Jonathan Wilson

Ultrasonic-Vibration Assisted Pelleting for Cellulosic Ethanol Manufacturing: An Experimental Investigation of Power Consumption

Ethanol produced from cellulosic biomass is an alternative to petroleum-based transportation fuels. However, its manufacturing costs are too high for cellulosic ethanol to be competitive. Cellulosic feedstocks have low density, causing their transportation and storage expensive, contributing to high manufacturing costs of cellulosic ethanol. Pelleting can increase the density of cellulosic feedstocks and reduce their transportation and storage costs. Ultrasonic vibration-assisted (UV-A) pelleting is a new pelleting method. Effects of input pelleting parameters (ultrasonic power, pelleting pressure, and particle size) on pellet quality and sugar yield have been studied. However, the effects of these parameters on power consumption in UV-A pelleting have not been studied. Since power consumption directly affects ethanol manufacturing costs, lower power consumption is desirable. The objective of this paper is to study effects of different input parameters (biomass material, particle size, ultrasonic power, and pelleting pressure) of UV-A pelleting on power consumption. Four types of biomass materials (big bluestem, corn stover, sorghum stalk, and wheat straw) were studied. Sorghum stalk consumed the least power. Pelleting pressure, particle size and ultrasonic power significantly affected power consumption of all four materials. Higher ultrasonic power and pelleting pressure resulted in lower power consumption. In addition, this paper also compares power consumption between UV-A pelleting and ring-die pelleting (a traditional pelleting method).© 2011 ASME

An Experimental Comparison of Two Pelleting Methods for Cellulosic Ethanol Manufacturing

Ethanol produced from cellulosic biomass is an alternative to petroleum-based transportation fuels. However, manufacturing costs of cellulosic ethanol are too high to be competitive. Low density of cellulosic feedstocks increases their handling and transportation costs, contributing to high overall costs of cellulosic ethanol manufacturing. Pelleting can increase density of cellulosic feedstocks, reduce transportation and storage costs, and make cellulosic ethanol production more competitive. UV-A (ultrasonic vibration-assisted) pelleting is a new pelleting method (available only in lab scale now). Preliminary research showed that UV-A pelleting could significantly increase pellet density and pellet durability but it has never been compared with other pelleting methods (e.g., using an extruder, a briquetting press or a ring-die pelleting). The objectives of this research are to compare UV-A pelleting with ring-die pelleting in terms of pellet density, pellet durability, energy consumptions of pelleting. The results will be useful to find a better pelleting method for cellulosic ethanol manufacturing.Copyright

Effects of feeding cracked corn to nursery and finishing pigs

Four experiments were conducted to determine the effects of supplementing cracked corn in nursery and finishing pig diets (PIC TR4 × 1050). In Exp. 1, 144 pigs (7.5 kg BW) were used in a 28-d experiment with 6 pigs per pen and 6 pens per treatment. Treatments were corn-soybean meal based in the form of mash, pellets (PCD), and pellets with 100% of the corn ground (PGr; 618 mm) or cracked (PCr; 3444 mm) and blended into the diet after the rest of the formulation had been pelleted. For d 0 to 28, pigs fed mash had increased (P = 0.042) ADFI compared with those fed the PCD diet. Pigs fed PCD had increased (P < 0.05) ADG and G:F compared with pigs fed PGr and PCr. Pigs fed PCr had decreased (P = 0.004) G:F compared with those fed PGr. For Exp. 2, 224 nursery pigs (7.4 kg BW) were used in a 28-d study with 7 pigs per pen and 8 pens per treatment. Treatments were similar to Exp. 1, with 50% of the corn either ground (445 mm) or cracked (2142 mm). For d 0 to 28, pigs fed mash had greater (P < 0.05) ADFI and G:F than pigs fed the PCD diet. Pigs fed the PCD diet had decreased (P = 0.001) ADFI and increased (P = 0.001) G:F compared to those fed PGr and PCr. For Exp. 3, 208 pigs (62.6 kg BW) were used in a 63-d experiment with 13 pigs per pen and 4 pens per treatment. Treatments were corn-soybean meal based with 0, 10, 20, and 40% cracked corn (3549 µm). All treatments were fed in mash form. For d 0 to 63, increasing cracked corn tended to decrease (linear, P = 0.093) G:F and decreased (linear, P = 0.047) carcass yield. Adding up to 40% of cracked corn to a mash diet decreased (P < 0.05) scores for keratinization and ulcers. For Exp. 4, 252 finishing pigs (40 kg BW) were used with 7 pigs per pen and 9 pens per treatment. The treatments were the same as described in Exp. 2. For the 80-d experiment, pigs fed mash had decreased (P < 0.05) ADG, stomach keratinization, and ulcer scores and increased (P < 0.05) yield and loin depth compared with pigs fed the PCD diet. Pigs fed PCD had increased (P < 0.05) ADG and G:F and decreased (P = 0.026) loin depth compared with pigs fed PGr and PCr diets. Pigs fed PCr had increased (P = 0.023) ADG and decreased (P = 0.001) yield compared with pigs fed PGr. Pigs fed PCr had decreased (P < 0.05) stomach keratinization and ulcer scores compared with pigs fed the PCD and PGr diets. In conclusion, pigs fed PCD had the greatest G:F, and PGr and PCr treatments had negative effects on G:F of pigs. Scores for stomach lesions were lowest for pigs fed PCr.

