Amount Of Tar Research Articles

Analytical evaluation of the performance of pyrolysis-gasification (Py-Gs) combination within hybrid thermochemical-biological biorefinery

Thermochemical treatments like pyrolysis and gasification, were proposed to circumvent hydrolysis bottleneck of conventional 2nd generation biorefineries. Within this big-picture, the target of this article was to establish the type and amount of bioavailable matter that can be obtained through intermediate pyrolysis of biomass followed by gasification of biochar. To establish the amount of “chemical energy” partitioned among different products’ chemical oxygen demand (COD), which is proportional to higher heating value (HHV) and often utilized for biological systems, was applied for the evaluation of thermochemical conversion of a lignocellulosic feedstock (fir wood). The most abundant product of intermediate pyrolysis was biochar, which retains from 33 % to 40 % of feedstock COD (with temperatures starting from 450 °C). The yield of water-soluble pyrolysis products (WS) slightly increases from 24 % at 450 °C to 27 % at 650 °C, whereas the yield of WI increases considerably with the same temperature. Pyrolysis temperature showed a minor effect on the composition of WS as revealed by GC-MS analysis of main compounds and size exclusion chromatography. Preliminary gasification experiments, performed at 850 °C under CO2 atmosphere, provided gasification rates for different biochars, which was equal to 0.004, 0.005, 0.006 min−1 for biochars obtained at 650, 550, and 450 °C respectively. Syngas obtained from gasification of 450 °C and 550 °C biochar was almost tar-free, whereas gasification of 650 °C biochar yielded a detectable amount of tars (0.4 %). Increasing the gasification temperature to 950 °C sharply increases the gasification rate of biochar obtained at 450 °C, allowing to obtain 55% conversion yield. Within the scope of hybrid thermochemical-biological (HTB) processes, the obtained results show that intermediate pyrolysis, when coupled with subsequent 950 °C CO2 gasification of biochar, can deliver 64% of chemical energy (by COD basis) of the lignocellulosic feedstock as bioavailable constituents, which are defined to syngas and WS based on recent biological studies. Whereas downstream fermentation can process syngas and WS materials in an effective way, such yields could surpass the holocellulose-targeted methods based on hydrolysis.

Experimental investigation of the influence of calcium oxide on product quality, tar cracking efficiency, heating value, and syngas ratio in two-stage fixed bed gasification

ABSTRACT Biomass gasification is a thermochemical process used to generate hydrogen and methane for energy applications. This experimental study compares the products formed from sugarcane bagasse, bamboo, and rice-straw and evaluates the calorific value of the gas and the efficiency of homogeneous cracking in a novel, two-stage, downdraft, fixed-bed reactor. The formation of tar and the presence of carbon oxides (COx) in the gaseous product are some of the major problems with biomass gasification. In order to solve these issues, calcium oxide (CaO) is introduced with the feed in a 1:1 mass ratio as a CO2 sorbent, and its effect on the amount of tar is studied across the chosen biomasses. Experiments are conducted with the pyrolysis stage at 773 K and the air-gasification stage at 1073 K. The tar cracking efficiency of 97% is obtained with CaO for all biomasses. Rice-straw showed the highest syngas ratio of 1.83 and the volume of hydrogen increased by 13% after the addition of CaO, while bamboo had a 16% rise in hydrogen and showed the highest LHV of 12.21 MJ/m3, followed by bagasse with an LHV of 11.50 MJ/m3. The gasification efficiency for bamboo is the highest overall for both the processes.

Experimental study of biomass waste gasification: Impact of atmosphere and catalysts presence on quality of syngas production

The presented research results the gasification process of biomass waste (brewery spend grain, wheat straw, hay, pine sawdust). Experimental investigations focused on determining the influence of gasification agent (CO2, steam, and steam and CO2 mixture) and the presence of a solid catalyst (MgO∙CaO, TiO2, CuO and SrO). Investigations were performed towards syngas production. A wide range of analyses and instrumental methods were used to determine the properties of gasification process products, including: GC, TGA, FTIR, SEM, BET. The main component of syngas obtained produced in atmosphere CO2 and steam mixture was hydrogen. The H2 concentration increased from 20% up to 44% in case of brewery spend grain. The presence of the catalyst in the gasification process favoured the tar cracking reaction. The amount of tar was reduced by more than 17% in case of brewery spend grain. As well as syngas composition was enriched with CH4, H2 and CO concentration.

