Thermobalance Reactor Research Articles

A comprehensive study on by-products of food processing industry pyrolysis using a thermobalance reactor coupled to GC-FID/TCD: Mass, atomic and energy balances, thermokinetic modeling, product distribution, and characterization

The current study aims to investigate the pyrolysis process and bioenergetic potential of pineapple peel and passion fruit shell wastes (by-products of food processing industry) by the physicochemical characterization, mass balance, energy balance, atomic balance, and kinetic study. Pyrolysis was performed at low heating rates (5, 10, and 15 °C min−1) in an argon atmosphere in a thermobalance reactor coupled to GC-FID/TCD. The pyrolysis showed a higher yield of non-condensable gases that had low calorific value (<3.51 MJ kg−1gas) due to the high concentration of CO2, which are from oxygenated functional groups. The fraction of solid and liquid had calorific value greater than 26.84 MJ kg−1, where biochar is favorable for application in steam gasification due the ash composition. For the energy balance, it was observed that the pyrolysis condition in the current study provided little exothermic characteristics for global process of both biomasses. Thermogravimetric data showed two main regions of pyrolysis (active pyrolysis and passive pyrolysis). The high release of CO and CO2 with high weight loss rate were observed in active pyrolysis (<370 °C), while the release of CH4 and H2 with low weight loss rate were observed in passive pyrolysis (>370 °C). For the kinetic study, it was assumed the presence of four pseudo-components, which were extracted from thermogravimetric data using the deconvolution tool. The kinetic parameters obtained from the Vyazovkin method, compensation effect, and mater plot could satisfactorily describe the pyrolysis process of both biomasses, with a determination coefficient greater than 0.9.

Different combustion modes and flame shapes in massive loads of polyethylene revealed by macro-thermogravimetry

While thermogravimetric analysis can reveal the reaction mechanisms that occur during combustions, it cannot be used to study reactions involving large fuel loads. A large capacity thermobalance reactor is thus required to reveal thermal events that can have a substantial effect on reaction rates. The study presented in this article highlights the value of using macro-thermogravimetry to study the combustion of large loads of polyethylene, a representative thermoplastic polymer. A coupled analysis of mass loss and the corresponding heat flows reveals three distinct combustion regimes, which differ by the shape and position of the flame, which either remains above or, transiently or continuously, wraps around the load. In the first case, radiation from the flame only affects the upper surface of the load and has little effect on the combustion rate. In the second case, the integrated effect of this radiation on part of the outer surface of the crucible substantially accelerates the process, which eventually slows as the flame relocates above the charge. The third regime occurs for large loads, when the filling factor of the reactor is high. The radiation affects the entire external surface of the load, leading to very high combustion rates until the polymer is completely consumed. Simulations of the combustion process support the conclusions derived from experimental data. These results should prove valuable for the development of robust and effective techniques to destroy dangerous organic materials.

Pyrolysis characteristics of Kazakhstan coals in non-isothermal and isothermal conditions

ABSTRACT This study provides combined isothermal and non-isothermal pyrolysis properties of Kazakhstan coals necessary for development and optimization of thermal processes. Devolatilization properties are investigated using thermogravimetric analysis, thermobalance reactor, and wire-mesh reactor experiments at temperatures from 400°C to 1,000°C. Maikuben coal has the highest reactivity at 900°C and Shubarkol coal has lowest ash initial deformation. Turgay coal demonstrates high gas yield at 800°C and above. At temperatures above 800°C tar cracking intensifies, but tar release from Shubarkol coal increased reaching 8.06% of initial mass at 1,000°C. Results demonstrate that Shubarkol and Turgay coals are favorable gasification feedstock.

Investigation of the Reaction Behavior of Albizia gummifera Wood under Steam Gasification with Varied Partial Pressures and Gasification Temperatures

The astronomical increase in global energy demand makes locating energy sources other than fossil fuels worthwhile. The use of tropical biomass wood waste as a renewable energy source was investigated in this study. The thermal conversion analysis of Albizia gummifera (ayinre) was carried out in a thermobalance reactor via steam gasification under varying temperature (700 to 1000 °C) and steam partial pressure (0.020 to 0.050 MPa). The experimental data was evaluated using three gas-solid reaction models. The modified volume reaction model (mVRM) gave the overall highest coefficient of determination (0.9993) and thereby the best conversion prediction. The observed char activation constant rates (from paired reaction conditions) indicated, on average, an increase in reactivity as the parameters increased. The results showed that the activation energy of the mVRM gave the lowest value (32.54 kJ/mol) compared with those of the shrinking core model (SCM) and the volume reaction model (VRM) (49.29 and 49.89 kJ/mol, respectively).

