以連續式觸媒填充床系統氫化裂解桐油產製生質油品

Abstract

為了因應能源的日漸匱乏與氣候變遷造成的損害，生質油品成為近代備受矚目之再生能源。本研究利用自行合成之鉬基碳化物(Mo2C)披覆於活性氧化鋁(γ-Al2O3)顆粒表面之觸媒，以航空用油作為改質目標，於高溫高壓下氫化裂解桐油產製生質油品。 研究中以觸媒填充床搭配各項操作參數(溫度、氫氣流量、氫氣分壓、空間流速)進行桐油的氫化裂解改質實驗。根據各項操作參數產製之生質油品產率、特性(酸價、碘價、密度、熱值、氫含量、氧含量、碳數分布)，找出最適之操作條件。本研究先於溫度參數中找出最適之溫度條件，再進行下一最適操作參數探討之實驗，接序探討的順序為氫氣流量、氫氣分壓、空間流速。得到最適之操作條件後，再將工作氣體由H2改為N2以證明產製之生質油品品質並非單純之裂解就可達到。 結果顯示，溫度723 K、氫氣流量250 sccm、氫氣分壓50 psig、觸媒量25 g為最適之操作條件。其產製之生質油品於碘價、熱值、氧含量皆可達到目標油品之品質，產率還能維持在50 vol%以上；不能達到標準的酸價、密度、氫含量也與標準相差不多；且碳數分布與航空用油接近。於GC-MS分析中偵測出豐富的直鏈狀烷類。上述結果證實鉬基碳化物觸媒為有效之氫化反應觸媒。 本研究於最適條件下產製之生質油品品質接近航空用油，未達標準之酸價、密度、氫含量可以藉由與航空用油摻配的方式進行改善。

In order to solve for the problems of lack of energy and the disasters by climate change, the bio-fuel has recently become a notable renewable energy. This study synthesized the Mo2C/γ-Al2O3 catalyst and applied it for the hydro-cracking of tung oil via the continuous flow process to produce the bio-fuel which could substitute the aviation fuel. The hydro-cracking was carried out in a fixed catalytic bed. Key system variables were examined to find out the proper operating conditions. These included cracking temperature (TC), flow rate of hydrogen (QG), pressure of hydrogen (PH2), and amount of catalyst (mC). Comparison of using working gases of H2 and N2 was made to elucidate the role of H2. Properties of product of bio-fuel measured included acid value (AV), iodine value (IV), density (ρLO), heating value (HV), contents of hydrogen (MH) and oxygen (MO), and distribution of carbon numbers. Following the sequence of testing on TC, QG, pH2, and mC, the proper operation conditions were determined as 723 K, 250 sccm, 50 psig, and 25 g, respectively. The IV, HV, and MO of bio-fuel thus produced were satisfied with those of standards of aviation fuel Jet A-1. The AV, ρLO, and MH of bio-fuel could not meet the standards of Jet A-1, however, with small differences only. These small deficits can be resolved by blending an acceptable portion of bio-fuel with the Jet A-1. The distribution of carbon numbers of bio-fuel was close to that of Jet A-1. Further, the results of GC-MS analysis showed the bio-fuel was rich in linear alkanes, supporting that the catalytic hydro-cracking is effective.