw material liquid pool to enter each tank body in the switchable evaporative concentration crystallization tank group, then introducing steam into the corresponding tank body, enabling each tank body to operate according to each preset effect level, and then starting each accessory component to realize the preheating of the raw material liquid and the treatment of each effect discharge steam;
s02, when the solid content of the crystals in the first effect reaches the required concentration, the first effect is cut to remove scale; firstly, effect-level switching is carried out, a first effect is exchanged with other low-level effects, then the crystallized materials in the previous effect are discharged, then the raw material liquid in the raw material liquid pool is controlled to enter the previous effect, and the crystallized scales in the previous effect are dissolved by utilizing the characteristic that the concentration of the raw material liquid is thinner;
in this step, the previous effect is the effect before the switching effect stage.
The technical scheme of the invention is as follows: the multi-effect evaporation concentration crystallizer comprises a first-effect crystallizing tank A, a first-effect crystallizing tank B, a second-effect evaporating tank, a second-effect heat exchanger and a raw material liquid storage pool;
the first-effect crystallizing tanks A, B are respectively provided with a first-effect heat exchanger, the front end of the first-effect heat exchanger extends out of the tank body to be communicated with external steam supply, and the rear end of the first-effect heat exchanger extends out of the tank body to discharge water vapor after heat exchange; the inner cavities of the first-effect crystallizing tanks A, B are respectively communicated to the second-effect heat exchangers through pipelines;
a raw material liquid heating loop is formed between the two-effect evaporation tank and the two-effect heat exchanger, and the inner cavities of the two-effect evaporation tank are respectively communicated to the inner cavity of the one-effect crystallizing tank A, B through pipelines;
the raw material liquid storage pool is communicated with the inner cavity of the two-effect evaporation tank through a pipeline.
The further technical scheme of the invention is as follows: the raw material liquid preheating heat exchanger is arranged on a pipeline between the raw material liquid storage tank and the two-effect evaporation tank; the rear end of the first-effect heat exchanger is communicated with the raw material liquid preheating heat exchanger through a pipeline.
The invention further adopts the technical scheme that: the first-effect heat exchanger comprises a first-effect coil type heat exchanger arranged inside a first-effect crystallizing tank A and a first-effect jacketed type heat exchanger arranged inside a first-effect crystallizing tank B. .
Embodiments 1, 3, and 4 of the present invention have the following advantages:
1. the method is suitable for the production requirements of the evaporation concentration crystallization working section of salts such as zinc sulfate monohydrate, manganese sulfate monohydrate and the like, and greatly saves the energy consumption cost of the evaporation concentration crystallization of the salts such as zinc sulfate monohydrate, manganese sulfate monohydrate and the like. Compared with the existing single-effect normal-pressure evaporation concentration crystallization equipment for salts such as zinc sulfate monohydrate, manganese sulfate monohydrate and the like, the equipment investment is saved, and the occupied area of the equipment is reduced.
2. Through the switching of various effects, the method for dissolving the crystallization scale by using the raw material liquid can easily remove the crystallization scale in the crystallization tank and ensure the continuous and normal operation of equipment; the evaporated liquid in the crystallization tank flows outside the heat exchange pipe, the crystallization scale can only be attached to the inner wall of the crystallization tank and the outer wall of the heat exchange pipe, only the effect level needs to be switched, the raw material liquid is introduced again to dilute and dissolve the crystallization scale, manual cleaning is not needed, and in addition, when the crystallization scale is dissolved in dilution, the heat exchange evaporation concentration is also carried out simultaneously, so that the two effects are not wrong.
3. Compared with the traditional multiple-effect evaporation concentration crystallizer, the evaporation liquid is enabled to only flow in the evaporation tank by canceling a circulating pump for driving external heat exchange and adopting a stirring device with lower power. On one hand, the crystal is prevented from sinking, scaling and crystallizing, and on the other hand, the energy consumption is reduced.
4. The number of the tank bodies of each effect can be multiple, when any crystallizing tank introduces raw material liquid to dilute, dissolve, scale and crystallize, the rest crystallizing tanks can still work normally, and the whole production line cannot be stopped.
Compared with the prior art, the embodiment 2 of the invention has the following advantages:
the multi-effect evaporator is reasonable in structural design, can enable scaling in a pot to be cleaned simply and easily, does not affect normal production, enables special materials to be suitable for multi-effect production, and achieves the purpose of saving more energy.
The invention is further described below with reference to the figures and examples.
Drawings
FIG. 1 is a schematic structural view of example 1 of the present invention;
FIG. 2 is an enlarged view of a portion of FIG. 1;
FIG. 3 is a schematic structural view of example 2 of the present invention;
FIG. 4 is a schematic structural diagram of embodiment 3 of the present invention;
FIG. 5 is a schematic structural view of example 4 of the present invention;
fig. 6 is a partially enlarged view of fig. 5.
Detailed Description
Example 1:
as shown in figure 1-2, the triple-effect evaporation concentration crystallizer comprises a crystallizing tank A1-1, a crystallizing tank B1-2, a concentrating tank 1-3, a primary steam main 1-41, a secondary steam main 1-42, a tertiary steam main 1-43, a feeding main 1-44, a condensed water main 1-45, a triple-effect raw material liquid heating assembly and a raw material liquid pool 1-6.
A cavity of a crystallization tank A1-1 is internally provided with a heat exchange coil A1-11 and a stirring device A1-12, a main body of the heat exchange coil A1-11 is positioned inside the crystallization tank A1-1, the front end and the rear end of the heat exchange coil A1-11 respectively extend out of the cavity of the crystallization tank A1-1, the front end is respectively communicated with a primary steam header pipe 1-41 and a secondary steam header pipe 1-42 through two pipelines, the rear end is communicated with a condensed water header pipe 1-45, the upper end of the crystallization tank A1-1 is provided with a steam outlet A1-13, a steam outlet A1-13 is respectively communicated with a tertiary steam header pipe 1-43 and a secondary steam header pipe 1-42 through pipelines, the upper end of the crystallization tank A1-1 is provided with a raw material liquid inlet A1-14, and the raw material liquid inlet A1-14 is.
A cavity of a crystallization tank B1-2 is internally provided with a heat exchange coil B1-21 and a stirring device B1-22, a main body of the heat exchange coil B1-21 is positioned inside the crystallization tank B1-2, front and rear ends of the heat exchange coil B1-21 respectively extend out of the cavity of the crystallization tank B1-2, the front end is respectively communicated with a primary steam header pipe 1-41 and a secondary steam header pipe 1-42 through two pipelines, the rear end is communicated with a condensed water header pipe 1-45, the upper end of the crystallization tank B1-2 is provided with a steam outlet B1-23, a steam outlet B1-23 is respectively communicated with a tertiary steam header pipe 1-43 and a secondary steam header pipe 1-42 through pipelines, the upper end of the crystallization tank B1-2 is provided with a raw material liquid inlet B1-24, and the raw material liquid inlet B1-24 is communicated with a.
The upper end of the concentration tank 1-3 is provided with a steam outlet C1-31, the lower end is provided with a semi-concentrated solution outlet 1-32, the side wall is provided with a raw material solution circulating inlet 1-33 and a raw material solution circulating outlet 1-34, and the semi-concentrated solution outlet 1-32 is communicated to the feeding header pipe 1-44 through a pipeline.
The heat exchanger 1-5 is communicated with the tertiary steam main pipe 1-43, and the heat exchanger 1-5 and the concentration tank 1-3 are sequentially connected through a pipeline, a valve and a circulating pump to form a raw material liquid heating loop. The circulation operation of the raw material liquid heating loop can enable the raw material liquid in the concentration tank 1-3 to continuously flow through the heat exchanger 1-5 to exchange heat with high-temperature steam in the heat exchanger 1-5 to increase the temperature. The raw material liquid pool 1-6 is communicated with a raw material liquid heating loop and a feeding main pipe 1-44 through a pipeline with a valve.
Preferably, it also includes a feed solution preheating assembly. The raw material liquid preheating assembly comprises a condensed water pool 1-71, a condensed water delivery pump 1-72 and a preheater 1-73 which are mutually connected. The condensate water tanks 1-71 are communicated with a condensate water main pipe 1-45, and the preheaters 1-73 are communicated with a feeding main pipe 1-45 and a raw material liquid heating loop. The condensate water tanks 1-71 receive high-temperature condensate water from the condensate water header pipes 1-45, and then the high-temperature condensate water is pumped into the preheaters 1-73 through the condensate water conveying pumps 1-72 to preheat raw material liquid in the preheaters 1-73. The feed solution from feed solution tanks 1-6 is preheated by preheaters 1-73 and then fed to the feed solution heating circuit and feed manifolds 1-44.