Darkness color index analysis using android-based RGB colorimeter for educational science purposes

The UNESCO outlined eight essential competencies that crucial for students to attain the 21st demands. Engaging science learning activities through the experimental practicum can empowers students to employ critical, active, and collaborative thinking when addressing scientific challenges, particularly those related to environmental pollution. The objective of this study how does the effect of TAR amount towards darkness color index using RGB colorimeter application. The research methodology in this study is science practicum development. In this study, science practicum activities are combined with STEM and Project-Based Learning model in conducting the activities. After conducting the experiment, the result shows that the quality of color residue is depend on the amount of TAR and Nicotine inside tobaccos. More amount of TAR in Tobaccos is Darker the color of residue. Furthermore, there are lots of variables that we should consider in this experiment. For example, duration of tobacco smoking (time), the volume of water inside the plastic bottle (volume), and the length of tobaccos (length). Because the variables can affect the tobacco residue and affect the RGB color index.

Evaluation of the influence of the fuel fines content on the stratified downdraft gasification of wood chips

Downdraft gasifiers are known to be sensitive to the fines content of the used fuel, which is why commercially available gasifiers typically require fuel with less than 5 m% fines content. Therefore, thoroughly sieved fuels are necessary, which increases the fuel costs. Despite being one main limitation of downdraft gasification, there is hardly any research investigating the impact of the fuel fines content in this process. Therefore, the aim of this work was to systematically analyze the effects of the fuel fines content on the gasification process and the gas quality. This work evaluated 34 operating points with 0 m% to 28.5 m% fuel fines content in an 85–kW stratified downdraft gasifier, with a detailed monitoring of the gasifier bed temperatures and the gas quality. The results revealed three main novelties: (1) Contrary to expectations, an increase of the fuel fines content up to 27.1 m% did not affect the temperature profile and the process stability. However, more grate shaking was required. (2) The increasing fuel fines content significantly reduced the H2 concentration in the product gas, and increased the amounts of CH4 and tars. Hence, an increase of the fuel fines worsened the gas quality. (3) The operation with 28.5 m% fines content was not able anymore, due to massive fluctuations in the gas quality. Summing up, the results of this work open the door for process optimizations of real commercial small-scale stratified downdraft gasifiers towards enhanced fuel fines tolerance.

An Analytical Study to Evaluate the Safety of Prayogika Dhumapana in Dinacharya

ABSTRACT Background: Cigarette smoking is one of the most widespread types of tobacco use all over the world, causing a huge number of untimely deaths. On contrary to cigarette smoking, dhumapana (herbal smoke inhalation) is one of the very unique routes of drug administration described by the ancient Acharyas. Aims and Objectives: The purpose of medicated dhumapana described in Ayurvedic treatises is prevention or management of vata-kapha disorders. Prayogika dhumapana is advised to be practiced regularly for health promotion and protection of our body. The present study was carried out to prepare prayogika dhumavarti (herbal cigarette) and explore the safety of prayogika dhumapana, by analyzing and comparing the chemical composition of its smoke to that of tobacco smoke. Materials and Method: Prayogika dhumavarti was prepared as per the classical text, with contents of eladi gana mentioned in Sushruta Samhita. Analytical tests were performed for various parameters, e.g. tar, nicotine, and polynuclear aromatic hydrocarbons for herbal as well as nonherbal cigarette. Results: The amount of tar in prayogika dhumavarti (herbal cigarette) was eight times lesser than the tobacco cigarette (nonherbal sample). The amount of carbon monoxide was found to be 4.0 ppm and 9.0 ppm, respectively; the amount of carbon dioxide was found to be 2281 ppm and 2702 ppm, respectively, in herbal and nonherbal samples. Conclusion: Hence, on laboratory analysis, prayogika dhumapana was found to be safe on some major parameters.

