Question about Multiple Stream Mixings into Units

Click For Summary
SUMMARY

This discussion focuses on performing thermodynamic analysis for a system with multiple streams entering and exiting a condenser and a feed-water heater. The user has defined one stream completely and assumes equal pressure for all streams entering and exiting the condenser. The challenge lies in balancing the multi-stream units, particularly in understanding the behavior of mixing points and heat exchangers. Key concepts include the adiabatic nature of mixing points and the principle that heat exchangers do not perform work, with enthalpy equating to heat transfer (Q).

PREREQUISITES
  • Understanding of thermodynamic principles, specifically unit operations.
  • Familiarity with heat exchangers and their operational characteristics.
  • Knowledge of enthalpy and its role in energy balances.
  • Basic skills in performing mass and energy balances in thermodynamic systems.
NEXT STEPS
  • Study the principles of multi-stream unit operations in thermodynamics.
  • Learn about the energy balance equations for heat exchangers.
  • Research the concept of adiabatic mixing and its implications in thermodynamic systems.
  • Explore case studies involving condensers and feed-water heaters in thermodynamic cycles.
USEFUL FOR

Students in thermodynamics courses, engineers working with thermal systems, and professionals involved in energy management and process optimization will benefit from this discussion.

royblaze
Messages
74
Reaction score
0

Homework Statement



I'm currently doing some thermodynamic analysis. I don't know where to put this question, but here goes:

I have a system that has two streams entering a condenser, and one leaving. I don't know mostly anything about two of the streams.

One stream I have fully defined via other unit balances. I am making an assumption: all streams entering the condenser must be the same pressure, and as a result, so too must the exit stream. The exit stream is a saturated liquid, from the question.

I am making this same assumption on a feed-water heater, which has two streams in, and two streams out. One of the streams leaves as a saturated liquid to a throttler, whose exit stream goes back to the condenser.

The feed-water heater's other outlet stream goes to a boiler, and then to a two turbine system, where between the two turbines, one stream goes to the feed-water heater. The second turbine's outlet goes to the condenser.

I'm having a real tough time trying to balance the multi-stream units. This is an intro to thermodynamics class with one of the worst lecturers in history. We have learned how to balance units when one stream enters and then exits. We have not learned anything about units that have multiple streams entering.

So far, we have learned that mixing points are adiabatic with equal pressure inlets. We also know that heat exchangers (which I assume the condenser and feed-water heater are) do no work, and the enthalpy is equal to Q.

Could I just get a few tips/facts about how to go about this unit balance?

Here's a picture. See attached:
 

Attachments

  • 213.jpg
    213.jpg
    45 KB · Views: 462
Physics news on Phys.org
I have solved the question after clarifying some assumptions that were not given to us.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K