Publication: Kakao atomize kurutma tesisinde aşınma problemleri ve önlemleri
Abstract
Öğütülürek istenen boyutlara indirilen kako partikülünün rutubeti atomize kurutma tesisinde kurutularak giderilir. Atomize kurutma tesisi gıda sanayinin muhtelif kollarında kullanılmaktadır. Atomize kurutma tesisi; yüksek basınç pompası, alçak basınç pompası, vantilatör, hava ısıtıcı brülör, soğutma vantilatörü, püskürtme memeleri (atomizerler), pnömatik çekiç, kurutma haznesi, torbalı filtreler, emiş vantilatörü (blower), helezon (sonsuz vida), rotary valf (mal alma kilidi) ve kumanda panosundan meydana gelir. Yüksek basınç pompasının supap-yuvalarına çok çabuk aşınması bu tesisin ana problemidir. Üretim kayıpları ve supap-yuvaların ithal edilmesinden kaynaklanan döviz giderleri önemli meblağlara ulaşmaktadır. Bu çalışmada, kakao kurutma tesisinde yüksek basınç pompasının supap-yuva elemanlarının aşınma problemi incelendi. Supap-yuvaların malzeme cinsi ve spektral analizi, talaşlı üretimleri, ısıl işlemleri, yüzey pürüzlülük değeri, aşınma ömürleri, geri dönüşümü, yüzey sertlikleri ve maliyetleri deneysel olarak yapıldı. Supap-yuva elemanları, %1'in üzerinde Mangan içeren otomat çeliği, %1'in altında Mangan içeren alaşımsız çelik (ıslah çeliği), alaşım elementleri toplamı %5'in altında olan alaşımlı çelik (sıcak iş çeliği), alaşım elementleri toplamı %5'in üzerinde olan alaşımlı çelik (soğuk iş çeliği) yüksek hız çeliği ve iki cins sinterlenmiş karbürden üretildi. Ostenitik paslanmaz çelikten üretilmiş olan supap-yuvaları orijinal Lewa pompa GmbH. olduğundan ayrıca üretimi yapılmadı. Orijinal supap-yuvaların spektral analizi, aşınma ömürleri, üretim kapasitesi incelendi ve maliyet analizi yapıldı. Çeliklerin her birinden numune alındı, ayrı ayrı spektral analiz yoluyla kimyasal kompozisyonları kontrol edilerek, üreticinin kataloğunda belirtilen kompozisyona uygun olduğu görüldü. Deneysel çalışmalar için seçilen çeliklerden üretilen supap-yuvaların tornalama işlemleri, ısıl işlem sertleştirmesi, sertlik kontrolu, profil taşlama, Ra yüzey pürüzlülüğü değerinin 1 mikrona indirilmesi (Lepleme), yüzey pürüzlülüğü ölçme, Krom/ Titanyum Nitrür kaplama, kaplanmış yüzey sertliği ölçme işlemleri yapıldı. İki cins sinterlenmiş karbür, Böhler Sert Maden Sanayi ve Ticaret A.Ş.'de yaptırıldı. Torna ve ısıl işlem dışındaki işlemler aynen sinterlenmiş karbürlerede uygulandı. İşlemler sonrası elde edilen yüzeyin mikroyapısı tespit edildi ve yorumlandı. Her cins supap-yuvanın üretim maliyeti analizi yapıldı. Yedi ayrı cins çelik, iki cins sinterlenmiş karbürden takım olarak yapılan supap-yuvaların ömürleri, üretilen toz kakao miktarıyla tespit edildi. Üretilen supap-yuvaların, ostenitik paslanmaz çelikten yapılmış orijinal Lewa supap-yuvalarla mukayesesi yapıldı. Orijinal supap-yuvaların çalışma zamanı ve üretim miktarını optimum seviye olarak kabul edersek: Optimum seviye üzerinde, yalnız yüksek hız çeliğinden yapılmış supap-yuvalardan maximum ömür ve yüksek üretim sağlandı. Yüksek hız çeliğinden üretilen supap-yuvalar 3 kez geri dönüşüm edildi ve üretim maliyetleri gözden geçirildi. Bu çelikten mamul supap-yuvaların ömrü azaldığından ve üretilen toz kakao miktarı düştüğünden 4. kez geri dönüşüm işlemine elverişli olmadığı görüldü. Böhler GB 56, 1.0737, 1.7225, 1.2550, 1.2379 malzeme cinsinden üretilen supap yuvaların optimum seviye altında, Böhler GB 03 malzemeninde az üstünde olduğu saptandı. Krom nitrür kaplanmış ve kaplanmamış yüksek hız çeliği supap-yuvaların, ömür ve üretim artışı mukayesesi yapıldı. Krom Nitrür kaplı olanlarda %36,3 ila %52,8 ömür ve üretim artışı sağlandı. Deneyler neticesinde; maximum ömür, maximum toz kakao üretimi ve en düşük maliyetin 1.3343 standart no'lu yüksek hız çeliğinden yapılan supap-yuvalarla elde edilebileceği tespit edildi. Tezin deneysel çalışmaları sırasında Ülker Gıda Sanayi ve Ticaret A.Ş., Üstün Gıda Sanayi ve Ticaret A.Ş., İmes Sanayi Sitesi Kosgeb İstanbul Danışmanlık ve Kalite Geliştirme Merkezi, Doğu Sanayi Sitesi, Kosgeb İstanbul Danışmanlık ve Kalite Merkezi, Marmara Üniversitesi Teknik Eğitim Fakültesi Malzeme Bilgisi Labratuvarlarından faydalanıldı.
