Within Indiana, the overall increase in natural gas consumption, coupled with the use of natural gas for the generation of electricity, have significantly increased the demand for gas. The production of coal bed methane will help provide additional indigenous natural gas house hold and industrial uses and for generating power in the state.CBM recovery also can enhance the safety of underground coal mines by reducing the amount of methane present in the coal. In the past, methane in the in underground coal mines caused explosions resulting in the loss of life and considerable economic damage. Methane control during underground mining is mandated, thus increasing safety and providing the added benefit of producing an energy resource.MM Considering concerns about the impact on Indianan air quality resulting from the burning of coal for electrical power, CBM may prove to be cleaner energy resource derived from the state‘s abundant reserves of coal. During the production of the CBM, ground water is extracted from coal seam aquifers to facilitate the release of methane gas tapped under hydrostatic pressure. Development of new CBM fields typically generate large volumes of water that may represent an opportunity for operators to provide themselves, the landowner, and nearby industry with water that not result in the waste of this resource. The ability of CBM operator to provide CBM produced water for he water produced from CBM wells varies from very high quality (meeting state and federal drinking water standards) to le quality, essentially unusable ( with total dissolved solids [TDS] concentration up to 180000 parts per million). Currently, the management of CBM produced water is conducted using various water management practices depending on the quality of the produced water. In areas where the produced water is relatively fresh, the produced water is handled by a wide range of activities including direct discharge, storage in impoundments, livestock watering, irrigation, and dust control. In areas where the water quality is not suitable for direct use, operators use various treatments prior to discharge, and/or injection wells to dispose of the fluids The use of CBM produced water for beneficial use represents a flexible and valuable approach to utilizing an important resource by providing benefits to operators, land owners, and in some cases the general public. The quality of the produced water, the surrounding environmental setting, operator and land owner needs, and pertinent regulations, will often dictate the water’s designated use. In most cases certain aspects of development can benefit either by practical resolution or by satisfying public request or needs. Beneficial usage for CBM produced water has been integrated.
Abstract—The coal bed methane is methane mainly and it has less heavier than conventional natural gas, thus coal bed methane has a slightly higher value than natural gas. Developing and utilization of coal bed methane is an important way to release contraction between supply and demand of natural gas in China. The pipeline is principle way of transporting the coal bed methane from sources to end-users. In view of the characteristics of coal bed methane, equation of state BWRS is used to calculate the thermodynamic parameters. Then based on continuity equation, momentum equation, characteristic equations of non-pipe elements and flow quantity balance equation, the transient simulation mathematic model of coal bed methane transmission pipeline is built. Considering the slow transient characteristic of gas flowing, the implicit central difference method is used to transform partial differential equations of the model into finite difference equations. Aiming at non- linear characteristics of differential equations, Newton iteration format is constructed and the model’s solution method is discussed. Finally, MS Visual C++ is utilized to develop a simulation software name coal bed methane pipeline emulation system, and the practical applications are carried out. The results show the mathematic model built in the paper and its solving method are both feasible. They provide technical supports for reasonable design and operation of the coal bed methane pipelines.
and coal matrix. In this paper, the multi-point geo-statistical algorithm is applied for porosity and permeability modeling. Multiple-point geostatistical approaches (MPS) do not try to reproduce the training image itself, but they consist of extracting statistics of the variables from the training image statistics at multiple locations, and subsequently, using them to reproduce similar features to the training image. The principal component analysis (PCA) is applied to reduce the dimension of the pattern. The advantage of the PCA is that it can map the data in different principal components (PCs) which are normal to each other. The k-means clustering algorithm is applied for classifying the PCs of pattern database.
phase-transition fracturing (LCPF) technology through cross-boreholes in bottom drainage roadway. The results showed that the diameter of the borehole is obviously increased, and the gas flow rate and gas concentration are greatly enhanced, which indicates that the pores and fractures of the coal reservoir are effectively connected, and the influence radius of gas extraction is about 10m. Although, at the later stage of gas drainage period, the pure gas quantity and gas concentration show a decay trend, they still maintained at a high level, which is favorable for CBM extraction. Compared with hydraulic fracturing, the LCPF technology has better effect on permeability enhancement of coal seam in the early drainage stage after fracturing. The LCPF technology not only enhance the CBM extraction efficiency, but also shorten the driving period of roadways.
