【Tech Lecture】Methods of Hydrogen Production

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【Tech Lecture】Methods of Hydrogen Production: The construction of fuel cell infrastructure in China is accelerating, in order to prepare fully for the commercialization of fuel cell vehicles. Hydrogenation infrastructure is an essential support for the development of fuel cells. The low-cost transportation of hydrogen is another challenge that needs to be addressed, and the availability of high-purity hydrogen suitable for fuel cell vehicles is also an important issue. This article will primarily introduce the production process of hydrogen, the essential material for fuel cells, and analyze and compare the advantages and disadvantages of different methods. Question 1: What are the methods for industrial hydrogen production, and what are their respective principles? 2. What are the advantages and disadvantages of each method? What is the optimal adaptation scenario? Industrial hydrogen production involves many methods, each with its own advantages and limitations. The traditional methods for producing hydrogen are primarily water electrolysis and the use of fossil fuels. Water electrolysis not only requires a high amount of energy but is also costly; under standard conditions, as much as 5.5 kW·h of electrical energy is needed to produce one cubic meter of hydrogen, resulting in high production costs. Producing hydrogen from fossil fuels requires a large amount of external heat for the reaction; this results in significant loss of chemical energy as well as emissions of the greenhouse gas CO2. 1. There are numerous methods for industrial hydrogen production. Hydrogen is not only an important industrial raw material and reducing agent but also a necessary fuel for fuel cells. With the advancement and widespread adoption of fuel cells, as fuel cell vehicles enter mature markets, hydrogen consumption will also increase at an astonishing rate. Currently, there are several main methods for industrial hydrogen production: one is to produce hydrogen using fossil fuels ； The second is to extract hydrogen from chemical by-products ； Third, hydrogen is produced by converting methanol from biological sources into methane; fourth, water electrolysis is carried out using natural energies such as solar and wind energy. http://5b0988e595225.cdn.sohucs.com/images/20170904/5eb591f0730542279a92d63ad0c09338.jpeg1.1 Hydrogen production from fossil fuels: This is a traditional method for producing hydrogen, and it remains an established process; however, it still relies on fossil fuels, and it releases greenhouse gases such as carbon dioxide, which reduces the environmental benefits of fuel cells. The fossil fuel commonly used for hydrogen production is natural gas. The process of producing hydrogen from natural gas involves a chemical reaction between the alkanes in natural gas and water vapor, under certain pressure, high temperature, and in the presence of a catalyst. The converted gas undergoes heat exchange in a boiling pot before entering the shift reactor where CO is converted into H2 and CO2. After heat exchange, condensation, and gas-liquid separation, the gas is routed, under program control, through adsorption towers equipped with three specific adsorbents; pressure swing adsorption (PSA) is used to adsorb N2, CO, CH4, and CO2, thereby extracting the product hydrogen. http://5b0988e595225.cdn.sohucs.com/images/20170904/8dafbfe2fef94e6caeee6531b03f906d.jpeg1.2 Hydrogen production from industrial by-products: The technology for producing hydrogen from coke oven gas, which is a by-product of the coking industry, involves the use of pressure swing adsorption to extract pure hydrogen from this gas. The basic principle is to utilize the selectivity of solid adsorbents in absorbing gases, as well as the fact that the amount of gas absorbed by the adsorbent decreases as its partial pressure drops, in order to separate gas mixtures and regenerate the adsorbent, thereby achieving the purification of hydrogen. 1.3 Hydrogen production via methanol reforming – Methanol steam reforming is a hydrogen production technology that emerged abroad in the 1980s; countries such as Canada, the United Kingdom, and Australia have conducted extensive research in this area. After decades of in-depth research, Guangdong Hejide Energy Technology Co., Ltd. has developed a highly mature hydrogen production process. It is a pioneer in the field of compact, mobile methanol-based hydrogen production in China, and has integrated this technology with fuel cell power generation technology. This integration has been successfully applied in areas such as new energy vehicles and communication base stations, offering excellent prospects for further use. http://5b0988e595225.cdn.sohucs.com/images/20170904/2226443603dd464d88dbee2fe38314d3.jpeg 1.4 Hydrogen production by water electrolysis: Hydrogen can also be obtained through the traditional method of water electrolysis, but due to its high energy consumption, few new installations are built using this method, aside from those that already exist. 