Katsuya Koguchi

Liquid fuel production from sewage sludge by catalytic conversion using sodium carbonate

Abstract For the production of liquid fuels and as a means of pollution control, sewage sludge was directly converted into heavy oils. The sewage sludge, having a moisture content of 75 wt %, was heated under pressurized nitrogen over the temperature range 250–340 °C in the presence of sodium carbonate. The yields and properties of the heavy oil produced depended strongly on the catalyst loading and reaction temperature. Liquid fuels having heating values of ≈ 33 MJ kg − 1 were obtained in 50 wt % yields on an organic basis. The energy balance of this liquefaction process is briefly discussed.

DIRECT LIQUEFACTION OF WOOD BY CATALYST AND WATER

ABSTRACT Wood powder suspended in water was directly liquefied in the presence of nickel carbonate or potassium carbonate without a reducing agent like hydrogen and/or carbon monoxide. Heavy oils with carbon and hydrogen contents of about 80% were produced and their heats of combustion ranged from 29.3 to 33.4 MJ/kg. Total carbon recovery in the form of heavy oils was about 24%.

Direct liquefaction of activated sludge from aerobic treatment of effluents from the cornstarch industry.

Abstract Activated sludge from a cornstarch processing plant, a by-product of biological wastewater treatment, was converted directly into heavy oil by mixing with sodium carbonate of up to 20 wt%, and heating to temperatures ranging between 225 and 340°C with holding times of up to 120 min under a pressurized nitrogen atmosphere. Liquefaction was accomplished without a catalyst. The yields were influenced by the temperature and holding time. Heavy oil with heating value of 32 MJ kg−1 was obtained with 30 wt% yield on a moisture- and ash-free basis at a temperature of 300°C and holding time of 60 min. The energy balance for this liquefaction process was estimated.

A new treatment of sewage sludge by direct thermochemical liquefaction.

As one economical solution to the sludge disposal problem, the thermo-chemical conversion of sewage sludge to heavy oil was studied. In order to investigate optimum starting materials and catalyst loading for this conversion, various kinds of sewage sludge were liquefied at a temperature of 300°C, at a pressure of 12 MPa, and a catalyst (sodium carbonate) loading of 0–20wt% using a batch-type reactor. As a result, the optimum kind of sewage sludge was either raw primary sludge or raw sludge containing a mixture of primary and waste activated sludge because the average oil yields of these sludges reached to 43% and were higher than those of other kinds of sludges. Regarding catalyst loading, for most of sewage sludge, oil production proceeded satisfactorily without adding any catalyst by the catalytic action of inorganic components in sewage sludge. This can lead to not only cheaper operating costs, but also to the reduction of initial investments. Energy balance of this conversion was briefly discussed.

Liquid Fuel Production from Ethanol Fermentation Stillage by Thermochemical Conversion

Ethanol fermentation stillage, which is an aqueous organic waste inevitably co-produced from the fermentation process of various biomass was converted to a liquid product thermochemically. Since the moisture content of the stillage was 95–98%, it was dewatered to 70–80% m.c. Such dewatered stillage from various kinds of biomass such as sweet potatoes, barley, and rice were treated with sodium carbonate under high pressure and temperature using a batch-type reactor. Though they contained 1–6% nitrogen, the yields of product heavy oils were from 30 to 50%, depending on the variety of starting materials. The heating value of heavy oil was about 35 MJ/kg. From an estimate of energy balance, this process was found to be a net energy producer.

Production of Heavy Aromatic Hydrocarbons by Catalytic Reforming (Part 3)

Studies were carried out to investigate the composition of C6-C10 alkylbenzenes and C10-C12 alkylnaphthalenes in reformate and the yield of aromatics which were obtained by catalytic reforming of kerosene, using the commercial platinum-alumina reforming catalyst.1) Kerosene fractions having the boiling range of 210∼220°C, 220∼230°C, 230∼240°C, 240∼250°C and 250∼260°C obtained from Gach Saran crude oil were reformed.Kerosenes having boiling ranges of 210∼220°C, 230∼240°C and 250∼260°C gave higher yields (crude oil basis) of aromatics. Naphthalenes contents in reformates increased with raising of boiling point of the feed. However, compositions of C8, C9 and C10 aromatic isomers remained unchanged regardless of the boiling range of kerosene fractions.2) Gach Saran kerosene (180∼250°C) was reformed using the operating conditions as follows; the temperature 450∼530°C, the pressure 10∼50atm, the liquid hourly space velocity 0.6-8.4 and the mole ratio of hydrogen to hydrocarbon 5-15. From the data obtained, the relationship between the operating conditions and the yield, compositions of aromatics in reformates were investigated.3) Kerosenes of Gach Saran, North Sumatra, and Ekhabinskaya, having the boiling range of 180∼250°C and C10-C12 n-paraffins were reformed.The yields of reformates and the aromatics in reformates obtained from kerosenes varied with the kind of feed, but the compositions of aromatic isomers did not change with the feed.The yields of aromatics in reformates obtained from C10, C11 and C12 n-paraffins showed almost the same values, and compositions of aromatic isomers agreed with each other. Generally, C8-C10 aromatic isomers in the reformates obtained from C10-C12 n-paraffins contained more poly-methylbenzenes, and less mono-alkylbenzenes and alkylindanes than those obtained from kerosenes. From the above results, main pathway of dehydrocyclization of C10-C12 n-paraffins using the acidic platinum-alumina catalyst seems to be formed through iso-paraffin.

