Keiji Miki

Liquefaction of iron-loaded subbituminous coal in the presence of a sulphur source

Abstract Dispersion of disposable iron as a catalyst precursor was investigated to improve the catalytic activity in the liquefaction of a subbituminous coal. Treatment in FeSO4 solution under vacuum conditions resulted in the incorporation of 0.25 and 0.33 wt% iron into the coal samples. Despite the low level of loading, the liquefaction of iron-loaded coal showed a significant increase in total conversion and oil yield in the presence of a sulphur source. Also the hydrogen consumption decreased with use of an iron-loaded catalyst. These facts suggest that the impregnation of iron is a beneficial method of enhancing the catalytic activity and reducing the amount required for the liquefaction process.

Fluid Catalytic Cracking of Coal Liquids (Part 2)

石炭液化油中質油留分の流動接触分解反応についてナフサおよび中質成分の収率ならびにコーク生成量に与える予備水素化処理の効果を実験的に検討した。試料としたカナダ産バトルリバー炭からの液化油中質油留分の水素化処理は, 通常の固定床流通反応装置によってNi-Mo/Al2O3触媒を用いて反応温度370°CおよびLHSV 1h-1の条件で水素圧を50, 100ならびに150kg/cm2•Gと変化させて行った。水素化処理油のH/C原子比は水素圧が高くなるに従って上昇し, 芳香族化合物の環水素化反応も前報で取り上げた重質油留分の場合よりも一層効果的に進行した。次に, 得られた水素化処理油について, ASTMに準じて設計された小型試験装置によって, スチーミング処理済のFCC触媒を使用して反応温度482°CおよびWHSV 16wt/wt/hの条件で接触分解反応を行った。予備水素化処理によって接触分解によるコーク生成量は1.3wt%まで減少し, また中質油留分の蒸留性状は大きく変化し, ナフサ成分の収率が2.5～5倍まで上昇するなど予備水素化処理を組み合わせることによって効果的に軽質化できることがわかった。また, 石炭液化油中に含まれているn-パラフィンならびに一環から三環までのシクロパラフィン, 部分水素化芳香族および芳香族化合物の中から主なものをモデル試料として選び, 接触分解反応を行って各々の化合物タイプによる反応性を検討した。

EFFECT OF IRON CATALYST ON THE COMPOSITION OF OIL FROM COAL LIQUEFACTION

ABSTRACT The effect of two iron catalysts, red mud and CGS S-G, as well as C0-Mo/AI2O3 and Ni-Mo/Al203 commercial catalysts on the composition of oil derived from the liquefaction of Japanese subbituminous coal have been investigated comparatively by conventional autoclave experiments at 440 and 450°C under initial hydrogen pressure of 85kg/cm2 G with tetralin to coal weight ratio of 3. From the results obtained at 450°C, total conversion and the yield of gas revealed almost same level with four catalysts, but the oil product from molybdenum catalysts showed higher yield than that from iron catalysts. CGS S-G catalyst also showed higher yield of oil product than red mud catalyst. Reaction behavior of two iron catalysts were also tested by solvent recycle mode experiments.

Purification of Polycyclic Aromatic Hydrocarbons in Coal Tar by using Pressure Induced Crystallization with Solvent.

To separate polycyclic aromatic hydrocarbons from coal tar, which have very high melting point and difficult to purify, the pressure induced crystallization method was modified to use solvent and it was applied to the separation of anthracene from model mixture and real anthracene cake. At the condition of 333K, 150MPa, high purity anthracene crystal with 99.1 wt% was recovered from the model mixture by this method. The purification of real anthracene cake was also achieved by this method, however, the purity of recovered anthracene crystal was slightly influenced by the minor compounds in real anthracene cake.

The Properties of Thermal Hydrodealkylation Products from Coal Liquids and Other Oils

