دانلود رایگان مقاله انگلیسی مسائل مقیاس پذیری و تکنولوژی های کنترل در عملیات صنعتی - الزویر 2018

ABSTRACT

Calcium and magnesium ions are the major components of scaling in different water sources, especially seawater. Calcium and magnesium scale causes problems in various industrial operations such as reverse osmosis unit, heating unit of multi-stage flash distillation, concentration operation of copper-molybdenum mining industry, cooling water system of power generation industry, and water injection operation of oil and gas production. In general terms, scaling affects the operation performance that leads to increased production, as well as maintenance costs. The pH control, scale inhibitors, and nanofiltration membrane have been implemented by industrial operations to control scale. However, the drawbacks of these technologies may force to seek alternative technologies which could be potential alternatives for scale control. This paper discusses the problems of calcium and magnesium scale affecting various industrial operations when seawater is used. It presents current technologies for scale control such as pH control, scale inhibitors, and nanofiltration. Moreover, the technology assessment (TA) was made to evaluate existing and emerging scale control approaches in the case of reverse osmosis (RO) process. The identification of the emerging technologies of scale control has been performed using bibliometric analysis. The comparison of the technologies was made using House of Quality (HOQ) matrix. The identified emerging technologies are: bioelectrochemical system, biomineralization, biosorbent, microbial desalination cells, step by step deposition and extraction technique, carbon dioxide as a precipitator, gas hydrate, ultrasonic crystallization, and capacitive deionization. The comparison of the technologies has shown that nanofiltration, as a common technology, could be an appropriate approach to ensure feasibility and efficiency of RO process, while emerging technology, microbial desalination cells, could become a potential alternative in the future.

Conclusions

In this paper calcium and magnesium scale problems occurring in different industrial processes which use seawater were presented. The RO unit, heating unit of MSF, concentration operation of the copper-molybdenum mining industry, cooling water system of power generation industry, and water injection operation in oil and gas production are industrial operations affected by scale formation. The CaSO4, CaCO3, CaF2, Ca3(PO4)2, Mg(OH)2 and MgCO3 salts are the main components of 559 scale present, with calcium and magnesium ions as the most common species in scaling problems when seawater is used. Independently of industrial operations affected, the scale is formed because operating conditions generate an environment that favours initiating scale formation and its growth. Moreover, a technology assessment to evaluate existing and emerging scale control technologies was performed based on a bibliometric analysis and HOQ matrix for RO process. The pH control, scale inhibitors and nanofiltration membrane are the current technologies used to control calcium and magnesium scale. Whereas, the layer by layer chemical deposition technique, biosorption, carbon dioxide as a precipitator, bioelectrochemical system, microbial desalination cells, gas hydrate, biomineralization, ultrasonic crystallization, and capacitive deionization are emerging scale control technologies. The pH control, scale inhibitors, nanofiltration membrane and microbial desalination cells were the technologies evaluated applied the HOQ matrix. The corrosion, biofouling, environmental impact, energy consumption and technical maturity were customer attributes evaluated for each technology, with energy consumption and environmental impact being the main challenges for RO process. NF technology could be the suitable current option to RO process because it meets with almost all customer needs such as corrosion, biofouling and technical maturity. However, it is necessary to implements solutions to reduce energy consumption and to mitigate the discharge of brine into the marine environment. Whereas, microbial desalination cells could become a potential alternative for scale control in the future due to its energy efficiency and environmental advantages. However, further studies are needed as well as full-scale to evaluate its performance into RO process.