Solubilities of Durene and Isodurene at Low Temperature

ジュレンの結晶化分離に関連し,低温におけるジュレンおよびイソジュレンの溶解度を明らかにした。すなわちジュレンと沸点の接近しているC10,C11 芳香族多成分系におけるこれらの溶解度は融点法および飽和溶液の組成分析により測定した。C 1 1 芳香族の濃度が22%以下の場合, 0～-60℃の範囲内でC10,C11芳香族多成分系におけるジュレンの溶解度は次式で与えられる。logN=0.01352T-4.576N:T°Kにおけるジュレンの溶解度( モル分率)一方, イソジュレンの溶解度曲線は系の成分により異なる。低温におけるジュレンおよびイソジュレンの溶解度の測定結果から,原料の組成と第2次析出点との関係を明らかにした。テトラメチルベンゼン三成分系におけるそれぞれの二成分共融点および三成分共融点は次のとおりである。共融温度共融点の組成ジュレン-イソジュレソ-26.6℃ ジュレン5.7%,イソジュレン94.3%ジュレン-プレニテン-11.3℃ ジュレン9.2%,プレニテン90.8%イソジュレンープレニテン-442℃イソジュレン56.0%,プレニテン44.0%ジュレンーイソジュレソープレニテン-46.5 ℃ ジュレン3.1%,イソジュレン53.7%,プレニテン43.2%上述のテトラメチルベンゼン三成分系における溶解度および共融点の組成から三成分系固液平衡図を作成した。

The Supersolubilities of Durene in Multicomponent Systems of C10and C11Aromatics

ジュレンと沸点の接近しているC10,C11芳香族多成分系溶液におけるジュレンの過飽和溶解度(主として第2過飽和溶解度)と操作条件との関係について検討した。冷却水の温度および流量は溶液の冷却速度に影響し,冷却速度が大きくなると過飽和溶解度は急激に大きくなり,やがて一定値を示す。かきまぜ速度を大きくすると過飽和溶解度は小さくなる。これは生成した微細な結晶がかきまぜ翼により破壌され結晶核が多量に生成するためである。種晶の少量の添加により過飽和溶解度は急激に小さくなるが,種晶の添加量が0.1wt%以上では過飽和溶解度の減少率は小さい。ジュレンの濃度の減少により温度過飽和度は大きくなるが,それぞれの濃度において操作条件により影響されない限界値がある。この限界値を限界過飽和溶解度とすると,この値はジュレンの濃度いかんにかかわらずジュレンの結晶析出率が約10%になるような位置にあり,これらを結んだ限界過飽和溶解度曲線は1本の曲線で示される。

The Solubilities of Durene in Multiplecomponent Systems of C10, C11 Aromatics

高分子原料として有望なジュレンを,石油芳香族留分から結晶化分離するための基礎資料を得る目的で,ジュレンと沸点の接近しているC10あるいはC11芳香族とジュレンとの二成分系およびC10,C11芳香族多成分系におけるジュレンの溶解度を測定した。その結果,次のことが明らかになった。1)C10あるいはC11芳香族とジュレンとの二成分系におけるジュレンの溶解度はそれぞれ図1の1本の曲線で表わされ,またC10,C11芳香族多成分系におけるジュレンの溶解度はその組成の如何にかかわらず図1の2曲線の範囲内にある。2)C10,C11芳香族多成分系においてC11芳香族の濃度が22mol%以下ではC11芳香族の濃度如何にかかわらずジュレンの溶解度はC10芳香族の溶解度曲線で表わせ, C11 芳香族の濃度が22mol%以上になるとC11 芳香族の濃度増加に対して直線的に減少する。3)これらのC10あるいはC11芳香族とジュレンとの二成分系は近似的に理想溶液と考えることができ,共融混合物を形成する。