Internal heating

Germany, Bitterfeld 1920 two-stage rotary kilns heated internally using intermediate grinding of roast oxidation completed within 3—4 h cylindrical monopolar ceUs, 4 m volume undivided con-centric Ni anodes, rod-shaped Fe cathodes unfiltered electrolyte batch operation KMnO crystallizes in ceU electrolysis energy consumption about 700 kWh/1 4,000 27,113... 

A urea melt is suppHed to a one-stage reactor containing a fluid-bed catalyst. The reactor is heated internally by circulating molten salt. Upon entering the reactor, the urea is converted to melamine by the hot catalyst. 

Commercial dryers differ fundamentally by the methods of heat transfer employed (see classification of diyers, Fig. 12-45). These industrial-diyer operations may utihze heat transfer by convection, conduction, radiation, or a combination of these. In each case, however, heat must flow to the outer surface and then into the interior of the solid. The single exception is dielectric and microwave diying, in which high-frequency electricity generates heat internally and produces a high temperature within the material and on its surface. 

BATCH HEATING INTERNAL COIL, ISOTHERMAL HEATING MEDIUM... 

Batch heating internal coil isothermal heating... 

When complexes of bulky tertiary phosphines are heated, internal metal-carbon bond formation frequently occurs (Figure 3.50). 

Ozgener O., Hepbasli A. (2005). Experimental investigation of the performance of a solar-assisted ground-source heat pump system for greenhouse heating. International Journal of Energy Research, 29(3), 217-231. 

Isothermal a system condition in which the temperature remains constant this implies that heat internally generated or absorbed is quickly compensated for by sufficient heat exchange with the surroundings of the system. 

Orhan, M., I. Dincer, M.A. Rosen (2008), Energy and Exergy Assessments of the Hydrogen Production Step of a Copper-chlorine Cycle Driven by Nuclear-based Heat , International Journal of Hydrogen Energy,... 

Li, C., and Dickie, R. A., Bonding Adhesive Joints with Radio Frequency Dielectric Heating, International Journal of Adhesion and Adhesives, vol. 11, no. 4, October 1991, pp. 241—246. 

A plane wall 6.0 cm thick generates heat internally at the rate of 0.3 MW/m3. One side of the wall is insulated, and the other side is exposed to an environment at 93°C. The convection heat-transfer coefficient between the wall and the environment is 570 W/m2 °C. The thermal conductivity of the wall is 21 W/m °C. Calculate the maximum temperature in the wall. 

The two-dimensional solid shown in the accompanying figure generates heat internally at the rate of 90 MW/m2. Using the numerical method calculate the steady state nodal temperatures for k = 20 W/m °C. 

To illustrate the radiation formulation for numerical solution we consider the circular hole 2 cm in diameter and 3 cm deep, as shown in the accompanying figure. The hole is machined in a large block of metal, which is maintained at l000oC and has a surface emissivity of 0.6. The temperature of the large surrounding room is 20°C. A simple approach to this problem would assume the radiosity uniform over the entire heated internal surface. In reality, the radiosity varies over the suiface, and we break it into segments 1 (bottom of the hole), 2. 3, and 4 (sides of the hole) for analysis. 

The PTC phenomenon, in effect, provides the means of making a thermal switch, operated either by an external change in temperature or by an increase in current that generates heat internally, see Fig. 8.20. A common form of self-regulating heater is made by extruding a strip with the cross-section shown in Fig. 8.21, where the conductive component consists of polyethylene/carbon-black composite that is radiation-crosslinked after fabrication. The strip may be extruded in long lengths... 

W. E. Olmstead and M. E. Brodwin, A model for thermocouple sensitivity during microwave heating. International Journal of Heat and Mass Transfer, 40, 1559-1565 (1997). 

OC How arc heat, internal energy, and thermal energy related to each other ... 

In order to raise the temperature from 450° to about 850°C and to supply the endothermic heat of reduction — 40 kcal/mole), considerable heat must be supplied. Because of materials limitations at this high temperature, the most feasible way to supply the heat of reaction is to generate the heat internally by the combustion of carbon with air. This eliminates the need for heat transfer surfaces operating at high temperatures in a corrosive environment. 

---