# Attachment Y

Pneumatic Devices

Ned Jerabek

New Mexico Environmental Department

### OIL AND NATURAL GAS SECTOR PNEUMATIC DEVICES

5.0 CHARGE QUESTIONS FOR REVIEWERS

1. Did this paper appropriately characterize the different studies and data sources that quantify emissions from pneumatic controllers and pneumatic pumps in the oil and gas sector?

COMMENT: Yes , I am happy to say this one was the most understandable. T he studies were directly applicable and therefore the emission factors developed from the data followed logically.

2. Please discuss explanations for the wide range of emission rates that have been observed in direct measurement studies of pneumatic contro ller emissions (e.g., Allen et al., 2013 and Prasino 2013). Are these differences driven purely by the design of the monitored controllers or are there operational characteristics, such as supply pressure, that play a crucial role in determining emissions?

COMMENT: The fact that the Allen study “consisted of a mix of intermittent and low bleed controllers. No high bleed controllers were reported ...”, and the Prasino study “centered on high bleed controllers” by definition is going to result in very differ ent range s of emission rates. The Allen study also notes “that there is a significant geographical variability in the emissions rate from pneumatic controllers between production regions.” The Allen study only covered production sites in

the United States whereas the Prasino study was conducted in British Columbia, a much colder

climate. It would seem likely that the expectation would in fact be that a wide range in emission rates

would be observed . Unfortunately that does not tell us whether the wide range in emission rates is driven by climatic and geologic conditions, or operational and system design characteristics. If the studies are going to focus on a narrow range of pneumatic controllers

, then only studies that focus on the same narrow range are goin g to give meaningfu l data to compare, i.e. compare oranges to

oranges

. There doesn’t seem to be a clear definition that distinguishes between intermitten vent
controllers and continuous bleed controllers. Vent controllers have a mechanical barrier between the supply gas and the end device, while bleed controllers maintain pressure by bleeding off gas with the supply open. Therefore it is meaningful to deve lop emission factors for continuous bleed controllers on an emissions per unit time basis, but emissions from intermitten vent controllers are event based and therefore a function of event frequency which is going to vary depending on specific application parameters. This makes meaningful comparison very difficult unless you thoroughly analyze the field application and define the operating parameters and annual event frequency.

3. Did this paper capture the full range of technologies available to reduce emi ssions from pneumatic controllers and pneumatic pumps oil and gas facilities?

COMMENT: Even if there are other technologies out there

, the remote nature of the facilities will

limit more sophisticated and technological applications. It seems clear that c ompressed air and DC

electric motors need to be much more widely implemented, in conjunction with solar cells and properly sized battery banks for storage. Backup battery charging via wind generators should also be explored.

4. Please comment on the pros a nd cons of the different emission reduction technologies. Please discuss efficacy, cost and feasibility for both new and existing pneumatics.COMMENT: Maintenance standards should be the first requirements addressed. Given the

remoteness of the facilities there is a high probability that the pneumatic devices are operating at less than design efficiency. It is also likely tha t more stringent maintenance inspections and standards will lead to decisions to implement more efficien t reduction technologies. DC electric pumps powered by solar panels and battery storage banks for glycol recirculation is a very compelling alternative given the short pay

- back period. DC electric pumps for chemical injection are not as compelling, but if you are installing a DC electric system for other components then it is likely to be cost effective to siz e the system to include chemical injection electric pumps also. Replacing high bleed pneumatic controllers with low bleed pneumatic controllers seem s obvious, but the opportunities are likely to be very lim ited (see comment 5 below

– replacing high bleed continuous with intermitten) . Industry obviously does not want to throw saleable product away and therefore many of these opportunities have likely a lready been analyzed and acted upon.

5. Please comment on the prevalence of the different emission control technologies and the different types of pneumatics in the field. What particular activities require high bleed pneumatic controllers and how prevale nt are they in the field?

