Dynamic Organic Rankine Cycle for Recovering Industrial Waste Heat

英国设定的目标是到2050年将温室气体排放量在1990年的基础上至少减少80%。为了实现这一目标，将需要减少约40%的能源消耗，因此必须大幅提高能源效率。从工业废热资源中回收能源被认为对提高能源密集型工业部门的整体能源效率作出了重大贡献。在英国，能源与气候变化部(DECC)最近发布的一份报告确定了每年48太瓦时的工业废热来源，相当于英国工业能源消耗的六分之一左右。尽管余热回收受到工业界的广泛欢迎，但由于许多障碍，英国工业部门缺乏余热回收系统，最重要的是效率低下。预计到2018年，全球余热回收系统市场价值将增长至530亿美元，2013至2018年的复合年增长率为6.5%。不用说，创新的余热回收技术在国内和全球都有巨大的市场。虽然有几种(处于不同发展阶段)的余热回收替代技术，如热交换器、热泵、斯特林发动机和卡利纳循环发电厂，但有机朗肯循环系统在实践中仍然是最有前途的。大型有机朗肯循环系统在高温应用上是可行的，然而，它们在低温余热(&lt；250摄氏度)中的应用还处于初级阶段。然而，英国超过60%的工业废热来源处于低温区间(摄氏250度)。有机朗肯循环技术供需明显不匹配，因此创新研发需求旺盛。这是第一个赠款计划项目，针对DECC确定的工业废热回收挑战，旨在开发一种创新的动态有机朗肯循环(ORC)系统，该系统使用二元共沸混合物作为工作介质，并具有在运行期间动态调整混合物组成的机制，以适应不断变化的散热器温度，因此所产生的系统可以实现显著更高的年平均效率。初步研究表明，动态有机朗肯循环系统每年利用低温余热产生的电力可能比传统系统多10%以上。该研究将首次提出一种新的动态有机朗肯循环概念，将组成调整机构集成到有机朗肯循环系统中，以便在电厂运行期间对混合物的组成进行调整。为了模拟和演示这种动态有机朗肯循环系统的工作原理和效益，将建立一个稳态的数值模型。建立动态数值模型，对混合料组成调整的控制策略进行仿真和优化。最后，设计并构建了该动态有机循环系统的原型。动态有机朗肯循环的概念和两个数值模型将通过全面的实验研究来验证。通过该项目开发的动态有机朗肯循环电厂可广泛应用于钢铁、陶瓷、水泥、食品等高耗能行业，可实现更高的效率，投资回收期可大幅缩短，从而使从工业废热资源中回收能源更有利可图。这些废物回收发电厂的广泛安装，最终将减少这些工业部门的能源需求，从而改善我们的能源安全。

The UK has set a target to cut its greenhouse gas emissions by at least 80% by 2050, relative to 1990 levels. To achieve this target, a reduction in energy consumption of around 40% will be required, and therefore significant improvements in energy efficiency are necessary. Energy recovery from industrial waste heat sources is considered to offer a significant contribution to improving overall energy efficiency in the energy-intensive industrial sectors. In the UK, a report recently published by the Department of Energy & Climate Change (DECC) identified 48 TWh/yr of industrial waste heat sources, equivalent to around one sixth of UK industrial energy consumption. Although waste heat recovery is broadly welcomed by industry, there is a lack of implementation of waste heat recovery systems in UK industrial sectors due to a number of barriers, the most important being poor efficiency. The forecast for global waste heat recovery systems market value is growth to 53 billion US Dollar by 2018, with a compound annual growth rate of 6.5% from 2013 to 2018. Needless to say, there is a huge national and global market for innovative waste heat recovery technologies. Although there are several alternative technologies (at different stages of development) for waste heat recovery, such as heat exchanger, heat pump, Stirling engine and Kalina Cycle power plant, the Organic Rankine Cycle system remains the most promising in practice. Large Organic Rankine Cycle systems are commercially viable for high-temperature applications, however, their application to low-temperature waste heat (<250 Degree C) is in its infancy. Yet more than 60% of UK industrial waste heat sources are in the low temperature band (<250 Degree C). There is clearly a mismatch between Organic Rankine Cycle technology supply and demand, so innovative research and development are highly in demand. This First Grant Scheme project, in response to the challenge of industrial waste heat recovery identified by DECC, aims to develop an innovative Dynamic Organic Rankine Cycle (ORC) system that uses a binary zeotropic mixture as the working fluid and has mechanisms in place to adjust the mixture composition dynamically during operation to match the changing heat sink temperatures, and therefore the resultant system can achieve significant higher annual average efficiencies. The preliminary research shows that a Dynamic Organic Rankine Cycle system can potentially generate over 10% more electricity from low temperature waste heat sources than a traditional one annually. The research will firstly develop a novel Dynamic Organic Rankine Cycle concept by integrating a composition adjusting mechanism into an Organic Rankine Cycle system, so that the mixture composition can be adjusted during the operation of the power plant. A steady-state numerical model will be developed to simulate and demonstrate the working principle and benefits of such a Dynamic Organic Rankine Cycle system. A dynamic numerical model will then be developed to simulate and optimise the control strategy of mixture composition adjustment. Finally, a prototype of such Dynamic Organic Cycle system will be designed and constructed. The Dynamic Organic Rankine Cycle concept and the two numerical models will be validated through a comprehensive experimental research. The Dynamic Organic Rankine Cycle power plants developed through this project can be widely applied to energy intensive industrial sectors such as the iron and steel industry, ceramic manufacturers, cement factories, food industrial, etc. As such power plants can achieve a much higher efficiency; the payback period can be significantly reduced, which would make energy recovery from industrial waste heat sources more profitable. The wide installation of such waste recovery power plants will ultimately reduce the energy demand of these industrial sectors, and therefore improve our energy security.