沼液对甜玉米幼苗素质、产量和品质影响的试验研究

试验研究了沼液浸种、沼液喷施和沼液追肥对甜玉米幼苗素质、产量及品质的影响。结果表明．沼液浸种能增强甜玉米的幼苗素质,根鲜重和干重分别比干播增加13．92％和15．71％,全株鲜重和干重分别比干播增加14．81％和6．37％。处理2（沼液浸种）和处理3（沼液喷施）分别比处理1（对照）增产5．37％,11．75％。沼液处理改善了甜玉米的内在品质,处理4（沼液浸种＋沼液追肥＋沼液喷施）的糖／酸和固／酸最大,分别比处理1（对照）增加74．0％,52．7％。沼液处理的籽粒中的钙和铁含量降低,磷、镁和锰含量升高;沼液浸种可促进籽粒对大多数元素的吸收。     

沼液对土壤有机质含量和肥效的影响

试验研究了施用沼液对土壤改良及土壤有机质含量和肥效的影响.试验分为8个组,每组设4个重复;土壤处理分为灭菌和不灭菌2部分;青菜种植分为施用沼液与不施用沼液2部分.试验结果表明:施用沼液能够显著增加土壤有机质、氨态氮、速效钾、速效磷的含量,有利于调节土壤pH值.施用沼液对土壤有显著的改良效果.     

生物质鼓泡流化床气化特性的空气当量比影响分析

在鼓泡流化床生物质气化器内,以空气为气化介质,对木屑进行了常压气化试验研究。选择空气当量比ER为0．13～0．33进行试验,研究了在气化温度为760％、810～12和860℃条件下对气化结果的影响。试验结果表明：主要燃气成分含量H2：6．2％～14．1％,CO29．9％～30．2％,CH4：1．6％～11．2％,产气率：1．0m3／kg～1．740／kg,产气低位热值：3526kJ／m3～9184kJ／m3,碳转换率：52．3％～82．3％,气化效率38％～69．1％。     

沼液喂猪经济效益好

据资料介绍,用沼液作饲料添加剂喂的猪,生猪食欲旺盛、增重速度快、毛稀色美、贪睡,抗病力强。通过对比试验,平均日增重比不用沼液增加百分之五十,每头猪减少精饲料100公斤,出栏周期缩短二个月,料肉比提高到3.5:1。     

沼肥对保护地番茄生长发育及其产量的影响

采用二裂式区组设计的方法,以番茄为供试作物,以沼肥（沼液、沼渣）、猪粪和化肥为肥料,研究了不同施肥措施对番茄生长发育及其产量的影响。结果表明：与施用化肥相比,施用沼液的番茄植株平均株高及根系体积有所增加,番茄产量略有降低;与施用猪粪相比,施用沼渣可促进植株茎秆的健壮生长及根系发育,番茄产量提高20．8％;与沼渣和化肥配合施用相比,沼渣与沼液配合施用促进了番茄植株的生长发育,其植株生长稳健,根系发达,而且番茄产量增加;与猪粪和化肥配合施用相比,猪粪与沼液配合施用促进了番茄植株的生长发育,其株高较高、茎秆粗壮、根系发达,但番茄产量下降。     

热风炉用高效能陶瓷燃烧器的开发

介绍了一类高效能陶瓷燃烧器，其试验结果为：（1）空，煤气通道联吹的阻力系数分别为4．8－5．0和1．8－2．0；（2）煤气通道的配气均匀度达到了92．46％，比未采用煤气导流装置时提高了11．33个百分点，比套筒式陶瓷燃烧器提高了6．49个百分点；（3）一，二次风出口配气均匀度达到了90．66％，和94．57％，实践证明，采用高效能陶瓷燃烧器是提高热风炉送风温度的有效途径之一。     

2010年前3季度山西煤炭产量逼近内蒙古

国家能源局权威人士透露,2010年1～9月,内蒙古生产原煤5．47×10^8t,比去年同期增加0．91×10^8t,增长19．8％。由于区内煤炭市场供需基本平稳,价格变化不大。其中,出区煤炭3．35×10^8t,占总销量的61％,比去年同期增加0．82×10^8t,增长34．5％。铁路运送煤炭出区量为2．85×10^8t,比去年同期增加0．65×10^8t,增长30．1％;     

