CN208471948U - A kind of Melamine Production system - Google Patents

Abstract

The utility model belongs to chemical field, provides a kind of Melamine Production system, i.e., realizes that melamine gas is sublimated crystallization using fluidized-bed crystallizer technology.Its system features are as follows: the carrier gas containing melamine gas after filtering fluidizes in fluidized-bed crystallizer, and crystallisation by cooling is carried out simultaneously, gas after crystallization is after separating melamine solid powder, directly Carrier Gas Compressor is gone to pressurize, carrier gas as reactor, it eliminates cold gas system and liquid urine washing system, system flow greatly simplifies.In fluidized-bed crystallizer, high temperature carrier gas is recycled in such a way that water vapor generates high-grade steam and melamine crystallizes heat.

Description

A kind of Melamine Production system

Technical field

The utility model belongs to chemical field, is related to a kind of Melamine Production system.

Background technique

Currently, melamine is usually produced by raw material of urea, production method can be divided into low-pressure process and two kinds of high-pressure process.

High-pressure process Melamine Production system belongs to liquid phase reactor, no catalyst.Reaction pressure is generally 7~20MPa, instead Answering temperature is 360~420 DEG C.

High-pressure process Melamine Production system generally uses liquefied ammonia, ammonium hydroxide or mother liquor etc. to quench as liquid phase quenching medium It is cold, melamine product can be just obtained after need to refining.

The advantages of high-pressure process is tail gas (ammonia and carbon dioxide) pressure height, can directly return to urea plant, can be effectively reduced Material loss；It is re-refined the disadvantage is that liquid phase quenching medium need to be introduced and carry out quenching, system flow is long, steam consumption height (production per ton Product need to consume 6~10 tons of steam), and have waste water generation in production process.

Low-pressure process Melamine Production system belongs to gas phase catalytic reaction, is generally urged with aluminium oxide, Alusil or silica gel Agent.Reaction pressure is generally 0.1~0.7MPa, and reaction temperature is 350~450 DEG C.

Low-pressure process Melamine Production system generally uses gas phase quenching system to post-process reaction product, i.e., with ammonia Gaseous mixture with carbon dioxide is the crystallization and purification that quenching medium completes product.

The advantages of low-pressure process is that system flow is shorter, and equipment investment is less, and no waste water generates；Its disadvantage: first is that tail gas pressure Power is low, cannot be routed directly to urea plant utilization.Second is that since system pressure is low, power consumption it is high (product per ton need power consumption 800~ 1500 degree).Third is that contour size of the unit(s) is big since system pressure is low, it is unfavorable for the enlargement of device.

Existing low-pressure process gas phase quenching system has the disadvantage in that

1. heat utilization rate is low.

Melamine is crystallized by cold air quenching, and heat generates 0.1~0.3MPa steam through urea washes system.Due to Steam pressure is low, and grade is low, can not utilize, and generally uses air cooler cooling to remove heat, causes the waste of amount of heat (melamine per ton about generates 4 tons of steam).

2. power consumption is high.

Low-pressure process gas phase quenching system needs a large amount of cold air crystallizations, and air conditioning quantity is about 4 times of load volume, Cool gas blower The operation power that power is more than Carrier Gas Compressor is run, the power consumption of melamine Cool gas blower per ton is about 300 degree.

Low-pressure process gas phase quenching system needs a large amount of liquid urine circulation washings, and melamine liquid urine circulating pump power consumption per ton is about 50 degree.

3. tail gas cannot be routed directly to urea plant utilization.

Because low-pressure process gas phase quenching system pressure is low, vent gas treatment is difficult, can only be absorbed with water, cannot be routed directly to urea Device utilizes, and vent gas treatment is at high cost.

4. unstable product quality.

Low-pressure process gas phase quenching system, because cold gas system uses urea washes, the seriously corrodeds such as equipment and pipeline often go out There is the case where stain in existing product, unstable product quality seriously affects the use of product.

5. device enlargement is difficult.

In low-pressure process gas phase quenching system, since system pressure is low, contour size of the unit(s) is big, and device enlargement is difficult.

For the defect of low-pressure process gas phase quenching system, domestic some research and development institutions propose a kind of recirculating fluidized bed crystallizer Technology.The characteristics of technology is the structure that recirculating fluidized bed adds companion's bed using main bed, and internal cyclone separators and heat exchanger tube is arranged Beam.A large amount of crystallization heat is removed using the phase transformation of heat exchange liquid in pipe, to maintain crystallization temperature at 220 DEG C or so.

