# Presentation: 592014

## Lessons Learned 
from Natural Gas STAR

Offshore Technology Transfer Workshop

Shell, GCEAG, API, Rice University and
EPA’s Natural Gas STAR Program

June 8, 2004

**from Natural Gas STAR**
**Offshore Technology Transfer Workshop**
**Shell, GCEAG, API, Rice University and**
**EPA’s Natural Gas STAR Program**
**June 8, 2004**

**Partner Reported Offshore Methane Emissions Reduction Opportunities**

## Offshore PROs: Agenda

- Introduction to Partner Reported Opportunities (PROs) and Lessons Learned
- Selected PRO Overviews
- DI&M
- DI&M Industry Experience
- Discussion Questions

## Why Are Partner Reported Opportunities (PROs) Important?

- Partner Annual Reports document Program accomplishments
**BMPs: The consensus best practices**
**PROs: Partner Reported Opportunities**
- Simple vehicles for sharing successes and continuing Program’s future
**Lessons Learned: Expansion on the most advantageous BMPs and PROs**
**PRO Fact Sheets**
**Technology Transfer Workshops**
**Posted on www.epa.gov/gasstar**

## Why Are Partner Reported Opportunities (PROs) Important?

- Many production facilities have identified practical, cost-effective methane emissions reduction practices
- Production partners report saving 187 Bcf since 1990, 80% from PROs
- Vapor recovery units (VRUs) account for 30% of PRO emissions reductions

**Notes:**
Since 1990, Gas STAR Partners in all sectors (transmission/distribution; gathering/processing; and production) have saved approximately 340 Bcf of gas through the implementation of emissions reduction technologies and practices; nearly 84 percent of these reductions have been the result of PROs. Processing Partners are just beginning to identify cost effective methane savings: one Partner experimenting with DI&M has cost-effectively repaired 85% of leaks found by DI&M, saving 300 Mcf/day, worth $250,000 per year net savings.
Moreover, PROs are a central aspect of the Gas STAR Program, which seeks to foster peer-based technology transfer as a means of increasing program participation, and thus, emissions reductions.  To ensure continued program growth, one of EPA’s central goals is to assist Partners in identifying, implementing, and sharing PROs.  As will be discussed later in this presentation, the development and widespread dissemination of Lessons Learned studies -- which are based on the most promising PROs -- are one way in which this is accomplished. 

## Gas STAR PRO Fact Sheets

- 14 PROs apply to offshore operations
**From 38 PROs applicable to production**
**12 focused on operating practices**
**26 focused on technologies**
- PRO Fact Sheets are derived from Annual Reports 1994-2002
**Total 56 posted PROs at epa.gov/gasstar/pro/index.htm**

## Gas STAR Lessons Learned Studies

- 7 Lessons Learned  studies are applicable offshore
**From 10 applicable to production**
** ****2 focused on operating practices**
** ****8 focused on technology**
- All 16 Lessons Learned studies are on Gas STAR web site
**www.epa.gov/gasstar/lessons.htm**

## Lessons LearnedStudies for Offshore Operations

- Installing Vapor Recovery Units on Crude Oil Storage Tanks
- Optimize Glycol Circulation and Install Flash Tank Separators in Dehydrators
- Options for Reducing Methane Emissions from Pneumatic Devices in the Natural Gas Industry
- Convert Gas Pneumatic Controls to Instrument Air
- Reducing Emissions When Taking Compressors Off-Line
- Replacing Gas-Assisted Glycol Pumps with Electric Pumps
- Replacing Wet Seals with Dry Seals in Centrifugal Compressors

## More Opportunities Reported by Partners

- Replace Gas Starters with Air
- Replace Ignition – Reduce False Starts
- Install Electric Starters
- Rerouting of Glycol Skimmer Gas
- Convert Gas-driven Chemical Pumps to Instrument Air
- Pipe Glycol Dehydrator to Vapor Recovery Unit
- Convert Pneumatics to Mechanical Controls
- Install Electronic Flare Ignition Devices
- Install Ejector
- Inspect & Repair Compressor Station Blowdown Valves
- Install BASO® Valves
- Use Ultrasound to Identify Leaks
- Test and Repair Pressure Safety Valves
- Begin DI&M at Remote Facilities

