Compressor Calculations Rigorous Using Equation of State vs Shortcut Method. In this tip of the month TOTM we will present the compressor calculations of a case study. We will compare the rigorous method results with the values from the short cut methods. The rigorous method is based on an equation of state like the Soave Redlich Kwong SRK for calculating the required enthalpies and entropies. The enthalpies and entropies are used to determine the power requirement and the discharge temperatures. The results indicate that the accuracy of the shortcut method is sensitive to the value of heat capacity ratio, k. Power Calculations. The theoretical power requirements are independent of compressor type the actual power requirements vary with the compressor efficiency. In general the power is calculated by where  mass flow rate and h is specific enthalpy. From a calculation viewpoint alone, the power calculation is particularly sensitive to the specification of flow rate, inlet temperature and pressure, and outlet pressure. Gas composition is important but a small error here is less important providing it does not involve the erroneous exclusion of corrosive components. A compressor is going to operate under varying values of the variables affecting its performance. Patch Chrono Trigger Ds Changes. Thus the most difficult part of a compressor calculation is specification of a reasonable range for each variable and not the calculation itself. PC-Cleaner-Pro-2015-License-Key-Crack-Key-Full-Download.png' alt='Promax Software Cracked' title='Promax Software Cracked' />Reference 1 emphasizes that using a single value for each variable is not the correct way to evaluate a compression system. Normally, the thermodynamic calculations are performed for an ideal reversible process. The results of a reversible process are then adapted to the real world through the use of an efficiency. In the compression process there are three ideal processes that can be visualized 1 an isothermal process, 2 an isentropic process and 3 a polytropic process. Any one of these processes can be used suitably as a basis for evaluating compression power requirements by either hand or computer calculation. The isothermal process, however, is seldom used as a basis because the normal industrial compression process is not even approximately carried out at constant temperature. For an isentropic reversible and adiabatic process, equation 1 can be written as and based on the polytropic process The isentropic head is calculated by equation 3. A Similarly, the polytropic head is calculated by equation 3. B The actual discharge temperature based on the isentropic path is calculated by equation 4. In this tip of the month TOTM we will present the compressor calculations of a case study. We will compare the rigorous method results with the values from the. Crack software download PolyWorks v2015 ASA OILMAP v6. Dolphin Imaging v11. SPEAG SEMCAD X Matterhorn v15 Win. From millions of real job salary data. Average salary is Detailed starting salary, median salary, pay scale, bonus data report. A. The actual discharge temperature based on the polytropic is calculated by equation 4. B. where and P are the isentropic or adiabatic and polytropic efficiency, respectively, P1 suction pressure, P2 discharge pressure, T1 and T2 arethe suction and discharge temperatures, respectively, q is gas volume flow rate at standard condition of PS and TS, Za average gas compressibility factor, k heat capacity ratio, R the gas constant, and n is the polytropic path exponent. Equations 1 and 2 are equally correct theoretically. The practical choice depends on the available data, although it is somewhat arbitrary. The power calculation should be made per stage of compression and then summed for all stages connected to a single driver. REPEATER-MODE-500x280.png' alt='Promax Software Cracked' title='Promax Software Cracked' />For general planning purposes the graphical solutions shown in reference 2 produce results comparable to these equations. Equation of State EOSThe heart of any commercial process flow simulation software is an equation of state. Due to their simplicity and relative accuracy, normally a cubic EOS such as Soave Redlich Kwong SRK 3 or Peng Robinson 4 is used. These equations are used to calculate phase behavior, enthalpy, and entropy. With proper binary interaction coefficients, the process simulation results of these two equations are practically the same. Therefore, only the SRK was used in this work. Step by Step Computer Solution. For known gas rate, pressure P1, temperature T1, and composition at the inlet condition and discharge pressure P2, computation of compressor power requirement is based on an EOS using a computer and involves two steps Determination of the ideal or isentropic reversible and adiabatic enthalpy change of the compression process. The ideal work requirement is obtained by multiplying mass rate by the isentropic enthalpy change. Adjustment of the ideal work requirement for compressor efficiency. The step by step calculation based an EOS is outlined below. FMP/4W8L/GDVZ315T/FMP4W8LGDVZ315T.LARGE.jpg' alt='Promax Software Cracked' title='Promax Software Cracked' />Assume steady state, i. Assume isentropic process, i. Calculate enthalpy h. P1, T1, and composition and suction entropy s. P1, T1, and composition at the suction condition by EOSFor the isentropic process. Note the represents ideal value. Calculate the ideal enthalpy at outlet condition for known composition, P2 and. The ideal work is The actual work is the ideal work divided by efficiency or The actual enthalpy at the outlet condition is calculated by The actual outlet temperature is calculated by EOS for known h. P2, and composition. The efficiency of the compressor, and hence, the compression process obviously depends on the method used to evaluate the work requirement. The isentropic efficiency is in the range of 0. If the compressor head curve and efficiency curve are provided by the manufacturer,  the head is determined from the actual gas volume rate at the inlet condition. Second, from the head, the actual work, discharge pressure and finally the discharge temperature are calculated. Case Study. The gas mixture with the composition shown in Table. F 4. 0. 6 C and 1. Psia 7. 93 k. Pa is compressed using a single stage centrifugal compressor with the polytropic head and efficiency curves shown in Figures 1 and 2 at a speed of 7. The total feed gas volumetric flow rate was 1. MMSCFD 2. 8. 61. Sm. Table 1. Feed gas analysis. Figure 1. Compressor polytropic head and best efficiency point. Figure 2. Compressor polytropic efficiency. Results and Discussions. SRK Rigorous Method The feed composition, temperature, pressure, volumetric flow rate at standard condition along with the compressor polytropic head and efficiency curves data were entered into the Pro. Max  software 5 to perform the rigorous calculations based on the SRK EOS. The program calculated polytropic and isentropic efficiencies, heads, compression ratio discharge pressure, discharge temperature and power. For the actual gas flow rate at the inlet condition, the polytropic efficiency is close to the compressor best efficiency point BEP. The program also calculated the gas relative density, heat capacity ratio k, and polytropic exponent n. These calculated results are presented in the SRK columns of Table 2 bold numbers with white background. Table 2. Summary of the rigorous and shortcut calculated results. The bold numbers with white background are the calculated values. Short 1 Shortcut Method In this method, we used equations 2 through 4 to calculate the polytropic and isentropic heads, the discharge temperature and power. We used the Pro. Max calculated polytropic and isentropic efficiencies, compression ratio P2P1, heat capacity ratio k and polytropic exponent n to calculate head, power, and the discharge temperature. The results are presented in the short 1 columns of Table 2. Note the short 1 results discharge temperature, adiabatic and polytropic heads and power are very close to the SRK values. The calculated actual discharge temperature by equation 4.