Melamine in the recirculating fluidized bed crystallizer is circulated in main bed and between bed.Since melamine is solid The feeder pipe of the poor fluidity of body powder, internal cyclone separators is easy blocking, and device is caused to be unable to run.

Summary of the invention

One of the purpose of this utility model is to provide a kind of Melamine Production system that heat utilization rate is high.

Another of the utility model is designed to provide a kind of Melamine Production system that power consumption is low.

Another of the utility model is designed to provide a kind of Melamine Production system of process simplification.

The utility model another be designed to provide it is a kind of can long-term safety and normal use Melamine Production System.

The purpose of this utility model is achieved through the following technical solutions:

A kind of Melamine Production system, comprising:

Reactor: first charging aperture and second charging aperture including being set to reactor lower part, first charging aperture position is higher than Fused salt heating tube, for being passed through fusing urea, second charging aperture is located at the bottom of reactor, for being passed through carrier gas, discharge port position In reactor head, reaction gas for generating in output-response device, fused salt heating tube is located at reactor lower part, for reaction Device provides heat.

Hot gas cooler: being connected with reactor outlet, for cooling down reaction gas.

Hot-air filter: being connected with hot gas cooler outlet, for filtering catalyst fines and by-product in reaction gas Equal impurity.

Fluidized-bed crystallizer: including be set to fluidized-bed crystallizer lower part first charging aperture (not crystallizing gas import), second Feed inlet (solid inlet of cyclone separator separation) and third feed inlet (solid inlet of sack cleaner separation).First Feed inlet is located at the bottom of fluidized-bed crystallizer, and for being passed through non-crystallizing gas, second charging aperture position is lower than cooling device, uses Return to fluidized-bed crystallizer in the melamine powder that separates cyclone separator, third gating location lower than second into Material mouth, the melamine powder for separating sack cleaner return to fluidized-bed crystallizer.

In addition, fluidized-bed crystallizer also includes the outlet of the first discharge port-crystallization gas, the second discharge port-products export.First Discharge port is located at the top of fluidized-bed crystallizer, and for exporting the gas after crystallizing, the second discharge port is located under fluidized-bed crystallizer Portion, position is lower than third feed inlet, for exporting melamine product.

In fluidized-bed crystallizer comprising positioned at the gas distributor of bottom, the cooling device above gas distributor, And the gear gas deduster above cooling device.The top of gas distributor and the lower space of gear gas deduster are solid Grain emulsion zone.An idle space is provided between gas distributor and cooling device.

Gas distributor includes a gas distributor and secondary air distributor, and a gas distributor includes more A nozzle for being distributed in basic same level；The secondary air distributor is the plate with multiple apertures, is located at described one Above secondary gas distributor.

Preferably, the secondary air distributor can against a gas distributor and be set to a gas distributor Top；The described gas distributor and gas inlet communication is not crystallized, preferably pass through pipeline connection.

Open Side Down for the nozzle, for example, towards crystalliser feet or at an angle towards crystalliser feet.When Bottom is loaded into melamine in shell, and when not crystallizing gas and initially entering crystallizer, gas is equably sprayed from each nozzle down Out, and melamine solid particle loss formation fluidisation is blown, at this point, the upper space formation solid particle of gas distributor is close Phase region, and lower section forms bottom solid particle dilute-phase zone due to the effect of nozzle and porous plate；After stopping fluidisation, melamine Amine largely will slowly be fallen after rise, at this point, secondary air distributor (porous plate) plays the larger a part of melamine of barrier simultaneously It falls after rise to the effect of bottom, to solve the problems, such as that gas distributor is easy blocking.

Preferably, the nozzle includes the pipeline of spray orifice and the extension outside spray orifice, at an angle towards crystallization Device bottom.

Above-mentioned certain angle for example may be greater than 0 ° less than 45 °.

By using the setting of the gas distributor of the utility model, remained to when can make the diameter of crystallizer up to 8 meters Trouble-free operation.

In a preferred embodiment of the utility model, a gas distributor include it is multiple be distributed in it is conplane Ring pipe, ring pipe are connected by radial branched pipe, and each radial branched pipe is summarized in central tube, and central tube is Connection does not crystallize the pipeline of gas import Yu a gas distributor.Nozzle is connected on ring pipe, to be distributed evenly in crystallization In device.

