Gerador de Hidrogênio por Craqueamento de Amônia

A tecnologia de produção de hidrogênio por decomposição de amônia, como um processo de preparação de gás maduro e eficiente, ocupa uma posição importante no campo da produção industrial. Seu princípio fundamental é decompor com precisão a amônia (NH₃) em um gás misto composto por 25% de nitrogênio (N₂) e 75% de hidrogênio (H₂) em volume, sob condições específicas de equipamento e processo. Essa proporção deriva da fórmula química da amônia: a cada duas moléculas de amônia, a decomposição resulta em uma molécula de nitrogênio e três moléculas de hidrogênio, formando naturalmente um sistema estável de mistura hidrogênio-nitrogênio. Graças às suas vantagens, como a disponibilidade de matérias-primas, o processo de preparação ecologicamente correto e a pureza do gás controlável, essa tecnologia tem sido amplamente aplicada em diversos segmentos industriais e se tornou uma das tecnologias-chave para o desenvolvimento de alta qualidade em indústrias como tratamento térmico, metalurgia e fabricação de vidro.

O fluxo completo do processo de produção de hidrogênio por decomposição de amônia pode ser dividido em três etapas principais: pré-tratamento da matéria-prima, reação de decomposição da amônia e purificação do gás. Essas etapas estão intimamente interligadas para garantir a qualidade do produto gasoso final. Em termos de matéria-prima, a amônia líquida de alta pureza é geralmente utilizada como substrato de reação. A amônia líquida apresenta facilidade de armazenamento, transporte seguro e alto teor de hidrogênio — seu teor de hidrogênio pode chegar a 17,6%, muito superior ao da maioria das fontes de hidrogênio gasoso. Além disso, a amônia líquida encontra-se em estado líquido em temperatura e pressão normais, exigindo muito menos espaço de armazenamento do que o hidrogênio gasoso, o que pode reduzir efetivamente o custo de armazenamento da matéria-prima para as empresas. Na etapa de pré-tratamento da matéria-prima, a amônia líquida é inicialmente transportada e vaporizada centralmente por meio de um dispositivo de distribuição dedicado. O dispositivo de distribuição permite a confluência estável e a regulação do fluxo de amônia líquida em múltiplos caminhos, garantindo um fornecimento uniforme e contínuo de amônia líquida e evitando o impacto das flutuações de fluxo na eficiência da reação subsequente. O processo de vaporização converte a amônia líquida em amônia gasosa por meio de aquecimento a baixa temperatura ou evaporação a baixa pressão em um ambiente fechado, removendo impurezas residuais que possam estar presentes nas matérias-primas, fornecendo um substrato de reação puro para a subsequente reação de decomposição. Após entrar no equipamento de decomposição de amônia, a amônia gasosa sofre reação de decomposição sob condições específicas de temperatura, pressão e catalisador. O núcleo do equipamento de decomposição de amônia consiste em um corpo de forno de reação e um sistema catalítico. O corpo do forno é geralmente feito de aço especial resistente a altas temperaturas e à corrosão, capaz de suportar perdas físicas e químicas em um ambiente de reação de alta temperatura e garantir a operação estável do equipamento a longo prazo. Durante a reação, a temperatura dentro do forno precisa ser controlada entre 800-900 °C, uma faixa de temperatura que pode ativar efetivamente a atividade do catalisador e acelerar a reação de decomposição da amônia. Os catalisadores mais comuns são à base de níquel, e alguns equipamentos de ponta adotam catalisadores compostos à base de rutênio ou ferro. Esses catalisadores apresentam características como alta eficiência catalítica, longa vida útil e forte resistência ao envenenamento, permitindo que a taxa de decomposição da amônia atinja mais de 99,9% e minimizando o resíduo de amônia não decomposta. Sob a ação do catalisador, as moléculas de amônia gasosa sofrem quebra de ligações e recombinação para formar uma mistura gasosa de hidrogênio e nitrogênio. Esse processo não requer a adição de outros reagentes, não emite gases nocivos e produz apenas uma mistura de hidrogênio e nitrogênio, o que está em consonância com o conceito de desenvolvimento da produção verde na indústria moderna.

