Acetylene as dual fuel with diesel
30 April 2011
Researchers from the College of Engineering at Anna University (India) are proposing the use of acetylene as a dual fuel with diesel in compression ignition engines. Dual-fuel operation with acetylene induction coupled with cooled EGR resulted in lowered NOx emissions and improved part load performance.
| Acetylene | Hydrogen | Diesel | |
|---|---|---|---|
| Formula | C2H2 | H2 | C8–C20 |
| Density kg/m3 | 1.092 | 0.08 | 840 |
| Auto ignition °C | 305 | 572 | 257 |
| Stoichiometric air fuel ratio | 13.2 | 34.3 | 14.5 |
| Lower calorific value (kJ/kg) | 48,225 | 120,000 | 42,500 |
| Lower heating value of stoich. mix (kJ/kg) | 3396 | 3399 | 2930 |
| Source: Lakshmanan and G. Nagarajan (2009) | |||
Acetylene (C2H2) is the simplest alkyne, featuring a triple carbon bond between the two carbon atoms. This bond stores substantial energy that can be released as heat during combustion; combustion with oxygen achieves a flame temperature of 5,580° F (3,087° C), releasing 1,470 BTUs per cubic foot.
Lakshmanan and Nagarajan used timed manifold injection (TMI) of the gaseous fuel, controlled electronically to precisely monitor the induction of fuel to overcome the preignition problem in the intake.
In a study published in the journal Energy, they injected acetylene in the intake manifold in a single cylinder diesel engine, with a gas flow rate of 240 g/h, start of injection time of 10° aTDC and 90° CA (9.9 ms) duration, operating in dual fuel mode. In order to decrease the NOx emissions from acetylene–diesel engine, cooled EGR was employed.
In the study, they achieved 21% maximum diesel replacement, and suggest that acetylene could be commercialized as a fuel for diesel engines in the future.
Resources
T. Lakshmanan and G. Nagarajan (2011) Study on using acetylene in dual fuel mode with exhaust gas recirculation. Energy doi: 0.1016/j.energy.2011.03.061
T. Lakshmanan and G. Nagarajan (2009) Performance and Emission of Acetylene-Aspirated Diesel Engine. Jordan Journal of Mechanical and Industrial Engineering. Volume 3, Number 2.
Well, I guess in India the explosive potential of acetylene is no big deal. Here in the U.S., the stuff is even harder to come by because commercial production of it is heavily restricted and controlled. There's a reason they stopped using acetylene bottles to power headlamps...
Posted by: Aaron Turpen | 30 April 2011 at 08:10 PM
Acetylene isn't stored as compressed gas; it's held in solution in something else, IIRC. If it's significantly soluble in diesel fuel, it could be piped in through the regular fuel system. It wouldn't surprise me if it provides a major enhancement of the cetane rating, too.
Posted by: Engineer-Poet | 02 May 2011 at 12:27 PM
Acetylene dissolves in hydrocarbons, which IIRC is how it's stored (in acetone?) for welding use.
Using dissolved acetylene in diesel fuel or other oil might be a way to both co-fuel with it and use it as a cetane enhancer without modifying the fuel system.
Posted by: Engineer-Poet | 03 May 2011 at 01:22 PM
acetylene as an alternate fuel for si engines....
www.hindu.com/2005/10/01/stories/2005100103060300.htm
Posted by: IP-cloud | 24 February 2013 at 02:05 PM