Gasification Research Articles

Current and emerging waste-to-energy technologies: A comparative study with multi-criteria decision analysis

Current and emerging waste-to-energy technologies: A comparative study with multi-criteria decision analysis

A comparative ammonia recovery study of solid wastes discharged from rice husk gasifi cation and combustion plants

A comparative ammonia recovery study of solid wastes discharged from rice husk gasifi cation and combustion plants

Potential of integrating Solid Oxide Fuel Cell based on biomass in power generation in Malaysia: A feasibility study

Although many initiatives have been launched to achieve the ambitious Net Zero 2050 target, Malaysia is still struggling to control carbon emissions, particularly from electricity and heat generation. Fortunately, the potential to generate electricity from biomass in Malaysia reduces reliance on fossil fuels for power generation. Combining biomass gasification with a solid oxide fuel cell (SOFC) promises sustainable and more efficient performance than the traditional approach. To ensure optimal operation, the biomass-derived fuel should be compatible with the gasification system. A numerical simulation was carried out to gain insight into the feasibility of integrating hybrid gasification (GT) with SOFC based on selected biomass-derived fuels (i) palm oil mill effluent (POME) and (ii) refuse-derived fuel. A detailed anode-based planar SOFC model is developed and adopted into a gasification system that operates with an ideal gas under steady-state conditions. The other components considered in this study are a recuperator, combustor, and high-pressure turbine. A comprehensive energy balance for each stage was prepared to determine the overall performance of the system with higher accuracy. A detailed analysis shows that POME gave better results owing to its higher calorific value, resulting in higher thermal energy production. Reducing the required fuel flow rate has a positive effect on the overall performance compared with increasing the injected air flow rate. Furthermore, reducing the fuel flow rate tends to increase the combined efficiency. The study concludes that the fuel flow rate has a significant impact on the performance of the SOFC-GT hybrid system, particularly on combined efficiency and overall performance.

Thermodynamic evaluation on chemical looping conversion of Cd- and Zn-contained phytoremediation plant with different CaO pathways

Thermodynamic evaluation on chemical looping conversion of Cd- and Zn-contained phytoremediation plant with different CaO pathways

Simultaneous Greenhouse Gas Reduction and Cost Optimisation of Municipal Solid Waste Management System in Malaysia

In Malaysia, the rapid growth of population and new consumption trends are causing an increase in municipal solid waste (MSW) generation rate. To make matters worse, the current MSW handling practices in Malaysia are mostly dumping in open landfills with no proper landfill gas collection and energy recovery system, producing greenhouse gas (GHG) emissions to the atmosphere. This handling process undoubtedly causes climate change and is economically unfavourable. In this study, a multi-objective mixed-integer linear programming (MILP) approach was simulated using General Algebraic Modeling System (GAMS) to determine the optimum allocation of MSW on different disposal and treatment facilities (DTF), including sanitary landfills, incineration, recycling, anaerobic digestion, composting, and plasma arc gasification. The mathematical model utilised the augmented e-constraint method to minimise the capital and operational cost, maximise the value of final products, and minimise GHG emissions simultaneously. As compared to the current MSW management situation in Malaysia (total cost: 7.24 M MYR/d, net GHG emissions: 70,465 t CO2-eq/d), the least cost Pareto solution (total cost: 7.23 M MYR/d, net GHG emissions: 24,630 t CO2-eq/d) shows a more than 65 % reduction in GHG emissions without incurring any additional cost. The 9th,10th, and 11th Pareto optimal solutions would be able to achieve the national recycling target of 22 % by 2020 as promulgated by the Malaysia Government. It is hoped that this study can provide guidance on the best allocation of MSW on DTF for decision-makers to plan and design the best in class solution for MSW management not only in Malaysia but also regions that face a similar MSW disposal dilemma.

