Cooling air rates

Tower size Prill tube height, ft Rectangular cross section, ft Cooling air rate, Ib/h inlet temperature temperature rise.°F Melt Type Urea 130 11 by 21.4 360,000 ambient 15 Ammonium Nitrate... 

Drying air temperatures — 350°C Drying air rate — 166 /h Atomizing air temperature — 340°C Atomizing air rate — 72 /h Nozzle cooling air rate — 15 /h Quench air rate — 140 /h... 

In process engineering terms the planetary cooler functions on the same principle as the rotary cooler. The cooling air rate corresponds to the secondary air supplied to the kiln. The air flow through the cooler is sustained by the kiln exit gas fan. 

With planetary, rotary and shaft coolers the fluctuating rate of clinker discharge from the kiln due to ring formation and coating movements causes high and markedly varying final clinker temperatures, since the radiation heat losses remain substantially constant and the cooling air rate available to these coolers can practically not be altered. 

In the main, the variables which are measured and recorded are temperatures, pressures, flow rates and rotational speeds, comprising more particularly secondary air temperature exhaust air temperature clinker exit temperature temperature of grate plates pressure in kiln hood undergrate pressures reciprocating grate movement cooling air rates. 

Inductor. The channel inductor assembly consists of a steel box or case that contains the inductor refractory and the inductor core and coil assembly. The channel is formed within the refractory. Inductor power ratings range from 25 kilowatts for low temperature metals to 5000 kilowatts for molten iron. Forced air is used to cool the lower power inductors, and water is generally used to cool inductors rated 500 kilowatts or more. 

For large motors, which use water as the secondary coolant in a closed circuit, the temperature of the cooling air, i.e. of the primary coolant, varies with the temperature of the cooling water inlet temperature and its rate of flow. For the performance of the motor output, this primary coolant, temperature has the same significance as the ambient temperature for an air-cooled motor. The motor output is unaffected by the ambient temperature. For such motors the output graph is shown in Figure 1.13 at different coolant temperatures and altitudes. The rating at 25°C inlet water temperature for water-cooled machines is the same as for air-cooled machines at an ambient temperature of 40°C. 

For motors with a short-time rating, the duration of the test should correspond to the specified short-time rating. At the end of the test the specified temperature rise limits should not exceed. At the beginning of the test, the temperature of the motor should be within 5°C of that of the cooling air. 

The theoretical steam rate (sometimes referred to as the water rate) for stream turbines can be determined from Keenan and Keyes or Mollier charts following a constant entropy path. The theoretical steam rate is given as Ib/hr/kw which is easily converted to Ib/hr/hp. One word of caution—in using Keenan and Keyes, steam pressures are given in PSIG. Sea level is the basis. For low steam pressures at high altitudes appropriate coirections must be made. See the section on Pressure Drop Air-Cooled Air Side Heat Exchangers, in this handbook, for the equation to correct atmospheric pressure for altitude. 

Calculate the new Ga, assuming that L is the important value known. If on the other hand, it is desired to determine just how much cooling can be obtained, then for a fixed air rate, calculate the L that can be accommodated. 

Thermal shocking—reduce feed in 20% increments while maintaining maximum air rate to the regenerator. Cool the expander inlet temperature to around 1,000°F (540°C) and hold for at least one hour. This is not a procedure that the expander vendor supports, but it is practiced by many refiners. 

Consider an experiment in which an air-cooled device is being tested and it is desired to determine the rate of heat transfer Q to the cooling air (ASME 2000). This can be accomplished by measuring the mass flow rate m, and the inlet and outlet air temperatures, Tin and Tout, and computing ... 

Air from the compressor is split into two streams primary air is premixed with the fuel and then fed to the catalyst, which is operated under O2 defect conditions secondary air is used first as a catalyst cooling stream and then mixed with the partially converted stream from the catalyst in a downstream homogeneous section where ignition of gas-phase combustion occurs and complete fuel burnout is readily achieved. The control of the catalyst temperature below 1000 Cis achieved by means of O2 starvation to the catalyst surface, which leads to the release of reaction heat controlled by the mass transfer rate of O2 in the fuel-rich stream and of backside cooling of the catalyst with secondary air. To handle both processes, a catalyst/heat exchanger module has been developed, which consists of a bundle of small tubes externally coated with an active catalyst layer, with cooling air and fuel-rich stream flowing in the tube and in the shell side, respectively [24]. 

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