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Zheng X.,University of Manchester | Zheng X.,Process Integration Ltd | Kim J.-K.,Hanyang University
Industrial and Engineering Chemistry Research | Year: 2011

A systematic methodology for the synthesis of power systems has been developed, which explores the interactions among the equipment as well as the processes in power and utility systems. Also, the optimization is able to study the integration of CO 2 capture processes with power systems for minimizing site-wide fuel consumption. Typical operating conditions for precombustion as well as postcombustion CO 2 capture have been applied to estimate energy demand within the CO 2 capture process. The power system is designed not only to meet the electricity and shaft power demand from the background process but also to satisfy the additional energy requirement incurred by CO 2 removal. With the energy integration for the overall systems, the fuel consumption could be reduced, and operating cost, minimized. A case study is presented to demonstrate the usefulness and effectiveness of the proposed methodology for the design of energy and power systems in liquid natural gas (LNG) plants, under a carbon-constrained business environment. © 2011 American Chemical Society. Source

Ahmad M.I.,University of Peshawar | Zhang N.,University of Manchester | Jobson M.,University of Manchester | Chen L.,Process Integration Ltd
Chemical Engineering Research and Design | Year: 2012

Heat exchanger networks are an integral part of chemical processes as they recover available heat and reduce utility consumption, thereby improving the overall economics of an industrial plant. This paper focuses on heat exchanger network design for multi-period operation wherein the operating conditions of a process may vary with time. A typical example is the hydrotreating process in petroleum refineries where the operators increase reactor temperature to compensate for catalyst deactivation. Superstructure based multi-period models for heat exchanger network design have been proposed previously employing deterministic optimisation algorithms, e.g. (Aaltola, 2002; Verheyen and Zhang, 2006). Stochastic optimisation algorithms have also been applied for the design of flexible heat exchanger networks recently (Ma et al., 2007, 2008). The present work develops an optimisation approach using simulated annealing for design of heat exchanger networks for multi-period operation. A comparison of the new optimisation approach with previous deterministic optimisation based design approaches is presented to illustrate the utilisation of simulated annealing in design of optimal heat exchanger network configurations for multi-period operation. © 2012 The Institution of Chemical Engineers. Source

Hirata K.,Mitsubishi Group | Hirata K.,Process Integration Ltd | Kakiuchi H.,AQSOA Gr.
Applied Thermal Engineering | Year: 2011

The Ethylene production plant is one of the most important plants in the petrochemical industry. The process requires a huge amount of low temperature cooling but at the same time it discharges a large amount of low temperature heat. This low temperature heat source can be utilized to run an Adsorption Heat Pump (AHP) for chilled water (ChW) generation, or for direct process cooling. In this paper, a process integration study is performed that applies an AHP to partially replace some of the cooling loads in the propylene refrigeration system that is a part of the cooling system in an ethylene process. This integration successfully reduces the overall compressor power of the propylene refrigerator by 10%. Other potential benefits are also reported, along with the capital investment and pay back time of the heat integration project. The potential modifications identified in this study include utilizing the chilled water (ChW) generated by AHP for both the depropanizer condenser and the charge gas chiller at the 5th stage of the charge gas compressor (CGC). If the modification of the depropanizer condenser was applied to all the ethylene plants around the world, a reduction in emissions of 4.6 Mt of CO2 could be made each year. © 2011 Elsevier Ltd. All rights reserved. Source

Hirata K.,Mitsubishi Group | Hirata K.,Process Integration Ltd
Chemical Engineering Transactions | Year: 2011

Ethylene production plant is one of the most important plants in petrochemical industry. The process requires a huge amount of low temperature cooling, so highly process integrated configurations created by applying PI (Process Integration) technology to the process was included in advanced processes. The process analysis for the advanced process was likely important for creating further new process configurations on energy saving. Accordingly, how contributed PI technology to creating a new process configuration was described here. The new network was Heat Integration between Deetanizer condenser and C2 splitter side stream liquid flow from the tray at stripping section. The energy saving benefit was 102 MUS$/y, CO2 emission reduction was 7,360 t CO2/y, and payback time was 1.42 y. Copyright © 2011, AIDIC Servizi S.r.l. Source

Lin Z.,Process Integration Ltd | Zheng Z.,Process Integration Ltd | Smith R.,University of Manchester | Yin Q.,Process Integration Ltd
Theoretical Foundations of Chemical Engineering | Year: 2012

The reliability of process utility systems is a prime consideration for both their design and operation. This paper combines the optimization of utility system performance with reliability theory based on Markov analysis. Operation mode is first to be considered, e.g. hot standby, cold standby, load-sharing, etc. Downtime during start up has been considered for the first time. When optimising the working load, the downstream processes are also considered, so as to minimize the total penalty cost due to shutting down of the units serviced by the utility system. The proposed methodology combines the operation and design problems and optimizes them simultaneously. © 2012 Pleiades Publishing, Ltd. Source

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