CN208562198U - A kind of melamine complete alternation process units - Google Patents
A kind of melamine complete alternation process units Download PDFInfo
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- CN208562198U CN208562198U CN201820888395.7U CN201820888395U CN208562198U CN 208562198 U CN208562198 U CN 208562198U CN 201820888395 U CN201820888395 U CN 201820888395U CN 208562198 U CN208562198 U CN 208562198U
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Abstract
The utility model provides a kind of melamine complete alternation process units, enter in melamine reactor by raw material of liquid area, generate melamine, ammonia and carbon dioxide gas mixture material gas, through cooling, after purification separation, melamine is sublimated in chiller realizes gas solid separation for solid phase in efficient cyclone, melamine send packaging system, the gas containing ammonia and carbon dioxide come out from efficient cyclone enters combination high-efficiency wash cooling tower, gas after wash cooling cooling is pressurized into melamine reactor all the way, enter melamine reactor duplication of production melamine product after the excessively efficient urea synthesis conversion system synthetic fluid urea of a-road-through.What melamine processes tail gas the preparation technology of melamine of the utility model will not let alone to melamine preparation device battery limit (BL) outlet；It is environmental clean type device that melamine processes tail gas realizes that repeats itself utilizes inside melamine processes process units battery limit (BL), and accomplishes that melamine processes tail gas all realizes that efficient circulation utilizes in melamine processes process units.
Description
Technical field
The present invention relates to melamine preparation fields, and in particular to a kind of completely new melamine complete alternation process units,
Belong to chemical plant.
Background technique
The production technology of existing melamine, be all using the external world supply urea or liquid area as raw material, it is anti-into fluidized bed
Device is answered, reaction generates melamine, ammonia and carbon dioxide gas under 350-420 DEG C, 0-0.7MPa pressure, comes out from reactor
Material gas enter hot gas cooler, cooled down with road is raw to process gas, make it is high boiling point by-products produced come out with solid crystal, be cooled
Process stream gas afterwards enters the solid impurity in hot-air filter filtering gas, and filtered gas enters crystallizer and comes from
Liquid urinates the reverse contact heat-exchanging of technique cold air of washing system, and melamine is precipitated from process stream gas in solid form,
Then the gas of the solid containing melamine send packaging system after cyclone separator separates.The gas come out from cyclone separator is sent
To liquid urine washing system washing and cooling, the process gas after cooling divides three tunnels after separation, all the way as technique cold air by wind
Decrystallize device after machine compression (or directly), is done all the way as circulating air by dereaction device after compressor compresses (or directly) all the way
It is sent out outside melamine plant battery limit (BL) for preparation technology of melamine tail gas, the melamine outside melamine plant battery limit (BL) is raw out
Production. art tail gas need to create preparation technology of melamine tail gas absorption processing unit or outlet emptying device i.e. not environmentally energy conservation, again
Investment is wasted, and independent melamine processes vent gas treatment is also to perplex Melamine Production enterprise always for many years
Technology hang-up.Since preparation technology of melamine vent gas treatment particularity makes the production technology of present melamine run week
Phase greatly shortens, and considerably increases the various difficulty and manufacturing cost of Melamine Production.
The shortcomings that this preparation technology of melamine:
First is that because caused by the discontinuity of melamine processes tail gas absorption processing unit outside battery limit (BL) melamine processes fill
It is short to set runing time, 30-40 days or so devices of every operation will stop, and do total system cleaning, and it is big to clear up difficulty, cleaning
Time is up to two weeks, and expense is up to millions of members；
Second is that needing extraneous urea raw material supply, 6CO (NH is chemically reacted by melamine2)2==(NH2CN)3+3CO2+
6NH3Ton melamine theory needs 2.86 tons of urea, and ton melamine needs 3 tons of urea even higher in actual production.One
Urea raw material supply shortage suddenly in the denier external world is interrupted, and melamine processes device will be caused to stop.Moreover melamine processes
If emergency decompression melamine processes exhaust emissions is big environmental issue again after device parking.
Perplexing the technology hang-up of Melamine Production enterprise always in decades is exactly melamine processes vent gas treatment
Device can the economic independent operating of long period success, be evaluate Melamine Production Business Economic Benefit quality basic, be to determine
Determine enterprise and wins the key point lost.
Third is that melamine processes tail gas need to send melamine processes tail gas absorption processing unit or outlet dress outside battery limit (BL)
Set the investment cost for increasing vent gas treatment, and the ammonium hydroxide that these tail gas go production added value low more, ammonium hydrogen carbonate, liquid
Ammonia, nitro-compound fertilizer, soda ash etc..Fourth is that even if melamine processes tail gas to be sent to the original urea of enterprise after absorption is handled
Process units produces urea, will cause the reduction of the conversion rate of urea of the original urea plant of enterprise, urea production capacity
The irregular operation significantly increased with the original urea plant of enterprise with urea energy consumption is reduced, the original urine of enterprise is considerably increased
The management difficulty of plain process units.
Fifth is that melamine processes process units independent and melamine processes exhaust gas processing device operational process
In can generate a large amount of waste residue, exhaust gas, waste water, need overlapping investment to create waste residue, exhaust gas if need to handle, waste water environmental protection treatment is set
It applies, and treatment effect is undesirable, does not also accomplish resource circulation utilization.Moreover i.e. waste investment makes entire production technology chain stream again
Journey is complicated, and the device is complicated, and system complex is unfavorable for production safety management and production environmental protection management.
