CN111924915A - Negative pressure multiple-effect evaporation treatment salt-containing sewage system based on Venturi effect - Google Patents
Negative pressure multiple-effect evaporation treatment salt-containing sewage system based on Venturi effect Download PDFInfo
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- 238000001704 evaporation Methods 0.000 title claims abstract description 59
- 230000008020 evaporation Effects 0.000 title claims abstract description 53
- 230000000694 effects Effects 0.000 title claims abstract description 52
- 239000010865 sewage Substances 0.000 title claims abstract description 36
- 150000003839 salts Chemical class 0.000 title claims abstract description 12
- 239000007788 liquid Substances 0.000 claims abstract description 38
- 238000003860 storage Methods 0.000 claims abstract description 8
- 230000009467 reduction Effects 0.000 claims abstract description 5
- 238000002347 injection Methods 0.000 claims description 46
- 239000007924 injection Substances 0.000 claims description 46
- 239000012530 fluid Substances 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 230000008859 change Effects 0.000 claims description 14
- 238000012546 transfer Methods 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 10
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 6
- 238000004364 calculation method Methods 0.000 claims description 6
- 239000011780 sodium chloride Substances 0.000 claims description 6
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- 238000010438 heat treatment Methods 0.000 description 7
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- 238000004458 analytical method Methods 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 239000013505 freshwater Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
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- 230000005494 condensation Effects 0.000 description 1
- 230000006837 decompression Effects 0.000 description 1
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- 238000010612 desalination reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
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- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000013401 experimental design Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000520 microinjection Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
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- C02F1/00—Treatment of water, waste water, or sewage
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Abstract
The invention discloses a system for treating salt-containing sewage through negative-pressure multi-effect evaporation based on a Venturi effect, which comprises an original sewage storage pool, a first-effect heat exchange system, a steam source, a first gas-liquid separator, a negative pressure device, a second-effect heat exchange system, a second gas-liquid separator, a vacuum pump and a condenser. This negative pressure multiple-effect evaporation treatment contains salt sewage system based on venturi effect, can produce the low pressure at the spray tube room when high-pressure steam passes through the jet, make the pressure reduction in the gas-liquid separator exit that links to each other with the jet, compare traditional vacuum pump negative pressure multiple-effect evaporation system and know, adopt negative pressure device's multiple-effect evaporation system, a set of vacuum apparatus and a condenser have been saved simultaneously, and negative pressure device drive steam is one-effect exhaust steam, vacuum pump and condenser energy consumption have been saved, new energy consumption has not been introduced, the operation energy consumption of multi-effect evaporator has been reduced effectively, the economy of multi-effect evaporator operation has been guaranteed.
Description
Technical Field
The invention relates to the technical field of sewage treatment systems, in particular to a negative-pressure multi-effect evaporation salt-containing sewage treatment system based on a Venturi effect.
Background
The sewage treatment is a process for purifying sewage to meet the water quality requirement of discharging the sewage into a certain water body or reusing the sewage, the multi-effect evaporation is a series evaporation operation using secondary steam of a previous effect as heating steam of a next effect, in the multi-effect evaporation, the operating pressure, the corresponding heating steam temperature and the solution boiling point of each effect are sequentially reduced, the multi-effect evaporation method is widely used in the fields of sewage treatment, seawater desalination and the like, and the principle is that in the multi-effect evaporator, multiple flash evaporation is carried out on the treated sewage or seawater, and the secondary steam generated in each effect is used as a heat source of the next effect for utilization.
The traditional method adopts a vacuum pump to create a low-pressure environment for evaporation, and has complex pipeline, high running power consumption and unfavorable economical efficiency for the running of a multi-effect evaporator, so that a negative pressure evaporation device needs to be optimized, and a more economical and feasible negative pressure multi-effect evaporation system is provided.
Disclosure of Invention
Technical problem to be solved
Aiming at the defects of the prior art, the invention provides a system for treating saline sewage through negative pressure multi-effect evaporation based on a Venturi effect, and solves the problems that a pipeline for evaporation in a low-pressure environment created by a vacuum pump in a traditional multi-effect evaporation method is complex, high in running power consumption and not beneficial to the running economy of a multi-effect evaporator.
