research_proposal_范本.doc

AA大学“国家建设高水平大学公派研究生项目”研修计划Research Plan for CSC Scholarship Program, AA姓名/NameXxxxxxxxx学号/Student IDxxxxxx性别/GenderMale出生年月日/Date of birthXxxxxxxx所在学院/CollegeXxxxxxxxxxx所学专业/MajorXxxxxxxxxx国内导师/Domestic supervisor Xxxxxxxx留学国别/Hosting foreign country Xxxxx留学院校/Hosting foreign institution Xxxxxxxx留学院系/Hosting faculty or department Xxxxxxxxx国外导师/Hosting foreign supervisor Xxxxxx学习期限/Duration of study xxx months (from xxxxx to xxxxx) 研究课题名称 Research Title:Minimization of energy requirement for producing solid fuel from sewage sludge employing hydrothermal treatment科研课题背景介绍Research Background:In China, over 1.58107 tons of dewatered sewage sludge, with 80% water content, was generated from wastewater treatment plant in 2008. About 60% of the organic substances, removed during the wastewater treatment process, become concentrated as sludge. Traditional disposal methods used by municipal solid waste treatment facilities, including landfills, composting, and incineration, are unsuitable for sludge disposal because of its high moisture content. Few proper sludge treatments or disposal methods are currently applied in China. The treatment and disposal of sewage sludge are significant environmental problems and have therefore become a major focus of current environmental protection policies. Sludge incineration has received worldwide attention as an effective approach to reduce the quantity and toxicity of sludge. In Japan, most of burnable wastes are incinerated. However, direct sludge incineration is not cost-efficient and creates unstable burning which generates large amounts of gaseous pollutants. Currently, bio-energy is an excellent energy recycling technology with bright prospect, given its ability to turn refuse into energy. As such, in recent years refuse-derived fuel (RDF) technology has become a refuse processing technology adopted by advanced nations in Europe, America, and Japan etc. In China, sewage sludge was mixed with auxiliary fuels, sulfur-fixating agents, and preservatives. The blends were granulated generating sludge-derived fuel (traditional SDF, T-SDF). Most researchers focused mainly on the T-SDF technology and have made important contribution to understand the combustion characteristics of T-SDF. However, all these technologies relied mainly on adding a large number of coals (about 50%) to improve the heat value and lower the moisture content of fuels. The heat value of T-SDF depends merely on the quantity and proportion of auxiliary fuels, not the reduction of water content of sludge. In some extent, this process realizes sludge recycling and harmless treatment. However, the volume and weight of T-SDF are also increased, resulting in increase of operating cost. Moreover, the small proportion (about 40%) of sludge in the T-SDF leads to a lower capacity that cannot meet the needs of sludge treatment. Therefore, it is urgent for us to find a cost-effective and energy-saving way to realize sludge recycling, harmless treatment and reduction.The core issue to produce solid fuel from sewage sludge is how to efficiently remove the water from sludge. The object of this project is to minimize the energy requirements for producing cost-effective and applicable solid fuel from sewage sludge. Hydrothermal treatment (or thermal hydrolysis) is a process in which the sludge is heated as an aqueous phase to temperatures (normally) varying between 120 and about 400C. The hydrothermal treatment process aims to disintegrate the sludge and result in a formation and accumulation of dissolved products. This makes it possible to recover and recycle useful resources from the sludge, such as volatile fatty acids, phosphorous compounds, organic compounds for enhanced anaerobic biogas production, and coagulants. After hydrothermal treatment, the sludge and other waste biomass can be dehydrated by mechanical methods and dried under natural circumstances easily, used as substituted fuel which we called it novel sludge-derived fuel (N-SDF) in this research. His research will study the influence of hydrothermal conditions on natural drying characteristics of sewage sludge and other waste biomass, the drying mechanisms of hydrothermal treatment sludge and waste biomass. This research will not only drive the development of sludge treatment technologies but also lend a hand to other waste biomass treatment.In previous studies, we found that the N-SDF produced from