CN215741894U - Device for producing ammonium sulfate by caprolactam re-drainage liquid and ammonia neutralization crystallization - Google Patents

Abstract

The invention relates to a device for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization, which comprises a DTB neutralization crystallizer, wherein a built-in main condenser is arranged in a DTB neutralization crystallizer body, and a tail condenser and a condensate system are arranged outside the DTB neutralization crystallizer body; the main condenser is matched with a liquid collecting tank, a liquid collecting hopper, a condensate discharging port and a condensate pipeline; the tail condenser is matched with a vacuum facility and a liquid injection system. The built-in main condenser is adopted, so that the pressure drop in the condensation process of the evaporation steam side is eliminated, the evaporation steam amount discharged outside the top of the neutralization crystallizer is greatly reduced, and the pipe diameter and the arrangement difficulty of a vapor phase pipe at the top are reduced; the tail condenser adopts a jet type vacuum condenser, has low pressure drop and low temperature difference, can quickly condense, and does not adopt steam for vacuumizing; the circulating feed liquid of the neutralization crystallizer or the ammonium sulfate mother liquid in the device is used as the replenishing liquid of the injection liquid, so that no waste water is generated during operation, and the device is more environment-friendly; the jet liquid cooler adopts circulating cooling water with large flow and low temperature rise to keep the vacuum degree of the system stable.

Description

Device for producing ammonium sulfate by caprolactam re-drainage liquid and ammonia neutralization crystallization

Technical Field

The invention relates to the technical field of preparing ammonium sulfate by reacting sulfuric acid with ammonia, in particular to a device for producing ammonium sulfate by caprolactam re-drainage liquid and ammonia neutralization crystallization and application thereof.

Background

At present, when most chemical industry production enterprises and partial metallurgy enterprises in China treat byproduct sulfuric acid or ammonia gas, a neutralization crystallization process is usually adopted, a DTB (draft tube baffee) neutralizing crystallizer (draft tube baffee) which is a draft tube and baffle evaporation neutralizing crystallizer is selected, and the draft tube baffee belongs to a typical internal circulation type crystallizer and has high circulation efficiency; introducing the ammonia-containing material flow and the sulfuric acid-containing material flow into a DTB neutralization crystallizer together to synchronously realize neutralization and crystallization processes, and reacting to generate ammonium sulfate crystal slurry containing solid ammonium sulfate particles; a large amount of heat is generated in the neutralization process, so that a large amount of water in the solution is vaporized, and the concentration and crystallization of the ammonium sulfate solution are realized; and discharging the ammonium sulfate crystal slurry at the bottom through a pump after the ammonium sulfate crystal slurry reaches the specified concentration, and then performing thickening, centrifuging and drying to finally obtain an ammonium sulfate crystal product. Guoxinxin et al, recycling treatment of clear mother liquor of ammonium sulfate crystals as a byproduct in MMA production [ J ] the introduction of coal and chemical engineering, 2019, 42(3) introduces the application of a continuous ammonium sulfate DTB neutralization crystallizer to treat waste ammonium sulfate as a byproduct in methyl methacrylate production. Chinese patent CN201411372Y discloses a crystallization device for producing large ammonium sulfate particles by using a solution of ammonium sulfate produced by a coke oven gas purification project in a DTB neutralization crystallizer as a raw material, which improves the internal circulation rate by optimizing internal and external circulation channels of the crystallizer, and controls the growth of crystals by assisting a bottom stirring mode, so that the supersaturation degree of each part in the crystallizer is lower and uniform, and large ammonium sulfate particle products are obtained. Chinese patent CN1757599A, a method for producing ammonium sulfate, discloses the use of neutralization crystallization technology to treat Beckmann heavy liquid waste in caprolactam equipment, separate caprolactam in the heavy liquid waste and produce ammonium sulfate.

Wenjie 'caprolactam ammonium sulfate novel device neutralization reaction crystallization technology' J technical development of enterprises, 2005, 24 (9); ammonium sulfate evaporative crystallization and neutralization crystallization contrast in caprolactam production, Wang, China chemical trade, 2014 (3); the technology and parameters of ammonium sulfate neutralization crystallization process in caprolactam production are described in detail. In the production process of caprolactam, a neutralization crystallization process is mostly adopted in a matched ammonium sulfate device, and the device comprises main equipment such as a DTB (draw texturing yarn) neutralization crystallizer, a decanter, a thickener, a centrifuge, a dryer and the like; the neutralization reaction of the sulfuric acid-containing heavy discharge liquid and ammonia mostly adopts a DTB type neutralization crystallizer with a baffling area; rearranged liquid and gas ammonia respectively enter the guide shell from a nozzle on the annular distributor of the crystallizer through ratio adjustment, an internal circulation channel is formed under the action of the guide shell and a stirrer, an ammonium sulfate solution containing crystal grains is rapidly lifted to a boiling surface on the upper part of the guide shell, water begins to evaporate, slurry flows downwards from the boiling surface along the outer side of the guide shell, the flow rate is reduced in a lower area on the outer side of the guide shell due to the change of the shape of the crystallizer, one part of suspension returns to the guide shell under the action of the stirrer, and the other part of suspension flows upwards to a baffling area; the crystals and the amide oil are settled and separated due to the density difference in the region, and an amide oil layer containing a small amount of ammonium sulfate solution is discharged by an amide oil discharge pump and is conveyed to a decanter for re-layering; part of slurry containing ammonium sulfate crystal grains is pumped out from the middle part of the baffling area by a crystallizer circulating pump, is firstly mixed with part of condensate on an inlet pipeline of the crystallizer circulating pump, is mixed with unsaturated ammonium sulfate mother liquor on an outlet pipeline of the circulating pump, and then returns to the guide shell. When the solid content of the ammonium sulfate in the crystallizer reaches a set value, pumping out ammonium sulfate slurry from the bottom through a crystal slurry discharging pump and conveying the ammonium sulfate slurry into the thickener.

The operation pressure of the DTB neutralization crystallizer is controlled to be about 15KPa (A); the evaporation steam discharged from a vapor phase outlet at the top of the neutralization crystallizer enters a surface condenser, is condensed into condensate by circulating cooling water, automatically flows to a condensate tank and is then pressurized by a condensate pump, a part of condensate is sent into an ammonia gas feeding pipeline to dissolve and absorb ammonia gas, a part of condensate is sent to an inlet pipeline of a circulating pump of the crystallizer to dissolve fine crystals, and a small part of condensate is used for washing each part and finally returns to the crystallizer (101) to balance evaporated water; the uncondensed condensed steam discharged by the surface condenser is pumped out by a steam jet vacuum pump.

The ammonium sulfate neutralization crystallization device has the following characteristics: 1) the process device has large evaporation steam amount and low evaporation steam temperature; 2) the cooling medium is in large demand, and only circulating cooling water can be used as the cooling medium; 3) the pressure drop of the vacuum side (evaporation steam) needs to be strictly controlled in order to ensure the vacuum degree of crystallization evaporation under the limitation of the temperature difference between the circulating cooling water and the heat transfer of the cold and hot sides; 4) the DTB neutralization crystallizer has large specification, large surface condenser area and thick evaporation steam discharge pipeline. Taking a set of ammonium sulfate device which is constructed by matching with a caprolactam device and produces 15 ten thousand tons every year as an example, the evaporation steam amount per hour is about 17 tons, the operation pressure at the top of a DTB neutralization crystallizer is 15-20 kPa (A), the operation temperature of the neutralization crystallizer is 55-65 ℃, and the circulating cooling water consumption is about 1600m³H; the diameter of the neutralization crystallizer is about 6.9 meters; the pipe diameter of an evaporation steam outlet pipeline of the self-neutralization crystallizer is about 1.2 meters; 2 heat exchange areas of 480m are configured²The shell and tube surface condenser.

The ammonium sulfate neutralization crystallization device still has the following optimization potential: 1) the pipe diameter of the evaporation vapor phase discharge pipe at the top of the crystallizer is large, the pipeline cost is high, and the piping difficulty is large; 2) an external and dividing wall type surface condenser is adopted, and the pressure drop of the vacuum side is large; 3) the surface condenser is made of stainless steel, has large equipment specification, occupies a large area and has high comprehensive investment; 4) the steam jet vacuum pump is adopted, so that the steam jet vacuum pump has the advantages of simple structure, reliable work and long service life, but has low efficiency and large steam consumption, and the power steam of the steam jet vacuum pump needs to be condensed by circulating cooling water, so that the energy consumption is increased; 5) after being condensed, the power steam is mixed with the process condensate and then enters the process system, so that the water quantity of the process system is increased, and the sewage treatment and discharge amount is increased.