Preferably, it further comprises a triple effect steam emission treatment assembly; the triple-effect steam discharge processing assembly comprises a condenser 1-81, a cooling water pool 1-82, a circulating pump B1-83, a water cooling tower 1-84, a circulating pump C1-85, a vacuum gas-liquid separation tank B1-86 and a vacuum pump 1-87; the condenser 1-81 is communicated with a steam outlet C1-31 of the concentration tank 1-3, the condenser 1-81, the cooling water pool 1-82 and the circulating pump B1-83 are sequentially communicated to form a cooling water heat exchange loop, the circulating operation of the cooling water heat exchange loop can continuously drive the cooling water in the cooling water pool 1-82 to flow through the condenser 1-81, so that the high-temperature steam in the condenser 1-81 exchanges heat with the cooling water to reduce the temperature and condense. The water cooling towers 1-84, the circulating pump C1-85 and the cooling water pools 1-82 are communicated in sequence to form a cooling water cooling loop. The circulation operation of the cooling water cooling loop can continuously drive the cooling water in the cooling water pool 1-82 to flow through the cooling water tower 1-84 for cooling. The air-liquid separation tanks B1-86 are respectively communicated with the condensers 1-81 and the heat exchangers 1-5 to receive the heat-exchanged water vapor discharged by the condensers 1-81 and the heat exchangers 1-5, and the vacuum pumps 1-87 are communicated with the vacuum air-liquid separation tanks B1-86 to provide negative pressure to drive the steam to flow. Steam discharged from a steam outlet C1-31 of the concentration tank 1-3 continuously enters the condenser 1-81 through a pipeline, exchanges heat with cooling water in the condenser 1-81 to reduce the temperature, finally the steam which is in a gas-liquid mixed state and discharged from the condenser 1-81 enters the vacuum gas-liquid separation tank B1-86 to be subjected to gas-liquid separation treatment, and the separated water and steam are respectively discharged outside.
Preferably, the device further comprises a condensed water gas-liquid separation device. The condensed water gas-liquid separation device comprises a vacuum gas-liquid separation tank A1-91 and a vacuum gas-liquid separation tank B1-92. The vacuum gas-liquid separation tank A1-91 is arranged between the rear end of the heat exchange coil A1-11 and the condensed water main pipe 1-45, and between the rear end of the heat exchange coil B1-21 and the condensed water main pipe 1-45. The vacuum gas-liquid separation tank A1-91 is respectively communicated with the condenser 1-81 and the heat exchanger 1-5. The vacuum gas-liquid separation tank A1-91 is used for carrying out gas-liquid separation treatment on steam discharged by heat exchange of the heat exchange coil A1-11 and the heat exchange coil B1-21, the steam obtained by treatment is discharged outside, and the water obtained by treatment is input into the condensed water header pipe 1-45. And the vacuum gas-liquid separation tank B1-92 is used for carrying out gas-liquid separation treatment on the water vapor discharged by heat exchange of the condenser 1-81 and the heat exchanger 1-5, and the treated steam and water are respectively discharged outside.
The number of the crystallizing tanks A1-1 and B1-2 in the present embodiment may be plural, and is determined according to the requirement of the evaporation amount. But it is necessary to ensure that the number of the crystallizing tanks A1-1 is consistent with that of the crystallizing tanks B1-2, and the specification model of the crystallizing tank A1-1 is completely consistent with that of the crystallizing tank B1-2, so as to facilitate the switching operation of one effect and two effects.
The valve arrangement contained in example 1 is as follows:
the lower end of the crystallizing tank A1-1 is provided with a blanking valve A1-15. An external steam inlet valve A1-16 is arranged on a pipeline between the upper end of the heat exchange coil A1-11 and the primary steam header pipe 1-41. A secondary steam inlet valve A1-17 is arranged on a pipeline between the upper end of the heat exchange coil A1-11 and the secondary steam main pipe 1-42. A tertiary steam discharge valve A1-18 is arranged on a pipeline between a steam outlet A1-13 of the crystallizing tank A1-1 and the tertiary steam header pipe 1-43, and a secondary steam discharge valve A1-19 is arranged on a pipeline between a steam outlet A1-13 of the crystallizing tank A1-1 and the secondary steam header pipe 1-42.
The lower end of the crystallizing tank B1-2 is provided with a blanking valve B1-25. And an external steam inlet valve B1-26 is arranged on a pipeline between the upper end of the heat exchange coil B1-21 and the primary steam header 1-41. A secondary steam inlet valve B1-27 is arranged on a pipeline between the upper end of the heat exchange coil B1-21 and the secondary steam main pipe 1-42. A tertiary steam discharge valve B1-28 is arranged on a pipeline between a steam outlet B1-23 of the crystallization tank B1-2 and the tertiary steam header pipe 1-43, and a secondary steam discharge valve B1-29 is arranged on a pipeline between a steam outlet B1-23 of the crystallization tank B1-2 and the secondary steam header pipe 1-42.
The lower end of the concentration tank 1-3 is provided with a blanking valve C1-35.
The switchable triple-effect evaporation concentration crystallization comprises the following steps:
s01, starting the crystallizing tank A, B:
a. feeding a raw material liquid: closing a blanking valve A1-15 at the lower end of a crystallizing tank A1-1, a blanking valve B1-25 at the lower end of a crystallizing tank B1-2 and a blanking valve C1-35 at the lower end of a triple effect concentration tank 1-3, opening valves and pumps on corresponding feeding routes, and respectively putting the raw material liquid in a raw material liquid pool 1-6 into the crystallizing tank A1-1, the crystallizing tank B1-2 and the triple effect concentration tank 1-3. The feeding route entering the triple-effect concentration tank 1-3 comprises a raw material liquid pool 1-6, a preheater 1-73, a circulating pump A1-52 and a triple-effect heat exchanger 1-51. The feeding route entering the crystallizing tank A1-1 sequentially comprises a raw material liquid pool 1-6, a preheater 1-73 and a feeding header pipe 1-44. The feeding route entering the crystallizing tank B1-2 sequentially comprises a raw material liquid pool 1-6, a preheater 1-73 and a feeding header pipe 1-44. Closing the pump and valve on the corresponding feed line after each tank reaches the specified capacity; when the raw material liquid was fed, the stirring apparatus A1-12 in the crystallizer A1-1 and the stirring apparatus B1-22 in the crystallizer B1-2 were started.
b. Steam feeding: opening a primary steam inlet valve A1-16 and a secondary steam outlet valve A1-19 on a crystallizing tank A1-1, and closing a secondary steam inlet valve A1-17 and a tertiary steam outlet valve A1-18 on a crystallizing tank A1-1; an external steam inlet valve B1-26 and a secondary steam outlet valve B1-29 on the crystallizing tank B1-2 are closed, and a secondary steam inlet valve B1-27 and a tertiary steam outlet valve B1-28 on the crystallizing tank B1-2 are opened.
c. Gas-liquid separation: and opening corresponding valves communicated with the vacuum gas-liquid separation tank A1-91 to enable the vacuum gas-liquid separation tank A1-91 to carry out gas-liquid separation on water vapor exhausted from the crystallization tank A1-1 and the crystallization tank B1-2, feeding the treated water into a tertiary steam header pipe 1-43, and feeding the treated water into a condensate water pool 1-71 through a condensate water header pipe 1-45.
S02, starting and operating a three-effect concentration tank: starting the triple-effect raw material liquid heating assembly to enable the raw material liquid in the raw material heating circulation pipeline to start to circularly flow, and heating the raw material liquid in the triple-effect concentration tank 1-3. The feed solution preheating assembly is activated to preheat the feed solution as it flows through preheaters 1-73. And starting the triple-effect steam condensation component to cool the steam discharged from the triple-effect concentration tank 1-3. And starting the vacuum gas-liquid separation tank B1-92 to perform gas-liquid separation on the water vapor discharged by the three-way heat exchanger 1-51 and the condenser 1-81 on the one hand, and simultaneously providing negative pressure to drive the steam flow in the three-way heat exchanger 1-51 and the condenser 1-81.