Design of Pyrolysis Plant for Waste Methyl Ethyl Ketone from the Polarizer Manufacturing Process

The rapid growth of the semiconductor industry has made significant strides in addressing clean energy concerns. However, there are still unresolved issues related to waste solvents. One promising approach to tackle these challenges is through pyrolysis. This study selected waste methyl ethyl ketone (MEK) from the industrial sector as the feedstock for pyrolysis, resulting in various residual products such as fixed carbon (char), carbon soot, and fuel gases. Experimental results demonstrated that operating temperatures between 750 and 900 °C under anaerobic conditions yielded 5% to 10 wt% of fixed carbon, along with a small amount of tar and 80% to 90% of fuel gases. The research included lab-scale pilot experiments and field-scale system studies to develop a comprehensive concept for a thermal cracking plant. SolidWorks and Aspen Plus software were applied for calculations involving heat-transfer coefficients, residence time, and the utilization of fuel gases with a boiler or burner. A field system was constructed to scale up the pyrolysis process and effectively eliminate waste solvents, incorporating an automated procedural process.

Sewage sludge and digestate gasification in an atmospheric fluidized bed gasifier

The gasification of sewage sludge (SS) and digestate was investigated in a pilot-scale fluidized bed gasifier with an output of 100 kWt. The treatment of these by-products is an ongoing challenge for sustainable development. SS and digestate are most commonly used as fertilizers. However, regulations restrict their use, mainly because of the content of heavy metals, pathogens and bacteria. Gasification of these by-products instead of application to agricultural land seems to be more efficient, as the syngas can subsequently be used for combined heat and power (CHP) generation. A series of measurements were carried out to get a better understanding of the gasification process of these fuels and to study the effects of gasifying agent on the syngas composition, particulate matter (PM) and tar. The produced syngas and tar were analyzed using a gas chromatograph with mass spectrometry (GC–MS). The results showed that no ash slagging was observed and therefore it is feasible to operate digestate and SS gasification at 750°C. The lower heating value (LHV) of the syngas from digestate and SS with air as the gasifying agent is comparable, 4.06 MJ·Nm−3 for digestate and 4.11 MJ·Nm−3 for SS. The addition of steam had a positive effect on the amount of tar and the tar dew point, which was below 150°C. Tar reduction in digestate was 5037.3 mg·Nm−3 to 3566.3 mg·Nm−3 and in SS 7447.7 mg·Nm−3 to 3390.3 mg·Nm−3. Furthermore, the concentrations of the individual tar compounds were determined and subsequently divided into tar classes.

Method for the determination of tar produced from the pyrolysis of used tires

The main issue associated with the disposal of old tires is that they contain harmful chemicals and heavy metals that can contaminate the environment as they break down. One solution to this problem is the use of a process known as pyrolysis, which breaks down the tires and produces useful by-products. This process results in the formation of gas, liquid, and solid phases, with the gas containing tar and other components. A method known as solid-phase adsorption (SPA) is here being studied as a way of determining the concentration of tar compounds. A specific sampling device using an amino-phase sorbent and activated coconut charcoal was found to be effective for collecting the tar and its volatile organic compounds from the gas produced during tire pyrolysis. The study was conducted using a double-layered pyrolysis reactor in Latvia. The amount of tar was measured by drawing varying volumes of pyrolytic gas through the adsorbents and comparing it to the amounts of individual component compounds.

Simulation of Biomass Air Gasification in a Bubbling Fluidized Bed Using Aspen Plus: A Comprehensive Model Including Tar Production.

This work studied a multistage gasification system that is designed for producing a syngas with a low tar content. The proposed system is an atmospheric bubbling fluidized-bed gasifier and comprises mainly pyrolysis, combustion, and gasification zones. The numerical investigation is performed using Aspen Plus to study Prosopis Juliflora gasification. Chemical reactions as well as tar treatment in the process are investigated. Two different pyrolysis temperatures were considered: 500 and 600 °C, along with three different particle size ranges: 0.2–0.5, 0.5–1, and 1–2 mm. The effect of the air-to-biomass ratio, with values from 0.2 to 1.2, and the gasification reactor temperature, from 800 to 1000 °C, on the composition of product gas and tar species formation during the process (phenol, naphthalene, benzene, and toluene), its lower heating value (LHV), and cold gasification efficiency (CGE) were studied. Results showed that a pyrolysis temperature of 600 °C and a particle size range of 0.2–0.5 mm displayed less tar produced from both combustion and gasification zones and were associated with greater CO, H2, and CH4 yields, compared to the other pyrolysis parameters tested. Increasing the gasification temperature led to increasing the CO, H2, and tar yields and decreasing the CH4 yield and CGE. The maximum CGE combined with the minimum tar amount produced could be obtained with values of 800 °C and 1.2 for the gasification temperature and the air-to-biomass ratio, respectively. The numerical simulation results will be used to improve the performance of the proposed system.

