Catalytic and thermal degradation of waste expandable polystyrene (WEPS) have been studied in a semi-batch reactor with continuous flow of nitrogen to achieve greater oil yield and maximize styrene monomer recovery. Effect of temperature, nature of catalyst and its size, reaction time of catalytic pyrolysis, and effect of repyrolysis have been also investigated. Higher reaction temperature favors the oil yield and also decreases the reaction time with maximum styrene selectivity (76.31 wt %) at 450 °C. Among the catalysts studied, solid base BaO is found to be the most efficient and increases the styrene selectivity (84.29 wt %) significantly at a reaction temperature of 350 °C in comparison to thermal and acid catalytic degradation. Modified catalyst Fe−A/Al (A = basic material) also shows better activity than Fe2O3 or Fe/Al. Increase in the size of the catalyst and repyrolysis decrease the oil yield, and styrene production also decreases on repyrolysis.

Objective This study was conducted to evaluate the effects of feed processing and particle size on growth performance, nutrient digestibility, carcass characteristics, and gastric health in growing-finishing pigs. Methods A total of 360 growing pigs (22.64±0.014 kg initial body weight [BW]) were allocated to 1 of 6 treatments with 6 replicates by BW and sex, and 10 pigs were housed in one pen in a randomized complete block design. The BW and feed intake were recorded to calculate growth performance. For the digestibility trial, a total of 24 barrows with an initial BW of 33.65±0.372 kg were split into 6 treatments with a completely randomized design. Dietary treatments were designed by a 2×3 factorial arrangement of treatments based on two main factors, particle size (600, 750, 900 μm) and feed form (mash and pellet) of diet. Experimental diets were formulated to contain the requirements of the NRC (2012). Results The BW and average daily gain were not changed by dietary treatments, and the feed intake of finishing pigs (wks 6 to 12) was increased when the pigs were fed a mash diet (p<0.05). For the overall period, the feed efficiency of pigs was improved with the pellet diet (p<0.01) and reduced particle size (p<0.05). The pellet diet had effects on increasing crude fat digestibility (p<0.01) relative to a mash diet, but there was no considerable change in dry matter and crude protein digestibilities by dietary treatments. In the evaluation of gastric health, a trend for an increased incidence of keratinization in the esophageal region was observed as particle size decreased (p = 0.07). Conclusion Feed efficiency could be improved by pellet diet and reduced particle size. Nutrient digestibility, carcass characteristics, and gastric health were not affected by feed form, and particle size ranged from 600 to 900 μm.

This study investigates the applicability of the bubble column as a reactor to perform the dehydration of ortho‐boric acid efficiently and economically. The effects of operating conditions such as reaction time, temperature, gas flow rate, particle size and solid content in the slurry phase on the fractional conversion of the reaction have been determined, and the performance of the three‐phase bubble column reactor operating at low pressure (92 kPa) has been discussed. It can be noted from this study that the reaction time has been reduced and the particle size and solid content which are required in the slurry phase for favourable fractional conversion have been increased in the bubble column reactor in comparison with those in the continuous stirred tank reactor. The reaction could be described by means of a fluid–solid heterogeneous reaction model.

No abstract

The characteristics of bubble properties and the chaotic fl ow behavior of gas were investigated in an annular fl uidized bed (0.102 m in inner diameter and 2 m in height) because the behavior of gas fl ow in such a reactor is one of the important factors governing reactor operation, reactor performance, and the reaction itself. Pressure fl uctuations as a state variable for the analysis of gas fl ow behavior were measured and analyzed. Bubble properties were determined by adopting the cross-correlation function of pressure fl uctuations. The resultant chaotic fl ow behavior of gas was interpreted by means of chaotic parameters such as the Kolmogorov entropy. It was found that the Kolmogorov entropy could be utilized effectively to explain the nonlinear dynamic behavior of gas-solid fl ow in the annular fl uidized bed. The pierced length and rising velocity of bubbles increased with increasing gas velocity, bed temperature, and particle size of the bed material. The bubble frequency increased with increasing gas velocity and bed temperature, while it decreased with increasing particle size of the bed material. Correlations to predict the bubble properties in annular fl uidized-bed reactors were suggested.