Chinese patent CN103936032B discloses a method for producing large-particle ammonium sulfate products, which adopts a neutralization crystallization process and equipment to produce large-particle ammonium sulfate by controlling the mass percent of sulfuric acid in a DTB neutralization crystallizer. Chinese patent CN211798914U discloses an ammonium sulfate crystallizer, which realizes more sufficient neutralization reaction and more uniform temperature distribution in a draft tube by adjusting the installation position of a rearrangement nozzle, and reduces the organic liquid drops carried in the water evaporation process. Chinese patent CN111530119A discloses a serial ammonium sulfate crystallization method and device, which adopts two serial crystallizers and a double-effect vacuum crystallization process, fully utilizes the solution heat of gas ammonia and the neutralization heat of sulfuric acid and ammonia, takes first-effect evaporation steam as a heat source, reduces the consumption of circulating cooling water, and improves the proportion of large-particle ammonium sulfate. The existing industrial device and the disclosed technology all adopt an external and tubular surface condenser, all adopt a steam jet vacuum pump, and do not relate to the optimization and improvement of a condensation mode and a vacuum facility.

In the vacuum condensation process, the vacuum side pressure drop factor is an important factor, and influences the design, condensation effect, vacuum degree and suction capacity of the vacuum condenser; the flow, equipment and pipelines with low pressure drop are selected, so that the condensation of the evaporation steam is facilitated, and the vacuum power consumption is reduced.

The direct contact condenser has the characteristics of large processing capacity, small pressure drop, small required heat transfer temperature difference, large two-phase contact area and high heat transfer efficiency, is suitable for occasions where two fluids are allowed to be mixed in the process, and is commonly used for cooling gas or condensing water vapor; the main types of the direct contact condenser are a liquid column condenser, a liquid film condenser, a filling tower type condenser and a jet type condenser 4, wherein 1-3 types of the direct contact condenser are that condensed vapor phase and cooling medium flow in a countercurrent way in the condenser, the jet type condenser belongs to parallel flow condensation, the vapor phase and the cooling medium sprayed out from a nozzle are directly mixed and condensed, entrained non-condensable gas flows out from a lower discharge pipe, the pressure drop in the vapor phase condensation process is extremely small, and the direct contact condenser is more suitable for vacuum occasions; the design and application of water jet condenser in Kangchuan river [ J ] chemical design, 2001, 11(3) introduces it in more detail.

The liquid jet vacuum pump is used in chemical industry, and its principle and structure are basically the same as that of steam jet vacuum pump, and is formed from three main portions of nozzle, suction chamber and diffuser, and is characterized by that it utilizes the mutual conversion and transfer of energy produced by fluid flow to implement suction, and the working fluid with a certain pressure can be jetted from a group of nozzles at high speed, and projected into the throat pipe in the form of cone, and its static pressure energy can be converted into kinetic energy, and at the outlet of nozzle the partial vacuum can be produced, and the sucked fluid can be jetted into suction chamber from equipment, and then mixed with working fluid and taken away by high-speed jet flow, and the kinetic energy of mixed fluid can be converted into pressure energy by the action of diffuser, and the gas-liquid mixture can be discharged from outlet of jet pump. And the gas-liquid mixture is delivered to a gas-liquid separator, non-condensable gas is separated, the working liquid is pressurized by a pump and then delivered to a cooler, and the working liquid is cooled to the required temperature and returned to a nozzle of a liquid jet pump. The liquid jet vacuum pump is suitable for sucking media containing condensable gas, dust and particles, is suitable for occasions where working liquid and a process system are compatible, and has more advantages in occasions where water is used as the working liquid. Compared with a steam jet vacuum pump, the liquid jet vacuum pump has the following advantages: 1) the water vapor is not used as power, the efficiency is relatively high, and the energy consumption is low; 2) a large-area condenser is not needed, and the installation is simple and convenient; 3) no additional waste water is produced; 4) the vacuum degree is convenient to adjust; 5) the noise is small.

A complete jet condenser is required to be matched with a jet liquid tank, a jet liquid pump, a jet liquid cooler, instruments, pipelines and the like; the complete liquid jet vacuum pump comprises a liquid tank, a jet liquid pump, a jet liquid cooler, an instrument, a pipeline and the like which need to be matched; the matched equipment of the two is the same, but the related process parameters are different.

The common jet condenser has large quantity of cooling medium required by unit vapor phase condensation; for a liquid jet vacuum pump, when the amount of the extracted gas is large and the vacuum degree is high, a large amount of liquid jet is needed, and particularly, in the case of large condensed steam content, the needed amount of liquid jet is larger; based on the differences of vacuum degree, steam evaporation amount and cooling medium, the prior art cannot be simply applied to the prior ammonium sulfate neutralization and crystallization device.

In the process of researching heat exchange and vacuum technology, the inventor finds that the spray atomization type condenser adopted in the sugar industry has better advantages when being applied under specific conditions. The 'New equipment of theoretical vacuum condensing system-spray atomization condenser' of Chiense et al [ J ], Guangxi light industry, 2007, 23(3) have described the spray atomization condenser in detail in sugar industry; chinese patent CN201040758Y discloses a crystallizer vacuum condenser belonging to the technical field of sugar-making vacuum equipment, which comprises a water inlet pipe, a water collecting chamber, a shell, a taper pipe and a tail pipe, wherein the water collecting chamber is divided into a condensation section and a suction section, the condensation section and the suction section of the juice steam (evaporation steam) are designed in a condenser, the condensation section condenses the juice steam with atomized water, and the suction section sucks non-condensable gas with high-speed jet water. Chinese patent CN107699640A discloses a water-cooled high-efficiency vacuum condenser system belonging to the technical field of sugar-making vacuum process, which comprises a juice steam generating tank, a pipeline, a water filtering device, a vacuum condensing device, a water collecting pool, a circulating water pool and a water suction pump which are connected together through the pipeline; the form of combining a plurality of atomizing nozzles and spray nozzles is adopted, so that the vacuum degree is effectively improved, and the water consumption is saved. The vacuum condensers adopted by the two patents are similar in structure, belong to direct contact condensers, organically combine a jet condenser with a hydraulic jet vacuum pump, and are provided with a spray nozzle and a jet nozzle in an equipment cavity, wherein the spray nozzle is used for fully and quickly mixing and transferring heat with juice steam by spraying atomized water drops with large surface area, so that the water steam is quickly condensed into water to form vacuum; the rest non-condensable gas is pumped by the jet water ejected by the jet nozzle and is discharged out of the tail pipe, so that the aim of stabilizing high vacuum is fulfilled.

In the sugar industry, juice steam (evaporation steam) generated in the processes of boiling sugar in vacuum and crystallizing sugar making is large, the condensation load of a vacuum condenser is large, the required cooling water quantity is also large, natural water such as river water is mostly adopted as cooling water, and the use characteristics that the inlet water temperature is low, the outlet water temperature is not limited, and the water is discharged after being used once exist; the technology has the characteristics of stable vacuum degree, relative energy saving and the like; however, the amount of cooling water and the amount of sprayed water in the technology are too large, and disposable water is not suitable for the production requirement of large-scale chemical devices and is not in accordance with the development concept of environmental protection.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and the inventor analyzes the characteristics and requirements of a DTB (draw texturing yarn) neutralization crystallization process and equipment for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization, researches the technologies of a liquid jet vacuum pump, a jet condenser, a jet atomization condenser and the like, creatively provides a device for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization with low pressure drop, low energy consumption, more environmental protection and less investment by combining and improving a spray condensation vacuum technology and an ammonium sulfate DTB neutralization crystallizer process technology, and is applied to the production of ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization.

A device for producing ammonium sulfate by caprolactam re-drainage liquid and ammonia neutralization crystallization comprises a DTB neutralization crystallizer; a main condenser is arranged in the DTB neutralization crystallizer body, and a tail condenser, a condensate system and other related equipment are arranged outside the crystallizer body to form a neutralization crystallization process and a device; the main condenser is also matched with a liquid collecting tank, a liquid collecting bucket, a condensate discharging port and a condensate pipeline; the tail condenser is also matched with a vacuum facility and a liquid injection system; the tail condenser is preferably a jet condenser; the liquid collecting tank collects the condensate generated on the shell side of the main condenser, the condensate is discharged through a condensate outlet on the DTB neutralization crystallizer cylinder and automatically flows to a condensate system; a vapor phase outlet at the top of the DTB neutralization crystallizer is communicated to a jet condenser, a small amount of evaporation vapor containing non-condensable gas is condensed in the jet condenser, the non-condensable gas is sucked by a liquid jet vacuum pump to form vacuum, jet liquid containing the non-condensable gas and the condensed liquid is discharged into a jet liquid tank of a jet liquid system from a liquid discharge port at the bottom of the jet condenser, then is pressurized by a jet liquid pump and is cooled by a jet liquid cooler, and is circulated to a jet liquid inlet of a nozzle, so that the cyclic utilization of the jet liquid is realized, and the discharged jet liquid automatically flows to the condensed liquid system; a spraying facility is arranged above the main condenser and below the liquid collecting tank; the circulating feed liquid of the neutralizing crystallizer is used as a supplement liquid of the injection liquid, and the balanced injection liquid automatically flows to a condensate system; the spray liquid cooler is cooled by circulating cooling water.

