3 replies to this topic

[sameera92]

Hello!

 

I'm working as a chemical engineer in a petrochemical company; recently joined. One of the issues I have to solve is the poor tank gauging system we have in place.

 

We are using RADAR based ATG system to measure daily chemical controls of our chemical tanks (10) which are of about 10m in height. This is done by manual dipping which takes about 2 1/2 hrs of the operator's time per day. We are also facing some lack of manpower in this area which makes this time valuable. Further, the ATG systems are re-calibrated every 6 months.

 

The readings taken from ATG system and manual dip reading are about 50mm - 100mm differing which is 0.5% - 1% error. This is not satisfactory because our company's tolerance limit is 0.5%. Therefore, we have been limited to do the stock measurements using the manual gauging, and this becomes troublesome if we want to take additional measurements after daily uses.

 

I checked about RADAR based ATG systems from the suppliers and internet, but the best accuracy is 0.25%. This is not good because only 0.25% extra error capacity is there for all the inventory. CAPEX is also an issue therefore expensive alternatives with better accuracy is difficult to purchase.

 

I want to know,

a) Is this the same case with other plants that you are working in? Esp. in oil and gas industry?

What are the tools/methods that you employ to mitigate this issues?

 

Thank you!

[breizh]

Hi sameera92 ,

Why do you give more credit to your manual gauging ? Normally the accuracy of radar is good ,a few mm .

Why do you need such accuracy , is it for stock management?

 

http://www.motherwel... gauge-1-1.html

 

Breizh

Edited by breizh, 12 December 2015 - 08:20 PM.

[Art Montemayor]

I agree 100% with Breizh.  His comment matches my personal experience in the field when, over a span of a couple of years, I replaced mechanical level detection devices with radar (microwave) type of level detectors.  I did this in the 1990s after running several months of testing the accuracy, dependability, and costs of many devices and discovering that radar gave us accuracies in the mm of level readings – a result that beat all other measurements.  I also justified the replacement of all storage tank detectors with radar because it was proven to be cheaper than the other devices – on a total, installed, calibrated and operating cost.  It simply was cheaper to install the radar as well as to maintain it – with zero human entry required to the tanks and vessels involved!  This last feature was the “straw that broke the camel’s back”.  We never went back to any other type of inventory measurement – and that was 20 years ago when the radar instruments were being developed into what they are today.  So they were more costly and less developed than today's models.

 

I would expect even more accurate and cost efficient results today, bearing in mind the increase in manual labor and the competitive quantity of suppliers of this type of equipment.  The experience I had was with Endress+Hauser instruments, a pioneering company in the field at that time.  I wouldn’t use any other type of level detection today for static measurements – and I’ve also used this for constant, real-time read outs of changing levels, with recordings of inventory changes, management, and accounting.

[manojkaila]

Sameera,

 

In ATG there are many factor in the system. Many type of correction for exact measurement. Pl check with your vendor all that setting and calculation. Some time by changing this data you will get batter accuracy. Check you stepping table for the tanks & what is loaded in the system. Still many location for stock purpose people are preferred manual dip.   

 

Regards,

 

Manoj