Hydrogen pinch
Encyclopedia
Hydrogen pinch analysis is a hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 management method that originates from the concept of heat pinch analysis
Pinch analysis
Pinch analysis is a methodology for minimising energy consumption of chemical processes by calculating thermodynamically feasible energy targets and achieving them by optimising heat recovery systems, energy supply methods and process operating conditions...

. HPA is a systematic technique for reducing hydrogen consumption and hydrogen generation through integration of hydrogen-using activities or processes in the petrochemical industry, petroleum refineries hydrogen distribution networks and hydrogen purification.

Principle

A mass analysis is done by representing the purity and flowrate for each stream from the hydrogen consumers (sinks), such as hydrotreaters, hydrocrackers, isomerization units and lubricant
Lubricant
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...

 plants and the hydrogen producers (sources), such as hydrogen plants and naphtha
Naphtha
Naphtha normally refers to a number of different flammable liquid mixtures of hydrocarbons, i.e., a component of natural gas condensate or a distillation product from petroleum, coal tar or peat boiling in a certain range and containing certain hydrocarbons. It is a broad term covering among the...

 reformers, streams from hydrogen purifier
Hydrogen purifier
A hydrogen purifier is a device to purify hydrogen if hydrogen production is done from hydrocarbon sources, the ultra-high purified hydrogen is needed for applications like PEM fuel cells...

s, membrane reactor
Membrane reactor
A membrane reactor is a piece of chemical equipment that combines a catalyst-filled reaction chamber with a membrane to add reactants or remove products of the reaction.Chemical reactors making use of membranes are usually referred to as membrane reactors...

s, pressure swing adsorption
Pressure swing adsorption
Pressure swing adsorption is a technology used to separate some gas species from a mixture of gases under pressure according to the species' molecular characteristics and affinity for an adsorbent material. It operates at near-ambient temperatures and so differs from cryogenic distillation...

 and continuous distillation
Continuous distillation
Continuous distillation, a form of distillation, is an ongoing separation in which a mixture is continuously fed into the process and separated fractions are removed continuously as output streams. A distillation is the separation or partial separation of a liquid feed mixture into components or...

 and off-gas streams from low- or high-pressure separators. The source-demand diagram shows bottlenecks, surplus or shortages. The hydrogen pinch is the purity at which the hydrogen network has neither hydrogen surplus nor deficit.

After the analysis REFOPT from the Centre for Process Integration at The University of Manchester is used as a tool for process integration with which the process is optimized. The methodology was also developed into commercial software by companies such as Linnhoff March and AspenTech. The Aspen product incorporated the work of Nick Hallale (formerly a lecturer at University of Manchester) and was the first method to consider multiple components, rather than a pseudo-binary mixture of hydrogen and methane.

History

The first assessment based on cost and value composite curves of hydrogen resources of a hydrogen network was proposed by Tower et al. (1996). Alves developed the hydrogen pinch analysis approach based on the concept of heat pinch analysis
Pinch analysis
Pinch analysis is a methodology for minimising energy consumption of chemical processes by calculating thermodynamically feasible energy targets and achieving them by optimising heat recovery systems, energy supply methods and process operating conditions...

 in 1999. Nick Hallale and Fang Liu extended this original work, adding pressure constraints and mathematical programming for optimisation. This was followed by developments at AspenTech, producing commercial software for industrial application.

See also


External links

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