餐厨垃圾特性及其厌氧消化性能研究

以校园餐厨垃圾为原料,分析测定了早餐、午餐和晚餐餐厨垃圾的总固体(TS)、挥发性固体(VS)、碳水化合物、蛋白质、脂肪含量以及无机盐离子浓度,并通过批式厌氧发酵试验对3种餐厨垃圾的厌氧消化性能进行了对比研究。结果表明,早餐餐厨垃圾特性与午餐/晚餐餐厨垃圾差异较大,Na+,Ca2+和Cl-含量高于后两者。餐厨垃圾不同特性对其厌氧消化产气及有机物去除率都有一定影响,早餐、午餐和晚餐餐厨垃圾的累积甲烷产量分别为212.2,331.6和362.4 ml/g,早餐餐厨垃圾产气量比午餐和晚餐餐厨垃圾分别低36%和41.4%,其中Cl-含量高可能是造成其产气量低的主要原因。     

餐厨垃圾中温厌氧发酵接种污泥的驯化研究

研究不同投料方式对餐厨垃圾中温厌氧发酵接种物产气活性的影响,探求餐厨垃圾中温厌氧发酵接种物的最佳驯化方法。在37℃条件下,采用不同投料方式对厌氧污泥进行驯化作为餐厨垃圾厌氧发酵的接种物,分析驯化过程中污泥pH值和SCOD浓度的变化,并用驯化后污泥作为接种物对餐厨垃圾进行中温厌氧发酵处理,研究不同驯化方式对餐厨垃圾产气特性的影响。结果表明:污泥经过添加一定量的餐厨垃圾驯化培养后,产气活性有所提高,其中每天投2.5 g实验物料(厌氧污泥接种体占0.5%),培养20 d后的接种体中生物活性最高,平均产气效率达179.5 mL/d,甲烷气体浓度为59.8%,最终降解率为75.5%。     

混合比对市政污泥与餐厨垃圾二级高温共消化的影响

研究不同混合比下市政污泥与餐厨垃圾二级高温共消化的情况。实验分别采用污泥与餐厨TS之比为3∶1,4∶1,5∶1的3种混合比,主要考查了混合比对二级反应罐的影响。研究表明,不同的混合比对各反应罐达到稳定时出料的COD浓度、VS的含量及其去除率、日产气量以及产气中甲烷含量等都有一定的影响,混合比为3∶1,4∶1,5∶1的反应罐稳定时出料的COD浓度分别为13 500,10 000,23 000mg/L,混合比为4∶1时,出料COD浓度最低。稳定时VS的含量随着混合比的增加而升高,分别为0.034 7,0.039 6,0.045 6g/g物料,VS的去除率分别为42.8%,26.7%,5.2%;稳定时各反应罐的日产气量随着混合比的升高而降低,分别为12 000,5 500,4 500mL,产气中甲烷含量分别为92.49%,91.55%,88.69%。     

餐厨垃圾SBMR-ASBR两相厌氧消化产气性能研究

以学校食堂餐厨垃圾为原料,考察餐厨垃圾在SBMR-ASBR反应器中产酸和产甲烷性能。结果表明:高负荷下启动酸化相有利于系统快速形成稳定的乙醇型发酵,且可以避开丙酸型发酵,在10 g/(L.d)负荷(以VS计)下,稳定状态产酸率平均达到55 000 mg/L,VFA中乙醇和乙酸分别平均稳定在27 000 mg/L和23 000mg/L,两者共占总VFA的91%;甲烷相可以稳定运行的最高负荷为5 g/(L.d)(以VS计),此时,系统整体处理能力为3.3 g/(L.d),单位容积产气率达到2.3 L/(L.d),甲烷含量在65%～70%,TS,VS去除率分别达到77%,83%。在实际工程中可以高负荷启动酸化相,有利于系统形成稳定的乙醇型发酵和高负荷运行的甲烷相。     

