fugitive emission testing and certification of valves what ...c.ymcdn.com/sites/ · pdf...

2016 VMA Technical SeminarFugitive emission testing and certification

of valves – What we will have to do next?

David Bayreuther

March 10, 2016

OutlineSources of emissions

History of legislation

Review of standards

Inconsistency in standards

What is next?

2

© Metso© Metso Date Author Title

• Primary types of sources:

- equipment leaks

- process venting

- evaporation losses

- flaring

- accidents and equipment failures

• Methane (CH4)

- predominant greenhouse gas emitted

by the oil and gas sector

- more than 20x the global warming

potential of carbon dioxide

- detrimental to public health

Sources of fugitive emissionsRefineries and chemical plants

3

EPA reports 11% decrease since 1990...but will increase by 2030 if no action taken

© Metso© Metso Date Author Title

History of legislationFugitive emissions

4

• Air pollution control act 1955

• Clean air act 1963

• CAA amended in 1970

• CAA amended in 1990 to include

LDAR

• Late 1990s, under-reporting facilities

assign dedicated management

• Late 2000s, consent decrees revised

to require low leak packing technology

• Focus is on plants to monitor and

repair

• Plants look to SDOs for help

© Metso© Metso

• ANSI / ISA S93.00.01

• ANSI / FCI 91-1

• TA-Luft VDI 2440

• ISO-15848-1 and -2

• Shell SPE 77/300

• Shell SPE 77/312

• ChevronTexaco

• API-622

• API-624

• API-641 (pending)

Numerous emission test standards are writtenFugitive emission test standards

Date Author Title5

And more to follow…isn’t this too much already….why?

© Metso© Metso Date Author Title

• Different tests for various valve types

• Emphasis on accuracy of the test

• What is an appropriate test method

- Measurement method(s)

- Helium vs. Methane

- Units of measure

- Test temperature

- Temperature range

- Number of thermal cycles

- Test pressure

- Packing adjustment allowed?

- Static vs. dynamic leakage

• Lets review some of these issues in

more detail

Confusion in the standards committeesHow do we prove performance through testing?

6

© Metso© Metso Date Author Title

• Global methods

- Vacuum

- Flushing

- Bagging

Which measurement method?Global versus local method

7

• Local method

- Sniffing

© Metso© Metso Date Author Title

• Methane

- Limited laboratories

- Non-toxic but extremely flamable

- Explosive when mixed with air

- AIT limits maximum test

temperature

• Helium

- All laboratories

- Readily available

- Not flamable

- No limit to maximum test

temperature

Testing with Helium or Methane?Safety and other considerations

8

© Metso© Metso Date Author Title

• Methane

- Units are ppmv

• Helium

- Volumetric flow units are mbar-l/s per

mm of stem diameter

- Ranges from 1,78x10-7 to 1,78x10-4

or

- Mass flow units are mg/s per meter of

stem diameter

- Ranges from 10-5 to 10-2

Units of measureCan you correlate to actual in-service results?

9

Not possible to correlate Helium to Methane…. or mbar-l/s-mm to ppmv

© Metso© Metso Date Author Title

• Goal is to verify that the seal

design will remain tight through

entire valve temperature rating

• Typically, the internal fluid

establishes the operating temp.,

and the packing and seals are

closer to ambient

• Using local heat sources the

packing box does not reach the

full test temp.

• Test in an oven and the entire

valve achieves the test temp.

• ISO-15848-1 versus API

Test temperatureIs it acceptable if the packing does not reach the test temperature?

10

© Metso© Metso Date Author Title

• ISO-15848-1

• Can require 2 tests to cover the

temperature range

• Test at room temp qualifies valve

from -29C to +40C

• Problem example with ISO-15848

Test temperature rangeWhat is ambient temperature?

11

© Metso© Metso Date Author Title

• Thermal cycles establish time

needed to complete test

• Reason for a thermal cycle

• Min. per ISO-15848 is 2 cycles

• Some standards require up to 5

• Examples of test results

Number of thermal cyclesHow many are necessary?

12

© Metso© Metso Date Author Title

• Valve rating at the test

temperature?

• API standards use 600 psig or the

valve body rating, whichever is

less

• Challenges in achieving full valve

rating

Test pressureWhat is the appropriate value?

13

© Metso© Metso Date Author Title

• Yes - it simulates the real

operating environment

• Yes – but only once after the 1st

thermal cycle

• No - it indicates a problem with the

valve design

• ISO allows one adjustment per

stage of testing

• API allows none

Is packing adjustment during test allowed?The opinions vary

14

© Metso© Metso Date Author Title

• One successful test in a laboratory

is no guarantee of future results

• Success in a laboratory does not

equal success in the plants

• Factors not address in laboratory

test:

- thermal stress

- pipe stress

- flow erosion

- vibration

- effects of corrosion (both within the

system and from outside conditions)

- mechanical wear

- aging

- environment

Despite all the work, test results are not definitiveOther factors to consider

15

© Metso© Metso Date Author Title

• Comparison between different

standards is nearly impossible

• Standards do not take into account

the process conditions

• The number of tests within the

standards is practically unlimited

- For a valve manufacturer it is

impossible to have all the

combinations covered

Summary on testingEmissions testing standards are a confusing mess....

16

But we have excellent results

Significant improvements to packing and seal materials, and

installation techniques, leading to lower fugitive emissions

© Metso© Metso

What does the future bring?

• Latest legislation changes

- Announced strategy to reduce

Methane emission in 2014

- In 2015, announced new goal to cut

Methane emissions from oil & gas

sector by 40 – 45% by 2025

• EPA is seeking expert input on

how to update and modernize the

LDAR program

• API developing a new standard for

rotary valves

Date Author Title17

More change....

Thank you for your

time and attention