In the emulsion zone of fluidized-bed crystallizer, cooling device, the preferred heat-exchanger rig of cooling device are arranged.Heat exchange dress Setting has a water inlet and a steam (vapor) outlet；The water inlet is connected to the drum water outlet for being set to drum bottom, described Steam (vapor) outlet is connected to the steam inlet for being set to drum.Heat-exchanger rig includes many heat exchanger tubes, and medium is water in heat exchanger tube.Trimerization The water in crystallization heat heating heat exchanger tube in cyanamide bed, makes water vapor, steam water interface rises to fluidized bed by outlet header In drum outside crystallizer, the steam after separating water is drawn by steam (vapor) outlet general pipeline, and the water separated flows into fluidisation by potential difference The water inlet general pipeline of bed crystallizer heat exchanger tube lower part, forms Natural Circulation.

The drum is located above fluidized-bed crystallizer, is connected with the heat-exchanger rig in fluidized-bed crystallizer.Specifically, Drum water outlet and steam inlet are connected with the water inlet of heat-exchanger rig and steam (vapor) outlet respectively.The steam (vapor) outlet of the drum Equipped with pressure-regulating valve, the pressure for vaporization of water is controlled by pressure-regulating valve to control corresponding vapourizing temperature.Due to drum with Steam in heat-exchanger rig forms natural cycle system, as long as pressure is invariable, temperature also can be invariable, melamine bed Layer would not overtemperature.

In the top of cooling device, it is provided with gear gas deduster.By the gear gas deduster, can abolish in crystallizer Air pocket, while a large amount of melamines carried secretly in gas being separated, make to enter crystallizer hull outside cyclone separator Gas in melamine concentration substantially reduce, alleviate the load of cyclone separator, improve cyclone separator separation effect Fruit.Embodiment as one preferred, the gear gas deduster are the sieve-like component being made of multiple claw-like intersection constructions. Claw-like intersection construction forms certain overlay region up and down and certain hollowed out area, thus forms into down space point The sieve texture of cloth (distributed in three dimensions).Keeping off gas deduster has two layers or more, and the claw-like structures of every layer of gear gas deduster are perpendicular It is interspersed.

It is important to note that the setting of the gear gas deduster is very favorable, the outstanding gear gas deduster use In the most melamine particles of blocking.Gear gas deduster be preferably provided with two layers or more gear gas remove knoisphere, more preferable three layers with Upper gear gas removes knoisphere.In the enclosure interior, gas distributor top spaced apart is provided with for obstructing solid Grain gear gas deduster, the gear gas deduster can be perforated panel (such as with multiple round, rectangular or other shapes holes), Or netted, sieve-like component, preferably with two layers or more in the perforated panel or netted, sieve-like being mutually distributed up and down Component.When crystallizing gas passes through the gear gas deduster together with solid particle, gas can continue to diffuse on gear gas deduster The space of side, and melamine solid particle is blocked in the sky kept off below gas deduster by biggish resistance to most of Between, thus, until the space above gas distributor is the solid particle emulsion zone in crystallizer, trimerization below gear gas deduster Cyanamide is fully utilized, and crystallization is cooling with the progress of higher rate, and the upper space for keeping off gas deduster forms another Solid particle dilute-phase zone, in order to which gas is further finally efficiently separated with melamine.

In the crystallization processes of melamine, carrier gas+melamine gas enters close phase by gas distributor from bottom Area, the emulsion zone are limited between the two by gas distributor and gear gas deduster, are contained in the emulsion zone being consequently formed Solids ratios are high, and so as to form high heat transfer coefficient, high heat transfer coefficient is very for the crystallization of melamine Important, this is because heat transfer coefficient is high, heat transfer temperature difference can be reduced, the vapourizing temperature of water side is improved, to generate high-grade Steam.

The lower space of emulsion zone needs to be empty, and upper space is then equipped with cooling device.The space being available is practical It is upper to be used as crystal region, because it was found that, violent crystallization reaction occurs in the lower space, only by segment space sky It sets, can just crystalline particle be prevented to be bonded on tube wall, guarantee the trouble-free operation of crystallizer.

Another improvement of the utility model is that the bottom of cyclone separator is equipped with Loop Seal；It preferably, is machine Tool formula Loop Seal；It is further preferable that being scraper.The returning charge structure can by the melamine particulate powders separated and When send the crystal region of fluidized-bed crystallizer lower part back to, make the emulsion zone height of fluidized-bed crystallizer keep stablizing, to maintain to fluidize The stable operation of bed crystallizer.

