Shin-ya Yokoyama

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%.

Catalytic reduction of carbon dioxide. 1. Reduction of carbon dioxide with carbon carrying potassium carbonate

Abstract The catalytic behaviour of potassium carbonate doped onto active carbon was investigated with respect to reduction of carbon dioxide. The distribution of potassium on the carbon surface was found by an X-ray microanalyzer to be uniform. The amount of oxygen trapped on the carbon surface during reaction was nearly proportional to the surface concentration of potassium. The catalytic activity with carbon doped with less than 2% potassium carbonate was proportional to the amount of trapped oxygen, while excessive doping by potassium was found to form trapped oxygen independently of the gasification of carbon. Disproportionation of carbon monoxide into carbon dioxide and carbon was found to take place readily at 700 °C, with carbon doped with 4.0 wt % potassium carbonate.

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.

Evidence for totally intramolecular hydrogen transfer type double bond isomerization on carbon doped with potassium carbonate

Co-isomerization of [2Ho]- and [2H8]-cis-but-2-ene led to preferential formation of [2Ho]- and [2H8]-but-1-ene respectively, which provides evidence for intramolecular hydrogen transfer via a π-allyl anion over potassium carbonate-doped carbon.

Accumulation of potassium oxide on carbon and enhancement of catalytic activity for isomerization by O2

The concentration of potassium oxide on a carbon surface is changed by contact with oxygen at room temperature resulting in a marked enhancement in catalytic activity for the isomerization of but-1-ene to cis-but-2-ene.