Modeling of Waste-to-Energy Combustion With Continuous Variation of the Solid Waste Fuel

2003 ◽  
Author(s):  
Masato Nakamura ◽  
Hanwei Zhang ◽  
Karsten Millrath ◽  
Nickolas J. Themelis
Keyword(s):  
Solid Waste ◽  
Percolation Theory ◽  
Combustion Process ◽  
Solid Particles ◽  
Continuous Variation ◽  
Waste To Energy ◽  
Stochastic Representation ◽  
Mean Values ◽  
Transient Phenomena ◽  
Waste Particles

A mathematical model of a mass-burn, waste-to-energy combustion chamber has been developed that includes stochastic representation of the variability of the fuel (municipal solid waste, MSW). The drying, pyrolysis, gasification and combustion processes on the moving grate are governed by several factors such as proximate and ultimate analysis, particle size, moisture, heating value, and bulk density, all of which change continuously. This extreme variability has not been considered in past mathematical models of WTE combustion that used mean values of the MSW properties. The Monte Carlo stochastic method has been applied to provide a time series description of the continuous variation of solid wastes at the feed end of the traveling grate. The combustion of the solid particles on the grate is simulated using percolation theory. The feed variation and the percolation theory models are combined with the FLIC two-dimensional bed model developed by Sheffield University to project the transient phenomena in the bed, such as the break-up of waste particles and the channeling of combustion air throughout the bed, and their effects on the combustion process.

Modeling of Solid Waste Flow and Mixing on the Traveling Grate of a Waste-to-Energy Combustion Chamber

2004 ◽  
Author(s):  
Masato Nakamura ◽  
N. J. Themelis
Keyword(s):  
Solid Waste ◽  
Markov Chain Model ◽  
Combustion Process ◽  
Bottom Layer ◽  
Combustion Efficiency ◽  
Waste To Energy ◽  
Chain Model ◽  
Municipal Solid Wastes ◽  
Waste Flow ◽  
Waste Particles

Mixing of the highly non-homogeneous municipal solid wastes (MSW) on the traveling grate of mass-burn combustion chambers assists the combustion process in waste-to-energy (WTE) facilities. A matrix-based Markov chain model was developed to simulate particle flow and mixing as the solid waste particles travel over a reverse acting Martin grate. The model was used to project the pathway of a solid waste particle over a time series, in the bottom layer of the bed that is in contact with the bars of the grate. Further analytical and experimental work is planned in order to develop this model to a useful tool for designing future moving grate systems and increasing the combustion efficiency of existing WTEs.

Mixing and Residence Time Analysis of Municipal Solid Waste Particles by Different Numbers of Moving Bars and Reciprocation Speeds of a Grate System

2011 ◽  
Author(s):  
Masato R. Nakamura ◽  
Marco J. Castaldi
Keyword(s):  
Diffusion Coefficient ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Residence Time ◽  
Combustion Process ◽  
Waste To Energy ◽  
Size Segregation ◽  
Particle Mixing ◽  
Combustion Technology ◽  
Waste Particles

The grate systems of waste-to-energy (WTE) mass-burn combustion chambers, which historically stem from coal combustion technology, have an important role in controlling the mixing of heterogeneous MSW during the combustion process. They are designed for providing efficient flow and mixing of Municipal Solid Waste (MSW) in the combustion chamber. This study presents results from a numerical analysis for grate design and chamber operation, i.e., number of reciprocating bars and reciprocation speed that influence the degree of mixing and residence time of MSW particles. A particle-based bed model of MSW and a physical model of reverse-acting grate were used in order to quantify the mixing diffusion coefficient of MSW particles. We analyzed the particle mixing with different parameters: particle size (d = 6–22 cm diameter), reciprocation speed of moving bars (Rr = 0–90 recip./h), and number of moving bars (Nb = 1–16 bars). According to the size segregation in the particle mixing process in the MSW bed, the undersized waste particles in the MSW bed on the reverse-acting grate have a higher diffusion coefficient than those of oversized and mean size particles. Also the number of moving bars, Nb, as well as reciprocation speed, Rr, were quantitatively related to a diffusion coefficient equation for MSW particle mixing.

Numerical Analysis of Size Reduction of Municipal Solid Waste Particles on the Traveling Grate of a Waste-to-Energy Combustion Chamber

2006 ◽  
Author(s):  
Masato Nakamura ◽  
Marco J. Castaldi ◽  
Nickolas J. Themelis
Keyword(s):  
Particle Size ◽  
Municipal Solid Waste ◽  
Combustion Chamber ◽  
Solid Waste ◽  
Size Reduction ◽  
Waste To Energy ◽  
Size Change ◽  
Model Combining ◽  
Shrinking Core ◽  
Waste Particles

The size reduction of municipal solid waste (MSW) particles on the reverse acting traveling grate of a waste-to-energy (WTE) combustion chamber was estimated by means of a numerical model combining the particle size distributions (PSD) of MSW and combustion residues and the Shrinking Core Model (SCM). This new integrated model was used to simulate the particle behavior on the grate. During their travel on the moving grate, the sizes of the particles are reduced by combustion, breakage, and compaction. This study shows the calculation of the particle size change using this model and comparison of the numerically derived PSDs of MSW and ash particles with experimental data. There is good agreement between calculated and measured values.