(II) technical scheme
In order to achieve the purpose, the invention is realized by the following technical scheme: a negative-pressure multi-effect evaporation treatment saline sewage system based on Venturi effect comprises an original sewage storage pool, a first-effect heat exchange system, a steam source, a first gas-liquid separator, a second-effect heat exchange system, a second gas-liquid separator, a vacuum pump and a condenser, wherein the interior of the original sewage storage pool is connected with the interior of the first-effect heat exchange system through a pipeline, the interior of the first-effect heat exchange system is respectively connected with the interiors of the steam source and the first gas-liquid separator through a pipeline, the interior of the first-effect heat exchange system is connected with the interior of a negative pressure device through a pipeline, the negative pressure device comprises a three-way device, a high-pressure steam inlet is formed in the left end of the three-way device, an injection port is formed in the three-way device, the interior of the injection port is communicated with one end of an air outlet of the gas-liquid separator, a mixed steam outlet is formed, the inside of the injection port is communicated with the inside of the mixed steam outlet, the inside of the negative pressure device is connected with the inside of the first gas-liquid separator through a guide pipe, and the inside of the negative pressure device is connected with the inside of the two-effect heat exchange system through a pipeline.
Preferably, the interior of the two-effect heat exchange system is respectively connected with the interiors of the first gas-liquid separator, the second gas-liquid separator and the condenser through pipelines.
Preferably, the inside of the second gas-liquid separator is connected to the inside of a vacuum pump through a pipe, and the inside of the vacuum pump is connected to the inside of the condenser through a pipe.
Preferably, the invention also discloses a method for calculating the pressure of the injection port of the negative pressure device, which specifically comprises the following steps:
s1, the change of the flow rate, pressure and state of high-pressure fluid in the variable cross-section pipeline is used for generating ejection negative pressure, in the ejection process, ejection flow is a steam-water mixture, the fluid is assumed to be uniform and ideal, and the relationship between the fluid flow and the ejection flow is as follows:
according to the ideal fluid continuity equation, the following conditions are obtained:
s2, obtained according to two formulas in S1
According to a special form of bernoulli's theorem, for a fully gas compressible isoentropy flow, its bernoulli equation is:
s3, the fluid variables of the air inlet and the air outlet of the injection port in the negative pressure device satisfy the following formula:
wherein
Order to
Then
Therefore, the calculation formula of the pressure of the injection port is as follows:
preferably, in the step S1,
the delta p refers to the pressure difference before and after the hole, the unit is Pa, A refers to the area of the hole opening, the unit is square meter, and the rho refers to the density of the fluid, and the unit is kg/m3Mu denotes the flow coefficient, depending on the outlet configuration of the nozzle, q1Refers to the flow rate of the fluid, in m3/s。
Preferably, in the step S1,
q2means the nozzle flow rate in m3D denotes the nozzle opening diameter in m and V denotes the steam flow rate in m/s.
Preferably, the step S2 is executed,
gamma is temperature direct reduction rate, psi is potential energy of volume vertical field, rho is density of injected fluid, unit is kg/m3V denotes the flow rate of the injected fluid, which is equal to the nozzle outlet flow rate according to the homogeneous flow theory, and C denotes a constant.
Preferably, the step S3 is executed,
q refers to the total amount of fluid flowing out of the injection port, namely the suction volume, and the unit is m3/s，
p denotes the normal pressure in Pa, p2The unit of the pressure of the injected port is Pa.
