Searles Valley Minerals Operations Inc. (SVM) SVM built a condensate recovery and delivery system at the is located in the California high desert near the Westend plant and a condensate receiving system at the Argus town of Trona. The company mines minerals out plant. These systems include instrumentation for monitoring and of the Searles dry lake named for its founder, John controlling water quality and chemical treatment for corrosion Searles, who discovered the minerals more than 130 control. Vertical pumps return condensate the entire distance from years ago. At the site, SVM operates three mineral the Westend condensate collection receiver to the Argus condensate processing plants, two power plants and a mining receiver. Foxboro DCIS systems in the plants provide monitoring operation to manufacture soda ash, borate and sodium sulfate. and system control for all facets of the project.
One of the power plants, known as Westend, was originally a gas- About 150 kpph of steam is supplied from the 450 psig header firedplantthatincludeda45-year-old GEFrame5turbinegenerator at the Argus plant at around 430 psig and 620 F. The steam is and heat recovery steam generator (HRSG) that produced 16 M W transported via a 12-inch insulated carbon steel line to the Westend of electricity and 100 kilopounds per hour (kpph) of 250 psig plant at about 270 psig and 500 F. There it connects to a pressure steam. It also included a gas-fired control valve, which maintains the packaged boiler that produced up Westend plant main steam header to 60 kpph of 250 psig steam. The at 250 psig. A six-inch insulated second power plant, named Argus, carbon steel line returns steam is a coal-fired plant that includes two condensate to the Argus plant’s 30-year-old, 700 kpph, 1,500 psig coal-fired boilers.
Combustion Engineering VU40 Although replacement steam for steam generators and two 27. 5 Westend is supplied from Argus coal MW GE medium pressure steam boilers, no additional coal burning turbines. SVM operates both plants, was required. Several conservation which provide baseload electricity for projects were completed in parallel its mineral mining and processing with the steam line construction operations. ensuring that enough steam In 2007, SVM began a project to would be available to Westend. shut down the gas-firedpower and “The idea is to use the steam steam production at its Westend conservation project so that no plant and provide coal-fired steam generating capacity is lost,” Buchs from its Argus plant. The project, said. “Reduced consumption was which earned a $3.6 million the target and it is being achieved. incentive rebate from Pacific Gas & Electric Co., was the largest There is a smaller amount of gas used in the mineral plant processes natural gas savings project awarded in the rebate program’s history, which will continue to be used.” said Roland Buchs, SVM’s director of utilities and engineering. “By The project included installing a thermo-compressor and shutting down gas-fired steam and power generating equipment 90-pound flash system on rotary steam dryers at Argus. The at the Westend plant, the project saves about 4,500,000 therms of thermo-compressors optimize 450 psig steam usage to the rotary natural gas each year,” he said. dryers The 90-pound system flashes the high-pressure condensate
The distance between the two plants is a little more than four from the dryers. This replaces 450 psig steam that had been used miles. The pipeline SVM installed to transfer the steam, however, is to heat two fluid bed dryers. In addition, a new heat exchanger just over five miles long, the result of routing and expansion loops. preheats feed brine from the lake injection mining operation, using A steam supply line and a condensate return line run parallel to each the warmer’s spent brine that is returned to the lake rather than other across the dry floor of Searles Lake. These lines stand a few steam.
feet above ground level with the help of steel pipe supports. The A third conservation project currently in progress will cool the vertical expansion loops also serve as crossing locations for roads gases being compressed by a series of steam-driven compressors that occasionally cut across the pipeline. Bridges are used where so that the volume of compressed gas is reduced, resulting in less the pipe crosses railroad tracks, and a single underground crossing steam to drive the compressors. accommodates a county highway. Altogether, there are more than The project required no reviews or revisions to the Argus 60 steam pipe loops in the system. There is also one condensate pipe plant’s environmental New Source Review status. SVM was vertical expansion loop for every two steam pipe expansion loops. required, however, to obtain a review of issues involving pipeline
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