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Chengdu Natural Gas Hydrogen Production Process and Technology

BIG in Small
2022.09.22
read:111second

Hydrogen production from Chengdu natural gas has the advantages of low cost and significant scale effect. The research and development of new technologies for hydrogen production from Chengdu natural gas is an important guarantee to solve the problem of cheap hydrogen sources. As a good and clean industrial energy, natural gas has important strategic significance in China's energy development process. Because natural gas is not only an important fuel for people's daily life, but also a basic raw material for many chemical by-products.

Hydrogen production from natural gas in Chengdu is one of many natural gas products. Liaohe Oilfield, as the third largest oil and gas field in China, has rich natural gas resources, especially oil and gas centralized processing enterprises. In the process of oil and gas production, we can produce a considerable scale. Associated gas dry gas has unique conditions for deep processing of natural gas, which has a wider practical significance for promoting the development and promotion of hydrogen production process from natural gas.

1. Theoretical analysis on the selection of hydrogen production from natural gas in Chengdu

As a secondary chemical product, hydrogen is widely used in medicine, fine chemicals, electronics and electrical industries. In particular, hydrogen, as the fuel of choice for fuel cells, will have a broad market prospect in the field of transportation and power generation in the future, and will play an increasingly important role in the future energy structure. Traditional hydrogen production methods, such as light hydrocarbon steam reforming, water electrolysis, methanol cracking, coal gasification, ammonia decomposition, etc., are relatively mature in technology, but high in cost and productivity. Low labor efficiency and low labor efficiency. In the process of oil and gas production in Liaohe Oilfield, there are associated oil and gas resources such as dry gas and naphtha. Hydrogen production by this method can greatly improve the utilization rate of resources. The main component of associated gas is methane, which uses hydrocarbon steam. It can be converted into hydrogen with high purity and efficiency.

2. Principles of hydrogen production from natural gas in Chengdu

The main processing technologies of natural gas include atmospheric and vacuum distillation, catalytic cracking, catalytic reforming and aromatics production. At the same time, it includes the extraction, collection and purification of natural gas. Under certain pressure, high temperature and catalyst, alkanes react with water vapor in natural gas. The reforming gas is heat exchanged in the boiler and enters the shift furnace to convert CO into H2 and CO2. After heat exchange, condensation and steam water separation, the gas passes through the adsorption tower with three specific adsorbents in sequence through program control, and then through pressure swing adsorption (PSA) to N2, CO, CO, CH4 and CO2. Decompression and desorption release impurities and regenerate adsorbent.

Reaction formula: CH4 H2O → CO 3H2-Q CO H2O → CO2 H2 Q

Main specifications. Pressure: 1.0-2.5MPa; Natural gas unit consumption: 0.5-0.56Nm3/Nm3 hydrogen; Power consumption: 0.8-1.5/Nm3 hydrogen; Scale: 1000 Nm3/h~100000 Nm3/h; Purity: conform to industrial hydrogen, pure hydrogen (GB/T7445-1995); Annual operation time: more than 8000h.

3. Key problems to be solved in hydrogen production from natural gas steam reforming

Natural gas steam reforming hydrogen production needs to absorb a lot of heat, and the hydrogen production process consumes a lot of energy. The fuel cost accounts for 50 to 70 percent of the production cost. Liaohe Oilfield has carried out a lot of fruitful research work in this field and built a large number of industrial production units in oil and gas gathering and transmission enterprises. Considering the application of hydrogen in refineries and future energy fields, the natural gas steam conversion technology cannot meet the requirements. Requirements for large-scale hydrogen production. Therefore, the research and development of new hydrogen production technology from natural gas is an important guarantee to solve the problem of cheap hydrogen source. The new process technology should have obvious breakthroughs in reducing investment in production equipment and production costs.