S03, one-effect and two-effect switching: when the solid content of the crystal in the crystallizing tank A1-1 reaches the required concentration, switching between the first effect and the second effect, wherein the switching method comprises the following steps: closing an external steam inlet valve A1-16 and a secondary steam outlet valve A1-19 on a crystallizing tank A1-1, opening a secondary steam inlet valve A1-17 and a tertiary steam outlet valve A1-18 on the crystallizing tank A1-1, opening an external steam inlet valve B1-26 and a secondary steam outlet valve B1-29 on a crystallizing tank B1-2, and closing a secondary steam inlet valve B1-27 and a tertiary steam outlet valve B1-28 on a crystallizing tank B1-2; before switching, the crystallizer A1-1 and the crystallizer B1-2 respectively have a first effect and a second effect, and after switching, the crystallizer A1-1 and the crystallizer B1-2 respectively have a second effect and a first effect.
S04, descaling: after the switching of the first effect and the second effect is finished, a blanking valve A1-15 of a crystallizing tank A1-1 is opened, crystallized materials are discharged for centrifugal dehydration, after the materials in the crystallizing tank A1-1 are discharged, the blanking valve A1-15 is closed, a corresponding valve on a feeding line is opened, raw material liquid in a raw material liquid pool 1-6 enters the crystallizing tank A1-1, and crystallization scale on the inner wall of the crystallizing tank A1-1 and crystallization scale on the outer wall of a heat exchange coil A1-11 are dissolved by utilizing the characteristic that the concentration of the raw material liquid is thinner.
And S05, repeating the steps S02-S04 to realize the continuous operation of the triple-effect evaporation concentration crystallizer.
This embodiment utilizes the method that raw materials liquid dissolved crystallization scale deposit through the switching of one effect and two effects, can easily get rid of the inside crystallization scale deposit of evaporating pot (including crystallizer A and crystallizer B) to and the crystallization scale deposit on the heat transfer coil pipe outer wall need not artifical clearance, and, when diluting and dissolving the crystallization scale deposit, heat transfer evaporative concentration also goes on simultaneously, two unmistakable.
Example 2:
as shown in figure 3, the multi-effect evaporative crystallizer comprises a first-effect crystallizing tank A2-1, a first-effect crystallizing tank B2-2, a first-effect coil type heat exchanger 2-3, a first-effect jacketed type heat exchanger 2-4, a second-effect heat exchanger 2-5, a raw material liquid preheating heat exchanger 2-6, a second-effect circulating pump 2-7, a raw material liquid storage pool 2-8, a liquid inlet pump 2-9, a vacuum pump 2-10, a steam-water separator 2-11, a feeding and crystal slurry circulating pump 2-12, a second-effect evaporating tank 2-13 and a tertiary steam condenser 2-14, wherein the first-effect crystallizing tank A2-1 and the first-effect crystallizing tank B2-2 are connected in parallel, the first-effect coil type heat exchanger 2-3 is arranged in the first-effect crystallizing tank A2-2, the first-effect jacketed type heat exchanger 2-4 is arranged in the first-effect crystallizing tank B2, the double-effect heat exchanger 2-5 is fixedly connected with the raw material preheating heat exchanger 2-6, the double-effect heat exchanger 2-5 is fixedly connected with the double-effect circulating pump 2-7, one end of the raw material storage tank 2-8 is provided with a liquid inlet pump 2-9, one end of the vacuum pump 2-10 is fixedly provided with a steam-water separator 2-11, the double-effect evaporation tank 2-13 is fixedly connected with the feeding and crystal slurry circulating pump 2-12, and the tertiary steam condenser 2-14 is connected with the double-effect evaporation tank 2-13.
The first-effect crystallizing tank A2-1, the first-effect crystallizing tank B2-2, the first-effect coil type heat exchanger 2-3 and the first-effect jacketed type heat exchanger 2-4 form a first-effect heat exchanger, the first-effect heat exchanger does not adopt an external heat exchanger, but adopts an internal coil type and an evaporating chamber outer wall jacketed type joint in an evaporating chamber, so that the evaporating chamber and the heat exchanger are designed into an integrated machine structure.
The number of the single-effect evaporation pots is 2 or more than 2, and the purpose is as follows: 1. mainly for matching and balancing the evaporation capacity and the heat transfer area required by the heat exchanger of the back effect evaporator. 2. The device is used for batch operation and better cleaning crystal scales on the heat exchanger.
Briefly describe the workflow of example 2:
firstly, pumping raw materials into each effect evaporation chamber to a certain liquid level from a raw material liquid pool through a raw material liquid inlet pump, then sequentially opening heat supply medium pipeline switches of each heat exchanger in a first effect crystallizing tank A and a first effect crystallizing tank B, a stirrer of the first effect crystallizing tank A and the first effect crystallizing tank B, a secondary steam inlet and outlet switch of a secondary evaporation solution circulating pump and a secondary steam inlet and outlet switch of a secondary effect heat exchanger, a vacuum pump, a feeding and crystal slurry circulating pump, each condenser, a gas-liquid separator and valves on each connecting pipeline, and then regulating and controlling the pressure and the temperature of each effect to enter a normal evaporation concentration state.
And step two, the raw material liquid enters an evaporation chamber of the two-effect evaporation tank after being preheated by the preheater, is sent to the two-effect heat exchanger for heat exchange by a circulating pump and then returns to the two-effect evaporation tank, the two-effect evaporation tank circularly and repeatedly works in the way, and the solution in the two-effect evaporation tank is evaporated and pre-concentrated and then is pumped into the one-effect crystallization tank A and the one-effect crystallization tank B by a pre-concentration feeding and crystal slurry circulating pump, so that continuous feeding and intermittent feeding can be realized. And after the materials in the first-effect crystallizing tank A and the first-effect crystallizing tank B are evaporated and concentrated to reach the required concentration, carrying out centrifugal dehydration, and returning the mother liquor after the centrifugal dehydration to the first-effect crystallizing tank A and the first-effect crystallizing tank B for circular evaporation.
And step three, after external heat supply media of the first-effect crystallizing tank A and the first-effect crystallizing tank B are subjected to heat exchange through the first-effect coil pipe type heat exchanger and the first-effect jacketed type heat exchanger respectively, if the condensed water generated by the water vapor after heat exchange through the heat exchangers enters a condensed water pipeline and then enters a steam-water separator, and then returns to the previous working section for use. If the heat conduction oil is heat conduction oil, the heat conduction oil is returned to the boiler system for recycling after being subjected to heat exchange by the one-effect coil pipe type heat exchanger and the one-effect jacketed type heat exchanger. Under the action of a vacuum pump, secondary steam generated in the first-effect crystallizing tank A and the first-effect crystallizing tank B enters the second-effect heat exchanger through a secondary steam pipeline for heat exchange, then enters the steam-water separator through a condensed water pipeline and then returns to the front working section for use. Under the action of a vacuum pump, tertiary steam generated in the secondary evaporation tank enters a tertiary steam condenser through a tertiary steam pipeline to be condensed into condensed water, and the condensed water enters a steam-water separator through a pipeline and then returns to the previous working section for use. The cooling water entering the tertiary steam condenser pipe is merged into other condensed water recovery devices through pipelines and returns to the previous working section for use.
And step four, the multi-effect evaporator generally adopts two or two evaporation pots which are connected in parallel for use according to the balance calculation and concentration requirements of the evaporation water amount of each effect, when the scaling on the inner walls of the heat exchangers in the first-effect crystallizing tank A and the first-effect crystallizing tank B seriously affects the normal operation, the materials in the first-effect evaporation pot and the second-effect evaporation pot are sequentially and alternately emptied, a feed liquor pump is used for pumping raw material liquor or clean water into the first-effect crystallizing tank A and the first-effect crystallizing tank B, heat is continuously supplied to enable the scaling on the surface of the heat exchanger in the first-effect evaporation pot to be dissolved, and then the pre-concentrated raw material liquor from the second-effect evaporation pot is continuously evaporated and concentrated, and the operation is.
And step five, when the shutdown operation is required, firstly stopping feeding the raw material liquid, closing valves of pipelines of the raw material liquid, stopping a liquid inlet pump of the raw material liquid, continuing the evaporation concentration operation, emptying materials of the two-effect evaporation tank, the two-effect heat exchanger, the one-effect crystallization tank A and the one-effect crystallization tank B in sequence, pumping clear water into the evaporation pots or chambers by using the liquid inlet pump of the raw material liquid, circulating for 2-3 hours, completely dissolving the materials scaling on the pipelines, the valves, the evaporation chambers or pots, the heat exchanger and other parts, closing switches and valves of moving parts, and finishing the shutdown operation.
