The supplier told you that the data sheet used for the analysis of the coal got lost during the transport but he remembers that it contains 70.1% carbon, 6.9% moisture and 8% ash. He is also sure that...

The supplier told you that the data sheet used for the analysis of the coal got lost during the transport but he remembers that it contains 70.1% carbon, 6.9% moisture and 8% ash. He is also sure that the N and S content of the coal is negligible. You then instruct your subordinates to introduce the coal in the boiler together with air. The air you use for combustion is assumed to be dry at 75°F. Upon taking a sample of the stack gas, you measured its conditions to be at 850°F and 745 mmHg. The equipment you make use of for the stack gas analysis gave you 11.2%CO2, 0.7%CO and 8.3% O2.

a. Express in percentage how much excess air is needed for the boiler. The valve used to regulate the amount of air needed makes use of volume/lb of coal. What value should be maintained?

b. Your daily report requires you to submit the volume of stack gas produced. Your subordinates used 50 tonnes of coal that day.
Establish basis as 100 lbmols of stack gas. Provide the process flow diagram.