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Title: Nonequilibrium sulfur capture and retention in an air cooled slagging coal combustor. Second quarterly technical progress report, January 1, 1996--March 31, 1996

Abstract

The objective of this 24 month project is to determine the degree of sulfur retention in slag in a full scale cyclone coal combustor. This effort will consist of a series of up to 20 parametric tests in a 20 MMBtu/hr slagging, air cooled, cyclone combustor. During the present reporting period, this combustor was tested for a total of 9 days in February and at the end of March. The tests at the end of March were the first ones in which excellent slagging combustor operation was achieved. This is the key requirement for implementing the test effort in the present project. Therefore, the combustor is now ready for testing under the current project, and initial tests are planned during the next quarterly reporting period, as per the project schedule.

Authors:
Publication Date:
Research Org.:
Coal Tech Corp., Merion Station, PA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
283482
Report Number(s):
DOE/PC/95102-T2
ON: DE96050064
DOE Contract Number:
AC22-95PC95102
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 8 Apr 1996
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; CYCLONE COMBUSTORS; TESTING; SULFUR DIOXIDE; AIR POLLUTION ABATEMENT; SLAGS; SORPTIVE PROPERTIES; PROGRESS REPORT; CALCIUM OXIDES; SORBENT INJECTION PROCESSES; STAGED COMBUSTION; AMMONIA; NITROGEN OXIDES; SULFUR; CAPTURE

Citation Formats

Zauderer, B. Nonequilibrium sulfur capture and retention in an air cooled slagging coal combustor. Second quarterly technical progress report, January 1, 1996--March 31, 1996. United States: N. p., 1996. Web. doi:10.2172/283482.
Zauderer, B. Nonequilibrium sulfur capture and retention in an air cooled slagging coal combustor. Second quarterly technical progress report, January 1, 1996--March 31, 1996. United States. doi:10.2172/283482.
Zauderer, B. Mon . "Nonequilibrium sulfur capture and retention in an air cooled slagging coal combustor. Second quarterly technical progress report, January 1, 1996--March 31, 1996". United States. doi:10.2172/283482. https://www.osti.gov/servlets/purl/283482.
@article{osti_283482,
title = {Nonequilibrium sulfur capture and retention in an air cooled slagging coal combustor. Second quarterly technical progress report, January 1, 1996--March 31, 1996},
author = {Zauderer, B.},
abstractNote = {The objective of this 24 month project is to determine the degree of sulfur retention in slag in a full scale cyclone coal combustor. This effort will consist of a series of up to 20 parametric tests in a 20 MMBtu/hr slagging, air cooled, cyclone combustor. During the present reporting period, this combustor was tested for a total of 9 days in February and at the end of March. The tests at the end of March were the first ones in which excellent slagging combustor operation was achieved. This is the key requirement for implementing the test effort in the present project. Therefore, the combustor is now ready for testing under the current project, and initial tests are planned during the next quarterly reporting period, as per the project schedule.},
doi = {10.2172/283482},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Apr 08 00:00:00 EDT 1996},
month = {Mon Apr 08 00:00:00 EDT 1996}
}

Technical Report:

