Dynamic Modeling of Steam-based Power Plants
Presented by NETL 2019 Annual Project Review Meeting for Crosscutting, Rare Earth Elements, Gasification and Transformative Power Generation, 04/19
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Presented by NETL 2019 Annual Project Review Meeting for Crosscutting, Rare Earth Elements, Gasification and Transformative Power Generation, 04/19
Presented by NETL at 2017 Project Review Meeting for Crosscutting Research, Gasification Systems, and Rare Earth Elements Research Portfolios, 03/17
Chemical looping with oxygen uncoupling (CLOU) is a variant of chemical looping combustion which uses as fluidized bed particles specific solid oxygen carriers which readily liberate gaseous oxygen (O2) in the fuel reactor. This enables much more efficient combustion of solid fuels such as coal than conventional chemical looping combustion, which relies on in situ gasification of char in to produce syngas that can react heterogeneously with the solid oxygen carrier. The CLOU process for coal is an especially interesting application of fluidized bed technology since several types of reactions take place within the reactors. For copper-based oxygen carrier particles, the copper cycles between cuprous and cupric oxide (Cu2O + ½ O2 ↔ 2 CuO). Volatiles released from coal during pyrolysis may react with oxidized copper or with released oxygen gas. Char reacts primarily with released oxygen. Balancing oxygen supply to the fuel reactor, heat generation and temperatures and global and internal circulation rates is a challenge. The University of Utah has been researching CLOU technology for 10 years, studying fundamental reaction kinetics for copper-based CLOU oxygen carriers, performing lab- and bench-scale experiments in single and dual fluidized beds, and developing reactor models through computational fluid dynamic modeling using Barracuda VR™. Recently the university began testing a 200 kWth dual circulating fluidized bed process development unit (PDU) for processing coal. The design process for that reactor, reactor simulations, operational experience and practical challenges of the PDU system are presented.
Chemical looping with oxygen uncoupling (CLOU) is a variant of chemical looping combustion that involves spontaneous release of gaseous oxygen in the fuel reactor, which enables efficient combustion of solid fuel char. The University of Utah has constructed a 200 kW pilot-scale chemical looping process development unit (PDU) consisting of two fluidized beds. The CLOU oxygen carrier uses copper as the active metal, cycling between cupric (CuO) and cuprous (Cu2O) oxides. As an aid for design, troubleshooting and evaluation of the pilot system, a CFD model has been developed using CPFD Software’s Barracuda VR software. The 3D model includes both reactors, as well as loop seals and cyclone separators. Mechanisms describing CLOU reaction kinetics for cuprous oxide oxidation in the air reactor and cupric oxide reduction in the fuel reactor were adapted from previously reported experimental work. Coal char kinetics were based on the carbon-hydrogen-nitrogen-oxygen-sulfur, CHNOS, method. Submodels for devolatilization, gasification, and homogenous gas-phase reactions used preexisting relationships in the literature. Three different simulations were performed, analyzing the influence of particle properties (a base carrier and an alternate carrier referred to as cariact) and coal feeding rate (100kW, 200kW). Increased coal feeding rate caused significant increase in cuprious oxide oxidation in the air reactor as well as higher temperature. The alternate carrier predicted CO2 capture below 90%, in contrast to the other cases.
Presented by NETL at 2019 Annual Project Review Meeting for Crosscutting, Rare Earth Elements, Gasification and Transformative Power Generation, 04/19
Presented by NETL at 2019 Annual Project Review Meeting for Crosscutting, Rare Earth Elements, Gasification and Transformative Power Generation, 04/19
Presented by NETL at 2019 Annual Project Review Meeting for Crosscutting, Rare Earth Elements, Gasification and Transformative Power Generation, 04/19
Idaho National Laboratory is developing a polymer membrane designed to concentrate oxygen from air to assist in cleaner coal combustion and other gasification processes. These membranes were formed by adding nanodiamond particles to enhance their transport properties. This study focuses on the thermomechanical analysis (TMA) of these membranes to probe the behavior between the nanodiamond particles and the polymer.
