Abstract: Sludge is removed from a reboiler while the reboiler is supplying heat to a fractionator, by using sludge removal apparatus added to the reboiler. The reboiler to which the sludge removal apparatus is added comprises an evaporative type shell and tube heat exchanger in which sludge can accumulate as a residue from evaporated liquid, and further in which unevaporated liquid is withdrawn from the reboiler as a product. Sludge removal is accomplished by drawing a relatively small liquid flush stream from the reboiler liquid product stream, pressuring the flush stream through a pump, and then recycling the flush stream to a sparger appropriately disposed in the heat exchanger shell. Sludge dislodged by the sparger is removed along with the reboiler liquid product in a flow path along the bottom surface of the shell through cut-outs provided in the lower edge of the weir and baffle plates in the reboiler which without the cut-outs would block the flow path for the sludge.