Gas Fired Boiler Steam Capacity

Yes.

http://www.ngte.co.uk/doc/doc/etf5-7l.jpg

He is also maybe trying your engineering skills. Best is to avoid being caught unguarded - look for another job!

Hire an engineer.

Header located at consumer premises?

Does your consumer consume continuously, infinitely variably or intermittently?

When you say "not as per design" do you mean the design was ignored during procurement and construction or do you mean that the (already implemented?) design doesn't perform as anticipated..ie fails to meet or exceed specified performance parameters?

Looking for a patch?

STOP!! Look for another job, you are not qualified to handle this alone, with hurting or killing somebody!

So give her the explanation she wants! Strewth.

You need to be much more precise before anybody can help. What do you mean by a steam header? How will it help solve the problem? Is total boiler output enough for the 1 km consumer plus other demands? Of course the supply pipe must be properly spec'd for the steam flow and pressure required.

We have 11 gas fired boilers,steam pipe from each boiler is connected to one 24 in dia pipe to steam user.On the user's side they have a steam header.On our side,,there is no steam header to store steam from each boiler before being sent to the user.Understand the project was a mess before I joined..now i have to wash the shit.At one point the steam pipe was designed with sudden or abrupt change of direction..I believe a curve is better to avoid steam hitting the pipe wall.drop in pressure,change its direction of flow,slowly pick up the pressure.At this low pressure region they have PT and claimed that the pressure has dropped below agreed figure..then a penalty on us.Same goes to boiler capacity,The user request 90 tonnes,,we run 7 boilers,still the steam pressure dropped to below 14 bar..minimum required by user..boiler design pressure n capacity is 18 bar n 16 t/hr respectively..can anyone help me to keep steam pressure 15 bar not 14 bar..thank you.

Your pipe is your header in this arrangement.

What is the pressure in the pipe/header at the boiler end. Does it stay steady at 15 bar?

or go up and down alot?

Your opening paragraph is what I get and that's what has me wondering about what's actually happening, aka reality, at the boiler end of things.

As the poor OP said he inheretted a mess, could be a lot of things. Start at one end....

Now when you have 7 boliers working into a header the output is not 7x 16t/hr all the time.

Whenever one of the boilers is charging with water it cools down and you effectively loose that 16t/hr until it gets upto working pressure again, and 6x16t/hr is only 96t/hr...close.

With 7 boilers running there is a high likelihood that more than one boiler might be recharging simultaneously and then your budget is way short......and if there aren't any check valves between each boiler and the header pipe then watch the pressure in all the boilers drop whenever one boiler is refilling.

If you start off short all bets are moot.

Most continuously operated boilers have continuous feed-water supply to the steam drum (if indeed they are single or mutiple drum designs), and also feed-water has to be continuous in drum-less once through designs using evaporator coils. OP has made zero mention of the boiler design. If these are utility class boilers, then there are most likely several feed-water heaters to ensure no cold shocking of the boilers.

The more likely scenario is loss of steam production through deposits on tubes, poor condition of tubes, boiler leaks, or sooting that has not been dealt with appropriately, and all of these may represent seriously dangerous conditions that could leak to a general boiler episode that will possibly put life and limb in jeopardy, much less meet the output requirements.

OP needs to try to obtain any and all records of boiler maintenances that have been done, inspection records, records of any boiler cleanings, along with fuel efficiency records. If he can prove the problem is on his company's end of the line, then there should be a clear pathway forward for him to solve this problem by "cleaning up the poop". A little knowlege is a dangerous thing. A lot of knowlege is a powerful thing.

We are still doing a fair bit of guess work with this operation but

15barg steam is saturated at 201C so assuming some superheat at 230C

Density = 7.43kg/m3 hence 90te/hr = 3.365m3/s

24" pipe id = 0.61m so area = 0.29m2

Giving a velocity = 11.6m/s which looks ok

Using an online pressure drop calc I get 0.1bar pressure drop for your 1km line. This feels a little low but at this low velocity is going to be about right

So it looks as though the steam header is not the problem.

You talk about a sharp deviation but its not clear what you mean by this statement. My experience has been in oil and gas plants and a typical short radius 90degree elbow is equivalent to 20 - 30 m so it wouldnt have a huge impact.

Reducing the pipe size though does have a significant impact.

I wonder if there is a problem at the users end that the off take control does not allow them to maintain a pressure in the header.

With the much lower flows in some cases there is almost negligible pressure drop and so the issue is either that your boilers cannot supply at the required pressure or that some aspect of the users means that they cannot maintain a back pressure in the header but unless we know some of the detail at the user and at your end this is just stabbing in the dark.

So, Rosli. How are you getting on with this?