Ethylene is the largest single chemical commodity in the world. It is the precursor for polyethylene, the most common form of plastic. One method for producing ethylene is to "crack" ethane using high temperature steam. C2H6→C2H4+H2 C 2 H 6 → C 2 H 4 + H 2 Successful cracking requires that the ethane reach a temperature of 800-900 [C]. Assume that pure ethane flows into a cracking unit at 75 [C] and that the fractional conversion of ethane in the unit is 80%, and that the outlet temperature is 800 [C]. How much heat is required to produce 1,000 [kg] of ethylene? Compare both the heat of reaction and heat of formation method. For this reaction, Δh∘r=137kJ/(molC2H4) Δ h r ∘ = 137 k J / ( m o l C 2 H 4 ) .
Ethylene is the largest single chemical commodity in the world. It is the precursor for polyethylene, the most common form of plastic. One method for producing ethylene is to "crack" ethane using high temperature steam. C2H6→C2H4+H2 C 2 H 6 → C 2 H 4 + H 2 Successful cracking requires that the ethane reach a temperature of 800-900 [C]. Assume that pure ethane flows into a cracking unit at 75 [C] and that the fractional conversion of ethane in the unit is 80%, and that the outlet temperature is 800 [C]. How much heat is required to produce 1,000 [kg] of ethylene? Compare both the heat of reaction and heat of formation method. For this reaction, Δh∘r=137kJ/(molC2H4) Δ h r ∘ = 137 k J / ( m o l C 2 H 4 ) .
Given reaction for cracking ethane is-
The temperature required for cracking is 8000C-9000C.
Temperature of pure ethane, T=750C
Fractional conversion of ethane, x= 80%=0.8
Outlet temperature, Tout=8000C
Mass of ethylene[C2H4] to be produced, m=1000 kg
Heat of reaction,
Hence, to produce 1 mol of ethylene (C2H4) 137 kJ energy is required.
Now, the molar mass of ethylene (C2H4)=28 g/mol=0.028 kg/mol
Hence, moles of ethylene is-
Further, since conversion of ethane ot ethylene is 0.8 so the moles of ethane entered is-
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