Table of Contents

A fter four months of effort, nothing was working,” said Tom Ziegler, AmerenUE performance engineer, referring to the time 13 years ago when AmerenUE first tried neural network-based combustion optimization technology at its Labadie plant to help reduce its nitrogen oxide (NOX) emissions. “But instead of cutting our losses, we kept trying.” Two years later, Labadie had one of the lowest NO_X emissions rates in the nation among coal-fired plants with no selective catalytric reduction (SCR) systems. The then-novel combination of combustion optimization software, low-NOX burners (LNB), over-fire air (OFA) and in-house expertise was the key reason.

The relative ease of manufacturing and erecting a combined cycle power plant (CCPP) and the considerable shortening of time required to achieve commercial operation has made the CCPP the plant of choice for utilities as well as independent power producers. This popularity has led to many innovations for increasing the power output and the efficiency. Of the three main components of the CCPP—gas turbine (GT), heat recovery steam generator (HRSG) and steam turbine (ST)—the GT has gone through numerous innovations and improvements. The ST traditionally has the capacity to accept higher amounts of steam at higher pressures, so very little improvements to the ST were needed. However, the HRSG, which is sandwiched between the GT and ST, has to undergo many changes due to the impact of higher amounts of gas at higher temperatures from the GT and the requirement of higher-pressure steam at a higher temperature to boost the ST efficiency.

The increasing demand for circulating fluidized bed (CFB) boilers to co-fire biomass and waste fuel products creates increased stress on refractory systems resulting in more frequent replacement cycles and increased maintenance costs.  The problems with refractory systems in this application are accentuated due to improper application and/or inappropriate material selection.

The U.S. Environmental Protection Agency (EPA) has awarded “ENERGY STAR” recognition to four high quality combined heat and power plants around the country as part of its CHP Partnership operations. The CHP Partnership is a voluntary program seeking to reduce the environmental impact of power generation by promoting the use of CHP. It works with energy users, the CHP industry, state and local governments and other clean energy stakeholders to facilitate the development of new projects and to promote their environmental and economic benefits.

Temperature control is a big deal in Pittsburg, Texas, where summer afternoons average in the mid-90s and frequently top 100. At AEP/SWEPCO’s J. Robert Welsh Power Plant, however, the problem didn’t lie in the outside temperature, but in controlling the reheat temperature. The pneumatic actuators on the attemperator valves couldn’t smoothly control the valves at low levels, slamming back and forth between 10 percent open and fully closed.

As the power industry makes the shift from analog to digital control systems, power utilities are redesigning their control rooms to accommodate the digital control upgrades.

There are numerous coal energy conversion project feasibility studies performed under contract with the U.S. Department of Energy’s National Energy Technology Laboratory (NETL) which include capital cost estimates. The estimates are developed by engineering firms that often use “installation factors” which multiply the price of the equipment to yield the total installed cost. The best known installation factors were created by Lang in 1947 and Hand in the 1960s. Although these types of factors have been updated for escalation, they have not been adjusted to reflect the current practice of building “dressed equipment.”

Many power plants and other industrial facilities utilize open recirculating cooling systems equipped with cooling towers for heat transfer from condensers and other heat exchangers. Cooling towers commonly sit well away from the main plant, and it is often possible to forget about them until something goes awry. This article outlines the fundamentals of heat transfer in a cooling tower and important issues for maximizing heat exchange.

In the mid-1980s the power industry experienced high energy piping (HEP) system failures that resulted in personnel injuries and fatalities, as well as damaged equipment and loss of power generation. Power industry leaders worked together with the Electric Power Research Institute (EPRI) and the Materials Property Council (MPC) to study HEP failures, to understand the causes and to develop resources for avoiding future failures.