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steam boiler pressure

steam boiler pressure

steam boiler pressure

(OP)
If the plant requires 10 barg steam, what would be pressure of steam boiler?
are there any rules?

RE: steam boiler pressure

You are missing the entire picture here, Rika ... Yes, there are rules and industry practices for steam and boiler systems

It seems that you need a complete engineered Plant and steam/condensate system based on a correct heat/mass balance !!


It is very easy to ask simple questions that cannot be simply answered .. for example: "This man has a fever, what should be done ?

The answer, of course, is "It depends"...

What would be the pressure of the steam boiler ?.... Why, somewhat greater than 10 bar !!!

MJCronin
Sr. Process Engineer

RE: steam boiler pressure

MJCronin makes good points for a detailed design. However, for the initial scoping of a project (especially an entire plant design), it is likely that there are good rules of thumb that exist for utility supply distribution headers.

Economical design, balancing capital and operating expenses, usually pigeonholes many designs to a fairly tight window. For Rika's example, I doubt the answer would be "supply it at 30 barg" because that would involve excessive expenses.

There are obviously some factors that could change the normal design window, such as extremely long distances between boiler and users, but wouldn't you agree that a usual design window at the boiler for a 10 barg required supplied pressure may be in the 11-15ish barg range?

Rika, there are no hard and fast rules. You need to balance the operating expenses of higher pressure drops with the added capital savings of smaller pipes. Having a generalized plant layout and required steam usage (including startup, shutdown, peak capacity, and minimum usage) would be needed to begin to rough out a design.

RE: steam boiler pressure

(OP)
client has steam boiler 15 barg. but the whole plant uses 8 barg steam. there is a simple steam reducing valve just after the steam boiler reducing steam from 15 barg to 8 barg. PSV is also at 8 barg. no heat recover or anything. Condensate tank is 0 barg 80ºC.

The steam/condensate header is around 300m, size is big enough, no visible pressure drop (<0.5 bar).

So I asked why you made a steam boiler at 15 barg? client said that's the rule. but I couldn't find anything.

client heats up 80ºC water to 200ºC steam and reduces to 175ºC. In my opinion it is quite big lost, especially, these days engergy price is super high in europa.

RE: steam boiler pressure

Rika ....

Ahhhhh more information !!! ...Let the information drip begin !!! Only ten or fifteen more back and forth questions and message messages before we know your complete problem !!

First, I stand by everything I said above ... If you give us almost zero information, don't expect an elaborate or detailed answer !

Second, I stand by my "man with a fever" metaphor (look it up)

Third, I repeatedl warned you about evaluating an ENTIRE steam and condensate system and you will find out what you want.... You do not seem to be able to grasp this, Rikky

Fourth, You stated "So I asked why you made a steam boiler at 15 barg? client said that's the rule. but I couldn't find anything" ... The last place to look for information is the client... don't listen to any third world "client thumb rules"

Saturated Steam boilers are constructed and guaranteed to provide at design flow at a slight variation in pressure. A competent engineer will design his steam system for a variety of steam distribution conditions and evaluate maximum velocities under all conditions...

With the usage of VFD controlled feedwater pumps, your 15 barg (design)boiler may be a good or bad choice ... we just don't know ... an entire system evaluation is required by a compentent experienced engineer...

Sometimes steam systems are limited by maximum velocities of control (and other)valves. Pushing higher pressure steam through the system may cause noise and/or erosion problems downstream.... Components can fail

Sometimes steam systems have remote pressure reducing stations that will require rework ... we just don't know

So now we know that "We have a man with a fever, he is not awake, lying in the street, was playing with snakes and has marks on his
arms"

Anxiously awaiting your next clue

.... only 12 more postings until we get the whole picture, Rikky


MJCronin
Sr. Process Engineer

RE: steam boiler pressure

Reducing pressure through a control valve doesnt result in energy loss, since the dp is adiabatic-isenthalpic (ie there is no work energy extracted out of the stream). So 15barg sat steam is dropped down to superheated steam at 8barg. If you use a desuperheater (which has an additional feedstream of BFW), you could make more mass of sat steam at 8barg.

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