Sixth is that since entire production technology chain process complexity is cumbersome, until device area operator is excessive, hidden danger of keeping the safety in production
Excessively, safety and environmental protection production not can be effectively controlled.The above is to increase the throwing of melamine processes exhaust gas processing device
Money, and the dangerous feature of environmental protection production difficulty coefficient of Melamine Production and other devices is increased, once melamine processes
Exhaust gas processing device irregular operation or halt production will cause front end melamine processes process units irregular operation or halt production, again
By cause process tail gas emptying discharge and environmental protection it is not up to standard, the long period for not playing melamine processes process units is steady
Determine economical operation benefit.
Summary of the invention
In order to overcome six big defects of the above preparation technology of melamine, it is complete that the present invention provides a kind of completely new melamine
Cycle production process and device.
The technical solution of the utility model is:
A kind of melamine complete alternation process units efficiently synthesizes the liquid urine that urea conversion cycles liquid urinary system unit comes
Element is directly connect with melamine fluidized-bed reactor, and melamine fluidized-bed reactor is connect with hot gas cooler, and hot gas is cold
But device is connect with clarifier, and clarifier is connect with chiller, and chiller is connect with assembled highly-effective separator, assembled highly-effective separator
It is connected to product packaging systems and assembled highly-effective wash cooling tower.
Assembled highly-effective separator and assembled highly-effective wash cooling tower, assembled highly-effective wash cooling tower are connected through compressor all the way
To melamine fluidized-bed reactor；It is connected by circulation inside triamine tail gas all the way to efficient urea synthesis conversion cycles liquid urinary system
Unit efficiently synthesizes urea conversion cycles liquid urinary system unit and is connected to melamine fluidized-bed reactor and is formed and closed circuit follows entirely
Ring.
Assembled highly-effective wash cooling tower, which is connected to shunt on the pipeline of compressor, is connected to chiller, the assembled highly-effective
Wash cooling tower is pumped through medium solution and is connect with heat exchanger, and heat exchanger is connected to assembled highly-effective scrubber cooler and forms circulation.
Efficiently synthesizing urea conversion cycles liquid urinary system unit includes urea synthesis tower, and one section of M.P.decomposer, two sections low
Decomposer is pressed, urea synthesis tower is connect with one section of M.P.decomposer, and one section of M.P.decomposer is connect with two sections of low pressure decomposers, and two
Section low pressure decomposer is connect with flash concentration device, and flash concentration device is connect with primary concentration device, primary concentration device and second level
Enrichment facility connection, secondary concentration device are connected to melamine fluidized-bed reactor and form closed circuit complete alternation.
Lst-stage precipitation device is connected to one section of absorption plant through pipeline, one section of absorption plant connection first ammonium liquid high efficiency heater and
Liquefied ammonia high efficiency heater, first ammonium liquid high efficiency heater and liquefied ammonia high efficiency heater are connected to urea synthesis tower；Two sections of low pressure decompositions
Device is connected to two sections of absorption plants through pipeline, and two sections of absorption plants are connected to urea synthesis tower through one section of absorption plant；It flashes dense
Contracting device, primary concentration device, secondary concentration device are connect through pipeline with desorption hydrolysis device；Desorb hydrolysis device all the way through one,
Two sections of absorption plants are connected to urea synthesis tower, and desorption hydrolysis device another way is connected to urea cycle pond through pipeline and makees moisturizing
Form closed waste water complete alternation.
The completely new melamine complete alternation process units will not generate any trimerization in carrying out production process
Cyanamide process tail gas outlet will not generate any melamine processes waste water outlet, pass through special useless solid and wastewater treatment
Not any useless solid and waste water, the generation of exhaust gas have been technology this melamine complete alternation production technology in production
Complete environmentally protective cleansing preparation method of making technology.The production technology is with the self-produced liquid area of melamine complete alternation production technology device
Be directly entered in melamine reactor for raw material, under 350-420 DEG C, 0.1--2.6MPa pressure reaction generate melamine,
Ammonia and carbon dioxide gas, the material gas come out from reactor enters novel hot cooler energy byproduct steam simultaneously, novel net
Change device, the process gas containing melamine after purified device enters novel chiller, and melamine gas phase in chiller is sublimated
For solid phase, the melamine gas after Quench enters assembled highly-effective separator, and the solid melamine isolated send packaging system
System；The gas come out from assembled highly-effective separator enters assembled highly-effective wash cooling tower, in assembled highly-effective wash cooling Ta Neitong
It crosses washing medium and 200-230 DEG C of the gas containing ammonia and carbon dioxide is cooled into 130-145 DEG C, while by-product low-pressure steam.
Gas after cooling separates the droplet carried secretly in gas, the melamine processes gas one after separation by new and effective separator
Road directly returns melamine plant and passes through compressor compresses (or direct) into melamine reactor, and through Quench gas lift pressure
(or direct) enters chiller and does Quench use, and another way melamine processes tail gas is directly by efficiently synthesizing urea conversion cycles
One or more melamine reactor duplications of production three are directly all recycled into after liquid urinary system unit synthetic fluid urea
Paracyanogen amine product, melamine processes tail gas repeat directly by efficiently synthesizing the synthesis of urea conversion cycles liquid urinary system unit
Liquid area direct circulation enters melamine reactor, and in cycles, this sample preparation technology of melamine will not be to triamine
Device battery limit (BL) sends out any melamine processes tail gas outside, is environment-friendly type energy-saving device, and accomplishes melamine processes tail
Gas whole Efficient Conversion is the utilization of liquid charging stock urea repeats itself；External world's urea needed for Melamine Production is greatly reduced to disappear
Consumption can accomplish that producing ton melamine only consumes 1.5 tons of urea raw materials, is greatly saved Melamine Production cost and melamine
Amine plant investment construction cost.By special useless solid and waste water, waste gas treatment process technology produces melamine processes complete
The useless solid and waste water generated in the process, exhaust gas are all subject to resource circulation utilization, therefore referred to as complete alternation melamine clear production
Technique.The popular elaboration complete alternation melamine cleansing preparation method of making technological core of the technical solution of the utility model is exactly according to three
Poly cyanamid chemically reacts 6CO (NH2)2==C3H6N6+3CO2+6NH3Following two big steps of feeling the pulse with three fingers simulataneously carry out.
