With the rapid development of the fine chemical industry, the efficiency and stability of solid and solid-liquid conveying links have become key factors restricting production. In the current era of rising labor costs and the difficulty of manual handling to meet demand, efficient and energy-saving conveying methods and scientific pipeline design have attracted increasing attention from the industry. Recently, industry experts have sorted out key design points for two core conveying methods—pneumatic conveying and crystal slurry conveying—combining practical experience, providing important references for industrial production optimization.
    The power sources for solid conveying mainly include gravity, centrifugal force, pneumatic force, vacuum force, and mechanical force, corresponding to various conveying methods. In terms of energy saving and crystal protection effect, gravity feeding has the most significant advantages, followed by crystal slurry conveying, negative pressure conveying ranks in the middle, and positive pressure conveying is the last due to its high cost and poor effect. This ranking provides an important basis for enterprises to select conveying methods, helping them reduce energy consumption while ensuring product quality.
    As one of the commonly used conveying methods, pneumatic conveying requires attention to multiple details in pipeline design. The pipe diameter is not the thicker the better; it needs to be accurately calculated to ensure that the volume flow rate after gas-solid mixing reaches 12-16 meters per second, avoiding problems such as pipeline knocking and material wall hanging caused by solid retention. Pipeline connections should adopt large arc elbows instead of right-angle tees to ensure smooth conveying; for valve selection, butterfly valves that are prone to pipe blockage should be abandoned and ordinary ball valves should be used; at the same time, air supplement valves should be installed every 3 to 6 meters, and the specific spacing can be flexibly adjusted according to material characteristics. In addition, the gravity feeding pipeline must be larger than the material's angle of repose, and liquid can be used to flush the pipeline once to reduce wall hanging, and vibration hammers with high noise and high damage rate should be avoided as much as possible.
    For crystal slurry conveying, the design of pipeline flow rate is crucial. For aqueous solids with a solid content of less than 60% and a true density of about 2, a flow rate of not less than 0.5 meters per second can effectively prevent material sedimentation. Appropriately increasing the flow rate can improve conveying safety, but the problem of crystal damage must be considered. If the requirements for particles are low, a thinner pipeline can be used to increase the flow rate; the pipeline before the pump should be slightly thinner than the discharge pipeline to avoid material sedimentation when the flow rate is small. It is worth noting that the balance between flow rate and pressure during conveying will affect crystal integrity. When producing finished products with requirements for particle size, small-scale tests are required to determine the optimal parameters, and pure gravity feeding has an absolute advantage in protecting crystal size.
    The design points sorted out this time provide practical solutions for fine chemical enterprises to solve the problems of solid and solid-liquid conveying. Reasonable application of these technical points can not only improve conveying efficiency and reduce production costs but also reduce crystal damage and ensure product quality, promoting the industry to develop in a more efficient and high-quality direction.

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