Emissions and Soot in Partially Premixed Combustion - Novel Combustion Concepts for Sustainable Energy Development - page 424

Emissions and Soot in Partially Premixed
Combustion

Surbhi Kohli and Abhijit Kushari

Abstract Practical combustion systems typically undergo non-premixed mode of
combustion, in which the fuel is injected directly into the combustion chamber,
which already has compressed air. The emissions tend to be high in this diffusion
mode of combustion as compared to premixing mode. But a switch to premixing is
not desirable for practical systems as the premixed air-fuel mixtures are more
accident-prone. Partial premixing implies that the fl flame is only partially premixed

and in parts, it is also a diffusion flame. This refers to the condition when a small

amount of air or oxygen is mixed with the fuel (rich mixture), before it enters the
reaction zone and then further at the reaction zone, more quantities of oxidizer are
added, so as to make the overall mixture lean and to complete the combustion.
Experimental study of partially premixed, co-

fl

flames are reported in
this chapter, which show substantial improvement in emission and soot charac-
teristics in comparison to a pure diffusion

fl ow, LPG-air fl

flame for a swirl stabilized combustor
when the premixing equivalent ratio was kept between 1.5 to 2.0.

fl

Keywords Partially premixed combustion (PPC) Liquid petroleum gas (LPG)

Equivalence ratio Diffusion fl ame Health hazards CO and NO emissions

1 Introduction

Humans have unscrupulously used available resources on earth and have extracted
the maximum out of them in order to ease their life on this planet. But in doing so,
they have also disturbed the ecological balance of nature. Thus, with the excessive
exploitation of resources; the entire

flora and fauna, including mankind itself is in
danger. Omens for this are already being seen

fl

— the erratic climatic patterns all over