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At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Addition to the Lewis Chemical Equilibrium Program to allow computation from coal composition data

Changes made to the Coal Gasification Project are reported. The program was developed by equilibrium combustion in rocket engines. It can be applied directly to the entrained flow coal gasification process. The particular problem addressed is the reduction of the coal data into a form suitable to the program, since the manual process is involved and error prone. A similar problem in relating the normal output of the program to parameters meaningful to the coal gasification process is also addressed.

Sevigny, R.↗
NASA NTRS1982

Literature survey of properties of synfuels derived from coal

A literature survey of the properties of synfuels for ground-based turbine applications is presented. The four major concepts for converting coal into liquid fuels (solvent extraction, catalytic liquefaction, pyrolysis, and indirect liquefaction), and the most important concepts for coal gasification (fixed bed, fluidized bed, entrained flow, and underground gasification) are described. Upgrading processes for coal derived liquid fuels are also described. Data presented for liquid fuels derived from various processes, including H-coal, synthoil, solvent refined coal, COED, donor solvent, zinc chloride hydrocracking, co-steam, and flash pyrolysis. Typical composition, and property data is also presented for low and medium-BTU gases derived from the various coal gasification processes.

Flores, F.↗
NASA NTRS1983

IGCC performance comparison for variations in gasifier type and gas turbine firing temperature

Performance estimates were made for a series of integrated coal gasification combined cycle (IGCC) power systems using three generic types of coal gasification subsystems. The objectives of this study were (1) to provide a self consistent comparison of IGCC systems using different types of gasifiers and different oxidants and (2) to use this framework of cases to evaluate the effect of a gas turbine firing temperature and cooling approach an overall system efficiency. The basic IGCC systems considered included both air and oxygen blown versions of a fluidized bed gasifier, represented by the Westinghouse design, and an entrained bed gasifier, represented by the Texaco design. Also considered were systems using an oxygen blown, fixed bed gasifier, represented by the British Gas Corporation (BGC) slagging gasifier. All of these gasifiers were integrated with a combined cycle using a gas turbine firing temperature of 1700 K (2600 F) and a compressor pressure ratio of 16:1. Steam turbine throttle conditions were chosen to be 16.6 MPa/811 K (2400 psia/1000 F) with a single reheat to 810 K (1000 F). Some of these cases were modified to allow the evaluation of the effect of gas turbine firing temperature. Turbine firing temperatures from state of the art 1365 K (2000 F) to an advanced technology 1920 K (3000 F) were analyzed. A turbine cooling technology that maintains metal temperatures below acceptable limits was assumed for each level of firing temperature. System performance comparisons were made using three advanced turbine cooling technologies for the 1920 K (3000 F) firing temperature. The results indicate that the IGCC using the BGC gasifier had the highest net system efficiency (42.1 percent) of the five gasification cases considered.

Stochl, R. J.↗
NASA NTRS1986

Effects of droplet interactions on droplet transport at intermediate Reynolds numbers

Effects of droplet interactions on drag, evaporation, and combustion of a planar droplet array, oriented perpendicular to the approaching flow, are studied numerically. The three-dimensional Navier-Stokes equations, with variable thermophysical properties, are solved using finite-difference techniques. Parameters investigated include the droplet spacing, droplet Reynolds number, approaching stream oxygen concentration, and fuel type. Results are obtained for the Reynolds number range of 5 to 100, droplet spacing from 2 to 24 diameters, oxygen concentrations of 0.1 and 0.2, and methanol and n-butanol fuels. The calculations show that the gasification rates of interacting droplets decrease as the droplet spacings decrease. The reduction in gasification rates is significant only at small spacings and low Reynolds numbers. For the present array orientation, the effects of interactions on the gasification rates diminish rapidly for Reynolds numbers greater than 10 and spacings greater than 6 droplet diameters. The effects of adjacent droplets on drag are shown to be small.

