碱脱硅改性的HZSM-5分子筛催化裂解小球藻的研究

用NaOH水溶液对HZSM-5分子筛进行脱硅改性。通过XRD、N_2物理吸附、NH_3-TPD对脱硅前后的HZSM-5分子筛进行表征,并研究脱硅改性前后分子筛对小球藻催化裂解的影响规律。结果表明:在适宜的温度和相同的碱处理时间下,改变NaOH水溶液的浓度,能调节分子筛晶体中产生的介孔比例并改变分子筛酸性能;以0.3 mol/L NaOH溶液在80℃下处理2 h改性制备的HZSM-5分子筛催化剂,其表面酸量增加、酸强度降低,有利于反应;小球藻催化热解产物中的氧大部分以CO和CO_2的形式脱除,可有效降低生物油的含氧量;裂解液体产率和生物油热值分别为46.83%、32.851 MJ/kg,生物油中烃类物质总量达到40.34%(质量分数),羰基化合物和醇类物质明显减少。     

电晕氧化结合化学吸收脱除烟气中NOx的研究

研究了直流电晕H2O—O2自由基簇射氧化结合26％的NaOH溶液吸收脱除烟气中的NOx研究表明：通过调节喷嘴电极氧气流量，可得到稳定的流光电晕；在反应器内同时有HNO2和HNO3生成，DeNOx效率最高可迭70％以上；NaOH溶液对NO吸收率较低，而对NO2的吸收率很高；经吸收液吸收后总DeNOx效率最高可迭90％。     

废弃植物油再生利用的研究

文章介绍了用废弃植物油经酯交换反应制成柴油替代燃料的方法和工艺流程，并讨论了提高反应产率的最佳工艺参数。研究表明：在反应温度为70℃，当油醇的物质的量比为1：6，以NaOH为催化剂且浓度为1．0％，反应时间为20～30min时，酯交换反应制取脂肪酸甲酯(生物柴油)的产率为92％。用废弃植物油转化制成的脂肪酸甲酯，是石化柴油很好的替代能源。     

日本科学家发现牛粪可以变汽油

东京大学农业和科技项目研究小组称，通过便用高压和加热技术，他们已经成功地从每3．5盎司的牛粪中提取出0．042盎司的汽油。科研人员将牛粪放进一个容器，再向其中加入了几种金属催化剂，然后对容器实施高温和高压，最终成功提取出了少量的汽油。日本每年会产生大约551155t牛粪。科研人员透露，他们将会继续改进这项技术，以便能够在5年内用于商业用途。     

CaSO4在不同气氛下分解特性的实验研究

通过热重非等温实验研究了不同气氛下CaSO4的分解反应特性，利用红外光谱仪分析反应析出的气体成分。在实验所用的不同非还原气氛中，CaSO4在O2／CO2气氛下的热稳定性最好，其次是O2／N2气氛、CO2气氛、N2气氛。此外，还发现氧气的存在提高了CaSO4热稳定性，抑止了CaSO4的分解。CO气氛下CaSO4的分解反应为平行竞争反应，反应同时生成CaO和CaS。在0．5％CO浓度下，CaSO4分解最终产物主要以CaO为主，CaS的质量百分比仅为28．85％。在4％CO气氛下，反应初期分解产物主要为CaO。后期分解产物主要为CaS，最终反应产物中CaS的质量百分比为57．04％。图6表1参5     

大豆油制备生物柴油的工艺探索

试验研究了大豆油在催化剂（NaOH）的作用下与甲醇发生转脂化反应生成脂肪酸甲酯（生物柴油）的工艺条件。试验结果表明，该转脂化反应的最佳操作条件：NaOH用量为大豆油量的1％、油醇摩尔比为1：6、搅拌时间为50min、反应温度为50～60℃、水的含量必须控制在油重的0．1％以下。     

牛粪、鸡粪发醇产氢潜力的研究

采用恒温厌氧发酵工艺，用乳酸调控发酵pH值，进行了牛粪和鸡粪发酵产氢的实验研究。实验结果表明，pH为4．7～5．5时，牛粪的产氢潜力为32.33ml／g(TS)和41.39ml／g(VS)；鸡粪的产氢潜力为33．58ml／g(TS)和50．88ml／g(VS)。     

湿牛粪催化热解制取富氢气体

以SiO_2、CaO、牛粪灰以及K_2CO_3为催化剂,对湿牛粪进行热解气化制富氢气体的试验研究。结果表明,各催化剂对牛粪热裂解反应催化作用的强弱顺序依次为K_2CO_3牛粪灰CaOSiO_2。在催化反应过程中,SiO_2的催化方向是牛粪热解液化产焦油方向而非热解气化产热解气方向,CaO对牛粪热解产焦油和产热解气均具有较好的催化作用,牛粪灰的催化作用主要表现在焦炭与水蒸气的蒸汽重整反应上,而K_2CO_3主要表现在焦油的二次裂解与蒸汽重整反应上。从经济成本与催化效果角度综合考量,牛粪灰催化湿牛粪热解制取富氢气体具有良好的实际应用价值。     

