Different methods such as gas density graphs, Joule-Thomson expansion, empirical equations, statistical thermodynamics and artificial neural networks have been proposed to predict gas hydrate formation conditions (pressure or temperature). The best way to determine hydrate formation conditions is empirically measured using temperature, pressure and gas composition parameters, but since empirical measurements are impossible due to time and cost. The hydrate formation conditions for any given gas are not empirically feasible .
In gas samples collected from the closed oil dug wells, methane, ethane, propane, i-butane, i- pentane, n-pentane and carbon dioxide were de- tected. Methane was found in all of the analyzed samples, in concentrations from 0.8 to 1220 ppm with arithmetic mean 125.4 ppm and median val- ue 3 ppm. Ethane was detected in almost 42% of analyzed samples in concentrations up to 3.62 ppm (arithmetic mean – 0.4 ppm). Propane was ob- served in almost 17% of the analyzed samples. Its concentrations reached up to 3.5 ppm with arith- metic mean 0.32 ppm. Maximum concentrations of i-butane and n-butane were 0.77 and 0.65 ppm, respectively, and were observed in almost 17% of the analyzed samples. Neo-pentane has not been detected whereas i-petane and n-pentane were ob- served in about 17% of the analyzed samples, but in amounts below 0.5 ppm. The concentrations of carbon dioxide varied from 0.07 to 0.22 vol.% with the arithmetic mean 0.14 vol.% (Table 2) .
 Sudharash Bhargava and Jagdev Singh, “Experimental study of azeotropic blend(30% propane, 55% n-butane, 15% iso-butane) refrigerant flow through the serpentine capillary tube in vapour compression refrigeration system”, International Journal of Mechanical and Production Engineering Research and Development, 2013.  Thamir K. Salim, “The effect of the capillary tube coil number on the refrigeration system performance”, Tikrit Journal of
Methyl tertiary butyl ether (MTBE) is the most common oxygenate added to gasoline in the United States. However, other ether-based oxygenates including ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), and di-isopropyl ether (DIPE) are also used to a lesser but growing extent. In this study we have characterized features of the cometabolic degradation of ETBE, TAME and DIPE by Mycobacterium vaccae JOB5. Oxidation of both ETBE and TAME occurred without a lag phase with propane-grown cells while no oxidation of either compound was observed with dextrose-grown cells. Acetylene, a mechanism based inhibitor of the propane-induced alkane-oxidizing monoooxygenase, fully inhibited these two reactions. In addition, the oxidation of both ETBE and TAME was inhibited by propane. M. vaccae JOB5 cells grown on n-butane, n- pentane or isopentane also rapidly oxidized ETBE and TAME. In contrast to ETBE and TAME, we did not observe detectable rates of DIPE oxidation under any of the
Using the computational details described above, free energy of solvation calculations were carried out in a cubic box in inﬁnite dilution for two separate systems: (i) 596 TIP3P water molecules and 1 OPLS-AA alkane (methane, ethane, propane and n-butane) molecule (ii) 354 OPLS-AA methanol and 1 OPLS-AA alkane (methane, ethane, propane and n-butane) molecule. The free energy of solvation of alkanes in diﬃerent solvent environments, water and methanol were estimated by Eq.(14). The extent to which Hamiltonian of the system has been perturbed is measured by the free energy change of transforming a system from state A (λ = 0) to state B (λ = 1), ∆A, as a function of a coupling parameter, λ. For decoupling van der Waals interactions, we used an equidistant λ spacing of 21 diﬃerent λ’s from 0 to 1. Thus, the free energy change from λ = 0 to λ = 1 is simply the sum of the free energy changes of each pair of neighboring λ simulations. The free energy changes of each pair of neighboring λ and the cumulative free energy change which is negative of free energy of solvation of butane in water is shown in ﬁgure (3).
approach ideal behavior at high temperature and low pressure, and the isenthalps correspondingly become flat. The shape of the Joule-Thomson inversion curve of a fluid at high temperatures is shown to be directly related to its second and third virial coefficients. The intersection with the temperature axis (the low-pressure limit at high temperatures) marks a point where the tangent to the second virial coefficient passes through the origin, i.e. dB/dT=B/T. The agreement between the calculated and experimental data is excellent on the low temperature side. Unfortunately, due to lack of isenthalpic data for high-pressure-high- temperature gas condensate for water and methanol, the reliability of model predictions could not be completely verified. The average absolute error for the lower-pressure isobar is 1.5% for water and 1.2% for methanol.
