Heat-Transfer Design

Fuel-fired furnaces primarily utilize carbonaceous or hydrocarbon fuels. Since the purpose of a furnace is to generate heat for some useful appHcation, flame temperature and heat transfer are important aspects of furnace design. Heat transfer is impacted by the flame emissivity. A high emissivity means strong radiation to the walls. 

The quahty of feed water required depends on boiler operating pressure, design, heat transfer rates, and steam use. Most boiler systems have sodium zeohte softened or demineralized makeup water. Feed-water hardness usually ranges from 0.01 to 2.0 ppm, but even water of this purity does not provide deposit-free operation. Therefore, good internal boiler water treatment programs are necessary. 

A boiler is a device for heating water or other liquids and is most commonly constructed as a closed pressure vessel, containing a furnace area, purpose-designed heat transfer surface areas, and other functional components. 

Four elements of microchannel scale-up models will be described pressure-drop design, heat-transfer design, reactor design, and mechanical and manufacturing designs. 

Make a preliminary mechanical design for the reactor the vessel design, heat-transfer surfaces, internals and general arrangement. 

The Fig. 22.1 economizer s design heat transfer rate with ... 

Description Styrene monomer, a small amount of solvent and additives are fed to the specially designed reactor (1) where the polymerization is carried out. The polymerization temperature of the reactor is carefully controlled at a constant level to keep the desired conversion rate. The heat of polymerization is easily removed by a specially designed heat-transfer system. 

Ing the economics of unit maintenance and proposed modifications. Deisobutanizer condenser performance is a good example. As these units age and their heat transfer capability decreases, there is a decline in the rate and/or purity of the Isobutane recycle stream. With a comprehensive simulation model, the evaluation of the economics of a turnaround can be made within a matter of days by using actual measured and design heat transfer coefficients. 

Source V. Ganapathy, Simplified Approach to Designing Heat Transfer Equipment, Courtesy o/Chem. Eng., April 13, 1987, pp. 88-87. 

Selections A 100-gal still pot containing 71 ft of IJ -in. BWG 16 stainless-steel tubing will be tised. The designed heat-transfer area is 37.2 ft. ... 

In terms of engineering design, heat transfer is of paramount importance as... 

Fouling coefficients recommended for use in designing heat-transfer equipment are available in many references (P3, Nl). A short tabulation of some typical fouling coefficients is given in Table 4.9-1. 

At this stage, the reader should compare the unit operations of the ammonia and sulphuric acid processes. Although some processes have special requirements, it should already be clear that the chemical engineer can apply his experience of designing heat transfer equipment for ammonia production to similar sorts of problems in nylon, drug or refrigerant production. The links with the food industry is the next subject. 

Design heat transfer snrface - the total surface of all the heat exchanging tubes in one steam generator. It is the product of the total number of tubes in a new SG and the lateral area of a tube (cylinder). The actual value may decrease during plant service as a result of successive plugging of leaking tubes. The original (as manufactured) value should be entered in m. ... 

Heat transfer surface per steam generator [m2] Modified to Design heat transfer surface ... 

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