铀在不同煤阶煤生烃演化过程中的影响

Coal-formed gas plays a significant role in the world energy structure. And inorganic component co-existed with coal has crucial effects on the whole process of the hydrocarbon generation of coal. Uranium shows an excellent catalysis property due to its special atomic structure. Former studies indicate that uranium has significant effects on the whole process of the hydrocarbon generation of the source rock or brown coal. And further study is worthwhile and needed to find out whether uranium affects the hydrocarbon-generation process of other different rank coals and how uranium affects the process if the influence exists as well as the mechanism. The hydrocarbon- generating simulation experiment will be conducted using different rank coals with uranium added to study the effects of uranium on the hydrocarbon generation of different rank coals as well as the mechanisms by contrasting the yields and characteristics of experimental products, especially the characteristics of gaseous hydrocarbon, liquid hydrocarbon, natural gas components, gas chromatography of saturated hydrocarbon, GC-MS and δ13C of natural gas molecule of experimental products at different experimental temperatures and apply infrared spectroscopy and δ13C nuclear magnetic resonance spectrum and so on to study structural changes of coal macerals and he maturity of organic matter. The implement of the project will enrich the study of hydrocarbon-generation mechanisms, deepen the genetic theory of oil and gas formation and provide some references for a new estimation of resource reserve from hydrocarbon generation of coal and the exploration and development of resource, which may provide the basis for accumulation system of coexisting multi-energy minerals including oil, gas, coal and uranium and their cooperative exploration and comprehensive development.

煤成气在世界能源结构中占有非常重要的地位。煤中伴生的无机组分在煤生烃演化过程中具有重要的影响。铀因其特殊的原子结构，具有良好的催化性能，已有研究表明铀对烃源岩/褐煤生烃演化的全过程都具有重要影响。铀对其它煤阶煤的生烃演化有无影响？如果有，如何影响?作用机理又是什么?这些都值得开展进一步的研究。该项目拟通过在不同煤阶的煤中加入铀的条件下进行生烃模拟实验，对比不同模拟实验温度下产物的量及特征，尤其是气态烃、液态烃、天然气组分、产物色谱、色质特征、天然气分子碳同位素δ13C特征，并对实验产物应用红外光谱、13C核磁共振波谱等分析，研究煤显微组分结构变化，确定有机质成熟度，来探讨铀对不同煤阶煤生烃演化的影响及作用机理。该项目的顺利实施将会丰富煤成烃机理的研究，深化和完善油气成因理论，为煤成烃资源量的重新估算及勘探开发提供一定的参考，为多能源矿产共存成藏（矿）机理的研究及协同勘探与综合开发提供依据。

油、气、煤、铀多种能源不仅可以同盆共存，而且形成演化富集成矿的过程中普遍存在有机-无机相互作用。本项目研究了铀可能对有机煤的生烃演化过程及产物产生的影响。本项目利用黄金管热模拟装置，根据有无碳酸铀酰溶液的加入，选择长焰煤、气煤、肥煤等不同煤阶的煤在温度点300°C, 325 °C, 350 ℃, 375℃, 425 °C和450℃进行生烃模拟实验，并对实验中产生的气态烃和液态烃进行了定量收集以及气相色谱和色谱质谱分析，实验结果表明：铀的加入对于长焰煤和气煤生烃具有提高生烃量的作用；铀的加入提高了长焰煤液态烃的产率，促进长链烃向短链烃、不饱和烃向饱和烃的转化；铀的存在降低了肥煤气态烃产率。在低温阶段，铀的存在增加了有机质的成熟度；在高温阶段，铀的存在降低了有机质的成熟度，抑制了烷烃异构化程度。铀的浓度变化对煤生烃演化具有一定的影响，从铀对长焰煤生烃模拟实验来看，铀浓度过高，其对煤生烃促进作用越弱。从长焰煤、气煤、肥煤三者生烃实验产物总气体和气态烃产率来看，煤的变质程度越高，其生气能力可能越强。相关认识丰富了煤成烃机理的研究，深化和完善油气成因理论，为煤成烃资源量的重新估算及勘探开发提供一定的参考，为多能源矿产共存成藏（矿）机理的研究及协同勘探与综合开发提供依据。