confirmed for low and high rank coal and for organic-rich shales of different origin (Chalmers and Bustin, 2007). With increasing coalification, thermal cracking of n-alkanes, waxes, and other hydrocarbons not only generates thermogenic methane but increases methane adsorptive capacity by unplugging pores, resulting in higher sorption capacity and gas content values since methane accessibility to the micropore network is improved (Scott, 2002). Controversially, in the San Juan Basin, lower rank coals have higher gas contents than higher rank coals (Scott, 2002). In this hydrogeological settings, weathering process introduced bacteria into the coal beds that produced secondary biogenic gases by metabolizing wet gases, n-alkanes, and other hydrocarbons generated during coalification (Scott, 2002). The generation of secondary biogenic gases increases gas contents beyond that expected from coal rank and if generated in sufficient quantities can actually resaturate the coal to the sorption isotherm (Scott et al., 1994). Overall, despite the similarities between shale and coal, the direct comparison of sorption characteristics of the two rocks is complicated by factors such as type and amount of OM, the mineral composition, pore volume and pore size distribution (Ross and Bustin, 2009). The controls on resource volume and productivity in SG reservoirs are similar to those in CBM, although SG reservoirs typically have lower permeability (with values in the nano- to microdarcy range), are thicker (30 to 300 ft), have lower sorbed-gas content (<10 m 3 /tonne), and contain a larger volume of
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The recovery rate of coalbed methane (CBM) can reflect the mining situation and the residual gas in coal reservoir. It plays an important role in the calcula- tion of the recoverable resources. This paper mainly uses isothermal adsorp- tion curve method and hydraulic model method to predict recovery rate of CBM. The isothermal adsorption curve method considering desorption lag problem in the prediction process, which is more in line with the actual situa- tion. In the hydraulic model method, the recovery rate of “V” type well is the largest in the early stage. But with the time going on, the recovery rate of mul- tilateral horizontal well is greater than vertical well, “U” type well and “V” type well finally. The factors affecting CBM recovery rate include geological characteristics, development conditions and economic factors. The geological characteristics of coal reservoir are the main factors affecting CBM recovery rate, and corresponding measures can be adopted to improve the recovery rate.
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Transforming multi-wavelet decomposition results of seismic trace near wells into the amplitude spectrum shown in Figure 5, it is found that the spectrum characteristics of coal bed is strong energy, high frequency and broad bandwidth, and that of both of thin interbedded sandstone and large thick sandstone is medium-to-strong energy and medium-to-high frequency as well as that of single thin sandstone being characterized by weak energy, low frequency and narrow bandwidth. The main frequency of energy group the is the corresponding frequency at the strongest energy in the time-frequency spectrum, and oblateness is the ratio of bandwidth of energy group to time thickness. Results of statistics and analyzing on time-frequency spectrum of all wells in the study area reveals that the main frequency has a fitting relation of power function with oblateness, which is shown in Figure 6. The fitting formula is as follows,
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Abstract. Based on the problems that coal bed methane (CBM) wells had no or low productions after fracturing, this paper combine the knowledge of logging technology, hydraulic fracturing technology, dewatering technology, optimization theory and artificial neural networks(ANN), a method of fracture effect forecast of CBM wells based on Kernel function of nonlinear principal component analysis (KPCA) and ANN is presented. This paper introduces the KPCA, ANN algorithm and sums up the influence of CBM well fracturing effect of the main factors. Through the method to the input of the model parameters were analyzed and the main parameters of the extraction, and based on this, established the ANN prediction model, and presents a case analysis. Application shows that the KPCA method combined with BP artificial neural network prediction of CBM well fracturing effect, simplified network structure, improve the computational speed, good practicability and reliability, is a worthy of promotion methods.
