CN102728316A

CN102728316A - Magnesium-salt ammonia storage mixture and preparation method thereof

Info

Publication number: CN102728316A
Application number: CN2012102388351A
Authority: CN
Inventors: 张克金; 崔龙; 荣常如; 米新艳; 张苡铭; 张喆; 魏晓川; 刘国军
Original assignee: FAW Group Corp
Current assignee: FAW Group Corp
Priority date: 2012-07-11
Filing date: 2012-07-11
Publication date: 2012-10-17
Anticipated expiration: 2032-07-11
Also published as: CN102728316B

Abstract

The invention relates to a magnesium-salt ammonia storage mixture and a preparation method thereof. The preparation method is characterized by taking industrial anhydrous magnesium chloride powder as a raw material and comprising the following steps of: adding an appropriate amount of clay, expanded graphite, deionized water and industrial alcohol into the industrial anhydrous magnesium chloride powder; carrying out mechanical stirring on the obtained mixture so as to obtain a half-dry uniformly-mixed wet material; and filling the wet material into a tank body so as to prepare an integral porous solid block. Because rich ammonia gas transmission channels are distributed in the solid block, the solid block macroscopically has a plurality of large holes, so that the solid block has a rapid ammonia gas charging property and a better ammonia gas storage property, can release ammonia gas quickly, can be recycled and not broken, and has efficient adsorption and desorption characteristics, therefore, the solid block is suitable for the adsorption and storage of ammonia gas, and can be applied to SCR (silicon controlled rectifier) and FCEV (fuel cell electric vehicle) systems so as to meet the application requirements of the future automotive industry.

Description

A kind of storage ammonia mixture and preparation of magnesium salts

Technical field

The present invention relates to a kind of storage ammonia mixture and preparation of magnesium salts, be applied to the SCR after-treatment system and the FCEV fuel cell system of vehicle exhaust.

Background technology

Current, the whole world faces the comprehensive challenge of the energy and environment.Aspect the technological means selection of the emission compliance of orthodox car, and the fuel of new-energy automobile is supplied with the technical elements people and is still faced many difficult problems.

The SCR after-treatment system is to rely on the accurate supply of carbamide reducing agent and after the front end of catalyst resolves into ammonia, remove the NOX hazardous material; Reach the purpose of cleaning of off-gas; Realize state 4 or above standard up to standard of vehicle; But; In actual use, this dependence urea decomposition becomes the metered injection of the liquid area of ammonia to have many deficiencies and difficult point, for example; Urea liquid is icing blocking problem under-11 ℃ of environment, needs extra pipeline heating system to solve; Urea liquid could decompose under the temperature environment more than 135 ℃; And many vehicles of public transit system loiter; Can't reach urea liquid stable decomposition temperature at all; Can't the output ammonia; Can't eliminate predetermined NOX composition; Cause the accumulation of liquid area in blast pipe at last; Produce the polymer of melamine; Stop up the urea nozzle and the exhaust pipe of engine; Cause vehicles produces fault; Influence is normal to be used, in addition, if the main flow vehicle of state more than 4 uses the SCR system comprehensively; Relate to the whole nation about 150,000 oiling websites innovation and build the problem of liquid area filling infrastructure; Because investment is huge, do not see still that at present government and enterprise start to improve this infrastructure, become a potential huge problem in the SCR use;

For breaking through energy predicament, solve the new-energy automobile development problem of future source of energy problem, hydrogen fuel cell is a very important techniques route by generally acknowledging; But how stable acquisition hydrogen is originated is a no small difficult problem of restriction this area development, in institute's possible adopted hydrogen source mode; Technology path and the hydrogeneous presoma decomposition of other H-N or the technology path of cracking hydrogen production that the technology path of gas cylinder storage hydrogen, the technology path that water electrolysis hydrogen production is arranged, the technology path that high-purity hydro carbons petroleum fuel cracking hydrogen production is arranged, low mass molecule alcohol class cracking hydrogen production are arranged; In the above-mentioned technology path, all there are some problem and shortage, for example; Hydrogen production efficiency and cost; Hydrogen manufacturing precision and speed also comprise the problem of system aspects, in a word; The source of hydrogen is the bottleneck of fuel-cell vehicle development, needs people's idea to solve;