水热炭对餐厨垃圾厌氧消化性能影响研究

文章通过餐厨垃圾的批式厌氧消化试验研究了水热炭制备温度和水热炭含量对不同接种比下餐厨垃圾产沼气的影响。研究结果表明：未添加水热炭时,随着接种比由1.5降低到0.5,产气抑制严重,餐厨垃圾的产沼气潜力由383.4 mL/g降低到151.6 mL/g;添加水热炭能够提高产气量,减少产气延滞时间;接种比相同时,沼气总产量随着水热炭添加量的增加而提高;当水热炭（H240）的添加量为30%时,接种比为1.5,1和0.5的试验组的沼气总产量较对照组的最大增加量分别为11.5%,31.7%和81.2%;当水热炭添加量相同时,H240对厌氧消化的促进效果最优,这归功于其表面丰富和活跃的官能团;添加水热炭后,修正Gompertz方程对不同接种比下累积产气量的拟合效果均得到了提高。     

餐厨垃圾与污泥厌氧发酵产气动力学特性研究

对餐厨垃圾、污水厂污泥以及餐厨垃圾与污泥混合甲烷发酵的产气能力与动力学特性进行了实验分析,餐厨垃圾在中温和高温发酵的产甲烷潜能分别是400和426 mL CH4?gVS−1,经过120℃、20 min蒸煮除油后的餐厨垃圾在中温和高温发酵的产甲烷潜能分别是418和531 mL CH4?gVS−1。经Gompertz模型计算,除油后餐厨垃圾的最大产甲烷速率Rmax比除油前提高了49.8%（中温）和19.0%（高温）,但餐厨垃圾中固体有机物的产甲烷速率变化不明显。在餐厨垃圾机械破碎匀浆过程中,部分固体有机物被液化,中、高温发酵产气过程的一级动力学呈现两阶段特征,液相有机物在中温发酵的产甲烷速率（速率常数k = 0.1955 d−1）略快于高温（k = 0.1543 d−1）;而固体有机物在高温条件下的产甲烷速率（k = 0.0804 d−1）快于中温（k = 0.0388 d−1）。除油后餐厨垃圾中的固体有机物和污泥高温发酵的产甲烷速率也快于中温发酵,表明高温发酵有利于提高固体有机物的产气速率。污泥的产气潜能较低,产气速率慢,与餐厨垃圾共发酵有助于调节碱度和防止发酵体系的酸化。     

餐厨垃圾厌氧消化工艺研究

为了提高餐厨垃圾的厌氧消化效率,对餐厨垃圾序批式厌氧消化(BT)、半连续厌氧消化(SCT)、固液两相厌氧消化(SLT)进行了比选研究。研究结果表明,SLT生产系统有效提高了厌氧消化效率,单位沼气产量与甲烷含量也都显著提高,SLT,SCT及BT的单位VS最大沼气日产量分别为430,270 m L和150 m L,最高甲烷含量分别为68%,57%和50%;SLT的产酸效率及有机酸利用率均显著提高,有机负荷率较SCT提高50%,能够达到9 g/(L·d)。餐厨垃圾的SLT工艺有机负荷及消化效率较SCT及BT工艺均有大幅提高。     

构树与不同生物质废弃物混合厌氧发酵产气性能研究

在温度(55±1℃)和总挥发性固体浓度(2%)为固定参数,碳氮比(C/N)为可变参数的条件下,研究了构树和牛粪、餐厨垃圾、水稻秸秆分别进行混合发酵的产气性能。研究结果表明:与单一发酵相比,混合发酵均能提高甲烷产量,当构树与餐厨垃圾混合物的C/N为20时,可获得最高的累积产甲烷量(411.71 mL/g),比构树和餐厨垃圾单独发酵时的累积产甲烷量分别提高了45.45%和12.61%;构树与餐厨垃圾、牛粪、水稻秸秆进行混合发酵时,原料之间均存在协同作用,其中,构树与水稻秸秆在C/N为15的条件下进行混合发酵时,协同指数最高,为18.69%;构树与不同废弃物的混合厌氧发酵过程符合修正Gompertz方程(R~20.97),可用该拟合方程模拟混合厌氧发酵过程。     