Global interest for using terrestrial biomass as an energy source has been increasing recently due to potentially significant socio-economic and environmental benefits relative to fossil energy. Thermochemical biomass processes converting biomass to fuels are relatively well developed, e.g. for direct combustion, gasification, and pyrolysis. However, critical problems often arise when attempting to feed biomass into commercial-scale reactors continuously and without interruption. Biomass particles, whether derived from woody or agricultural feedstock, vary greatly in size, shape, density, and moisture content. High cohesiveness, low bulk density, and poor material flow characteristics often prevent continuous feeding due to bridging, rat-hole formation, blockage, and seal failures. Among all different types of feeders utilized to feed biomass into reactors, screw feeding has received significant attention in recent years. Screw feeders are fuel-specific and require careful design to be reliable, efficient, and economical, especially for reactors operating at elevated pressures. In order to mimic the flow properties of compressed biomass inside a compression-screw feeder, rheological properties of three types of compressed lignocellulosic biomass were investigated using a co-rotating twin screw microcompounder. Experiments were conducted to find the impact of moisture content, particle size and type, and screw speed on rheological properties of forest residual particles as well as sawdust. Increasing moisture from 10 to 50% reduced the apparent viscosity of the compressed biomass. Also, higher screw speeds (10 to 90 rpm) led to a lower relative viscosity. At elevated screw speeds, significant temperature differences were measured between the initial and final states, which should be accounted for in equipment design and operation.
The present disclosure relates to apparatuses and methods that are useful for one or more aspects of a power production plant. More particularly, the disclosure relates to combustor apparatuses and methods for a combustor adapted to utilize different fuel mixtures derived from gasification of a solid fuel. Combustion of the different fuel mixtures within the combustor can be facilitated by arranging elements of the combustor controlled so that a defined set of combustion characteristics remains substantially constant across a range of different fuel mixtures.
Presented by NETL at 2019 Annual Project Review Meeting for Crosscutting, Rare Earth Elements, Gasification and Transformative Power Generation, 04/19
Consistent and reliable preprocessing, conveyance, and reactor in-feed systems, particularly for low-cost waste feedstocks, remains a major technical challenge for the emerging Bioeconomy. By identifying critical biomass attributes and connecting them to flow and conversion behavior, science-driven system designs can address these often-overlooked solids handling challenges. The Wonderful Company (TWC) is the world's largest almond and pistachio grower, generating 250,000 dry tons/year of waste material including hulls, shells, and wood (>5 million tons/year industry wide in the U.S.). This project seeks to turn this environmental and economic liability into a sustainable and profitable resource, targeting conversion via gasification to syngas for electricity and bio-char, by addressing related material handling and feeding challenges. Based on optimized preprocessing strategies, bulk material flow, and thermal conversion properties, an overall system design will be developed. The methodology will be tested with FCIC's benchmark loblolly pine residues, to demonstrate the robustness of the overall approach and provide insight and guidance for future systems. The project will culminate in extended field trials to demonstrate an improved continuous feeding system with a commercial biomass-to-electricity gasifier vendor, and an economic analysis demonstrating a reduction in electricity production costs by maximizing on-stream time while minimizing preprocessing and CapEx costs.
Coal ash slag as a waste by-product, is generated from commercial processes that include gasification facilities, power plants, and steelmaking industries. Some is recycled into construction materials, insulation fibers, and used as a soil neutralizer, but the majority is still discarded. Coal ash slag exhibit trace amounts of critical materials including rare earth elements (REEs). An economically viable extraction of REEs from the coal ash would lower the production costs, addressing the availability and environmental concerns. In nature, most REEs exist as phosphate such as monazite but its synthetic evolution in coal ash slag has never been reported. In industrial processes, P may originate from coal, additives, and/or refractory liners. REEs may be extracted by first concentrating REEs into phosphates, sulphide, or fluorides [1], or carbonates [2]. In this work, P-enriched coal ash slag bearing REEs was first melted above 1600 °C, then crystallization behaviors in the melt during controlled cooling was studied. REE phosphate coprecipitated with mullite and hematite with mullite being the first crystal to form on cooling. The REEs were rejected from the molten slag, mullite, and hematite, and tended to segregate only to the phosphate phase with REE concentration as high as 58 wt.% in the structure.
Coal ash slag as a waste by-product, is generated from commercial processes that include gasification facilities, power plants, and steelmaking industries. Some is recycled into construction materials, insulation fibers, and used as a soil neutralizer, but the majority is still discarded. Coal ash slag exhibit trace amounts of critical materials including rare earth elements (REEs). An economically viable extraction of REEs from the coal ash would lower the production costs, addressing the availability and environmental concerns. In nature, most REEs exist as phosphate such as monazite but its synthetic evolution in coal ash slag has never been reported. In industrial processes, P may originate from coal, additives, and/or refractory liners. REEs may be extracted by first concentrating REEs into phosphates, sulphide, or fluorides [1], or carbonates [2]. In this work, P-enriched coal ash slag bearing REEs was first melted above 1600 °C, then crystallization behaviors in the melt during controlled cooling was studied. REE phosphate coprecipitated with mullite and hematite with mullite being the first crystal to form on cooling. The REEs were rejected from the molten slag, mullite, and hematite, and tended to segregate only to the phosphate phase with REE concentration as high as 58 wt.% in the structure.
