scholarly journals Preparation of biochar via dry torrefaction of wood meal in a batch reactor under pressure and its co-combustion behavior with anthracite coal

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 997-1008
Author(s):  
Wei Yang ◽  
Fan Yang ◽  
Xu Zhang ◽  
Pengfei Zhu ◽  
Huanghu Peng ◽  
...  
Keyword(s):  
Activation Energy ◽  
Lower Energy ◽  
Batch Reactor ◽  
Synergetic Effect ◽  
Obvious Effect ◽  
Heating Value ◽  
Optimal Ratio ◽  
Wood Meal ◽  
Combustion Behavior ◽  
Anthracite Coal

Biochar was prepared by dry torrefaction of wood meal in a batch reactor under pressurized conditions. The biochar prepared at 340 °C (WMB-340) showed a higher heating value (HHV) of 30.5 MJ/kg, and it was employed to co-combust with anthracite coal (AC) with the HHV of 28 MJ/kg. The WMB-340 underwent two combustion stages, while the AC only showed one combustion stage. The combustion of AC was promoted by WMB-340 at temperatures higher than 490 °C, indicating the existence of a synergetic effect during co-combustion. Blending AC with 10% WMB-340 had no obvious effect on the combustion stage of AC. However, three combustion stages existed when blending more than 10% WMB-340 with AC. The activation energy of AC blended with 10% WMB-340 was 84.5 kJ mol-1, much lower than that of AC (179.3 kJ mol-1), indicating a lower energy for initialization of the blend. Therefore, AC blended with 10% WMB-340 was the optimal ratio for co-combustion in this study.

scholarly journals Hydrothermal Carbonization (HTC) of Seaweed (Macroalgae) for Producing Hydrochar

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1805
Author(s):  
Neel Patel ◽  
Bishnu Acharya ◽  
Prabir Basu
Keyword(s):  
Batch Reactor ◽  
Reaction Times ◽  
Hydrothermal Carbonization ◽  
Process Conditions ◽  
Maritime Provinces ◽  
Heating Value ◽  
Direct Combustion ◽  
Ecological Problems ◽  
Liquid Slurry ◽  
Work Done

Waste seaweed that is collected at coastal regions of maritime provinces in Canada is creating ecological problems as it promotes an anoxic event, which produces nearly zero dissolved oxygen in water along with hydrogen sulfide emission. The work done in this study attempts to address this issue by producing a coal-like solid hydrochar and nutritious liquid slurry (processed water) by employing a rather recent thermo-chemical process called hydrothermal carbonization (HTC) on the seaweed. The HTC was carried out in a batch reactor system for three different reaction temperatures, 180 °C, 200 °C, 220 °C, and three different reaction times, 30, 60, and 120 min. Each of the produced hydrochars was characterized by different analytical methods. The effects of the process conditions on the yield and the properties of the hydrochar and process water were examined. The hydrochar produced at 220 °C and 120 min showed the highest carbon content (48.5%) and heating value (18.93 MJ/kg). The energy density and carbon to nitrogen (C/N) ratio in the hydrochar increased significantly as compared to raw seaweed. Moreover, HTC reduced the ash yield and volatile compounds of the seaweed. Thus, hydrochar can be used as a fuel for direct combustion, in soil remediation, or in carbon sequestration applications.

scholarly journals Study on indium leaching from mechanically activated hard zinc residue

2011 ◽  
Vol 47 (1) ◽  
pp. 63-72 ◽  
Author(s):  
J.H. Yao ◽  
X.H. Li ◽  
Y.W. Li
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Planetary Mill ◽  
Leaching Rate ◽  
Obvious Effect ◽  
Diffusion Controlled ◽  
Leaching Reaction ◽  
Kinetics Of ◽  
Positive Effect ◽  
Solution Kinetics

