This paper presents a study of the thermal and thermal stress state of a methane pyrolysis reactor for hydrogen recovery which has the form of a quartz cylinder filled with tin. To determine the temperature state, the problem for the two-layer (quartz-tin) structure using the Heaviside function was reduced to the problem for a single-layer structure with variable (piecewise homogeneous) properties of the material. An analytical solution including algebraic polynomial functions with coefficients exponentially stabilizing in time was obtained by determining the position of the temperature perturbation front and additional boundary conditions using the integral heat balance method. The obtained solution was used to determine quasi-static temperature stresses in the case where the structure is a two-layer hollow cylinder (flat deformation). The layer matching method was used to obtain an exact analytical solution of the thermoelasticity problem, from which it follows that at the point of contact of the layers, the hoop and axial stresses have a jump (discontinuity) with a change of sign at it. It is found that in some startup modes, the hoop and axial stresses can exceed the tensile strength of the quartz layer. The results were used to determine startup modes in which the stresses do not exceed permissible values.
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