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On March 23, 2009, the unit underwent a minor shutdown for maintenance, and one of the main tasks during this maintenance was to replace the 109-D pre-conversion catalyst. Due to the fact that the pre-conversion catalysts replaced during last year’s maintenance at the Southwest Plant were never reduced, this led to an increased load on one of the furnaces, severely restricting the plant’s ability to operate at high loads. Before this maintenance campaign, the department’s technicians and senior managers conducted numerous evaluations and studies, and ultimately chose catalysts produced by the Liaohe Catalyst Factory. This was the third batch of pre-conversion catalysts manufactured by them, with the previous two batches performing well in the Jinxi ammonia synthesis plant. Below are the reduction data for the catalyst in this furnace. Since it is of the pre-reduction type, during reduction, once the temperature of the 109-D catalyst bed is raised to the designed value by steam, hydrogen is introduced, and then process gas is fed in, allowing for a slow reaction to take place. Below are the data from this catalytic reduction period: Time Load (%) TRCA04111 TI04114-2 TI04114-4 TI04115 PI04112 PI04113 Inlet gas composition Outlet gas composition Inlet gas temperature (°C) Catalyst bed temperature (°C) Catalyst bed temperature (°C) Outlet gas temperature (°C) Inlet pressure (MPa) Outlet pressure (MPa) Hydrogen Methane Hydrogen Methane 3.28 12:47 274 1139 9939 7384 1.12 1.10 3.28 13:47 354 334 1241 0403 2.37 2.35 3.28 14:47 364 513 9739 4390 2.33 2.31 3.28 15:47 314 624 1741 5410 2.87 2.84 3.28 16:47 334 624 2424 4214 202.82 2.78 14.75 79.93 25.15 63.53 3.28 17:47 364 804 2942 7426 3.02 2.98 13.58 79.06 33.12 54.72 3.28 18:47 334 794 2742 5423 2.23 2.29 16.32 74.93 33.78 53.72 3.28 19:47 354 063 6434 4345 2.26 2.22 13.85 79.25 40.33 8.33 3.28 20:47 334 944 3443 2431 2.33 2.29 14.25 78.89 30.21 59.03 3.28 21:47 364 734 1741 5415 2.34 2.30 12.88 0.42 8.52 60.62 3.28 22:47 354 744 1441 1410 2.27 2.23 5.11 90.46 24.58 66.16 3.28 23:47 354 804 1841 5413 2.27 2.23 3.29 0:47 354 794 1841 5414 2.27 2.23 4.71 91.16 24.44 66.65 3.29 2:47 354 794 1841 5414 2.27 2.23 3.29 4:47 354 814 1941 7415 2.27 2.23 3.29 7:47 354 744 1541 3411 2.27 2.23 4.89 0.62 4.23 66.02 3.29 10:47 354 834 1941 7415 2.26 2.22