Steam Tables: Oil fired boiler questions

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Discussion Overview

The discussion revolves around a homework problem related to steam tables and oil-fired boilers, specifically focusing on calculations involving the properties of steam at different pressures. Participants seek assistance in understanding and solving the problem presented in a practice mechanical science exam.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant expresses confusion regarding the calculations for parts a) and b) of the exam question and requests suggestions or solutions.
  • Another participant advises double-checking calculations and notes that the boiler operates at a pressure of 1050 kPa, which they interpret from an attached image.
  • Concerns are raised about the use of properties of saturated steam at 1.5 bar in the participant's solution for part a) and the enthalpy of superheated steam at the same pressure for part b).
  • A participant corrects their earlier misunderstanding, stating that 1050 kPa is equivalent to 10.5 bar, not 1.5 bar, and acknowledges the need to input correct figures for enthalpy.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct approach to the problem, as confusion remains regarding the pressure values and their implications for the calculations. Multiple viewpoints on the correct interpretation of the problem persist.

Contextual Notes

There are limitations in the clarity of the attached image, which may affect the understanding of the problem statement. Additionally, there are unresolved mathematical steps related to the calculations for the properties of steam.

BenC1994
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Homework Statement


This is from a practice mechanical science exam for HNC engineering.

See attachment for the question sheet off a practice exam. I have no idea how to do this after the a and b parts and my answers for which are below the question (underlined), any suggestions or solutions would be greatly appreciated.

Homework Equations


Q = M*c*(Temperature Difference)
I think...

The Attempt at a Solution

 

Attachments

  • 1431102341742-301758455.jpg
    1431102341742-301758455.jpg
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BenC1994 said:

Homework Statement


This is from a practice mechanical science exam for HNC engineering.

See attachment for the question sheet off a practice exam. I have no idea how to do this after the a and b parts and my answers for which are below the question (underlined), any suggestions or solutions would be greatly appreciated.

Homework Equations


Q = M*c*(Temperature Difference)
I think...

The Attempt at a Solution


You should double check your calculations for parts a) and b).

According to the problem statement, the boiler operates at a pressure of 1050 kPa. {At least, that's what I can read from the tiny image attached.}

Your solution for part a) says that the properties of saturated steam are for at pressure of 1.5 bar.

Your solution for part b) appears to be using the enthalpy of superheated steam at a pressure of 1.5 bar.

What's the definition of a bar?
 
SteamKing said:
You should double check your calculations for parts a) and b).

According to the problem statement, the boiler operates at a pressure of 1050 kPa. {At least, that's what I can read from the tiny image attached.}

Your solution for part a) says that the properties of saturated steam are for at pressure of 1.5 bar.

Your solution for part b) appears to be using the enthalpy of superheated steam at a pressure of 1.5 bar.

What's the definition of a bar?
Ah I see my mistake with the answer now, 1050kpa would be 10.5 bar not 1.5 Bar

1.5 bar is 1.5x10^5 pa or n/m^2

Will correct mistake, input correct figures for h and include a better image...
 

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