Due to the reducibility of hydrogen and the inert protective property of nitrogen, the hydrogen-nitrogen mixture generated by ammonia decomposition hydrogen production technology has shown strong adaptability in the heat treatment industry and has become an indispensable core gas source for this industry. High-temperature brazing is one of the most widely used processes of hydrogen-nitrogen mixture in the heat treatment industry. This process is mainly used for the precision connection of metal components, especially suitable for the welding of parts made of stainless steel, copper alloy, aluminum alloy and other materials. In the high-temperature brazing process, the hydrogen-nitrogen mixture is used as a protective atmosphere. On the one hand, hydrogen can reduce the oxide film on the metal surface, avoiding defects such as pores and slag inclusions at the welding joint caused by oxidation, and ensuring the compactness and strength of the welding joint. On the other hand, nitrogen can isolate air, prevent reoxidation of metal components in a high-temperature environment, and maintain stable pressure inside the furnace, providing good conditions for the flow and wetting of brazing filler metal. Whether it is the brazing of precision parts in the aerospace field or the welding of engine components in the automobile manufacturing industry, the hydrogen-nitrogen mixture can significantly improve brazing quality, reduce scrap rate, and meet the strict requirements of high-end manufacturing for welding precision.

Bright annealing process is also inseparable from the hydrogen-nitrogen mixture generated by ammonia decomposition hydrogen production. Bright annealing is an important link in the deep processing of metal materials, aiming to eliminate internal stress generated during metal processing such as rolling and stamping, improve the toughness, ductility and surface finish of materials, and is often used for the treatment of metal materials such as stainless steel, copper strip and steel strip. In the bright annealing process, the hydrogen-nitrogen mixture is introduced into the annealing furnace as a protective atmosphere. In a high-temperature environment, hydrogen can reduce trace oxidative impurities on the metal surface, while nitrogen plays a role in diluting and isolating air, preventing the formation of oxide color on the metal surface, and ensuring that the metal material maintains a bright surface texture after annealing. Compared with the pure hydrogen atmosphere used in traditional annealing processes, the hydrogen-nitrogen mixture not only has lower cost but also higher safety, effectively reducing the risk of combustion and explosion of pure hydrogen atmosphere at high temperatures, and can achieve the same or even better annealing effect, making it the preferred protective atmosphere for bright annealing processes.

Metal powder reduction and aluminum alloy solution treatment processes are also important application scenarios for the hydrogen-nitrogen mixture from ammonia decomposition. The metal powder reduction process is mainly used to prepare high-purity metal powders, such as iron powder, copper powder, nickel powder, etc., which are widely used in fields such as powder metallurgy, electronic components, and magnetic materials. In the reduction process, hydrogen in the hydrogen-nitrogen mixture acts as a reducing agent, which can reduce oxidative impurities (such as iron oxide and copper oxide) in the metal powder to pure metal. At the same time, nitrogen acts as a protective gas to prevent reoxidation of the reduced metal powder, ensuring the purity and activity of the metal powder. The aluminum alloy solution treatment process improves the organizational structure of aluminum alloy and enhances its strength and hardness through high-temperature heating and rapid cooling. In the solution treatment process, the hydrogen-nitrogen mixture can effectively prevent oxidation and discoloration of aluminum alloy at high temperatures, promote the homogenization of the internal structure of aluminum alloy, improve the solution treatment effect, and enable aluminum alloy materials to better adapt to subsequent processing and application requirements.

In the powder metallurgy industry, the application of hydrogen-nitrogen mixture from ammonia decomposition runs through multiple core links such as raw material preparation, forming, and sintering. Powder metallurgy is a process for preparing metal products through powder pressing and sintering, which is widely used in mechanical manufacturing, auto parts, aerospace and other fields. In the sintering process, the hydrogen-nitrogen mixture is used as the sintering atmosphere. On the one hand, hydrogen can reduce the oxide film on the surface of metal powder, improve the bonding force between powder particles, and enhance the compactness and mechanical properties of the product. On the other hand, nitrogen can adjust the atmosphere pressure inside the furnace, inhibit the grain growth of metal powder, and ensure the uniform and fine organizational structure of the product. In addition, the hydrogen-nitrogen mixture can effectively remove volatile impurities generated during sintering, improve product purity, and enable powder metallurgy products to meet the requirements of high precision and high strength. Compared with other sintering atmospheres, the hydrogen-nitrogen mixture has the advantages of low cost and strong adaptability, and has become the mainstream atmosphere choice in the powder metallurgy industry.

