For the calorimeter which controls temperature of an adiabatic jacket by injection of hot water, a sampled-data control system is considered as an available method to control the temperature precisely. The control action is accomplished periodically and the opening time of the injection valve for hot water is regulated at every period so that the manipulated variable of the control system can be variable and the superior control law to the on-off control one which is usually used for the hot water method can be applied. In order to prove the availability of this method, the PID control law is applied and its control characteristics is compared with the on-off control system. The results are as follows. The shorter the sampling period becomes, the smoother the variation of the temperature of the jacket becomes but the longer the time constant of the heating system becomes. Therefore there is the most suitable value for the sampling period and that depends on the equipment of the jacket. The relation between the temperature rise of the jacket and the opening time of the injection valve can be nearly represented by a linear function. The PID control system using this relation and some manipulation on the software can offer better control characteristics than those by usual system. In other words, better control characteristics can be obtained by the periodical control action of the injection valve.
Quinoline could be carbonized at 300-450°C using of ZrCl4 as the carbonization promoter. The carbonization reaction path of quinoline, changes of Zr left in carbonized products by high temperature treatments up to 2500°C and the oxidation of carbonized and graphitized products (powder) in air have been studied. The formation of a complex between quinoline and ZrCl4 and the analyses of Tetrahydrofuran-solubles in carbonized products led to the conclusion that the carbonization reaction of quinoline is a kind of additional polycondensation of the quinoline molecules, in which complexes formed between ZrCl4 and quinoline act as reaction intermediates and the hydrogen atoms unbound move to other parts of molecules to produce hydroaromatic rings, followed by partial rupturing and isomerization of the hydroaromatic rings formed. ZrCl4, added as a carbonization promoter, was left mainly as loose ZrO2 crystals in carbonized products, which developed into rigid crystals by treatments up to 1500°C and changed to ZrC crystals at higher temperature treatments of 2000-2500°C: ZrO2/C composites were formed at up to 1500°C and ZrC/C composites at 2000-2500°C. The carbonized products from quinoline were graphitized by as the heat treatment temperatures rised. The reactivity in air of ZrC/C composites formed at higher than 2000°C was almost the same as that of a mixture of ZrC and C, and that of the parent carbon material decreased with the growth of the graphite structure by an increase in the heat treatment temperatures. Similarly, the parent carbon in ZrO2/C composites showed a graduall decrease in reactivity for oxidation with an increase in the heat treatment temperatures, though more reactive than ZrC/C composites.
Twelve kinds of coal ranging from 66.1 to 89.5%daf of carbon content were rapidly pyrolyzed in a free-fall pyrolyzer at atmospheric pressure under nitrogen, at temperatures up to 980°C and heating rates of 4000-6000°C/s. The results show that another parameter is necessary to correlate the extent of organic sulfur removal from solid phase in addition to the carbon content. The extent of organic sulfur removal changed depending on the samples ranging from 70 to 80% of carbon content, and the difference of more than 30% was observed for the same carbon content samples: PSOC830 and Muswell Brook. Sequential changes were observed in the sulfur form distribution of gravity concentrated samples having different contents of maceral group during rapid pyrolysis. The low specific gravity samples concentrated exinite and vitrinite. The release rate of organic sulfur from the solid phase increased linearly with the contents of exinite and vitrinite though the slope depended on the raw coals. The extents of organic sulfur removal also increased with the contents of exinite and vitrinite. The maceral group played an important role on the release of organic sulfur from the solid phase during rapidpyrolysis.