Carbon Dioxode Recovery: Large Scale Design Trends

Abstract

Abstract With renewed interest in enhanced oil recovery (EOR) as existing fields become depleted, there is renewed interest in supplying CO2 for flooding by CO2 recovery from flue gas. This paper examines key design and operating issues and trends for new unit designs which hold the potential for reducing the plant investment and operating costs associated with this source of CO2. The emphasis is on conventional processes using chemical solvents for CO2 removal (such as Fluor Daniel's ECONAMINE FGSM process) as these are either commercial or have been successfully pilot tested. Developments in new tower packings and solvents and their potential impact on plant and operating costs are discussed, as are the effects on these costs of the flue gas source. Operating and capital recovery cost data are provided for 1,000 tonne/d plants which would be a typical size for an EOR project. Introduction In the mid 1980s, when crude oil prices were over $30 per barrel, several plants came on line in West Texas in the U.S. which used 30 wt% MEA with special inhibitors to extract CO2 from boiler flue gas for use in EOR. However, when the price of crude oil dropped dramatically, these plants quickly became uneconomic and were scrapped. The then existing process licensors, Dow Chemical and Union Carbide, became less active in promoting these technologies and in 1989 Dow Chemical sold their FT-1 process to Fluor Daniel Inc. Fluor renamed the technology "ECONAMINE FG" and has since licensed three commercial plants, one 320 tonne/d plant at Bellingham, Massachusetts, U.S.A. (1989), a 150 tonne/d plant for Sumitomo Chemical at Chiba, Japan (1993) and a 90 tonne/d plant for Prosint Produtos Sint?ticos at Rio de Janeiro, Brazil (1997). All plants sell CO2 primarily to the food industry. The Bellingham plant, which has a gas turbine exhaust flue gas source, was constructed by Fluor. The Sumitomo plant was constructed by Mitsubishi Heavy Industries (MHI) with the flue gas source from a boiler fired by a variety of fuels including heavy fuel oils. The Prosint plant was owner-constructed and has a boiler flue gas feed source. In addition, Fluor has performed a number of studies, several of which involved large-scale plants (1,000 tonne/d and larger). These studies were prompted by interest in using the CO2 for EOR and to avoid the new carbon tax being imposed in EC countries. In addition, the company designed two pilot plants for Japan which were used by the owners to study the process for greenhouse gas mitigation purposes. The results from the KEPCO pilot plant have been reported in the literature(1,2). Much of the KEPCO work is applicable to EOR applications as will be discussed later in this paper. Interest in greenhouse gas emission mitigation has spawned a number of processes for capturing CO2 from boiler stacks that differ considerably from capture by chemical solvents. None of these processes are presently offered commercially and most will remain in the laboratory study phase at least for the near future.