Download or read book Chemical and physical stability of refractories for use in coal gasification written by University of Missouri--Rolla. Ceramic Engineering Department and published by . This book was released on 1977 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification written by United States. Department of Energy and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical and physical stability of refractories for use in coal gasification written by University of Missouri--Rolla. Ceramic Engineering Department and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification First Annual Progress Report May 1 1976 April 30 1977 written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This project commenced on 1 May 1976 with the objective of (a) achieving an understanding of the general types of chemical reactions occurring in refractories when exposed to conditions representative of those at the cold face of the refractory lining in coal gasification vessels, (b) assessing the relative importance of these reactions to those physical/chemical properties required for long-service life, and (c) identifying those refractory systems providing optimum service performance, particularly in regard to the bond phases. The basic aim of the investigation is to establish the corrosion resistance of refractories, especially the bond phases, to high pressure/temperature gas and liquid environments encountered in coal gasification. This annual report summarizes all of the data obtained and analyzed during 1 May 1976 to 30 April 1977. Portions of the tables in this report are incomplete since analysis of the exposure test results is still in progress.
Download or read book Chemical and physical stability of refractories for use in coal gasification written by Syed F. Rahman and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification Sixteenth Quarterly Progress Report February 1 1980 April 30 1980 written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments on the corrosion resistance and thermal expansion of refractories for coal gasification plants are reported. The properties of a given castable were basically similar after exposure, regardless of whether the specimens had been immersed in liquid or in contact with saturated vapor. The thermal expansion of several refractories over the temperature range of 20/sup 0/C to 950/sup 0/C, and exposed to the DOE atmosphere of containing 1 vol % H/sub 2/S at 1000 psi, is reported. Some samples were cycled from 465/sup 0/C to 1000/sup 0/C. (LTN).
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification Final Report May 1 1976 July 31 1980 written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The dimensional stability, density, porosity, flexural strength and thermal expansion of eighteen cement-bonded, dense and lightweight refractory castables and three phosphate bonded refractories were determined before and after exposure to conditions chosen to simulate those at the cold face (approx. 250/sup 0/C) of a refractory lining in a coal gasification vessel. Chemical reactions occurring in the refractories during exposure were determined by XRD, DTA/TGA and SEM and correlated with the above properties. The variables investigated were: (1) exposure time, 60 days maximum; (2) temperature, up to 538/sup 0/C; (3) pressure, 6.9 MPa maximum; (4) gas composition, particularly CO/steam ratio (0.1, 1, and 3.0) and presence of 1 vol % H/sub 2/S; (5) degree of saturation and (6) liquid versus vapor contact. The degree of saturation of the test atmosphere was the single most important factor affecting the properties after exposure. In dry atmospheres, the properties were close to those for specimens heated to the same temperature in air. In 100% saturated atmospheres, however, the dense cement bonded castables typically had a flexural strength two to three times higher than that before exposure and a significantly lower porosity. Conversely, the flexural strength of the phosphate bonded refractories was only 1/2 to 1/5 of that before exposure. The exposure time was not particularly important since the chemical reactions occurring during exposure and responsible for the changes in properties, are relatively rapid and appear to be nearing completion within a few days, less than or equal to 10. All of the refractories were structurally intact after the 60-day maximum exposure to both dry or saturated conditions. The principal chemical reactions in the cement bonded castables were between the cement bond phases and steam, CO, and CO/sub 2.
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification First Quarterly Progress Report 1 May 1976 31 July 1976 written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Activities in a program concerned with establishing the corrosion resistance of refractories to environments encountered in coal gasification are summarized. Materials being investigated are calcium aluminate cement and phosphate bonded alumina refractories. The major effort during the report period has been devoted to the modification, construction, and proof testing of the exposure test system, selection and acquisition of raw materials and commercial products, and development of experimental procedures. (JRD).
Download or read book Chemical and physical stability of refractories for use in coal gasification written by Syed F. Rahman and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification written by Syed F. Rahman and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Physical Stability of Refractories for Use in Coal Gasification written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification Ninth Quarterly Progress Report 1 May 1978 31 July 1978 written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Activities are reported in a program to establish the corrosion resistance of refractories, especially the bond phases, to those high pressure/temperature gases and liquids typically present in coal gasification vessels. During this quarter, preparation and pre-exposure characterization of refractory and cement samples for an exposure test were completed. This test commenced on 7 July 1978 and the first two boehmite formation/decomposition cycles have been completed. Seven commercial and laboratory prepared cement-bonded castables and three calcium aluminate cements are being investigated currently. These materials and their chemical compositions are listed. In general, the insulating castables show smaller changes in modulus of rupture (MOR) than the dense castables after exposure to the cyclic conditions. The MOR of Cerlite 75 and VSL-50 remain nearly constant, with only Litecast 60-25 showing any major change in MOR and that is an increase. This behavior is consistent with results from earlier exposures in the DOE and CO/steam atmosphere.