(III) advantageous effects
The invention provides a negative pressure multiple-effect evaporation salt-containing sewage treatment system based on a Venturi effect. Compared with the prior art, the method has the following beneficial effects:
(1) the negative-pressure multi-effect evaporation treatment saline sewage system based on the Venturi effect comprises a tee joint device through a negative pressure device, a high-pressure steam inlet is formed in the left end of the tee joint device, an injection port is formed in the tee joint device, the inside of the injection port is communicated with one end of an air outlet of a gas-liquid separator, a mixed steam outlet is formed in the right end of the tee joint device, the high-pressure steam inlet is communicated with the inside of the injection port, the inside of the injection port is communicated with the inside of the mixed steam outlet, when the high-pressure steam passes through the injection port, low pressure can be generated in a spray pipe chamber due to the Venturi effect, the pressure of the pressure at the outlet of the gas-liquid separator connected with the injection port is reduced, so that the steam generation condition is enhanced, the evaporation capacity is increased, and meanwhile, the drainage steam generating the Venturi effect is used as, compared with the traditional vacuum pump negative pressure multi-effect evaporation system, the multi-effect evaporation system adopting the negative pressure device saves one set of vacuum equipment and one condenser, and the negative pressure device drives steam to be one effect exhaust steam, so that the energy consumption of the vacuum pump and the condenser is saved, new energy consumption is not introduced, the operation energy consumption of the multi-effect evaporator is effectively reduced, and the economical efficiency of the operation of the multi-effect evaporator is ensured.
(2) This negative pressure multiple effect evaporation treatment contains salt sewage system based on venturi effect, through in steam ejector, working medium and heat-carrying medium all are steam, the high-temperature highly compressed working steam is as the power supply of ejector, it is thus obvious, negative pressure device optimization can promote in a plurality of process field, high pressure multiple effect evaporation system, require under the suitable condition of heating steam, still have certain pressure after the heat transfer of last effect and ensure the device injection effect, installation negative pressure device does not produce other influences to multiple effect evaporation system's sewage treatment effect, play water quality of water satisfies emission standard and industrial demand.
Drawings
FIG. 1 is a flow chart of a system for treating saline sewage by negative pressure multi-effect evaporation according to the invention;
FIG. 2 is a schematic view of the structure of the negative pressure device of the present invention;
FIG. 3 is a graph of steam consumption versus high pressure steam pressure for the present invention;
FIG. 4 is a graph of the relationship between the vapor absorption and the high pressure vapor pressure of the present invention;
FIG. 5 is a diagram showing the simulation effect of the ejector nozzle of the negative pressure device according to the present invention;
FIG. 6 is a graph showing the variation of the centerline pressure of the vacuum apparatus of the present invention;
FIG. 7 is a system diagram of an experiment of the present invention;
FIG. 8 is a graph showing the variation of the first effective pressure according to the present invention;
FIG. 9 is a graph showing the change in the energy efficiency of the vacuum pump and the negative pressure device according to the present invention;
FIG. 10 is a graph showing the change of the fresh water ratio according to the present invention;
figure 11 is a graph of the enthalpy of evaporation according to the invention.
In the figure, 1-raw sewage storage pool, 2-one-effect heat exchange system, 3-steam source, 4-gas-liquid separator I, 5-negative pressure device, 51-tee joint device, 52-high pressure steam inlet, 53-injection port, 54-mixed steam outlet, 6-two-effect heat exchange system, 7-gas-liquid separator II, 8-vacuum pump and 9-condenser.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1 to 11, an embodiment of the present invention provides a technical solution: the utility model provides a negative pressure multiple effect evaporation treatment contains salt sewage system based on venturi effect, including former sewage storage pond 1, one imitate heat transfer system 2, steam source 3, vapour and liquid separator 4, two imitate heat transfer system 6, vapour and liquid separator two 7, vacuum pump 8 and condenser 9, and the inside of negative pressure device 5 passes through the internal connection of pipe and vapour and liquid separator 4, the inside of negative pressure device 5 passes through the internal connection of pipeline and two imitate heat transfer system 6, the inside of two imitate heat transfer system 6 passes through the pipeline and respectively with the internal connection of vapour and liquid separator two 7, and the inside of vapour and liquid separator two 7 passes through the pipeline and the internal connection of vacuum pump 8, the inside of vacuum pump 8 passes through the pipeline and the internal connection of condenser 9, the inside of former sewage storage pond 1 passes through the pipeline and the internal connection of one imitate heat transfer system 2, and the inside of one imitate heat transfer system 2 passes through the pipeline respectively with steam source 3, The internal connection of the first gas-liquid separator 4, the internal connection of the first effective heat exchange system 2 and the negative pressure device 5 is achieved through a pipeline, the negative pressure device 5 comprises a tee joint device 51, a high-pressure steam inlet 52 is formed in the left end of the tee joint device 51, an injection port 53 is formed in the tee joint device 51, the injection port 53 is communicated with one end of an air outlet of the first gas-liquid separator 4, a mixed steam outlet 54 is formed in the right end of the tee joint device 51, the high-pressure steam inlet 52 is communicated with the injection port 53, the injection port 53 is communicated with the mixed steam outlet 54, and meanwhile, the content which is not described in detail in the specification belongs to the prior art which is known to a person skilled in the art.
