SBIR Phase II: Simple and Effective Fouling Release Coatings To Make Industrial Heat Exchangers More Energy Efficient

这一小型企业创新研究(SBIR)第二阶段项目将进一步开发一种创新涂层并将其商业化，以最大限度地减少工业热交换器表面矿物质污垢的积累。热交换器用于加热或冷却工业过程中的流体，如化学制造、炼油、发电、食品加工、电子制造等。工厂和大型商业建筑的空调也代表了热交换器的大量使用。当水中自然溶解的矿物质，通常被称为“硬”水，当它接触到热的表面时，从水中沉淀出来，就会产生污垢。这种污垢可以在典型的家庭茶壶或淋浴喷头的表面上看到。由此产生的矿物晶体具有很强的粘附性，并形成绝缘层，大大降低了工业热交换器的热效率。据估计，矿物污染每年给美国工业造成400亿美元的损失，浪费30亿美元的能源，相当于美国温室气体排放的1%以上。除了浪费能源，这一世界性的、永无止境的问题还增加了工厂停机和维护成本，导致工业在水供应的化学处理上花费了大量资金，并降低了热交换系统的使用寿命。一种有效的涂层将带来巨大的环境效益，包括消除因浪费的能源而产生的温室气体排放，以及减少最终进入社区污水流的水处理化学品。涂层材料是一种低表面能、自组装的疏水材料，由主体聚合物和纳米颗粒组成。涂层的低表面能阻碍了矿物与涂层换热表面的附着。第一阶段的结果表明，涂层表面上积聚的任何污垢都表现出较低的附着强度，这使得确实发生的任何污垢主要被流过它的水的力量清除-这种现象被称为“自清洁”。涂层非常薄--小于500 nm--由于涂层本身的存在，这使得热阻抗降至最低。第二阶段的研究将集中于优化涂层的性能，包括基材附着力、表面能和韧性，以确保在工业条件下的使用寿命。这将通过改变主体聚合物的化学以促进自组装来实现，也通过改变纳米颗粒的化学以获得主体聚合物和纳米颗粒之间的共价键来实现。还将进行工业规模应用程序的设计工作，并在工业现场通过现场试验验证实验室结果。

This Small Business Innovation Research (SBIR) Phase II project will further develop and commercialize an innovative coating which minimizes the accumulation of mineral fouling on industrial heat exchanger surfaces. Heat exchangers are used to heat or cool fluids in industrial processes, such as chemical manufacturing, oil refining, power generation, food processing, electronics manufacturing, and many more. Air conditioning for factories and large commercial buildings also represents a significant use of heat exchangers. Fouling occurs when naturally dissolved minerals in water, often called "hard" water, precipitate out of the water when it contacts a hot surface. This fouling can be seen in a typical home on the surface of a teakettle or showerhead. The resulting mineral crystals adhere strongly, and form an insulating layer that materially reduces the thermal efficiency of industrial heat exchangers. Mineral fouling is estimated to cost U.S. industry $40 Billion per year, and waste $3 Billion of energy, representing upwards of 1% of U.S. greenhouse gas emissions. In addition to wasting energy, this worldwide, never-ending problem increases factory downtime and maintenance costs, causes industry to spend large amounts on chemical treatment of water supplies, and decreases the useful life of heat exchanger systems. An effective coating will result in substantial environmental benefits including the elimination of greenhouse gas emissions resulting from the wasted energy, and a reduction of the water treatment chemicals, which eventually enter community wastewater streams.The coating material is a low surface energy, self-assembling hydrophobic material which is a composite of a host polymer and a nanoparticle. The low surface energy of the coating impedes the attachment of the minerals to the coated heat transfer surface. Phase I results showed that any fouling accumulation on a coated surface exhibits low adhesion strength, which allows any fouling that does occur to predominantly be dislodged by the force of the water flowing over it - a phenomenon call "self-cleaning." The coating is very thin - less than 500 nm - which minimizes impedance of heat transfer due to the presence of the coating itself. Phase II research will focus on optimizing the properties of the coating, including substrate adhesion, surface energy, and toughness to ensure a useful life under industrial conditions. This will be accomplished by changing the host polymer chemistry to facilitate self-assembly, and also by changing the chemistry of the nanoparticle to obtain a covalent bond between the host polymer and nanoparticle. Work will also be performed to design the application process for industrial scale, and validate lab results with field trials at industrial sites.