Primary reformer in the chemical industry
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| Primary reformer in ammonia plant |
Hi, chemical engineering friends, this time we
will discuss a quite interesting topic, especially for friends who are
very interested in the petrochemical or fertilizer fields. Yes, the
picture above shows the fertilizer industry process equipment that we will
discuss, commonly referred to as the primary reformer. What is a primary
reformer, to find out we need to get acquainted with the "black
furnace" on this one.
The primary reformer is one of the important
chemical industry process units used to produce synthesis gas.
The synthesis gases formed are the main raw materials for the production of
ammonia, methanol, hydrogen, and various other chemical products. Synthesis gas
can be produced through reforming by reacting natural gas using steam (water
vapor) under certain operating conditions.
In the beginning, we called the primary
reformer a "black furnace". This is because the working mechanism of
the primary reformer is the same as the working principle of the furnace. Let's
say the furnace that is being used to cook rice. The furnace is used as a
medium for the combustion process. Firewood is used as fuel to generate heat so
that the rice can cook or mature perfectly. Similarly, the primary reformer is
the medium for the combustion reaction to take place. The heat required for the
reforming process to take place is generated from the combustion reaction
between combustion air and fuel.
Before using natural gas as a raw material,
impurities are removed from the gas. Impurities that are usually contained in
natural gas are sulfur (S) in the form of inorganic compounds (H2S)
and organic sulfur (RSR), mercury (Hg), and carbon dioxide (CO2).
Impuritis-free natural gas is reacted with steam (water vapor) to produce H2
and CO2 gas. Then the natural gas and process steam are fed to the
Primary Reformer through catalyzed tubes. In the catalyzed tubes the natural
gas, which contains mainly methane, reacts with steam to form H2, CO, and CO2.
Meanwhile, heavy hydrocarbons are converted to methane.
The following reactions occur in the primary reformer:
1.
Combustion reaction:
CH4 + 2O2 à CO2 + 2H2O + Q
2. Conversion reaction of heavy hydrocarbons to methane:
HC + 2H2O à CH4 + CO2
3. Main reaction (reforming)
CH4 + H2O à CO + 3H2 (methane
- steam reaction, endothermic)
CO + H2O à CO + H2 (shift reaction, exothermic)
The total (net) synthesis gas formation
reaction is endothermic and takes place at a temperature of 780-820oC
and a pressure of 37.19Kg/cm2G with steam to carbon ratio (S/C) of
3.2 mol/mol, with a nickel base reforming catalyst.
The production of synthesis gas using a
primary reformer is a complex process that requires close monitoring and
control. Failure to manage the primary reformer unit can cause disruptions in
the production of synthesis gas and can affect the availability and quality of
the chemical products produced. Therefore, it is important to have a good
understanding of the synthesis gas production process and primary reformer
management.