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. The 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 controller 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 different ranges 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 going to give meaningful 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 develop 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 emissions 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 compressed 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 and 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 that more stringent maintenance inspections and standards will 

lead to decisions to implement more efficient 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 size

the system to include chemical injection electric pumps also. Replacing high bleed pneumatic 

controllers with low bleed pneumatic controllers seems obvious, but the opportunities are likely to be 

very limited (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 already 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 prevalent 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 perhaps 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 required for dumping large 

volumes of liquid, large valves with significant inertia, and likely the examples cited on page 42, 

Applicability of the White Paper. Dumping large liquid volumes actuated by a continuous high bleed 

pneumatic controller is likely to result 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 water 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 electric 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 demand 

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 technology. 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 will 
significantly decrease as production increases to cover the expanded 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 natural gas driven pumps. 

These systems are designed with sufficient backup compression and auxiliary air storage such that 

reliable operation is assured. Also these systems are designed 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 oxygen, 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 and 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 banks. If the facility has what 

has been called “unreliable 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 recovery and emissions reductions? 

COMMENT: 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 achieved. As is always 

the case once this technology is pushed forward industry and the front line regulating agency’s will 

partner to create workshops and training programs to enhance understanding and affectively 

implement new regulation.