Comparative Analysis of Hydrogen Production by Four Fuel Cells for Hydrogen Production from Fossil Fuel and Hydrogen Production from Methanol Cracking

At present, there are several main methods for industrial hydrogen production: one is to use hydrogen from fossil fuels; the other is to extract hydrogen from chemical by-products; the third is to use hydrogen from methanol to produce hydrogen, and the fourth is to use solar energy, wind energy, etc. Energy conducts electrolysis of water.

Hydrogen is not only an important industrial raw material and reducing agent, but also a necessary fuel for fuel cells. With the promotion and popularization of fuel cells, fuel cell vehicles have entered a mature market, and hydrogen consumption will increase at an alarming rate. At present, there are several main methods for industrial hydrogen production: one is to use hydrogen from fossil fuels; the other is to extract hydrogen from chemical by-products; the third is to use hydrogen from methanol to produce hydrogen, and the fourth is to use solar energy, wind energy, etc. Energy conducts electrolysis of water.

Hydrogen production method

Fossil fuel hydrogen production

Hydrogen production from fossil fuels is a relatively traditional method of hydrogen production and an old process for hydrogen production. However, it is still inseparable from the dependence on fossil fuels and emits greenhouse gases such as carbon dioxide, resulting in a decrease in the environmental value of fuel cells. The fossil fuel generally used for hydrogen production is natural gas. The process of producing hydrogen from natural gas is: under certain pressure and high temperature and catalyst, the alkane and water vapor in the natural gas react chemically. The reformed gas is converted into H2 and CO2 by heat exchange in a boiling pot and into a converter. After heat exchange, condensation, steam-water separation, the gas is sequentially passed through an adsorption tower equipped with three specific adsorbents, and pressure-adsorption (PSA) is used to adsorb N2, CO, CH4, and CO2 to extract hydrogen. .

Natural gas hydrogen production principle

Coke oven gas to produce hydrogen

Coke oven gas hydrogen production technology uses a pressure swing adsorption process to extract pure hydrogen from the coke oven gas produced by the coking industry. The basic principle is that the adsorption of the gas by the solid adsorbent is selective, and the adsorption amount of the gas on the adsorbent decreases with the decrease of the partial pressure thereof, thereby realizing the separation of the gas mixture and the regeneration of the adsorbent to achieve purification. The purpose of hydrogen.

Principle of hydrogen production from coke oven gas

Methanol cracking hydrogen production

The process of hydrogen production by methanol cracking is a mixture of methanol and demineralized water in a certain ratio, and the steam of the mixture heated to about 270 ° C occurs under the action of a catalyst (Cu-Zn-Al) or (Cu-Zn-Cr). Catalytic cracking and conversion reactions.

Principle of hydrogen production by methanol cracking

Electrolyzed water to produce hydrogen

Hydrogen can also be obtained by conventional electrolyzed water method, but this method has few new equipment except for the built-up equipment due to excessive energy consumption.

Electrolyzed water to produce hydrogen

According to the above methods, there are various ways of producing hydrogen in the industry. These methods have their own advantages and limitations. Both hydrogen production from natural gas and hydrogen production from coke oven gas are suitable for large-scale hydrogen production, but are also limited by the supply of raw materials and are polluting. In terms of environmental protection, although coke oven gas hydrogen production is a by-product of coking, it cannot remove pollutants, and natural gas hydrogen production still requires fossil fuels as raw materials. In contrast, methanol cracking hydrogen production has the characteristics of low investment, fast construction, no pollution, and methanol can be more flexible as a raw material, but it is difficult to produce hydrogen by large-scale hydrogen production by methanol cracking.

Various hydrogen production advantages and disadvantages

From the economic point of view, the cost of hydrogen production depends largely on the cost of raw materials, which is very variable with the price of raw materials. As far as the current raw material price level is concerned, coke oven gas produces hydrogen and natural gas to produce hydrogen at a lower cost.

In view of the advantages and disadvantages of current industrial hydrogen production methods and cost considerations, if there is abundant coke oven gas resources near the hydrogen plant, coke oven gas hydrogen production technology is the preferred process technology solution. Considering the requirements of the scale of hydrogen production, natural gas hydrogen production technology is also a preferred solution in the case of obtaining natural gas resources. Methanol cracking hydrogen production has large fluctuations in cost, and the hydrogen production scale is small, but the device cost is low, so it is suitable for intermittent and supplementary hydrogen production.