The invention also discloses a method for calculating the pressure of the injection port of the negative pressure device, which comprises the following steps:
s1, the change of the flow rate, pressure and state of high-pressure fluid in the variable cross-section pipeline is used for generating ejection negative pressure, in the ejection process, ejection flow is a steam-water mixture, the fluid is assumed to be uniform and ideal, and the relationship between the fluid flow and the ejection flow is as follows:
according to the ideal fluid continuity equation, the following conditions are obtained:
s2, according toTwo formulas in S1 can be obtained
According to a special form of bernoulli's theorem, for a fully gas compressible isoentropy flow, its bernoulli equation is:
s3, the fluid variables of the air inlet and the air outlet of the injection port 53 in the negative pressure device 5 satisfy the following formula:
wherein
Order to
Then
Therefore, the calculation formula of the pressure of the injection port is as follows:
in the present invention, in step S1,
the delta p refers to the pressure difference before and after the hole, the unit is Pa, A refers to the area of the hole opening, the unit is square meter, and the rho refers to the density of the fluid, and the unit is kg/m3Mu denotes the flow coefficient, depending on the outlet configuration of the nozzle, q1Refers to the flow rate of the fluid, in m3/s。
In the present invention, in step S1,
q2means the nozzle flow rate in m3D denotes the nozzle opening diameter in m and V denotes the steam flow rate in m/s.
In the invention, the stepsIn the step of S2, the step of,
gamma is temperature direct reduction rate, psi is potential energy of volume vertical field, rho is density of injected fluid, unit is kg/m3V denotes the flow rate of the injected fluid, which is equal to the nozzle outlet flow rate according to the homogeneous flow theory, and C denotes a constant.
In the present invention, in step S3,
q refers to the total amount of fluid flowing out of the injection port, namely the suction volume, and the unit is m3/s，
p denotes the normal pressure in Pa, p2The unit of the pressure of the injected port is Pa.
System energy conservation analysis
The multi-effect evaporator operation mode is decompression operation, for the evaporation of guaranteeing follow-up devices such as two-effect triple-effect, negative pressure cryogenic distillation technique is adopted usually, the purpose of reducing evaporating temperature is reached through the evaporating pressure who satisfies a plurality of grades, when one-effect evaporating pressure is lower, need use a series of low pressure evaporation plant such as vacuum pump, vacuum lead-in jar, condenser for the evaporating temperature that reduces the tail effect, this great increase laboratory bench manufacturing cost and area, and caused considerable equipment energy consumption, the efficiency calculates as follows:
for a medium-high pressure multiple-effect evaporation system, because of the limitation of the heat exchange performance of a heat exchanger, the first-effect steam exhaust steam still has higher pressure and temperature, if the first-effect steam exhaust steam is mixed with new steam generated by the first effect and then input into the next effect, the heating effect of the second effect can be improved, meanwhile, because the pressure of the first-effect steam exhaust is higher, the first-effect steam exhaust steam is used as driving steam to promote the first-effect gas-liquid separation device to complete low-pressure evaporation, the evaporation effect of the first effect can be further improved, based on the optimization thought, the system utilizes the Venturi tube principle to design a small injection device, utilizes the injection effect generated when the first-effect steam exhaust steam passes through a micro injection tube to guide water steam separated from the first-effect gas-liquid separation device to be mixed, the two mixed water steam is input into the second effect as new steam for heat exchange, a vacuum device and a condensing device are saved on the traditional design thought, the, the energy efficiency analysis after modification was as follows:
by comparing the energy efficiency formula, the improved evaporation system increases useful work QInjection of steam heatAnd save WElectricity consumptionAnd the energy utilization rate is obviously improved.
