Abstract: Forest fire, which is, an uncontrolled fire occurring in nature has become a major concern for the Forestry Commission of Ghana (FCG). The forest fires in Ghana usually result in massive destruction and take a long time for the firefighting crews to gain control over the situation. In order to assess the effect of forest fire at local scale, it is important to consider the role fire plays in vegetation composition, biodiversity, soil erosion, and the hydrological cycle. The occurrence, frequency and behaviour of forest fires vary over time and space, primarily as a result of the complicated influences of changes in land use, vegetation composition, fire suppression efforts, and other indigenous factors. One of the forest zones in Ghana with a high level of vegetation stress is the Goaso forest area. The area has experienced changes in its traditional land use such as hunting, charcoal production, inefficient logging practices and rural abandonment patterns. These factors which were identified as major causes of forest fire, have recently modified the incidence of fire in the Goaso area. In spite of the incidence of forest fires in the Goaso forest area, most of the forest services do not provide a cartographic representation of the burned areas. This has resulted in significant amount of information being required by the firefighting unit of the FCG to understand fire risk factors and its spatial effects. This study uses Remote Sensing and Geographic Information System techniques to develop a fire risk hazard model using the Goaso Forest Area (GFA) as a case study. From the results of the study, natural forest, agricultural lands and plantation cover types were identified as the major fuel contributing loads. However, water bodies, roads and settlements were identified as minor fuel contributing loads. Based on the major and minor fuel contributing loads, a forest fire risk hazard model with a reasonable accuracy has been developed for the GFA to assist decision making.
Abstract: Flow instability during gas lift operation is caused by three major phenomena – the density wave oscillation, the casing heading pressure and the flow perturbation within the two-phase flow region. This paper focuses on the causes and the effect of flow instability during gas lift operation and suggests ways to control it in order to maximise productivity during gas lift operations. A laboratory-scale two-phase flow system to study the effects of flow perturbation was designed and built. The apparatus is comprised of a 2 m long by 66 mm ID transparent PVC pipe with air injection point situated at 0.1 m above the base of the pipe. This is the point where stabilised bubbles were visibly clear after injection. Air is injected into the water filled transparent pipe at different flow rates and pressures. The behavior of the different sizes of the bubbles generated within the two-phase region was captured using a digital camera and the images were analysed using the advanced image processing package. It was observed that the average maximum bubbles sizes increased with the increase in the length of the vertical pipe column from 29.72 to 47 mm. The increase in air injection pressure from 0.5 to 3 bars increased the bubble sizes from 29.72 mm to 44.17 mm and then decreasing when the pressure reaches 4 bars. It was observed that at higher bubble velocity of 6.7 m/s, larger diameter bubbles coalesce and burst due to high agitation and collision with each other. This collapse of the bubbles causes pressure drop and reverse flow within two phase flow and is the main cause of the flow instability phenomena.
Abstract: Most thermal power plants use steam as working fluid in their power cycle. Therefore, in addition to fuel, water is the other main input for thermal plants. Water and steam must be highly pure in order to protect the systems from corrosion, scaling and biofouling. Pure process water is produced in water treatment plants having many several treatment methods. Treatment plant design is selected depending on raw water source and required water quality. Although working principle of fossil-fuel fired thermal power plants are same, there is no standard design and equipment arrangement valid for all thermal power plant utility systems. Besides that, there are many other technology evaluation and selection criteria for designing the most optimal water systems meeting the requirements such as local conditions, environmental restrictions, electricity and other consumables availability and transport, process water sources and scarcity, land use constraints etc. Aim of this study is explaining the adopted methodology for technology selection for process water preparation and industrial waste water treatment plant in a thermal power plant project located in Tufanbeyli, Adana Province in Turkey. Thermal power plant is fired with indigenous lignite coal extracted from adjacent lignite reserves. This paper addresses all above-mentioned factors affecting the thermal power plant water treatment facilities (demineralization + waste water treatment) design and describes the ultimate design of Tufanbeyli Thermal Power Plant Water Treatment Plant.
Abstract: Biological processes based on oxidation of sulfur
compounds by chemolithotrophic microorganisms are emerging as an
efficient and eco-friendly technique for removal of sulfur from the
coal. In the present article, study was carried out to investigate the
potential of biodesulfurization process in removing the sulfur from
lignite coal sample collected from a Mongolian coal mine. The batch
biodesulfurization experiments were conducted in 2.5 L borosilicate
baffle type reactors at 35 ºC using Acidithiobacillus ferrooxidans.