2006年全国污染物排放总量公布

近日，国家环保总局公布，2006年全国二氧化硫排放量和化学需氧量分别比2005年增长1．8％和1．2％。与上一年度相比，增幅分别回落了11．3和4．4个百分点。     

喷油脉宽对电控汽油机燃用M85甲醇汽油的影响

为了在电控汽油机上优化M85甲醇汽油的应用,利用发动机台架试验,分析了电控汽油机直接燃用M85的主要问题,并通过放大喷油脉宽,增加M85甲醇汽油的喷油量来改善发动机性能。试验结果表明：与燃用汽油相比,喷油脉宽放大1．3倍时,发动机燃用M85甲醇汽油的功率和扭矩分别平均降低了6．83％和7．15％;小时燃油消耗量与有效燃油消耗率增大,但有效能耗平均降低6％;CO和HC排放分别平均降低11．28％和0．64％;NOx排放平均增加55．56％。     

2006年全国污染物排放总量公布

近日，国家环保总局公布，2006年全国二氧化硫排放量和化学需氧量分别比2005年增长1．8％和1．2％。与上一年度相比，增幅分别回落了11．3和4．4个百分点。     

Influence of chemical nature of organic wastes on their conversion to hydrogen by heat-shock digested sludge

The influence of the chemical nature of high-solid organic wastes (HSOW) on their biohydrogen generation was investigated using simulated high-solid bioreactors under mesophilic conditions. The bioreactors were filled with 10% total solid of rice, potato, fat meat, chicken skin, egg, and lean meat. Experimental results indicate that hydrogen-producing potential of carbohydrate-rich HSOW (rice and potato) was approximately 20 times larger than that of fat-rich HSOW (fat meat and chicken skin) and of protein-rich HSOW (egg and lean meat). According to development trends of pH and hydrogen, pH around 6.0 might be threshold for heat-shock digested sludge; that is Clostridium-rich sludge, converting fat- and protein-rich HSOW to hydrogen; but pH threshold for Clostridium-rich sludge consuming carbohydrates-rich HSOW occurred at around 5.0. In bulk solution, volatile fatty acids (VFA) and alcohols occurred concurrently and the trends of carbohydrate-rich HSOW were similar to those of protein-rich HSOW. Considering developments of carbohydrates and VFAs together with that of hydrogen one infers that lipids would be hydrolyzed to carbohydrates and the carbon flow would proceed through acetate/H₂+CO₂ cleavage. Indications from cluster analysis of pH development trends are that a cometabolism would be obtained in wastes rich in carbohydrate and protein.     

Effects of EGR on performance of engines with spark gap projection and fueled by biogas–hydrogen blends

In this study, the effects of exhaust gas recirculation (EGR) on the behavior of a spark ignition engine fueled by hydrogen-blended low-calorific biogas were investigated, and its performance and emission characteristics were compared with those of the lean burn engine investigated in our previous work. The engine was operated at a constant rotational speed of 1800 rpm under a 60 kW power output condition, and a simulated biogas containing H₂ was used to realize a wide range of gas compositions. The engine test results demonstrate that when less than 20% H₂ was added to the biogas, the EGR operations had inferior fuel economy to the lean burn technique. However, when the H₂ blending ratio was increased, the EGR method achieved higher engine performance with lower NO_x emissions than the legal standard. Analyses of the O₂ fraction and thermal capacity variations of the inlet charge also indicated that a dilution (O₂ replacement) effect rather than a thermal effect was the dominant factor when EGR was introduced in a low-calorific biogas engine. Subsequently, in order to improve the engine efficiency as well as combustion characteristics, the spark gap was projected further into the combustion chamber with EGR engine operations. The engine test results show that repositioning the discharge location improved the thermal efficiency, and the maximum tolerable EGR rate increased because of spatial advantages such as relatively short flame propagation lengths and high electrode temperatures.     