Cocoa is grinded and the regnired dimensions of the cocoa particle is obtained. Its humidity is removed in the atomized drying installation. This drying installation is used in varions branches of the food industry. The atomized drying installation consists of a high pressure pump, a low pressure pump, a vantilator, an air heater, a cooling fan, spraying nozzles, pneumatic hammer, drying chamber, filters, blowers, a rotary valve and a control panel. The main problem of this installation is that the valve beds of the high pressure pump wears very quickly. Production losses due to this problem are very high. In this study, the wearing problem of the valve beds in the high pressure pump in the cocoa drying installation was investigated. The materials of valve beds and spectral analysis, chip removing processes, heat treatment processes, surface roughness volues, wear life, reusing, surface hardness and the costs were investigated experimentally. Valve bed elements were made of steel with more than 1% manganese, steel with less than 1% manganese, steel with less than 5 % alloys (hot working steel), steel with more than 5% alloys (cold working steel), high speed steel and two kinds of sintered carbide. Since valve beds made of austenite steel are original Lewa Pumps GmbH, these were not produced. Spectral analysis, wear life, production capacity of the original valve beds were investigated and the cost analysis was made. A sample was taken from each steel, chemical composition of each was checked by spectral analysis and it was seen that its composition was the same as mentioned in the manufacturer's catalogue. The valve beds of the steels chosen for the experimental studies were lathed, hardened by heat treatment, hardness were checked, surface roughness were reduced down to 1 mikron, Chromium/ Titanium Nitrite coating was made and surface hardness measurement prosesses were made. Two kinds of sintered carbide were made in Böhler Sert Maden Sanayi ve Ticaret Plc. Except lathing and heat treatment processes, all the activities were applied to the sintered carbides. The micro structures of the surfaces after the processes were determined and analysed. The production cost analysis of each kind of valve bed was made. The wear life of valve beds made of seven different kinds of steel and two different kinds of sintered carbide was obtained and the amount of powdered cocoa product was determined. A comparason of the produced valve beds with the original Lewa valve beds made of austenite stainless steel were made. If we assume that the wear life and the production output of the original valve beds are optimum, maximum wear life and high production output was only obtained using valve beds made of high speed steel. Valve beds made of high speed steel were reused 3 times and the production costs were examined. Since the wear life reduced and the amount of powdered cocoa product dropped, it was seen that rensing this steel for the 4 th time was not suitable. The valve beds made of Böhler GB 56, 1.0737, 1.7225, 1.2550 and 1.2379 materials were below the optimum level while the beds made of Böhler GB 03 material were Just above the optimum level. A comparison of the valve beds made of high speed steel material with or without Cromium Nitrite coating was made according to wear life and production increase. An increase of 36,3% to 52,8% in wear life and production output was obtained with the steel coated by Cromium Nitrite. As the result of the experiments, it has been determined that maximum wear life, maximum powdered cocoa production and minimum cost is obtained by using the valve beds made of No. 1.3343 high speed steel. During the experimental studies, Ülker Food Industry and Trade Plc, Üstün Food Industry and Trade Plc, KOSGEB İstanbul Consulting and Quality Development Centre, İMES Industrial Estate, Doğu Industrial Estate and Materials Science laboratories of the Technical Education Faculty of Marmara University were used.