Effect simulation analysis
Effect simulation of the negative pressure device: the diameter of a nozzle chamber of the negative pressure device is 90mm, the diameter of a drainage opening is 10mm, the diameter of a nozzle is 1.2mm, 1.5mm and 2mm, and simulation calculation is carried out under the conditions of 0.15MPa, 0.20MPa, 0.25MPa and 0.30MPa to obtain simulation values of steam consumption and steam absorption of the negative pressure device.
Simulation values of different nozzles
It can be seen from the simulation data that the steam consumption and the steam absorption of the venturi tube are mainly affected by the injection pressure and the diameter of the nozzle, the larger the injection pressure is, the smaller the diameter of the nozzle is, the better the injection effect is, it can be seen from fig. 3 that in the negative pressure device, the steam consumption increment is obvious along with the increase of the high pressure steam pressure, it can be seen from fig. 4 that the steam absorption of the device increases along with the decrease of the caliber of the nozzle inside the device, and the steam flow decreases, the increase of the steam absorption is beneficial to the increase of the steam evaporation capacity of the gas-liquid separation device, the decrease of the steam flow is not beneficial to the recycling of the waste steam waste heat, the decrease of the utilization of the waste steam is not beneficial to the increase of the energy saving rate of the device, therefore, in the experimental design, the pressure change in the simulation should be adopted as the experimental data, the device with the larger caliber is, the device is ensured to reflect larger difference in energy consumption data, so that the energy-saving effect of the device can be observed visually.
A Venturi tube with the nozzle diameter of 2mm is selected as an experimental device, the pressure change situation around the nozzle is simulated by utilizing simulation software, a simulation effect graph of pressure distribution at each position in the device is obtained, the graph is shown in figure 5, and it can be seen from figure 6 that an obvious low-pressure area exists around the outlet of the nozzle, and the pressure of the low-pressure area is far smaller than the pressure at the inlet and the pressure at the tail of the device.
Effect simulation of an evaporation system: the simulation research of the evaporation effect characteristic of a multi-effect evaporator system is carried out on the basis of a self-balancing module in Aspenplus software, the physical property method adopts an ELECNRTL method, a pressure transmission module is used as a device simulation model, the device model is set after a negative pressure device is installed in a one-effect gas-liquid separation air-out mode, the raw water flow is set to be 25kg/h, the steam flow is 45kg/h, a 2mm nozzle is adopted in an experiment, and the water making ratio changes along with the saturated steam pressure and the injection pressure as follows:
system water making ratio analog value provided with Venturi effect negative pressure device
System effect experiment verification
The multi-effect evaporation experiment table designed at this time uses Aspenplus simulation software in advance to carry out design simulation on a double-effect evaporator with heating steam at 110-140 ℃, obtains simulation data of water generation ratio changing along with saturated steam pressure under a given heat exchange area, ensures that various equipment parameters are superior to simulation parameters in the selection process of experimental equipment, and ensures safe and stable operation of experimental devicesThe experiment table of the multi-effect evaporator comprises: the system comprises a steam source device, an evaporation device, a gas-liquid separation device and a condensation device, wherein the steam source device is a 0.15t small-sized gas boiler, the evaporator device is a customized double-corrugated-pipe heat exchanger, the design pressure is 5.0MPa, the test pressure is 0.1MPa-0.3MPa, and the total heat exchange area is 0.24m2The gas-liquid separation device is a gas-liquid separator with a standard structure, the condensing device is an air-cooled condenser, the device adopts a 2mm nozzle, the steam parameters are ensured to be stable by selecting the above equipment, meanwhile, the equipment is convenient to install, the parameters have certain allowance to ensure the safety of the experiment, the experiment system is shown in figure 7, salt-containing sewage TDS of a petrochemical enterprise is taken by the salt-containing sewage used in the experiment, and main electrolyte is Na+、K+、Ca2+、Cl-The mass fraction of the sewage stock solution is 30%, the sewage mass flow is 25kg/h, the temperature of a sewage inlet in the experiment is 25 ℃, and the experiment is carried out by taking saturated steam of 0.15MPa, 0.20MPa, 0.25MPa and 0.30MPa as heating steam in sequence in the actual operation process.
