What is the maximum ratio of acidic gas diversion in a sulfur recovery unit?

It seems there are no specific regulations for this; it should be adjusted based on the actual temperature of the combustion furnace. Keep an eye on it to see if any experts provide answers.

In the case of ammonia combustion, in order to raise the temperature at the front part of the furnace to over 1350°C so that the ammonia can be completely decomposed, a portion of the clean acidic gas is usually diverted to the middle section of the furnace, with the diversion rate being around 10-30%.

It mainly depends on the temperature: if the temperature in front of the furnace is too high, above 1350°C, reduce the diversion of acidic gases in the furnace; if the temperature is too low, increase that diversion.

Is there any particular consideration regarding the location of the diversion? I’ve seen some placed in the middle of the furnace, while others are located after the waste heat boiler – what are the advantages and disadvantages of each approach? Furthermore, what is the maximum amount of acid gas that can be diverted?

I think the original poster is very interested in knowing the maximum level of acid gas diversion that can be achieved. I believe this depends on specific circumstances; the poster might as well provide the process parameters, and then we can help analyze it. There are two possible locations for diversion: one is behind the partition wall inside the combustion furnace, and the other is at the outlet of the gas pipeline in the waste heat boiler.

What are the advantages and disadvantages of these two classifications? Please give me some advice!

In the case of ammonia burning, the sulfur recovery unit diverts a portion of the clean acidic gas (10-30%) to the middle section of the reaction furnace. Its purpose is to put the aminoacid-containing gas and the remaining clean acidic gas near the burner in a peroxide state, in order to raise the temperature and completely decompose ammonia. At this time, the cleaned acidic gas can only be diverted to the middle of the furnace. I’ve never heard of the diversion to the waste boiler outlet mentioned by the owner; I wonder if you are operating under ammonia combustion conditions?

1. The introduction of gas at the inlet is intended primarily to raise the temperature inside the sulfur production furnace, so as to reach the 1250-degree temperature required for ammonia combustion. Relying solely on feeding material from the front of the furnace will result in higher temperatures in the front section and lower temperatures in the rear section. When ammonia-containing gases enter, they do not decompose completely, which leads to the formation of ammonium salts in the subsequent pipelines, causing blockages. 2. The flow rate is adjusted at any time, primarily based on the temperature of the furnace. When the furnace temperature is low, more acid gas is diverted, as the components of the acid gas vary, so there is no fixed proportional relationship. 3. Excessive diversion can also lead to incomplete reaction of the sour gas, which then enters the subsequent boiler, resulting in poor reaction efficiency ； If the acid gas contains ammonia, the diversion of gas is reduced, the furnace temperature drops, and it may not reach 1250 degrees; this can result in incomplete decomposition of ammonia. 4. The reaction time of acidic gases in the furnace is generally only 1 second or even less; since the time is so short, and they enter from the back, it becomes even shorter.

First, it is necessary to maintain the temperature of the reaction furnace; second, the ratio of hydrogen sulfide to sulfur dioxide must be 2:1, so the concentration cannot exceed 66.6%. Otherwise, this 2:1 ratio cannot be maintained.

I believe there are two purposes for diversion: 1) to ensure that the temperature at the front of the furnace exceeds 1250 degrees, which facilitates ammonia combustion and ensures its complete decomposition; 2) diversion allows for adjusting the ratio of acidic gases to sulfur dioxide entering the Claus process, thereby enhancing the efficiency of the Claus reaction. The advantages can compensate for the excessive combustion of acidic gases aimed at raising the temperature of the front furnace. Before mastering the technology, the acidic gases entering the furnace can be completely or partially burned to produce sulfur dioxide, releasing heat of over 1250 degrees. The amount of gas diverted can be adjusted based on the ratio of acidic gases to sulfur dioxide analyzed in the later stages; if hydrogen sulfide levels are high, less gas should be introduced from the front, while if its levels are low, more gas should be diverted. I welcome your feedback on my views: handshake