Trona mineralinden ticari ölçek soda üretim proseslerinin bilgisayar destekli tasarımı ve maliyetlendirilmesi

Durmaz, Nilüfer
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Fen Bilimleri Enstitüsü
Kimya sanayinin önemli hammaddelerinden olan soda sentetik alarak ve doğal kaynaklardan üretilmektedir. Soda üretiminde en önemli doğal kaynak trona mineralidir. Trona mineralinden soda üretimi sentetik yöntemlerle üretimden çok daha ekonomik olduğundan, tronadan soda üretim yöntemlerinin önemi gün geçtikçe artmaktadır. Dünyanın en büyük trona rezervine sahip olan A.B.D1 den sonra, ülkemizde Ankara'nın Beypazarı ilçesinde dünyanın ikinci büyük trona rezervi mevcuttur. Türkiye 210 milyon tonluk bu rezervi gerektiği şekilde değerlendirebildiği taktirde, sodanın girdi olarak kullanıldığı pek çok kimya sektörü gelişeceği gibi soda dış piyasasın dada önemli değişiklikler olacak, ülkemiz dış pazarlara açılma olanağına kavuşabilecektir. Trona mineralinden ticari ölçekte soda üretimi için iki yöntem kullanılmaktadır. Bunlar Monohidrat ve Sesquikarbonat Prosesleridir. İki yöntem temelde aynı olup başlangıç kademeleri farklıdır. Birinci yöntemde trona öncelikle kalsine edilir ve elde edilen ham soda saf laştırılır, ikinci yöntemde ise trona saf laştırılıp elde edilen Bodyum sesquikarbonat kristalleri sodaya dönüştürülür. Bu çalışmada Beypazarı trona mineralinden soda üretiminde kullanılabilecek olan Monohidrat ve Sesquikar bonat Proseslerinin ayrı ayrı tasarımın yapan ve yöntemlerini. ekonomik olarak karşılaştıran bir model geliştirilmiştir. Bu model ile Türkiye'de tronadan soda üreten bir tesisin kurulması durumunda gerekli alabilecek yatırım maliyetleri hesaplanmış, proseslerden en verimli ve en kârlı olanı, çeşitli kapasiteler için ekonomik analizler yapılarak saptanmıştır.
Soda aah ia ana of the important chemicals consumed in the world. Soda ash is used in the manufacture of glass, chemicals, detergents, pulp, paper and in mater treatment. It is the third important chemicals in the chemical industry after sulfuric acid and ammonia. Soda ash is sold in two forms known as light and' danse ash L^ash is a light, powdery precipitate. Dense ash is a coarse crystalline material with almost twice the bulk density of light ash. Soda ash is produced in over 39 countries by the Solvay ammonia-soda process synthetically or by using natural sodium carbonate suorces such as trona mineral In 1791, IMicola Le Blanc developed black ash from salt, sulfuric acid, coal and limestone. This process was used until 1B63. Then Ernest Solvay developed a a method for producing soda ash from salt, coke, and limestone with ammonia as a catalyst. Synthetic soda ash production began to decline in the late1970's. This was due to high operating costs and waste disposal problems. Since soda ash was used a major component in the chemical industry, an alternate method of producing soda ash was necessary. And now, the natural soda ash production has been rising rapildly. Naturally, soda ash can be produced from some minerals or lakes. Minerals that contain sodium are thermonatrite trona, natron, nahkolit, dawsonite, gaylousite, shortite and burkeite. Sodium carbonate is common in nature but economic deposits of it are rare due to its solubility. vix Three minerals, natron, thermonatrite and trona are only sodium carbonate minerals commercially mined. An hydrous sodium carbonate is almost never found in nature At earles Lake in. the U.S.A., burkeite and hanskite are important in the upgrading process used for natural brines recovered there. Dther minerals such nahcolite and dawsonite are important as accessories. Natural soda sources such as trona mineral or sodium carbonate-rich brines found primarily in the U.S., Mexico, Soviet Union, Kenya, China and Turkey. World soda ash production has now stagnated at a rate of 29m tpa. Overcapacity has led to competition between traditional synthetic soda ash manufacturers of western Europe and the Eastern Bloc, and the natural producers of the U.S.A. which have been working the vasti trona reserves in Wyoming for the last 3D years. To date, thiB competition has been concentrated in the export markets to South East Asia, Latin America and South Africa synthetic soda ash accounts for 75% of total world output and, as these operations are generally located close to their markets, enjoy low distribution cost. But companies mining natural sources of soda ash have an advantage in much cheaper production costs. Both types of soda ash producers are having to adapt to new economic conditions. As consumption of soda ash in ma jor end-use applications