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Q: Thermodynamics - Power Cycle Problem ( No Answer,   1 Comment )
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 Subject: Thermodynamics - Power Cycle Problem Category: Science > Physics Asked by: megahog-ga List Price: \$30.00 Posted: 27 Apr 2006 08:35 PDT Expires: 03 May 2006 13:53 PDT Question ID: 723353
 ```Ok, here is the main objective: Design an accumulator for the following service (i.e. CALCULATE ITS VOLUME) if no more than 95% of its volume should be occupied by the liquid at any time..... And this objective must be achieved under these constraints and in the context of this information: (A STEP-BY-STEP ANALYSIS will be greatly appreciated and compensated with a generous tip. Let me know how long you spent on this and I will tip you accordingly depending on how FAST you can return an answer.) INFO: Steam power plants face fluctuating power demands all the time. Since power can not be easily stored, one solution to fluctuations in power demand is to pass variable amounts of steam through turbines to match power production to power demand. This means that either the boiler steam production is varied to match varying steam demand or alternative ways are found to manipulate steam supply to turbines to match steam demand. In this context, consider the following scenario. CONSTRAINTS: A power plant operates at 700 kPa and it has a boiler with steady steam production capacity of 6000 kg/s. The average steam demand of the power plant over the period of an hour is 6000 kg, but the instantaneous demand fluctuates from 4000 to 10000 kg/h. It is suggested that fluctuations in steam demand by the turbines can be accommodated by taking the following steps: 1. Produce saturated steam in the boiler at a pressure of 1000 kPa and operate the turbines with an inlet steam pressure of 700 kPa. 2. Add an accumulator between the boiler and the plant. An accumulator is essentially a tank containing mostly saturated liquid water that ?floats on the line? between the boiler (pressure 1000 kPa) and the plant (i.e. turbine operating at inlet pressure of 700 kPa) 3. Have a pressure control valve between the boiler and the accumulator to regulate pressure upstream of the accumulator and another pressure control valve between the accumulator and the turbine to regulate steam pressure downstream of the accumulator. The accumulator is to be designed such that (a) Pressure in the accumulator will fluctuate between 1000 kPa and 700 kPa. (b) When steam demand will be less than boiler output, steam will flow into the accumulator and will be largely condensed by liquid residing in the accumulator. In the process, pressure in the accumulator will increase to values greater than 700 kPa. (c) When steam demand will be greater than boiler output, water in the accumulator will vaporize and steam will flow out. In this process, pressure in the accumulator will decrease to values less than 1000 kPa. TIME LIMIT: 1 WEEK```
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