Shuen, J. S.↗
NASA NTRS1987

Effects of droplet interactions on droplet transport at intermediate Reynolds numbers

Effects of droplet interactions on drag, evaporation, and combustion of a planar droplet array, oriented perpendicular to the approaching flow, are studied numerically. The three-dimensional Navier-Stokes equations, with variable thermophysical properties, are solved using finite-difference techniques. Parameters investigated include the droplet spacing, droplet Reynolds number, approaching stream oxygen concentration, and fuel type. Results are obtained for the Reynolds number range of 5 to 100, droplet spacings from 2 to 24 diameters, oxygen concentrations of 0.1 and 0.2, and methanol and n-butanol fuels. The calculations show that the gasification rates of interacting droplets decrease as the droplet spacings decrease. The reduction in gasification rates is significant only at small spacings and low Reynolds numbers. For the present array orientation, the effects of interactions on the gasification rates diminish rapidly for Reynolds numbers greater than 10 and spacings greater than 6 droplet diameters. The effects of adjacent droplets on drag are shown to be small.

Shuen, Jian-Shun↗
NASA NTRS1988

Systems Analysis Of Advanced Coal-Based Power Plants

Report presents appraisal of integrated coal-gasification/fuel-cell power plants. Based on study comparing fuel-cell technologies with each other and with coal-based alternatives and recommends most promising ones for research and development. Evaluates capital cost, cost of electricity, fuel consumption, and conformance with environmental standards. Analyzes sensitivity of cost of electricity to changes in fuel cost, to economic assumptions, and to level of technology. Recommends further evaluation of integrated coal-gasification/fuel-cell integrated coal-gasification/combined-cycle, and pulverized-coal-fired plants. Concludes with appendixes detailing plant-performance models, subsystem-performance parameters, performance goals, cost bases, plant-cost data sheets, and plant sensitivity to fuel-cell performance.

Ferrall, Joseph F.↗
NASA NTRS1987

The applicability of the catalytic wet-oxidation to CELSS

The wet oxidation catalysis of Au, Pd, Pt, Rh or Ru on a ceramic honeycomb carrier was traced in detail by 16 to 20 repetitive batch tests each. As a result, Pt or Pd on a honeycomb carrier was shown to catalyze complete nitrogen gasification as N2. Though the catalysts which realize both complete nitrogen gasification and complete oxidation could not be found, the Ru+Rh catalyst was found to be most promising. Ru honeycomb catalyzed both nitrification and nitrogen gasification.

Takahashi, Y.↗
NASA NTRS2015

A Burning Rate Emulator (BRE) for Study in Microgravity

A gas-fueled burner, the Burning Rate Emulator (BRE), is used to emulate condensed-phase fuel flames. The design has been validated to easily measure the burning behavior of condensed-phase fuels by igniting a controlled stream of gas fuel and diluent. Four properties, including the heat of combustion, the heat of gasification, the surface temperature, and the laminar smoke point, are assumed to be sufficient to define the steady burning rate of a condensed-phase fuel. The heat of gasification of the fuel is determined by measuring the heat flux and the fuel flow rate. Microgravity BRE tests in the NASA 5.2 s drop facility have examined the burning of pure methane and ethylene (pure and 50 in N2 balance). Fuel flow rates, chamber oxygen concentration and initial pressure have been varied. Two burner sizes, 25 and 50 mm respectively, are chosen to examine the nature of initial microgravity burning. The tests reveal bubble-like flames that increase within the 5.2s drop but the heat flux received from the flame appears to asymptotically approach steady state. Portions of the methane flames appear to locally detach and extinguish at center, while its shape remains fixed, but growing. The effective heat of gasification is computed from the final measured net heat flux and the fuel flow rate under the assumption of an achieved steady burning. Heat flux (or mass flux) and flame position are compared with stagnant layer burning theory. The analysis offers the prospect of more complete findings from future longer duration ISS experiments.

diffusion flames↗
DOE OSTI2025

Calculating the Effects of Solids Input and Removal as a Temperature Control in the Advanced Scale Up Reactor Experiment (ASURE) Facility at NETL Using Aspen