The effect of pulp density on efficiency of biodesulfurization was
investigated at different solids concentration (1-10%) of coal. The
results of the present study suggested that the rate of desulfurization
was retarded at higher coal pulp density. The optimum pulp density
found 5% at which about 48% of the total sulfur was removed from
the coal.
Abstract: This research aimed to study the influences of a soot blowing operation and geometrical variables to the stress characteristic of water wall tubes located in soot blowing areas which caused the boilers of Mae Moh power plant to lose their generation hour. The research method is divided into 2 parts (a) measuring the strain on water wall tubes by using 3-element rosette strain gages orientation during a full capacity plant operation and in periods of soot blowing operations (b) creating a finite element model in order to calculate stresses on tubes and validating the model by using experimental data in a steady state plant operation. Then, the geometrical variables in the model were changed to study stresses on the tubes. The results revealed that the stress was not affected by the soot blowing process and the finite element model gave the results 1.24% errors from the experiment. The geometrical variables influenced the stress, with the most optimum tubes design in this research reduced the average stress from the present design 31.28%.
Abstract: Effective treatment of ground instability is essential when managing the impacts associated with historic mining. A field trial was undertaken by the Coal Authority to investigate the geotechnical performance and potential use of composite materials comprising resin and fill or stone to safely treat surface collapses, such as crown-holes, associated with shallow mining. Test pits were loosely filled with various granular fill materials. The fill material was injected with commercially available silicate and polyurethane resin foam products. In situ and laboratory testing was undertaken to assess the geotechnical properties of the resultant composite materials. The test pits were subsequently excavated to assess resin permeation. Drilling and resin injection was easiest through clean limestone fill materials. Recycled building waste fill material proved difficult to inject with resin; this material is thus considered unsuitable for use in resin composites. Incomplete resin permeation in several of the test pits created irregular ‘blocks’ of composite. Injected resin foams significantly improve the stiffness and resistance (strength) of the un-compacted fill material. The stiffness of the treated fill material appears to be a function of the stone particle size, its associated compaction characteristics (under loose tipping) and the proportion of resin foam matrix. The type of fill material is more critical than the type of resin to the geotechnical properties of the composite materials. Resin composites can effectively support typical design imposed loads. Compared to other traditional treatment options, such as cement grouting, the use of resin composites is potentially less disruptive, particularly for sites with limited access, and thus likely to achieve significant reinstatement cost savings. The use of resin composites is considered a suitable option for the future treatment of shallow mining collapses.
Abstract: By GEO5 FEM program with four rockfill slope
modeling and stability analysis was performed for S1, S2, S3 and
S4 slopes where landslides of the shalefills were limited. Effective
angle of internal friction (φ'°) 17°-22.5°, the effective cohesion (c')
from 0.5 to 1.8 kPa, saturated unit weight 1.78-2.43 g/cm3, natural
unit weight 1.9-2.35 g/cm3, dry unit weight 1.97-2.40 g/cm3, the
permeability coefficient of 1x10-4 - 6.5x10-4 cm/s. In cross-sections
of the slope, GEO 5 FEM program possible critical surface tension
was examined. Rockfill dump design was made to prevent sliding
slopes. Bulk material designated geotechnical properties using also
GEO5 programs FEM and stability program via a safety factor
determined and calculated according to the values S3 and S4 No.
slopes are stable S1 and S2 No. slopes were close to stable state
that has been found to be risk. GEO5 programs with limestone rock
fill dump through FEM program was found to exhibit stability.
Abstract: The sun is an inexhaustible source and harness its potential both for heating and power generation is one of the most promising and necessary alternatives, mainly due to environmental issues. However, it should be noted that this has always been present in the generation of energy on earth, only indirectly, since it is responsible for virtually all other energy sources, such as generating source of evaporation of the water cycle, allowing the impoundment and the consequent generation of electricity (hydroelectric power); winds are caused by atmospheric induction caused by large scale solar radiation; petroleum, coal and natural gas were generated from waste plants and animals that originally derived energy required for their development of solar radiation. This paper presents a study on the feasibility of using solar energy for water heating in homes. A simplified methodology developed for formulation of solar heating operation model of water in alternative systems of solar energy in Brazil, and compared it to that in the international market. Across this research, it was possible to create new paradigms for alternative applications to the use of solar energy.