4. Analysis of new processes and technologies for hydrogen production from natural gas in Chengdu

Hydrogen production from natural gas by adiabatic conversion. The outstanding feature of this technology is that most of the raw material reactions are essentially partial oxidation reactions, and the speed control step becomes a fast partial oxidation reaction, which greatly improves the production capacity of the natural gas hydrogen production unit. The process of adiabatic conversion of natural gas to hydrogen uses cheap air as the oxygen source. The designed reactor with oxygen distributor can solve the hot spot problem of catalyst bed and distribute energy reasonably. Due to the reduction of hot spots in the bed, the reaction stability of the catalytic materials was also obtained. It is greatly improved. In small-scale on-site hydrogen production of hydrogen refueling station, the adiabatic conversion of natural gas to hydrogen can better reflect its strong production capacity. The new process has the advantages of short process flow and simple operation unit, which can significantly reduce the investment in small on-site hydrogen production equipment and hydrogen production cost.

Natural gas is partially oxidized to hydrogen. Compared with the traditional steam reforming method, the process of catalytic partial oxidation of natural gas to synthesis gas consumes less energy and uses very cheap refractory materials to build reactors. Investment and oxygen production cost of air separation unit. The high temperature inorganic ceramic oxygen permeable membrane is used as the natural gas catalytic partial oxidation reactor to simultaneously produce low-cost oxygen and natural gas catalytic partial oxidation hydrogen. The preliminary technical and economic evaluation results show that compared with the conventional production process, the equipment investment can be reduced by 25% to 30%, and the production cost can be reduced by 30% to 50%

High temperature cracking of natural gas for hydrogen production. Hydrogen production by pyrolysis of natural gas is the catalytic decomposition of natural gas into hydrogen and carbon at high temperatures. Because it does not produce carbon dioxide, it is considered as a transitional process between fossil fuels and renewable energy. Liaohe Oilfield has carried out extensive research on hydrogen production from high-temperature catalytic cracking of natural gas, and the carbon produced has specific important uses and broad market prospects.

Hydrogen production from natural gas by autothermal reforming. Compared with reforming process, this process changes from external heating to self heating, and the utilization of reaction heat is more reasonable. Its principle is that exothermic natural gas combustion reaction and strongly endothermic natural gas steam reforming reaction are coupled in the reactor. The reaction system itself can realize self heating. In addition, since the strong exothermic reaction and strong endothermic reaction in the autothermal reforming reactor are carried out step by step, the reactor still needs high temperature resistant stainless steel tubes as the reactor, which makes the autothermal reforming process of natural gas have the disadvantages of high equipment investment and low production capacity.

5. Natural gas desulfurization and hydrogen production technology

On the basis of the original synthetic ammonia production process, Liaohe Oilfield has boldly transformed the reformer, desulfurization conversion, heat recovery system, etc., and adopted innovative devices, which greatly reduced the natural gas consumption compared with the old process. It also decreased by about 1/3. Technical features: After pressurized desulfurization, natural gas is cracked and reformed with steam in a special reformer equipped with catalyst to generate hydrogen, carbon dioxide and carbon monoxide reforming gas. Hydrogen is obtained by pressure swing adsorption (PSA) purification.

Main performance indicators. Under a certain pressure, the refinery uses a composite adsorption bed composed of activated carbon, silica gel, molecular sieve and alumina adsorbent, methanol cracking gas, synthetic ammonia purge gas, catalytic cracking dry gas, shift gas, water gas and semi water gas to selectively adsorb impurity components in various hydrogen containing sources under low pressure, and takes the hydrogen that is difficult to adsorb as the product gas from the adsorption tower

6. Hydrogen separation and purification

The adsorption tower is an alternate process of adsorption, desorption and adsorption preparation to realize continuous hydrogen production. Hydrogen enters the PSA-H2 system under a certain pressure. The rich hydrogen is delivered to the outside world from bottom to top through the adsorption tower with special adsorbent. When the adsorbent in the bed is CO After CH4 removal and N2 saturation, the rich hydrogen is switched to other adsorption towers. During the adsorption desorption process, there is still hydrogen production at a certain pressure in the adsorption tower. This pure hydrogen is used to balance the pressure of other hydrogen just desorbed. The tower is pressure equalized and flushed respectively, which not only makes use of the remaining hydrogen in the adsorption tower, but also slows down the pressure rise speed of the adsorption tower, and also slows down the fatigue of the adsorption tower, effectively realizing the separation of hydrogen and the separation of the combination of hydrogen and impurities.

The above is about Chengdu natural gas hydrogen production process and technology, and I hope it will be helpful to you.


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