Modification of dispersed systems and its effect of the internal corrosion of hydrotransports

. Studies The impact of the modification of dispersed systems of kinematic and dynamic parameters of hydraulic windows, as well as wear in pressure pipes, taking into account the variability of the mechanical composition and the number of hydraulic windows. It is recommended for the modifying additives of the GosIpol resin for dispersed systems and its movements in the cylindrical pipes. The current model that takes into account the concentration of turbidity in the stream and the structural composition of dispersed systems, developed methods of calculation in the process of hydrotransport of modified dispersed systems. The method of calculating the rate of internal corrosion of hydrotransports, specific pressure losses for fluid and solid flow and the effect of variability of the mechanical composition of particles and concentration of turbidity to the flow rate and power of the modified dispersion system is justified, the dependence of the hydraulic friction coefficient from the flow movement mode, taking into account the variability of the solid flow concentration in modified dispersed systems of hydrotransport.


Introduction
In the mining and chemical industries, pressure pipelines are used for hydrotransport [1,2]. To increase their performance and durability of one of the most important tasks, the creation of methods for modifying dispersion systems and calculation, in relationship with the physicocheic-mechanical properties of the phases of the system, the composition of dispersed systems, their viscosity [3,4]. Research work aimed at developing energy-saving methods when ensuring hydrotransport of dispersed pressure pipes, as well as new methods and technologies to improve the methods of transmitting dispersed systems through pipelines, taking into account their concentration, mechanical composition and structure in mining and mining and chemical industry, water management and construction [5,6].
In the problem of hydrotransport of dispersed systems through pressure pipes, the main hydraulic parameters are the wear of the material, the pressure loss and the critical flow rate. Currently, the high energy intensity of the hydrotransport systems used in production, in particular, in the mining and chemical industries, construction, water management, is one of the main factors of the low efficiency of their functioning [7,8]. The essence of this process is determined by the peculiarities of dispersed systems, primarily, the particle size composition of solid particles and their volume concentration. The mutual influence of fluid and solid particles during their joint movement is detected by the wear of the pipeline materials, a kind of pressure loss and the determination of the bearing stream capacity [5][6][7][8][9]. The particle size distribution composition of solid particles of dispersed systems, as well as their concentration and modification, have an influence as a change in the average flow rate and as a result of the change in the hydraulic and energy parameters of the pressure system [4][5][6][7][8][9][10][11][12].
Modification of dispersed systems can be carried out at the hydrotransport stage using low molecular weight organic materials and recycled products. Modification of dispersed system-process, in which the composition based on a liquid polymer binder penetrates into the pores and capillaries of particles of dispersed systems. For modification, solutions, dispersion and melts of thermo-and react plates, dispersions and solutions of elastomers, as well as some monomers, oligomers of secondary productions are used. In order to improve the wettability of materials in the impregnating composition, surfactants are introduced. The introduction of nonhanogenic surfactants in an amount of 0.5-3% facilitate the hydrotransport of dispersed systems. The surfactant contributes to the effective dispersion of their particles, an increase in the speed and degree of hydrotransport, the service life of the aggregates and pipelines, the gerence of hydrotransport costs [2][3][4][5][6][7].
In the light of the embezzlement of this study, there is a modification of dispersed systems to improve the method of calculating the kinematic and dynamic parameters of hydraulic windows, as well as wear in pressure pipes, taking into account the variability of the mechanical composition and the number of hydraulic windows.

Research methods
The paper uses standard methods and devices such as IR spectroscopy, viscomemetry, methods for the study of hardness, adhesion, tribotechnical properties of dispersed systems, and also used experimental, field-observational and generally accepted hydraulic methods, drawing up mathematical models based on hydromechanics laws, together with Topics, mathematical statistical methods in the processing of experimental data.