A Review : Sustainability from Waste

2019 ◽  
pp. 134-155
Author(s):  
Kriti Jain ◽  
Chirag Shah
Keyword(s):  
Waste Management ◽  
Solid Waste ◽  
Rural Areas ◽  
Waste To Energy ◽  
Waste Generation ◽  
Material Resources ◽  
Waste Dumps ◽  
Waste Segregation ◽  
Treatment And Disposal ◽  
Engineered Landfill

The increasing volume and complexity of waste associated with the modern economy as due to the ranging population, is posing a serious risk to ecosystems and human health. Every year, an estimated 11.2 billion tonnes of solid waste is collected worldwide and decay of the organic proportion of solid waste is contributing about 5 per cent of global greenhouse gas emissions (UNEP). Poor waste management - ranging from non-existing collection systems to ineffective disposal causes air pollution, water and soil contamination. Open and unsanitary landfills contribute to contamination of drinking water and can cause infection and transmit diseases. The dispersal of debris pollutes ecosystems and dangerous substances from waste or garbage puts a strain on the health of urban dwellers and the environment. India, being second most populated country of the world that too with the lesser land area comparatively, faces major environmental challenges associated with waste generation and inadequate waste collection, transport, treatment and disposal. Population explosion, coupled with improved life style of people, results in increased generation of solid wastes in urban as well as rural areas of the country. The challenges and barriers are significant, but so are the opportunities. A priority is to move from reliance on waste dumps that offer no environmental protection, to waste management systems that retain useful resources within the economy [2]. Waste segregation at source and use of specialized waste processing facilities to separate recyclable materials has a key role. Disposal of residual waste after extraction of material resources needs engineered landfill sites and/or investment in waste-to-energy facilities. This study focusses on the minimization of the waste and gives the brief about the various initiations for proper waste management system. Hence moving towards the alternatives is the way to deal with these basic problems. This paper outlines various advances in the area of waste management. It focuses on current practices related to waste management initiatives taken by India. The purpose of this article put a light on various initiatives in the country and locates the scope for improvement in the management of waste which will also clean up the unemployment.

Municipal solid waste-to-energy processing for a circular economy in New Zealand

2021 ◽  
Vol 145 ◽  
pp. 111080
Author(s):  
M.T. Munir ◽  
Ahmad Mohaddespour ◽  
A.T. Nasr ◽  
Susan Carter
Keyword(s):  
New Zealand ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Circular Economy ◽  
Waste To Energy ◽  
Energy Processing

Comparison of trace element mobility from MSWI ash before and after plasma vitrification

2021 ◽  
pp. 0734242X2110115
Author(s):  
Wesley N Oehmig ◽  
Justin Roessler ◽  
Abdul Mulla Saleh ◽  
Kyle A Clavier ◽  
Christopher C Ferraro ◽  
...  
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Waste Incineration ◽  
Waste To Energy ◽  
Air Pollution Control ◽  
Plasma Arc ◽  
Municipal Solid Waste Incineration ◽  
Trace Element Mobility ◽  
Before And After ◽  
Air Pollution Control Residues

A common perception of plasma arc treatment systems for municipal solid waste incineration ash is that the resulting vitrified slag is inert from an environmental perspective. Research was conducted to examine this hypothesis and to assess whether reduced pollutant release results from pollutant depletion during the process of the ash with plasma, or encapsulation in the glassy vitrified matrix. The concentrations of four discrete municipal solid waste incineration ash samples before and after plasma arc vitrification in a bench-scale unit were compared. Slag and untreated ash samples were leached using several standardized approaches and mobility among the four metals of interest (e.g. As, Cd, Pb and Sb) varied across samples, but was generally high (as high as 100% for Cd). Comparison across methods did not indicate substantial encapsulation in the vitrified slag, which suggests that reduced pollutant release from plasma arc vitrified slag is due to pollutant depletion by volatilization, not encapsulation. This has significant implications for the management of air pollution control residues from waste-to-energy facilities using plasma arc vitrification.

scholarly journals A Techno-Economic Evaluation of Municipal Solid Waste (MSW) Conversion to Energy in Indonesia

2021 ◽  
Vol 13 (13) ◽  
pp. 7232
Author(s):  
Muhammad Mufti Azis ◽  
Jonas Kristanto ◽  
Chandra Wahyu Purnomo
Keyword(s):  
Economic Evaluation ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Energy Recovery ◽  
Capital Investment ◽  
Electricity Price ◽  
Waste To Energy ◽  
Operational Cost ◽  
Internal Rate Of Return ◽  
Sensitive Factor

