Adsorption dynamics of ethane from air in structured fixed beds with different microfibrous composites

Adsorption dynamics of ethane in two granular fixed beds and structured fixed beds with microfibrous composites was studied.5A zeolite membrane 5A/PSSF(paper-like sintered stainless steel fiber)and microfibrous entrapped activated carbon(MEAC)composites were prepared by wet layup papermaking/sintering technique and in-situ hydrothermal method.Microfibrous composites were characterized by X-ray diffraction,scanning electron microscopy and N2 adsorption/desorption.Structured fixed beds were designed by filling granular adsorbents(5A zeolite or activated carbon)and microfibrous composites at the inlet and outlet of the beds,respectively.Effects of flow rate,bed height and structure on the breakthrough curves were investigated.The length of unused bed(LUB)was determined,and Yoon–Nelson model was used to fit the breakthrough curves.The experimental results showed ethane was effectively adsorbed on the granular adsorbents and microfibrous composites.Both composites could decrease the LUB values and enhance bed utilization.All breakthrough curves fitted well to Yoon–Nelson model,with correlation coefficient exceeding 0.89.The adsorption rate of ethane could be improved in the structured fixed beds,which showed an enhanced mass transfer efficiency for ethane adsorption.LUB values of structured fixed beds with 5A/PSSF composites were larger,the bed utilization values were lower,and the adsorption rate constants were higher than those with MEAC composites under the same conditions.

A Study on Investment Structure of Fixed Assets and Regional Economic Growth

Nowadays,it has been in the period of rapidly developing China’s economy.Since the financial crisis in 2008,China has paid more and more attention to investing in fixed assets,and the growth rate of investing in fixed asset is also rising.However,when promoting regional economic growth,if we only pay attention to the total amount of fixed asset investment,there will inevitably exist some blindness and lack of sustainability.Therefore,the study between the investment structure of fixed assets and regional economic growth is quite important.China has a vast territory and many regions.The investment structure of fixed assets in different regions is also different,so the influence on economic growth is also different.This paper analyzes the investment structure of fixed assets and regional economic growth,and help realize the rapid growth of regional economy by recognizing the current situation of China's investment structure of fixed assets.

考虑拆解的老龄固定式离岸平台条件评估技术的历史回顾

In this study,the technical papers on structural condition assessment of aged fixed-type offshore platforms reported over the past few decades are presented.Other ancillary related works are also discussed.Large numbers of researches are available in the area of requalification for life extension of offshore jacket platforms.Many of these studies involve reassessment of existing platforms by means of conducting pushover analysis,a static nonlinear collapse analysis method to evaluate the structure nonlinear behaviour and capacity beyond the elastic limit.From here,the failure mechanism and inherent reserve strength/capacity of the overall truss structure are determined.This method of doing reassessment is described clearly in the industry-adopted codes and standards such the API,ISO,PTS and NORSOK codes.This may help understand the structural behaviour of aged fixed offshore jacket structures for maintenance or decommissioning.

Preparation and characterization of novel carbon molecular sieve membrane/PSSF composite by pyrolysis method for toluene adsorption

Carbon molecular sieve membrane(CMSM)/paper-like stainless steel fibers(PSSF)has been manufactured by pyrolyzing poly(fiirfuryl alcohol)(PFA)coated on the metal fibers.PFA was synthesized using oxalic acid dihydrate as a catalyst and coated on microfibers by dip coating method.For the purpose of investigating the effects of final carbonization temperature,the composites were carbonized between 400℃ and 800℃ under flowing nitrogen.The morphology and microstructure were examined by X-ray diffraction,Fourier transforms infrared spectroscopy,scanning electron microscopy,thermogravimetric analysis,N2 adsorption and desorption,Raman spectra and X-ray photoelectron spectra.The consequences of characterization showed that the CMSM containing mesopores o f 3.9 nm were manufactured.The specific surface area of the CMSM/PSSF fabricated in different pyrolysis temperature varies from 26.5 to 169.1 m^2·g^-1 and pore volume varies from 0.06 to 0.23 cm^3·g^-1.When pyrolysis temperature exceeds 600℃,the specific surface,pore diameter and pore volume decreased as carbonization temperature increased.Besides,the degree of graphitization in carbon matrix increased with rising pyrolysis temperature.Toluene adsorption experiments on different structured fixed bed that was padded by CMSM/PSSF and granular activated carbon(GAC)were conducted.For the sake of comparison,adsorption test was also performed on fixed bed packed with GAC.The experimental results indicated that the rate constant κ′ was dramatically increased as the proportion of CMCM/PSSF composites increased on the basis of Yoon-Nelson model,which suggested that structured fixed bed padded with CMSM/PSSF composite offered higher adsorption rate and mass transfer efficiency.