Ecological Analysis And Optimized Utilization Of Water Resources In Petrochemical Industry

Now, the third structural readjustment has enabled the global petroleum and petrochemical industries that appear industry entralizing, scientific and ecological. The integral level of resource utilization and pollution control of China is lower than that of developed country. Water consumption to refine one ton petroleum in our country is 2.37t/t that is five times than 0.5t/t of developed country. The petrochemical enterprise’s current nameplate capacity includes 1.13Mt/a of refinery throughput, more than 600 kt/a of petrochemical products output, but the enterprise has problems such as resource shortage, environment pollution, etc.The dissertation supported by planned scientific programs of Shanghai Science and Technology Committee (Grant No.042312081) applied industrial ecology concept to petrochemical industry. Ecological analysis in petrochemical industry including ecological chain optimization to enhance productivity and reduce pollution and key technology exploration of energy saving, water saving, consumption and pollution reduction is showing in the dissertation. The main achievement is mentioned as below.(1) Industry and environment problem was analysed systemically in a large petrochemical enterprise. Although primary industry ecological chain is forming, industry and environment problem such as rough production and large resource consumption is in existence. The enterprise should intensify the recovery of the sulfur, organic compound and low quality heat energy from the exhaust gas and optimize the management of the waste residue. Moreover, there is more space in the economy and reusing of the fresh water, and the optimization of the water supply and drainage pipe network is needed urgently.(2) A database for environmental protection management was founded. The database containing almost all the information about the environmental management in petrochemical industry was built with Microsoft Visual Basic.net and Microsoft SQL Server 2000, and the operating interface included main interface, query window, info window and prompt dialog-box.(3) The exhaust gas and waste residue systems were optimized. The exhaust gas of the representative petrochemical enterprise could be reused by limestone/lime-gypsum method, Claus method, adsorption method and thermal combustion method. The remainder heat in the high temperature gas could be recovered with indirect heat exchange method, the waste residue could be recycled with burning-heat recovery method, the waste caustic could be treated with WAO+SBR, and the activator could be revivified with chemical method.(4) A new water system optimization method was built and applied in the representative petrochemical enterprise. The following two research conclusions were obtained:1) A new water system optimization method was advanced and a water system optimization model faced one or more pollution factors was built. The new water system optimization method was based on mass transfer model of water operation, evry operation used circle water and fresh water in turn, and the order is water with limit concentration- other circle water- fresh water. The water system optimization model included hypothesis, object function, terminal condition, pattern function, judgement guideline and operational sequence process chart.2) An optimization programme for single pollution factor and two pollution factors water system was created and applied in practice. The result showed that in water system containing sulfur the fresh water reduction was 38.31% and 19.98% respectively on the conditions of single pollutant and 17.81% on the condition of two pollutants. In water system containing oil, the fresh water reduction was 33.30% and 24.29% respectively on the conditions of single pollutant. What is more, the optimization method had high applicability to conditions such as flowrate change, concentration change, water regeneration and water recycle.(5) Water system was optimized and industry chain was built in the enterprise with new water system optimization method. The following three research conclusions were obtained:1) The method and principle for water recycle were advanced. Effective pproach for water system optimization mainly included condensate recycle, series reuse of wastewater, recycle after deepness treatment, etc.2) Process water system was optimized based on the establishment of water qulity standard and grade. After optimization, the fresh water consumption for desalter, water seal and cooling was reduced from 199.62t/h to11.59 t/h, and 188.03t/h recycle water became the substitute.3) Water system industry chain was built by integrated optimization of the whole water system in the enterprise, the fresh water consumption refining one ton petroleum was reduced from 1.03t/t to 0.53 t/t and the water discharge from 0.53t/t to 0.028 t/t.(6) The secure system for ecology industry was analysed and built. The system mainly consisted of emergency countermeasure for safe production and environment organization management system.