scholarly journals Drying characteristics of sludge in a rotary drum for fast-drying application

2020 ◽  
pp. 303-303
Author(s):  
Yongli Xiao ◽  
Hualin Wang ◽  
Shengan Deng ◽  
Fuyong Su ◽  
Zhi Wen

High-temperature metallurgical slag (temperature, > 1450 ?C) and high-moisture sludge (moisture content, > 80 wt%) are common wastes with huge outputs. Many problems, such as high cost, low level of harmlessness, and low efficiency, are encountered in current treatment methods. If these wastes can be recycled, they can be valuable secondary resources. Therefore, using the drum apparatuses to treat these two kinds of wastes is proposed. The process uses waste heat of slag to dry sludge with high moisture content and is a kind of alternative circulation treatment technology in which steel balls are used as ball milling media and intermediate heat carriers. Besides, this technology can break up slag or sludge in real time, thereby ensuring high heat or mass transfer rate. This study presents an experimental investigation of the dynamic drying process of wet sludge mixed with hot steel balls in a rotary drum. The relationship of operation parameters (including sludge moisture content, sludge treatment mass, steel ball diameter, and rotary speed of drum) and drying effect is obtained. There are three kinds of final drying results: completely dried to powder, few sludge agglomerations, and sludge-to-wall adhesion. If the operating parameters are set well, the sludge could be efficiently and completely dried and eventually in powder form.

Author(s):  
Dexin Wang ◽  
William Liss ◽  
Ainan Bao

A new waste heat and water recovery technology based on a nanoporous ceramic membrane water vapor separation mechanism was developed, to extract the water vapor and its latent heat from low temperature high moisture content waste gas streams. For the water reclamation process, water vapor condenses inside the membrane pores and passes through to the permeate side which is in direct contact with a low-temperature water stream. Contaminants such as CO2, O2, NOx, and SO2 are inhibited from passing through the membrane by its high selectivity. The recovered water is of high quality and mineral free, therefore can be used as supplemental makeup water for almost all industrial processes. The membrane based technology has been first developed and demonstrated for industrial boiler flue gas heat and water recovery. Now it is being developed for wider applications, from residential humidification, commercial laundry, biomass production to utility boilers. The increased application areas will greatly enhance waste heat and water recovery potentials worldwide, to save both energy and water, and benefit the global environment. In this paper, the technology development process, and several demonstrations for different applications are discussed in details.


2017 ◽  
Vol 12 (3) ◽  
pp. 400 ◽  
Author(s):  
Valdiney Cambuy Siqueira ◽  
Flávio Meira Borém ◽  
Guilherme Euripedes Alves ◽  
Eder Pedroza Isquierdo ◽  
Afonso Celso Ferreira Pinto ◽  
...  

Objetivou-se, com o presente trabalho, propor um novo método de processamento e secagem, assim como avaliar o comportamento dos grãos submetidos a este processo, por meio da taxa de redução de água e do ajuste de diferentes modelos matemáticos aos dados experimentais da secagem. Os frutos colhidos no estágio maduro foram divididos em três lotes. O primeiro foi seco continuamente à temperatura de 40±1 °C. O segundo consiste na secagem do café natural até os teores de água de 0,56±0,02, 0,41±0,02, 0,28±0,02 e 0,20±0,02 decimal (base seca, b.s.), seguido de beneficiamento e secagem contínua nas temperaturas de 35±1 ºC e 40±1 ºC. O terceiro lote correspondeu à secagem contínua do café descascado e desmucilado na temperatura de 40±1 °C. Em todos os lotes, a secagem foi encerrada quando os grãos atingiram o teor de água de 0,12±0,05 (b.s.). Aos dados experimentais da secagem foram ajustados dez modelos matemáticos utilizados para representação da secagem dos produtos agrícolas. Além da representação da cinética de secagem foi avaliada a taxa de redução de água dos grãos. Conclui-se que a taxa de redução de água é maior para a temperatura de secagem de 40±1 °C, especialmente para maiores teores de água. O tempo total de secagem do café beneficiado com alto teor de água é expressivamente reduzido, quando comparado ao tempo de secagem completa do café natural. O modelo de Midilli descreve satisfatoriamente a cinética de secagem do café beneficiado.


