Specific heat hydrocarbon liquids

The specific heat of natural gas and hydrocarbon liquids can be calculated using procedures described later in this text (see pp. 41 and 42). 

The specific heat of hydrocarbon vapors and liquids is given by Figures 2-13 and 2-14. 

According to Schiff o the specific heats of organic liquids in homologous series are either equal or change per saltum and are expressible by an equation of the form Cp=a+bt in which b has a constant value. Esters of fatty acids (C/ H2 02) have the specific heat 0 4416+0 0388/, and aromatic hydrocarbons from benzene to xylene 0 3334+0 021043/, etc. These results were confirmed by Herz.ii... 

Since domestic water heaters are required to deliver their output at only 140°F, the availability efficiency of such a unit is, of course, much lower than 40%. If the heater is fueled by a hydrocarbon, then = 1.0 and the quality, C2, can be calculated by the expression for liquids or solids having near-constant specific heat that is,... 

Some factors that influence the rate of evaporation of a solvent include temperature, flow of air over sample, vapor pressure of the solvent, latent heat, specific heat, and molecular weight (53). Galstaun (55) in 1950 reported a thorough study of the evaporation of some hydrocarbon solvents and developed equations for evaporation rates as related to several factors including temperature drop of liquid as it evaporates. Sletmoe (56) developed equations for the evaporation of neat solvent blends. The total rate of evaporation was proposed to be equal to the sum of the rates for the individual solvent components ... 

Thermal Properties of Nitration Acids. Heals of Solution. To determine the heat evolved during the actual process of nitration of a hydrocarbon by mixed acids, it is necessary to consider not only the heat of nitration but also various heats of solution. These may be obtained from the enthalpy chart developed by McKinley and Brown (Fig. 4-5). For each of the three components, the enthalpy is taken as zero at the standard state, consisting of the pure liquid component at a temperature of 32 F and a pressure of 1 atm. Plotted against the same abscissa but against different ordinates are the specific heat data for the system. From this figure, containing both 32 F relative enthalpies and specific heats, the enthalpy of any liquid mixtures of these components at ordinary temperatures can be readily calculated by reading the desired relative enthalpy at 32 F and the specific heat from the chart. 

The fluid properties for the three processes may be considerably different. The CCC process uses a low pH solution (containing water and the acid product) whereas both DCL and FTS use hydrocarbon like liquids. Physical properties such as surface tension, viscosity, specific heat and thermal conductivity for these two cases may be quite different. Since the FTS is a very energetic process, the reactor may also contain some internals such as heat exchangers (cooling coils) etc. Some physical and thermal properties for these systems are outlined in Table 2. 

How many pounds of heavy hydrocarbon liquid must be vaporized to cool 700,000 Ib/hr of vapor from 980°F to 630°F Assuming a specific heat of 0.6 for the vapor and a latent heal of vaporization of 90 BTU/lb for the cycle oil ... 

By solving the differential equation we find that in the falling time of 1 s, the temperature difference is 0.75. 120 = 90 K. When the liquid had been a hydrocarbon, with a much lower specific heat, the temperature difference would have been approximately 115 K. The data used in this calculation are for water (C p), = 4.2. 10 J/m K, for liquid hydrocarbons this is about 1.5. 10 J/m K. 

Hot Removal, Advanced systems that perform hot acid gas removal are still under development (27,28,29). These systems are generally aimed specifically at power generation applications. Their primary advantage is their ability to avoid all or most of the coal gasification heat recovery steam generation. In addition, hot H2S removal could avoid the need to remove and process water vapor and light hydrocarbon liquids in the... 

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