scholarly journals Energy Content Of The Domestic Wastewater Sludge Dried In The Thermal Dryer

2018 ◽  
Vol 225 ◽  
pp. 03008
Author(s):  
M.S. Zakaria ◽  
Suhaimi Hassan ◽  
M.N. Faizairi

Domestic Wastewater Sludge (DWS) is considered as one of the largest contributor waste in Malaysia. Converting this waste as an alternative fuel can eliminate the disposal problem and reduce the environmental issue that causes by this waste. However, the initial moisture content in DWS is around 90% and in order to convert this waste into useful solid fuel, the moisture content of this waste must be reduced to 20% and below. Thermal dryer is one of the efficient dryer for the DWS that is capable of drying the huge volume of DWS in a short period of time. This study focused on the energy usage by the thermal dryer with several operating condition and the effect to the Higher Heating Value (HHV) of DWS. Based on the study, the higher heating value of DWS obtained from the experimental of thermal dryer found to be comparable with the results obtained from other biomass types which is around 9-15.86 MJ/kg. After analysis and comparison of the energy from the dried DWS and energy consumed by the dryer, the best operating condition of the thermal dryer was at 275 kW of power rating with speed of 30 and 10 rpm (revolution per minute) of the screw conveyor in the feeder and dryer respectively.

2019 ◽  
Vol 2 (3) ◽  
pp. 954-963
Author(s):  
Aboubaker AbdallaIbrahim Ali ◽  
Hüseyin Akilli

Dewatered domestic wastewater sludge (DDWS) is one of the largest contributors of waste material in the world, and it immediately elevates local environmental problems, especially in the urban area. The conversion of this material into a usable form of green energy, such as syngas through gasification, can be a vital solution. Hence, this method not only solves the environmental issues related to DDWS disposal but also participates as an energy source. To achieve this goal, the essential fuel characterization, which includes initial moisture content, high heating value, ultimate analysis, and proximate analysis, were carried out to assess the potential energy in DDWS. Due to the high expenses of the successful design of the gasifier reactor, and there are no efficient methods to predict the gasification performance, the model of the DDWS gasification process using ASPEN Plus software was developed. As ASPEN Plus software does not contain a built-in gasifier reactor model, a combination of various reactors is used to simulate the gasification processes. These processes were divided out into two stages. In the first stage, DDWS was decomposed into its element by specifying yield distribution. By using Gibbs free energy minimization approach, the gasification reactions were modeled. The current model was validated with the previously published work. From the characterization findings, DDWS showed high initial moisture content 84.64% and potential energy with 16.84 MJ/kg high heating value. The proximate analysis based on the dry base of DDWS exhibited that more than 55.42 % of their mass is composed of volatile materials, and ash content is found to be less than 25.79%.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1044 ◽  
Author(s):  
Marco Manzone ◽  
Fabrizio Gioelli ◽  
Paolo Balsari

Baled pruning residue could be a valid solution to reduce the storage surface area in thermal and electrical power station. This study aimed to analyze the storage performance of pruning residues baled by a round baler considering three orchard tree species (apple, peach, and kiwi) and three different techniques (uncovered, under roof, and wrapped). The storage parameters considered were: moisture content, dry mass, and wood energy content of the material. The initial moisture content of the tree orchard specie (apple, peach, and kiwi) was different: lower for peach (41%) and higher for kiwi (51%). At the end of the storage period, all bales (covered and uncovered) obtained similar values to that of the air (about 20%); wrapped bales have highlighted no moisture content variation. The tested tree species showed a similar initial high heating value (18.70 MJ·kg−1), but a different initial low heating value: lower for kiwi (7.96 MJ kg−1) and higher for peach (10.09 MJ·kg−1). No dry matter losses were observed in all test. Stored pruning residues in bales show good benefits in term of “biofuel” quality independent of the techniques adopted expect for the wrapping system that do not permit adequate drying of the biomass.