酸处理化学污泥溶出铝盐影响因素研究

用铝盐作为水处理絮凝剂所产生的化学污泥往往含有大量的铝，对其综合利用，既能节省资源，又能避免二次污染。pH值是从化学污泥中浸提铝的关键影响因素，铝只有在pH值〈1．7（酸浓度〉0．02mol／L）时才能溶出，当酸浓度增加到4．0mol／L（pH值=0．6）时，铝溶出率最大。在酸性环境中，铝溶出时间很短，一般在4min后就达到了溶解平衡。搅拌与提高温度都能提高铝的溶出率。污泥中含有或向其中加入不同官能团小分子化合物也是铝溶出的强化条件，特别是含有-OH或含-OH与-NH2有机物共存时对铝的增溶效果最明显，一般可增溶10％以上，并可使铝溶出的pH值〈1．7的上限延伸到3．0左右。     

硅碳素再生除锰效果试验研究

对硅碳素（ANJ．SIC）的再生及再生后去除水中Mn^2＋的效果进行试验研究。试验表明,用NaOH再生后的硅碳素（ANJ．SIC）与再生前相比,出水Mn^2＋浓度达到0．1mg／L以下的时间有所延长。当原水Mn^2＋浓度范围为2．162～2．24mg／L、流速为10．4m／h时,再生后硅碳素（ANJ．SIC）出水Mn^2＋浓度在0．1mg／L以下的时间比再生前延长了近1倍。对再生率进行了试验研究,得出再生次数与再生率的关系。试验表明,用NaOH再生后再生率在第二次时能达到182．3％,平均再生率为170％。对再生机理进行了深入的分析研究;     

鸡粪与NaOH预处理麦秸联合厌氧发酵产气性能与协同效果研究

试验研究了不同负荷下不同混合比例的鸡粪与NaOH预处理麦秸的厌氧发酵产气性能和协同作用效果。以鸡粪和2%NaOH预处理后的麦秸作为发酵原料,研究了混合物料在3种负荷和9种混合比例条件下的厌氧发酵产气情况。结果表明:在3种负荷(50,65,80 g/L)中,均是鸡粪和麦秸比例为1∶2时产气效果最佳,其累计产气量分别达到32 000,43 030 mL和50 370 mL;其TS产气率分别达到328.2,356.9,352.8 mL/g,比纯鸡粪相应负荷分别提高了27%,29%,23%。不同比例下,3种负荷中,均是65 g/L时产气效果最好,鸡粪与麦秸的协同作用使累计产气量提高了7%～17.7%。     

Pipeline vs. truck transport of beef cattle manure

Anaerobic digestion (AD) of manure can be conducted at a wide range of capacities. As capacity increases, economies of scale in capital equipment are realized but transportation costs increase as manure must be carried longer distances to the plant site. In this study, we evaluate the cost of pipelining manure from beef cattle feedlots and digestate from an AD plant as an alternative to truck transport. Pipeline transportation cost for manure is minimized at a slurry concentration of about 12%; low concentrations require a larger pipeline, and high concentrations require higher pumping costs. Pipelining costs are highly scale dependent, while trucking costs are virtually independent of scale for a given carrier size. A stand-alone manure pipeline competes with trucking at 90,000 head of beef cattle. Digestate volume is about 2.4 times the volume of manure and a stand-alone digestate pipeline is more economic than trucking at 21,000 head, and a two-way pipeline at 29,000 head. Incremental net fixed costs for trans-shipment from truck to pipeline are low for manure and zero for digestate because equipment installed at the pipeline inlet eliminates the need for identical equipment within the digester plant. A manure pipeline must run for a minimum distance to recover the incremental fixed cost of trans-shipment; at 300,000 animals, the minimum economic pipeline distance is 9 km. Pipeline transport of beef cattle manure has the potential to reduce overall transportation cost to a large centralized digester in areas such as Dodge City, Kansas or Lethbridge, Alberta where very large numbers of beef cattle are in feedlots. A 50 km pipeline carrying manure from 300,000 beef cattle has an overall transport cost of 40% of ongoing truck transport.     