An important design is the construction and its external whirlwind configured of crystallizer in the system of the utility model Separator.The overall structure of crystallizer in Tthe utility model system has used for reference the Chinese patent of the patent No. 201410255842.1 The methanation fluidized-bed reactor of middle record.

But in the crystallization art of melamine, always nobody was used, also always nobody imagined using gas-gas type It reacts fluidizer and is used as gas-solid formula crystallization apparatus, this is because the viscosity of melamine is very big, solid particle flow is poor, Crystallisation by cooling is easy knot wall, and the engineering difficulty crystallized using fluidized-bed crystallizer is big.

And the utility model is found by cleverly application, the principle of fluidized bed reaction can be used for melamine Crystallization, may make melamine to be crystallized in real fluidized state, this results in huge benefits: it can make three Poly cyanamid crystallization is sufficiently complete, while generating a large amount of high-grade steam, and heat utilization ratio greatly improves.

Preferably, the shell in the gas distributor top position is equipped with a separation solid inlet-cyclone separator point From solid inlet；The incoming end of the external cyclone is connected with crystallization gas outlet, external cyclone Output end with separate solid inlet be connected.

But compared to methanation fluidized bed, the equipment of the utility model needs particularly to set external for cyclone separator (and the cyclone separator of methanation fluidized bed is then that fluidized-bed reactor enclosure interior is arranged in) of formula.This is because such as The blanking principle of cyclone separator in methanation fluidized bed be by be arranged lower end a baiting valve, by weight of material with The balance of enclosure interior air pressure carrys out blanking.But if in melamine use built-in cyclone separator, but entirely without Method operationalizes, and the solid particle separated in cyclone separator can not be utilized this due to sticky too big, poor fluidity Relationship between weight of material and air pressure and voluntarily fall, but retain in separator, result in blockage.Therefore, by whirlwind point Outside is set to from device to be very important for the crystallization process of melamine.It is optional by external force such as mechanical force It ground can be by it from output in external hanging type cyclone separator to the separation solid inlet on shell, because dividing in cyclone separator at this time It is smaller to separate out the grain diameter come, further returns to enclosure interior crystal region and is crystallized again, can produce granular size more Suitable crystalline particle.

In the prior art, a kind of recirculating fluidized bed crystallizer is disclosed in 95213850.6 utility model of the patent No., due to Melamine particulate powders poor fluidity, recirculating fluidized bed circulation is difficult, and internal cyclone separators feeder pipe is easy blocking, makes It fails at internal cyclone separators, it is difficult to realize industrialization.

The utility model uses external hanging type cyclone separator, separates the melamine particulate powders of entrainment, and in whirlwind Loop Seal is installed in the bottom of separator, and the melamine particulate powders separated are sent back under fluidized-bed crystallizer in time The crystal region in portion makes the emulsion zone height of fluidized-bed crystallizer keep stablizing, to maintain the stable operation of fluidized-bed crystallizer.

The ingehious design of the crystallizer and application, so that can be with by the melamine that reactor exports in the production system It efficiently sublimates from gaseous state as solid crystal, so that the configuration of system and the system flow comparison prior art can be greatly simple Change.

Preferably, Melamine Production equipment provided by the utility model also contains deduster, preferably sack cleaner.Bag Formula deduster is connected with Cyclone outlet, for separating the melamine particulate powders carried secretly in gas；This is practical new Type further improvement lies in that, the bottom of sack cleaner is equipped with Loop Seal, it is preferable that be mechanical Loop Seal, example Such as scraper.The Loop Seal can be by the melamine particulate powders separated in time by sending fluidized-bed crystallizer back to The crystal region of lower part makes the emulsion zone height of fluidized-bed crystallizer keep stablizing, to maintain the stable operation of fluidized-bed crystallizer.

It is highly preferred that being additionally provided with a solid below the cyclone separator separation solid inlet on the shell of crystallizer and entering The solid inlet of mouth-sack cleaner separation；The sack cleaner incoming end is connected with the outlet of cyclone separator, pocket type The output end of deduster be set to fluidized bed crystallizer on sack cleaner separate solid inlet separate solid inlet be connected.

