CTOTF expands, refocuses services to better serve users

Chairman John Lovelace and the Leadership Commi t tee of the Combustion Turbine Operations Task Force are rapidly moving forward with an ambitious plan to expand and refocus the organization’s services to maximize CTOTF’s benefit to the user community.

Zero liquid discharge. Recall that in July, Lovelace, a consulting engineer for Arizona Public Service Co, Phoenix, announced the formation of a ZLD (zero liquid discharge) Roundtable to help plant managers and staff sort through the wide range of problems surfacing with these systems (montage below). A summary of the group’s first meeting appears later in this article.

Bulletin board and knowledge warehouse. In August, the group launched a custom-designed bulletin board with features that go well beyond those incorporated into its previous interactive site— including a keyword-searchable database of articles, technical papers, and presentations on gas turbines (GTs). The big benefit of CTOTF’s new communications vehicle is that it is available to employees of any company with an equity interest in or currently operating any type of engine— including companies with GTs under construction or on firm order.

Mike Elmo, Goose Creek Systems Inc, Indian Trail, NC, who developed the bulletin board, reports that both user signup activity and site use are growing briskly. To register (users only), complete the short application form at http://forums. ctotf.org/login.asp.

Emergency planning task force. At the group’s Fall Turbine Forum, held in Tempe the last few days of August, Vice Chairman Bob Kirn, manager of technical and production support in TVA’s combustion turbines and distributed resources group, announced the formation of the CTOTFsponsored Combustion Turbine Emergency Planning and Operations Task Force (Ctempo).

The CTOTF leadership sees a need in the GT-based sector of the industry for an active discussion forum, communications network, and database for the consolidation of general information, personnel contact information, and best practices regarding emergency planning, preparation, and operational response.

Goal of Ctempo is to bring together members of the user community actively involved in emergency planning and operations to minimize duplication of effort by sharing best practices, lessons learned, etc. Proactive preparation at the plant level is a primary goal of the task force. Secondarily, Kirn sees the group as a collective industry voice within regional and national emergency-preparation communities. To participate in Ctempo, contact CTOTF Coordinator Wickey Elmo at wickelmo@ctotf.org.

LM6000 User Forum. In October, Lovelace announced that CTOTF’s Aeroderivative Roundtable name had been changed to the LM6000 User Forum to better reflect the focus of the group. KeySpan Energy’s Bill Nawrath was elected chair of the revamped forum, Tom Sparkman of Western Farmers Electric Co-op, Anadarko, Okla, accepted the vice chairmanship. Rich Rebori and Dave Murray of PSEG Power LLC, who had been the chair and vice chair, respectively, of the Aeroderivative Roundtable, were forced to resign as members of the Leadership Committee because of increased job responsibilities.

Nawrath had been Vice Chair of the Generic Roundtable, a position filled by Mike Rutledge of Salt River Project. By way of background, Rutledge is the O&M manager for SRP’s Desert Basin combined-cycle plant in Casa Grande, Ariz; Sparkman is acting plant manager of Western Farmers’ Ana d a r k o Gen – erat ing Stat ion. Ano the r change on the Leadership Committee: Mark Stat ler of Ameren UE, St. Louis, was elected vice chair of the Siemens Roundtable, replacing the timeconstrained Paul Tegen of Cogentrix Energy Inc. Tegen cont inues as chairman of the independent 501F Users Group.

251 Users Group Forum. Most recently, Lovelace announced that the W2 5 1 Users Group had joined the CTOTF family. The group will continue to conduct its focused meetings as a Roundtable within the CTOTF framework, just as the FT8 Users Group Forum has done for years. A summary of the most recent W251 meeting begins on page 160.

Mike Murphy, 1957-2006
The CTOTF membership mourns the passing of Robert M (Mike) Murphy of Puget Sound Energy Inc, Bellevue, Wash. He was past chairman of the Siemens Roundtable and a long-term active participant in CTOTF programs.

Murphy was a Montana native and a graduate of Montana State Univ, joining the utility in 1985. He died in mid September.

Joseph E Mitchell, facility manager of Newark Bay Cogeneration (Newark, NJ) for operator Wood Group Power Operations, will chair the 251 forum. Federico Kitzberger, power generation manager for Argentina’s Capex SA, is the vice chair. Both Mitchell and Kitzberger are members of the CTOTF Leadership Committee.