Spatiotemporal statistical characteristics of multiphase flow behaviors in fuel reactor for separated-gasification chemical looping combustion of solid fuel

Spatiotemporal statistical characteristics of multiphase flow behaviors in fuel reactor for separated-gasification chemical looping combustion of solid fuel

Valorization of sugarcane bagasse waste for fly ash production and application as an adsorbent

In this study, fly ash (FA) was derived from extracted sugarcane bagasse solid waste (ESBSW) and chemically modified to apply as an adsorbent. Impact of activated FA particles (200 and 250 µm) and adsorbent bed height (4, 6 and 8 mm) on pollutant removal efficiency was evaluated. ESBSW was combusted in laboratory-scale gasifier operated at 1000 °C for 1 h. The black solid residue was sieved to obtain the desired particle size followed by activation with 10% and 15% sulfuric acid. Wastewater samples collected from the drainage site of BUITEMS were analyzed and treated with the prepared adsorbent. ESBSW-FA 250 activated with 15% H 2 SO 4 with 8 mm bed height showed high efficiency. Where, 94.37%, 95.1% and 63.5% removal efficiency of chemical oxygen demand (COD), total solids (TS) and turbidity was attained, respectively. The pH of treated water was neutral. ESBSW has shown great potential to be used as a precursor for valuable byproducts. It's recycling for adsorbent preparation will economically and environmentally benefit the sugar industry.

Fixed-bed gasification and pyrolysis of organic fraction of MSW blended with coal samples

Buildup of vast quantities of municipal solid waste (MSW) including refuse derived fuel, organic fraction around the urban areas has negative environmental consequences. Gasification and pyrolysis of municipal solid waste could be an attractive option to utilize or convert to a valuable product. This study investigates the thermochemical properties of refuse derived fuel (RDF), organic fraction of MSW (Org MSW) and coal samples. Along with proximate and elemental analysis, calorific values were provided for RDF, MSW organic fraction, and coal samples. This followed by the thermogravimetric analysis of the same samples. In addition, Org MSW MSW and coal samples were blended in a proportion of 0.5/0.5 and 0.25/0.75 and then thermally treated in horizontal tube furnace both under air and inert gases to investigate the pyrolysis and gasification processes. TGA tests revealed that volatile content from Org MSW and RDF begin to be emitted at temperatures above 180-200 °C. Org MSW and RDF lose all their volatile contents at 500 °C and 700 °C. Pyrolysis experiments revealed that below 500 °C mostly tars are formed from Org MSW. Organic MSW and coal 0.5/0.5 blends yielded higher methane concentrations than coal or MSW alone, reaching 35-37 % at 800 °C. It could be concluded that both fixed bed and thermogravimetric method analysis have provided a good result to investigate the gasification and pyrolysis processes.

Energy from Biomass: combustion and gasification

Energy from Biomass: combustion and gasification

Analysis of Fundamental Properties and Durability of Concrete Using Coal Gasification Slag as a Combined Aggregate

Analysis of Fundamental Properties and Durability of Concrete Using Coal Gasification Slag as a Combined Aggregate

Techno-economic Feasibility of Thermochemical Conversion Pathways for Regional Agricultural Waste Biomass

This study examines four prominent thermochemical conversion technologies such as slow pyrolysis (SP), fast pyrolysis (FP), gasification (GA) and hydrothermal liquefaction (HTL), for treating poultry litter in New York State (NYS). Nine cases involving various combinations of the four technologies and different downstream processing options such as bio-oil upgrading, Fischer-Tropsch conversion and combined heat and power generation are chosen based on the product composition and distribution. High-fidelity process simulations for each technological platform are performed to derive the mass and energy balance information. Calculations and breakdown of the equipment costs, capital costs, operating and maintenance costs and utilities are provided and compared extensively for each of the nine cases. The economic performance is further analyzed by calculating and comparing the resultant net present values (NPV), ranging from $10 M to $170 M (SP), $89 M to $314.5 M (FP), $28 M to $196 M (HTL) and $25 M to $234 M (GA). The greenhouse gas emission inventories are also compiled to understand the corresponding impacts of different downstream processing choices (ranging from 217 to 494.5 kg CO2-eq/t feedstock with both the pyrolysis technologies outperforming the others in most cases) and to highlight the trade-off with economic performance. Through sensitivity analysis, the influential factors requiring further investigation are identified and it is found that plant capacity and bio-oil yield are the most important parameters for the fast pyrolysis systems, biochar price for SP is the single most important parameter.