The embodiment solves the problem of scaling and blockage of the heat exchanger, and enlarges the heat transfer area as much as possible to make up for the problem of insufficient heat transfer area; the circulating pump is saved, and the energy consumption is saved. The present embodiment adds a stirring system, and the purpose of the design is as follows: firstly, preventing the crystal from depositing on the bottom of the pan; secondly, preventing a large amount of scale on the heater from influencing the heat transfer efficiency; thirdly, the solid content of the evaporated liquid can be improved, the productivity and the utilization rate of equipment are improved, the circulation quantity of the mother liquid is reduced, the energy consumption is saved, and the crystallization environment is prevented from being deteriorated.
In the embodiment, a material with a high heat transfer coefficient is adopted as a heater material as much as possible on the premise that the one-effect heat exchanger meets the anti-corrosion requirement and does not influence the product quality, so that the defect of insufficient heat transfer area, such as copper, tin, lead, silver and other materials with high heat transfer coefficients, is overcome, or the surface of the materials is subjected to surface anti-corrosion treatment to adapt to the anti-corrosion requirement.
In this embodiment, the pressure in the single-effect evaporator is ensured to be greater than or equal to the normal pressure as much as possible, and the concentration of the evaporating solution is higher and better under the condition of not influencing the freezing of the evaporator and blocking of the pipeline, so that the design purpose is as follows: firstly, the boiling point temperature of the evaporated solution is increased, and the thermal crystallization material has the characteristics of higher crystallization temperature, higher temperature, coarse crystallization particles, good shape, convenience for dehydration and separation, reduction of the free water content on the surface of the dehydrated crystal, saving of later-stage drying energy and improvement of the capacity of drying equipment; secondly, the higher the concentration is, the more the boiling temperature of the evaporation solution rises, which is beneficial to the volatilization and escape of organic matters in the solution to be more thorough, reduces the viscosity of the evaporation solution, improves the crystal growth environment of the evaporation solution, controls the crystal of the evaporation solution in a good crystallization state, prevents the emulsification phenomenon caused by the fine crystal particles of the thermal crystallization material, and solves the problem that the production equipment is not operated normally.
In the embodiment, two or more evaporation pans are used in parallel in one effect, and the design aims at that: firstly, the heat exchange area of the heat exchanger is increased, because the heat exchangers with built-in coil pipes and jacketed type connection are arranged in the evaporation chamber and on the outer wall of the evaporation chamber, the heat exchange area cannot be made very large due to the limitation of space and operation conditions, and the heat exchange area of the later-effect evaporator can be made very large by adopting an external heat exchanger, so that a single evaporation chamber is usually adopted, and the problem that the heat exchange area is not enough can only be compensated by using the number of the single evaporation chamber; secondly, when the surface of the heat exchanger and the scale in the boiler need to be cleaned, the single-effect evaporation boiler can be cleaned intermittently and alternately without influencing the normal production. The main method for cleaning the surface of the heat exchanger and the scale in the boiler is as follows: when an evaporation pan needs to clean the surface of the heat exchanger and scale in the pan, after materials in the evaporator are placed, the evaporation solution stock solution or clear water is added into the evaporator, and the evaporation solution stock solution and the clear water can dissolve the scale on the surface of the heat exchanger and in the evaporation pan. When the dissolution is complete, the multi-effect conventional operation is continued. The design ensures that the scale in the boiler is easy to clean and control, the normal production is not influenced, and the normal operation can be realized no matter how high the concentration or solid content of the evaporating solution in the evaporating boiler is.
Example 3:
as shown in FIG. 4, the switchable two-effect evaporation concentration crystallizer comprises a switchable evaporation concentration crystallization tank set, primary steam pipes 3-31, secondary steam pipes 3-32, raw material liquid pipes 3-33, condensate pipes 3-34 and raw material liquid pools 1-35.
The switchable evaporation concentration crystallizing tank group consists of a crystallizing tank X3-1 and a crystallizing tank Y3-2.
The crystallization tank X3-1 is internally provided with a heat exchange coil X3-11, the front end of the heat exchange coil X3-11 is communicated to a primary steam pipe 3-31 through a pipeline with an external steam inlet valve X3-12, and is communicated to a secondary steam pipe 3-32 through a pipeline with a secondary steam inlet valve X3-13. The rear end of the heat exchange coil X3-11 is communicated with the condensate pipe 3-34 through a pipeline to discharge the vapor after heat exchange. The upper end of the crystallizing tank X3-1 is provided with a steam outlet X3-14 communicated to the inner cavity of the crystallizing tank X3-1, and the steam outlet X3-14 is communicated to a secondary steam pipe 3-32 through a pipeline with a secondary steam discharge valve X3-15. The crystallizer X3-1 is provided with a feed inlet X3-16 communicated with the inner cavity of the crystallizer, a feed inlet X3-16 is communicated with the raw material liquid pipe 3-33 through a pipeline, and the lower end of the crystallizer X3-1 is provided with a discharge outlet X3-17 communicated with the inner cavity of the crystallizer.
The crystallization tank Y3-2 is internally provided with a heat exchange coil Y3-21, the front end of the heat exchange coil Y3-21 is communicated to a primary steam pipe 3-31 through a pipeline with an external steam inlet valve Y3-22, and is communicated to a secondary steam pipe 3-32 through a pipeline with a secondary steam inlet valve Y3-23. The rear ends of the heat exchange coils Y3-21 are communicated with the condensate pipes 3-34 through pipelines to discharge the water vapor after heat exchange. The upper end of the crystallizing tank Y3-2 is provided with a steam outlet Y3-24 communicated to the inner cavity of the crystallizing tank Y3-2, and the steam outlet Y24 is communicated to the secondary steam pipe 3-32 through a pipeline with a secondary steam discharge valve Y3-25. The crystallizing tank Y3-2 is provided with a feed inlet Y3-26 communicated with the inner cavity of the crystallizing tank, the feed inlet Y3-26 is communicated with the raw material liquid pipe 3-33 through a pipeline, and the lower end of the crystallizing tank Y3-2 is provided with a discharge outlet Y3-27 communicated with the inner cavity of the crystallizing tank.
The raw material liquid pool 3-35 is communicated with the raw material liquid pipe 3-33 through a pipeline with a valve.
Preferably, the crystallizer X3-1 is provided with a stirring device X3-18, and the crystallizer Y3-2 is provided with a stirring device Y3-28. The stirring devices X3-18 and Y3-28 allow the evaporated liquid to flow only in the corresponding tanks, and can prevent the crystal from sinking and scaling to some extent.
Preferably, the device further comprises a condensed water gas-liquid separation device; the condensed water gas-liquid separation device comprises a vacuum gas-liquid separation tank A3-5, wherein the vacuum gas-liquid separation tank A3-5 is arranged at the rear ends of a heat exchange coil X3-11 and a heat exchange coil Y3-21 and is used for carrying out gas-liquid separation treatment on water vapor discharged by the heat exchange coil X3-11 and the heat exchange coil Y3-21, the treated gas is discharged outside, and the treated liquid is input into a condensed water pipe 3-34.
Preferably, it also comprises a two-effect steam emission treatment component; the double-effect steam discharge processing assembly comprises a condenser 3-61, a cooling water pool 3-62, a circulating pump B3-63, a water cooling tower 3-64, a circulating pump C3-65, a vacuum gas-liquid separation tank B3-66 and a vacuum pump 3-67; the condenser 3-61 is communicated with inner cavities of the crystallizing tanks X3-1 and Y3-2 through pipelines, the condenser 3-61, the cooling water pool 3-62 and the circulating pump A3-63 are communicated with each other to form a cooling water heating loop, the water cooling tower 3-64, the circulating pump C3-65 and the cooling water pool 3-62 are communicated with each other to form a cooling water cooling loop, the vacuum gas-liquid separation tank B3-66 is communicated with the condenser 3-61 and used for receiving water vapor discharged by the condenser 3-61 after heat exchange, and the vacuum pump 3-67 is communicated with the vacuum gas-liquid separation tank B3-66 and used for providing negative pressure to drive steam to flow. The circulating operation of the cooling water heating loop can continuously drive the cooling water in the cooling water pool 3-62 to flow through the condenser 3-61, so that the high-temperature steam in the condenser 3-61 exchanges heat with the cooling water to reduce the temperature and condense. The circulation operation of the cooling water cooling loop can continuously drive the cooling water in the cooling water pool 3-62 to flow through the cooling water tower 3-64 for cooling. Steam discharged from a crystallizing tank X3-1 or a crystallizing tank Y3-2 continuously enters a condenser 3-61 through a pipeline, exchanges heat with cooling water in the condenser 3-61 to reduce the temperature, the steam which is discharged from the condenser 3-61 and is in a gas-liquid mixed state enters a vacuum gas-liquid separation tank B3-66 to be subjected to gas-liquid separation treatment, and the separated water and the separated steam are respectively discharged outside.
