Hot oil heating

Heat, hot oil, wear, and ozone resistance Hot oil, heat, and ozone resistance... 

K. Hot oil heat exchange system most special heat exchange fluids are flammable and are often used above their flash points so their use in a unit increases the risk of fire or explosion. The factor to apply depends on the quantity and whether the fluid is above or below its flash point see Table 5 in the Guide. 

K. Hot oil heat exchange system Not present, so the penalty is zero. 

Figure 3.14. The lower ends of fractionators, (a) Kettle reboiler. The heat source may be on TC of either of the two locations shown or on flow control, or on difference of pressure between key locations in the tower. Because of the built-in weir, no LC is needed. Less head room is needed than with the thermosiphon reboiler, (b) Thermosiphon reboiler. Compared with the kettle, the heat transfer coefficient is greater, the shorter residence time may prevent overheating of thermally sensitive materials, surface fouling will be less, and the smaller holdup of hot liquid is a safety precaution, (c) Forced circulation reboiler. High rate of heat transfer and a short residence time which is desirable with thermally sensitive materials are achieved, (d) Rate of supply of heat transfer medium is controlled by the difference in pressure between two key locations in the tower, (e) With the control valve in the condensate line, the rate of heat transfer is controlled by the amount of unflooded heat transfer surface present at any time, (f) Withdrawal on TC ensures that the product has the correct boiling point and presumably the correct composition. The LC on the steam supply ensures that the specified heat input is being maintained, (g) Cascade control The set point of the FC on the steam supply is adjusted by the TC to ensure constant temperature in the column, (h) Steam flow rate is controlled to ensure specified composition of the PF effluent. The composition may be measured directly or indirectly by measurement of some physical property such as vapor pressure, (i) The three-way valve in the hot oil heating supply prevents buildup of excessive pressure in case the flow to the reboiier is throttled substantially, (j) The three-way valve of case (i) is replaced by a two-way valve and a differential pressure controller. This method is more expensive but avoids use of the possibly troublesome three-way valve.

Oil baths are useful for heating mixtures. The contact of the flask with the hot oil heats the flask perfectly because the hot oil completely surrounds the sides of the flask. This results in even heating and effective temperature control. Oil baths are relatively inexpensive and are safe to operate because they lack an open flame. Oil baths are slow to heat, and they cool slowly after use. These are some of the drawbacks associated with oil baths. In addition, the flask retains an oily residue, which is slippery and must be cleaned off. 

Hot oil heat offers the benefits of higher temperatures from a liquid system. It results in probably the most uniform mold temperatures primarily because the fluid is being constantly circulated. Recovery time, however, is limited to the total heat capacity designed into the circulating unit. 

New pilot and commercial-scale equipment has been developed to blend and apply the composites and to determine total system costs (Figure 3). Several commercial-sized units based on the pilot design are now under construction. Each has a 500-gal capacity. They are fitted with a hot-oil heating system, heavy-duty mixers, and heated hoses that can deliver up to 200 lb/min of sulfur composite. They are designed to operate typically at 250°-300°F and at spray pressures of 20-100 psi. Each is self-contained except for electrical power which is provided by a stationary source or a portable generator. 

Economics Basis is a 200,000-tpy standard plant, West German conditions, December 2000, including compressor station, incinerator for wastewater and offgas, hot-oil heating system and catalyst... 

In LTTD, contaminated slurries are fed into the system, heated to 200° to 300°C by a hot oil heating chamber, and heated under elevated pressures. Emissions from the system are treated in an afterburner. 

The fire hazards of heptane are high. A low autoignition temperatiue makes the use of hot oil heating systems, which normally operate in the range 270-290 °C, undesirable. 

Hot oil heat exchange systems Since most hot oil (heat exchange) fluids will burn and are frequently used above their Hash points or boiling points, they represent an additional hazard in any process unit that uses them. A penalty factor between 0.25 and 1.15 is applied depending on quantity and temperature. 

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