Valorisation of rice husks using a TORBED® combustion process

World production of rice exceeds 750 million tonnes per year of which a fifth is removed in the form of rice husk during the milling process. The use of rice husks as a source of sustainable and renewable energy is often hindered by lack of capital and a poor understanding of rice husk combustion characteristics. This results in the selection of poor quality technology which generates significant quantities of harmful crystalline silica waste. Despite previous work in the area, detailed characterisation of the combustion of rice husk ash in a TORBED reactor across a wide temperature range has not yet been attempted and little effort has been directed towards assessing the economic viability of generating quality rice husk ashes. The use of a TORBED reactor enables low residual carbon after combustion without the generation of harmful crystalline material. Rice husk was combusted in a 400 mm reactor at temperatures between 700 and 950 °C. In the subsequent characterisation studies the resulting materials were shown to be fully amorphous high purity silica (> 95%) and were readily digested in a series of alkaline digestion experiments. Complete silica conversion was only possible using uneconomic Na₂O/SiO₂ ratios and further optimisation of the combustion process to generate higher surface area material is necessary to increase the digestion rates further. Provisional economic analysis suggests that sales of the by-product enhance the returns from rice husk based power generation. TORBED reactors enable the combustion of rice husk with considerable operating flexibility and they generate products that could be used to displace resource intensive products and processes thus, added value from the by-products can be obtained by using TORBED reactor technology

Catalytic applications of waste derived materials

Sustainability has become a watchword and guiding principle for modern society, and with it a growing appreciation that anthropogenic 'waste', in all its manifold forms, can offer a valuable source of energy, construction materials, chemicals and high value functional products. In the context of chemical transformations, waste materials not only provide alternative renewable feedstocks, but also a resource from which to create catalysts. Such waste-derived heterogeneous catalysts serve to improve the overall energy and atom-efficiency of existing and novel chemical processes. This review outlines key chemical transformations for which waste-derived heterogeneous catalysts have been developed, spanning biomass conversion to environmental remediation, and their benefits and disadvantages relative to conventional catalytic technologies

Mathematische Analyse mariner Ökosystemmodelle

This work is concerned with the mathematical formulation of marine ecosystem models. Marine ecosystem models are systems of advection-diffusion-reaction equations. The influence of biogeochemical reactions (e.g. consumption of nutrients, growth, decomposition) is modeled by reaction terms which are, in general, nonlinear functions of all regarded concentrations. The reaction terms additionally include parameters (e.g. growth rates). Parameter identification, i.e., the determination of parameter values, enables the model's adjustment to the ecosystem in question. Parameter identification is a mathematical optimization problem. In applications, the model equation and the parameter identification problem are solved numerically. A satisfying assessment of numerical solutions requires information about the continuous model. In this work, we investigate the continuous equation of a general ecosystem model and the corresponding parameter identification problem. As a result, we obtain the existence of transient and periodic solutions. To prove the existence of transient solutions, we rely on standard methods (Galerkin's method, Banach's Fixed Point Theorem) which we adapt to the nonlinearly coupled systems of equations and the two types of reaction terms. In the periodic case, we investigate models which are solved by the constant zero function. The existence result ensures that, in addition, nontrivial periodic solutions exist. Concerning parameter identification, we prove the existence of optimal parameters for quadratically integrable data. In addition, we indicate first and second order optimality conditions and formulate the first order condition as an optimality system. We apply all theoretical results to the PO4-DOP model which is important for testing purposes. By means of a numerical test based on a two-dimensional version of the PO4-DOP model, we investigate uniqueness of numerically computed periodic solutions

Augmented Reality for Machine Maintenance Applications

Nowadays, organizations have to cope with different challenges, such as varying factors concerning the requirements of the markets, products, and services. Therefore, organizations have to constantly improve their business processes to keep up with these varying demands. For instance, the maintenance processes of a machinery and physical systems may have many different procedures depending on external process factors (such as customer requirements and specifications) and internal factors (i.e., utilized machines, machine types, attrition of machine parts, knowledge level of a maintenance operator). Ultimately, used process management concepts and systems have to support variability and context data management during modeling and execution time. This thesis develops a context- and process-aware information system to support maintenance operators with their daily work tasks. Thereby, augmented reality is used for interaction between a maintenance operator and the developed proof-of-concept implementation. The latter acquires sensor data from different information systems, executes and adapts executed process based on the current contextual situation, and visualizes augmented guidelines to maintenance operators in real time. By using such a context-aware process information system during a maintenance routine, organizations are able to improve quality and time efficiency of a maintenance routine

