Objective To demonstrate that an economic energy saving of about 2400 TOE/Y can be achieved in a chemical industry by recovering low temperature heat by an "ORC" group.Description : Sensible heat of light oils from a distrillation column, earlier dissipated, is now recovered in an organic Rankine Cycle (ORC) unit, 1 MWE net output.Innovative aspects : Use of isopentane as working fluid - longterm testing - behaviour of an ORC group within an industrial plant.An Organic Rankine Cycle is used to recover sensible heat from reduced crude and heavy gasoil (HGO) streams in the bottom of an oil refinery crude distillation tower to pre-heat and vaporize isopentane (working fluid). This is expanded isentropically through a turboexpander driving an electrical generator. Expanded isopentane is condensed by means of the refinery cooling water (CW) and pumped back into the loop by means of a centrifugal pump for further heat recovery. Electricity thus generated is to be exported to the National Grid.Several working fluids have been considered but the choice circled on isopentane because : - It was readily available in the refinery, saving on import and storage costs for the initial start-up and routine makeup's.- It had a saturation pressure at prevailing CW temperatures above the atmospheric pressure, thus avoiding complicated sealing arrangements to prevent air inleakage in the system.- It has a reasonable low operating pressure (5 barg), consequently avoiding greater piping and equipment wall thickness.Current refinery throuroughputs are such that it will allow a continuous electrical recovery of at least 1 MW from hot streams at 150 deg. C whose heat content are being dissipated to atmosphere through forced air cooling.The network of shell-tube heat exchangers includes one preheater plus four vaporizers in which shellside are associated in 2 parallel arrangements. They are vertical floating head type with one pass and expansion below.A disengagement drum is required because tubeside thermosyphon contains a liquid with +/- 25 % vaporization.The surge drum will be a cylindrical horizontal drum with a 2:1 ellipsoide heads with a working capacity of 30 m3.The control phylosophy being envisaged is that of maintaining a constant inlet pressure to the turboexpander, but permit the turbine outlet pressure to go as low as possible, depending on the CW temperature. Thus a number of process paameters will vary as temprature of the CW varies-isopentane flow, power output and heat demand. Calculations show however that the impact of the CW temperature change is almost entirely absorbed in the pre-heater. Therefore no significant change will be required either on the long residue or HGO outlet temperature control. Programme(s) ENG-ENDEMO C - Programme (EEC) of demonstration projects and industrial pilot projects (EEC) in the energy field, 1985-1989 Topic(s) 3.4 - INDUSTRY Call for proposal Data not available Funding Scheme DEM - Demonstration contracts Coordinator COMPANHIA PORTUGUESA DE SERVICOS SA (PARTEX) EU contribution No data Address AVENIDA 5 DE OUTUBRO 160 1000 Lisboa Portugal See on map Total cost No data
