NATURAL GAS SAVING BY REPLACEMENT THE LAST FOR PROCESS GASES WHILE HEATING MIDDLE AND HIGH TEMPERATURE FURNACES. PART 2. NUMERICAL DETERMINATION OF FUEL FLOW RATE, OF FUEL USE ENERGY AND ENVIRONMENTAL CHARACTERSTICS BY ASSIGNMENT OF FUEL TYPE AND COMPOSIT

Abstract

The technique for calculation of need fuel flow rate and for proper combustion heat flow has been advanced in frame of new author’s (B.S. Soroka) methodology of fuel replacement that takes the second law of thermodynamics into account along with the first law. Method for calculation the rate of available enthalpy flow of fuel-oxidant mixture has been developed. An impact of fuel replacement on formation the harmful substances by gas fuels combustion in the furnaces has been studied. The concept of new approach to interchangeability of fuel gases is grounded upon condition of conservation the rate of useful total enthalpy flow under fuels substitution. The last value accounts the fuel use efficiency. Numerical calculations of saving or over expenditure the natural gas (NG) for the cases of total or partial NG substitution by process gases have been fulfilled. The calculations of the available heat flows of fuel-oxidant mixture and of combustion heat flow of the analyzed low-calorific fuels have been carried out for the cases of NG replacement with the process gases depending on the content (volume fraction) of blast furnace gas (BFG) in mixtures with natural (NG + BFG) or coke oven (COG + BFG) gases. Evaluation of formation and of specific effluents of pollutants: carbon dioxide N²CO2 as a greenhouse gas and nitrogen oxides C²NOx as the most representative harmful substance — has been carried out along with computations of fuel flow rate and with energy using characteristics of low calorific mixed fuels. Bibl.12, Fig. 7, Tab. 2.