The EPIC™ Clean Gasification System and other technologies could make coal and biomass the least expensive source of fuel for power generation and feedstock for process industries. In many applications, Syngas may be used as a substitute for natural gas as fuel and feedstock. Large-scale gasification technologies (such as the technologies currently available through General Electric, Lurgi, Shell, and ConocoPhillips) can produce a cost competitive Syngas, but high capital costs and complexity of such systems preclude this alternative for small- to mid-sized users.
The EPIC™ Clean Gasification System produces Syngas that:
- Is an environmentally acceptable fuel derived from coal and supplemental fuels such as sludge, solid waste and other low cost or negative cost feed stocks;
- Replaces natural gas at more stable long-term prices;
- Provides a technological solution to plants facing emission compliance issues;
- Offers superior mercury removal and carbon capture ready options; and
- Provides an alternative for customers with limited access to environmentally friendly, economically viable fuels.
The typical EPIC™ Clean Gasification System includes a coal handling facility with conveying system (either mechanical or pneumatic), a moving bed gasifier and accessories, a raw gas cleanup system and a sulfur removal/recovery system. Coal enters the gasifier at the top and travels downward while undergoing various stages of gasification and finally is discharged as dry ash from the bottom. The gas exits the vessel at two points with the upper gas consisting of the lighter fractions at a lower temperature. Both Syngas streams have particulate, liquids, and sulfur removed to acceptably low levels so that the Syngas can be used as a feed stock or fuel gas. The relatively small size and modular nature of the gasifier and accessories allows easy scale-up of the number of gasifiers as necessary to fit the needs of the customer.
The EPIC™ Clean Gasification System has lower capital costs, greater reliability, and less complex operation than the large-scale gasification technologies and can produce Syngas at a lower cost per Btu for small and medium sized users. The primary market for Syngas is as a fuel gas but a significant number of major potential customers have approached the Company about producing Syngas as an industrial feedstock.
The two main components of the EPIC™ Clean Gasification System are the gasifier unit and the sulfur recovery system.
The gasifiers are based on air-blown reactors and other equipment originally designed by TZM and employed in installations in China, South Africa and Eastern Europe with over 40 years of operating experience. The gasifier, shown at the left, is a relatively simple vessel with coal entry at the top, long-life refractory in the upper part (first stage), a steam producing water jacket in the lower part (second stage) and a rotating grate at the bottom. Coal enters the top of the gasifier through a lock-hopper system. As the coal moves down through the vessel, first inherent moisture and then volatile matter in the coal is driven off by heat rising from the lower part of the gasifier and exits the upper gas outlet. The devolatilized coal (char) is gasified in the lower section by steam and air entering through the grate at the bottom. The Syngas produced in the lower section exits the vessel at the low gas outlet. The granular, dry ash is pushed to two ash removal ports at the bottom by the rotating grate and exits the vessel through lock-hoppers into an ash handling system (mechanical or pneumatic). All aspects and components associated with the gasifiers and accessories are of robust design and offer long-life with easy access for maintenance. One gasifier produces a nominal output of 80-350 MMBtu per hour of Syngas depending on coal used and operating pressure of gasifier.
An equally important requirement of the EPIC™ Clean Gasification System is the removal of sulfur from the Syngas to an acceptably low level. Many gasification systems and chemical production plants used in China utilize an improved Stretford Process – originally developed in Britain. The EPIC™ Clean Gasification System incorporates the “888” sulfur recovery system (shown in the figure on the left) that has been used for more than twenty years and more than 300 installations with continuing upgrades of increasingly better catalysts.
With our technology partners, we have adapted a well-proven gasifier design for biomass applications. The EJ1ST-3.0 BM gasifier provides the capability to utilize certain problem biomass types such as poultry wastes. The design is modular and compact which allows a high degree of shop fabrication to minimize field installation. As most similar biomass substances do not have significant gas pollutants, the installation is relatively simple and the construction period is short. For poultry waste, the Syngas produced can be used in small power generation systems like a GE Jenbacher engine, as boiler fuel or processed to hydrogen.
The EPIC gasifier can be used to produce or co-produce value-added chemical products such as Hydrogen, Ammonia, Hydrogen Peroxide and Methanol. Syngas product streams are rich with the basic building blocks Carbon Monoxide and Hydrogen, which can be readily converted or separated to produce these basic chemicals, and more. Chemical synthesis can be tailored to produce the highest value products for a given marketplace.
The hardware systems needed to produce chemical products from EPIC Syngas are all based on well-proven, industry standard technologies. Downstream units are prefabricated, skid-built and properly sized for maximum efficiency. The use of modular systems, such as the membrane separation unit shown above and the water gas shift module shown at right, enables the distributed production of chemicals and can increase revenue streams by leveraging all of the gasification capacity at an installation.
EPIC IGCC Process
We are working closely with manufacturers of power generation equipment and have received approval of Syngas produced by the EPIC™ Clean Gasification System for industrial combustion turbines that range from 25 MW to 250 MW in an IGCC configuration.
The EPIC IGCC process is simple and does not require complex systems such as air separation plants. The EPIC system also recovers most of the water in the coal and uses it within the gasification process. The EPIC system is best suited for use with low-rank coals but will work with most coals. Low-rank coals typically contain higher water quantities and this may make the EPIC gasification a water contributor to an IGCC plant.
The EPIC IGCC provides a highly efficient coal-to-power gasification system. The use of multiple gasifiers, gas clean-up and H2S removal trains is cost effective and provides for high plant availability and reliability.
The high efficiency of the EPIC system is particularly well suited for repowering small to medium-sized coal plants. In repowering, the major portions of the existing plant (such as coal and ash handling, steam turbine generator and condenser, cooling water system, electrical and switchgear, control room and water treatment systems) are retained. The new portions are the gasification, gas clean-up and H2S removal and gas turbine generator(s) with heat recovery steam generators. When the new systems are integrated with the old systems, the net plant output significantly increases; the net plant efficiency increases and emissions are significantly reduced.