Recover Power with Hydraulic Motors

Abstract

Anywhere liquid pressure is reduced across a throttling device, there is a potential application for a hydraulic power recovery motor (HPRM). Cost of power makes HPRM's attractive with recoveries as small as 25 hp on a continuous basis. When incorporated into new plants, expansions, or revamps, payback can occur in as little as six months. When adapted to existing installations, payback may require 12 to 18 months depending on the extent of new hardware necessary. Because it is a positive displacement device, the HPRM torque and speed are almost completely independent - unlike hydraulic power recovery turbines (centrifugal motors). Three screw HPRM's have low moments of inertia, operate at low vibration and noise levels and extract power in the 70-85% efficiency range. Output power levels to 600 hp and differential pressures to 2500 psi are possible. A primary application for the HPRM is driving process pumps. Where a full capacity process pump is used, an HPRM can through-drive it augmenting the primary driver and reducing power requirements by Higher speed special designs also are available 75%.