Further, Melamine Production system provided by the utility model also contains carrier gas system, the carrier gas system packet Include Carrier Gas Compressor, carrier gas preheater and the fused salt circulatory system.Carrier Gas Compressor is connected with carrier gas preheater, carrier gas preheater with Reactor is connected.The fused salt circulatory system includes fused salt storage tank equipped with pump for liquid salts, the fused salt being connected with fused salt storage tank Furnace, the fused salt heating tube being connected with molten salt furnace；Fused salt heating tube is located in reactor, for maintaining catalytic bed temperature.

After Carrier Gas Compressor compressed carrier gas, into carrier gas preheater, after fused salt heats, reaction is entered by reactor bottom Device, by the catalyst fluidization in reactor.Fusing urea from urea workshop section sprays into reactor through spray gun, makees in catalyst Melamine is generated with lower reaction.Reactor lower part is equipped with fused salt heating tube, for providing heat to reactor, to maintain to be catalyzed Agent bed temperature.

Further, Melamine Production system provided by the utility model, it is characterised in that also contain condenser, preferably Ground is road raw food condenser.Road raw food condenser is connected with hot gas cooler to be connected, and hot gas cooler is made to use the raw liquid cooling in road but.

The system of the utility model and existing low-pressure process gas phase quenching systematic comparison, key problem in technology are:

1. replacing original cold air quenching crystallizer using fluidized-bed crystallizer.

Former cold air quenching crystallizer is mixed using 140 DEG C of cold air with 340 DEG C of hot gas, and the temperature after crystallization is controlled at 220 DEG C, Since crystallizer is void tower form, hot and cold gas mixing is uneven, be easy to cause local overcooling, crystalline rate is low, product quality It is unstable；The utility model is crystallized using fluidized-bed crystallizer, and uniformity of temperature profile in crystallizer, the temperature difference is small, and crystalline rate is high, Good product quality.

2. fluidized-bed crystallizer replaces original urea washes that air cooler is added to exchange heat using water vapor phase-change heat-exchange.

Existing low-pressure process gas phase quenching system uses urea washes method, will come out from triamine trap, and temperature is 220 DEG C Gas scrubbing it is cooling, to obtain the cold air that temperature is 140 DEG C or so, while cooling using air cooler, distribute heat to big In gas；The utility model fluidized-bed crystallizer uses water vapor phase-change heat-exchange so that the crystallization of melamine and it is cooling simultaneously into Row, and 1.5MPa high-grade steam is generated, heat is all recycled.

3. the cold gas system and urea washes system, system flow and equipment cancelled in former process greatly simplify.

Existing low-pressure process gas phase quenching system, crystallizes cold air in order to obtain, it is necessary to use urea washes, and use air cooler It is cooling, while using Cool gas blower by circulating cold air.Its cold gas system by process sequence successively include Cool gas blower, crystallizer, Triamine trap, urea washes tower, cold air demister.Urea washes system successively includes urea washes tower, liquid by process sequence Urinate circulating pump, air cooler.For the utility model because not needing cold air crystallization, the cold gas system and urea washes system in former process are equal It is cancelled, system flow and equipment greatly simplify.

Melamine Production system provided by the utility model has the advantage that

1. heat utilization rate is high.

The utility model Melamine Production Technology makes high-grade heat due to using fluidized-bed crystallizer crystallization technique It is recycled, and generates a large amount of high-grade steam (melamine per ton generates about 4 tons of 1.5MPa steam), heat utilization rate is big Amplitude improves.

2. power consumption is low.

The utility model Melamine Production Technology adds system pressure due to eliminating Cool gas blower and liquid urine circulating pump The raising of power, the power consumption of Carrier Gas Compressor can also reduce, and with existing low-pressure process gas phase quenching systematic comparison, estimate melamine per ton The power consumption of amine reduces about 400 degree, and power savings are clearly.

3. investing small.

The Melamine Production Technology of the utility model is due to eliminating cold gas system and urea washes system, process letter Change, eliminates the large scale equipments such as Cool gas blower, urea washes tower, air cooler, cold air demister, liquid urine circulating pump, equipment investment Sharp fall.About 30% is reduced with the investment of existing low-pressure process gas phase quenching systematic comparison, identical scale set.

4. tail gas can be routed directly to urea plant utilization.

The utility model Melamine Production Technology due to system pressure height, tail gas is compressed to 2.5 through tail-gas compressor~ 3.5MPa is cooled to 100~200 DEG C into carbamate condenser, and tail gas condensing becomes liquid first ammonium liquid, and first ammonium liquid is added by ammonium carbamate pump Enter urea synthesizer, the urea synthesis in urea synthesizer after being depressed into 20.0 MPa.Because tail gas is absorbed without water, water is avoided The steam consumption of urea is greatly lowered in influence to urea synthesizer conversion ratio.