餐厨垃圾高温厌氧消化连续运行性能：有机物转化效率、发酵稳定性与代谢活性

在高温 (50±1)℃条件下处理实际工程的餐厨垃圾,采用全混式厌氧反应器（CSTR）进行了80 d的连续试验。试验以水力停留时间（HRT）20 d启动,HRT 15 d连续运行,研究了反应器启动和运行期间的发酵特性,解析了餐厨垃圾厌氧消化运行稳定性和代谢活性。试验结果表明,在HRT 15 d、有机负荷（OLR）为7.3 kg_COD/(m³∙d)的条件下,容积产甲烷率为2.2 L/(L∙d),挥发性固体（VS）的甲烷产率达到480 L/kg_VS左右,有机物转化率约为95%。批次试验表明,高温产甲烷菌代谢乙酸能力较强,在适宜pH下可承受10 000 mg/L的乙酸浓度。餐厨垃圾的高温降解速率快,10 d达到90%的产气,有承受更高负荷的可能。系统pH稳定在7.6 ~ 7.7,总氨氮和自由氨浓度低于抑制水平。研究结果表明,餐厨垃圾的高温厌氧消化可实现较高的产气潜力和有机物去除率,系统稳定性好且有机物转化效率高,具有应用于工程高温餐厨垃圾厌氧处理的潜力。     

有机负荷对厨垃圾厌氧消化系统稳定性的影响

厌氧消化是餐厨垃圾产业化处理的主流方式,酸化是影响餐厨垃圾厌氧消化过程稳定的关键,单位有机负荷是引起酸化的最主要因素.系统研究了不同单位体积有机负荷的产气情况.试验结果表明,在2.5～2.8kg TVS/(m3·d)单位体积有机负荷水平,全混合厌氧消化系统可以获得稳定的高产气率,达到2.55～2.68m3/(m3·d).当单位体积有机负荷进一步提高,系统内挥发性脂肪酸总量、pH值、碱度和沼气中甲烷含量急剧下降,体系迅速转向酸化.     

Microbial oil production from thermophile cyanobacteria for biodiesel production

Compared to lipid extraction from algae, little work has been performed for cyanobacteria. In this article it is aimed to show high lipid accumulation potential of Synechococcus sp., Cyanobacterium aponinum and Phormidium sp. cells in BG-11 medium. Four different pH values (6–9) and NaNO₃ (0.25, 0.5, 1.0, 1.5 g/L) concentrations were examined at different incubation days to discover the highest lipid accumulation. The maximum lipid content could be achieved in the medium containing 0.25 g/L NaNO₃ at pH 7 for Synechococcus sp., pH 8 for C. aponinum and pH 9 for Phormidium sp. after 15 days. The maximum lipid contents and C16 and C18 methyl ester yields were measured as 42.8% and 46.9% for Synechococcus sp., 45.0% and 67.7% for C. aponinum, 38.2% and 90.6% for Phormidium sp. The saturated compounds were 74.5%, 77.9%, 84.7% for Synechococcus sp., C. aponinum and Phormidium sp., respectively. These crude lipids could be promising feedstock for biodiesel production.     

太阳能制氢技术

近几年来，随着质子交换膜氢燃料电池技术获得前所未有的进展，氢燃料电池被视为最具潜力的环保汽车动力源，逐步走向商品化。氢燃料电池是利用氢和氧（或空气）直接经电化学反应产生电能。氢也可以直接燃烧放热。氢的热值（１４２０００kJ／kg）是石油热值（４８０００kJ／kg）的３倍。而且，氢的燃烧产物主要是水，具有无污染、无毒等环保优势，是矿物燃料无法比拟的。此外，科学家研究表明，在石油中加入５％的氢，可提高效率２０％，并减少９０％的致癌物；若用管道传送氢气到五六百公里外，要比电线输送同等能量的电力便宜九成。科学…     

