复杂环境下不饱和烯烃制冷剂的燃爆特性与抑制机理的研究

The unsaturated fluorinated olefins (HFOs) have been considered as one of the low climate effect candidates of the next generation refrigerants. Most of the currently attention is focused on its thermophysical properties and toxicities, and few of which touched the fundamental flammable characteristics of only R1234yf and R1234ze(E) under the quasi-static conditions. However, it has not been explored out for the multi-combustible characteristics and inerting mechanism of the HFOs refrigerants under the variable and actual conditions. The previous research achievements show that the physicochemical properties and molecular structures of HFOs are special with multiple isomerides, and which possess the potential of replacing the current refrigerants by mixing with other fluids. Therefore it is urgent and necessary to research the flammable characteristics and inerting mechanism of HFOs under complex environmental conditions with scientific methodology. In this project, researchers are planning to firstly analyze the microcosmic characters of HFOs molecules, then testing the multi-combustible characteristics of HFOs and inerting efficiencies of various typical fire retardants basing on the self-made test rig built on the national/international standards. By means of studying the combustion and inerting mechanism of the flame retardants under alterable conditions, the inerting factors and anti-oxidation mechanism can be recognized. In addition, research the essential relationship of HFOs refrigerants, fire retardants and the surrounding conditions quantificationally. Finally, the objective laws and scientific principles of HFOs combustion and inhibition can be achieved. The whole work is benefit to the new standards of working fluids concerning environmental protection and process safety.

HFOs作为新一代低环害制冷剂之一，其热物性及安全性倍受制冷界关注。目前HFOs的关注焦点集中于基础热物性和毒性研究，其中为数不多的可燃性研究大多局限于准静态环境下R1234yf和R1234ze(E)的基础燃爆特性参数测试方面，对于HFOs类制冷剂在多变环境下的可燃特性和惰化机理尚不明确。前期研究表明：HFOs同分异构体多、性质特殊，且可形成替代潜力较大的混合制冷剂，如何科学认识HFOs在复杂环境条件下的燃爆特性和惰化机理是亟待探索的科学问题。本课题拟从不饱和烯烃制冷剂的元素组成和分子结构等微观层面出发，结合高精度变环境燃爆特性测试，剖析HFOs类制冷剂在变环境下的燃爆机理，探索各类阻燃物质的变环境惰化因子和抗氧化还原机制，量化HFOs制冷剂可燃和阻燃特性及与环境特性间内在本质关系，探明HFOs制冷剂燃爆引发和惰化的客观规律和科学准则，为建立新一代低环害工质安全标准提供科学依据和数据参考。

不饱和烯烃HFOs类制冷剂作为新一代环保制冷剂之一，其热物性及安全性倍受制冷界关注。目前HFOs的关注焦点主要集中于基础热物性、传热特性以及系统性能等方面，但是其应用于实际制冷系统中仍然会有许多关键技术问题亟待解决，其中可燃性是其安全运用于实际系统的关键问题之一。目前国内外对于HFOs制冷剂的可燃性研究大多局限于准静态环境下R1234yf和R1234ze(E)的基础燃爆特性参数测试方面，对于HFOs类制冷剂在多变环境下的可燃特性和惰化机理尚不明确。为此本项目在以下五点开展深入研究：1、从不饱和烯烃制冷剂的元素组成和分子结构等微观层面出发，剖析了HFOs类制冷剂的燃爆机理。2、建立了环境参数可控的工质基础燃爆特性参数与动态影像记实综合试验系统，完成多种环境条件下的HFOs制冷剂燃爆极限参数和火焰传播特性的测试，获得典型HFOs制冷剂在较宽工况区间内的燃爆特性资料和现场影像记实。3、研究表明温度对典型HFOs制冷剂的燃烧极限呈线性关系；湿度对R1234yf燃烧极限作用较弱，但对R1234ze(E)的影响极大；而当特定气流扰动存在时，R1234yf的可燃下限会升高至7.7%；探明了HFOs 制冷剂燃爆特性的主要影响因素及作用规律；4、结合多类阻燃剂对典型HFOs制冷剂的阻燃机理分析与抑制惰化试验，得到了R227ea、R134a对R1234yf和R161、R152a对R1234ze(E)的燃爆特性参数的影响，揭示了阻燃剂对HFOs制冷剂的抑制效率和惰化机理。本项目弥补了当前HFOs制冷剂燃爆特性数据和动态影像数据的缺失，为新一代环保可燃制冷剂安全替代奠定理论依据与基础数据。