High-purity hydrogen production process

Hydrogen is an important gas widely used in industry, medical fields and laboratories. Ordinary hydrogen can be obtained through a variety of production processes, but in order to meet the needs of specific applications, the production of high-purity hydrogen is an essential process. The following are the main methods and processes for high-purity hydrogen production.

The purity level of hydrogen is usually divided according to international standards based on the concentration of impurities. The main purity levels of hydrogen are as follows:

• Industrial grade hydrogen: 99.5% purity, suitable for non-critical industrial environments.
• Pure hydrogen: 99.99% purity, used in the food and beverage industry.
• High-purity hydrogen: 99.999% purity, this grade is used in the pharmaceutical and electronics manufacturing industries.

Ultra-high purity hydrogen: purity between 99.9999% and 99.99999%, impurity content is usually measured in parts per billion (ppb). Ultra-high purity hydrogen is mainly used in semiconductor manufacturing and pharmaceutical production.

Methods for producing high-purity hydrogen: Steam methane reforming (SMR) + purification equipment

Process description: Steam methane reforming (SMR) is the main industrial method for producing hydrogen. This method uses high-temperature steam to react with methane (natural gas) to produce hydrogen and carbon monoxide. Subsequently, the hydrogen yield is further increased through the water-gas shift reaction.

Process steps

1. Pretreatment: Remove impurities such as sulfides from the raw materials.
2. Reforming reaction: At high temperature (700-1100°C) and high pressure, methane reacts with steam in the presence of a catalyst to produce hydrogen and carbon monoxide.
3. Water-gas shift reaction: Carbon monoxide reacts with water vapor through a catalytic reaction to produce more hydrogen and carbon dioxide.
4. Purification: Carbon dioxide and other impurities are removed through pressure swing adsorption (PSA) or membrane separation technology to obtain high-purity hydrogen.

Water electrolysis: Process description Water electrolysis is a method of decomposing water to produce hydrogen and oxygen through electric current.

Electrolyzer: Water is decomposed into hydrogen and oxygen through electric current in an electrolyzer. The electrolyzer can be an alkaline electrolyzer (AEC), a proton exchange membrane electrolyzer (PEMEC) or a solid oxide electrolyzer (SOEC).

Hydrogen collection: The hydrogen produced at the cathode is collected by a collection system.

Purification: Water vapor and other impurities in hydrogen are removed by adsorption, condensation and other methods to obtain high-purity hydrogen.

Partial oxidation (POX) + purification equipment

Process description: Partial oxidation is a method of partially burning hydrocarbons under controlled conditions to produce hydrogen and carbon monoxide.

Process steps

1. Pretreatment: Remove impurities from the raw materials.
2. Partial oxidation reaction: At high temperature (1300-1500°C) and pressure, methane and oxygen are partially burned in the presence of a catalyst to produce hydrogen and carbon monoxide.
3. Water gas shift reaction: The hydrogen yield is further increased by the water gas shift reaction.
4. Purification: Carbon dioxide and other impurities are removed by pressure swing adsorption (PSA) or membrane separation technology to obtain high-purity hydrogen.

Methanol cracking: Process description Methanol cracking is the process of using methanol and water vapor to generate hydrogen and carbon monoxide at high temperature.

Process steps

1. Pretreatment: Remove impurities in methanol.
2. Cracking reaction: Methanol reacts with water vapor to generate hydrogen and carbon monoxide at high temperature (250-300°C) and in the presence of a catalyst.
3. Water-gas shift reaction: Carbon monoxide is converted into carbon dioxide and more hydrogen through the water-gas shift reaction.
4. Purification: Carbon dioxide and other impurities are removed by pressure swing adsorption (PSA) or membrane separation technology to obtain high-purity hydrogen.

Purification method of high-purity hydrogen

For users who need hydrogen with a purity of more than 99.998% and have a large gas demand, using a hydrogen generator to produce ordinary hydrogen, coupled with purification equipment, is an economical and effective method that can reduce both initial equipment investment and operating costs. Commonly used purification methods include hydrogen purification and carbon purification: Hydrogen generator + hydrogen purification equipment
This method first produces ordinary hydrogen from a hydrogen generator. Under the action of a catalyst, trace impurities in hydrogen react with specific reactants to generate water or other removable compounds, and then remove water and other impurities through an adsorption drying device to obtain high-purity hydrogen.

Equipment features

1. Adopts internationally leading, high-efficiency deoxygenation catalysts with excellent activity.
2. A heat exchanger is used to reduce the temperature of the deoxygenated gas, without cooling water.
3. Fully automatic control, optional mass flow controller to automatically add hydrogen.Regenerated gas emissions are low, saving energy.

Hydrogen generator + carbon purification equipment

This method uses a carbon-based catalyst to react trace oxygen in hydrogen with carbon to remove oxygen, and then passes through an adsorption drying device to remove carbon dioxide and dust to obtain high-purity hydrogen.

Equipment features

1. Provides safe and stable gas production, and the purity of hydrogen is always higher than 99.9995%.
2. Dual tower switching, no downtime required for desiccant replacement or major maintenance.
3. Drying towers are automatically controlled, and adsorber switching is performed by the PC according to a set schedule.

Application of high-purity hydrogen

High-purity hydrogen has a purity of more than 99.998%, and is widely used in various fields due to its excellent purity and stability.

Electronics industry

High-purity hydrogen plays a vital role in the electronics industry, especially in semiconductor manufacturing. It is used as a carrier gas and protective gas in processes such as chemical vapor deposition to minimize metal contamination and ensure the quality of semiconductor chips. In addition, high-purity hydrogen supports clean environments and stable conditions in lithography, etching, and thin film deposition equipment.

Medical field

In the medical field, high-purity hydrogen is indispensable. It is often used as an anesthetic gas for anesthetizing patients in operating rooms. In addition, it is also crucial in gas delivery systems, helping to maintain the normal operation of ventilators and anesthesia machines.

Energy field

In the energy field, high-purity hydrogen is widely used in fuel cell technology as a clean fuel. Fuel cells use hydrogen to react with oxygen to generate electricity and water, achieving efficient and environmentally friendly energy conversion.