5. good product quality.

Existing low-pressure process gas phase quenching system, because cold gas system use urea washes, the seriously corrodeds such as equipment and pipeline, Often occur having the case where stain in product, seriously affects the use of product.The Melamine Production Technology of the utility model by In eliminating urea washes system, the corrosion such as equipment and pipeline mitigate significantly, do not have the case where stain in product, which can expire The requirement of sufficient high-end user.

6. device enlargement easy to accomplish.

For the Melamine Production Technology of the utility model due to system pressure height, contour size of the unit(s) is small, and device is easy real Existing enlargement.

Detailed description of the invention

Fig. 1 shows a kind of Melamine Production system of one specific embodiment of the utility model.

1- fluidized-bed crystallizer 1.1- cooling device

2- Carrier Gas Compressor 3- pump for liquid salts

4- fused salt basin 5- carrier gas preheater

6- molten salt furnace 7- fused salt heating tube

8- hot gas cooler 9- condenser

10- hot-air filter 11- reactor

12- drum 13- pressure-regulating valve

The Loop Seal of 14- cyclone separator 14.1- cyclone separator

15- sack cleaner 15.1- rotary back-blowing device

The Loop Seal of 15.2- deduster

Fig. 2 shows the systems of existing low-pressure process gas phase quenching.

A- reactor B-Carrier Gas Compressor

C- pump for liquid salts D- fused salt basin

E- carrier gas preheater F- molten salt furnace

The road G- hot gas cooler H- raw food condenser

I- hot-air filter J- crystallizer

K- triamine trap L- urea washes tower

M- air cooler N- cold air demister

O- Cool gas blower P- liquid urinates circulating pump

Q- fused salt heating tube

Fig. 3 shows the melamine fluidized-bed crystallizer structural schematic diagram of a specific embodiment of the invention.

1.1- cooling device 1.2- gas distributor

Gas distributor 1.2b- secondary air distributor of 1.2a-

1.3- gear gas deduster 1.4- does not crystallize gas import

1.5- solid particle outlet 1.6- feeds intake entrance

The solid inlet 1.8- water inlet general pipeline of 1.7- cyclone separator separation

1.9- steam (vapor) outlet general pipeline 1.10- feeds intake entrance

1.11- shell 1.12- crystallizes gas outlet

1.13- feeds intake entrance 1.14- products export

1.15- water inlet 1.16- steam (vapor) outlet

The solid inlet 12- drum of 1.17- sack cleaner separation

12.1- drum steam inlet 12.2- drum water outlet

12.3- drum steam (vapor) outlet 12.4- water inlet

12.5- water compensating valve 13- pressure-regulating valve

The Loop Seal of 14- cyclone separator 14.1- cyclone separator

14.2- cyclone separator output end 14.3- cyclone separator input terminal

14.4- process gas exports

Specific embodiment

A kind of Melamine Production system of embodiment 1

As shown in Figure 1, a kind of Melamine Production system, including reactor 11, the hot gas being connected is exported with reactor 11 Cooler 8, exports the hot-air filter 10 being connected with hot gas cooler 8, exports the fluidized bed knot being connected with hot-air filter 10 Brilliant device 1, the cyclone separator 14 being connected with fluidized-bed crystallizer 1, the sack cleaner 15 being connected with cyclone separator 14.

Shown in reactor lower part have a first charging aperture and second charging aperture, first charging aperture position is heated higher than fused salt Pipe, for being passed through fusing urea, second charging aperture is located at the bottom of reactor, for being passed through carrier gas.Discharge port is located at reactor Top, the reaction gas for generating in output-response device, fused salt heating tube are located at reactor lower part, for providing heat to reactor Amount.

Shown in the outlet of hot gas cooler 8 and reactor 11 be connected, for cooling down reaction gas.

Shown in the outlet of hot-air filter 10 and hot gas cooler 8 be connected, for filtering the catalyst fines in reaction gas And the impurity such as by-product.

Shown in the outlet of cyclone separator 14 and fluidized-bed crystallizer 1 be connected, for separating the melamine carried secretly in gas Amine.The bottom installation Loop Seal 14.1 (being scraper in the present embodiment) of cyclone separator 14, the melamine that will be separated Particulate powders send the crystal region of 1 lower part of fluidized-bed crystallizer back in time.

