R. Lank, D. Tucker
DERP Technologies, L.L.C.,
Keywords: natural gas, turbines, combined heat and power, hybrid power, compressor stalls
Summary:Hybrid Power Supplies that have a natural gas reciprocating engine as its core element of generation and have that engine coupled with a solid oxide fuel cell (SOFC) have the capability of being one of the most efficient means of producing electric conversion possible (according to DOE researchers), but as advances are made in expanding the range of operational parameters, including extreme turn-down, then the greater the stress placed on the generation assets and the greater the likelihood of stalls and of extreme equipment damage under fluctuating load demands. To protect the equipment from mechanical harm and premature wear, the HEP/DG Power Protector with "Blue Button" Valve Controller feature was created and tested under controlled laboratory conditions. It has proven to be an effective and reliable "intervention" that controls flue gases so that the mass flow through the compressor, which is generally kept constant, can be carefully expanded (from 40% to 80%) . This adjustment can be made manually - by the power pant operator -- or it can be automated, using acoustic sensors to detect (and thereby manager) turbine stress. (The sensors would require a high data acquisition system as an ancillary system.) This HEP/DG Power Protector can work with any combination of generation of power sources in a hybrid power system, provided that a gas turbine is at the heart of the configuration. These other complementary generating sources can include fuel cells, concentrated solar, hydro, and even geothermal sources. Since the Hybrid Power Generation power plant can and does serve both civilian and military installations, DERP TECH and its collaborating partner, NETL,had a Poster presentation at the recent Defense Innovation Challenge in Austin, Texas, which was also sponsored by TechConnect. (The attachments were the Poster and the accompanying Flyer from that Conference.) Reduction of fuel (interruption or fluctuation of natural gas supply) can result in a surge cycle, which can have devastating effects on turbine components and can result in loss of power generation. Additionally, the compressor can stall during a dynamic swing in transient conditions; the HEP/DG Power Protector can intervene and keep the compressor's pressure ratio from swinging into the "danger zone." A prototype of the HEP/DG Power Protector is currently functioning at the HyPer Lab at the National Energy Technology Lab (NETL), where it plays a critical and on-going role in preserving the integrity of the on-site hybrid power equipment.