Temperature rise ratio

Normalized adiabatic temperature rise (ratio of available reaction heat to feed heat capacity normalized by the activation energy) ... 

Various approaches have been developed to overcome this problem. The simplest is to add 1 to 2 % of water while grinding the quicklime. This results in a small amount of calcium hydroxide being formed on the surface of the quicklime particles. The main consequence of this water addition is an improvement in dispersion. It also reduces the temperature rise ratio and the final temperature rise (see Fig. 26.7), both of which are favourable effects. 

T2 temperature rise at 2 minutes (°C) T maximum temperature rise (°C) tf time at which temperature falls (by 0.2 °C) temperature rise ratio = T2 -r- Tm... 

Calculate the temperature rise ratio (temperature rise at 2 min. divided by the maximum temperature rise), which is a convenient indication of the shape of the curve. 

Where a high degree of consistency is required, it is recommended that all of the above parameters are monitored, namely 2-minute temperature, maximum temperature, time to maximum temperature, turn-down time and temperature rise ratio. 

As the temperature of the liquid phase is increased, the system ultimately reaches a phase boundary, the bubble point at which the gas phase (vapour) begins to appear, with the composition shown at the left end of the horizontal two-phase tie-line . As the temperature rises more gas appears and the relative amounts of the two phases are detemiined by applying a lever-ami principle to the tie-line the ratio of the fractionof molecules in the gas phase to that hn the liquid phase is given by the inverse of the ratio of the distances from the phase boundary to the position of the overall mole fraction Xq of the system. 

These effects of differential vapor pressures on isotope ratios are important for gases and liquids at near-ambient temperatures. As temperature rises, the differences for volatile materials become less and less. However, diffusion processes are also important, and these increase in importance as temperature rises, particularly in rocks and similar natural materials. Minerals can exchange oxygen with the atmosphere, or rocks can affect each other by diffusion of ions from one type into another and vice versa. Such changes can be used to interpret the temperatures to which rocks have been subjected during or after their formation. 

The measuring of temperature rise permits monitoring efficiency for a fixed pressure ratio and suction temperature. Efficiencies should always exceed 0.6, and 1.00 is approachable in reciprocating devices. Their better efficiency needs to be balanced against their greater cost, greater maintenance, and lower capacity. 

Metallic Diaphragm Compressors (Fig. 10-99) These are available for small quantities [up to about 17 mvh (10 ftVmin)] for compression ratios as high as 10 I per stage. Temperature rise is not a... 

When the exit-liquor temperature rises owing to the heat of absorption of the solute, the value of m changes through the tower, and the liquid-to-gas ratio must be chosen to give reasonable values of miG ilh. and where the subscripts 1 and 2 refer to the bot-... 

For copper windings, the temperature rise /2-/a may be obtained from the ratio of the resistance by... 

Ta = inlet temperature Pa = pressure at eompressor outlet Pa = pressure at eompressor inlet A Tad = aetual temperature rise in the eompressor 7 = speeifie heat ratio average value between inlet and outlet temperature was used... 

Cp a = specific heat of air at constant pressure AT jj = temperature rise for stoichiometric combustion D = surface average particle diameter Pa = air density Pf = fuel density

equivalence ratio B = mass transfer number... 

In the ease of exothermie or endothermie reaetions, seale-up may impair eonditions for heat input or removal beeause the ratio of the heat transfer surfaee area to the reaetor volume is redueed. Identieal eonditions for heat transfer in both the model and full-seale plants may be aehieved in exothermal reaetions if both have the same thermal stability eoeffieient. This requirement is obtained by introdueing external heat exehangers. Alternatively, a reaetor with a strong exothermie reaetion ean be divided into several small size reaetors. In this manner, the ratio of the external heat transfer surfaee area to the reaetor volume is inereased, thereby avoiding an exeessive temperature rise in the reaetor. 

Heat exchanger Effectiveness (or thermal ratio) e = Temperature rise (cold side (/maximum temperature difference between entry (hot side) and entry (cold side)... 

The temperature rise in the combustion chamber may then be determined from Eq. (3.33), in the approximate form (Tj T2) = (af + b). Strictly a and b are functions of the temperature of the reactants and the fuel-air ratio/, but fixed values are assumed to cover a reasonable range of conditions. Accordingly, the fuel-air ratio may be expressed as... 

A reversible cycle with turbine expansion split into two steps (high pressure, HP, and low pressure, LP) is illustrated in the T, s diagram of Fig. 4.3. The mass flow through the heater is still unity and the temperature rises from T2 to Tt, = Tq hence the heat supplied (3b is unchanged, as is the overall isentropic temperature ratio (x). But cooling air of mass flow i//H is used at entry to the first HP turbine (of isentropic temperature ratio. xh) and additional cooling of mass flow is introduced subsequently into the LP turbine (of isentropic temperature ratio Xl)- The total cooling flow is then i/( = i/ h + >h.-... 

Non-lubricated screw compressors have very close clearances and thus they are designed for limited ranges of discharge temperature, temperature rise, compression ratio, etc., all of which can cause changes in thesc clearances. Lubricated compressors have a somewhat broader tolerance to changes in operating conditions, but they are still more limited than reciprocating compressors. 

In the second case, temperature rises very rapidly, so the liquid is not heated to a temperature above the superheat limit temperature at failure, and no liquid flashing occurs. To demonstrate the influence of fill ratio, cases of 80% and 10% fill ratio are considered. 

Polytropic Efficiency. This is the ratio of theoretical polytropic horsepower to actual brake horsepower at the compressor shaft. The polytropic efficiency does not include packing, bearing, or other losses. This efficiency is a measure of the hydraulic perfection of the compressor, and the value remains the same for any gas and for any speed (within reasonable limits). For an uncooled compressor, the polytropic, hydraulic, and temperature rise efficiencies are the same. ... 

Major process conditions for experiment HGR-13 are plotted vs. stream time in Figure 6. The total recycle ratio was held relatively constant at 10 1 which resulted in a constant temperature rise of about 100°C across the catalyst bed (300°C at the inlet, 400°C maximum). Near the end of the experiment, the cold recycle ratio was varied from 8 1 to 1 1. The experiment was ended at 1368 hrs. 

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