Shown in the outlet of sack cleaner 15 and cyclone separator 14 be connected, for separating the melamine carried secretly in gas Particulate powders；Further improvement of the utility model is that 15.2 (this reality of Loop Seal is installed in the bottom of sack cleaner 15 Apply in example as scraper), the melamine particulate powders separated are sent back to the crystallization of 1 lower part of fluidized-bed crystallizer in time Area makes the emulsion zone height of fluidized-bed crystallizer 1 keep stablizing, to maintain the stable operation of fluidized-bed crystallizer.Bag-type dusting It is also equipped with rotary back-blowing device 15.1 in device 15, using rotary back-blowing technology, had both improved blowback effect, and had in turn ensured equipment Long-term operation.

Melamine Production system as shown in Figure 1, also contains carrier gas system.Carrier gas system includes Carrier Gas Compressor 2, carries Air preheater 5 and the fused salt circulatory system；Carrier Gas Compressor 2 is connected with carrier gas preheater 5, carrier gas preheater 5 and 11 phase of reactor Even；The fused salt circulatory system includes fused salt storage tank 4 equipped with pump for liquid salts 3, is connected with fused salt storage tank 4 molten salt furnace 6, with The connected fused salt heating tube 7 of molten salt furnace 6；Fused salt heating tube 7 is located in reactor 11, for maintaining catalytic bed temperature.

Melamine Production system as shown in Figure 1 also contains road raw food condenser 9, road raw food condenser 9 and hot gas cooler 8 are connected, and hot gas cooler 8 is made to use the raw liquid cooling in road but.

Fluidized-bed crystallizer 1 shown in as shown in figure 3, includes the vertical cylinder shell 1.11 that upper and lower ends are end socket, 1.11 lower head of circular cylindrical shell, which is equipped with, does not crystallize gas import 1.4, and 1.11 upper cover of shell is equipped with crystallization gas outlet 1.12, position Gas distributor 1.2 is equipped at the space of bottom close in shell 1.11.Gas distributor 1.2 includes a gas distributor 1.2a and secondary air distributor 1.2b, a gas distributor 1.2a include multiple being distributed in basic same level Nozzle；The secondary air distributor 1.2b is the plate with multiple apertures, is located at below the gas distributor 1.2a.

Gas distributor 1.2a include it is multiple be distributed in conplane ring pipe, ring pipe passes through radial branch Pipe is connected, and each radial branched pipe is summarized in central tube, and central tube is to be connected to not crystallizing gas import and a gas The pipeline of distributor.Nozzle is connected on ring pipe, to be distributed evenly in crystallizer.The nozzle towards crystallizer Bottom.

Inside the shell 1.11 shown in, the top spaced apart of gas distributor 1.2 is provided with cooling device 1.1 (being heat-exchanger rig in the present embodiment).Heat-exchanger rig is by many set of heat exchange tubes at medium is water in heat exchanger tube.Melamine The water in crystallization heat heating heat exchanger tube in bed, makes water vapor, steam water interface is come out by steam (vapor) outlet general pipeline 1.9, through vapour Packet steam inlet 12.1 enters in drum 12, and the steam after separating water is drawn through drum steam (vapor) outlet 12.3, the water separated The water inlet general pipeline 1.8 for flowing into fluidized-bed crystallizer heat exchanger tube lower part by potential difference through drum water out 12.2, forms Natural Circulation.

Shown in drum water outlet (12.2) and drum steam inlet (12.1) respectively with the water inlet of cooling device (1.15) it is connected with steam (vapor) outlet (1.16).The water of drum is controlled by water compensating valve 12.5, enters drum 12 through water inlet 12.4 Interior, the steam (vapor) outlet 12.3 of drum 12 is equipped with pressure-regulating valve 13, controls the pressure for vaporization of water by pressure-regulating valve 13 to control Make corresponding vapourizing temperature.

Inside shown shell 1.11, the top spaced apart of cooling device 1.1 is provided with for obstructing solid The gear gas deduster 1.3 of grain.Keeping off gas deduster 1.3 is the sieve-like component being made of multiple claw-like intersection constructions.Claw-like cross knot It has been configured to certain overlay region up and down and certain hollowed out area, has thus formed into upper and lower spatial distribution (three-dimensional point Cloth) sieve texture.Keeping off gas deduster 1.3 has two layers (can also be three layers or three layers or more), and every layer of claw-like structures are in vertical Directly it is interspersed.