One of them is the hydrogeneous compound of H-N for the presoma of hydrogen, and wherein, what hydrogen-storage density was the highest is ammonia.Ammonia is a kind of modal industrial chemicals, and the ammonia molecule belongs to active polar molecule, and the diameter dimension of molecule is about 3 ~ 4A, therefore, very active under the normal temperature, very easily diffusion, and have toxic; The skin histology that its toxic is embodied in contact all has corrosion and spread effect, can absorb the moisture in the skin histology, makes the histone sex change, and makes the tissue fat saponification, destroys membrane structure; Ammonia in water solubility high, stimulate and corrosiveness so mainly the upper respiratory tract of animal or human's body is had, often be attracted on mucocutaneous and the eye conjunctiva; Stimulate and inflammation thereby produce, in addition, ammonia sucks human body with gas form usually; Ammonia gets into blood through alveolar after being inhaled into lung easily, combines with hemoglobin, destroys fortune oxygen function; Get into IA ammonia; Few part is neutralized by carbon dioxide, and remainder is absorbed into blood, suck in a short time can occur shedding tears behind a large amount of ammonias, pharyngalgia, cough, uncomfortable in chest, expiratory dyspnea, dizziness, vomiting, weak etc.; If the long-term ammonia that sucks is too much, cause ammonia excessive concentration in the blood, will cause heart stop fight and breath stopped threat to life safety; Therefore, the maximum hidden danger of the use of ammonia is safety problem.

This shows, resolve in the use of ammonia storing and safety problem, just can open up the technology path of a new ammonia utilization.

Traditional ammonia storing mode is a gas cylinder, or realizes with the water-soluble formation ammoniacal liquor of high concentration ammonia.If adopt gas cylinder to store ammonia, there is the potential safety hazard of operating aspect and seal aspect in the commercial Application in enormous quantities, if, have serious etching problem again with the mode of high concentrated ammonia liquor.

At China national patent information net; With the storage ammonia word and search that is the theme; The patent No. is that CN201120099229.7's ' a kind of urotropine by using gas phase method tail gas ammonia recovery unit ', the patent No. is that ' be used for freezer machine room join ammonia bindiny mechanism ' of CN201020677361.7, ' complex function type storage ammonia device ', the patent No. that the patent No. is CN201020269811.9 are CN200520057558.X ' a kind of ammonia steaming device '; Be one type the ammonia nitrogen industrial wastewater carried out the environment protection treating device that ammonia nitrogen is got rid of processing, also do not relate to the characteristic component among the present invention.Uncorrelated with the present invention;

The patent No. is that CN201010244091.5's ' be used for method and system that the work of SCR catalyst is tested ' and the patent No. is that this 2 inventions of CN200880104697.X ' operation method of SCR exhaust after treatment system and diagnostic method ' provide a kind of SCR (SCR) catalytic converter and traditional liquid ureaclastic ammonia dispensing module and control system of being used for, and does not relate to the characteristic component of compound;

The patent No. is that CN200910197860.8's the invention of ' a kind of preparation method of efficient low-temperature ammonia-storing material ' is applied to the SCR after-treatment system; Characteristic is to place closed container to the amino borane compound; Vacuumize, under 0-4 ℃ of temperature, contact with ammonia; Under 0-4 ℃ of temperature, kept 30-60 minute, prepare required product amino borane ammino-complex NH3BH3 (NH3) n (n=1-3); The maximum storage of room temperature ammonia amount can reach 62.4wt.%; About room temperature supply gas pressure 2.0bar; Room temperature supplies ammonia pressure moderate, inhales to put the ammonia completely reversibility, but the costing an arm and a leg of the extraordinary material amino borane of this patent; Have higher explosion danger and burning grade, be not suitable for applying in enormous quantities of general industry field;

The patent No. is that CN200580026626.9's the invention of ' storage and carry the solid material of ammonia ' relates to storage and carries the solid material of ammonia.The solid material of this storage ammonia comprises that a kind of ammonia absorbs salt, and wherein this ammonia absorption salt is that general formula is M _a(NH ₃) _nX _zIonic salt; Wherein M is selected from for example one or more cations of Mn, Fe, Co, Ni, Cu and/or Zn of alkaline-earth metal and/or one or more transition metal, and X is one or more anion, and a is the cation number that comprises in each molecules of salt; Z is the anion number that comprises in each molecules of salt; N is 2～12 ligancy, and wherein M is Mg, and it is auto industry that this ammonia absorbs salt provides a kind of safety, lightweight, cheap and fine and close storage with ammonia.This patent is the direct compression molding of solid material, and ammonia is resolved in the electric heating heating, more lays particular emphasis on the control strategy of system, does not relate to the modification and the optimization of mixture;

