Industrial production process:
(1) Naphthalene: Naphthalene is solid at normal temperature, and it is necessary to put naphthalene into the naphthalene kettle for heating and melting.
(2) Sulfonation: In the sulfonation process, concentrated sulfuric acid is added to the sulfonation kettle to react with it to produce naphthalenesulfonic acid. There are two types of naphthalenesulfonic acid: α-naphthalenesulfonic acid and β-naphthalenesulfonic acid.
(3) Hydrolysis: Because α-naphthalenesulfonic acid is generated in the sulfonation reaction, its presence is not conducive to the condensation reaction, so water needs to be added to hydrolyze the α-naphthalenesulfonic acid.
(4) Condensation: After the hydrolysis reaction is completed, formaldehyde is added dropwise to the condensation kettle to react with β-naphthalenesulfonic acid to form a naphthalene-based sulfonated formaldehyde condensate.
(5) Neutralization: The material after the condensation enters the neutralization kettle, and the liquid alkali is added dropwise to neutralize the excess sulfuric acid in the sulfonation reaction. When the pH reaches 7-9, stop the dropwise addition.
This control system mainly monitors the production status of four different reaction kettles and their batching tanks. The production line can simultaneously produce 4 channels. Taking production line A as an example, there are one naphthalene kettle and two sulfonation kettles. , Four condensation kettles and one neutralization kettle, each reaction kettle has a feed valve, a discharge valve, an exhaust valve, a heating oil valve, a cooling water valve, a steam pressure valve, a steam flush valve, etc. The kettle is also equipped with a raw material tank, two sulfonation kettles share a sulfuric acid tank, each two condensation kettles are equipped with a set of formaldehyde tanks and dilution water tanks, each condensation kettle has a hydrolysis water tank, the liquid alkali tank is responsible for neutralization Liquid alkali is added dropwise to the kettle, and the specific process flow chart is shown in the figure.