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Volatile Organic Compounds (VOCs) are widely measured at ppb and ppt level in many contexts, from therapeutic drug control in respiratory diseases to monitoring of climate change and indoor air quality. The need for accuracy is a common denominator in all these fields. The interactions between gas mixtures and solid surfaces in sampling lines and instruments play an important role in calculating the total uncertainty of the amount of VOC. The amount of substances in the gas mixture is affected by its reversible and irreversible interactions with the sampling line. The main aim of this paper is to propose and discuss a method to quantify the amount of substance segregated by reversible interactions on sampling lines. To validate the proposed method, the areic amount of a VOC (Acetone) is measured for a commercial test pipe (Sulfinert®) as the amount of substance per unit area of the internal surface of the test pipe segregated from the flowing gas mixture. Stainless steel coated by Sulfinert® was chosen as a test material because of its wide use and its limited irreversible and permeation effects. A certified gas mixture of Acetone in air with a nominal mole fraction of 10 µmol mol−1 was used for validation. Broad temperature control was used and the sensibility of the method to the temperature and the pressure has been evaluated to correct the bias due to physical condition. The sensitivity to the residence time and the Reynolds number of the gas flow has been evaluated to verify the reaching of equilibrium and the limits of the applicability of the method. The areic amount of Acetone at equilibrium on Sulfinert® coated pipe was measured as 40 nmol m−2, and an equilibrium constant value of around 0.2 m was calculated as the ratio between the superficial amount segregated on the wall and the amount concentration of Acetone in the mixture, both at the equilibrium. The observed reproducibility was better than 2.5%. This method is aimed to investigate VOC losses due to interactions for many VOC/material systems at a lower amount of substance levels.
Guido Sassi; Bilal Khan; Maricarmen Lecuna. Reproducibility of the Quantification of Reversible Wall Interactions in VOC Sampling Lines. Atmosphere 2021, 12, 280 .
AMA StyleGuido Sassi, Bilal Khan, Maricarmen Lecuna. Reproducibility of the Quantification of Reversible Wall Interactions in VOC Sampling Lines. Atmosphere. 2021; 12 (2):280.
Chicago/Turabian StyleGuido Sassi; Bilal Khan; Maricarmen Lecuna. 2021. "Reproducibility of the Quantification of Reversible Wall Interactions in VOC Sampling Lines." Atmosphere 12, no. 2: 280.
The study experimentally investigated a novel approach for producing hydrogen from methane cracking in dielectric barrier discharge catalytic plasma reactor using a nanocatalyst. Plasma-catalytic methane (CH4) cracking was undertaken in a dielectric barrier discharge (DBD) catalytic plasma reactor using Ni/MgAl2O4. The Ni/MgAl2O4 was synthesised through co-precipitation followed customised hydrothermal method. The physicochemical properties of the catalyst were examined using X-ray diffraction (XRD), scanning electron microscopy—energy dispersive X-ray spectrometry (SEM-EDX) and thermogravimetric analysis (TGA). The Ni/MgAl2O4 shows a porous structure spinel MgAl2O4 and thermal stability. In the catalytic-plasma methane cracking, the Ni/MgAl2O4 shows 80% of the maximum conversion of CH4 with H2 selectivity 75%. Furthermore, the stability of the catalyst was encouraging 16 h with CH4 conversion above 75%, and the selectivity of H2 was above 70%. This is attributed to the synergistic effect of the catalyst and plasma. The plasma-catalytic CH4 cracking is a promising technology for the simultaneous H2 and carbon nanotubes (CNTs) production for energy storage applications.
Asif Hussain Khoja; Abul Kalam Azad; Faisal Saleem; Bilal Alam Khan; Salman Raza Naqvi; Muhammad Taqi Mehran; Nor Aishah Saidina Amin. Hydrogen Production from Methane Cracking in Dielectric Barrier Discharge Catalytic Plasma Reactor Using a Nanocatalyst. Energies 2020, 13, 5921 .
AMA StyleAsif Hussain Khoja, Abul Kalam Azad, Faisal Saleem, Bilal Alam Khan, Salman Raza Naqvi, Muhammad Taqi Mehran, Nor Aishah Saidina Amin. Hydrogen Production from Methane Cracking in Dielectric Barrier Discharge Catalytic Plasma Reactor Using a Nanocatalyst. Energies. 2020; 13 (22):5921.
Chicago/Turabian StyleAsif Hussain Khoja; Abul Kalam Azad; Faisal Saleem; Bilal Alam Khan; Salman Raza Naqvi; Muhammad Taqi Mehran; Nor Aishah Saidina Amin. 2020. "Hydrogen Production from Methane Cracking in Dielectric Barrier Discharge Catalytic Plasma Reactor Using a Nanocatalyst." Energies 13, no. 22: 5921.
