Pellet density

A practical method of prepg this compn was by the addition of a soln of the coating agent to an aq RDX slurry. Based on the quality of the product and the pellet densities obtained, a procedure of adding an acet soln of PVA + DBP to a hot w slurry of RDX, under agitation, was adopted as standard... 

Sample BET sur ce area(m2g-l) Pore volume Micropore volume (cm3g-l) (cm3g-l) Average pore diameter (nm) Pellet density (gcm-3)... 

Pellet density Void volume gram Specific surface area Enthalpy change for reaction Temperature Total pressure... 

The physical properties of the catalyst (specific surface area, porosity, effective thermal conductivity, effective diffusivity, pellet density, etc.). 

Thiophene (C4H4S) is representative of the organic sulfur compounds that are hydrogenated in the commercial hyditodesulfurization of petroleum naphtha. Estimate both the combined and effective diflfusivities for thiophene in hydrogen at 660 °K and 3.04 MPa in a catalyst with a BET surface area of 168 m2/g, a porosity of 0.40, and an apparent pellet density of 1.40 g/cm3. A narrow pore sized distribution... 

Pore volume, 0.48 cm3/g Surface area, 240 m2/g Pellet density, 1.332 g/cm3 Pellet porosity, 0.59 cm3 voids/cm3... 

Field in 1.6 ha enclosures on hunted or nonhunted wetlands California 1986-89 lead shot pellet density in enclosures were 15,750, 173,200, or >2 million/ha Blood lead concentrations increased, and survival reduced with increasing shot density 39... 

Assuming uniform cylindrical pores, the radius is expressed in terms of the pellet density pp, the specific surface Sp and porosity c. This converts the equation to... 

Figure 2.1 Influence of pellet density on black powder burning time.

The way in which experimental parameters are affected when intraparticle diffusion is dominant may be deduced by inspection of eqn. (14). Referring the specific rate constant to unit area, rather than unit volume, k becomes where Pp is the pellet density, Sg the surface zirea... 

Wheeler [16] proposed that the mean radius, r, and length, L, of pores in a catalyst pellet (of, for that matter, a porous solid reactant) are determined in such a way that the sum of the surface areas of all the pores constituting the honeycomb of pores is equal to the BET (Brunauer, Emmett and Teller [17]) surface area and that the sum of the pore volume is equed to the experimental pore volume. If represents the external surface area of the porous particle (e.g. as determined for cracking catalysts be sedimentation [18]) and there are n pores per unit external area, the pore volume contained by nSx cylindrically shaped pores is nSx nr L. The total extent of the experimentally measured pore volume will be equal to the product of the pellet volume, Vp, the pellet density, Pp, and the specific pore volume, v. Equating the experimental pore volume to the pore volume of the model... 

Variations in density reflect variations in dimensions with those of the bulk density and flow characteristics of the expl, and those of the measured volume. With frequent pellet density determinations and occasional adjustment of the pelleting press, expls with good flow properties can be pressed into pellets reproducible in density to 1% in an automatic pelleting press... 

Name Composition %Ni Surface Area m2/g Pellet density kg/m3 Porosity... 

In a series of experimental studies Munir and co-workers18-21 examined the combustion of titanium pellets in nitrogen. Using thermogravimetric measurements they demonstrated the significant contribution of afterburning on the total conversion. They studied the effect of pellet density and solid phase dilution on the final conversion, but the range of pressures examined was only between 1 and 14 bar. 

Example 10.9 used two different definitions of the catalyst density and at least two more definitions are in common usage. The value pc = 367 refers to the reactor average density. It is quite low in the example because so much of the reactor volume is empty. Normally, the reactor would be packed almost completely, and the reactor average density would approach the bulk density. The bulk density is what would be measured if the catalyst were dumped into a large container and gently shaken. The bulk density is not stated in the example, but it would be about 800 kg/m3 for the catalyst pellets prior to grinding. The catalyst will pack to something less than the bulk density in a small-diameter tube. The pellet density in the example is 1120 kg/m3. It is the mass of a catalyst pellet divided by the external volume of the pellet. The final density is the skeletal density of the pellet. It is the density of the solid support and equals 1120/(1 — 0.505) = 2260 kg/m3 for the example catalyst. The various densities fall in the order... 

The pellets are then delivered in bulk by lorry, train or boat and also in large or small sacks to consumers. Pellets are burned in pellet furnaces to produce heat in small-, medium- and large-scale facilities. Since the quality of pellets may vary during production there are some parameters that can be used to evaluate this. The most important physical parameters are bulk density, pellet density, durability, which can be measured by determining the amount of fines, and particle size distribution of the raw material. Chemical parameters include pellet moisture content, calorific heat value as a determinant of energy content, element content (such as K, Mg, Ca, N, S, Cl), ash content and ash melting behaviour in order to prevent the agglomeration of the ash in the furnace. The net calorific heat value of pellets is about 19 MJ kg-1, which is less than 50% of the oil equivalent. Pellets consist... 

Pellet density pp 1.332 g cm Pellet Porosity = 0.59 Effectiveness factor 17 — 0.42... 

Table 4.1 Pellet Density Versus Loading Pressure"...

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