2. The various methods have their own advantages and disadvantages, and different methods are suitable for different needs. As can be seen from the above, there are currently multiple ways to produce hydrogen in industry. However, it seems that these methods all have their own advantages and limitations. Both natural gas-based hydrogen production and coke oven gas-based hydrogen production are suitable for large-scale hydrogen production, but they are both limited by the availability of raw materials and are polluting. In terms of environmental protection, although hydrogen production from coke oven gas utilizes a by-product of coking, the pollutants in it cannot be removed, and hydrogen production from natural gas still requires fossil fuels as raw materials. In contrast, hydrogen production via methanol reforming features low investment, rapid construction, and no pollution; moreover, methanol can be used as a raw material more flexibly. However, it is difficult to carry out large-scale hydrogen production using this method. Given that fuel cells are set to become the main source of energy in the future, the demand for hydrogen production capacity will continue to increase. Therefore, hydrogen production from natural gas and coke oven gas finds it difficult to break free from reliance on fossil feedstocks. In contrast, hydrogen production from methanol, when integrated closely with fuel cells, allows for the immediate use of hydrogen, thereby addressing issues related to hydrogen storage, safety, and cost. http://5b0988e595225.cdn.sohucs.com/images/20170904/2f4fc985d68d407c886035e94bbad008.jpeg From an economic perspective, the cost of hydrogen production depends to a large extent on the cost of raw materials, and this cost fluctuates significantly with changes in the prices of those raw materials. Given the current levels of raw material prices, hydrogen production from coke oven gas and natural gas is less costly. However, when used in fuel cells, additional costs are required for hydrogen stations, hydrogen tanks, transportation, etc. Methanol reformation for hydrogen production can be directly combined with fuel cells, eliminating the need to build expensive hydrogen refueling stations and hydrogen tanks. The price of natural gas for non-residential use is currently being gradually made market-driven. On November 18, 2015, the **National Development and Reform Commission announced a reduction in the price of natural gas at the supply points for non-residential users, by 0.7 yuan per cubic meter. Currently, the price of non-commercial natural gas is around 2.7 to 3.0 yuan per m3, while the cost of hydrogen production is approximately 1.5–1.7 yuan per km3. Coke oven gas is a by-product generated during the coking process in coke manufacturing plants; it was previously burned as fuel and then released into the atmosphere at high altitudes. Nowadays, when used as a chemical raw material, its price is generally below 0.4 yuan per m3. Therefore, the cost of producing hydrogen from coke oven gas can be lower than 1.39 yuan per km3, which is lower than the cost of producing hydrogen from natural gas. In June 2016, the average price of methanol was 1,860 yuan per ton, so the cost of hydrogen production was 1.37 yuan per km3. Based on the current prices of various raw materials, the economic viability of hydrogen production via methanol reforming is quite significant. Considering the advantages, disadvantages, and costs of current industrial hydrogen production methods, methanol reformation for hydrogen production has the following three advantages: (1) The raw materials used for hydrogen production are widely available and inexpensive. As a common chemical raw material, methanol can be produced from fossil resources as well as from biomass (all organic substances derived directly or indirectly from the photosynthesis of green plants) ； (2) High utilization rate of hydrogen; the methanol molecule has the formula CH3OH, contains a high amount of hydrogen, has a high energy density, and yields a high amount of hydrogen gas ； (3) The hydrogen production unit is simple, and methanol is easy to store and transport; thus, methanol-based hydrogen production units that are modular or mobile can be developed. Based on the current practices regarding hydrogen use in fuel cell vehicles in our country, methanol reformation for hydrogen production is also the preferred method. The fuel hydrogen used in the fuel cell sedan project, which is part of the major special initiative for hydrogen-powered vehicles undertaken by Guangdong Hejide, is produced entirely from methanol through on-the-spot hydrogen generation. This approach effectively addresses the safety issues associated with the use of hydrogen energy, as well as the costs involved in building large-scale hydrogen refueling infrastructure, thereby solving the problem of whether a hydrogen economy is economically viable. 3. In summary, based on the current situation, the technology for hydrogen production that is relatively inexpensive and mature is methanol reformation. With technological advancements and the further expansion of renewable energy generation, methanol reformation for hydrogen production will be the cheaper technology in the future.