ZLD challenges

Primary goal of the ZLD Roundtable is to help plant managers and staff sorts through the wide range of problems surfacing with these systems. Many are caused by regulations written without a full understanding of how ZLD works and what its limitations are when hooked up to the back end of powerplant that has to serve the grid reliably and in real time.

Some of the equipment installed in ZLD systems for new GT-based plants is essentially the same as that operating for two decades at several large steam plants in the West, so some practical O&M knowledge exists in the industry and that is helpful. However, recent advancements in membrane technologies and today’s far more demanding regulations regarding the handling of chemicals and of system upsets and liquid discharges have created a cornucopia of new challenges.

ZLD systems certainly are not going away, at least not soon. Because more and more generating units will be required to have them, CTOTF asked Scott Takinen, who manages the West Phoenix Generating Station, and David Brunson, his counterpart at Redhawk Generating Station, to chair and co-chair, respectively, an industry wide roundtable dedicated to helping in the identification and resolution of ZLD issues that could adversely impact plant reliability and availability.

Both facilities, owned and operated by units of Phoenix-based Pinnacle West Capital Corp, are equipped with ZLD systems and the two plant managers are well versed in the challenges these systems present.

The initial meeting of the ZLD Roundtable was the afternoon of Day Three at CTOTF’s Fall Turbine Forum, held the last week of August in Tempe, Ariz. The interest level was high, given an attendee total of 31, which may be a record for a first time user group meeting in this industry. Guest speaker was Devesh Mittal of Aquatech International Corp, Canonsburg, Pa, a ZLD technology leader.

Clearly, ZLD systems have many negatives, including these: (1) restrict the way a power plant is operated, (2) extend the commissioning period, (3) increase cost, project risk, and O&M workload, and (4) require additional manpower and expertise. However, they have one overwhelming positive: Where required by regulation, plants can’t operate without them.

Many attendees spoke of their frustrations in dealing with these systems, scaling in particular. It appears that the industry-wide solutions the GT-based power plant community has come to expect when problems arise on a particular model of gas turbine will not be available for ZLD systems. Reason is that the idiosyncrasies of system design, the physical and chemical characteristics of the waste stream, and site-specific regulatory requirements make for unique conditions at each plant.

Thus the experiences of others generally get you just so far in trouble- shooting problems at your plant. Follow-on time-consuming trial-anderror work often is required to arrive at the solution required.

While many roundtable participants were familiar with parts of what Mittal had to say, his overview of the technologies used to reduce liquid waste streams to solids that can be trucked offsite to a landfill was valuable in its ability to get everyone “on the same page.”

He began with clarification/filtration (lime/soda softening and sludge handling), proceeded through heavy metals removal (ion exchange, reverse osmosis, and chemical precipitation), and oil/water separation before addressing pre-concentration options (Aquatech’s Hero™ membrane process and ultrafiltration plus conventional reverse osmosis), brine concentrators, crystallizers, and sludge dewatering.

A portion of Mittal’s presentation concerned design issues and system evaluation criteria, which were of particular interest to anyone planning to build a plant that would require ZLD. What he achieved was making prospective ZLD users aware of the challenges facing the system designer and the need for far more information than plant owners traditionally have supplied their engineer/constructors—all to minimize operating problems and their severity.

The information ZLD designers need before starting work includes details on makeup water characteristics and pretreatment processes and on cooling-tower operation and cooling- water treatment chemicals, mode of plant operation, etc.

Recognize that a ZLD system must be able to deal with variability in flow rate, which is influenced by dispatch schedule, mode of operation, use of power augmentation steam or not, and ambient conditions impacting cooling-tower operation.

Variability in wastewater quality is another concern. System designers require knowledge of all plant waste streams (continuous and batch), their variability in characteristics, type of organic matter in grey water, cleaning chemicals use in the plant, etc.

To an industry observer, it appears that the challenges facing (1) owner/ operators forced to eliminate liquid discharges, and (2) ZLD system suppliers forced to design to a moving target are reminiscent of the challenges that faced the coal-fired segment of the power industry in the 1970s with respect to SO2 removal. In time, ZLD system design, operation, and maintenance are sure to become easier—if that’s any consolation. ccj