Conversion of palm oil sludge to biodiesel using alum and KOH as catalysts

Air pollution has become one of the key environmental concerns in the urban sustainable development. It is important to evaluate the impact of air pollution on socioeconomic development since it is the prerequisite to enforce an effective prevention policy of air pollution. In this paper, we model the impact of air pollution on the urban economic development as a Multiple Criteria Decision Making (MCDM) problem. In particular, we propose a novel Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) analysis framework to evaluate multiple factors of air pollutants and economic development. Our method can overcome the drawbacks of conventional TOPSIS methods by using Bayesian regularization and the Back-Propagation (BP) neural network to optimize the weight training process. We have conducted a case study to evaluate our proposed framework.

A Smart MCDM Framework to Evaluate the Impact of Air Pollution on City Sustainability: A Case Study from China

Abstract Conversion of palm oil sludge was studied by esterification and transesterification which used methanol as a reactant. The esterification of palm oil sludge was performed by variation of molar ratios of methanol to palm oil sludge (5:1, 10:1, 15:1, 20:1, and 25:1) and percentages of alum catalyst (3–7 wt%) at 60 °C for 3 h with stirring rate 300 rpm. Transesterification was also carried out by variation of KOH (0.5–2.5 wt%) at 60 °C and stirring rate 300 rpm for 1 h. The optimum molar ratio of methanol to palm oil sludge was 20:1 (6% alum catalyst). Meanwhile, the optimum concentration for transesterification was 1.5% of KOH. The yield of biodiesel production was 93%, the density and kinematic viscosity were 0.864 g mL−1 and 12.8 mm2 s−1, respectively. The existence of ester compounds in the product was shown by Fourier Transform Infrared Spectrometry spectrum data of carbonyl group (C O) at 1744 cm−1 and C O of ester at 1234; 1119 and 1026 cm−1. Gas Chromatograph-Mass Spectrometry analysis showed the biodiesel product contains palmitic acid methyl ester (23.4%), trans-methyl oleate (75.5%), cis-methyl oleate (

Plagiat checker: Conversion of palm oil sludge to biodiesel using alum and KOH as catalysts

The nocturnal boundary layer transition from weakly to very stable. Part II: Numerical simulation with a second-order model

The collapse of turbulence in the nocturnal boundary layer is studied by means of a simple bulk model that describes the basic physical interactions in the surface energy balance. It is shown that for a given mechanical forcing, the amount of turbulent heat that can be transported downward is limited to a certain maximum. In the case of weak winds and clear skies, this maximum can be significantly smaller than the net radiative loss minus soil heat transport. In the case when the surface has low heat capacity, this imbalance generates rapid surface cooling that further suppresses the turbulent heat transport, so that eventually turbulence largely ceases (positive feedback mechanism). The model predicts the minimum wind speed for sustainable turbulence for the so-called crossing level. At this level, some decameters above the surface, the wind is relatively stationary compared to lower and higher levels. The critical speed is predicted in the range of about 5–7 m s21, depending on radiative forcing and surface properties, and is in agreement with observations at Cabauw. The critical value appears not very sensitive to model details or to the exact values of the input parameters. Finally, results are interpreted in terms of external forcings, such as geostrophic wind. As it is generally larger than the speed at crossing height, a 5 m s21 geostrophic wind may be considered as the typical limit below which sustainable, continuous turbulence under clear-sky conditions is unlikely to exist. Below this threshold emergence of the very stable nocturnal boundary layer is anticipated.

The minimum wind speed for sustainable turbulence in the nocturnal boundary layer

Reproducing the behavior of the mean variables that control the nocturnal atmospheric flow under very stable conditions is a very difficult task for atmospheric models. To understand the role of the surface scheme, turbulence scheme and radiation scheme on the performance of a single column model, its predictions are compared to observations collected at a very stable site located in deforested region in Amazon. The surface scheme takes on consideration the rapid changes in the surface energy budget caused by the presence of a vegetated layer over the soil. The turbulence scheme uses four different formulations for the mixing length. Two of them allow the existence of turbulence over the critical Richardson number, while the other two restrict dramatically the turbulence activity in those situations. The radiative scheme considers a clear sky condition, and evaluates the radiative flux divergence between 3 levels within the vertical domain: near the surface, at the domain top, and at the middle point between them. The predictions of all mixing length formulations are very similar to the observed data near the surface, indicating that in this region the surface plays a crucial role. At upper levels the most turbulent formulations lead to better results. This is a consequence of atmospheric decoupling when the turbulence is completely suppressed, which leads to colder results near the surface and warmer results aloft. The radiative scheme reproduces quite well the temperature decay above the boundary layer for all cases, in spite of its simplicity. On the other hand, the comparison between modeled and observed humidity profiles shows that it is necessary to improve the model by including a more complete scheme for humidity and by adding a advection scheme to it.