Preferably, the device also comprises a raw material liquid preheating assembly; the raw material liquid preheating assembly comprises a condensate water pool 3-41, a condensate water conveying pump 3-42 and a preheater 3-43 which are mutually connected; the condensate water tank 3-41 is communicated with a vacuum gas-liquid separation tank A3-5 through a condensate water pipe 3-34; the preheater 3-43 is arranged on the pipeline between the raw material liquid pool 3-35 and the raw material liquid pipe 3-33. The raw material liquid preheating assembly is used for preheating raw material liquid discharged from a raw material liquid pool 3-35 at a normal temperature, the heat source of the preheater 3-43 is water vapor discharged from the rear end of the heat exchange coil X3-11 and the rear end of the heat exchange coil Y3-21 after heat exchange, when the raw material liquid discharged from the raw material liquid pool 3-35 passes through the preheater 3-43, the raw material liquid exchanges heat with the water vapor with relatively high temperature in the preheater 3-43 to increase the temperature, the raw material liquid is discharged from the preheater 3-43 and then is input into the raw material liquid pipes 3-33, and finally the raw material liquid pipes 3-33 are respectively conveyed into the inner cavities of the crystallization tanks X3-1 and Y3-2.
The switchable two-effect evaporation concentration crystallization comprises the following steps:
s01, starting the crystallizing tank X, Y:
a. feeding a raw material liquid: closing crystallizing tank X3-1, discharge outlet X3-17 and discharge outlet Y3-27 at the lower end of crystallizing tank Y3-2, opening corresponding valves and pumps, and adding the raw material liquid in raw material liquid pool 3-35 into crystallizing tank X3-1 and crystallizing tank Y3-2. After the crystallizer X3-1 and crystallizer Y3-2 reach the specified capacity, the corresponding pumps and valves are closed, the raw material liquid is stopped from being put in, and when the raw material liquid is added, the stirring devices X3-18 and Y3-28 are started to stir the raw material liquid.
b. Steam feeding: opening a primary steam inlet valve X3-12 and a secondary steam outlet valve X3-15 on the crystallizing tank X3-1, and closing a secondary steam inlet valve X3-13. And opening a secondary steam inlet valve Y3-23 and a secondary steam outlet valve Y3-25 on the crystallizing tank Y3-2, and closing an external steam inlet valve Y3-22. At the moment, externally supplied steam enters the heat exchange coil X3-11 from the front end of the heat exchange coil X3-11 to heat the raw material liquid in the crystallizer X3-1, the steam generated by evaporation of the raw material liquid in the inner cavity of the crystallizer X3-1 sequentially enters the heat exchange coil Y3-21 through the steam outlet X3-14 and the secondary steam pipe 3-32 and the front end of the heat exchange coil Y3-21 to heat the raw material liquid in the crystallizer Y3-2, and the steam generated by evaporation of the raw material liquid in the inner cavity of the crystallizer Y3-2 is discharged into the secondary steam pipe 3-32.
c. Gas-liquid separation: and starting a secondary steam discharge treatment assembly to cool the steam in the secondary steam pipes 3-32 and separate the steam from gas and liquid, and then discharging the steam outside respectively. And starting a vacuum gas-liquid separation tank A3-5 to carry out gas-liquid separation treatment on the water vapor discharged from the rear ends of the heat exchange coils X3-11 and Y3-21. Starting the raw material liquid preheating assembly to preheat the raw material liquid discharged from the raw material liquid pool 3-35.
S02, one-effect and two-effect switching: when the solid content of the crystal in the crystallizing tank X3-1 reaches the required concentration, switching between the first effect and the second effect, wherein the switching method comprises the following steps: closing a primary steam inlet valve X3-12 on a crystallizing tank X3-1, opening a secondary steam inlet valve X3-13, opening a primary steam inlet method Y3-22 on a crystallizing tank Y3-2, and closing a secondary steam inlet valve Y3-23; before switching, crystallizers X3-1 and Y3-2 are respectively one-effect and two-effect, and after switching, crystallizers X, Y are respectively two-effect and one-effect.
S03, descaling: opening a discharge port X3-17, discharging crystallized materials, carrying out centrifugal dehydration, closing a discharge port X3-17 after the materials in a crystallizing tank X3-1 are discharged, opening a corresponding valve and a corresponding pump to enable raw material liquid in a raw material liquid pool 3-35 to enter the crystallizing tank X3-1, and dissolving crystalline scales on the inner wall of the crystallizing tank X3-1 and crystalline scales on the outer wall of a heat exchange coil X3-11 by utilizing the characteristic that the concentration of the raw material liquid is thinner.
And S04, repeating the steps 2-3 to realize the continuous operation of the double-effect evaporation concentration crystallizer.
This embodiment utilizes the method that the more rare stock solution of concentration dissolves the crystallization scale deposit through the switching of an effect and two effects, can easily get rid of the inside crystallization scale deposit of crystallizer X, Y in turn to and the crystallization scale deposit on the heat exchange coil outer wall, need not manual cleaning, and, when diluting and dissolving the crystallization scale deposit, heat transfer evaporative concentration also goes on simultaneously, two unmistakable.
Example 4:
as shown in the figure 5-6, the switchable four-effect evaporation concentration crystallizer comprises a crystallizing tank L4-1, a crystallizing tank M4-2, a crystallizing tank N4-3, a concentrating tank 4-4, a heat exchanger 4-5, a primary steam main 4-61, a secondary steam main 4-62, a tertiary steam main 4-63, a quaternary steam main 4-64, a feeding main 4-65, a condensed water main 4-66 and a raw material liquid pool 4-67.
The crystallizing tanks L4-1, M4-2 and N4-3 are respectively internally provided with heat exchange coil pipes L4-11, M4-21 and N4-31, the front ends of the heat exchange coil pipes L4-1 are communicated with primary steam main pipes 4-61 through pipelines with valves A4-12, pipelines with valves B4-13 are communicated with secondary steam main pipes 4-62, and pipelines with valves C4-14 are communicated with tertiary steam main pipes 4-63. The front end of the heat exchange coil M4-21 is communicated with a primary steam main 4-61 through a pipeline with a valve D4-22, a pipeline with a valve E4-23 is communicated with a secondary steam main 4-62, and a pipeline with a valve F4-24 is communicated with a tertiary steam main 4-63. The front ends of the heat exchange coils N4-31 are communicated with the primary steam manifolds 4-61 through pipelines with valves G4-32, the pipelines with valves H4-33 are communicated with the secondary steam manifolds 4-62, and the pipelines with valves I4-34 are communicated with the tertiary steam manifolds 4-63. The upper ends of the inner cavities of the crystallization tanks L4-1, M4-2 and N4-3 are respectively provided with a steam outlet L, M, N, the steam outlet L is communicated with a secondary steam main pipe 4-62 through a pipeline with a valve J4-15, communicated with a tertiary steam main pipe 4-63 through a pipeline with a valve K4-16, and communicated with a quaternary steam main pipe 4-64 through a pipeline with a valve L4-17. The steam outlet M is communicated with the secondary steam main 4-62 through a pipeline with a valve M4-25, communicated with the tertiary steam main 4-63 through a pipeline with a valve N4-26 and communicated with the quaternary steam main 4-64 through a pipeline with a valve O4-27. The steam outlet N is communicated with the secondary steam main 4-62 through a pipeline with a valve P4-35, communicated with the tertiary steam main 4-63 through a pipeline with a valve Q4-36 and communicated with the quaternary steam main 4-64 through a pipeline with a valve R4-37. The lower ends of the crystallization tanks L4-1, M4-2 and N4-3 are respectively provided with feed openings L4-18, M4-28 and N4-38, and the feed openings L4-18, M4-28 and N4-38 are respectively communicated to condensate water header pipes 4-66 through pipelines. The upper ends of the crystallization tanks L4-1, M4-2 and N4-3 are respectively provided with a liquid inlet L, M, N, and the liquid inlet L, M, N is respectively communicated to the feeding header pipes 4-65 through pipelines.
The lower end of the concentration tank 4-4 is provided with a liquid outlet 4-41, and the liquid outlet 4-41 is communicated to a feeding header pipe 4-65 through a pipeline. The inner cavity of the concentration tank 4-4 is connected with the heat exchanger 4-5 through a pipeline, a valve and a circulating pump to form a raw material liquid heating loop. The heat exchanger 4-5 is communicated with the quartic steam header 4-64. The raw material liquid pool 4-67 is communicated to a raw material liquid heating loop and a feeding main pipe 4-65 through a pipeline with a valve.
