GEA Niro evaporators concentrate heat-sensitive products using design concepts that make it possible to operate with low temperature differentials. The ability to utilize long tubes and hence extensive heating surfaces ensures optimum liquid distribution, tube loadings, thermal efficiency, long production runs, and shortest CIP times. All Niro evaporators are fully welded construction to meet all sanitary standards.
In multiple-effect evaporators with TVR, the heating medium in the first calandria is the product vapor from one of the associated effects, compressed to a higher temperature level by means of a steam ejector (TVR). The heating medium in any subsequent effect is the vapor generated in the previous calandria. Vapor from the final effect is condensed with incoming product, supplemented by cooling water if necessary. The condensate can be used a boiler feedwater, CIP liquid, or for preheating the drying air of an associated spray dryer.
In evaporators with MVR, the heating medium in the first effect is vapor developed in the same effect, compressed to a higher temperature by means of a high-pressure fan (MVR). Any excess vapor from the high heat section is condensed or may be utilized in a high concentrator. The condensate temperature is, however, too low for further beneficial waste heat utilization.
Since prices for steam and electricity vary by region, the choice between MVR and TVR (and in the case of TVR, the number of stages) depends on local prices, possible utilization of hot condensate, and depreciation of the capital cost. Both systems produce the same product quality as long as certain critical design parameter requirements are met.