Obiettivo Condensate from a bauxite digestion process is sometimes contaminated. To protect the boiler the condensate is not reused. In this project conductivity probes will test the condensate and allow clean water to be reused, saving 3500 toe/year.The innovation claimed is the use of a conductivity probe.The project suffered a major setback due to inclusions of 20-25 ppm organics found in the condensate. Fouling of the boiler feedwater pre-heaters (which utilized regenerative steam) reduced the energy saving impact of the scheme to such an extent that the project is not viable until the problem is resolved. Tests have shown that a possible remedy may be filtration using a combination of ion exchange and activated carbon. A pilot plant is presently being installed to confirm process feasibility, the results of which should be available by the end of the year 1991.The process will recover the heat of the condensate from contaminated Bauxite steam flash pots and feed the condensate directly to the feed-water of the de-aerator serving 3-watertube boilers. The condensate is available across 9 vessels from 219 deg to 112 deg, however, much of this condensate at the low pressure end is contaminated. Only 5 out of the 9 vessels have good quality water.The system proposed will collect the condensate from two vessels (No's 3 & 4) using a single flash pot at 110 deg. The collected condensate will then be pumped onto a header to increase the boiler feed water from 90 deg to 103 deg.The additional benefit of the scheme is that by returning the condensate to the boilerhouse, the use of treated water decreases by more than 50 %. As a consequence less steam is required for low pressure boiler feed water heating.With this surplus steam available, the flash steam from flash tanks nr 5 and 6, with jumper lines installed, can be fed to the flow pressure steam system.The total energy savings for both the condensate and low pressure steam recovery systems are as follows :- 2,520 tonnes oil + 1,529 tonnes oil= 4,049 tonnes oil.As a result of the recovery system there will be an increase in the boiler blowdown rate. This is equivalent to 485 tonnes of oil.Therefore, nett saving is 3,564 tonnes of oil. The control system will have 12 detection and metering points. The system will be flow controlled for an initial blend of 160 m3/hr of condensate with approximately 130 m3/hr of treated water. A flow meter will record the flow which in turn, will be controlled by an air actuated valve. The quality of the condensate will be monitored by duplicate conductivity meters at the inlet of the flash pot. In the event that the condensate exceeds a pre-set target, this conductivity meter will close the automatic shut-off valve and trip the on-line pump. As a result, the existing level control system will adjust by increasing the demand for treated water and pump it through the present routing. Programma(i) ENG-ENDEMO C - Programme (EEC) of demonstration projects and industrial pilot projects (EEC) in the energy field, 1985-1989 Argomento(i) 3.4 - INDUSTRY Invito a presentare proposte Data not available Meccanismo di finanziamento DEM - Demonstration contracts Coordinatore AUGHINISH ALUMINA LTD Contributo UE Nessun dato Indirizzo Aughinish Island, Askeaton CO LIMERICK Irlanda Mostra sulla mappa Costo totale Nessun dato
