Agro-pellets for domestic heating boilers: standard laboratory and real life performance.

One multi-fuel domestic pellet boiler (40kW) was tested under standard laboratory conditionswhile fired with eight different biomass pellets and two boilers (35kW) were tested in real lifeconditions while fired with DINplus certified wood pellets. The agro-pellets include applepomace (Malus domestica), reed canary grass (Phalaris arundinacea), pectin waste from citrusshells (Citrus reticulata), sunflower husk (Helianthus annuus), peat, wood and two types ofwheat straw pellets (Triticum aestivum). The measurements comprised of carbon monoxide (CO),nitrogen oxides (NOx), sulphur oxides (SOx), particle mass concentration (by DINplus samplingmethods) and combustion efficiency.Under standard laboratory conditions, wood pellets yielded the highest combustion efficiency(92.4%) followed by apple pellets (91.3%). The CO and dust emissions were the highest withpeat and sunflower husk pellet, respectively. Straw pellets emitted the highest NOx and SOx. Foragro-pellets, statistical differences in ash contents were significant. High ash contents and lowash melting temperature made straw pellets less suitable for this type of boilers. Reed canarygrass, citrus pectin and apple pellets have advantage over others with reasonable less ash contentsand less emissions.In the real life conditions, the boilers had around 90 percent combustion efficiencies. Comparisonwith the standard laboratory performance showed that the NOx emission was higher in real lifecondition than standard laboratory conditions; however, lowed CO and particle emissions werereported in real life conditions. In the real life condition, dust emissions were 5.0 and 5.8 mgNm-3with RL-1 and RL-2 boilers, respectively. Examination of the dust using FE-SEM revealed thatmost of the dust particle had a tendency to form small clusters of sub-micron size rangingbetween 300nanometer to 1.2micrometer.

Jaar van publicatie:2012

Trefwoorden:multi-fuel boiler; agro-pellets;, real life performance,, standard laboratory performance, dust