Kinetic model of steam reforming for heavy tar decomposition in biomass gasification

Gasification technology as a feasible clean and efficient utilization technology has been developed to convert the low-grade energy resources like biomass into high value syngas.The generation of syngas is often accompanied by tar formation, which causes blockage in the downstream processing as tar condenses. The elimination of naphthalene and pyrene as heavy tar model compounds by steam reforming was studied by experiments in a horizontal tube reactor and simulation with CHEMKIN. A good agreement between the measured and calculated results of light gas products and soot was obsvered, and one can found that the reactivity of naphthalene is higher than that of pyrene in the presnece of steam and most of carbon of both hydrocarbons convert into soot instead of light gaseous products. The reaction pathways of steam reforming were developed by sensitivity analysis and rate of production. Benzene and naphthalene, represented as precursor of light gas product, are dominated intermediate components of naphthalene and pyrene. The simplified reaction schemes including the reaction pathway as well as the associated kinetics were derived by CHEMKIN.

Energy and Carbon Emission Optimisation of Coal to Syngas Process

Coal gasification to syngas is a common technique for coal utilization and consumes large amount of energy. The design and operation of gasifier, washing column and heat exchangers affect the energy consumption and carbon emission of the whole system. In this work, a coal to syngas process is simulated by Aspen Plus software. Based on the simulation results, the integration among the coal gasification, shift process and rectisol process are analysed; the heat exchanger network (HEN) is optimised to minimize the energy consumption and the carbon dioxide emission. The utility consumption is reduced by 17.4 %, and the emission of CO2 is reduced by 5.1 %.

Economic Analysis of Syngas Production by Coupling Coal Gasification Wastewater Treatment and Solid Oxide Cell System

Coal is the main energy source in China, and coal chemistry wastewater treatment has always been a research hotspot. For the large amount of concentrated organic wastewater, high cost caused by complex treatment process is the key issue. In this paper, the fixed bed Lurgi gasifier wastewater coupled with solid oxide cells (SOCs) system is employed for its treatment. Based on Aspen Plus software, the purified methane from marsh gas is sent to solid oxide fuel cell (SOFC) for electricity generation. While carbon dioxide separated from biogas purification and acid gas removal enters solid oxide electrolysis cell (SOEC) to produce syngas by co-electrolysis with steam.The simulation results show that the efficiency of SOFC is 48.5 %. The generated electric energy can be used for auxiliary equipment in wastewater treatment and SOEC to produce syngas, recycling of carbon dioxide. SOEC with wind power of 12.84 MW is enough to treat the waste gas generated by the 1,100 t/h Lurgi gasification wastewater treatment process. Economically, the cost of producing syngas, with high purity and fewer contaminant contents, is about 0.126 $/Nm3. It can be used to produce various chemicals, so as to further improve the economic benefit of wastewater treatment.

A Novel Design of Methyl Methacrylate Synthesis Process with Low CO2 Emission

Methyl methacrylate (MMA) is an important raw material for synthesising polymethyl methacrylate, plastic modifier, and surface coating. In this paper, an optimum “energy saving and low emission” process is proposed for MMA production. MMA is synthesised from ethylene and synthetic gas generated from coal chemical looping gasification (CLG), which can largely reduce CO2 emission. Firstly, the reaction mechanism of coal CLG is investigated using molecular dynamics simulation. Secondly, to verify the feasibility of the process, the steady-state simulation of MMA production process is carried out by Aspen Plus. Finally, based on the steady-state simulation results, one control scheme is verified with Aspen Dynamics to strictly control the purity of MMA.

Three-dimensional modelling of the multiphase hydrodynamics in a separated-gasification chemical looping combustion unit during full-loop operation

Three-dimensional modelling of the multiphase hydrodynamics in a separated-gasification chemical looping combustion unit during full-loop operation

Optimization of the Efficiency in a Syngas Powered Si Engine Through Numerical Studies Related to the Geometry of the Combustion Chamber

