逆流式水泥旋轉窯三維燃燒流場之廢熱回收於燃料電池之應用可能性分析

Abstract

本文提出一全新的技術觀念：利用目前現存之旋轉窯熱流場提供固態氧化燃料電池（SOLID OXIDE FUEL CELL, SOFC）所需之高溫操作環境。現今的新型管式SOFC設計 (TSOFC) 更適合於旋轉窯之安裝與操作，為數種燃料電池中最為適與汽電共生或與焚化爐結合的類型。 故本文以其為研究對象，合理地假設並評估其安裝的可行性，並發現妥善安排的燃料電池模組共可產出達39.59MW的電能。 本實驗並採用計算流體力學軟體FLUENT之有限體積分析法解工業用旋轉窯焚化爐窯體內之熱流場、向量場、與物質反應的偏微分方程式，以反應操作模式中燃燒所需之過剩空氣量與溫度、旋轉爐之旋轉速度為主要參數，模擬燃燒氣體熱流場與旋轉窯壁之熱傳模式。模擬結果與實際現場量測所得之溫度數值作相互比對，以進行各不同之燃燒反應參數在流場顯影之探討，最後並依照其燃燒熱流場及窯壁內部溫度之分佈預測，進行固態氧化物燃料電池於旋轉窯爐床安裝之可行性探討。

When meeting the shortage of fossil fuels and the coming era of hydrogen energy, fuel cell energy emerged to be a promising technology in energy utilization in the future. Developed to work at 800 to 1,000 degree Celsiusand and up to 15 atm (tested by Ontario Hydro Technology), solid oxide fuel cells (SOFCs) can generate the maximum power output among all types of fuel cells. However, when operating the SOFCs, great amount of fossil fuel is actually consumed in order to meet their high-temperature demand. High amount of secondary pollutants are expelled accordingly. A possible brand new idea is thus proposed in this paper—a state-of-the-art tubular SOFC (TSOFC) can be installed either in the three dimensional heat flow field inside the cement industrial rotary kiln incinerator (RKI, located in Kaohsiung, Taiwan) or within its refractory layer where high temperature environment sustains around the clock when operating for the cement production. In this paper, simulation of the heat flow field and species remained after combustion in this kiln incinerator is achieved with the help of modern computer aided engineering (CAE) tool. Suitable manipulating regions are to be found and predicted via the commercially available CFD code FLUENT. Parameter of excess air values are the primary variable, the detailed interior heat flow field and the heat transfer model in the kiln shell are the secondary variables for evaluating the installation of SOFCs into rotary kilns. Before going on this study, kinetic parameters are parametrically varied and finite volume method (FVM) is introduced to solve the heat flow field and the visualization of the three dimensional flame structure is performed. Meanwhile, simulation of temperature results is compared with on-site field experiments and the installation possibilities of the SOFC on the rotary kiln incinerator can be reasonably predicted and assured