Belediye katı atıklarının termal yöntemlerle bertarafı teknolojik ve ekonomik incelenmesi

Abstract

Dünyada ve ülkemizde, tükenmekte olan enerji kaynaklarının korunması ve sürdürelebilir büyüme için, yenilenebilir enerji kaynaklarına verilen önem gün geçtikçe artmaktadır. Öte yandan, artan şehirlesme ile birlikte, evsel ve endüstriyel atıkların bertarafı da önemli bir çevresel sorun haline gelmiştir. Biyokütleden enerji üretimi, her iki sorunun çözümüne katkıda bulunabilecek olması nedeni ile diğer yenilenebilir enerji kaynakları içerisinde ayrı bir yere sahiptir. Çalışmamızın ilk kısmında yenilebilir enerji kaynakları çok temel olarak tanıtılmış olup, Türkiye'de kaynak bazlı enerji kurulu güçleri, enerji fiyatları oluşumu ve destekleme mekanizmaları hakkında temel bilgi verilmiştir. Çalışmamızın temeli olan katı atık konusunda uygulanan katı atık yönetimi hiyerarşisi anlatılmıştır. Bu hiyerarşinin üst basamağı depolamadır. Bu sebeple günden güne artan katı atık miktarı için düzenli depolama sahaları günden güne dolmakta, yeni saha arama çalışmaları ve yeni yer işgalleriyle sonuçlanmaktadır. Düzenli atık depolama tesisleri yerine yapılacak olan katı atık bertaraf tesisi ile hem kullanılabilir katı atıklar ayrıştırılacak hem de kalan yüksek kalorifik değerli yakıtın (RDF, Refuse-Derived Fuel) termal bertarafı ile de enerji üretimi gerçekleştirilecektir. Bir biyokütle olan bu yakıt 0,133 USD/kWh'den YEKDEM kapsamında elektrik satışı gerçekleştirecektir. Biyokütlenin biyolojik ve termal bertaraf yöntemleri incelenmiştir. Biyolojik yöntem olan biyometanizasyon sonucu katı atık depolama sahası içerisinde ciddi miktarda metan gazı alınmış katı atık içermekte olup saha tekrar kullanılamayacaktır. Termal yöntemlerde ise piroliz, gazlaştırma ve yakma işlemleri anlatılmıştır. Temel olarak teknolojileri tanıtılmış olup, diğerlerine göre daha bilinir ve ilk yatırım maliyeti diğerlerinden düşük olan yakma sistemi seçilerek mühendislik hesaplamaları yapılmıştır. Bu yöntemde katı miktarlarında hacimce %80-90 azalma elde etmek mümkündür. Çıkan kül ise dolgu malzemesi olarak kullanılabilecektir. Atıktan enerji üretim tesisi, öncelikle hukuki boyutu ele alınmış, tesisin operasyona geçebilmesi için gerekli ve zorunlu olan elektrik üretim lisansı, katı atık bertarafı lisansı ve çevre etki değerlendirme raporları gerekliliği incelenmiş ve gösterilmiştir. Mühendislik yaklaşımı ise temelde buhar kazanı, buhar türbini, kondenser ve diğer ekipmanlardan oluşacaktır. Buhar türbininde buhar çekiş durumuna göre ekonomik açıdan analiz yapılmış olup, türbin tipine karar verilmiştir. Soğutma suyu tedariğine göre analiz yapılmış olup, kondenser tipi belirlenmiştir. Temel mühendislik hesaplamaları ideal Rankine çevrimi doğrultusunda yapılmıştır. Finansal olarak incelenen bu yatırım, ürettiği elektriğin tamamen satışı kabulü yapılarak, nakit akışları ve kredi ödemeleri hesaplanmış, tablolarda gösterilmiştir. Yatırım değerlendirme kriterleri olan yatırım geri dönüş süresi (RoI) ve iç verim oranı (IRR) hesaplanarak yatırımın yapılabilirliği gösterilmiştir.Bütün bu inceleme ve hesaplamalar sonucunda yatırım feasible görünmekte olup, farklı konularda getirilen öneriler ve yapılacak iyileştirmeler sonucunda ciddi bir tesis olacak ve büyük bir sorun olan katı atıklar konusunda çözüm aracı olacaktır