sewage sludge by employing the hydrothermal treatment is easier when drying under natural circumstances. After 24h natural drying, about 50% water was removed. Comparing with raw sludge, the drying is faster. Obviously, the heat value of N-SDF can be improved further, which increase the stability of combustion. However, some factors are still unclear and needed to be studied further, limiting its popularization and applications. Therefore, it is necessary to conduct this research. xxxxxxxx is developing and commercializing total technologies to convert unutilized resources such as solid wastes and biomass into high value added energy resources (solid fuel, gaseous fuel, liquid fuel and electric power) by combining various technologies which have been jointly developed with many companies. We have done many work and made some progress in the field of Waste-to-Energy in xxxxxxx. Because of our outstanding contributions to the development of waste-to-energy technologies, With the co-advising of Prof. xxx and I, this project can be finished on time.References:Wang, W., Luo, Y.X., Qiao, W. 2010. Possible Solutions for sludge dewatering in China. Front. Environ. Sci. Engin. China, 1:102-107. Doi: 10.1007/s11783-010-001-z. Jiang, J.G., Du, X.J., Yang, S.H. 2010. Analysis of the combustion of sewage sludge-derived fuel by a thermogravimetric method in China. Waste Management, 30: 1407-1413.Chen, W.S., Chang, F.C., Shen Y.H., Tsai, M.S. 2010. The characteristics of organic sludge/sawdust derived fuel, Bioresource Technology, doi: 10.1016/j.biortech.2010.11.007.Jiang, Z.L., Meng, D.W., Mu, H.Y., Yoshikawa. K. 2010. Study on the hydrothermal drying technology of sewage sludge. SCIENCE CHINA Technological Sciences, 1:160-163. doi: 10.1007/s11431-009-0423-7.Neyens, E., Baeyens, J. 2003. A review of thermal sludge pre-treatment process to improve dewaterability. Journal of Hazardous Materials B, 98:51-67.Yoshikawa. K. 2009. Hydrothermal Treatment of Municipal Solid Waste to Produce Solid Fuel. 7th International Energy Conversion Engineering Conference, Aug 2009, Denver, Colorado.Namioka. T., Morohashi. Y., Yamane. R., Yoshikawa. K. 2009. Hydrothermal Treatment of Dewatered Sewage Sludge for Fuel Production. Journal of Environment and Engineering, 1:68-77.Namioka. T., Yoshikawa. K. 2005. Innovative Pretreatment Technology for Wet Biomass Utilizing Middle Pressure Stream. Nihon Kikai Gakkai Nenji Taikai Koen Ronbunshu.3:259-260.Morohashi. Y., Yamane. R., Namioka. T., Yoshikawa. K. 2008. A Study on Improvement of Dehydration Performance of Sewage Sludge by the Hydrothermal Treatment. Transactions of the Japan Society of Mechanical Engineers Part B. 744:1814-1820.Morohashi. Y., Yamane. R., Yoshikawa. K. High Efficiency Dehydration of Sewage Sludge by the Hydrothermal Treatment and the Press Filter, 26th Annual International Conference on IT3, May 14-18, 2007, Phoenix, AZ. Zhao, P.T., Ge, S.F., Chen, Z.Q. 2011. A Study on the Improvement of Sludge Dewaterability by Thermal Conditioning. ICEICE. Wuhan. Accepted. 申请人国内科研准备工作概述Theoretical Review: Inrecent two years,his main work is related to sludge recycling, and thats his interest. He has done some related research in sludge recycling. In the project of sludge drying and incineration, he used a rotary dryer to dry sludge, and then the semi-dry sludge with 40% moisture content was incinerated in coal-fired boiler. To overcome the defects of wedge-shaped paddle dryer in sewage sludge drying, we designed the horizontal disc rotary dryer and did some research on the characteristics of viscous zone of sludge drying. The sewage sludge drying process could be divided into three stages: paste, viscous, and granular. In viscous stage, the moisture content of sludge is about 55%. To study the mechanism of sludge dewatering, the main parameters SRF characterizing sludge dewaterability were experimentally investigated and a paper has been accepted by Journal of Southwest University (Natural Science Edition). The sludge flocculation process was studied through fractal dimensions which were determined by image analysis. Two-dimensional fractal dimensions Df and one-dimensional fractal dimensions D1 of flocs formed at different flocculation time and the filtrate speed and specific resistance to filtrate (SRF) of conditioned sludge were determined to assess sludge dewaterability. Based on the change of fractal dimensions, the sludge flocculation process was divided