SISGAS, a Spanish project for the optimization of measurement in networks of transport of precious fluids, Natural Gas

and petroleum derivatives

2

Index

• General presentation of the project

• Justification of the need for the tool

• Evaluating measuring instruments

• Some Illustrative Examples

• Theoretical fundamentals of natural gas network modeling

General presentation of the project

3

• Duration of the project 2011-2015

• Project certified by CDTI

• Supplier Circle

tecnología

Justification of the need for the tool

4

Justification of the need for the tool

• Degradation: The instruments always get worse.

– Aging.

– Fault.

– Variation of environmental conditions.

5

• Things to consider about the above.

– Probability of occurrence.

– How to predict it.

– How to prevent it.

– How to detect it.

– Its impact and consequences.

– Possible correction after happening.

Justification of the need for the tool

6

• Fiscal and practical issues force us to measure the best we can. • In the long run measuring badly costs a lot of money. • We care more about the relationship between data and its evolution than what its

instantaneous values are. • We must implement and take advantage of the redundancy, either direct or indirect

between the various instruments. • The auxiliary information provided by the USM is of extraordinary value when

making diagnoses.

• Data analysis and processing tools help the expert's clinical eye.

Justification of the need for the tool

• Benefits provided by supervision: – Economic.

• Use cheaper equipment. • Minimize calibrations. • More agile reaction. Less economic impact. • Ability to reverse errors.

– Of security. • Accident avoided = Savings. • Confidence in measurement = Less risk when deciding.

– Process and service quality. • Avoid repairs and calibrations = Fewer interruptions.

7

• Detect corrupt instruments as soon as possible

• Detect non-diligent performance attitudes by instruments.

• Implement "Preventive Medicine"

• Deploy "Forensic Medicine"

8

Evaluating measuring instruments

Evaluating measuring instruments

9

10

Evaluating measuring instruments • USM: A clear example of an instrument that informs about his health

11

Evaluating measuring instruments

-Distributed System - Hierarchical by geographical area - Hierarchical by type of measure

CLIENTE

CLIENTE

CLIENTE

CLIENTE

12

Evaluating measuring instruments

• How moisture has evolved in the system?

13

• Looking at the data in another way helps

• How moisture has evolved in the system?

• Maybe that's clearer?

Evaluating measuring instruments

Some examples. The case of periodic thermowells

14

Some examples. The case of periodic thermowells II

15

16

Natural gas networks dynamic library

COMPONENTS: - Gas Pipelines - Compression station - Regulation and measurement station - Branching and pipe joint

• The variables mass, velocity, pressure and temperature are a function of both the time and the longitudinal coordinate of the pipeline. It is assumed that in the radial direction there is no variation of these variables.

• It is considered that the fluid (natural gas) circulating inside the pipeline is formed by a mixture of 12

compounds.

• It is supposed to work with real gases.

Dynamic pipeline modeling

Componente Abreviatura

Metano C1

Etano C2

Propano C3

i-Butano i-C4

n-Butano n-C4

i-Pentano i-C5

n-Pentano n-C5

Hexanos C6

Heptanos C7

Nitrógeno N2

Dióxido de carbono CO2

Ácido sulfhídrico H2S

17

Tabla 1: Composición del gas natural.

1. General considerations

Dynamic pipeline modeling

• Conservation of the mass between the inlet and outlet of the pipe.

• The mass and gas velocity depend on both the time (t) and the longitudinal coordinate of the pipe (x position).

18

2. Global Balance of Matter

0)(

x

mv

t

m

m(x,t): gas mass (Kg) v(x,t): gas velocity (m/s) t: integration time (s) x: longitudinal coordinate of the gas pipeline (m)

• The fluid carried by the pipelines is a compressible fluid with a non-ideal behavior so the following state equation is used for real gases The fluid carried by the pipelines is a compressible fluid with a non-ideal behavior so the following state equation is used for real gases:

Dynamic pipeline modeling

19

6. Equation of state of real gases

n: Number of moles of gas (mol) Z(x,t): compressibility factor (dimensionless). Obtained by the method of Sarem. R: constant of ideal gases (Pa m3 mol-1 K-1).

ZnRTPV

Dynamic modeling of compression stations

20

• Compression stations are used to recover the loss of pressure that is occurring in natural gas distribution networks. In these installations the gas pressure rises up to 72/80 bar, by means of compressors, usually centrifugal.

ASPIRACIÓN IMPULSIÓN

TURBINA

COMPRESOR

RECIRCULACIÓN

21

ERM dynamic modeling • The regulation stations are located at the delivery points and in them the gas pressure is reduced to 16 bar,

as an initiation of the process of adaptation to the final pressure to which it is used by companies and individuals, which can lower up to 20 Milibar.

CALDERA

INTERCAMBIADOR DE CALOR

REDUCTOR DE PRESIÓN

MEDIDOR

CONCLUSIONS

• The simulation of gas networks presents great advantages:

- Information on many variables that are not normally measured.

- Predict Gas Behaviors, What if ..?

- Monitoring the quality of natural gas.

- Stock control.

22

THANK YOU VERY MUCH FOR YOUR ATTENTION!!

23

tecnología