Upgrading of Low-Rank Coals - National Energy Technology ...

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Testing of ENCOAL Coal Derived Liquid samples. 6 Location The demonstration plant is located in Campbell County, Wyoming, approximately 10 miles north of the county seat of Gillette. The site is within Triton’s Buckskin mine boundary, near the mine’s rail transportation loop. Active coal mining and reclamation operations surround the demonstration plant site. The ENCOAL plant was located at the Buckskin mine site to take advantage of the existing mine facilities and to reduce capital and operating costs. Product Characteristics Specification PDF is a stable, low-sulfur, high-Btu fuel similar in composition and handling properties to bituminous coal. CDL is a low-sulfur industrial fuel oil that can potentially be upgraded for chemical feedstock or transportation fuels. These alternative fuel sources were intended to significantly lower current sulfur emissions at industrial and utility boiler sites and reduce pollutants that are acid rain precursors. Operating History Design and Initial Operation In September 1990, a Cooperative Agreement was signed between ENCOAL and DOE to initiate the project. The LFC process had been undergoing development in laboratory settings since the early 1980s. In the two years following the signing, the main focus was on the construction of an operable plant. The first 24-hour run took place in June 1992. In September, the plant achieved a continuous one-week run. A month later, the first shipment of 60,000 gallons of CDL was sent to TexPar, Inc., which experienced unloading problems. These problems were solved with heat tracing and tank heating coils. Although improved in heating value, early batches of PDF revealed a tendency to self ignite. After attempting to stabilize PDF using in-plant equipment, it was concluded that a separate, sealed vessel was needed for product deactivation, and a vibrating fluidized-bed (VFB) reactor was installed in 1993. ENCOAL shipped its first train containing PDF in September 1994 to Western Farmers Electric Cooperative in Hugo, Oklahoma. Three runs early in 1994 processed approximately 4,300 tons of coal, producing nearly 2,200 tons of PDF and 81,000 gallons of CDL. The second quarter of 1994 saw 54 days of continuous operation, followed by a 68-day run in the fourth quarter. However, deactivation in the VFB reactor was not complete: stabilization still involved “finishing” using outdoor pile layering or blending with ROM coal. Environmental Health & Safety Compliance with federal and state environmental regulations has been an important goal for the ENCOAL project. Regular Mine Safety & Health Administration
(MSHA) inspections since 1990 yielded only 10 minor noncompliance citations. With the exception of one Notice Of Violation, Wyoming state inspections were consistently positive. Stack and emissions testing completed in November 1995 indicated that the plant is operating within permitted limits for NO x , sulfur oxides, carbon monoxide, volatile organic compounds, and particulates. Although the plant’s tall structures, hot gases and large rotating equipment would seem to create potential for injury, one of the project’s most important accomplishments is its safety record. As of May 31, 1997, ENCOAL staff and their subcontractors had amassed over four years without a lost-time accident. Process Improvements As a first-of-its-kind enterprise, design and process difficulties were not unexpected, and much effort was devoted to solving those problems, especially that of PDF deactivation. As ENCOAL teams resolved obstacles, the duration of plant runs lengthened, with some months exceeding 90% availability. PDF and CDL were produced and shipped using conventional equipment and successfully test burned at industrial sites. Marked improvement in operations was achieved as a result of introducing the VFB reactor. Because it improved PDF stability, this new equipment made it possible for the first time to ship PDF for test burns. At the same time the VFB reactor was being installed, several other changes paved the way for increased PDF and CDL production. Tank car loading facility for Coal Derived Liquid at ENCOAL demonstration plant. The ENCOAL project has demonstrated for the first time the integrated operation of several unique process steps: • Coal drying and devolatilization on a rotary grate using convective heating • Integral solids cooling and deactivation • Integral cooling and rehydration using internal process water streams • Combustors operating on low-Btu gas from internal streams • Solids stabilization for storage and shipment Test Burns Commercialization of PDF took a major step forward in 1994, when ENCOAL shipped six trains to two customers. Shipments to the first customer, the Western Farmers Electric Cooperative, started with a 15% blend of PDF in raw coal and ranged up to 30% PDF, the upper level being determined by boiler capacity. Shipments to the second customer, Muscatine Power & Water in Muscatine, Iowa, started at 40% PDF and ranged up to 91%. The rail cars in this shipment, the first full unit train of 7
Page 1 and 2: TOPICAL REPORT NUMBER 10 ENCOAL Upg
Page 3 and 4: Trademark Notice The names PDF , C
Page 5 and 6: Introduction and Executive Summary
Page 7 and 8: Butte M O N T A N A Helena of low-r
Page 9: is purchased from Triton, which als
Page 13 and 14: Alternative Coal Testing In additio
Page 15 and 16: as well, and some indicate acceptab
Page 17 and 18: Rosebud SynCoal Project Description
Page 19 and 20: Two-Stage Dryer/Reactors High-Moist
Page 21 and 22: egular inspections. It was noted at
Page 23 and 24: Commercial Plant Design Western Syn
Page 25 and 26: the addition of SynCoal to the firi
Page 27 and 28: List of Acronyms and Abbreviations

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