Impact of pelleting and acid pretreatment on biomass structure and thermal properties of wheat straw, corn stover, big bluestem, and sorghum stalk.

Agricultural residues and energy crops are considered potential feedstocks for bioethanol production because of their high availability and energy potential as well as relatively low cost. Previous studies have shown that pelleting biomass feedstocks could increase their bulk density, thus increasing ease of handling and decreasing cost of handling and transportation. The pelleting process has also been shown to have a positive impact on the sugar yield of biomass. However, the effects of the pelleting process on biomass structure have not yet been studied. Therefore, the objective of this study was to investigate the impact of dilute acid pretreatment and the pelleting process on biomass structure of cellulosic materials, including crystallinity index (CrI,%) measured by the x-ray diffraction (XRD) method, structure of constituents and chemical changes determined by Fourier transform infrared spectroscopy (FTIR) and solid-state cross-polarization/magic angle spinning (CP/MAS) 13C NMR spectroscopy, morphological structure determined by scanning electron microscopy (SEM), and thermal properties determined by thermogravimetric analysis (TGA). Wheat straw, big bluestem, corn stover, and photoperiod-sensitive sorghum were used for this study. Pelleting did not have a significant effect on the pattern of FTIR spectra and solid-state 13C NMR spectra of biomass. XRD analysis showed that biomass crystallinity increased after dilute acid pretreatment and the pelleting process. Based on SEM analysis of biomass, dilute acid pretreatment and pelleting enhanced the removal of the softened surface region of biomass. TGA analysis showed that the decomposition temperature of pelleted biomass was slightly higher than that of corresponding unpelleted biomass, indicating that the pelleted biomass was more thermally stable than the unpelleted biomass.

Effects of sorghum particle size on milling characteristics, growth performance, and carcass characteristics in finishing pigs.

A total of 200 finishing pigs (PIC TR4 × 1050; average initial BW of 103.2 lb) were used in a 69-d growth assay to determine the effects of sorghum particle size on growth performance. Pigs were sorted by sex and ancestry and balanced by BW, with 5 pigs per pen and 10 pens per treatment. Treatments were a corn-soybean meal-based control with the corn milled to a target mean particle size of 600 μm, and sorghum diets milled to a target mean particle size of 800, 600, or 400 μm. Actual mean particle sizes were 555 μm for corn, and 724, 573, and 319 μm for sorghum, respectively. Feed and water were offered on an ad libitum basis until the pigs were slaughtered (average final BW of 271 lb) at a commercial abattoir. Reducing sorghum particle size improved (linear, P < 0.01) F/G, and we observed a tendency for decreased (P < 0.06) ADFI. Reducing sorghum particle size from 724 to 319 μm had no effects on HCW, backfat thickness, loin depth, or percentage fat-free lean index (FFLI), but tended to increase (P < 0.06) carcass yield. Pigs fed the sorghum-based diets had no difference in growth performance or carcass characteristics compared with those fed the control diet, except carcass yield, which was numerically greater (P < 0.07) for pigs fed the sorghum-based diets. When using a regression equation, we determined that sorghum must be ground to 513 μm to achieve a F/G equal to that of a corn-based diet, with corn ground to 550 μm. In conclusion, linear improvements in F/G and carcass yield were demonstrated with the reduction of sorghum particle size to 319 μm. In this experiment, sorghum should be ground 42 μm finer than corn to achieve a similar feeding value.

Effects of adding cracked corn to a pelleted supplement for nursery and finishing pigs

Three experiments were conducted to determine the effects of supplementing cracked corn into diets of nursery and finishing pigs. In Exp. 1, 144 pigs were used in a 28-d trial. Pigs (PIC TR4 × 1050; initially 16.5 lb) were weaned and allotted with 6 pigs per pen (3 barrows and 3 gilts) and 6 pens per treatment. All pigs were fed a common diet for 7 d postweaning and the experimental diets for the next 28 d. Treatments were corn-soybean meal-based in the form of mash, pellets, and pellets with 100% of the corn either ground (618 μm) or cracked (3,444 μm) and blended into the diet after the rest of the formulation (the supplement) had been pelleted. Overall (d 0 to 28), ADG and F/G improved when pigs were fed the mash control compared to the pelleted diets (P < 0.001); however, this response was caused by the poor performance of pigs fed the supplement treatments, with the pigs fed the complete pellets having improved (P < 0.01) ADG and F/G compared with pigs fed the pelleted supplement blended with ground and cracked corn. Finally, pigs fed the supplement blended with cracked corn had numerically lower (P < 0.11) ADG and poorer (P < 0.001) F/G compared to those fed the supplement blended with ground corn.