Location - Spirax Sarco help dairy plant regulate air ... Plant Air... · Very hot air is also...
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The issue Dairy based powders, such as infant formula or protein/whey powders are manufactured using a very large conical-shaped spray dryer where concentrated product is atomised and evenly sprayed into the drying chamber. Very hot air is also dispersed into the dryer to heat and evaporate the final water residue. The main challenge during these processes is ensuring an accurate air temperature is met across all process load conditions. Typically, the air is heated using high pressure steam coils. The air heaters are generally designed in stages or separate coils where the blown air is pre-heated, and then four direct steam stages further lift the temperature to the desired set-point ready for delivery to the spray dryer. In the case of a recent air heater installation in a New Zealand dairy plant, we were asked to help with the design, sizing, selection and commissioning of the 32 bar g steam supply to the 5-staged air heater within the plant. The solution As with any steam supply to point of use, the pre-conditioning is important to ensure effective heat transfer and maximum longevity of equipment. Therefore, a large vertical baffle-type separator was designed and locally manufactured to remove all entrained moisture from the supply pipes. 100 mesh strainers also were included to help remove debris. The control valves that regulate steam into the coils are critical to this application, and they modulate accordingly to meet the air temperature set-point of 215°C. The Spirax Sarco control valve sizing suite enables valves to be selected based on a number of parameters, ensuring optimum control and minimum noise across all operating conditions including start-up. In this case, the Spiratrol KEA series were selected with tailored internals – one 3” and one 4” valve - complete with air-actuators and the SP500 smart positioner which provides accurate valve position feedback to the site Building Management System (BMS). Spirax Sarco help dairy plant regulate air temperature in powder milk production to ensure high product quality Dairy Plant CASE STUDY Objective: Ensure accurate air temperature is achieved in powder milk production Solution: Spirax Sarco designed, sized, selected and commissioned a 32 bar g steam supply to a 5 staged air heater Results: The air temperature is accurately controlled and the final product is of a consistent high quality. Company - Dairy Plant Location - New Zealand During commissioning, the valve position needed to be tweaked, so one of the 3” valve features was utilised. Our engineers were able to swap out the internals “in-situ” adjusting the valve kv to better reflect the actual operating parameters. Indications to date suggest a well-tailored control loop will deliver fast valve responses to load changes, and accuracy far better than the air temperature design requirement of ±5°C. Steam systems need to be brought on line gradually during the dryer and plant start-up process, and our design reflected this. On site automated “warm-up” valves were fitted to ensure that pipe and component thermal stress is kept to a minimum, and air and condensate is properly removed. The air heater steam float traps were also sized to cope with low pressure and high condensate loads to ensure condensate is continuously removed. (Some air heater designs utilise orifice plates on the steam outlet, which are problematic in a number of ways. Over time the orifice hole erodes from allowing more condensate and steam to pass. With no control, the energy losses become significant and the air heaters’ efficiency, controllability and throughput is impaired.) Downstream of the steam traps the high pressure condensate from each steam heater is piped into the first pre-heat “flash- steam” stage and sub-cooled to 90°C using a condensate temperature control valve, before delivery back to the boilerhouse. The flash steam system recovers previously lost energy and also minimises thermal stresses in the main air heater coils and fins to ensure longevity.
Transcript of Location - Spirax Sarco help dairy plant regulate air ... Plant Air... · Very hot air is also...
The issueDairy based powders, such as infant formula or protein/whey powders are manufactured using a very large conical-shaped spray dryer where concentrated product is atomised and evenly sprayed into the drying chamber. Very hot air is also dispersed into the dryer to heat and evaporate the final water residue.
The main challenge during these processes is ensuring an accurate air temperature is met across all process load conditions. Typically, the air is heated using high pressure steam coils. The air heaters are generally designed in stages or separate coils where the blown air is pre-heated, and then four direct steam stages further lift the temperature to the desired set-point ready for delivery to the spray dryer.
In the case of a recent air heater installation in a New Zealand dairy plant, we were asked to help with the design, sizing, selection and commissioning of the 32 bar g steam supply to the 5-staged air heater within the plant.
The solutionAs with any steam supply to point of use, the pre-conditioning is important to ensure effective heat transfer and maximum longevity of equipment. Therefore, a large vertical baffle-type separator was designed and locally manufactured to remove all entrained moisture from the supply pipes. 100 mesh strainers also were included to help remove debris.
The control valves that regulate steam into the coils are critical to this application, and they modulate accordingly to meet the air temperature set-point of 215°C. The Spirax Sarco control valve sizing suite enables valves to be selected based on a number of parameters, ensuring optimum control and minimum noise across all operating conditions including start-up. In this case, the Spiratrol KEA series were selected with tailored internals – one 3” and one 4” valve - complete with air-actuators and the SP500 smart positioner which provides accurate valve position feedback to the site Building Management System (BMS).
Spirax Sarco help dairy plant regulate air temperature in powder milk production to ensure high product quality
Dairy PlantCASE STUDY
Objective: Ensure accurate air temperature is achieved in powder milk production
Solution: Spirax Sarco designed, sized, selected and commissioned a 32 bar g steam supply to a 5 staged air heater
Results: The air temperature is accurately controlled and the final product is of a consistent high quality.
Company - Dairy Plant
Location - New Zealand
During commissioning, the valve position needed to be tweaked, so one of the 3” valve features was utilised. Our engineers were able to swap out the internals “in-situ” adjusting the valve kv to better reflect the actual operating parameters. Indications to date suggest a well-tailored control loop will deliver fast valve responses to load changes, and accuracy far better than the air temperature design requirement of ±5°C.
Steam systems need to be brought on line gradually during the dryer and plant start-up process, and our design reflected this. On site automated “warm-up” valves were fitted to ensure that pipe and component thermal stress is kept to a minimum, and air and condensate is properly removed. The air heater steam float traps were also sized to cope with low pressure and high condensate loads to ensure condensate is continuously removed.
(Some air heater designs utilise orifice plates on the steam outlet, which are problematic in a number of ways. Over time the orifice hole erodes from allowing more condensate and steam to pass. With no control, the energy losses become significant and the air heaters’ efficiency, controllability and throughput is impaired.)
Downstream of the steam traps the high pressure condensate from each steam heater is piped into the first pre-heat “flash-steam” stage and sub-cooled to 90°C using a condensate temperature control valve, before delivery back to the boilerhouse. The flash steam system recovers previously lost energy and also minimises thermal stresses in the main air heater coils and fins to ensure longevity.
Dairy Plant
The resultFor this dairy company, the installation of the new air heater temperature controls was a huge success. By working directly with our expert engineers who provided advice and implemented best practices in the steam system design, they can be assured that the air temperature is accurately controlled and the final product is of a consistent high quality.
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Inlet air
heater
Airdisperser
Concentrateheater
Concentrate
Positive feed pump
Oversize powder
Baghouse
Inlet fanr
Exhaust fan
Exhaust
Centrifugaldisk
atomiser
Fines return
Spray drier
Fluid bed
Blower
Dehumidifier
Filter
Collectiion cyclones
FilterSifter
Airheater Fluidised bed
inlet fan Packaging or bulk storage
Example of spray dryer system
For more information on this, or any of our products or services please get in touch:
0800 800 229
www.spiraxsarco.com/nz