## Examples of Technology Enabled PROs

- PROs enabled by instrument air system
**Replace Gas Starters with Instrument Air**
**Convert Gas-Driven Chemical Pumps to Instrument Air**
- PROs enabled by glycol dehydrators
**Reroute Glycol Skimmer Gas**
**Reroute Glycol Dehydrator to Vapor Recovery**
- PROs enabled by electric power
**Install Electric Starters**

## Replace Gas Starters with Air

- What is the Problem?
**Pressurized gas used to start engines is exhausted to atmosphere**
- Partner Solution
**Replace gas with compressed air**
- Methane Savings
**Based on one 3,000 HP reciprocating compressor with 10 start-ups per year**
- Applicability
**All natural gas pneumatic starter motors**
**Needs electric power to run air compressor**

| Methane Savings |  |
| --- | --- |
| 1,356 Mcf/yr |  |
|  |  |
| Project Economics |  |
| Project Cost | < $1,000 |
| Annual O&M Costs | $100 - $1,000
 |
| Payback | < 1 yr |

## Convert Gas-Driven Chemical Pumps to Instrument Air

- What is the Problem?
**Circulation pumps powered by pressurized natural gas vent methane**
- Partner Solution
**Replace natural gas with instrument air to power pumps **
- Methane Savings
**Based on one gas assisted glycol pump for a 10 MMcf/d gas dehydration unit**
- Applicability
**Can use surge capacity of existing instrument air system**
**Need electrical power if new instrument air compressor is installed**

| Methane Savings |  |
| --- | --- |
| 2,500 Mcf/yr |  |
|  |  |
| Project Economics |  |
| Project Cost | $1,000 - $10,000 |
| Annual O&M Costs | $100 - $1,000
 |
| Payback | < 1 yr |

## PROs for Glycol Dehydrators

- Dehydrators present an excellent opportunity to reduce emissions
- How much methane is emitted?
**A 20 MMcf/d dehydrator with no flash tank separator (FTS) and a gas pump can produce 7,600 Mcf/yr of losses**
- How can these losses be reduced?
**Lots of choices...install a flash tank separator, convert gas pump to electric pump and adjust glycol circulation rate****	**

**Notes:**
First consideration should be given to installing a flash tank separator but alternative steps would be to focus on disposition & recovery of vent streams as well as gas for pneumatic controllers and pump drives

## Reroute Glycol Skimmer Gas

| Methane Savings |  |
| --- | --- |
| 7,600 Mcf/yr |  |
|  |  |
| Project Economics |  |
| Project Cost | <$1,000 |
| Annual O&M Costs | $100 - $1,000 |
| Payback | < 1 yr |

- What is the Problem?
**Gas from condensate separator is vented to atmosphere**
- Partner Solution
**Reroute condensate separator gas for fuel use**
- Methane Savings
**Based on 20 MMcf/d dehydrator with no FTS, circulating 300 gph **
- Applicability
**All dehydrators with vent condensers**
**Small footprint**
**Condensate separator must operate at higher pressure than the gas destination**

## Pipe Glycol Dehydrator to Vapor Recovery

| Methane Savings |  |
| --- | --- |
| 3,300 Mcf/yr |  |
|  |  |
| Project Economics |  |
| Project Cost | $1,000 - $10,000 |
| Annual O&M Costs | > $1,000 |
| Payback | < 1 yr |

- What is the Problem?
**High pressure gas used to drive gas assist glycol pump is vented**
- Partner Solution
**Reroute gas from reboiler stack condenser vent to a VRU**
- Methane Savings
**Based on 10 MMcf/d gas dehydration unit with FTS, condenser and gas assist pump**
- Applicability
**Can use excess capacity of existing VRU**
**Small footprint**

## Install Electric Starters

- What is the Problem?
**Pressurized gas used to start engines is exhausted to atmosphere**
- Partner Solution
**Replacing starter expansion turbine with electric motor starter**
- Methane Savings
**Based on one engine starter, ten start-ups per year and methane leakage through gas shut-off valve**
- Applicability
**All sectors of gas industry**
**Access to electrical power supply**

| Methane Savings |  |
| --- | --- |
| 1,350 Mcf/yr |  |
|  |  |
| Project Economics |  |
| Project Cost | $1,000 - $10,000 |
| Annual O&M Costs | < $100 |
| Payback | 1- 3 yrs |

