Pratt & Whitney Rocketdyne (PWR) Compact Gasification Technology Available Through ZEEP

PWR Gasification System Description

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The PWR Compact Gasification System is an ultra dense solids feed system coupled with an oxygen-blown, single stage gasifier that converts low value carbonaceous feedstock into a syngas that is primarily carbon monoxide and hydrogen. Shown below is the integrated gasification system to be provided by PWR.

The gasification system consists of a low pressure solids hopper, which feeds the carbonaceous material to the Dry Solids Pump at atmospheric conditions. In a single stage, the Dry Solids Pump transfers the feed stock into the high pressure feed tank at a nominal pressure of 1200 psi. By controlling the differential pressure between the high pressure feed tank and the gasifier that operates at 1000 psi, the material flows through a static flow splitter to distribute the solids to the gasifier’s multiple burner ports.

The solids feed stock is reacted in the gasifier with oxygen and steam to generate syngas; then partially water quenched to reduce the syngas temperature. The syngas flows through commercially available solids cyclones and a candle filters to remove any particulate material. The syngas is then processed to generate electricity or to produce chemicals, liquid fuels, or hydrogen.

ZEEP Technology through PWR

The gasifier system is capable of processing feedstocks such as coal, petcoke, refinery residues and biomass into a value added syngas. The Compact Gasification System is being developed specifically to compete against existing commercial gasification systems to provide increased operating availability and efficiency, and reduced plant capital and operating costs.

Gasifier

The PWR gasifier operates at 1000 psig, and when combined with the multi-port burner, reduces gasifier size by 90% when compared to competing systems. The gasifier dimensions are approximately 40 inches internal diameter, and 40 feet in length from the feed splitter to the exit of the quench section. The gasifier consists of three sections: 1) gasifier burner head, 2) the gasifier reactor body with the water cooled liner, and 3) the quench section. The relatively small gasifier diameter is achieved with active wall cooling using water cooled metal liners configured to establish and retain a frozen slag layer that protects the liner during gasifier operation. This concept is similar to designs used in commercial gasifiers that are currently marketed and operated around the world.

Dry Solids Pump

Each train of the PWR gasification system is capable of processing up to 3,000 tons of hydrocarbon based feedstock per day. This system consists of a dry solids pump and ultra dense solids feed system for delivering high-pressure (>1200 psi) pulverized solids to the gasifier. The dry solids pump is being developed by Pratt & Whitney Rocketdyne. The innovative pump design uses a motorized tractor belt (metal links) to compress and transport the solids feed stock in a single stage process and delivers it into the high pressure feed tank. All the materials of construction, motors, and gear reduction assemblies are commercially available and do not require extensive development.

High Density Feed System and Flow Splitter

“Ultra-dense phase” solids flow is used to feed the gasifier injector system from the high pressure feed tank. The unique characteristic of ultra-dense flow is the solids void fraction of 55%, which creates a homogeneous solids flow that can be separated into multiple streams of equal mass flow rates. The PWR flow splitter design separates the solids flow into multiple burner ports, depending on gasifier size, to rapidly mix and combust the oxygen and carbonaceous feedstocks. The use of multiple burner ports allows faster mixing and reaction of the coal with oxygen and steam, thereby increasing carbon conversion and thermal efficiency.

ZEEP Deployment of PWR Compact Gasification Technology