Methane specific heat

The specific heats of IPN product gas (primarily carbon monoxide and methane) arising from combustion are Cp 0.333cal/g/° and Cv 0.246cal/g/° (both calcd at 250psi and 300°K). The specific impulse of these gases (calcd at 400psi) is 155 lbs/thrust/lb/sec... 

Example 3.4 A turbulent fire plume is experimentally found to bum with 10 times the required stoichiometric air up to the tip of the flame. It is also measured that 20 % of the chemical energy is radiated to the surroundings from the flame. The fuel is methane, which is supplied at 25 °C and burns in air which is also at 25 °C. Calculate the average temperature of the gases leaving the flame tip. Assume constant and equal specific heats and steady state. 

Uddin et al. (2008b) conducted several depressurization simulations for the Mallik 5L-38 well. Their results showed that the Mallik gas hydrate layer with its underlying aquifer could yield significant amounts of gas originating entirely from gas hydrates, the volumes of which increased with the production rate. However, large amounts of water were also produced. Sensitivity studies indicated that the methane release from the hydrate accumulations increased with the decomposition surface area, the initial hydrate stability field (P-T conditions), and the thermal conductivity of the formation. Methane production appears to be less sensitive to the specific heat of the rock and of the gas hydrate. 

Typically, ATR reactions are considered to be thermally self-sustaining and therefore do not produce or consume external thermal energy. In fact, since ATR consists of the combination of an exothermic reaction (CPO) which produces heat, with an endothermic reaction (CSR) where heat must be externally generated to the reformer, the balance of the specific heat for each reaction becomes a very distinctive characteristic of this process. This makes the whole process relatively more energy efficient since the heat produced from CPO can transfer directly to be used by CSR. However, other exothermic reactions may simultaneously occur, such as WGS and methanation reactions. 

Salt Specific heat Percentage ignition of methane... 

These figures show that a high specific heat is not correlated with inhibition of explosion of methane. E.g. the high specific heat of ammonium chloride does not help this salt to inhibit methane explosions. 

The calculation of the flame temperature for a combustible gas like hydrogen, carbon monoxide, or methane at first sight appears to be a simple problem since the apparently necessary data are only the heat of combustion and the specific heats of the products. Such calculations always yield very high results much above those recorded by direct experimental measurements. The discrepancy is probably due to a combination of several causes. On account of the temperature of the flame the products are partially dissociated,1 so that combustion is not complete m the flame. The specific heat of gases increases with rise m temperature, so that the value obtained at the ordinary temperature for the specific heat is too low. In addition to these two causes, another contributory factor is the loss of heat by radiation, which may be very considerable even m nou-lummous flames, whilst the general presence of an excess of the supporter of combustion and the non-instantaneous character of the combustion also detract from the accuracy of the calculation.2... 

The fact that the lower limit of methane is greater in the case of pure oxygen than with air is piobably connected with the fact that the specific heat of oxygen is higher than that of air. 

The free energies of formation and heats of formation for the oxides of lead are given by Millar8U as shown in Table X. The specific heat of methane is given as C, =r 7.5 -f- 0.005 T,Hr ... 

From what has been said above it is clear that free rotation will be most common in molecular structures which contain small molecules, and indeed a quantitative treatment reveals that it may be expected in many such structures below their melting points. In hydrogen, free rotation of the H2 molecule occurs at the absolute zero, and the crystal structure down to the lowest temperature at which it has been observed is hexagonal close packed. In methane, rotation sets in at about 20 °K, and the transition is accompanied by an anomalous increase in specific heat between 18 and 22 8 °K. Above the latter temperature the structure is cubic close packed. Similar transitions take place in HC1 and HBr, the high-temperature forms of which have close-packed structures while at low temp eratures more complex structures of lower symmetry obtain. F ree rotation is naturally less common in molecular structures containing large molecules, but it is found in certain long-chain compounds, to be discussed later, in which rotation about the axis of the chain takes place ( 14.22). 

The same group [2.354] has also recently reported on the performance of a membrane reactor with separate feed of reactants for the catalytic combustion of methane. In this membrane reactor methane and air streams are fed at opposite sides of a Pt/y-A Os-activated porous membrane, which also acts as catalyst for their reaction. In their study Neomagus et al. [2.354] assessed the effect of a number of operating parameters (temperature, methane feed concentration, pressure difference applied over the membrane, type and amount of catalyst, time of operation) on the attainable conversion and possible slip of unconverted methane to the air-feed side. The maximum specific heat power load, which could be attained with the most active membrane, in the absence of methane slip, was approximately 15 kW m with virtually no NO emissions. These authors report that this performance will likely be exceeded with a properly designed membrane, tailored for the purpose of energy production. 

In this problem, we correlate the specific heats of normal alkanes from Cl to Ce with the number of vibrational degrees of freedom. Locate the appropriate coefficients that describe empirically the temperature dependence of the specific heat for normal alkanes from methane to n-hexane. The polynomial expression can be written genericaUy in the form... 

If 42.0 kj of heat is added to a 32.0-g sample of liquid methane under I atm of pressure at a temperature of —170 °C, what are the final state and temperature of the methane once the system equilibrates Assume no heat is lost to the surroundings. The normal boiling point of methane is —161.5 "C. The specific heats of liquid and gaseous methane are 3.48 and 2.22 J/g-K, respectively. [Section 11.4]... 

CALCULATION OF THE SPECIFIC HEAT OF THE VAPORS OF HALOGEN SUBSTITUTED MONOSILANE AND METHANE. 

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