To what temperature should acidic gas be preheated
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In sulfur recovery systems that are designed or operated in this way, to what temperature are the acidic gases and air preheated? What I’ve seen is that the material is preheated to 160 degrees using steam at 1.0 MPa. If the factory doesn’t have steam of this pressure level, is it better to use steam at 3.5 MPa or at 0.6 MPA? (The steam generated internally at 1.0 MPa is not sufficient.) Is it true that the higher the preheating temperature, the better? This post was last edited by flower2008 on 2009-3-17 14:47.]
Acid gas preheating is primarily intended to maintain the temperature of the reaction furnace above 950 degrees. From the perspective of thermal reactions, a higher temperature is preferable, but the design temperature of the equipment must also be taken into account.
I’m not sure if it’s due to different processes, but in our process, the acid gas preheater is preheated using medium-pressure steam (3.9 MPa(G)) to a temperature of just over 200°C
When the temperature of the reaction furnace fails to meet the design specifications (especially during ammonia combustion), other auxiliary methods are often required to raise the furnace temperature, such as preheating the acidic gas and air. Steam at 3.5 MPa is typically used to preheat the acidic gas or air to around 200°C.
If the ammonia content in the acidic gas is below 5%, preheating is not necessary, and it has no impact.
The content of acidic gases is relatively low, around 35%
Heating with 0.6 MPa steam is probably not feasible, as the temperature is too low. Additionally, it is advisable to insulate the air pipelines in order to increase the temperature of the air entering the furnace. The temperature of the reaction furnace can also be increased by supplying additional fuel gas.
Is what the poster is referring to the process in which there is no combustion furnace, and the air and acidic gases are heated before being fed directly into the reactor where they undergo oxidation to produce sulfur? In such processes, 40 kg of steam is generally used to heat the materials to around 200°C.
There is no need to preheat acidic gases before feeding them into the furnace; our company feeds them directly into the sulfur production furnace, where the temperature exceeds 1100 degrees, so any kind of preheating is not possible
Our acidic gas also has a concentration of around 35%; the design calls for 3.8 MPag of steam, but this hasn’t been put into use yet, and the combustion temperature is around 1100°C. Such a high concentration can be handled without a preheating design
If ammonia is not being burned, it is possible to proceed without preheating.
It depends on the furnace temperature requirements you need; sometimes preheating is necessary to meet those temperature demands, as otherwise it will affect the process parameters, which is why preheating is carried out in advance.
The main consideration is whether to burn ammonia; if so, the preheating temperature must be at least 90 degrees or higher to prevent ammonium salts from crystallizing in the pipelines. As for the impact on the furnace temperature, the structure of the burner also needs to be taken into account.
Yes, steam at 0.35 pressure can also be preheated to 120 degrees
The acid gas preheating discussed here is something different from what you mentioned. What we are referring to is the preheating of clean acidic gas. Aminic gases must be equipped with heating or jackets, with the temperature maintained above 90°C; otherwise, salt formation can occur easily, leading to pipeline blockages.
Floors 13 and 14 likely describe the process of sulfur recovery in the coal chemical industry. In this industry, non-aminoacidic gases are converted into clean acidic gases, and preheating of these acidic gases is generally employed. Since this portion of acidic gas comes from the upstream low-temperature methanol wash at a temperature of 35–40 degrees Celsius, it mixes with the aminoacid-containing acidic gas before entering the system; the temperature of this latter gas is 110–130 degrees Celsius (this value varies from plant to plant and is determined based on the ammonia nitrogen content in the water). To prevent the crystallization of ammonium salts, this acidic gas is preheated, with a temperature of typically 0.30–0.45 degrees Celsius, depending on the availability of steam supply. However, there are also cases where superheated steam at 4.1 or 3.5 MPa is used, and this is employed to significantly increase the furnace temperature. For those using 0.30–0.46 MPa, it should be understood as preventing ammonium salt crystallization, rather than preheating. In the refining industry, when preheating is used, medium- to high-pressure steam is generally employed, and hot air is also used to facilitate an increase in furnace temperature. Active participation
That’s right. Adding heat tracing is to prevent ammonium salt crystallization; preheating does not refer to this. Ammonia burning generally requires a furnace temperature of at least 1250 degrees; preheating the acidic gas is one of the methods to increase the furnace temperature. The preheating temperature depends generally on the design requirements. Now, the oxygen-enriched process is also very useful for ammonia burning.
It depends on the requirements of the catalyst; the operating temperature is low at the beginning of its use but relatively higher later on. Generally, for sulfur recovery, heating to 220 degrees is required, which necessitates steam of a higher pressure – 0.6 Mpa may not be sufficient.
Ours uses 40 kilograms of steam to heat it to 230 degrees