Effects on the biogas and methane production of cattle manure treated with urease inhibitor

Urease inhibitors are in general known as potential measure for reducing ammonia emissions in dairy and cattle housing systems. Due to the application of the urease inhibitor on the exercise areas within a housing system the inhibitor is “mixed” with cattle manure and this “mixture” remains unchanged during manure storage. In Germany, a large part of the total stored cattle manure is utilized as a substrate in biogas plants. Therefore, the aim of the current study was to test if different concentrations of urease inhibitor mixed with typical cattle slurry will have any (negative) effects on the biogas and methane yield. The Hohenheim Biogas Yield Test (HBT) was used to determine if the biogas and methane production of cattle manure is influenced by the admixture with urease inhibitor. Altogether, four urease inhibitor concentrations (0%, 0.1%, 1% und 10% of total Kjeldahl nitrogen) were tested in the HBT experiments with two different substrates, cattle manure and cellulose, as a reference, in repetitions each. The average biogas and methane production of cellulose was 740 L_N/kg_ODM and 403 L_N/kg _ODM and of cattle manure 471 L_N/kg_ODM and 295 L_N/kg_ODM. Both substrates treated with urease inhibitor showed no significant change in the biogas and methane production compared to the untreated ones. The use of urease inhibitors to reduce ammonia is harmless from the view of biogas plants.     

Harnessing methane generated from livestock manure in Ghana, Nigeria, Mali and Burkina Faso

Methane emission from livestock manure is increasingly contributing to the global green house gas emissions. In this paper the methane emission from cattle, pig, sheep, goat and chicken manure in four West African countries; Nigeria, Ghana, Burkina Faso and Mali were estimated. A systematic estimation of the methane emission was done based on the livestock production projections by FAO from 1998 to 2008 and guidelines provided by the Intergovernmental Panel on Climate Change (IPCC). During this period, cattle were found to have emitted more methane followed by pigs, goats, sheep and chicken in that order. A total of about 845 Gg of methane was emitted by the livestock during the period of which cattle contributed about 40%, whereas pigs, goats, sheep and chicken contributed 21.2%, 18.7%, 13.1% and 6.6% respectively. The methane emission from manure management in these countries increased from 64.1 Gg in 1998 to 90.5 Gg in 2008, with an annual growth rate of 3.4% y⁻¹. The methane estimated from livestock manure over the period was shown to be consistent with the linear group model which predicts that in 2018, 2.4 Mt CO₂-eq will be emitted increasing to 3.0 Mt CO₂-eq in 2028 if the mechanism of manure management remains unchanged. This paper reveals that generating methane from the manure produced by the livestock under controlled conditions could supplement the energy needs, increase Gross Domestic Product (GDP) and consequently reduce the direct impact of methane on climate change.     

Characterization of corn stover, distiller grains and cattle manure for thermochemical conversion

Corn stover, distiller grains and cattle manure were characterized to evaluate their acceptability for thermochemical conversion. The energy densities of ground corn stover, distiller grains and cattle manure after totally drying were 3402, 11,813 and 10,374 MJ/m³, compared to 37,125 MJ/m³ for coal. The contents of volatiles in corn stover, distiller grains and cattle manure were 77.4, 82.6 and 82.8%, respectively, on a dry and ash-free basis compared to 43.6% for coal. About 90% of the volatiles in corn stover, distiller grains and cattle manure were released at pyrolysis temperatures of 497, 573 and 565 °C, respectively. The combustion of corn stover, distiller grains and cattle manure were completed at 620, 840 and 560 °C, respectively. The heat values of the biomass and air mixture for stoichiometric combustion were 2.64, 2.75 and 1.77 MJ/kg for dried corn stover, distiller grains and cattle manure, respectively, as compared to 2.69 MJ/kg for coal. Combustion of 1 kg of dry corn stover, distiller grains and cattle manure generated 5.33, 6.20 and 5.66 Nm³ of flue gas, respectively, compared to 8.34 Nm³ for coal. Simulation showed that gasification of 1 kg of dried corn stover, distiller grains and cattle manure at 850 °C and ER of 0.3 generated 2.02, 2.37 and 1.44 Nm³ dry syngas at a heating value of about 4.5 MJ/Nm³, compared to 3.52 Nm³ at 5.8 MJ/Nm³ for coal. The molecular ratio of H₂ to CO in the biomass-derived syngas was close to 1.0, compared to about 0.5 for the coal-derived syngas.     

Green biohydrogen production in a Co-digestion process from mixture of high carbohydrate food waste and cattle/chicken manure digestate

This study was investigated biohydrogen production on the effects of different ratio of food waste to seed digestate and pH value from co-digestion process in anaerobic reactor. The seed digestate was mixture of cattle manure 45%, corn silage 25%, chicken manure 15%, and olive pomace 15% which was collected from the biogas plant in central Italy. It was found that the peaks of total biogas and the biohydrogen productions were 1355 ± 26 and 436 ± 10 mL whereas the biohydrogen yield was 50.4 mL/g-VS (45.8 mL/g-COD) with 43.33% COD removal rate, the bacteria to substrate volatile solids (VS) ratio was 2:1 where seed digestate to food waste was 6:4 under pH 6.5. As a consequence, food waste with a high COD concentration can be adapted C/N ratio by the cattle manure and chicken manure in the seed digestate which resulted in a high biohydrogen production. The food waste co-digestion system mixed with biogas plant digestate is one of approach to increase total biogas production.     

