scholarly journals Transient Flow Rate Ramps for Methanation of Carbon Dioxide in an Adiabatic Fixed‐Bed Recycle Reactor

2019 ◽  
Vol 8 (3) ◽  
pp. 1901116 ◽  
Author(s):  
Steffi Theurich ◽  
Stefan Rönsch ◽  
Robert Güttel
2018 ◽  
Vol 57 (18) ◽  
pp. 6391-6400 ◽  
Author(s):  
Steffi Matthischke ◽  
Stefan Roensch ◽  
Robert Güttel

Author(s):  
Yanbing Li ◽  
Rui Xiao ◽  
Baosheng Jin ◽  
Huiyan Zhang

As one of the fundamental issues of the new poly-generation system on the basis of gasification gas and coke oven gas, carbon dioxide reforming of methane experiments have been performed over coal chars derived from different parent coals in a lab-scale fixed-bed reactor (internal diameter 12 mm, length 700 mm). The char derived from TongChuan coal exhibited higher activity than other samples employed under the same conditions. After the reforming reaction, the char samples were covered with different amounts of carbon deposition which resulted in the surface areas decrease. As the flow rate of feed gas increased from 200 ml/min to 600 ml/min over the Xuzhou char sample at 1050 degrees Celsius, the conversion of methane decreased from 52.7% to 17.5% and the H2 /CO dropped from 0.75 to 0.55. While maintaining the flow rate of CO2 at 20ml/min at 1050 degrees Celsius, the mole ratio of reactants CH4/CO2 was varied from 1 to 1.75 which led to the H2/CO ratio increase from 0.75 to 1.2.


Author(s):  
Jinlan Gou ◽  
Wei Wang ◽  
Can Ma ◽  
Yong Li ◽  
Yuansheng Lin ◽  
...  

Using supercritical carbon dioxide (SCO2) as the working fluid of a closed Brayton cycle gas turbine is widely recognized nowadays, because of its compact layout and high efficiency for modest turbine inlet temperature. It is an attractive option for geothermal, nuclear and solar energy conversion. Compressor is one of the key components for the supercritical carbon dioxide Brayton cycle. With established or developing small power supercritical carbon dioxide test loop, centrifugal compressor with small mass flow rate is mainly investigated and manufactured in the literature; however, nuclear energy conversion contains more power, and axial compressor is preferred to provide SCO2 compression with larger mass flow rate which is less studied in the literature. The performance of the axial supercritical carbon dioxide compressor is investigated in the current work. An axial supercritical carbon dioxide compressor with mass flow rate of 1000kg/s is designed. The thermodynamic region of the carbon dioxide is slightly above the vapor-liquid critical point with inlet total temperature 310K and total pressure 9MPa. Numerical simulation is then conducted to assess this axial compressor with look-up table adopted to handle the nonlinear variation property of supercritical carbon dioxide near the critical point. The results show that the performance of the design point of the designed axial compressor matches the primary target. Small corner separation occurs near the hub, and the flow motion of the tip leakage fluid is similar with the well-studied air compressor. Violent property variation near the critical point creates troubles for convergence near the stall condition, and the stall mechanism predictions are more difficult for the axial supercritical carbon dioxide compressor.


2004 ◽  
Vol 30 (6) ◽  
pp. 758-761
Author(s):  
Tomio MIMURA ◽  
Yasuyuki YAGI ◽  
Masaki IIJIMA ◽  
Ryuji YOSIYAMA ◽  
Takahito YONEKAWA

2014 ◽  
Vol 16 (2) ◽  
pp. 76-81 ◽  
Author(s):  
Anny Sulaswatty ◽  
Egi Agustian

