Graph Model for Carbon Dioxide Emissions from Metallurgical Plants

Abstract

The emission of carbon dioxide -a greenhouse gas -is adversely affecting the environment regionally, nationally, and globally, and some scientists believe that it is changing the world's climate. Evaluating such emissions is an important part of the search that is going on to find the technologies which are the best from the standpoint of emitting the least amount of this gas. Evaluating carbon-dioxide emissions is also important for determining the penalties that factories should be assessed for exceeding established emission limits.A carbon footprint is the analog of an emission of carbon dioxide. The carbon footprint is greater than this emission because it is determined with allowance for the effect of other greenhouse gases. However, metallurgical plants produce larger volumes of carbon dioxide than any other greenhouse gas -carbon dioxide is formed during the oxidation of the carbon in different types of fuel during a factory's operation. We will designate the total amount of carbon dioxide emitted in this manner as M G and we will refer to it as the integral emission from the operation of the plant (it is being called "integral" because it characterizes the emission of the factory as a whole). For example [1], a blast furnace operated without the injection of natural gas forms blast-furnace gas having the following composition: 12-18% CO 2 ; 24-30% CO; 0.2-0.5 CH 4 ; 1.0-2.0% H 2 ; 55-59% N 2 . The heat of combustion of blast-furnace gas is 3500-4000 kJ/m 3 . Blast-furnace gas having the following composition is formed when the blast air is enriched with up to 30% oxygen and natural gas is also injected into the furnace: 15-22% CO 2 ; 22-27% CO; 0.2-0.5% CH 4 ; 8-11% H 2 ; 43-45% N 2 . This blast-furnace gas has a heat of combustion of 4200-5000 kJ/m 3 . Some of the gas is burned in the stoves of blast-furnaces, but most of it is burned in heating furnaces, municipal electric power plants, or flares. A similar pattern of use is seen in the case of residues of coke-oven gas that do not undergo combustion in coke-oven batteries. Natural gas is currently being widely used in heating furnaces. In light of this, all of the carbon dioxide that is formed by the combustion of coke and injected gas in blast furnaces at a metallurgical plant is included in models of the smelting operation. A similar assumption is made for coke-oven batteries.We further assume that the power plant of an integrated metallurgical plant supplies energy to all of the metallurgical plant's furnaces. It was reported in [2] that 90% of a metallurgical plant's energy needs are met by the output of its own power plant. Thus, in the graph models that have been constructed, electric power is obtained from outside networks only to make oxygen and operate the metallurgical plant's electric-arc furnaces.

The greenhouse index of sustainable development for metallurgical processes of production in aspect of green power

“…The technique and formulas for calculation of through emission of carbon dioxide are given in works [6][7][8][9][10].…”

Analysis of Energy Content and CO2 Emissions in Different Combinations of Coke-Using and Coke-Less Processes for Steel Production

“…A graph such as that in Fig. 1 is used calculate end-to-end emissions of CO 2 [6,7]. Some of the vertices in the graph's ovals show values of end-to-end CO 2 emissions per unit of production.…”

“…Thus, the TGN is equal to the weight of the comparison fuel required to offset the cost associated with the economic loss from greenhouse-gas emissions per unit of production. Using models that are in the form of graphs [6,7], we can calculate the end-to-end value of the TGN for a specifi c product (such as pig iron) from the values of the TGN in the preceding conversions with allowance for their weight fractions Ψ ij m (which are represented as the weights of arcs):…”