Global demand for methanol as both a chemical precursor and a fuel additive is rising. At the same time, numerous sustainable methanol production pathways are under development which, if commercialized, could present significant environmental benefits over traditional methanol synthesis pathways. There is a need to harmonize the analyses of sustainable pathways using a consistent techno-economic approach to evaluate the potential for commercialization of various pathways. This analysis considers economic and environmental factors critical to market acceptance of three sustainable pathways versus a commercial baseline. We suggest that biomass gasification to methanol represents a near-term viable pathway with high technology readiness level and commercially competitive market price. However, long-term solutions should consider CO2 electrolysis pathways which offer further improvements in sustainability metrics to support global decarbonization efforts.
This project is developing the centerpiece technology for a market-responsive, integrated biorefinery concept based on the conversion of renewable C1 intermediates (e.g., syngas, CO2, methanol) to a suite of fuels and co-products with improved carbon efficiency, reduced capital expense, and control of the product distribution to meet market demand. Advanced upgrading technologies of syngas are critically needed for the successful commercialization of fuel production at a scale relevant for biomass gasification. Research tasks within this project leverage complementary catalyst and process design for the conversion of CO2-rich syngas (15-20% CO2 in syngas) to achieve high carbon yields of gasoline and jet fuels as the major products. The conversion pathways generate high quality fuels (e.g., high octane gasoline with low aromatics, desirable jet-range hydrocarbons), and potential to achieve favorable cost targets by 2022. Research progress is compared against the Mobil Olefin to Gasoline and Distillate (MOGD) process, which also offers control over the gasoline and distillate products, as an industrial benchmark. The pathway for direct conversion of CO2-rich syngas to hydrocarbon fuels seeks to exceed the carbon efficiency of biomass-sourced MOGD (31.8%). Recent catalyst and process development achievements are highlighted by improvements in carbon-selectivity to fuels and carbon yields, along with evidence of incorporation of carbon from CO2 into the hydrocarbon products.
The call to reduce global CO2 emissions is at the forefront of research and development in the transportation and petrochemical industries. A potential solution which intersects both sectors is the adoption and commercialization of more sustainable technologies for methanol production. Currently, methanol is gaining popularity as a possible fuel additive, and as a polymer precursor via established methanol-to-olefins routes which are increasing in capacity and utilization, putting methanol in the spotlight and global methanol production on the rise. At the same time, experimental and computational studies have surged, illuminating a wide array of novel process designs to introduce sustainable methanol into the market. However, with numerous competing pathways identified across a variety of fossil and non-fossil feedstocks, there is a need to harmonize the analyses of these pathways using a consistent techno-economic approach and compare them to current commercial pathways to better understand the benefits or limitations inherent to each technology. In this work we conduct a consistent comparative analysis of three sustainable methanol synthesis pathways versus a commercial baseline, with biomass, CO2, and natural gas as the carbon sources. The three sustainable pathways of interest are biomass gasification to syngas with subsequent catalytic conversion of syngas to methanol, indirect conversion of CO2 to syngas via electrolysis with subsequent catalytic conversion of syngas to methanol, and direct conversion of CO2 to methanol via electrolysis. To elucidate the challenges and opportunities in the path to commercialization of each sustainable pathway, we investigate five key process metrics: production cost, carbon efficiency, carbon intensity, energy efficiency, and technology readiness level (TRL).
This document provides a comparison of several food waste utilization options: landfill gas capture, anaerobic digestion, and composting, across various metrics. These options are the most prevalent pathways for energy and resource recovery. Other options, not considered here, include food donation, animal feed, incineration, and gasification. The table below describes the differences or similarities between these processes and provides information about products, the number of current projects in the United States, capital and operation and maintenance (O&M) costs, job development potential, emissions, and incentives associated with each pathway, as well as other parameters, such as level of complexity, land requirement, and revenue type. Sources for the data in the table are listed in the references at the end of the document.