Preoperational Cleaning Requirements for HRSG Units

Author(s):  
Robert D. Bartholomew ◽  
Emory H. Hull

There have been no generally agreed upon practices regarding preoperational chemical cleaning of new heat recovery steam generators (HRSGs). Some have been cleaned only with warm detergent solutions while others are cleaned using alkaline detergents followed by iron oxide removal and passivation stages. Thorough inspection and monitoring of waterside surfaces from fabrication through commissioning are necessary to assess unit cleanliness. However, these activities are sometimes neglected. In some cases, there is no contingency plan should inspection reveal fouled or corroded surfaces. Poor waterside cleanliness has caused startup delays and problems during subsequent operation. This paper summarizes the recommended requirements for both companies that plan to clean and for those companies that do not expect to clean.

Author(s):  
W. V. Hambleton

This paper represents a study of the overall problems encountered in large gas turbine exhaust heat recovery systems. A number of specific installations are described, including systems recovering heat in other than the conventional form of steam generation.


Author(s):  
Akber Pasha

In recent years the combined cycle has become a very attractive power plant arrangement because of its high cycle efficiency, short order-to-on-line time and flexibility in the sizing when compared to conventional steam power plants. However, optimization of the cycle and selection of combined cycle equipment has become more complex because the three major components, Gas Turbine, Heat Recovery Steam Generator and Steam Turbine, are often designed and built by different manufacturers. Heat Recovery Steam Generators are classified into two major categories — 1) Natural Circulation and 2) Forced Circulation. Both circulation designs have certain advantages, disadvantages and limitations. This paper analyzes various factors including; availability, start-up, gas turbine exhaust conditions, reliability, space requirements, etc., which are affected by the type of circulation and which in turn affect the design, price and performance of the Heat Recovery Steam Generator. Modern trends around the world are discussed and conclusions are drawn as to the best type of circulation for a Heat Recovery Steam Generator for combined cycle application.


2021 ◽  
Vol 68 (6) ◽  
pp. 452-460
Author(s):  
P. A. Berezinets ◽  
G. E. Tereshina

2021 ◽  
Vol 68 (2) ◽  
pp. 110-116
Author(s):  
M. A. Vertkin ◽  
S. P. Kolpakov ◽  
V. E. Mikhailov ◽  
Yu. G. Sukhorukov ◽  
L. A. Khomenok

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001726-001742
Author(s):  
Alan Huffman ◽  
Jason Reed ◽  
Matthew Lueck ◽  
Christopher Gregory ◽  
Dorota Temple ◽  
...  

The study of copper-based bump structures for interconnects in 3D integration applications has been ongoing for several years. Typically, an array of Cu bumps is bonded to an array of Sn-capped Cu bumps or another Cu bump array using a thermocompression bonding process. These processes rely on high pressures and temperatures to facilitate bonding between the bump arrays. In order for this bonding to take place, some method of oxide removal is normally required for the Cu and/or Cu/Sn bump surfaces before bonding. A number of different methods have been investigated by a number of groups, including chemical cleaning, plasma cleaning, self-assembled monolayers, and no-flow underfill (NUF) materials. The use of NUFs is particularly intriguing, since these materials can be formulated with fluxing agents which could reduce surface oxides on Cu and Sn and can be deposited immediately prior to the thermocompression bonding process. In addition, the material provides a protective encapsulant to the interconnect array, protecting it from environmental damage and adding mechanical strength to the assembly. We will present the results of a study to evaluate new fluxing NUF materials in thermocompression bonding processes on full area array test devices with 25 micron bump pitch. The test devices are fabricated with either Cu or Cu/Sn bumps to provide two different bonding options (Cu to Cu or Cu/Sn to Cu). We will compare the NUF bonding process and resulting bonded interfaces to assemblies fabricated using our standard bonding processes, which rely on both chemical and plasma pretreatment processes to prepare the bump arrays before bonding. Mechanical and electrical data will be used to compare the two bonding processes, as well as SEM cross-section analysis of the bonded interfaces.


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