coal basins were discovered so far in Bangladesh, namely Barapukuria, Jamalganj, Khalaspir, Dighipara and Phulbari (Uddin and Islam 1992; Islam, 1994; Akhtar, 2000), and estimated reserve of coal is about 3 billion tons (Farhaduzzaman et al., 2013). The Barapukuria Basin is located at Dinajpur district in Bangladesh, which is the only active coal mine in the country. Six major coal seams are identified in the basin and coal extraction is going on in the coal seam VI of approximately 42 m thickness (Hossain et al., 2013a, b; Imam, 2013). Coal is an important source rock for both natural gas and crude oil (Petersen, 2006). Available information on the hydrocarbon potential of Gondwana coal in Bangladesh is limited. The present study attempts to improve the understanding of the generic potential (GP), coal bed methane (CBM) generation and underground coal gasification (UCG) through organic geochemical investigation of Permian Gondwana coals in the Barapukuria Basin, northwestern Bangladesh. Structure and stratigraphy. The Bengal Basin of Bangladesh has been developed since the Early Cretaceous, following the breakup of Gondwanaland, and sedimentation has been continuous ever since (Banerji, 1981; Gani and Alam, 2004; Hossain et al., 2010). The Barapukuria Basin is a sub-basin of the Bengal Basin covering an area of approximately 6.75 km 2
The reactor was filled with 12-17 kg bed materials in each test, which was fluidized by the primary air (around 185 L/min) and was heated up to above 750ºC for 1-2 hours using propane gas before introducing the solid fuels. A combustion mode was initially performed at an air-to-fuel ratio of 1.4 with a feed rate of about 8 kg/h of the fuel to warm up the whole system before the unit was switched to gasification mode. When a relatively stable bed temperature profile was reached, the gasification mode was started by increasing feed rate to 10-25 kg/h and decreasing total air flow rate to around 300 L/min to match the desired equivalence ratio (ER). In oxygen/air-blown gasification, ER has been commonly used as an important operating parameter, defined as the ratio of oxygen content of air supply to oxygen required for complete combustion (Devi et al., 2003).The value of ER has been observed to strongly influence the gas product compositions and gasification efficiency for air-blown biomass gasification (Kinoshita et al., 1994; Narváez et al., 1996). Usually, the ER is in a range from 0.2 to 0.4 for biomass gasification, to avoid incomplete gasification and excessive char formation at an excessively low ER (<0.2) as well as to prevent formation of incombustible gases like CO 2 , and H 2 O at an
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morbidity (Oberdörster, 2001; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010; Kumar et al., 2010; Lim et al., 2012). Despite significant effort made by several authors associating nanoparticles with severe health impacts, fewer studies have been done to investigate the morphology of particles, from packed-bed domestic coal combustion (i.e. shape, size and chemical properties) (Li et al., 2003; Kocbach et al., 2005; Torvela et al., 2014; Zhang et al., 2018). In addition to the health risks, combustion particles have been associated with environmental impacts (Chakrabarty et al., 2010; Chung, Ramanathan and Decremer, 2012). Sub-micron particles are often enriched with black carbon/ brown carbon, which contributes to the physicochemical processes occurring in the troposphere. Combustion particles from low-temperature combustion can absorb solar radiation from the sun (Chakrabarty et al., 2010; Liu et al., 2014; Tóth et al., 2014a). Furthermore, combustion particles also contribute to the light scattering effects, and provide an active site for the uptake of several chemical species and trace gases(Bond et al., 2002; Hand et al., 2005; Gwaze, 2007). In combustion sciences, more emphasis has been placed on the characterization of emissions of sub- micron particles in the transport sector and large-scale combustion processes such as power plants (Streets and Waldhoff, 2000; Petaloti et al., 2006; Meij and Winkel, 2007). However, very few studies to date have studied the morphology of particles emitted from small scale coal combustion technologies even though significant associated risks have been reported in countries like China, India and Finland (Zhang et al., 2000; He, Liang and Jiang, 2002; Niemi et al., 2006; An et al., 2007; Smith et al., 2007; Wilkinson et al., 2009; Chafe et al., 2015).
