Improvement of Municipal Solid Waste Syngas Premixed Flame with Cellular Structure on a Flat Burner

This research was conducted to study the flame instability of syngas derived from raw
municipal solid waste (MSW) and its potential as a natural gas (NG) replacement in power generation.
MSW syngas is a mixture of various components such as methane (CH4), nitrogen (N2), oxygen (O2),
and hydrogen (H2), whereas NG is mainly composed of CH4 (>70%) and CO2 (>10%). The flame
characteristics of these two gases are quite different thus a direct replacement of NG with MSW syngas
is impossible. Improvements to MSW syngas combustion are needed through the augmentation of the
gas with CH4 and H2 active additives at various ratios so that its flame characteristics are comparable
to those of NG. A typical MSW syngas composed of 16.2% methane (CH4), 13.5% hydrogen (H2),
69.1% nitrogen (N2), and 0.6% oxygen (O2) (by vol.) is available in Thailand with great potential for
use as an NG replacement. In this study, this gas is used as a representative fuel for improvement and
is referred to as simulated Syngas 1. Its premixed flame was studied using a McKenna flat burner
to understand its flame instability. Various percentages of CH4 and H2 were added to Syngas 1. Its
flame characteristics were measured and compared to those of NG. These characteristics included the
cellular flame, cell size, flat flame, flammability limit, and flame temperature. The results showed
that the flame instability of Syngas 1 was significantly suppressed by adding minimal amounts of
CH4 and H2. The new composition of Syngas 1 consisted of 19.3% methane (CH4), 19.0% hydrogen
(H2), 61.2% nitrogen (N2), and 0.5% oxygen (O2) (by vol.). It yielded flame characteristics that were
comparable to those of an NG flame. This study shows that MSW syngas can potentially replace NG
in power generation.