Abstract: Flue gas desulfurization gypsum (FGD) is a waste
material arouse from coal power plants. Hydroxyapatite (HAP) is a
biomaterial with porous structure. In this study, FGD gypsum which
retrieved from coal power plant in Turkey was characterized and
HAP particles which can be used as an adsorbent in wastewater
treatment application were synthesized from the FGD gypsum. The
raw materials are characterized by using X Ray Diffraction (XRD)
and Fourier transform infrared spectroscopy (FT-IR) techniques and
produced HAP are characterized by using XRD. As a result, HAP
particles were synthesized at the molar ratio of 5:10, 5:15, 5:20, 5:24,
at room temperature, in alkaline medium (pH=11) and in 1 hour-reaction
time. Among these conditions, 5:20 had the best result.
Abstract: For several hundred years, the design of railway tracks
has practically remained unchanged. Traditionally, rail tracks are
placed on a ballast layer due to several reasons, including economy,
rapid drainage, and high load bearing capacity. The primary function
of ballast is to distributing dynamic track loads to sub-ballast and
subgrade layers, while also providing lateral resistance and allowing
for rapid drainage. Upon repeated trainloads, the ballast becomes
fouled due to ballast degradation and the intrusion of fines which
adversely affects the strength and deformation behaviour of ballast.
This paper presents the use of three-dimensional discrete element
method (DEM) in studying the shear behaviour of the fouled ballast
subjected to direct shear loading. Irregularly shaped particles of
ballast were modelled by grouping many spherical balls together in
appropriate sizes to simulate representative ballast aggregates. Fouled
ballast was modelled by injecting a specified number of miniature
spherical particles into the void spaces. The DEM simulation
highlights that the peak shear stress of the ballast assembly decreases
and the dilation of fouled ballast increases with an increase level of
fouling. Additionally, the distributions of contact force chain and
particle displacement vectors were captured during shearing progress,
explaining the formation of shear band and the evolutions of
volumetric change of fouled ballast.
Abstract: Energy has a prominent role for development of
nations. Countries which have energy resources also have strategic
power in the international trade of energy since it is essential for all
stages of production in the economy. Thus, it is important for
countries to analyze the weaknesses and strength of the system. On
the other side, international trade is one of the fields that are analyzed
as a complex network via network analysis. Complex network is one
of the tools to analyze complex systems with heterogeneous agents
and interaction between them. A complex network consists of nodes
and the interactions between these nodes. Total properties which
emerge as a result of these interactions are distinct from the sum of
small parts (more or less) in complex systems. Thus, standard
approaches to international trade are superficial to analyze these
systems. Network analysis provides a new approach to analyze
international trade as a network. In this network, countries constitute
nodes and trade relations (export or import) constitute edges. It
becomes possible to analyze international trade network in terms of
high degree indicators which are specific to complex networks such
as connectivity, clustering, assortativity/disassortativity, centrality,
etc. In this analysis, international trade of crude oil and coal which
are types of fossil fuel has been analyzed from 2005 to 2014 via
network analysis. First, it has been analyzed in terms of some
topological parameters such as density, transitivity, clustering etc.
Afterwards, fitness to Pareto distribution has been analyzed via
Kolmogorov-Smirnov test. Finally, weighted HITS algorithm has
been applied to the data as a centrality measure to determine the real
prominence of countries in these trade networks. Weighted HITS
algorithm is a strong tool to analyze the network by ranking countries
with regards to prominence of their trade partners. We have
calculated both an export centrality and an import centrality by
applying w-HITS algorithm to the data. As a result, impacts of the
trading countries have been presented in terms of high-degree
indicators.
Abstract: Coal fly ash, an industrial by product of coal
combustion thermal power plants is considered as a hazardous
material and its improper disposal has become an environmental
issue. On the other hand, manufacturing conventional clay bricks
involves on consumption of large amount of clay and leads
substantial depletion of topsoil. This paper unveils the possibility of
using fly ash as a partial replacement of clay for brick manufacturing
considering the local technology practiced in Bangladesh. The effect
of fly ash with different replacing ratio (0%, 20%, 30%, 40%, and
50% by volume) of clay on properties of bricks was studied. Bricks
were made in the field parallel to ordinary bricks marked with
specific number for different percentage to identify them at time of
testing. No physical distortion is observed in fly ash brick after
burning in the kiln. Results from laboratory test show that
compressive strength of brick is decreased with the increase of fly
ash and maximum compressive strength is found to be 19.6 MPa at
20% of fly ash. In addition, water absorption of fly ash brick is
increased with the increase of fly ash. The abrasion value and
Specific gravity of coarse aggregate prepared from brick with fly ash
also studied and the results of this study suggests that 20% fly ash
can be considered as the optimum fly ash content for producing good
quality bricks utilizing present practiced technology.
