TEG / Water Boiler

[thexder00]

I'm working on a project that is looking to use TEG as a heating medium to produce <50 psig steam from indirect heating of boiler feed water in a "package" type boiler (initial thoughts are tube-in-shell units). I've found plenty of information about glycol reboilers used in the gas dehydration cycle, but these don't appear to be the service I'm looking for (the reboiler's purpose appears to be final separation of water from the rich glycol to produce lean glycol, not to produce water vapor using glycol as an indirect heat source).

I have two questions:
1.) Are there manufacturers that can provide such a "package" type boiler system?
2.) Could anyone provide me some information for said vendors?

I would like to avoid designing the boilers myself do to liability and process risk, thus I'm seeking vendor with experience in this field.

 

[Montemayor]

You seem to have a simple project. However, you don’t tell us key information: where are you located and what capacity of steam generation are you designing for?

What you are trying to describe is lost in your description of a TEG natural gas dehydrating reboiler. To answer your first question, yes, the kettle type of reboiler is a popular model for generating low pressure steam. However, it depends on the capacity of the unit. Look at the attached brochure that describes a generator like you are envisioning. The kicker is that this unit is designed and fabricated in Malaysia. If you live there, then it is who you should be talking to. If you live in the USA, I don’t think this brochure is of much use to you other than confirming that kettle TEMA type units are used for your purpose.

The answer to your second question is found in going to Goggle and typing in “waste heat steam generator”. You will get tons of hits on potential suppliers.

Another piece of advice I would pass on to you is to obtain a heat exchanger data sheet and fill it in completely, giving all the basic data it is designed to convey. This completed data sheet is the prime document used in soliciting information and / or a quote from a supplier.

Good Luck.

 

[thexder00]

Thanks Montemayor,

The project will be in the Canadian oil sands and we're looking for 10,000 PPH (or 10 MM BTU/hr) steam generation.

Local supply is preferred, but we're sourcing equipment out of Asia for other parts of the project, so that's not a terribly big issue.

Are there any process risks associated with using TEG as a waste heat source (i.e. fouling from too high of heat transfer flux, high viscosity issues, etc.)?

Thanks again for the response.

 

[Montemayor]

TEG doesn't start to "degrade" until it gets to 400+ oF, so if you are keeping the TEG as a heating medium under 400 oF, you normally should have no problems. Of course, I don't know exactly how you plan to obtain the TEG at that temperature and where it is going. Normally, I would expect a conventional heating medium - such as Therminol - but if you can justify using the TEG, I don't see anything wrong with it. I've used TEG in gas dehydration reboilers continously at 400 oF without any problems. Of course, others who didn't control their TEG conditioning and purity have had many problems. Control of pH and impurities is essential as well as avoiding any "hot spots" in the heatup of the TEG that could locally cause temperatures in excess of 400 oF. You haven't said how you intend to get the TEG to 400 oF, so I have to assume you will use a direct-fired heater. If so, the proper design of such a heater is essential to an organic fluid such as TEG.

You say supply outside of Canada would be no problem; how then would you carry out a witnessed FAT test of the finished product? Foreign supply is not bad; what is bad is the need to organize and carry out a quality control and assurance of specified and expected fabrication methods and standards. You should have an abundant qualified list of suppliers in Canada that could do this fabrication.