Experimental data: after the energy-saving evaporation device is installed according to the experimental system diagram and successfully debugged, the heating steam pressure is adjusted in sequence to carry out experiments, and the experimental data are as follows:
system experiment value of negative pressure device
In order to verify the energy efficiency change of the system, a frequency conversion vacuum pump and other low-pressure evaporation equipment are arranged in the first-effect device of the experimental device to carry out a comparison experiment, the energy efficiency ratio is calculated according to an energy efficiency ratio calculation formula, and the experimental result is as follows:
energy efficiency comparison value of vacuum pump and negative pressure device
According to the pressure change, in simulation and experiment, along with the increase of injection steam pressure, the evaporation pressure in the single-effect gas-liquid separator is reduced, but the speed of the reduction of the evaporation pressure in the experiment process is faster, and the analysis reason is as follows: the experimental device is a closed container, the steam density is higher than that of air, and the simulation calculation formula is tacitly recognized as an open ideal fluid, so that the experimental data is reduced quickly, the energy efficiency change shows that the energy efficiency of the evaporation unit is obviously improved after the negative pressure device is used for replacing vacuum equipment, the energy efficiency increasing amplitude is increased along with the increase of the steam pressure, an effective pressure change diagram is shown in fig. 8, and an energy efficiency change diagram of the vacuum pump and the negative pressure device is shown in fig. 9.
As shown in fig. 10 and 11, as the injection pressure increases, the water making ratio increases, but the increase rate decreases continuously, wherein fig. 10 is a water making ratio change diagram, fig. 11 is an evaporation enthalpy diagram, and analysis on evaporation enthalpy changes shows that the evaporation enthalpy increases continuously with the decrease of the evaporation pressure, thereby causing the evaporation effect to be poor, the water making ratio change curve in the diagram tends to be flat after 0.20MPa, the injection steam pressure is increased from 0.20MPa to 0.25MPa through accounting, the fresh water yield is only increased by 3.02 kg, the fresh water yield increase speed is more than the pressure section of 0.15MPa to 0.20MPa, the attenuation exceeds 80%, thereby showing that the economic effect of the device is greatly attenuated after 0.20MPa pressure, the injection pressure should not increase continuously in practical application, the water yield of the high-salinity wastewater increases year by year due to wide sources, the water amount increases year by year, the pollutant in the high-salinity wastewater discharge requirement is removed, and therefore, the experimental goal is to produce pure distilled water, the experiment finds that the components of the final condensed water are the same as those of the atmospheric evaporation and do not contain salt electrolyte, and the negative pressure device is proved not to have other influences on the experimental product.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
1. The utility model provides a negative pressure multiple effect evaporation treatment contains salt sewage system based on venturi effect, includes former sewage storage pond (1), one imitates heat transfer system (2), steam source (3), vapour and liquid separator (4), two imitate heat transfer system (6), vapour and liquid separator two (7), vacuum pump (8) and condenser (9), the inside of former sewage storage pond (1) is through the internal connection of pipeline with one imitate heat transfer system (2) to the inside of one imitate heat transfer system (2) is through the internal connection of pipeline respectively with steam source (3), vapour and liquid separator (4), its characterized in that: the interior of the primary heat exchange system (2) is connected with the interior of the negative pressure device (5) through a pipeline, the negative pressure device (5) comprises a three-way device (51), the left end of the three-way device (51) is provided with a high-pressure steam inlet (52), the three-way device (51) is internally provided with an injection port (53), the inside of the injection port (53) is communicated with one end of the air outlet of the first gas-liquid separator (4), the right end of the three-way device (51) is provided with a mixed steam outlet (54), the high-pressure steam inlet (52) is communicated with the inside of the injection port (53), the inside of the injection port (53) is communicated with the inside of the mixed steam outlet (54), the interior of the negative pressure device (5) is connected with the interior of the gas-liquid separator I (4) through a conduit, and the interior of the negative pressure device (5) is connected with the interior of the two-effect heat exchange system (6) through a pipeline.