In this study, changes in physicochemical properties and leachability of indium from mechanically activated hard zinc residue by planetary mill were investigated. The results showed that mechanical activation increased specific surface area, reaction activity of hard zinc residue, and decreased its particle size, which had a positive effect on indium extraction from hard zinc residue in hydrochloric acid solution. Kinetics of indium leaching from unmilled and activated hard zinc residue were also investigated, respectively. It was found that temperature had an obvious effect on indium leaching rate. Two different kinetic models corresponding to reactions which are diffusion controlled, [1-(1- x)1/3]2=kt and (1-2x/3)-(1-x)2/3=kt were used to describe the kinetics of indium leaching from unmilled sample and activated sample, respectively. Their activation energies were determined to be 17.89 kJ/mol (umilled) and 11.65 kJ/mol (activated) within the temperature range of 30?C to 90?C, which is characteristic for a diffusion controlled process. The values of activation energy demonstrated that the leaching reaction of indium became less sensitive to temperature after hard zinc residue mechanically activated by planetary mill.

Combustion Behavior and SO2, NOx Emissions of an Anthracite Coal in a Circulating Fluidized Bed

2005 ◽  
Author(s):  
Leming Cheng ◽  
Zhongyang Luo ◽  
Zhenglun Shi ◽  
Haixiao Zheng ◽  
Qinghui Wang ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Cross Section ◽  
Circulating Fluidized Bed ◽  
Nox Emissions ◽  
So2 Emission ◽  
Combustion Behavior ◽  
Excess Air ◽  
Anthracite Coal ◽  
Bed Temperature ◽  
Experimental Researches

Combustion behavior and SO2, NOx emissions of anthracite coal in a circulating fluidized bed are reported in this paper. Experimental researches were done on a 1 MWt circulating fluidized bed facility with a 0.31 m × 0.31 m cross section and 11.2 m height combustor. The anthracite coal with 6.28% volatile and 3.76% sulfur content burns steadily during the test. The bed was operated under different temperature, Ca/S ratio and excess air. A limestone containing 75% CaCO3 and 15% MgCO3 was used as the sulfur sorbent. Results show that the SO2 emission varies with operating bed temperature and more than 90% sulfur capture efficiency can be reached while Ca/S is about 3. With Rosemount Analytical NGA2000, N2O, NO and NO2 were also measured in the test. It was found the majority content of NOx was NO and the least was NO2. Those NOx emissions change highly with the excess air number.

scholarly journals Torrefaction of Sewage Sludge: Kinetics and Fuel Properties of Biochars

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 565 ◽  
Author(s):  
Jakub Pulka ◽  
Piotr Manczarski ◽  
Jacek Koziel ◽  
Andrzej Białowiec
Keyword(s):  
Activation Energy ◽  
Sewage Sludge ◽  
Thermal Transformation ◽  
Fuel Properties ◽  
Process Time ◽  
Technological Aspect ◽  
Heating Value ◽  
Valuable Product ◽  
Kinetics Of

We propose a ‘Waste to Carbon’ thermal transformation of sewage sludge (SS) via torrefaction to a valuable product (fuel) with a high content of carbon. One important, technological aspect to develop this concept is the determination of activation energy needed for torrefaction. Thus, this research aimed to evaluate the kinetics of SS torrefaction and determine the effects of process temperature on fuel properties of torrefied products (biochars). Torrefaction was performed using high ash content SS at six (200~300 °C) temperatures and 60 min residence (process) time. Mass loss during torrefaction ranged from 10~20%. The resulting activation energy for SS torrefaction was ~12.007 kJ·mol−1. Initial (unprocessed) SS higher heating value (HHV) was 13.5 MJ·kg−1. However, the increase of torrefaction temperature decreased HHV from 13.4 to 3.8 MJ·kg−1. Elemental analysis showed a significant decrease of the H/C ratio that occurred during torrefaction, while the O/C ratio fluctuated with much smaller differences. Although the activation energy was significantly lower compared with lignocellulosic materials, low-temperature SS torrefaction technology could be explored for further SS stabilization and utilization (e.g., dewatering and hygienization).

scholarly journals Experimental Analysis of Brewers’ Spent Grains Steam Gasification in an Allothermal Batch Reactor

