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Calculating Load Heating Curves

The objective of this exercise is to develop a set of time/temperature curves such as shown in figs. 6.26 to 6.33 and figure 8.1. In this book, the authors frequently urge the readers to use this Shannon Method to develop such curves for their own specific loads, processes, and heating equipment so that they can better analyze their furnace capabilities and requirements, and make good engineering judgments relative to their control. [Pg.341]

On figure 8.1, the 20 abscissa units = 100% of time or distance in the furnace. For sample problem 8.1.1, with 890 ft (24.4 m) inside furnace length, each division therefore represents 880/20 = 4 ft or 1.22 m. Other given data are 2068 /pc 0.6687pc center to center 200 000 /hr. [Pg.341]

The total time for each load piece in the furnace = [Pg.341]

If engineering departments calculated heating curves specifically for their furnaces and loads, they would be able to determine correct specifications for the furnace to meet their specific needs. In addition, when required to reduce costs, they could be aware of the results and inform plant management of the limitations imposed on the [Pg.341]

Industrial Furnaces, Sixth Edition W. Trinks, M. H. Mawhinney, R. A. Shannon, R. J. Reed and J. R. Garvey Copyright 2004 John Wiley Sons, Inc. [Pg.341]


CALCULATING LOAD HEATING CURVES 347 TABLE 8.3 Comparison of two-side heating and four-side heating ... [Pg.347]

CALCULATING LOAD HEATING CURVES 361 TABLE 8.7 Heat transfer calculation worksheet (continues on table 8.8)... [Pg.361]

The percent loading may also be calculated from these curves (Table 1). It is observed that loading is relatively time independent. Reaction temperature and the ration of j. MCM-41 control the loading percent if a minimum heating time of 12 hours is allowed to elapse. In the... [Pg.306]

Usually, a prerequisite for determining a weighted MTD is a heat release curve. It is used for a guide in determining where to zone the heat transfer calculations. A heat release curve is a plot of heat load vs. temperature of both shell and tube fluids. An example of this can be seen in Figure 2-21. [Pg.42]

Current practice requires engineers to have more than a feel for load heating patterns (time-temperature profiles). They must acquire an ability to determine the effects of many operating and design variables on various loads time-temperature curves. The Shannon Method, which enables one to calculate specific time-temperature curves, is discussed briefly several places in this book and then detailed in chapter 8. The reader is encouraged to adapt the Shannon Method for processes other than the steel reheat and forging cases illustrated here. [Pg.79]

Fig. 6.6. Calculated time-temperature heating curves for a rotary hearth donut furnace showing the effects of delays before addition of enhanced heating burners. (Directions for calculating time-temperature curves are given in chap. 8.) The top two curves show what happens upon restart at normal tph after a delay. The bottom curve shows that loads charged after resumption will be too cold to roll, forcing a fall back to half the normal tph. Fig. 6.6. Calculated time-temperature heating curves for a rotary hearth donut furnace showing the effects of delays before addition of enhanced heating burners. (Directions for calculating time-temperature curves are given in chap. 8.) The top two curves show what happens upon restart at normal tph after a delay. The bottom curve shows that loads charged after resumption will be too cold to roll, forcing a fall back to half the normal tph.
To determine htflue port size, the firing rate should be calculated from a heating curve (chap. 8). Flowever, the required firing rate can be calculated if the following information is known a) weight of loads to be heated per hour, b) final load temperature required, (c) rate of temperature rise, (heat losses expected, e) a conservative flue gas temperature expected, and (f) a conservative air/fuel ratio. [Pg.316]

Three load temperature curves, for the load surface, load average, and load core (or load bottom in the case of one-side heating) will be assembled in section 8.1.3. Identify the job with a title box containing information such as owner, furnace identity, load description, design production rate, graph number, furnace type, process, load spacing, expected fuel rate, emissivity, person making the calculation, and date. [Pg.349]

An analytical expression given by El-Wakil (1978), which correlates with the decay heat curves of ANL report (ANL, 1963), estimates heat loads about one-half the heat loads calculated above. This heat load expression is... [Pg.728]

Calculate the gas cooling and condensing heat loads for each increment separately and plot a curve representing the total heat load versus temperature. [Pg.146]

The isosteric heats of adsorption, AH so, were calculated as a function of nitrogen loading for each of the samples tested. For each sample, the AHiS0 was found to decrease logarithmically with increased loading and this functionality is consistent with the assumptions of the Freundlich adsorption equation. As before, the brevity of presentation, the heat of adsorption data were curve fitted to an equation of the form ... [Pg.337]

Multiple layers of low conductivity phenolic foam insulation and small temperature differences between the primary coolant and the ambient minimized the heat loss from the primary loop to the ambient. Also, the heat addition to this loop was minimized by using a recirculation pump with an extremely low heat dissipation rate, which was calculated from the pump curves supplied by the manufacturer. With the pump heat dissipation and the ambient heat loss being small fractions of the secondary loop duty, the test section heat load was relatively insensitive to these losses and gains. Local heat transfer coefficients were therefore measured accurately in small increments for the entire saturated vapor-liquid region. Additional details of this thermal amplification technique are provided in the paper by Garimella and Bandhauer [32]. [Pg.286]

Since ABS copolymer has a large deformability associated with a poor thermal conductivity, the total work done on a specimen during the loading process may convert to deformation heat, which affects ABS flow behaviour, particularly at a high strain-rate loading. Thus, the effect of temperature rise during deformation must be taken into craisideration. From the tme stress-strain curves of Fig. 1, the temperature rise in a specimen can be calculated as a function of strain for each strain-rate level by an integral form of... [Pg.234]

The lower solid-line curve in Fig. A3.J represents the total heat production in the reflector calculated from theoretical considerations. This calculation was based oh the neutron distribution for a thinner slab pile (70 by 11 by 60 cm) where the heat load in the reflector is somewhat heavier than in the case of the assembly in which our measurements were made (71 by 17 by 66 cm). The measured spatial thermal-neutron distribution in this assembly is shown as a dotted curve. [Pg.459]


See other pages where Calculating Load Heating Curves is mentioned: [Pg.341]    [Pg.343]    [Pg.345]    [Pg.349]    [Pg.351]    [Pg.353]    [Pg.357]    [Pg.359]    [Pg.363]    [Pg.365]    [Pg.367]    [Pg.369]    [Pg.371]    [Pg.373]    [Pg.375]    [Pg.377]    [Pg.341]    [Pg.343]    [Pg.345]    [Pg.349]    [Pg.351]    [Pg.353]    [Pg.357]    [Pg.359]    [Pg.363]    [Pg.365]    [Pg.367]    [Pg.369]    [Pg.371]    [Pg.373]    [Pg.375]    [Pg.377]    [Pg.438]    [Pg.207]    [Pg.254]    [Pg.110]    [Pg.187]    [Pg.249]    [Pg.373]    [Pg.525]    [Pg.126]    [Pg.15]    [Pg.276]    [Pg.199]    [Pg.390]    [Pg.488]    [Pg.202]    [Pg.323]    [Pg.533]    [Pg.354]    [Pg.355]   


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