Waste Gypsum Board and Ash-Related Problems during Combustion of Biomass. 1. Fluidized Bed

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• 作者：Patrycja Piotrowska ; Anders Rebbling ; Daniel Lindberg ; Rainer Backman ; Marcus 脰hman ; Dan Bostr枚m
• 刊名：Energy & Fuels
• 出版年：2015
• 出版时间：February 19, 2015
• 年：2015
• 卷：29
• 期：2
• 页码：877-893
• 全文大小：1436K
• ISSN：1520-5029

文摘

This paper is the first in a series of two describing the use of waste gypsum boards as an additive during combustion of biomass. This paper focuses on experiments performed in a bench-scale bubbling fluidized-bed reactor (5 kW). Three biomass fuels were used, i.e., wheat straw (WS), reed canary grass (RC), and spruce bark (SB), with and without addition of shredded waste gypsum board (SWGB). The objective of this work was to determine the effect of SWGB addition on biomass ash transformation reactions during fluidized bed combustion. The combustion was carried out in a bed of quartz sand at 800 or 700 掳C for 8 h. After the combustion stage, a controlled fluidized鈥揵ed agglomeration test was carried out to determine the defluidization temperature. During combustion experiments, outlet gas composition was continuously measured by means of Fourier transform infrared spectroscopy. At the same place in the flue gas channel, particulate matter was collected with a 13-stage Dekati low-pressure impactor. Bottom and cyclone fly ash samples were collected after the combustion tests. In addition, during the combustion tests a 6-h deposit sample was collected with an air-cooled (430 掳C) probe. All ash samples were analyzed by means of scanning electron microscopy combined with energy dispersive X-ray spectrometry for elemental composition and with X-ray powder diffraction for the detection of crystalline phases. Decomposition of CaSO₄ originating from SWGB was mainly observed during combustion of reed canary grass at 800 掳C. The decomposition was observed as doubled SO₂ emissions. No significant increase of SO₂ during combustion of SB and WS was observed. However, the interaction of SWGB particles with WS and SB ash forming matter, mainly potassium containing compounds, led to the formation of K₂Ca₂(SO₄)₃.