蜈蚣草水热液化后处理及生物油改性

以典型砷超富集植物——蜈蚣草茎叶收获物为研究对象,开展了水热液化后处理及粗生物油改性实验研究。在粒度75μm、液固比6.7∶1、温度380℃、压强25 MPa条件下,对蜈蚣草进行水热液化后处理后,蜈蚣草茎叶中91.51%以上的重金属进入水溶液,68.56%的生物质转化为粗生物油。经GC-MS检测,粗生物油中有机物成分主要为苯环类23.79%、烷烃类13.96%、酯类20.75%、醇类3.10%、酮类25.11%、烯烃类7.19%;以正十二烷为溶剂,在温度150℃、时间2 h、氢压1.0 MPa以及钯碳催化剂5%的条件下对粗生物油进行催化加氢改性,得到的改性生物油含苯环类1.17%、烷烃类87.75%、酯类1.26%、醛酮类2.70%、烯烃类2.71%。经改性后,粗生物油中苯环类有机物大幅降低,烷烃类有机物大幅增长,热值由38.86 MJ·kg~(-1)提高到46.85 MJ·kg~(-1),有利于生物油的能源化利用。     

废弃物生物质液化制取生物油的研究进展

废弃物生物质处置不当引起的环境污染与潜在资源浪费已引起了广泛关注,而废弃物生物质液化制取生物油是解决有机废弃物污染及其能源化再利用的一种新技术。在对多糖、木质素、蛋白质、油脂等生物质大分子聚合物的液化机制阐述分析的基础上,讨论了温度、加热速度、粒径、压强、停留时间、液固质量比,特别是催化剂以及还原气和供氢剂等反应条件或参数对生物油的影响机制,最后介绍了生物质液化油的物理化学性质以及该技术存在的若干问题。     

碱性催化剂对农业废物液化产生生物油和气体的影响

采用热化学处理法对农业废物玉米秸秆和苹果渣进行处理,3种碱性物质Na2CO3、K2CO3和KOH作为催化剂,都能不同程度提高液化生物油收率、减少固体残渣收率.但碱性催化剂会降低气体收率,因而不适合作为以获得气体产物为目的的生物质气化试验的催化剂.就增加液化生物油收率方面而言,Na2CO3的催化效果最好,KOH催化效果次之,K2CO3的催化效果最差.     

离子液体催化木质素转化制备丁香醛

木质素的高值转化对于生物质的全组分利用具有重要意义,直接关乎生物炼制产业链的经济可行性。离子液体作为一种新型催化剂,具有较高的可设计性、结构稳定性和热稳定性,可用于木质素催化转化制备具有高附加值的小分子产物以提高木质素的利用效率。以乙醇胺类和胍类离子液体为催化剂,考察了木质素种类与用量、催化剂种类与浓度、反应温度和pH值等因素对丁香醛收率的影响。结果表明:当催化剂为乙醇胺四氟硼酸盐[MEA]BF4,木质素与催化剂用量比为2∶1,固液比1∶150,温度160℃,pH=4.35,反应6 h后丁香醛收率最高,为9.20%。     

生物质快速热裂解主要参数对生物油产率的影响

以松木木屑为原料,在自制的小型流化床上,开展了生物质热裂解温度、生物质粒径和进料速率对生物油产率的影响实验研究.结果表明,在热裂解温度分别为450、475、500、525和550℃条件下,当热裂解温度为500℃时,生物油产率最高,平均产率达到53.33%(质量百分比).反应温度越高,炭产量越低,不可冷凝气体产量越高,气体发热值越高;粒径＜1 mm的生物质其粒径对生物油产率影响不大;生物质进料速率增加时,生物油产率增加.本研究为生物能的利用提供了新的途径.     

