Download or read book Attrition Resistant Zinc Titanate containing Reduced Sulfur Sorbents and Methods of Use Thereof written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Reduced sulfur gas species (e.g., H.sub. 2S, COS and CS.sub. 2) are removed from a gas stream by compositions wherein a zinc titanate ingredient is associated with a metal oxide-aluminate phase material in the same particle species. Nonlimiting examples of metal oxides comprising the compositions include magnesium oxide, zinc oxide, calcium oxide, nickel oxide, etc.
Download or read book Attrition Resistant Zinc Titanate containing Reduced Sulfur Sorbents written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The disclosure is directed to sorbent compositions for removing reduced sulfur species (e.g., H.sub. 2 S, COS and CS.sub. 2) a feed stream. The sorbent is formed from a multi-phase composition including a zinc titanate phase and a zinc oxide-aluminate phase. The sorbent composition is substantially free of unreacted alumina.
Download or read book An Attrition resistant Zinc Titanate Sorbent for Sulfur Technical Report 1 March 31 May 1994 written by and published by . This book was released on 1994 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the continuing search for good sorbent materials to remove sulfur from hot, coal-derived gases, zinc titanate sorbents have shown great promise. The objective of this project is to extend the effort started last year on sorbents with little or no loss in chemical reactivity. The principle is to contain Zn2TiO4 in a structural matrix of excess TiO2. Progress on several tasks was made during the third quarter. The new fixed bed apparatus at SIUC was made operational, and experiments in it have started. The feasibility of using turbine exhaust gas diluted with N2 for sorbent regeneration was demonstrated through experiments at both SIUC and RTI. The third of four ten-cycle tests was completed at RTI. It was a fixed bed test on one to two promising formulations developed last year. The results followed the pattern of the fluidized bed tests completed earlier in that the chemical reactivity was good, except for the first few cycles. Lastly the undergraduate student design project on hot gas desulfurization hardware was completed this quarter.
Download or read book An Attrition resistant Zinc Titanate Sorbent for Sulfur Technical Report September 1 Through November 30 1993 written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Goethe Studien written by and published by . This book was released on 1943 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Attrition resistant Zinc Titanate Sorbent for Sulfur Quarterly Technical Report March 1 1993 May 31 1993 written by and published by . This book was released on 1993 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the continuing search for good sorbent materials to remove sulfur from hot, coal-derived gases, zinc titanate sorbents have shown great promise. The objective of this project is to extend the work of prior investigators by developing improvements in the compressive strength and, therefore, the cycle life of these sorbents without a significant loss in chemical reactivity. During the third quarter, the preparation and properties of sorbents with a nominal composition of 50% Zn2TiO4 and 50% TiO2 were studied. In differential thermogravimetric tests of reactivity, specimens sintered at 850 and 900°C both gave two identical sulfidation-regeneration cycles. Specimens sintered at lower temperatures showed evidence of degradation during the second cycle. Materials of this composition had lower crush strengths than for the composition 75% Zn2TiO4 -- 25% TiO2 reported earlier, but higher values than reported by other investigators. Future work will include the preparation and properties of a lot of material with a coarser structure and larger pores, and microscopic studies on all three lots of material.
Download or read book An Attrition resistant Zinc Titanate Sorbent for Sulfur Quarterly Report September 1 November 30 1993 written by and published by . This book was released on 1994 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the continuing search for good sorbent materials to remove sulfur from hot, coal-derived gases, zinc titanate sorbents have shown great promise. The objective of this project is to extend the effort started last year on increasing the strength and durability of zinc titanate sorbents with little or no loss in chemical reactivity. The principle is to contain Zn2TiO4 in a structural matrix of excess TiO2. A fluidized bed test was completed this quarter on the first of two promising sorbent formulations. The chemical reactivity in the form of breakthrough curves became progressively better over ten sulfidation-regeneration cycles. While the chemical reactivity was very good, the attrition resistance was only fair, due presumably to the conversion of Zn2TiO4 to ZnTiO3 during cycling. The next formulation to be tested is expected to be better in attrition resistance.
