Tucson Electric Power values clean technology and additional revenue

Located in Tucson, Arizona, the Sundt RICE power plant consists of 10 natural-gas-fired reciprocating internal combustion engines (RICE). Plant owner Tucson Electric Power (TEP) is able to take advantage of increased energy efficiency thanks to an investment in two Alfa Laval Aalborg heat recovery steam generators (HRSG). By utilizing excess exhaust gas heat to produce steam, TEP has gained both an additional revenue stream and an improved environmental profile.

DATE 2022-02-03

Sundt RICE is situated near a process plant that specializes in asphalt storage, an application that creates a great demand for steam. Seeing potential to provide advantages for both plants, TEP took this into account during the engineering phase of the Sundt RICE facility. Working with their engine supplier Wärtsilä North America, Inc., they started a search for the optimal method of recovering the plant’s excess heat.

The choice of technology was not initially obvious, as heat recovery steam generation after RICE is not a traditionally well-known application in the United States. However, Wärtsilä was able to advise TEP based on more than three decades of experience with Alfa Laval Aalborg technology. This, together with a proven record of success in heat recovery and experience in combined cycle and combined heat and power, convinced TEP that Alfa Laval was the right supplier for their needs.

TEP ultimately ordered two Alfa Laval Aalborg AV-6N HSRG units for the Sundt RICE plant. In the negotiation process, they raised a concern that the long transition line may impact steam dryness on their customer’s end. Alfa Laval therefore advised them to add a superheater circuit in the HRSG, ensuring maximum steam quality. The result has been a solution that fully meets all of TEP’s needs.

Alfa Laval Aalborg’s HRSG system and its performance at our power plant are impressive. The high-efficiency system exceeds our expectations, generating continuous additional revenue.
Conrad Spencer, Director Sundt Generation Modernization Project at TEP

Clear economic as well as environmental benefits

The added revenue that Spencer notes is really just the start. With steam generation utilizing hot exhaust gas, the Sundt RICE facility boosts the energy efficiency and reduces the total emissions of the plant.

Alfa Laval guaranteed total values of 32,716 lbs/h (14,840 kg/h) superheated net steam at 408°F (209°C) /175 psig (12.1 barg) for both units at the Sundt RICE plant. During the performance test, however, these values were actually exceeded.

If the same amount of steam had been produced through a natural-gas-fired unit, it would require over 388,000 MMBtu of natural gas in full operation throughout the year. This would result in over 22,000 metric tons of CO2 emissions – equivalent to what 1400 US citizens produce annually. This shows the savings potential of the HSRGs.

Moreover, after the initial investment, operation of the Aalborg AV-6N equipment entails no significant operational or maintenance costs. Utilizing the heat from the RICE is also practically free of charge, while the tailor-made and automated control system maximizes unmanned operation time.

A tailored scope

The steam generation system supplied to TEP includes two natural-circulation HRSGs and auxiliary equipment, designed, manufactured and registered according to ASME Section I Rules for construction of power boilers. Alfa Laval’s overall scope on this project included detailed engineering, thermal and system design, as well as commissioning and end-user training.

“It has been a pleasure to work with Alfa Laval’s experts in waste heat recovery on this project – from initial engineering to commissioning and training,” concludes Spencer.

Sundt RICE power plant steam generation system.

About the Aalborg AV-6N

AV-6N waste heat recovery boiler

The Alfa Laval Aalborg AV-6N is a robust, highly efficient heat recovery steam generator that improves a plant’s total efficiency.

With the Aalborg AV-6N, waste heat from flue gas is recovered from sources such as industrial processes, diesel and gas engines or gas turbines, in order to generate steam and/or heated water. The solution ensures flexible operation and is easy to install – even at existing facilities.

More about AV-6N

Fast facts

The customer
Tucson Electric Power (TEP) owns and operates the 182 MW Sundt RICE power plant in Arizona, USA. The plant has 10 Wärtsilä natural-gas-fired reciprocating internal combustion engines.

The challenge
To recover excess heat from exhaust gas to generate steam for a neighbouring process plant.

The solution
Two Alfa Laval Aalborg AV-6N heat recovery steam generators (HRSG), along with associated auxiliary equipment.

The benefits
Profit from generated steam, increased energy efficiency and a positive environmental impact.

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