into three stages: primary particles form flocculi; flocculi collide with each other, group together to form flocs; equilibrium stage. The critical watershed flocculation times are 45s and 150s respectively. At the very end of flocculi stage and the beginning of flocs, the time is generally set as 45s and when a subsequent dewatering step is applied, lower moisture content sludge cake would be obtained. These researches will provide a theoretical basis for this application.We used the saturated steam to conditioning sewage sludge and applied the steam explosion to crush the cell walls and transform bond water into free water for improving sludge dewaterability. A pilot scale experimental device has been built and operated in Yangzhong, Jiangsu province, in September 2010. He has also done some lab scale experimental study on sludge thermal conditioning. He investigated the factors affecting sludge dewaterability by thermal conditioning experimentally, and found that the major factors for improving sludge dewaterability by thermal conditioning are conditioning temperature and residence time. He also found that the optimal temperature and residence time for treating municipal sludge are 180C and 60mins, respectively. The moisture content of sludge cake is 50.88% after pressure filtration for 50 minutes. Thermal conditioning transforms organic compounds of sludge into soluble substances and greatly increases the COD of the separated water. After thermal conditioning at 180C, the COD of the separated water is about 420 times of the original sludge. Thermal sludge conditioning has the advantage of low energy consumption and can help us achieve the goals of sludge reduction, harmlessness and efficient utilization. He used dewatered sludge (20% DS), leaves and straw (unbroken) as raw materials, applied the hydrothermal and hydrothermal treatment/steam explosion to produce sludge derived fuel. The biomass (leaves, straw etc.) is not pre-broken. The final product is almost odorless, and the heat value of dry solids didnt change after hydrothermal treatment. The process integrates advanced sludge dewatering and sludge derived fuel together and is easier to implement. Compared with T-SDF technologies, this process incorporates the advantages of advanced sludge dewatering and sludge derived fuel. The heat value of N-SDF depends mainly on the water removal of sludge not the adding of auxiliary fuel, the proportion of sludge can be highly increased. The production cost of fuel is reduced because sludge drying and auxiliary fuel are no longer required. With a moisture content of 60%, the low heat value of the fuel is 8500 KJ/kg and can be easily burned in a coal-fired boiler. These researches provide a basis for an experimental study of the application.He is very interested in what he has done and what he will do. With the co-advising of Prof. Yoshikawa, Prof.Ge and I, I am sure he can finish this project on time and make a progress in his research. 出国学习预期目标The Goals Of The Research: (1) To learn some energy conversion technologies, especially waste-to-energy technologies. (2) To study sludge recycling technologies systematically, and do some research on minimization of energy requirement for producing solid fuel according to Prof. Yoshikawas lab facilities, find an efficient method suitable for Chinas national conditions to realize waste-to-energy. (3) To evaluate and characterize the performances of N-SDF, using life-cycle assessment (LCA) to access the economic feasibility of solid fuel produced from sewage sludge and some other waste biomass. 科研方法The Experimental Methods: (1) Mechanisms of Hydrothermal Treatment Improving N-SDF Drying Properties:The influence of hydrothermal conditions (Temperature, Pressure, and Residence Time) on particle Size Distribution: The moisture content of the dewatered sludge would be determined first and then some certain sludge will be placed in the reactor (MMJ-500, OMLAB-TECH CO., LTD., Tochigi, Japan). Three main parameters-(1) Pressure (1.2-2.6Mpa), (2) residence time (10-90 min), (3) Temperature (120-250C) are varied to understand the characteristics of hydrothermal-treatment sludge. After hydrothermal-treatment for a certain time, 5 samples formed under different hydrothermal conditions will be diluted 100 times with distilled water. Particle size distribution (PSD) was determined by particle measuring systems two-sensor particle counting system, which