하수슬러지 가스화의 kinetics 및 합성가스 생산 연구

Gasification characteristics and gas produced from a sewage sludge char were analyzed by using a thermobalance reactor, which is used for a reaction kinetic analysis by measuring weight change of materials at a desired temperature. Gasification reaction rate increased with increasing temperature and steam partial pressure due to the promotion of gasification reaction. Three models of gas-solid reaction were applied to the reaction kinetics analysis and modified volumetric reaction model was an appropriated model for the steam gasification of the sewage sludge char. Apparent activation energy and pre-exponential factors were evaluated as 155.5 kJ/mol and , respectively. The order of reaction on steam partial pressure was 0.68. Gas analysis was performed at and hydrogen concentration was highest in the gas concentrations, which increased with increasing the steam partial pressure. Hydrogen concentration increased the most and hydrogen concentration in the produced gas was 2-4 times higher than that of carbon monoxide due to the gasification and water gas shift reaction.

순산소 가스화 반응장에서 CO&lt;sub&gt;2&lt;/sub&gt; 전환 메커니즘 연구

Oxy gasification was performed for the production of high quality syngas from the waste. was used as reactant with for gasification and greenhouse gas reduction. Therefore, gasification was performed at high temperature of . RPF was gasified in the thermobalance and 0.5 ton/day pilot plant gasifier. Weight variation with temperature and CO production by Boudouard reaction were studied for gasification of RPF in thermobalance reactor. Syngas of high concentration was produced from oxy gasification in 0.5 ton/day pilot system, which showed appropriate /CO ratio for the production of transport fuel and chemical products.

Pyrolysis characteristics of glass fiber-reinforced plastic (GFRP) under isothermal conditions

The pyrolysis characteristics of GFRP (glass fiber reinforced plastic) were determined under isothermal conditions at 500–1000°C using a thermo-balance reactor (TBR) and wire mesh reactor (WMR). The kinetics parameters for the GFRP were derived using the activation energy, of 28.17kJmol−1, of frequency factor, 2.12s−1, and reaction order, of 0.48–0.8. The structural variations in the GFRP char were determined using BET, SEM, and FT-IR techniques. Organic compounds and polymers were decomposed with increasing temperature. The experimental results showed that increasing the temperature and reaction time favored polymer scission at temperature of 600–1000°C with residence time of 2–10s.

하수 슬러지의 열분해 및 연소 Kinetics 연구

Effective treatment and energy conversion technologies are necessary due to the ban of the dumping of organic waste including the sewage sludge. In this study, the kinetics of pyrolysis and combustion were derived in a TGA and thermobalance reactor, which is essential for thermal conversion of sewage sludge to energy. Three steps are shown for the pyrolysis in TGA and the different pre-exponential factors and activation energies are derived depending on the temperature range. Three models of gassolid reaction were applied to the reaction kinetics analysis for the combustion of sewage sludge char and shrinking core model was an appropriated model. Apparent activation energy and pre-exponential factor were evaluated and the effect of oxygen partial pressure was examined.

톱밥 촤의 고온 수증기 가스화 특성

Steam gasification of sawdust char was performed in a thermobalance reactor at high temperature. Gasification temperature was changed from to and steam partial pressure was 0.3, 0.5 and 0.7 atm. Three models of gas-solid reaction were applied to the reaction kinetics analysis and modified volumetric model was an appropriate model. Reaction control regime and diffusion control regime were distinct depending on the temperature. Apparent activation energy and pre-exponential factors for both of the regimes were evaluated and the effects of steam partial pressure were examined. concentration in the produced gas was two times higher than that of CO due to the gasification accompanying by the water gas shift reaction.

Pyrolysis kinetics of coking coal mixed with biomass under non-isothermal and isothermal conditions

To investigate the kinetic characteristics of coking coal mixed with biomass during pyrolysis, thermogravimetric (TG) and thermo-balance reactor (TBR) analyses were conducted under non-isothermal and isothermal condition. Yellow poplar as a biomass (B) was mixed with weak coking coal (WC) and hard coking coal (HC), respectively. The calculated activation energies of WC/B blends were higher than those of HC/B blends under non-isothermal and isothermal conditions. The coal/biomass blends show increased reactivity and decreased activation energy with increasing biomass blend ratio, regardless of the coking properties of the coal. The different char structures of the WC/B and HC/B blends were analyzed by BET and SEM.

