Incineration and gasification technologies completed with up-to-date off-gas cleaning system for meeting environmental limits

It is shown how gasification can be used for processing wastes including “waste to energy” system. First, an analysis of incineration of wastes taking into account environmental limits is performed. This analysis is aimed at a typical arrangement of a conventional oxidizing incineration plant consisting of waste storage and feeding systems, two-stage incinerator (primary and secondary combustion chambers), heat recovery system involving co-generation and off-gas cleaning system. It is also focused on a new arrangement where the primary combustion chamber (rotary kiln) is substituted by gasification reactor. The proposed concept with a fluidised bed reactor utilizes results of experimental research with various mixtures of wastes (e.g. shredded textile and rubber) considering typical conditions of operation. Experiments provide us with various important characteristics (heat value of produced syngas vs. temperature in the gasification reactor, temperature in the secondary combustion chamber vs. oxygen concentration in outlet flue gas and heat value of syngas, etc.). Then it is possible to make a comparison of conventional incineration and gasification for a concrete industrial process involving a unit for thermal treatment of hazardous industrial waste mixed with municipal solid wastes with capacity of 10,000 t/year. The application of gasification technology brings about the whole range of benefits like minimizing the consumption of auxiliary fuel and decreasing size of the secondary combustion chamber and other subsystems of the incineration plants. Involving such a system with energy and investment cost reduction into an industrial process contributes to meeting cleaner production and environmental legislation regulations.     

Comparing domestic water heating technologies

Solar water heaters (SWH) and drain water heat recovery (DWHR) systems are two household technologies currently available in the marketplace that can lower usage of utility-supplied energy. While there is considerable interest in utilizing these technologies to reduce energy costs and environmental impact, actual implementation of these systems in houses remains low. This study examines possible reasons for this low adoption rate using Guelph (Ontario) as a case study representative of medium-sized Canadian cities. A model was created to determine the implementation rate required for each technology to meet the goals of Guelph's Community Energy Plan and the level of financial incentive required to achieve the desired implementation rate. Water conservation and the need to address both new development and the existing housing stock emerge as critical factors. Solar water heating was found to require significantly higher subsidies than drain pipe heat recovery, corresponding to a higher cost per unit of energy saved. Non-economic factors that reduce the adoption rate of new technology are discussed, and it is observed that a need for community education related to the new technologies and inertia associated with current water heating technology are the primary factors for adoption rates below levels predicted based on economics alone.     

Modelling and analysis of a business model to offer energy-saving technologies as a service

In this study, we present a stochastic model to analyse a business plan that is based on offering energy-saving technologies as a service. In this arrangement, the total differential cost of replacing an existing technology with a more efficient one is financed from the future energy savings that are shared between a service provider that installs the more efficient technology and its customer. The model we present captures improvements in energy efficiencies and costs of technologies with time, variation in energy consumption, uncertainty in energy prices and useful life of a technology, and revenue from carbon offsets. By using an analytical model, we analyse the feasibility of this business model using expected cost and also value-at-risk criteria. We show that when the service provider selects the contract parameters in a right way, the business plan brings financial benefits. The customer also benefits financially from reduction in energy usage and replacement costs, and also from additional revenue obtained through selling carbon offsets. Furthermore, since this business plan is based on increasing energy efficiency, the proposed approach decreases energy consumption, and therefore carbon dioxide emissions. As a result, using an analytical model, we show that offering energy-saving technologies as a service is a win–win–win situation for the service provider, its customer and for the environment.     

Photosynthesis of hydrogen and methane as key components for clean energy system

While researchers are trying to solve the world’s energy woes, hydrogen is becoming the key component in sustainable energy systems. Hydrogen could be produced through photocatalytic water-splitting technology. It has also been found that hydrogen and methane could be produced through photocatalytic reduction of carbon dioxide with water. In this exploratory study, instead of coating catalysts on a substrate, pellet form of catalyst, which has better adsorption capacity, was used in the photo-reduction of carbon dioxide with water. In the experiment, some water was first absorbed into titanium dioxide pellets. Highly purified carbon dioxide gas was then discharged into a reactor containing these wet pellets, which were then illuminated continuously using UVC lamps. Gaseous samples accumulated in the reactor were extracted at different intervals to analyze the product yields. The results confirmed that methane and hydrogen were photosynthesized using pellet form of TiO₂ catalysts. Hydrogen was formed at a rate as high as 0.16 micromoles per hourμmol h^–1). The maximum formation rate of CH₄ was achieved at 0.25 μmol h^–1 after 24 h of irradiation. CO was also detected.     