The patent No. be CN200580009219.7's ' purposes of ammonia storage device in energy production ' invention relate to a kind of generator unit, this unit comprises the ammonia storage device of (i) container (2) form, comprising general formula is M _a(NH ₃) _NXzAmmonia absorb and discharge salt; Wherein M is one or more cations, is selected from alkali metal, alkaline-earth metal and transition metal such as Li, K, Mg, Ca, V, Cr, Mn, Fe, Co, Ni, Cu or Zn, and X is one or more anion; Be selected from fluorine root, chlorine root, bromine root, iodine root, nitrate anion, thiocyanate radical, sulfate radical, molybdate, phosphate radical and chloranion; A is the cation number of each molecules of salt, and z is the anion number of each molecules of salt, and n is the ligancy of 2-12; (ii) being used to heat said container (2) and ammonia absorbs and discharges the fuel cell that salt with the device (3a) that discharges ammonia and (iiia) is used for ammonia is converted into electrical power; Perhaps (iiib1) is used for ammonia is dissociated into the reactor (6) of hydrogen and nitrogen; (iiib2) be used for hydrogen is converted into the fuel cell (4) of electrical power; This patent is mainly used in fuel cell; Mentioned property material in the claim 4 and be such salt or be positioned on the porous carrier materials, which kind of material statement is not;

The disclosure of the Invention of CN200710156866.1 ' a kind of amido complex compound ' a kind of amido complex compound.The composition of this amido complex compound is MX _m(NH ₃) _n, M is one or more among Li, Mg, Al, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Ba, the Sn in the formula; X is F, Cl, Br, NO ₃, SO ₄In one or more; M decides according to chemical valence, 1≤m≤5; N decides according to ligancy, 1≤n≤15.With the absorbent of the amido complex compound behind the deamination, put separation, purification, storage and the transportation that ammonia is realized ammonia through low temperature suction ammonia, high temperature as ammonia.This patent only relates to the preparation technology and the process of this amido complex compound itself;

The patent No. is solid ammonia storage and the conveying material that CN200680005886.2's the high density of the ammonia ' storage ' patent comprises ammonia absorptions/desorb solid material; The said density that has been compacted to is greater than 50% storage of theoretical skeletal density with carry material that the solid ammonia storage medium is provided; The storage ammonia that this storage medium prepares and handles and have very high-density easily; Said storage ammonia discharges under controlled condition easily; Even the porosity of said material is very low still like this, and this storage medium does not need special safety measure for storage with to carry ammonia be safe.This patent is to adopt the direct compression molding of solid material; Adopt binding agent; Only stated it possibly is the silicon dioxide fibre binding agent, do not had the dosage ratio, the solid material of also only stating among other claim item and the embodiment possibly comprise granular materials, porous material, crystalline material, amorphous materials or their bond composition; Do not have thin of clear and definite claim, industry technology personage almost can't implement.Produced the present invention therefrom.

Summary of the invention

The object of the present invention is to provide a kind of magnesium salts storage ammonia active mixture preparation, in order to improve the hole of storage ammonia active material solid block, increase the ammonia transmission channel, weaken or avoid adsorbing repeatedly with desorption process in MgCl ₂The caking that takes place and the efflorescence of solid block are broken, and that satisfies industrial occasions repeatedly recycles requirement, possesses and fills ammonia faster and store up the ammonia performance preferably; Can discharge ammonia fast; Can recycle not brokenly, possess efficient absorption and conciliate characterization of adsorption, the absorption that is fit to ammonia stores; Be used for SCR and FCEV system, satisfy the application demand of following auto industry.

Technical scheme of the present invention be achieved in that a kind of magnesium salts storage ammonia active mixture; It is characterized in that: press the powder of mass fraction by 45 ~ 92 parts industrial anhydrous chlorination magnesium salts; Mix 1 ~ 15 part industrial clay, 2 ~ 8 parts of expanded graphites, mix with 3 ~ 17 parts deionized water and 2 ~ 15 parts industrial alcohol.

