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Influence of bed materials on the performance of the Nong Bua dual fluidized bed gasification power plant in Thailand
(2022-08-01)
Siriwongrungson, Vilailuck
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Hongrapipat, Janjira
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Kuba, Matthias
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Rauch, Reinhard
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Pang, Shusheng
Bed materials and their catalytic activity are two main parameters that affect the performance of the dual fluidized bed (DFB) gasification system in terms of product gas composition and tar levels. Two sources of bed materials were used for the operation of a commercial DFB gasification system in Thailand, using woodchips as a biomass feedstock. One source of the bed materials was the calcined olivine which had been used in the Gussing Plant, Austria, and the other activated bed material was a mixture of fresh Chinese olivine and used Austrian olivine with additives of biomass ash, calcium hydroxide and dolomite. These bed materials were collected and analysed for morphological and chemical composition using a scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray fluorescence spectroscopy (XRF). The product gas was cleaned in a scrubber to remove tars, from which the samples were collected for gravimetric tar analysis. Its composition data was automatically recorded at the operation site before it entered the gas engine. From the SEM, EDS and XRF analyses, calcium-rich layers around the bed materials were observed on the activated bed material. The inner layers of bed materials collected were homogeneous. Biomass ash, which was generally added to the bed materials, had significant calcium and potassium content. These calcium-rich layers of the bed materials, from the calcium hydroxide, biomass ash and dolomite, influenced system performance, which was determined by observing lower tar concentration and higher hydrogen concentration in the product gas.
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Influence of Gasification Operating Parameters on Performance of the Nong Bua Dual Fluidized Bed Gasification System in Thailand
(2022-01-01)
Prasong, Malinee
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Siriwongrungson, Vilailuck
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Hongrapipat, Janjira
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Rauch, Reinhard
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Pang, Shusheng
Gasification system performance generally depends on feed moisture content, activity of bed material, gasifier and combustor temperatures, and scrubber media. The tar concentration and gas composition of product gas are two indicators of the gasification system performance. In this research, the effects of gasifier temperature and the activity of bed material on the tar concentration and gas composition of the product gas produced from a dual fluidized bed (DFB) gasification system power plant were investigated. The DFB gasification system power plant is located in Nong Bua district, Nakhon Sawan province, Thailand. Two periods of gasification operation were examined. These two periods were when the olivine was freshy activated and then after a period of operation. The gasifier temperature had several peaks during the operation, which caused the product gas composition to fluctuate. When the olivine had been used for a period, the percentage of hydrogen was approximately 3% higher than when the olivine had been freshly activated, and a lower heating value was observed, which was probably due to lower heating value of hydrogen. The tar concentration was substantially lower when compared with the freshly activated olivine. When the olivine was used for a period, the average tar concentration was 56±22 mg/Nm3 (this is after 95 h continuous operating time) while the average tar concentration of the freshly activate olivine was 872±125 mg/Nm3 (which was after 34.5 h continuous operating time). It was concluded that the average tar concentration and gas composition were influenced by the activity of the bed material and the gasification temperature.
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Effect of the presence of HCl on simultaneous CO2 capture and contaminants removal from simulated biomass gasification producer gas by CaO-Fe2O3 sorbent in calcium looping cycles
(2021-12-01)
Dashtestani, Forogh
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Nusheh, Mohammad
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Siriwongrungson, Vilailuck
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Hongrapipat, Janjira
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Materic, Vlatko
This study investigated the effect of HCl in biomass gasification producer gas on the CO<inf>2</inf> capture efficiency and contaminants removal efficiency by CaO-Fe<inf>2</inf>O<inf>3</inf> based sorbent material in the calcium looping process. Experiments were conducted in a fixed bed reactor to capture CO<inf>2</inf> from the producer gas with the combined contaminants of HCl at 200 ppmv, H<inf>2</inf>S at 230 ppmv, and NH<inf>3</inf> at 2300 ppmv. The results show that with presence of HCl in the feeding gas, sorbent reactivity for CO<inf>2</inf> capture and contaminants removal was enhanced. The maximum CO<inf>2</inf> capture was achieved at carbonation temperatures of 680◦C, with efficiencies of 93%, 92%, and 87%, respectively, for three carbonation-calcination cycles. At this carbonation temperature, the average contaminant removal efficiencies were 92.7% for HCl, 99% for NH<inf>3</inf>, and 94.7% for H<inf>2</inf>S. The outlet contaminant concentrations during the calcination process were also examined which is useful for CO<inf>2</inf> reuse. The pore structure change of the used sorbent material suggests that the HCl in the feeding gas contributes to high CO<inf>2</inf> capture efficiency and contaminants removal simultaneously.
