Emisja tlenku azotu NOx ze spalania biomasy wierzbowej

Celem pracy była ocena emisji NOx ze spalania biomasy wierzbowej kilku klonów wierzby krzewiastej (Salix viminalis) pozyskanej w drugim, trzecim i czwartym roku uprawy w rejonie Koszalina, na glebie lekkiej, na zróżnicowanym nawożeniu organicznym i mineralnym.

In the study the influence of combustion of shrubby willow shoots was evaluated in laboratory conditions upon the content of the nitrogen oxide NOx in combustion gases. Analyses covered biomass of nine willow's clones cultivated four years in light soil using compost from municipal sewage sludge and diverse doses of fertilizer Hydrofoska 16. Samples of biomass were taken in two terms (directly after mowing during winter and at the turn of May and June). The combustion of samples of willow biomass from the willow's crop after the harvest in the first and second term in years 2008÷2010 was carried out in temperatures: 300°C, 600°C, 900°C and 1200°C. During combustion the intensity of air flow amounted to 8.0 dm3 ź min-1. Formation of nitrogen oxide NOx during combustion of willow biomass was mostly influenced by temperatures of combustion (73.4%), less influenced by age of acquired willow shoots (10.6%), and joint action of temperature of combustion and age of the willow shoots (8.0%), and relatively little influenced but essential, by day of biomass harvesting (0.3%), fertilizer combinations (0.2%) and the willow clones (0.1%). The differences among extreme levels of factors under investigation concerning content of nitrogen oxide NOx in combustion gases in order of diminishing effects were ranked as follows: temperature of biomass combustion - 212.7 mg/m? NOx, age of the willow's shoots - 71.6 mg/m? NOx, fertilizer combina-tions - 12.0 mg/m? NOx, date of biomass sampling - 8.7 mg/m? NOx and the willow's clones - 8.5 mg/m? NOx. The smallest quantities of nitrogen oxide NOx formed in the process of combustion of biomass developed in temperature 300°C, and the highest in temperature 1200°C. Increase of combustion temperature from 300°C to 1200°C resulted in increase of the content of nitrogen oxide NOx in combustion gases. The smallest quantities of nitrogen oxide NOx produced during combustion of the willow biomass were obtained in fourth year of cultivation, and higher from cultivations in third and second year. The highest quantities of nitrogen oxide NOx produced during combustion of the biomass were generated from "d" objects, where the highest doses of compost and the fertilizer Hydrofoska 16 were applied. On the contrary, the smallest quantities of nitrogen oxide NOx were produced during combustion of biomass from "a" objects, where compost and fertilizer Hydrofoską 16 were not applied. Use of intensive organic and mineral fertilization (object "d") caused essential stronger air pollution by nitrogen oxide NOx than combustion of biomass originating from objects of lower mineral fertilization (object "c"). Higher quantities of nitrogen oxide NOx were produced during combustion of willow biomass from the first term of sampling biomass (February 2008 and 2009 and November 2009) than from the second term of sampling (at the turn of May and June). The highest quantities of the nitrogen oxide NOx were produced during combustion of willow biomass clone 1052 (127.8 mg/m?), and the smallest during combustion of clone 1033 (119.3 mg/m?). Creation of the nitrogen oxides NOx was influenced by double interactions also: fertilizer combinations with temperatures of combustion, fertilizer combinations with age of shoots, temperatures of combustion with term of sampling, temperatures of combustion with age of shoots and date of sampling with age of shoots, and also threefold interaction of temperatures of combustion with term of sampling and age of shoots and fourfold interaction of fertilizer combinations with temperatures of combustion, term of sampling and the age of shoots. Total interactions were responsible for 15.4% of content of nitrogen oxide NOx in combustion gases.