Kinetic modelling of pyrolysis of cellulose using CPD model: effect of salt

In this work, effect of salt on cellulose pyrolysis behaviour using chemical percolation devolatilization (CPD) model has been investigated. The distributed activation energy model (DAEM) has been used to determine the kinetics of pure and NaCl-loaded cellulose pyrolysis in a thermogravimetric analyser (TGA). A number of these experiments were performed for a range of heating rates (5–100 °C min−1) and for different concentrations of NaCl in cellulose (0.25–2 mass/%) which showed a pronounced effect of salt on the primary pyrolysis reactions of cellulose. These data were then used in a two-component DAEM to calculate the kinetic parameters for the chemical percolation devolatilization model (CPD) for both pure and NaCl-loaded cellulose. The optimized kinetic parameters for the pure and NaCl-loaded cellulose were used in the CPD model, and the product yield was predicted. The CPD predictions showed that the fraction of gases and char in the pyrolysis products increased in the presence of salt. The amount of char for pure cellulose was 6.97% which increased to 16.4% in the presence of 0.25% NaCl. The amount of gases produced as a result of pure cellulose pyrolysis was 9.63% and this amount increased with addition of NaCl to 22.85% and then further increases with an increase in NaCl concentration. Amount of tar produced for pure cellulose was 83.4%, and this amount reduced to 60.7% with addition of 0.25% NaCl. The presence of NaCl accelerates cellulose decomposition and favours the formation of gases and char.

A novel system of biomass for the generation of inherently separated syngas by combining chemical looping CO2-gasification and steam reforming process

The utilization of biomass and CO2 has become very important for solving environmental problems all over the world. In this study, a novel Fe-based CO2-gasification (FCG) process of biomass which combining chemical looping CO2 gasification and steam reforming process is proposed. The effects of experimental parameters including biomass/oxygen carrier (B/OC) ratio and initial CO2 concentration on the performance of the gas, liquid and solid products were analyzed in detail. The results show that CO2 has an opposite effect on the oxygen transfer capacity (OTC) of OC and carbon conversion rate, which results in an inflection point of initial CO2 concentration at around 20%: larger than this value, only a little hydrogen is generated, and once the concentration lower than this value, the yield of hydrogen dramatically increases. Moreover, the carbon conversion rate encountered a slight decline at the inflection point. As for the generation of tar, CO2 and OC have a synergetic effect on tar cracking: CO2 promotes the cracking of heavy tar and OC reduces the production of light tar effectively, and thus a better effect of tar cracking can be obtained when both OC and CO2 exist. This process can generate inherently separated syngas (CO-rich gas and high purity of H2), reduce the amount of undesired tar, utilize CO2 and Fe-containing solid waste, and thus this process is expected to have an extensive prospect for industrial application.

Sorption-enhanced gasification (SEG) of agroforestry residues: Influence of feedstock and main operating variables on product gas quality

Sorption-enhanced gasification (SEG) is a promising route for the conversion of biomass into synthetic fuels. There are important aspects regarding syngas quality (e.g. tar composition and/or gaseous contaminants such as H2S) that may influence the scaling-up of the process and should be assessed. Experiments were performed in a 30 kWth bubbling fluidised gasifier to evaluate the effect of the feedstock used, temperature, sorbent-to-biomass (S/B) ratio and/or steam excess on such quality aspects. Larger amounts of tars were found for straw, which corresponded to highly stable tars (benzene, toluene, naphthalene and phenanthrene). Temperature, S/B ratio and steam excess favoured tar decomposition, causing the contribution of PAHs to total tar to increase. PAHs and phenol contents were found to be related to and dependant on the temperature and S/B ratio. Elutriated CaO particles reacted with the H2S formed until equilibrium conditions were reached, leading to syngas H2S contents of between 15 and 85 ppm. Sulphur in the syngas represented no more than 15% of the total sulphur introduced into the reactor, whereas 65–85% ended up as CaS with the partially converted sorbent particles leaving the reactor.

