Dechlorination and Zinc oxide desulfurization reaction

Dechlorination reaction

1.1. Reaction principle

Organic Chlorides Converted to Inorganic Chlorides by Cobalt-Molybdenum Catalyst.It mainly exists in the form of hydrogen chloride, which can react with the alkalinity in the dechlorination agent or the oxide of metal elements with strong affinity with chlorine to form stable metal chlorides and be fixed:

The reaction formula as follows:

MO ＋ nHCl → MCln ＋ H2O

1.2.  Influencing factors

The content of chlorine in the raw material for hydrogen production is small,the influence of temperature and pressure on the reaction is small, and the dechlorination agent is often used together with the hydrodesulfurization agent. Factors such as temperature, pressure, and space velocity have been determined by the hydrodesulfurization reaction system.

Zinc oxide desulfurization reaction

2.1.Reaction principle

The raw material passes through a desulfurizing agent (such as ZnO), zinc oxide can react with hydrogen sulfide.It can convert some simple organic sulfur, and the desulfurization of zinc oxide is relatively fine. At 260-350 ° C, the sulfur content in the raw material can be reduced to 0.5PPm .

The reaction formula as follows:

①　ZnO ＋ H2S → ZnS ＋ H2O

②　ZnO ＋ C2H5SH + H2 → ZnS ＋ C2H6 ＋ H2O

③　COS ＋ ZnO → ZnS ＋ CO2

2.2.Influencing factors

• Temperature

The zinc oxide desulfurization reaction is an endothermic reaction.Increasing the operating temperature is beneficial to the reaction.Especially in the late stage of catalyst use, raising the reaction temperature a little is good for increasing the sulfur capacity and prolonging the replacement cycle.But it cannot exceed 420°C to prevent carbon formation caused by thermal cracking of hydrocarbons.

• Pressure

Increasing the pressure, increasing the partial pressure of sulfide and increasing the contact area between the gas and the desulfurizer, which is beneficial to increase the reaction speed, and is generally used within the range of normal pressure to 4MPa.But at the same time, the volume and utilization of the equipment should also be considered.

• Airspeed

Under the premise of ensuring sufficient linear velocity and no gas film effect, it is beneficial to use a lower space velocity to improve the desulfurization efficiency.General space velocity range: gas space velocity is 1000～2000h-1, liquid space velocity is 1～6h-1.