COMMENT: My discussions with industry environmental managers and engineers leave me with the impression that very little effort has been made implementing or enhancing emission control technologies , the exception being p erhaps with pneumatically controlled dump valves . There was a significant concern that the controller set point calibration needed more evaluation and that dump valve deposits may be preventing a complete seal such that after the liquids were drained methane

gas would continue bleeding past the valve. Dump valves, except for the largest, using high continuous bleed controllers would be better served and have less emissions when replaced with

intermitten vent controllers. High bleed pneumatic controllers are requir ed for dumping large volumes of liquid, large valves with significant inertia, and likely the examples cited on page 42, Applicability of the White Paper . D umping large liquid volumes actuated by a continuous high bleed pneumatic controller is likely to re sult in less emissions than using intermitten vent controllers that actuate more frequently. Emission curves need to be developed that clearly show the crossover in emission rates based on liquid volume dumped and type of pneumatic controller used.

6. What are the barriers to installing instrument air systems for converting natural gas

- driven pneumatic pumps and pneumatic controllers to air

- driven pumps and controllers?

COMMENT: If reliable electrical power is available there are no barriers that can not be reasonably

overcome

. The biggest concern was removing wa ter vapor, but the consensus is that the current technology reasonably addresses that problem. That of course begs the question what constitutes reliable electric power? A facility that has electri c power but currently classifies it as unreliable needs to upgrade its electrical service. If not through conventional utility service then it could be done by adding solar with battery storage backup . It should be mentioned that due to the huge market dem and for reliable DC battery storage systems and charging systems in the sailing industry that major advancements have been made in battery technology and charging systems, especially in instrumentation, charge monitoring and control. The Absorbed Glass Mat spiral cell marine battery is a good example of this tec hnology. These batteries allow cycling to as low as 50% without any of the negative effects of sulfation buildup. These systems are designed to survive in the harshest and most

corrosive environment there is: the marine salt water environment. This technology is directly applicable to the remote environment of the oil and gas industry. The cost of these systems willsignificantly decrease as production increases to cover the exp anded market created by the oil and gas industry.

7. Are there situations where it may be infeasible to use air driven pumps and controllers in place of natural gas

- driven pumps and controllers even where it is feasible to install an instrument air system?

COMMENT: No, instrument air driven pumps have all the capabilities of natu ral gas driven pumps.

T hese systems are designed with sufficient backup compression and auxiliary air storage such that reliable operation is assured

. Also these systems are desi gned such that emergency shutdown is the default position in the event of system failure. There may need to be some evaluation as to whether there is a potentially explosive environment, and in that case you would not want to use a medium

that contained ox ygen, but that does not appear to be the case in this application.

8. Did this paper correctly characterize the limitations of electric

- powered pneumatic controllers and pneumatic pumps? Are these electric devices applicable to a broader range of the oil a nd gas sector than this paper suggests?

COMMENT: DC electric pumps and controllers deriving their current from solar panels could be made significantly more reliable with a properly sized battery storage bank s

. If the facility has what

has been called “u nreliable AC electric power” this also can be made reliable with properly sized battery storage systems. Battery technology has vastly improved, especially in the area of marine batteries, and this is very applicable technology to remote installations. It seems probable that hybrid systems will emerge that use both compressed air and electric

- powered pneumatic controllers. These hybrid systems will likely also incorporate backup charging options for advanced battery storage

banks. Electric

- powered pneumatic controllers and pneumatic pumps are applicable to a broader range of the oil and gas sector because these devices are continuously evolving and the next generation will deliver stronger response for less current while maximizing energy savings.

9. Are there ongoing or planned studies that will substantially improve the current understanding of VOC and methane emissions from pneumatic controllers and pneumatic pumps and available techniques for increased product reco very and emissions reductions?

COMME NT: MuleShoe Engineering has prepared a paper on the subject that provides in depth knowledge on how these pneumatic devices work, how they are actuated, how they are properly defined and categorized, and where emissions reductions are most effectively ac hieved. A s is always the case once this technology is pushed forward industry and the front line regulating agency’s will partner to create workshops and tr aining programs to enhance understanding and affectively implement new regulation.