Coal characteristic curve

You must chose a centrifugal pump to pump a coal slurry. You have determined that the pump must deliver 200 gpm at a pressure of at least 35 psi. Given the pump characteristic curves in Appendix H, tell which pump you would specify (give pump size, speed, and impeller diameter) and why What is the efficiency of this pump at its operating point, what horsepower motor would be required to drive the pump, and what is the required NPSH of the pump The specific gravity of the slurry is 1.35. 

Figure 13.20 DTA-EG-GC pyrolysis characteristic curves of bituminous coal [14-17]...

Figure 13.22 DTA-EGD-GC pyrolysis characteristic curves of lignite coal...

Various mechanisms and kinetics of coal liquefaction have been proposed and examined by many investiga tors(l,2,4-8). As a general kinetic model of coal lique-action, scheme 1 was assumed. The reaction rate of every reaction step in the scheme assumed to be first order with respect to reacting species and dissolved hydrogen. A few typical cases of a general kinetic model and the general characteristics for their cases are illustrated on Table 3. When compared these typical figures, the curves are apparently different in shape. 

Authors concluded, that although the swelling degree is not directly connected with molecular characteristics of absorbed liquids, however determining factor is their parameter of solubility in spite of the fact that at detailed consideration of the dependencies Q =f(3) (or f(32)) there are a number of deviations (as same as in the work [5]) from the ideal curve for many solvents. It is necessary to notify that although it is hard to estimate the verisimilitude of determined in such a way molecular weights of structural links of a coal between the points of cross bonds, however, in a case of synthetic polymers in a same way determined masses of links visible don t agree with the values obtained in accordance with others methods. 

Figure 17-46 shows such a performance curve for the collection of coal fly ash by a pilot-plant venturi scrubber (Raben "Use of Scrubbers for Control of Emissions from Power Boilers, United States-U.S.S.R. Symposium on Control of Fine-Particulate Emissions from Industrial Sources, San Francisco, 1974). The scatter in the data reflects not merely experimental errors but actual variations in the particle-size characteristics of the dust. Because the characteristics of an industrial dust vary with time, the scrubber performance curve necessarily must represent an average material, and the scatter in the data is frequently greater than is shown in Fig. 17-46. For best definition, the curve should cover as wide a range of contacting power as possible. Obtaining the data thus requires pilot-plant equipment with the flexibility to operate over a wide range of conditions. Because scrubber performance is not greatly affected by the size of the unit, it is feasible to conduct the tests with a unit handling no more than 170 m3/h (100 ftVmin) of gas.

The dose distribution in the materials is given as a depth-dose curve. An example of the curve is illustrated in Fig. 4 obtained with the irradiation of electron from 0.5 to 1.0 MeV using cellulose triacetate (CTA) film dosimeter [12]. The existence of the maximum dose is an important characteristic of the depth-dose curve. Irradiation from two opposite sides by using two accelerators was proposed in order to give better uniformity in water [13]. The uniform irradiation is also important for flue gas treatment. Better efficiency of NO removal was proved with both-side irradiation by using three accelerators for coal-fired flue gas than single-side irradiation at the same dose [14]. 

The distinguishing characteristic of the scattering curves for the anthracites is the outer part of the scattering curve, where the intensity is usually higher than for the lower-rank coals, and, though sometimes nearly constant, usually decreases smoothly. 

At temperatures above the softening point, isotropic pitch often displays Newtonian flow characteristics (18,19), but this may well depend upon the concentration of any insoluble particles (i.e., primary QI in the case of coal tar based materials) present within the pitch. A high concentration of QI could lead to non-Newtonian character as a result of the particle-particle attractive forces. Figure 3 shows n -T curves for a variety of pitch materials and their pyrolysis products. Pyrolysis increases the Tg of the system and shifts the viscosity-temperature curve to higher temperatures. 

Coals were devolatilized at rates comparable with those encountered in combustion and gasification processes. Rapid pyrolysis was attained with pulse-heating equipment developed for this purpose. This technique permitted control of the heating time and the final temperature of the coal samples. Subbituminous A to low volatile bituminous coals were studied. All bituminous coals exhibited devolatilization curves which were characteristically similar, but devolatilization curves of subbituminous A coal differed markedly. The products of devolatilization were gases, condensable material or tar, and residual char. Mass spectrometric analysis showed the gas to consist principally of H2, CHh, and CO. Higher hydrocarbons, up to C6, were present in small quantities. 

Figure 2 shows typical, smoothed, weight loss-o. -time characteristics obtained using an air-pretreated hvab Pittsburgh coal char from the Ireland mine. These curves are discussed in more detail later. The composition of the coal char, used extensively in the experimental study, is given in Table I. 

Measured the relationship between the gas desorption index of drill cuttings K, and gas pressure of the coal samples in the laboratory, and draw the relation-curves of K, and gas content W combined with the proximate analysis of the samples. The relation between K, and W is in accords with exponential function by performing analysis of the measured data. According to the physical chemistry theory, the non-linear characteristic between the two is caused by the diffusion coefficient changing constantly with the gas content in... 

During the last two decades, the DTA-EGD-GC on-line coupled simultaneous apparatus has been applied in the following fields solid catalysts [77-79], anti-oxidation additives in petroleum [80], thermal characteristics of coal [81-83], mineralogy [60, 84-87], organometallic chemistry [88-90], polymer chemistry [91], pharmaceutical chemistry [92], environmental protection chemistry and the thermal behavior of all kinds of chemical compounds [62, 63]. Numerous DTA-EGD-GC curves are shown in Chapter 13. 

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