單點繫泊離岸天然氣儲存設施設計與分析

Abstract

由於環保政策的推廣，傳統發電廠使用天然氣替代燃煤發電、核電廠拆除等，使得台灣近年來對於天然氣的使用逐漸增長。根據能源局統計台灣對天然氣的消費量自1996年至2016年，年平均成長率為10.47%，而台灣天然氣主要是由國外進口，因此建設天然氣的儲存設施為現存的問題之一，近幾年本應在桃園大潭電廠旁建設台灣第三座天然氣接收終端站，由於環保的關係導致計劃無法順利執行。本論文提出在離岸建設一座天然氣終端站，目的在於遠離保育區、節省土地利用。 本論文主要分為三個部分，第一個部分為資料的蒐集，包含台灣能源使用、海上巨大浮體結構、陸上儲罐結構、LNG運輸船結構、繫泊系統、台灣海域地形等等，將以上資料納入本論文儲存設施設計之參考。第二部分為將儲罐需使用之相關資訊整理並設計出本論文儲罐結構，並利用COMSOL計算結構是否具有絕熱效果，同時利用經驗公式配合假設條件計算本設計所受之環境力並估計所需之錨定力。第三部分透過蒐集到的海岸地形圖，評估此設施是否能建設在台灣離岸並做一個簡單的區域規劃。 結論中，本設計之絕熱效果在天然氣使用週期(15天)內具有相當好的表現，而在環境力的部分計算值與線有LNG運輸船或其他油輪的錨定力相去不遠，因此本設施可錨定在海床上不致偏移。 此論文僅設計一個簡單之結構，並不包含氣化設備以及運輸管線配置、施工方法，而在計算部分並未考慮此設施位於海上是否會處於平穩狀態不致傾倒，僅提供一個解決現有問題的方案。

Due to the promotion of environmental protection policies, traditional power plants use natural gas to replace coal-fired power generation, the demolition of nuclear power plant, etc., making Taiwan's use of natural gas gradually increase in recent years. According to the statistics of the Energy Bureau, Taiwan’s consumption of natural gas has averaged 10.47% annual growth rate from 1996 to 2016, and natural gas in Taiwan is mainly imported from abroad, the construction of natural gas storage facilities is one of the existing problems. Recent years, the third natural gas receiving terminal station in Taiwan should be built next to the Taoyuan Datan Power Plant, due to environmental protection, the plant cannot be implemented smoothly. This paper proposes to build a natural gas terminal station offshore to separate it from the conservation area and to save land use. This paper is divided into three parts. The first part is the collection of data, including the use of energy in Taiwan, the huge floating structure on the sea, the onshore storage tank structure, the LNG carrier structure, the mooring system, the terrain of Taiwan's sea areas, and so on. The above information is incorporated into the design of the storage facility of this paper. The second part is to organize and design the storage tank structure of this paper by using the relevant information needed for storage tanks, and use COMSOL to calculate whether the structure has adiabatic effect. At the same time, using empirical formulas and assumptions to calculate the environmental forces on the design and estimates the anchoring force. The third part assesses whether the facility can be built offshore in Taiwan and make a simple regional plan through the collected topographic maps of the coast. In conclusion, the adiabatic effect of this design has a fairly good performance within the life cycle of natural gas (15 days), and the calculated value of the environmental force is not far from the value of the anchorage force of the LNG carrier or other tanker. Therefore, the facility can be anchored on the sea floor without deflection. This paper only designs a simple structure that does not include gasification equipment and transportation pipeline configuration and construction methods. However, in the calculation part, it does not consider whether the facility will not be dumped on the sea. It only provides a solution to the existing problems.