1. A Theoretical Gas Quality Analysis of Natural Gas for Vehicles (NGV) in Thailand Yossapong Laoonual 1,2, Sumrerng Jugjai 2, Somchai Chanchaona 2 1 College of Integrated Science and Technology, Rajamangala University of Technology Lanna, 2 Combustion and Engine Research Laboratory (CERL), Department of Mechanical Engineering, King Mongkut’s University of Technology Thonburi Nuwong Chollacoop and Subongkoj Topaiboul 3 3 Energy Research Technology Group, National Metal and Materials Technology Center (MTEC)

2. Outline Introduction Natural gas quality in Thailand How to use the natural gas more efficient Summary

3. Natural Gas Quality Natural gas composition  Hydrocarbon  Inert gas  Sulfur Natural gas properties  Wobbe index  Methane number  A/F s

4. Typical Composition of Natural Gas Methane CH 4 (70- 95%) Rich gases C 2 H 6, C 3 H 8, C 4 + (0-20%) Inert gas N 2, CO 2, O 2 (0-8%) Sulfur H 2 S (0-5%) Rare gas He, Ne, Xe (trace)

5. Wobbe index (WI) WI quantifies the heat produced by the gas at a given time, after flowing through the fixed hole of gas injector. where WI= Wobbe index (J/m 3 ) H HV= high heating value (J/m 3 )  air = air density (kg/m 3 )  gas = gas density (kg/m 3 ) s = specific density

6. Methane Number (MN) MN = 1.624×(MON)-119.1 MON = -406.14+508.04(RHCR)- 173.55(RHCR) 2 +20.17(RHCR) 3 Methane number is the parameter used to quantify knocking tendency of an internal combustion engine using gas as the fuel.

7. Natural gas standard Composition / Properties SAE J1616 (1994) CARB (1992) NZS 5442 (1999) CPUC Rule 30 (2002) CARB (Draft) CH 4 - 88% (max) --- C2H6C2H6 - 6% (max) --- C3+C3+- 3% (max) --- C4+C4+----1.5% (max) C6+C6+- 0.2% (max) --- CO 2 3% (max) 0.1% (max) -3% (max)- CO 2 +N 2 +O 2 -1.5-4.5-4% (max) Sulfur 8-30 ppm 16 ppm (max) 50 mg/m 3 0.75 grain/100scf (max) 1 grain/100scf (max) Wobbe Index (MJ/m 3 ) 48.5- 52.9 -46-52±10% Not announce Methane number ---- Min 80 (statewide) Min 73 (regional) Heating values --- 36.1-42.8 MJ/m 3 (max) - Specific density -- 0.8 (max) --

8. High N 2 => Nitric Oxide Formation N 2 2N N+ O 2 NO+O N+ OH NO+H High CO 2 => FeCO 3 Corrosion in NG cylinder Natural gas composition

9. Natural Gas Sources in Thailand Northeast North West East South

10. Natural gas composition Compo sitio n East (2006- 2009) West (2007) Khano m South Namph ong Northe ast Lankrab u North CH 4 74.1- 77.5% 72.4%62.6- 69.6 % 95.5%84.7- 85.4% C2H6C2H6 5.4-6.0%3.5%8.3- 9.0% 0.6%11.2- 11.4% C3C3 1.5-2.4%1.06%0.72- 5.1% 0.07%1.34- 1.81% C4C4 0.59-0.9%0.47%0.02- 0.38 % 0.06%0.24- 0.48% C5C5 0.1-0.15%0.1%0.05- 0.19 % -0.07- 0.14% C6+C6+0.02- 0.04% 0.07%0.01- 0.3% 0.02%0.03- 0.065 % N2N2 2.0-2.2%16%0.7- 0.76 % 1.8%0.5-0.6% CO 2 12.7- 14.4% 6.2- 6.4% 20.3- 21.9 % 2.0%1% Sulfur<16 ppm10-19 ppm <16 ppm <500 ppm -

11. Natural gas properties PropertiesEast (2006 - 200 9) West (2007) Khano m South Namph ong Northe ast Lankrab u North High heating value (MJ/m 3 ) * 35.75- 38.9 6 33.2331.59- 40.52 38.6443.39- 44.77 Wobbe Index (MJ/m 3 )* 42.18- 43.7 3 39.1- 39.2 34.6- 42.14 50.4454.5-55.2 Methane Number 76-818664-8010575-78 A/F s 11.8- 11.9 5 11.110.0- 10.6 15.815.816.4 *Calculated from DIN 51857-1997

12. Wobbe index in Thailand

13. Wobbe Index around the world

14. Natural gas variation compared to east Compon ents & Gas quality Variation (other sources- east)/east East (200 7) We st (20 07) Kha nom (200 7) Nam Phong (2007 ) Lankr abu (2007 ) CH 4 -- 4% -13%26%12% C2H6C2H6 -- 39 % 52%-89%98% CO 2 -- 54 % 56%-85%-93% N2N2 -662 % -65%-14%-74% Wobbe Index -- 9% 17%28% Methane Number -9%-8%34%-3% A/F S -- 7% -14%33%38%

15. How to use the natural gas more efficient Two ways to propose solutions Suitable gas quality  Improve gas quality e.g. install gas separation plant  Issuing Thai natural gas standard Suitable engine technology  Adaptive electronic control unit (ECU) with wideband oxygen sensor  Wobbe index sensor or gas composition sensor

16. Summary Significant gas quality variation in Thailand. Required gas quality standard in Thailand. Required qualitative engine performance and emission test from various gas sources. Required proper engine technology.

17. Thank you & Any Questions ?