雙循環發電技術在地熱發電之應用

The Application of Two-circulation Generation Technique on the Geothermal Generation

柯經緯(Jing-Wei Ko) ； 陳萬容(Wan-Rong Chen) ； 蔡銘璋(Ming-Chang Tsai) ； 洪正宗(Cheng-Tsung Hong) ； 張錦澤(Jin-Tze Chang) ； 沈俊卿(Jiun-Ching Shen) ； 陳大麟(Da-Lin Chen) ； 胡興台(Shing-Tai Hu)

《石油季刊》 48卷4期 (2012/12) Pp. 51-64

https://doi.org/10.30128/JP.201212.0007

摘要

地熱可以直接使用或用來發電，靠近地表之熱水可直接加熱建築物、溫室、魚池，乾燥穀物等；地熱發電係使用地下逸出之水蒸氣直接推動汽輪機發電，或使用地下逸出之熱水經閃蒸（Flash）後之水蒸氣推動汽輪機發電，或使用地下逸出之熱水經換熱器使工作流體汽化成蒸汽推動汽輪機發電。工作流體係使用低沸點的物質（如：丁烷、氨、氟氯烷等），工作流體可循環使用，即使地熱水含有具有腐蝕性或結垢物質，只會影響地熱水管線與熱交換器而不影響汽輪機發電設備。清水地熱區第19號井之溫泉在地面管口之壓力為7.5 Kgf/cm^2G，溫度155～160 ℃，流量35 tons/hr（工研院估），本文採用雙循環式發電技術評估發電量與效率。工作流體之種類、工作流體之操作壓力與工作流體冷凝溫度，皆會影響發電量與實際熱效率；本文工作流體選用NH3、R22、R134、R245，進入汽輪壓力分別為45 Kgf/cm^2G 與40 Kgf/cm^2G，冷凝器之冷卻介質分別採用水與空氣進行模擬，模擬結果顯示R134實際熱效率最高，R245次之。再以工作流體進入汽輪機之溫度皆為141℃，冷凝器之冷卻介質分別採用水與空氣進行模擬，模擬結果顯示R134實際熱效率最高，R22次之。

關鍵字

地熱 ； 發電 ； 汽輪機

並列摘要

Geothermal energy can be utilized by the direct-use of applications or electricity generation. Hot water near the surface of Earth can be used directly for heat. The direct-use of applications include heating buildings, growing plants in greenhouses, heating water at fish farms, drying crops etc. Some geothermal power plants use the steam from the underground to spin a turbine/generator, by flashing the hot water from the underground to generate steam to spin a turbine/generator, or by using the hot water to boil a working fluid that vaporizes and then spin a turbine/generator. The working fluids could be some low boiling point materials, such as butane, ammonia and freon. The working fluids could be re-circulated. Even if the hot water contains corrosive materials or fouling materials, it will only influence the hot water pipelines and heat exchanger without influencing the turbine and the electricity generating equipment.The pressure and temperature of the hot water of Cing-shuei No.19 well is 7.5 Kgf/cm^2G and 155~160℃ at the ground. The flow rate of the hot water is 35 tons/hr (ITRI estimation). In this study, we have utilized the two-circulation generation technique to evaluate the power generation and actual thermal efficiency. It is indicated that the different kinds of the working fluids, including the operation pressure of the working fluids and the condense temperature of the working fluids will affect the power generation and actual thermal efficiency. We selected ammonia, R22, R134, and R245 as the working fluids for simulation, each entered the turbine under the pressures of 45 Kgf/cm^2G and 40 Kgf/cm^2G, then using cooling mediums of the condenser water and air, respectively. The results showed that R134 had the highest thermal efficiency and R245 had the second highest. When each working fluids entered the turbine at 141℃, the result revealed that R134 still had the highest efficiency and R22 had the second highest.

並列關鍵字

Geothermal Energy ； Generation ； Turbine