Chlorine diffusers

Ukshe, E.A. and Leonova, L.S. (1970). Chlorine diffusion in fused lithium chloride, Elektrokhimiya, 6, 1423-5. 

If more chlorine water be added the smell of chlorine will become noticeable, and this excess of chlorine diffusing into the air around will destroy the sulphuretted hydrogen odour which before filled the room. 

How much chlorine diffuses into the stratosphere from HCFCs ... 

Stuffing box Pfaudler high-duty type with bronze sleeve Chlorine diffuser 1-in. silica tube with twenty-five M in. tangential jets Gaskets Corning Type R-3... 

Diffusers are used to spread the chemical and to provide mixing energy. There are many different types of diffusers. Ozone and carbon dioxide feed systems commonly use fine bubble diffusers. Chlorine diffusers (Figures 2-5, 2-6, and 2-7) are often perforated pipe or even a simple open pipe. Many liquid chemicals are delivered into the process flow with diffusers. It is important to spread the chemical evenly in the water and to provide adequate mixing. 

The recreated chlorine diffuses back to the metal/salt melt interface and allows a subsequent formation of iron chloride. Chlorine is not consumed and thus this process is catalysed by chlorine. Figures 30.16-30.18 give the... 

R. L. Earrar, Jr., and E. J. Barber, Some Considerations in the Handling of Fluorine and the Chlorine Fluorides, report K/ET-252, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Term., 1979. 

A number of chemiluminescent reactions have been studied by producing key reactants through pulsed electric discharge, by microwave dissociation, or by observing the reactions of atoms and free radicals produced in the inner cone of a laminar flame as they diffuse into the flame s cool outer cone (182,183). These are either combination reactions or atom-transfer reactions involving transfer of chlorine (184) or oxygen atoms (181,185—187), the latter giving excited oxides. 

Disinfection. Ozone is a more effective broad-spectmm disinfectant than chlorine-based compounds (105). Ozone is very effective against bacteria because even concentrations as low as 0.01 ppm are toxic to bacteria. Whereas disinfection of bacteria by chlorine involves the diffusion of HOGl through the ceU membrane, disinfection by ozone occurs with the lysing (ie, mpture) of the ceU wall. The disinfection rate depends on the type of organism and is affected by ozone concentration, temperature (106), pH, turbidity, clumping of organisms, oxidizable substances, and the type of contactor employed (107). The presence of oxidizable substances in ordinary water can retard disinfection until the initial ozone demand is satisfied, at which point rapid disinfection is observed. 

The diffusion process has not been designed to ensure sterility, although temperatures above 65°C significantly retard microbial activity. Sulfur dioxide, thiocarbamates, glutaraldehyde, sodium bisulfite, and chlorine dioxide are all used, occasionally disregarding their redox incompatibilities, to knock down or control infections. The most common addition point is to the water from the pulp presses as it is returned to the diffuser. Surfactants ate almost... 

Carburization by Thermal Diffusion. Carburization of chemically processed metal or metal-compound powders is carried out through sohd-state, thermal diffusion processes, either in protective gas or vacuum. Carbide soHd solutions are prepared by the same methods. Most carbides are made by these processes, using loose or compacted mixtures of carbon and metal or metal-oxide powders. HaUdes of Group 5 (VB) metals recovered from ores by chlorination are similarly carburized. 

Porous carbon and graphite are used ia filtration of hydrogen fluoride streams, caustic solutions, and molten sodium cyanide ia diffusion of chlorine iato molten aluminum to produce aluminum chloride and ia aeration of waste sulfite Hquors from pulp and paper manufacture and sewage streams. 

Many related processes use charged membranes and/or EMF. Electrodialytic water dissociation (water splitting), diffusion dialysis, Donnan dialysis, and electrolysis are related processes. Electrowsis (chlorine-caustic) is a process of enormous importance much of which is processed through very special membranes. 

Chlorinated rubber is also used to promote the adhesion of solvent-borne CR adhesives to metals and plasticized PVC. Addition of a low molecular weight chlorinated rubber (containing about 65 wt% chlorine) improves the shear strength and creep resistance of polychloroprene adhesives [75] but a reduction in open time is also produced. A heat reactivation (process in which the surface of the adhesive film is raised to 90-100°C to destroy the crystallinity of the film and allowing diffusion to produce polymer chain interlocking more rapidly) restores tack to the polychloroprene adhesives. 

Hypochlorous acid and hypochlorite ion are known as free available chlorine. The chloramines are known as combined available chlorine and are slower than free chlorine in killing microorganisms. For identical conditions of contact time, temperature, and pH in the range of 6 to 8, it takes at least 25 times more combined available chlorine to produce the same germicidal efficiency. The difference in potency between chloramines and HOCl can be explained by the difference in their oxidation potentials, assuming the action of chloramine is of an electrochemical nature rather than one of diffusion, as seems to be the case for HOCl. 

Jamieson and McNeill [142] studied the degradation of poIy(vinyI acetate) and poly(vinyI chloride) and compared it with the degradation of PVC/PVAc blend. For the unmixed situation, hydrogen chloride evolution from PVC started at a lower temperature and a faster rate than acetic acid from PVAc. For the blend, acetic acid production began concurrently with dehydrochlorination. But the dehydrochlorination rate maximum occurred earlier than in the previous case indicating that both polymers were destabilized. This is a direct proof of the intermolecular nature of the destabilizing effect of acetate groups on chlorine atoms in PVC. The effects observed by Jamieson and McNeill were explained in terms of acid catalysis. Hydrochloric acid produced in the PVC phase diffused into the PVAc phase to catalyze the loss of acetic acid and vice-versa. 

It is worthwhile drawing attention to health hazards associated with film infected water systems which also cause corrosion. Two of the most common are Legionnaires disease and so called humidifier fever . Because of strong adhesion of biofilms and diffusion rates through the film treatment based on cleaners and chemical sterilisers such as chlorine often fail similar considerations apply to other systems in industry, e.g. food, paint, oil and gas are examples where biofilm activities have given massive problems. 

All of us are familiar with the process of gaseous diffusion, in which gas molecules move through space from a region of high concentration to one of low concentration. If your instructor momentarily opens a cylinder of chlorine gas at the lecture table, you will soon recognize the sharp odor of chlorine, particularly if you have a front-row seat in the classroom. On a more pleasant note, the odor associated with a freshly baked apple pie also reaches you via gaseous diffusion. 

---