PBL_Heat+Exchangers

__**Introduction** **to Heat Exchangers**__

A large number of production facilities in many industries use processes in which heat energy is transferred between different fluids. The basic principle of heat transfer is extremely simple, two fluids at different temperatures are placed in contact with a conductive barrier (the tube wall) and heat is transferred from the hotter fluid to the colder fluid until they reach the same temperature level.

//Outer look of a heat exchanger used in petrochemical industry//

//Inner look of a "shell and tube" heat exchanger//

They are widely used in [|space heating], [|refrigeration], [|air conditioning], [|power plants], [|chemical plants], [|petrochemical plants], [|petroleum refineries], and [|natural gas processing]. One common example of a heat exchanger is the [|radiator] in a car, in which the heat source, being a hot engine-cooling fluid, [|water], transfers heat to air flowing through the radiator [i.e. the heat transfer medium].

"Countercurrent" heat exchangers occur naturally in the circulation system of [|fish] and [|whales]. Arteries to the skin carrying warm blood are intertwined with veins from the skin carrying cold blood, causing the warm arterial blood to exchange heat with the cold venous blood. This reduces the overall heat loss in cold waters. Heat exchangers are also present in the tongue of [|baleen whales] as large volumes of water flow through their mouths.Wading birds use a similar system to limit heat losses from their body through their legs into the water.

__**Independent Preparatory Work** **(Wk 2)**__ Read up on the following topics:

**1) How does a heat exchanger works? 2) Types of heat exchangers.**

You are a team of mechanical engineers in Halliburton, a US-based oil and gas company. A new floating oil-rig is being built and your team has been tasked to manage the purchase of the heat exchanger needed to heat up crude oil. 30 000 lb/h of crude oil are to be heated from 70 to 136 F by heat exchange with the bottom product from a distillation column. The product is to be cooled from 295 to 225 F.  viscosity = 2.9 mPa.s thermal conductivity = 0.0789 BTU/ft.h.F density = 51.5 lb/ft3 ) //**
 * __Problem-based Learning__**
 * __Properties of Crude Oil__**
 * // heat capacity = 0.475 BTU/lbF

viscosity = 5.2 mPa.s thermal conductivity = 0.069 BTU/ft.h.F density = 54.1 lb/ft3 //**
 * __Properties of Product__**
 * // heat capacity = 0.525 BTU/lbF

The Chief engineer calls up your team and informed that a used heat exchanger (specification sheet below) is being displaced from another project.

He tasked your team to:

1) Check if the displaced heat exchanger can be used in your project 2) If not, design a heat exchanger suitable for this project.

__**Group Sharing Presentation Schedule**__ - conductivity of fluid || 3 || - flow velocity || 4 || - turbulent flow - Reynold’s number || 5 || - transfer area || 7 ||
 * Week || Topic || Group Presenting ||
 * 5 || - types of heat exchange || 1 ||
 * ^  || - operation of a shell and tube heat exchanger || 2 ||
 * 5 || - density of fluid
 * ^  || - viscosity of fluid
 * 6 || - laminar flow
 * ^  || - pressure drop during fluid flow || 6 ||
 * 7 || - tube length
 * ^  || - specific heat capacity || 8 ||
 * 7 || - heat transfer rate || 9 ||
 * ^  || - overall heat transfer coefficient || 10 ||
 * ^  || - effectiveness of a heat exchanger || 11 ||