questions and answers about industrial kiln & dryer group
It's a personal interview where they really try to get to know you, your work ethic, and your standing on wanting to engage with the company. Nothing super formal, but it is an interview process from usually 8am-3pm and can be a bit intimidating. Use it to see if you would be a fit with the culture as well.
Dreaded it. Find something else. This job lies to you point blank. They put my family in a real bind due to flat out lies. And the southern plains is hands down the worst!!! Promise you run. Don't work here unless u have absolutely no other options.
types of compressed air dryers part 2: refrigerant and regenerative desiccant | compressed air best practices
The Compressed Air and Gas Institute is the united voice of the compressed air industry, serving as the unbiased authority on technical, educational, promotional, and other matters that affect the industry. Mention utilities and energy in a discussion about manufacturing and the Big Three - water, electricity and natural gas - immediately come to mind. But compressed air is commonly accepted as a manufacturing facility's fourth utility. A careful examination of a facility's compressed air system will likely reveal several opportunities to improve the performance of the compressed air system by effectively and efficiently removing moisture from the compressed air system. The Compressed Air and Gas Institute (CAGI) committed to issuing a series of articles discussing moisture in the compressed air system. The first article covered Why Do Compressed Air Systems Need Drying? This article will provide a brief overview of the two most popular compressed air drying technologies available Refrigerant Type and Regenerative Desiccant Type.
Because of such a wide breadth of product offering, we will cover each of these dryer types in some detail. It is always recommended that the compressed air treatment products be discussed in concert with the entire compressed air system and the application of the products. You should consult a compressed air expert to assure that the compressed air dryer selected is correct for your application.
Although it does not offer as low a dew point as can be obtained with other types, the refrigerant type dryer has been the most popular, as the dew point obtained is acceptable in many general industrial plant air applications. The principle of operation is similar to a domestic refrigerator or home air conditioning system. The compressed air is cooled in an air-to-refrigerant heat exchanger to about 35F, at which point the condensed moisture is separated and drained off. The air is then reheated in an air-to-air heat exchanger by means of the incoming air, which also is pre-cooled before entering the air-to-refrigerant heat exchanger. This means that the compressed air leaving the dryer has a pressure dew point of 35 to 40F. A lower dew point is not feasible in this type of dryer as the condensate would freeze at 32F or lower.
In a non-cycling refrigerant dryer (see below), the refrigerant circulates continuously through the system. This design provides rapid response to changes in operating loads. Since the flow of compressed air will vary and ambient temperatures also vary, a hot gas bypass valve or unloader valve often is used to regulate the flow of the refrigerant and maintain stable operating conditions within the refrigerant system. In most designs, the refrigerant evaporates within the air-to-refrigerant heat exchanger (evaporator) and is condensed after compression by an air-or water-to-refrigerant heat exchanger (condenser).
While older refrigerant type air dryers have used CFC refrigerants such as R12 and R22, newer designs are in compliance with the Montreal Protocol and use chlorine free refrigerants such as R134A and R407C or other environmentally friendly refrigerant blends. The properties of these newer refrigerants require careful attention to the refrigeration system design, due to differences in operating pressures and temperatures. Refrigerant type dryers should only be serviced by a licensed and trained technician to assure that the refrigerant material is properly handled.
Cycling type refrigerant dryers use refrigerant to chill a mass surrounding the air passage in the heat exchanger. This mass may be a liquid such as glycol or a metal such as aluminum block, beads or related substance, which act as a heat sink. The compressed air is cooled by the heat sink which has its temperature controlled by a thermostat and shuts off the refrigerant compressor during reduced loads, providing savings in operating costs but at higher initial capital cost.
These dryers use a desiccant, which adsorbs the water vapor in the air stream. A distinction needs to be made between adsorb and absorb. Adsorb means that the moisture adheres to the desiccant, collecting in the thousands of small pores within each desiccant bead. The composition of the desiccant is not changed, and the moisture can be driven off in a regeneration process by applying dry purge air, by the application of heat, or a combination of both. Absorb means the material that attracts the moisture is dissolved in and used up by the moisture. Absorption takes place in a deliquescent desiccant type dryer.
Regenerative desiccant dryers normally are of twin tower construction. One tower dries the air from the compressor while the desiccant in the other tower is being regenerated after the pressure in the tower has been reduced to atmospheric pressure. Regeneration can be accomplished using a time cycle or on demand by measuring the temperature or humidity in the desiccant towers or by measuring the dew point of the air leaving the on-line tower.
In the heatless regenerative desiccant type, no internal or external heaters are used. Purge air requirement can range up to 18% of the total air-flow. The typical regenerative desiccant dryer at 100 psig has a pressure dew point rating of -40F but dew points down to -100F can be obtained.
Heat reactivated regenerative desiccant dryers may have internal or external heat applied by heaters. In the internal type, steam or electricity may be used in heaters embedded in the desiccant bed. This reduces the amount of purge air required for regeneration to less than 10%. The purge air plus normal radiation is used to cool the desiccant bed after regeneration to prevent elevated air temperatures going downstream.
In externally heated regenerative desiccant dryers, the purge air is heated to an elevated temperature and then passes through the desiccant bed. The amount of purge air is approximately 5-10% of the air flow through the dryer. The purge air from the compressed air system can be eliminated if a blower is used for the circulation of heated atmospheric air through the desiccant bed. To protect the desiccant bed from oil contamination from the air compressor, a coalescing filter is required upstream of the dryer. To protect downstream equipment from desiccant dust or fines, a particulate filter downstream of the dryer also is also recommended.
With a focus on Demand-Side Optimization, compressed air dryers, filters, condensate management, tanks, piping and pneumatic technologies are profiled. How to ensure system reliability, while reducing pressure drop and demand, is explored through System Assessment case studies.
The CAGI website is an excellent source for more information on the application of compressed air dryers, compressed air dryer and filtration selection, and information on the Air Dryer & Filtration Section.
For more detailed information about CAGI, its members, compressed air applications or answers to any of your compressed air questions, please contact the Compressed Air and Gas Institute. CAGI educational resources include e-learning coursework on the SmartSite, selection guides, videos and as well as mentioned Compressed Air & Gas Handbook.
food processing equipment - shandong loyal industrial co.,ltd
Shandong Loyal Industrial Co.,Ltd. is a manufacturer of snacks extruder machine , hot air drying Machine , industrial microwave system , and a standing director of China Food and Drying Equipment Industry Association.The self-developed twin-screw extruder and single-screw equipment of Shandong Loyal Machinery have been used in production: puffed snack food, breakfast cereal corn flakes, fried pasta, bread crumbs, fruit chips, baby food, textured soy protein (TSP) food, fish feed and pet food. A variety of snack production line supporting products.At the same time, the batching, drying, flaking, baking, frying and spraying equipment matching the twin-screw extrusion system have all achieved independent design and production.Our extrusion system is widely used in: puffed snack foods, breakfast cereals, vegetable protein meat products, soy based nutrition bars, reconstituted rice, grain nutrition powder, modified starch, starch-based sticky music children's educational toys, degradable starch-based packaging Filling materials, bread crumbs and other food additives, pet food, aquatic feed, biology and chemical industries.