CAJ | 학술논문

互花米草是一种高 Na、K 含量的盐生植物，直接燃烧存在结渣与沉积腐蚀问题，而与煤炭共热解可以有效发挥其高碱金属含量的特点。该文采用热重-傅立叶红外联用分析法（thermogravimetric analysis coupled with Fourier transform infrared spectroscopy，TG-FTIR）研究了互花米草与褐煤在质量比（S∶L）分别为1∶4、2∶3、3∶2和4∶1条件下的共热解特性。试验所用互花米草的Na、K质量分数分别为16064.3和6175.7 mg/kg，挥发分质量分数为75.40%，褐煤的挥发分质量分数为33.92%。TG分析表明，4种混合原料共热解均产生了协同效应，且主要表现为385～510℃温度区间内互花米草对褐煤热解的促进作用，在该温度区间内共热解反应活化能随互花米草比例的增加呈下降趋势，由褐煤单独热解时的53.62 kJ/mol最低降到S∶L为4∶1时的13.34 kJ/mol，同时共热解比褐煤单独热解反应速率常数升高幅度达到1～2个数量级。热解气体的FTIR分析表明，共热解可以提高热解气体的质量，与单独热解相比共热解可以促进CH4和CO气体的产生。从提高热解气体质量角度分析，4种混合样品中S∶L为3∶2和4∶1的协同效应更为明显。研究表明互花米草可以用作煤炭热解的可弃催化剂，拓宽了互花米草的能源化利用途径。
호화미초시일충고 Na、K 함량적염생식물，직접연소존재결사여침적부식문제，이여매탄공열해가이유효발휘기고감금속함량적특점。해문채용열중-부립협홍외련용분석법（thermogravimetric analysis coupled with Fourier transform infrared spectroscopy，TG-FTIR）연구료호화미초여갈매재질량비（S∶L）분별위1∶4、2∶3、3∶2화4∶1조건하적공열해특성。시험소용호화미초적Na、K질량분수분별위16064.3화6175.7 mg/kg，휘발분질량분수위75.40%，갈매적휘발분질량분수위33.92%。TG분석표명，4충혼합원료공열해균산생료협동효응，차주요표현위385～510℃온도구간내호화미초대갈매열해적촉진작용，재해온도구간내공열해반응활화능수호화미초비례적증가정하강추세，유갈매단독열해시적53.62 kJ/mol최저강도S∶L위4∶1시적13.34 kJ/mol，동시공열해비갈매단독열해반응속솔상수승고폭도체도1～2개수량급。열해기체적FTIR분석표명，공열해가이제고열해기체적질량，여단독열해상비공열해가이촉진CH4화CO기체적산생。종제고열해기체질량각도분석，4충혼합양품중S∶L위3∶2화4∶1적협동효응경위명현。연구표명호화미초가이용작매탄열해적가기최화제，탁관료호화미초적능원화이용도경。
Smooth cordgrass (Spartina alterniflora), a saltmarsh plant, has spread in intertidal flats of many regions of China since it was introduced from the USA in 1979. The application of S. alternilfora in energy has gained more attention due to its high production. However, the direct combustion of S. alternilfora was hindered due to its high potassium (K) and sodium (Na) contents. Co-pyrolysis of biomass and coal, a subject of much study in an effort to reduce greenhouse gases emission, was reported to be able to produce a synergetic effect mainly due to the catalytic function of alkali metals in biomass. S. alterniflora, rich in Na and K which are 22 683 mg/kg and 8 063 mg/kg, respectively, has great bioenergy potential as a co-pyrolysis material of coal. In order to to verify the interaction of S. alterniflora and lignite during pyrolysis, experiments were carried out with pure S. alterniflora, pure lignite, and their blends with mass ratio (S. alterniflora to lignite, S:L) of 1:4, 2:3, 3:2, and 4:1 by thermogravimetry coupled with a Fourier transform infrared spectroscopy (TG-FTIR). S. alternilfora used in the experiments was collected from Dafeng County of Jiangsu Province, China in October 2012. Lignite was from Shanxi Province, China. Na, K, volatile, H/C, O/C, and heating value of S. alterniflora were 16 064.3 mg/kg, 6 175.7 mg/kg, 75.40%, 0.12, 0.80, and 19.08 MJ/kg, respectively. Volatile content, H/C, O/C, and heating value of lignite were 33.92%, 0.07, 0.23, and 20.47 MJ/kg, respectively. TG tests were done under an N2 flow rate of 25 mL/min and at a heating rate of 10℃/min from 30℃ to 900℃. Infrared scanning resolution was set to 4cm-1, and scanning scope varied from 4 000 cm-1 to 500 cm-1. According to TG and DTG analysis, the process of co-pyrolysis can be divided into two stages at 385℃. The pyrolysis of S. alterniflora took place mainly in the first stage of 250℃ to 385℃. The pyrolysis of lignite and fixed carbon in S. alterniflora occurred in the second stage. TG analysis results showed that the activation energy (Ea) for co-pyrolysis decreased with the increase of S. alterniflora in the blends in the range of 385℃to 510℃, especially for the blend with S:L of 4:1, whose Ea decreased to 13.34 kJ/mol compared to the 53.62 kJ/mol of pure lignite pyrolysis. At the same time, the reaction rate constant k for co-pyrolysis increased by one to two orders of magnitude compared to pyrolysis of lignite alone, although the frequency factor A of co-pyrolysis decreased. After heating the temperature over 385℃, obvious differences occurred between the calculated values and the test values of TG and DTG. This situation continued to 700℃. FTIR analysis of pyrolysis gas showed that co-pyrolysis improved the quality of pyrolysis gas by enhancing the yields of CO and CH4, especially for two blend samples with higher S. alterniflora content in which there were significant CO releasing peaks around 400℃. On the contrary, for the pyrolysis of S. alterniflora or lignite, no obvious CO releasing peak occurred. Nonetheless, FTIR results presented that co-pyrolysis promoted the production of acetic acid, especially for the blends with higher S. alterniflora content. In conclusion, co-pyrolysis of S. alterniflora and lignite can produce a synergetic effect by promoting the production of CH4 and CO, as well as by decreasing activation energy and increasing reaction rate constant of pyrolysis reaction. It should be emphasized that this synergetic effect is mainly reflected by the catalytic effect of S. alterniflora on lignite.