Results and discussion
The weak link in the mining and chemical industry, for hydrotransport of dispersed systems, up to 90% of the total number of damage to which is accounted for by corrosion. Due to the use of recently hermetically isolated on the side of the structures, the duration of the troublefree operation of the hydrotransport of dispersed systems is determined by corrosion of the inner surface and the pumping of the steel pipe pumps. The calculation of the values of the corrosion rate of such sites will allow them to estimate their service term of the τt year, in order to predict planned repairs by equation (1) where Sorg and Ss -Accordingly, the thickness of the pipe wall on the sortiment and calculated according to the strength characteristics, mm (at present, when determining the Ss value, the supply of corrosion is not provided); K -the speed of the internal corrosion of the pipe, mm / year; W, -local corrosion factor, dimensionless value. To date, an important task is to create a calculated methodology for estimating the intensity of corrosion of hydrotransport of dispersed systems, taking into account the characteristics of the metal of heat lines, water-chemical, hydrodynamic and temperature coolant temperature. The complexity of solving this problem is explained by a plurality of parameters affecting a corrosion process, a large zone of their uncertainty associated with a significant length of heat transport systems, fluctuation of the concentration of chemical corrosion reagents, electric currents, chemical composition of pipe material, etc.
Earlier [13][14][15] presents the mechanisms of internal corrosion in hydrotransport dispersed systems and the output of the formula, according to its speed. The calculation gives the parameter value to several times lower than in real conditions of operation of the hydrotransport, probably due to lower solubility values of the Cm, kg/m 3 , magnetite obtained in laboratory conditions, and violations of the water-chemical mode in dispersed systems. Moreover, this difference increased significantly with an increase in the inner diameter of di of hydrotransport.
To increase their performance, one of the methods is a modification of dispersed systems with low-molecular organic compounds. As a modifier, the State Phase resin is chosen by secondary raw materials of little fat production. Polyphenols, fatty acids, hydrocarbons, nitrogen and phosphorus-containing compounds, as well as the transformation products of the State Psycho, are present in the composition of the State Person. Its appearance is visco-fluid mass, color -from a dark brown to the black, acid number of KOH -50-100 mg, the ash content is 1.0-1.2 wt.%, moisture content and volatile substances -up to 4-6%, solubility in acetone-70-80 wt.%, Specific weight 3-0.98-0.99 g/cm, The number of coeximensions of KOH -80-130 mg [2,5,7].
The work was used by the State Pharmaceutical resin of oil and waged complexes, obtained by distillation of fatty acids at a temperature of 220-2300c, containing in its composition from 40 to 50% of condensation products, polymerization and state-line interaction products. Modified dispersed systems formed in the Metallurgical Combine 1% gosypol resin. To do this, in the model (1) it is proposed to enter the function q (di). Therefore, in this paper, a refined method of calculating the internal corrosion of the pipes of hydrotransports made from carbon steel grade 20 is also proposed. Also, for the convenience of calculations on the PС in the procedure under consideration, the approximating functions of Cq (t, pH) of the solubility of magnetite from the temperature f and hydrogen indicator pH are integrable dispersed systems, as well as its density ρ(t) and viscosity µ(t). Considering the above, the rate of internal corrosion can be assessed by the following formula: where βcoefficient recalculation m/s in mm/year; q -coefficient depending on the parameter di; рs, -density of steel arising on the inner surface, kg/ m 3 ; θporosity of the dense layer of magnetite, pipes, shares; k is the rate of corrosion reaction at the metal -oxide border, m/s; χ is the proportion of magnetite in corrosion products (χ = 0,5 for the normalized oxygen concentration in the heating system); h is the thickness of the dense layer of magnetite, m Cm (t, pH)=ρ(mt2-nt+p)*10-9 (5) where t, n, p -coefficients taken for different temperature ranges and pH values from the data below: The dependence of the Cm(t, pH) for the hydrotransports characteristic pH in systems is presented in Fig. 1. The representation of the experimental data of the Cm in the form of equation (8) allows you to implement the computational algorithm on the PC. The results of the calculation of the velocity (K) of the internal corrosion according to the above procedure are compared with the values found by the gravimetric method (on the loss of metal mass during operation) during the survey of the hydrotransports of dispersed systems.
For this, samples from hydrotransports (steel 20) were cut on various emergency (due to corrosion) sections. The overwhelming majority of metal damage as a result of internal corrosion occurs on supply hydrotransports, so the samples were taken from such pipes. The outer corrosion of the selected hydrotransports is insignificant, therefore, the weight loss of the metal pipe from the outside is extremely small, which made it possible with the help of a gravimetric method to challenge the rate of internal corrosion.
The calculation of the rate of internal corrosion by substitution to the calculated formulas of values of τt, t, pH, h, di, G corresponding to the working conditions of the surveyed areas. The values of the parameters T, the pH was taken as the average per year, and the G value remained constant during the entire period of operation. The average annual calculated values of the parameter K are in the range of 0.01 -0.07 mm/year.
The nature of the change in the internal corrosion rate in the range of 8.0 <pH <10.0 at the average annual temperature of the modified dispersed systems 20 ° C is shown in Fig. 2. Corrosion rate at normalized values pH = 9.6 -10.0 is almost equal to zero and exponentially grows with a decrease in the pH.
The calculation according to formula (2) gives an estimate of the intensity of uniform wear of the hydrotransports. However, in real conditions of operation of hydrotransports at pH <9.5 corrosion of carbon steel pipes, a local character is wearing a local character (the reasons are the increased content of Cland ЅО4 2-, ions, the heterogeneity of iron oxide films on the surface of the steel and the presence of pairs of uneven aerations, non-metallic inclusions and dislocations). It is the local corrosion that is the main cause of emergency stopping of the portions of hydrotransports.

Conclusions
As a result, the modifying additives of the GosIpol resin for dispersive systems and its movements in the cylindrical pipes The current model, which takes into account the concentration of turbidity in the stream and the structural composition of dispersed systems, developed methods of calculation in the process of hydrotransport of modified dispersed systems. The method of calculating the rate of internal corrosion of hydrotransports, specific pressure losses for fluid and solid flow and the effect of variability of the mechanical composition of particles and concentration of turbidity to the flow rate and power of the modified dispersion system is justified, the dependence of the hydraulic friction coefficient from the flow movement mode, taking into account the variability of the solid flow concentration in modified Dispersed systems of hydrotransport.