DODGEN

High-Purity 1,4-Naphthoquinone Purification Project Case

Case Introduction

This project involves a naphthalene purification unit with a planned capacity of 30,000 t/a, adopting DODGEN’s self-developed falling-film crystallization technology and a “4+2-stage dynamic melt crystallization” process. Addressing key industry pain points of traditional distillation—high energy consumption and low separation efficiency—the project successfully achieved efficient upgrading from crude naphthalene to high-purity refined naphthalene (purity ≥99.5%). The unit not only reduces operating energy consumption by 65%–85%, but also increases the overall yield to 91%, establishing a benchmark project featuring low-carbon operation, high purity, and high yield.

Project Background

Industry Demand and Pain Points:Refined naphthalene is a key organic chemical feedstock, widely used in pharmaceuticals, agrochemicals, electronics, and new energy industries. Downstream applications require extremely high product purity, and the market demand for low-energy production processes is increasingly urgent.

Limitations of Conventional Processes:Traditional refined naphthalene production mainly relies on distillation. Since naphthalene and impurities such as indene have similar boiling points, separation is difficult. As higher purity grades are required, the number of theoretical stages in distillation columns increases sharply, causing energy consumption to rise geometrically (accounting for about 60% of total energy consumption in chemical production). In addition, the process faces technical bottlenecks such as low separation efficiency and non-uniform crystal-layer thickness.

Project Positioning:This project is positioned as a core technology upgrade and capacity expansion initiative (based on industry trends, it typically represents advanced technology replacing outdated capacity).

Planned Capacity:30,000 t/a refined naphthalene.

Project Highlights

DODGEN provided end-to-end services for this project, covering process package development, core equipment manufacturing, and engineering implementation. The core value is reflected as follows:

Core Technology Breakthrough:

1 Falling-Film Crystallizer (Core Equipment)

Adopting an innovative swirl film-distribution mechanism, it overcomes the issues of non-uniform crystal-layer thickness and low heat-transfer efficiency associated with conventional natural film distribution. It represents an internationally leading low-carbon separation technology.

2 Dynamic Melt Crystallization Process

Based on the solid–liquid equilibrium principles of the naphthalene–thioindene system, the process adopts a three-stage cyclic operation of “crystallization–sweating–melting”, combined with two stages of static crystallizers for residual liquor recovery. This enables multi-stage, stepwise purification.

Outstanding Performance Metrics:

1 Ultra-high purity

Product purity reaches ≥99.5%, with impurities such as methylnaphthalene controlled at ≤0.5%, far exceeding industry standards.

2 High yield

With a two-stage static mother-liquor recovery technology, the overall yield is increased to 91%, significantly reducing feedstock loss.

3 Maximum energy savings

Compared with conventional distillation, the project reduces energy consumption by 30%, saving about 10,000 tons of standard coal equivalent, and cutting carbon emissions by approximately 25,000 tons.

Chemical Process Solutions

Process Technology

Separation Equipment

Continuous Flow Reactor

Application

Sustainability

Reaction and Separation Professional, Low Carbon Technology Partners

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