Unformatted text preview: EML 5104 Classical Thermodynamics, Spring 2010 Use as cover sheet Name (Print): ___________________________________ UF
ID: ___________________________________ Homework Week 11 Due March 28 at the begin of class P1: The mass fractions of carbon, hydrogen, oxygen, and sulfur in Lignite are 0.60, 0.06, 0.33, and 0.01 respectively. a) The equivalent chemical formula of Lignite is CHxOySz. Calculate the numerical values of x, y, and z. b) Calculate the theoretical amount of air in mol O2 per mole equivalent of Lignite. c) The higher heating value (HHV) at 298 K is 28’470 kJ/kg. Calculate the enthalpy of formations of Lignite in kJ per mole equivalent. d) Give the contribution (in %) of sulfur combustion to the HHV. e) SO2 has to be removed from the flue gases. How could this be done? f) Assume that SO2 can be modeled as an ideal gas. Use specific heat information given in Table A
21 (Moran and Shapiro, on EDGE) to create tabular data of ideal gas specific enthalpy, internal energy, and reference specific entropy for temperatures between 298 K, and 1000 K at 10 K intervals (use a computer). g) Assume that Lignite can be modeled as an incompressible substance with a constant specific heat of 1 kJ/(kg K) and calculate the adiabatic flame temperature for combustion with 500 % theoretical air. Inlet conditions are reference conditions. h) Lignite is burned in a steam generator with 200 % theoretical air. Combustion products enter at reference conditions and flue gases leave at 398 K, 1 bar. Water enters as compressed liquid at 353 K, 40 bar and leaves as saturated steam at 40 bar. Calculate the mass flow rate of water if 1 kg of Lignite is burned per second. i) Calculate the rate of work lost in the arrangement described in e) j) Do you have sufficient information to calculate the adiabatic flame temperature for combustion with theoretical air. If yes, calculate the adiabatic flame temperature. If no, which information is missing? Give a literature source for the missing information. k) What is the maximum amount of work that can be produced from 1 kg of Lignite at 298 K. Assume that the surroundings are at reference conditions. Hint: use ideal gas properties for all gases ...
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