Hydroxyl carboxylate based non-phosphorus corrosion inhibition process for reclaimed water pipeline and downstream recirculating cooling water system

Abstract

A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies (PRWS) and in downstream recirculating cooling water systems (RCWS) using the reclaimed water as makeup. Hydroxyl carboxylate-based corrosion inhibitors (e.g., gluconate, citrate, tartrate) and zinc sulfate heptahydrate, which provided Zn 2+ as a synergistic corrosion inhibition additive, were added prior to the PRWS when the phosphate (which could be utilized as a corrosion inhibitor) content in the reclaimed water was below 1.7 mg/L, and no additional corrosion inhibitors were required for the downstream RCWS.Satisfactory corrosion inhibition was achieved even if the RCWS was operated under the condition of high numbers of concentration cycles. The corrosion inhibition requirement was also met by the appropriate combination of PO 4 3− and Zn 2+ when the phosphate content in the reclaimed water was more than 1.7 mg/L. The process integrated not only water reclamation and reuse, and the operation of a highly concentrated RCWS, but also the comprehensive utilization of phosphate in reclaimed water and the application of non-phosphorus corrosion inhibitors. The proposed process reduced the operating cost of the PRWS and the RCWS, and lowered the environmental hazard caused by the excessive discharge of phosphate. Furthermore, larger amounts of water resources could be conserved as a result.

Effect of phosphate availability on biofilm formation in cooling towers

“…Its limitation has been shown to induce greater EPS production by the cells and to result in a homogenous structural deposit, detrimental for full-scale processes. Total removal of phosphorus from a water source is hardly achievable, and phosphorus-based corrosion inhibitors would have to be replaced by phosphorus-free products for the protection of the heat exchangers (Sandu et al 2016;Wang et al 2016). The intensive contact between water, ambient air and particles in the CT as well as evaporation are all factors that can also raise the element concentration in the system (Mahowald et al 2008;Katra et al 2016).…”

Analysis of Microbial Community in Circulating Cooling Water System of Coal Power Plant during Reagent Conversion

“…In numerous regions globally, the law restricts high levels of inorganic phosphates [14]. The use of phosphorous scale inhibitors can exacerbate calcium phosphate deposition in circulating cooling water, presenting additional challenges [15]. Consequently, the increase in use of biocides has sparked a major scientific debate [16].…”

An investigation on scaling failure of heat exchanger in cooling water system of natural gas purification plant

“…In the heat exchange process of a natural gas purification plant, the circulating water as a cold fluid medium is generally used in many heat exchangers; therefore, the issue of scaling in the circulating water system has aroused widespread concern. 15,16 Commonly, the circulating water system is composed of cooling tower, circulating water pump, pipeline, heat exchanger, and the likes. 17 The mechanism for scaling in circulating water system is extremely complex, especially in an open system of which the composition of water is constantly changing every day.…”

“…Generally, scaling frequently occurs on the metal wall on one side of the heated fluid. In the heat exchange process of a natural gas purification plant, the circulating water as a cold fluid medium is generally used in many heat exchangers; therefore, the issue of scaling in the circulating water system has aroused widespread concern 15,16 . Commonly, the circulating water system is composed of cooling tower, circulating water pump, pipeline, heat exchanger, and the likes 17 .…”