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In power plant industries, boiler feed water (BFW) quality becomes the main parameter for steam generation, which is used for electricity production. To generate standard BFW for power plants, each impurity within water resources should be removed to prevent corrosion and scale deposition by several processes such as sedimentation, coagulation, polishing, and deaeration. Operation conditions that involved high temperature would trigger corrosion as a crucial factor in the maintenance and practical lifetime of the equipment. In the beginning of the operation, PT. Cirebon Electric Power (CEP) used All Volatile Treatment–Reduction (AVT-R) by injection of both ammonia and hydrazine. In order to optimize the operation, the BFW treatment was changed to All Volatile Treatment–Oxidation (AVT-O) that only uses of ammonia and deaerator for removing the dissolved gas. Based on the actual evaluation, AVT technology showed less performance related to corrosion prevention and high chemical consumption. Therefore, PT. CEP tried to implement modification in the BFW treatment, which is AVT technology to Oxygenated Treatment (OT). This paper is to evaluate the effect of those modifications on corrosion prevention and resource-energy saving. The modification into OT showed valuable results that decrease concentration of dissolved Fe from 1 ppb to 0.1 ppb in the deaerator outlet stream. This data reveals that good corrosion prevention can be achieved through the creation of passive layers, hematite Fe 2 O 3 . Oxygen injection into the water circulation system yielded an oxidation atmosphere so that the passive layer, Fe 2 O 3 , was formed. In addition to corrosion prevention, this modification also cut the amount of ammonia injection into the system from 2 ppm to 0.12 ppm. Reduction of that ammonia injection provides other benefits such as decreasing the volume of resin regeneration, which becomes only twice a month. This situation also created other benefits such as reducing the regeneration water, chemicals, and wastewater. Thus, the modification could establish the electricity production by PT. CEP more environmentally friendly and sustainable . A B S T R A K Pada operasi PLTU, kualitas boiler feed water (BFW) menjadi parameter yang krusial untuk menghasilkan steam yang akan digunakan untuk memproduksi listrik. Untuk mendapatkan BFW sesuai dengan standar yang ada, maka pengotor di dalam air baku industri harus dihilangkan karena dapat menyebabkan korosi dan pembentukan kerak, baik pada pipa maupun peralatan. Kondisi operasi yang melibatkan steam pada suhu tinggi menyebabkan korosi menjadi masalah yang krusial terutama terkait dengan maintenance dan umur efektif pabrik. Pada awal berdirinya, PT. Cirebon Electric Power (CEP) menggunakan teknologi All Volatile Treatment–Reduction (AVT-R) dengan injeksi amonia dan hidrazin. Selanjutnya, dilakukan optimasi melalui perubahan proses menjadi All Volatile Treatment–Oxidation ( AVT-O) dengan hanya menginjeksikan amonia dan mengoptimalkan fungsi deaerator untuk menghilangkan pengotor dissolved gas. Berdasarkan data lapangan, teknologi AVT yang digunakan kurang memberikan pencegahan korosi yang baik dan juga jumlah bahan kimia yang digunakan masih relatif banyak. Agar lebih ramah lingkungan dan handal, PT. CEP berusaha untuk melakukan modifikasi terhadap pengolahan boiler feed water (BFW) dari yang semula menggunakan teknologi AVT-O menjadi Oxygenated Treatment (OT) . Penelitian ini bertujuan untuk mengevaluasi dampak modifikasi sistem AVT menjadi OT pada pencegahan korosi dan juga penghematan sumber daya. Modifikasi sistem AVT-O menjadi OT berhasil menurunkan konsentrasi dissolved Fe dari 1 ppb menjadi 0,1 ppb pada BFW. Hal ini menunjukkan terjadinya peningkatan pencegahan korosi melalui pembentukan double protective layer yang merupakan kombinasi magnetite (Fe 3 O 4 ) dan hematite (Fe 2 O 3 ). Injeksi oksigen ke dalam sistem mengubah kondisi air menjadi suasana oksidasi sehingga mampu mengubah dan membentuk lapisan baru sebagai pencegahan korosi. Selain pencegahan korosi, modifikasi ini juga berhasil menurunkan jumlah injeksi amonia dari 2 ppm menjadi 0,12 ppm dalam siklus air yang ada. Penurunan jumlah injeksi amonia ini akan memberikan keuntungan beruntun berupa berkurangnya frekuensi regenerasi resin dari semula 8 menjadi 2 kali perbulan. Kondisi ini akan menghasilkan penghematan sumber daya berupa kebutuhan air untuk regenerasi, bahan kimia amonia, dan beban pencemaran. Oleh karena itu, modifikasi ini telah membuat proses produksi listrik di PT. CEP lebih ramah lingkungan dan berkelanjutan. Kata kunci: All Volatile Treatment (AVT); efisiensi energi; korosi boiler ; Oxygenated Treatment (OT)

