Questions regarding controlling the high rate of temperature rise in the converter during the startup of an ammonia synthesis plant?
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When starting up the ammonia synthesis plant, after the temperature rise and reduction processes for the first furnace, the second furnace, and the high and low-pressure shift catalysts are completed. When feeding raw gas to a furnace, why is it necessary to pay attention to the temperature of the shift converter? What are the specific requirements, and what factors can cause the catalyst in the shift converter to reach high temperatures and get damaged? I hope everyone will not hesitate to share their insights!
The temperature at high-variation areas should not be controlled too high, mainly because at high temperatures, the graphite in the catalyst can react with hydrogen to produce methane. Thereby damaging the catalyst. But it generally does not exceed the normal operating temperature. Our facility can use the steam-generating waste boiler before the high-temperature converter to control the inlet temperature of the high-temperature converter.
Could it be that this is due to the new or original CAT, which has higher activity, and it may not be fully restored either? After a period of gas introduction into the furnace, large amounts of hydrogen and carbon monoxide enter the high-voltage furnace, which can lead to a sharp rise in the temperature of the furnace bed and damage to the contacts. In high-variance furnaces, care must also be taken to control an adequate steam ratio and an appropriate reduction temperature, in order to prevent the reduction of Fe3O4. Also, for high-voltage sulfur injection, it must be injected thoroughly to the bottom! Generally, the high-temperature bed temperature in a high-temperature furnace is adjusted by controlling the inlet temperature of the furnace. It is quite important to control the stability of the high-voltage input temperature!
When driving to pick up gas, use normal pressure or a lower pressure for gas intake, and increase the pressure gradually. During this process, make sure that any backflow in the pipelines is promptly discharged; otherwise, the condensate will be carried into the converter, causing the catalyst to break down and reducing its activity