农业工程学报
農業工程學報
농업공정학보
2013年
15期
215-222
,共8页
活性炭%温度%吸附%物理活化%ZnCl2活化%高温低氧烟道气
活性炭%溫度%吸附%物理活化%ZnCl2活化%高溫低氧煙道氣
활성탄%온도%흡부%물리활화%ZnCl2활화%고온저양연도기
activated carbon%temperature%adsorption%physical activation%ZnCl2 activation%low oxygen flue gas
为降低污泥制备活性炭的成本，以高温低氧烟道气为媒介，研究了活化时间、温度、蒸气含量以及氧含量对污泥活性炭性能的影响规律，结果表明：活化温度、活化时间及水蒸气流量的最佳值分别为800°C、90 min和34.8%，该条件下污泥活性炭比表面积、产率、甲基橙及亚甲基蓝吸附值分别为：246.3 m2/g、46%、14.8 mg/g、18.1 mg/g。因而，高温低氧烟气直接用于物理活化法制备污泥活性炭，活化气量（水蒸汽）不够，产品活性炭的性能差，活化温度高达800°C，运行成本仍偏高。将湿污泥用ZnCl2按1∶1浸渍16 h后活化炭化，在活化温度、活化时间、氧含量分别为550°C、90 min、2%时，污泥活性炭的产率为59%，其比表面积和亚甲基蓝吸附值分别达516.1 m2/g和129.8 mg/g，孔体积为0.29 cm3/g，微孔体积为0.16 cm3/g，平均孔径为3.95 nm，性能较好。氧气能促进活性炭微孔的形成与发展，最佳的氧含量为2%~4%。与无氧条件下制备的污泥活性炭相比，氧含量为4%时制得的污泥活性炭的比表面积增加了6.82%，亚甲基蓝吸附值提高了2.75倍。该研究表明：高温烟气作为热源、保护气和活化气，结合化学活化法，可将脱水湿污泥直接制成污泥活性炭。该结果可为低成本制备污泥活性炭、实现污泥处理的资源化利用提供一定的参考。
為降低汙泥製備活性炭的成本，以高溫低氧煙道氣為媒介，研究瞭活化時間、溫度、蒸氣含量以及氧含量對汙泥活性炭性能的影響規律，結果錶明：活化溫度、活化時間及水蒸氣流量的最佳值分彆為800°C、90 min和34.8%，該條件下汙泥活性炭比錶麵積、產率、甲基橙及亞甲基藍吸附值分彆為：246.3 m2/g、46%、14.8 mg/g、18.1 mg/g。因而，高溫低氧煙氣直接用于物理活化法製備汙泥活性炭，活化氣量（水蒸汽）不夠，產品活性炭的性能差，活化溫度高達800°C，運行成本仍偏高。將濕汙泥用ZnCl2按1∶1浸漬16 h後活化炭化，在活化溫度、活化時間、氧含量分彆為550°C、90 min、2%時，汙泥活性炭的產率為59%，其比錶麵積和亞甲基藍吸附值分彆達516.1 m2/g和129.8 mg/g，孔體積為0.29 cm3/g，微孔體積為0.16 cm3/g，平均孔徑為3.95 nm，性能較好。氧氣能促進活性炭微孔的形成與髮展，最佳的氧含量為2%~4%。與無氧條件下製備的汙泥活性炭相比，氧含量為4%時製得的汙泥活性炭的比錶麵積增加瞭6.82%，亞甲基藍吸附值提高瞭2.75倍。該研究錶明：高溫煙氣作為熱源、保護氣和活化氣，結閤化學活化法，可將脫水濕汙泥直接製成汙泥活性炭。該結果可為低成本製備汙泥活性炭、實現汙泥處理的資源化利用提供一定的參攷。
위강저오니제비활성탄적성본，이고온저양연도기위매개，연구료활화시간、온도、증기함량이급양함량대오니활성탄성능적영향규률，결과표명：활화온도、활화시간급수증기류량적최가치분별위800°C、90 min화34.8%，해조건하오니활성탄비표면적、산솔、갑기등급아갑기람흡부치분별위：246.3 m2/g、46%、14.8 mg/g、18.1 mg/g。인이，고온저양연기직접용우물리활화법제비오니활성탄，활화기량（수증기）불구，산품활성탄적성능차，활화온도고체800°C，운행성본잉편고。장습오니용ZnCl2안1∶1침지16 h후활화탄화，재활화온도、활화시간、양함량분별위550°C、90 min、2%시，오니활성탄적산솔위59%，기비표면적화아갑기람흡부치분별체516.1 m2/g화129.8 mg/g，공체적위0.29 cm3/g，미공체적위0.16 cm3/g，평균공경위3.95 nm，성능교호。양기능촉진활성탄미공적형성여발전，최가적양함량위2%~4%。여무양조건하제비적오니활성탄상비，양함량위4%시제득적오니활성탄적비표면적증가료6.82%，아갑기람흡부치제고료2.75배。해연구표명：고온연기작위열원、보호기화활화기，결합화학활화법，가장탈수습오니직접제성오니활성탄。해결과가위저성본제비오니활성탄、실현오니처리적자원화이용제공일정적삼고。
Sludge treatment and disposal have been a significant environmental problem because of the huge yield due to the high-speed urbanization and industrialization in China. Recently, in virtue of potential energy contained in organic matters of sewage sludge, thermal conversion technologies, such as pyrolysis, gasification, combustion and some high value-added products production, have been recognized as promising methods to deal with sludge aiming at energy recovering. Among them, sludge-derived activated carbon had been developed and worked as one of the most effective methods to realize the harmless sludge treatment and energy recycling simultaneously. However, the cost of the sludge-based activated carbon production was still high due to the huge amount of heat and gas required during the carbonization and activation. Therefore, this study proposed to produce the sludge-derived