Abstract: South Africa is in its post-industrial era moving from
the primary and secondary sector to the tertiary sector. The study
investigated the impact of the disaggregated energy consumption
(coal, oil, and electricity) on the primary, secondary and tertiary
sectors of the economy between 1980 and 2012 in South Africa.
Using vector error correction model, it was established that South
Africa is an energy dependent economy, and that energy (especially
electricity and oil) is a limiting factor of growth. This implies that
implementation of energy conservation policies may hamper
economic growth. Output growth is significantly outpacing energy
supply, which has necessitated load shedding. To meet up the excess
energy demand, there is a need to increase the generating capacity
which will necessitate increased investment in the electricity sector as
well as strategic steps to increase oil production. There is also need to
explore more renewable energy sources, in order to meet the growing
energy demand without compromising growth and environmental
sustainability. Policy makers should also pursue energy efficiency
policies especially at sectoral level of the economy.
Abstract: Cryosorption pumps are considered safe, quiet, and
ultra-high vacuum production pumps which have their application
from Semiconductor industries to ITER [International Thermonuclear
Experimental Reactor] units. The principle of physisorption of gases
over highly porous materials like activated charcoal at cryogenic
temperatures (below -1500°C) is involved in determining the
pumping speed of gases like Helium, Hydrogen, Argon, and
Nitrogen. This paper aims at providing detailed overview of
development of Cryosorption pump and characterization of different
activated charcoal materials that optimizes the performance of the
pump. Different grades of charcoal were tested in order to determine
the pumping speed of the pump and were compared with
commercially available Varian cryopanel. The results for bare panel,
bare panel with adhesive, cryopanel with pellets, and cryopanel with
granules were obtained and compared. The comparison showed that
cryopanel adhered with small granules gave better pumping speeds
than large sized pellets.
Abstract: This paper studies a mathematical model based on the
integral equations for dynamic analyzes numerical investigations of a
non-uniform or multi-material composite beam. The beam is
subjected to a sub-tangential follower force and elastic foundation.
The boundary conditions are represented by generalized
parameterized fixations by the linear and rotary springs. A
mathematical formula based on Euler-Bernoulli beam theory is
presented for beams with variable cross-sections. The non-uniform
section introduces non-uniformity in the rigidity and inertia of beams
and consequently, more complicated equilibrium who governs the
equation. Using the boundary element method and radial basis
functions, the equation of motion is reduced to an algebro-differential
system related to internal and boundary unknowns. A generalized
formula for the deflection, the slope, the moment and the shear force
are presented. The free vibration of non-uniform loaded beams is
formulated in a compact matrix form and all needed matrices are
explicitly given. The dynamic stability analysis of slender beam is
illustrated numerically based on the coalescence criterion. A realistic
case related to an industrial chimney is investigated.
Abstract: This paper reports the viability of developing Zn-27Al
alloy matrix hybrid composites reinforced with alumina, graphite and
fly ash (solid waste bye product of coal in thermal power plants).
This research work was aimed at developing low cost-high
performance Zn-27Al matrix composite with low density. Alumina
particulates (Al2O3), graphite added with 0, 2, 3, 4 and 5 wt% fly ash
were utilized to prepare 10wt% reinforcing phase with Zn-27Al alloy
as matrix using two-step stir casting method. Density measurement,
estimated percentage porosity, tensile testing, micro hardness
measurement and optical microscopy were used to assess the
performance of the composites produced. The results show that the
hardness, ultimate tensile strength, and percent elongation of the
hybrid composites decrease with increase in fly ash content. The
maximum decrease in hardness and ultimate tensile strength of
13.72% and 15.25% respectively were observed for composite grade
containing 5wt% fly ash. The percentage elongation of composite
sample without fly ash is 8.9% which is comparable with that of the
sample containing 2wt% fly ash with percentage elongation of 8.8%.
The fracture toughness of the fly ash containing composites was
however superior to those of composites without fly ash with 5wt%
fly ash containing composite exhibiting the highest fracture
toughness. The results show that fly ash can be utilized as
complementary reinforcement in ZA-27 alloy matrix composite to
reduce cost.
