Saturated steam at 100 degree C is used to heat a 150 kg/hr biomass (C_p = 3.26

Question

Saturated steam at 100 degree C is used to heat a 150 kg/hr biomass (C_p = 3.26 J/g middot K) present in a reactor from 20 degree C to 50degree C. Steam does not mix and completely segregated from the material in the steam chest. Steam is completely condensed and leaves the reactor as saturated water at 100 degree C from the steam chest. The rate of heat loss from the steam chest to the surroundings is 1.5 k/s. i) Determine the heat that needs to be added to the biomass. ii Using steam table, determine the change in specific enthalpy of steam to water. iii) Write the simplified energy balance for this case. iv) How many kilograms of steam are needed per hour?

Explanation / Answer

Heat to be supplied to the biomass= mass*specific heat* temperature difference= 150kg/hr*3.26KJ/kg.K*(50-20)=14670 Kj/hr= 4.1 Kj/sec

Heat loss from the steam chest to surroundings = 1.5Kj/s

Writing energy balance equation

Total heat to be supplied = heat supplied to bio mass+ heat loss from steam chest to surroundins= 4.1+1.5= 5.6 kj/sec

Enthalpy of steam at 100 deg.c= 2675.43 Kj/kg and that of liquid = 417.51 Kj/kg This data is obtained from steam tables

Hence enthalpy change 2675.43-417.51 =2257.92 Kj/kg

Steam required = 5.6 KJ/sec/ 2257.92 Kj/kg =0.00248 Kg/sec= 0.00248*3600 kg/hr=8.93 Kg/hr

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.