Cost Effective Improved Refractory Materials for Slagging Gasification Systems

72067-Gasification is one of the most efficient methods of producing electricity from coal and other solid fuels. However, high temperature, slagging gasifiers have refractory liners that deteriorate rapidly and have a relatively short life, requiring considerable, costly maintenance. Depending on operating temperature, unit size, and feedstock, refractory liners typically last 6-18 months and replacement costs exceed $1 million, including materials, manpower, and lost revenue due to downtime. Additionally, these refractories contain chrome oxide, which causes health and environmental concerns due to the potential of carcinogenic hexavalent chrome formation during use. This project will develop an advanced, improved refractory material for use in a coal-fed gasifier. This material will be free of chrome oxide, cost less than 50% of currently used chrome oxide-bearing refractories, and provide an estimated life expectancy of at least three years in a coal-fed gasifier application. In Phase I, an economical, advanced refractory ceramic material for coal-fed slagging gasifiers was demonstrated. Over 25 ceramic material compositions were formulated, formed into specimens, and tested for strength, density, porosity, and static cup brick slag corrosion. Three compositions met all technical/ economical objectives: absence of chrome/chrome oxide, good ceramic formability (at lab-scale), average flexural strength over 2,000 psi, static cup brick slag corrosion/penetration not greater than 2 mm, and a preliminary estimated cost that would be 50% less than of current gasifier refractory materials. In Phase II, test results from Phase I will be used for further ceramic material development/optimization and a scaling-up of process techniques. Full size ceramic shapes will be produced and tested in a full size gasifier. Commercial Applications and Other Benefits as described by awardee: Economical refractory materials that contain no chrome oxide and provide excellent high temperature corrosion resistance should find use as refractory linings in solid feed gasifiers, molten metal (e.g., stainless steel) furnaces that yield slags, and chemical reactors that produce corrosive chemicals. The benefits of such a refractory material would include excellent corrosion resistance, lower cost (i.e., more than $500,000 potential average refractory savings per gasifier), longer life, and environmental safety.