FRAC SAND PLANT
Krech Ojard & Associates was retained for engineering services for the design and construction of a new frac sand plant. Krech Ojard performed services from the preparation of preliminary flow sheets through final construction documents and project management for this 2.6 million tons per year frac sand processing facility.
Upon completion of flow sheets, Krech Ojard began design of the frac sand plant layout and process. Our Mechanical, Structural, and Electrical Groups worked together to ensure that interferences were minimized. Design components for the plant included:
- Plant Layout
- Foundation and Structural Steel Design
- Conveyors and Elevators
- Material Handling Equipment
- Sand Processing Equipment
- Piping
- Rail and Truck Dumps
- Raw and Processed Sand Storage
- Electrical Power
- Control Systems
The KOA Electrical Group engineered much of the electrical system for the facility including:
- 25kV electrical power system
The medium voltage electrical power system at the Chippewa Falls frac sand plant consists of a 25kV, 600A, outdoor main and distribution switchgear lineup, one single-ended outdoor substation and two double-ended indoor substations. The single-ended substation is comprised of a 1500kVA transformer with secondary-side main breaker and distribution feeder breaker sections. Each double-ended substation is comprised of two 2500kVA transformers with secondary-side main breaker, distribution feeder breaker and tie breaker sections. The KOA electrical engineering group designed the 25kV electrical power system. The electrical engineering included 25kV outdoor substation design and layout, equipment specification and proposal review/approval, surge protection specification, underground electrical ductbank design and layout, cable sizing and routing based on ductbank cable heating calculations, and design and development of electrical installation construction drawings.
- Power distribution
The low voltage power distribution system at the Chippewa Falls frac sand plant is a 480V system consisting of main electrical rooms in the Wet/Dry Plant and switchgear lineups at nine other major electrical load areas on the site. Electrical rooms in the Wet/Dry Plant include an indoor substation switchgear room on the first floor and a large MCC room on the second floor. Site-located switchgear lineups each consist of a main breaker section and physically separated distribution feeder breaker sections. The main and distribution sections were separated to minimize arc flash hazard clothing requirements. The KOA electrical engineering group designed the low voltage power distribution system. The electrical engineering included modeling the system with SKM Power ToolsR software, conductor sizing and routing, circuit breaker selection and setting, and cable tray system design and layout. Conductor sizing and routing included, cable specification, load flow calculations, voltage drop calculations, and cable schedule tabulation. Cable tray system design included cable tray specification, cable tray schedule tabulation, and development of plan-view cable tray layout drawings.
- Facility grounding
The facility grounding was designed to meet Mining Safety and Health Administration (MSHA) requirements. Structures and equipment were examined and accounted for in the creation of an equi-potential ground-grid. The complete facility is tied together in one continuous grid as required by the National Electrical Code (NEC). Facility grounding provisions include; ground test wells, transformer grounding grids, building perimeter grounding, concrete encased electrodes as permitted, and boring for burial of ground rods to achieve a low enough ground resistance to meet MSHA codes. Motor Control Center (MCC) rooms were provided with continuous perimeter grounding for accessibility and ease of panel equipment grounding.
- MCCs for the facility
MCC installations at the Chippewa Falls frac sand plant consist of twenty separate MCC lineups, twelve in the Wet/Dry Plant MCC room and eight at other major electrical load areas on the site. The KOA Electrical Group design of the MCC installations included equipment specification and proposal review/approval, MCC room design and layout to NEC clearance requirements, MCC one-line diagram drawing development, MCC front elevation drawing development, and motor elementary diagram design and drawing development.
- Controls
The controls system consists of an Allen Bradley Control Logix platform with a central rack containing a processor, and many remote control panels, each with their own remote Control Logix rack. Communications between the main PLC and the remote racks was accomplished via fiber optic Control Net to each individual rack as needed. The MCC’s are communicated via Control Net and Device Net.
- Related Services
Additionally structural requirements for electrical equipment system loads imposed on structures and soil were designed by KOA Structural Group personnel to insure continued proper operation through the projects life cycle. Selected working points and elevations were determined by the KOA Civil group.
The Chippewa Falls frac sand plant was a fast track design-build method of delivery requiring close coordination between the owner, contractor and Krech Ojard.