Download or read book Zinc Titanate Sorbents written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present invention provides a zinc titanate sorbent material useful in desulfurization applications. The zinc titanate material is in the form of generally spherical particles of substantially uniform chemical distribution. The sorbent material is capable of absorbing sulfur compounds from a gaseous feed in an amount of at least about 15 weight percent based on the weight of the sorbent. The sorbent material is prepared by a process including: (a) forming a zinc oxide/titanium dioxide dry blend, (b) preparing a substantially uniform aqueous slurry comprising the zinc oxide/titanium dioxide dry blend, organic binder, and at least about 1 weight percent inorganic binder based on the solids weight of the slurry, (c) spray drying the slurry to produce substantially spherical particles, and (d) calcining the particles at a temperature of between about 750.degree. C. to about 950.degree. C. The dry blend is formed by mixing between about 0.5 to about 2 parts zinc oxide having a median particle size of less than about 0.5 .mu., and about 1 part titanium dioxide having a median particle size of less than about 1 .mu. The slurry contains substantially no free silica and may be prepared by the process including (1) preparing an aqueous solution of organic binder, (2) adding the dry blend to the aqueous solution of organic binder, and (3) adding the inorganic binder to the solution of organic binder, and blend. Additional reagents, such as a surfactant, may also be incorporated into the sorbent material. The present invention also provides a process for desulfurizing a gaseous stream. The process includes passing a gaseous stream through a reactor containing an attrition resistant zinc titanate sorbent material of the present invention.
Download or read book An Attrition resistant Zinc Titanate Sorbent for Sulfur Final Technical Report September 1 1992 August 31 1993 written by and published by . This book was released on 1993 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the continuing search for good sorbent materials to remove sulfur for hot, coal-derived gases, zinc titanate sorbents have shown great promise. The objective of this project was to extend the work of prior investigators by developing improvements in the compressive strength and, therefore, the cycle life of these sorbents while maintaining good chemical reactivity. Fifteen formulations were prepared and evaluated. The best properties were obtained by blending relatively course (two micron) ZnO and TiO2 powders to obtain a composition of 50%Zn2TiO4-50%TiO2. When sintered at 1000°C, it had a compressive strength of 28 MPa or 147 N/mm, which is four times higher than values obtained by prior investigators. It also performed well in thermogravimetric analysis measurements of reactivity, both in screening tests and in simulated coal gas.
Download or read book An Attrition resistant Zinc Titanate Sorbent for Sulfur Technical Report December 1 1992 February 28 1993 written by and published by . This book was released on 1993 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the continuing search for good sorbent materials to remove sulfur from hot, coal-derived gases, zinc titanate sorbents have shown great promise. The objective of this project is to extend the work of prior investigators to obtain improvements in the compressive strength and, therefore, the cycle life of these sorbents without a significant loss in chemical reactivity. During the second quarter, parametric data were obtained on the percent porosity, crush strength, and chemical reactivity for a sorbent composition of 75% Zn2TiO4 - 25% TiO2. This material was sintered at temperatures ranging from 700 to 1100°C. Although more extensive reactivity tests are still needed, results to date indicate that the best combination of properties is obtained with a sintering temperature of 800 or 850°C. Also planned for the next quarter are evaluations of other sorbent formulations.
Download or read book Enhanced Durability of Desulfurization Sorbents for Fluidized bed Applications written by and published by . This book was released on 1992 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: To extend the operating temperature range and further improve the durability of fluidizable sorbents, zinc titanate, another leading regenerable sorbent, was selected for development in the later part of this project. A number of zinc titanate formulations were prepared in the 50 to 300 [mu]m range using granulation and spray drying methods. Important sorbent preparation variables investigated included zinc to titanium ratio, binder type, binder amount, and various chemical additives such as cobalt and molybdenum. A number of sorbents selected on the basis of screening tests were subjected to bench-scale testing for 10 cycles at high temperature, high pressure (HTHP) conditions using the reactor system designed and constructed during the base program. This reactor system is capable of operation either as a 2.0 in. or 3.0 in. I.D. bubbling bed and is rated up to 20 atm operation at 871[degrees]C. Bench-scale testing variables included sorbent type, temperature (550 to 750[degrees]C), gas type (KRW or Texaco gasifier gas), steam content of coal gas, and fluidizing gas velocity (6 to 15 cm/s). The sorbents prepared by spray drying showed poor performance in terms of attrition resistance and chemical reactivity. On the other hand, the granulation method proved to be very successful. For example, a highly attrition-resistant zinc titanate formulation, ZT-4, prepared by granulation exhibited virtually no zinc loss and demonstrated a constant high reactivity and sulfur capacity over 10 cycles, i.e., approximately a 60 percent capacity utilization, with Texaco gas at 750[degrees]C, 15 cm/s fluidizing velocity and 15 atm pressure. The commercial potential of the granulation method for zinc titanate manufacture was demonstrated by preparing two 80 lb batches of sorbent with zinc to titanium mol ratios of 0.8 and 1.5.
Download or read book Fluidizable Zinc Titanate Materials with High Chemical Reactivity and Attrition Resistance written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 .mu.m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO.sub. 3 ; and then indurating it at 800.degree. to 900.degree. C. for a time sufficient to produce attrition-resistant granules.