## Directed Inspection & Maintenance

## What is the Problem?

- Gas leaks are _invisible_, _unregulated_ and _go unnoticed_
- STAR Partners find that valves, connectors, compressor seals and open-ended lines (OELs) are major sources
**27 Bcf methane emitted per year by reciprocating compressors seals and OELs**
**Open ended lines contribute half these emissions**
- Facility fugitive methane emissions depend on operating practices, equipment age and maintenance

## How Can These Losses Be Reduced?

- Implementing a Directed Inspection and Maintenance (DI&M) Program

- Source: CLEARSTONE ENGINEERING LTD

## What is a DI&M Program?

- Voluntary program to identify and fix leaks that are cost-effective to repair
- Outside of mandatory LDAR
- Survey cost will pay out in the first year
- Provides valuable data on leakers

## How Do You Implement a DI&M Program?

**SCREEN and MEASURE leaks**** **

**Estimate repair cost, FIX to a Payback criteria**

**PLAN for future DI&M**

**Record savings/REPORT to Gas STAR**

**CONDUCT baseline survey**** **

**FIX on the spot leaks**

## One of the Newer Operating Practices

- Begin Directed Inspection and Maintenance at Remote Facilities
**SAVES... 362 Mcf/yr**
**PAYBACK ... < 1 yr**
- Enables several PROs
**Inspect and Repair Compressor Station Blowdown Valve**
**Use Ultrasound to Identify Leaks**
**Test and Repair Pressure Safety Valves**

- Bubble test on leaking valve
- Source: CLEARSTONE ENGINEERING LTD

## Screening and Measurement

## Natural Gas Losses by Source

**Combustion Equipment**

**9.9%**

**Amine Vents**

**0.5%**

**Flare Systems**

**24.4%**

**Non-leaking Components**

**0.1%**

**NRU Vents**

**0.3%**

**Storage Tanks**

**11.8%**

**Leaking Components**

**53.1%**

*Source: Clearstone Engineering, 2002*

**Natural Gas Losses by Source**

## Natural Gas Losses by Equipment Type

**Control Valves**

**4.0%**

**Open-Ended Lines**

**11.1%**

**Other Flow Meters**

**0.2%**

**Orifice Meters**

**0.1%**

**Pressure Relief Valves**

**3.5%**

**Valves**

**26.0%**

**Blowdowns**

**0.8%**

**Connectors**

**24.4%**

**Compressor Seals**

**23.4%**

**Crankcase Vents**

**4.2%**

**Pump Seals**

**1.9%**

**Pressure Regulators**

**0.4%**

*Source: Clearstone Engineering, 2002*

**Natural Gas Losses by Equipment Type**

## How Much Methane is Emitted?

## How Much Methane is Emitted?

## Cost-Effective Repairs

## DI&M - Partner Experience

**Partner A**: Leaking cylinder head was tightened, which reduced the methane emissions from almost 64,000 Mcf/yr to 3,300 Mcf/yr
**Repair required 9 man-hours of labor**
**Gas savings were approximately 60,700 Mcf/yr**
**Value of gas saved was  $182,100/year at $3/Mcf**
**Partner B**: One-inch pressure relief valve emitted almost 36,774 Mcf/yr
**Required five man-hours of labor and $125 of materials**
**Value of the gas saved was $110,300 at $3/Mcf**

## DI&M - Partner Experience

**Partner C**: Blowdown valve leaked almost 14,500 Mcf/yr
**Rather than replace the expensive valve, Partner spent just $720 on labor and materials to reduce the emissions to ~100 Mcf/yr **
**Value of gas saved was $43,200 at $3/Mcf**
**Partner D**: Tube fitting leaked 4,121 Mcf/yr
**Very quick repair requiring only five minutes reduced leak rate to 10 Mcf/yr**
**Value of the gas saved was $12,300 at $3/Mcf**

## Discussion Questions

- To what extent are you implementing these  opportunities?
- Can you suggest other opportunities?
- How could these opportunities be improved upon or altered for use in your operation?
- What are the barriers (technological, economic, lack of information, regulatory, focus, manpower, etc.) that are preventing you from implementing these practices?