Abstract: The world crude oil demand is projected to rise to 108.5 million bbl/d by the year 2035. With reserves estimated at 869 billion tonnes worldwide, coal remains an abundant resource. The aim of this work was to produce a high value hydrocarbon liquid product using a Direct Coal Liquefaction (DCL) process at, relatively mild operating conditions. Via hydrogenation, the temperature-staged approach was investigated in a dual reactor lab-scale pilot plant facility. The objectives included maximising thermal dissolution of the coal in the presence of tetralin as the hydrogen donor solvent in the first stage with 2:1 and 3:1 solvent: coal ratios. Subsequently, in the second stage, hydrogen saturation, in particular, hydrodesulphurization (HDS) performance was assessed. Two commercial hydrotreating catalysts were investigated viz. NickelMolybdenum (Ni-Mo) and Cobalt-Molybdenum (Co-Mo). GC-MS results identified 77 compounds and various functional groups present in the first and second stage liquid product. In the first stage 3:1 ratios and liquid product yields catalysed by magnetite were favoured. The second stage product distribution showed an increase in the BTX (Benzene, Toluene, Xylene) quality of the liquid product, branched chain alkanes and a reduction in the sulphur concentration. As an HDS performer and selectivity to the production of long and branched chain alkanes, Ni-Mo had an improved performance over Co-Mo. Co-Mo is selective to a higher concentration of cyclohexane. For 16 days on stream each, Ni-Mo had a higher activity than Co-Mo. The potential to cover the demand for low–sulphur, crude diesel and solvents from the production of high value hydrocarbon liquid in the said process, is thus demonstrated.
Abstract: Coal tar is a liquid by-product of coal pyrolysis
processes. This liquid oil mixture contains various kinds of useful
compounds such as benzoic aromatic compounds and phenolic
compounds. These compounds are widely used as raw material for
insecticides, dyes, medicines, perfumes, coloring matters, and many
others. The coal tar was collected by pyrolysis process of coal
obtained from PT Kaltim Prima Coal and Arutmin-Kalimantan. The
experiments typically occurred at the atmospheric pressure in a
laboratory furnace at temperatures ranging from 300 to 550oC with a
heating rate of 10oC/min and a holding time of 1 hour at the pyrolysis
temperature. The Gas Chromatography-Mass Spectroscopy (GC-MS)
was used to analyze the coal tar components. The obtained coal tar
has the viscosity of 3.12 cp, the density of 2.78 g/cm3, the calorific
value of 11,048.44 cal/g, and the molecular weight of 222.67. The
analysis result showed that the coal tar contained more than 78
chemical compounds such as benzene, cresol, phenol, xylene,
naphtalene, etc. The total phenolic compounds contained in coal tar
are 33.25% (PT KPC) and 17.58% (Arutmin-Kalimantan). The total
naphtalene compounds contained in coal tar is 14.15% (PT KPC) and
17.13% (Arutmin-Kalimantan).
Abstract: A lower consumption of thermal energy will
contribute not only to a reduction in the running costs, but also in the
reduction of pollutant emissions that contribute to the greenhouse
effect. Cogeneration or CHP (Combined Heat and Power) is the
system that produces power and usable heat simultaneously by
decreasing the pollutant emissions and increasing the efficiency.
Combined production of mechanical or electrical and thermal energy
using a simple energy source, such as oil, coal, natural or liquefied
gas, biomass or the sun; affords remarkable energy savings and
frequently makes it possible to operate with greater efficiency when
compared to a system producing heat and power separately. This
study aims to bring out the contributions of cogeneration systems to
the environment and sustainability by saving the energy and reducing
the emissions. In this way we made a comprehensive investigation in
the literature by focusing on the environmental aspects of the
cogeneration systems. In the light of these studies we reached that,
cogeneration systems must be consider in sustainability and their
benefits on protecting the ecology must be investigated.
Abstract: Brownfields are one of the most important problems
that must be solved by today's cities. The topic of this article is
description of developing a comprehensive transformation of postindustrial
area of the former iron factory national cultural heritage
lower Vítkovice. City of Ostrava used to be industrial superpower of
the Czechoslovak Republic, especially in the area of coal mining and
iron production, after declining industrial production and mining in
the 80s left many unused areas of former factories generally
brownfields and backfields. Since the late 90s we are observing how
the city officials or private entities seeking to remedy this situation.
Regeneration of brownfields is a very expensive and long-term
process. The area is now rebuilt for tourists and residents of the city
in the entertainment, cultural, and social center. It was necessary do
the reconstruction of the industrial monuments. Equally important
was the construction of new buildings, which helped reusing of the
entire complex. This is a unique example of transformation of
technical monuments and completion of necessary new objects, so
that the area could start working again and reintegrate back into the
urban system.