Study On The Application Of Process Energy Integration In The Energy Optimization Of Heat Combinated Refinery Unit

As a greatest developing nation, China is not only one of the big countries of energy-production but also a consumption one, the production of energy source is in the third rank in the world, and the consumption second; petroleum import dependency raised to 33.8% in 2000 from 7.6% in 1995. The proportion of energy consumption expenditure of GDP reaches 13.5%, in which the largest industries such as petrochemical, metallurgy, construction etc occupies above half of the total energy consumption. Obviously, the sustainable development has become China's new strategy replacing traditional economical model. So from now, we should focus on the energy -using and energy -saving. Using the method of process energy integration and guiding with process thermodynamics, this paper has systemically studied the energy optimization of heat unite among oil processing units in refinery from the view point of system engineering, and established the research method for units'heat unite based on selecting the temperature of as system optimizing variable. This paper has propounded internal adjustment measures for united units to ensure energy-using optimization, which includes flexibility analysis and synthesis of heat-exchange network, as well as operation optimizing for fractionating tower system under new boundary conditions, also involves available energy economic adjustment optimizing strategy of whole system based on local optimization in units. Heat unite energy optimization has been successfully applied in delayed coking and hydro-refining units using light coke gas oil as direct-stock, which shows the methods above is feasible. We have gotten achievements as follows: 1. Put forward the energy optimizing method for units'heat unite with the temperature of direct-stock as system variable; 2. Establish system heat-exchange network among units under the temperature of original direct-stock, determine the flexibility analysis and synthesis method, and compile the correlative software; 3. Discuss the application thoroughly in system heat-exchange network and trouble-shooting strategies of relative technology problems for "ICI pinch design theory"and "three-link energy flow structure model"; 4. Constitute the local energy optimization strategy in the large units'system as well as relative energy optimization model and analysis method of available energy economics. 5. Set up the system adjustment optimizing schemes for relative process parameters aroused from units'heat unite, together with the technology optimizing implementation ones for fractionating tower under new boundary conditions; 6. Apply the heat unite energy optimizing scheme in delayed coking and hydro-refining units directly fed with gas oil, which cost-effectively solved a serious of theoretic and practical problems in the heat-exchange network design for heat unite units.