Anaerobic fermentation technology increases biomass energy use efficiency in crop residue utilization and biogas production

A biomass energy utilization project (Corn stalk→Cattle→Cattle dung→Biogas digester→Biogas/Digester residues→Soil) was conducted in a typical temperate agro-village of China from 2005 to 2010. The present study focused on two key approaches of the ecological loop: (1) increasing corn stalk use efficiency by improving anaerobic fermentation technology; and (2) enhancing biogas productivity by optimizing fermentation conditions. Our results showed that crude protein and fat of corn stalks significantly increased, while crude fiber content and pH decreased considerably during anaerobic fermentation. The cattle digestion rate, forage consumption and increases in cattle weight were higher in cattle fed fermented corn stalks than in those fed non-fermented corn stalks. The rate of biogas production was higher (78.4%) by using cattle dung as a substrate than using crop residues. Heat preservation measures effectively enhanced the biogas production rate (12.3%). In 2005, only two cattle were fed in this village, with only 1.1% corn stalk utilized as forage. No more than three biogas digesters existed, and the proportion of biogas energy used in total household fuel was only 1.7%. At the end of the 5-year experiment, the number of cattle capita reached 169 with 78.9% corn stalk used as forage. Biogas digesters increased to 130, and the proportion of biogas energy used in total household fuel was up to 42.3%. A significant positive correlation was noted between the increasing rate of farmers’ incomes and the proportion of corn stalks used as forage. Available nutrients were higher in fermented cattle dung than in fresh cattle dung. Our findings clearly suggest that anaerobic fermentation technology is important in enhancing crop residue use efficiency, biogas productivity and soil fertility. Fermentation technology may help reduce the use of fossil fuels and improve the environment in rural areas.     

Changing old habits: The case of feeding patterns in anaerobic digesters

A non-linear programming model was developed to maximize the economic profit from an anaerobic co-digester. The model consists of a combination of technical and economic equations, linked through the biogas production variable. Five scenarios were simulated. These differed with regard to substrate inlet mass flow rate, organic loading rate and hydraulic retention time. The impact on biogas production was investigated and an economic analysis was undertaken based on the concepts of profitability and Net Present Value. The model results indicate that varying the substrate inlet mass flow rate and organic loading rate could have a positive impact on the profitability of co-digesters in Flanders. This can be achieved either by increasing the interval time between feedstock input, or by feeding individual streams of feedstock separately into the system, while at the same time reducing the hydraulic retention time.     

Experimental and computational study on the enhancement of engine characteristics by hydrogen enrichment in a biogas fuelled spark ignition engine

Limitations on the upgradation of biogas to biomethane in terms of cost effectiveness and technology maturity levels for stationary power generation purpose in rural applications have redirected the research focus towards possibilities for enhancement of biogas fuel quality by blending with superior quality fuels. In this work, the effect of hydrogen enrichment on performance, combustion and emission characteristics of a single-cylinder, four-stroke, water-cooled, biogas fuelled spark-ignition engine operated at the compression ratio of 10:1 and 1500 rpm has been evaluated using experimental and computational (CFD) studies. The percentage share of hydrogen in the inducted biogas fuel mixture was increased from 0 to 30%, and engine characteristics with pure methane fuel was considered as a baseline for comparative analysis. The CFD model is developed in Converge CFD software for a better understanding on combustion phenomenon and is validated with experimental data. In addition, the percentage share of hydrogen enrichment which would serve as a compromise between biogas upgradation cost and engine characteristics is also identified. The results of study indicated an enhancement in combustion characteristics (peak in-cylinder pressure increased; COV_IMEP reduced from 9.87% to 1.66%; flame initiation and combustion durations reduced) and emission characteristics (hydrocarbon emissions reduced, and NOx emissions increased but still lower than pure methane) with increase in hydrogen share from 0 to 30% in biogas fuelled SI engine. Flame propagation speed increased and combustion duration reduced with hydrogen supplementation and the same was evident from the results of the CFD model. Performance of the engine increased with increase in hydrogen share up to 20% and further increment in hydrogen share degraded the performance, owing to heat losses and the enhancement in combustion characteristics were relatively small. Overall, it was found that 20% blending of hydrogen in the inducted biogas fuel mixture will be effective in enhancing the engine characteristics of biogas fuelled engines for stationary power generation applications and it holds a good compromise between biogas upgradation cost and engine performance.     

