A Distillation-type Process for Thermal Decomposition of Complex Hydrocarbons by Film Boiling

CBET-1336657PI-Avedisian将凝聚相(液体)有机化学品转化为较轻的馏分，构成了一些化学加工工业的基础。目前的做法是将反应物液体分开蒸发，然后将气体输送到高温反应环境中。这项研究的首要目标是加深对支配一种独特的化学反应器概念运行的热/化学过程的理解，该概念将汽化与在基本上建立自身的反应空间中的分解紧密地结合在一起。这个概念涉及在浸没在反应物液体池中的加热表面上建立膜沸腾。当气泡不能以足够快的速度将能量从表面转移出去以避免合并时，就会出现这种热传递模式。然后在表面形成一层蒸汽膜，将其与周围的液体隔绝。在蒸汽膜上产生的温降可能超过1000度，即使液体相对较冷。这样的温度足以让有机气体分解。反应发生在蒸汽膜的物理空间，几乎完全由操作变量控制，最直接的是膜沸腾建立在其上的表面温度。如果表面温度降低到低于最低膜沸腾温度，那么反应堆就完全消失了。这种自组装在化学反应技术中是独一无二的。这项研究将研究薄膜沸腾的多功能性，以转化形成可凝结物种的有机反应物(可溶于反应物液体)，以及可加强液池安全壳密封的高沸点液体。将制造一种全玻璃蒸馏式的反应器设计，并将其应用于一系列具有分解复杂性的化学品，包括只会分解为具有已知反应速率常数的不可凝结气体的反应液、同时形成不可凝结气体和可凝结气体的化学品、具有许多转化步骤的液态碳氢化合物，以及在生物柴油生产过程中作为废物突出的化学品。该项目的主要成果将是更好地了解薄膜沸腾如何促进有机气体的化学反应，并采用适用于各种有机液体的实验设计。这项研究的成功将导致对汽化和传热过程的基本了解，这些过程支配着一种以薄膜沸腾为基础的新化学反应器技术，将有机化学品分解为更高价值的产品。例如，目前世界范围内甘油供过于求，因为它在生物柴油生产过程中形成，威胁到该行业的生存能力。薄膜沸腾固有的便携性和较高的气体温度表明，将纯甘油转化为合成气是可行的，有可能通过一个简单的过程从目前的废物产品中创造出一种有用的能源，从而使生物基种子油原料生产生物燃料的效率更高。

CBET-1336657PI-AvedisianThe conversion of condensed phase (liquid) organic chemicals to lighter fractions forms the basis of some chemical process industries. The current practice is to vaporize the reactant liquid separately and then transport the gases to the high temperature reaction environment. The overarching objective of this research is to develop the understanding of the thermo/chemical processes that governs operation of a unique chemical reactor concept which closely couples vaporization with decomposition in a reaction space that essentially builds itself. The concept involves establishing film boiling on a heated surface submerged in a pool of the reactant liquid. This heat transfer mode is developed when bubbles cannot transport energy away from a surface at a fast enough rate to avoid coalescence. A vapor film then forms on the surface which insulates it from the surrounding liquid. The resulting temperature drop across the vapor film can be more than a thousand degrees even though the liquid is comparatively cold. Such temperatures are more than sufficient for organic gases to decompose. The reaction occurs in the physical space of the vapor film that is controlled almost entirely by operational variables, most directly temperature of the surface on which film boiling is established. If surface temperature is lowered below the minimum film boiling temperature the reactor literally disappears. This aspect of self-assembly is unique among chemical reactor technologies. This research will investigate the versatility of film boiling to convert organic reactants that form condensable species which are soluble in the reactant liquid, and high boiling point liquids that can stress containment seals for the liquid pool. An all-glass distillation-type design for a reactor will be fabricated and applied to a range of chemicals with a progression of decomposition complexities, including a reactant liquid that will decompose only to noncondensable gases with a known reaction rate constant, a chemical that forms both noncondensable and condensable gases, a liquid hydrocarbon with many conversion steps, and a chemical that is prominent as a waste product in the biodiesel production process. The major outcome of the project will be a greater understanding of how film boiling promotes chemical reaction of organic gases with an experimental design that is applicable to a wide range of organic liquids. Success in this investigation will result in a fundamental understanding of the vaporization and heat transfer processes that govern a new chemical reactor technology based on film boiling for decomposing organic chemicals into more high-valued products. For example, there is currently a world-wide glut of glycerine due to its formation in the biodiesel production process that threatens the viability of the industry. The inherent portability and high gas temperatures of film boiling suggests its feasibility to convert pure glycerine to synthesis gas with potential to create a useful energy source from what is currently a waste product by a simple process that could make more efficient the production of biofuel from bio-based seed oil feedstocks.