Sugarcane is an important commercial crop cultivated for its stalks and sugar is a prized commodity essential in human nutrition. Proteomics of sugarcane is in its infancy, especially when dealing with the stalk tissues, where there is no study to date. A systematic proteome analysis of stalk tissue yet remains to be investigated in sugarcane, wherein the stalk tissue is well known for its rigidity, fibrous nature, and the presence of oxidative enzymes, phenolic compounds and extreme levels of carbohydrates, thus making the protein extraction complicated. Here, we evaluated five different protein extraction methods in sugarcane stalk tissues. These methods are as follows: direct extraction using lysis buffer (LB), TCA/acetone precipitation followed by solubilization in LB, LB containing thiourea (LBT), and LBT containing tris, and phenol extraction. Both quantitative and qualitative protein analyses were performed for each method. 2-DE analysis of extracted total proteins revealed distinct differences in protein patterns among the methods, which might be due to their physicochemical limitations. Based on the 2-D gel protein profiles, TCA/acetone precipitation-LBT and phenol extraction methods showed good results. The phenol method showed a shift in pI values of proteins on 2-D gel, which was mostly overcome by the use of 2-D cleanup kit after protein extraction. Among all the methods tested, 2-D cleanup-phenol method was found to be the most suitable for producing high number of good-quality spots and reproducibility. In total, 30 and 12 protein spots commonly present in LB, LBT and phenol methods, and LBT method were selected and subjected to eLD-IT-TOF-MS/MS and nESI-LC-MS/MS analyses, respectively, and a reference map has been established for sugarcane stalk tissue proteome. A total of 36 nonredundant proteins were identified. This is a very first basic study on sugarcane stalk proteome analysis and will promote the unexplored areas of sugarcane proteome research.

Methane, the final product of methanogenesis during anaerobic digestion is a low value product (0.1$/m3). Concerns over fugitive emissions from methane coupled with recent reduction in costs of solar and...

This paper reports a three-dimensional (3D) computational fluid dynamics (CFD) simulation of a laboratory scale fluid catalytic cracking unit (FCCU) stripper. Solid holdup and solid mixing were studied in a geometrically and dynamically scaled down cold model FCCU stripper fitted with disk and donut baffles. The solid holdup was measured using a γ-ray densitometry technique with a 3 μCi strength 137 Cs radioactive source. Measurements were taken at different axial levels, for different chordal positions. An Eulerian−Eulerian approach was used to simulate the gas−solid flow in the stripper column. The CFD simulations predicted asymmetric solid holdup profiles emphasizing the importance of 3D simulations. The CFD model predictions matched well with the solid holdup data from experiments. The CFD model also clearly predicted the recirculation and dead zones as noticed in the experimental analysis. Local defluidization zones were also noticed near the donut baffle wall regions. The particle axial velocity was low near the baffle walls, indicating that the particles slide down on the baffle walls. The radial and axial variations of solid holdup are discussed in this work, giving new knowledge in the complex countercurrent operation. This work is first of its kind to report detailed 3D study on the hydrodynamics of stripper operation both in cold flow and in the CFD model. ■ INTRODUCTIONFluid catalytic cracking (FCC) is the main heavy oil conversion process in most petroleum refineries. 1 In an FCC unit, the cracking reaction takes place in a riser. The catalyst is then separated from the product and is regenerated in a regenerator before recirculating into the riser again. The spent catalyst coming out of the riser contains valuable hydrocarbon product along with coke adsorbed on the surface. It is important to strip these hydrocarbons quickly and efficiently prior to the regeneration. Incomplete stripping not only leads to loss of valuable hydrocarbon to the regenerator, it also affects the heat balance by increasing the regenerator dense bed temperature which in turn can lead to faster deactivation. 2,3 The higher regenerator dense bed temperature also leads to lower unit conversions. All these issues make stripping an important operation in the FCC unit.The FCC stripper in the current study is an annular vessel that is designed to be concentric with and around the riser column. Steam is bubbled upward in a countercurrent manner to the catalyst particles flowing downward. Typically, FCC strippers have steam superficial velocity between 0.15 and 0.3 m/s and a catalyst mass flux of 30−75 kg/m 2 ·s. 4 Flooding, bridging, and large scale maldistribution are some of the common flow problems encountered in stripping operations. Flooding can be caused by high catalyst and high steam rates or by restrictive baffle designs. Flooding may result in carryover of injected steam to the regenerator by the catalyst particles due to its relative higher local velocity. 5 Bridging is caused due to nonuniform steam distribution inside ...

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