But I like to be surprised, so I took the subway uptown to the 30-story high-rise across the street from Lincoln Center and met two executives from the startup CarbonQuest.CarbonQuest had tapped into the insulated duct that carries hot boiler exhaust to the chimney, diverting the flow through a circuitous array of hissing, humming machinery that pulls out moisture and isolates the carbon dioxide from nitrogen and oxygen, which get released back out the flue.Eventually, a truck pulls up on the street outside, connects a hose to a nozzle on the side of the building, and sucks out the liquid carbon for delivery to a concrete factory, which will inject the greenhouse gas into concrete blocks, making them stronger.“We love that because that was something permanent: We took our exhaust and rendered it inert,” said Josh London, senior vice president in charge of building operations at Glenwood Management, the privately held company that owns the 1930 Broadway apartment building and a couple dozen other rental properties in New York City.While heat-pump vendors figure out solutions for tall buildings, CarbonQuest captures emissions from existing heating systems, paying back the investment by avoiding penalties under New York’s carbon-reduction rules and selling industrial-grade CO2 to paying customers."