Influences of heating rate during coal char preparation and AAEMs on volatile–char interaction with different sources of biomass volatile

Volatile–char interaction is important for the operation of co-gasification of coal and biomass. Biomass generally produces large amount of volatiles while char is mainly produced from coal. Hence, in this study, the interaction between coal char and volatiles from biomass samples (xylan, cellulose and rice straw) was examined using a rapid-heating thermobalance reactor. Three types of coal char, consisting of slow pyrolyzed-coal char (Ex-char), fast pyrolyzed-coal char (In-char), and acid washed-coal char (Ac-char), were employed to reveal influences of heating rate during char preparation and retention of alkali and alkaline earth metallic (AAEM) species on char surface. The steam gasification rates of all coal chars in both cases with and without volatile contacting were investigated from the gas evolution rate and remaining char analyses. The results indicate that the steam gasification rates of Ex-char and In-char were significantly diminished by the volatiles derived from all sources, especially rice straw. However, in the case of Ac-char, the reduction of steam gasification rate was less important. Moreover, the Ex-char exhibited the catalyst for the decomposition of biomass volatiles, resulting in the increase in gas production rate. Porous structure and the AAEM over char play crucial roles on the volatile–char interaction.

나무칩, 톱밥 바이오매스와 갈탄의 수증기 가스화반응 특성 연구

바이오매스 및 저등급 석탄인 갈탄은 잠재력이 큰 에너지원으로 이들을 가스화하여 합성가스를 얻으면 발전을 하거나 수송용 연료를 생산할 수 있다. 본 연구에서는 상압의 열천칭 반응기(thermobalance)에서 woodchip, 톱밥, 갈탄의 수증기 가스화반응의 kinetics를 조사하였다. 가스화 온도 <TEX>$600{\sim}900^{\circ}C$</TEX>, 수증기 분압 20~90 kPa 범위에서 수증기 가스화 반응을 수행하였다. 세 가지의 기체-고체 화학반응모델들이 가스화반응의 거동을 묘사하는 능력을 비교하였다. 이들 중에서 탄소전환율의 변화를 가장 잘 나타내는 modified volumetric model을 사용하여 가스화반응의 kinetic 정보를 도출하였다. Arrehenius plot으로부터 얻어진 시료들의 활성화에너지는 문헌상의 범위 내에서 얻어졌으며 톱밥 > woodchip > 갈탄의 순으로 나타났다. 각 시료에 대하여 수증기 분압에 대한 반응차수를 결정하였으며, 가스화공정 설계의 기초 데이터로서 겉보기 반응속도식을 제시하였다. Biomass and low-grade coals are known to be better potential sources of energy compared to crude oil and natural gas since these materials are readily available and found to have large reserves, respectively. Gasification of these carbonaceous materials produced syngas for chemical synthesis and power generation. Woodchip, sawdust and lignite were gasified with steam in a thermobalance reactor under atmospheric pressure in order to evaluate their kinetic rate information. The effects of gasification temperature (<TEX>$600{\sim}900^{\circ}C$</TEX>) and partial pressure of steam (20~90 kPa) on the gasification rate were investigated. The three different types of gas-solid reaction models were applied to the experimental data to predict the behavior of the gasification reactions. The modified volumetric model predicted the conversion data well, thus the model was used to evaluate kinetic parameters in this study. The observed activation energy of biomass, sawdust and lignite gasification reactions were found to be in reasonable range and their rank was found to be sawdust > woodchip > lignite. The expression of apparent reaction rates for steam gasification of the three solids was proposed to provide basic information on the design of coal gasification processes.

Synergetic effect during co-pyrolysis/gasification of biomass and sub-bituminous coal

In this work, the co-pyrolysis of Indonesian coal (sub-bituminous) and two types of biomass, rice straw and Leucaena leucocepha wood, was studied using a drop tube fixed-bed reactor. The gasification reactivity of the obtained co-pyrolyzed char with steam was examined using a rapid heating thermobalance reactor. In the co-pyrolysis, a synergetic effect, in terms of higher gas yield and lower tar and char yields, was manifested especially at a biomass and coal ratio of 1:1. This synergetic effect could be explained by the transferring of active OH and H radicals from the biomass to the coal as well as the catalytic role of potassium (K) from the biomass. In the steam gasification, the in situ pyrolyzed char from the coal/biomass blend exhibited a higher reactivity than that from the coal or the biomass. This could be related to the increased surface area and pore volume of chars from the blend as well as the influence of volatile K released from the biomass. In addition, the biomass type appeared to have a significant influence not only on the magnitude of the synergetic effect during the co-pyrolysis but also on the reactivity of the resultant chars.

