Generalized degree of reduction

The next difficulty in using the energy balance is that thermodynamic property data, such as the heat of combustion, may not be known for some identified molecular species compounds, and is not likely to been measured for incompletely defined species such as the average biomass CHi.sOo.sNo.t- To estimate the properties in these cases, we will use the generalized degree of reduction, - c. defined as follows ... 

The average biomass used to represent many yeasts and bacteria has an elemental composition, on a C-moIe basis, of CH. sOo.5No.2. Compute its generalized degree of reduction, and estimate its Gibbs energy and heat of combustion. 

It is useful to compare this answer with the more approximate one that is obtained using the generalized degree of reduction for all components ... 

There is one linear combination of the carbon, nitrogen, and oxygen balances that is especially useful. If we take the sum of four times the carbon balance plus the hydrogen balance and subtract twice the oxygen balance (note that the multipliers are the valences, and are the same numbers that appear in the definition of the generalized degree of reduction), we obtain... 

It is of interest to examine the simplified version of the second-law constraint in terms of the generalized degrees of reduction. In this case we have... 

To begin, we compute the generalized degree of reduction of the biomass produced ... 

Table 4 Kharasch and generalized degree of reduction definition for ammonia and biomass.

Calculation of the degree of reduction and generalized degree of reduction was presented in equations (22) and (25), respectively. The low value of the atomic coefficient of sulfur in biomass has a low influence on the degree of reduction. 

Table 9 Elemental analysis of microorganisms. Mass fractions are expressed as g per 100 g biomass. Mx is the mass of one C-mole of biomass, and y the generalized degree of reduction. The standard deviation is indicated in parenthesis [37,38]. 

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