Questions tagged [steam]

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Why doesn't steam/water flow backwards from expansion in power plant feedwater pump/boiler? [duplicate]

I think i understand the mechanics in a steam locomotive: Fill boiler with water Close off boiler Heat boiler until pressure is sufficient Keep boiler hot and use steam pressure until no more water ...
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2answers
60 views

Why use steam water and not other fuild in steam engines?

Given this answer, I understand the importance of phase change (liquid --> gas) for the fluid used in a steam engine. Thus I understand it is important to use a fluid that is liquid at pressure and ...
23
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8answers
9k views

Why use steam instead of just hot air?

As I understand, a steam machine needs a pressurised gas to work. This can be compressed air but it used to be steam. Energy was provided to the steam engine by heating up water. I don't understand ...
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1answer
77 views

What's this box in steam locomotives?

In the past few weeks I've seen several European steam locomotives in museums. I noticed several of them have a box in the driver's cabin, similar to the one in the picture I've attached. Several ...
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1answer
52 views

pH calculations for boiler water

For water steam cycle in a "combined cycle power plant" containing 3 boiler drums and dosing of 5% ammonia solution in the condenser. How can I calculate the pH of the boiler water in each of the ...
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0answers
42 views

How is a Steam Power Plant designed?

I asked this question at physics but i think this suits it more. I'd like to know few things about how does one design a Thermal Power Plant? There is something fundamentally lacking in my knowledge ...
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1answer
364 views

Pressure Temperature relation of saturated steam

With the saturation pressure apparatus we did a heating and a colling process. We measured the temperature and afterwards we calculated the specifc volume of saturated vapour. The question 1: What ...
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1answer
102 views

Saturated steam equations

I found the following paper and am attempting to put Saturated Pressure and Saturated Temperature into excel. I got Saturated Pressure to work, but can't get saturated Temperature to work. Saturated ...
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2answers
72 views

How can energy be added at constant temprature?

In the answer to this question: Difference between Saturated Liquid and Saturated Steam How can energy be added with constant temperature? Isn't the energy input itself a change of temperature? ...
19
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6answers
6k views

Why did steam locomotives not transfer power by cogwheels?

Modern cars use cogwheel to transfer power from the engine to the wheels. Steam locomotives used some kind of bars (sorry, I'm not a native speaker) to transfer the power to the wheels. Why did the ...
3
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1answer
450 views

estimating the surface area of a steam coil immersed in a tank

I've been tasked to design a steam coil that will be immersed into a tank in order to maintain the fluid temperature above 25C (but not to exceed 40C), and I need to calculate its surface area & ...
2
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1answer
89 views

How did the snifting valve in Newcomen's steam engine work?

Its function was to expel the air that came inside the cylinder along with the steam to prevent the engine to become "wind logged". Since the valve was non-return, how did Newcomen stopped steam from ...
0
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1answer
269 views

Determining gas properties in a steam and air gas mixture

I have a gas mixture (steam and air) contained in a tank. I know the tank pressure ($P$), temperature ($T$) and the massic air fraction ($x_a$). I would like to determine the density of both gases ...
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1answer
2k views

How to calculate saturated steam flow rates?

It has been a while since I had thermodynamics and am attempting to solve this problem for work. I need to figure out the other two mass flow rates. I worked it out with specific heats, but don't ...
2
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2answers
120 views

Why is more steam required to turn a steam turbine when electric power consumption is higher

I'm recently under industrial training at a plywood mill. My supervisor is from foreign country so there are some difficulties for me to understand what he is trying to say. In the power plant, the ...
3
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1answer
181 views

Is Vapor Compression Distillation inherently more efficient than a thermal-only boiler-condensor?

I'm having a hard time understanding the benefits of VCD (like Slingshot) over a conventional boiler in terms of volume of condensate produced per unit of energy input. I've found quite a few ...
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3answers
210 views

Rate of flow of steam going from one pressure to another

A closed steam boiler in a coffee machine idles at around 124 °C, the steam and water inside at 1.2 barg. When a steam valve is opened, steam rushes out through a steam wand inserted in milk, to ...
6
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1answer
367 views

How to protect a pressure gauge from condensation in a vacuum steam boiler?

Pressure gauges are protected from steam condensation in a regular boiler by using a siphon where steam condenses and prevents steam from going further up to the gauge. However in a vacuum steam ...
7
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4answers
250 views

Why do steam and diesel engines have differing cylinder configurations?

Consider a fixed steam engine, such as in a Lancashire cotton mill or pumping in a Cornish mine. Then consider a fixed diesel engine such as a large generator or ship's engine. Why does the steam ...
2
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1answer
379 views

Calculating the Fraction of Steam in a Mixture

I have a stream ($10,000$ $m^3/d$) of inert gas and steam. The temperature of the stream is $195$ $^oC$, and the absolute pressure is $1455$ $kPa$. I am trying to find the amount of steam that can ...
4
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1answer
611 views

How many blades for a steam turbine?

I am building a very simple turbine that runs on steam. I want to make it as simple as possible, thus avoiding impulse and reaction turbines. I want to design the turbine to fit in an exhaust pipe (...
12
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5answers
2k views

Why is using steam to rotate a turbine more efficient?

For example i have an exhaust pipe with very hot air from burning biofuel, and i have a turbine at the end of the exhaust that rotates and generates electricity. Why is it more efficient to use the ...
9
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3answers
2k views

How in Rankine cycle the turbine generates more power than the pump takes?

In Rankine cycle there's the boiler where water gets boiled into overheated steam. On input there's a pump that delivers more water, and on output there's a turbine that picks up the energy of the ...
0
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1answer
4k views

Calculating the heat energy supplied by a superheater

I am answering this question: Steam enters the superheaters of a boiler at a pressure of 25 bar and dryness of 0.98% and leaves at the same pressure at a temperature of 370 °C. Calculate the ...
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0answers
98 views

Steam Turbine - is it possible to run starting ejector and main ejector simultaneously for better efficiency?

In a steam turbine, is it possible to run the starting ejector of the surface condenser along with the main ejector? Will it improve the efficiency of vacuum generation?
6
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2answers
339 views

Pipe seized to inaccessible coupling - how to attach a new pipe?

A friend of mine that doesn't use the internet much runs a commercial laundry. They use an old 'Manlove Tullis' laundry calendar (c. 1980) that looks like this: (click to enlarge photos) ...
10
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1answer
583 views

Steam sterilization of whey in a bioreactor

I'm trying to design a bioreactor to produce citric acid with whey and Aspergillus Niger. The first step in the process would be to put whey into the reactor with some dextrose (approx. 10%). Then, ...
2
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1answer
95 views

What is the name of the part that allows a steam wand to have a moveable joint?

On espresso machines, there is some kind of pipe joint which allows the steam wand to move while maintaining its seal. What is this component called?
3
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1answer
151 views

How can I fit a DN16 flange to a DN10 flanged pipe?

One of the valves on my 3 bar line just failed. Without it, our production has ground to a stop and we can't operate until we get a replacement (which we have already ordered). In order to make a ...
11
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4answers
908 views

Preventing condensate backup at startup with orifice (venturi) steam traps on medium pressure batch process mains?

I am working with 1" medium pressure steam mains (45 psig) for a batch process. Time between batches is usually short (to the order of minutes) but depending on the day the delay can be hours, and ...