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  • Calcium oxide sorbents injected in a stagging combustor react with the sulfur released during coal combustion to form sulfur bearing particles, some of which are deposited on the liquid slag layer on the combustor wall. Since the solubility of sulfur in liquid slag is low, the slag must be drained from the combustor to limit sulfur re-evolution into the gas phase. The objective of this 24 month project is to perform a series of 16 one day tests to determine the factors that control the retention of the sulfur in the slag that is drained from the combustor. In themore » present quarterly reporting period, 10 days of combustor tests were performed, bringing the total number of tests performed to 15. A wide range of operating conditions were tested including injection of metal oxide powders to achieve total mineral injection rates in excess of 400 lb/hr at coal mass flow rates of around 1000 lb/hr. It was determined that efficient sulfur capture requires calcium oxide particle sizes that are too small to be effectively retained in the combustor. On the other hand, injection of coarse calcium sulfate particles into the combustor sharply increased the slag viscosity, thereby reducing the slag flow rate and causing substantial revolution of the sulfur in the slag. It is tentatively concluded that conditions necessary for sulfur capture with sorbents and its retention in the slag cannot be efficiently achieved in one step in a cyclone combustor. It is further concluded that due to the increases in slag viscosity by calcium sulfate extremely high slag mass flow rates are required for sulfur retention in slag. Further tests in that direction are planned for the next quarterly reporting period.« less
  • The primary project objective is to determine the degree of sulfur retention in slag in a full scale cyclone coal combustor. This non-equilibrium process is a key step in the capture and retention of sulfur released during coal combustion by the interaction with calcium based sorbent particles. By encapsulating the sulfur bearing calcium particles in slag, the need for landfilling of this waste is eliminated. This objective will be implemented through a series of up to 20 one day tests carried out in a 20 MMBtu/hr air cooled, slagging combustor-boiler installation located in Philadelphia, PA. The project will consist ofmore » two tasks. Task 1 consists of the experiments conducted in the 20 MMBtu/hr combustor, and task 2 will consist of analysis of this data. All the operating procedures for this effort have been developed in the 7 years of operation of this combustor.« less
  • The objective of this 24 month project is to determine the degree of sulfur retention in slag in a full scale cyclone coal combustor with sulfur capture by calcium oxide sorbent injection into the combustor. This sulfur capture process consists of two steps: Capture of sulfur with calcined calcium oxide followed by impact of the reacted sulfur-calcium particles on the liquid slag lining the combustor. The sulfur bearing slag must be removed within several minutes from the combustor to prevent re-evolution of the sulfur from the slag. To accomplish this requires slag mass flow rates in the range of severalmore » 100 lb/hr. To study this two step process in the combustor, two groups of tests are being implemented. In the first group, calcium sulfate in the form of gypsum, or plaster of Paris, was injected in the combustor to determine sulfur evolution from slag. In the second group, the entire process is tested with limestone and/or calcium hydrate injected into the combustor. This entire effort consists of a series of up to 16 parametric tests in a 20 MMtu/hr slagging, air cooled, cyclone combustor. During the present quarterly reporting period ending September 30,1996, three tests in this project were implemented, bringing the total tests to 5. In addition, a total of 10 test days were completed during this quarter on the parallel project that utilizes the same 20 MMtu/hr combustor. The results of that project, especially those related to improved slagging performance, have a direct bearing on this project in assuring proper operation at the high slag flow rates that may be necessary to achieve high sulfur retention in slag.« less
  • The objective of this 24 month project is to determine the degree of sulfur retention in slag in a full scale cyclone coal combustor. This effort will consist of a series of up to 20 parametric tests in a 20 MMBtu/hr slagging, air cooled, cyclone combustor. During the present reporting period, this combustor was in the final stages of re-installation in a new facility in Philadelphia, PA following its relocation from a test facility in Williamsport, PA. Initial shakedown test on this new combustor facility began in December 1995, at the end of the present quarterly reporting period. The shakedownmore » tests will continue through the next quarterly reporting period in the first three months of calendar year 1996. SO{sub 2} is controlled by injecting calcium oxide based sorbents into the combustor to react with sulfur emitted during combustion. The spent sorbent is dissolved in the slag and removed with it, thereby encapsulating the sulfur in slag. Part of the sorbent exits the combustor with the combustion products into the boiler where it can react with the sulfur. The primary objective of the present tests is to maximize the degree of sulfur retention in the slag. All spent sorbent not reporting to the slag is either deposited in the boiler or it is removed in the stack particle scrubber.« less
  • Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles, which are deposited on the liquid slag layer on the combustor wall. Due to the low solubility of sulfur in slag, it must be rapidly drained from the combustor to limit sulfur gas re-evolution. Analysis indicated that slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 36 month project was to perform a series of tests to determine the factors that control the retention of the sulfur in the slag. 19 days of testingmore » were completed prior to 9/30/97. In the present quarterly reporting period ending 12/31/97, 13 tests days were completed on co-firing coal and a high ash, rice husk biomass, which was selected to produce a high slag flow rate. Most of the test effort focussed on developing methods for feeding the very low density rice husks into combustor. Various levels of mineral matter from coal ash, rice husk ash, calcium sulfate, and calcium oxide was injected in the combustor during these 13 tests. The peak mineral matter, injection rate was 592 lb/hr for a period of about one-hour. No significant sulfur concentration was measured in the slag removed from the combustor. This may be due to the brief test duration, and longer duration tests are planned for the next quarter. The two major accomplishments in this quarter are the successful co-firing of coal and biomass in the slagging combustor. This is a major technical milestone due to its application to greenhouse gas emission reduction. It was not in the original project plan. Also, the total of 31 test days completed by 12/31/97 is double the number originally planned.« less