Hydrodynamics and heat transfer of suspended surface in a supercritical cfb furnace

With the scaling-up of CFB boilers, more heating surfaces like suspended surfaces and/or mid-partition walls, are arranged in the furnace to ensure adequate heat absorption. The length of suspended surface reaches almost half height of the furnace in the Baima 600MW supercritical CFB boiler. Since the gas-solids hydrodynamics and heat transfer on those surfaces are different from that on waterwall, further researches are needed to investigate the characteristics of hydrodynamics and heat transfer on the suspended surfaces. Beside the experimental measurements on the suspended surfaces in a scale down test rig, the hydrodynamic characteristics on the suspended surfaces were computed by a CFD simulation combined with EMMS model in a supercritical CFB of annular furnace. The results present an uneven axial solid concentration profile on the suspended surface, and descending particles are found on some locations especially where those surfaces far away from the furnace exits. Based on the gas-solids hydrodynamic results, the modified cluster renewal model was applied in the heat transfer coefficient calculation of the suspended surfaces. The result shows the heat transfer coefficient varies with the height and it has difference between two sides of a surface. In addition, the average heat transfer coefficients of suspended surface at different locations are compared. References Basu P, Nag P K. Heat transfer to walls of a circulating fluidized-bed furnace[J]. Chemical Engineering Science, 1996, 51(1): 1-26. Cen K F, Ni M J, Luo Z Y, et al. Theoretical design and operation of circulating fluidized bed boiler[J]. China Electric Power Press, Beijing, 1998: 647-663. Cheng L M, Wang Q H, Shi Z L, et al. Heat transfer in a large circulating fluidized bed boiler[J]. Journal of Power Engineering, 2006, 26(3): 305-310. Huang C, Cheng L M, Zhou X L, et al. Suspended surface heat transfer in a large circulating fluidized bed boiler furnace[J]. Journal of Zhejiang University. Engineering Science, 2012, 46(11): 2128-2132. Sundaresan R, Kolar A K. Axial heat transfer correlations in a circulating fluidized bed riser[J]. Applied Thermal Engineering, 2012. * “Strategic Priority Research Program” of the Chinese Academy of Sciences, Grant No. XDA0703010

Research on coal staged conversion poly-generation system based on fluidized bed

Abstract A new coal staged conversion poly-generation system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal. Coal is the first pyrolysed in a fluidized pyrolyzer. The pyrolysis gas is then purified and used for chemical product or liquid fuel production. Tar is collected during purification and can be processed to extract high value product and to make liquid fuels by hydro-refining. Semi-coke from the pyrolysis reactor is burned in a circulating fluidized bed (CFB) combustor for heat or power generation. The system can realize coal multi-product generation and has a great potential to increase coal utilization value. A 1 MW poly-generation system pilot plant and a 12 MW CFB gas, tar, heat and power poly-generation system was erected. The experimental study focused on the two fluidized bed operation and characterization of gas, tar and char yields and compositions. The results showed that the system could operate stable, and produce about 0.12 m3/kg gas with 22 MJ/m3 heating value and about 10 wt% tar when using Huainan bituminous coal under pyrolysis temperature between 500 and 600 °C. The produced gases were mainly H2, CH4, CO, CO2, C2H4, C2H6, C3H6 and C3H8. The CFB combustor can burn semi-coke steadily. The application prospect of the new system was discussed

Downregulation of AC092894.1 promotes oxaliplatin resistance in colorectal cancer via the USP3/AR/RASGRP3 axis

Abstract Background Oxaliplatin resistance is a complex process and has been one of the most disadvantageous factors and indeed a confrontation in the procedure of colorectal cancer. Recently, long non-coding RNAs (lncRNAs) have emerged as novel molecules for the treatment of chemoresistance, but the specific molecular mechanisms mediated by them are poorly understood. Methods The lncRNAs associated with oxaliplatin resistance were screened by microarray. lncRNA effects on oxaliplatin chemoresistance were then verified by gain- and loss-of-function experiments. Finally, the potential mechanism of AC092894.1 was explored by RNA pull-down, RIP, and Co-IP experiments. Results AC092894.1 representation has been demonstrated to be drastically downregulated throughout oxaliplatin-induced drug-resistant CRC cells. In vivo and in vitro experiments revealed that AC092894.1 functions to reverse chemoresistance. Studies on the mechanism suggested that AC092894.1 served as a scaffold molecule that mediated the de-ubiquitination of AR through USP3, thereby increasing the transcription of RASGRP3. Finally, sustained activation of the MAPK signaling pathway induced apoptosis in CRC cells. Conclusions In conclusion, this study identified AC092894.1 as a suppressor of CRC chemoresistance and revealed the idea that targeting the AC092894.1/USP3/AR/RASGRP3 signaling axis is a novel option for the treatment of oxaliplatin resistance