Described preparation process of mixture is following: with the powder of the anhydrous chlorination magnesium salts of industry; Mix an amount of clay, expanded graphite, deionized water and industrial alcohol; Become uniform mixture wet feed through mechanical agitation; Be filled in the tank body, addition is no more than 80% of tank body volume, and machinery concussion 5 ~ 10min eliminates the air gap; Whole tank body is put in the vacuum drying oven, and normal pressure is slowly heating down, and temperature is controlled at 65 ~ 160 ℃; Get rid of water and ethanol to mixture constant weight, substep is evacuated to 550mbar, constant temperature and pressure 0.5 ~ 3h; Take out tank body, the sealing charge door is processed the whole porosu solid piece of storage ammonia active mixture; Ammonia fills in the tank body under 0.05 ~ 0.8MPa pressure, and is saturated to the mixture absorbing ammonia.

Described industrial ball clay particle diameter is less than 2um, and disperse becomes suspension in water.

The expansion multiplying power of described expanded graphite is 250～380ml/g, particle diameter≤15um.

Good effect of the present invention is optionally to have added expanded graphite, and the expansion multiplying power here is 250～380ml/g, particle diameter≤15um.The graphite plane layer that expanded graphite is is polygon or slit shape and corresponding parallel cinclides or wedge hole; Make expanded graphite have good compression resilience; And less thermal coefficient of expansion; For magnesium chloride amasss expansion and dwindles the space that provides enough in absorption and desorb procedure body, guaranteed that the performance of mixture can not change.High porosity makes that gas can be easy to adsorb and desorption through abundant pore structure, and expanded graphite has promoted MgCl ₂Dispersion; Can weaken or avoid the generation of caking phenomenon effectively, improve the richness of microscopic void, increase the transmission channel of ammonia; Improve the permeance property of ammonia greatly; Promote the formation of ammino magnesium chloride complex compound, the loose structure of expanded graphite itself possesses certain absorption and memory function to ammonia simultaneously; The particle diameter that adds is less than the industrial ball clay of 2um, and disperse becomes suspension in water, by means of mechanical agitation and MgCl ₂Reach other fillers and fully mix, at MgCl ₂Bridging between the particle, dry back forms higher " the integrated solid piece " of mechanical strength, can weaken effectively or avoid adsorbing with desorption process in the expansion of solid block to shrink the efflorescence that causes broken; The diffusing MgCl of water that adds and dissolve with ethanol and differential ₂And other fillers, improve between the liquid-solid two-phase wetting with sprawl, in addition, water and ethanol are deviate from the hole of process formation, have enriched the transmission channel of ammonia; Used tank body is the withstand voltage tank body of stainless steel, inner tank wall thermal spraying nylon heat-insulation layer.

To sum up; Guaranteeing under the constant prerequisite of storage ammonia active material characteristic that the clay of interpolation and expanded graphite weaken or eliminated the phenomenon that ammonia adsorption-desorption that caking, expansion fragmentation etc. cause attaches, improving the richness of microscopic void; Increased the quantity of macroscopic pores; Improve the mechanical strength of composition appearance piece, had very high practical value, be suitable for the SCR post processing or the FCEV system of automobile industry.

Description of drawings

The thermogravimetric curve of the active mixture of the absorbing ammonia of Fig. 1 embodiment of the invention 1.

The specific embodiment

Through embodiment the present invention is further described below, embodiment is not equal to restriction the present invention for further illustrating characteristics of the present invention,, all should be included within protection scope of the present invention according to the change that the present invention carries out for those skilled in the art.

Embodiment 1

Water with 71 parts magnesium chlorides, 3 parts of expanded graphites, 6 parts of industrial ball clays and 12 parts; In homogenizer, mix 1h; Add 8 parts of ethanol; Continue mechanical agitation 3h; Make uniform mixture wet feed; Be filled in the tank body, be added into 80% of tank body volume, machinery concussion 10min eliminates the air gap;

Whole tank body is put in the vacuum drying oven, and the heating rate with 2 ℃/min under the normal pressure as shown in Figure 1 rises to 120 ℃, constant temperature 6h; Get rid of water and ethanol, substep is evacuated to 550mbar, constant temperature and pressure 1h; Take out tank body, the sealing charge door is processed the whole porosu solid piece of storage ammonia active mixture.