2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Agnieszka Zawadzka ◽  
Liliana Krzystek ◽  
Stanisław Ledakowicz

AbstractTo carry out autothermal drying processes during the composting of biomass, a horizontal tubular reactor was designed and tested. A biodrying tunnel of the total capacity of 240 dm3 was made of plastic material and insulated with polyurethane foam to prevent heat losses. Municipal solid waste and structural plant material were used as the input substrate. As a result of autothermal drying processes, moisture content decreased by 50 % of the initial moisture content of organic waste of about 800 g kg−1. In the tested cycles, high temperatures of biodried waste mass were achieved (54–56°C). An appropriate quantity of air was supplied to maintain a satisfactory level of temperature and moisture removal in the biodried mass and high energy content in the final product. The heat of combustion of dried waste and its calorific value were determined in a calorimeter. Examinations of pyrolysis and gasification of dried waste confirmed their usefulness as biofuel of satisfactory energy content.


2021 ◽  
Vol 20 (3) ◽  
pp. 44
Author(s):  
S. Camera ◽  
T. Pineda-Vásquez ◽  
F. M. Bianchi ◽  
L. S. Martins ◽  
E. Virmond ◽  
...  

As communities grow, cities need to increase their capacity to collect and treat domestic wastewater. The need of larger domestic wastewater treatment plants and proper disposal of its solid waste has attracted the scientific community to research about new technologies that will use those systems and waste as a way to generate energy. The moisture content of a fuel effects the combustion products and the energy released by the reaction.  Therefore, in order to make biomass to be a viable fuel option, the technological and scientific challenges of the drying process of wastewater sludge must be faced and overcome so the lowest moisture content level is achieved. Conventional drying processes as for example, direct and indirect thermal drying, are commonly used. However, other processes using renewable energy as for example solar drying are also being studied by the scientist around the world. Moisture content, physical-chemical properties as for example, heating values, composition, ash fusibility are all relevant properties taken into consideration when choosing a fuel for a specific application. The herein review is intended to present some existing domestic wastewater drying processes, alternative ways of improving the efficiency of those processes.


Author(s):  
Nayara Vilela Avelar ◽  
Ana Augusta Passos Rezende ◽  
Antonio Marcos de Oliveira Siqueira ◽  
Cláudio Mudadu Silva ◽  
Angélica de Cássia Oliveira Carneiro

Considerable increases in industrial and urban wastewater sludge generation in recent years require proper treatment, such as thermal drying, and disposal. The sludge drying is a complex process involving simultaneous and coupled heat and mass transfer, which can be modeled by taking into account mass and heat balances, and assuming that water diffuses according to kinetic laws. This research implemented a simulation model for biosludge drying processes to predict the temperature and moisture distribution inside the biosludge, using the COMSOL Multiphysics® simulation program v5.2. A parametric analysis was carried out to determine the effect of initial moisture content on biosludge final temperature and moisture reduction. The simulated temperature and moisture content were experimentally validated and good agreement was observed between the simulation and experimental results. This model is a useful tool to optimize the drying process and develop better strategies for the control of the system.


Author(s):  
L. Hübschen

AbstractThe present paper shows the detectable factors on which a sorption isotherm depends. Even if it is well-known that a sorption isotherm is most essentially conditioned by influences of the respective tobacco variety, other factors, such as temperature, initial moisture content, or fibre dimension, play a part as well. In general, a sorption isotherm constitutes a ''summation'' of such factors and, in the end, a combination of desorption and adsorption if the tobacco is dried or moistened from the average commercial moisture content. The tobacco hysteresis is experimentally investigated and discussed


Agrotek ◽  
2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Wilson Palelingan Aman

