Infrared furnace

Because powdered activated carbon is generally used in relatively small quantities, the spent carbon has often been disposed of in landfills. However, landfill disposal is becoming more restrictive environmentally and more costiy. Thus large consumers of powdered carbon find that regeneration is an attractive alternative. Examples of regeneration systems for powdered activated carbon include the Zimpro/Passavant wet air oxidation process (46), the multihearth furnace as used in the DuPont PACT process (47,48), and the Shirco infrared furnace (49,50). 

Generally, high-temperature systems operate at temperatures above 1000°F (500-600°C), whereas low-temperature systems operate below 1000°F. High-temperature processes include (1) incineration, (2) electric pyrolysis, and (3) in situ vitrification. Low-temperature treatment systems include (1) soil roasting, (2) low-temperature incineration, (3) low-temperature thermal aeration, (4) infrared furnace treatment, and (5) low-temperature thermal stripping. 

Figure 1 is a schematic of one of the two supercritical flow reactors used in this work. The system is first brought up to the operating pressure by an air compressor. An HPLC pump forces the reactant solution through the reactor, the ten-port valve and dual-loop sampling system, and into the product accumulator, where the flow of products displaces air through a back-pressure regulator. The reactant inflow is rapidly heated to reaction temperature by an electric entry heater/water jacket combination, and maintained at isothermal conditions by a Transtemp Infrared furnace and an exit electric heater/water jacket combination. 

Granular Activated Carbon Adsorption with On-Site Infrared Furnace Reactivation... 

Conventional air ovens or infrared furnaces with appropriate conveyers can be used for the post baking. Figure 63.29 shows a 100 micrometer hole made by photoimageable process. 

Thick-film metallizations for solar cells are processed in infrared-heated furnaces. These furnaces utilize infrared lamps as the source of heat. With infrared furnaces, it is possible to maintain very short dwell times at peak firing temperatures. 

Laser Raman diagnostic teclmiques offer remote, nonintnisive, nonperturbing measurements with high spatial and temporal resolution [158], This is particularly advantageous in the area of combustion chemistry. Physical probes for temperature and concentration measurements can be debatable in many combustion systems, such as furnaces, internal combustors etc., since they may disturb the medium or, even worse, not withstand the hostile enviromnents [159]. Laser Raman techniques are employed since two of the dominant molecules associated with air-fed combustion are O2 and N2. Flomonuclear diatomic molecules unable to have a nuclear coordinate-dependent dipole moment caimot be diagnosed by infrared spectroscopy. Other combustion species include CFl, CO2, FI2O and FI2 [160]. These molecules are probed by Raman spectroscopy to detenuine the temperature profile and species concentration m various combustion processes. 

Gaseous Combustion Products Radiation from water vapor and carbon dioxide occurs in spectral bands in the infrared. In magnitude it overshadows convection at furnace temperatures. 

Infrared radiation or closed cycle convection curing furnace... 

Infrared thermometry is to identify the maximum permissible temperature of tube alloys, to determine furnace heat flux, scale heat conductivity, and tube heat transfer rates. 

FIR Far infrared GFAES Graphite furnace atomic emission... 

The Subpart O standards apply to units that treat or destroy hazardous waste and which meet the definition of an incinerator. An incinerator is any enclosed device that uses controlled flame combustion and does not meet the criteria for classification as a boiler, sludge dryer, carbon regeneration unit, or industrial furnace. Typical incinerators1 2 3 include rotary kilns, liquid injectors, fixed hearth units, and fluidized bed incinerators (Table 23.1). The definition of an incinerator also includes units that meet the definition of an infrared incinerator or plasma arc incinerator. An infrared incinerator is any enclosed device that uses electric-powered resistance as a source of heat and which is not listed as an industrial furnace. A plasma arc incinerator is any enclosed device that uses a high-intensity electrical discharge as a source of heat and which is not listed as an industrial furnace. 

Van Hall et al. [100] inject a 20 litre sample into a high-temperature furnace at 950 °C containing catalyst to promote oxidation of carbon compounds to carbon dioxide, which is then passed into a non-dispersive infrared analyser. The carbonate interference can be determined by passing an acidified portion of the sample through a low-temperature furnace [101-103]. 

But not all materials emit the same amount of light when heated to the same temperature there is a spectral distribution of electromagnetic waves. For example, a piece of glass and a piece of iron when heated in the same furnace look different the glass is nearly colourless yet feels hotter to the skin because it emits more infrared light conversely, the iron glows because it emits visible as well as infrared light. 

Krambeck et al. [40] measured small quantities of particulate carbon in lake waters by an automated furnace combustion infrared procedure. The whole sequence of operations was controlled with the aid of an AIM65 desktop computer. The system was successfully operated for routine analysis of samples of lake water with particulate organic carbon values of 100-300ug L 1 carbon a single analysis takes 8min. The relative standard deviation was about 1%. 

The bomb method for sulfur determination (ASTM D129) uses sample combustion in oxygen and conversion of the sulfur to barium sulfate, which is determined by mass. This method is suitable for samples containing 0.1 to 5.0% w/w sulfur and can be used for most low-volatility petroleum products. Elements that produce residues insoluble in hydrochloric acid interfere with this method this includes aluminum, calcium, iron, lead, and silicon, plus minerals such as asbestos, mica, and silica, and an alternative method (ASTM D1552) is preferred. This method describes three procedures the sample is first pyrolyzed in either an induction furnace or a resistance furnace the sulfur is then converted to sulfur dioxide, and the sulfur dioxide is either titrated with potassium iodate-starch reagent or is analyzed by infrared spectroscopy. This method is generally suitable for samples containing from 0.06 to 8.0% w/w sulfur that distill at temperatures above 177°C (351°F). 

In the infrared detection system, the sample is weighed into a special ceramic boat which is then placed into a combustion furnace at 1371°C (2500°F) in an oxygen atmosphere. Most of the sulfur present is converted to sulfur dioxide, which is then measured with an infrared detector after moisture and dust are removed by traps. The calibration factor is determined using standards approximating the material to be analyzed. 

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