Introduction
The aim of this design project is to prepare a feasible report for the storage of 450tons of apple for a period about 4 month.
It is desired to design a controlled atmosphere cold storage facility and calculate the optimum total, fixed and variable costs in Eregli, Konya. The highest temperature in Eregli, Konya is 36 Celsius and the calculation for heat loss will be according to this temperature. There is a lot of apple variety in Turkey but the most consumed is Golden Delicious, so the storage temperature, CO2 % and O2 % will be the data’s of Golden Delicious.
Previous Work
Red Delicious: This one’s a classic – America’s favourite snacking apple. The heart-shaped fruit is bright red and sometimes striped. Crunchy with a mildly sweet flavour, Reds are also great in salads. Golden Delicious: It’s the all-purpose apple. Mellow and sweet, Goldens are great for eating out of hand, baking and salads. In salads and other dishes, their flesh stays white longer than other apples.
Gala: Pinkish-orange stripes over a yellow background are the signature of this crisp, aromatically-sweet, snappy apple
Fuji: This immensely flavourful, new variety was introduced to the U. S. from Japan in the 1980s, but now the U. S. produces more Fujis than Japan. Fujis are harvested in October and can be purchased October to August.
Granny Smith: Green, extremely tart, crisp, juicy and versatile, they’re available year-round. They are also excellent for snacking and salads. Warm days and cool summer nights ensure crunch and flavor for October harvest.
Braeburn: This apple’s rich, sweet-tart, spicy flavor is high-impact. Color varies from orange to red over a yellow background. Aromatic, juicy and crisp, this apple is very firm. Braeburns are great for snacking and baking
Honeyrisp : A sweet yet slightly tart flavor, this variety of apple is great for salads, baking, cooking or eating as a snack. The Honeycrisp Apple was created to grow well in cooler northern climates. It is a variety that stores well
Cripps Pink: Firm, crisp flesh and a unique, tangy-tart, sweet flavour are characteristic of this apple. Snackers and bakers give the variety high marks in consumer tastings.
Supplies of Cripps Pink last from November to August.
Cameo: Cameos are harvested in September and October. Available October to August Eregli Eregli is a town and a province of Konya in Turkey located in central Anatolia. It is 1054 apart-form the sea height and so in winter it can be consider as a cold city. According to Kromsan the yearly average temperature is 11. 1Celsius and the average of the lowest temperature is -22. 4Celsius and the highest temperature is around 36Celsius. Controlled Atmosphere (C. A) Every vegetable product undergoes metabolism. That is, every fruit is alive and breathes, consuming oxygen, not only while growing, but also after harvest.
The respiration process can be described as the breakdown by oxidation of carbohydrates such as starch, sugars and acids, which are present in the vegetable tissues. The products of respiration are: heat, carbon dioxide, water vapour and some aromatic compounds. The higher the respiration rate of a fruit, the more rapid will be its senescence and deterioration and subsequent reduced storage life. For a long time, refrigeration was the only method used for the storage of fresh fruit and vegetables. An airtight room is essential for proper controlled atmosphere storage of fruits and vegetables. Controlled atmosphere is the most technologically advanced process that is used to precisely control the atmospheric composition within the container throughout a shipment’s. C. A. together with temperature reduction, has a greater effect on the vegetables metabolism by reducing, for example, ethylene production of the fruit, by stopping the loss of chlorophyll (green colour)and by delaying pectin hydrolysis (maintaining flesh firmness), thus slowing the breakdown of vitamins and acids. From a point of view, this means not only preserving the organoleptic qualities of the produce, but also reducing losses due to pathogens (fungi) and to well-known physiological disorders such as common and senescent scald and the appearance of chilling injuries. Controlled atmosphere can increase the post-harvest life of some perishables by two to three times longer than other methods. The most two important steps in controlled atmosphere can listed as
Oxygen gas control:
To DECREASE:
- purging with nitrogen
- from liquid nitrogen through an evaporator
- from a membrane system nitrogen generator
- from a molecular sieve system nitrogen generator
Carbon dioxide control:
To INCREASE:
- dry ice
- pressurized gas cylinder
To DECREASE:
- molecular sieve scrubber
- activated charcoal scrubber
- sodium hydroxide scrubber
- Hydrated lime (use 0. 6 kg of hydrated lime to treat the air used to ventilate 100 kg of fruit. Air can be directed to pass through a box, located inside or outside the C. A. storeroom).
