Estimation of evaporative losses during storage of crude oil and petroleum products

Abstract

Storage of crude oil and petroleum products inevitably leads to evaporative losses. Those losses are important for the industrial plants mass balances, as well as for the environmental protection. In this paper, estimation of evaporative losses was performed using software program TANKS 409d which was developed by the Agency for Environmental Protection of the United States US EPA. Emissions were estimated for the following types of storage tanks: fixed conical roof tank, fixed dome roof tank, external floating roof tank, internal floating roof tank and domed external floating roof tank. Obtained results show quantities of evaporated losses per tone of stored liquid. Crude oil fixed roof storage tank losses are cca. 0.5 kg per tone of crude oil. For floating roof, crude oil losses are 0.001 kg/t. Fuel oil (diesel fuel and heating oil) have the smallest evaporation losses, which are in order of magnitude 10-3 kg/tone. Liquids with higher Reid Vapor Pressure have very high evaporative losses for tanks with fixed roof, up to 2.07 kg/tone. In case of external floating roof tank, losses are 0.32 kg/tone. The smallest losses are for internal floating roof tank and domed external floating roof tank: 0.072 and 0.044, respectively. Finally, it can be concluded that the liquid with low volatility of low BTEX amount can be stored in tanks with fixed roof. In this case, the prevailing economic aspect, because the total amount of evaporative loss does not significantly affect the environment. On the other hand, storage of volatile derivatives with high levels of BTEX is not justified from the economic point of view or from the standpoint of the environment protection.

Skladištenje nafte i naftnih derivata neizbežno dovodi do pojave evaporativnih gubitaka, koji su važni sa stanovišta odgovarajućeg bilansa i sa stanovišta zaštite životne sredine. U radu je izvršena kvantifikacija evaporativnih gubitaka za različite tipove komercijalnih rezervoara sa fiksnim i plivajućim krovovima korišćenjem softverskog programa TANKS 409d. Na osnovu rezultata procenjene su mase evaporativnih gubitaka po toni uskladištene tečnosti. Gubici sirove nafte za rezervaore sa fiksnim krovom iznose oko 0,5 kg/t sirove nafte, a za rezervoare sa plutajućim krovom oko 0,001 kg/t. Gubici dizela i mazuta su zanemarljivo mali, iznose do 10-3 kg/t. Najznačajniji gubici isparljivih tečnosti su u rezervoarima sa fiksnim krovom (do 2,07 kg/t), a najmanji gubici su kod rezervoara sa kupolastim krovom (oko 0,004 kg/t). Predmetni rezultati predstavljaju osnovu za analizu problema sa tehnoekonomskog stanovišta i sa stanovišta zaštite životne sredine, u funkciji projektovanja.