Viewlet Title
Getting Started with Coil Wound Heat Exchange in Aspen Exchanger Design and Rating 2: Configuring Stream Occupancy
Â
Description
Learn how to translate your coil wound stream configuration into inputs for Aspen Coil Wound via this detailed demonstration, featuring an animated breakdown of how to define the stream occupancy for a typical top cold, 2 bundles, shell side evaporation coil wound exchanger.
About the Series
Coil Wound heat exchanger, also known as Spiral Wound or Wound Coil exchanger, is a principal heat transfer equipment in LNG process. Using Aspen Coil Wound, available in Aspen EDR from V9.1 and beyond, you can rigorously rate and/or simulate Coil Wound Exchanger.
In this Getting Started series, you will learn how to simulate a multi-stream heat exchanger using Aspen Coil Wound. Using the provided inlet conditions, stream compositions, and exchanger geometry data in Coil Wound Getting Started Guide provided in the product documentation, you will build a simulation case to determine the outlet conditions of the streams.
1. Creating a Coil Wound Simulation
2. Configuring Stream Occupancy
3. Defining Stream Process and Property Data
4. Specifying Coil Wound Bundle Geometry
5. Viewing Coil Wound Results
By the end of the series, you will be able to understand the model requirements, and simulate a principle heat transfer equipment in LNG process using Aspen Coil Wound.
APCI C3/MCR process
In this video, you will define your stream configuration to best match the coil wound exchanger you are trying to model.
Previously, we created a new Coil Wound model.
On the Problem Definition | Application Options form. Enter the number of streams and bundles for a typical top cold, 2 bundles coil wound exchanger.
This leads us to the Occupancy form. Now it’s time to configure the coil wound stream occupancy for a typical top cold, 2 bundles, shell side evaporation coil wound exchanger.
First, regardless of the LNG process, all exchangers are installed vertically. The natural gas, stream 3, enters the tubes and travels upward through both bundles
Entering the tube sides along with the product stream are: stream 2, the MRV or mixed refrigerant vapor, and stream 5, MRL or mixed refrigerant liquid. They, too, flow upward.
Stream 2 now goes all the way to the top, exits the tubes, passes through a Joule Thompson valve, becomes stream 1 and is returned to the top bundle - but now as a low pressure mix refrigerant, flowing downward on the shell side.
Similarly, stream 5 exits and loops back to the shell side of the bottom bundle. There it mixes with stream 1 flowing downward from the top bundle.
The mixing of stream 1 and stream 5 is represented by a new stream, stream 4, which eventually exits the exchanger at the bottom.
A couple of things to note here. Coil wound heat exchangers for LNG applications have downward evaporation and upward condensation.
This means you can keep relatively slower velocity, which can minimize pressure loss and avoid evaporation temperature rise.
And the high mass fluxes on the tube side keep the condensate flowing up the tubes.
This is why majority of the mixed refrigerant process using Coil Wound Exchangers adopts the top cold configuration. Contrary to that in the Plate Fin.
Can you think of other configurations of Coil Wound that you may have encountered in practice? How would they translate to inputs for the simulator?
Once you have successfully configured the stream occupancy to best match the exchanger you are trying to model, it’s time to enter Process Data and Physical Property Data
Playing the Viewlet
A Viewlet is an animation sequence constructed by capturing a series of screen shots from a software application. Viewlets are used to demonstrate product features and to train users in simple procedures.
Viewlet screencasts are played using Camtasia Studio. Click on the attachment above to launch the program.