1965 ◽  
Vol 7 (3) ◽  
pp. 385-387 ◽  
Author(s):  
T. R. Preston ◽  
H. B. Bowers ◽  
N. A. MacLeod ◽  
Euphemia B. Phillip

The use of barley for intensive beef production, as described by Preston, Aitken, Whitelaw, Macdearmid, MacLeod and Philip (1963) is now a well established practice, but one of the hazards of this feeding system is bloat. There is evidence that the risk of this condition is accentuated if the barley husk is broken down too finely as happens if the grain is ground (Preston, Macdearmid and MacLeod, 1963; Preston, 1964). It was therefore recommended that barley should be processed in a roller mill and that the moisture content should be at least 16% (Preston, 1963), for if the grain is drier than this it is difficult to prevent excessive shattering and destruction of the husk. Suitable containers, which can be sealed in order to ensure anaerobic conditions and so overcome the problem of storing damp grain (greater than 16% moisture) have additional advantages at harvest since they can be filled quickly and easily. The purpose of this experiment was to evaluate the nutritive value of barley stored under these conditions.


2014 ◽  
Vol 124 ◽  
pp. 267-274 ◽  
Author(s):  
Seung-Hyun Moon ◽  
In-Soo Ryu ◽  
Seung-Jae Lee ◽  
Tae-In Ohm

Author(s):  
Ana Sakura Zainal Abidin ◽  
◽  
Mohamad Zulhatta Kifli ◽  
Annisa Jamali ◽  
Rasli Muslimen ◽  
...  

Rotary drum dryer has been identified as hygienic and practical method to dry black pepper. The quality of black pepper is defined based on the chemical properties and moisture content. This research aims to develop a control system for black pepper rotary drum dryer. The dried pepper should meet the specific 12% moisture content while the heating temperature must be kept below 550C. The requirement of 12% moisture content is equivalent to 30% of the remaining weight of the pepper (final weight). The developed system uses Arduino Mega 2560 REV board as a microcontroller. A type K thermocouple with MAX6675 thermocouple amplifier and S-type load cells (TAS501) with HX711 load cell amplifier are used as input sensor to microcontroller. The system keeps measuring the current weight until it hit the targeted final weight. Two set of experiments that are using 500 g and 1500 g of pre-treated pepper were conducted to verify the system. As a result, the dryer was successful to work within the desired temperature and it stop operating just after the samples reached 12% of the moisture content. The finding has proven a shorten of drying time from 4 to 7 days when using the traditional method to the current 3 – 5 hours only when using the developed system. Hence, this is an improved method achieved to a quick drying of the black pepper.


Author(s):  
Junjie Yan ◽  
Xiaoqu Han ◽  
Jiahuan Wang ◽  
Ming Liu ◽  
Sotirios Karellas

Lignite is a domestic strategic reserve of low rank coals in many countries for its abundant resource and competitive price. Combustion for power generation is still an important approach to its utilization. However, the high moisture content always results in low efficiencies of lignite-direct-fired power plants. Lignite pre-drying is thus proposed as an effective method to improve the energy efficiency. The present work focuses on the flue gas pre-dried lignite-fired power system (FPLPS), which is integrated with fan mill pulverizing system and waste heat recovery. The thermo-economic analysis model was developed to predict its energy saving potential at design conditions. The pre-drying upgrade factor was defined to express the coupling of pre-drying system with boiler system and the efficiency improvement effect. The energy saving potential of the FPLPS, when applied in a 600 MW supercritical power unit, was determined to be 1.48 %-pts. It was concluded that the improvement of boiler efficiency mainly resulted from the lowered boiler exhaust temperature after firing pre-dried low moisture content lignite and the lowered dryer exhaust gas temperature after pre-heating the boiler air supply. Keywords: lignite; pre-drying; thermodynamic analysis; thermo-economics


2020 ◽  
Vol 67 (2) ◽  
pp. 73-77
Author(s):  
Zarife Bajraktari-Gashi ◽  
Muharrem Zabeli ◽  
Behram Halilaj

AbstractDuring 1984–1997, the ferronickel plant in Drenas used iron-nickel ore from the mines of the Republic of Kosovo: Glavica and Çikatove (Dushkaje and Suke) mines. However, during the years 2007–2017, when the plant started operating from the cessation of production, which was from 1998 to 2007, some types of iron-nickel ores from different countries began to be used, starting from iron-nickel ores from Kosovo, iron-nickel ores from Albania, ores from Indonesia, ores from the Philippines, ores from Guatemala, ores from Turkey and ores from Macedonia. The ore composition, however, is mainly oxide-laterite ore. Iron-nickel ores in the plant are characterised by high moisture content, a very important factor influencing the process of scraping the charge in rotary kilns and presenting in general. Among the iron-nickel ore used in the ferronickel plant, the ores from Albania are characterised due to their low moisture content when compared with the other ores as well as the high content of iron oxides, which affect the temperature rise inside the furnaces, as the iron ores play an important role in the pre-casting process in rotary kilns.


Sign in / Sign up

Export Citation Format

Share Document