Nowadays, the importance of renewable energy sources is increasing day by day because of the endangering fosil energy sources and sustainable growth. On the other hand, disposal of domestic and industrial waste has become a major environmental problem with increasing urbanization. Energy generation from biomass has a crucial place from other renewable energy sources because it may solve both problems.In the first part of this study, renewable energy sources are basically introduced and basic information about resource based installed capacity in Turkey, the general information about energy sector and energy market mechanisms in Turkey through years. Then electricity price formations are shown and renewable energy dupport mechanisms and feed-in tariffs are given. First, the hierarchy of solid waste management has been explained. One of the fundementals, now supported by laws, for Turkey and European Country waste management has been the concept of a waste management hieararchy, where the most covetable option is preventing waste in the first place (not produce the waste) and the least covetable option is to dispose of the waste to landfill without any recovery of either energy or recycled materials. Therefore, landfill fields are filling up day by day because of the increasing amount of solid waste. Moreover, new storage fields are needed and exploration new places. Between these different two choices, there are a wide variety of waste treatment options that may be used as part of a waste management strategy to recover materials (for example furniture reuse, glass recycling or organic waste composting) or generate energy from the wastes (for example through incineration, or digesting biodegradable wastes to produce usable gases).The top step of the hierarchy is storage. Solid waste incineration facilities can be built instead of regular waste storage areas. After separation, high calorific valued RDF(refused derived fuel) can be burned and produced energy. This fuel is classified as a `biomass` and this electricity has fixed feed-in tariff with 0.133 USD/kWh. Biological and thermal disposal methods of biomass have been examined. The result of biometanization, which is one of the biological methods, there is a considerable amount of solid waste which methane degassed in the storage areas. So storage field will not be used again. Pyrolysis, gasification and incineration are described as thermal methods. Incineration is an effective approach to diminish the waste volume and to reduce the landfill space. Incineration plants can be located near the center of gravity of waste generation, therefore reducing the expense of waste transportation. Utilizing the ash from MSW incinerators for ecologically suitable development gives a minimal effort total as well as further lessens the requirement for landfill space. Specifically, incineration of waste containing heavy metals thus on ought to be avoid to keep up an appropriate slag quality. Nonetheless, standard family waste contains little measures of substantial metals which do not promptly filter under field conditions. The nature of waste ought to be checked before it is used. Energy can be recovered for energy or hear production. All waste disposal methods decay organic materials into simple carbon molecules, for example, CO2 (carbon dioxide) and CH4 (methane) at the end. The balance between these two gasses and frame of time for the responses varies by alternative. Incineration gives the most ideal approach to eliminate methane gas discharges from waste management systems. Besides, energy from waste projects gives a substitute to fossil fuel combustion. These are two ways incineration plants help to reduce greenhouse gas emissions. One of the important features of incineration process is that it can be reduced the first volume of combustibles by 80 to 95 percent. Air pollution control remains a major issue in the implementation of incineration of solid waste disposal. In the United States, the expense of best available technology for the incineration facility may be as high as 35 percent of the investment cost. The cost of control systems will, rely on the air pollution regulations existing in a given lesser developing countries. Waste incineration may be valuable when a landfill cannot be sited as a result of an absence of suitable sites or high costed long haulage distances. The Energy Sector, Incineration of MSW is blazingly more costed than controlled landfilling. For a plant to be feasible in financial, costs must be minimized through sales of energy recovered. The essential concern is the end use of the energy produce: region heating, steam, power, or any combination. In this manner, the characteristics of the energy sector have an essential role while considering a MSW incineration plant. Energy sales as in hot water for locale warming purposes - or specifically cases, low pressure steam to large scale industrial consumers near plant, provide for sufficient contracts and guarantees can be arranged - minimizes plant construction expenses and recovers a high rate of energy. Sales of combined power and heat or steam results in a level of energy recovery that is not higher, but the cost and the complexity of the plant are increased. The energy sector is frequently regulated by governmental organizations. Concession to produce and sell power is generally granted to a limited number of public and private operators. An incineration plant set up by another authority or a private organization may experience challenges before gaining the aggrements and approvals. Early co-operation with the end user organizations is accordingly useful. It is most possible when the power can be sold to one customer for its own use or resale again. For instance, the customer might be a electricity distrubution service organization with an existing grid system. Cost of energy is frequently subject to tax collection or are partly subsidized. Pricing may be a political issue requiring a governmental issue. Likewise, in most developed countries, energy costs are controlled by fiscal measures to support power generation based on biomass fuels. Political and socio-economic considerations play an imperative role when fixing the cost of the power that produced by waste. A high price resulting in a reduction of the waste fee favors the waste sector, but low energy prices favor the energy consumers. Then, legal aspects of waste to energy plant are diccussed. After that electricity production license, licensing of disposing of waste, and environmental impact assessment reports, which are compulsory to operate the power plants in Turkey energy sector, were shown. The engineering approach will consist of steam boiler, steam turbine, condenser and other equipments. The turbine type has been decided according to the condition of steam extraction with economical calculations. According to supply of cooling water condenser type has been determined. Basic engineering calculations have been made according to ideal Rankine cycle. The investment is evaluated in financial project calculations. Cash flow and installments were calculated and shown in the tables with sales of all produced electricity. Investment is evaluated with return on investment (ROI) and internal rate of return (IRR) and this power plant investment seems feasible.As a result, this incineration plant investment seems feasible. Morever this plant solves the solid waste storage problems. In this effective plant the renewable and local fuels are used and security of energy supply problem is solved. With this renewable fuel more clean and efficient electricity is produced.