Directions for energy savings and consumption reduction in hydrogen production

Thermal efficiency of the converter； Low water-carbon ratio ； Reuse of acidic water ； Control of exhaust gas temperature

A self-heating conversion process is adopted to reduce heat loss, improve thermal efficiency, lower the water-carbon ratio, and increase the conversion rate

1. In hydrogen production facilities using natural gas (refinery dry gas), the most cost-effective way to reduce energy consumption is to properly control the water-to-carbon ratio； 2. Water-to-carbon ratio: By reducing the amount of steam added (selecting an appropriate ratio based on actual operating conditions), the direct economic benefit is steam savings; indirectly, it leads to less fuel gas needed in the conversion furnace, as well as reduced water consumption due to lower load in the conversion process ； 3. Therefore, it can be seen how important it is to select an appropriate water-carbon ratio to save energy and reduce consumption in hydrogen production facilities. 4. If the water-to-carbon ratio meter gives inaccurate readings, it is necessary to calibrate it. For details on the calibration scheme, please refer to -- Technical Q&A on Hydrogen Production via Hydrocarbon Steam Reforming.

If acidic water is delivered externally, can its residual heat be utilized?

After heat exchange with the boiler feedwater and demineralized water heat exchangers, the residual heat in the medium-temperature steam is already utilized; it is the reuse of acidic water that is the key

At the operational level, consideration can only be given from two aspects: one is the design of the conversion furnace, and how to improve its efficiency； The second is the consideration of catalyst performance, such as how to improve catalyst activity and selectivity, etc.

The temperature after the medium-temperature reactor can be utilized for waste heat recovery.

It can be considered from various aspects: improving the thermal efficiency of the converter (reducing the oxygen content in the flue gases and the flue gas temperature)； Increase conversion rate ； Reduce water-carbon ratio ； Increase the reuse rate of acidic water ； Increase the hydrogen recovery rate of PSA products ； Adjust the water circulation volume of the water cooler in a timely manner to maintain an appropriate temperature difference between the inlet and outlet water temperatures ； Add variable-frequency equipment ； Reduce unnecessary venting ； Optimizing raw material quality and operating parameters to extend the catalyst’s service life, etc.

The converter is a major energy consumer in the plant, so efforts should be focused on it. The optimization of the water-to-carbon ratio mentioned above is a very good approach; for example, by increasing online analysis of the feed material, it is possible to calculate the required steam amount based on the carbon atoms in the feed ； There is also combustion optimization; for example, the stoves designed by DeShinib feature control of the heat value of combustion, which enables good regulation of the fuel-to-air ratio and maintains the oxygen content in the flue gases at 2%. Some new technologies are applied, such as automatic control systems for feeding and loading, to balance the feed and the product and avoid losses due to product discharge ； Increase pre-conversion, raise the inlet temperature of the converter, and reduce the thermal load on the converter, etc. There is also the need to maximize the production capacity of the equipment and improve its asset efficiency, and so on.