| OCR Text |
Show TABLE 'I COMPARISON OF COt\18USTIO!\J CCNTROLLABILITY Type of Coltrolled Chemical Reactions Cornbus-tion Gas/Air Burner Oxy-Fuel Burners Oxygen E'lriched .A.i r Burner PYRETRON x,CH4 + al x ,(02 +3.76N2) -- -- x 1C02 + 2xl H20 +a1x13.76N2 + + Cal -2)x10 2(Excess) + x1 q (Btu) x2CH4 + d2x 202 - - '2C02 + 2x2H20 + + (a2-2)x202(Excess) + x2q (Btu) X3CH4 + a3x302 + bX3(02+3.76N2) -- x3C02 + 2x3H20 + 3 . 75bx3N2 + T (a3+b- 2)x302(Excess) + + x3Q(Btu) Pyrolytic Zone x 4CH4 +a4x402+blx4(02+3.76N2)+ Oxygen Rich Zone +(X4CH4 +a'4x4 02+b2x~. (0,,+3. 76N2) ~ (x4+x~)C02 + 2(x4+~4)H20 + + 3.76(b1+ b2 )N2 + [x4(a~+bl-2) + + ~~(a4+b2-2)J02(Excess) - 1~4(Endothermic Pyrolysis) + + ~\I ) + ~1(Exothermic- 02 Rich Zone + Q4(Exothermic-Final Combustion) Controlled Parameters of Combustion Variables x l=f l (T,t) Constants al & Q Variables x2 = f(T,t) Constants a2 & Q Variables x3 = f 3 (T,t) Constants a3' b,&q (a3+b)/(a3+4.76b) (%Oxygen Enrichment) Variables x4 = f 4(T,t) x4 = fS(T,t) a4 f 6(T,t) b1 f 7 (T, t) a4 f 8(T,t) b2 fg(T,t) 0'4 f lO (T,t) Qg f 11 (T, t) Q4 f 12 (T,t) Constants Q Controlled Parameters of Heating Process Variables T = f 1(t) xl = f 2(t) Ql(Released) = xl Q 02(Excess) = f 3(al xj) Variables T = f,(t) x2 = f '2(T) Q2(Released) = x2Q 02(Excess) = f 3 (a2,x2) Variables T = f'; (t) x3 = f'2(T) Q3(Released) = x3Q 02(Excess) = f(a3;b;x3) Footnotes: T = Process Temperature t Time Q caloric value of the fuel Q He;3t tensity of combustion and the flame is non-luminous. It is therefore best used as a cutting torch which transfers most of its heat by impingement on a very small area. The PYRETRON-EAF combustion system by contrast delivers one type of flame structure for heating of scrap in the furnace and then adjusts to another structure for melting once the scrap is hot. In this fashion, it can provide heat to the scrap much cheaper than with electricity for most locations. Operating results confirm that the replacement of oxy-fuel burners by PYRETRON systems in EAF furnaces ranging from 35 to 160 tons did significantly improve melting performance. By using 177 on average less than 50% of the purchased oxygen required by oxy-fuel burners the PYRETRON reduced the cost of Btu's being introduced by natural gas by more than 30%. From a metallurgical standpoint, a PYRETRON system in a small 5 ton furnace producing steel with 2% carbon and 20% chromium proved that by continuously adjusting the flame characteristics, the PYRETRON system was able to melt metal that is very sensitive to oxidation without any deterioration of chemistry. It has also been proven that substitution of the PYRETRON system for oxy-fuel burners can more than double the energy introduction and can increase the savings of electrical |
