Recently, the fumaric acid plant of our company has carried out the expansion transformation of waste acid evaporation. Under the condition of certain limitations in the use of existing technology, they have successfully realized the transformation and achieved four outstanding effects of a technology through technological innovation.
Fumaric acid plant mainly deals with the waste acid water produced in the production process of phthalic anhydride plant. It not only reuses the waste acid water, but also solves the environmental protection problem of phthalic anhydride production and produces good economic benefits. However, due to the relatively backward production mode and equipment of fumaric acid plant of the company, in addition to the relatively insufficient production capacity, the treatment of waste acid water produced by phthalic anhydride is not complete, so that the comprehensive potential of the plant has not been brought into full play. Therefore, after repeated research by technicians, it is decided to carry out large-scale expansion and transformation of fumaric acid unit, so as to develop the potential of the unit in environmental protection, energy saving and efficiency creation.
At present, in the process of producing fumaric acid from Phthalic Anhydride washing solution in China, there are biological methods for the treatment of wastewater; Supercritical water oxidation method; The waste water is frozen, filtered and recycled, and then returned to the production process and waste liquid combustion method. Biological wastewater treatment must invest a lot in wastewater treatment plant, and the operation cost is high; It is necessary to purchase a set of expensive equipment to treat wastewater by supercritical water oxidation; The refrigeration, filtration, recovery and treatment of wastewater require the purchase of adsorption tower, ion exchange resin and adsorbent during operation, and the operation cost is also high; The combustion of waste liquid will cause environmental pollution.
In the case of certain limitations in the use of the above methods, the technicians of Harbin Petrochemical Company find another way with innovative ideas. They broke through the conventional method and increased the production capacity of fumaric acid by 50% by adding two crystallization tanks and an automatic unloading centrifuge. The unloading mode was changed from manual shutdown unloading to automatic continuous unloading, which not only greatly improved the work efficiency, but also greatly reduced the labor intensity of operators. Second, a set of cooling return water system is added to improve the evaporation capacity and evaporation efficiency of fumaric acid wastewater. After evaporation treatment, 80% of the waste generated after expansion can be condensed and recycled as make-up water for the water washing system of phthalic anhydride unit, and 20% of the waste residue can be effectively treated by biochemical treatment tank, which completely solves the environmental protection problem in production. After using the backwater, the energy consumption of phthalic anhydride unit is also reduced, and the production cost is significantly reduced. Third, the original field instrument display is changed to the secondary meter display in the main control room, which solves the problem of relatively complex process flow and improves the work efficiency and operation accuracy of employees. Fourth, dust hood, induced draft fan and flapping device are added above the blanking opening of the packaging room; One blower and three induced draft fans are added in the production area. This technical transformation can further prevent dust explosion and pneumoconiosis and improve the working environment of employees.