Alkaline catalyzed biodiesel production from moringa oleifera oil with optimized production parameters

The utilization of non-edible feedstock such as moringa oleifera for biodiesel production attracts much attention owing to the issue with regards to avoiding a threat to food supplies. In this study, the optimization of biodiesel production parameters for moringa oleifera oil was carried out. The free fatty acid value of moringa oil was found to be 0.6%, rendering the one step alkaline transesterification method for converting moringa fatty acids to their methyl esters possible. The optimum production parameters: catalyst amount, alcohol amount, temperature, agitation speed and reaction time were determined experimentally and found to be: 1.0 wt% catalyst amount, 30 wt% methanol amount, 60 °C reaction temperature, 400 rpm agitation rate and 60 min reaction time. With these optimal conditions the conversion efficiency was 82%. The properties of the moringa biodiesel that was produced were observed to fall within the recommended international biodiesel standards. However, moringa biodiesel showed high values of cloud and pour points of 10 °C and 3 °C respectively, which present a problem as regards use in cold temperatures.     

Continuous biohydrogen production using cheese whey: Improving the hydrogen production rate

Due to the renewed interest in finding sustainable fuels or energy carriers, biohydrogen (Bio-H₂) from biomass is a promising alternative. Fermentative Bio-H₂ production was studied in a continuous stirred tank reactor (CSTR) operated during 65.6 d with cheese whey (CW) as substrate. Three hydraulic retention times (HRTs) were tested (10, 6 and 4 h) and the highest volumetric hydrogen production rate (VHPR) was attained with HRT of 6 h. Therefore, four organic loading rates (OLRs) at a fixed HRT of 6 h were tested thereafter, being: 92.4, 115.5, 138.6 and 184.4 g lactose/L/d. The highest VHPR (46.61 mmol H₂/L/h) and hydrogen molar yield (HMY) of 2.8 mol H₂/mol lactose were found at an OLR of 138.6 g lactose/L/d; a sharp fall in VHPR occurred at an OLR of 184.4 g lactose/L/d. Butyric, propionic and acetic acids were the main soluble metabolites found, with butyric-to-acetic ratios ranging from 1.0 to 2.4. Bacterial community was identified by partial sequence analysis of the 16S rRNA and polymerase chain reaction–denaturing gradient gel electrophoresis (PCR–DGGE). The results showed that at HRT of 10 h and 6 h were dominated by the Clostridium genus. The VHPR attained in this study is the highest reported value for a CSTR system using CW as substrate with anaerobic sludge as inoculum and represents a 33-fold increase compared to a previous study. Thus, it was demonstrated that continuous fermentative Bio-H₂ production from CW can be significantly enhanced by an appropriate selection of parameters such as HRT and OLR. Enhancements in VHPR are significant because it is a critical parameter to determine the full-scale practical application of fermentation technologies that will be used for sustainable and clean energy generation.     

Innovation in hydrogen production

In this study, the critical perspectives of innovation are introduced for specifically for hydrogen production under a new concept (so-called: 18S concept), covering source, system, service, scope, staff, scale-up, safety, scheme, sector, solution, stakeholder, standardization, subsidy, stimulation, structure, strategy, support and sustainability. The roles of these specific conceptual items are discussed, and their importance is highlighted. Furthermore, the innovative methods in hydrogen production are assessed by using a ranking method for comparison and evaluation purposes. The results show that renewable sources, particularly hydro, geothermal and solar show a unique potential to support these innovative H₂ production systems. When the H₂ production systems are compared, the ones supporting heat recovery (thermal) and the photonic based options show better performance in terms of emissions, cost and efficiency.     