To regulate CO2 levels in a CA room, one of the simplest methods is the hydrated lime (Calcium carbonate) Ca (OH) 2 “scrubber”.
The scrubber is constructed using an insulated and airtight plywood box located outside the CA room. The box should contain enough lime for the entire storage period, but new lime can be added if CO2 absorption drops. The CO2 and hydrated lime reacts in a 1:1 ratio to form limestone and water. Lime with a smaller particle size (fine mesh) is more efficient at reacting with CO2 than lime with a coarse mesh. The following will maximize the effectiveness of your small-scale scrubber:
- Lime should be packaged in 25 kg bags that have no polyethylene liner.
- Each bag should be only partially filled (50%) to avoid the outer layer hardening and reducing efficiency over time. Lime bags should be stacked on a pallet equipped with shelves that allow a 10 cm space between layers to maximize air circulation.
- 50% of the recommended lime for the anticipated storage period can be placed on pallets on the floor of the storage room (this will consume the initially high CO2 produced by the fruit).
Controlled Atmosphere Storage for Apple Apples take in oxygen and give off carbon dioxide as starches in the flesh change to sugar. In the sealed rooms, this respiratory process reduced the oxygen, thus slowing the ripening process. The large, airtight CA rooms vary in size from 10,000 boxes to 100,000 boxes, depending on the volume of apples produced by the apple shipper and his marketing strategies. Timing of harvest is critical to good storage results.
Apples picked too early will not store well in CA nor will those that are past the proper maturity. In mid-August, apple growers start testing the maturity of their apples to accurately predict when to harvest their crop to put in CA rooms so the apples are mature, but not too ripe. Firmness, skin colour, seed colour, sugar level and flesh chlorophyll are tested. When the proper growing and harvesting techniques are used, many varieties of apples can store for 12 months or longer in CA. Most of these apples are shipped to market between January and September. Regular refrigerated storage is used for much of the fruit marketed in the fall and early winter months
To keep CO2 below 2%, about 12 kg of lime per metric tons of apples is recommended for 3 to 4 months of storage A summary of controlled atmosphere (CA) requirements and recommendations for apples Average optimum levels of popular apple varieties. The optimum temperature is 4Celsius and it can take a range between 3 – 7Celsius for average varieties of Apple Storage.
Discussions
The aim of this design report is to find all costs as the optimum total, fixed and variable co of a controlled atmosphere cold storage facility located on Eregli, Konya. This storage facility will store 450 tons of apples for 4 month. And lastly the cost of apple per kg that will be sold from this industry should be calculated. With all these calculations an offer should be made which will include the feasibility of this project. Firstly the assumptions below were made before the calculations and optimization.
- No money paid for the land, it belongs to the owner itself.
- The maximum temperature in Eregli, Konya is recorded to be 36 ? C
- Temperature inside the storage facility is -0. 5 ? C
- Heat loss is only through walls and roof
- No air leakage through the doors and windows No spoilage and defect on apple during these storage period, so after 120 days there will be no change in mass of apples.
- Price of apple/kg and electricity won’t change for 10 years.
- Transportation is done by seller, so no transportation cost.
Possible sources of errors:
- Temperature may vary
- During charging and discharging more refrigeration may be required
- Some accidents may occur, so final mass of sellable apple will change
Firstly optimization for dimensions of storage facility was done. The main idea was to define the smallest perimeter for rectangular shape building with height of 10 m.
According to this data, width was found to be 20,4 m and length of 16,02. The next step was to define optimum thickness of insulation.
Mineral wool panel was accepted to be most appropriate, while its thickness is defined to be at specific values: 60, 80, 100, 120, 150, 300 mm. For this optimization roof and side walls were assumed to have same thickness, concrete floor thickness of 30 cm. Heat transfer through windows and doors was not included, since they have ignorable surface area. Ground temperature was assumed to be constant during whole storage time and equal to 15 ? C. Using this data heat loss for 1 hour was calculated for each thickness. In order to transfer heat loss to money loss cost of electricity for refrigerator with C. O. P=5 for 120 days for 10 years was found. This cost was later added to cost of insulation, and the smallest one was accepted to be appropriated one.