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Influence of solvent temperature and type on naphthalene solubility for tar removal in a dual fluidized bed biomass gasification process
(2021-10-01)
Tonpakdee, Pimnara
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Hongrapipat, Janjira
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Siriwongrungson, Vilailuck
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Rauch, Reinhard
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Pang, Shusheng
Tar condensation is a cause of blockage in downstream application of the gasification process. An oil scrubber is considered as an effective method for tar removal. In this research, the naphthalene solubility in different local Thai oils and water was investigated in a laboratory-scale test-rig. The solubility value was conducted at 30, 50, 70, and 80°C. Biodiesels investigated were rapeseed methyl ester (RME) and two different palm methyl esters (PME 1 and PME 2). Furthermore, vegetable oils including sunflower oil, rice bran oil, crude palm oil, and refined palm oil were examined. The results showed that higher temperature enhanced naphthalene solubility in all types of investigated oils. Biodiesel has the highest value of naphthalene solubility. All scrubbing oils have similar naphthalene solubility trends at the temperature range of 50-80°C in the order of RME > PME 1 > PME 2 > diesel > sunflower oil > refined palm oil > rice bran oil > crude palm oil. Based on these experimental investigations, PME 1 has a naphthalene solubility value similar to RME. Therefore, PME 1 has been selected to be tested as scrubbing solvent in the 1 MW<inf>el</inf> prototype dual fluidized gasifier located in Nong Bua district, Nakhon Sawan province, Thailand.
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Solubility of Tar Model Compounds in Various Solvents for Tar Removal in a Dual Fluidized Bed Biomass Gasification Process
(2021-08-09)
Tonpakdee, Pimnara
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Hongrapipat, Janjira
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Siriwongrungson, Vilailuck
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Pang, Shusheng
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Rauch, Reinhard
Production of high quality product gas via biomass steam gasification is a promising technology. However, impurities in the product gas, namely tars, cause problems in the downstream gas processing operations and thus they need to be removed efficiently. Oil scrubbing is an effective solution for tar removal due to its non-polar characteristic which is similar to tar nature. In this research, solubility values of five simulated tar compounds were experimentally investigated for selecting the new scrubbing solvent. The simulated tar compounds investigated represent those found in the dual fluidized bed steam gasification of wood biomass, which are: naphthalene, biphenyl, anthracene, fluoranthene, and pyrene. The scrubbing solvents tested in this research are classified into biodiesels, vegetable oils, and diesel. Biodiesel used are rapeseed methyl ester (RME) and 2 different palm methyl esters (denoted as PME1 and PME2). Vegetable oils are sunflower oil, refined palm oil, Thai rice bran oil, and crude palm oil. All of the solubility tests were performed in the laboratory-scale test-rig at 30, 50, 70, and 80°C. Biodiesels are found to be the effective solvent in dissolving the tar compounds. PME1 shows the similar tar removal performance to RME but is more readily available; therefore, PME1 is chosen to be used as a scrubbing solvent at the Thailand 1 MWel prototype DFB gasifier at Nong Bua district in Nakhon Sawan province, Thailand.
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Influence of processing parameters on the hydrogen storage properties of dip coated lithium alanate thin films
(2021-05-19)
Choawarot, Choosak
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Siriwongrungson, Vilailuck
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Hongrapipat, Janjira
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Pang, Shusheng
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Messner, Michael
The complex metal hydride materials have been researched and reported as an effective hydrogen storage material with the gravimetric hydrogen storage capacity of around 5-7 wt%. In this paper, the 20 mg/cm3 of lithium alanate solution prepared at 4 degree C and 25 degree C were dip coated on glass substrate. The post-annealing time was varied at 0 s, 1800 s and 3600 s. Phase and grain size were investigated using the X-ray powder diffraction. The hydrogen storage capacity and hydrogen desorption temperature were analyzed using thermogravimetric analysis. The lithium aluminium hydroxide hydrate and lithium hexahydroaluminate were observed on the deposited lithium alanate thin films when using the lithium alanate solution prepared at 4 degree C while only the lithium hexahydroaluminate was detected on the deposited lithium alanate thin films when the lithium alanate solution was prepared at 25 degree C. It was observed that the deposited lithium alanate thin films with lithium aluminium hydroxide hydrate have lower hydrogen storage capacity than the lithium alanate thin films without lithium aluminium hydroxide hydrate even the lithium alanate thin films with lithium aluminium hydroxide hydrate have smaller grain size. The hydrogen storage capacity and hydrogen desorption temperature of the deposited lithium alanate thin films were improved with longer annealing time.
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Characterization and hydrogen storage capacity analysis of dip coated lithium aluminium hydride thin films
(2021-01-01)
Choawarot, Chusak
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Siriwongrungson, Vilailuck
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Hongrapipat, Janjira
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Pang, Shusheng
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Messner, Michael
Complex metal hydrides are one of the most effective hydrogen storage materials due to their unique property to absorb and desorb hydrogen with the hydrogen storage capacity of about 5-7 wt%. In this study, lithium aluminium hydride (LiAlH4) was coated on glass substrate using dip coating method. The coating conditions investigated were LiAlH4 concentrations of 6 g/l, 10 g/l and 20 g/l and post-annealing time from 0 to 60 min. Phase and grain size of the deposited LiAlH4 were analyzed using X-ray powder diffraction (XRD). Scanning electron microscope (SEM) was used for surface morphology analysis. The hydrogen storage capacity of the deposited thin films was analyzed using thermogravimetric analysis (TGA). The experimental results revealed that the phase of the deposited LiAlH4 thin films on glass substrate were mixed with lithium aluminium hydroxide hydrate (LiAl2(OH)7·2H2O) and lithium hexahydroaluminate (Li3AlH6). The intensity of the LiAl2(OH)7·2H2O and LiAlH4 peaks tends to decrease with increasing LiAlH4 concentration and post-annealing time while the intensity of the Li3AlH6 peaks increased with increasing LiAlH4 concentration and post-annealing time. The grain size was decreased with increasing LiAlH4 concentration and post-annealing time. The smaller grain size the better the hydrogen storage capacity. The hydrogen storage capacity of the deposited LiAlH4 thin film was increased from 0.124 wt % using LiAlH4 concentration of 6 g/l without post-annealing to 1.675 wt % using LiAlH4 concentration of 20 g/l with 60 min post-annealing time.