The Advanced Scale Up Reactor Experiment (ASURE) facility at NETL is being designed to be a fuel-flexible multi-purpose reactor that can be used for pyrolysis/gasification or evaluation of other high pressure “circulating fluidized bed” (CFB) chemical processes. The initial system design calculations for pyrolysis/gasification are presented in this work showing the expected performance of the ASURE facility when used as a biomass conversion reactor. Several other areas of application include gasification of any carbonaceous fuel including biomass, coal, plastics, and other waste materials. The reactor can therefore be used to produce SYNGAS of various compositions and hydrogen as well as other high value chemicals resulting from a typical tuned gasification process. This paper discusses an ASPEN model of the facility, focusing on the riser of the CFB reactor and the solids recirculation loop. The ASPEN model divides the riser into two sections. A bottom section which receives ash, char and sand which have been recirculated from a return loop. In this section an inert fluidization gas, (N2 or CO2), is introduced which acts as the primary mover of the solids through the system. The bottom section is equipped with a restricted air feed so that the recirculated char can be partially oxidized. This oxidation process along with the inventory of recirculating sand are used to effectively control the temperature in the following two chemical conversion sections of the reactor which are the pyrolysis zone followed by a tar cracking zone. Fresh fuel is added to the pyrolysis zone and undergoes drying and devolatilization. The products ash, char, volatile matter, and water vapor exit the pyrolysis zone and enter the reaction block for tar cracking. Steam and CO2 gasification reactions will be incorporated into the tar cracking zone, however at the design operating temperature, conversion from these reactions is expected to be essentially zero. The unit when completed in 2026 will test mixtures of biomass, plastics, and waste coal. This paper presents the basic ASPEN engineering design model for this project and provides preliminary sensitivity studies to determine how the various parts of the reactor will perform.

ASSURE↗
DOE OSTI2019

High-Octane Gasoline from Biomass: Experimental, Economic, and Environmental Assessment

Five economically-advantaged biomass feedstocks identified in the United States Department of Energy's 2016 Billion Ton Study were gasified and the syngas was reformed at the bench scale to study the feedstock price-performance relationship. The distribution of reformed syngas compositions, heating values, and yields were similar across the different feedstocks and blends thereof, which ranged from inexpensive residual wastes to more expensive and higher quality biomass, revealing that feedstock performance was mostly insensitive to its price. Custom blended feedstocks produced syngas with characteristics resembling linear combinations of syngas from single-component feedstocks, supporting the ability to customize and predict blended properties based on single-feedstock data. The experimental gasification data informed a techno-economic analysis of specific feedstock costs for producing high-octane gasoline, and the results showed that miscanthus and forest residues were the most cost-effective. A field-to-wheels life-cycle assessment of greenhouse gas emissions showed that forest residues was the most environmentally benign feedstock of those studied. from inexpensive residual wastes to more expensive and higher quality biomass, revealing that feedstock performance was mostly insensitive to its price. Custom blended feedstocks produced syngas with characteristics resembling linear combinations of syngas from single-component feedstocks, supporting the ability to customize and predict blended properties based on single-feedstock data. The experimental gasification data informed a techno-economic analysis of specific feedstock costs for producing high-octane gasoline, and the results showed that miscanthus and forest residues were the most cost-effective. A field-to-wheels life-cycle assessment of greenhouse gas emissions showed that forest residues was the most environmentally benign feedstock of those studied.

09 BIOMASS FUELS↗
DOE OSTI2018

Kemper County IGCC Final Public Design Report

The Kemper County IGCC plant is a lignite-fueled 2-on-1 Integrated Gasification Combined-Cycle (IGCC) facility incorporating the air-blown Transport Integrated Gasification (TRIG™) technology jointly developed by Southern Company; KBR; and the United States Department of Energy (DOE) at the Power Systems Development Facility (PSDF) in Wilsonville, Alabama. The plant is owned by Mississippi Power Company (MPC) and has a calculated nameplate capacity of 830 MW with a peak net output of 582 MW. As a result of advanced emissions-control equipment, the facility is designed to produce marketable products of ammonia (NH3), sulfuric acid (H 2 SO 4 ), and carbon dioxide (CO 2 ). The plant is designed to capture 65 percent of the carbon entering to sell for enhanced oil recovery (EOR), which makes the Kemper County plant’s carbon emissions comparable to those of a natural-gas-fired combined cycle power plant. This report describes the basic design and function of the plant as determined at the end of the Detailed Design phase of the project. The technical sections of the report were completed in October 2013, and the cost information was incorporated into Section 6.0 in March 2018.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Topical Report: Kemper County IGCC Final Public Design Report

