Potential Problem of Direct Fired Heater for Crude Oil 1

[magicking]

Hi everyone,

My client insists to use direct fired heater to raise the temperature of crude oil but we insist to use indirect fired heater.

First Question: Is it acceptable to use direct fired heater for crude oil?

Second Question: If it is acceptable, what measures are necessary to allow them to operate safely and reliably?

Third Question: What is the potential problem to use direct fired heater for crude oil?

Thanks.

 

[Montemayor]

magicking:

Direct-fired heater-separators are used quite frequently to separate produced liquids as well as the gas phase in the Oil Patch. They are also used to pretreat prior to desalting the crude. The usual, horizontal U-tube is used as the firing chamber.

Answers to your questions:

1) It exists; it is being done; and it will probably continue.

2) Good engineering judgment, and proper safe design by experienced process engineers is what I would prescribe for a successful unit. The unit I designed in 2002 operated so good that the local govenment nationalized it.

3) Not applying my answer to point #2.

 

[doct9960]

magicking,

When you say direct fired heater, is the flame directly impinging on the tubes containing crude oil?

 

[magicking]

Hi doct9960,

Yes. No, I think the flame will heat the air and the air is impinging on the tubes containing crude oil.

Magicking

 

[doct9960]

magicking,

Fired heaters designed to API Std 560 are examples of heater that heats up crude oil in refineries.

http://www.heaterdesign.com/designGulf.htm

 

[magicking]

Thanks everyone,

What is the efficiency of direct fired heater. I know that for indirect fired heater, the efficiency is around 76-81%.

Magicking

 

[dcasto]

You could design a heater with effiencies in the 80+%, you'll need extended surface convection sections and even add air pre-heat via recouperation.

The lower section will be radiant heat in most direct heaters. There are some manufacturers of heaters that have designed an all air heater whereby huge amounts of air are added after the burner with fans so that you get all force convection heat transfer. This was done to decrease the probability of hot spots on tubes that could fail and create a huge fire.