Rubber lining conditions

Friction loss in rubber-lined pipe is usually considered equivalent to that in new steel pipe of one-half to one nominal size smaller, with little or no change due to aging, unless knowm conditions can be interpolated. For a given inside diameter, the friction loss is the same (or slightly less) than clean steel pipe. 

The decision to retrofit or install new filters is influenced by plant-specific factors such as the condition of the existing filters, compatibility of the filters to retrofit, availability of space within the plant, etc. Bayer s analysis of the costs and benefits of the retrofit compared to the investment in new filters did not show a clear favourite either decision could be justified. With regard to the rubber lining, gaskets, hydraulic system etc., the Kellys were in very good condition. Because of this, the decision was made to retrofit two of the filters and to use them in a separate brine circuit for the new electrolysers, with a second circuit feeding the amalgam plant. 

With reaction conditions of 200-225°F, 150—225 psi, and a palladium chloride-cupric chloride catalyst, MEK yields are 80-90%. The operating costs of the Wacker process for MEK (and acetone and several other petrochemicals as well) are relatively low. But the plant Is made of more expensive materials. Because of the corrosive nature of the catalyst solution, critical vessels, and the piping are titanium-based.(chats expensive ), and the reactor is rubber-lined, acid-resistant brick. ... 

Whilst carbon and stainless steels are commonly used materials of construction, increasing use is being made of non-metallic and rubber lined equipment. The selection of the material of construction should take into account the cases of the worst process conditions that may occur under foreseeable conditions and should be applied to all components including valves, pipe fittings, instruments and gauges. Both composition (e.g., chlorides, moisture) and temperature deviations can have a significant direct effect on the rate of corrosion. The operator should demonstrate that procedures are in place to ensure that potential deviations in process conditions such as fluid temperature, pressure and composition are identified and assessed in relation to the selection of materials of construction for piping systems. 

Though a standard norm or absolute reference value is not available for comparison in any of the international standard specifications and the technical and research publications with respect to the chemical resistance properties of rubber, liquid immersion tests certainly provide relative and useful data with which the suitability of anticorrosive rubber lining compounds can be assessed with a fair degree of accuracy. For this reason manufacturers and applicators of rubber lining resort to tests under simulated conditions instead of accelerated ageing immersion or swelling tests. 

When removing chlorine from the brine more hygienic working conditions are conduced and operations facilitated, as cast iron or steel pumps, vessels and manifolds not protected by rubber lining may be used. 

Severe corrosion conditions which exist throughout this process have led to the use of wood, lead-lined wood, polyester-fiberglass, and rubber-lined steel for construction of much of the equipment, with dense carbon or a nickel alloy being favored for heat exchangers. 

To transport 25 million tons of coal per year, only one meter diameter pipe is required. All the disadvantages of rail transportation are overcome including noise, dust, spillage and obstruction during traffic. Under favourable installation conditions, hydraulic transportation cost can be 50—60% less than the cost of rail transport. Slurry proportions for efficient transportation through rubber lined pipes are usually around 50% solids by weight. 

In the South African mining industry most processes for recovering precious metals, coal, minerals and diamonds are wet methods, involving the suspension of solids in water [1], In the control of such wet abrasive conditions in the pumping of fine particles size slurries, particle size separation in cyclones and in floatation cells, the choice of soft natural rubber lining is the most cost effective. 

The Indian Standard for lining of vessels and equipment for chemical processes, IS 4682-1 [22], mentions that the use of linings with rubber for protection against corrosion has been the normal industrial practice for more than half a century. The lined vessels and tanks are quite suitable for use either under vacuum condition or high pressure conditions. The appropriate thicknesses for rubber linings are recommended in this standard for various corrosive and abrasive conditions as follows ... 

Bubject to wear on pumps, agitators, etc. In dilute solutions, wood is aatisfactory where conditions allow it to swell and seal pores, cracks, etc. Care must be taken that hoops, tie rods, etc., are coated with an inert material such as tar, pitch, silicates, epoxy and polyester resins, polyvinyl chloride, etc. For hydrochloric acid, rubber-lined steel is excellent at low... 

Heat exchangers in brine service are usually titanium or copper-nickel alloys, and pumps are made of Type 316 SS, Ni-Resist titanium, rubber-lined steel, or FRP. Storage tanks use many of the same materials employed in piping systems, the choice reflecting processing conditions and the importance of avoiding contamination. 

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