Potensi Indonesia akan minyak akar wangi yang berorientasi ekspor dalam industri kosmetik, parfum, sabun, keperluan terapi, antiseptik, massage oil, farmasi dan pestisida memberikan peluang yang besar untuk memenuhi kebutuhan dunia. Guna nilai tambah minyak akar wangi dengan meningkatkan kadar vetiverol sebagai komponen utama, diaplikasikan teknologi ekstraksi fluida karbondioksida superkritik yang merupakan perpaduan ekstraksi, fraksinasi dan deodorisasi dengan didukung keunggulan karbondioksida sebagai pelarut yang inert, ramah lingkungan, mudah dipisahkan, dan berdaya larut tinggi.  Minyak akar wangi Garut (Java vetiver oil) sebagai bahan baku, mempunyai karakteristik  kadar vetiverol  39.03 %; Bobot jenis 0.9977; indeks bias 1.5247;  putaran optik +38.1; kelarutan dalam alkohol 95%  yaitu 1:1 jernih; bilangan asam 28.1; bilangan ester 24.6; bilangan ester setelah asetilasi 115.5; serta tidak mengandung minyak lemak dan  minyak keruing. Pemilihan kondisi proses guna menghasilkan kandungan vetiverol optimal dilakukan dengan memvariasikan laju alir gas CO2, tekanan dan suhu sebagai parameter penting dalam keberhasilan proses ekstraksi minyak akar wangi dengan fluida CO2 superkritik. Pemilihan laju alir konstan dan lebih stabil  diperoleh pada 5.5 liter/menit, sedangkan untuk variasi tekanan ekstraktor (1500, 1750, 2000 psi) dan suhu ekstraktor (40-50oC);  tekanan dan suhu separator  500 psi dan 25oC serta waktu proses selama lima jam dengan pengambilan ekstrak setiap jam. Tekanan dan suhu proses yang optimal diperoleh pada 1750 psi dan suhu 40oC  dengan  rafinat minyak akar wangi berkadar vetiverol  51.82 %,  bilangan ester 7.2 dan bilangan ester setelah asetilasi  172.4. Tingginya tekanan dan rendahnya suhu berpengaruh terhadap perolehan ekstrak; penurunan rafinat; peningkatan nilai  bobot jenis ekstrak dan rafinat; indeks bias ekstrak dan rafinat; putaran optik ekstrak dan rafinat; peningkatan viskositas ekstrak dan rafinat; peningkatan bilangan ester ekstrak, bilangan ester setelah asetilasi ekstrak, serta kandungan vetiverol.Kata Kunci: Minyak Akar Wangi, Vetiverol, Ekstraksi Fluida Superkritik Potential Indonesian vetiver oil export oriented industry of cosmetics, perfumes, soaps, therapeutic purposes, antiseptic, massage oil, pharmaceutical and pesticide presents a great opportunity to meet the needs of the world. In order to add value vetiver oil by increasing the levels vetiverol as the main component, was applied to carbon dioxide supercritical fluid extraction technology which is a combination of extraction, fractionation and deodorization with excellence supported carbon dioxide as an inert solvent, eco-friendly, easily separated, and the high solubility. Garut vetiver oil (Java vetiver oil) as raw material, has the characteristics vetiverol levels 39.03%, specific gravity of 0.9977; refractive index of 1.5247; optical rotation +38.1; solubility in alcohol 95% is a clear 1:1; acid number 28.1; ester number 24.6; ester number after acetylation 115.5; as well as fats and oils contain no oil keruing. The selection process conditions in order to produce optimal vetiverol content performed by varying the flow rate of CO2 gas, pressure and temperature as an important parameter in the success of vetiver oil extraction with supercritical CO2 fluid. The selection of a constant flow rate and more stable obtained at 5.5 liters / min, whereas for pressure variation extractor (1500-2000 psi) and extractor temperature (40-50oC); separator pressure and temperature of 500 psi and 25 °C as well as the processing time for five hours by taking extracts every hour. Pressure and temperature optimum process obtained at 1750 psi and a temperature of 40oC with rafinat vetiverol vetiver oil yield of 51.82%, ester number 7.2, and ester number after acetylation 172.4. The high pressure and low temperature affect the acquisition of the extract; rafinat decline; increase in the value of specific gravity and rafinat extracts; refractive index and rafinat extract; optical rotation and rafinat extract; increase in the viscosity of the extract and rafinat; increase in numbers ester extract, ester number after acetylation extracts, as well as the content vetiverol. Key word: Vetiver Oil, Vetiverol, Supercritical Fluid Extraction.


2005 ◽  
Vol 48 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Ana Cristina Atti-Santos ◽  
Marcelo Rossato ◽  
Luciana Atti Serafini ◽  
Eduardo Cassel ◽  
Patrick Moyna

In this work lime essential oils were extracted by hydrodistillation and supercritical carbon dioxide. In the case of hydrodistillation, the parameters evaluated were extraction time and characteristics of the plant material. In supercritical extraction, the parameters evaluated were temperature, pressure, CO2 flow, extraction time and material characteristics. Considering citral content, the best results for hydrodistillation were obtained with a distillation time of 3 hours using whole peels. The best results for supercritical extraction were found using 60ºC, 90 bar, at a CO2 flow rate of 1 mL/ min for 30 minutes using milled peels. The best yields of lime oil were obtained by hydrodistillation (5.45% w/w) and supercritical extraction (7.93% w/w) for milled peels.


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