International Journal of Engineering Research and Reviews
ISSN 2348-697X (Online) Vol. 8, Issue 4, pp: (26-32), Month: October - December 2020, Available at: www.researchpublish.com
EFFECTS AND REMEDIATION OF WAX IN OIL PIPELINE AND EQUIPMENT USING A SAMPLE OF NIGER DELTA CRUDE OIL Peter Edimeh1, Mukhtar Abdulkadir2 1,2
Department of Chemical Engineering, Federal University of Technology Minna, Niger State, Nigeria.
Abstract: In the petroleum industry, still a major problem is the deposition of paraffin wax especially during exploitation in Deepwater field. This study is aimed at characterizing crude oil sample, understanding the characteristic of paraffin wax and testing the solubility of the precipitated wax in xylene and kerosene at different blend ratios. The crude oil sample which was obtained from Eleme community in Niger Delta, Nigeria, was characterized and the cloud point and pour point were obtained as 20 oC and 12oC respectively. Results obtained from the solubility test shows that 100% Xylene dissolves 99.4% of the precipitated wax in 150 min and 90.1 % in 90 min. While for same quantity 100% kerosene shows solubility of 35.4% in 150 min and 26.2% in 90 min which implies that xylene although expensive is a better solvent for paraffin wax cleanup when compared to kerosene. At different xylene – kerosene blend ratios, the blend of 70:30%, Xylene: Kerosene mixture also gave an excellent result, far from the one obtainable in the 50:50%, and in very close proximity with the 80:20% blend. This indicates that Kerosene which is cheap and readily available when blended with xylene, an excellent solvent can be used on an industrial scale for the cleanup or dissolution of wax deposit in a cost effective and efficient manner. Keywords: Wax, Paraffin, Chemical, Remediation, Eleme, Xylene, Solvent, Pipeline, Deposition.
I. INTRODUCTION The petroleum industry is still bedeviled by complications arising from the deposition of paraffin wax on the inner walls of production and transportation pipelines. At reservoir condition, paraffin wax is a soluble constituent of crude oil at equilibrium, however, as condition changes along the production lines, these paraffin wax can crystallize and form thick layers on the wall of production equipment. Most crude oils contain some amounts of wax and paraffin, as a hydrocarbon, wax contains 20 to 40 carbon atoms in a chain that consists of different structural types such as straight-chain, branchedchain and cyclic chain, and aromatic hydrocarbons [1]. Wax molecules can change its structure from linear or branching to cyclic form as well as aromatic hydrocarbons in the presence of other cyclic hydrocarbons [2]. This dynamic behavior can have an effect on the melting point and the solubility of the wax [3]. This problem can be solved by the study of the effect of some parameters on the precipitation of wax [4]. Paraffin wax is a colorless and odorless solid at room temperature, thus making it easy to determine the formation of wax in crude oil samples [5]. The formation or precipitation of wax is caused by factors such as the reduction of temperature of the crude oil during the transportation of the oil along pipelines from the rig to the shore [6], the flow rate at which crude oil is transported; low flowrates leads to a higher chance of wax precipitation as there is a greater number of particles available for deposition under a laminar flow regime. Also, the severity of this wax deposition challenge depends on the type of the crude oil transported and the composition of the formed wax; straight-chain compounds easily crystallize while the cyclo-paraffins (naphthene) do not tend to crystallize and deposit on surfaces easily. Controlling and remediating wax depositions is still one of the critical challenges in oil and gas industries as the industry explores in increasingly challenging environments, such as deepwater and subarctic conditions based on remarks of Simon Richard, SPE, who is the Principle Consultant for EP Consult. The deposition of paraffin wax causes major problems such as flow rate reduction, complete flowline blockage, increase in pumping power, reduction in production output, decrease in equipment performance [7, 8, 9], and ultimately increase in the cost of production [10].
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