The Kemper County IGCC plant is a lignite-fueled 2-on-1 Integrated Gasification Combined-Cycle (IGCC) facility incorporating the air-blown Transport Integrated Gasification (TRIG™) technology jointly developed by Southern Company; KBR; and the United States Department of Energy (DOE) at the Power Systems Development Facility (PSDF) in Wilsonville, Alabama. The plant is owned by Mississippi Power Company (MPC) and has a calculated nameplate capacity of 830 MW with a peak net output of 582 MW. As a result of advanced emissions-control equipment, the facility is designed to produce marketable products of ammonia (NH 3 ), sulfuric acid (H 2 SO 4 ), and carbon dioxide (CO 2 ). The plant is designed to capture 65 percent of the carbon entering to sell for enhanced oil recovery (EOR), which makes the Kemper County plant’s carbon emissions comparable to those of a natural-gas-fired combined cycle power plant. This report describes the basic design and function of the plant as determined at the end of the Detailed Design phase of the project. The technical sections of the report were completed in October 2013, and the cost information was incorporated into Section 6.0 in March 2018.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Topical Report: Kemper County IGCC Commissioning and Startup Report

The Kemper County IGCC plant was a lignite-fueled 2 x 1 Integrated Gasification Combined-Cycle (IGCC) facility that demonstrated the air-blown Transport Integrated Gasification (TRIG™) technology jointly developed by Southern Company, KBR, Inc. (KBR), and the U.S. Department of Energy (DOE) at the Power Systems Development Facility (PSDF) in Wilsonville, Ala. The plant is owned by Mississippi Power Company (MPC) and has a calculated nameplate capacity of 830 MW with a peak net output of 582 MW. As a result of advanced emissions control equipment, the facility is designed to produce marketable products of ammonia (NH 3 ), sulfuric acid (H 2 SO 4 ), and carbon dioxide (CO 2 ). The plant is designed to capture 65 percent of the carbon producing a CO 2 stream for use in enhanced oil recovery (EOR), making the plant carbon emissions comparable to those of a natural gas-fired combined cycle power plant. This report describes the unit commissioning activities from the end of construction through first coal operations to the gasifier. These activities include precommissioning planning, commissioning of major equipment, and operation of processes leading up to first coal feed.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2015

Chapter 8: Pyrolysis Mechanisms of Lignin Model Compounds Using a Heated Micro-Reactor

Lignin is an important component of biomass, and the decomposition of its thermal deconstruction products is important in pyrolysis and gasification. In this chapter, we investigate the unimolecular pyrolysis chemistry through the use of singly and doubly substituted benzene molecules that are model compounds representative of lignin and its primary pyrolysis products. These model compounds are decomposed in a heated micro-reactor, and the products, including radicals and unstable intermediates, are measured using photoionization mass spectrometry and matrix isolation infrared spectroscopy. We show that the unimolecular chemistry can yield insight into the initial decomposition of these species. At pyrolysis and gasification severities, singly substituted benzenes typically undergo bond scission and elimination reactions to form radicals. Some require radical-driven chain reactions. For doubly substituted benzenes, proximity effects of the substituents can change the reaction pathways.

09 BIOMASS FUELS↗
DOE OSTI2018

Reduction Enhancement Mechanisms of a Low-Grade Iron Ore–Coal Composite by NaCl

The reduction behavior of a low iron grade with high SiO{sub 2} content ore–coal composite was investigated in the temperature range of 1143 K to 1263 K (870 °C to 990 °C). Sodium chloride was chosen as an additive to promote this reduction process. The effect of the sodium chloride addition and its mechanism was also investigated. Results showed that the added sodium chloride could enhance the reduction of wustite to iron due to the decrease of fayalite, and a higher metallization ratio of reduced sample was obtained. Thermogravimetric–differential scanning calorimeter analysis showed that sodium chloride could greatly facilitate the gasification process of coal and, thus, provide sufficient carbon monoxide to the reduction process of iron oxides. Meanwhile, sodium chloride promoted the reduction process of iron ore pellets directly as the coal gasification effect was excluded. Microstructures of reduced sample revealed that sodium chloride broke the structure of ore and enhanced the growth of newly formed iron particles. As the ore–coal composite with mol (C/Fe = 1.4) and 3 mass pct sodium chloride addition was roasted at 1233 K (960 °C) for 55 minutes, a reduced sample with metallization ration of 74.45 pct could be obtained.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Relationship of Coke Reactivity and Critical Coke Properties

