|This deliverable forms part of Deliverable 2.2 in Work Package 2 and provides information on the gas engine and turbine rig scale testing. The tests of operating a reciprocating internal combustion spark ignition engine conducted for the ETI Energy from Waste project show that engine operation on gases comprised of varying proportions of hydrogen (H2) and carbon monoxide (CO) with adiabatic flame temperatures bounding that of methane (?Natural Gas?, CH4) is feasible. Using an engine configuration (compression ratio) designed for natural gas applications in conjunction with an optimised spark timing for the gas flame speed appears to indicate a thermal efficiency of 35% is achievable; it was beyond the scope of this work to examine whether the compression ratio could be optimised further, although this is likely to be highly fuel composition dependant, and hence difficult to define for ?product gas? as a whole (due to wide range of compositions and properties this encompasses).The pictures and analysis of engine components post testing do show quite high levels of deposit formation, which appear to indicate increased service requirements when operating on these gases, although an accurate assessment of this impact would require longer term durability testing, which was beyond the scope of the present work.
Similarly, the presence of tars, particulates, trace metals and other chemical contaminants (e.g. chlorine, sulphur etc.), as commonly found in product gases derived from waste material feedstocks, would be expected to have a highly detrimental effect on engine performance and longevity. However, these test results have achieved the project ambitions by proving the ability of using product-type gases in internal combustion machines, and deriving sufficient experimental data to derive a simple engine model liking the input gas composition to the power generated, as developed in Work Package 3 of this project.