{'fraction_non_alphanumeric': 0.018741323461360482, 'fraction_numerical': 0.015733456732993985, 'mean_word_length': 4.810483870967742, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Equipment for paraffin removal from oil pipelines in order to ensure energy saving in Arctic conditions

The paper describes a new method for solving one of the global problems – paraffin rempval from pipelines. The problem is relevant for all oil producing and transporting companies of the Russian Federation and other countries. The method for solving these problems has several advantages, including duration of the overhaul period, high removal efficiency and profitability due to the use of fuel cells. The methodallows for maintaning a constant temperatures equal to the melting point of paraffin.


Introduction
Today, a decrease in operating costs of paraffin deposit removal and prevention which are seasonal in nature and reach 60 % or more in the autumn-winter periodis a crucial task of the oil industryin arctic conditions [1,2]. With these high costs, the performance of the paraffin cleaning devices in arctic conditions is no more than 10 km per day. In this regard, new methods which are cheaper and more technologically efficient are being studied [3].
Since the oil pipelines are mounted above the ground on concrete pylons, they are highly susceptible to seasonal fluctuations at temperatures varying from -50 to 50 °C. The lack of effective heat insulating coatings on the outer surface of oil pipelines leads to an abnormal increase in the rate of paraffin deposit formation on their inner surface which makes the cleaning process much harder and reduces the performance of cleaning devices, especially in autumn and winter [4,5].
Analysis of the efficiency of devices used for cleaning the internal surface of oil pipelines is presented in figure 1. It shows that there is no alternative to thermal and scraper-type devices provided that the source of thermal energy is autonomous and has a large working life which is sufficient to service large spans between pumping stations up to 100 km. A fuel cell can be used as a source of thermal energy with a large working life. A fuel cell is a chemical current source or an electrochemical generator for converting chemical energy into electrical one.

Materials and methods
Sulfuric acid is used as an electrolyte in the fuel cell, and hydrogen is used as a fuel which is combined with oxygen in the oxidizer. As a result of the chemical reaction, hydrogen and oxygen are converted into electricity [6,7]. As a result of this process, water is formed and a large amount of heat is released.

Method of application
Under pressure developed by products 2, the technological projectile consisting of two containers (heat-generating container 3 and scraper-mechanical container 4 connected with cardan hitch 5) moves inside main pipeline 1 (Figure 2). Both containers are held on the axis of the main pipeline by wheel centralizers 6 and are driven by the hydraulic resistance of the transported product using elastic cuffs 7 which cover the gap between containers 3,4 and the inner wall of pipeline 1. During the axial movement of technological containers 3 and 4, the inner wall of main pipeline 1 is cleaned from paraffin softened by heat generating container 3 [8,9]. When moving along the axis of main pipeline 1 of the technological system consisting of heat generating container 3 and scraper-mechanical container 4, counter-flow 12 of transported product 2 flows into container 3 through holes 10 on its front surface, washes the walls of fuel cell battery 9 through which hydrogen contained in the transported product enters the fuel cells and heats them due to the decomposition into protons and electrons. Then, the product heated to a certain temperature which is higher than the paraffin crystallization temperature (≥25-30 °C) and transported through holes 11 on its rear surface 13 washes the inner wall of main pipeline 1 and softensparaffin [10,11].

Conclusion
The equipment described in this article reduces labor intensity of maintenance per 1 km of the main pipeline, eliminates the need for supplying power lines, reduces consumed electrical power by using fuel cells as power sources using atomic hydrogen as a fuel contained in the transported products, and contributes to high performance with a long-range of up to 100 km or more, a high failure interval of up to 50 hours and a small payback period of up to 1.5-2 years or less.