First step is all the advantageous items for making great efforts to create production of melamine to chemical reactive synthesis melamine product
Part, and realize that melamine product is successfully separated with melamine processes tail gas (mixed gas of gas ammonia and carbon dioxide)；Three
Paracyanogen amine product goes melamine packaging system, and melamine processes tail gas (the pure dry gas of the mixing of gas ammonia and carbon dioxide) is straight
It connects or boosted removes second step to 1.7--2.0Mpa.Second step is in the melamine reaction process come to first step
The melamine processes tail gas (the mixed gas base mole ratio of gas ammonia and carbon dioxide is 2-2.5:1) of generation is through the invention
It efficiently synthesizes urea conversion cycles liquid urinary system unit and directly converts liquid area for melamine processes tail gas and be recycled to
Melamine reactor is used as Melamine Production raw material.
According to urea reaction chemical formula 2NH3+CO2CO(N2)2+H2O is directly by melamine processes tail gas whole Efficient Conversion
Optimum reaction condition is selected to efficiently synthesize urea conversion cycles liquid urinary system unit (abbreviation triamine tail gas to design for liquid area
Unit) it due to originally efficiently synthesizing urea conversion cycles liquid urinary system unit is not traditional urea plant.Conventional urea device urine
Plain synthetic reaction is all that the net reaction of urea is pressed directly in urea synthesis tower in the case that the external world adds fresh carbon dioxide
2NH3+CO2(gas)==CO (NH2)2(liquid)+H2O (liquid)+Q is carried out in two steps synthetic reaction urea in urea synthesis tower.The
One step generates aminoquinoxaline, reaction equation are as follows: 2NH by ammonia and carbon dioxide3+CO2N2COONH4+308kcal/kg
This strong exothermal reaction spontaneously carries out, and as the heat put is pulled away, reaction will carry out complete.Second step amino first
Sour ammonium is dehydrated generation urea again, this is heat absorption reversible reaction carried out in the liquid phase: N2COONH4 CO(N2)2+H2O-
This is the chemical reaction of a heat absorption to 110kcal/kg urea, and reaction speed is slower, and the long period to can be only achieved balance, even if
Reach chemical balance, whole first ammonium dehydrations can not be made to be converted to urea.It is the control reaction during urea synthesis.
Originally efficiently synthesize urea conversion cycles liquid urinary system unit be in the case where not adding any fresh carbon dioxide,
Directly using ammonia in melamine processes tail gas, carbon dioxide goes urea synthesis, urea synthesis first step reacting ammonia and titanium dioxide
Carbon generates aminoquinoxaline (first ammonium liquid) exothermic reaction and fulfils ahead of schedule outside urea synthesis tower.Due to this technology utility model
There is no any extraneous fresh carbon dioxide to enter in urea synthesis tower and maintains urea synthesis without first ammonium liquid exothermic reaction heat
Second step aminoquinoxaline (first ammonium liquid) dehydration in tower generates the heat for the endothermic reaction that urea carries out；In 15.5-20.0MPa
The first ammonium fluid dewatering made under 186--189 DEG C of urea synthesis reaction condition in operating pressure urea synthesis tower reacts synthesis again
Liquid area reaction cannot proceed normally, it is necessary to by the aminoquinoxaline (first ammonium liquid) for having reacted completion outside synthesis urea tower
Preheat again outside tower, endlessly heat source supply brings into and maintains 186--189 DEG C of samming in urea synthesis tower, and first ammonium liquid is de-
Being hydrated into liquid area reaction just can be carried out.
So efficiently synthesizing urea conversion cycles liquid urinary system unit is arranged corrosion resistant amino outside a kind of urea synthesis tower
The novel first ammonium liquid high efficiency heater of ammonium formate (abbreviation first ammonium liquid) and liquefied ammonia high efficiency heater and tower internals go to realize urea synthesis
The regulation of 186--189 DEG C of liquid phase samming and technology condition realize the case where not adding any fresh carbon dioxide in tower
Under, it is the technology core for directly utilizing melamine processes tail gas synthetic fluid urea.Carbon dioxide is not being dosed completely
And directly using melamine processes tail gas come synthetic fluid urea, it is necessary to which selection is totally different from the work of traditional urea synthesizing
Skill technology, synthetic fluid urea optimum response technology side of the selection design when not adding any carbon dioxide gas
Case.It efficiently synthesizes urea conversion cycles liquid urinary system unit and does not add synthetic fluid urea in the case of any carbon dioxide gas
The selection of optimum response process technology scheme condition is as follows:
1, influence of the ammonia carbon ratio to synthesis conversion rate of urea (i.e. carbon dioxide conversion): in one timing of steam/hydrocarbons ratio, ammonia carbon
Than higher, CO2Conversion ratio increases；As ammonia carbon ratio (NH3/CO2)=2When Xco2 be 40%；As ammonia carbon ratio (NH3/CO2When)=3
XCO2It is 54%, as ammonia carbon ratio (NH3/CO2XCO when)=42It is 67.5%.From reaction balance it is found that increasing the concentration of reactant,
Reaction will be carried out to the direction for being conducive to product, when other conditions are identical, improve the ammonia carbon ratio of charging, then carbon dioxide is flat
The conversion ratio that weighs rises, in addition, excess of ammonia is also combined into NH4OH with another product water reacted, is more advantageous to the generation of urea,
But the saturated vapor pressure of object system increases rapidly with the raising of ammonia carbon ratio, while also increasing the internal circulating load of unreacted reactant ammonia,
Comprehensively consider, 3.8--4.6 is best ammonia carbon ratio.