The liquid collecting tank collects the condensate generated by the main condenser, the condensate passes through the liquid collecting hopper and the condensate outlet and automatically flows to a condensate system, and the condensate direction is the same as that of the prior art; and discharging the remaining small amount of evaporation steam and non-condensable gas from a vapor phase outlet at the top of the DTB neutralization crystallizer to a tail condenser. The non-condensed evaporation steam and the non-condensable gas are condensed in a tail condenser by a spray condenser taking the injection liquid as a cooling medium, then the spray condenser takes the injection liquid as a liquid injection pump of a power medium to suck and form vacuum, the non-condensable gas and the condensed liquid are discharged to an injection liquid system from an outlet at the bottom of the tail condenser, the liquid is pressurized to an injection liquid cooler through an injection liquid pump, the liquid is cooled to a specified temperature by circulating cooling water and is sent to an injection liquid inlet of the injection condenser, the cyclic utilization of the injection liquid is realized, the balanced injection liquid is discharged to the condensed liquid system, and the steam is not adopted in the vacuum pumping.

The DTB neutralization crystallizer has the characteristics of large cylinder diameter and high internal space, a built-in main condenser is arranged in the upper space of a DTB neutralization crystallizer body and forms integrated equipment with the neutralization crystallizer, and the condenser extends into a heat exchange part in the neutralization crystallizer and is not provided with a shell, so that most of evaporation steam is condensed at a partition wall under the condition of no pressure drop, and the pressure drop of the evaporation steam (vacuum) side is reduced; more than 95% of the evaporation steam generated by the neutralization reaction in the crystallizer is condensed into liquid by the main condenser, so that the evaporation steam quantity discharged from a vapor port at the top of the DTB neutralization crystallizer is greatly reduced, and the pipe diameter of a vapor phase pipe from the top of the DTB neutralization crystallizer to the tail condenser and the condensation cooling load of a downstream tail condenser are reduced.

The main condenser is one or a combination of a shell-and-tube condenser and a plate-shell condenser, and consists of 1 or more than one condenser. The evaporation steam generated by the neutralization crystallization can enter the heat exchange part of the main condenser from multiple directions and is not influenced by the baffle plate, the tube bundle (or the shell plate) and the gap of the cylinder, and the pressure drop in the condensation process can be ignored; the main component of the evaporation steam is water, and the coefficient of a heat transfer film on the condensation side of the water vapor is usually very large and is larger than the coefficient of a similar heat transfer film on the tube side; the cooling medium of the main condenser is circulating cooling water, and the pipe side (plate side) and the evaporation steam form cross flow to take away heat released by the evaporation steam; the condenser is not provided with a shell and a baffle plate, has small influence on the total heat transfer coefficient of the condenser, and can still keep the condenser to have higher total heat transfer coefficient; when the vacuum degree of water vapor condensation is close to 10kPa (a), the low pressure drop can obviously increase the water vapor condensation temperature, thereby increasing the logarithmic mean temperature difference of heat exchange and being beneficial to the condensation.

The heat exchange part of the main condenser is arranged in vapor phase space at the middle part of the DTB and the upper part of the crystallizer, and the heat exchange section of the main condenser in the DTB and the crystallizer is not provided with a shell. Based on the consideration of installation, internal space and effective heat transfer, the diameter of a shell of a single condenser is not more than phi 1500, preferably not more than phi 1200, and in order to meet the heat exchange requirement, the specification and the number of the built-in condensers are comprehensively determined by combining the space which can be arranged at the top of the DTB neutralization crystallizer according to the conventional engineering calculation; the invention does not require the installation heights of all condensers to be consistent, thereby being beneficial to reducing the pressure drop of the evaporation steam side, the effective heat transfer of the condensers and the arrangement of the condensers; on the premise of not increasing the diameter of the crystallizer, the cylinder body of the DTB neutralization crystallizer can be properly heightened according to engineering knowledge and design rules to increase the height of a top vapor phase space, so that a certain distance is kept between each main condenser and an operating liquid level above a guide cylinder of the crystallizer.

The vapor phase space at the upper part of the DTB neutralization crystallizer is provided with a mounting hole corresponding to the cylinder wall, the mounting hole is welded with a short pipe with the same diameter as the shell of the main condenser towards the outside of the cylinder, and the length of the short pipe is used for meeting the requirement of the condenser; the outlet end of the short pipe is provided with a flange, and the main condenser, a main condenser pipe box and the short pipe are connected and combined by the flange to realize the connection and fixation of the DTB neutralization crystallizer cylinder and the condenser pipe box end; the pipe box is provided with a cooling water inlet and a cooling water outlet which are respectively connected with an external corresponding cooling water upper water and a water return pipe; the arrangement of the channel box, the internal pass partition plate and the cooling water inlet and outlet is designed according to the common engineering practice.

The main condenser is fixed, supported or suspended in the DTB and the crystallizer through bolts or/and welding with parts such as steel beams, rod pieces and the like which are arranged in the DTB and the crystallizer. The heat exchange part of the main condenser is almost completely positioned in the neutralization crystallizer, the self-loading gravity center of the main condenser is also positioned in the neutralization crystallizer, and corresponding supporting beams, rods, and other parts are required to be arranged in the DTB neutralization crystallizer, so that the heat exchange part not only is used for supporting various loads of the main condenser, but also plays a role in fixing or limiting the displacement of the condenser and the like, and is convenient for the installation and maintenance of the main condenser; the arrangement position, the number and the specification of the supporting beams are related to the specification, the number and the arrangement of the main condenser, and the design is carried out according to the conventional engineering technology.

The liquid collecting tank is arranged right below the heat exchange component of the main condenser, and the liquid collecting area of the liquid collecting tank is not smaller than the projection area of the main condenser from the right above; the liquid collecting groove can be in a groove form, and can also be a circular arc-shaped plate with a baffle; the condensate outlet end of the liquid collecting tank is tightly connected with the inner side of the crystallizer cylinder, and the slope is towards the condensate outlet end and ranges from 1 degree to 10 degrees. The evaporation steam generated by the neutralization heat in the DTB and the crystallizer rises to the periphery of the main condenser, exchanges heat with circulating cooling water, releases latent heat, condenses into liquid, and the condensate drips to the liquid collecting tank below under the action of gravity.

The condensed liquid outlet end of the liquid collecting tank is tightly connected with the inner side of the crystallizer cylinder, and a gap or a gap for liquid leakage does not exist between the connecting parts; in addition to the provision of the liquid collection tank according to the invention, the liquid collection tank is technically required to maintain a directional downward slope toward the condensate outlet end; the condensate in the liquid collecting tank should not overflow or leak to the DTB neutralization crystallizer evaporation surface; the horizontal slope angle of the sump is related to the amount of condensate and the sump specification, which are common engineering technical knowledge and can be calculated and designed through conventional engineering.

The liquid collecting hopper is arranged on the inner side of the part where the discharge end of the liquid collecting tank is connected with the cylinder of the DBT crystallizer, the liquid collecting hopper, the discharge end of the liquid collecting tank and the cylinder of the crystallizer are tightly connected, and the liquid collecting hopper is tightly connected with the end plate of the discharge end of the liquid collecting tank through a similar connecting groove or a similar connecting plate; the function of the liquid collecting hopper is the same as that of the distillation tower, the depth and the volume of the liquid collecting hopper, the connection mode of the liquid collecting hopper, the cylinder and the pipe orifice are the same as those of the liquid collecting hopper of the distillation tower, and the design is carried out according to the conventional engineering knowledge, so that the condensate does not overflow or leak back to the crystallizer.

The condensate discharging port is an orifice formed in the wall of the joint of the liquid collecting hopper and the crystallizer cylinder, and the bottom of the condensate discharging port is not higher than the bottom of the liquid collecting hopper, so that the discharge and the clean discharge are facilitated. The condensate discharging port, the collecting hopper, the main condenser and the collecting tank are in one-to-one correspondence, so that condensate collected by the collecting tank can be guaranteed to smoothly flow to the collecting hopper from the collecting tank, then be smoothly discharged from the condensate discharging port, and finally automatically flow to a condensate system matched with the crystallization device through an external pipeline; the liquid collecting tank collects the condensate generated on the shell side of the main condenser, the condensate in the liquid collecting tank flows to the liquid collecting hopper and then automatically flows to a condensate system through a condensate discharge port and an external pipeline; the specifications of the liquid collecting tank, the liquid collecting hopper and the condensate discharging port can be calculated according to conventional engineering knowledge, and the connection mode, the mechanical strength and the like among the three can be designed according to general machinery.

The DTB neutralization crystallizer is operated in vacuum, the setting of a condensate system and the design of a pipeline ensure that condensate has enough potential difference to ensure smooth self-flow, and a liquid seal function is provided to prevent external gas from entering the DTB neutralization crystallizer, which is the conventional requirement and method of engineering design.

The spraying facility is arranged above the main condenser and below the liquid collecting tank, and is characterized in that one or more groups of spraying nozzles are arranged above the main condenser, one or more groups of spraying nozzles are arranged below the liquid collecting tank, and the horizontal projection areas of respective washed equipment are covered; the spraying liquid comes from a condensate system in the neutralization crystallizer device, the main component of the condensate is water and almost does not contain ammonium sulfate, and the condensate is used as a medium to wash and dissolve so as to remove ammonium sulfate crystals possibly adhered to parts; the number and arrangement of the spray nozzles and the amount of the required condensate can be calculated and arranged according to a method provided by an engineering professional manual.

