CFD Online Logo CFD Online URL
Home > Forums > Main CFD Forum


Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   May 8, 2001, 13:09
Default HELP! About CFB
Posts: n/a

I am designing a circulating fluidized bed(CFB) at laboratory scale. I found many large CFBs use two gas inlets: a vertical primary gas inlet, where gas is blown from the bottom of the bed(air distributor),and a horizotal secondary gas inlet, which is very near the gas distributor.

Is there anyone who can tell me what is the use of the secondary gas inlet?

  Reply With Quote

Old   May 8, 2001, 14:07
Default Re: HELP! About CFB
Murat Koksal
Posts: n/a
The secondary gas injection or the so-called secondary air (SA) injection is mostly used in CFB combustors. With SA, you tend to decrease the total air flow through the bottom of the riser, you create an oxygen lean (fuel rich) region and this helps to control the fuel based NOx formation. NOx is one of the leading pollutants emitted from fossil fuel combustion systems. However, the application of secondary gas injection is not limited to combustion systems. Im fluid catalytic cracking reactors (FCC) (I am talking about CFB reactors, of course) where you produce gasoline, kerosine etc from crude oil, the feed is mostly injected laterally above the main gas inlet. This helps to increase the mixing of the feed with the bed material.
  Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
CFB modelling Umesh CFX 3 July 28, 2010 15:17
CFB boiler simulation pichai FLUENT 0 June 10, 2010 22:19
Combustion in CFB with Eulerian? HP FLUENT 3 August 4, 2005 02:57
Capacity to model CFB riser Umesh FLUENT 0 October 26, 2004 18:17
CFB in Hot model with Fluent6.0 Thitikorn FLUENT 3 July 4, 2002 08:37

All times are GMT -4. The time now is 15:04.