2, steam/hydrocarbons ratio is the production of urea synthesis reaction to the influence water of synthesis conversion rate of urea (i.e. carbon dioxide conversion)
One of object, therefore, the addition of moisture content are always detrimental to the generation of urea, for originally efficiently synthesizing urea conversion cycles liquid urine system
It unites unit urea production process, unreacted ammonia and carbon dioxide is recovered is recycled back into urea synthesis tower, inevitably always
With a certain number of moisture content, for the influence for reducing water as far as possible, the moisture content into urea synthesis tower must reduce as much as possible,
This requires the lower the moisture content that unreacted ammonia and carbon dioxide recycle return to synthetic tower when institute band also should be the better.Therefore steam/hydrocarbons ratio
Increase, CO will be made2Conversion ratio decline；In urea production process, steam/hydrocarbons ratio (H2O/CO2) increase by 0.1, carbon dioxide conversion
Rate then reduces by 1%.
3, pressure is to the influence pressure of synthesis conversion rate of urea (i.e. carbon dioxide conversion) to carbon dioxide conversion
Influence: during urea synthesis, pressure is not an independent parameter, it is to rely on temperature, ammonia carbon ratio and steam/hydrocarbons ratio
Depending on.The operating pressure of urea synthesis is generally slightly higher compared with balance pressure.So-called balance pressure, which is reacted, to be reached between liquid phase
Physical equilibrium has also reached chemical balance, at this time the pressure of object system.If operating pressure is lower than balance pressure, not only ammonia is from liquid phase
Middle evolution reduces superfluous ammonia in liquid phase, while first ammonium can be made to decompose, to reduce CO2Conversion ratio.
4, influence of the residence time to synthesis conversion rate of urea (i.e. carbon dioxide conversion) determines that the residence time will be taken into account
Two aspect of production capacity of conversion ratio and factory, was necessary for the residence time about 50--70 minutes.The volume of urea synthesis tower
Size is also to design according to the residence time.Under the reaction condition that pressure is about 15.5--20.0MPa, the temperature of synthetic tower
186~189 DEG C of top, CO are risen to from 186 DEG C of bottom2Conversion ratio can reach 65--68%, unreacted CO2With first ammonium
Solution state is recycled, and takes moisture content to urea synthesis tower.Urea synthesis conversion ratio (i.e. carbon dioxide conversion) selects
In order to reach best synthetic fluid conversion rate of urea balance as far as possible, selecting following synthetic fluid urea in pressure is about 15.5--
Under the reaction condition of 20.0MPa:
186~189 DEG C of 186--189 DEG C of bottoms at the top of temperature
NH3/CO2(molecular proportion) 3.5--4.6
| H2O/CO2(molecular proportion) | ≤1.5 |
| Residence time | About 50--70 minutes |
5, in, low pressure decomposition absorb, from urea synthesis tower come out Synthesis liquid in have be not converted to urea first ammonium and
Superfluous ammonia.The generation reaction of first ammonium is the process of heat release and volume reduction, if decompression, heats unconverted first ammonium in Synthesis liquid
It is carried out to the direction for resolving into gaseous ammonia and carbon dioxide.Pressure is reduced, improves the temperature of solution, ammonia and carbon dioxide in solution
Gas solubility will be greatly reduced.So the operation for separating unconverted object from Synthesis liquid is needed using heating under reduced pressure, both
The decomposition for being conducive to first ammonium is also beneficial to make to be dissolved in superfluous ammonia and carbon dioxide gas in Synthesis liquid and distills.Separation
Ammonia, carbon dioxide and water out absorbs to form first ammonium liquid recycling to urea synthesis tower by the condensate liquid evaporated.Middle pressure point
Middle pressure decomposition hydraulic coupling after solution, which is decompressed to 0.25--0.4MPa by 1.6--1.75MPa, makes the middle part first ammonium pressed in decomposed solution
It is decomposed into ammonia and carbon dioxide gas.Into low pressure decomposition top of tower middle pressure decomposed solution by tower top pass through packing layer rectifying
Section, continuous flow down finally enter heater base, and undecomposed first ammonium further decomposes in decomposed solution, then from heating
Come out at the top of device and enter low pressure decomposition separator, the gas that separator comes out by blast cap by packing layer rectifying section it is continuous on
It rises, carries out heat and mass transfer, the solution that the higher water vapour of boiling point in gas phase is constantly flow down by tower top condenses, urine
In after undecomposed first ammonium heated by gas, constantly decompose and be gasificated into ammonia and CO2, so overhead gas is mainly high concentration
Ammonia and CO2, the aqueous solution of the mainly urea of tower bottom discharge.By one, two section of mesolow decompose to synthesis urea tower go out liquid into
Row concentrate, the urine qualified to melamine reactor conveying, meanwhile, recycle the unreacted reactant decomposited, the unreacted of recycling
Object returns to urea synthesis tower in form of an aqueous solutions.It is the technique skill for efficiently synthesizing urea conversion cycles liquid urinary system unit above
Art scheme, but originally efficiently synthesizing urea conversion cycles liquid urinary system unit also includes to efficiently synthesize urea conversion isothermal internals to set
It is standby and efficiently synthesize urea combination separate absorbent concentrator and technology operation condition.Pass through first step and second step
Successful realization, this two big step perfection constitutes complete alternation melamine cleansing preparation method of making technology.