in industrialised countries continues to fall flat, new oppartunities are being taken in developing countries as they continue to build an industrialised base and improve infrastructure. In Turkey, soda ash is produced synthetically by Soda Sanayi in Mersin Soda Sanayi, is a joint venture between Türkiye İş Bankası, glass manufacturer Türkiye Şişe ve Cam Fabrikaları and Sümerbank, and was establis hed in 1975. This one of the most modern soda ash facilities in the world. It applies the Solvay process, the latest technology for the manuacture of soda ash. The company manufactures light and dense soda ash, refined sodium bicarbonate, and sodium silicate. Mersln's name plate capacity is 330DDD tpa of soda ash and 20Ü0D tpa of sodium silicate. The soda ash has a minimum Na2C03 content of 99.1 % and a chloride level not higher than D.*+ %. Turkey does not require another soda ash facility to serve current domestic demand. 'However in 1979, the Mineral Research and Exploration Institute (M.T.A). found the trona deposit near Beypazarı during coal Vlll exploration studies. Beypazarı Trana deposit is located approximately 15 km. North-West of Beypazarı in Central Anatolia. The total deposit sur face area is about 8 kmz. Field tests related with geology and hydorolgy mas completed by M.T.A. and the resource uas transferred to Etibank which is state mining company^ in 1983. The studies showed that trona is present 150-^+00 m in deep, layers which are thicker and richer in quality compared to the onesin Wyoming (U.S.A.) Total reserve of the deposits is about 21D millions tons. The average grade of deposit is 85 % trona. The whole trona deposit consits of thirteen different layers and the thickness of the layers change between D.7-6.D m. Beypazarı trona mineral, due to its chemical content, can be processed more easily than Wyoming trona containing 8-1D % NaCl, l\lazSD, content. This resource will allow the natural production of chemicals such bb soda, sodium hyroxide and other sodium derivatives for about a hundred yeras. The possibilities of underground and soluiton mining methods has been considered by Etibank If this project proceed, it could result in substantial changes in the European soda ash market. By the time such a project reaches fruition Turkey could be a full member of the EEC (it is already an associate member). This would open a large market currently supplied by Solvay plants and limited imports of trona from the U.S.A. EEC anti-dumping measures have so far restricted European market development of the U.S. natural soda ash producers. Two processes are used in Wyoming to produce marke table product: Sesquicarbonate and Monohydrate. Both are designed to remove shortite, clay, pyrite and other solids. The basic difference between the two is the initial step. The sesquicarbonate process begins by dissolving trona ore to produce sodium sesquicarbonate cryatalla. During, monohydrate treatment, the ore is calcined before being dissolved. The latter is now the dominant process, although the sesquicarbonate technique was the first to be used. In sesquicarbonate process, trona is crushed and dissolved in the natural state. And all subsequent on the sesquircarbonate solu tion, sesquircabonate crystals are converted to soda ash by calcination. In monohyrate process, Dfter crush ing, the trona ore is first calcined and all subsequent clarification and crystallization takes place on a mono hydrate solution. Monohydrate crystalls are produced by evaporative crystallization. These crystals are conver ted to soda ash by calcination. IX Bath Manohydrate and Sesquircarbonate Processes are applied as conventional mining technique in Wyoming by FMC Corporation. An alternative technique to recover trona deposit ia «olutlun mining technique. DnR nf the first solution mining of trona patents was issued to Robert D. Pike in 19^5. When a predecessor company to FMC conducted a signlewell solution mining trial in 19^5_, the results mere so dissappo inting that the approach was considered impractical and abandoned in favor of under ground mining (conventional techniquue). In 19B0, FMC Corporation installed a pilot plant at Westvaco. They began producing commercial quantities of soda ash from the solution mining in October 1985. Company estimates that production casts for solution mining will be 25% lower than that required for conventional mining. Sesquicarbonate and Manohydrate Processes are com mercial processes for producing soda ash from trona. These tua processes can be considered for Turkish trona. Processes should be designed separately so that a plant is