A Simple Strategy for Optimal Operation of Heat Exchanger Networks
نویسندگان
چکیده
The objective of this work is to propose a systematic procedure to find a control structure for optimal operation of heat exchanger networks. Optimal operation in this context requires that 1) all controlled temperatures are kept at their targets and 2) utility cost is minimized. The degrees of freedom of heat exchanger networks are analyzed and used to identify if the operation is structurally feasible and if the utility cost can be optimized. The LP problem formulation for optimal operation of HENs implies that optimal operation is always at active constraints in terms of target temperatures and zero or maximum heat transfer (such as fully open or fully closed bypass valves). The information from an offline optimization is used to identify the set of nominally active constraints, and then split-range and selective controls are used to track the active constraints during operation for optimality.
منابع مشابه
Control structure design for optimal operation of heat exchanger networks
When only single bypasses and utility duties are used as manipulations, optimal operation of heat exchanger networks (HENs) can be categorized as an active constraint control problem. This work suggests a simple split-range control scheme to implement the optimal operation. The control structure can be found by solving an integer-linear programming (ILP) problem with two objective functions pro...
متن کاملOptimal operation of heat exchanger networks with stream split: Only temperature measurements are required
For heat exchanger networks with stream splits, we present a simple way of controlling the split ratio. We introduce the “Jäschke Temperature”, which for a branch with one exchanger is defined as TJ = (T − T0)/(Th − T0), where T0 and T are the inlet and outlet temperatures of the split stream (usually cold), and Th is the inlet temperature of the other stream (usually hot). Assuming the heat tr...
متن کاملA Simple Control Scheme for Near-optimal Operation of Parallel Heat Exchanger Systems
For heat exchanger networks with stream splits, we present a simple way of controlling the split ratio. We introduce the ”Jäschke Temperature”, which for a branch with one exchanger is defined as TJ = (T−T0) Th−T0 , where T0 and T are the inlet and outlet temperatures of the split stream (usually cold), and Th is the inlet temperature of the other stream (usually hot). Assuming the heat transfe...
متن کاملArea Energy and Throughput Targeting in Debottlenecking of Heat Exchanger Networks with Decomposition Approach
For energy saving retrofit projects, its economics are usually evaluated in terms of capital investment and payback time. The capital investment is in direct relation to the total heat recovery area of the network and the payback time factor is base on both the area and the energy savings. The debottlenecking is an increased throughput, which can be profitable in economic sense. The combination...
متن کاملOptimal operation of heat exchanger networks
The paper discusses optimal operation of a general heat exchanger network with given structure, heat exchanger areas and stream data including predefined disturbances. A formulation of the steady state optimization problem is developed, which is easily adapted to any heat exchanger network. Using this model periodically for optimization, the operating conditions that minimize utility cost are f...
متن کامل