Performance and emission characteristics of a SI engine fueled by low calorific biogas blended with hydrogen

In this study, an experimental investigation on a naturally aspirated (NA), 8-L spark ignition engine fueled by biogas with various methane concentrations - which we called the N₂ dilution test - was performed in terms of its thermal efficiency, combustion characteristics and emissions. The engine was operated at a constant engine rotational speed of 1800 rpm under a 60 kW power output condition and simulated biogas was employed to realize a wide range of changes in heating value and gas composition. The N₂ dilution test results show that an increase of inert gas in biogas was beneficial to thermal efficiency enhancement and NO_x emission reduction, while exacerbating THC emissions and cyclic variations. Then, as a way to achieve stable combustion for the lowest quality biogas, H₂ addition tests were carried out in various excess air ratios. H₂ fractions ranging from 5 to 30% were blended to the biogas and the effects of hydrogen addition on engine behavior were evaluated. The engine test results indicated that the addition of hydrogen improved in-cylinder combustion characteristics, extending lean operating limit as well as reducing THC emissions while elevating NO_x generation. In terms of efficiency, however, a competition between enhanced combustion stability and increased cooling energy loss was observed with a rise in H₂ concentration, maximizing engine efficiency at 5-10% H₂ concentration. Moreover, based on the peak efficiency operating point, a set of optimum operating conditions for minimum emissions with the least amount of efficiency loss was suggested in terms of excess air ratio, spark ignition timing, and hydrogen addition rate as one of the main results.     

Reduced hydraulic retention times in low-cost tubular digesters: Two issues

Low-cost tubular digesters have been implemented in several developing countries. One of the problems reported from field surveys is that biogas generation that does not meet the user’s expectations. This report provides two reasons for the discrepancy between the biogas generation rate estimated in the design phase and the actual rate measured after construction, due to a lower final hydraulic retention time (HRT). The hydraulic retention time is normally determined from the liquid volume calculated from the cylindrical shape of the bag and not from the trench dimensions. The result is a reduction in HRT of 6%-51%, depending on the dimensions of the trench recommended by various authors. Another factor that is not normally considered is the influence of the biogas pressure on the liquid level inside the digester which negatively affects the liquid volume of the digester, reducing HRT by as much as 15%.     

二价铁离子对糖蜜酒精废水厌氧发酵的影响

提高糖蜜酒精废水的厌氧发酵效率,实现其资源化再利用,本文研究了添加一定量Fe²⁺ 对糖蜜酒精废水厌氧发酵处理过程的影响。结果表明：添加Fe²⁺后发酵液中SO₄²⁻ 的去除率由77.12%提高至90.79%;COD去除率由57.34%提高至81.14%;累积沼气产量由386 mL•g⁻¹ VS提高至475 mL•g⁻¹ VS;产气周期由29天缩短为26天;其氧化还原电位（ORP）升高,pH值降低。     

两种物理吸收法在沼气脱碳中的模拟对比研究

运用化工流程模拟软件PRO/II对水洗法和碳酸丙烯酯法沼气脱碳进行了模拟对比,原料气组分按CH4为57%,CO2为40%,N2为2.8%,O2为0.2%模拟计算,结果显示两种方法在2.7,1.3,0.7 MPa的操作压力下,CH4回收率都可达到98%以上,操作压力极大影响系统运行能耗,宜根据生物天然气终端用途和CO2是否具有回收及利用价值来确定。生物天然气中CH4>93%,CO2<1.5%,N2<5%,O2<0.5%,达到《天然气》二类气及《车用压缩天然气》指标;水洗法CH4和CO2回收率略高于碳酸丙烯酯法,但碳酸丙烯酯法投资低、能耗低、操作维护简单,经济上更有优势。经净化脱碳后的沼气利用价值得到提高,经济和社会效益显著。     

4m3商品化户用玻璃钢沼气池的结构与性能

4m^3商品化户用玻璃钢沼气池为水压式沼气池，最大贮气量为1．1m^3，最大压力100cm水柱，设置进料口水压间和出料口水压间，不设天顶盖，实现自动进出料。该沼气池密封性好，使用寿命可达20a，整池重量轻，仅120kg，建池方便快捷，不受地下水位的影响，发酵启动快，产气率高。