Why is nitrogen plus natural gas used for heating and reduction in the desulfurization tank?

The desulfurization tank uses nitrogen and natural gas for heating and reduction in order to effectively reduce the sulfur compound content. This is because nitrogen and natural gas can provide an appropriate reducing environment that facilitates the reduction of sulfides, converting them into more stable and harmless substances. Specifically, nitrogen and natural gas react with sulfides at high temperatures to produce hydrogen sulfide (H2S) and some other sulfides. These sulfides can be removed or converted through subsequent treatment processes. Since there is no oxygen present in nitrogen and natural gas, this process takes place in an anaerobic environment, preventing sulfides from continuing to oxidize in the presence of oxygen to form harmful substances such as sulfur dioxide (SO2). Furthermore, the principle of using nitrogen and natural gas for heating and reduction is based on thermodynamic equilibrium. By controlling the temperature and atmosphere, the reaction rate and equilibrium position between sulfides, nitrogen, and natural gas can be adjusted to achieve the best desulfurization effect. At the same time, during the heating and reduction process, it is necessary to pay attention to the uniformity of temperature and atmosphere to ensure that the sulfides are fully exposed to the reducing environment, thereby improving the desulfurization efficiency. .

What is the ratio of nitrogen to natural gas? How to make adjustments?

When heating and reducing the desulfurization tank, is its heating temperature determined by the temperature at the outlet of the tank? Should it still be based on the temperature of the desulfurization bed layer?

Once the bed temperature is balanced, the difference from the outlet temperature is small; the outlet temperature should be used as the reference

You are probably referring to the heating process during cold startup of hydrogen production using natural gas, right? The heating of nitrogen usually involves a circulation process for the nitrogen; during this process, the nitrogen returns to the compressor inlet via a return line. Using nitrogen as a medium, heat is transferred to the desulfurization tank, thereby raising its temperature. Once a certain temperature is reached, nitrogen is replaced by natural gas for further heating – at this point, steam is generally required. At the beginning of the heating process, firstly, the system temperature is low, making it unsuitable to introduce steam directly as this would cause condensation; secondly, the amount of steam generated is insufficient, so it is not appropriate to use natural gas for heating.