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The combustion of polyolefins in inert and catalytic fluidised beds
Journal of Cleaner Production ( IF 11.1 ) Pub Date : 2019-07-17 , DOI: 10.1016/j.jclepro.2019.117663
Witold Żukowski , Gabriela Berkowicz

The thermal degradation of polyethylene and polypropylene were performed in three types of fluidised bed consisting of sand, inert hollow microspheres (cenospheres) with a density of <1 g/cm3, or the same cenospheres covered with Fe2O3. For the first time, the cenospheres were proposed as material of fluidised bed that allowed the immersion of polymeric material. With regard to combustion, this is organised inside a fluidised bed reactor consisting of sand as the bed material; the combustion of polyolefins occurs in the freeboard with considerable soot formation. Based on acoustic and video analyses, it was proven that the combustion of polyolefins in the cenospheric fluidised bed reactor occurs inside the fluidised bed. It takes the form of explosions in the bubbles or takes place in the emulsion phase. In the cenospheric fluidised bed, a 97–99% yield of polyolefin conversion can be achieved at 800 °C. Catalytic combustion in the fluidised bed reactor was also proposed, for this, catalytic bed material was prepared by chemical Fe2O3 deposition on the cenospheres. As precursor Fe(CO)5 was used.

As a consequence of changing the non-catalytic fluidised bed into a catalytic bed, conversion to CO2 increased from 57-59% to 80–85% at temperatures as low as 500 °C. Furthermore, at 800oC–900 °C, the CO2 yield increased from 97-99% to 98–99%, these small differences caused the CO concentration in the catalytic process to be 2–4 times lower than in the case of the process conducted in the inert fluidised bed. The use of a catalytic bed led to the complete elimination of explosions, thus it is safer and also leads to lower NOX emissions. Based on experimental data, NOx concentration did not exceed 6 mg in a cubic metre of dry exhaust gases containing 11%vol.O2 at all tested temperatures (500–900 °C).



中文翻译:

惰性和催化流化床中聚烯烃的燃烧

聚乙烯和聚丙烯的热降解在三种类型的流化床中进行,该流化床由沙子,密度小于1 g / cm 3的惰性空心微球(空心球)或覆盖有Fe 2 O 3的相同空心球组成。首次提出将空心球作为流化床的材料,以使其能够浸入聚合物材料中。关于燃烧,将其组织在流化床反应器内部,该反应器由沙子作为床层材料组成。聚烯烃在干舷内燃烧,形成大量烟灰。基于声学和视频分析,已证明,在平流层流化床反应器中聚烯烃的燃烧发生在流化床内部。它采取气泡爆炸的形式或发生在乳液相中。在平流层流化床中,在800°C时可实现97-99%的聚烯烃转化率。还提出了在流化床反应器中的催化燃烧,为此,通过化学Fe 2 O制备催化床材料。3在小行星上的沉积。使用Fe(CO)5作为前体。

将非催化流化床改为催化床的结果是,在低至500°C的温度下,CO 2的转化率从57-59%增加到80-85%。此外,在800 o C–900°C的温度下,CO 2的产率从97-99%增加到98-99%,这些微小的差异使催化过程中的CO浓度降低了2–4倍。该过程在惰性流化床中进行。使用催化床可以完全消除爆炸,因此更安全,还可以降低NO X排放量。根据实验数据,在一立方米的干废气(体积分数为11%)中,NOx浓度不超过6 mg Ø 2 在所有测试温度下(500–900°C)。

更新日期:2019-07-17
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