It ain't rocket science ... well, now it is
Pumps and gasifiers aren’t rocket science, but when rocket scientists engineer these technologies, they are bad to the bone. The advanced propulsion experts at Pratt & Whitney Rocketdyne, who deliver rockets and shuttles to the moon and outer space, have built a commercial-scale dry solids pump designed to continuously feed coal and biomass into high-pressure environments such as a gasifier.
The company has partnered with the Energy & Environmental Research Center on the University of North Dakota campus in Grand Forks, where a commissioning ceremony for the technology was held this week. The event featured dignitaries such as North Dakota Gov. Jack Dalrymple, U.S. Sen. John Hoeven and the state’s lone representative in the U.S. House, Rick Berg.
The high-pressure dry solids pump and supporting gear, a massive prototype several stories high, relies on the ability of coal or biomass to form stable, load-bearing arcs between the sidewalls of the pump. The arcs can support very large loads, and the feedstock between the belts become trapped, or locked, and with the mechanical movement of the belts, a fixed rate of the trapped feedstock is forced (pumped) into a discharge chamber. The material is then fed into a high-pressure tank to feed a gasifier. The pump can process 400 tons a day of dry solid fuel without the need for water to make slurry, a unique feature of the system.
One of the major accomplishments of the pump technology is that it allows for gasification systems to be scaled way down. The pump that was commissioned this week is only part of Pratt & Whitney Rocketdyne’s compact gasification technology, which the company says is 90 percent smaller than competing systems while providing 25 percent reduction in cost with enhanced reliability. The capital cost to build a commercial-scale compact gasification plant using Pratt & Whitney Rocketdyne’s technology is estimated to be up to 20 percent less than conventional gasification plants. It also is figured to reduce carbon dioxide emissions by up to 10 percent compared to standard gasification technologies.
The actual gasifier was not in Grand Forks, N.D., for the ceremony, it remains in Des Plaines, Ill., at the Gas Technology Institute. It features 12 injectors that feed the dry fuel and oxygen mixture into the chamber. The injection system rapidly mixes and reacts the feedstock to hit 99 percent carbon conversion and 80 to 85 percent cold gas efficiency.