The tail condenser is externally arranged in the neutralization crystallizer, can adopt a direct contact condenser, also can adopt a dividing wall type condenser, preferably selects the direct contact condenser, and the direct contact condenser has the characteristics of good condensation effect, small heat transfer temperature difference, small pressure drop in the condensation process and the like; the disclosed technology adopts a dividing wall type surface condenser, cooling water condenses evaporation steam in an indirect mode at the cold side of the heat exchanger, the dividing wall type condenser can be one or a combination of a tube type heat exchanger, a spiral plate type heat exchanger and a plate type heat exchanger, and most of the prior art is the tube type heat exchanger; the direct contact condenser is in the following types: the liquid column type condenser, the liquid film type condenser, the filling tower type condenser and the jet type condenser are selected, the jet type condenser is selected preferably, the pressure drop in the condensation process is extremely small, the contact area between fluids is large, and the condensation effect is good.

The spray type condenser is characterized in that a nozzle is arranged in the upper space in the cavity of the condenser body, the shell is provided with a vapor phase inlet and a spray liquid inlet, and a liquid outlet is formed in the bottom of the condenser and is vertically arranged; the nozzle comprises a conventional nozzle and an atomizing nozzle, and is preferably an atomizing nozzle; a small amount of uncondensed evaporation steam and non-condensable gas in the DTB neutralization crystallizer are discharged to a tail condenser vapor phase inlet from a top vapor phase outlet of the DTB neutralization crystallizer and are directly contacted with spray liquid which is distributed to an atomizing nozzle from a spray liquid cavity and is atomized after passing through the atomizing nozzle, low pressure drop and rapid condensation and cooling are realized, and the condensate and the spray liquid fall into a liquid collecting pipe at the lower part of the jet condenser under the action of gravity.

The vacuum facility is used for sucking the non-condensable gas condensed by the tail condenser to form the required vacuum degree, and the vacuum facility can select one or the combination of a liquid jet vacuum pump, a liquid ring vacuum pump and a Roots vacuum pump, preferably selects the liquid jet vacuum pump; the technology of the invention is optimized and improved, the existing process liquid in the device is used as the liquid medium of the injection liquid of the injection vacuum pump, the vacuum degree of the system is favorably stabilized, the waste water discharge is favorably reduced, and the steam injection vacuum pump is not used, so that the energy is saved.

The jet condenser and the liquid jet vacuum pump can be arranged independently, or the liquid jet vacuum pump is embedded into the barrel of the jet condenser, which is called as the jet vacuum condenser; the independent arrangement is adopted, and the non-condensable gas discharged by the jet condenser is discharged to a liquid jet vacuum pump through an external pipeline; the preferred injection type vacuum condenser, the gas after the injection condensation is sprayed and sucked by the liquid immediately, have the characteristics of compact equipment, small pressure drop in the condensation and vacuum-pumping processes, and the like.

The jet type vacuum condenser is characterized in that an atomizing nozzle for condensing and cooling and a jet nozzle for vacuumizing are arranged at the upper part in a barrel body of the jet tail condenser from top to bottom, a diffusion pipe and a liquid collecting pipe are sequentially arranged at the part below the barrel body, and a liquid discharging port is arranged at the bottom; the atomization nozzle and the injection nozzle are respectively provided with an injection liquid inlet and an injection liquid cavity in the condenser shell and are connected with the outlet end of an injection liquid cooler of an injection liquid system through a pipeline; the spray nozzle is vertically installed, spray liquid is vertically sprayed downwards at a high speed through the spray nozzle, the non-condensable gas after being atomized, condensed and cooled is sucked to form vacuum, and the spray liquid containing the non-condensable gas and the condensed liquid is discharged to a spray liquid tank of a spray liquid system from a liquid discharge port at the bottom through a diffusion pipe and a liquid collection pipe of a spray vacuum tail condenser. For given process conditions such as condensing load, vacuum degree, cooling medium conditions and the like, according to formulas and data described in the existing published technical data, the jet vacuum condenser is designed, and the design comprises the steps of determining the specification of the jet vacuum condenser, the size of each part of the jet vacuum condenser and the specification, the number and the distribution of the spray nozzles and the jet nozzles, so that the designed result can achieve the condensing effect and meet the requirement of the vacuum degree of the system.

The injection system comprises an injection liquid tank, an injection liquid pump, an injection liquid cooler and the like; the injection liquid tank is provided with an injection liquid return port, an injection liquid outlet, an overflow port and a liquid supplementing port, and the top of the injection liquid tank is provided with an exhaust port; the injection liquid and the condensate carry a small amount of non-condensable gas, the non-condensable gas flows into an injection liquid tank from a liquid discharge port at the bottom of the injection vacuum tail condenser under the action of gravity, gas-liquid separation is carried out in the injection liquid tank, wherein the non-condensable gas is discharged from an exhaust port of the injection liquid tank through a high-point discharge pipe, and the injection liquid flows from an injection liquid outlet of the injection liquid tank to an inlet of an injection liquid pump; the spray liquid is pressurized by a spray liquid pump, and is cooled to a specified temperature by circulating cooling water in a spray liquid cooler, and then is circulated to an atomizing nozzle of a spray vacuum tail condenser and a corresponding inlet of the spray nozzle, so that the spray liquid is recycled; the condensate generated in the condensation process and the supplemented circulating slurry increase the injection liquid of the system, and the surplus injection liquid is discharged to the condensate system through an overflow port of the injection liquid tank and a corresponding pipeline, so that the balance of the working liquid of the injection liquid system is realized.

The condensed atomizing nozzle and the vacuumized spraying nozzle share one set of spraying liquid system.

The application of the device for producing ammonium sulfate by caprolactam reliquefaction liquid and ammonia neutralization crystallization in the process of producing ammonium sulfate by caprolactam reliquefaction liquid and ammonia neutralization crystallization is as follows:

the ammonia gas and the rearrangement liquid enter a DTB neutralization crystallizer through respective nozzles, the operating pressure of the neutralization crystallizer is 10-25kPa (a), and the operating temperature is about 40-60 ℃. 90-95% of the evaporated steam generated by neutralizing the crystallization heat is condensed at the shell side of the main condenser, the condensate is collected by a liquid collecting tank below the main condenser, flows into a liquid collecting hopper and a condensate discharging port to be discharged out of the crystallizer and then automatically flows to a condensate system, and the condensate direction is the same as that of the disclosed technical process.

Evaporating steam and non-condensable gas which are not condensed by a main condenser in the DTB neutralizing crystallizer are discharged to a vapor phase inlet of a tail condenser from a vapor phase outlet at the top of the DTB neutralizing crystallizer, the evaporated steam and the non-condensable gas are directly contacted with atomized spray liquid and condensed in the tail condenser (a jet type vacuum condenser), components such as the non-condensable gas and the like are jetted and sucked by the liquid to form vacuum, and all fluids pass through a diffusion pipe and a liquid collecting pipe of the jet vacuum tail condenser and are finally discharged into a spray liquid tank of a spray liquid system from a liquid discharge port at the bottom of the jet vacuum tail condenser; carrying out gas-liquid separation on the injection liquid in the injection liquid tank, discharging non-condensable gas from an exhaust port of the injection liquid tank through a high-point discharge pipe, and enabling the injection liquid to flow from an injection liquid outlet of the injection liquid tank to an inlet of an injection liquid pump; the spray liquid is pressurized by a spray liquid pump, and is cooled to a specified temperature by circulating cooling water in a spray liquid cooler, and then is circulated to an atomizing nozzle of a spray vacuum tail condenser and a corresponding inlet of the spray nozzle, so that the spray liquid is recycled; tapping a pipeline from an outlet pipe of a circulating pump of the crystallizer to a liquid supplementing port of a spraying liquid tank, and supplementing circulating liquid into a spraying liquid system; and the injection liquid after the balance of the injection liquid system is discharged to a condensate system through an overflow port of the injection liquid tank and a corresponding pipeline and returns to the crystallizer.

The spraying liquid is formed by mixing one or two of circulating feed liquid and ammonium sulfate mother liquid of a DTB neutralization crystallizer and condensate of a tail condenser, and does not contain ammonium sulfate crystals; the condensate is generated by condensation of the evaporation steam in the operation process of the jet vacuum condenser; the circulating feed liquid refers to slurry containing ammonium sulfate and extracted from the middle part of a baffling area of the crystallizer by a crystallizer circulating pump, and is from a tapping pipeline on an outlet pipe of the crystallizer circulating pump to a liquid supplementing pipe of a spraying liquid tank; the ammonium sulfate mother liquor is generated in the centrifugal process of an ammonium sulfate device, is sent to an inlet pipeline of a circulating pump of the crystallizer through a mother liquor pump and finally enters the neutralization crystallizer, and when the ammonium sulfate mother liquor is used as a spraying liquor, the ammonium sulfate mother liquor is added with the circulating feed liquor to the spraying liquor tank from a tapping pipeline of an outlet pipe of the mother liquor pump to a liquor replenishing pipe of the spraying liquor tank; the maximum adding amount of the circulating feed liquid is used for ensuring that the spraying liquid is in an unsaturated state and does not contain crystals, and the adding amount of the circulating feed liquid is controlled not to exceed the amount of the condensate generated by the tail condenser; the minimum addition of the circulating feed liquid ensures that the pH value of the spray liquid entering the tail condenser is less than 7.

