Balance tank

The equipment needed includes a balance tank, regenerative heating unit, positive pump, plates for heating to pasteurization temperature, tube or plates for hoi ding the product for the specified time, a flow-diversion valve (FDV), and a cooling unit (Fig. 4). Often the homogenizer and booster pump also are incorporated into the HTST circuit. 

On the outlet of the holder tube, the FDV directs the pasteurized product to the regenerator and then to the final cooling section (forward flow). Alternatively, if the product is below the temperature of pasteurization, it is diverted back to the balance tank (diverted flow). The FDV is controlled by the safety thermal-limit recorder. 

Alternatively, the contaminated surface drainage must be segregated from the normal storm water drains and may, for example, be led into a balancing tank. This tank must be large enough to even out the variations and to allow the contents to be added to the works effluent (treated or untreated) over a period of time. Provision must be made for periodically removing the inevitable accumulation of silt in the bottom of the tank. 

The raw juice is normally passed through a balance tank (or feed tank) before being fed to the pasteuriser. 

In the basic system described above, if the temperature drops below the pasteurisation temperature or the flowrate exceeds that for the correct holding time there is no other choice than to shut down the process and to clean and resterilise the equipment before production can be restarted. The consequences of this may be limited by diverting the flow of insufficiently pasteurised product back to the balance tank forward flow may be resumed once correct conditions are restored. The divert valve should be placed sufficiently downstream of the temperature monitoring probe that the system response time (probe, controller and valve) is less than the time taken for the unpasteurised product to reach the valve. 

Pasteurised product is either sent to a proportioner and diluted to the desired strength (if produced as a syrup) and then carbonated and mixed with carbon dioxide or sent direcly to a filling machine excess product is diverted (cold diveit) back to the balance tank of the pasteuriser. The system is typically sized for a flow of 5-10% in excess of that required the positive forward flow maintains the sterility of the system so that bacteria, etc. cannot pass up the cold diveit line against the flow. 

The aseptic processor either feeds the filler directly, with excess flow returning to the balance tank (and positive flow maintained under all circumstances), or feeds directly to an aseptic storage tank, which acts as a buffer between the processing and filling operations. 

Other sources of water for reuse may be from large industrial balance tanks and lakes, process save-all tanks, oxidation ponds, and receiving pits for boiler blowdown, or ion-exchange regeneration effluents. 

Fig. 65. Production diagram of polymethylsilsesquioxane varnish by the continuous technique 1, 2, 4, 5,8, 10 - batch boxes 3 - agitator 6 - hydrolyser 7, 12 -Florentine flasks 9 - heat exchanger 11 - neutraliser 13 - flusher-receptacle 14, 16, 18 - collectors, 15 - vacuum distillation tank 17 - cooler 19 - balancing tank 20 - druck filter...

The toluene solution of the product of hydrolytic condensation with pH of the nonaqueous solution not lower than 5 and the nonvolatile content of 40 3% is sent for completion into collector 14 the toluene solution of the product of hydrolytic condensation with pH of the nonaqueous solution lower than 5 and the nonvolatile content of less than 37% is sent into tank 15 for additional flushing and partial distillation of the solvent. The additional flushing in the tank is carried out with the solution of sodium chloride (like the second flushing) then the contents of the tank are heated to 40-60 °C and held for 2-10 hours. The bottom layer, the settling products, is poured off and collected in collector 16. Then a vacuum is created in the tank (the residual pressure is 0.05-0.07 MPa) and the solvent is partially distilled (until the nonvolatile content is 40+3%). The distilled solvent vapours are condensed in cooler 17 and collected in collector 18. If the moisture content is above 1.5%, the solvent is sent into collector 16 for subsequent additional drying. The toluene solution of polymethylsilsesquioxane is poured from receptacle 14 or tank 15 into balancing tank 19, where several batches of varnish are mixed and balanced. The finished varnish is analysed to determine the nonvolatile content, pH of the nonaqueous solution, viscosity and gelatinisation time. 

If pH is lower than 5, the varnish is treated with kil or active coal. Balancing tank 19 is loaded with kil or coal (5-12% of the varnish amount) the mixture is agitated for 1-2 hours. If pH is 5+7, the varnish is sent by nitrogen flow (0.3 MPa) at agitation through druck filter 20 into containers. 

Figure 11 Description of dual microcoil probe. (A) Two coils wrapped around a polyimide sleeve (B) Dual-coil probe mounted on top of the probe head. (C) Schematic of balanced tank circuit used for each microcoil. Coil (L), series capacitors (Cs) 3.3 pF, tuning capacitors (CT) 0.6-4.5 pF, matching capacitor (CM) 0.6-4.5 pF, bridge capacitors (CB) 24 pF. (Reproduced with permission from Ref. 41. Copyright 2002 American Chemical Society.)...

The prepared emulsion is fed via a balance tank to a high-pressure pump, usually of a piston variety to a series of in-hne SSHEs. Once in the pasteurizer heating cylinders, the product is pasteurized and held prior to being subjected to precoohng and prepared for crystallization. Cooling, stabilizing, and texturizing of the emulsion are continuously undertaken within a series of A and B units. 

Excess product from the packaging operation is continuously remelted in a rework SSHE in a controlled manner and returned to the system via the balance tank or a positive pump facility for adding reclaimed material. 

Balance tank Graduated feed 6) 1st effect separator 8) 2nd effect evaporator 11) Condenser... 

Nutrient correction and pH balancing may be part of pretreatment steps before anaerobic treatment. Nutrient correction may involve dosing with a solution of mainly nitrogen and phosphorus, micro-nutrients or compounds to provide alkalinity. Alkaline compounds (e.g. lime, caustic soda) could also be used for pH correction, dosed in the balancing tank and/or directly inside the reactor whenever the need arises. 

The delivery from a reciprocating pump is pulsating and this can be a disadvantage in some applications. The fitting of a receiver or balancing tank in the delivery line can markedly reduce this pulsation. 

The sulfur froth in the slurry tank is pumped to a decanter centrifuge which concentrates the froth to a sulfur cake of about 30-40 wt% sulfur. The recovered scrubbing liquid is sent to the balance tank with the main stream of regenerated solution. 

Condensate is used to wash the sulfur cake and dilute the residual scrubbing liquor. The washed cake is fed into a separator/autoclave and steam is injected to melt the sulfur. The liquefied sulfur is held at a temperature of 13S°C and continuously separated from the residual scrubbing liquor in the separator/autoclave. The recovered aqueous phase is recycled back to the balance tank, and the reclaimed sulfur (purity > 99.7%) is the final product. 

A method of maintaining a constant-pressure fuel gas of uniform calorific value is indicated in Fig. l4-5. Liquid propane or butane may be fed into the system (sometimes actuated by an automatic calorimeter) to maintain the heating value, and natural gas is a< tted to carry the main heating load if process gases are insufficient. When sufficient process gas is produced to maintain well over 30 lb pressure in the balance tank, all... 

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