Research On Chrome Free Refractory And Lining Structure Design For Coal Catalytic Gasifier

The coal catalytic gasifier is more advantageous than the traditional gasifier,and the high-chrome refractories used in traditional gasifiers are harmful to the environment and people.Therefore,it is very important to find a suitable chrome-free refractory for coal catalytic gasifier.Meanwhile,due to the addition of the catalyst?K₂CO₃?in the coal catalytic gasifier,the production efficiency has greatly improved.However,when the furnace temperature is lower than the dew point temperature,the catalytic of K₂CO₃ will condense on the furnace wall,which exacerbates the wall damage.In order to meet the requirements of the outer wall temperature during the gasification process,the design of lining structure is also essential.In this paper,the corrosion resistance of refractory materials such as calcium hexaluminate,magnesium aluminum spinel?AR90?AR78?,tabular corundum and magnesia chrome sand against K₂CO₃ were first studied,then five kinds of castables with different compositions were prepared on the basis of it,and the sintering properties and slag resistance of the castables were compared.Through the optimization of material properties and simulation design of the structure,it is possible to meet the requirements of the lining materials used in the coal catalytic gasifier,the conclusions are as follows:?1?Tabular corundum and magnesium chrome sand was seriously corroded by K₂CO₃,while the calcium hexaluminate and magnesium aluminum spinel can keep the original morphology,which indicated strong corrosion resistance against K₂CO₃,especially the calcium hexaluminate.?2?When the aggregate and fine powder are both calcium hexaluminate,the castable exhibited the best volume stability.The cold rapture strength and compression strength of the castable after firing at 800?were 12.5MPa and105.2MPa respectively.The abrasion performance was also good,which showed volume loss of 6.49cm³.Meanwhile,the penetration depth of K element in the castable was 1.65mm,which presented the best slag resistance.?3?Optimization of material properties with the SiO₂ powder were studied,the results showed that with the increase of Si O₂ powder content,the compactness of calcium hexaluminate castables increase as well.When the content of silica powder was 3%,the cold rapture strength and compression strength of the castable after firing at 800?were 14.3MPa and 107.6MPa;The abrasion test presented only 3.62cm³ of volume loss,also the thermal residual strength retention rate at 1100?after five times water quench was up to 37.13%.After slag corrosion test,the penetration depth of K element in the castable was less than 1mm.?4?When the lining materials was composed of calcium hexaluminate castable or corundum castable with the thickness of 160mm and high-alumina castable with the thickness of 80mm,the outer wall temperature can meet the requirements.Combination of wave structure of metal anchor and ceramic anchor can minimize thermal stress.