Electrical heating system

M. J. Heim rich, S. Albu, and J. Osborne, Electrically Heated System Conversion on Two Current Technology Vehicles, SAE 910612, Society of Automotive Engineers, Warrendale, Pa., 1991. 

Steam, and other vapour heating systems, are intrinsically safe as the temperature cannot exceed the saturation temperature at the supply pressure. Other heating systems rely on control of the heating rate to limit the maximum process temperature. Electrical heating systems can be particularly hazardous. 

Lina, K. Zhang, Y. Xua, X. Dia, H. Yang, R. Qina, P., 2005, Experimental study of underfloor electric heating system with shape-stabilized PCM plates, Energy and Buildings 37 215-220. 

Five biomass samples (hazelnut shell, cotton cocoon shell, tea factory waste, olive husk and sprace wood) were pyrolyzed in a laboratory-scale apparatus designed for the purpose of pyrolysis (Demirbas, 2001, 2002a). Figure 6.4 shows the simple experimental setup of pyrolysis. The main element of the experimental device is a vertical cylindrical reactor of stainless steel, 127.0 nun in height, 17.0 nun iimer diameter and 25.0 mm outer diameter inserted vertically into an electrically heated tubular furnace and provided with an electrical heating system power source, with a heating rate of about 5 K/s. The biomass samples ground... 

Costs for catalytic oxidation systems are often included as a part of the entire remedial activity. Typical operating costs for a catalytic oxidation system alone, operating at 100 to 200 standard cubic feet per minute (scfm), will range from 8 to 15 per day (for natural gas or propane-fired systems) to 20 to 40 per day (for electrically heated systems). Capital costs of equipment operating at throughputs of 100 to 200 scfm are estimated to be in a range from 50,000 to 100,000 (D16641Q, p. 7). 

The furnaces are generally heated by the exhaust gases issued from the combustion of the pyrolitic gases. Cosa adopted an electrical heating system and Pyrovac a circulating molten salt system. 

The investigation of the autothermal operation of the hydrogasifier requires a detailed examination of the process heat balance. Concerning the thermobalance and PFB tests, neither the input heat of the electric heating system, nor the heat losses, are known. However, based on the experimental results, it seems that the methanation reaction is a major heat source in the hydrogasifier, followed by other hydrogenation reactions. 

Determination of volatiles at the trace level is also possible by pre-concentrating the headspace volatiles on a suitable adsorbent. The trapped compounds are subsequently recovered by thermal desorption in front of a cooled trap connected to the capillary column or by solvent elution followed by splitless or on-column injection. These methods, called dynamic headspace enrichment or purge-and-trap , have been applied to trace level analysis of volatiles, using conventional electrically heated systems [ 31, 32 ], a Curie-point Pyrolyser... 

Mayer D, Haubenwallner S, Kosmus W, et al. 1992 Modified electrical heating system for hydride generation atomic absorption spectrometry and elaboration of a digestion method for the determination of arsenic and selenium in biological materials. Anal Chim Acta 268(2) 315-321. 

Table 8.4. Advantages and disadvantages of electrical-heating systems.

A vigorous reaction (decomposition) may occur if the temperature rises above 150°. For this reason we advise against using an oil bath (with an electric heating system). This does not allow a satisfactory control of the temperature. We prefer heating with a free flame in this case (compare Exp. 25). 

Variable temperature cells are available which can be controlled to within 0.1°C over the range from -180 to 250°C. An electrical heating system is used for temperatures above ambient, with liquid nitrogen and a heater for low temperatures. These cells can be used to study phase transitions and the kinetics of reactions. As well as transmission temperature cells, variable temperature ATR cells and cells for microsampling are also available. 

Another application for electrical energy in chemical plants is in auxiliary electrical heating systems (e.g., to prevent freezing of pipelines during plant disturbances, especially in winter). 

Electric cartridge heaters are often used to heat elastomer molds and thermoset molds. Figure 4-9 shows a schematic diagram of an electric heating system. In this case, cartridge heaters are inserted into bores in the mold to achieve temperatures of 150-200°C (300-400°F) required for cross-linking. 

Figure 4-9 Schematic diagram of an electric heating system...

The pool-type Superphenix reactor (larger version of Phenix) consists of a main vessel filled with 3300 metric tonnes of sodium subjected to only 320 JEPP of radiation and currently maintained at 180°G by an external electric heating system on the security vessel, permissing shut down the primary pumps. 

Electrical heating systems can be broadly divided into two categories unrestricted local heating and off-peak heating. 

ELECTRICAL HEATING SYSTEMS FOR MELTING TANKS, FOREHEARTHS, AND FEEDERS... 

Electrical Heating Systems for Melting Tanks, Forehearths, and Feeders... 

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