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 912 ◽  
Author(s):  
Sérgio Ferreira ◽  
Eliseu Monteiro ◽  
Paulo Brito ◽  
Carlos Castro ◽  
Luís Calado ◽  
...  
Keyword(s):  
Batch Reactor ◽  
Steam Gasification ◽  
Effect Of Temperature ◽  
Carbon Conversion ◽  
Heating Value ◽  
Combustible Gas ◽  
Energy Needs ◽  
Rotary Dryer ◽  
Spent Grains ◽  
Conversion Efficiencies

In this work, brewers’ spent grains (BSG) were evaluated and studied in order to obtain a combustible gas by means of allothermal steam gasification. BSG were preprocessed in a rotary dryer and a pelletizer prior to gasification in an indirectly heated batch reactor. BSG characterization was conducted by means of proximate, ultimate, and thermogravimetric analysis, allowing us to conclude that BSG have characteristics comparable to those of regular lignocellulosic biomasses. Gasification tests were performed in an allothermal bench-scale batch reactor in order to determine the effect of temperature and steam-to-biomass ratio (S/B) in the produced gas. The produced gas was mainly composed of 22.8–30.2% H2, 15.1–22.3% CO, and 7.2–11.1% CH4, contributing to a heating value of 8.11–9.0 MJ/Nm3 with the higher values found for a low S/B ratio and for high temperatures. The performance of the process was assessed by evaluating the cold gas and carbon conversion efficiencies. These indicators were found to be in the ranges 47.0%–52.1% and 57.0%–62.7%, respectively. The main conclusion of this work is that the produced gas obtained from BSG steam gasification has sufficient quality to open other options to beer producers to use their own brewing wastes to satisfy their energy needs, allowing them to progress toward the circular economy concept.

scholarly journals Catalytic Hydrothermal Liquefaction of Penicillin Residue for the Production of Bio-Oil over Different Homogeneous/Heterogeneous Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 849
Author(s):  
Chen Hong ◽  
Zhiqiang Wang ◽  
Yanxiao Si ◽  
Yi Xing ◽  
Jian Yang ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Catalytic Performance ◽  
Hydrothermal Liquefaction ◽  
Oil Yield ◽  
Obvious Effect ◽  
Heating Value ◽  
Bio Oil ◽  
Cracking Reaction ◽  
Secondary Cracking ◽  
Antibiotic Fermentation

In this study, penicillin residue (PR) was used to prepare bio-oil by hydrothermal liquefaction. The effects of homogeneous (organic acid and alkaline catalysts) and heterogeneous catalysts (zeolite molecular sieve) on the yield and properties of bio-oil were investigated. The results show that there are significant differences in the catalytic performance of the catalysts. The effect of homogeneous catalysts on the bio-oil yield was not significant, which only increased from 26.09 (no catalysts) to 31.44 wt.% (Na2CO3, 8 wt.%). In contrast, heterogeneous catalysts had a more obvious effect, and the oil yield reached 36.44 wt.% after adding 5 wt.% MCM-48. Increasing the amount of catalyst enhanced the yield of bio-oil, but excessive amounts of catalyst led to a secondary cracking reaction, resulting in a reduction in bio-oil. Catalytic hydrothermal liquefaction reduced the contents of heteroatoms (oxygen, mainly), slightly increased the contents of C and H in the bio-oil and increased the higher heating value (HHV) and energy recovery (ER) of bio-oil. FTIR and GC-MS analyses showed that the addition of catalysts was beneficial in increasing hydrocarbons and oxygen-containing hydrocarbons in bio-oil and reducing the proportion of nitrogen-containing substances. Comprehensive analyses of the distribution of aromatic, nitrogen-containing and oxygen-containing components in bio-oil were also performed. This work is beneficial for further research on the preparation of bio-oil by hydrothermal liquefaction of antibiotic fermentation residue.

