Answer to Question #160418 in Physical Chemistry for deepak

Question

Some calculations related to oxygen enrichment of blast are given in the Table below. Given: heat capacity of solid (kcal/THMoC) for upper and lower part of BF are 500 and 1700, respectively. Average volumetric heat capacities (kcal/Nm3 - oC) of air and blast furnace gas are 0.333, and 0.337, respectively. Blast preheat at 1000oC and burden inlet at 30oC. Assume, tuyer gas is 100% CO, and heat of reaction for CO formation is 111000kJ/kg-mole. Carbon rate 400 kg/THM. Fill in the blanks of the table below. % O2 in air Tuyer gas volume Nm3 /kg.C Tuyer gas heat content kcal/kgC RAFT ( oC) heat capacity of gas kcal/THMoC Top gas temperature ( oC) Blast Volume Nm3 /kg.C 21 4.44 5.38 3682 2032 725 300 27 (14)________ 4.39 (15)_________ 2267 592 (16)________ 29 3.22 4.15 3274 2340 (17) _______ 123 36 2.59 (18)_______ 3066 (19)________ 485 (20)________

a.Blast Volume (Nm3 /kg.C) at 27% oxygen in air is ______________.

b.Tuyer gas heat content in kcal/kg.C at 27% oxygen in air is _____________

c.Top gas temperature ( oC) for 25% oxygen in air is ______________.

d.Heat capacity of gas in kcal/THMoC at 29% oxygen in air is ______________.

e.Tuyer gas volume in Nm3 /kg.C at 36% oxygen in air is______________.

f.RAFT in oC at 36% oxygen in air is ______________.

g.Top gas temperature ( oC) for 36% oxygen enrichment in air is ______________

Answer 1

We now introduce two concepts useful in describing heat flow and temperature change. The heat capacity (C

C) of a body of matter is the quantity of heat (q

q) it absorbs or releases when it experiences a temperature change (ΔT

ΔT) of 1 degree Celsius (or equivalently, 1 kelvin)

C=q

ΔT

(12.3.1)

(12.3.1)C=qΔT

Heat capacity is determined by both the type and amount of substance that absorbs or releases heat. It is therefore an extensive property—its value is proportional to the amount of the substance.

For example, consider the heat capacities of two cast iron frying pans. The heat capacity of the large pan is five times greater than that of the small pan because, although both are made of the same material, the mass of the large pan is five times greater than the mass of the small pan. More mass means more atoms are present in the larger pan, so it takes more energy to make all of those atoms vibrate faster.