粉末活性炭与炭基粉末催化剂与液体的精密过滤英文版

粉末活性炭与炭基粉末催化剂与液体的精密过滤英文版

Abstract :The precise filtration of the powder active carbon and carbonyl powder catalysts from reaction liquid are chemical unit operations which are required widely in chemical and pharmaceutical manufactures . Because the filtrate qualities of these filtrating operations must be quite excellent , but these particles size of carbon powder is very small and penetrating to cake and media easily , resulting in “ leaking carbon ” becomes a difficult problem which is hard to avoid in above chemical operations . The features of these carbon powders would be described and the main progresses to solve these difficulties in last ten years by our company would be simply introduced .  

Key words :powder active carbon , carbonyl powder catalyst , precise filtration

Condensed version :

Powder active carbons are very excellent decolouring absorbent and carbonyl powder catalysts are powder catalysts with powerful catalyst function . More finer the carbon powder , more stronger the absorber and the catalyst function , but result to more difficult solid-liquid separation . In order to resolve this heavy difficulties , from early stage of this century , we are engaged in research works nearly ten years to contain all developments consist of filtering principle and laws for ultra-fine particles , new compositions of filtering media and new structures of precise cake filters etc. Some breakthrough progresses have been obtained , two thousand new precise cake filters used for powder active carbon have widely been applied in a large amount of pharmaceutical and fine chemical manufactures for a long time , two hundred new type precise cake filters of carbonyl powder catalyst have been applied in many pharmaceutical , fine chemical and farm chemical manufactures for a long time . Twenty new types of precise filters used to carbonyl powder catalyst with big diameter of 2.8m to 3.3m have been successfully applied in farm chemical factories .

1. Some characteristics in filtration of powder active carbon and carbonyl powder catalyst from liquid :

1.1 Ratio of the particle numbers of the sub-micron particles to all particles number of powder carbon particles are greater than 90%:

The powder carbon particles , either powder active carbon or carbonyl powder catalyst , although the sizes of the particles based on the volume are not very fine , but the sizes of the particles based on particles number are very fine . A powder active carbon with mark of 767 used for pharmaceutical manufacture the average size based on volume is 3.79μm , the 10% of all powder particles based on volume are less than 0.87μm , the 3% of all powder particles based on volume are less than    0.57 μm , nearly not fine , but the average size based on particles number is 0.17μm , the 3% of all powder particle numbers based on particles number are less than 0.0066μm , the 10% of all powder particles numbers based on particles number are less than 0.022μm, even though the 50% of all powder particles numbers based on particle number are also less than 0.056μm, or less than 56 nm . A carbonyl powder catalyst used for glyphosate manufacture , the average size based on volume is 2.92μm , the 10% of all particles based on volume are less than 0.46μm , nearly not fine , but the average size of particles based on particles number is 0.395μm , the 3% of all powder particles number are less than 0.1μm , the 10% of all powder particles number based on particles number are less than 0.12μm , even though the 50% of all powder particles number based on particles number are also less than 0.25μm . Above two powder carbons , the 90% of carbon particles number based on particles number are less than 1μm . These carbon powder particles should belong to sub-micron powers .

1.2 Fine particles of carbon powder penetrating easily through the capillary pores in cake and media :

The surface of carbon powder particles are no adsorbable water layer . The compressibility of these particles are very small , the cake consisting with above carbon powder particles are incompressible . The capillary pores in the cake and filtering media should be not less than 1μm. 90% of carbon powder particles are less than 1μm, therefore the particles of sub-micron , especially the particles of less than 0.5μm will certainly be penetrated through the capillary pores of cake and filtering media under pushing action of filtrate liquid , then easy result in “ leaking carbon ” to the filtrate liquid and blockage of filtering media .

1.3 Higher temperature of filtering operations result in “ leaking carbon ” and damaging media :

The temperature of filtering operation for the powder active carbon and carbonyl powder catalyst from liquid would be not less than 80~100℃, the viscosity and surface tension must be reduced , therefore, not only to increase “ leaking carbon ” , but also to enhance the damage velocities of filtering media by decolorising liquid or catalyst action liquid such as acids , alkalies , salts and organic solvents . 

