Equipment dosing

Even, limited PSAs use and contain much information. This information may come as memos and process reports and flow sheets, equipment layout, system descriptions, toxic inventory, hazardous chemical reactions, test, maintenance and operating descriptions. From this, data and analyses are prepared regarding release quantities, doses, equipment reliability, probability of exposure, and the risk to workers, public, and environment. An executive summary analysis is detailed, and recommendations made for risk reduction. Thus the information will be text, calculations of envelope fracture stresses, temperatures, fire propagation, air dispersion, doses, and failure probabilities - primarily in tabular form. 

No need for special dosing equipment Both automatic and manual control Efficient dispersion effect Flexibility in run length Easy to maintain and robust machine Wide application field... 

Noncorrosive materials should be used for the dosing equipment. The addition of iron salts also reduces the alkalinity of the wastewater, i.e., it may decrease the pH value. An effect of a low alkalinity of wastewater is a potential reduction of the nitrification rate in the subsequent treatment process. 

For continuous processes the catalytic reactor, or a hybrid process if satisfactory chemical dosing equipment is already installed, appear to be a near-optimum solution still for many installations. At moderate hypochlorite concentrations, economic benefit does accrue from using the catalyst in-loop rather than end-of-pipe, but these benefits may be offset by any required investment in heat-exchange capability. At concentrations above 10 wt% the integration of decomposition into the scrubbing process is beneficial to the overall cost base of hypochlorite treatment. 

In reality, often the only practical benefit of using timer-controlled biocide dosing equipment is the increased assurance it provides, in that the biocide(s) will actually be dosed to the cooling system at the planned time and for the planned duration. If this is of vital concern to the operator or mandated by regulations, then so be it. 

There is a growing trend for many operators not to have any direct involvement with their cooling system chemical dosing equipment (with regard to the addition of chemical, mixing and chemical dilutions, pump adjustments, and possibly even periodic equipment inspections and maintenance). The equipment may also not be owned by the customer. Rather, the water treatment service companies may lease the equipment to the customer, or provide free-on-loan equipment, together with all chemical dosing and control functions, as part of their services to the facility. 

Yarn lubricant for Two-for-one twisting with dosing equipment in the balloon-limiter. 

Plant items, pumps, lime and acid-dosing equipment, sand... 

The use of reducing chemicals, e.g. sulphur dioxide, sodium sulphite and sodium thiosulphate. The technique is likely to involve elaborate dosing equipment, e.g. automatic control, in order to maximise effectiveness at minimum cost. 

It is sometimes necessary to retrofit dosing equipment. It goes without saying that any such addition must be properly designed, engineered and installed so as to minimise the risk of malfunction and accident. 

The principal advantage of basing the mitigation of fouling entirely on chemical treatment is the relatively low investment cost of the dosing equipment. On the other hand there is potentially, a high annual operating cost. 

The most common cause of deposits in polymer/product preparation, filtration and dosing equipment is bacteria. Waterborne bacteria can thrive in make-up systems, causing slimy or pseudoplastic deposits to form. Once this has been identified, the systems need to be thoroughly cleaned, pipe work replaced and a treatment with biocide implemented. Care needs to be taken with the choice of biocide, it must be fuUy water soluble and compatible with the polymer/product otherwise reduced performance will result. 

Feeding (dosing) equipment is costly and requires extensive maintenance... 

Dosing equipment for additives or other chemicals which should be at same feed position or at separate additional ports. 

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