The melamine fluidized-bed reactor, hot gas cooler has also been devised in the utility model, and hot gas purification device swashs
Cooler efficiently synthesizes urea conversion cycles liquid urinary system, melamine finished product conveying and packaging system etc., is the special of special construction
There is a melamine fluidized-bed reactor, hot gas cooler, New purifier, novel chiller efficiently synthesizes urea conversion cycles
Liquid urinary system unit (also efficiently adds comprising the novel first ammonium liquid of corrosion resistant aminoquinoxaline (first ammonium liquid) outside a kind of urea synthesis tower
186--189 DEG C of liquid phase samming regulation efficiently synthesizes urea converter in hot device, liquefied ammonia high efficiency heater and a kind of urea synthesis tower
Internals and its corresponding technology condition and efficiently synthesize urea combination separate absorbent concentrator and technology condition) etc..
The utility model simplifies preparation technology of melamine, directly with liquid urine self-produced in preparation technology of melamine
Element circulation production melamine, by using special technique and device systems and useless solid and waste water, waste gas treatment process skill
Art is all subject to resource circulation utilization, really does to useless solid and waste water, the exhaust gas that generate in melamine processes production overall process
To environmentally protective, saving energy and cost, therefore referred to as melamine complete alternation production technology.
The characteristics of production technology of the utility model, is:
Urea is efficiently synthesized 1. generating melamine processes tail gas in Melamine Production reaction process and directly passing through to enter
One or more melamine reactor weights are directly all recycled into after conversion cycles liquid urinary system unit synthetic fluid urea
Demutation produces melamine product, and melamine processes tail gas is generated in melamine reaction process and is repeated directly by efficiently closing
At direct circulation enters melamine reactor, Zhou Erfu again after urea conversion cycles liquid urinary system unit synthetic fluid urea
Begin, it is ring that melamine processes tail gas this sample preparation technology of melamine will not let alone to melamine battery limit (BL) outlet
Lustration type melamine plant is protected, and accomplishes that melamine processes tail gas whole efficient circulation utilizes, and substantially reduce saving
Melamine Production cost and greatly reduce melamine plant investment cost.In the melamine complete alternation production technology
Due to using novel proprietary technique and device systems, the cycle of operation of melamine plant is also greatly prolonged.Technology production
Ton melamine can consume 1.5 tons of urea raw materials.
2. it is even higher that traditional melamine processes technology production ton melamine will consume 3 tons of urea raw materials.Tradition three
Poly cyanamid process unit is all not include melamine processes exhaust gas processing device, to generating in Melamine Production reaction process
A large amount of melamine processes tail gas all send out outside melamine processes device battery limit (BL)s and reprocessed, the other investment construction of need
Dedicated for the device of melamine processes vent gas treatment, the present invention is very well by Melamine Production Devices and melamine
Being closely as one of both process tail gas processing units, realize Melamine Production and melamine tail gas utilize it is complete
Circulation production melamine processes, and in triamine production process by special environmental protection technology generated it is useless consolidate and it is useless
Water, exhaust gas are all subject to resource circulation utilization, are truly realized environmentally protective, saving energy and cost complete alternation production.
3. melamine processes tail gas is turned by efficiently synthesizing urea in complete alternation melamine cleansing preparation method of making
Change circulation fluid urinary system unit synthetic fluid urea, which passes through the height in melamine processes device
Urea synthesis conversion cycles liquid urinary system unit synthetic fluid urea is imitated, efficient isothermal synthesis internals make urea synthesis conversion ratio
(i.e. carbon dioxide conversion) is even higher up to 65--68%.Its subsequent circulation fluid urinary system circulation of urea synthesis high conversion rate
Measure small, urea synthesis conversion energy consumption substantially reduces, and power consumption and steam consumption reduce；This melamine processes tail gas is entirely pure dry
Process tail gas, be free of any moisture, tail gas directly it is pressurized or be not pressurized be directly entered efficiently synthesize urea conversion fluid urine circulation
System unit synthetic fluid urea synthesizing conversion ratio increases substantially, and urea following cycle amount greatly reduces, and urea synthesis is comprehensive
Energy consumption reduces, and urea synthesis conversion ratio (i.e. carbon dioxide conversion) is up to 65--68% or so.
Existing melamine processes tail gas be all through melamine processes device outside separately build melamine processes tail gas
Processing unit directly carries out adding water or adds weak aqua ammonia or plus dilute first to the melamine processes tail gas that melamine processes device comes
Ammonium fluid is made in the absorption of ammonium liquid or first ammonium liquid send melamine processes tail gas recycling device to remove production ammonium hydroxide, ammonium bicarbonate, urine again
Element, soda ash, nitro-compound fertilizer etc.；Because of plus water or add weak aqua ammonia or add all can be straight containing large quantity of moisture in dilute first ammonium liquid absorbent
Connect or take to indirectly ammonium bicarbonate, urea, soda ash causes the original system of these process units horizontal in nitro-compound fertilizer process units
The destruction of weighing apparatus need to establish the balance and Carbon balance of new process material, cause these ammonium bicarbonates, urea, soda ash, nitro-compound fertilizer production
The reduction of the carbon dioxide conversion of device and production waste water, the discharge amount of exhaust gas increase, and cause the energy consumption of process units and each
Item management difficulty increases.
