LHV calculation of mixed fuel gas (ASME PTC-22)

ASME Performance Test Codes (PTC 22) establishes directions and rules for the conduct and results reporting of thermal performance tests for open cycle gas turbine power plants and gas turbine engines. This performance test code provides explicit instruction on determining corrected power, heat rate (efficiency), exhaust flow, exhaust energy, and exhaust temperature. 

Guidance is also provided for designing testing requirements and programs to satisfy different goals such as absolute performance and comparative performance.

Introducing the fuel heating value table introduced here.
The procedure for calculating the mixed fuel gas LHV is written in Python as follows.

Run Python code below : https://www.mycompiler.io/view/41iScgW4CFz

dbHC = [# Formula, Molecular Weight [lb/lbmol], Standard Density [lb/1000 ft3], High Heating Value [Btu/lbm], Low Heating Value [Btu/lbm]
       ["CH4", 16.0425, 42.274, 23892.2, 21511.9],
       ["C2H6", 30.0690, 79.237, 22334.1, 20429.2],
       ["C3H8", 44.0956, 116.199, 21654.1, 19922.2],
       ["C4H10", 58.1222, 153.161, 21232.3, 19589.8],
       ["C4H10", 58.1222, 153.161, 21300.2, 19657.8],
       ["C5H12", 72.1488, 190.123, 21043.7, 19455.9],
       ["C5H12", 72.1488, 190.123, 21085, 19497.2],
       ["C6H14", 86.1754, 227.085, 20943.8, 19392.9],
       ["C7H16", 100.2019, 264.048, 20839.1, 19314.7],
       ["C8H18", 114.2285, 301.010, 20759.7, 19255.4],
       ["C9H20", 128.2551, 337.972, 20701, 19212.3],
       ["C10H22", 142.2817, 374.934, 20651.6, 19175.5],
       ["CO", 28.0101, 73.811, 4342.2, 4342.2],
       ["CO2", 44.0095, 115.972, 0.0, 0.0],
       ["H2S", 34.0809, 89.808, 7094.1, 6533.8],
       ["Air", 28.9651, 76.328, 0.0, 0.0],
       ["H2", 2.0159, 5.312, 61022.3, 51566.7],
       ["O2", 31.9988, 84.322, 0.0, 0.0],
       ["N2", 28.0134, 73.820, 0.0, 0.0],
       ["H2O", 18.0153, 47.473, 1059.8, 0.0],
       ["He", 4.0026, 10.547, 0.0, 0.0],
       ["Ar", 39.9480, 105.269, 0.0, 0.0],
       ]

def hclhv(Comp):

    n = len(dbHC)
    sumComp = sum(Comp)
    for i in range(n):
        Comp[i] = Comp[i] / sumComp

    sumLHV = 0
    for i in range(n):
        LHV = dbHC[i][4] * dbHC[i][1] / ((10.7316*519.67) / 14.696)
        sumLHV = sumLHV + Comp[i] * LHV
    sumComp = sum(Comp)

    return sumLHV / sumComp

Comp = [90, 4, 2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0]
print("Mixed Fuel Gas LHV [Btu/Scf] = ", hclhv(Comp))

When run the code, you get the results below.

Mixed Fuel Gas LHV [Btu/Scf] =  959.622