Embodiment 2

Water with 2 parts of expanded graphites, 15 parts of industrial ball clays and 15 parts; In homogenizer, mix 1h; The magnesium chloride mixing 1h that adds 58 parts; Add 10 parts of ethanol; Continue mechanical agitation 3h, make uniform mixture wet feed, be filled in the tank body; Be added into 75% of tank body volume, machinery concussion 10min eliminates the air gap;

Whole tank body is put in the vacuum drying oven, and the heating rate with 2 ℃/min under the normal pressure rises to 120 ℃, constant temperature 6h; Get rid of water and ethanol, substep is evacuated to 550mbar, constant temperature and pressure 1h; Take out tank body, the sealing charge door is processed the whole porosu solid piece of storage ammonia active mixture.

Embodiment 3

Water with 5 parts of industrial ball clays and 6 parts; In homogenizer, mix 1h; The magnesium chloride mixing 1h that adds 80 parts; Add 3 parts of expanded graphite mixing 1h, add 6 parts of ethanol, continue mechanical agitation 3h; Make uniform mixture wet feed; Be filled in the tank body, be added into 80% of tank body volume, machinery concussion 10min eliminates the air gap;

Whole tank body is put in the vacuum drying oven, and the heating rate with 5 ℃/min under the normal pressure rises to 100 ℃, constant temperature 8h; Get rid of water and ethanol, substep is evacuated to 550mbar, constant temperature and pressure 2h; Take out tank body, the sealing charge door is processed the whole porosu solid piece of storage ammonia active mixture.

Embodiment 4

The tank body that the storage ammonia active mixture of accomplishing for embodiment 1 installs additional adopts high-purity industrial ammonia bottle through subsequent use pipe valve, in the outlet pressure scope of 0.4Mpa slowly fill ammonia, filling the ammonia time is 3h, fill ammonia before and after the tank body quality increase by 40%;

The tank body that completion is filled behind the ammonia is connected with automobile SCR system, and under the situation of ammonia leakage rate less than 10ppm, quality reduces 34% before and after the test tank body desorption.

Embodiment 5

The tank body that the storage ammonia active mixture of accomplishing for embodiment 2 installs additional adopts high-purity industrial ammonia bottle through subsequent use pipe valve, in the outlet pressure scope of 0.2Mpa slowly fill ammonia, filling the ammonia time is 6h, fill ammonia before and after the tank body quality increase by 36%;

The tank body that completion is filled behind the ammonia is connected with automobile SCR system, and under the situation of ammonia leakage rate less than 10ppm, quality reduces 32% before and after the test tank body desorption.

Embodiment 6

The tank body that the storage ammonia active mixture of accomplishing for embodiment 3 installs additional adopts high-purity industrial ammonia bottle through subsequent use pipe valve, in the outlet pressure scope of 0.5Mpa slowly fill ammonia, filling the ammonia time is 5h, fill ammonia before and after the tank body quality increase by 42%;

The tank body that completion is filled behind the ammonia is connected with automobile SCR system, and under the situation of ammonia leakage rate less than 10ppm, quality reduces 36% before and after the test tank body desorption.

Claims

A magnesium salts storage ammonia active mixture; It is characterized in that: press the powder of mass fraction by 45 ~ 92 parts industrial anhydrous chlorination magnesium salts; Mix 1 ~ 15 part industrial clay, 2 ~ 8 parts of expanded graphites, mix with 3 ~ 17 parts deionized water and 2 ~ 15 parts industrial alcohol.
A kind of magnesium salts according to claim 1 storage ammonia active mixture; It is characterized in that described preparation process of mixture is following: with the powder of the anhydrous chlorination magnesium salts of industry; Mix an amount of clay, expanded graphite, deionized water and industrial alcohol, become uniform mixture wet feed, be filled in the tank body through mechanical agitation; Addition is no more than 80% of tank body volume, and machinery concussion 5 ~ 10min eliminates the air gap; Whole tank body is put in the vacuum drying oven, and normal pressure is slowly heating down, and temperature is controlled at 65 ~ 160 ℃; Get rid of water and ethanol to mixture constant weight, substep is evacuated to 550mbar, constant temperature and pressure 0.5 ~ 3h; Take out tank body, the sealing charge door is processed the whole porosu solid piece of storage ammonia active mixture; Ammonia fills in the tank body under 0.05 ~ 0.8MPa pressure, and is saturated to the mixture absorbing ammonia.
A kind of magnesium salts according to claim 1 storage ammonia active mixture, it is characterized in that described industrial ball clay particle diameter less than 2um, disperse becomes suspension in water.
A kind of magnesium salts according to claim 1 storage ammonia active mixture, the expansion multiplying power that it is characterized in that described expanded graphite is 250～380ml/g, particle diameter≤15um.