I would like to ask the experts: Can flare gas containing 1% hydrogen sulfide be directly discharged into an overhead flare?
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Experts, as the title suggests, can the flare gas from a chemical plant, which contains 1% hydrogen sulfide, be discharged into an elevated flare? When hydrogen sulfide burns, it produces sulfur dioxide, which pollutes the atmosphere. Since this gas contains hydrogen sulfide, it cannot be discharged directly into an overhead flare; therefore, a desulfurization unit needs to be installed before the gas is sent to the flare, or perhaps such a unit should be placed near the flare. I would appreciate it if the experts could help answer this. Thank you!
This post was last edited by Wise Ming on 2020-3-6 09:29. It’s not possible; weakly acidic gases are highly corrosive to overhead flares. An acidic gas torch can be installed within the device, which is cost-effective. The option of adding a desulfurization unit is not advisable; firstly, 1% hydrogen sulfide gas is already quite weak, and the cost of forcing desulfurization is very high ； Second, it generates large amounts of alkaline waste residue and wastewater.
Yes, it is sufficient to ensure that the concentration of combustion by-products at the ground level meets environmental regulations. Attention should be paid to the corrosion requirements for pipelines and equipment; anti-humid hydrogen sulfide treatment may be necessary, which increases costs.
In the absence of a total emission figure, it is generally acceptable; many chemical plants use separate acid gas pipelines for emissions, and blending of gases can also be employed
No, weakly acidic gases are highly corrosive to overhead flares. An acidic gas torch can be installed within the device, which is cost-effective. The option of adding a desulfurization unit is not advisable; firstly, 1% hydrogen sulfide gas is already quite weak, and the cost of forcing desulfurization is very high ； Second, it generates large amounts of alkaline waste residue and wastewater. Support for this solution
This needs to be calculated to determine. Today, the flares in chemical plants are generally used to safely burn and discharge waste gases from various units that have no value for recycling. If the corrosion problem caused by this hydrogen sulfide-containing gas can be resolved or tolerated, and if the amount of this gas discharged into the flare is not large enough to cause the sulfur dioxide levels in the flue gases to exceed permissible limits, then it can be discharged into the flare. This approach is likely to be the simplest and cheapest solution, with no safety or environmental concerns. If calculations show that the introduction of this hydrogen sulfide-containing gas results in sulfur dioxide concentrations in the flue gases exceeding the allowed limits, then it cannot be discharged; otherwise, it can be discharged after adding an appropriate amount of diluent to bring the levels within acceptable limits.
Whether this gas is sent to a torch or burned, it will result in environmental standards being exceeded. For this, the previous set of complexed iron desulfurization equipment is actually the best choice. Direct discharge will definitely exceed the limits. The environmental compliance inspection cannot be passed either. Moreover, hydrogen sulfide also causes severe corrosion to equipment and pipelines. I hope this can help you.
You haven’t conducted any investigations or calculations regarding the total amount; how do you know that it will lead to environmental pollution exceeding limits? If the emissions from this chemical plant account for only a tiny fraction of the total emissions from flares, and the sulfur content in those total emissions is also low, then from a cost perspective, after thorough calculations, it is the most economical option to burn off those emissions directly without any treatment, as long as the limits are not exceeded.
Yes, but the concentration of SO2 at the ground level needs to be taken into account
A comprehensive consideration is needed: the design capacity of the flare system? Is it possible to introduce torches simultaneously (several streams of material)? 1% H2S fire protection depends on the quantity (flow rate) of the material…… The possibility of desulfurizing the material sent to the flare is very low, unless the flow rate of this material is very low. The use of flare materials is generally a safety measure taken in emergency situations to protect equipment. This applies to situations such as valve discharge, high pressure (and even high temperature), large volumes of fluid, and instability – conditions under which it is difficult to install a separate desulfurization system to meet the requirements. It is recommended to evaluate the safety and reliability of the emergency release system.