Fuel Cell: Hydrogen Production

On the road of pursuing energy-saving and low carbon, hydrogen energy has become an area concerned by the global for its excellent performance. How to ensure sufficient sources of hydrogen energy is the key to promote the hydrogen energy society in the world, which is also a focus that many countries are optimistic about.

At present, 96% of the world's hydrogen production raw materials are derived from chemical reforming of traditional energy sources, mainly including natural gas reforming, alcohol reforming, and coke oven gas, and about 4% are from electrolyzed water.

Also, the special national conditions have made Japan whose layout in the field of hydrogen energy has also been very prominent show a strong interest in exploring new energy. Japan vigorously advocates a "hydrogen energy society" and actively applies hydrogen energy to all aspects of social production and life, which plans to form the three pillars of domestic secondary energy like electricity and heat. In exploring the source of hydrogen, Japan has made many attempts, especially how to develop hydrogen energy with zero carbon.

At present, hydrogen production from renewable energy in Japan is in a booming stage. The hydrogen production from brine electrolysis accounts for 63% of the scale of hydrogen production in Japan, followed by natural gas, ethylene, and coke oven gas. But in fact, most of the electricity used in the water electrolysis process is still ordinary industrial electricity, and the raw materials are mainly fossil energy such as oil and natural gas. This method of hydrogen production cannot meet the development needs of clean energy. Exploring low-carbon or even zero-carbon hydrogen production technology has become a key development direction in Japan.

The Hydrogen of Fuel Cells in China Mainly Comes from the By-Product Hydrogen of Chlor-Alkali Industry

China is the world's largest hydrogen production country, and its industrial hydrogen production leads the world. At present, hydrogen production methods in China mainly include industrial by-product hydrogen production, fossil fuel hydrogen production, chemical raw material hydrogen production, and electrolysis water hydrogen production. The method mainly relies on hydrogen production from coal gasification and industrial by-product hydrogen production. In 2018, China's coal gasification hydrogen production reached 10 million tons, and the industrial by-product hydrogen production capacity reached 8 million tons.

Considering that the hydrogen produced by coal gasification contains sulfur, with a not high purity, and also takes a long time and pollutes the environment. If the process of desulfurization and denitrification is carried out, the cost of hydrogen production will increase. Therefore, when considering the source of hydrogen used in fuel cells, it is mainly dependent on by-product hydrogen from the Chlor-Alkali industry, natural gas, methanol, and liquid ammonia.

Industrial by-product hydrogen mainly includes Chlor-Alkali by-product hydrogen, coke oven gas hydrogen production, and light hydrocarbon cracking hydrogen production. Among them, the industrial production of Chlor-Alkali uses saltwater as the raw material using the diaphragm method or ion exchange membrane method to produce products including caustic soda, polyvinyl chloride, chlorine, and hydrogen. Most of the domestic Chlor-Alkali industry uses ion-exchange membrane electrolysis, which has low carbon monoxide content and no organic sulfur and inorganic sulfur in fossil fuels, thus, it is a better choice for fuel cell hydrogen sources. The by-product hydrogen of Chlor-Alkali has the characteristics of less difficulty in purifying hydrogen, low energy consumption, and a high degree of automation, and no pollution.

In 2019, China's caustic soda production reached 34.644 million tons, a year-on-year increase of 1.3%. By-produce 25 kg of hydrogen can be produced by every one ton of caustic soda. At present, the by-product hydrogen of domestic Chlor-Alkali plants is mainly used for the preparation of hydrochloric acid, other chemicals, and the combustion to release heat, while about 30% of the by-product hydrogen is directly vented. This part of the vented by-product hydrogen can theoretically supply about 1 million fuel cell vehicles.

By-product hydrogen companies in China China's Chlor-Alkali industry mainly include Hongda Xingye and Befar Group, both of which are the important propylene oxide and caustic soda producers, with 1 million tons of caustic soda production capacity, and about 25,000 tons of hydrogen by-products each year. Befar Group has an annual caustic soda production capacity of 650,000 tons and a by-product of 17,000 tons of hydrogen. Zhejiang Jiahua has completed the entire industry chain covering hydrogen production, hydrogen storage and transportation, and hydrogenation. The existing by-product hydrogen of Chlor-Alkali is 10,000 tons.

Hydrogen Production from Water Electrolysis Is Expected to Become One of the Mainstream Technologies in the Future with the Reduction of Power Supply Costs

The principle of hydrogen production by electrolysis of water is that in an electrolytic cell composed of electrodes, electrolytes, and diaphragms, with an electric current passing through the aqueous electrolyte solution. After the water is electrolyzed, hydrogen is generated at the cathode and oxygen is generated at the anode. There are three main technical routes, including AE, PEM, and SOE. Among them, the lowest cost and most mature technology is AE; Although the process of PEM is simple, the cost is relatively high as it uses precious metal electrocatalysts; SOE is still in the laboratory research and development state.

Hydrogen production by the electrolysis of water technology has the advantages of simple process, no pollution, and high product purity, but it is temporarily not possible for large-scale promotion and application due to the large consumption and high cost of power.

At present, as an important raw material for hydrogen production by electrolysis of water, power hinders the development of hydrogen production by electrolysis due to its high cost. In recent years, China's wind power and photovoltaics have developed rapidly, and the prices of wind power and photovoltaic power have dropped to the price level of coal power under the strong state subsidies, in which the cost of hydrogen production from electrolysis of water will also be further reduced.

In the short-medium term, as the mainstream process of hydrogen production from coal is limited by cost and environmental pressures, the industry growth is almost slim, which is eliminated by the market finally. The low-cost industrial by-product hydrogen production is limited by the production capacity of the main product, in which there is an upper limit on the hydrogen production capacity. In the long run, the drop in electricity price costs will further reduce the cost of hydrogen production from electrolyzed water. The hydrogen production from electrolyzed water with high production capacity and no pollution is expected to become one of the mainstream technologies of hydrogen supply in the future.

Custom Reporting