better utilization

Total-site scheduling for better energy utilization [An article from: Journal of Cleaner Production]
$8.95
This digital document is a journal article from Journal of Cleaner Production, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Improving energy efficiency is one of the most important issues for clean production. In a chemical production site, production and utility plants are highly interactive and are all required to perform preventive maintenance to reduce production losses and accidents due to equipment failures. To minimize its impact on production and utility systems during routine maintenance, maintenance scheduling has to be done carefully with consideration of site-wide utilities and material balances. In this paper, a multi-period mixed integer linear programming model, namely a site model, is proposed for generating optimum long-term schedules for plant maintenance as well as production. The model simultaneously takes into account product demands, plant and equipment capacities, site-wide material and utility balances, etc., to optimize a maintenance schedule for a period of two years. The model can be used to maximize site-wide energy efficiency during normal and shut-down maintenance periods, optimise long-term electricity contracts, inventory strategies and purchasing of intermediate materials. A site model contains eight production plants and a utility plant with two boilers and three turbines is used for case studies.

Effective MILP model for oil refinery-wide production planning and better energy utilization [An article from: Journal of Cleaner Production]
$10.95
This digital document is a journal article from Journal of Cleaner Production, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Generally, a refinery complex consists of process system and utility system. Process system not only produces liquefied petroleum gas, gasoline, diesel and so on, but also some byproducts, such as fuel gas and residual fuel oil, which supply utility system as fuel. The utility system converts fuel gas and fuel oil to high pressure or medium pressure steam and electricity to meet the energy demand of the process system. A novel approach to the integration of the process system and utility system for better energy utilization is presented in this paper. A plant-wide multi-period planning mathematical model is proposed and three improvements are identified. First, the process unit energy-consumed model is reformulated, because energy consumed by a unit not only relates the throughput of the unit, but also varies with the operation modes of the unit and season. Second, The MILP (Mixed Integer linear Programming) model of utility system is embedded in the plant-wide model to gain the overall optimization and for better energy efficiency. Third, steam, fuel oil and fuel gas are balanced in the whole plant. Finally, the proposed approach was used in a real industrial example to determine the optimal mass and energy flow and some important results have been obtained and are presented.