Project SynopsisDevelop preliminary process design information (FEL-1) for an electrical generation unit driven by a municipal solid waste (MSW) pyrolysis system.
PRELIMINARY PROCESS DESIGN BASIS FOR MSW-BASED ELECTRICAL GENERATION UNIT
The client is developing a project to pyrolyze municipal solid waste (MSW) at an existing landfill. The basis of the technology is an externally-heated pyrolyzer developed by the client with no air or oxygen fed to the pyrolysis unit. The client has built and demonstrated a pilot unit to process landfill-bound MSW. The unit has operated batch-wise for several years in development during which time it has processed batches of representative MSW feed and run for short periods at a time.
The purpose of the work executed by Process Engineering Associates, LLC (PROCESS) was to develop a preliminary process design (Phase 1, +/- 30% level preliminary P&IDs) for an MSW-derived-gas to electrical power generation facility. The gas from the client’s pyrolyzer will be cleaned in licensed technology tar removal system and combusted as Product Gas in a packaged boiler. Steam generated in this Product Gas boiler will be expanded in a non-reheat steam turbine generator set. A cooling tower will be used to provide cooling water to condense the steam turbine exhaust. Tar and combustible particulate removed will also be combusted (most likely in a separate tar boiler) in order to generate additional steam and subsequent electrical power.
Specific project tasks performed by PROCESS included:
- Process Design Basis development, which involved the development of the baseline information that governed subsequent process design tasks. Data in design basis included both PROCESS‘ and the tar removal technology providers’ technical boundary limits.
- Mass and Energy Balance preparation, which involved the development of a mass and energy balance for the gas combustion and power generation cycle (Rankine). This included process stream flow rates, compositions, temperatures, pressures, and physical/chemical properties. This involved set-up of a process simulation model in CHEMCAD software.
- Process Flow Diagram (PFD) preparation, which involved utilizing the mass and energy balance information generated during the preceding task and preparing a PFD for the process. The PFD depicted the primary unit operations in PROCESS‘ technical boundary limits.
- Major equipment sizing, which involved the preparation of preliminary (operating conditions and duty) equipment sizing information for the boilers (gas and tar) and steam turbine Rankine cycle.
- Preliminary (+/-30% level) Piping & Instrumentation Diagrams (P&IDs) preparation, which involved utilizing the information gathered and generated previously in developing a PFD for the process. The P&IDs depicted the primary unit operations, process streams, and primary instrumentation and controls.
- Alternative Energy Power Generation
- Preliminary process design
- Process equipment sizing