Preferably, the crystallization tanks L4-1, M4-2 and N4-3 are respectively provided with stirring devices L4-19, M4-29 and N4-39. The stirring devices L4-19, M4-29 and N4-39 enable the evaporated liquid to flow only in the corresponding tank, and can prevent the crystal from sinking and scaling to a certain extent.
Preferably, it also comprises a four-effect steam emission treatment component; the four-effect steam discharge treatment component comprises 4-71 parts of a condenser, 4-72 parts of a cooling water pool, 4-73 parts of a circulating pump B, 4-74 parts of a water cooling tower, 4-75 parts of a circulating pump C, 4-76 parts of a vacuum gas-liquid separation tank B and 4-77 parts of a vacuum pump. The condenser 4-71 is communicated with the inner cavity of the concentration tank 4-4, the condenser 4-71, the cooling water pool 4-72 and the circulating pump B4-73 are communicated with each other to form a cooling water heat exchange loop, and the water cooling tower 4-74, the circulating pump C4-75 and the cooling water pool 4-72 are communicated with each other to form a cooling water cooling loop. The air-liquid separation tank B4-76 is respectively communicated with the condenser 4-71 and the heat exchanger 4-5 to receive the heat-exchanged water vapor discharged by the condenser 4-71 and the heat exchanger 4-5, and the vacuum pump 4-77 is communicated with the vacuum air-liquid separation tank B4-76 to provide negative pressure to drive the steam to flow. The circulating operation of the cooling water heat exchange loop can continuously drive the cooling water in the cooling water pool 4-72 to flow through the condenser 4-71, so that the high-temperature steam in the condenser 4-71 exchanges heat with the cooling water to reduce the temperature and condense. The circulation operation of the cooling water cooling loop can continuously drive the cooling water in the cooling water pool 4-72 to flow through the cooling water tower 4-74 for cooling. Steam discharged from the concentration tank 4-3 continuously enters the condenser 4-71 through a pipeline, the steam exchanges heat with cooling water in the condenser 4-71 to reduce the temperature, the steam which is discharged from the condenser 4-71 and is in a gas-liquid mixed state enters the vacuum gas-liquid separation tank B4-76 to be subjected to gas-liquid separation treatment, and the separated water and steam are respectively discharged outside.
Preferably, the device further comprises a condensed water gas-liquid separation device; the condensed water gas-liquid separation device comprises a vacuum gas-liquid separation tank A4-91; the vacuum gas-liquid separation tank A4-91 is arranged at the rear ends of the heat exchange coils L4-11, M4-21 and N4-31. The vacuum gas-liquid separation tank A4-91 is used for carrying out gas-liquid separation treatment on steam discharged by heat exchange of the heat exchange coil pipes L4-11, M4-21 and N4-31, the treated steam is discharged outside, and the treated water is input into the condensed water header pipe 4-66.
Preferably, the device also comprises a raw material liquid preheating assembly; the raw material liquid preheating assembly comprises a condensate water pool 4-81, a condensate water conveying pump 4-82 and a preheater 4-83 which are connected with each other; the condensed water tanks 4-81 are connected with a vacuum gas-liquid separation tank A4-91 through pipelines with valves; the preheater 4-83 is arranged on a pipeline between the raw material liquid pool 4-67 and the crystallizing tank L4-1, the crystallizing tank M4-2, the crystallizing tank N4-3 and the raw material liquid heating loop. The condensate water tank 4-81 receives high-temperature condensate water from the condensate water header pipe 4-66, and the high-temperature condensate water is pumped into the preheater 4-83 through the condensate water conveying pump 4-82 to preheat the raw material liquid in the preheater 4-83. The feed solution from feed solution reservoir 4-67 is preheated by preheater 4-83 and then delivered to the feed solution heating circuit and feed header 4-65.
The method can switch the first effect, the second effect and the third effect in the four-effect evaporation concentration crystallization process and comprises the following descaling steps:
the switching method comprises the following steps:
the state before switching, the crystallizing tank L4-1, the crystallizing tank M4-2 and the crystallizing tank N4-3 are respectively one effect, two effects and three effects. Valves A4-12 and D4-22 on a crystallizing tank L4-1 are opened, valves B4-13, C4-14, E4-23 and F4-24 are closed, valves I4-34, G4-32, J4-15 and L4-17 on a crystallizing tank M4-2 are closed, valves H4-33 and K4-16 are opened, valves M4-25, N4-26, Q4-36 and P4-35 on a crystallizing tank N4-3 are closed, and valves O4-27 and R4-37 are opened. Steam in the primary steam header pipe 4-61 enters a heat exchange coil L4-11, steam in the inner cavity of a crystallizing tank L4-1 is discharged into a secondary steam header pipe 4-62 and then enters a heat exchange coil M4-21, steam in the inner cavity of a crystallizing tank M4-2 is discharged into a tertiary steam header pipe 4-63 and then enters a heat exchange coil N4-31, and steam in the inner cavity of a crystallizing tank N4-31 is discharged into a quaternary steam header pipe 4-64 and then enters a heat exchanger 4-5.
The first switching can be performed when the solid content of the crystals in the first effect (crystallizing tank L4-1) reaches the required concentration: opening valves G4-32 and J4-15 on a crystallizing tank M4-2, closing valves I4-34, H4-33, K4-16 and L4-17, closing valves C4-14, A4-12, D4-22 and F4-24 on a crystallizing tank L4-1, opening valves B4-13 and E4-23, and not adjusting valves on a crystallizing tank N4-26. After the switching, steam in the primary steam header pipe 4-61 enters the heat exchange coil pipe M4-21, steam in the inner cavity of the crystallizing tank M4-2 is discharged into the secondary steam header pipe 4-62 and then enters the heat exchange coil pipe L4-11, steam in the inner cavity of the crystallizing tank L4-1 is discharged into the tertiary steam header pipe 4-63 and then enters the heat exchange coil pipe N4-31, and steam in the inner cavity of the crystallizing tank N4-3 is discharged into the quaternary steam header pipe 4-64 and then enters the heat exchanger 4-5. After the switching, the crystallizing tank M4-2, the crystallizing tank L4-1 and the crystallizing tank N4-3 respectively have one effect, two effects and three effects.
The operation for descaling the crystallizing tank L4-1 was as follows: opening a valve on a feed opening L4-18 at the lower end of a crystallizing tank L4-1, discharging crystallized materials, performing centrifugal dehydration, closing the valve on the feed opening L4-18 after the materials in the crystallizing tank L4-1 are discharged, opening a corresponding valve on a feed route, enabling a raw material liquid in a raw material liquid pool 4-67 to enter the crystallizing tank L4-1, and dissolving the crystallized scale on the inner wall of the crystallizing tank L4-1 and the crystallized scale on the outer wall of a heat exchange coil L4-11 by utilizing the characteristic that the concentration of the raw material liquid is thinner.
And (3) switching for the second time, wherein after the solid content of the crystals in the first effect (crystallizing tank M4-2) reaches the required concentration, the second switching can be carried out: opening valves M4-25 and P4-35 on a crystallizing tank N4-3, closing valves O4-27, N4-26, Q4-36 and R4-37, opening valves H4-33 and K4-16 on a crystallizing tank M4-2, closing valves I4-34, G4-32, J4-15 and L4-17, and not adjusting a valve on a crystallizing tank L4-1. After the switching, steam in the primary steam header pipe 4-61 enters the heat exchange coil pipe N4-31, steam in the inner cavity of the crystallizing tank N4-3 is discharged into the secondary steam header pipe 4-62 and then enters the heat exchange coil pipe L4-11, steam in the inner cavity of the crystallizing tank L4-1 is discharged into the tertiary steam header pipe 4-63 and then enters the heat exchange coil pipe M4-21, and steam in the inner cavity of the crystallizing tank M4-2 is discharged into the quaternary steam header pipe 4-64 and then enters the heat exchanger 4-5. After the switching, the crystallizing tank N4-3, the crystallizing tank L4-1 and the crystallizing tank M4-2 respectively have one effect, two effects and three effects.
The operation for descaling the crystallizing tank M4-2 was as follows: opening a valve on a feed opening M4-28 at the lower end of a crystallizing tank M4-2, discharging crystallized materials, performing centrifugal dehydration, closing the valve on the feed opening M4-28 after the materials in the crystallizing tank M4-2 are discharged, opening a corresponding valve on a feed line, enabling a raw material liquid in a raw material liquid pool 4-67 to enter the crystallizing tank M4-2, and dissolving crystalline scales on the inner wall of the crystallizing tank M4-2 and crystalline scales on the outer wall of a heat exchange coil M4-21 by utilizing the characteristic that the concentration of the raw material liquid is thinner.
