What is the composition of the scale formed after desulfurization of natural gas with high hydrogen sulfide content? How to clean it?
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The natural gas collected from gas fields contains high levels of the toxic gas hydrogen sulfide. After desulfurization of hydrogen sulfide, scale forms on the inner walls of the equipment and pipelines as a result of their long-term operation, which has a significant impact on the volume of natural gas that can be transported. What is the composition of this scale on the inner walls? Is it pure sulfur, or dirt that is primarily composed of sulfur with other polymers mixed in? How should elemental sulfur be dissolved? How should dirt composed mainly of sulfur scale with other polymers mixed in be dissolved? For safety reasons, it is best to use non-toxic chemicals. I hope those who are knowledgeable can offer some guidance.
It is mainly deposits of iron sulfide and oilfield chemicals, which can be resolved through pigging.
Reply to 2# cenzh008864: To add more details, it refers to the collection pipes within the gas gathering station, as well as vessels and equipment such as heaters and separators. The pipeline distances are too short and there are too many bends, making it impossible to clean the pipelines.
This situation should be rare; first, it is necessary to strengthen pipe cleaning, and second, additives for clearing blockages can be used following the practices employed for wellhead management.
Reply to 4# cenzh008864: This situation already exists in the gas gathering stations of the Puguang Gas Field; pigging can be used to address it in long-distance pipelines； But the inner walls of the pipelines inside the station are a bit more challenging. Firstly, because of the current cleaning technologies, plant cleaning requires shutdown of operations. Secondly, all the equipment and pipelines, control valves, and instruments in the plant are imported; therefore, during cleaning it is necessary to minimize the disassembly of such components as pipelines and valves. Finding a way to clean a natural gas plant without shutting down operations is a new challenge.
Reply to 5# li*uqi2008: Natural gas from Puguang has a high hydrogen sulfide content, which may lead to the deposition of elemental sulfur. If elemental sulfur is indeed present, similar issues should occur in the wellhead separator as well. The Natural Gas Research Institute in Southwest China conducts specialized research on sulfur solvents; you can consult them.