4. traditional preparation technology of melamine, byproduct steam amount is extremely low, only consumes steam, or even not by-product；This complete alternation
The a large amount of steam of melamine clear production process by-product 1.27MPa and 0.15MPa, institute's producing steam are directly efficiently synthesized urea and are turned
Change circulation fluid urinary system unit to use, it is less that steam is mended in the external world.
5. melamine complete alternation production technology is without useless solid and waste water, the generation of exhaust gas, waste water, the whole row up to standard of exhaust gas
It puts.
6. the entire technological process of production of melamine complete alternation production technology is succinctly simple, due to realizing system sis
It is controlled with DCS, until device area operator is greatly reduced, effective control is fully achieved to safety and environmental protection production.
7. being avoided by cancelling triamine vent gas treatment independent operating device because triamine vent gas treatment independent operating device stops
Vehicle stops influence caused by melamine plant, can be by melamine plant continuous operation cycle stretch-out by 180 days, even more
It is long；Due to the proprietary fluidized-bed reactor and fixed bed reactors of special designing, hot gas quenching cooler, novel hot purification
Device, novel chiller efficiently synthesize urea conversion cycles liquid urinary system unit, melamine finished product conveying and packaging system equipment and
Special technical data.
This melamine complete alternation production process and device simplifies preparation technology of melamine process, Melamine Production
Process tail gas realizes that within battery limit Efficient Conversion has that process is simple, the cycle of operation at liquid area raw material whole cycling and reutilization
Long, safety and environmental protection eliminates potential risk, there is one-time investment to save, and production run is at low cost, and management difficulty is small, peace
The advantages that loopful is protected.Ton melamine can consume 1.5 tons of urea raw materials and consume 3 tons than traditional melamine processes ton melamine
Urea raw material will save at least 1.5 tons of urea raw materials.
Detailed description of the invention
Fig. 1 is the technological process of production schematic diagram of existing melamine.
Fig. 2 is melamine complete alternation technological process of production rough schematic of the invention.
Fig. 3 efficiently synthesizes urea conversion cycles liquid urinary system cellular manufacture process flow diagram for of the invention.
Fig. 4 is melamine complete alternation technological process of production schematic diagram of the invention.
Specific embodiment
Embodiment 1
A kind of device of melamine complete alternation production technology efficiently synthesizes what urea conversion cycles liquid urinary system unit came
Liquid area is directly connect with melamine fluidized-bed reactor, and melamine fluidized-bed reactor is connect with hot gas cooler,
Hot gas cooler is connect with clarifier, and clarifier is connect with chiller, and chiller is connect with assembled highly-effective separator, assembled highly-effective
Separator is connected to product packaging systems and assembled highly-effective wash cooling tower.The assembled highly-effective separator is washed with assembled highly-effective
Cooling tower is washed, assembled highly-effective wash cooling tower is connected to melamine fluidized-bed reactor through compressor all the way；Triamine tail all the way
It is connected by circulation inside gas to efficient urea synthesis conversion cycles liquid urinary system unit, efficiently synthesizes urea conversion cycles liquid urinary system
Unit is connected to melamine fluidized-bed reactor and forms closed circuit complete alternation.The assembled highly-effective wash cooling tower is connected to pressure
It is shunted on the pipeline of contracting machine and is connected to chiller, the assembled highly-effective wash cooling tower connects through medium solution pump with heat exchanger
It connects, heat exchanger is connected to assembled highly-effective scrubber cooler and forms circulation.
The described urea conversion cycles liquid urinary system unit that efficiently synthesizes includes urea synthesis tower, one section of M.P.decomposer,
Two sections of low pressure decomposers, which is characterized in that urea synthesis tower is connect with one section of M.P.decomposer, one section of M.P.decomposer and two sections
Low pressure decomposer connection, two sections of low pressure decomposers are connect with flash concentration device, and flash concentration device is connect with primary concentration device, and one
Grade enrichment facility connect with secondary concentration device, secondary concentration device be connected to melamine fluidized-bed reactor formed it is closed circuit entirely
Circulation.
The lst-stage precipitation device is connected to one section of absorption plant through pipeline, and one section of absorption plant connection first ammonium liquid efficiently adds
Hot device and liquefied ammonia high efficiency heater, first ammonium liquid high efficiency heater and liquefied ammonia high efficiency heater are connected to urea synthesis tower；Two sections low
Decomposer is pressed to be connected to two sections of absorption plants through pipeline, two sections of absorption plants are connected to urea synthesis tower through one section of absorption plant；
Flash concentration device, primary concentration device, secondary concentration device are connect through pipeline with desorption hydrolysis device；Desorb hydrolysis device all the way
It is connected to urea synthesis tower through one, two section of absorption plant, hydrolysis device another way is desorbed through pipeline and is connected to urea cycle pond
Make moisturizing and forms closed waste water complete alternation.
Embodiment 2
A kind of melamine complete alternation production technology, includes the following steps:
(1) enter in melamine fluidized-bed reactor by raw material of liquid area, in 350-420 DEG C, 0.1~2.6MPa
Reaction generates melamine, ammonia and carbon dioxide gas mixture material gas under pressure；
(2) from melamine reactor come out mixed material gas enter hot gas cooler 350-420 DEG C, 0.1~
Under 2.6MPa pressure, it is cooled to 320--340 DEG C, after purified separation, the process gas containing melamine enters chiller, trimerization
Cyanamide is sublimated in this gas phase as solid phase, and the process gas containing melamine after Quench enters assembled highly-effective separator, isolates
Solid melamine send packaging system；Melamine processes gas is efficiently synthesized urea conversion cycles liquid urinary system unit Synthesis liquid
Body urea cycle returns to melamine reactor and is re-used as melamine reaction raw material.
