CAJ | 학술논문

为了了解在固定床气化炉中生物质的气化特性和炉内温度演变规律,该研究采用顶部点火上吸式(top-lit up draft,简称TLUD)固定床气化炉研究了农业废弃物的气化行为,重点考察了不同空气流量下炉内温度分布、燃气成分和热值的变化规律,探讨了生物质气化过程机理.结果表明,气化过程明显分为2个阶段,即挥发份的析出和焦炭的缓慢气化.整个气化过程中燃气的热值可稳定维持在3 MJ/m3以上,温度场的演变过程与波传递具有相似性,花生壳和稻壳的最佳空气当量比分别为0.31和0.35,且其燃气中焦油含量很低,分别为0.25、0.49 g/m3.该研究为TLUD固定床气化炉的设计和运行提供了有益的参考.
위료료해재고정상기화로중생물질적기화특성화로내온도연변규률,해연구채용정부점화상흡식(top-lit up draft,간칭TLUD)고정상기화로연구료농업폐기물적기화행위,중점고찰료불동공기류량하로내온도분포、연기성분화열치적변화규률,탐토료생물질기화과정궤리.결과표명,기화과정명현분위2개계단,즉휘발빈적석출화초탄적완만기화.정개기화과정중연기적열치가은정유지재3 MJ/m3이상,온도장적연변과정여파전체구유상사성,화생각화도각적최가공기당량비분별위0.31화0.35,차기연기중초유함량흔저,분별위0.25、0.49 g/m3.해연구위TLUD고정상기화로적설계화운행제공료유익적삼고.
The gasification behavior of agriculture waste was investigated using a Top-lit Up Draft (TLUD) fixed-bed gasifier system which consists of four subsystems (gasifier reaction system, temperature monitor system, tar sampling system, and gas measurement system), in an attempt to find out the influence of air flow on the gasifier’s temperature distribution, gas component, and heating value, and discuss the gasification mechanism of biomass. In the study, peanut shells and rice husks were chosen as experiment material. The reactor is made fromФ219 mm×6 mm stainless steel pipe with length of 800 mm. After the reactor filled up with sample materials (about 3.5 kg), a certain amount of air (range from 2.5 m3/h to 4.0 m3/h) was pumped in at the bottom, and the sample was lit at the top. The temperature was then tested by a temperature monitoring system, and the gas product was detected by a Gasboard-3100P-type multi-component portable infrared gas analyzer (Quartet Photoelectric Technology Co., Ltd. Wuhan, China), and the tar was collected by a tar sampling system. From the results of the investigation, the gasification process lasted about 100 min, and was divided into two stages. First, the main reaction was biomass drying, volatile releasing, and char gasification, and the main gas products were CO2, CO, H2, and CH4. About 50 min later, it went into the second stage, and the oxidization of solid char residue played a major role in the gasifier with a large amount of CO production. Throughout the whole reaction, the heating value of gas products was a minimum of 3 MJ/m3, and the evolution of the gasfier temperature profile was very similar with that of wave propagation. During the first stage of gasification, the maximum temperature of the gasifier was 730℃;when it switched into the second stage, the main reaction occurred at the bottom, and the max temperature would rise up to 1000℃. The airflow rate can be converted to the Air/Fuel equivalence ratio (ER), the most important aspect of gasifier operation. ER had great influence on biomass gasification property, and higher ER was favorable for the enhancing of gas yield, however, it had different effects on the releasing of flammable gas (CO and H2). The optimum gasfication condition was achieved when ER is 0.31 and 0.35 for peanut shell and rice husk, respectively, and the tar content of gas is very low (as low as 0.25g/m3 and 0.49g/m3, respectively). This study would be helpful to the design and operation of TLUD fixed-bed gasifiers.