Experimental and thermodynamic study on sorption-enhanced steam reforming of toluene for H2 production using the mixture of Ni/perovskite-CaO

It is known that a considerable amount of tar is usually generated in the biomass gasification process, and catalytic steam reforming is an effective method to remove this by-product. The coupling of in-situ CO2 capture in the process can further shift the forward reforming reaction and produce hydrogen with a high purity. In this work, sorption enhanced steam reforming (SESR) of toluene (as a model compound of biomass tar) was investigated thermodynamically and experimentally using the mechanically mixed Ni/perovskite catalyst and CaO sorbent. It is verified that the appropriate temperature is 650 °C under stoichiometric reaction (S/C = 2), and around 75% average H2 yield with a maximum H2 purity over 95% could be obtained. Moreover, the cyclic SESR-regeneration and characterization including XRD, SEM/EDS, TEM and XPS were carried out, and it shows a stable catalytic performance and compatibility of the Ni/perovskite catalyst in the SESR process for high-purity hydrogen production.

Thermodynamic analysis of an improved integrated biomass gasifier solid oxide fuel cell micro combined heat and power system

Limited overall efficiency and excessive complexity can hinder the competitiveness of biomass gasifier solid oxide fuel cell micro combined heat and power systems. To overcome these problems, hydrocarbons direct internal reforming is analysed as a strategy to increase efficiency and reduce system complexity. To the same end, two biosyngas heating-up strategies are compared: catalytic partial oxidation and afterburner off gases utilization. A comprehensive approach combining thermodynamic equilibrium calculations, experimental measurements, and system modelling was used. The gas cleaning unit should operate at 400 °C to decrease H2S and HCl below 1 ppmv. A tar amount of 120–130 g Nm−3 dry biosyngas for woodchips and 190 g Nm−3 for straw pellets was measured and 2-methoxyphenol, hydroxyacetic acid and hydroxyacetone were selected as representative compounds. With direct internal reforming the cathode air flow rate decreases from approximately 90 kg h−1 to 60 kg h−1. This leads to an increase of around 1% point in electrical efficiency and of even 5–6% points in thermal efficiency. Direct internal tar reforming seems therefore an advantageous strategy. The catalytic partial oxidation unit increases the system overall efficiency but reduces the electric efficiency from roughly 38%–30% and is therefore not advised.

Numerical Simulation of Downdraft Biomass Gasifier With Computational Fluid Dynamic

World energy demand has resulted in a surge in renewable energy needs. One of them is biomass. The gasification process takes place in a reactor called a gasifier, and the most effective way is to implement the Fixed Bed method on the downdraft gasifier. The process was executed in a downdraft gasifier because of the gas-making process without stopping the ignition and producing a small amount of tar. The biomass raw material used in this study is wood pellets because of their abundant availability in Indonesia. This research discussed numerical simulations for downdraft gasifier by utilizing wood pellet biomass as a raw material. The simulation technique is computational fluid dynamic with the DPM (Discrete Phase Model) because it can predict the experiment result details more precisely. The simulation results have shown that the convergence rate got better with the longer process iteration time. The simulation results were close to 100% in real-scale laboratory research results.

Process Simulation of Inverted Downdraft Gasifier for Tar Reduction Using in Situ Process

Biomass gasification is a topic that is currently popular technology which convert biomass to another form of energy. Unfortunately, gasification has many challenges specially to reduce tar in significant amounts which will be discussed in this journal. Regular updraft gasifier can produce 10%-30% volatile tar while many gasifiers produce so much tar that gas cleaning cost is more than the actual gasifier. In-situ method is used for reducing tar amount inside the reactor. One of the solutions is inverted downdraft gasifier implementation, which typically produces much less tar, about 1-5%. In this research, the inverted downdraft gasification was simulated by Aspen Plus which provides an overview optimal condition for less tar syngas. The result gives us highest value of syngas, 6,05 MJ/Nm3 for Coal and 6,24 MJ/Nm3 for MSW(Municipal Solid Waste) which both of them have ER 0,20. In Aspen Plus, we can discover several main parameters that can be done by finding both mass flow rate and contents in syngas which contains CH 4, H 2, CO, CO 2, O 2, H 2 S, N 2 and H 2 O.

