Poppy and the Steam Forum and Power Forum

Welcome to the steam and power forum, a bulletin board dedicated to questions and answers to Steam Plants and Power Generation Plants for steam boilers, turbine generator and heating problems. Dedicated to power plants, power generation, supercritical, and heating plants as well as steam boilers, steam turbine generators, gas turbines or combustion turbines, hrsg, steam heating, pressure vessels, steam line, including ASME questions and more. Remember the forum is made up of volunteers from experts to beginners. Unfortunately, we cannot allow free commercialism that promotes products, services, or sites.
The Steam Forum and Power Forum is being sponsored by the following:
Industrial Training School - Main Distant Learning
Poppy   Steam Forum  

Ross Burns on Furnace Forced Cooling

By: Ross Burns [390] 5 Stars
Date: Wednesday, December 20, 2017
Time: 11:02:35 AM

I do not think this can be simply answered. As you know, the thermal or temperature gradient is influenced by the shape, size and localized heating or cooling. I know you used a thick drum for an example, but the results will be different for the dry tubesheet that is perhaps half an inch or so in thickness. None the less, a slow air cooling is about what I would consider safe and we would use insulating blankets to slow it right down to a really safe cooling, for as your said they have a long deliver time and are expensive. I am not familiar with the temperature gradient of 40F per inch, which maybe safe for your application. With this said, and in general, thick low carbon steels that have a delta T of 400F per inch will experience a strain of about 0.001 inch per inch which places a stress of say around 30,000psi, which is a problem when the pressure vessel also has an internal pressure adding to the stress. However, if the vessel is no live loads like internal pressure and has a yield stress of 50,000 psi then the cooling rate is safe.

The ASME piping code allows cooling rate from heat treating at a maximum of 600F or less per hour per half the maximum actual thickness of a weld. But we must do our home work not to get to close to the yield point otherwise it material will rupture, which is your point. We based the temperature that is safe but in no case great than 600F. Also, fancy steels will have a different cooling parameters.

In thin walled pressure vessels like the vertical firetube boiler the safe thermal gradient is relative the distance from the hot spot since the thickness is heated with a lower delta T. We have this problem with medium and high temperature hot water piping systems that hump when the water is thermally stratified, for we can exceed the yield strength and dangerously ripe the pipe.

It will be wrong to give a rule of thumb when working with temperature gradients per inch, unlike the temperature of microstructure change is around 750F for low carbon steel, which is used in the vertical firetube boiler.

I also cannot imagine someone adding or immediately immersing cool feedwater to a dry tube sheet that is at 600F at the steam-side for fear of some surface hardening or localized distortion of the rolled joints. I maybe over reacting, but I would at least consider investigating it metallurgically.


Viewed 355 times
Published on steamforum.com



There are three-methods to find all the replies to this steam or power forum question or answer: 1) Use the 'Next >>' or '<< Previous' menu links above, or 2) Look at the year of the post and click on the applicable year an scan the postings for the date/title, or 3) Use the 'View Post Tree' feature, which is new to help you find all tree-truncations to the postings and replies on the steam & power forum that you are interested in.

VWO, BMCR, TMCR, Full Load and Base Load
By: Jim Watts [764]

MCR is maximum continuous rating.

BMCR is the Boiler MCR, TMCR is the turbine MCR

VWO is valves wide open and at normal pressure allows the turbine to exceed TMCR by 5-10 percent

Full load is not fixed but means the turbine has reached it intended maximum

Base Load is also a flexible number and means the turbine will not be operated below that figure. It is mostly used in power system scheduling where the cheapest plants run fully loaded and are referred to as base load plants. O....   Read All
Advertising Info - Click Here!

It's hard not to look at this ad at least once, then you go to the next page an notice it again. Maybe you will not read the message, but you will be thinking about the brand and we call that brand impressions.

About 2/3 of internet traffic is useless traffic and consist of malicous-bad-robots.  However, there are good robots too.  We block bad-robots, and allow the good one's through, but we just do not count the good one's.  We want good straight-brand impressions for our advertisers!

Imagine your static or animated display advertisement placed here, and if that is not enough you can include text too to expound on the virtues of your services and or products.    In addition, you can benefit by using our new advertisement feature to have your video included in your ad space.  Wow, make an infomerical with text and a display by combining all features to enhance the readers or audience's experience using your brand.  Ads can be much more than a static display ad. Here is an example of how your video could be used or position in this ad space:


Caption: This public domain video shows the benefits of Gimpel® steam turbine protection valves include trip, trip throttle, and non-return valves. The author of the video is not an advertiser and is being used to show how the video ad can be of value to the reader since you have already being viewing the video.  It is hard not to think about the authors brand after viewing the video ad.  This is the benefit of Branding.




A Long-Game that Earns Tomorrow's Sales

Click on this Promotional Advertisement to Contact Us Today!

Good Branding Puts Your Brand or Company in the Front of a Decision-Maker’s Mind for a Purchase either Months from Now or Five-Years in the Future.

Good branding makes your brand or company the leader in a crowded field of other brands or companies vying for your potential or existing client's attention. 

An invitation to the buyer's table to negotiate potential sales from $thousands to $millions of dollars in any of these: Systems sale, Capital Equipment, Upgrades & Modifications,  Repairs, or Capital Project becomes easier now with a recognized brand that thinks forward by brand advertising.

Your advertising will cost you an unbelievable low amount.  As an example this advertising space only cost $800 per month and you receive up to 13k-impressions per month and we only charge you for just 8,000-impressions per month for this spot. You get valued impression for we filter out bots when counting your impressions.

Below is some of our demographic data for steam and power forum users will speak for itself:

Bus Sector Percent   Education Percent
Manufacturing 11%   College 51%
Power Gen 20%   Grad School 20%
Chemical & Petroleum 15%      
Medical Facilities 6%      
Pulp & Paper / Forest 7%      
Pharmaceutical 7%      

Our network works hard for you with placements for full coverage on part of the network, or full network placement.  Brand yourself today and don’t miss-out on being invited to your client or future client's table because they forgot you.  Be the leader they will remember and be part of their capital project.  Tomorrow’s clients are your future.


Advertising and Marketing Agency for the steam and power forum
PE Marketing, LLC


Industrial Training School
Industrial Training School - Maintenance
Industrial Training School
National Assoc of Stationary Operating Engineers
Confidentiality, Disclaimer; Policy
© 2001 to Steam Forum, All Rights Reserved.
PE Marketing LLC is representing the steamforum for advertising and marketing
Valid XHTML 1.0 Transitional