The gasification reactions of five metallurgical cokes were studied using a thermogravimetric analyzer at 1273 K and 1673 K in CO{sub 2}-CO-N{sub 2} gas mixture. The results show that these cokes showed different reactivities in the gasification reactions. Properties that potentially influence coke reactivity including ash content, catalytic index, surface area, and crystallite size were measured and correlated with reactivity. The results indicate that reactivity had a good correlation with ash content, catalytic index, and crystallite size. The effect of surface area on coke reactivity was marginal. Coke reactivity was positively affected by catalytic index but inversely affected by ash content. Although crystallite size inversely affected reactivity, the reaction rate at the initial stage was more predominantly influenced by the mineral matter. Therefore, the influence of surface area and crystallite size was overshadowed by the impact of ash content and catalytic index at the initial stage of reaction.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Influence of Iron Ore Addition on Metallurgical Reaction Behavior of Iron Coke Hot Briquette

Utilization of iron coke hot briquette (ICHB) has been considered to be one effective countermeasure to achieve low-carbon blast furnace. Before its actual application, a series of extensive fundamental investigations on the ICHB are required. In this study, the influence of iron ore addition on the metallurgical reaction behavior of ICHB made from carbonizing coal–iron ore composite agglomeration were investigated based on Chinese raw material conditions, and the corresponding mechanisms were revealed. The results show that the addition of iron ore concentrate leads to the degradation of the compressive strength and drum strength of ICHB, but they are maintained at a relatively high level. Furthermore, by increasing the addition ratio of iron ore from 0 to 20 pct, the density of ICHB is enhanced from 1413 to 1637 kg/m{sup 3}, and the porosity is increased from 8.03 to 12.84 pct, and the optical texture index (OTI) is reduced from 58.1 to 25.3. The phase composition of ICHB mainly consists of C, Fe, SiO{sub 2}, Fe{sub 3}O{sub 4}, and FeO after the addition of the iron ore concentrate. Moreover, the reactivity of ICHB is accelerated from 46.74 to 69.54 pct due to the catalytic effects of metallic iron and iron oxide, which worked as oxygen transfer carriers, while the post-reaction strength is reduced from 74.08 to 36.81 pct. In addition, the starting temperature of the ICHB gasification reaction is decreased remarkably from 919 °C to 839 °C. The activation energy (E{sub a}) for the gasification reaction under nonisothermal conditions is reduced from 312.78 to 249.83 kJ/mol, and the preexponential factor (A) shows a decreasing trend as well. Simultaneously, E{sub a} and A display the kinetic compensation effect and present a good linear relationship.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Reduction Mechanism of Iron Oxide Briquettes by Carbonaceous Materials Extracted from Blast Furnace Dust

The reducibility of carbonaceous powder extracted from blast furnace dust was investigated. In this study, pickling treatment was used for BF bag dust and BF gravitational dust to extract the carbonaceous material. The structural characteristics of carbonaceous material were studied by X-ray diffraction, scanning electron microscope, and energy-dispersive spectrometer. The reduction of ferric oxide and carbon gasification experiments were researched by thermogravimetry. The results show that the pickled raw coal gives the highest reducibility, which is followed by BF bag dust and BF gravitational dust. The reason for this is that the higher disordered crystalline structure leads to stronger gasification reactivity, and further results in stronger reduction reactivity. Based on the randomized nucleation model, the kinetic analysis shows that the activation energies for the reduction reaction of BF gravitational dust, BF bag dust, and raw coal after pickling are 300.14, 180.43, and 124.62 kJ mol{sup −1}, respectively.

36 MATERIALS SCIENCE↗