Heat source, burner

Because indirect-heat calciners frequently require close-fitting gas seals, it is customaiy to support aU parts on a selFcontained frame, for sizes up to approximately 2 m in diameter. The furnace can employ elec tric heating elements or oil and/or gas burners as the heat source for the process. The hardware would be zoned down the length of the furnace to match the heat requirements of the process. Process control is normaUy by shell temperature, measured by thermocouples or radiation pyrometers. When a special gas atmosphere must be maintained inside the cyhnder, positive rotaiy gas se s, with one or more pressurized and purged annular chambers, are employed. The diaphragm-type seal ABB Raymond (Bartlett-Snow TM) is suitable for pressures up to 5 cm of water, with no detectable leakage. 

For this and subsequent demonstrations involving a heat source, use a gas torch such as the Sievert self-blowing propane outfit (W. A. Meyer Ltd., 9/11 Gleneldon Road, London SW16 2AU, or from most tool shops) this comprises 3.9-kg propane bottle, 3085 hose-failure valve, fitted pressure hose no. 16310,3486 torch, 2941 burner. 

While fire is now rarely used in synthetic chemistry, it was not until Robert Bunsen invented the burner in 1855 that the energy from this heat source could be applied... 

In the trough test, the sample (only solids) is introduced in a horizontal wire mesh cage with an inner volume of 11 liters. The substance is initiated at one end of this trough by a gas burner or electrical heating source and the propagation of the deflagration front is established and noted. 

The heat transfer through the same composition mastic by flame temperature of 2000 F. directed against it is illustrated by three test panels of steel 3/16 inch thick and 12 inches square. One panel was soated with 9/16 inch of mastic, and the second bad steel wire lath welded on a five points and then covered with 1/2 inch of mastic the third panel was left bare. The source of fire for the tests was a large gas burner with forced air feed. Temperatures of the heat source and heat transfer on the uninsulated side were made with the thermocouple. The results of the fire test were as... 

In the case of solar powered systems, decoupling of heat source and chemical plant facilitates the compensation of fluctuating and intermittent available power input. This is particularly important if units of the chemical system require steady-state conditions over long periods. Beyond that decoupled systems allow for an easier integration of thermal and chemical storage units to compensate daily or seasonal variation of solar supply. The same applies for hybrid operation, i.e. the combination with burner firing or with a nuclear heat source. 

Fortunately, the use of oil lamps is now neither common nor necessary. Although there are modem substitutes for oil lamps, such as Bunsen and Fisher burners, they are not the heating mechanism of choice because most heating is done by electric mantels and stirrer/hot plates. There are too many drawbacks associated with open-flame heat sources for them to be considered the heat source of choice. The problems associated with these burners include the following ... 

Figure 026. Fractional distillation apparatus for the fractional distillation of chloroform. The heating mantle can be replaced with a Bunsen burner, but the flame should not touch the glass. A hot place or stovetop can also be used as a heat source if...

The conventional gas burner was connected in series with the heat exchanger (Fig. 2). The gas burner then could assist with initial startup and could supplement the heat exchanger if it became necessary. Both the modulating valve and the gas burner were regulated by the same temperature controller. The incinerator heat exchanger was the primary heat source, and the gas burner was the secondary source. The control system automatically turns off the gas burner when the incinerator heat is sufficient to satisfy the demand. 

Note If you are using a hot plate as your heat source, use the 400 mL beaker. If you are using a laboratory burner, use the porcelain evaporating dish. 

Heat can be supplied into the reactor bed to maintain the reaction with a very small temperature drop by using the heat pipes. Each heat pipe has its evaporator section connected to the heat source and its condenser section connected to the reactor bed. The heat source may comprise a furnace containing a burner. To further improve heat transfer, the heat pipes can have heat transfer fins on their outer surfaces within the reactor. 

The advantages of the burner are that the heat source can be removed instantly from the apparatus and that the flame is visible in contrast you often cannot distinguish between a cold and hot metal surface. The disadvantages are those of an open flame. 

These can be used instead of Bunsen burners or microbumers provided that the temperature required is not too high. The main uses of hot-air guns are for drying glassware and as a heat source for distillation of liquids at relatively moderate temperatures up to about 120 °C. 

Be careful with hot plates, Bunsen burners, and other heat sources. 

Use proper procedures when lighting Bunsen burners. Turn off hot plates, Bunsen burners, and other heat sources when they are not in use. (Rule applies)... 

Use flammable liquids only in small amounts. When working with flammable liquids, be sure that no one else in the lab is using a lit Bunsen burner or plans to use one. Make sure there are no other heat sources present. 

An open-cycle layout is by far the most common in industrial spray drying. The open layout involves intake of drying air from the atmosphere and discharge of exhaust air to the atmosphere. Drying air can be supplemented by a waste heat source to reduce overall fuel consumption. The heater may be direct, i.e., natural gas burner, or indirect by steam-heated heat exchanger. 

L beaker, hcatcr-stirrcr hotplate with stir bar (oder gas burner as heat source and stirring rod), thermometer, 1-mL pipette, safety glasses, protective gloves. 

OK, get a ringstand and an extension clamp and a clamp fastener and put them all together. What heat source A Bunsen burner, and you ll need more room than you do with a heating mantle (see Chapter 18, Sources of Heat ). In any case, you don t know where the receiving flask will show up, and then you might have to readjust the entire setup. Yes, you should have read the experiment before so you d know about the heating mantles. 

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