<em>A research about cocoa beans drying used solar tunnel dryer with photovoltaic module driven have conducted in Manokwari. Solar tunnel dryer used in this research adapted from type Hohenheim with photovoltaic module and integrated air heat collector has been installed at the Department of Agricultural Technology, Papua State University Manokwari to dried cocoa beans. The objectives of this research were to design solar tunnel dryer and evaluate it�s performance in dryed cocoa beans. The result obtained was a new construction of solar tunnel dryer for cocoa beans with dimensions 6 m of length and 0,9 m of wide. The dryer completed with photovoltaic module to drive the blowers of hot drying air. �Performance test of the dryer showed that drying of 10 kg of cocoa beans with initial moisture content about 70% wet basis needed 13 hours of drying time to achieved final moisture content about 7,17% wet basis. The drying time achieved was faster compared than traditional solar drying that needed 20 hours of drying time. The maximum temperature achieved in drying chamber was 60 <sup>o</sup>C.</em>


Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1590 ◽  
Author(s):  
Angelo Del Giudice ◽  
Andrea Acampora ◽  
Enrico Santangelo ◽  
Luigi Pari ◽  
Simone Bergonzoli ◽  
...  

Drying is a critical point for the exploitation of biomass for energy production. High moisture content negatively affects the efficiency of power generation in combustion and gasification systems. Different types of dryers are available however; it is known that rotary dryers have low cost of maintenance and consume 15% and 30% less in terms of specific energy. The study analyzed the drying process of woody residues using a new prototype of mobile rotary dryer cocurrent flow. Woodchip of poplar (Populus spp.), black locust (Robinia pseudoacacia L.), and grapevine (Vitis vinifera L.) pruning were dried in a rotary drier. The drying cycle lasted 8 h for poplar, 6 h for black locust, and 6 h for pruning of grapevine. The initial biomass had a moisture content of around 50% for the poplar and around 30% for grapevine and black locust. The study showed that some characteristics of the biomass (e.g., initial moisture content, particle size distribution, bulk density) influence the technical parameters (i.e., airflow temperature, rate, and speed) of the drying process and, hence, the energy demand. At the end of the drying process, 17% of water was removed for poplar wood chips and 31% for grapevine and black locust wood chips. To achieve this, result the three-biomass required 1.61 (poplar), 0.86 (grapevine), and 1.12 MJ kgdry solids−1 (black locust), with an efficiency of thermal drying (η) respectively of 37%, 12%, and 27%. In the future, the results obtained suggest an increase in the efficiency of the thermal insulation of the mobile dryer, and the application of the mobile dryer in a small farm, for the recovery of exhaust gases from thermal power plants.


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Monika Aniszewska ◽  
Krzysztof Słowiński ◽  
Ewa Tulska ◽  
Witold Zychowicz

AbstractThe paper proposes the use of microwave irradiation to lower the initial moisture content of wood chips. The study involved willow and fir chips fractionated by means of a sieve separator and unfractionated ash chips. The wood chips were exposed to a constant microwave power of 800 W for 30 s, 60 s, 120 s and 180 s. The chips were weighed before and after irradiation to measure loss of moisture. It was found that the decline in moisture content increased with wood chip size for a given irradiation time and microwave power. The initial moisture content of wood chips was not found to significantly affect loss of moisture as the drying rates of wood chips with higher and lower moisture content exposed to microwaves were not statistically different. The results showed that irradiation intensity increased with the time of exposure to microwaves and unit radiant energy per unit of evaporated moisture decreased with increasing wood chip size in the 3.15–31.50 mm range.


Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro

Solar drying and convective oven drying of cherry tomatoes (Solanum lycopersicum) were compared. The changes in the chemical parameters of tomatoes and principal drying parameters were recorded during the drying process. Drying curves were fitted to several mathematical models, and the effects of air temperature during drying were evaluated by multiple regression analyses, comparing to previously reported models. Models for drying conditions indicated a final water content of 30% (semidry products) and 15% (dry products) was achieved, comparing sun-drying and convective oven drying at three different temperatures. After 26–28 h of sun drying, the tomato tissue had reached a moisture content of 15%. However, less drying time, about 10–11 h, was needed when starting with an initial moisture content of 92%. The tomato tissue had high ORAC and polyphenol content values after convective oven drying at 60 °C. The dried tomato samples had a satisfactory taste, color and antioxidant values.


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