Quantification of Air Pollution in Kigali City and Its Environmental and Socio-Economic Impact in Rwanda

As global warming and climate change issues are defying modern society sustainable development; biofuels, biodiesel included, are among promising solutions. Biodiesel is generally produced from renewable vegetable oils and animal fats via acid or base catalyzed transesterification. Depending on regional availability, biodiesel production feedstocks vary from vegetable oils such as rapeseed oil, soya oil, palm oil, and jatropha oil, to used cooking oil and animal fats, with each type of feedstock presenting its own process challenges rooting from its chemical composition. This paper reports about biodiesel production from crude palm oil on a pilot plant scale, subsequent to a laboratory scale investigation of biodiesel synthesis from various vegetable oil feedstocks. Prior to transesterification, pretreatment processes have been applied due to the fact that crude palm oil as a biodiesel feedstock possesses a high free fatty acid(FFA) content, water, solid impurities and waxes, all of which hinder an efficient transesterification if not dealt with accordingly. Those processes are mainly filtering, water evaporation, and FFA esterification which is done with 99.9% methanol and 96% sulfuric acid as a catalyst. In fact, the acid esterification process successfully handles the raw palm oil despite its high FFA content of 16.9%, and biodiesel is produced from that feedstock with a yield of 90.4%. A two steps transesterification is carried out using potassium methylate 32% in methanol as a catalyst and anhydrous methanol too. Laboratory analyses have also been used to monitor the process and assess the final product quality. Furthermore, biodiesel cold filtering and top layer intake tank systems of a filling station, both proved to be efficient at helping to obtain a refined product by getting rid of suspensions appearing in biodiesel at room temperature due to sterol glucosides and waxes.

/pdf/biodiesel-production-from-unrefined-palm-oil-on-pilot-plant-45dt7xt70f.pdf

Biodiesel Production from Unrefined Palm Oil on Pilot Plant Scale

To compare both levels of water and air pollutants in Kigali city and Kitabi and benefits/disadvantages of the fuel types (gasoline, diesel and biodiesel) that are used in Rwanda, a parallel study on water and air pollution was conducted in Kigali city and Kitabi-Nyamagabe District during the January-July 2013 period. All vehicles entering Kigali City via Giticyinyoni, Nyacyonga, Gahanga and Rugende axes and the total number of motor vehicles in Rwanda were recorded. Carbon dioxide (CO2), carbon monoxide (CO), unburned hydrocarbons (HC) and opacity are the main emissions parameters measured at the Rwanda National Police Motor-vehicle Inspection Centre. The air quality parameters measured include HCl, NO2, NO3, SO2, H2S, TVOC, O3, CO and CO2 while quality of rain water harvested from the study sites was determined by measuring pH, conductivity, total dissolved solids, turbidity, biochemical oxygen demand, organic matter, sulfates, aluminum, copper, iron, manganese, cadmium, chromium, lead, sodium, and oils and grease. Kigali capital city suffers tremendous pressure of increasing population accompanied with the rapid increase in the number of vehicles which emit 526327.1 tons of CO2 year -1 , 18405.5 tons of CO year -1 and 354967.0 m 3 of unburned hydrocarbons year -1 . Using 100% biodiesel reduced emission of CO by 50% and opacity by 76.9%, while using a 50% biodiesel blend or biodiesel-diesel mixture (B50) reduced CO by 35.2% and opacity which is strongly correlated with properties of particulate air pollutants by 71%. In Kitabi area, HCl, N02, TVOC, 03, CO2, NO3, SO2 and CO were reduced by 76.6%, 54.6%, 74.8%, 72.7%, 100%, 100% and 100% as compared with Kigali city respectively. Levels of acidic air pollutants (SO2 and NO2) are negatively correlated with rain water acidity (pH) levels (SO2: r = 0.787; NO2: r = 0.734) implying, therefore, that atmospheric deposition of strong acids or acidic pollutants lowers the water pH levels or increase water acidity. Reductions in atmospheric deposition of strong acids and other toxic pollutants may result in some improvements in the acid-base status of some water bodies which can lead to increased growth conditions for various organisms. The use of cleaner energies (i.e. biodiesel) therefore, may be a practical option of controlling emissions or managing air pollution causes. More detailed studies, however, are needed to determine the contribution (quantitative and qualitative) of each source of pollutants to both air and water pollution in Rwanda and identify other key emission control measures to be undertaken. Also efficiency of photosynthetic process of trees that are commonly planted in Kigali city needs urgent investigation.

/pdf/comparative-levels-of-water-and-air-pollutants-in-kigali-2o4qy5tebj.pdf

Theoneste Ishimwe

Papers

Quantification of Air Pollution in Kigali City and Its Environmental and Socio-Economic Impact in Rwanda

Biodiesel Production from Unrefined Palm Oil on Pilot Plant Scale

Comparative Levels of Water and Air Pollutants in Kigali City and Kitabi and Benefits of Cleaner Energy-Biodiesel in Rwanda