Start-up method for coal gasification plant

Claim 1

A method for initiating operation of a plant for the gasification of solid carbonaceous material containing chlorine by heating a gasification reactor having a refractory lining to a temperature profile sufficient to permit autothermic operation of the gasification process wherein said plant includes equipment fabricated in part from materials susceptible to chloride induced stress corrosion cracking in the presence of oxygen; the method comprising: a. combusting a near stoichiometric mixture of a combustible fuel and an oxygen containing gas to produce an exhaust gas containing essentially no free oxygen; b. diluting said exhaust gas with a diluent gas containing essentially no free oxygen to produce a product gas of a mixture of diluent gas and exhaust gas; c. introducing a flow of said product gas at a temperature above 500° F. to said reactor; d. measuring the temperature of said product gas introduced to said reactor; e. increasing the temperature of said product gas flowing to said reactor in response to the temperature of said product gas within said reactor to increase the temperature of said product gas within said reactor at a rate sufficiently low to prevent thermal induced cracking of said refractory lining; f. increasing the temperature of said product gas within said reactor until said reactor achieves said temperature profile; g. discontinuing said flow of said product gas to said reactor when said reactor achieves said temperature profile; and thereafter, h. initiating said gasification process whereby said reactor is heated to said temperature profile necessary to permit autothermic operation of said gasification process while abating stress corrosion cracking of said materials by operation of chlorine liberated from said carbonaceous material during said gasification process.

Claim 2

A method for initiating operation of a plant for the gasification of solid carbonaceous material containing chlorine by heating a gasification reactor having a refractory lining to a temperature profile sufficient to permit autothermic operation of the gasification process wherein said plant includes equipment fabricated in part from materials susceptible to chloride induced stress corrosion cracking in the presence of oxygen; the method comprising: a. combusting a near stoichiometric mixture of a combustible fuel and an oxygen containing gas to produce an exhaust gas containing essentially no free oxygen; b. diluting said exhaust gas with a diluent gas containing essentially no free oxygen to produce a product gas of a mixture of diluent gas and exhaust gas; c. introducing a flow of said product gas at a temperature above 500° F. to said reactor; d. measuring the temperature of said product gas introduced to said reactor; e. increasing the temperature of said product gas flowing to said reactor in response to the temperature of said product gas within said reactor to increase the temperature of said product gas within said reactor at a rate sufficiently low to prevent thermal induced cracking of said refractory lining; f. increasing the temperature of said product gas within said reactor until said reactor achieves said temperature profile; g. discontinuing said flow of said product gas to said reactor when said reactor achieves said temperature profile; and thereafter, h. initiating said gasification process whereby said reactor is heated to said temperature profile necessary to permit autothermic operation of said gasification process while abating stress corrosion cracking of said materials by operation of chlorine liberated from said carbonaceous material during said gasification process.

Claim 5

A method according to claims 2 or 3 wherein said near stoichiometric mixture is sufficient to produce an exhaust gas containing a free oxygen content of no more than two percent (2%) by volume measured on a dry basis.