The impact of inoculum source,inoculum to substrate ratio and sample preservation on methane potential from different substrates

Batch experiments were conducted to evaluate the impact of inoculum sources, inoculum to substrate (IS) ratio and storage conditions on the potential and production rate of methane (CH₄) from different substrates: wheat straw, whole crop maize, cattle manure, grass and cellulose.The results of the test with four inocula and four substrates indicated that inoculum source could have a significant impact on both CH₄ potential (BMP) and the kinetics parameters of different substrates. The two inocula showing the highest BMP and production rates in each period were those coming from a feeding with more than 70% of animal manure under thermophilic conditions. The impact of the IS ratio in the range 0.25–2.5, in terms of g volatile solids (VS) substrate/g VS inoculum, depended on substrate type. Maize silage was more affected to changes in the IS ratio than wheat straw. The optimal IS ratio range for maize was 1.0–1.5, however, a wider IS range can be used in wheat straw (0.5–2.5). The impact of freezing and drying depended on biomass type. Freezing, drying and ensiling of grass increased the CH₄ yield compared to fresh grass. Drying of maize had no impact while freezing reduced the CH₄ potential. Drying and freezing had no impact on straw.     

Grass as a high potential by-product: Buffalo grass to biogas and the increase of system performance and stability

Buffalo grass and alkaline-pretreated buffalo grass samples were co-digested with cow manure separately to generate biogas in anaerobic reactors. The study considered a solid content of 20% (10% buffalo grass and 10% cow manure). The methane (CH₄) content and CH₄ yield of the distinct experiments were compared. For the untreated buffalo grass, the weighed buffalo grass was mixed with cow manure and water. For the alkaline-pretreated buffalo grass, the weighed buffalo grass was soaked in 1% sodium hydroxide for 1 day prior to being mixed with cow manure and water. The untreated and pretreated buffalo grass-manure were fed semi-continuously at the rate of 125 mL/day for five days feeding in a 5 L reactor, with 40 days hydraulic retention time. The experiments were conducted for approximately 100 days. Results were reported when the systems were in steady-state conditions. The chemical oxygen demand (COD) conversion efficiency of co-digestion of the untreated and pretreated buffalo grass-manure were 46.21 and 62.76%, respectively, and for the total volatile solids (TVS) were 68.50 and 71.80%, respectively. The CH₄ contents generated from co-digestion of the untreated and pretreated buffalo grass-manure were 48.32% and 50.36%, respectively. The CH₄ yields generated from co-digestion of the untreated and pretreated buffalo grass-manure were 328 and 385 L/kgTVS conversion, respectively. It was observed from the experiments that pretreatment of the buffalo grass prior to co-digestion provided system stability during biogas production.     

Anaerobic co-digestion of chicken and cattle manures: Free ammonia inhibition

In this study, 4 different anaerobic digesters were set by keeping the chicken manure ratios as 0%, 30%, 70%, and 100% by completing the remaining portions with cattle manures. According to the results, the highest methane production potentials were 144 ± 7, 201 ± 12, 217 ± 3, 256 ± 5 L/kg VS_added, respectively. After reaching the highest total nitrogen concentrations in semi continuously operated reactors, methane level has dropped due to free ammonia (as high as 652 mg NH₃-N/L) inhibition stimulated by high pH in all reactors. Recovery of the methane production following free ammonia inhibition was greatly succeeded although deficiency in essential trace elements such as Cd and Ni. Nevertheless, it was shown that cattle manure alone can be a good co-substrate for the chicken manure.     

Effects of algal hydrolyzate as reaction medium on enzymatic hydrolysis of lignocelluloses

Effects of an algal hydrolyzate on the enzymatic hydrolysis of lignocelluloses were examined using four bioenergy feedstocks (poplar, corn stover, switchgrass, and anaerobically digested manure fiber). Feedstocks were pretreated using dilute acid or alkali prior to hydrolysis. Hydrolysis reactions were conducted using the neutralized algal hydrolyzate, citrate buffer, or deioinized water as reaction media. Results demonstrated that algal hydrolyzate significantly improved the efficiency of enzymatic hydrolysis of lignin-rich or structurally recalcitrant biomass such as poplar and anaerobically digested manure fiber. This study showed that algal biomass can be used as not only a biofuel feedstock for direct diesel and ethanol production, but also a supplemental feedstock to enhance the performance of lignocellulosic biorefining.