Since heat loss was found, it was used to define power of refrigerating unit (6 kW), power for other equipment was directly defined by the suppliers according to capacity of storage facility. In order to find price of apple after storage an economical study was done. Total fixed investment was calculated using prices of the equipment with included transportation expenses.
Operating cost for 120 day was defined to be cost for electrical power used by equipment. Variable cost is summation of operating cost with total salary. Depreciation was evaluated using straight line method for 10 years, maintenance was assumed to be 10% of fixed investment excluding cost of construction. Last step was to bring all expenses and profit to present time, using 10% index and according to cost of apple their summation is equal to 0. Cost of apple after 120 day of storage was found to be 1,10 TL/kg while its purchase price is 0,80 TL/kg.
Recommended Design
Work on season basis for 120 days. Operating cost for 1 season: For 120 days Nitrogen generator (6 kW), CO2 Scrubber (3,8 kW), Industrial Fan (8*1,1 kW), Industrial Type Refrigeration System (6 kW) will be continuously working for 24 hours per day. Total 24,6 kW per hour power consumption.
Electric power cost for industry is 0,18556 TL/kWh. So total cost for 120 days will be 13146,55 TL/120 day. Lighting system won’t be used much during 120 days, so it is assumed that on the lighting it will be spent 50 TL/120 days. Forklift (28,8 kW) will be used only during loading and discharging facility. It is assumed that charging and discharging of apples are equal in time and last for 14 days each. So forklift will be used for 28 days and for 10 hours per day. Electric cost for forklift is found to be 1496,3 TL Assuming that other variable costs are small Total Variable Cost (VC) for one season will be 40492,85 TL.
Maintenance Cost is evaluated as Total Fixed Cost – Construction Cost)*0. 1 = 409055*0. 1= 40905. Depreciation done for 10 years using Straight Line Method is equal to 55360,19 TL per year. According to Union of Turkish Chambers of Agriculture price of 1 kg of Golden Delicious apple is 0,80 TL for 2009. We assume this price does not change during 10 year period. For interest rate 10% cost of apple was founded as follows: 450000(C-0,8)*6,144567-40905*6,144567+40492,85/1,1^10-553601,9-40492,85=0 Where 6,144567 is coefficient for compounding any cost for 10 years. According to this calculation C=1,10 TL/kg which is price of 1 kg apple after 120 day storage.
Conclusions and Recommendations
Aim of this design was to optimize a controlled atmosphere storage facility for Eregli Konya and to define price of apple after 120 days of storage. After all the calculations and evaluations in the area of chemical engineering economics, civil engineering, heat transfer and plant design described above it was found that, for the described system total fixed investment is equal to 553601,9 TL, variable cost is 40492,85 TL, and return on investment will be 10 years for the selling price of apple=1,10 TL/kg.
References
- Geankoplis, C. J. (2003). Transport Processes and Separation Process Principles. Fourth Edition. USA: Pearson Education, Inc.
- Peters, M. S. , Timmerhaus, K. D. , West R. E. , ( 2004). Plant Design and Economics for Chemical Engineers. Fifth Edition. Singapore: Mc Graw Hill.
- Chemical Engineering Plant Cost Index. Retrieved on 10. 11. 2009 from http://www. scribd. com/doc/18247545/Plant-Cost-Index-2009 • Retrieved on 17. 11. 2009 from http://www. storagecontrol. com/usedequipment. shtml
- Retrieved on 17. 11. 2009 from http://www. storagecontrol. com/documents/seriesII_scrub_ scs%20broch. pdf
- Retrieved on 17. 11. 2009 from http://www. alibaba. com/trade/search? SearchText =carbon+dioxide+scrubber&Country=&CatId=0&IndexArea=product_en&ssk=y&sq=y
- Retrieved on 17. 11. 2009 from http://www. alibaba. com/product-free/10254734/Industrial_Type_Refrigeration_System. html
- Retrieved on 17. 11. 009 from http://www. consteel. ru/index. html? page=19
- Retrieved on 17. 11. 2009 from http://www. volkanonline. com/catinfo. asp? cid=5161
- Retrieved on 17. 11. 2009 from http://www. pvc-pencere. co. cc/pvc_pencere_fiyatlari. html