生物沥浸含锰烟粉尘中的锰及其浸出机理研究

含锰烟粉尘是钢铁行业产生的一类含有锰、锌、铅和硅等元素的工业固废，既存在一定的环境风险，又具有潜在的资源回收价值。对含锰烟粉尘分别用生物酸和无机酸进行沥浸，分析锰的浸出机理，进一步通过响应面法确定生物酸沥浸锰的最佳工艺条件。结果表明，锰的浸出机理为酸溶和生物酸还原的复合机理，生物酸中的还原性物质和沥浸过程中产生的Fe²⁺能够将高价锰还原为Mn²⁺,使生物酸体系锰的浸出率比无机酸体系高。生物酸浸出锰的最佳工艺条件：固液比为1.22 g∶100 mL,初始pH为0.81,温度为29.14℃,转速为152.29 r/min,此条件下实际锰浸出率为76.51%。     

响应面法优化超临界CO_2流体处理油基钻屑工艺

采用超临界CO2流体处理油基钻屑,考察了萃取温度、萃取压力以及分离温度对油基钻屑油相回收率的影响,在单因素实验基础上,应用响应面法最终确定超临界CO2流体处理油基钻屑的最佳条件为:萃取压力21 MPa,萃取温度55℃,分离温度64℃。各因素对油相回收率的影响依次为:萃取压力分离温度萃取温度。在最佳条件下,油相回收率为99.65%,处理后废渣油相含量0.08%,满足《农用污泥中污染物控制标准》(GB 4284-84),同时达到GB18599-2001的Ⅱ类固废物要求,可安全处置。     

生物质快速热裂解主要参数对生物油产率的影响

以松木木屑为原料,在自制的小型流化床上,开展了生物质热裂解温度、生物质粒径和进料速率对生物油产率的影响实验研究.结果表明,在热裂解温度分别为450、475、500、525和550℃条件下,当热裂解温度为500℃时,生物油产率最高,平均产率达到53.33%（质量百分比）.反应温度越高,炭产量越低,不可冷凝气体产量越高,气体发热值越高;粒径＜1 mm的生物质其粒径对生物油产率影响不大;生物质进料速率增加时,生物油产率增加.本研究为生物能的利用提供了新的途径.     

生物质碳基固体酸催化剂的制备及其对酯化反应的催化性能

为了寻找一种以生物质为原料,能够温和地合成磁性碳基固体酸催化剂的路径,以生物质柚子果皮为原料合成磁性固体酸催化剂,并将其用于催化油酸和乙醇的酯化反应中。结果表明:MPC-0.4-SO_3H和MPC-0.8-SO_3H在反应温度为80℃、催化剂用量为油酸质量的7%、油醇比为1∶20、反应时间为8 h时,酯化率可达到68.0%和68.8%,高于商用催化剂Amberlyst-15的酯化率;2种催化剂耐水性好,稳定性高,重复使用3次和4次时,酯化率仍高于或接近Amberlyst-15。通过分析可知,2种固体酸活化能较低,与Amberlyst-15相比,其催化反应的速率常数更大,在生物柴油的合成中具有较好的应用前景。     

油菜秸秆直接液化为液体油工艺探讨

为了实现油菜秸秆的综合利用,将其在高温高压下催化液化制备液体油。结果表明:(1)油菜秸秆中的纤维素、半纤维素、木质素质量分数分别为25.45%、11.57%、28.73%,木质素最高,其次是纤维素。(2)油菜秸秆和残渣元素分析可知,液化反应前后油菜秸秆各元素含量无明显变化,热值(HHV)分别为10.58、10.47MJ/kg。(3)硫酸盐催化作用优于氯化物催化剂,硫酸铁和硫酸亚铁在中性反应溶剂条件下催化效果较佳,特别是在酮类反应溶剂中。在实验条件为固液比1.0∶19.3(油菜秸秆与混合溶剂的质量比)、反应时间4h、催化剂用量1%(质量分数)、丙酮作反应溶剂、硫酸铁作催化剂时,转化率可达47.106%。(4)预先将油菜秸秆浸泡在1%(质量分数)KOH溶液中12h,对生物质中纤维素、半纤维素和木质素有溶胀作用,能提高转化率。(5)通过热重(TG)/差热(DTG)曲线分析,残渣的燃烧反应性更好,活化能略低于油菜秸秆。     

