Air/Fuel ratio by controlling flow rates

[ddeshi2]

Hi all, I'm new to PLC Programming and this is my first project. In our project water, air and natural gas are fed to a combustion chamber and the mixture is ignited. We feed water first, then air,then natural gas. I have to control the flow rates of all the three and also the air/fuel ratio. How can I control the air/fuel ratio by controlling their flow rates? For example, Air/fuel should be in the ratio of 10 to 1 ..can I achieve it by using single PID loop.. CV of Air becomes the set point of Natural gas and the valve is opened accordingly? Am I right? Please Help..

Thank you,
Ding.

 

[Steve Bailey]

What you have described doesn't sound like a single PID loop to me. It sounds you want to use the output of the air PID loop as the setpoint for the gas PID loop. Why do you think this will give you better results than making the setpoint of the gas loop one tenth the setpoint of the air loop?

 

[Mickey]

Ratio Control..

http://www.google.com/#hl=en&sugexp...=1&bav=on.2,or.r_gc.r_pw.&fp=39e5bf4e97622fe9

 

[danw]

>We feed water first, then air, then natural gas.

The English meaning is a sequence of actions: water, then air, then fuel. If that's actually the case, ratio won't work because only one oomponent is being added at a time.

But doing so creates a chamber full of fuel and air, essentially a bomb (an explosive mixture), not continuous combustion.

What's really going on here?

 

[shawn_75]

You making a boom generator to scare off birds?