(3) enter combination high-efficiency wash cooling from the gas containing ammonia and carbon dioxide that assembled highly-effective separator comes out
The 200-230 DEG C of gas scrubbing containing ammonia and carbon dioxide is cooled in combined type washing cooling tower by wash cooling by tower
130-145 DEG C, the gas after cooling is pressurized into melamine reactor all the way, and the excessively efficient urea synthesis conversion of a-road-through follows
Enter one or several melamine reactor duplication of production melamine products after ring liquid urinary system unit synthetic fluid urea.
It efficiently synthesizes urea conversion cycles liquid urinary system unit and does not add conjunction in the case of any carbon dioxide gas
It is selected at liquid area optimum response process technology scheme condition as follows:
1, influence of the ammonia carbon ratio to synthesis conversion rate of urea (i.e. carbon dioxide conversion): in one timing of steam/hydrocarbons ratio, ammonia carbon
Than higher, CO2Conversion ratio increases；As ammonia carbon ratio (NH3/CO2Xco2 is 40% when)=2；As ammonia carbon ratio (NH3/CO2X when)=3
CO2It is 54%, as ammonia carbon ratio (NH3/CO2X CO when)=42It is 67.5%.From reaction balance it is found that increasing the concentration of reactant,
Reaction will be carried out to the direction for being conducive to product, when other conditions are identical, improve the ammonia carbon ratio of charging, then carbon dioxide is flat
The conversion ratio that weighs rises, in addition, excess of ammonia is also combined into NH4OH with another product water reacted, is more advantageous to the generation of urea,
But the saturated vapor pressure of object system increases rapidly with the raising of ammonia carbon ratio, while also increasing the internal circulating load of unreacted reactant ammonia,
Comprehensively consider, 3.8--4.6 is best ammonia carbon ratio.
2, influence of the steam/hydrocarbons ratio to synthesis conversion rate of urea (i.e. carbon dioxide conversion): water is the production of urea synthesis reaction
One of object, therefore, the addition of moisture content are always detrimental to the generation of urea, for originally efficiently synthesizing urea conversion cycles liquid urine system
It unites unit urea production process, unreacted ammonia and carbon dioxide is recovered is recycled back into urea synthesis tower, inevitably always
With a certain number of moisture content, for the influence for reducing water as far as possible, the moisture content into urea synthesis tower must reduce as much as possible,
This requires the lower the moisture content that unreacted ammonia and carbon dioxide recycle return to synthetic tower when institute band also should be the better.Therefore steam/hydrocarbons ratio
Increase, CO will be made2Conversion ratio decline；In urea production process, steam/hydrocarbons ratio (H2O/CO2) increase by 0.1, carbon dioxide conversion
Rate then reduces by 1%.
3, influence of the pressure to synthesis conversion rate of urea (i.e. carbon dioxide conversion): pressure is to carbon dioxide conversion
Influence: during urea synthesis, pressure is not an independent parameter, it is to rely on temperature, ammonia carbon ratio and steam/hydrocarbons ratio
Depending on.The operating pressure of urea synthesis is generally slightly higher compared with balance pressure.So-called balance pressure, which is reacted, to be reached between liquid phase
Physical equilibrium has also reached chemical balance, at this time the pressure of object system.If operating pressure is lower than balance pressure, not only ammonia is from liquid phase
Middle evolution reduces superfluous ammonia in liquid phase, while first ammonium can be made to decompose, to reduce CO2Conversion ratio.
4, influence of the residence time to synthesis conversion rate of urea (i.e. carbon dioxide conversion): determine that the residence time will be taken into account
Two aspect of production capacity of conversion ratio and factory, was necessary for the residence time about 50--70 minutes.The volume of urea synthesis tower
Size is also to design according to the residence time.Under the reaction condition that pressure is about 15.5--20.0MPa, the temperature of synthetic tower
186~189 DEG C of top, CO are risen to from 186 DEG C of bottom2Conversion ratio can reach 65--68%, unreacted CO2With first ammonium
Solution state is recycled, and takes moisture content to urea synthesis tower.
Urea synthesis conversion ratio (i.e. carbon dioxide conversion) selection is to reach best synthetic fluid urea as far as possible
Conversion ratio balance, selects following synthetic fluid urea under the reaction condition that pressure is about 15.5--20.0MPa: at the top of temperature
186~189 DEG C of 186--189 DEG C of bottoms
NH3/CO2(molecular proportion) 3.5--4.6
5, in, low pressure decomposition absorb: from urea synthesis tower come out Synthesis liquid in have be not converted to urea first ammonium and
Superfluous ammonia.The generation reaction of first ammonium is the process of heat release and volume reduction, if decompression, heats unconverted first ammonium in Synthesis liquid
It is carried out to the direction for resolving into gaseous ammonia and carbon dioxide.Pressure is reduced, improves the temperature of solution, ammonia and carbon dioxide in solution
Gas solubility will be greatly reduced.So the operation for separating unconverted object from Synthesis liquid is needed using heating under reduced pressure, both
The decomposition for being conducive to first ammonium is also beneficial to make to be dissolved in superfluous ammonia and carbon dioxide gas in Synthesis liquid and distills.Separation
Ammonia, carbon dioxide and water out absorbs to form first ammonium liquid recycling to urea synthesis tower by the condensate liquid evaporated.It is pressed in
Middle pressure decomposed solution after decomposition, pressure are decompressed to 0.25--0.4MPa by 1.6--1.75MPa, make the part in middle pressure decomposed solution
First ammonium is decomposed into ammonia and carbon dioxide gas.Middle pressure decomposed solution into low pressure decomposition top of tower passes through packing layer by tower top
Rectifying section, continuous flow down finally enter heater base, and undecomposed first ammonium further decomposes in decomposed solution, then from
It is come out at the top of heater and enters low pressure decomposition separator, the gas that separator comes out is continuous by the rectifying section of packing layer by blast cap
Rise, carry out heat and mass transfer, the solution that the higher water vapour of boiling point in gas phase is constantly flow down by tower top condenses, and urinates
After undecomposed first ammonium is heated by gas in liquid, ammonia and CO are constantly decomposed and are gasificated into2, so overhead gas is mainly high concentration
Ammonia and CO2, the aqueous solution of the mainly urea of tower bottom discharge.It is decomposed by one, two section of mesolow and liquid is gone out to synthesis urea tower
Carry out concentrate, the urine qualified to melamine reactor conveying, meanwhile, recycle the unreacted reactant decomposited, recycling it is not anti-
Object is answered to return to urea synthesis tower in form of an aqueous solutions.It is the technique for efficiently synthesizing urea conversion cycles liquid urinary system unit above
Technical solution, but originally efficiently synthesizing urea conversion cycles liquid urinary system unit also includes to efficiently synthesize urea conversion isothermal internals
Equipment and efficiently synthesize urea combination separate absorbent concentrator and technical data.
