High Gas Dilution - Gas Flow management

High Gas Dilution Ratio - Semiconductor Photocatalysys

Standard dictates to measure the overall capacity of the photocatalyst in removing the nitrous oxide, NOx, using an air flow containing NO and NO2 (1ppmv) within an average test time of 5,0 h in lighting condition and with a flow rate of 1.5 L/min. The level of exhaust used is about 500 ppbv. Given the low stability and the difficulty to find gas test cylinder in such low concentrations, we decided to use standard Mass Flow Controller to reduce through mixing ultrapure air at 500 ppbv of NOx tanks as balance with standard cylinders with a concentration of 400 ppmv of NO and 400 ppmv of NO2. Although, a dynamic preparation of gas mix of this type and composition control of the mix itself with a Mass Flow Controller resulted mediocre due to the long response time and the high instability, for the long duration of the test (5h), in controlling low flow rate which, in time, led to inaccurate estimates of the efficiency of the photocatalyst and to the non reproducibility of standard test conditions. The using of the MCQ GB100 Series allowed obtaining the desired concentration within the photoreactor with a flow rate of 500 mL/min using ultrapure dry Air as balance gas and a NOx mix as solute.

Benefits and Savings.

A traditional method would require at least 2 mass flow controllers, an external control unit, a power supply, and a tubing system, plus a massive investment of time in pre-mixed ppb gas cylinders. This obsolete method would not either solve the problem at its roots, because of a huge waste of time in gas delivering, and a substantial impossibility to dilute desired gas ratios with certain stability. With MCQ Instruments, the Universita’ La Sapienza required only a single Gas Blender 100 Series device and its Software in Pro Version. The simple combination of these two factors has made possible an exponential number of experiments, reducing time, efforts, investments and collecting much more results.

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High Gas Dilution Ratio

Thanks to our Gas Blenders they reached a stable flow dilution from 400 ppm to 500 ppb. Easily!

Time Savings

Because of a weak dilution stability, before La Sapienza did reach only 1 success in 15 days. With MCQ they get it in 20 minutes.

Micro-Flows. No Cut-Off

OUR GB100 Series allows you to control the flow in all the calibration range, from 0,1 ml/min to 500 ml/min with NO cut-off

Without MCQ?

Regular Mass Flow Controllers resulted to be totally ineffective for such dilution (ppm -> ppb) for the micro flow-rate. Unstable, unsuitable, entirely inaccurate.

Software Automation

Thanks to our Software PRO version and its option "Automatic Program", now La Sapienza can bring forward experiments in automation, painlessly.

Flow Stability

Thanks to our revolutionary method every gas flow has a great stability making possible to have a stable flow also for lower flow-range.