PROSES PEMBERSIHAN SYNGAS HASIL GASIFIKASI TEMPURUNG KEMIRI MENGGUNAKAN SIKLON

This study aims to examine the process of cleaning for synthesis gas (syngas) resulted from candlenut shell gasification by using a cyclone. Research was started by design or manufacture a cyclone as a tool that can condense the tar carried in the syngas produced from the gasification process. This tool was tested with by trial and error such that got a tool that can function optimally to condense tar. The syngas cleaning experiment using the cyclone was conducted by four treatments, namely S1 (1 cyclone), S2 (2 cyclones), S3 (3 cyclones), and S4 (4 cyclones). All treatments were repeated 4 (four) times, so there were 16 experimental units. The parameter measured is the amount of tar that was condensed on the cyclone. Result showed that the syngas cleaning process using a cyclone worked well, and the best treatment was S3 (3 cyclones) with an average amount of condensed tar of 141.7 ml/kg of shell. The use of cyclones can condense tar and other particulates carried in the syngas. The cleaned syngas can be applied as fuel in an internal combustion engine as a substitute for diesel and gasoline fuels. Keywords: gasification, syngas, cleaning, cyclone

Vapor-phase hydrodeoxygenation of lignin-derived bio-oil over Al-MCM-41 supported Pd-Co and Pd-Fe catalysts

Fast pyrolysis of lignocellulosic biomass is an attractive process to produce bio-oil as an alternative liquid fuel source. Upgrading of bio-oil via hydrodeoxygenation (HDO) is an important route to accomplish this renewable energy production process. Al-MCM-41 supported Pd, Co and Fe catalysts were evaluated for HDO of guaiacol and lignin-derived bio-oil at atmospheric pressure in a fixed-bed reactor. Bimetallic Pd-Co and Pd-Fe catalysts showed higher HDO yield and stability than the monometallic Co and Fe catalysts. The addition of Pd significantly enhanced the stability of Co and Fe catalysts since it helped reduce the coke formation. The lignin-derived bio-oil mainly contained phenolic compounds which had one to three oxygen atoms. The catalytic upgrading could not only eliminate significantly the oxygen of these phenolic compounds but also reduce the amount of tar and heavy components. Pd-Fe catalyst was recognized as a suitable catalyst for upgrading of lignin-derived bio-oil since it produced more deoxygenated products and less gas-phase yield than Pd-Co catalyst.

Evaluation of devolatilization behaviour of different carbonaceous materials under rapid heating for the novel HIsarna ironmaking process

A drop-tube furnace coupled with quadrupole mass spectrometer (DTF-QMS) was employed to simulate rapid heating conditions that carbonaceous materials experience during HIsarna injection with the measurement of gas composition change as a result. A devolatilization study for thermal coal (TC) and charcoal (CC) samples was carried out at three temperatures of 1000, 1250 and 1500 °C under an initial high purity Ar gas environment. The volatiles released were measured online by QMS, while the char yield was determined directly by the weight of particles collected and the deficit was calculated by subtracting the gas yielded from the total weight loss. The study reveals that working temperature has a strong impact on the devolatilization rate, the maximum weight loss and the variation in gas species produced. Due to intensification in the carbon oxidation and secondary reactions at higher temperatures, there was an increase in the weight loss, which led to a greater yield of H2 and CO but less yield of hydrocarbons, CO2 and H2O. Despite lower volatile matter content in charcoal, the weight loss for charcoal (29%) was higher than that for thermal coal (23%) at 1500 °C. Although the amount of H2 produced for both materials is similar, the amount of CO produced by charcoal is twice of that by thermal coal, and accounts for 79% of the total gas weight formed by charcoal. This suggests that a higher rate of carbon oxidation takes place through O2 containing groups within the charcoal, which results in lower char efficiency. It was found that thermal coal produces a significant amount of tar, while a large number of particles in the form of soot/dust escaped from the bulk material during charcoal injection but no tar formation was observed.