Determination of the true density and apparent molecular sieve catalyst density

Determination of true density, commonly used nitrogen replacement method in a vacuum adsorption capacity device. Atmosphere can enter all the pores of the sample itself is rarely to be adsorbed, without chemical change, is the ideal replacement media. If nitrogen is not readily available, nor require very strict, the organic liquid or water may be used in place of benzene, isopropanol and the like. These alternative molecular substances can only allow them to enter the cross section of a molecule into the pores, but can not enter all the pores of the sample, so had an approximate density side is the matrix density, i.e., apparent density Pa.
Isopropyl drunk fluidized catalyst for dehydration of ethanol replacement method is more commonly used measurement method Pa. This method has been recommended Weld density bottle and a feeding device with a capillary stopper. Pre-test sample with water and isopropyl alcohol in the side of the density of a given temperature correction ju bottles. After the sample is added to the density of the bottle, said the quality of the sample, and then pull the plug capillary tube. The density of the bottle mouth set in the ground on the charging device following grinding mouth tube, evacuated, while adding isopropyl drunk part in a test tube feeding device. When the pressure is less than the sample Ou on "133. 322P. When the rotary piston, so slowly adding isopropanol sample, then put the new capillary density injustice bottle stopper, at a given temperature side after weighing balance. According to these mass and temperature of the water at the side of a given density,
Hue grain density meter is filled with mercury, although the determination of the appropriate, measured before first checking for leaks glass piston. After the first six piston pump is turned on, open the piston 4 is evacuated for some time, with 7 mercury pressure gauge to check the connection of the piston vacuum. Once confirmed the formation of a vacuum, and then close the piston 4 and 7. 6 rotary piston slowly into the atmosphere after the pump stops. Slowly open space filled with mercury piston 3 2, closed when the mercury rose to the surface of the piston 4 position 3, this time on the left to read the calibration tube demand side of the piston Liu, set V1 (MI.), And then put through the piston 4 into the atmosphere. Open the piston 3, so that the mercury level drops. When the lid 5 open mill, into the weighed sample grain sheet, as before re-operation. Read volume V3 (mL), mercury surface down to the proper position, the piston 3 to close and open the cover 5 day wear, Samples were taken with a teaspoon.

Factors affecting the molecular sieve catalyst Hang crushing strength

Jing and zeolite catalytic factors affect the mechanical strength of the lot. Their chemical composition determines the aggregate or cohesion within the crystal, i.e. tensile strength. It is the inherent strength of the product. Usually there is a rough relationship between the inorganic solids usually strength and hardness to their melting point. A low melting point with the body has a low strength and hardness, and high melting point by its high hardness and strength.
First, the product prepared by a different mountain. Surface contact points produce a different space structure, defects and grain powder room, etc. whip, which naturally also affect its mechanical strength.
Second. The mechanical strength of the product will occur in use changes, such as the reaction was adsorbed on the solid surface. Generally reduces its mechanical strength, which is - during the reaction to promote the catalytic cracking Xia Jing and ethanol dehydration molecular sieve to Factors. Further use of the time and temperature will affect its mechanical strength.
Hang crushing strength in the industry and the size of the zeolite catalytic Jing direct impact on their effectiveness in working conditions and life. If Hang crush strength is too small. It may break or powdering during use, which not only shortens the molecular cry, catalyst life. But also lead to uneven distribution of sulfur donors, blocking game system to increase bed resistance, Estrogen can cause severe security risk and even forced to stop.

molecular sieve ethanol dehydration

Zeolite catalyst density analysis

(1) Bulk density Bulk
Test Method This bulk density is in a container, by free-fall section exposed to the air for 24h the bulk density of the sample.
This method takes the instrument may be a simple cylinder for a tap or bulk density of the analyzer.
(2) tapped bulk density
Determination of tapped bulk density of conventional vibration method, using the experimental apparatus shown in ASTM standard specified in FIG. 3-7, the test method is the pretreatment of the catalyst at 400 ℃ 3h in air (reduction catalyst should be in an inert atmosphere be). After cooling, the operation of the vibrator in the measuring device to the second 2 ^ -3m1. rate added through the feed hopper into the measuring cylinder, and then continue the vibration lmin, shutting down the vibrator, amount of catalyst volume and weighed mass, calculated tap bulk density.
Calculated with the formula without standard equipment in the laboratory, can be used in the rubber board 250mL graduated cylinder side edge joined to make a real sample, to be added to complete the sample continues to trample real 2min. This method measured the non-strict measure bulk density.

Anti-crush strength of the catalyst and molecular sieve methods

Because of different shape and molecular sieve drying, different stress points, said the crush strength of the ways are different. Usually divided into axial (or normal phase) Crushing strength (N / cm2), radial (or lateral phase) Crushing strength (N / cm) and the point Crushing strength (N /%). Where the former surface contact. The latter two are in line contact and point contact, respectively mouth (axis) ,. (Diameter) and. (Dot) said. Strip, ring, shaped spokes reminder
Agents and molecular sieve xh-7 with radial crush strength is represented by dots and spherical crush strength is expressed.
Catalytic Jing large particle size or carrier, such as Raschig rings, a spherical molecular sieve, the board side of the test method can be used to mean value. Small particle size catalyst, is preferably used stacking strength meter, deep extent stacked on top of a volume of the sample under pressure chipping 'as the catalyst for the fine particles, the average number of single V Hang crush strength of the catalyst is not important. Sometimes probably a few percent of the crushing pressure will cause a surge in the catalyst bed was forced to stop.

Jing zeolite catalysis and adsorption properties of packaging materials and moisture

Jing and zeolite catalysis is a porous material. Some types of finely powdered products or very fine. Therefore they have a large surface area thereof. The internal surface of the atom atom in a different state, the internal atomic attraction uniformly distributed in the circumferential country atom force field to make the saturation equilibrium, while the surface atoms of this force field is not saturated, That surface adsorption force field exists, there is the surface energy. When the gas or liquid molecules into the force field range, it will be adsorbed, thereby reducing the surface energy by the white system. This unsaturated force field scope. Roughly equivalent to the size of the molecular diameter. That is about a few angstroms. Therefore, they have a very clear its adsorption performance is good adsorption Jing.
Depending on the size of adsorption. Adsorption phenomena generally classified into two types of physical adsorption and chemisorption. Physical adsorption force is van der Waals forces. Therefore, similar to the adsorption heat and condensation heat, and the adsorption is reversible adsorption is fast, a greater speed at low temperatures. Chemisorption between the adsorption and chemisorption Jing success key role. Adsorption heat large (> 10kcal / mol, lea [. A 1840J). And the chemical reaction heat is similar but different chemical adsorption and chemical reaction. No new material is generated. Chemical adsorption is irreversible, and must have a high activation force dish surface can be overcome.
Which adsorb moisture in the air is the most common physical adsorption phenomenon. Such as zeolites have play very absorbent sheets can, even at very low partial pressure or concentration. There is still a very high adsorption capacity bi, so no matter what is used. Can get a good depth of dry operation. Or zeolite 3a molecular sieve for ethanol drying catalyst during the activation. Can not completely remove the moisture contained therein, but also more or less finished product prior to packaging certain adsorbed moisture, the moisture of the total sub-Jing or Automobile Desiccation Molecular Sieve catalyst and a percentage of this substance is said to Lang moisture for most packaged goods, usually expressed as a mass fraction II.