established. One of them can be selected by comparing their capital cost estimations. If the project is pro ceeded and soda ash is ;praduced from trona by Sesquicar bonate or Manohydrate method, substantial changes "in the world soda ash market will be seen. The development of a complete plant desing requires consideration of many different subjects. The role of casts and the design Qf individual pieces of equipment Is equally important. In addition, many other factors must be considered, such as plant location, plant layout plant operation and control, utilities, structural design storage, materials handling, waste disposal, health and safety, patents and legal restrictions. A plant design obviously must present a process that : is capable of operating under conditions which will yield a profit. Since net profit equals total income minus all expenses, it is essential that the many diffe rent types of cost involved in manufacturing processes should be awared. Money must be paid out for direct plant expenses, such as those for raw materials, labor and equipment. In addition, many other indirect expenses are incurred, and these must be included if a complete analysis of the total cost is to be obtained. Some examples of these indirect expenses are administrative salaries, product-distribution costs, and costs for interplant communications. A capital investment is required far any induatrial pracesa, and determination af the necessary investment îa an important part of a plant deaign project. The to- tal investment far any pracesaconaista. of the fixed- capital investment far the physical equipment and faci- ties in the plant plua the uıarking capital far maney uhich must be availabl ta pay salaries, keep rau mate- rials and praducta an hand, and handle ather special items requiring a direct caat autlay. Thus, in an analy- sis af casts in induatrial proceaaea, capital-inveatmest costs, manufacturing caata, and general expenaes includ- ing income taxea muat be taken inta canaideratian. Ecanamic analyaia and evaluation are often needed aa a guide ta planning nem capacity and in atuding ham changes in plant size, selling price and demand and alternative pranesaea ör equipment might affect profita- bility. in thia atudy, computer adideddesign and cast esti- matian model uere develaped far the Manahydrate and Seaquicarbanete Proceaaes ta praduce şada ash from the trana mineral. Ta achieve thia scape, firstly flau aheeta af theae tua pracesaea uere prepared, material and energy b a l a n c e o aquatinaa uıere dsriueü. Becatıüly, the equipments in the flou sheets uere listed and the aize af the equipmenta uere determined far the different praductian af aada ash capacitiea. Finaly cast analysis uere made and the capital casta, fixed capital, uarking capital, tatal capital, manufacturing expenses, praduct cast, net artnual profit and rate of return were deter¬ mined far bath Manahydrate and Seaquicarbanate Processes. As the main reaults of this study, the tatal capital. inveatment caat af a soda ash plant uıith 5DD.DDD tons per year capacity fram 95% trana öre by Manahydrate process u/aa found 171 billion Tl. Each 250.000 tons/year increaae in this capacity, caused 45-5G billian TL increase in cast. The investment cost af Sesquicarbanate pracess is higher uhen campared uith the Manohydrate praceas due ta same additianal equipment uaed specifically in this methad, which are grinder,vacuum crystallizer and ateam jet ejectar.far crystallizer, ete. it mas observ/ed that, far Manahydrate Pracess, a decrease in öre grade fram 95% ta 85 % caused 5-6 % increase in tatal investment cast, far seueral praductian capacities. * xı This study also indicated that the Monohydrate Process is mare advantages than Sesquicarbonate Process. The advantages of Monahydrate Process can be summarized with louier investment, production and unit costs and as a consequent of these, with a higher profit, uhen compa red with Sesquicarbonat Process. As a last conclusion of this work, it was proved by all the calculations, that soda production from trona ore is much cheaper than the synthetic soda ash production. Therefore, if Beypazarı Trona deposits are recovered by Monahydrate Process then it would be possible to produce soda ash at low cost and this would be a great advantages for Turkey to find a very large foreign market for this product.
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1990
Anahtar kelimeler
Kimya Mühendisliği, trona minerali, soda üretim prosesleri, üretim teknolojisi, chemical engineering, trona mineral, soda ash production processes, production technology