2. The negative-pressure multi-effect evaporation treatment saline sewage system based on the Venturi effect as claimed in claim 1, wherein: the interior of the two-effect heat exchange system (6) is respectively connected with the interiors of the gas-liquid separator I (4), the gas-liquid separator II (7) and the condenser (9) through pipelines.
3. The negative-pressure multi-effect evaporation treatment saline sewage system based on the Venturi effect as claimed in claim 1, wherein: the interior of the gas-liquid separator II (7) is connected with the interior of the vacuum pump (8) through a pipeline, and the interior of the vacuum pump (8) is connected with the interior of the condenser (9) through a pipeline.
4. The method for calculating the pressure of the injection port of the negative pressure device according to claim 1, characterized by comprising the following steps: the method specifically comprises the following steps:
s1, the change of the flow rate, pressure and state of high-pressure fluid in the variable cross-section pipeline is used for generating ejection negative pressure, in the ejection process, ejection flow is a steam-water mixture, the fluid is assumed to be uniform and ideal, and the relationship between the fluid flow and the ejection flow is as follows:
according to the ideal fluid continuity equation, the following conditions are obtained:
s2, obtained according to two formulas in S1
According to a special form of bernoulli's theorem, for a fully gas compressible isoentropy flow, its bernoulli equation is:
s3, the fluid variables of the air inlet and the air outlet of the internal injection port (53) of the negative pressure device (5) satisfy the following formula:
wherein
Order to
Then
Therefore, the calculation formula of the pressure of the injection port is as follows:
5. the method for calculating the pressure of the injection port of the negative pressure device according to claim 4, wherein the method comprises the following steps: in the step S1, in the above step,
the delta p refers to the pressure difference before and after the hole, the unit is Pa, A refers to the area of the hole opening, the unit is square meter, and the rho refers to the density of the fluid, and the unit is kg/m3Mu denotes the flow coefficient, depending on the outlet configuration of the nozzle, q1Refers to the flow rate of the fluid, in m3/s。
6. The method for calculating the pressure of the injection port of the negative pressure device according to claim 4, wherein the method comprises the following steps: in the step S1, in the above step,
q2refers to the nozzle flow in m3/s, d refers to the nozzle opening diameter in m, and V refers to the steam flow rate in m/s.
7. The method for calculating the pressure of the injection port of the negative pressure device according to claim 4, wherein the method comprises the following steps: in the step S2, the step S,
gamma is temperature direct reduction rate and psi is potential energy of volumeRho is the density of the injected fluid, and the unit is kg/m3V denotes the flow rate of the injected fluid, which is equal to the nozzle outlet flow rate according to the homogeneous flow theory, and C denotes a constant.
8. The method for calculating the pressure of the injection port of the negative pressure device according to claim 4, wherein the method comprises the following steps: in the step S3, the step S,
q refers to the total amount of fluid flowing out of the injection port, namely the suction volume, and the unit is m3/s，
p denotes the normal pressure in Pa, p2The unit of the pressure of the injected port is Pa.
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| CN113457185A (en) * | 2021-07-06 | 2021-10-01 | 江苏博科华环保科技有限公司 | MVR evaporator capable of adjusting evaporation temperature according to different mother liquor temperature requirements and using method thereof |
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