New drilling techniques have increased availability and decreased costs of oil and gas. The decreased costs have caused an increase in drilling activity. The well sites have a large power demand that is typically met by diesel engines for the drilling derrick, fracking pumps, and electrical power. Dual fuel retrofit kits are being increasingly used at well sites to reduce operating costs and the amount of fuel trucked in to the site. Natural gas (NG) is cheaper compared to diesel and can be delivered to the site by the pipeline limiting the disturbance to surrounding communities due to diesel truck loads. The purpose of this work is to examine the performance of a typical dual fuel retrofit kit commissioned for field operation on a 6.8 L tier II diesel engine. After the baseline commissioning, the mechanisms limiting further substitution were clearly identified as engine knock similar to end gas auto-ignition in spark-ignited engines and governor instability. Two methods are examined for their ability to increase substitution limits by adjusting the start of injection timing (SOI) and the intake air manifold temperature. Retarding the SOI is able to delay the onset of knock at high loads and therefore increase the substitution level by around 4% at full load. At high loads, lowering the air manifold temperature is able to increase the substitution levels by around 10%. Preheating the intake air was able to increase low load substitution levels by 10% as well.

References

References
1.
EIA,
2017
, “
Petroleum and Other Liquids
,” U.S. Energy Information Administration, Washington, DC, accessed June 1, 2017, http://www.eia.gov/petroleum/gasdiesel/
2.
EIA,
2017
, “
Natural Gas
,” U.S. Energy Information Administration, Washington, DC, accessed June 1, 2017, http://www.eia.gov/dnav/ng/ng_pri_sum_dcu_nus_m.htm
3.
Nwafor
,
O. M. I.
,
2002
, “
Knock Characteristics of Dual-Fuel Combustion in Diesel Engines Using Natural Gas as a Primary Fuel
,”
Sadhana
,
27
(3), pp.
375
382
.
4.
Karim
,
G. A.
,
2003
, “
Combustion in Gas Fueled Compression: Ignition Engines of the Dual Fuel Type
,”
ASME J. Eng. Gas Turbines Power
, 125(3), pp.
827
836
.
5.
Abd Alla, G. H.
,
Soliman, H. A.
,
Badr, O. A.
, and
Abd Rabbo, M. F.
,
2000
, “
Effect of Pilot Fuel Quantity on the Performance of a Dual Fuel Engine
,”
Energy Convers. Manage.
, 41(6), pp.
559
572
.
6.
Abd Alla, G. H.
,
Soliman
,
H.
,
Badr
,
O.
, and
Abd Rabbo
,
M.
,
2002
, “
Effect of Injection Timing on the Performance of a Dual Fuel Engine
,”
Energy Convers. Manage.
, 43(2), pp.
269
277
.
7.
Hockett
,
A.
,
2016
, “
Development and Validation of a Reduced Chemical Kinetic Mechanism for Computational Fluid Dynamics Simulations of Natural Gas/Diesel Dual-Fuel Engines
,”
Energy Fuels
,
30
(3), pp.
2414
2427
.
8.
Konigsson
,
F.
,
2012
, “
Advancing the Limits of Dual Fuel Combustion
,” Royal Institute of Technology, Stockholm, Sweden.
9.
Carlucci
,
A. P.
,
2004
, “
Experimental Comparison of Different Strategies for Natural Gas Addition in a Common Rail Diesel Engine
,” Universitia del Salento, Lecce, Italy.
10.
Papagiannakis
,
R.
,
2003
, “
Experimental Investigation Concerning the Effect of Natural Gas Percentage on Performance and Emissions of a DI Dual Fuel Diesel Engine
,”
Appl. Therm. Eng.
, 23(3), pp.
353
365
.
11.
Papagiannakis
,
R. G.
, and
Hountalas
,
D. T.
,
2004
, “
Combustion and Exhaust Emission Characteristics of a Dual Fuel Compression Ignition Engine Operated With Pilot Diesel Fuel and Natural Gas
,”
Energy Convers. Manage.
,
45
(18–19), pp.
2971
2987
.
12.
Badr
,
O.
,
Karim
,
G. A.
, and
Liu
,
B.
,
1999
, “
An Examination of the Flame Spread Limits in a Dual Fuel Engine
,”
Appl. Therm. Eng.
,
19
(10), pp.
1071
1080
.
13.
Lounici
,
M. S.
,
Loubar
,
K.
,
Tarabet
,
L.
,
Balistrou
,
M.
,
Niculescu
,
D.-C.
, and
Tazerout
,
M.
,
2014
, “
Towards Improvement of Natural Gas-Diesel Dual Fuel Mode: An Experimental Investigation on Performance and Exhaust Emissions
,”
Energy
,
64
, pp.
200
211
.
14.
Cheng
,
W.
,
Harmin
,
D.
,
Heywood
,
J.
,
Hochgreb
,
S.
,
Min
,
K.
, and
Norris
,
M.
,
1993
, “
An Overview of Hydrocarbon Emissions Mechanisms in Spark Ignition Engines
,”
SAE
Paper No. 932708.
15.
Heywood
,
J. B.
,
1988
,
Internal Combustion Engine Fundamentals
,
McGraw-Hill
,
New York
.
16.
Hockett
,
A.
,
2015
, “
A Computational and Experimental Study on Combustion Processes in Natural Gas/Diesel Dual Fuel Engines
,”
Ph.D. thesis
, Colorado State University, Fort Collins, CO.https://dspace.library.colostate.edu/handle/10217/170357?show=full
17.
Mansor
,
W. N. W.
,
2014
, “
Dual Fuel Engine Combustion and Emissions: An Experimental Investigation Coupled With Computer Simulation
,”
Ph.D. thesis
, Colorado State University, Fort Collins, CO.https://dspace.library.colostate.edu/bitstream/handle/10217/88545/WanMansor_colostate_0053A_12810.pdf?sequence=1
18.
Olsen
,
D. B.
,
Neuner
,
B.
, and
Badrinarayanan
,
K.
,
2013
, “
Performance Characteristics of Oxidation Catalysts for Lean-Burn Natural Gas Engines
,”
Gas Machinery Conference
, Albuquerque, NM, Oct. 6–9.
You do not currently have access to this content.