The spray liquid cooler is characterized in that a dividing wall type cooler is adopted, and the spray liquid cooler is one or a combination of a shell and tube heat exchanger, a spiral plate heat exchanger and a plate heat exchanger, and preferably selects the plate heat exchanger. The plate heat exchanger can provide smaller heat transfer temperature difference and is particularly suitable for liquid-liquid heat exchange occasions to obtain higher heat exchange efficiency and lower outlet temperature of the injection liquid.

The spray liquid cooler is characterized in that the cooling medium adopts circulating cooling water; the circulating cooling water is part or all of the circulating cooling water used by the main condenser, is firstly used as a cooling medium of the spray liquid cooler, is subjected to heat exchange through the spray liquid cooler and then is conveyed to a cooling water inlet of the main condenser, and the inlet-outlet temperature difference of the cooling water passing through the spray liquid cooler is controlled to be not more than 1 ℃; the cooling medium adopts large flow and low temperature rise, so that the jet liquid cooler obtains the maximum logarithmic mean temperature difference on the premise of not using low-temperature cooling water to reduce the outlet temperature of the jet liquid, wherein the temperature is the inlet temperature of the tail condenser.

According to the method for producing ammonium sulfate by neutralizing and crystallizing caprolactam re-drainage liquid and ammonia, the temperature of a spray liquid at an inlet of a tail condenser is not more than 45 ℃, and preferably 35-40 ℃. The temperature is reached after the spray liquid is cooled by the spray liquid cooler.

According to the method for producing ammonium sulfate by caprolactam re-drainage liquid and ammonia neutralization crystallization, the temperature of a circulating jet liquid discharged from the bottom of a tail condenser is not more than 55 ℃, and preferably 40-50 ℃; the temperature of the discharged circulating spray liquid should not exceed the maximum temperature allowed by vacuum pumping, and the maximum temperature theoretical value is the saturation temperature of the spray liquid under the corresponding vacuum degree.

The inlet temperature of the injection liquid to the tail condenser and the temperature of the injection liquid discharged from the tail condenser are related to the vacuum degree, the condensation load, the vacuum load, the injection liquid amount, the external cooling medium and the like required by the process; aiming at given process conditions including vapor phase quantity and non-condensable gas quantity entering a jet vacuum condenser and vacuum degree of a neutralization crystallizer, the inlet temperature and the discharge temperature of jet liquid are set firstly, the condensed jet liquid quantity and the vacuumizing jet liquid quantity are calculated according to public technical information, the minimum working pressure of a nozzle inlet is calculated according to the minimum working pressure, and an optimized value is found among the inlet-outlet temperature difference, the flow and the pressure of the jet liquid. And adjusting facilities are arranged on the condensation spraying liquid inlet pipe and the vacuumizing spraying inlet pipe, so that spraying liquid of two nozzles in the vacuum tail condenser meets the requirement. The above work is conventional engineering calculations, and industry engineers can design the vacuum tail condenser including the nozzle, and related equipment, process flows, instruments, pipelines, etc. according to design manuals or data.

The beneficial effects of the technology of the invention are:

1. the built-in main condenser is adopted, a shell extending into a heat exchange section of the condenser in the crystallizer is omitted, evaporation steam of the crystallizer can directly enter between condenser tube bundles (or plates) in multiple directions to be condensed by circulating cooling water, and does not pass through a pipeline, an inlet pipe, an outlet pipe and a baffle plate, so that the pressure drop in the condensation process at the evaporation steam side is eliminated, the vacuumizing load is reduced, and heat transfer and full condensation of the evaporation steam are facilitated.

2. After most of the evaporation steam is condensed in the main condenser, the amount of the evaporation steam discharged from the top of the neutralization crystallizer is greatly reduced, the pipe diameter of a vapor phase pipe of the DTB neutralization crystallizer is greatly reduced, and the design difficulty and investment of the pipeline are reduced.

3. The tail condenser adopts a jet condenser, and the cooling medium is sprayed to form a mist to be in direct contact with the evaporation steam, so that high-efficiency heat transfer is realized, and the effects of low heat transfer temperature difference, low pressure drop and quick condensation are realized.

4. The spray type vacuum condenser integrating spray condensation and liquid spray vacuumizing is adopted, so that condensation and vacuum facility equipment is simplified, the flow resistance of non-condensable gas between the two equipment is eliminated, and the pressure drop of a system and the vacuum degree and energy consumption required by a vacuum pump are further reduced.

5. And liquid is sprayed for vacuumizing, and steam is not used as a power medium, so that the energy consumption is reduced.

6. The circulating feed liquid of the neutralization crystallizer is used as the injection liquid supplementing liquid, so that external water supplementing and external water draining are not needed during operation, and the system is more environment-friendly; meanwhile, as the circulating feed liquid of the crystallizer is ammonium sulfate solution, the vacuum degree of the vacuum system can be improved again.

7. The jet liquid cooler adopts circulating cooling water with large flow and low temperature rise, the operation vacuum degree is more stable, and the system vacuum degree can be kept stable while low-temperature cooling water is not needed.

Drawings

FIG. 1 is a schematic diagram of a DTB neutralization crystallizer system of the present technology.

In fig. 1, the neutralization crystallization system 100 mainly comprises: the device comprises a DTB neutralization crystallizer 101, a neutralization crystallizer cylinder 102, a guide flow cylinder 103, a separation cylinder 104, a baffling area 105, a washing facility 106, a defoaming facility 107, a stirrer 108, a crystallizer circulating pump 110, a crystal slurry discharging pump 111, an amide oil discharging pump 112, an evaporation steam pipe 115, an ammonium sulfate mother liquor pipe 116, a circulating feed liquor pipe 117, a main condenser 151, a liquid collecting tank 152, a liquid collecting hopper 153, a condensate outlet 154 and a condensate pipe 155.

FIG. 2 is one of the process flow diagrams of the DTB neutralization crystallizer apparatus of the present invention.

In the attached fig. 2, the process flow consists of a neutralization and crystallization system 100, a spraying vacuum tail condensation system 200, a condensate system 300 and a spraying liquid system 400, wherein:

the neutralization crystallization system 100 mainly includes: the equipment comprises a DTB neutralization crystallizer 101, a neutralization crystallizer cylinder 102, a guide flow cylinder 103, a separation cylinder 104, a baffling area 105, a washing facility 106, a defoaming facility 107, a stirrer 108, a crystallizer circulating pump 110, a crystal slurry discharge pump 111, an amide oil discharge pump 112, an evaporation steam pipe 115, an ammonium sulfate mother liquor pipe 116, a circulating feed liquor pipe 117, an ammonium sulfate mother liquor branch pipe 118, a circulating feed liquor branch pipe 119, a main condenser 151, a liquid collecting tank 152, a liquid collecting hopper 153, a condensate outlet 154 and a condensate pipe 155.

The ejector vacuum tail condenser system 200 essentially comprises: a jet vacuum tail condenser 210, a jet vacuum tail condenser cylinder 211, an atomizing nozzle 212, a jet nozzle 213, a diffusion tube 214, a liquid collecting tube 215, a vapor phase inlet 216, an atomizing jet liquid cavity 217, a vacuumizing jet liquid cavity 218, an atomizing jet liquid tube 220, a vacuumizing jet liquid tube 221 and a liquid discharging tube 222.

The condensate system 300 generally includes: a condensate tank 301, a condensate pump 302 and a condensate return pipe 303.

The spray system 400 basically includes: the system comprises a spray liquid tank 401, a spray liquid pump 402, a spray liquid cooler 403, an overflow pipe 404, a noncondensable gas discharge pipe 405, a spray liquid pipe 406, a liquid supplementing pipe 407, a cooling water feeding pipe 408, a cooling water bypass 409 and a cooling water pipe 410.

FIG. 3 shows a second process flow diagram of the DTB neutralization crystallizer apparatus of the present invention.

In fig. 3, the process flow consists of a neutralization and crystallization system 100, a spray tail condensation system 200, a condensate system 300, a spray liquid system 400, and a liquid ring vacuum system 500, wherein:

the crystallization system 100 essentially comprises: the device comprises a DTB neutralization crystallizer 101, a neutralization crystallizer cylinder 102, a guide flow cylinder 103, a separation cylinder 104, a baffling area 105, a washing facility 106, a defoaming facility 107, a stirrer 108, a crystallizer circulating pump 110, a crystal slurry discharging pump 111, an amide oil discharging pump 112, an evaporation steam pipe 115, an ammonium sulfate mother liquid pipe 116, a circulating liquid pipe 117, an ammonium sulfate mother liquid branch pipe 118, a circulating liquid branch pipe 119, a built-in main condenser 151, a liquid collecting tank 152, a liquid collecting hopper 153, a condensate outlet 154 and a condensate pipe 155.