And (3) switching for the third time, and when the solid content of the crystals in the first effect (crystallizing tank N4-3) reaches the required concentration, switching for the third time: the switching back to the initial state is not repeated, and after the switching, the crystallizing tank L4-1, the crystallizing tank M4-2 and the crystallizing tank N4-3 respectively have one effect, two effects and three effects.
The operation for descaling the crystallizing tank N4-3 is as follows: opening a valve on a feed opening N4-38 at the lower end of a crystallizing tank N4-3, discharging crystallized materials, performing centrifugal dehydration, closing the valve on the feed opening N4-38 after the materials in the crystallizing tank N4-3 are discharged, opening a corresponding valve on a feed line, enabling a raw material liquid in a raw material liquid pool 4-67 to enter the crystallizing tank N4-3, and dissolving crystalline scales on the inner wall of the crystallizing tank N4-3 and crystalline scales on the outer wall of a heat exchange coil N4-31 by utilizing the characteristic that the concentration of the raw material liquid is thinner.
According to the invention, through the switching of the first effect, the second effect and the third effect, and the method of dissolving the crystallization scale by using the raw material liquid with relatively low concentration, the crystallization scale in the crystallization tank L, M, N and the crystallization scale on the outer wall of the heat exchange coil N4-31 can be easily and alternately removed, manual cleaning is not needed, and heat exchange, evaporation and concentration are simultaneously carried out when the crystallization scale is diluted and dissolved, so that the two effects are not wrong.
Claims (10)
1. A switchable multi-effect evaporation concentration crystallizer is characterized in that: comprises a switchable evaporation concentration crystallization tank group; the switchable evaporation concentration crystallization tank group consists of at least two crystallization tanks; a heat coil is replaced in each crystallization tank, the front end of each heat exchange coil is connected with primary steam through a pipeline with a valve, and the rear end of each heat exchange coil is used for discharging water vapor after heat exchange; the inner cavity of each crystallization tank is connected with the front ends of the heat exchange coil pipes arranged in the other crystallization tanks through a pipeline with a valve.
2. The switchable multi-effect evaporative concentration crystallizer of claim 1, wherein: it also comprises a concentration tank and a heat exchanger; the inner cavity of the concentration tank is respectively connected with the inner cavity of each crystallization tank, and a raw material liquid heating loop is arranged between the heat exchanger and the concentration tank; and a stirring device is arranged in each crystallizing tank.
3. A switchable multi-effect evaporative concentration crystallizer as claimed in claim 1 or 2, characterized in that: the system also comprises a raw material liquid pool, a condensed water gas-liquid separation device and a steam discharge treatment assembly; the raw material liquid pool is connected with the inner cavity of the crystallizing tank and the raw material liquid heating loop through a pipeline with a valve; the condensed water gas-liquid separation device comprises a vacuum gas-liquid separation tank A, and the vacuum gas-liquid separation tank A is connected to the rear end of the heat exchange coil; the steam discharging and treating component comprises a condenser, a cooling water pool, a circulating pump B, a water cooling tower, a circulating pump C, a vacuum gas-liquid separating tank B and a vacuum pump; the condenser is communicated with the inner cavity of the concentration tank through a pipeline, the condenser, the cooling water pool and the circulating pump A are communicated with each other to form a cooling water heating loop, the water cooling tower, the circulating pump C and the cooling water pool are communicated with each other to form a cooling water cooling loop, the vacuum gas-liquid separation tank B is communicated with the condenser and the heat exchanger, and the vacuum pump is communicated with the vacuum gas-liquid separation tank B.
4. The switchable multi-effect evaporative concentration crystallizer of claim 3, wherein: the device also comprises a raw material liquid preheating assembly; the raw material liquid preheating assembly comprises a condensate water pool, a condensate water conveying pump and a preheater which are connected with each other; the condensate water tank is communicated with the vacuum gas-liquid separation tank A; the preheater is arranged on a pipeline between the raw material liquid pool and the inner cavity of the crystallization tank and/or a pipeline between the raw material liquid pool and the raw material liquid heating loop.
5. A multi-effect evaporation concentration crystallization method is applied to a multi-effect evaporation concentration crystallizer and is characterized by comprising the following steps:
s01, controlling the raw material liquid in the raw material liquid pool to enter each effect tank body, and then introducing steam to the corresponding tank body to enable each tank body to operate according to a preset effect level;
s02, when the solid content of the crystals in the first-effect tank reaches the required concentration, switching the first effect with other effect levels, emptying the crystallized materials in the previous-effect tank, controlling the raw material liquid to enter the previous-effect tank, and dissolving the crystallized scale in the previous-effect tank and the crystallized scale on the outer wall of the heat exchange coil by utilizing the characteristic that the concentration of the raw material liquid is thinner.
6. The switchable multi-effect evaporative concentration crystallization method of claim 5, characterized in that: the switchable triple-effect evaporation concentration crystallization comprises the following steps:
s01, starting the crystallizing tank A, B:
a. feeding a raw material liquid: closing a feeding valve A at the lower end of the crystallizing tank A, a feeding valve B at the lower end of the crystallizing tank B and a feeding valve C at the lower end of the triple-effect concentration tank, opening valves and pumps on corresponding feeding lines, and respectively putting the raw material liquid in the raw material liquid pool into the crystallizing tank A, the crystallizing tank B and the triple-effect concentration tank; closing the pump and valve on the corresponding feed line after each tank reaches the specified capacity; starting a stirring device A in a crystallizing tank A and a stirring device B in a crystallizing tank B when raw material liquid is fed;
b. steam feeding: opening a primary steam inlet valve A and a secondary steam outlet valve A on the crystallizing tank A, and closing a secondary steam inlet valve A and a tertiary steam outlet valve A on the crystallizing tank A; closing a primary steam inlet valve B and a secondary steam outlet valve B on the crystallizing tank B, and opening a secondary steam inlet valve B and a tertiary steam outlet valve B on the crystallizing tank B;
c. gas-liquid separation: opening a corresponding valve communicated with the vacuum gas-liquid separation tank A to enable the vacuum gas-liquid separation tank A to carry out gas-liquid separation on water vapor discharged from the crystallization tank A and the crystallization tank B, feeding the treated steam into a tertiary steam main pipe, and feeding the treated water into a condensate water tank through a condensate water main pipe;
s02, starting and operating a three-effect concentration tank: starting the triple-effect raw material liquid heating assembly to enable the raw material liquid in the raw material heating circulation pipeline to start to circularly flow, and heating the raw material liquid in the triple-effect concentration tank; starting the raw material liquid preheating assembly to preheat the raw material liquid when the raw material liquid flows through the preheater; starting the triple-effect steam condensation component, and cooling the steam discharged from the triple-effect concentration tanks 1-3; starting the vacuum gas-liquid separation tank B, performing gas-liquid separation on the water vapor discharged by the three-effect heat exchanger and the condenser on the one hand, and providing negative pressure to drive the steam in the three-effect heat exchanger and the condenser to flow;
s03, one-effect and two-effect switching: when the solid content of the crystals in the crystallizing tank A reaches the required concentration, switching between the first effect and the second effect, wherein the switching method comprises the following steps: closing an external steam inlet valve A and a secondary steam outlet valve A on the crystallizing tank A, opening a secondary steam inlet valve A and a tertiary steam outlet valve A on the crystallizing tank A, opening a primary steam inlet valve B and a secondary steam outlet valve B on the crystallizing tank B, and closing a secondary steam inlet valve B and a tertiary steam outlet valve B on the crystallizing tank B; before switching, the crystallizing tank A and the crystallizing tank B respectively have a first effect and a second effect, and after switching, the crystallizing tank A and the crystallizing tank B respectively have the second effect and the first effect;
s04, descaling: after the switching between the first effect and the second effect is finished, opening a blanking valve A of a crystallizing tank A, discharging crystallized materials, and performing centrifugal dehydration, closing the blanking valve A after the discharging of the materials in the crystallizing tank A is finished, opening a corresponding valve on a feeding line, enabling a raw material liquid in a raw material liquid pool to enter the crystallizing tank A, and dissolving crystallization scale on the inner wall of the crystallizing tank A and the crystallization scale on the outer wall of the heat exchange coil A by utilizing the characteristic that the concentration of the raw material liquid is thinner;
and S05, repeating the steps S02-S04 to realize the continuous operation of the triple-effect evaporation concentration crystallizer.
