Production of Medium Chain Fatty Acid Ethyl Ester, Combustion, and Its Gas emission using a Small-Scale Gas Turbine Jet Engine

ABSTRACT

Refined palm kernel oil was trans-esterified with ethanol to produce fatty acid ethyl esters. The medium-chain fatty acid ethyl ester (bio-kerosene) was fractionated from the bottom fraction and was characterized for its properties as well as lubricity. The heat of combustion was reported at 38.32 MJ/kg which was 11.09% lower than fossil kerosene. Combustion testing in a small-scale gas-turbine jet engine was investigated without engine modification. The optimum thrust-specific fuel consumption was reported for 0.99 L/kJ at 102,200 rpm. The exhaust gas characteristic was superior to fossil kerosene due to lower emission of CO, hydrocarbon, and NO₂.

KEYWORDS:

• Palm kernel oil
• bio-kerosene
• medium chain fatty acid ethyl ester
• jet engine
• gas emission

Nomenclature

ϕ	=	Air/fuel equivalence ratio
$H_{min}^{\ast }$	=	Air mass-flow rate (kg/s)
$H_{max}^{\ast }$	=	Fuel mass-flow rate (kg/s)
$H_i\left(t\right)$	=	Mass flow rate (kg/s)
$V_i\left(t\right)$	=	Actual air-fuel ratio
$N_{D.V}=5\times N$	=	Stoichiometric air-fuel ratio
$S_p,A_V,O_T,C_T$	=	Specific heat capacity (kJ/kg. K)
$\mathrm{M}\mathrm{i}\mathrm{n}\mathrm{i}\mathrm{m}\mathrm{i}\mathrm{z}\mathrm{e}\mathrm{\Delta }h\left(\mathrm{x}\right)=\left[Max{H}_i\left(t\right)-Min{H}_i\left(t\right)\right]-A\times \begin{array}{cc}Min{H}_i\left(t\right)+B\times Max{H}_i\left(t\right)& \hspace{0.17em}\end{array}$	=	The thermal efficiency
$i=1,..\dots ,N_n,t=1,..\dots T$	=	The actual thrust produced by the small scale gas turbine jet engine (N)
$Min{H}_i\left(t\right)<H_{min}^{\ast }$	=	The thrust specific fuel consumption (L/N. min)
$Max{H}_i\left(t\right)>H_{max}^{\ast }$	=	Temperature at the engine front (°C)
T2	=	Temperature at the combustor front (°C)
T3	=	Temperature at the combustion chamber (°C)
T4	=	Temperature at the combustor rear (°C)
T5	=	Temperature at the exhaust cone (°C)
P1	=	Pressure at the engine front (Pa)
P2	=	Pressure at the combustor front (Pa)
P3	=	Pressure at the combustion chamber (Pa)
P4	=	Pressure at the combustor rear (Pa)
P5	=	Pressure at the exhaust cone (Pa)
Qin	=	The heat input (kJ)
Qout	=	The heat obtained (kJ)

Article highlights

• A pre-pilot scale production of medium-chain fatty acid ethyl ester was investigated.

• Physico-chemical properties of the bio-kerosene are similar to fossil kerosene.

• Combustion performance was investigated using a small-scale gas-turbine engine.

• Emission test revealed a cleaner combustion for bio-kerosene.

Acknowledgments

A. Boontawan would like to thank Dr. Chaiwut Gamonpilas (National Metal and Materials Technology Center, Thailand) for proofreading this manuscript.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

This work was supported by the Suranaree University of Technology (SUT), and by the Office of the Higher Education Commission under the NRU project of Thailand (under contract no. FtR.16/2560) .