activated carbon with flue gases. The feasibility of exploiting low oxygen flue gas to prepare activated carbon from the sludge was investigated by focusing on the operating conditions, such as the activation method (physical activation and ZnCl2 activation), activation temperature, activation time, steam content, the ratio of sludge to ZnCl2 and oxygen content. The Brunauer-Emmett-Teller (BET) surface area and the adsorption value of the methylene blue and methyl orange of the derived activated carbon were taken as the indexes to evaluate its performance. The results showed that the optimal operating parameters of activation temperature, activation time and steam content were 800°C, 90 min and 34.8%respectively for the physical activation. However, the products were not so good comparing with the commercial products. The BET surface area, the yield of activated carbon, and the adsorption value of methylene blue and methyl orange were only 246.3 m2/g, 46%, 18.1 mg/g and 14.8 mg/g respectively. It was indicated that the single use of flue gas was not sufficient for physical activation of sludge to produce activated carbon due to its low vapor content and high operation cost to support the energy demands of high activation temperature. Some other activation method should be incorporated or modified to improve the thermal efficiency of this whole process as well the performance of sludge-based activated carbon. In respect to the ZnCl2 activation, the existence of oxygen can promote formation and development of the microspores of activated carbon. The BET surface area of the products produced under an oxygen content of 4%, was improved 6.82% comparing with what was prepared without oxygen. Correspondingly, the adsorption properties were improved with an increment of 2.75 times in the adsorption value of methylene blue. The optimal oxygen content was about 2%-4% for ZnCl2 activation. Under the optimal condition of activation temperature 550°C, activation time 90 min and oxygen content 2%, the yield of sludge-derived activated carbon as 59%;its BET surface area and methylene blue adsorption value were the highest of 516.1 m2/g and 129.8 mg/g, respectively;the pore volume, microspore volume and average pore size were 0.29 cm3/g, 0.16 cm3/g and 3.95 nm, respectively. All the data demonstrated that combination with chemical activation, the flue gas with high temperature and low oxygen content could be used as a heat resource, shielding gas and activation agent to produce activated carbon from dewatered sludge with moisture content higher than 80%directly. This study could provide a theoretical basis to lower the cost of sludge-derived activated carbon production from dewatered sewage sludge. It also provided a viable option to realize the harmless sludge treatment and cost-effective energy recycling simultaneously.