7. The switchable multi-effect evaporative concentration crystallization method of claim 5, characterized in that: the switchable two-effect evaporation concentration crystallization comprises the following steps:
s01, starting the crystallizing tank X, Y:
a. feeding a raw material liquid: closing the crystallizing tank X, a discharge port X and a discharge port Y at the lower end of the crystallizing tank Y, opening corresponding valves and pumps, and adding the raw material liquid in the raw material liquid pool into the crystallizing tank X and the crystallizing tank Y; after the crystallization tank X and the crystallization tank Y reach the specified capacity, closing the corresponding pump and valve, stopping putting the raw material liquid, and starting the stirring device X, Y to stir the raw material liquid when the raw material liquid is added;
b. steam feeding: opening a primary steam inlet valve X and a secondary steam outlet valve X on the crystallizing tank X, and closing the secondary steam inlet valve X;
opening a secondary steam inlet valve Y and a secondary steam outlet valve Y on the crystallizing tank Y, and closing a primary steam inlet valve Y;
c. gas-liquid separation: starting a secondary steam discharge processing assembly to cool the steam in the secondary steam pipe and separate the steam from gas and liquid, and then respectively discharging the steam outside; starting the vacuum gas-liquid separation tank A to carry out gas-liquid separation treatment on the water vapor discharged from the rear end of the heat exchange coil X, Y; starting a raw material liquid preheating assembly to preheat the raw material liquid discharged from the raw material liquid pool;
s02, one-effect and two-effect switching: when the solid content of the crystals in the crystallizing tank X reaches the required concentration, switching between the first effect and the second effect, wherein the switching method comprises the following steps: closing a primary steam inlet valve X on the crystallizing tank X, opening a secondary steam inlet valve X, opening a primary steam inlet method Y on the crystallizing tank Y, and closing a secondary steam inlet valve Y;
s03, descaling: opening a discharge port X, discharging crystallized materials, performing centrifugal dehydration, closing the discharge port X after the materials in the crystallizing tank X are discharged, opening a corresponding valve and a corresponding pump to enable the raw material liquid in a raw material liquid pool to enter the crystallizing tank X, and dissolving the crystallized scale on the inner wall of the crystallizing tank X and the crystallized scale on the outer wall of the heat exchange coil X by utilizing the characteristic that the concentration of the raw material liquid is thinner;
and S04, repeating the steps 2-3 to realize the continuous operation of the double-effect evaporation concentration crystallizer.
8. The switchable multi-effect evaporative concentration crystallization method of claim 5 or 6, characterized by: the method can switch the first effect, the second effect and the third effect in the four-effect evaporation concentration crystallization process and comprises the following descaling steps:
the initial state, the crystallizing tank L, the crystallizing tank M and the crystallizing tank N are respectively one effect, two effect and three effect, a valve A, D on the crystallizing tank L is opened, a valve B, C, E, F is closed, a valve I, G, J, L on the crystallizing tank M is closed, a valve H, K is opened, a valve M, N, Q, P on the crystallizing tank N is closed, and a valve O, R is opened; steam in the primary steam main pipe enters a heat exchange coil pipe L, steam in the inner cavity of the crystallization tank L is discharged into a secondary steam main pipe and then enters a heat exchange coil pipe M, steam in the inner cavity of the crystallization tank M is discharged into a tertiary steam main pipe and then enters a heat exchange coil pipe N, and steam in the inner cavity of the crystallization tank N is discharged into a quartic steam main pipe and then enters a heat exchanger;
after the solid content of the crystal in the first-effect crystallizing tank L reaches the required concentration, opening a valve G, J on the crystallizing tank M, closing a valve I, H, K, L, closing a valve C, A, D, F on the crystallizing tank L, opening a valve B, E, and not adjusting a valve on the crystallizing tank N; after switching, the crystallizing tank M, the crystallizing tank L and the crystallizing tank N respectively have a first effect, a second effect and a third effect;
descaling the crystallizing tank L, opening a valve on a feed opening L at the lower end of the crystallizing tank L, discharging crystallized materials, performing centrifugal dehydration, closing the valve on the feed opening after the materials in the crystallizing tank L are discharged, opening a corresponding valve on a feed line, enabling a raw material liquid in a raw material liquid tank to enter the crystallizing tank L, and dissolving crystalline scales on the inner wall of the crystallizing tank L and crystalline scales on the outer wall of the heat exchange coil L by utilizing the characteristic that the concentration of the raw material liquid is thinner;
and (3) switching for the second time, and after the solid content of the crystals in the first-effect crystallizing tank M after the first switching reaches the required concentration, switching for the second time: opening a valve M, P on the crystallizing tank N, closing valves O, N4-26 and Q, R, opening a valve H, K on the crystallizing tank M, closing a valve I, G, J, L, and not adjusting a valve on the crystallizing tank L; after switching, the crystallizing tank N, the crystallizing tank L and the crystallizing tank M respectively have a first effect, a second effect and a third effect;
descaling the crystallizing tank M, opening a valve on a feed opening M at the lower end of the crystallizing tank M, discharging crystallized materials, performing centrifugal dehydration, closing the valve on the feed opening M after the materials in the crystallizing tank M are discharged, opening a corresponding valve on a feed line, enabling a raw material liquid in a raw material liquid tank to enter the crystallizing tank M, and dissolving crystalline scales on the inner wall of the crystallizing tank M and crystalline scales on the outer wall of the heat exchange coil M by utilizing the characteristic that the concentration of the raw material liquid is thinner;
and switching for the third time, wherein after the solid content of the crystals in the primary crystallization tank N after the second switching reaches the required concentration, the third switching can be performed: switching to an initial state, wherein the crystallization tank L, the crystallization tank M and the crystallization tank N respectively have a first effect, a second effect and a third effect after switching;
the descaling method comprises the following steps that descaling is conducted on a crystallizing tank N, a valve on a feed opening N at the lower end of the crystallizing tank N is opened, crystallized materials are discharged to be centrifugally dewatered, after the materials in the crystallizing tank N are discharged, the valve on the feed opening N is closed, a corresponding valve on a feed line is opened, raw material liquid in a raw material liquid tank enters the crystallizing tank N, and crystallization scales on the inner wall of the crystallizing tank N and on the outer wall of a heat exchange coil N are dissolved by utilizing the characteristic that the concentration of the raw material liquid is relatively dilute.
9. A multi-effect evaporation concentration crystallizer, which is characterized in that: comprises a first-effect crystallizing tank A, a first-effect crystallizing tank B, a second-effect evaporating tank, a second-effect heat exchanger and a raw material liquid storage pool;
the first-effect crystallizing tanks A, B are respectively provided with a first-effect heat exchanger, the front end of the first-effect heat exchanger extends out of the tank body to be communicated with external steam supply, and the rear end of the first-effect heat exchanger extends out of the tank body to discharge water vapor after heat exchange; the inner cavities of the first-effect crystallizing tanks A, B are respectively communicated to the second-effect heat exchangers through pipelines;
a raw material liquid heating loop is formed between the two-effect evaporation tank and the two-effect heat exchanger, and the inner cavities of the two-effect evaporation tank are respectively communicated to the inner cavity of the one-effect crystallizing tank A, B through pipelines;
the raw material liquid storage pool is communicated with the inner cavity of the two-effect evaporation tank through a pipeline.
10. The multi-effect evaporative concentration crystallizer of claim 9, wherein: the raw material liquid preheating heat exchanger is arranged on a pipeline between the raw material liquid storage tank and the two-effect evaporation tank; the rear end of the first-effect heat exchanger is communicated with the raw material liquid preheating heat exchanger through a pipeline; the first-effect heat exchanger comprises a first-effect coil type heat exchanger arranged inside a first-effect crystallizing tank A and a first-effect jacketed type heat exchanger arranged inside a first-effect crystallizing tank B.
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| CN114100166A (en) * | 2021-10-21 | 2022-03-01 | 中石化宁波工程有限公司 | Switchable salt solution multi-effect concentration evaporation system and efficiency reduction operation method thereof |
| CN114917601A (en) * | 2022-06-30 | 2022-08-19 | 广西埃索凯循环科技有限公司 | Zinc sulfate solution concentrating device based on steam heating and concentrating process thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114100166A (en) * | 2021-10-21 | 2022-03-01 | 中石化宁波工程有限公司 | Switchable salt solution multi-effect concentration evaporation system and efficiency reduction operation method thereof |
| CN114917601A (en) * | 2022-06-30 | 2022-08-19 | 广西埃索凯循环科技有限公司 | Zinc sulfate solution concentrating device based on steam heating and concentrating process thereof |
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