Crystallization gas outlet 1.12 is connect with external cyclone input terminal 14.3 at the top of fluidized-bed crystallizer.External whirlwind Separator 14 further separates melamine powder.Process gas outlet 14.4 of the external cyclone 14 containing top, it is external Cyclone separator output end 14.2.In the bottom of cyclone separator, Loop Seal 14.1 (being scraper in the present embodiment) is also installed, The melamine particulate powders separated are sent back to the knot of 1 lower part of fluidized-bed crystallizer in time through separating solid inlet 1.7 In crystalline region.

The process gas outlet 14.4 that external cyclone contains top is connect with sack cleaner 15.Sack cleaner 15 Bottom is equipped with rotary back-blowing device 15.1, and Loop Seal 15.2 (being scraper in the present embodiment) is also installed in bottom, will be under separation The melamine particulate powders come are sent back in the crystal region of 1 lower part of fluidized-bed crystallizer in time through separating solid inlet 1.17.

A kind of preparation technology of melamine system of table 1 compared with the overall target of existing low-pressure process gas phase quenching system (with 1 ton of melamine meter of every production)

Claims (9)

1. a kind of Melamine Production system, which is characterized in that including reactor (11), export the heat being connected with reactor (11) Gas Cooler (8) exports the hot-air filter (10) being connected with hot gas cooler (8), is connected with hot-air filter (10) outlet Fluidized-bed crystallizer (1), be located at that fluidized-bed crystallizer (1) is external and the whirlwind that is connected with the fluidized-bed crystallizer (1) divides From device (14), the sack cleaner (15) being connected with the cyclone separator (14), the crystallizer (1) contains a shell (1.11), comprising being located at the gas distributor (1.2) of bottom, being located above gas distributor (1.2) inside shell (1.11) Cooling device (1.1) and the gear gas deduster (1.3) being located above cooling device (1.1).

2. Melamine Production system according to claim 1, which is characterized in that the gas distributor (1.2) point For a gas distributor (1.2a) and secondary air distributor (1.2b)；A vacant sky is equipped with above gas distributor (1.2) Between；Space above has cooling device (1.1)；The cooling device (1.1) is heat-exchanger rig, the heat exchanger tube with multiple groups parallel connection.

3. Melamine Production system according to claim 1, which is characterized in that the gear gas deduster (1.3) is equipped with Two layers or more gear gas removes knoisphere.

4. Melamine Production system according to claim 1, which is characterized in that also contain drum (12), the drum (12) it is located above fluidized-bed crystallizer (1), is connected with the cooling device (1.1) in fluidized-bed crystallizer (1)；The drum (12) contain drum water outlet (12.2), drum water outlet (12.2) and steam inlet (12.1) enter with the water of cooling device respectively Mouth (1.15) is connected with steam (vapor) outlet (1.16).

5. Melamine Production system according to claim 1, which is characterized in that the bottom of the cyclone separator (14) The Loop Seal (14.1) of cyclone separator is installed；The Loop Seal (14.1) of the cyclone separator is mechanical returning charge machine Structure.

6. Melamine Production system according to claim 1, which is characterized in that the sack cleaner (15) is equipped with Rotary back-blowing device (15.1)；The Loop Seal (15.2) of the bottom installation deduster of sack cleaner (15)；Deduster returns Expect that mechanism (15.2) are mechanical Loop Seal.

7. Melamine Production system according to claim 4, which is characterized in that the drum (12) is also steamed containing drum Vapor outlet (12.3)；The drum steam (vapor) outlet (12.3) is equipped with pressure-regulating valve (13).

8. Melamine Production system according to claim 1, which is characterized in that also contain carrier gas system, the carrier gas system System includes Carrier Gas Compressor (2), carrier gas preheater (5) and the fused salt circulatory system；Carrier Gas Compressor (2) and carrier gas preheater (5) It is connected, carrier gas preheater (5) is connected with reactor (11)；The fused salt circulatory system includes molten equipped with pump for liquid salts (3) Salt basin (4), the molten salt furnace (6) being connected with fused salt basin, the fused salt heating tube (7) being connected with molten salt furnace (6)；Fused salt heating tube (7) it is located in reactor (11).

9. Melamine Production system according to claim 1, which is characterized in that also (9) containing condenser, condenser (9) It is connected with hot gas cooler (8), hot gas cooler is made to use the raw liquid cooling in road but.