The spray tail condensation system 200 mainly includes: a spray tail condenser 210, a spray tail condenser cylinder 211, an atomizing nozzle 212, an atomizing spray liquid cavity 217, a vacuum air pipe 219, an atomizing spray liquid pipe 220 and a liquid discharge pipe 222.

The condensate system 300 generally includes: a condensate tank 301, a condensate pump 302 and a condensate return pipe 303.

The spray system 400 basically includes: a spray liquid tank 401, a spray liquid pump 402, a spray liquid cooler 403, an overflow pipe 404, a spray liquid pipe 406, a liquid supplementing pipe 407, a cooling water supply pipe 408, a cooling water bypass 409, a cooling water pipe 410,

the liquid ring vacuum system 500 mainly includes: a liquid ring vacuum pump 501, a gas-liquid separation tank 502, a working fluid cooler 503, a working fluid replenishing pipe 504, a noncondensable gas discharge pipe 505 and a working fluid discharge pipe 506.

FIG. 4 is a schematic diagram of a prior art DTB neutralization crystallizer apparatus process flow.

In fig. 4, the process flow consists of a neutralization and crystallization system 100, a vacuum condensation system 200 and a condensate system 300, wherein:

the neutralization crystallization system 100 mainly includes: the device comprises a DTB neutralization crystallizer 101, a neutralization crystallizer cylinder 102, a guide shell 103, a separation shell 104, a baffling area 105, a washing facility 106, a defoaming facility 107, a stirrer 108, a crystallizer circulating pump 110, a crystal slurry discharge pump 111, an amide oil discharge pump 112, an evaporation steam pipe 115, an ammonium sulfate mother liquor pipe 116 and a circulating feed liquor pipe 117.

The vacuum condensation system 200 basically comprises: the system comprises a condenser 201, a primary steam jet pump 202, a primary jet condenser 203, a secondary steam jet pump 204, a secondary jet condenser 205, a condensate discharge pipe 206, a condensate discharge pipe 207, a non-condensate pipe 208 and a non-condensate gas discharge pipe 209.

The above figures have the meaning of Chinese and English code, SML-medium pressure steam, pressure of 0.9Mpa, and superheat no less than 5 deg.C; CWS-recirculated cooling water (water), water temperature 33 ℃; CWR-circulating cooling water (backwater), the backwater temperature is 40 ℃; RWS-Low Cooling Water (Water supply), Water supply temperature 7 ℃; RWR-low temperature cooling water (backwater), the backwater temperature is 12 ℃.

The devices in the above figures are meant to include the technical devices of the present invention and their closely related process steps, such as: decanting, thickening, centrifuging and drying to obtain solid ammonium sulfate.

In the above figures, the term "outside" refers to materials, equipment, etc. not included in the above apparatus.

Detailed Description

The present technology will be further described with reference to the accompanying drawings, but the scope of the present invention is not limited thereto.

Example 1:

the caprolactam re-drainage liquid and the ammonia neutralization crystallization device have the ammonium sulfate capacity of 15 ten thousand tons/year.

A built-in main condenser (151) is arranged in the DTB neutralization crystallizer body (101), and a jet vacuum tail condensation system (200), a condensate system (300) and the like are arranged outside the neutralization crystallizer body (101); the jet vacuum tail condensation system (200) adopts a jet vacuum condenser (210) and is matched with a jet liquid system (400), and the process flow is shown in the attached figure 2.

The adding amount of ammonia gas and rearrangement liquid from the outside of the device is adjusted by a ratio, the ammonia gas is dissolved and absorbed into ammonia water by the condensate from the condensate return pipe (303), and the ammonia water and the rearrangement liquid enter the DTB neutralization crystallizer (101) through respective nozzles; an internal circulation is formed under the action of a guide shell (103) and a stirrer (108), the ammonium sulfate solution containing crystal grains is quickly raised to a boiling surface on the upper part of the guide shell, water begins to evaporate, crystal slurry flows downwards from the boiling surface along the outer side of the guide shell, the flow rate is reduced in a lower area on the outer side of the guide shell due to the change of the shape of a crystallizer, one part of suspension returns to the guide shell under the action of the stirrer, and the other part of suspension flows upwards to a baffling area (105). Crystals and amide oil are settled and separated due to the density difference in the baffling area (105), and an amide oil layer containing a small amount of ammonium sulfate solution is conveyed to a decanter in the device by an amide oil discharge pump (112) for re-layering; part of slurry containing ammonium sulfate crystal grains is pumped out from the middle part of the baffling area (105) by a crystallizer circulating pump (110), and ammonium sulfate-containing process water, unsaturated ammonium sulfate mother liquor sent by a subsequent process mother liquor circulating pump and other return condensate from the outside of the device are all connected to an inlet pipeline of the crystallizer circulating pump (110), are mixed with the circulating ammonium sulfate slurry in the pipeline and then return to a guide flow cylinder (103). When the solid content of ammonium sulfate at the bottom of the crystallizer (101) reaches a set value, ammonium sulfate slurry is pumped out from the bottom through a crystal slurry discharging pump (111) and is sent to a thickener in the device for thickening and separation.

The operating pressure at the top of the neutralization crystallizer, 15kPa (a), and the operating temperature, were about 60 ℃. 95% of the evaporated steam generated by neutralizing the crystallization heat is condensed on the shell side of the main condenser (151), condensate is collected (152) by a liquid collecting tank below the main condenser (151), flows into a liquid collecting hopper (153), is discharged out of the crystallizer (101) through a condensate discharging port (154), and automatically flows to a condensate system (300) through a condensate pipe (155), and the condensate direction is the same as that of the disclosed process technology.

The evaporation steam and the non-condensable gas which are not condensed by a main condenser (151) in the DTB neutralization crystallizer (101) are discharged from a vapor phase outlet at the top of the neutralization crystallizer (101) and an evaporation steam pipe (115) to a vapor phase inlet (216) of a tail condenser (210) to enter the tail condenser (jet type vacuum condenser, 210), are directly contacted with the jet liquid sprayed by an atomizing nozzle (212) to be condensed, components such as the non-condensable gas and the like are sucked by the jet liquid of a jet nozzle (213) to form vacuum, all fluids pass through a diffusion pipe (214) and a liquid collecting pipe (215) of the jet vacuum tail condenser (210), and are finally discharged into a jet liquid tank (401) of a jet liquid system (400) from a liquid outlet and a liquid discharging pipe (222) at the bottom of the jet vacuum tail condenser; the injection liquid in the injection liquid tank (401) is subjected to gas-liquid separation, the non-condensable gas is discharged from an exhaust port of the injection liquid tank (401) through a high-point discharge pipe (405), and the injection liquid flows from an injection liquid outlet of the injection liquid tank to an inlet of an injection liquid pump (402); the spraying liquid is pressurized by a spraying liquid pump (402), and is cooled to a specified temperature by circulating cooling water in a spraying liquid cooler (403), and then is circulated to the corresponding inlet pipes (220 and 221) of an atomizing spraying liquid cavity (217) and a vacuum spraying liquid cavity (218) of the spraying vacuum tail condenser, so that the spraying liquid is recycled; tapping a pipeline (119) from an outlet pipe (117) of a crystallizer circulating pump (110) to a liquid replenishing pipe (407) of a spraying liquid tank (401), and replenishing circulating liquid to a spraying liquid system (400); the injection liquid after the injection liquid system is balanced is discharged to a condensate tank (301) of a condensate system (300) through an overflow pipe (404) of an injection liquid tank (401), and finally returns to the crystallizer (101).

The main condenser (151) adopts a tube array type and extends into a heat exchange section in the crystallizer (101)The shell is not taken, 3 platforms are provided, and the specifications are as follows: phi 1100X4500, phi 1100X6000 and phi 1100X4500, and the total heat exchange area of the three heat exchangers is 1250m²Horizontally arranged in the upper vapor phase space of the crystallizer (101); the cooling medium is circulating cooling water, the temperature of the feeding water is about 34 ℃, the temperature of the outlet water is 40 ℃, and the water quantity is 1465m³/h。

The tail condenser (210) adopts a jet type vacuum condenser, which integrates jet condensation and vacuum equipment into a whole, and comprises 1 unit, the specification phi 900X2000, the inlet temperature of jet liquid is 39 ℃, the inlet temperature of the jet liquid is 43 ℃, and the top vacuum degree of the tail condenser is 14Kpa (a). The condensation in the tail condenser is with atomizing nozzle (212) and evacuation injection nozzle (213) sharing one set of injection liquid system (400), and main equipment has: an injection liquid tank (401), an injection liquid pump (402), and an injection liquid cooler (403).

Jet pump (402) main parameters: a lift of 35m and a flow rate of 150m³And h, the motor power is 22 kw.

Spray liquid cooler (403), 1 plate heat exchanger, heat exchange area 72m²The circulating cooling water entering the cooler is 494m³The temperature is raised to 33.8 ℃ by heat exchange of a spray liquid cooler, and then the temperature is mixed with the rest of cooling water passing through a bypass (409) in a cooling water pipe (410) to reach a cooling water inlet of the main condenser (151); the spray liquid at the outlet of the spray liquid cooler (403) is cooled to 39 ℃.

