Change furnace temperature
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Let me ask a basic question: What is the fundamental reason why the temperature of the conversion furnace increases due to the increase in oxygen content in the gas? Thanks.
It should be that the heat of combustion has increased, and secondly, the combustion is more complete.
The catalyst oxidation reaction releases a large amount of heat, causing the bed temperature to rise rapidly
The active components in the catalyst undergo a violent oxidation reaction with oxygen, releasing a large amount of heat, causing the bed temperature to rise significantly and the catalyst to become deactivated.
What are the main components that react with oxygen? Want to know more.
The main reason is that the catalyst is desulfurized and releases a large amount of heat, causing the furnace temperature to rise.
Personal consideration is: 1. The upper part of the conversion furnace is equipped with an oxygen removal layer. The greater the oxygen content in the raw gas, the more heat is released here, and the temperature rises accordingly. 2. Oxygen will react with the sulfated shift catalyst to generate sulfate.
I think current conversion furnaces generally do not have a peroxide protective layer. This is usually found in low-temperature Claus reactors for sulfur recovery!
Generally, there is no peroxide protective layer. If there is, it is possible that methanation reaction has occurred.
If the oxygen content in the gas exceeds the standard, the catalyst will be oxidized and release a lot of heat, which will burn the catalyst. The reason should be a gasification problem. The gas should be vented immediately to prevent accidents.
After the catalyst is used for a long time, the surface of the catalyst will coke, the oxygen content will increase, and it will spontaneously ignite. This is how our catalyst is regenerated. The process air is introduced and burned!
This depends on what type of catalyst the poster uses. Since in the gas purification area, it is generally a sulfur-tolerant shift catalyst. The active components of the catalyst are sulfated Co and Mo. When there is oxygen, the sulfated Co and Mo will become oxidized Co and Mo. There are also anaerobic catalysts. The active components of high-variable catalysts are reduced Fe and Cr. The active components of low-variable catalysts are reduced Cu and Zn. When there is oxygen, they will oxidize and release heat with these active components. Another thing is that the conversion gas contains CO and H2, which will react with oxygen at high temperatures and also generate heat. This post was last edited by yxjwp on 2009-4-21 09:05 ]
The main reason is that the catalyst undergoes a desulfurization reaction. The desulfurization releases a large amount of heat, causing the bed temperature to rise. When the temperature is too high, a methanation reaction will occur, and the furnace temperature will rise sharply, burning the catalyst!
The general explanation mechanism is the exothermic reaction between oxygen and catalyst. But in the long run, there must be a process in which the catalyst is reduced by hydrogen and CO at the same time, so the overall reaction should be the oxidation and exotherm of hydrogen and oxygen under the action of the catalyst. This can also be confirmed by the fact that high oxygen content can easily lead to explosions. After all, simple catalyst oxidation is difficult to explode. Only rapid combustion of gas can easily explode.
Oxygen can react violently with catalyst components to release heat
The catalyst and oxygen produce an exothermic reaction, the temperature rises, and the catalyst is more active in an oxygen-rich state.
The active components in the catalyst undergo a violent oxidation reaction with oxygen, releasing a large amount of heat, causing the bed temperature to rise significantly. For example, in full hypothermia, the active components cobalt sulfide and molybdenum sulfide are converted into cobalt oxide and molybdenum oxide when the oxygen content is high. This is a heat-proof reaction and can also cause catalyst deactivation.
Different catalysts must be treated differently: Medium-change Fe-Cr catalyst, in a strong reducing atmosphere (high H2), O2 reacts with H2 to generate water, accompanied by strong heat release. On a fully low-changing antioxidant catalyst, O2 reacts with H2 to form water as above. If the antioxidant catalyst is penetrated for various reasons, O2 will run to the next stage of low-shift catalyst, and will react with the active components CoS and MoS2 to form sulfate, causing it to be permanently deactivated and no longer generate the sulfide before reduction. At the same time, there will be an exotherm larger than the shift reaction heat.
should be specific to the catalyst. General sulfur-tolerant catalysts (cobalt-molybdenum series) will undergo a reverse sulfurization reaction. But the conditions for it to occur are when the process gas is low in sulfur, high in temperature, and has a high water-to-vapor ratio. So I personally think it is due to a protective oxygen-free reaction adopted by the catalyst to prevent it from being oxidized. The principle should be similar to the anti-oxygen leakage sulfur production catalyst in the primary reactor of sulfur recovery.: Add ferrous sulfide in the middle of the catalyst to react with the sample, thereby protecting the catalyst itself. :handshake Actively participate in 1# Jaguar
Oxygen reacts with the process gas in the shift furnace under temperature conditions to generate reaction heat. But I don’t know what the oxygen concentration you are talking about is. If the concentration is very small, the cause of the temperature rise is not necessarily caused by oxygen. It may be a violent shift reaction, or a methanation reaction, etc.
Since there is chemically adsorbed and physically adsorbed hydrogen on the catalyst, contact with air (oxygen) will cause violent oxidation and cause over-temperature, making the catalyst susceptible to permanent damage. At the same time, air entry can also generate S02, and sulfation will also occur to deactivate the catalyst and cause corrosion of downstream equipment.