Help with a problem to design a vessel

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    Design Vessel
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Discussion Overview

The discussion focuses on the design of a heating system for three jacketed reactors, specifically addressing the sizing of a heater and the appropriate pipe sizes for the water supply and return lines. Participants explore the application of heat transfer equations and fluid dynamics principles relevant to the system's operation.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related
  • Debate/contested

Main Points Raised

  • One participant suggests treating the jacketed vessels as heat exchangers and using the heat transfer equation to determine the heater size, proposing to multiply the heat transfer rate by three for the three reactors.
  • Another participant indicates that the problem statement provides enough information to calculate the power required for each reactor based on flow rate and temperature drop, but expresses uncertainty about pipe sizing.
  • A later reply mentions needing the flow rate to determine pipe diameters and suggests that the maximum allowable flow rate through the jacket is 50 USGPM.
  • One participant proposes that to determine pump head and flow rate, one could select a pump, plot the system and pump curves, and find the operating point at their intersection.
  • Another participant, unfamiliar with the topic, suggests making a drawing to mark flow rates and calculate pressure losses, including those in the heater, to determine the required pump power.

Areas of Agreement / Disagreement

Participants express various approaches to the problem, with no consensus on the best method for calculating heater size or pipe diameters. Some participants agree on the need for flow rate information, while others propose different methods for determining pump head and sizing.

Contextual Notes

Participants note limitations in the information provided, such as the need for specific flow rates and pressure loss calculations, which are essential for accurate sizing but remain unresolved in the discussion.

theone!
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The problem involves a a heater and three jacketed reactors. The reactors are heated by water supplied by the heater.

Determine the heater size(in kW) required for this service if the heater is to be
sized so that it is large enough to handle all three reactors when they operate at full load


do I just treat the jacketed vessels like heat exchangers;

##\dot Q=U A_s \Delta T## with ##\frac{1}{U A_s}=\frac{1}{h_i A_i} + \frac{ln(D_o/D_i)}{2 \pi k L} + \frac{1}{h_o A_o}##

and then multiply ##\dot Q## by 3 to get the heater size?

Determine the appropriate pipe sizes for the main water supply and return lines.
the system. There should be two different pipe sizes: one for the main supply/return line and another for the lines connecting the reactors to the main supply lines.

is this just an application of

## \frac{p_1}{y} + \frac{V_1}{2g} + z_1 = \frac{p_2}{γ} + \frac{V_2}{2g} + z_2 + \frac{V_2}{2g} [ \frac{fL}{D} + K ]##

and I should solve for the diameter?
 

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The device I'm using to type this on doesn't allow me to see your equations correctly so I haven't been able to check those but..

The problem statement appears to gives you enough info to work out the power consumed by each reactor... You have the flow rate and the temperature drop and can look up the specific heat capacity of water. Multiply by three and you have the power that the heater would need to deliver.

I can't help with the pipe sizing sorry.
 
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CWatters said:
The device I'm using to type this on doesn't allow me to see your equations correctly so I haven't been able to check those but..

The problem statement appears to gives you enough info to work out the power consumed by each reactor... You have the flow rate and the temperature drop and can look up the specific heat capacity of water. Multiply by three and you have the power that the heater would need to deliver.

I can't help with the pipe sizing sorry.

thanks!

about the pipe diameters, I think I have the equation to get them but it looks like I need the flow rate of the water. (The only flow rate info I'm given is the max allowable flow rate of 50 USGPM through the jacket)

Another question of the project asks me to "determine the required pump head and flow rate for your design"

So I was wondering if I should pick some pump, plot the system curve and pump curve, get the operating pump head and flow rate at the intersection, and then use that flow rate to get the diameters?
 
I never studied this but...

The problem statement describes the pipework. It looks like there is a main supply and return which will carry 3 x 50usgpm plus branch pipes to each reactor that will carry 1 x 50usgpm each.

Its not my field but I imagine you need to make a drawing and mark it up with the flow rates and calculate the pressure losses in each section. Calculate the pressure loss around the loop including that in the heater (gives you the pump head required). That and the flow rate should allow you to work out the pump power? I think!
 
theone! said:
The problem involves a a heater and three jacketed reactors. The reactors are heated by water supplied by the heater.

Determine the heater size(in kW) required for this service if the heater is to be
sized so that it is large enough to handle all three reactors when they operate at full load


do I just treat the jacketed vessels like heat exchangers;

##\dot Q=U A_s \Delta T## with ##\frac{1}{U A_s}=\frac{1}{h_i A_i} + \frac{ln(D_o/D_i)}{2 \pi k L} + \frac{1}{h_o A_o}##

and then multiply ##\dot Q## by 3 to get the heater size?

Determine the appropriate pipe sizes for the main water supply and return lines.
the system. There should be two different pipe sizes: one for the main supply/return line and another for the lines connecting the reactors to the main supply lines.

is this just an application of

## \frac{p_1}{y} + \frac{V_1}{2g} + z_1 = \frac{p_2}{γ} + \frac{V_2}{2g} + z_2 + \frac{V_2}{2g} [ \frac{fL}{D} + K ]##

and I should solve for the diameter?
Hey, so did you end up solving the problem with the P&ID? Is there any chance you can share it?
 

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