Municipal solid waste (MSW) processing is still problematic in Indonesia. From the hierarchy of waste management, it is clear that energy recovery from waste could be an option after prevention and the 5R (rethink, refuse, reduce, reuse, recycle) processes. The Presidential Regulation No 35/2018 mandated the acceleration of waste-to-energy (WtE) plant adoption in Indonesia. The present study aimed to demonstrate a techno-economic evaluation of a commercial WtE plant in Indonesia by processing 1000 tons of waste/day to produce ca. 19.7 MW of electricity. The WtE electricity price is set at USD 13.35 cent/kWh, which is already higher than the average household price at USD 9.76 cent/kWh. The capital investment is estimated at USD 102.2 million. The annual operational cost is estimated at USD 12.1 million and the annual revenue at USD 41.6 million. At this value, the internal rate of return (IRR) for the WtE plant is 25.32% with a payout time (PoT) of 3.47 years. In addition, this study also takes into account electricity price sales, tipping fee, and pretreatment cost of waste. The result of a sensitivity analysis showed that the electricity price was the most sensitive factor. This study reveals that it is important to maintain a regulated electricity price to ensure the sustainability of the WtE plant in Indonesia.

scholarly journals Energy Treatment of Solid Municipal Waste in Combination with Biomass by Decentralized Method with the Respect to the Negative Effects on the Environment

2021 ◽  
Vol 13 (8) ◽  
pp. 4405
Author(s):  
Miroslav Rimar ◽  
Olha Kulikova ◽  
Andrii Kulikov ◽  
Marcel Fedak
Keyword(s):  
Heavy Metals ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Process Analysis ◽  
Combustion Process ◽  
Municipal Waste ◽  
Negative Effects ◽  
Combustion Properties ◽  
Polycyclic Aromatic ◽  
Fuel Mixtures

Waste is a product of society and one of the biggest challenges for future generations is to understand how to sustainably dispose of large amounts of waste. The main objective of this study was to determine the possibility and conditions of the decentralized combustion of non-hazardous municipal waste. The analysis of the combustion properties of a mixture of wood chips and 20–30% of municipal solid waste showed an improvement in the operating parameters of the combustion process. Analysis also confirmed that the co-combustion of dirty fuels and biomass reduced the risk of releasing minerals and heavy metals from fuel into the natural environment. Approximately 55% of the heavy metals passed into the ash. The analysis of municipal solid waste and fuel mixtures containing municipal solid waste for polycyclic aromatic hydrocarbons showed the risk of increasing polycyclic aromatic hydrocarbon concentrations in flue gases.

A novel transdisciplinary paradigm for municipal solid waste to energy

2019 ◽  
Vol 233 ◽  
pp. 880-892 ◽  
Author(s):  
Mir Sayed Shah Danish ◽  
Tomonobu Senjyu ◽  
Hameedullah Zaheb ◽  
Najib Rahman Sabory ◽  
Abdul Matin Ibrahimi ◽  
...  
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Waste To Energy

Solid waste shape description and generation based on spherical harmonics and probability density function

2021 ◽  
pp. 0734242X2110450
Author(s):  
Yifeng Li ◽  
Xunpeng Qin ◽  
Zhenyuan Zhang ◽  
Huanyu Dong
Keyword(s):  
Probability Density Function ◽  
Solid Waste ◽  
Probability Density ◽  
Density Function ◽  
Spherical Harmonics ◽  
Morphological Data ◽  
Control Factor ◽  
Shape Description ◽  
Separation Processes ◽  
Waste Particles

Transport and separation processes of solid waste can only be modelled successfully with discrete element methods in case the shape of the particles can be described accurately. The existing techniques for morphological data acquisition, such as computed tomography, laser scanning technique, optical interferometer, stereo photography and structured light technique, are laborious and require a large amount of realistic solid waste samples. Therefore, there is a pressing need for an alternative method to describe the shape of solid waste particles and to generate multiple variations of particles with almost similar shapes. In this paper, a new method to describe solid waste particles is proposed that is frequency-based and uses spherical harmonics (SHs). Additionally, a new shape generation method is introduced that uses the shape description of a single particle to generate an array of related shapes based on a probability density function with a dimensionless control factor η. The newly proposed methods were successfully applied to describe the complex shapes of pieces of metal and plastic scrap. The shapes of these pieces of scrap can be described adequately with 15° of SH expansion and the overall divergence is within 0.1 mm. Five different values for η were tested, which generated shapes with the same distribution as the original particle. Rising levels of η cause the morphological variation of the generated particles to increase. These new methods improve the modelling of transportation and separation processes.

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