地面分解法开采海底天然气水合物

在海底和永久冻土地带天然气水合物的储量巨大，很多国家加大了对海底天然气水合物的勘探和研究力度。由于受物理化学特性的影响，天然气水合物在压力、温度改变的情况下会发生分解，海底天然气水合物的开采难度大。热溶法、抑制剂刺激法等理论方法都不适合于海底表层天然气水合物的开采。介绍了地面分解法这一天然气水合物开采的新方法，该方法利用海底采矿技术，将水合物通过管道输送到海上平台，加以分解利用。该方法在理论上克服了海底天然气水合物在海底分解时吸收热量使周围环境温度降低而无法继续进行的困难，也克服了不能用传统的减压法开采等缺点，具有简单、经济适用，能长期工作等特点。但在实际生产中，需要对工作参数的合理确定、沉渣排放对海洋环境的影响等问题进行深入研究。

EXPLOITATION OF NATURAL GAS HYDRATE BY GROUND DECOMPOSITION METHOD

Since natural gas hydrates (NGH) are vast energy resource with global distribution in the permafrost and in the oceans, more and more countries have maken efforts in exploration and development of NGH. However, great difficulty still exists in exploiting NGV from the bottom of the sea because the molecular structure of NGH will break down due to the change of pressure and temperature. The previous methods either heating by thermit or stimulating by inhibitors will not fit for the exploitation of NGH from the sea floor. This paper introduces a new exploitation method of ground decomposition to tap NGH. In this method, sea mining technology is adopted to extract NGH from sea floor through pipelines to the offshore platform, where NGH can be decomposed and utilized. In theory, this method can overcome many shortcomings by the other methods and vital difficulties which all operations have to stop by the decreasing temperature resulted from direct decomposition of NGH. This method has been proved to be practical and simple and be able to work for a long time in application. However, in actual working experiences, many issues need to be investigated in depth like how to determine reasonable working parameters, how to assess on the impact of waste discharge on the sea environment.