Papers by Keyword: Co-Firing

Abstract: Indonesia has implemented co-firing as a step for renewable energy utilization. Power plants in Northern Java could utilize wood waste from surrounding wood processing industries as co-firing fuel. In this study, wood waste with high value of ash fusion and stock coals of power plant were used as samples. Blended coals from stock coals are selected based on calorific value, slagging-fouling-abrasion prediction, and softening temperature prediction. Selected blended coals are mixed with wood waste in percentage of 10 wt% to 90 wt% to produce co-firing fuel which then predicted for risk tendency of slagging-fouling-abrasion by theoretical indices. The result shows that the addition of wood biomass increases the slagging, fouling, and abrasion tendency. In this study, addition of 20-30 wt% wood waste to blended coals can still be recommended with the medium risk of slagging-fouling and low risk of abrasion tendency.

Abstract: In order to study the combustion characteristics of sludge, coal, biomass and the mixed sample in micro-oxygen-rich environment (simulating micro-oxygen-rich environment with 30%O2/70%CO2), thermogravimetric analysis method is used in the paper. The experimental results show that under the micro-oxygen-rich environment, sludge has low ignition temperature, the average burning rate, burnout rate and flammability index, so combustion performance of sludge alone is poor and the weightlessness is more obvious in 200~600°C. But after mixing coal or biomass, combustion performance of sludge is improved. We use comprehensive application of flammability index and burnout characteristics index to determine the best mixing ratio is about 65% of sludge and coal, about 45% of sludge and biomass. Comprehensive combustion characteristic index may not be suitable for determining combustion performance of the sludge and its samples by comparison to S under the optimum mixing ratio of the sample and there are some errors. Biomass activation energy is the largest, the activation energy of sludge minimal. But the activation energy of the mixed sample doesn’t change regularly with the increase of sludge mixing proportion. So there is a deviation that we determine the mixing characteristics by a simple comparison of the activation energy of the samples. This paper provides a theoretical and data support for the selection and calculation of combustion parameters of mixed sludge and resource utilization of sludge.

Abstract: Burning fossil fuel like coal in power plants released carbon dioxide that had been absorbed millions of years ago. Unfortunately, excessive carbon dioxide emission had led to global warming. Malaysia, as one of the major exporters of palm oil, has abundant oil palm mill residues that could be converted into value-added product like biomass fuel briquettes. Fuel briquette with palm kernel shell and palm mesocarp fibre as its main ingredients showed satisfactory fuel characteristics and mechanical properties as a pure biomass fuel briquette. The effects of adding some coal of higher calorific value to the satisfactory biomass fuel briquette were focused in this study. Various coal-biomass fuel blends were used, ranging from 0wt% coal to 50wt% coal. The fuel properties and mechanical properties of pure biomass briquette and briquettes with different amount of coal added were compared experimentally. From the fuel properties tests, it was found that as the coal content in the briquette was increased, the carbon content and calorific value increased. Mechanical property tests on the fuel briquettes showed a mixture of results, with some favored higher portion of coal in the briquette for better handling, transport and storage properties while some favored greater amount of biomass.

Abstract: Co-firing has been adopted as a major approach for the efficient use of biomass as an energy source in large scale for two decades. Such a practice contributes to the decarbonisation in power generation sector and therefore to the mitigation of CO₂ emission. However, due to the differences in terms of thermal behaviors between biomass and coal, the co-firing of some biomasses with coal still presents many engineering problems, such as excessive fouling and slagging, which subsequently result in deteriorated boiler efficiency. The understanding of the transformation of minerals upon heating and how minerals originated in biomass affect ash fusion characteristics is of some significance for both design and operation purposes. In this study, low temperature ash (LTA) samples of biomass and coal were prepared and analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled energy diffraction spectrum (EDS), the results of which were compared with their corresponding high temperature ash (HTA) samples. The transformation of minerals upon heating was therefore studied. The ash fusion characteristic temperatures of ash samples derived from different biomass and coal blends were investigated. The ash fusion characteristic temperatures show some additive behaviors.

