Chemical Engineering Answers

It is required to heat 10000 bbl/ day of crude oil (as given in case study of Lecture3) in a fired still heater from 220 "F to 622 "F and vaporize (gasoline, naphtha, kerosene, light gasoil, heavy gasoil) of the crude oil using refining gas, (NHV=50000 Btu /lb). In the radiant section contains 1500 ft of projected area, and the tubes (5 in. outside diameter) are spaced at a center-to-center distance of 10 in. there is only one row of radiant tubes, and they are 40 ft long. The ratio of air to fuel is 17.

Given: Average Specific heat of the crude oil = 2.3 Btu/ lb "F, average latent heat of vaporization is 120, 113, 100, 95, 90 Btu/lb for (gasoline, naphtha, kerosene, light gasoil, heavy gasoil)

respectively, and the furnace efficiency is 75% calculate:

a) The mass flow rate of the fuel required? b) How many Btu are absorbed per hour in radiant section?

c) How many Btu are absorbed per hour through each square foot of projected area?

Given:

1 bbl =42 gal.

P water =8.33 Lb/gal

A pipeline connecting two tanks contains four standard elbows, a plug valve that is fully open and a gate valve that is half open. The line is commercial steel pipe, 25 mm internal diameter, length 120 m. The properties of the fluid are: viscosity 0.99 mNM_2 s, density 998 kg/m3. Calculate the total pressure drop due to friction when the flow rate is 3500 kg/h

nswer to Question #158361 in Chemical Engineering for Adeleke olumide

Answers>Engineering>Chemical Engineering

Question #158361

A distillation is designed to separate ethanol and water continously.The feed contains 40% mole of methanol and 60%mole of water and its saturated liquid.The pressure is 101.3kpa.For which the binary equilibrium data are

X =2.0 6.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 95.0

Y =13.4 30.4 41.8 57.9 66.5 72.9 77.9 82.5 87.0 91.5 95.3 97.9

The feed is to be introduced at optimal location for minimum stage, 95% for methanol is to be recovered in a liquid distillate containing 98% methanol.The reflux is to be a saturated liquid with a flow rate of 1.25times the minimum reflux rate which is corresponding infinite stages. Assuming constant molar overflow.Find

a. the no of equilibrium stages required in the column

b.no of plates required for the Distillation column given that the overall column efficiency is 75%.

c. locate the plate where the feed has to be introduced into the column.

A distillation is designed to separate ethanol and water continously.The feed contains 40% mole of methanol and 60%mole of water and its saturated liquid.The pressure is 101.3kpa.The feed is to be introduced at optimal location for minimum stage, 95% for methanol is to be recovered in a liquid distillate containing 98% methanol.The reflux is to be a saturated liquid with a flow rate of 1.25times the minimum reflux rate which is corresponding infinite stages. Assuming constant molar overflow.Find the no of equilibrium stages required in the column, find the no of plates required for the Distillation column given that the overall column efficiency is 75%, locate the plate where the feed has to be introduced into the column.

a)  Write down the equation for the relationship between the shear stress and the shear rate for Newtonian fluid defining the variables and parameters used.

b) Oil with a density of 770 kg m⁻³ flows through a pipe with a diameter of 30 cm at a rate of 20,000 tonnes per day. Calculate the velocity of the oil in the pipe.

c)  A liquid flows in a hosepipe of internal diameter 1.8 cm with a velocity of 150 cm s^-1. Calculate the velocity of the water in the nozzle at the end of the pipe which has a diameter of 0.75 cm.

d) Water at 20°C and 1 atm has a density = 998.0 kg/m3. Calculate the density at 35°C to 3 significant figures if the coefficient of volume

∆𝜌𝜌⁄𝜌𝜌

expansion of the water is given by 𝛽𝛽 = − = 0.337x10^-3 K^-1.

∆𝑇𝑇

e) A brick wall with 0.1 m thickness (k = 0.7 W m⁻¹K⁻¹) is exposed to a cold wind at 270 K through a convection heat transfer coefficient of

                          40 W m⁻²K⁻¹. On the other side is calm air at 330K, with a convection

heat transfer coefficient of 10 W m⁻²K⁻¹. Calculate the rate of heat transfer per unit area (heat flux).

A continuous stirred tank reactor is performing a slightly exothermic reaction at 300 K, with products that are highly corrosive and abrasive.

(i) Discuss and justify the best type of heat exchanger to use.

(ii) Although the reaction is exothermic, the heat exchanger must provide heat to keep the reactor at constant temperature. Explain and justify how this is possible.

Case Study # 1 - A major company was unsuccessful in bidding on a complex gyroscopic control system for a military aircraft. Using strong political connections with the White House, they forced a Pentagon level review of the evaluation. The proposal claimed all portions of the system were produced in company facilities. On a visit to one of the qualified suppliers of Rate Switching Gyros, Air Force personnel had witnessed production of units with name plates of the major supplier. The qualified supplier was a very small company.

Questions:

Is it ethical for a company to subcontract equipment and then claim in a proposal that it is produced in house? 

Where is the line drawn between a typical purchased subassembly which goes into a larger product?

Air with a humidity, YM, of 0.012 kg H2O / kg dry air enters a recirculating drier, where it removes some water from a solid material (S) and leaves with a humidity, YP, of 0.030 kg H2O/kg dry air. A fraction of the wet air leaving the drier is removed from the process and the rest is recycled. Fresh make-up air with a humidity, YF, of 0.004 kg H2O/kg dry air is mixed with the recycled air. The water (W) removed from the solid material S leaves in the system in stream P? Calculate (a) The mass of water removed per kg of feed air supplied (4 marks) (b) The percentage of wet air removed after the drier. (4 marks)

a)  Write down the equation for the relationship between the shear stress and the shear rate for Newtonian fluid defining the variables and parameters used.

b) Oil with a density of 770 kg m⁻³ flows through a pipe with a diameter of 30 cm at a rate of 20,000 tonnes per day. Calculate the velocity of the oil in the pipe.

c)  A liquid flows in a hosepipe of internal diameter 1.8 cm with a velocity of 150 cm s^-1. Calculate the velocity of the water in the nozzle at the end of the pipe which has a diameter of 0.75 cm.

d) Water  at 20°C and 1 atm has a density = 998.0 kg/m3. Calculate the density at 35°C to 3 significant figures if the coefficient of volume

∆𝜌𝜌⁄𝜌𝜌

expansion of the water is given by 𝛽𝛽 = − = 0.337x10^-3 K^-1.

∆𝑇𝑇

e) A brick wall with 0.1 m thickness (k = 0.7 W m⁻¹K⁻¹) is exposed to a cold wind at 270 K through a convection heat transfer coefficient of

                          40 W m⁻²K⁻¹. On the other side is calm air at 330K, with a convection

heat transfer coefficient of 10 W m⁻²K⁻¹. Calculate the rate of heat transfer per unit area (heat flux).