Stationary analysis of a solar LiBr-H2O absorption refrigeration system

The present work describes the operation of a solar powered absorption cooling system. This solar cooling installation was designed in order to resolve the overheating problems of an existing solar field. Since 2007 the system was completely monitored to be able to analyze it. The work evaluates the performance of this kind of installation as well as the behavior of the absorption chiller focusing on its steady state operation.This methodology was applied to the monitoring results of the installation in order to compare the first two years of operation of the system. It is concluded that the performance of the chiller showed better values in 2007 because the heat rejection temperature and the outdoor temperature were more favorable than in 2008. Nevertheless, the coefficient of performance (COP) achieved acceptable values in both periods, over 0.5, being the average chilling capacity between 3.6 kW and 5.8 kW.     

把我国广大的沙化草原建设成为可再生的世界级特大的清洁能源生产基地

中国有广大的约占国土面积40%的沙化退化草原,不宜亦没有用作粮食耕地。但经过大力的生态建设后每年能产出巨量的巨银草。后者是原生在中国北部,能耐干寒和恶劣环境,并是多年生高达3.5 m的巨大稠密的野草,并能利用咸水。将这些巨银草气化催化后估计每公顷可产出17.2 t的可直接替代汽油的生物丁醇,生化和基因研发专业公司孟山都和孟代尔等己开始合力提升此产能,估计到2030年左右,以沙化草原的约46%的面积种植巨量的巨银草,可使中国开始不再依赖石油和煤炭的化石能源,而转用由巨大的"巨银草油田群"供应的可再生的清洁能源,其余的面积的产量可供外销或作他用,使中国能长期成为世界能源强国,与他国合力稳定能源供应和价格,并引领世界迈向可再生的清洁能源新时代。     

Using cooling load forecast as the optimal operation scheme for a large multi-chiller system

Energy saving is one of the most important issues in high-tech manufacturing industries, such as semiconductor and electronics, because large chilled water systems are used to satisfy big cooling load requirements. In this paper, a new optimal integrity scheme based on a two-stage strategy, including a scheduling stage and an operating stage, is proposed to minimize the system energy consumption within a future time period. Instead of a lag scheme used in the general method, a forecasting scheme consisting of a series of optimal schemes at each sub-time period is also proposed for the two-stage design. The performance of the proposed method is examined through an industrial case. The cost of the proposed method is much less than that of the conventional method, so the proposed method is cost-efficient in applications of large air-conditioning systems.     

川气东送工程节能环保技术的创新与应用

针对川东北地区敏感脆弱的生态环境及含剧毒高酸天然气的资源禀赋,始终坚持并严格落实"环保优先"的工程建设指导思想,大力推行以"节能环保、绿色低碳"为主要特征的生态工程建设模式,将系统优化思想与节能环保技术创新相结合、清洁生产措施与严格监管相结合,在优化设计、清洁生产、环境监测全过程推进节能环保技术的创新与应用,杜绝了重特大环境污染和生态破坏事故的发生,最大限度减少了工程建设对原始生态环境和人文历史环境的影响,实现了污染物排放浓度、总量和环境质量达标,履行了将川气东送工程建设成"生态工程"、把普光气田建设成"绿色气田"、把川气东送管道建设成"绿色能源大走廊"的社会承诺。     

Effect of stochasticity on targeted energy transfer from a linear medium to a strongly nonlinear attachment

In this work the problem of targeted energy transfer (TET) from a linear medium to a nonlinear attachment is studied in the presence of stochasticity. Using a Green’s function formulation, complexification-averaging technique and diffusion approximation we derive a complex, nonlinear, Ito stochastic differential equation that governs the slow dynamics of the system. Through the numerical solution of the corresponding Fokker-Planck-Kolmogorov (FPK) equation we study the optimal regime of TET and its robustness to stochasticity for the case of nonlinear interactions of the nonlinear attachment with a single mode of the linear system. The probabilistic analysis reveals that in the presence of stochasticity the optimal TET regime, predicted in the deterministic theory, is not only preserved but also is enhanced due to the interaction of nonlinearity and stochasticity.     

