scholarly journals Integrating sludge drying in biomass fueled CHP plants

2020 ◽  
Author(s):  
Jinshan Wang ◽  
Chaudhary Awais Salman ◽  
Bin Wang ◽  
Hailong Li ◽  
Eva Thorin
Keyword(s):  
Moisture Content ◽  
Flue Gas ◽  
Feeding Rate ◽  
Waste Heat ◽  
Thermal Conversion ◽  
Water Evaporation ◽  
Drying Process ◽  
Sludge Drying ◽  
Dried Sludge ◽  
Downstream Processes

Abstract Handling sludge through thermal conversion is environmentally friendly, which, however, requires sludge drying. This work proposed to use the waste heat of flue gas (FG) to dry sludge. The integration of sludge drying in biomass fueled combined heat and power (CHP) plants can clearly affect the performance of downstream processes in FG cleaning, such as flue gas quench (FGQ) and flue gas condenser, and further affect the energy efficiency of CHP. In order to understand the influence, a mathematical model and an Aspen PLUS model were developed to simulate the drying process and the CHP, respectively. Based on simulations, it is found that the increase of feeding rate of sludge and the moisture content of sludge after drying can decrease the water evaporation in FGQ. An increase in the feeding rate of sludge in combination with a drop of moisture content of sludge after drying can decrease the heat recovery from FG. When using dried sludge to replace biomass, the amount of saving could be influenced by the moisture content after drying and the flow rate of sludge. Simulation results show that drying sludge to a moisture content of 40% leads to the maximum biomass saving.

scholarly journals Thermo-economic analysis of an efficient lignite-fired power system integrated with flue gas fan mill pre-drying

2018 ◽  
Author(s):  
Junjie Yan ◽  
Xiaoqu Han ◽  
Jiahuan Wang ◽  
Ming Liu ◽  
Sotirios Karellas
Keyword(s):  
Moisture Content ◽  
Economic Analysis ◽  
Power System ◽  
Energy Saving ◽  
Flue Gas ◽  
Power Plants ◽  
Waste Heat ◽  
Low Rank ◽  
Analysis Model ◽  
Energy Saving Potential

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

An Innovative Technology Development for Building Humidification and Energy Efficiency

2012 ◽  
Author(s):  
Dexin Wang ◽  
Ainan Bao ◽  
William Liss
Keyword(s):  
Energy Consumption ◽  
Flue Gas ◽  
Microbial Growth ◽  
Waste Heat ◽  
Water Evaporation ◽  
Innovative Technology ◽  
Residential Home ◽  
Furnace Efficiency ◽  
Mineralized Water ◽  
External Water

Currently, the most widely used residential humidification technologies are forced air furnace mounted bypass wetted media, spray mist, and steam humidifiers. They all use city water as a water source and require furnace heat or electricity to evaporate the water. Mineral deposition, white dust, and microbial growth problems are associated with these humidifiers. For commercial building humidification, de-mineralized water is typically used for humidification equipment like steam heat exchangers, fogging system, electric, and ultrasonic humidifiers. Therefore, in addition to the energy consumption for the water evaporation, energy is also needed to produce the high quality de-mineralized water. An innovative technology called Transport Membrane Humidifier (TMH), has been developed by the authors to humidify home air without external water and energy consumption, while simultaneously recovering waste heat from the home furnace flue gas to enhance the furnace efficiency. The TMH technology is based on our previous extensive study on nanoporous membrane water vapor separation from combustion flue gas, and a design for residential home humidification application was first developed. It has been proved by both laboratory prototype testing for long term performance, and by two occupied single family home demonstrations for two heating seasons. The technology can provide whole house humidification without any external water consumption, and at the same time boost the furnace efficiency. Compared with conventional furnace mounted humidifiers, the TMH does not need additional furnace fuel for the water evaporation, no white dust in the home, no microbial growth since there is no standing water involved. Therefore, it is an innovative technology that can provide energy saving, water saving and healthy building humidification.

