Effect of Microwave Heating Variables on Nitrogen-Enriched Palm Shell Activated Carbon toward Efficient Hydrogen Sulfide Removal

2018 ◽  
Vol 280 ◽  
pp. 315-322
Author(s):  
N. Mohammad Nor ◽  
L. L. Chung ◽  
Bassim H. Hameed ◽  
S. Sethupathi ◽  
A. R. Mohamed

This research work is focuses on understanding the characteristics of modified nitrogen-enriched palm shell activated carbon (N-PSAC) that undergo different microwave (MW) operating parameters towards efficient H2S removal. The nitrogen functional groups were tailored onto PSAC micropore structures through impregnation of urea onto palm shell activated carbon (PSAC). The effect of MW heating variables (heating temperature, N2 flow rate, heating time and amount of adsorbent) on N-PSAC adsorbent was investigated and analyzed with respect to H2S adsorption capacity.One factor at a time (OFAT) approach was used to produce an efficient N-PSAC adsorbent, where theH2S breakthrough capacity (measured at 5% of H2S outlet concentration) attained was in the range of 98.71 – 211.35 mg/g.It was found that MW heating variables contribute a significant impactto the modification of N-PSAC adsorbent in catering the H2S emission.

2012 ◽  
Vol 610-613 ◽  
pp. 2000-2005
Author(s):  
Chun Yan Xu ◽  
Hong Jun Han

The uncertainty of operating parameters hinders the practical application of the biological desulfurization. To solve this problem, this study which was conducted in room temperature, pH around seven conditions, investigated the effects of the operating parameters on the hydrogen sulfide (H2S) removal performance in the biotrickling filter, including inlet H2S concentration, inlet flow rate or gas retention time, inlet volume load and circulating liquid spraying flux. The results showed that, the inlet H2S concentration should be controlled within 800mg/m3, 650mg/m3, 400mg/m3, 300mg/m3 respectively while the inlet flow rate was 150L/h, 200L/h, 250L/h, 300L/h, at those conditions, the outlet H2S concentrations were lower than 8mg/m3 and the H2S removal efficiencies were more than 98%. The optimum gas retention time was 12.37s, corresponding to the inlet flow rate of 200L/h, at this time, even if the inlet H2S concentration as high as 700mg/m3, the removal efficiency could be still more than 98%, the outlet concentration of H2S was only 13.1mg/m3. The maximum inlet volume load was 130g/(m3•h), in this condition, the outlet concentration of H2S could be controlled below 12mg/m3, the removal efficiency could above 98.4%.


2014 ◽  
Vol 9 (2) ◽  
pp. 179-191 ◽  
Author(s):  
S. Karimi ◽  
B. Ghobadian ◽  
G. Najafi ◽  
A. Nikian ◽  
R. Mamat

Abstract Bioethanol has been found to be a suitable substitute for gasoline in internal combustion engines. It could be used either in an undiluted form or blended with gasoline. To blend the ethanol and gasoline, the water content of ethanol should reach 0.5% or less. In the present research work, 3A Zeolite was used as an absorbent with vacuum distillation. The effects of the operating parameters such as temperature, vacuum pressure and vapor flow rate on ethanol–water separation were investigated. Final ethanol concentration was obtained at the end of every run as well as the concentration of outlet ethanol. Both linear regression and ANN design were used to determine the best fit for two final parameters. The optimum condition was obtained at 0.4 bar vacuum pressure and 20 l/min ethanol–water vapor flow rate. ANN model is more qualified to the simulation of outspread data while the linear regression is not. L10L10 mode and L5T10 mode provide the best results for final concentration and total time, respectively. The Trainlm Algorithm like the previous research training algorithm is the best.


2015 ◽  
Vol 34 (7) ◽  
pp. 667-674
Author(s):  
Jian Wu ◽  
Hongying Xia ◽  
Libo Zhang ◽  
Yi Xia ◽  
Jinhui Peng ◽  
...  

Abstract The present study reports the effect of microwave power and microwave heating time on activated carbon adsorption ability. The waste bamboo was used to preparing high surface area activated carbon via microwave heating. The bamboo was carbonized for 2 h at 600°C to be used as the raw material. According to the results, microwave power and microwave heating time had a significant impact on the activating effect. The optimal KOH/C ratio of 4 was identified when microwave power and microwave heating time were 700 W and 15 min, respectively. Under the optimal conditions, surface area was estimated to be 3441 m2/g with pore volume of 2.093 ml/g and the significant proportion of activated carbon was microporous (62.3%). The results of Fourier transform infrared spectroscopy (FTIR) were illustrated that activated carbon surface had abundant functional groups. Additionally the pore structure is characterized using Scanning Electron Microscope (SEM).