Abstract: Usage of planar microcoils in nuclear magnetic resonance (NMR) analysis of volume-limited chemical and biological samples has been widespread over the decades, since these microcoils obtain high sensitivity and resolution in localized units of volume. On the other hand, low-temperature co-fired ceramic (LTCC) materials exhibit highly reliable and advantageous properties in the radio frequency (RF) working area. In this work, author tries to incorporate this prosperous material technology in to design of high quality NMR microcoils, which were so far fabricated on the glass or polymer substrates. Set of few ceramic substrate microcoils is fabricated and characterized with detailed description of fabrication process in this paper.

Abstract: Combustion of coal, a fossil fuel, in power plant, is a major source of carbon dioxide emission, a greenhouse gas that causes global warming. Malaysia is one of the major exporters of palm oil and has 421 palm oil mills operating in 2010. Some of the residues from these mills like palm kernel shell and palm mesocarp fibre were converted into value-added products. An optimum biomass fuel briquette was obtained with palm kernel shell and palm mesocarp fibre as the major ingredients. Co-firing coal with biomass is a possible approach for power plant to curb the excessive emission of carbon dioxide. In this study, bio-briquette having 50% coal and 50% biomass which consisted of the ingredients of optimum biomass fuel briquette were studied in details. Comparison of the fuel properties, combustion characteristics and carbon dioxide emission between the optimum biomass fuel briquette and bio-briquette was made.

Abstract: Much attention has been paid to municipal solid waste (MSW) incineration power generation and biomass energy. The co-firing power generation tests of MSW and biomass were performed in a MSW incineration power plant in North China. Experimental results showed that the running efficiency of generator unit had achieved the optimum state when the blended ratio was 14% (w%); the concentration of fly ash decreased greatly, and the concentration of SO₂ and NO_X increased slightly. These contents can be referenced in the running of MSW incineration power plant and the using of biomass energy later.

Abstract: This study presented Computational Fluid Dynamic (CFD) analysis of the effect of co-firing coal blended with biomass, which is saw dust here. This complex problem which is because of its turbulent on the chemical reactions has been simulated in this paper for the purpose to decline the large amount of cost of doing experiment. The CFD analysis includes the prediction of vectors of the gas phase and DPM burnout result alike. What’s more, the reduction of CO2 by coal blended with different proportions of biomass has been presented because of low content of char in biomass. The mathematical models consist of models for turbulence flow(RNG K-EPSILON MODEL);non-premixed model with two mixture fractions/PDF model; and radiation (P-1 radiation model). The coal is from An Qin in China, and then respectively blended with 5% and 10% saw dust for co-combustion.

Abstract: Co-firing of biomass and coal has drawn many attentions because it can reduce the amount of CO2 release of the coal power plant/incinerator. However, the higher amount of sulfur, chlorine, potassium and calcium in biomass could lead to a more serious corrosion. In this study, the high-temperature corrosion of Fe-Cr-Mo alloy at 400 °C to 600 °C in co-firing of biomass and coal was performed. The results show that the weight change of specimen tested in co-firing of biomass and coal is 1.7 to 2.4 times of that for specimen tested in dry air. Also, the weight change of specimen tested in co-firing increased with the tested temperature and time increased. For the specimen tested in co-firing with different ratio of biomass/coal, the weight change of specimen increased with the ratio of biomass/coal increased.

Abstract: A novel rotary piezoelectric micro-motor (φ8mm×10mm) is proposed in this paper. Different from the conventional traveling wave ultrasonic motor using piezoelectric ceramic ring, four multilayer co-firing piezoelectric ceramic bulks (2mm×2mm×3mm) are used to generate vibration in the ring type stator. The layout and electric signals applied to the piezoelectric ceramic bulks are designed for the purpose of generating elliptical trajectories on the surface of the stator. The working mode of the prototype motor is simulated by the finite element method, and also measured by the Doppler Laser Vibrometer. The experimental results are in good agreement with simulation, which verifies the effectiveness of the finite element model. The prototype motor is driven at the low voltage of 12V under the frequency of 64.91 KHz.