Numerical Research on the Drying Process of Single Lignite Particle by High Temperature Flue Gas

2013 ◽  
Vol 732-733 ◽  
pp. 250-253
Author(s):  
Ai Xia Dong ◽  
Shou Yu Zhang ◽  
Xi Guo ◽  
Hong Jun Zheng ◽  
Wen Xiang Deng ◽  
...  
Keyword(s):  
High Temperature ◽  
Flue Gas ◽  
Large Scale ◽  
Solution Process ◽  
Water Evaporation ◽  
Drying Process ◽  
Stable Domain ◽  
Accelerate Convergence ◽  
Volume Method ◽  
The Mathematical Model

The technology of downstream vibrated bed dryer with high temperature flue gas has been applied successfully by CPI Mengdong Energy Group Co., LTD for the large scale upgrading of Baiyinhua lignite. It is very necessary to study the drying process of a single lignite particle by high temperature flue gas. Based on finite volume method, the numerical simulation was applied in the lignite drying process and the mathematical model for the drying process of a single spherical lignite particle with high temperature flue gas was developed. Here, the lignite particle was divided into dry region and wet region by water evaporation interface. To accelerate convergence and make stable domain larger and truncation error smaller in the solution process, Crank-Nicolson six-point difference iteration method was used to solve the model.

scholarly journals Computational modeling of biosludge drying

2021 ◽  
Vol 9 (8) ◽  
pp. 219-232
Author(s):  
Nayara Vilela Avelar ◽  
Ana Augusta Passos Rezende ◽  
Antonio Marcos de Oliveira Siqueira ◽  
Cláudio Mudadu Silva ◽  
Angélica de Cássia Oliveira Carneiro
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Wastewater Sludge ◽  
Moisture Distribution ◽  
Drying Process ◽  
Urban Wastewater ◽  
Complex Process ◽  
Simulated Temperature ◽  
Sludge Drying ◽  
Good Agreement

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.

An Innovative Technology Development for Building Humidification and Energy Efficiency

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Dexin Wang ◽  
Ainan Bao ◽  
William Liss
Keyword(s):  
Energy Consumption ◽  
Flue Gas ◽  
Microbial Growth ◽  
Waste Heat ◽  
Water Evaporation ◽  
Innovative Technology ◽  
Residential Home ◽  
Furnace Efficiency ◽  
Demineralized Water ◽  
External Water

Currently, the most widely used residential humidification technologies are forced air furnace mounted bypass wetted media, spray mist, and steam humidifiers. They all use city water as a water source and require furnace heat or electricity to evaporate the water. Mineral deposition, white dust, and microbial growth problems are associated with these humidifiers. For commercial building humidification, demineralized water is typically used for humidification equipment like steam heat exchangers, fogging system, electric, and ultrasonic humidifiers. Therefore, in addition to the energy consumption for water evaporation, energy is also needed to produce the high quality demineralized water. An innovative technology called transport membrane humidifier (TMH) has been developed by the authors to humidify home air without external water and energy consumption, while simultaneously recovering waste heat from the home furnace flue gas to enhance furnace efficiency. The TMH technology is based on our previous extensive study on nanoporous membrane water vapor separation from combustion flue gas, and a design for residential home humidification application was first developed. It has been proved by both laboratory prototype testing for long term performance and by two occupied single family home demonstrations for two heating seasons. The technology can provide whole house humidification without any external water consumption, and at the same time, boost the furnace efficiency. Compared with conventional furnace mounted humidifiers, the TMH does not need additional furnace fuel for the water evaporation, does not introduce white dust to a home, and poses no microbial growth concerns since there is no standing water involved. This innovative technology can provide several benefits simultaneously, which include energy saving, water saving, and healthy building humidification.

scholarly journals Issues related to waste sewage sludge drying under superheated steam

2015 ◽  
Vol 17 (4) ◽  
pp. 5-14 ◽  
Author(s):  
Ihsan Hamawand ◽  
Wilton Pereira da Silva ◽  
Friederike Eberhard ◽  
Diogenes L. Antille
Keyword(s):  
Particle Size ◽  
Sewage Sludge ◽  
Moisture Content ◽  
Superheated Steam ◽  
Final Particle ◽  
Screw Feeder ◽  
Rotary Drum ◽  
Sludge Drying ◽  
Dried Sludge ◽  
Mesh Sieve

