Micro-CHP using steam ejector/water turbine (WaterGen)

使用蒸汽喷射器/水轮机 (WaterGen) 的微型热电联产

• 批准号: EP/N509875/1
• 负责人: Saffa Riffat
• 金额: $ 18.96万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FN509875%2F1
• 关键词: Micro; CHP; using; steam; ejector

This project will develop an innovative, generic micro-CHP using steam ejector/water turbine (WaterGen), based on an application of existing steam-ejector/water-turbine/wheel technology, which, can bring additional power generation andcarbon reduction solutions over the next decade by the more efficient utilisation of both natural gas and renewable energy. For safety, stability and cost, water is the ideal working fluid. The new technology will address the fundamental UK energysupply problems.The project will include a computer program model the theoretical performance of WaterGen. According to the simulations conducted, for entrainment ratios (W steam / W water) 1/2 to 1/9, efficiency (Wnet / Qboiler) is found in the range of 21% to34%. For the same operating conditions ORC efficiency is found as ~7%. Additional simulations carried out to determine the cycle efficiency for the increasing steam (motive fluid) pressure entering the injector. Entrainment ratio is kept constantas 1/5 in this analysis. It is found that increasing steam pressure in the range of 1 -5 bar slightly decreases the cycle efficiency from 31% to 30% whilst for the same conditions ORC efficiency varies between 6.5-7.5%. In overall it is found that injector/water cycle has a promising potential to turn low temperature heat (100-150C waste heat /solar energy) into useful power. For the same operating conditions injector/water cycles can provide 4-5 times higher efficiency in comparison with currently used ORC cycles. Moreover, a "proof of concept" rig will be constructed and operated at UoN based on a steam ejector, designed and supplied by Venturi Jet Pumps Ltd (VJP), mated with a commercially available PowerSpout micro-hydroelectric Pelton wheel/generator specified and supplied by Ashwell Biomass Ltd (ABM). The rig will have a nominal electrical output in the range 1 to 1.5 kW. Turbine water flows will be ~ 5 to 25 L/s with heads of 20 to 100 m. The thermal output will be ~ 10 to 15 kW at temperatures in the range 30 to 70C. This scale is small enough for lab operation,but large enough to obtain meaningful results and to prove the concept. The latter will be fed into the model to assess the performance of larger installations. The consortium is confident that WaterGen can be scaled up, both by adding more units, commonly done in HE schemes, or by using larger turbine/generator/wheel sets for industrial applications.The steam/water ejector with low cost and easy to manufacture wheel is expected to have good efficiency in converting steam energy into power. The assertion, sometimes made, that steam ejector pumps have low efficiency appears to be incomparison with electric pumps; but this ignores the losses in generating the electric power to drive the pump so is not a valid comparison. Reasons for anticipating that the overall WaterGen efficiency will be high enough including the following: 1) the lower vapour pressure of water and its good thermal stability means it can operate at higher input temperatures than organic fluids resulting in higher Carnot efficiency. 2) A recent paper indicates experimental steam/water ejector efficiencies can reach 0.85 of the theoretical maximum. 3) Work by Burns suggests that air injection into steam ejector pump improves efficiency. 4) Although the higher the efficiency the better what really matters in a practical unit is the cost/kWh of the power delivered based on its capital and operating costs...WaterGen is anticipated to be a low cost design and higher efficiency than ORC steam expander. The minimum target for the power output is 10% based on the energy input to the boiler. In a developed system efficiencies of 15-20% could be achievable.

该项目将基于现有蒸汽喷射器/水轮机/水轮技术的应用，开发一种创新的、通用的微型热电联产（WaterGen），通过更有效地利用天然气和可再生能源，可以在未来十年带来额外的发电和碳减排解决方案。在安全性、稳定性和成本方面，水是理想的工作流体。这项新技术将解决英国能源供应的根本问题。该项目将包括一个计算机程序模型来模拟WaterGen的理论性能。模拟结果表明，当蒸汽/水的夹带比为1/2 ~ 1/9时，锅炉的效率为21% ~ 34%。在相同的运行条件下，ORC效率为~7%。为了确定进入喷射器的蒸汽（动力流体）压力增加时的循环效率，还进行了额外的模拟。在此分析中，夹带比保持恒定在1/5。研究发现，当蒸汽压力在1 - 5bar范围内升高时，循环效率从31%略微降低到30%，而在相同条件下，ORC效率在6.5-7.5%之间变化。总的来说，喷射器/水循环在将低温热（100-150℃废热/太阳能）转化为有用的动力方面具有很好的潜力。在相同的操作条件下，与目前使用的ORC循环相比，注入器/水循环可以提供4-5倍的效率。此外，一个“概念验证”钻机将在UoN建造和运行，该钻机基于由Venturi喷射泵有限公司（VJP）设计和提供的蒸汽喷射器，与Ashwell生物质有限公司（ABM）指定和提供的商用PowerSpout微型水力发电轮/发电机相匹配。该钻机的标称电力输出范围为1至1.5 kW。水轮机水流量为5 ~ 25升/秒，水头为20 ~ 100米。在温度范围为30至70℃时，热输出将为~ 10至15 kW。这个规模对于实验室操作来说是足够小的，但对于获得有意义的结果和证明这个概念来说是足够大的。后者将被输入到模型中，以评估大型装置的性能。该联盟相信，WaterGen可以通过增加更多的单元（通常在HE方案中完成）或通过在工业应用中使用更大的涡轮机/发电机/轮组来扩大规模。蒸汽/水喷射器具有成本低、易于制造的特点，有望在蒸汽能量转化为动力方面具有良好的效率。有时有人断言，蒸汽喷射泵效率低，似乎与电动泵相比；但这忽略了产生驱动泵的电力的损失，因此不是一个有效的比较。预计整体水能效率足够高的原因包括：1)水的蒸气压较低，热稳定性好，可以在比有机流体更高的输入温度下运行，从而获得更高的卡诺效率。2)最近的一篇论文表明，实验汽/水喷射器效率可以达到理论最大值的0.85。3) Burns的工作表明，向蒸汽喷射器泵注入空气可以提高效率。4)虽然效率越高越好，但在实际装置中真正重要的是基于其资本和运营成本的每千瓦时电力交付成本……WaterGen预计是一种低成本设计，比ORC蒸汽膨胀器效率更高。根据锅炉输入的能量，输出功率的最小目标是10%。在一个发达的系统中，效率可以达到15-20%。