氮气液化装置的扩容改造

针对化工生产连续性和空分装置启动周期长的特点 ,仪征化纤股份有限公司动力厂建有一套氮气液化及贮存、输送装置 ,作为空分装置故障的后备供氮手段。近 2 0年来 ,随着仪化公司的不断扩展和市场经济的逐步建立 ,动力厂紧紧围绕满足公司内部和扩大市场销售两个目标 ,对该套装置进行了多次扩容改造。使运行可靠性增强 ,产量增加 ,成本降低 ,市场竞争力加强 ,取得了明显的经济效益。1　原装置简介表 1　氮气液化装置主要设计性能参数项目设计值氮气液化量 70 0～ 10 0 0ｍ3 /ｈ原料氮气压力 1 6ＭＰａ循环制冷氮气量 70 0 0ｍ3 /ｈ循环氮气压力…     

A propane water-to-water heat pump booster for sanitary hot water production: Seasonal performance analysis of a new solution optimizing COP

Electrical heat pumps for sanitary hot water production achieve a high performance with a good matching of water and refrigerant temperature profiles during the heat rejection stage, as it happens in CO₂ systems. This work considers the thermodynamic possibility to adapt the condenser pressure of a propane heat pump to maximize the COP, while producing sanitary hot water up to 60 °C from a heat sink equal to 15 or 25 °C. The performance of the heat pump is calculated through specific models which, in combination with a TRNSYS model of the whole system, allowed to assess its seasonal performance for a hotel in Strasbourg, also varying the control logic and the size of the storage tank. Results obtained led to the conclusion that, for achieving a high seasonal performance, the control logic of the tank has the largest influence.     

A two-stage robust programming approach to demand-driven disassembly planning for a closed-loop supply chain system

The closed-loop supply chain system, which integrates forward and reverse logistics, is a desirable policy for retaining recoverable resources and extending the life cycles of products. In this study, we propose a methodology to contend with a demand-driven disassembly planning problem under a closed-loop supply chain system. A two-stage robust programming model is developed correspondingly, such that multiple products with a hierarchical product's structure are disassembled to satisfy uncertain demands in multiple periods. The objective of the model is to determine a robust decision for recycle volume and timing of each type of end-of-life (EOL) product, as well as recovery strategies. The results provide two-stage decisions by considering future scenarios of periodic demands at the beginning of a planning horizon. The first-stage decision is to determine a compromise solution that is close to the optimal solution for every scenario while retaining a certain level of infeasibility of constraints, such as unsatisfied demand. Afterward, when the outcome of a scenario has been realised, the second-stage decision, such as, inventory volume, is conducted to become a buffer for mitigating uncertain impacts. Furthermore, the computational results confirm the trade-off relationship between solution robustness and model robustness, which are core results of the robust model apart from expected profit. The different types of decision makers’ preferences toward risk can be accounted for to determine a compromise robust solution.     

Cumulative nonlinearity as a parameter to quantify mechanical fatigue

The cumulative nonlinearity (Q_f) is proposed as a new parameter to quantify mechanical fatigue. The parameter Q_f represents the (cycle number) integral of the ratio of the third harmonic to the fundamental one (I_3/1), obtained via Fourier transform of the stress (torque), normalized by the square of the strain amplitude (γ₀). The validation is performed on different polymers: polystyrene (PS) with different molecular weights, styrene‐acrylonitrile (SAN), polymethylmethacrylate (PMMA), and polytertbuthylmethacrylate (PtBMA) under strain controlled fatigue tests in a torsion rectangular set‐up. A power‐law correlation between the number of cycles to failure (N_f) and the cumulative nonlinearity was found for N_f > 1000 cycles, and the results were compared with well‐established failure criteria such as the cumulative stress and the dissipated energy density. It was found that the cumulative nonlinearity has superior prediction ability since it can quantify material changes during a test.     

Perovskites with Enriched Oxygen Vacancies as a Family of Electrocatalysts for Efficient Nitrate Reduction to Ammonia

Electrochemical nitrate reduction to ammonia (NRA) provides an efficient, sustainable approach to convert the nitrate pollutants into value-added products, which is regarded as a promising alternative to the industrial Haber–Bosch process. Recent studies have shown that oxygen vacancies of oxide catalysts can adjust the adsorption energies of intermediates and affect their catalytic performance. Compared with other metal oxides, perovskite oxides can allow their metal cations to exist in abnormal or mixed valence states, thereby resulting in enriched oxygen vacancies in their crystal structures. Here, the catalytic activities of perovskite oxides toward NRA catalysis with respect to the amount of oxygen vacancies are explored, where four perovskite oxides with different crystal structures (including cubic LaCrO₃, orthorhombic LaMnO₃ and LaFeO₃, hexagonal LaCoO₃) are chosen and investigated. By combining X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy and electrochemical measurements, it is found that the amount of oxygen vacancies in these perovskite oxides surprisingly follow the same order as their activities toward NRA catalysis (LaCrO₃ < LaMnO₃ < LaFeO₃ < LaCoO₃). Further theoretical studies reveal that the existence of oxygen vacancies in LaCoO₃ perovskite can decrease the energy barriers for reduction of *HNO₃ to *NO₂, leading to its superior NRA performance.