石炭液化油等の化石資源から製造される重質油中には, 医薬品あるいは機能性高分子材料の原料として利用可能な特異な骨格構造を持つ化合物が数多く含まれている。しかし, 液化油は多様なアルキル芳香族化合物の混合物であり, 含有されるそれぞれの化合物の濃度は低い。そこでこれを脱アルキル反応によりいくつかのアルキル側鎖の少ない化合物に整理•濃縮することが分離•精製のための有効な手段と考えられる。本研究では, 前報に引き続きアルキルベンゼン類から高純度ベンゼンを生成する反応として知られている熱的水素化脱アルキル反応により, 石炭液化油を高濃度の単純な化合物に整理•濃縮する方法について検討した。また, コールタールや石油系のLCO等由来の異なる油についても同様の反応を行い, 原料による生成物性状の違いについて検討した。その結果, (1) 水素化脱アルキル反応により, これらの重質油の中の成分をいくつかの単純な芳香族骨格構造を有する化合物に整理•濃縮できることがわかった。(2) これらの油に特徴的な芳香族基本骨格構造はこの反応によってほとんど変化しない。(3) 油種の違いについては, 同じ石炭系重質油でも循環溶剤留分では常圧軽油留分には少ないアントラセン, フェナンスレン, ピレン等の3～4環芳香族が多く含まれること, 石炭液化油中に多いジベンゾフラン等の含酸素化合物は石油系のLCOでは見られない等, 油種により含有される化合物やその濃度は異なり, また脱アルキル反応温度により生成物中のナフタレンとメチルナフタレンの濃度比が異なることがわかった。したがって, 原料となる油の種類や分離目的とする化合物の種類等により, 反応条件の最適化が必要と考えられた。さらに, 石炭系重質油からの脱アルキル生成油中にはキノリン, インドール等の含窒素化合物が, 一方, 石油系重質油の場合にはベンゾチキオフェン等の硫黄化合物が検出され, 個々の芳香族炭化水素を精製する過程で不純物として混入する可能性が指摘できる。

Two stage liquefaction using bottom recycle. (I). The effect of hydrogenation catalyst at the first stage.

To investigate the feasibility of nondistillable bottom recycle for the enhancement of liquid yields, two stage liquefaction of Yallourn and Taiheiyo coals were conducted using NiMo/Al2O3 with red mud at the first stage.Over successive passes, high coal conversion (>96wt%) at the first stage was maintained, and yields of gas and THFI were not increased. It was also indicated that 60wt% of both coals were converted to cyclohexane solubles at the initial stage accompanied with the promoted conversion of coal and/or cyclohexane insolubles. The improvement of conversion and product selectivity seems to be related with the changes in quality of recycle solvent in terms of the efficiency of hydrogen transfer reaction, and with the removal of hetero compounds causing the regressive reaction.The above results suggest the possibility of highly efficient conversion of organics inherent in both brown and subbituminous coals to liquid products.

Study on the separation of hetero compounds in coal liquids.

Prefractionation of coal liquids into different types of chemical classes was performed by adsorption column chromatography using a mini pre-packed disposable column (Sep-Pak ALUMINA N Cartridge) instead of acid-base extraction. Model compounds could be separated into 4 fractions such as aliphatic hydrocarbons, polycyclic aromatic hydrocarbons, polycyclic aromatic nitrogen compounds and polycyclic phenolics.This technique was also applied to the heavy fraction of subbituminous coal liquids. The characterization of the nitrogen containing aromatic compounds was carried out by gas chromatography-mass spectrometry.Major components of nitrogen compounds are alkylated carbazoles, alkylated benzoquinolines, and alkylated benzocarbazoles. But polycyclic aromatic amines are not detected by our analytical procedure.

Evaluation of middle distillate derived from Battle River coal as diesel-powered automobile fuels from the point of exhaust emissions.

In order to evaluate the feasibility of coal derived middle distil-lates as diesel-powered automobile fuels, mass emission of CO, HC, NOx and particulate matter, and content of soluble organic fraction (SOF) in the particulate matter were measured by operating two types of automobiles fueled with the middle distillate under 10 mode driving cycle, idle condition and constant speed conditions at 20, 40 and 60km/h. One (A) of the automobiles was conformed to Japanese emission standard for indirect injection type dieselpowered lightduty vehicle in 1988 and the other (B) to standard for dieselpowered passenger car in 1986 which required more stringent permissible limit for NOx. The middle distillate (BHD) was obtained from liquefaction of Battle River coal followed by catalytic hydrogenation and distillation ranged from 180 to 350°C. Test fuels BHD-10 and BHD-25 were prepared by mixing 10 and 25vol% of the distillate (BHD) with the gas oil (F), respectively, and test fuel (BHD-25D) by adding 0.5vol% of a cetane booster to the fuel BHD-25.The mass emission of CO, HC and particulate matter emitted from the automobiles A and B increased with the increase of the middle distillate content in the test fuels, but the mass emission of NOx and the content of SOF did not correlate with the middle distillate content for either automobile. These results were almost the same as the results reported in a previous paper except for SOF. The emission from the automobile B showed stronger dependence on the middle distillate content than the other automobile, but the degree of dependence became very small compared with the previous results. Addition of the cetane booster to the mixed fuel improved the ignition quality, that is, the cetane number was raised from 44 to 53, and it decreased the mass emission of CO, HC and particulate matter in the case of automobile B.Although exhaust emission characteristics of the mixed fuel containing the coal derived middle distillate were highly improved by adding the cetane booster and distilling the middle distillate between 180 to 350°C, the improvement of the middle distillate itself, such as lowering of aromaticity, is necessary to use it under more stringent emission standard.