การผลิตน้ำมันไบโอดีเซลโดยใช้เครื่องปฏิกรณ์ต้นแบบพลังงานแสงอาทิตย์Biodiesel production by using the prototype solar reactor

บทคัดย่อ งานวิจัยนี้เป็นการนำเสนอการผลิตน้ำมันไบโอดีเซลชนิดกรดไขมันเมทิลเอสเทอร์ (FAME) โดยใช้เครื่องปฏิกรณ์ต้นแบบพลังงานแสงอาทิตย์ผ่านปฏิกิริยาทรานส์เอสเทอริฟิเคชัน น้ำมันปาล์มโอเลอินและน้ำมันพืชที่ใช้แล้วถูกใช้เป็นวัตถุดิบในการทำปฏิกิริยากับสารเมทานอล (CH3OH) และใช้สารโซเดียมไฮดรอกไซด์ (NaOH) เป็นสารตัวเร่งปฏิกิริยา จากการศึกษาพบว่าการใช้เครื่องปฏิกรณ์ต้นแบบพลังงานแสงอาทิตย์ในการผลิตน้ำมันไบโอดีเซลสามารถให้ความร้อนกับสารผสมอุณหภูมิเฉลี่ยอยู่ที่ 55±3๐C และพบว่าปฏิกิริยาเกิดสมบูรณ์ที่เวลาในการทำปฏิกิริยา 1 ชั่วโมง ได้ผลิตภัณฑ์น้ำมันไบโอดีเซลที่มีค่า %FAME สูงถึง 97.7% (±1%) โดยใช้เทคนิคนิวเคลียร์แมกเนติกเร-โซแนนซ์สเปกโตรสโคปี (NMR) และเทคนิคแก๊สโครมาโตกราฟ (GC) ในการวิเคราะห์น้ำมันไบโอดีเซลที่ได้ ปริมาณค่าร้อยละผลผลิตน้ำมันไบโอดีเซลที่ได้ (%yield) มีค่าเท่ากับร้อยละ 85±3 คุณสมบัติทางเคมีและทางกายภาพของน้ำมันไบโอดีเซลที่ได้มีคุณสมบัติผ่านตามเกณฑ์มาตรฐานหลัก ASTM D6751 และ EN14214 ที่เป็นเกณฑ์มาตรฐานสากล ดังนั้นการใช้เครื่องปฏิกรณ์ต้นแบบพลังงานแสงอาทิตย์สำหรับการผลิตน้ำมันไบโอดีเซลนี้ สามารถลดต้นทุนในส่วนการใช้พลังงานไฟฟ้าที่ต้องให้ความร้อนแก่สารผสมด้วยการใช้ความร้อนจากแหล่งพลังงาน        ดวงอาทิตย์ ถือเป็นนวัตกรรมและเทคโนโลยีที่ไม่ซับซ้อนเหมาะสำหรับการใช้งานในภาคครัวเรือนและวิสาหกิจชุมชนขนาดเล็กเพื่อการผลิตน้ำมันไบโอดีเซลไว้ใช้เองได้ในราคาต้นทุนที่ประหยัดAbstractThis work presents the biodiesel production as a fatty acid methyl ester (FAME) by using the prototype solar reactor via the transesterification reaction. Palm olein oil and waste cooking oil were used as a reactant which was attacked with methanol (CH3OH) in the presence of sodium hydroxide (NaOH) as catalysts. The results found that the prototype solar reactor could be heated the reaction mixture of 55±3๐C and the reaction completed at 1 h. %FAME of the obtained biodiesel product was achieved 97.7% (±1%) which was analyzed by nuclear magnetic resonance spectroscopy (NMR) and gas chromatography spectroscopy (GC) technique, and yield of biodiesel product was 85% (±3%). The main physicochemical properties of the obtained biodiesel meet all the ASTM D6751 and EN14214 standard specifications. Therefore, the use of prototype solar reactor for biodiesel production is the one way to reduce the requirement energy from electricity supply for heating the reaction mixture by the use substitute energy from solar energy source. This research is a simple innovation and technology which suitable for households and small community enterprises to produce the low-cost biodiesel fuel as a cheap energy sources