During batch and continuous operations in the real world the

During batch and continuous operations in the real world, the added nitrogen source is in 20% excess of stoichiometric needs. Redo the calculation for (b), assuming that a 20% excess of nitrogen is supplied in the feed stream. The body needs a constant supply of energy in order to survive. The minimum level of energy required just to perform chemical reactions in the body and other organs is known as the basal metabolic rate (BMR) However, if an individual is to engage in such activities as eating and walking, additional energy must be available. On average, an individual performing normal daily activities expends 2750 kcal/day. The daily energy expenditure is comprised of maintaining the BMR, digesting and processing food (220 kcal), and purposeful physical activity (690 kcal) Given that breathing accounts for 5% of the BMR, calculate the energy required for an individual at rest to breathe. Report your answers in units of joules/breath. Heavy exercise can increase the daily energy expenditure to 7000 kcal. In addition, exercise can increase the energy requirements for breathing about 20-fold. Calculate the energy expended for purposeful physical activity when exercising. Report your answer in units of joules/breath.

Solution

a. normal daily activities = 2750 kcal/day

digesting and processing food = 220 kcal

maintaining body temperature = 190 kcal

purposeful physical activity = 690 kcal

BMR (basal metabolic rate) = 2750 - (220 + 190 + 690)

= 1650 kcal

breathing accounts for 5% of the BMR = 82.5 kcal/day

1 kcal = 4184 joules

Energy spent for breathing in a day = 345180 joules

1 day = 1440 min

1 min = 12 breaths

Total breaths in a day = 17280 (12 x 1440)

17280 breaths = 345180 joules

So, Single breathe need 19.97 Joules.