Chlorine injection

NOTE Where RW quality is poor, a booster unit is generally required on the front of the multifunctional tank, so that the concept of a single tank is lost. Additionally, where iron- and sulfate-reducing bacteria may be present, periodic sterilization of the bed using chlorine injection becomes necessary. 

During maintenance work, simultaneous release of chlorine and acetylene from two plants into a common vent line leading to a flare caused an explosion in the line [10], The violent interaction of liquid chlorine injected into ethane at 80°C/10 bar... 

None No flow - chlorine to chlorination loop No/low level in chlorine drum. Pressure reducing valve fails closed. No chlorine flow to tower basin. Low chlorine concentration in tower basin. Local pressure indication on chlorine injection line. Local flow indication on chlorine injection line (rotameter). 6 ... 

Any biological deterioration of cellulose acetate membranes is always by "accidental". To prevent this kind of deteriorations, chlorine injection to feed water is common practice. Inadequate control of chlorine injection may result in the enzymic deterioration of cellulose acetate membrane. 

During maintenance work, simultaneous release of chlorine and acetylene from two plants into a common vent line leading to a flare caused an explosion in the line [10]. The violent interaction of liquid chlorine injected into ethane at 80°C/10 bar becomes very violent if ethylene is also present [11]. The relationship between critical pressure and composition for self-ignition of chlorine—propane mixtures at 300°C was studied, and the tendency is minimal for 60 40 mixtures. Combustion is explosive under some conditions [12]. Precautions to prevent explosions during chlorination of solid paraffin hydrocarbons are detailed [13]. In the continuous chlorination of polyisobutene at below 100°C in absence of air, changes in conditions (increase in chlorine flow, decrease in polymer feed) leading to over-chlorination caused an exotherm to 130°C and ignition [14],... 

Important parameters to be considered in the design of chlorination unit operations facilities shonld include chlorine feeders, dosage control, chlorine injection and initial mixing, contact time and chlorine dosage, and maintenance of self-cleaning velocities throngh the chlorine contact tank. Each of these will be discussed in succession. 

Tabazadeh A. and Turco R. P. (1993) Stratospheric chlorine injection by volcanic eruptions HCl scavenging and implications for ozone. Science 260, 1082-1086. 

The control of these natural organics can be tackled in several ways by reducing the total amount of precursors in the feedwater, by relocating the position of chlorine injections, by changing the nature and the amount of oxidant added, or the temperature and pH value during certain unit operations, or by ultimate removal of any THM, formed prior to distribution. 

Where chlorination is made by chlorine injection in the liquid phase, gas phase explosion hazard is related to chlorine evolution in the vapour phase, giving a flammable mixture with the solvent or reaction mixture vapour. Here hazard assessment is achieved by comparing the gas phase composition with the flammable area of the gaseous mixtures. Auto-ignition is also considered because the autoignition temperature of gaseous mixtures containing chlorine is close to the ambient temperature. 

To keep the reactor gas phase above the U.F.L. in chlorine (method 2) may not be quite safe. On start-up the temperature must be set to the process normal value ensuring enough fuel vapour pressure before chlorine injection. If a condensor is used where the fuel vapour pressure is depleted, the gas flow composition may enter the flammable range. Glass condensors are better not used or protected from light. 

The rate of isomerization, r, was found to be controlled by the surface reaction of n-pentene on AI2O3, instead of the adsorption on n-pentene on these sites, as found by Hosten and Froment for a slightly different catalyst and with continuous chlorine injection (see Chapter 2)... 

Catalyst Rejuvenation. After all the coke is bum, it is necessary to redisperse, reduce and sulfide the metal, and adjust the acidity by chlorine injection. 

The detection limit of NCI-MS in the SIM is in the range 0.05-0.1 pg of each congener with more than four chlorines injected into the GC. Usually, NCI-MS provides a much higher sensitivity than EI-MS but the complexity of use and the high cost of purchase and maintenance restrict their use in routine analyses of PCBs. Tandem mass spectrometry (MS-MS) analysis by IT-MS systems has also become a competitive technique for the determination of PCDD/Fs and PCBs. 

Coastal power and process industry plants have used chlorine to control biofouling and shme formation for many years. Chlorine injection is normally provided for heat exchangers in coastal plants that are seldom cleaned more than once a year and for naval ships that must maintain their equipment at maximum efficiency at all times. Chlorine may be added in the gaseous form or developed in situ via electrolytic chlorine generation. 

Chlorine Resistance Chlorine resistance is significantly better with the CTA membrane chemistry than with membrane chemistry based on polyamide. This allows the biological control and stable operation of the RO module by the intermittent chlorine injection (ICI) disinfectant method. 

Test Conditions Test conditions and test requirements are shown in Table 2.5. The test was aimed at satisfying the following plant specification. For prevention of biological fouling, it was shown that the ICI method provided effective chlorine injection. 

Feed pressure 6.9 MPa max. Feed tempeialuie 16 37°C Feed TDS 45,000 mg/L Recovery 35% Chlorine injection ICI 1. Permeate quality Less than 500 mg/L as TDS 2. Permeate flow rate per module 10.77 m /day 3. Differential pressure Normal increase or no change... 

Nada, N., Iwahashi, H., and Umemori, F. (1994). Test result of the intermittent chlorine injection method in Jeddah 1 plant. Desalination 96, 283. 

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