The amount of the circulating feed liquid supplemented to the injection liquid tank (401) by the crystallizer circulating pump (110) is 750 kg/h.

The utility project consumption of the technical scheme is as follows: electricity 19 kw; 1465m of circulating cooling water³H; no steam and no cryogenic cooling water is used.

Example 2:

the caprolactam re-drainage liquid and the ammonia neutralization crystallization device have the ammonium sulfate capacity of 15 ten thousand tons/year.

A built-in main condenser (151) is arranged in the DTB neutralization crystallizer body (101), and a spraying tail condensing system (200), a condensate system (300) and the like are arranged outside the neutralization crystallizer body (101); the spraying tail condensing system (200) adopts a spraying condenser (210) and is matched with a spraying liquid system (400); the vacuum facility is independent and adopts a liquid ring type vacuum system (500), and the process flow is as shown in figure 3.

The adding amount of ammonia gas and rearrangement liquid from the outside of the device is adjusted by a ratio, the ammonia gas is dissolved and absorbed into ammonia water by the condensate sent by the condensate return pipe (303), and the ammonia water and the rearrangement liquid enter the DTB neutralization crystallizer (101) through respective nozzles; an internal circulation is formed under the action of a guide shell (103) and a stirrer (108), the ammonium sulfate solution containing crystal grains is quickly raised to a boiling surface on the upper part of the guide shell, water begins to evaporate, crystal slurry flows downwards from the boiling surface along the outer side of the guide shell, the flow rate is reduced in a lower area on the outer side of the guide shell due to the change of the shape of a crystallizer, one part of suspension returns to the guide shell under the action of the stirrer, and the other part of suspension flows upwards to a baffling area (105). Crystals and amide oil are settled and separated in a baffling area (105) due to density difference, and an amide oil layer containing a small amount of ammonium sulfate solution is conveyed to a decanter in the device by an amide oil discharge pump (112) for re-layering; part of slurry containing ammonium sulfate crystal grains is pumped out from the middle part of the baffling area (105) by a crystallizer circulating pump (110), ammonium sulfate-containing process water from the outside of the device, unsaturated ammonium sulfate mother liquor from a subsequent process mother liquor circulating pump and the rest of returning condensate are all connected to an inlet pipeline of the crystallizer circulating pump (110), are mixed with the circulating ammonium sulfate slurry in the pipeline and then return to a guide flow cylinder (103). When the solid content of ammonium sulfate at the bottom of the crystallizer (101) reaches a set value, ammonium sulfate slurry is pumped out from the bottom through a crystal slurry discharging pump (111) and is sent to a thickener in the device for thickening and separation.

The operating pressure at the top of the neutralization crystallizer, 15kPa (a), and the operating temperature, were about 60 ℃. 95% of the evaporated steam generated by neutralizing the crystallization heat is condensed on the shell side of the main condenser (151), condensate is collected (152) by a liquid collecting tank below the main condenser (151), flows into a liquid collecting hopper (153), is discharged out of the crystallizer (101) through a condensate discharging port (154), and automatically flows to a condensate system (300) through a condensate pipe (155), and the condensate direction is the same as that of the disclosed process technology.

The evaporation steam and non-condensable gas which are not condensed by a main condenser (151) in the DTB neutralization crystallizer (101) are discharged from a vapor phase outlet at the top of the neutralization crystallizer (101) and an evaporation steam pipe (115) to a vapor phase inlet (216) of a tail condenser (210) to enter the tail condenser (jet tail condenser, 210), and are in countercurrent and direct contact with spray liquid sprayed by an atomizing nozzle (212) to be condensed, and the condensed liquid and the spray liquid fall into a liquid discharge pipe (222) at the lower part of the jet tail condenser (210) under the action of gravity to be discharged into a spray liquid tank (401) of a spray liquid system (400); non-condensable components such as non-condensable gas are discharged from a gas outlet at the top of the jet type tail condenser (210), are sucked to an inlet of a liquid ring vacuum pump (501) through a vacuum gas pipe (219) to form vacuum, and the gas is discharged from a gas-liquid separation tank (502) and is discharged at a high point through a non-condensable gas discharge pipe (505). The spraying liquid flows from a spraying liquid tank (401) to the inlet of a spraying liquid pump (402), is pressurized by the spraying liquid pump (402), is cooled to a specified temperature by circulating cooling water in a spraying liquid cooler (403), and then circulates to the inlet of an atomized spraying liquid cavity (217) of the spray type tail condenser (210), so that the spraying liquid is recycled; a circulating feed liquid pipe (217) is branched from an outlet of a crystallizer circulating pump (110) to a liquid replenishing pipe (407) of the spraying liquid tank (401), and the circulating feed liquid is replenished to the spraying liquid tank (401) in a spraying liquid system (400); working liquid of the liquid ring vacuum system (500) is supplemented to a liquid supplementing pipe (504) of the gas-liquid separation tank (502) through a pipeline (504) by a liquid injection pump (401); discharging the injection liquid after the injection liquid system is balanced to a condensate tank (301) of a condensate system (300) through an overflow pipe (404) of an injection liquid tank (401); the working fluid after the balance of the liquid ring vacuum system (500) is discharged to a condensate tank (301) of a condensate system (300) through a pipeline (506); and finally returned to the crystallizer (101).

The main condenser (151) adopts a tube array type, a heat exchange section extending into the crystallizer (101) does not have a shell, 3 heat exchange sections are provided, and the specifications are as follows: phi 1100X4500, phi 1100X6000 and phi 1100X4500, and the total heat exchange area of the three heat exchangers is 1250m²Horizontally arranged in the upper vapor phase space of the crystallizer (101); the cooling medium is circulating cooling water, the temperature of the feeding water is about 34 ℃, the temperature of the outlet water is 40 ℃, and the water quantity is 1465m³/h。

The tail condenser (210) adopts a jet condenser, and the tail condenser and the vacuum facility are respectively arranged. The jet type condenser comprises 1 jet type condenser, a specification phi 1000X1600 and a set of jet liquid system; the liquid ejecting system (400) mainly comprises: an injection liquid tank (401), an injection liquid pump (402), and an injection liquid cooler (403); the jet inlet temperature was 39 ℃, the jet inlet temperature was 43 ℃, and the vacuum at the top of the tail condenser was 13.5kpa (a).

Jet pump (402) main parameters: head 32m, flow 100m³And h, the motor power is 18.5 kw.

Spray liquid cooler (403), spray liquid cooler, 1 plate heat exchanger, heat exchange area 72m²(ii) a The water entering the cooler for circular cooling is 450m³The temperature of the circulating cooling water supply (408) is raised to 34 ℃ by heat exchange of a spray liquid cooler when the temperature is less than one third of that of the circulating cooling water supply (408) of the main condenser (151), and then the circulating cooling water is converged with the rest of the circulating cooling water passing through the cooling water bypass (409) in a cooling water pipe (410) and then enters a cooling water inlet of the main condenser (151); the spray was cooled to 39 ℃.

The liquid ring vacuum system (500) comprises a liquid ring vacuum pump (501), a gas-liquid separation tank (502), a working liquid cooler (503) and the like; the operating parameters are as follows: air extraction amount of 17m³Min, 13.0Kpa (a) of vacuum degree at the inlet of the liquid ring vacuum pump (501), 30kw of motor power and 20m of consumption of low-temperature cooling water³/h。

The amount of the circulating feed liquid supplemented to the injection liquid tank (401) by the crystallizer circulating pump (110) is 700 kg/h; the average value of the amount of the working fluid to be added to the gas-liquid separation tank (502) of the liquid ring vacuum system (500) by the jet pump (402) is 50 kg/h.

The technical scheme has the following common consumption conditions: newly adding 44kw of power consumption; 1465m of circulating cooling water³H; newly added low-temperature cooling water 20m³H; no steam is used.

Comparative example 1:

according to the production scale of example 1 and example 2, ammonium sulfate evaporative crystallization and neutralization crystallization in the production of caprolactam are compared with those in Wang-caprolactam [ J ]. China chemical trade, No. 3 in 2014, the neutralization reaction crystallization technology of the ammonium sulfate device of caprolactam is described, a DTB type neutralization crystallizer (101) is adopted, an external condenser (201) and a vacuum steam jet pump technology are adopted, and the process flow is shown as attached figure 4.