Abstract Sewage sludge was dried in a rotary drum dryer under superheated steam. Particle size and moisture content were shown to have significant influences on sticking and agglomeration of the materials. Pouring partially dried sludge (70–80% moisture content, wet basis) directly into the screw feeder of the drum dryer resulted in a significant sticking to the surface of the drum and the final particle size of the product was greater than 100 mm in diameter. The moisture content of this product was slightly less than its initial value. To overcome this issue, the sludge was mixed with lignite at variety ratios and then chopped before being introduced to the feeding screw. It was found that mixing the sludge with lignite and then sieving the chopped materials through a four millimetre mesh sieve was the key to solve this issue. This technique significantly reduced both stickiness and agglomeration of the material. Also, this enabled for a significant reduction in moisture content of the final product.

scholarly journals Pemanfaatan panas kondenser pada pengering beku vakum

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Dinni Agustina ◽  
Roe Dwi Dhewaji ◽  
Awaluddin Martin
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Waste Heat ◽  
Heating System ◽  
Food Preservation ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Drying Process ◽  
Self Heating ◽  
Secondary Drying

Pengering beku vakum (Freeze vacuum drying) merupakan salah satu metode pengeringan terbaik untuk pengawetan bahan makanan. Selain menjadi salah satu solusi untuk teknologi pasca panen, freeze vacuum drying juga mampu untuk meningkatkan nilai jual suatu produk. Penelitian ini bertujuan untuk mengembangkan pengering beku vakum yang menggunakan sistem pemanasan mandiri (self heating system) dengan pemanfaatan panas kondenser. Pada awal penelitian tanpa proses secondary drying dibutuhkan waktu 24 jam untuk menghilangkan kadar air sebanyak 62% dari produk dengan temperature -5oC. Penelitian berikutnya dengan memanfaatkan panas buang kondenser dan menggunakan proses secondary drying dibutuhkan waktu 4 jam untuk mengurangi kadar air pada produk sebesar 78% pada temperature -9oC. Freeze vacuum drying is one of the best drying methods for food preservation. Besides being one of the solutions for post-harvest technology, freeze vacuum drying is also able to increase the sale value of a product. The aim of this research is to develop a freeze vacuum drying using a self-heating system by utilizing a heat of condenser. At the beginning of the research without secondary drying process, it took 24 hours to remove 62% of water content from products with a temperature of -5oC. In further research by utilized waste heat of condenser and by using secondary drying process, it took 4 hour to reduce 78% moisture content of product at -9oC.

scholarly journals Parameters affecting biomass drying during combustion in moving grate furnaces

Energetika ◽  
2019 ◽  
Vol 65 (1) ◽  
Author(s):  
Lina Vorotinskienė
Keyword(s):  
Moisture Content ◽  
Solid Fuel ◽  
Flue Gas ◽  
Experimental Studies ◽  
Drying Process ◽  
High Quality ◽  
Air Supply ◽  
Constant Moisture Content ◽  
Increasing Demand ◽  
Gas Recirculation

The most efficient way so far to extract energy from renewable sources is combustion of solid fuel. Solid fuel furnaces of moderate capacity (5–10 MW) equipped with reciprocating grates are most popular. Grate combustion is a well-developed technology; however, to burn biofuel in this type of furnaces in the optimal and safe way, the fuel must be of high quality and have at least constant moisture content. However, increasing demand for biofuel results in increasing prices. To remain in the market and to stay competitive, heat producers choose to utilise moist biofuel of lower quality, whose moisture content can vary and reach up to 60% wt. The burning on the grate of such biofuel is complicated as the drying process occupies most of the space in the furnace. The purpose of this work was to analyse processes taking place in a furnace, such as: primary air supply, influence of flue gas recirculation and radiation from hot surfaces of the furnace to biofuel drying. Analysis of the data obtained would provide technical decisions facilitating optimal fuel combustion in a furnace without additional investments. Analysis of biofuel drying was performed in an experimental setup with a fixed fuel bed. The experiments were performed with wood chips and four different drying fluid temperatures. The results of experimental studies have shown that the drying rate of biofuels upper layers is strongly influenced by radiation from hot surfaces and the moisture content of the sample decreases by 18% wt.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

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