2014 ◽  
Vol 33 (5) ◽  
pp. 427-437
Author(s):  
Zhao-qiang Zheng ◽  
Hong-ying Xia ◽  
C. Srinivasakannan ◽  
Jin-hui Peng ◽  
Li-bo Zhang

AbstractEupatorium adenophorum was utilized as raw materials for the preparation of activated carbon via microwave assisted steam activation. Influences of the three vital process parameters – activation temperature, activation duration and steam flow rate – have been assessed on the adsorption capacity and yield of Eupatorium adenophorum activated carbon (EAAC). The process parameters were optimized utilizing the Design Expert software and were identified to be an activation duration of 45 min, an activation temperature of 950 °C and a steam flow rate of 0.7 ml/min, with the resultant iodine number and yield being 1,010 mg/g and 20.13% respectively. The validity of process model to optimize the process parameters was verified using the analysis of variance (ANOVA). The key parameters that characterize quality of the porous carbon such as the BET surface area, total pore volume and average pore diameter were estimated to be 1,142 m2/g, 0.84 ml/g and 3.3 nm respectively, for the sample corresponding to the optimized process conditions. Additionally the pore structure is characterized using Scanning Electron Microscope (SEM). The present work strongly supports utilization of Eupatorium adenophorum as a potential precursor through microwave heating.


2019 ◽  
Vol 20 (2) ◽  
Author(s):  
Morgan Hull

Hydrogen sulfide (H₂S) emissions from landfills negatively impact surrounding communities. In addition to an unpleasant, rotten-egg odor, inhalation of the gas can cause respiratory distress and irritation. Peak emissions are released from C&D landfills through the decomposition of gypsum drywall. Current removal technologies are costly and often ineffective. The goal of this research was to develop a cost-effective mat geared toward H₂S removal. Preliminary research revealed an increase in adsorption capacity through the addition of iron salts, FeCl3 and FeSO4, to activated carbon at a 5:1 carbon to iron ratio. To evaluate the effect of heat treatments on iron oxide formation, and subsequent adsorption capacity, samples were divided into heat treatment groups of 250ºC, 450ºC, and 650ºC. Samples were flushed with 100 ppm of H₂S under N₂ at 250 ml/min for two hours. Over this time duration, samples subjected to higher temperature heat treatments showed increased adsorption capacity. All heat treated samples demonstrated higher adsorption compared to the baseline non-heat treated samples. Additional research will be conducted to assess the effect of heat treatments above 650ºC.


2014 ◽  
Vol 695 ◽  
pp. 12-15 ◽  
Author(s):  
A.M. Abioye ◽  
Farid Nasir Ani

Biochar was produced from oil palm shell via microwave-induced pyrolysis. The biochar was subsequently activated via microwave assisted CO2 activation. A simple single layer arrangement of the microwave absorber (coconut shell based activated carbon) and oil palm shell in the reactor was adopted during pyrolysis. In recent times, the treatment of oil palm biomass using microwave heating technology has been on the increase. Value added products such as bio-oil, gas, biochar and activated carbon are being produced while at the same time serving as waste management control. Biochar is seen as a promising climate mitigation tool. Activated carbons can be used as absorbent for the removal of pollutants from wastewaters, as air pollution control and as electrode for supercapacitor. This paper presents comparative study between the characteristics of oil palm shell biochar and oil palm shell activated carbon. BET surface area and Scanning Electron Microscopy (SEM) were analyzed to establish the characteristics of the biochar and activated carbon.


2017 ◽  
Vol 751 ◽  
pp. 449-454 ◽  
Author(s):  
Pathompong Janetaisong ◽  
Viset Lailuck ◽  
Somsak Supasitmongkol

Biogas derived from anaerobic digestion of biological wastes has been extensively used for heating purposes and/or electricity generation. Presence of hydrogen sulfide (H2S) in biogas affects engine performance adversely, thus reducing H2S content is a valuable part in practical application before utilizing biogas. Adsorptive separation is very appealing due to being an economical and effective method including the use of iron oxide based adsorbents. Pelletization of iron oxide adsorbents has never been reported among the adsorbents described to date. Therefore, H2S capture in two iron oxides (ferric oxide (Fe2O3) and magnetite (Fe3O4)) was experimentally investigated to determine technical feasibility of shaping pellets based on active iron oxide sorbent in removing H2S from a simulated gas stream (0.35 vol.% H2S balanced in N2). Many factors affecting the behavior of gas adsorption such as gas in-flow rate, adsorption temperature, binder loadings and textural characteristics were considered. The pellet strengths were also undertaken using a bulk crushing strength analyzer. The results indicated that higher temperature favors the diffusion of H2S molecules from the surface into the bulk of iron oxides. The H2S-sorption capacity of Fe3O4 sorbent was higher than that of Fe2O3 sorbent corresponding with the different pore volume and surface area in each adsorbent. With the same active Fe3O4, the extruded pellet produced with starch binder showed the excellent H2S uptake and crushing resistance. The higher gas in-flow rate had positive impact to contacting efficiency and mass transfer of solid and gas phase. The adsorbed H2S gas can be readily desorbed from the pellets with the desorption temperature below 60°C and the H2S-sorption capacity was consistent over repeated cycles. The pellets can be reused several times for consecutive adsorption/desorption cycles, without loss of performance in a large-scale reactor and therefore represent serious candidates for use in commercial absorbers.


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