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Boiler in Indonesia’s steam power plant generally designed to use high range coal. The lack of supply make consumption shift to low range coal with moisture content 30-60 %. Using of this type will gives impact on increasing of flue gas, utilization of equipment, SOx and NOx pollution, self-ignition risk and cost of transport, handling and maintenance, otherwise will reduce efficiency, energy output and reliability and activate all of pulveriser. Upgrading coal calorific value can be done by several methods such drying, blending with higher calorific value and combination of drying and coating with oil residue.
An alternative method, the one used in this study was first used by Bond et al.  and entailed starting the combustion using a clean-burning, low-smoke fuel. The authors reported the use of Kingsford® barbeque briquettes, which have low particulate emissions during combustion. It was assumed that the emissions from the barbecue briquettes would cease before the first coal is burned. Wood kindling, on the other hand, showed high emissions that persisted into subsequent coal cycles. In our preliminary experiments, we found that pinewood had high particulate emissions at the start of ignition, but the emissions did not persist into subsequent coal cycles. Pinewood as a kindling was faster at igniting the coal compared to locally available barbeque compressed briquettes. We, therefore, used pinewood to initiate combustion so that the coal emissions could be isolated. Thus, the particle morphologies presented herein are representative of coal combustion smoke without being influenced by the kindling. However, to determine the total particulate matter attributable to coal combustion (e.g., to assess health effects or net effect of fuel switching) one should consider kindling emissions .
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The high adsorption capacity of fly ash permitted the elimination of suspended or soluble organic pollutants and removal of color from dyes wastewater. Also found that fly ash has good capacity of settling, which makes it possible to eliminate suspended solids by acting as a settling aid . Effluent sample of dyes was treated by means of adsorption process with briquettes of fly ash for the removal of effluent pollutants. The experimental study acknowledged that CFA adsorbent bed may possibly adsorb greatest proportion of pollutants such as color, COD, TSS and turbidity. It was concluded from coal fly ash adsorption study that it has greater affinity for pollutants of effluent. TSS removal through fly ash was found maximum. Dyes plant effluent was treated by means of adsorption process by the use of fly ash bed for the reduction of color, COD,TSS and turbidity. Adsorption capacity of CFA bed for COD, color, turbidity and TSS are shown below in (Fig. 8, 9, 10, 11), respectively.
Soon after, more efforts have been made in the design and process control of fluidized bed dry separator, leading to an abundance of patents and articles. For example, the method of cleaning coal and fluid separating medium was proposed by Levin et al. (Levin and Yost, 1938), and the schematic drawing is shown in Figure 2.2. The most prominent aspect of this invention is that the inclined wheel conveyors are employed to transport separated coal products, providing a stable product delivery rate. However, the immersed mechanism conveyors may also disturb the gravity separation process and lower the separation efficiency. Another fluidized bed coal cleaner was developed by Kendall et al. (Kendall and Moore, 1942), and the schematic diagram is displayed in Figure 2.3. The objectives of this design are to speed up the coal separation process and reduce the construction and operating costs. This fluidized bed coal cleaner is relatively small and inexpensive, which can be nearly standard constructed to adapt a great variety of operating conditions. The separation process in the apparatus can be sped up by feeding the raw coal into a rapidly fluidizing of sand and air, which can quickly float the clean coal away and drop the gangue to the bottom. Then, the clean coal and heavy refuse products can be readily withdrawn very soon. Furthermore, many other types of fluidized bed dry separators were developed for industrial practices (Holmes, 1934; Dickerson, 1935; Svensson, 1958). Their inventions focus more on the design and operation of fluidized bed dry separators, and the development of the basic principle and theory for the fluidized bed separation method was not studied in detail.
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The main components of Makarwal (Pakistan) coal are carbon, hydrogen, nitrogen, oxygen, ash and moisture contents (Table 1). The ultimate analysis was performed according to ISO 17247:2013 standard . The percentage composition of all the elements was checked by using automatic element analyser (Flash EA 1112, USA). The flow rates of carrier gas, oxygen and reference gas were set at 120, 220 and 100 mL/min respectively. The temperatures of oven were set at 900 and 70 °C . The elemental analyses were calculated at 1.8-2.0 mg with 0.002 mg precision. The standard deviation shows the three consecutive measurements of each sample. According to J. Lee et al., 2015, the absolute difference should be 0.20-0.32 % for carbon and 0.01-0.02% for hydrogen .