is essential to compensate for measured fully developed downstream temperature and consequently correct for flow measurement. The accuracy of such measurement with respect to pressure drop is characterized by Joule - Thomson effect in . The study presents a procedure to enable the compensation of Joule - Thomson effect in natural gas flow-rate measurements. It has been derived in  a numerical procedure for the calculation of the natural gas specific heat capacity, the isentropic exponent, and the Joule - Thomson coefficient that can be used to compensate for the adiabatic expansion effects in real - time flow rate measurements. The results showed that the procedure can be efficiently applied in both off-line calculations and real time measurements. The effect of a Joule - Thomson expansion on the accuracy of natural gas flow rate measurements was pointed out in . The study investigated the computationally intensive procedure for the precise compensation of the flow rate error, caused by the Joule - Thomson expansion effects. In the present study methane gas is the adopted fluid and the uncertainty Joule - Thomsoncoefficients at different operating pressures for methane are extracted from experimental figures in . Joule - Thomson coefficient equation has been reported in EN ISO 5761 standard and the temperature reduction is assigned only with fully developed flow at 5D to 15D downstream the orifice . Hence the maximum
A third order virial equation was usually used or second order one if it describes data correctly. To ensure that select order of virial equation describes data set correctly without significant influence of higher virial coefficients, the regression residuals were checked if they do not exceed the standard deviation of measurement uncertainty. If the third order virial equation failed this test the data set was reduced on a side of high density or pressure respectively and checked again.
sociation of propane and butane molecules. The data confirm that the dissociation processes occurs mainly near the cathode. The mean energy of the electrons in the discharge is much higher near the cathode rather than near the anode . Also the spark discharge spots, formed on the cathode, elevate the propane and butane molecules temperature, which in turn enhances the thermal dissociation processes of propane and butane molecules. The resultant species (atoms, molecules and radicals) from the dissociation processes diffuse in all directions and hence their densities near the anode are too low to be detected in the measured spectrum.
Determination of hydrocarbon elution times : Separate standard atmospheres of methane, ethane, butane, pentane and isoprene and mixed standards were prepared as described earlier; furthermore, 1ml of each standard was injected directly into the gas chromatograph, and retention time of each analyte, independently and with respect to internal standard (butane) was obtained. Moreover, peaks of mixed standards and breath samples were identified according to their retention times.
The predicted Amagat curve lies at significantly higher pressure than the Frenkel line (over 3x the pressure of the Frenkel line at 300 K). The prediction of the Amagat curve, just like that of the Boyle curve and Joule-Thomson curve, stems from an understanding of the supercritical fluid state as a dense non-ideal gas. We argue, therefore, that the predicted Amagat curve is not meaningful on account of the fact that it lies at significantly higher pressure than the Frenkel line. In this P-T region we propose that the fluid must be treated as a solid in which the molecules are relatively closely packed with specific positions and only occasional vacancies.
In view of the foregoing, researches of water and oil emulsion divisions were conducted by means of initial and plasma treated membranes with the pore size of 50 kDa, which were made from polyacrylonitrile (PAN). The treatment was done by low temperature HFC plasma of low pressure in the atmosphere of argon and nitrogen (hydrophilous regime) and propane and butane (hydrophobous regime) in the ratio 70:30 in accordance with the following conditions: current intensity on anode is (I а ) –
displayed. After those there can be a number of CFHX segments until segment N, which is displayed again. This last segment is connected to the cold tip (here it is labelled ‘Evaporator’). The block labelled ‘Massflow’ has an input of the temperature of the ‘Evaporator’ and an output to every other block in the system. As an example the contents of ‘Massflow’ (figure 2) and the ‘Evaporator’ (figure 3) are shown below. The conductive heat flows into ‘Evaporator’ are denoted with Qc. They are added to the enthalpy flow off the fluid from the high-pressure channel after the fluid has passed the restriction (‘JT expansion’). The minus sign in the ‘Add’ block is for the enthalpy flow out of the ‘Evaporator’ into the low-pressure channel. The temperature of the ‘Evaporator’ is used for calculating this enthalpy flow and also for the radiative heat flow and the heat capacity. Since
Comparison of the results obtained during processing of propane-butane and propane- propylene mixtures over the Zn-La-Fe-ZSM-Al 2 O 3 catalyst shows that the composition of the feedstock practically does not affect the conversion. The amount of aromatic hydrocarbons formed is higher when using a propane-propylene mixture. At a temperature of 550 0 C, the yield of the liquid products
Pada masa kini, teknologi aerosol semakin berkembang pesat di mana penyelidikan dan pembangunan tertumpu kepada analisis propellant, pembungkusan dan bahan-bahan untuk membuat aerosol supaya produk yang dihasilkan berkualiti tinggi. Walau bagaimanapun, terdapat beberapa masalah utama dalam peghasilan penyemburan aerosol produk, seperti pengeluaran VOC dan masalah kualiti proses penyemburan. Oleh itu, dalam kajian ini, ciri-ciri semburan telah dikaji dengan menggunakan kaedah simulasi CFD dalam penghasilan rekabentuk nozzle. Analisis tertumpu pada pelbagai tekanan; sehingga 9bar, di mana n-butane dan air digunakan sebagai bahan fasa cecair. Simulasi dilakukan berdasarkan dua jenis reka bentuk nozzle yang dipilih. Hasil daripada kajian menunjukkan bahawa, nilai halaju, nilai