The technology does exist and many current coal plants are being upgraded with this technology. The two plants I know for sure that are getting the upgrades are in Madison, IN right across the river in Kentucky. These are multi-million dollar upgrades that are creating hundreds of jobs.
My nephew is currently working on such an installation (scrubbers) in the Four Corners region. My guess is that all coal plants will be retrofitted soon, unless our new beloved leader puts them out of business. This technology had been in use for years at the University of Illinois power plant. They were required to burn high sulfer Illinois coal. However, I think they are now mostly using natural gas at a significantly higher cost, but much greater convenience.
The U of I scrubbers produce a lot of gypsum as a byproduct.