Fig. 3 efficiently synthesizes urea conversion cycles liquid urinary system cellular manufacture process flow diagram for the application's.
Fig. 3 explanation: the urea conversion cycles liquid urinary system unit that efficiently synthesizes of the invention is only a kind of trimerization of the invention
One unit part of cyanamide complete alternation production technology, melamine processes tail gas are directly entered one or two sections of decomposing systems of this unit
And one or two sections of absorption systems, when any fresh carbon dioxide is not added, the liquid area for reacting synthesis is directly entered trimerization
Cyanamide reactor is reused as melamine raw material, and similarly reaction generation melamine processes tail gas, which repeats, is converted into liquid
Urea is used as melamine feedstock circulation.By the successful realization of first step and second step, this two big step is perfect
Constitute complete alternation melamine cleansing preparation method of making technology.So in melamine complete alternation production process and device of the present invention
In to efficiently synthesize urea conversion cycles liquid urinary system unit be that corrosion resistant aminoquinoxaline (first outside a kind of urea synthesis tower is arranged
Ammonium liquid) novel first ammonium liquid high efficiency heater, liquefied ammonia high efficiency heater and urea tower internals is efficiently synthesized to realize urea synthesis tower
Interior 186--189 DEG C of liquid phase samming regulation and technology condition be not in the case where realization adds any fresh carbon dioxide, directly
Connect the technology core using melamine processes tail gas synthetic fluid urea.
It is had the following beneficial effects: using technical solution of the present invention
Claims (5)
1. a kind of melamine complete alternation process units, which is characterized in that efficiently synthesize urea conversion cycles liquid urinary system unit
The liquid area come is directly connect with melamine fluidized-bed reactor, and melamine fluidized-bed reactor and hot gas cooler connect
It connects, hot gas cooler is connect with clarifier, and clarifier is connect with chiller, and chiller is connect with assembled highly-effective separator, combination
Efficient cyclone is connected to product packaging systems and assembled highly-effective wash cooling tower.
2. melamine complete alternation process units according to claim 1, which is characterized in that assembled highly-effective separator and group
High-efficient washing cooling tower is closed, assembled highly-effective wash cooling tower is connected to melamine fluidized-bed reactor through compressor all the way；One
It is connected by circulation inside the triamine tail gas of road to efficient urea synthesis conversion cycles liquid urinary system unit, efficiently synthesizes urea conversion cycles
Liquid urinary system unit is connected to melamine fluidized-bed reactor and forms closed circuit complete alternation.
3. melamine complete alternation process units according to claim 1, which is characterized in that assembled highly-effective wash cooling tower
It is connected to shunt on the pipeline of compressor and is connected to chiller, the assembled highly-effective wash cooling tower is pumped and changed through medium solution
Hot device connection, heat exchanger are connected to assembled highly-effective scrubber cooler and form circulation.
4. melamine complete alternation process units according to claim 1, which is characterized in that efficiently synthesize urea conversion and follow
Ring liquid urinary system unit includes urea synthesis tower, one section of M.P.decomposer, two sections of low pressure decomposers, in urea synthesis tower and one section
Decomposer connection is pressed, one section of M.P.decomposer is connect with two sections of low pressure decomposers, and two sections of low pressure decomposers and flash concentration device connect
It connects, flash concentration device is connect with primary concentration device, and primary concentration device is connect with secondary concentration device, and secondary concentration device connects
It is connected to melamine fluidized-bed reactor and forms closed circuit complete alternation.
5. melamine complete alternation process units according to claim 1, which is characterized in that lst-stage precipitation device connects through pipeline
It is connected to one section of absorption plant, one section of absorption plant connection first ammonium liquid high efficiency heater and liquefied ammonia high efficiency heater, first ammonium liquid are efficient
Heater and liquefied ammonia high efficiency heater are connected to urea synthesis tower；Two sections of low pressure decomposers are connected to two sections of absorption dresses through pipeline
It sets, two sections of absorption plants are connected to urea synthesis tower through one section of absorption plant；Flash concentration device, primary concentration device, second level are dense
Compression apparatus is connect through pipeline with desorption hydrolysis device；Desorption hydrolysis device is connected to synthesis urine through one, two section of absorption plant all the way
Plain tower, desorption hydrolysis device another way are connected to urea cycle pond through pipeline and make moisturizing formation closed waste water complete alternation.
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