The operating pressure of the neutralization crystallizer is 15kPa (a), and the operating temperature is about 60 ℃. The vapor generated by the neutralization crystallization heat is discharged from a vapor phase outlet at the top of the neutralization crystallizer, enters a shell and tube surface condenser (201) through a vapor pipe (115), is condensed into condensate by circulating cooling water, and automatically flows to a condensate tank (301) through a condensate discharge pipe (206); the uncondensed gas discharged by the surface condenser (201) is pumped out by a steam jet vacuum pump; the steam jet vacuum pump is used for two-stage jet and consists of a first-stage steam jet pump (202), a first-stage jet condenser (203), a second-stage steam jet pump (204) and a second-stage jet condenser (205), discharged uncondensed gas is pumped out and pressurized from the uncondensed gas pipe (208) to the first-stage steam jet pump (202) and then condensed in the first-stage jet condenser (203), uncondensed gas is pumped out and pressurized from the uncondensed gas pipe to the second-stage steam jet pump (204), then further condensed in the second-stage jet condenser (205), and a small amount of uncondensed gas which is not condensed in the second-stage jet condenser (205) is discharged at a safe high point through an uncondensed gas discharge pipe (209); steam condensate water of the primary injection condenser (203) and the secondary injection condenser (205) automatically flows to a condensate tank (301) through a condensate discharge pipe (206), all condensate in the condensate tank (301) is pressurized by a condensate pump (302), the condensate is circulated back to the neutralization crystallization system (100) through a condensate return pipe (303) to balance evaporated water, a part of condensate is sent into an ammonia gas feeding pipeline to dissolve and absorb ammonia gas, a part of condensate is sent into an inlet pipeline of a crystallizer circulating pump (110) to dissolve fine crystals in circulating slurry, and a small part of condensate is used for washing each part and finally returns to the crystallizer (101).

The vacuum degree of the top of the neutralization crystallizer (101) is 15Kpa (a), the vacuum degree of the outlet of the surface condenser (201) is 12.5Kpa (a), the vacuum degree of the inlet of the first-level steam jet pump (202) is 12.0Kpa (a)

Comparative example 1 technical solution utility consumption: the power consumption is not increased newly and is marked as 0; circulating cooling water 1600m³H; the low-temperature cooling water is not consumed and is marked as 0; steam consumption 1200 kg/h.

Public price: steam, 150 yuan/t; electricity, 0.65 yuan/kw; circulating cooling water of 0.22 yuan/m³(ii) a Low cooling water of 0.5 yuan/m³。

The ammonium sulfate crystallization device with the capacity of 15 ten thousand tons/year of ammonium sulfate, the utility consumption and the calculated cost of the example 1, the example 2 and the comparative example 1 are compared, and the conditions are shown in the following table 1.

TABLE 1 comparison of the invention with the prior art

The above-mentioned only compares the difference between the utility consumption of the embodiment and the comparative example, if the production device is operated for 8000 hours per year, the cost of saving utility consumption per year by using a set of ammonium sulfate crystallization device of 15 ten thousand tons/year of the technology of the present invention is:

(538-334.65) x8000 ═ 1626800 (yuan/year)

The above-mentioned embodiments are only some examples of the present invention, and not intended to limit the present invention, that is, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art can make modifications or changes without departing from the spirit of the present invention, that is, the scope of the disclosure is defined by the claims.

Claims (15)

1. The utility model provides a caprolactam reliquefaction liquid and ammonia neutralization crystallization produce device of ammonium sulfate, includes DTB neutralization crystallizer, its characterized in that: a main condenser is arranged in the DTB neutralization crystallizer body, and a tail condenser and a condensate system are arranged outside the DTB neutralization crystallizer body.

2. The device for producing ammonium sulfate by caprolactam reliquefaction and ammonia neutralization crystallization according to claim 1, which is characterized in that: the main condenser is matched with a liquid collecting tank, a liquid collecting hopper, a condensate discharging port and a condensate pipeline; the tail condenser is matched with a vacuum facility and a liquid injection system.

3. The apparatus for producing ammonium sulfate by neutralization and crystallization of caprolactam re-drainage liquid and ammonia according to claim 1, characterized in that the heat exchange part or assembly of the main condenser is installed in the vapor phase space at the upper part of the DTB neutralization crystallizer, and the heat exchange section of the condenser in the neutralization crystallizer is not provided with a shell.

4. The device for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization as claimed in claim 1, characterized in that the DTB neutralization crystallizer upper vapor space is provided with a mounting hole corresponding to the cylinder wall, the mounting hole is welded with a short pipe having the same diameter as the main condenser shell toward the outside of the cylinder, the outlet end of the short pipe is provided with a flange, the flange connects and combines the main condenser, the main condenser pipe box and the short pipe, and the pipe box is provided with a cooling water inlet and a cooling water outlet and is respectively connected with an external cooling water pipeline.

5. The apparatus for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization as claimed in claim 2, wherein the liquid collecting tank is arranged right below the heat exchange part of the main condenser, and the liquid collecting area of the liquid collecting tank is not less than the projection area of the main condenser from the right above; the liquid collecting groove is in a groove form or is a circular arc-shaped plate with a baffle; the condensate outlet end of the liquid collecting tank is tightly connected with the inner side of the crystallizer cylinder, and the slope is towards the condensate outlet end and ranges from 1 degree to 10 degrees.

6. The apparatus for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization according to claim 2, wherein the collecting hopper is arranged at the inner side of the joint of the discharge end of the collecting tank and the cylinder of the DBT crystallizer, and the collecting hopper, the discharge end of the collecting tank and the cylinder of the crystallizer are tightly connected.

7. The device for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization according to claim 2, characterized in that the condensate discharge port is a pipe orifice arranged on the wall of the joint of the liquid collecting hopper and the crystallizer cylinder, and the bottom of the condensate discharge port is not higher than the bottom of the liquid collecting hopper; the condensate discharge port, the liquid collecting hopper, the main condenser and the liquid collecting tank are in one-to-one correspondence; the liquid collecting tank collects the condensate generated by the main condenser, and the condensate in the liquid collecting tank flows to the liquid collecting hopper and then automatically flows to the condensate system through the condensate discharging port and the external pipeline.

8. The device for producing ammonium sulfate by caprolactam reliquefaction and ammonia neutralization crystallization according to claim 2, which is characterized in that one or more groups of spraying facilities are arranged above the main condenser, one or more groups of spraying nozzles are arranged below the liquid collecting tank, and the spraying nozzles are connected with the condensate system.

9. The apparatus for producing ammonium sulfate by neutralization and crystallization of caprolactam re-drainage liquid and ammonia according to claim 2, characterized in that the tail condenser is a direct contact condenser or a dividing wall condenser; the direct contact condenser type is as follows: liquid column condenser, liquid film condenser, filling tower condenser and jet condenser.

10. The device for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization according to claim 9, characterized in that the upper space in the cavity of the jet condenser body is provided with a nozzle, the shell is provided with a vapor phase inlet and a jet liquid inlet, the lower part of the condenser is provided with a liquid collecting pipe, and the bottom of the condenser is provided with a liquid outlet; the nozzle is an atomizing nozzle.

11. The apparatus for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization according to claim 2, characterized in that the vacuum facility is one or more of a liquid jet vacuum pump, a liquid ring vacuum pump and a roots vacuum pump.

12. The apparatus for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization according to claim 9, wherein the ejector condenser and the liquid jet vacuum pump are independently arranged, and the non-condensable gas discharged from the ejector condenser is discharged to the liquid jet vacuum pump through an external pipeline; or the jet condenser and the liquid jet vacuum pump are combined into the jet vacuum condenser.

13. The device for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization according to claim 12, characterized in that the jet vacuum condenser is formed by embedding a liquid jet vacuum pump into a jet condenser cylinder, wherein an atomizing nozzle for condensation and cooling and a jet nozzle for vacuumizing are arranged at the upper part in the jet tail condenser cylinder from top to bottom, a diffusion pipe and a liquid collecting pipe are sequentially arranged at the lower part of the cylinder, and a liquid discharge port is arranged at the bottom; the atomization nozzle and the injection nozzle are respectively provided with an injection liquid inlet and an injection liquid cavity in the condenser shell and are connected with the outlet end of an injection liquid cooler of an injection liquid system through a pipeline; the spray nozzle is vertically installed, spray liquid is vertically sprayed downwards at a high speed through the spray nozzle, the non-condensable gas after atomized, condensed and cooled is sucked to form vacuum, and the spray liquid containing the condensed liquid and the non-condensable gas is discharged to a spray liquid tank of a spray liquid system from a bottom liquid discharge port through a diffusion pipe and a liquid collection pipe of a spray vacuum tail condenser.

14. The apparatus for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization according to claim 13, wherein the injection system mainly comprises an injection liquid tank, an injection liquid pump and an injection liquid cooler; the injection liquid tank is provided with an injection liquid return port, an injection liquid outlet, an overflow port and a liquid supplementing port, and the top of the injection liquid tank is provided with an exhaust port; the liquid outlet of the tail condenser is connected with the jet liquid tank, the jet liquid outlet is connected with the inlet of a jet liquid pump, the outlet of the jet liquid pump is connected with the inlet of a jet liquid cooler, and the outlet of the jet liquid cooler is connected with an atomizing nozzle and a jet liquid cavity corresponding to the jet nozzle in the jet vacuum tail condenser; the atomizing nozzle and the spray nozzle share one set of spray liquid system.

15. The apparatus for producing ammonium sulfate by caprolactam re-drainage and ammonia neutralization crystallization according to claim 14, wherein the spray liquid cooler is a dividing wall cooler, and is one or a combination of a tubular heat exchanger, a spiral plate heat exchanger and a plate heat exchanger.

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