Air generator for GC

Question

We need to use air generator for 8 GCs with FID Detector. Each FID uses 350 mL/min air. So for 8 FID, 2.8L air will be sufficient? Is it ok to go for an air generator that supply 3L of air/min or we need to go for a higher option? Kindly advise

CMZainea · Answer

Hello bijishnair , 
 
 The flow in mL/min is a calculated value based on the P delivered to the FID. 
 
 I am not sure what type of GC you are using, but will use the 8890 manual below for reference. Table 17 at page 44 shows a range of 55-100 psi for air for FID detectors. Generally, 60-80 psi for delivery pressure is a good enough range for most cases, for air for an FID. Depending on the model of GC, the maximum allowed pressure on the FID might be lower than 100, so make sure to check the requirements for that if the GCs are of different model than the 8890. 
 Agilent 8890 GC Site Preparation Guide 
 
 The pressure required to deliver a certain amount of flow at one temperature is different to the pressure required to deliver the same flow at a higher temperature. So just going off of flow requirements can lead to problems further on. 
 I don't have an idea of how the air generator supplies gas to the GCs, but you need to make sure you need to deliver the required pressure to the FID (up to 100 psi per GC -if 8890-, but not higher than that). 
 
 Apart from instrument requirements, there might be other factors to take into account; such as the length of the gas lines to the GC, where the air generator is installed (same room, different room, different floor etc). The air generator manufacturer should be able to address these questions. 
 
 Maybe other users with similar configurations would be able to provide some insight as well.

shivilik · Answer

Hello, 
 2.8 L/min its 93% of productivity of air generator (if we speak about generator with max productivity of 3 L/min) and you will kill you generator soon , pump at least, because receiver will be empty all the time 
 And as CMZalnea said you should have 55 psi minimum for each GC pneumatic module otherwise EPC generate error message and turn off GC 
 
 I had experience when 3 GC works normally with generator (2 ml/min - 355 kPa +\-5% outlet pressure) - but maximum flow was 300 ml/min 
 CMZainea said: The flow in mL/min is a calculated value based on the P delivered to the FID. 
 
 I am not sure what type of GC you are using, but will use the 8890 manual below for reference. Table 17 at page 44 shows a range of 55-100 psi for air for FID detectors. Generally, 60-80 psi for delivery pressure is a good enough range for most cases, for air for an FID. Depending on the model of GC, the maximum allowed pressure on the FID might be lower than 100, so make sure to check the requirements for that if the GCs are of different model than the 8890. 
 Agilent 8890 GC Site Preparation Guide 
 
 The pressure required to deliver a certain amount of flow at one temperature is different to the pressure required to deliver the same flow at a higher temperature. So just going off of flow requirements can lead to problems further on. 
 I don't have an idea of how the air generator supplies gas to the GCs, but you need to make sure you need to deliver the required pressure to the FID (up to 100 psi per GC -if 8890-, but not higher than that). 
 
 Apart from instrument requirements, there might be other factors to take into account; such as the length of the gas lines to the GC, where the air generator is installed (same room, different room, different floor etc). The air generator manufacturer should be able to address these questions. 
 
 Maybe other users with similar configurations would be able to provide some insight as well.

Air generator for GC

Top Replies