Patent ID: 8355891
Filing Date: 2013-01-15
Classification: B01J,C01B

Abstract:
1. A method for the maintenance of a furnace for the catalytic steam reforming of a hydrocarbon reaction mixture, the furnace comprising tubes filled with catalyst, a first portion of the tubes T(j) being equipped with a thermocouple attached to a wall of said tube at a point Y t (j), the other tubes T(i) being free thereof, the method comprising at least the following steps: 1) measuring periodically, for each tube, a temperature θp of the wall of the tube using a remote temperature measurement means; 2) measuring and recording continuously, for each of the tubes T(j), a second temperature θt(j) of the wall of the tube using a thermocouple attached to the lower portion of said tubes and connected to a data acquisition system capable of storing data for a time at least equal to the service life of the furnace, to establish a curve θt(j) as a function of the time; 3) calculating Δθ(j)=θp(j)−θt(j), for each tube T(j) and for each measurement θp(j); 4) establishing a virtual curve θt(i) 5) determining the hottest point of the tube and estimating the temperature difference Δθ 6) establishing a curve θmax(i) as a function of the time starting from the virtual curve θt(i) 7) deducing, in real time, and using the Larson-Miller relation, a remaining service life for each tube T(i), from the curve θ 8) comparing the remaining service life for each of the tubes with the time remaining before the next programmed shutdowns of the furnace; and 9) replacing the tubes that need replacing during each programmed shutdown.