Kinetics Study On Hydrolysis And Hydrocarbon Generation Of Mixed Fatty Acid Esters Catalyzed By Natural Minerals At Low Temperature

Fatty acids in immature source rocks are regarded as one of the important precursors ofimmatureoil fortheprocessofhydrocarbongenerating.Ithasbeenfoundthatthemainformsof the fattyacids existingin nature are fattyacid esters and practicallyfattyacids of differentcarbonnumberaremixedwitheachother.Choosingthemixtureoftetradecanoic acidmethylester, palmitic acid methyl ester and methyl stearate as the model reactant catalyzed by fiverepresentativenatural mineralssuchas dolomite,calcite,Ca-montmorillonite,illiteandpyritewhich extensively exist in immature source rocks, this paper researches on their hydrolysisand hydrocarbon generation from the mixed fatty acid esters in the presence of the fivenatural minerals at low temperature. The main content of the study include: Research ontheeffect that various inorganic salts influence the hydrolysis andhydrocarbon generation ofthemixed fatty acid esters in the presence of natural minerals at low temperature; Evaluation ofthe activities of different natural minerals for hydrolysis and hydrocarbon generation of themixed fatty acid esters in the presence of different inorganic salts; Kinetics study on theirhydrolysis and hydrocarbon generation from the mixed fatty acid esters in the presence ofnatural minerals at low temperature, obtaining various kinetics parameters including thereaction order, rate constants, the activation energies and the pre-exponential factors bymeans of many kinetics experimental data; Calculation of the life of hydrocarbon generatingfromthemixedesters catalyzed bynaturalmineralsatdifferent temperaturein geologyonthebase of the research of kinetics. Choosingmethyl stearate as the model reactantcatalyzed byfive representative carbonate minerals such as dolomite, calcite, aragonite, siderite andrhodochrosite, this paper preliminary researches reaction mechanism of hydrolysis and hydrocarbon generation from fatty acid esters in the presence of carbonate minerals at lowtemperature and attempts to put forward the reaction course. The experimental resultsindicate that various inorganic salts can influence the hydrolysis and hydrocarbon generatingreactionofthemixedfattyacidestersmoreorless.Inthepresenceofdifferentinorganicsalts,the activities of different natural minerals for hydrolysis and hydrocarbon generation of themixed fattyacid esters are also different. The catalysis of minerals isreflectedbyinfluencingreaction activation energies and pre-exponential factors by kinetics research. The study alsosuggests that both the hydrolysis and the hydrocarbon generating reaction are first orderchemicalreaction.