小球藻(Chlorella vulgaris)净化沼液和提纯沼气

为了研究同时提纯沼气和净化沼液的可能,利用沼液作为小球藻(Chlorella vulgaris)的培养基,同时把沼气中的CO2作为小球藻培养的碳源。在无菌培养条件下,得出了最适生长条件为沼液浓度50%、初始pH值6.0、接种小球藻干重为0.20 mg/mL、光质为红光。在此条件下沼液中的COD、TN、TP和BOD5的去除率分别达到了88.5%、91.2%、95.3%和87.6%,沼气中甲烷含量由原先的40%提升到60.2%。很好地同时解决了沼气品质低下和高浓度污染物沼液污染环境的问题。     

Evaluation of biogas upgrading technologies and future perspectives: a review

Environmental Science and Pollution Research - Biogas is acknowledged as one of the foremost bioenergy to address the current environmental and energy challenges being faced by the world. Commonly,...     

微孔曝气氧化沟工艺问题诊断及分析

污水厂升级改造仍是目前水处理研究的热点问题,通过桂林七里店污水厂的微孔曝气氧化沟处理过程进行诊断分析,结果表明,将七里店污水厂微孔曝气氧化沟的一个A/O运行模式改造为2个分段A/O供氧模式,改变进水点,提高氧化沟内梯度脱氮环境,缺氧区和好氧区容积比调整为1∶1.2,氧化沟出水口DO浓度到0.5 mg/L以上,二沉池中NO-3-N平均浓度达到7.2 mg/L,氧化沟到二沉池出水口阶段NH+4-N和PO3-4-P的平均释放量由改造前的3.85和1.69mg/L降低到-0.1和-0.2 mg/L的无释放状态。同时也表明,二沉池中NO-3-N浓度适当可抑制沉淀池中氨氮和磷酸盐的释放,改善出水水质。     

Sustainability considerations in remediation,retrofit, and seismic upgrading of historic masonry structures

This paper addresses the problem of sustainability in remediation, retrofit, and seismic upgrading of historic masonry structures. Different rehabilitation techniques and some successful applications throughout the Balkans and Italy are described, with particular emphasis to the shear reinforcement of wall panels. The selected techniques aim at improving the seismic performance, preserving the structures for future generations, having the least impact in altering the architectural and heritage values, as well as being sustainable, in terms of reduced carbon dioxide emissions, reversibility, and low energy consumption. The use of cross-laminated timber (CLT), natural fibers, and fiber-reinforced Polymers (FRP) jacketing with natural lime coatings are discussed. The paper concludes by summarizing key successes of the proposed rehabilitation solutions in conservation engineering and suggests areas in which these could be used with great advantage.

     

Wastewater characterisation and performance upgrading of a domestic wastewater treatment plant: the Erzincan case

A detailed characterisation of the incoming wastewater and a performance evaluation were carried out for the domestic wastewater treatment plant of Erzincan City. Conventional characterisation results showed that Erzincan has a medium strength wastewater quality. Structural characterisation of the chemical oxygen demand (COD) indicated that the biodegradable fraction of the total COD was 64.7%. The soluble inert fraction was computed as 10.9% of the total COD. In Erzincan, an activated sludge plant provides secondary treatment using Carrousel treatment units. Because some operational problems, such as sludge bulking and foaming, have been experienced, and performance failures related to carbonaceous matter removal have been recorded many times, a new operational strategy suitable for this type of treatment plant was developed. In the new strategy, the sludge age was kept at 22 days, intermittent aeration was abandoned and replaced by continuous aeration, and the sludge recycle ratio was increased to 1.35 from 0.85. The developed operational strategy showed its merit in that previous operational problems largely disappeared and COD concentrations remained below the Turkish discharge limits of 100 mg/l and the NH₄ removal rate was in the range 87–95%.     

双循环两相生物处理工艺对循环式活性污泥法工艺升级改造的探讨

循环式活性污泥法(CASS)存在微生物的混合培养、泥龄、硝酸盐等问题,制约系统脱氮除磷效率的进一步提高.双循环两相生物处理(BICT)工艺以CASS工艺为基础,通过单独设立膜法硝化池,使自养菌和异养菌分开培养,解决了微生物混合生长所带来的问题,同时BICT工艺中间歇反应器与连续流反应器的特殊组合方式使污泥在序批式活性污泥法(SBR)各池间转移,可增加系统充水比和提高容积利用率.保证BICT工艺具有良好的氮、磷去除效果.利用BICT工艺对CASS工艺进行工程升级改造,比利用物化法对CASS工艺进行改造所需投资省、运行费用低.在对CASS工艺进行改造时,可以优先考虑BICT工艺.     

