Pellet temperature

Air from combustion chambers Maximum pellet temperature Gas discharge Pellet discharge... 

Approximately 25% of the total air is introduced through the combustion chambers and subsequently into the upper part of the column of pellets. Maximum pellet temperature is reached in the top 2 ft (0.6 m) of the stock column. 

In cases of multiplicity (that is more than one solution to Equation 4.10), of the three intersection points only those at the lowest and highest pellet temperature represent stable conditions. These are therefore called the stable operating points. The intermediate intersection point is referred to as an unstable operating point. 

Figure 4.4 Relative heat production and heat withdrawal rates versus dimensionless pellet temperature 0p A) exothermic reactions, 0p, 0t and An > 0 B) endothermic reactions, 0p, 0t and An < 0 ( ) stable operating point (o) unstable operating point.

Figure 4.6 Dimensionless pellet temperature 0p versus 0 for An -3 and 0, = 0.3. Note the hysteresis, runaway, and blowout.

Processing temperature K Samples density (q 10 kg/m ) at pelleting temperature, K ... 

Fig. 16. A chaotic front moving through a fixed-bed reactor during CO oxidation over Pt/ AljOj. Ta, Tk, Tc, and Tj are pellet temperatures in the entrance cross section T) and T2 are thermocouple temperatures 24 and 46 mm downstream, respectively. Chaos was characterized by correlation dimension and Liapunov exponent. (From Ref. 700.)...

The pellet temperature profile proceeds through the maximun during the... 

The pellet temperature equation for the multiphase gas-solid mixture can be expressed as ... 

The pellet temperature equation considering the multiphase gas-solid mixture was expressed on the form (11.29). 

Mathematically, the dynamic behaviour of the system is represented by ordinary differential equations in the state variables which are pellet temperature and concentration of reactants (and products in certain cases), with time as the independent variable. This is in contrast to the more realistic distributed models which account for intraparticle temperature and concentration gradients. 

Equation (5.54) can be used for a first estimate of (T, — Tg), but since k and Y] depend on the average pellet temperature and since is lower than the bulk concentration C, a trial-and-error solution would be needed for exact values of and A simpler equation to show the relative values of and is obtained by relating Q to the rate of mass transfer to the surface and the heat of reaction ... 

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