In addition to the heat treatment and metallurgy industries, the hydrogen-nitrogen mixture from ammonia decomposition also plays an important role in float glass production. Float glass is a glass variety widely used in construction, automobile, electronics and other industries. Its production process has extremely high requirements on the atmosphere environment, which directly affects the transparency, flatness and surface quality of glass. In the tin bath link of float glass production, the hydrogen-nitrogen mixture is introduced into the bath as a protective atmosphere. Nitrogen can isolate air, prevent high-temperature tin liquid from oxidizing to form tin oxide, and avoid tin oxide adhering to the glass surface and affecting glass quality. Hydrogen can reduce trace tin oxide that may be generated in the tin bath, and adjust the reducibility of the atmosphere in the bath, ensuring a smooth and clean glass surface and improving the optical performance and mechanical strength of glass. In addition, the hydrogen-nitrogen mixture can maintain stable pressure inside the tin bath, prevent external air from entering, ensure the continuous and stable progress of float glass production, and improve production efficiency and product qualification rate.

The hydrogen-nitrogen mixture from ammonia decomposition also has important application value in nitriding furnace-related processes, mainly reflected in two aspects: nitriding furnace atmosphere adjustment and tail gas treatment. Nitriding treatment is an important process for surface strengthening of metal materials. By allowing nitrogen atoms to penetrate into the metal surface under high temperature and nitrogen-rich atmosphere, a hardened layer is formed, improving the wear resistance, corrosion resistance and fatigue strength of metal materials. In the adjustment of nitriding furnace atmosphere, the hydrogen-nitrogen mixture can be used as a basic atmosphere, mixed with ammonia, nitrogen and other gases to accurately adjust the nitrogen potential inside the furnace, meeting the requirements of different metal materials and different nitriding processes, and ensuring that the thickness, hardness and uniformity of the nitrided layer meet the design standards. At the same time, nitriding furnaces will generate tail gas containing trace ammonia, cyanide and other harmful substances during production. Direct emission will cause environmental pollution and pose safety hazards. Using tail gas treatment equipment related to ammonia decomposition hydrogen production technology, the tail gas of nitriding furnace can be decomposed and burned, converting harmful substances in the tail gas into harmless water, nitrogen and carbon dioxide, realizing environmentally friendly emission of tail gas. This not only complies with national environmental protection policy requirements but also reduces the environmental treatment cost of enterprises.

The wide application of ammonia decomposition hydrogen production technology in multiple industries is not only due to its stable process performance and high-quality gas products but also its significant economic and environmental advantages. In terms of cost, liquid ammonia raw materials are relatively cheap, convenient to transport and store, which can greatly reduce the raw material cost of enterprises compared with gaseous raw materials such as pure hydrogen and pure nitrogen. At the same time, ammonia decomposition hydrogen production equipment has a relatively simple structure, convenient operation and low maintenance cost, making it suitable for large-scale industrial production. In terms of environmental protection, the entire preparation process emits no harmful gases, and the use of hydrogen-nitrogen mixture can also reduce the consumption of oxidizing gases in traditional processes, which is in line with the development trend of industrial green transformation under the "double carbon" goal.

With the continuous upgrading of industrial technology, the requirements of various industries for gas quality, production efficiency and environmental protection level are increasing day by day, and ammonia decomposition hydrogen production technology is also continuously optimizing and upgrading. In the future, through the research and development of high-efficiency catalysts, optimization of equipment structure, and improvement of automatic control level, ammonia decomposition hydrogen production technology will further improve gas purity, reduce energy consumption, expand application scope, play a greater role in emerging fields such as new energy and high-end manufacturing, and provide strong support for the green and efficient development of industrial production.

Brazing of iron/copper/stainless steel

Bright annealing/reduction of pipe fittings

Powder metallurgy sintering

Float glass production line