2. New achievements in precise filtration technology :

2.1 New achievement of filtering media :

2.1.1 Microporous tubes of two meters with higher equilibrium in one finishing be a success : 

   Although the new filtering media such as microporous tubes of PE and PA have been produced for 40 and 30 years , but the length of a tube which can be finished only is one meter . If needing 1.5 or 2 meters , it would be adhered with hot melting , resulting to breaking in nearby adherent surface frequently .

The microporous PE tubes of two meters in one finish have been successfully produced in 2007 and the microporous PA tubes of two meters in one finish have been successfully produced in 2008. After measuring 18 samples cutting from one microporous PA tube of 2 m long, the fluctuating of the average pore sizes and the average porosities are about 5% . It indicates the quality of microporous PA is very outstanding . The manufactures of microporous PA tubes are more difficult than the PE tubes owing to very fine raw material of multicomponent mixture .

2.1.2 Large diameter microporous plates with ability resisting anti-pressures of 10 Kg/cm2have been successfully researched :

After research and development for 8 years , a large diameter microporous plates with ability resisting anti-pressure of 10 Kg/cm2have been successfully researched in 2008 , the maximum size of plate is 1.8×1.8 m .

Picture 1 is microporous plate ofΦ800 mm . It was making air bubbling under water with air of 10 Kg/cm2.  

Picture 2 is microporous plate of 1.8×1.8 m . These microporous plates have the ability of resisting anti-pressure of 10 Kg/cm2.    

       Picture 1                       Picture 2

2.1.3 The antioxidant ability of microporous filtering media obviously strengthen :

The microporous PE and PA can resist any acids , alkalies , and organic solvents , but cant resist strong oxidizer . The microporous PE and PA could be used for three month only under strong oxidizer (vigorous oxidation and vigorous chlorination ) . Now a new microporous PE and PA with new compositions have been applied for one year under strong oxidizer in same production site and same condition .

2.2 New achievements for constructions of precise filters:

2.2.1 Developing of constructions for large diameter bottom cover with quick opening :

2.2.1.1 Developing of constructions with multiple hooks for large diameter bottom cover with quick opening :

The construction with multiple hooks was developed by us in the beginning of this century , then a new precise filter with large diameter of 1.6~1.8 m bottom cover has been soon developed and has widely been used to filter powder active carbon and carbonyl powder catalyst .

Picture 3 are the appearance of filters with diameter of 1.6 m bottom cover provided with multiple hooks .

                 Picture 3

2.2.1.2 Developing of construction with rotating hooks for large diameter bottom cover with quick opening :

A new construction of quick opening bottom cover with 1.6 m provided rotating hooks has been successfully developed by us during 2008~2012 .

The new construction has good function of self-lock , operating conveniently , and a bottom cover with diameter of bigger than 2 m could easily be manufactured .

2.2.2 Developing of new constructions within precise filters :

Some new constructions within precise filters have uninterruptedly developed from 2000 , in order to wash the cake within precise filters efficiently and quickly , and to discharge the dry cake from precise filter conveniently , no requiring arduous labors .

Picture 4 is the new construction of bottom cover with horizontal arranging of filtering media .

Picture 5 is the appearance for new filter of carbonyl powder catalyst with no bottom cover .

3. Conclusion:

   The rigid polymer precise microporous filtration technologies are new filtering technologies of independent innovation which have been researched and developed for forty-six years . It has inherent advantages such as excellent filtering qualities , operating convenient , long use life , energy saving , materials saving , emission reduction . Owing to lack of full fund and basic conditions for research and development in earlier stage , leaving countless technical difficult problems must be continuously researched . In early of this century , in order to effectively resolve the filtration , washing and dewatering of powder active carbon and carbonyl powder catalyst due to urgency need from many production factories . We make development continuously for more than ten years . Some new major achievements in filtering media and constructions of precise filters finally have acquired . In this paper , some main progresses of filtering media and constructions of precise filters should be simply described .