Landfill Energy Systems

Landfill Energy SystemsThe Project

The Utilization of Landfill Gas to produce Renewable Energy has been on a rise in the past years. DTE Energy has hired McKenna Engineering to provide a complete “Turn Key” landfill energy system package for the Uwharrie Landfill in North Carolina. McKenna Engineering has built an LFG Booster Blower Package to gather gas from extraction wells, boost gas pressure to 6.5PSIG, to then cool and dry the gas that will be collected and delivered to six reciprocating engines for electricity.

The Purpose

The gas collection system is provided with an Inlet separating vessel with a demister (stainless mesh) to separate water droplets from landfill gas. The separator is provided with a manual drain and an automatic drain controlled by a level transmitter. The Landfill gas then travels through a multistage centrifugal blower which boosts the pressure from a slight vacuum to 6.5PSIG. In doing so, the heat of compression heats the gas to 230 Degrees F. We then have a fin fan heat exchanger to cool the gas down to 15 degrees above the ambient temperature. The concern at this point is the amount of water vapor that will be condensing in the gas stream.

The Solution

LACT unitsTo solve this problem, we have installed a dehydration system that will chill the landfill gas down to 45 Degrees F, remove the condensate, then reheat the gas back up to 90 degrees F. This drops the relative humidity in the process gas allowing clean dry gas to be delivered to the engines for combustion. The system will be delivered completely pre-piped, pre-wired to a complete starter/control panel (all VFD’s & PLC), and pre-tested (full mechanical run test at McKenna Engineering’s facility in Carson, CA) ready for installation at the jobsite. The “Turn Key” approach allows the customer to place the energy system package on the foundation, connect the inlet and discharge piping, put power to the panel, and press start.

Major Equipment

Complete Starter/Control Panel (200HP VFD & PLC), 200HP Gardner Denver Multistage Centrifugal Blower, Fin Fan Heat Exchanger, Gas Dehydration Unit, Gas Analyzer, Inlet Separator, a Bypass Control Valve and an 80 Ton Chiller