Thermochemical properties of energy crop species planted in Slovakia

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 764-778
Author(s):  
Andrea Majlingová ◽  
Martin Lieskovský ◽  
Milan Oravec ◽  
Marek Trenčiansky ◽  
Rastislav Veľas
Keyword(s):  
Activation Energy ◽  
Chemical Properties ◽  
Arundo Donax ◽  
Energy Crops ◽  
Energy Crop ◽  
Small Scale ◽  
Agricultural Activity ◽  
Crop Species ◽  
Heating Value ◽  
Miscanthus Giganteus

In the last decades, a new phenomenon has arisen in connection with temporary or permanent non-use of land for agricultural activity, namely the cultivation of energy crops in these localities, because of growing demand for biomass as a fuel. Farmers are expected to sell energy crops and the fuels they produce, both at home and in the surrounding countries. To choose economically efficient energy crop species to cultivate, the thermochemical parameters of the crop should be used to support decision-making process of farmers. This paper summarizes the results of small-scale laboratory tests of three energy crop species planted in Slovakia – Sida hermaphrodita, Arundo donax, and Miscanthus × giganteus – used for determination of thermal and chemical properties of the energy crop species to evaluate their suitability for energy purposes. The most suitable species for energy purposes was found to be Miscanthus × giganteus with higher heating value of 19.6 MJ/kg, lower heating value of 14.8 MJ/kg (at moisture content of 17%), and ash mass of 2.67% dry mass (d.m.). From a lignin mass and activation energy point of view, the most suitable for energy purposes was Arundo donax, with a lignin mass of 20.5% d.m. and an activation energy of 124.2 kJ/mol.

Reaction kinetics of malachite in ammonium carbamate solution

2015 ◽  
Vol 69 (9) ◽  
Author(s):  
Ying-Bo Mao ◽  
Jiu-Shuai Deng ◽  
Shu-Ming Wen ◽  
Jian-Jun Fang
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Dissolution Rate ◽  
Batch Reactor ◽  
Shrinking Core Model ◽  
Surface Chemical ◽  
Surface Chemical Reaction ◽  
Ammonium Carbamate ◽  
Shrinking Core ◽  
Kinetics Of

AbstractThe dissolution of malachite particles in ammonium carbamate (AC) solutions was investigated in a batch reactor, using the parameters of temperature, AC concentration, particle size, and stirring speed. The shrinking core model was evaluated for the dissolution rate increased by decreasing particle size and increasing the temperature and AC concentration. No important effect was observed for variations in stirring speed. Dissolution curves were evaluated in order to test shrinking core models for fluid-solid systems. The dissolution rate was determined as being controlled by surface chemical reaction. The activation energy of the leaching process was determined as 46.04 kJ mol

Kinetics Behavior and Sulfur Transformations of Iron Sulfide during Supercritical Water Oxiation

2012 ◽  
Vol 524-527 ◽  
pp. 1939-1942 ◽  
Author(s):  
Hong He Ma ◽  
Shu Zhong Wang ◽  
Lu Zhou
Keyword(s):  
Activation Energy ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Iron Sulfide ◽  
Reaction Pathway ◽  
Batch Reactor ◽  
Supercritical Water Oxidation ◽  
Experimental Conditions ◽  
Exponential Factor ◽  
Gasification Process

Oxidation of iron sulfide in supercritical water was investigated in the batch reactor. Iron sulfide was converted in two parallel processes: gasification by water and oxidation by oxygen. Assuming that the reaction order of H2O was 0, the activation energy and pre-exponential factor of the gasification process were determined to be 43kJ mol-1 and 22.4 min-1, correspondingly. It is found that above 773K the oxidation process was limited by the mass transfer of O2 to particles surface. Below 773K, with an assumption of zero order in H2O concentration and first-order reaction in oxygen concentration, the activation energy and pre-exponential factor for the rate of oxidation were estimated as154kJ mol-1 and 1.7×106m3 mol-1 min-1, respectively. With supercritical water oxidation under the experimental conditions, the sulfur-containing components in the product were sulfide, sulfite and sulfate, in which sulfide and sulfate were predominant. It is likely to completely convert the sulfur to the sulfate by supercritical water oxidation using high temperature and long reaction time. The reaction pathway of iron sulfide could be expressed as: iron sulfide → sulfide → sulfite → sulfate.

Sign in / Sign up

Export Citation Format

Share Document