Pyrolytic characteristics of Jatropha seedshell cake in thermobalance and fluidized bed reactors

Pyrolytic kinetic parameters of Jatropha seedshell cake (JSC) were determined based on reaction mechanism approach under isothermal condition in a thermobalance reactor. Avrami-Erofeev reaction model represents the pyrolysis conversion of JSC waste well with activation energy of 36.4 kJ mol−1 and frequency factor of 9.18 s−1. The effects of reaction temperature, gas flow rate and feedstock particle size on the products distribution have been determined in a bubbling fluidized bed reactor. Pyrolytic bio-oil yield increases up to 42 wt% at 500 °C with the mean particle size of 1.7 mm and gas flow rate higher than 3U mf , where the maximum heating value of bio-oil was obtained. The pyrolytic bio-oil is characterized by more oxygen, lower HHVs, less sulfur and more nitrogen than petroleum fuel oils. The pyrolytic oil showed plateaus around 360 °C in distribution of components’ boiling point due to high yields of fatty acid and glycerides.

저급 석탄과 혼합한 폐촉매의 수증기 가스화 반응에 미치는 영향

We have investigated the kinetics and activity of waste catalysts for steam-lignite gasification. Waste catalysts I, II, III and reference <TEX>$K_2CO_3$</TEX> were used and physical mixed with a coal. The gasification experiments were carried out with the low rank coal loaded with 1 wt% and 5 wt% catalyst at the temperature range from 700 to <TEX>$900^{\circ}C$</TEX> using thermobalance reactor. It was observed that the carbon conversion reached almost 100% regardless of the kinds of catalysts at <TEX>$900^{\circ}C$</TEX>. The shortest time to reach the designated conversion was obtained for 1 wt% waste catalyst II and 5 wt% <TEX>$K_2CO_3$</TEX> at <TEX>$900^{\circ}C$</TEX>. The gasification reaction rate constant increased with increasing the temperature. Highest rate constant was obtained with <TEX>$K_2CO_3$</TEX> at <TEX>$900^{\circ}C$</TEX>. The lowest activation energy was 69.42 kJ/mol for 5 wt% waste catalyst II. The waste catalyst had an influence on the reduction of activation energy.

열천칭과 유동층반응기에서 석탄과 Petroleum Coke의 수증기 가스화반응

Lignite of low rank coal and petroleum coke of high sulfur content can be high potential energy sources for coal gasification process because of their plentiful supply. The steam gasification of lignite, anthracite, and pet coke has been carried out in both an atmospheric thermobalance reactor and a lab-scale fludized bed reactor (0.02 m i.d. 0.6 m height). The effects of gasification temperature () and partial pressure of steam (0.15~0.95 atm) on the gasification rate and on the heating value of product gas have been investigated. The modified volumetric reaction model was applied to the experimental data to describe the behavior of carbon conversion, and to evaluate kinetic parameters of char gasification. The results shows that higher temperature bring more hydrogen in the product syngas, and thus increased gas heating value. The feed rate of steam is needed to be optimized because an excess steam input would lower the gasification temperature which results in a degradation of fuel quality. The rank of calorific value of the product gas was anthracite > lignite > pet coke. Their obtained calorific value at with 95% steam feed were 10.0 > 6.9 > 5.7 . This study indicates that lignite and pet coke has a potential in fuel gas production.

