The use of heavy oil emulsifying bacteria to prevent sedimentation in the pipeline route

Doctoral dissertation in the field of chemical engineering, biotechnology orientation

Abstract

Heavy oil transportation by pipeline is one of the most important and suitable transportation methods, and the high viscosity of heavy petroleum compounds and their sedimentation in the transportation route is the most obvious problem of this type of transportation. Emulsifying heavy oils in water is one of the best ways to solve this problem. In this project, four microbial strains ACO4, ACO1, 91-B and 1072 have been used to produce bio-emulsifiers to form a stable and suitable emulsion. These emulsifiers have been isolated by the growth of strains in the culture medium and suitable conditions, produced and through a multi-step process. By using these materials and carefully implementing the emulsification process, different oil-in-water emulsions were made for all strains and two samples of heavy oil prepared from Nowruz and Soroush oil fields. According to Taguchi's test design model, viscosity reduction and emulsion stability experiments were performed and the ability of these biological emulsifiers to create a stable oil-in-water emulsion was proven. In optimal conditions (35% water, 1.32% emulsifier from ACO4 strain and 45°C temperature), the viscosity of heavy oil samples decreased by 98% and remained stable for 48 hours. This reduction reached 60% after 8 days. Due to the high power of this emulsifier in the emulsification of heavy oil in water, in the second part of this project, this material was used for emulsification on a pilot scale. By forming an oil-in-water emulsion on a semi-industrial scale and creating optimal conditions, the viscosity of the heavy oil sample remained stable for 72 hours after decreasing to cP 830. By passing the produced emulsion through the semi-industrial pipeline and comparing its sedimentation rate with heavy oil, the reduction of sedimentation due to the passage of oil in the form of emulsion is clear. This advantage provides more convenient and less expensive conditions for transporting heavy oil by pipeline.

Key words:

Biological emulsifiers, oil-in-water emulsion, viscosity reduction, sedimentation reduction; Pipeline.

Heavy crude oil and transportation methods

The growing trend of demand for energy around the world, especially in industrialized and developing countries, has highlighted the necessity and role of heavy crude oil production and transportation to meet energy needs. According to the forecast of the International Energy Agency, the world's demand for primary energy will increase by 28% in 2011 and by 60% by 2030, and in other words, the average growth rate of energy demand will be 1.7% per year. The contribution and role of hydrocarbon resources in supplying and covering this growing energy demand is very large and ahead of other energy sources, and the role of heavy crude oil will be more prominent and decisive [1 and 2].

In today's world, more than 60% of human energy consumption is oil products, which is more than 80% in our country. Of the total oil consumption products, about 70% are gasoline and gas, or the so-called light cuts, and the rest are used as heavy (heavy cuts) [2 and 3] [.

According to the statistics and estimates provided, the amount of oil in the world's oil reserves is estimated to be about 6200 billion barrels, of which 1300 billion barrels are crude oil with an API of more than 020, which is so-called They are called light oil. And the rest, about 4900 billion barrels, is heavy oil with API less than 020, which is called heavy oil. But currently, a very small percentage (1 to 2%) of the world's heavy crude oil resources are exploited. As a result of research in the fields of extraction, processing and transportation of heavy oil, while creating high added value, it can increase the amount of accessible reserves and the use of oil and fossil fuels. (Table 1-1)]3-4[.

Due to the high volume of heavy oil reserves in the past few years, the operation of extracting these types of oils has started using common methods in most developed countries and is developing at a high speed. This issue has caused the following views and thoughts to be expressed regarding the use and processing of heavy oil as quickly as possible [2 and 3].

The ability to extract heavy crude oil with the aim of using oil resources as existing latent energies.

The possibility of transferring heavy crude oil to centers and consuming factories and oil refineries.

Creating a factor that can keep the global price of oil stable based on the increase in the number of oil producing countries.

Decreasing the strategic aspect of petroleum products

Delaying the need for large investments to extract and use other fuel sources such as coal and other synthetic fuels [3]

In light of the above, it can be concluded that carrying out heavy oil improvement processes (heavy cuts) according to the new developments of oil-related industries can solve the problem of the lack of light products. solve a suitable limit.

In general, the exploitation of heavy oil, from production to transfer and refining, requires the use of advanced technologies due to its special properties. In addition, due to the gradual increase in the weight of oil in reservoirs and the huge amounts of heavy oil reserves, its production, transportation and processing require special investment and more than the investment required for the exploitation of conventional oil. Currently, many production projects and especially the transportation of heavy oil through pipelines are being implemented in oil-producing countries around the world, which are facing many technical and economic issues and problems. Here, the proposed methods for transporting heavy crude oil by pipeline were analyzed from technical and economic aspects [2 and 5].

The transportation of heavy oil by pipeline is not possible without a previous reduction in its viscosity. The high viscosity of crude oil, part of which is the result of coagulation or precipitation of asphaltene materials with a very large molecular weight, causes severe problems, which include clogging of the well cavity during production and sedimentation operations, and finally blockage in the pipeline during transportation operations. A review of numerous reports shows that the production of heavy oil has been increasing especially since 2000 and it is expected that this trend of increasing production will continue at least until 2020. Therefore, the urgent need for heavy oil as a source of hydrocarbon energy, in order to safely supply the increasing demand for energy in the coming decades, not only requires the development and achievement of effective and economical methods for the transportation of heavy oil by pipeline; Rather, it should be considered as a strategic necessity for an oil-rich country in the internal and international scope [6 and 7]. rtl;">Abstract

Heavy Oil transportation by pipeline is one of the most appropriate methods to transfer. High viscosity oil compounds and depositing them in the transmission path, is the most obvious problem with this type of transfer. Oil in water emulsion formation is one of the best ways to solve these problems. To form a stable emulsion in this project, four new microbial strains ACO4, ACO1, 91-B and 1072 are used to produce biological emulsifier. The emulsifiers have been produced by growing strains in culture and suitable conditions. And they have been isolated and purified by an application process. Oil in water emulsion were formed for all strains and two heavy oils produced from the Soroush and Nuroze oil fields. These emulsions are used to get the best strains and optimal conditions for emulsion formation. Reduce viscosity and emulsion stability tests were performed according to the Taguchi experimental design models. With these experiments, the ability of the biological emulsifier in the formation of stable oil in water emulsion is proven. By the strain (ACO4) and in optimal conditions (35% water, 1.32% emulsifier and 45 oC temperature) the viscosity of heavy oil has been reduced in the initial 48 hours by 98%. After 8 days, this decreased rate has changed to 60%