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CO2Capture from Biomass Gasification Producer Gas Using a Novel Calcium and Iron-Based Sorbent through Carbonation-Calcination Looping
(2020-10-14)
Dashtestani, Forogh
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Nusheh, Mohammad
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Siriwongrungson, Vilailuck
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Hongrapipat, Janjira
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Materic, Vlatko
In this study, a novel sorbent material based on CaO and Fe2O3 was investigated for its performance in CO2 capture from simulated biomass gasification producer gas. Experiments were conducted in a fixed bed reactor and each run of the experiments included three major stages of sorbent material reduction, CO2 capture (carbonation), and CO2 release (calcination). The operation temperature in the CO2 capture stage was controlled at 590, 620, 650, and 680 °C, while the temperature for the CO2 release was maintained at 850 °C. The duration of the CO2 capture stage was 3 h and that of the CO2 release stage was 2 h. The effect of cycles of carbonation-calcination looping of the sorbent material was also investigated at the carbonation temperature of 650 °C. The experimental results show that effective CO2 capture by the sorbent material occurred in the initial 20 min during the carbonation. In the calcination stage, the rate of CO2 release reached the peak in 30-40 min from the start of the calcination. The carbonation temperature has a significant effect on CO2 capture and the optimum carbonation temperature was found to be 620 °C, at which CO2 capture efficiency was 94% for the first cycle and 90.4% as average for the first three cycles. It was also found that the CO2 capture efficiency was reduced with cycling. Mechanisms of the CO2 capture and the effect of cycling were also examined.
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Polymeric materials and films in dentistry: An overview
(2018-11-01)
Rokaya, Dinesh
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Srimaneepong, Viritpon
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Sapkota, Janak
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Qin, Jiaqian
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Siraleartmukul, Krisana
The use of polymeric materials (PMs) and polymeric films (PMFs) has increased in medicine and dentistry. This increasing interest is attributed to not only the excellent surfaces of PMs and PMFs but also their desired mechanical and biological properties, low production cost, and ease in processing, allowing them to be tailored for a wide range of applications. Specifically, PMs and PMFs are used in dentistry for their antimicrobial, drug delivery properties; in preventive, restorative and regenerative therapies; and for corrosion and friction reduction. PMFs such as acrylic acid copolymers are used as a dental adhesive; polylactic acids are used for dental pulp and dentin regeneration, and bioactive polymers are used as advanced drug delivery systems. The objective of this article was to review the literatures on the latest advancements in the use of PMs and PMFs in medicine and dentistry. Published literature (1990–2017) on PMs and PMFs for use in medicine and dentistry was reviewed using MEDLINE/PubMed and ScienceDirect resources. Furthermore, this review also explores the diversity of latest PMs and PMFs that have been utilized in dental applications, and analyzes the benefits and limitations of PMs and PMFs. Most of the PMs and PMFs have shown to improve the biomechanical properties of dental materials, but in future, more clinical studies are needed to create better treatment guidelines for patients.
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Influence of thickness of p-type diamond Hall sensors synthesized by HFCVD on their response sensitivity to magnetic field
(2018-07-02)
Panyalert, Wasin
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Siriwongrungson, Vilailuck
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Suwanna, Prapakron
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Titiroongruang, Wisut
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Niemcharoen, Surasak
This article presents the study of the influence of thickness of p-type diamond Hall sensors, which were synthesized by HFCVD, on their response sensitivity to magnetic field. Boron was added in ethyl alcohol as the reactant to obtain p-type diamond film at B/C ratio of 10,000 ppm. The synthesis durations of 6, 12 and 36 hours at the substrate temperature of 750°C were selected to achieve the required diamond film thicknesses of 50, 100 and 150 µm, respectively. The synthetic diamond films were confirmed to be diamond using Raman spectroscopy and the cross sections were analyzed using SEM (Scanning Electron Microscopy). Then, simple p-type diamond Hall sensors were fabricated using four silver electrodes adhered on the diamond film. The ohmic of the electrodes were confirmed by the measurement of electrical properties of electrodes and magnetic field response at three different diamond thicknesses. The response sensitivity to magnetic field were 12, 9 and 6 µV/Gauss, respectively. When the thickness of the p-type diamond Hall sensor increased, the response sensitivity to magnetic field decreased.

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