볏집, 톱밥 바이오매스와 석탄의 수증기 가스화반응 Kinetics 연구

볏짚 톱밥과 같은 바이오매스는 석탄과 함께 사용할 수 있는 잠재력이 큰 에너지원으로 이들을 가스화공정에 적용하면 수송용 연료같은 bio-oil을 생산할 수 있다. 본 연구에서는 상압의 열천칭 반응기(thermobalance)에서 톱밥, 볏짚, 갈탄, 역청탄, 무연탄의 수증기 가스화 반응특성을 수행하였으며, 가스화 온도 <TEX>$600{\sim}850^{\circ}C$</TEX>, 수증기 분압 30~90 kPa의 범위에서 조업변수들이 가스화반응속도에 미치는 영향을 조사하였다. 세 가지의 기체-고체 화학반응모델이 가스화반응의 거동을 예측하는 능력을 비교하였으며, modified volumetric reaction model을 사용하여 공정설계에 필수적인 kinetic 정보를 도출하였다. 두 가지 바이오매스와 세 가지 석탄 촤의 가스화반응성을 비교하였다. Arrhenius plot으로부터 얻어진 바이오매스와 석탄의 활성화에너지는 모두 문헌상의 범위에 속하였다. 각 연료에 대하여 수증기분압에 대한 반응차수를 결정하였으며, 가스화공정 설계의 기초데이타로서 겉보기 반응속도식을 제시하였다. Biomass and coal are great potential energy sources for gasification process. These solids can be gasified to produce syngas and bio-oil which can be upgraded further to transportation fuel. Two biomass and three coals have been gasified with steam in a thermobalance reactor under atmospheric pressure in order to evaluate their kinetic rate information The effects of gasification temperature (<TEX>$600{\sim}850^{\circ}C$</TEX>) and partial pressure of steam (30~90 kPa) on the gasification rate have been investigated. The three different types of gas-solids reaction models have been applied to the experimental data to compare their predictions of reaction behavior. The modified volumetric reaction model predicts the conversion data well, thus that model was used to evaluate kinetic parameters in this study. The gasification reactivity of five solids has been compared. The obtained activation energy of coal and biomass gasification were well in the reasonable range. The expression of apparent reaction rates for steam gasification of five solids have been proposed as basic information for the design of coal gasification processes.

Inhibition of steam gasification of biomass char by hydrogen and tar

The influence of hydrogen and tar on the reaction rate of woody biomass char in steam gasification was investigated by varying the concentrations in a rapid-heating thermobalance reactor. It was observed that the steam gasification of biomass char can be separated into two periods. Compared with the first period, in the second period (in which the relative mass of remaining char is smaller than 0.4) the gasification rate is increased. These effects are probably due to inherent potassium catalyst. Higher hydrogen partial pressure greatly inhibits the gasification of biomass char in the first and second periods. By calculating the first-order rate constants of char gasification in the first and second periods, we found that the hydrogen inhibition on biomass char gasification is caused by the reverse oxygen exchange reaction in the first period. In the second period, dissociative hydrogen adsorption on the char is the major inhibition reaction. The influence of levoglucosan, a major tar component derived from cellulose, was also examined. We found that not only hydrogen but also vapor-phase levoglucosan and its pyrolysates inhibited the steam gasification of woody biomass char. By mixing levoglucosan with woody biomass sample, the pyrolysis of char proceeds slightly more rapidly than with woody biomass alone, and gas evolution rates of H2 and CO2 are larger in steam gasification.

Pyrolysis characteristics of coal and RDF blends in non-isothermal and isothermal conditions

Pyrolysis characteristics of the sub-bituminous coal, Refuse Derived Fuel (RDF) and their blends were determined at non-isothermal (15 °C/min) and isothermal (500–800 °C) conditions in thermo-gravimetric analyzer (TGA) and a thermobalance reactor. The decomposition rates of coal and RDF blends are higher than the calculated values of each fuel at the lower temperature ranges (300–385 °C). In the isothermal condition, activation energies of coal and RDF blends are lower and the pyrolysis reactivity is higher than the calculated values of each fuel. The synergistic effect exhibits remarkably with the RDF blend ratio of 50% at 700 °C. The structural variation and inorganic matters of chars from coal and RDF were determined by using BET, SEM, and XRD techniques. Surface area of the blend char increases and the average pore size decreases with pyrolysis. The addition of RDF into coal produces sulfur fixation of CaS and CaSO 3 based on the XRD data.

A simple expression for the apparent reaction rate of large wood char gasification with steam

A simple expression for the apparent reaction rate of large wood char gasification with steam is proposed. Large char samples were gasified under steam atmosphere using a thermo-balance reactor. The apparent reaction rate was expressed as the product of the intrinsic rate and the effective factor. The effective factor was modified to include the effect of change in char diameter and intrinsic reaction rate during the reaction. Assuming uniform conversion ratio throughout a particle, the simplified reaction scheme was divided into three stages. In the initial stage, the local conversion ratio increases without particle shrinkage. In the middle stage, the particle shrinks following the shrinking core model without change in the local conversion ratio. In the final stage, the local conversion ratio increases without particle shrinkage. The validity of the modified effective value was confirmed by comparison with experimental results.