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification Quarterly Progress Report November 1 1977 January 31 1978 written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: General conclusions are based on the results obtained to date in the three CO/H/sub 2/O and 60 day exposure tests: (1) Large weight losses were observed for refractory samples immersed in water in the CO/H/sub 2/O = 3 test compared to CO/H/sub 2/O = 0.1 or 1 tests and, in general, increased with increasing CO/H/sub 2/O ratio. This weight loss is most likely due to the dissolution of CaO from the refractories. Chemical analysis is in progress. (2) The weight changes in the unsaturated (1000/sup 0/F) and saturated (532, 466, and 400/sup 0/F) vapors were basically the same in the three CO/H/sub 2/O tests. (3) With a few exceptions high and intermediate alumina refractories generally had the lowest porosity when exposed to the saturated atmosphere (vapor or liquid) at CO/H/sub 2/O = 0.1 and the highest when immersed in water at CO/H/sub 2/O = 3.0. (4) Porosities of high and intermediate alumina refractories in unsaturated atmospheres and insulating castables in saturated and unsaturated atmospheres generally remained nearly constant for CO/H/sub 2/O ratios of 0.1 to 3. (5) The effect of saturation on the flexural strength of high and intermediate alumina was significant in all three CO/H/sub 2/O tests and, in general, the flexural strength increased by a factor of 2 compared with the unexposed samples or samples exposed to unsaturated conditions. The effect of saturation on the insulating castables was slightly beneficial at CO/H/sub 2/O = 1 and 3 where the flexural strength generally increased. Changes in weight, dimension, density-porosity, and MOR of refractory samples after a 60 day exposure in the ERDA atmosphere were basically the same as observed after 30 days in similar exposure conditions.
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification Fifteenth Quarterly Progress Report November 1 1979 January 31 1980 written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The dependence of the chemical reactions occurring in the cement bond portion of the castables upon the degree of saturation has now been determined for pure steam (500 and 1000 psia, 10 days), and the DOE atmosphere (1000 psia, 10 days). Boehmite, C/sub 4/A/sub 3/H/sub 3/ and calcite are the major components formed in the above mentioned atmospheres. Of these, only the amount of boehmite varied significantly with the degree of saturation of the atmosphere. A linear relationship exists between the percent saturation and the amount of boehmite up to approx. 70% saturation. Above approx. 70% saturation the amount of boehmite is nearly constant and independent of the degree of saturation. The minimum percent saturation required to form boehmite varied from approx. 10% to approx. 30% according to the atmosphere and pressure. The mechanical properties (namely flexural strength) also varied with the percent saturation along with the formation of new compounds. Those parts of the specimens exposed to>50% saturated atmosphere were appreciably stronger (2 to 3 times) than those parts in contact with an atmosphere whose saturation was
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification Tenth Quarterly Progress Report 1 August 1978 31 October 1978 written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During this quarter, the exposure tests of Task III were completed wherein the effect of repeated temperature/pressure cycling upon the mechanical strength of alumina castables containing boehmite was determined. Post-exposure characterization, consisting of weight and dimensional changes, density-porosity, and MOR of all samples (seven different refractory compositions, over 550 samples) and XRD and DTA/TGA of several samples, was also completed. Several experiments were performed to determine the change in the pH of the water in contact with various gases.
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification Second Annual Progress Report May 1 1977 April 30 1978 written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With the exception of the weight and porosity changes for the cement bonded castables immersed in water during exposure, the properties of the various refractories after long-term (60-days) exposure in the unsaturated and saturated DOE atmospheres were similar to those observed in 10 to 30 days DOE or CO-Steam atmospheres. The major changes in properties occur within relatively short times, a few days, and depend more upon the degree of saturation of the atmosphere than upon exposure time. Except for the CO/H/sub 2/O = 3.0 atmosphere, all the cement-bonded castables showed higher strengths in saturated than in non-saturated atmospheres. Depending upon the CO/H/sub 2/O ratio, the liquid conditions were generally more reactive then the vapor. With increasing CO content of the atmosphere, the rate of dissolution of CaO increases, particularly for samples immersed in water. In the high alumina castables containing pure calcium aluminate cement, UMR-1 and 2, the strength tends to decrease with increasing CO/H/sub 2/O ratio. Other castables containing silica tend not to show as large a dependence of strength upon CO/H/sub 2/O ratio. No reaction has been observed between the various refractory aggregates and the gases in the DOE atmosphere (including steam), either saturated or non-saturated. In unsaturated atmospheres only calcite is formed. Both calcite and boehmite form in all of the cement-bonded high and intermediate alumina and insulating castables exposed to saturated atmospheres. In saturated atmospheres CaO is leached from the refractories, particularly those in contact with liquid, by a process highly dependent upon the CO/H/sub 2/O ratio.
Download or read book Chemical and Physical Stability of Refractories for Use in Coal Gasification Third Annual Progress Report May 1 1978 April 30 1979 written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Of all the refractories examined, the cement-bonded castables showed the most chemical reaction with the test atmospheres. In most cases, the reactions consisted of the formation of boehmite (Al/sub 2/O/sub 3/.H/sub 2/O) and CaCO/sub 3/ in saturated atmospheres (below 500/sup 0/F) while only CaCO/sub 3/ formed in unsaturated atmospheres (1000/sup 0/F). The formation of boehmite, especially in the dense alumina castables, resulted in large increases (doubling or tripling) of the flexural strength. No significant differences in chemical reactivity was noted between the three commercial calcium aluminate cements examined nor between different commercial or laboratory-prepared castables. Any differences between different manufacturers of the same type of refractory is at best a second order factor affecting their performance for the conditions investigated. Other property changes, such as weight, dimension, density, and porosity, especially those of intermediate alumina and insulating castables, were small. The physical/mechanical properties of phosphate-bonded refractories showed relatively little change except for specimens exposed to saturated atmospheres where a large reduction in flexural strength occurred. This reduction in strength is attributed to chemical attack of phosphate bond phases by high pressure, saturated steam. Steam and CO/CO/sub 2/ were the only gases found to react significantly with the refractories.
