• Clean Technology
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• v.16 no.3
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• pp.198-205
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• 2010

Two sets of thermal reaction experiment for chlorinated hydrocarbons were performed using an isothermal tubular-flow reactor in order to investigate thermal decomposition, including product distribution of chlorinated hydrocarbons. The effects of $H_2$ or Ar as the reaction atmosphere on the thermal decomposition and product distribution for dichloromethane($CH_2Cl_2$) was examined. The experimental results showed that higher conversion of $CH_2Cl_2$ was obtained under $H_2$ atmosphere than under Ar atmosphere. This phenomenon indicates that reactive-gas $H_2$ reaction atmosphere was found to accelerate $CH_2Cl_2$ decomposition. The $H_2$ plays a key role in acceleration of $CH_2Cl_2$ decomposition and formation of dechlorinated light hydrocarbons, while reducing PAH and soot formation through hydrodechlorination process. It was also observed that $CH_3Cl,\;CH_4,\;C_2H_6,\;C_2H_4$ and HCl in $CH_2Cl_2/H_2$ reaction system were the major products with some minor products including chloroethylenes. The $CH_2Cl_2$/Ar reaction system gives poor carbon material balance above reaction temperature of $750^{\circ}C$. Chloroethylenes and soot were found to be the major products and small amounts of $CH_3Cl$ and $C_2H_2$ were formed above $750^{\circ}C$ in $CH_2Cl_2$/Ar. The thermal decomposition reactions of chloroform($CHCl_3$) with argon reaction atmosphere in the absence or the presence of $CH_4$ were carried out using the same tubular flow reactor. The slower $CH_3Cl$ decay occurred when $CH_4$ was added to $CH_3Cl$/Ar reaction system. This is because :$CCl_2$ diradicals that had been produced from $CHCl_3$ unimolecular dissociation reacted with $CH_4$. It appears that the added $CH_4$ worked as the :$CCl_2$ scavenger in the $CHCl_3$ decomposition process. The product distributions for $CHCl_3$ pyrolysis under argon bath gas were distinctly different for the two cases: one with $CH_4$ and the other without $CH_4$. The important pyrolytic reaction pathways to describe the important features of reagent decay and intermediate product distributions, based upon thermochemistry and kinetic principles, were proposed in this study.

• Korean Journal of Agricultural Science
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• v.9 no.2
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• pp.546-555
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• 1982

To evaluate the digestibility and absorbability of proteins, and the rates of energy and nitrogen(N) metabolism of the Korean native goats, studies were carried out with open type respiration apparatus based on the nitrogen-carbon method. The results on the nitrogen retention and the metabolic rate of energy, which was obtained with one male (10-month-old) and one female (24-month-old) goats, both weighing ${\simeq}20kg$, are summarized as follows. 1. When the goats were fed ad libitum the medium quality orchard grass hay, they consumed hay about 0.66 to 0.92% of body weight per day. The hay intake was remained the same even when high quality hay was provided. This amount of hay intake was relatively lower than that of dairy goat and sheep. It was believed to be partly due to the change in feeding enviroment. When fed with hay and soybean meal together, the goats ate hay about 1.06% and soybean meal about 0.60% of body weight, corresponding to 1.66% of body weight as fed basis. 2. The $CO_2$ gas produced from the goat in the open type respiration chamber and absorbed with KOH solution was estimated to be 99~117g/day. The difference in feed intake did not influence the $CO_2$ production; however, these seems to be a linea relationship between body weight and $CO_2$ production. 3. When fed orchard grass hay only, the goats showed protein digestibility of 24~41%. The protein digestibility incresed to 58.2% when fed hay and soybean meal together. A negative nitrogen balance(-0.16g N/day) was observed with goats fed 11.53g N originated from 212g hay and 150g soybean meal. Converting that nitrogen ingested to a crude protein, the amount of crude protein intake by the goats per day was 77.9g compared to 40~45g N known to be required in a day by goat weighing 20kg, indicating that the extra protein ingested was metabolized to provide energy. 4. When the male and female goats comsumed 624 kcal gross energy and 824 kcal gross energy by consuming 158g and 213g of hay, respectively, the digestible energy intake was calculated to be 260kcal for the male and 199kcal for the female goat. The daily heat production of male and female goats were 338kcal and 334kcal, respectively, when fed hay only. However, the female goat fed 212g hay and 150g soybean meal produced about 591kcal per day. Consequently, the energy requirment of the Korean native goats weighing ${\simeq}20kg$ was concluded to be $${\geq_-}$$600kcal net energy per day. 5. The fasting heat product ion of a male goat weighing 27.7kg was 412kcal per day when fasted for 2~3 days. When fasted for 3~4 days, the value decresed to 240kcal. The enviromental temperatures during the expreimental period were ranged from 19 to $34.5^{\circ}C$. The goats seemed to be panting when the chamber temperature rose to $32^{\circ}C$ or above. 6. When fed low levels of dietary protein, serum protein levels of the goats were decresed slightly ($${\leq_-}$$10%); however, urea content in the serum was observed to decrese to a great extent (3X).