Use of chlorine for control of biological fouling in power plant cooling water system is the perfect way of controlling bio-fouling at reasonable concentration as chlorine is available within a low cost. Chlorine Gas feeders are simple easy to control at low capital cost and requires minimum maintenance. The chlorine residual for shock dosing can be relatively short and in expensive. De-toxification (dechlorination) systems can be installed at a very nominal cost to satisfy the environmental requirement.
Total residual chlorine (TRC) as expressed in red book of United States of Environmental Protection Agency (EPA) specifies 0.2 mg/litres TRC. It should not exceed 160 minutes all day and night.
Point of chlorine dosing in Sea
Normally the sea water for power plant is taken deep on the sea cruising water intake head. The ocean water travels through intake pipe and reaches the CW pump sump in which the water is pumped to the condenser.
Continuous and Shock dosing chlorination
In Sea water application both continuous and shock dosing chlorination are tried for effective bio fouling.
At sea water intake head of inlet pipe, continuous dosing of around. 1 - 2 ppm tend to be effective accountable for Mollusks, algae, slime and weed. They constrict the flow of Sea water in the intake pipe. It also prevents sea shell deposition your past pipeline the industry most trouble-some to delete.
Continuous chlorine dosing is done near to the pump house ahead of bar racks and traveling water projection screen. 1-2 ppm is recommended therefore the complete bar racks and traveling water treatment screen can be kept neat and free in the bio fouling. This furthermore ensure the pump sump and pump suction side free through the slime business expansion. The free residual chlorine and the condenser outlet can be measured to look for the chlorine dosing as the chlorine demand of sea water varies according to the season additionally, the quality with the sea ingesting water.
Shock dosing chlorination - Dosing point No.3
Shock dosing of chlorination is done effectively at 1 - 5 ppm depending upon the quality of sea water. Require two or three dosing time is one cycle time for every 8 hours shift they're able to be sufficient to maintain condenser cooling surface devoid of bio fouling and conserve the efficiency among the condenser and power time.
Theory of Sea chlorination
In Sea water at pH numerous.4 - 8.1 less than 50% of chlorine is available as fast acting Hypochlorous acid. However Sea water also contains 60 mg/litre (ppm) bromide ion which displaces the chlorine, being stronger oxidizing agent to supply hypobromous acid.
Cl2 + H20 --------- HOCL + H+ + Cl-
HOCL + Br ---------- HOBr + Cl-
When chlorine is dissolved in water, it hydrolyzes rapidly in accordance with the above equation. The rapidity of the reaction can be expressed that the chlorine molecule reacting with hydroxyl ion rather when compared with the water module.
Cl2 + OH- ------- HOCL + Cl
CHLORINE DOSING POINTS
This reaction is of great practical important around the chemistry of aqueous chlorine solution discharging from chlorination equipment. Away from the chlorinator outlet the chlorine solution is limited by design to less than 3500 mg./litre of chlorine in water treatment. At a concentration probably the most highly buffered solution will result pH of only 3. On this pH the amount of molecular chlorine in equilibrium with HOCl is ample. Concentration higher than 3500 mg/l causes excessive chlorine gas release, in the point of application which isn't desired.
Considering sea water at pH 8 the reaction by addition of chlorine with sea water can lead to the presence of HOCl, OCl, HOBr and OBr and will act to create the hostile environment for living living bacteria. We will have 70% to 90% HOBr as extremely rapid toxicant.
The aim of chlorination is to achieve Hypochlorous acid (HOCL) and hypochlorite ion(OCl which is effective in preventing fouling of the cooling water circuits. Most of the objective in water treatment chlorination is create a hostile environment which will discourage marine organisms from establishing themselves and growing on the internal surfaces of PIPE WORK AND CONDENSER SURFACE. The hostile environmental is created and maintained by continuous chlorination.
Fouling control with chlorine dosage
The control of algae and slime their pipe work and condensers can performed by shock/intermittent chlorination. How much continuous chlorination and involving frequency and duration of intermittent shock chlorination is different from one area to someone else. It also depends upon 4 seasons of the year depending on biological activity and quality of water. The optimum treatment is achieved by operating experience.
Continuous chlorination dosing level is in your community of 2.3-2 ppm. Shock chlorination dosing level is practiced at 2-5 ppm for 1 cycle time any 4-8 a long. The practice with natural sea water chlorination is observe the total 30 minutes demand. Normal water is dosed with certain quantity of equivalent chlorine. The residual is measured after 30 minutes. The difference between the initial dose level and the rest of the level is reported as the chlorine sensible.
Only shock dosing chlorination is not sufficient for effectively treating the sea water. When shell forming organisms grow in the water, they attach themselves to the piping. Even when the organism is killed by Shock chlorination, the dead remains linked to the piping and subsequently can break free and clog the piping with disastrous results. Continuous chlorination prevents settlement and growth of marine organisms. Various tests conducted indicates residual of three.1 mg/litre will prevent the connected with marine microorganisms. To that end, Jiangsu Peide Water Treatment Equipment Co., Ltd. has successfully built a solid foundation and infrastructure for water treatment equipment manufacturers manufacturing. You can get a of any specification from Jiangsu Peide Water Treatment Equipment Co., Ltd. as we have varied specifications to suit different industrial water filtration equipment needs and cater to a wide client base existing in both domestic and overseas market. please feel free to enquire us at Peide Water Treatment Equipment. Peide focuses on three key elements—process, people, and technology—the authors found that people of two seemingly opposite cultures are able to work together in a project-based environment to complement each other and reap mutual benefits for a win-win result. water treatment parts water treatment equipment manufacturers with industrial water filtration equipment are used extensively in water treatment parts.