| With the rapid development of economic and society, and the continuous development of the chlorine and bromine based fine chemicals, the demand for brine resources increased rapidly. But after the continuous mining, shallow underground brine resource cannot satisfy the needs of the development of industry. As a result, deep underground brine resources caused wide attention. Compared with the exploitation of shallow underground brine, mining deep underground brine cost more in the process of exploitation and operation, and the eroding problem influenced seriously the work of mining brine, because the high salt, high temperature and high pressure problem. Therefore, seeking a technology to control corrosion problem is of great significance, which can improve mining halogen process throughput and reduce the energy consumption and economic cost.The Yellow River delta deep brine was selected as the studied object in this paper. In order to study the technology to control corrosion problem during the process of mining deep brine, on the basis of the comprehensive research of literature, through studying the corrosion mechanism of carbon steel equipment in brine, screening hypersaline brine resistant metal materials, researching hypersaline brine resistant surface anti-corrosion technology, a hypersaline brine resistant surface anti-corrosion technology was investigated. The anti-corrosion technology was used in the process of mining deep brine, and satisfied results were obtained. The main contents and results are as follows:(1) The influences of time, temperature, salinity, pH, pressure on the corrosion rate of N80 steel in brine was studied. Results show that:with the time increasing, a corrosion layer on the surface of N80steel was formed and the corrosion rate reduced gradually in high temperature and hypersaline brine; the corrosion rate of N80steel increased with the temperature rising, and the corrosion rate of 100℃ increased 18.42times than 20℃; with the increase of salinity, the corrosion rate of N80steel rose first and then fell under 40℃ in brine; the corrosion rate of N80 steel increased with the pressure increasing, the corrosion rate at 60℃ and normal pressure was 0.2133 mm/a, the corrosion rate at 10MPa was 0.6333 mm/a, which increased 1.97 times than that at normal pressure; when the pH range of hypersaline brine at 5.0～7.0, the corrosion rate of N80 steel changed little, floating in the vicinity of 0.1 mm/a.(2) With the problems of extraction equipment severe corrosion problems, corrosion test was applied to compare the ability of corrosion resistance of N80 steel,7075 aluminum alloy,2024 aluminum alloy, Q235 steel,20# steel, lCrl3 steel, duplex stainless steel 2205, stainless steel 316 L and stainless steel 304. Results show that the corrosion resistance of material order was duplex stainless steel 2205> stainless steel 316L>stainless stee1304>1Cr13 stee1>N80 steel> 20# steel ≈ Q235 steel ≈2024 aluminum alloy> 7075 aluminum alloy in the brine of 267.2 g/Lat the temperature of 95℃.(3) Ni-W-P plating was prepared on the N80 steel substrate by electroplating deposition. By studying the influence of current density, pH of electrolyte solution and temperature on the corrosion resistance of electro-deposition of Ni-W-P coating, the best technological parameters was obtained; current density of 8 A/dm2, pH=6 temperature at 60 ℃. The performance test of electro-deposition Ni-W-P plating was carried out by characterization and analysis test method of SEM, XRD, EDS, electrochemical and full immersion corrosion test. Results show that, the corrosion rate of electro-deposition Ni-W-P plating on N80 steel reduced to 21% compared with N80steel in the brine at 90℃.(4) Ni-W-P plating was prepared on the N80 steel substrate by chemical deposition. By studying the influence of concentration of plating solution such as nickel sulfate, sodium tungstate, sodium hypophosphite and sodium citrate on the corrosion resistance of electroless plating Ni-W-P coating, the optimum bath formula was obtained:30g/L nickel sulfate,40g/L sodium tungstate,25g/L sodium hypophosphite, 90g/L sodium citrate. The performance test of electroless plating Ni-W-P coating was carried out by characterization and analysis test method of SEM, XRD, EDS, electrochemical and full immersion corrosion test. Results show that, the corrosion rate of electroless plating Ni-W-P coating on N80 steel reduced to 20% compared with N80steel in the brine at 90℃.(5) The practical application of Ni-W-P plating technology during the brine mining shows that:Brine circulation after 3d in the simulator, the halogen pipe plating Ni-W-P does not appear corrosion phenomenon, and brine composition analysis results show that the anti-corrosion technology has not obvious influence on the quality of brine. The practical application of Ni-W-P plating technology on the halogen pipe about 3months shows excellent anti-corrosion effect in the brine the temperature at 21-40℃, the salt content in 110～330g/L. Therefore, Ni-W-P plating technology as anticorrosion technology on brine pipe is economical and feasible, which can be used for the mining of the Yellow River delta deep brine. |
PDF Full Text Request