What are the consequences of not allowing ammonia to be burned in a sulfur furnace?
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This post was last edited by liaifeng at 2018-7-28 07:33 as the title. I checked the information and found the following effects: 1. Incomplete ammonia combustion will react with acidic components in the process gas flow to form ammonium hydrosulfide or ammonium polysulfide crystals, which will block the cooling equipment and pipelines, increase the system pressure drop, and even force the device to shut down. 2. The reaction between ammonia and alumina causes catalyst deactivation, and its by-product nitrogen oxides can cause environmental pollution, and nitrogen oxides have a catalytic effect on the further oxidation of sulfur dioxide, generating sulfur, causing equipment corrosion and catalyst poisoning. Regarding item 1, during the sulfur production process, the temperature before the quench tower exceeds 140°C. Ammonium sulfate salt crystallization requires a temperature below 80°C, so it will not cause clogging of the quench tower. Ammonium sulfate can be dissolved in the quench tower through water washing, so there is no problem of clogging. Am I right? This post was last edited by adsl121 on 2009-4-16 23:53 ]
The presence of ammonia can promote sulfation of the catalyst.
Effect of Ammonia Ammonia in the raw gas is another common problem in sulfur recovery equipment. Generally, the ammonia content in the raw gas should not exceed 3%. The harm of ammonia in the raw gas to the normal operation of the sulfur recovery unit cannot be underestimated. The specific manifestations are:: Before the acid gas enters the furnace, various ammonium salts block equipment and pipelines, affecting the normal transportation of the acid gas. After entering the system, the nitrogen and water produced by burning ammonia are inert components in the Claus reaction, which reduces the sulfur partial pressure and thereby reduces the sulfur yield. Due to the presence of ammonia, the air distribution is increased, the amount of exhaust gas is increased, the amount of sulfur entrained increases, the amount of sulfur discharged from the chimney increases, and the sulfur yield decreases. Incomplete ammonia combustion will react with acidic components in the process gas stream to form ammonium hydrosulfide or ammonium polysulfide crystals, which will block the condenser tube, increase the system pressure drop, and even force the unit to shut down. The reaction between ammonia and alumina causes catalyst deactivation, and its by-product nitrogen oxides can cause environmental pollution, and nitrogen oxides have a catalytic effect on the further oxidation of sulfur dioxide, causing sulfuric acid corrosion, equipment corrosion, and catalyst poisoning. In order to ensure a high conversion rate, the H2S/SO2 ratio in the process gas flow after the furnace should be 2: 1. The oxygen supply in the combustion furnace is incomplete, and the complete combustion of ammonia requires an excess of air. Therefore, the treatment of ammonia-containing gas brings difficulties to air distribution. Treatment of ammonia in raw gas 1. The operation of the sewage stripping device has been strengthened to ensure the quality of sour gas. 2． Strengthen the pretreatment of acid gas and increase the mixing and heating of acid gas pipelines to prevent pipeline blockage. 3． If possible, the ammonia-containing gas and the clean acidic gas should be treated separately. When the acidic gas contains ammonia, the air distribution can be increased and the furnace temperature can be increased. This post was last edited by adsl121 on 2009-4-16 23:53 ]
Sulfur recovery devices are divided into ammonia-burning and non-ammonia-burning devices. The NH3 concentration in the acid gas of a device that burns ammonia can reach about 25%, while the NH3 concentration of a device that does not burn ammonia should usually be controlled below 1%. The device that can burn ammonia has a special burner and the temperature in the reactor should be controlled at least above 1300°C. Otherwise, the residual ammonia content in the process gas (normally should be controlled at 20ppm) will * * Exceeded. If the ammonia burning is incomplete, salt formation in the system (mainly in the condenser and reactor) will be serious, and sometimes the system will have to be shut down for treatment. In addition, if ammonia is not burned well, nitrogen oxides may be produced, which will oxidize SO2 to SO3 and finally sulfuric acid, ultimately aggravating corrosion.
Insufficient burning of ammonia will form ammonium hydrosulfide crystals in the rear system, causing blockage and loss of catalyst activity.； Increase air distribution and affect sulfur yield ； Accelerate the corrosion rate and increase environmental pollution.
Crystallization in the low temperature area blocks equipment and affects the quality of sulfur.
1. Reduce the conversion rate of sulfur； 2. Accelerate the sulfation of the catalyst ； 3. Accelerate corrosion of equipment and pipelines ； 4. Thiamine is formed in the back, clogging the system.
Where are ammonia salts mainly formed? Doesn’t it mean that ammonia salt can crystallize only when the temperature is below 85 degrees?
In what form is ammonia decomposed or oxidized in the sulfur furnace?