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Waste Conversion to Hydrogen

AES has worked with gasification technology partners converting hazardous waste material to hydrogen that is clean enough to be taken into an adjacent H2 pipeline.

Located on property adjacent to the Clients facility in Texas, the site is permitted as a TSD (treatment, storage and disposal) by the Texas Commission for Environmental Quality ("TCEQ") facility to handle hazardous waste. The facility cleans railcars of residual materials and generates a wide range of Resource Conservation Recovery Act ("RCRA") hazardous wastes in the process. Currently, these wastes are sent offsite to a hazardous waste incinerator. The proposed recycling facility will convert the materials into industrial grade, high purity hydrogen and a non-hazardous solid residual, leach resistant, glass.

As a result of the notification requirements described under the Texas Administrative Code Title 30, Part 1, Chapter 335, Subchapter A, Rule 335.6, TCEQ provides for the documentation of hazardous materials that may be permitted for recycle. plasma melterThis recycle rule allows for the recycling of waste materials for the reuse of captured gases without the delay and cost associated with permitting a hazardous waste site. The approval is simply a letter from TCEQ permitting the recycle facility to use the permit owned by a company generating the waste material. The Facility will use the Plasma Melter to convert the organic fraction of the waste stream into synthesis gas. The waste stream is generated in the process of cleaning out the residuals from railcars. The hazardous waste will be stored on the permitted site under the conditions of their permit until needed as feed to the Plasma Melter.

The waste falls into four broad categories: filter cake produced in the railcar cleaning process, an oily sludge, and two types of fuel oil liquid. Filter cake will be transferred to the Plasma Melter via an auger and fed directly into the process feed hopper. This feed hopper will be designed to hold about 8 hours of feed material and will be refilled on demand. The liquid wastes will be periodically transferred from the TSD to the Facility where it is staged in a day tank for processing in the Plasma Melter system. It is anticipated that no more than 24 hours of feed materials will be brought to the waste staging area at one time. In addition, waste material that is received at the TSD from off-site hazardous waste generators will also be transferred to the recycle facility if the waste materials meet the feed acceptance criteria for the Plasma Melter. As engineered, the Plasma Melter is anticipated to process up to 23 tons of waste per day.

During Phase 1 of the planned recycling operation, a pressure swing absorption ("PSA") unit developed and produced by gas production company, will be used to extract the hydrogen from the syngas. The PSA tail gas (CO, CO2, N2 and H2O) will be sent to a boiler to recover the energy value from the CO. During Phase 2, the syngas will be processed through a water Gas Shift Reactor (WGSR) to convert the CO to additional hydrogen and carbon dioxide. Following that step, the shifted hydrogen gas mixture is processed in a PSA unit to purify the hydrogen. It is anticipated that the systems as engineered will produce up to 59,154 MMBtu’s per year of pure hydrogen.

Cellulosic Bio-mass to Bio-Fuels

AES is working with gasification technology partners to convert cellulosic pine wood materials to ethanol and methanol.

The cellulosic, pine to ethanol project will use the Plasma Melter and Gasifier as a core element of the gasification process. The Plasma Melter and Gasifier is an integration of a low temperature shaft gasifier and Plasma Melter. The Plasma Melter system has been previously designed and installed in 4 different sizes a total of 7 times in different applications around the world (USA, Japan, and Taiwan). ethanolThese applications were for the destruction of carbon based waste materials (hazardous and medical waste) using steam reforming gasification. IET still offers these PEMTM systems to the chemical and petroleum industry in the US and abroad.

During early 2006, the manufacturer has developed the latest design concept, the Plasma Gasifier. This system is a combination of the basic Plasma Melter and a shaft gasifier. The combination of these two systems allows a large increase in system processing throughput (~5X to 6X) compared to the Plasma Melter alone with a minimum increase in system capital cost primarily associated with the larger gas cleaning system components.

In this integrated system, the shaft gasifier performs most of the biomass gasification at moderate temperature and produces a typical mixture of syngas, organics and carbon associated with such gasifiers. This integration increases the system gasification capacity with lower energy consumption for the gasification reactions than the Plasma Melter alone.

The high temperature Plasma Melter effectively gasifies the carbon residuals coming from the shaft gasifier into a very clean syngas. The Plasma Melter along with the proven syngas cleaning system used in previous PEMTM applications, assures the total removal of any residual organics and production of clean syngas suitable for subsequent conversion into ethanol in a catalytic system. The packed column wet scrubber operates with a caustic and assures removal of any acid gases from the syngas. In this configuration, the Plasma Melter eliminates problems in "gas cleaning" caused by the tars and oils that are formed in traditional shaft gasifiers. The syngas must be very clean to be used for catalytic ethanol production.

In addition to the syngas upgrading and cleaning function of the high temperature Plasma Melter, the system melts any ash from the biomass into a glass bath at the bottom of the Melter. This allows the system to process a wide range of ash bearing materials without concern for ash slagging problems as the system is designed to produce a controlled viscosity glass that can be removed on demand.

Once clean syngas is produced, a portion of the syngas is then sent to a catalytic subsystem for the subsequent production of ethanol. The system will produce a combination of methanol and ethanol as products.