Fired heaters fitting

Suppose a fired heater in an oil refinery, in service to heat crude oil, is fitted with a new air preheater. The firebox was running hot before the air preheater was installed, but the management was convinced that the installation of the air preheater would allow them to heat more crude oil. When the heater with its new air preheater came back on line, the following changes were noted ... 

TUBES, TUBE FITTINGS AND HEADERS FOR FIRED HEATERS-... 

The U.S. Radiant Smoke Toxicity Apparatus [133] consists of the lest cabinet of the NBS Protocol [128], but the test specimen, 76 x 125 x 51 mm thick, is decomposed by a radiant heater fitted beneath the smoke box see Fig. 23. The maximum heat flux is 50 kW, mv This equipment was developed following criticism of the fire model of the NBS Protocol. 

There are two basic types of IR heaters electric IR and gas-fired IR (Figure 46.16). The most important element of the IR drying system is the IR emitter. These two types of IR heaters fit into three temperature ranges (1) 343°C-538°C (e.g gas and electric IR) (2) 538°C-1100°C (e.g gas and electric IR) and (3) 1100°C-2200°C (e.g., electric IR only). Electrically heated or natural-gas-heated units are used mainly to preheat the web, although these can be used in principle to carry out the entire drying process. IR temperatures are typically in the 650°C-1200°C range. Improved drying rates can be obtained by a combined radiation-convection system. 

Fresh waters are, in general, less corrosive towards copper than is sea-water, and copper is widely and satisfactorily used for distributing cold and hot waters in domestic and industrial installations . Copper and copper alloys are used for pipes, hot-water cylinders, fire-back boilers, ball floats, ball valves, taps, fittings, heater sheaths, etc. In condensers and heat exchangers using fresh water for cooling, tubes of 70/30 brass or Admiralty brass are usually used, and corrosion is rarely a problem. 

Both types of boiler systems may incorporate finned copper heating coils, which are located above the furnace and gas-pass tubes (smoke tubes or fire tubes) and provide for indirect heating of domestic HW. Where coils are fitted and the boilers are only fired during winter months, domestic HW heating usually is provided via gas heaters for the summer. 

The heater for the reaction chamber and the conductors were printed on the lowest layer and electrically contacted to the pads on the cover layer by vertical metal-filled vias in every intermediate layer. Still some manual work was necessary to shape the reaction channel from the pre-fired tapes. Also the soldering of clamp-type fittings to the cover layer is certainly difficult to automate. However, a manufacturing process for ceramic foil reactors seems to be within reach. 

Rotary kilns fitted with pre-heaters (type K in Table 16.1 Figs. 16.16 and 16.17) are generally considerably shorter than the conventional rotary kiln (e.g. 40 to 60 m). The heat usage decreases because of reduced radiation and convection losses as well as the increased heat recovery from the exhaust gases. Thus, with coal firing, net heat usages below 1250 kcal/kg are reported. 

Facilities for rest and eating meals must be provided so that workers may sit down during break times in areas where they do not need to wear personal protective equipment. It should be possible for workers to make hot drinks and prepare food. Separate rooms should be provided for smokers and non-smokers. Facilities should also be provided for pregnant women and nursing mothers to rest. Arrangements must be in place to ensure that food is not contaminated by hazardous substances. Many fires have been caused by placing clothes on an electric heater. Damp clothes should not be positioned in contact with the heater and there should be adequate ventilation around the heater. If possible, the heater should be fitted with a high temperature cut-out device. 

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