Cocoa is grinded and the regnired dimensions of the cocoa particle is obtained. Its humidity is removed in the atomized drying installation. This drying installation is used in varions branches of the food industry. The atomized drying installation consists of a high pressure pump, a low pressure pump, a vantilator, an air heater, a cooling fan, spraying nozzles, pneumatic hammer, drying chamber, filters, blowers, a rotary valve and a control panel. The main problem of this installation is that the valve beds of the high pressure pump wears very quickly. Production losses due to this problem are very high. In this study, the wearing problem of the valve beds in the high pressure pump in the cocoa drying installation was investigated. The materials of valve beds and spectral analysis, chip removing processes, heat treatment processes, surface roughness volues, wear life, reusing, surface hardness and the costs were investigated experimentally. Valve bed elements were made of steel with more than 1% manganese, steel with less than 1% manganese, steel with less than 5 % alloys (hot working steel), steel with more than 5% alloys (cold working steel), high speed steel and two kinds of sintered carbide. Since valve beds made of austenite steel are original Lewa Pumps GmbH, these were not produced. Spectral analysis, wear life, production capacity of the original valve beds were investigated and the cost analysis was made. A sample was taken from each steel, chemical composition of each was checked by spectral analysis and it was seen that its composition was the same as mentioned in the manufacturer's catalogue. The valve beds of the steels chosen for the experimental studies were lathed, hardened by heat treatment, hardness were checked, surface roughness were reduced down to 1 mikron, Chromium/ Titanium Nitrite coating was made and surface hardness measurement prosesses were made. Two kinds of sintered carbide were made in Böhler Sert Maden Sanayi ve Ticaret Plc. Except lathing and heat treatment processes, all the activities were applied to the sintered carbides. The micro structures of the surfaces after the processes were determined and analysed. The production cost analysis of each kind of valve bed was made. The wear life of valve beds made of seven different kinds of steel and two different kinds of sintered carbide was obtained and the amount of powdered cocoa product was determined. A comparason of the produced valve beds with the original Lewa valve beds made of austenite stainless steel were made. If we assume that the wear life and the production output of the original valve beds are optimum, maximum wear life and high production output was only obtained using valve beds made of high speed steel. Valve beds made of high speed steel were reused 3 times and the production costs were examined. Since the wear life reduced and the amount of powdered cocoa product dropped, it was seen that rensing this steel for the 4 th time was not suitable. The valve beds made of Böhler GB 56, 1.0737, 1.7225, 1.2550 and 1.2379 materials were below the optimum level while the beds made of Böhler GB 03 material were Just above the optimum level. A comparison of the valve beds made of high speed steel material with or without Cromium Nitrite coating was made according to wear life and production increase. An increase of 36,3% to 52,8% in wear life and production output was obtained with the steel coated by Cromium Nitrite. As the result of the experiments, it has been determined that maximum wear life, maximum powdered cocoa production and minimum cost is obtained by using the valve beds made of No. 1.3343 high speed steel. During the experimental studies, Ülker Food Industry and Trade Plc, Üstün Food Industry and Trade Plc, KOSGEB İstanbul Consulting and Quality Development Centre, İMES Industrial Estate, Doğu Industrial Estate and Materials Science laboratories of the Technical Education Faculty of Marmara University were used.