A hydrogen compressor is a device that increases the pressure of

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-to ...

by reducing its volume resulting in compressed hydrogen or

liquid hydrogen Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully l ...

. Traditionally, applications for hydrogen compressors included Chlorine electrolyser and many chemical applications like the production of hydrogen peroxide (HPPO). The newer applications related to green and environmentally friendly technologies include fuel cells and electrolysis for hydrogen production.

Compressor vs pump

Hydrogen compressors are closely related to hydrogen pumps and

gas compressor A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can tran ...

s: both increase the pressure on a

fluid In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...

and both can transport the fluid through a

pipe Pipe(s), PIPE(S) or piping may refer to: Objects * Pipe (fluid conveyance), a hollow cylinder following certain dimension rules ** Piping, the use of pipes in industry * Smoking pipe ** Tobacco pipe * Half-pipe and quarter pipe, semi-circular ...

. As gases are compressible, the compressor also reduces the volume of hydrogen gas, whereas the main result of a pump raising the pressure of a

liquid A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, ...

is to allow the

to be transported elsewhere.

Types

Reciprocating piston compressors

A proven method to compress hydrogen is to apply reciprocating piston compressors. Widely used in refineries, they are the backbone of refining crude oil. Reciprocating piston compressors are commonly available as either oil-lubricated or non-lubricated; for high pressure (350 - 700 bar), non-lubricated compressors are preferred to avoid oil contamination of the hydrogen. Typical drive power is in the order of magnitude of Megawatts (300kW-15MW). Expert know-how on piston sealing and packing rings can ensure that reciprocating compressors outperform the competing technologies in terms of MTBO (Mean Time Between Overhaul).

Ionic liquid piston compressor

ionic liquid piston compressor An ionic liquid piston compressor, ionic compressor or ionic liquid piston pump is a hydrogen compressor based on an ionic liquid piston instead of a metal piston as in a piston-metal diaphragm compressor. Principle An ionic liquid compressor t ...

is a hydrogen compressor based on an

ionic liquid An ionic liquid (IL) is a salt in the liquid state. In some contexts, the term has been restricted to salts whose melting point is below a specific temperature, such as . While ordinary liquids such as water and gasoline are predominantly made of ...

piston instead of a metal piston as in a piston-metal

diaphragm compressor {{Short description, Variant of the reciprocating compressor A diaphragm compressor is a variant of the classic reciprocating compressor with backup and piston rings and rod seal. The compression of gas occurs by means of a flexible membrane, instea ...

Electrochemical hydrogen compressor

A multi-stage electrochemical hydrogen compressor incorporates a series of membrane-electrode-assemblies (MEAs), similar to those used in

proton-exchange membrane fuel cell Proton-exchange membrane fuel cells (PEMFC), also known as polymer electrolyte membrane (PEM) fuel cells, are a type of fuel cell being developed mainly for transport applications, as well as for stationary fuel-cell applications and portable ...

s; this type of compressor has no moving parts and is compact. The electrochemical compressor works similar to a fuel cell, a voltage is applied to the membrane and the resulting electric current pulls hydrogen through the membrane. With electrochemical compression of hydrogen, a pressure of 14500 psi (1000bar or 100MPa) is achieved. A patent is pending claiming an

exergy efficiency Exergy efficiency (also known as the second-law efficiency or rational efficiency) computes the effectiveness of a system relative to its performance in reversible conditions. It is defined as the ratio of the thermal efficiency of an actual system ...

of 70 to 80% for pressures up to 10,000 psi or 700 bars. A single stage electrochemical compression to 800 bar was reported in 2011.

Hydride compressor

In a hydride compressor, thermal and pressure properties of a

hydride In chemistry, a hydride is formally the anion of hydrogen( H−). The term is applied loosely. At one extreme, all compounds containing covalently bound H atoms are called hydrides: water (H2O) is a hydride of oxygen, ammonia is a hydride ...

are used to absorb low-pressure hydrogen gas at ambient temperatures and then release high-pressure hydrogen gas at higher temperatures; the bed of hydride is heated with hot water or an electric coil.

Piston-metal diaphragm compressor

Piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-t ...

-metal

s are stationary high-pressure compressors, four-staged water-cooled, 11–15 kW, 30–50 Nm3/h 40 MPa for dispensation of hydrogen. Since compression generates heat, the compressed gas is to be cooled between stages making the compression less adiabatic and more

isothermal In thermodynamics, an isothermal process is a type of thermodynamic process in which the temperature ''T'' of a system remains constant: Δ''T'' = 0. This typically occurs when a system is in contact with an outside thermal reservoir, an ...

. The default assumption on diaphragm hydrogen compressors is an adiabatic efficiency of 70%. Used in hydrogen stations.

Guided rotor compressor

The guided rotor compressor (GRC) is a positive-displacement rotary

compressor A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can tr ...

based upon an envoluted

trochoid In geometry, a trochoid () is a roulette curve formed by a circle rolling along a line. It is the curve traced out by a point fixed to a circle (where the point may be on, inside, or outside the circle) as it rolls along a straight line. If the ...

geometry which utilizes a parallel trochoid curve to define its basic compression volume. It has a typical 80 to 85% adiabatic efficiency.

Linear compressor

The single-piston

linear compressor A linear compressor is a gas compressor where the piston moves along a linear track to minimize friction and reduce energy loss during conversion of motion. This technology has been successfully used in cryogenic applications which must be oilless ...

uses dynamic counterbalancing, where an auxiliary movable mass is flexibly attached to a movable piston assembly and to the stationary compressor casing using auxiliary mechanical springs with zero vibration export at minimum electrical power and current consumed by the motor.Valved linear compressor
It is used in

cryogenic In physics, cryogenics is the production and behaviour of materials at very low temperatures. The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cr ...

References

External links

2004-Osti Hybrid Compressor-Expander
{{DEFAULTSORT:Hydrogen Compressor Gas compressors Hydrogen technologies Industrial gases