Integrated biological hydrogen production

Biological systems offer a variety of ways by which to generate renewable energy. Among them, unicellular green algae have the ability to capture the visible portion of sunlight and store the energy as hydrogen (H₂). They hold promise in generating a renewable fuel from nature's most plentiful resources, sunlight and water. Anoxygenic photosynthetic bacteria have the ability of capturing the near infrared emission of sunlight to produce hydrogen while consuming small organic acids. Dark anaerobic fermentative bacteria consume carbohydrates, thus generating H₂ and small organic acids. Whereas efforts are under way to develop each of these individual systems, little effort has been undertaken to combine and integrate these various processes for increased efficiency and greater yields. This work addresses the development of an integrated biological hydrogen production process based on unicellular green algae, which are driven by the visible portion of the solar spectrum, coupled with purple photosynthetic bacteria, which are driven by the near infrared portion of the spectrum. Specific methods have been tested for the cocultivation and production of H₂ by the two different biological systems. Thus, a two-dimensional integration of photobiological H₂ production has been achieved, resulting in better solar irradiance utilization (visible and infrared) and integration of nutrient utilization for the cost-effective production of substantial amounts of hydrogen gas. Approaches are discussed for the cocultivation and coproduction of hydrogen in green algae and purple photosynthetic bacteria entailing broad utilization of the solar spectrum. The possibility to improve efficiency even further is discussed, with dark anaerobic fermentations of the photosynthetic biomass, enhancing the H₂ production process and providing a recursive link in the system to regenerate some of the original nutrients.     

Hydrogen production using sono-biohydrogenator

Hydrogen production in a novel sonicated biological hydrogen reactor (SBHR) was investigated and compared with a continuous stirred tank reactor (CSTR). The two systems were operated at a hydraulic retention time (HRT) of 12 h and two organic loading rates (OLRs) of 21.4 and 32.1 g COD/L.d. The average hydrogen production rates per unit reactor volume for the conventional CSTR were 2.6 and 2.8 L/L.d, as compared with 4.8 and 5.6 L/L.d for SBHR, at the two OLRs, respectively. Hydrogen yields of 1.2 and 1.0 mol H₂/mol glucose were observed for the CSTR, respectively, while for the SBHR, the hydrogen yields were 2.1 and 1.9 mol H₂/mol glucose at the two OLRs, respectively. The hydrogen content in the SBHR’s headspace was higher than that in CSTR by 10% and 31% at OLRs of 21.4 and 32.1 g COD/L.d, respectively. Both glucose conversion efficiency and HAc/HBu ratio in the SBHR were higher than in the conventional CSTR at both OLRs. The biomass yield of about 0.32 g VSS/g COD observed in the CSTR and 0.23 g VSS/g COD in the SBHR substantiate the higher H₂ yield in the SBHR. DGGE analysis confirmed the specificity of the microbial hydrogen-producing culture in the SBHR, with two different hydrogen producers (Clostridium sp. and Citrobacter freundii) detected in the SBHR and not detected in the CSTR.     

我国太阳热水器产业

我国的太阳热水器产业，从无到有、从小到大，随着市场需求的迅速增长和公众环保意识的不断加强而不断发展，已成为我国可再生能源领域发展最快、规模最大、市场成熟最早的行业。特别是近几年来，在“生产上规模、技术上水平、产品上质量和市场要规范”的产业发展思路引导下，经广大企业和企业家的艰苦创业，开发市场，使太阳热水器产业迅速发展，初步形成原材料业、加工制造业和销售安装服务业相互配套的产业化体系。１ 太阳热水器产业总体规模 我国具有丰富的太阳能资源和良好的开发基础，我国的太阳能年辐照总量超过５０２万ｋＪ。据不完…     

Solar synthetic fuel production

In this paper, a thermodynamic study is presented on solar hydrogen production using concentrated solar energy. In the first part, the direct decomposition process has been studied. The temperature requirements at various partial pressures of H₂O, H₂ and H yields, thermal efficiency and separation of products are discussed. In the second part, using consistent costing bases, the cost of hydrogen is estimated for solar-direct decomposition process and solar-electrolysis process. It has been found that the solar-direct decomposition process concept provides hydrogen costs in the range of $22/GJ which are lower by $15–$26 than those provided by a solar electrolysis process.