The severe consequences of carbon dioxide (CO2) emissions into the atmosphere and a dire need for freshwater are among the biggest global challenges. The desire to meet these challenges has given rise to the motivation of proposing a direct contact membrane distillation (DCMD) technology integrated with the CO2 capture unit to mitigate CO2 and simultaneously produce freshwater. The CO2 capture unit has been modeled with Aspen Plus® V.10 and for the DCMD system, MATLAB software was adopted. MATLAB software was not linked to the Aspen Plus®. Thermal heat contained in both the purged gas and leanout stream was recovered by using a DCMD unit. A blended solution of methyldiethanolamine (MDEA) and piperazine (PZ) was considered as an absorbent to remove CO2 from the flue gas of a large-scale coal-fired power plant (650 MWe). About 85 % of the CO2 in the flue gas has been captured from the top of the stripper column. At MDEA/PZ (concentration ratio of MDEA and PZ in the aqueous solution) concentration of 30/20 wt.%, a reboiler duty of 3.27 MJ/kg CO2 was obtained. Freshwater was produced at a rate of 25.43 m3/day from DCMD unit 1 and 1428.19 m3/day from unit 2.
Asad Ullah; Mujeeb Iqbal Soomro; Woo-Seung Kim; Bilal Alam Khan; Salman Memon; Saddam Hussain Soomro. Integration of CO2 capture unit with membrane distillation technology: CO2 mitigation and freshwater production. Chemical Engineering and Processing - Process Intensification 2020, 158, 108185 .
AMA StyleAsad Ullah, Mujeeb Iqbal Soomro, Woo-Seung Kim, Bilal Alam Khan, Salman Memon, Saddam Hussain Soomro. Integration of CO2 capture unit with membrane distillation technology: CO2 mitigation and freshwater production. Chemical Engineering and Processing - Process Intensification. 2020; 158 ():108185.
Chicago/Turabian StyleAsad Ullah; Mujeeb Iqbal Soomro; Woo-Seung Kim; Bilal Alam Khan; Salman Memon; Saddam Hussain Soomro. 2020. "Integration of CO2 capture unit with membrane distillation technology: CO2 mitigation and freshwater production." Chemical Engineering and Processing - Process Intensification 158, no. : 108185.
A piperazine (PZ)-promoted methyldiethanolamine (MDEA) solution for a carbon dioxide (CO2) removal process from the flue gas of a large-scale coal power plant has been simulated. An Aspen Plus® was used to perform the simulation process. Initially, the effects of MDEA/PZ concentration ratio and stripper pressure on the regeneration energy of CO2 capture process were investigated. The MDEA/PZ concentration ratio of 35/15 wt.% (35 wt. MDEA and 15 wt.% PZ) was selected as an appropriate concentration. The reboiler duty of 3.235 MJ/kg CO2 was obtained at 35/15 wt.% concentration ratio of MDEA/PZ. It was considered a reference or base case, and process modifications including rich vapor compression (RVC) process, cold solvent split (CSS), and the combination of both processes were investigated to check its effect on the energy requirement. A total equivalent work of 0.7 MJe/kg CO2 in the RVC and a reboiler duty of 2.78 MJ/kg CO2 was achieved in the CSS process. Similarly, the total equivalent work, reboiler duty, and condenser duty of 0.627 MJe/kg CO2, 2.44 MJ/kg CO2, and 0.33 MJ/kg CO2, respectively, were obtained in the combined process. The reboiler duty and the total equivalent work were reduced by about 24.6 and 16.2%, respectively, as compared to the reference case. The total energy cost saving was 1.79 M$/yr. Considering the additional equipment cost in the combined process, the total cost saving was 0.67 M$ per year.
Bilal Alam Khan; Asad Ullah; Muhammad Wajid Saleem; Abdullah Nawaz Khan; Muhammad Faiq; Mir Haris. Energy Minimization in Piperazine Promoted MDEA-Based CO2 Capture Process. Sustainability 2020, 12, 8524 .
AMA StyleBilal Alam Khan, Asad Ullah, Muhammad Wajid Saleem, Abdullah Nawaz Khan, Muhammad Faiq, Mir Haris. Energy Minimization in Piperazine Promoted MDEA-Based CO2 Capture Process. Sustainability. 2020; 12 (20):8524.
Chicago/Turabian StyleBilal Alam Khan; Asad Ullah; Muhammad Wajid Saleem; Abdullah Nawaz Khan; Muhammad Faiq; Mir Haris. 2020. "Energy Minimization in Piperazine Promoted MDEA-Based CO2 Capture Process." Sustainability 12, no. 20: 8524.