面向寒冷地区城镇污水处理厂提标改造的ASM模拟优化及其应用

为指导和支撑寒冷地区城镇污水厂升级改造,采用GPS-X软件的ASM1模型,构建了河北某污水处理厂CASS工艺提标改造模型,分别对污泥回流比(R_S)、反应区体积比(R_V)、充水比(λ)、运行周期(T)和不同水温的CASS运行方案等进行了数值模拟优化;同时,综合模拟结果,提出了升级改造技术方案,并予以实施。冬季运行结果表明,改造后的CASS工艺出水指标COD、氨氮和TN的浓度分别为(23.23±2.76)、(1.16±0.76)、(9.83±1.4) mg·L~(-1),能够稳定达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准。     

Nutrient removal from biogas slurry and biogas upgrading by microalgae-fungi-bacteria co-cultivation under different carbon nanotubes concentration

In this study, Chlorella vulgaris, Ganoderma lucidum, and endophytic bacteria were co-cultivated with the stimulation of strigolactone analogs GR24 to prepare pellets. During the purification of biogas slurry and biogas, multi-walled carbon nanotubes (MWCNTs) were introduced to enhance the removal efficiencies of nutrients and CO₂. The results showed that both GR24 and MWCNTs affected the purification of biogas slurry and biogas. The maximum chemical oxygen demand, total nitrogen, total phosphorus, and CO₂ removal efficiencies of the Chlorella vulgaris-Ganoderma lucidum-endophytic bacterial symbionts were 82.57 ± 7.96% (P < 0.05), 82.14 ± 7.87% (P < 0.05), 84.27 ± 7.96% (P < 0.05), and 63.93 ± 6.22% (P < 0.05), respectively, with the induction of 10⁻⁹ M GR24 and 1 mg L⁻¹ MWCNTs. Moreover, the growth and photosynthetic performance of the symbionts were consistent with the removal effects. The Chlorella vulgaris-Ganoderma lucidum-endophytic bacterial symbionts obtained high growth rates and enzyme activity with the maximum growth rate of 0.365 ± 0.03 d⁻¹, mean daily productivity of 0.182 ± 0.016 g L⁻¹ d⁻¹, and carbonic anhydrase activity of 31.07 ± 2.75 units, respectively. These results indicated that an appropriate concentration of GR24 and MWCNTs could promote the growth of symbionts, reinforce the purification effects of biogas slurry and biogas, and provide a new idea for the simultaneous purification of wastewater and biogas.

     

MCR—O_3—BAC组合工艺在工业园区污水处理厂提标改造中的运用研究

以膜混凝反应器(MCR)—O3—生物活性炭(BAC)组合工艺作为出水提标改造工艺,在浙江某工业园区污水处理厂进行了现场试验,考察了组合工艺对有机物和色度的去除情况,并验证了膜过滤(MCR工艺段)在组合工艺中的作用。结果表明,MCR工艺段对COD和色度均有不同程度的去除,去除效果均与进水SS浓度有关;MCR—O3—BAC组合工艺运行中,COD去除率最高的是在BAC工艺段,稳定运行阶段(70~90d左右,下同)最终出水COD基本不超过50mg/L,色度去除率最高的主要是在O3工艺段,去除率达到37.5%~68.8%,稳定运行阶段最终出水色度小于30倍,均符合《城镇污水处理厂污染物排放标准》(GB18918—2002)一级A标准;通过定期的清洗维护,MCR系统中膜可以在35L/(m2·h)的通量下稳定运行,维护性清洗周期为20~30d;MCR工艺段的引入可以显著减少O3的消耗量。     

How industrial upgrading can improve China’s air quality: empirical analysis based on multilevel growth model

Environmental Science and Pollution Research - With the rapid development of industrialization and urbanization in China, the ecological environment has been damaged, especially the air quality,...