Gas Drive

Waste-activated sludge is produced in vast amounts at pulp mills, and is generally sent to be incinerated or landfilled, or can be land applied. Any of these options represented a lost opportunity at the Slave Lake Pulp plant in Alberta. The sludge would instead be repurposed to serve as the main ingredient for anaerobic digestion—a reliable, local, ongoing source of renewable energy.

HH Angus designed a 3 X 3 MWe bio-gas fed cogeneration plant for Slave Lake Pulp, a division of West Fraser Mills. The renewable energy technology integrates energy-efficient anaerobic digestion, using the pulp sludge, into the plant’s existing wastewater treatment system. This allows the plant to generate a methane-rich biogas that produces electricity and heat for the pulping process.

Our scope included: engineering electrical power equipment to integrate from the owner’s 13.8kV switchboard into the electrical generation system distribution to connect the cogeneration equipment; electrical design for a new engineered building housing the cogeneration machines and balance of plant; affiliated balance of plant engine electrical support services, such as high and low temperature cooling, exhaust gas heat exchanger and fresh/waste oil, glycol makeup systems, etc.

HH Angus prepared a 13.8kV single line diagram for the electrical system, from the power generation modules through the switchboards, to the interface to the utility service and existing owner’s distribution system; plus preparation of a 600V & 120/208V single line diagram for the generator, building auxiliary and balance of plant services. We also designed protection and control systems, and connection arrangements including SCADA with AESO.