Download or read book Testing of Zinc Titanate Desulfurization Sorbents for Moving bed Applications written by and published by . This book was released on 1993 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sorbents developed for moving-bed systems must comply with a minimum of chemical and mechanical durability performance characteristics in order to be considered acceptable for long-term operation. Among the desired properties, a sorbent must have: (1) High chemical reactivity, as measured by the rate of sulfur absorption and the total sulfur loading on the sorbent. (2) High mechanical strength, as measured by the pellet crush strength and the attrition resistance; (3) Suitable pellet morphology, as given by pellet size and shape to promote good bulk flow ability and seasonable porosity to increase reactivity. Formulation 2A1.7M (UCI designation L-3787M) was selected by DOE as the baseline formulation for performance evaluation of Option 3 sorbents. This baseline formulation is a rounded zinc titanate sorbent containing a 2:1 Zn:Ti molar ratio, 1.7% molybdenum (equivalent to 2.5% MoO3), and 3% bentonite binder that had been previously tested under the Option 2 program. Zinc titanate sorbents were prepared by UCI as rounded spherical or ellipsoidal pellets. The fabrication procedure is targeted at achieving a balance of mechanical strength (crush strength and attrition resistance) and chemical reactivity by controlling the pellet internal porosity.
Download or read book Enhanced Durability of High temperature Desulfurization Sorbents for Fluidized bed Applications Zinc Titanate written by and published by . This book was released on 1992 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project are to identify and demonstrate methods for enhancing long-term chemical reactivity and attrition resistance of zinc ferrite and zinc titanate sorbents to be employed for desulfurization of hot coal-derived gases in a high-temperature, high-pressure (HTHP) fluid-bed reactor. The sorbent formulation specified for study during the base period of this project was zinc ferrite. Zinc titanate sorbents are being studied under two options to the base contract. Specific objectives of the zinc titanate sorbent development work are the following: The effect of following process variables was investigated o the performance of zinc titanate sorbents: Method of sorbent preparation, Composition of fuel gas, Zn to Ti ratio of the sorbent, Sulfidation temperature, and Superficial gas velocity. The effect of first three variables has been covered in RTI's 1991 paper (Gupta and Gangwal, 1991b), while the effect of temperature and superficial gas velocity is described here.
Download or read book Highly Attrition Resistant Zinc Oxide Based Sorbents for H2S Removal by Spray Drying Technique written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Primary issues for the fluidized-bed/transport reactor process are high attrition resistant sorbent, its high sorption capacity and regenerability, durability, and cost. The overall objective of this project is the development of a superior attrition resistant zinc oxide-based sorbent for hot gas cleanup in integrated coal gasification combined cycle (IGCC). Sorbents applicable to a fluidized-bed hot gas desulfurization process must have a high attrition resistance to withstand the fast solid circulation between a desulfurizer and a regenerator, fast kinetic reactions, and high sulfur sorption capacity. The oxidative regeneration of zinc-based sorbent usually initiated at greater than 600 C with highly exothermic nature causing deactivation of sorbent as well as complication of sulfidation process by side reaction. Focusing on solving the sorbent attrition and regenerability of zinc oxide-based sorbent, we have adapted multi-binder matrices and direct incorporation of regeneration promoter. The sorbent forming was done with a spray drying technique that is easily scalable to commercial quantity.
Download or read book Improving the Properties of Zinc Titanate based Sorbents for Sulfur Removal written by Jing Yang and published by . This book was released on 1995 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Composition Modification of Zinc Titanate Sorbents for Hot Gas Desulfurization Technical Report March 1 May 31 1995 written by and published by . This book was released on 1995 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: For new coal gasification systems, zinc titanate sorbents are being developed to remove sulfur from the hot product gas prior to its use in combined cycle turbines and high temperature fuel cells. Although most of the properties of these sorbents are very attractive, there are still concerns about durability over many sulfidation-regeneration cycles and zinc losses due to vaporization. Doping the zinc titanate with other metal ions could alleviate both concerns, which are the objectives of this project. After a screening study was completed, it was decided that Cr offered more promise as a dopant than Ni, Cu, Mg, and Al. Therefore six new sorbent formulations containing Cr were prepared, and they are now being evaluated with a series of bulk density, X-ray diffraction, crush strength and thermogravimetric analysis (TGA) measurements. Results to date suggest that, while Zn vaporization losses can be reduced with Cr additions, a penalty in chemical reactivity occurs. A fixed bed test was also completed this quarter on a Cr-containing formulation. The H2S breakthrough time was about 11 hours, and utilization of Zn in the sorbent was 60.5%.
