Section 5. Tables of Suggested Water Chemistry Targets

Consensus water chemistry controls for the six types of steam generator systems are presented in Tables 1 through 7. The tabulated information is categorized according to operating pressure ranges because this is the prime factor that dictates the type of internal water chemistry employed, the normal cycles of feedwater concentration, the silica volatility, and the carryover tendency. The difference between steam and water densities decreases with increasing pressure and temperature; therefore, separating the steam/water phases completely in the boiler drum becomes increasingly difficult to achieve. Since the tendency to carryover is greater at higher operating pressures, it is necessary to maintain lower boiler water contaminant concentrations to meet the same steam purity target.

Section 1. Introduction

This document has been prepared by the Water Technology Subcommittee of the ASME Research and Technology Committee on Steam and Water in Thermal Systems as a consensus of proper current operating practices for the control of feedwater and boiler water chemistry in the operation of industrial and institutional, high duty, primary fuel fired boilers. These practices are aimed at minimizing corrosion, deposition, cleaning requirements, and unscheduled outages in the steam generators and associated condensate, feedwater and steam systems for boilers, and steam system components which are currently available. This publication is an expansion and revision of the operating practice consensus documents previously issued by the Committee [1-3]. The tabulated values herein update and replace the ones previously published. Titles have been edited and clarified. The text has been reordered and modified where necessary. THE TEXT IS OF PRIME IMPORTANCE AND SHOULD BE CONSIDERED FULLY BEFORE USING THE TABULATED VALUES. One Appendix has been added to provide additional guidance.

Section 4. Water Chemistry Parameters

The maintenance of specified feedwater and boiler water chemistry must be well regulated and documented by frequent analysis and record keeping. Normally, a combination of online analyzers and grab sample measurements is used to ensure proper chemistry control. Guidance on sample collection and conditioning is provided in “Consensus on Operating Practices for the Sampling and Monitoring of Feedwater and Boiler Water Chemistry in Modern Industrial Boilers” [7].

Back Matter

This back matter contains the Section 6: References, Glossary and Appendix A. Estimating Boiler Water Silica Limits.

Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Industrial and Institutional Boilers

The Water Technology Subcommittee of the ASME Research and Technology Committee on Water and Steam in Thermal Systems, under the leadership of Mr. Robert D. Bartholomew has revised the Consensus on Operating Practices for the Control of Feedwater Boiler Water Chemistry in Modern Industrial Boilers, first published in 1979 with prior revisions published in 1994 and 1998. The task group consisted of a cross section of manufacturers, operators, chemical treatment contractors and consultants involved in the fabrication and operation of industrial and institutional boilers. Members of this group are listed in the acknowledgments. This current document is an expansion and revision of the original, with reordered and modified texts where considered necessary. While significant revisions have been incorporated, it is recognized that there are areas of operating practice not addressed herein. Additional information is available from the references. It is the plan of the ASME Research Committee to continue to review this information, and revise and reissue this document as necessary to comply with advances in boiler design and water conditioning technology.

Reverse Osmosis Treatment of Wastewater for Reuse as Process Water—A Case Study

The aim of this work was to purify mixed wastewater from three different production processes in such a manner that they could be reused as process water. The maximum allowed concentrations (MAC) from the Environmental Standards for emissions of substances released into surface water were set as target concentrations. Wastewaters contained solid particles, sodium, aluminium, chloride, and nitrogen in high amounts. Quantitatively, most wastewaters were generated in the production line of alumina washing. The second type of wastewater was generated from the production line of boehmite. The third type of wastewater was from regeneration of ion exchangers, which are applied for feed boiler water treatment. The initial treatment step of wastewater mixture was neutralisation, using 35% HCl. The precoat filtration followed, and the level of suspended solids was reduced from 320 mg/L to only 9 mg/L. The concentrations of ions, such as aluminium, sodium and chlorides remained above the MAC. Therefore, laboratory reverse osmosis was applied to remove the listed pollutants from the water. We succeeded in removal of all the pollutants. The concentration of aluminium decreased below 3 mg/L, the sodium to 145 mg/L and chlorides to 193 mg/L. The concentration of nitrate nitrogen decreased below 20 mg/L.

Rancang Bangun Sistem Pengolahan Air Umpan Boiler Untuk Pengembangan Praktikum Sistem Pembangkit II

Penelitian ini bertujuan untuk menyediakan fasilitas sistem pengolahan air umpan boiler (water treatment) yang sesuai dengan sistem PLTU di Laboratorium Konversi Energi. Adapun langkah-langkah rancang bangun ini diawali dengan survey lapangan, studi literatur, desain kemudian perakitan sistem pengolahan air umpan boiler. Pengumpulan data dilakukan dengan pengujian pada air baku dan air umpan boiler kemudian pengujian filter pasir silika, sedangkan analisa data dilakukan dengan membandingkan data hasil pengujian dengan standar air umpan boiler yang ada. Hasil yang diperoleh yaitu tersedianya sistem pengolahan air umpan boiler dengan menggunakan filter pasir silika dan unit pelunak air yang mampu mengubah sifat air baku dari sadah menjadi lunak. Berdasarkan hasil pengujian sistem pengolahan air umpan boiler, karakteristik air hasil olahan sudah memenuhi standar air umpan boiler, kecuali pada parameter pH.

Perancangan Alat Total Dissolved Solid (TDS) Monitoring pada Air Boiler berbasis Mikrokontroler di Pabrik Kelapa Sawit Naga Sakti

Steam is a utility that have an essential function in palm oil production. Steam is mainly used in steam turbine to move the generator to produce electricity. Steam also has a lot of other functions such as heating cold oil in storage tank, heating coil in kernel drying, etc. Steam is produced in a machine called boiler. Boiler require a treated feed water as an input. To maintain boiler performance and lifetime, one need to control the TDS (Total Dissolved Solid) in boiler feed water in a range of 2100 2500 ppm. TDS is a parameter that shows the solid concentration which dissolved in the water. TDS has to be checked every hour to maintain its concentration controlled. In a practical use, TDS monitoring is a simple process but take a lot of time to proceed. Water from the sampling pipe collected in a bottle then cooled until room temperature. TDS from cooled boiler water then measured with a device called TDS meter. To control TDS value in the standard condition, the measurement time need to be reduced. Therefore, a faster method to measure TDS in boiler water is needed. An easier and faster measurement using a system which consisted of sensor, microcontroller, LCD display is one of the idea to reduce unneccessary measuring time. The development and experiment of this TDS monitoring device is situated in Nagasakti Palm Oil Mill, Riau Province, Indonesia.