High-temperature corrosion of critical components such as water walls and superheater tubes in biomass/waste-fired boilers is a major challenge. A dense and defect-free thermal spray coating has been shown to be promising to achieve a high electrical/thermal efficiency in power plants. The field of thermal spraying and quality of coatings have been progressively evolving; therefore, a critical assessment of our understanding of the efficacy of coatings in increasingly aggressive operating environments of the power plants can be highly educative. The effects of composition and microstructure on high-temperature corrosion behavior of the coatings were discussed in the first part of the review. The present paper that is the second part of the review covers the emerging research field of performance assessment of thermal spray coatings in harsh corrosion-prone environments and provides a comprehensive overview of the underlying high-temperature corrosion mechanisms that lead to the damage of exposed coatings. The application of contemporary analytical methods for better understanding of the behavior of corrosion-resistant coatings is also discussed. A discussion based on an exhaustive review of the literature provides an unbiased commentary on the advanced accomplishments and some outstanding issues in the field that warrant further research. An assessment of the current status of the field, the gaps in the scientific understanding, and the research needs for the expansion of thermal spray coatings for high-temperature corrosion applications is also provided.

The present study investigates the initial corrosion behaviour of HVAF-sprayed NiCr, NiAl and NiCrAlY coatings in two different environments, O 2 + H 2 O and O 2 + H 2 O + KCl at 600 °C for up to 168 h in order to evaluate the possibility of utilizing such coatings in biomass- and waste-fired boilers. SEM/EDX analysis showed that all coatings displayed a protective behaviour in O 2 + H 2 O. Upon addition of KCl (O 2 + H 2 O + KCl), the corrosion behaviour of the NiCr coating drastically changed as it formed a thick oxide layer and displayed major chlorine diffusion down to the substrate. The NiCrAlY coating displayed a significantly better corrosion resistance with only minor oxide formation. The NiAl coating exhibited a protective behaviour similar to when exposed in the absence of KCl indicating that a thin protective oxide has formed on the coating surface. The performance of the NiAl and NiCrAlY coatings is promising for future studies with long-term exposures in more corrosive environments such as in a biomass- and waste-fired boiler. © 2019, The Author(s).

Due to ongoing developments in the EU waste policy, Waste-to-Energy (WtE) plants are to be optimized beyond current acceptance levels. In this paper, a non-exhaustive overview of advanced technical improvements is presented and illustrated with facts and figures from state-of-the-art combustion plants for municipal solid waste (MSW). Some of the data included originate from regular WtE plant operation – before and after optimisation – as well as from defined plant-scale research. Aspects of energy efficiency and (re-)use of chemicals, resources and materials are discussed and support, in light of best available techniques (BAT), the idea that WtE plant performance still can be improved significantly, without direct need for expensive techniques, tools or re-design. In first instance, diagnostic skills and a thorough understanding of processes and operations allow for reclaiming the silent optimisation potential. publisher: Elsevier articletitle: Optimising energy recovery and use of chemicals, resources and materials in modern waste-to-energy plants journaltitle: Waste Management articlelink: http://dx.doi.org/10.1016/j.wasman.2013.05.026 content_type: article copyright: Copyright © 2013 Elsevier Ltd. All rights reserved. ispartof: Waste Management vol:33 issue:11 pages:2416-2424 ispartof: location:Venice, Italy status: published

When SL Dolly was recovered from Ullswater after being submerged for 67 years, the wrought iron boiler was found to have surprisingly little corrosion. This article describes the results of a project to investigate the reasons for this behaviour and determine whether it was a property of the wrought iron or a consequence of the lakebed environment. Weight loss measurements and electrochemical impedance spectroscopy were used to compare the corrosion rates of wrought iron and modern boiler steel exposed to tap water and samples of lake water and lakebed sediment. A corrosion probe was used to make in situ linear polarisation resistance measurements at the spot where Dolly sank. The corrosion rate of wrought iron on the lakebed was estimated to be in the range 0à ·018â  0à ·030 mm year-1, which corresponds to a metal loss of 1à ·2â  2à ·0 mm over the 67 year period; this metal loss is consistent with the condition of the boiler. The effects of microstructure, material composition and water chemistry are considered in detail, and it is concluded that the low oxygen content and the low concentration of dissolved solids in the lake water were the underlying causes of the observed corrosion be

The oxidation behaviour of manual metal arc welded (MMA) 2.25Cr-1Mo steel was studied in a potassium sulphate-sodium chloride salt mixture. The presence of this salt mixture accelerated the attack. The variation of weight gain with time indicated a parabolic growth of oxides. The outer layers consisted of oxides whereas inner layers showed the presence of sulphides. This is an example of hot corrosion attack wherein the degradation resulted in internal oxidation and sulphidation of the material.