Vol. 10 Issue 3 Jul.-Sep. 2019

Saowanee Srisomboon, Vut Tongnan, Navadol Laosiripojana, Unalome Wetwatana Hartley

Abstract: Perovskite -based La0.3Sr0.7Co0.7Fe0.3O3-δ (LSCF3773, LSCF) were used as a catalyst in synthesis gas production via an integration of nitrous oxide decomposition with methane partial oxidation reaction in a packed-bed reactor. LSCF powder was prepared by ethylene glycol modified Sol-gel-Pechini and sintered at 1100°C with slow heating rate in order to complete a pervoskite phase. A crystalline phase and a crystallite size of the synthesized powder were analyzed by x-ray diffraction technique (XRD). Partial oxidation was performed by feeding of CH4 and N2O in a packed-bed reactor. CH4-TPR was applied to investigate the CH4 absorption behavior on surface and in lattice of catalyst. The result of CH4-TPR  showed that CH4 consumption occurred during 900°C to 950°C in temperature, and at 920°C was found the highest of CH4 was oxidized with O2 on the surface and in the lattice and gave the highest products (H2 and CO), called methane partial oxidation reaction (POM). In reaction performance, suitable CH4/N2O molar ratio and operating temperature for the highest CH4 conversion at 99.31% and hydrogen (H2) to carbon monoxide (CO) ratio at 2.07 were achieved when introducing 1.08 molar ratio of CH4 to N2O at 950°C. The stability test of LSCF3773 performed 10 hours with a stable activity of catalyst by achieved 99% CH4 conversion throughout 10 hours and H2/CO ratio approached to 2 in POM reaction. LSCF3773 was considered as the phase reversibility by XRD after the stability test. The XRD pattern confirmed that the perovskite phase can appear again by full replenishing with O2 into the lattice, called as the regeneration with O2 treatment. As a result, LSCF3773 structure can appear again with the perovskite phase and can be renewable as a new catalyst in order to reuse in a new reaction. Therefore, in this work, La0.3Sr0.7Co0.7Fe0.3O3-δ can meet the objectives in terms of 1.) High CH4 conversion, 2.) Product selectivity with 2 of H2/CO ratio, which is dominant with partial oxidation reaction, and 3.) an ability for continuous running for 10 hours for co-feed N2O and CH4 at operating condition as 1.08 molar ratio of  CH4/N2O at 950°C. 4.) Regenerable property. 

Keywords: Perovskite-type material, Synthesis gas production, N2O decomposition, Partial oxidation of methane. 

Nattaya Huailuek, Thapat Silalertruksa and Shabbir H. Gheewala*

Abstract: Palm oil production has been growing over the past decade to fulfill the increased demands for vegetable oil and biodiesel. Along with crude palm oil production, a substantial amount of palm biomass is produced, inappropriate management of which would affect environmental performance, and consequently business competitiveness. Life cycle assessment (LCA) has been conducted to assess the environmental impacts of five different palm biorefinery scenarios for empty fruit bunch (EFB) management comparing them with the baseline scenario (i.e. mulching in oil palm plantations). The scenarios include (1) EFB and Palm Oil Mill Effluent (POME) co-compost and cogeneration, (2) EFB based ethanol production and cogeneration, (3) EFB briquette production and cogeneration, (4) EFB compost and cogeneration and (5) EFB cogeneration. The ReCiPe impact assessment methodology was used considering seven impacts categories, viz., global warming, acidification, freshwater eutrophication, marine eutrophication, photochemical oxidant formation, particular matter formation, and fossil depletion. The results revealed that the EFB and POME cocompost and cogeneration (Scenario 1), EFB compost and cogeneration (Scenario 4), and EFB cogeneration (Scenario 5) could help improve the environmental performance of the existing Thai palm oil industry. In terms of economic aspect, the cost-benefit analysis and net present value (NPV) were used to evaluate each scenario’s investment. The EFB and POME co-compost production (Scenario 1), EFB briquette production (Scenario 3), EFB compost (Scenario 4) and EFB cogeneration (Scenario 5) were financially feasible. However, the Scenario 1 was recommended due to the least investment and operation costs and the highest NPV. The EFB based ethanol production (Scenario 2) was not financially feasible. 

Keywords: Life Cycle Assessment, palm oil mill, biomass, biorefinery.

Sitthipong Pengjan, Chengliang Fan, Sébastien Bonnet and Savitri Garivait*

Abstract: Airborne particles are recognized for their adverse effects on human health and atmospheric visibility reduction, with more severe impacts in case of fine particles. Recent studies have revealed that the PM2.5/PM10 ratio can be used to estimate PM2.5 concentrations in the absence of direct measurements. This study investigated PM2.5/PM10 ratios and relationships with meteorological parameters and others gases, including temporal trends in the Bangkok Metropolitan Region (BMR). The results showed that the overall PM2.5/PM10 ratio during 2011-2017 was 0.64, pointing out that the BMR air quality is significantly affected by combustion related emission sources, in particular from on-road transport. Also, a difference in seasonality was observed since it was found that the overall ratio during 2011-2017 was 0.67 for the dry season, and 0.60 for the wet season. The PM2.5 to PM10 ratio values were found to be the highest at roadside stations followed by ambient and ambient-roadside stations. The PM2.5 to PM10 ratios exhibited an upward temporal trend. The ratios showed a positive association with rain and O3, and a negative association with wind speed and temperature. Wind speed in BMR is low and stable and it was observed that the PM2.5/PM10 ratio varied with location with a significant influence from local emission sources. A maximum PM2.5/PM10 ratio was reached during the dry season because of stable of wind speed, low temperature, low scavenging rate from rain and high concentration of O3 in the BMR. These results should contribute providing PM2.5 management and mitigations options in the BMR.

Keywords: PM2.5, PM2.5/PM10 ratio, Analysis, Bangkok Metropolitan Region, Thailand. 

May Yadanar Oo, Sébastien Bonnet* and Savitri Garivait

Abstract: Haze pollution from vegetation fires in the ASEAN region is a recurrent issue. Due to this problem, in 2002, ASEAN countries gathered efforts to tackle vegetation fires and reduce haze pollution in the region. In the case of Myanmar, vegetation fires remain to be assessed. This study aimed at investigating the spatio-temporal distribution of vegetation fires in Myanmar based on active fire data from MODIS. The results showed that 811,143 fire hotspots (FHS) were detected by MODIS over the period 2006-2017 with on average 68,000 FHS each year. Most of the FHS were found to occur on forest land, followed by other wooded land and crop land. Based on the distribution of FHS in Myanmar, a number of States and Regions were selected as priority areas for vegetation fires control to identify the main drivers. Through expert judgement by representatives from government organisations, it was found that the main drivers of vegetation fires in Myanmar include, in decreasing order of importance, burning for land clearance; burning for collection of wood and non-wood forest products; careless and accidental fires; burning for hunting; and burning for the removal of agricultural residues. 

Keywords: Fire Hotspots, MODIS Data, Land Cover Type, Vegetation Fires drivers, Myanmar.