Question

TiCl4 is formed by reacting titanium dioxide (TiO2) with hydrochloric acid (see reaction below).
TiO2 is available as an ore containing 88 % TiO2 and 12 % inerts. The HCl is available as 50 wt% solution (the balance is water). The per pass conversion of TiO2 is 55 % (this means that 55% of the titanium dioxide entering the reactor is converted to products). The HCl is fed into the reactor in 20 % excess. Pure un-reacted TiO2 is recycled back to mix with the TiO2 feed.
TiO2 + 4 HCl  TiCl4 + 2H2O
For 1 kg of TiCl4 produced, determine:
a) The kg of TiO2 ore fed.
b) The kg of 50 wt % HCl solution fed.
c) The ratio of recycle stream to fresh TiO2 ore.
Note: MW : TiO2 79.9; HCl 36.47; TiCl4 189.7

Answer 1

Basis :- 1.0 Kg of TiCl4 Produced.

For a) According to reaction - 1Tio2+ 4Hcl - -> 1TiCl4 + 2H2O

1 Kg if Tio2 & 4 Kg of Hcl gives 1 kg of tiCl4 & 2 Kgs of H2o

1 kg TiO2 ore contains 0.88 kg Tio2 lg & 0.12 kg of inerts, But 55 % of TiO2 conversion (by cross multiplicatition) = 55x0.88/ 100 =0.484 kg of Tio2 is converted of 1 kg Ore but reaction requires 1 kg of TiO2 so Ore requres for 1 kg (By Cross multiplication) = 1.0 x 1.0/0.484 =2.066 kgs of TiO2 ore fed

b) according to reaction 4 kg of Hcl are required for the required

so in 1 kg of 50% Hcl soution contains 0.50 kg of Hcl & 0.50 kg of water

so for 4 kg of Hcl we have to feed into reactor (by cross multiply=0.5 kg Hcl requires i kg 50 %Hcl

4.0 kg Hcl requires ? = 1.0 x 4.0 /0.5 = = 8.0 kg of 50 % Hcl solution

but 20 % extra 50 % Hcl solution is fed to reactor so by cross multiply for 100 kg soln 120 kg solution is fed

for 8.0 kg soln How Much ?

= 120 x 8.0 / 100 = 9.6 kg of 50 % Hcl solution is fed

C ) fresh Tio2 ore converted is 55 % that means according to the reaction 1 kg of Pure TiO2 is require for the conversion into product , in one kg of ore 0.88 kg of TiO2 is contained but only 55 % is cinverted into product by cross multiplication =100 kg TiO2 55 kg conversion so for

0.88 kg TiO2 How Much = 0.88 x 55 / 100 = 0.484 kg converted

for 1 kg TiO2 How Much Ore is required ? = 0.484 kg TiO2 1 kg ore

1 kg TiO2 how Much ? = (by cross multiplication ) 1.0 x 1.0 / 0.484 = 2.066 kg of ore is required

So recycled Stream = 2.066 ( fresh Ore feed ) - 1.0 ( converted TiO2 ) =1.066 kg ore

Ratio = recycle sream / freash sream = 1.066 /2.066 = 0.515