Owner - MWRDGC
Client - Ameresco
Location - Chicago, IL
The Digester Gas Utilization Facilities, at the Calumet Water Reclamation Plant (CWRP) will enable the District to treat biogas generated from their current digestion process along with future digestion of a high-strength organic waste stream (currently under design by the District). The digester gas from these two sources will be treated at the CWRP to a level of quality acceptable for injection into a natural gas pipeline, through the new High BTU plant.
The High Btu Plant will include biogas compression, metering, and filtration via a pressure swing adsorption sieve which removes moisture and contaminants to acceptable levels as required by the natural gas pipeline company. The resulting commercial quality gas will be injected into a natural gas pipeline. All gas production equipment will be skid mounted and located outdoors near the Gas Flare and Boiler Building. The low voltage electrical equipment that will power this equipment will be located in the mezzanine level of the Boiler Building. A new electrical service will be fed from the Pump and Blower Building 13.2 kV switchgear to a new 2000 KVA transformer located near the Boiler Building. The transformer will have a primary disconnect and the secondary side shall feed a new Motor Control Center (MCC) located in the Boiler Buildings mezzanine level. The MCC will then feed a stand-alone 600HP VFD, two 250HP and one 150HP soft starters as well as approximately 10 stand-alone VFD’s of 100HP (UC) or less. There will be a conduit bridge to bring the conduits from the mezzanine level out to the skid mounted equipment above grade. The skid mounted equipment is classified as NEMA 7 equipment with a 10 foot envelope, therefore any potential arc inducing equipment will either be Class 1 Division 1, and Class 1 Division 2, or located outside the classified envelope. The BTU plant will be controlled by individual PLC’s located on each individual skid. There will be a master controller for the High BTU system located in the boiler building control room. A communication link will be set up from the master controller for the new High BTU plant back to the existing plant DCS system. This link will transmit all status and alarm information, but will not be used for control.