The combustion process occurring in an alternative Spark Ignition (SI) engine powered with bio-syngas from biomass gasification was previously studied by authors through the development of two different numerical models: a 0-1D model developed in the GT-Suite® environment, aimed at gaining a first look upon the main features of the heat release by the syngas and engine performances; a 3D Computational Fluid Dynamics (CFD) model developed within the AVL FireTM software reproducing the engine combustion cycle within a Reynolds Averaged Navier Stokes (RANS) schematization and employing a detailed chemical reaction mechanism to highlight the interaction between the fluid dynamics and the kinetics of the specific biofuel oxidation chain. The numerical results were validated with respect to experimental measurements in a baseline condition, where the presence of a relatively high amount of CO in the exhaust gases was noticed as related to an engine low combustion efficiency, mainly due to the peripheral spark plug position that determines the persistence of residual gases on the opposite side of the combustion chamber wall.The proposed work presents a numerical analysis made through the developed models on the effects of proper changes in the spark plug position. A multi-objective optimization problem is conducted also by varying the Start of Spark (SOS) and the mixture air-to-fuel ratio with the aim of reducing the engine environmental impact without affecting its performances. A centrally mounted spark, along with a correct calibration of the SOS and mixture ratio, allows a reduction of more than 90% of CO emission with respect to the baseline condition without penalizing the engine brake power and efficiency.

Experimental Study on Sugarcane Bagasse Pyrolysis in a Hermochemical Processes Pilot Plant

This paper investigates the sugarcane bagasse pyrolysis for bio-oil and biochar production in a pilot plant that was designed to perform the gasification process. After some modifications of changing the temperature of fluidized bed reactor and the catalytic reforming reactor, the fast pyrolysis process was performed at 500–600 °C using a fluidized bed reactor (air flow rate: 20–70 L.min-1) under atmospheric pressure, with sugarcane bagasse feeding (2–3.5 kg.h-1) with particles size less than 1.18 mm. Fluidization tests were performed with air feed (oxidative pyrolysis), to guarantee the fluidization is occurring, finding that the minimum fluidization rate was 22 L.min-1 (minimum velocity of gas: 6.3 cm.s-1). The residence time was 7 seconds (ratio between empty reactor volume by fluidizing gas flow). The highest bio-oil yield of 7.43 wt. % was obtained at 500 °C, with a bagasse flow rate of 3.5 kg.h-1 and 25.93 L.min-1 of air flow rate, and this low yield can be explained by the inefficient heat exchanger used. On the other hand, biochar yield achieved 35.88 wt. % using a temperature of 570 °C, 3.1 kg.h-1 of bagasse flow rate, and 28.26 L.min-1 of air flow rate. Considering this pilot plant has never operated in a pyrolysis mode, these results demonstrate that pyrolysis can be applied to this pilot plant, being versatile for different types of processes with a great potential for biochar and bio-oil production besides the high gas production.

Biomass combustion: Environmental impact of various precombustion processes

Biomass combustion: Environmental impact of various precombustion processes

Determination of a Complete Conversion Model for Gasification of Lignite Char

The conversion of solid fuels via gasification is a viable method to produce valuable fuels and chemicals or electricity while also offering the option of carbon capture. Fluidized bed gasifiers are most suitable for abundantly available low-rank coal. The design of these gasifiers requires well-developed kinetic models of gasification. Numerous studies deal with single aspects of char gasification, like influence of gas compositions or pre-treatment. Nevertheless, no unified theory for the gasification mechanisms exists that is able to explain the reaction rate over the full range of possible temperatures, gas compositions, carbon conversion, etc. This study aims to demonstrate a rigorous methodology to provide a complete char gasification model for all conditions in a fluidized bed gasifier for one specific fuel. The non-isothermal thermogravimetric method was applied to steam and CO2 gasification from 500 °C to 1100 °C. The inhibiting effect of product gases H2 and CO was taken into account. All measurements were evaluated for their accuracy with the Allan variance. Two reaction models (i.e., Arrhenius and Langmuir–Hinshelwood) and four conversion models (i.e., volumetric model, grain model, random pore model and Johnson model) were fitted to the measurement results and assessed depending on their coefficient of determination. The results for the chosen char show that the Langmuir–Hinshelwood reaction model together with the Johnson conversion model is most suitable to describe the char conversion for both steam and CO2 gasification of the tested lignite. The coefficient of determination is 98% and 95%, respectively.