allows a user to measure particles in most liquids quickly and efficiently within the range of 0.2125.0m. The particle 10 counter provides up to 30 user-selectable sizing channels, allowing a very complete analysis of the particle size distribution and simultaneous measurement of various quality assurance standards. The Particle Measuring system incorporates two LiQuilaz volumetric particle counters combined with the LS200 Syringe Sampler. The two LiQuilaz particle counters detect particles suspended in liquid between 0.2 and 125.0m. The first particle counter that samples the liquid is a LiQuilaz S02, which measures particles ranging from 0.2 to 2.0m. The second particle counter, the LiQuilaz E20P, detects particulates ranging from 2.0 to 125.0m. By combining these two particle counters, the user has up to 30 user-selectable channels for collecting information on the samples. After then, the N-SDF will be dried in an electric oven at 378k until the mass difference reached less than 0.5%. Ultimate analyses will be conducted with an elemental analyzer (PerkinElmer, 2400 Series II CHNS/O System), and the heat values will be measured with a calorimeter (Shimadzu, CA-4PJ).Data Analysis: Although the use of arithmetic-mass mean has been identified more properly to provide a wide scale for differentiate mean sizes of different PSD; this study will use the geometric-mass mean particle size. Natural Drying Characteristics of N-SDF: To study on the natural drying characteristics of N-SDF, the dewatered sludge will be first dehydrated by a cylinder pressure dewatering device to form a reference sample. And then 5 samples formed under different hydrothermal conditions and the reference sample will be dried 24h under natural circumstances. The weight of these samples at different drying time will be recorded to calculate the drying speed used to access N-SDF drying properties.Inner Structure of N-SDF: The dewatered sludge and hydrothermal treatment sludge will be pressed by a cylinder pressure dewatering device firstly and then dried under natural conditions until the mass difference reached less than 0.5%. The changes of materials surfaces will be recorded by a CCD camera equipped with a microscope. These images will be analyzed by computer software (Image Pro-Plus) to calculate the porosity of the materials surfaces. The dried N-SDF will be broken to measure the BET specific surface area and inner porosity.Water distribution in N-SDF: The total water content was determined by drying at 105 C until a constant weight was reached. The bound water content was measured using the dilatometric method. It is based on the assumption that free water freezes at temperatures near the freezing point of pure water whereas bound water does not freeze even at temperatures as low as -20C. The volume expansion observed when cooling sludge to temperatures down to -20C is therefore solely due to the waterice transformation of the free water. Its measurement allows the determination of both the free water content and the bound water content of the sample knowing its total water content. Volume expansion measurements were performed using xylene as an indicator fluid between room temperature and -12.5 C. It was checked that no further volume variation due to the water transformation occurred for temperatures down to -20C.(2) Combustion/ Co-combustion Characteristics of N-SDF:Combustion Characteristics of N-SDF: The samples were first dried in an oven under 105C. The ratio of the weight loss between the mass weights is the water content. Then the dried samples will be sealed in the crucible and heated in the muffle under 600C for 2h. The weight loss is the volatile matter. The samples will be put in the muffle under 800C in an oxidizing atmosphere for 2h, and the residues are the ashes. The fixed carbon can be calculated by 1 - the volatiles content and the ash content. Thermogravimetric analysis could be done with a thermogravimetric analyzer. Several granules would be randomly picked, dried, ground into powder and screened through 80 mesh screen. Around 10 mg of each sample will be then analyzed in the thermogravimetric analyzer with a heating rate of 10C /min from ambient to 700C under an air flow of 150 mL/min. Perkin-Elmer 2400 Series II CHN organic element analyzer will be used to ultimate analysis of these fuels. Co-Combustion Characteristics of N-SDF and coal: Thermogravimetric tests will be pe