Process Analysis

Need this fast. Only solve if sure of the answer. I'll downvote and complain to chegg customer service if wrong or copied. Thanks!

Problem 2: [40 MARKS] You are a process engineer working on setting up a medicinal plant company. One of the key steps is to dry wet solids in a continuous manner. As part of the design process, your company has approached two vendors to propose a dryer design. You have given them both the following specifications: Ambient air is at 20 C and 20% RH The maximum temperature of the air entering the unit should be less than 50 C As the solid travels through the dryer, water is evaporated at the rate of 100 kg/s. The dryer should be adiabatic Two vendors have proposed their designs. Each claim that its design is superior in terms of energy consumption. Upon inspection, you have narrowed down the key differentiators and prepared a simplified block flow diagram as shown in the attached sheet. Design 1 is a once-through dryer. Ambient air is heated up to 50 C and sent to the dryer. The moist air that has picked up the water from the solids leaves the dryer with an RH of 90%. Design2 is a dryer with partial recirculation. In this design, a portion of the outlet air is recirculated; mixed with the ambient air; heated to 50 C and introduced into the dryer. In the proposed design, the ratio of dry airflow in stream 4 to the dry airflow in stream 3 is 0.5. In other words, 50% of stream 3 is recirculated. The outlet air (stream 3) emerges at 90% RH Your role is to perform the following: 1. For Design 1, show the path taken by air as it travels through the dryer. Indicate the states and paths on the psychrometric chart titled Design 1. (5 MARKS] 2. By showing appropriate balances, complete the stream table. [5 MARKS] 3. What is the heat duty (in kW) of the heater in Design 1? [5 MARKS] 4. Design 2 is not straightforward to analyze, but there is enough information to solve it. Explain how you will approach this design and estimate all the associated states (1 to 4). If needed, describe your solution using the psychrometric chart titled Design 2 (10 MARKS] 5. By showing appropriate balances, complete the stream table. [5 MARKS] 6. What is the heat duty (in kW) of the heater in Design 2? [5 MARKS] 7. Which design will you recommend and why? [5 MARKS] Recirculated Air Heater Ambient air Air out 90% RH Ambient air Heater Air out 90% RH 3 Design: Once-through Adiabatic Dryer Design 2: Adiabatic Dryer with partial air recirculation Dried Solid Wet solid Dried Solid Wet solid Once through Adiabatic Dryer Adiabatic Drier with air recirculation 1 2 3 1 2 3 4 Dry air flow [kg/s] Temperature (C] 20 50 20 50 Relative humidity [%] 20 90 20 90 90 Moisture content [kg W/kg DA] Enthalpy (kJ/kg) PSYCHROMETRIC CHART FOR DESIGN 1 120 125 130 135 140 50 40 45 100 105 110 115 SE 00 85 5076 Enthalpy At Saturation, kl/kg Dry Air 80 65 70 75 80 45 50 XOV 145 55 F0.033 0.032 0.031 0.030 F0.029 0.028 20.027 0.026 0.025 0.024 F0.023 0.022 0.021 0.020 20.019 0.018 0.017 0.95 0.016 0.015 0.014 0.013 0.012 0.011 0.010 0.009 0.008 0.007 -0.006 F0.005 0.004 0.003 0.002 0.001 F0.00 55 55 30% 35 is 23 30 20% 20 25 10 15 Moisture Content, kg/kg Dry Air 5 10 10% Wet Bulb or Saturation Temperature, C 40 A -10 0 10 15 20 25 30 40 45 50 -10 35 0.80 Dry Bulb Temperature, C 0.85 Below 0C Properties and Enthalpy Deviation Lines Are For Ice Humid Volume, m/kg Dry Air 0.75 0.90 ATTACH THIS PAGE WITH YOUR SOLUTIONS PSYCHROMETRIC CHART FOR DESIGN 2 120 125 145 130 40 135 45 140 50 35 550.033 95 100 105 110 115 0 25 SUS Enthalpy At Saturation, kl/kg Dry Air 45 50 55 60 65 70 75 80 85 40% 0.032 +0.031 0.030 E 0.029 0.028 E 0.027 0.026 20.025 0.024 F0.023 0.022 F0.021 0.020 0.019 F0.018 E0.017 0.95 0.016 0.015 0.014 F0.013 0.012 0.011 0.010 0.009 0.008 F0.007 0.006 0.005 +0.004 0.003 0.002 +0.001 F0.00 55 79 00 30% 35 15 30 C 40 20% 20 - 10 10 15 Moisture Content, kg/kg Dry Air 5 01 10% 0 Wet Bulb or Saturation Temperature, 02 2 -10 10 15 20 25 30 35 40 45 50 0.80 0.90 0.75 Dry Bulb Temperature, 0.85 Below 0C Properties and Enthalpy Deviation Lines Are For Ice Humid Volume, m/kg Dry Air ATTACH THIS PAGE WITH YOUR SOLUTIONS