Investigation For The H₂S Removal Existed In Petroleum Associated Gas Of Offshore Drilling Platform By The Method Of Seawater Improved LO-CAT

Petroleum associated gas is a kind of high quality energy in the chemical industry.H₂S impurities which contain in petroleum associated gas not only corrode pipelineequipment, pollute drilling fluid, cause catalyst poisoning, but also harm people’shealth seriously. Therefore, the removing of H₂S is an effective way to purifypetroleum associated gas and produce clean energy. In view of the high security ofoffshore drilling platform, which is far away from the coastline and whose volumeand bearing capability are limited, the absorbing medium to remove H₂S is the best tochoose safe and inexpensive solvent in the surrounding environment. Obviously,seawater which has strong buffering capacity and natural alkaline is the best choice.A set of new LO-CAT desulfurization device which separate regeneration fromcatalytic oxidation desulfurization is retrofitted based on the basis of earlyexperiments. Air used for regeneration is divided into two strands which enter intocatalytic oxidation desulfurization system and regeneration system respectively. Smallflow of air into catalytic oxidation desulfurization system can oxidize Fe2+L whichhave just been reduced partly to Fe³⁺L rapidly. It can accelerate the desulfurizationefficiency. And oxygen and nitrogen content of petroleum associated gas afterpurification is lower to avoid some problems such as calorific of petroleum associatedgas reduction and explosion. Large flow of air into regeneration system empty afterregeneration. It won’t cause above-mentioned problems as well.The removal of H₂S through seawater in this new LO-CAT desulfurizationdevice by chelated iron is studied. Firstly, the effects of parameters in regenerationsystem and catalytic oxidation desulfurization system on the removal of H₂S （10g/m³）which exists in the simulated petroleum associated gas from marine drilling platformare investigated. Secondly, the desulfurization effects of other formula solutions are studied under optimum conditions obtained in front, and compared with the formulasolution C in order to obtain the best desulfurization formula. Finally, the solidproducts of desulfurization and formula solutions are characterized by relevantmethods.The results show that, in formula solution C through seawater, when solutionvelocity is8.77mL/min, absorption temperature is25℃, regeneration temperature is45℃, air excess factor is90, the initial pH value of the solutions keeps8and theinitial concentration of Fe³⁺maintains0.005mol/L, the optimum catalytic oxidationdesulfurization and regeneration conditions for H₂S removal can be obtained. Thedesulfurization efficiency of formula solution1is best because of the longestbreakthrough time which reaches680min and the biggest liquid phase sulfur capacitywhich is about9.8546g/L, extended50%and74%respectively when comparing withformula solution C, under the same conditions of process and initial concentration ofFe³⁺. The characterization results by SEM, XRD, FT-IR and chemical detection showthat the solid products produced in formula solution C are rhombic sulfur and it isbeneficial to recover sulfur because of high purity. It may contain high concentrationsof polymer alcohols, carboxylic acids, esters or amine compounds in formula solution1to improve the desulfurization efficiency. However, its solid products have manyimpurities, so it is bad for sulfur recovery. The desulfurization efficiency of formulasolution2-8is not ideal and the solid products are not suitable for recycling.