An annealing furnace in an iron-steel enterprise with an energy cost of 0.035 /kWh is operated...

Transcribed Image Text:

An annealing furnace in an iron-steel enterprise with an energy cost of 0.035 €/kWh is operated 8700 hours per year. The inlet temperature of the combustion air is 10°C. The operation costs 0.025 €/kWh to cool the flue gas from the annealing furnace at 800°C to 120°C. In order to Thi h,1 h,1 increase the temperature of the combustion air and to reduce the cooling costs, the management plans to purchase one crossflow heat exchanger with an overall heat transfer coefficient of 0.018 kW/m2K and an area unit cost of 250 €/m2. The heat capacities of the flue gas and Th2 3 2 combustion air are determined as 6 kW/K and 8 kW/K respectively, and the depreciation Th2 coefficient is determined as 0.15 1/a. The management has allocated a 20000 €/a budget and aims to save at least 300 000 €/y; a. Draw the process diagram. (5 P) b. Calculate the heat exchanger effectiveness values. (5 P) Calculate the cold flow outlet temperature. (5 P) d. Determine the amount of transferred heat. (5 P) Determine the required heat exchanger surface area. (10 P) f. Determine the total investment cost of the heat exchanger. (5 P) g. Calculate the annual investment cost. (5 P) h. Calculate the annual financial benefit. (5 P) Calculate the amount of savings. (5 P) j. Will the enterprise realize this investment? Why? (5 P) k. If the enterprise preferred a counter flow heat exchanger, what could you tell about the cold flow output temperature and the required heat transfer surface area. (5 P) Create the necessary matrices and vectors such as Effectiveness, Structure, Input, Output and Temperature matrices for cell effectiveness are ɛh=0.69, ɛc=0.36. (10) m. Solve the static simulation using the matrices and vectors (30 P) с. е. i. 1. (1-e-CNTUY Ecross = 1 - (xn + xe)TBU(Tni - Tea) NTUcross = - -In[C. In(1 - e) + 1] S = TBQR(Xn + xe) - NKAZ 4- An annealing furnace in an iron-steel enterprise with an energy cost of 0.035 €/kWh is operated 8700 hours per year. The inlet temperature of the combustion air is 10°C. The operation costs 0.025 €/kWh to cool the flue gas from the annealing furnace at 800°C to 120°C. In order to Thi h,1 h,1 increase the temperature of the combustion air and to reduce the cooling costs, the management plans to purchase one crossflow heat exchanger with an overall heat transfer coefficient of 0.018 kW/m2K and an area unit cost of 250 €/m2. The heat capacities of the flue gas and Th2 3 2 combustion air are determined as 6 kW/K and 8 kW/K respectively, and the depreciation Th2 coefficient is determined as 0.15 1/a. The management has allocated a 20000 €/a budget and aims to save at least 300 000 €/y; a. Draw the process diagram. (5 P) b. Calculate the heat exchanger effectiveness values. (5 P) Calculate the cold flow outlet temperature. (5 P) d. Determine the amount of transferred heat. (5 P) Determine the required heat exchanger surface area. (10 P) f. Determine the total investment cost of the heat exchanger. (5 P) g. Calculate the annual investment cost. (5 P) h. Calculate the annual financial benefit. (5 P) Calculate the amount of savings. (5 P) j. Will the enterprise realize this investment? Why? (5 P) k. If the enterprise preferred a counter flow heat exchanger, what could you tell about the cold flow output temperature and the required heat transfer surface area. (5 P) Create the necessary matrices and vectors such as Effectiveness, Structure, Input, Output and Temperature matrices for cell effectiveness are ɛh=0.69, ɛc=0.36. (10) m. Solve the static simulation using the matrices and vectors (30 P) с. е. i. 1. (1-e-CNTUY Ecross = 1 - (xn + xe)TBU(Tni - Tea) NTUcross = - -In[C. In(1 - e) + 1] S = TBQR(Xn + xe) - NKAZ 4-

Answer rating: 100% (QA)

Soln Inlet temp of combustion air Tci 1o C Flue gas inlet outlet temp Thi 800 C Tho 120 C Cooling co... View the full answer