Gas Material, Processing and Power Technologies
The purpose of development
Conventional type calorie measurement instruments are inevitable of measuring time delay caused by gas sampling. Sampling delay causes sometime failure of following to drastic calorie change. Therefore Osakagas has developed the quick response inline type ultrasonic calorimeter, aiming at realizing quick response with high accuracy getting rid of sampling time delay.
Outlook of ultrasonic calorimeter.
Advantages of quick response calorimeter
Osaka gas has developed inline type ultrasonic calorimeter based on the principle that an ultrasonic velocity passing through the gas inside the pipeline is affected by molecule weight.
The advantages of this meter are as follows.
- Quick response (less than 1 second)
- High accuracy (Plus minus 0.4%)
- Applicable high pressure (Maximum 10 MPa)
- Get rid of gas sampling and dispose
- Calorie and flow rate can be measured simultaneously
- Without pressure loss.
The principle of measure
Generally a sonic velocity passing through in the gas is affected by molecule weight.
Here, Cp is constant pressure specific heat value, Cv is constant volume
specific heat value, R is gas constant, T is temperature, and M is molecule
weight.
Above equation, molecule weight is gotten by measuring the sonic velocity
passing through gas. Then Gas calorie is known using the relationship
between molecule weights and calories. But town gas is consisted of several
components; so the sonic velocity is influenced by consist of components.
So, Osakagas made up calorie calculation algorithm that is applicable
for multi components gas such as town gas.
Field test
Since 1997, Field test had been practiced as installed developed calorimeter for the operating gas pipeline at Osaka gas Himeji terminal. And the results are as following.
- Responsibility: Ultrasonic calorimeter has no considerable time delay. Compared with conventional calorimeter that is settled next to ultrasonic calorimeter, around 90 second quicker. (Refer to following figure)
- Accuracy: Confirmed that it is less than plus minus 0.4 %
- Stability under long-term usage: There is no periodical data fluctuation and also there is no influence of ambient temperature and weather
Conclusion
Quick response of developed ultrasonic calorimeter contributes to stable calorie control therefore contributes to improving gas quality. Because this meter can measure not only calorie but also flow rate, and no need sampling equipments include governor for pressure reduction, it will contribute to construction, operation and maintenance cost saving.
