Total heating value

Pressure, temperature, and enthalpy or total heat values may be obtained from tables or diagrams covering each particular refrigerant. Table 11-12 presents a few comparative values of boiling points (evaporator temperature) and corresponding pressures as taken from such data. 

In cases where the aromatic C—C bonds were attacked and various water-soluble substances capable of extraction from oil were formed, a reduction in the total heating value of the fuel was consequently observed [137], Hence, such reaction was categorized as an industrially unacceptable reaction, since that pathway not only destroyed the carbon skeleton reducing the energy content of fuel but also converted DBT to 3-hydroxy-2-formylbenzothiophene without actually desulfurizing it to HBP. 

Cold gas conversion efficiency is the ratio of the gasifier fuel gas total heating value [i.e., (heating value)(mass flow)] to that of the coal feed, [(heating value)(mass flow)]. 

As new criteria are developed for defining combustibility, a method is needed to realistically indicate heat release rate of wood products exposed to building fires instead of dependence on "total heat values."... 

The lack of interest in the chemical aspects of this subject has in part been justified by some indications that there is little difference in the total heat value of the natural fuels. However, there is a growing realization that the differences in chemical composition and variation in the chemical reactions involved could materially affect or alter the rate of burning and the spreading of fire. 

It may be assumed that 7.5 lb of dry gas is generated for every 10,000 Btu of waste burned in the incinerator. In addition, 0.51 lb of moisture is produced for every 10,000 Btu of waste fired. Air cools the incinerator shell at a flow of 10,000 Ib/h (this air is discharged to the atmosphere at 400°F). Assume the air entering the incinerator has a humidity of 0.015 lb of moisture per pound of dry air and the ash produced has a heating value of lOOBtu/lb (assume no fly ash). The radiation heat loss from the shell is 1% of the total heating value of the waste. The temperature of the products of combustion (the flue gas) must not be less than 2000°F. The following information is required ... 

Determine the total heating value of the waste charged to the incinerator in Btu/h ... 

A relative measure of the thermal efficiency of the process is shown in Figure X. This shows the total heating value of the gas as a percentage of the total heating value of the feed. The relative values depend primarily on gas heating value and total gas yield. 

Equation (F.l) shows that each stream makes a contribution to total heat transfer area defined only by its duty, position in the composite curves, and its h value. This contribution to area means also a contribution to capital cost. If, for example, a corrosive stream requires special materials of construction, it will have a greater contribution to capital cost than a similar noncorrosive stream. If only one cost law is to be used for a network comprising mixed materials of construction, the area contribution of streams requiring special materials must somehow increase. One way this may be done is by weighting the heat transfer coefficients to reflect the cost of the material the stream requires. 

Od condensed from the released volatdes from the second stage is filtered and catalyticady hydrotreated at high pressure to produce a synthetic cmde od. Medium heat-content gas produced after the removal of H2S and CO2 is suitable as clean fuel. The pyrolysis gas produced, however, is insufficient to provide the fuel requirement for the total plant. Residual char, 50—60% of the feed coal, has a heating value and sulfur content about the same as feed coal, and its utilisation may thus largely dictate process utdity. 

If the substitute fuel is of the same general type, eg, propane for methane, the problem reduces to control of the primary equivalence ratio. For nonaspiring burners, ie, those in which the air and fuel suppHes are essentially independent, it is further reduced to control of the fuel dow, since the air dow usually constitutes most of the mass dow and this is fixed. For a given fuel supply pressure and fixed dow resistance of the feed system, the volume dow rate of the fuel is inversely proportional to. ypJ. The same total heat input rate or enthalpy dow to the dame simply requires satisfactory reproduction of the product of the lower heating value of the fuel and its dow rate, so that WI = l- / remains the same. WI is the Wobbe Index of the fuel gas, and... 

The results quantitatively show the signifieanee of eonsidering both boundaries of the unsteady state operation. The load required at the end of the eyele is less than one-half the load required at the start of the eyele. Steve [13] inferred that reporting the value at only one boundary may be misleading. For example, the total heat load (provided by ehillers and heaters) from multiple reaetors with overlapping temperature adjustment eyeles may be skewed if the ehanges within those eyeles are not eonsidered. 

The thermal flux recorded by a radiometer 50 m from the vessel is shown in Figure 6.7 it indicates a peak value of 66 kW/m. The total heat dosage at this point was 115 kJ/m, and the duration of the fireball was about 4 seconds. 

H = total heat transfer rate, BTU/hr. For heat exchangers. Ref [33a] recommends that this value be taken as the maximum exchanger duty during operation. 

This references to the total heat of combustion of a flame and selected values are [57, 33C] ... 

Figure 8-60 presents actual total heats of absorption based on experimental studies [32]. As long as the hydrocarbon absorption is in the range of 80-120°F, the values read from the graph should apply. 

Calculate the total heat transferred to the process fluid check against the required value. The adjustments required may result in a new exchanger configuration and a new calculation of circulation rate. 

The specific enthalpy (or total heat) of the mixture can be taken from 0 K (- 273.15°C) or from any convenient arbitrary zero. Since most air-conditioning processes take place above the freezing point of water, and we are concerned mostly with differences rather than absolute values, this is commonly taken as 0°C, dry air. For conditions of 25°C, saturated, the specific enthalpy of the mixture, per kilogram of dry air, is... 

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