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After the accident of nuclear power plants in Fukushima, Japan, globally coal power plants has growing demand and number of new-built coal power plants has established. CO2 emissions are increased with the increasing of new coal power plants. The United States, which has 1,100 coal ash sites, produces 140 million tons of coal ash from coal-fired power plants every year. To reduce the landfill of coal ash, many countries have undertaken recycling of coal ash as key resources for recovery valuable critical rare earth elements and utilize the coal ash as construction material. One of our objectives was to evaluate the characteristics of hazardous heavy metals particularly mercury, arsenic, chromium and lead presented in coal combustion products (coal fly ash and bottom ash) from coal-fired power plants. The aim of this research was to identify and compare the technologies between Circulating Fluidized Bed Boiler (CFB) and Pulverized Coal-fired Boiler (PCB). In this study, coal and coal ash samples from different areas (Indonesia, Japan and Korea) are used for the evaluation of heavy metals concentration.
The evidence for three main routes to pollutant formation dur- ing co-combustion was evaluated. Firstly, the presence of high MW material indicates escape of devolatilisation products and partially reacted species from the combustion zone. Secondly, the emission factors of PAH, alkyl-PAH, oxygen-containing PAH (O-PAC) and phenols are consistent with pyrolysis products, while the high con- centrations of the two-ring (naphthalenes and indene) PAH precur- sors evidently arise through radical reactions involving cyclopentadiene intermediates from phenols generated by pyroly- sis of both coal and of biomass lignin. Thirdly, there is a contribu- tion from the hydrogen abstraction carbon addition (HACA) mechanism in which acetylene formed in the flame are added to smaller PAH radicals . A kinetic model was applied to coal, bio- mass and coal/biomass co-combustion and highlighted the role of HACA in soot production during biomass combustion, but this route to soot was insufficient to model the higher yields of soot observed during coal combustion. In this latter case, radical reac- tions involving either cyclopentadiene or condensation reactions of smaller PAH molecules initially formed in the pyrolysis stage to give aromers are more important.
It should be noted that mining bed 52 is characterized by complex conditions for gas emission management, which are characterized by the presence of upstream (in 40-45 m) and downstream (in 35-40 m) gas- bearing reservoirs with the capacity of 1.3 m and 1.9 m, respectively. The loads on the working face of 15-25 thousand tons/day achieved in the working areas in mining the bed predetermine a significant amount of methane released from the developed reservoir, and large volumes of gas from the mined-out space, related to gas release from these beds in the unloaded areas formed in the roof and the floor of mined-out spaces, and increased fracturing in the roof of the mined-out space. Thus, during intensive mining of bed 52, effective gas emission management in the working areas cannot be ensured by means of ventilation and insulated withdrawal with the use of traditional ventilation schemes and preparation of the working area without degassing. Thus, the use of degassing is a prerequisite of ensuring safety and efficiency of mining operations by the venting factor. A complicating factor is the presence of geological faults within the working area, in the zone of influence of which the absolute gas emission may reach 150-200 m 3 /min.
In the present coal handling plant there is no any kind of arrangement for the moist coal. If coal is contain 1% moisture then the flame stability get disturbed by 0.07% and the boiler efficiency get reduced by 0.1% to 0.2%. With increase in 1% moisture the CO2 emission get increase by 0.4%. In the present coal handling plant the conventional method is used to dry the coal that is coal is put in stock yard for 10-15 day to remove the surface moisture from the coal. By adopting this method only surface moisture is get removed to some extend but the other type of moisture cannot be removed here. To increase the efficiency of the plant it is necessary that the coal which plant using is free from moisture or contain less amount of moisture. There is also need to focus on the rate of moisture removed from the coal. The time required to remove the moisture should be less in order to achieved higher efficiency.