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Pinch Technology: Basics for Beginners

Nov 08 2010 01:30 PM | Mukesh Sahdev in Heat Transfer *****

Future Outlook

The development of Pinch Technology started in the late 1970s and still continues. Besides applications in energy conservation, new developments in Pinch Analysis are being made in the areas of water use minimization, waste minimization, hydrogen management, plastics manufacturing, and others. A few of key areas of research are mentioned decribed below.

Regional Energy Analysis

By examining the net energy demands of different companies combined, the potential for sharing heat between companies can be identified. These analyses can lend insight into the amount and temperature of waste heat in an industrial area that is available for export. Depending on the temperature of this waste heat, it can be used for district heating or power generation.

Total Site Analysis

Typically, refinery and petrochemical processes operate as parts of large sites or factories. These sites have several processes serviced by a centralized utility system. There is both consumption and recovery of process steam via the steam mains. The site imports or exports power to balance the on-site power generation. The process stream heating and cooling demands, and co-generation potential, dictate the site-wide fuel demand via the utility system.

In such large sites, usually the individual production processes and the central services are controlled by different departments which operate independently. The site infrastructure usually suffers from inadequate integration. To improve integration, a simultaneous approach to consider individual process issues alongside sitewide utility planning is necessary. Similar to a single process, a Total Site Analysis using Pinch Technology can be used to calculate energy targets for the entire site. For example, how much low pressure, medium pressure, and high pressure steam should the site be using? How much steam can be raised and how much power it can generate? This also helps to identify key process changes that will lower the overall site utility consumption.

Network Pinch

When optimizing energy consumption in an existing industrial process, a number of practical constraints must be recognized. Traditional Pinch Technology focuses on new network designs. Network Pinch addresses the additional constraints in problems associated with existing facilities. This analysis identifies the heat exchanger forming the bottleneck to increasing heat recovery. Then provides a systematic approach to remove this bottleneck. This step-by-step method provides an approach for implementing energy savings in a series of consecutive projects.

Top Level Analysis

Gathering the required data in industrial areas is not an easy task. With a Top Level Analysis, only efficiencies and constraints of the utility system are used to determine which utility is worth saving. Data can be gathered from those processes or units that use these utilities. A pinch analysis can then be performed on this equipment.

Optimization of Combined Heat and Power

Typically, multiple steam turbines are used in complex steam systems. CHP optimization gives a way to determine the load distribution in a network of turbines with a given total load.

Water Pinch

In view of rising fresh water costs and more stringent discharge regulations, Pinch Analysis is helping companies to systematically minimize freshwater and wastewater volumes. Water Pinch is a systematic technique for analyzing water networks and reducing water costs for processes. It uses advanced algorithms to identify and optimize the best water reuse, regeneration, and effluent treatment opportunities. It has also helped to reduce losses of both feedstock and valuable products in effluent streams.

Hydrogen Pinch

The Pinch Technology approach applied to hydrogen management is called Hydrogen Pinch. Hydrogen Pinch enables a designer to set targets for the minimum hydrogen plant production and/or imports without the need for any process design. Methods have also been developed for the design of hydrogen distribution networks in order to achieve the targets. Hydrogen Pinch also lends insight into the effective use of hydrogen purification units.

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