Identification of the quality of the crystallization kettle

crystallization kettle is based on the core principle of supersaturation control and crystal growth kinetics synergy. By optimizing temperature gradient accuracy, stirring shear force and solution supersaturation, it achieves synergy of crystal particle size distribution, product purity and energy efficiency ratio. It is widely used in fields such as pharmaceutical intermediates, fine chemicals, food additives and electronic materials. In the pharmaceutical industry, it is used for directional crystallization of API; in the chemical industry, it meets the continuous crystallization needs of high-purity inorganic salts; in semiconductor materials, it ensures low metal ion residues in electronic-grade crystals. Compared with traditional reactors, crystallization kettles have the characteristics of high heat transfer efficiency, excellent sealing level and strong process controllability, and are the core equipment for the industrialization of crystallization processes.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide crystallization kettle quality appraisal services. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for crystallization kettle quality appraisal.

With the development of refined crystallization technology, related quality dispute cases have increased significantly. The judicial dispute focuses on:

1, performance index dispute: crystal particle size distribution exceeds standard, product purity is insufficient;

2, material defects: 316L stainless steel Cl⁻ stress corrosion cracking, glass-lined layer resistance to rapid degeneration of temperature difference Performance difference;

3, process problems: dynamic balance deviation of stirring blades, temperature control module response lag;

4, contract performance dispute: key configurations (such as online Raman spectrometer, variable frequency stirring system) are inconsistent with the technical agreement.

The quality identification of the crystallization kettle usually uses the following technical methods:

1. Appearance inspection: Visually inspect the appearance of the crystallization kettle, including whether there are scratches, dents, deformations and other defects.

2. Dimensional measurement: Use measuring tools to measure the key dimensions of the crystallization kettle, including the diameter of the kettle body, the thickness of the bottom of the kettle, the length and width of the stirring blades, etc.

3. Material analysis: Conduct chemical composition analysis on the materials of the crystallization kettle to determine whether the materials meet the design requirements.

4. Performance test: Perform performance test on the crystallization kettle, including temperature control accuracy test, stirring efficiency test and evaporation rate test, etc.

A pharmaceutical company of the applicant signed a "20m³ Crystallization Kettle Purchase Contract" with an equipment manufacturer of the respondent, stipulating that the crystal D90≤30μm. After being put into production, the particle size of the product exceeded 80 μm. The manufacturer argued that it was caused by impurities in the raw materials.

Identification analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of the "Crystalization Kettle", contract technical agreement, on-site investigation case materials and other data, and made the following quality analysis opinions:

involved a design defect in the stirring blades of the crystallization kettle (Reynolds number is only 5×10³), resulting in uneven mixing of the solution; the heat exchange efficiency of the jacket is only 300W/m²·K (protocol ≥500W/m²·K), and the temperature gradient is out of control; the sampling frequency of the online monitoring system is insufficient (1 time/10min), and the supersaturation cannot be controlled in real time.

The appraisal conclusion determined that defects in equipment design and control were the main cause of excessive particle size.

crystallization kettle quality appraisal report should include:

1, appraisal purpose and reference standards;

2, involved specifications, production batch number, construction record;

3, detection method and Equipment list;

4, test data and failure correlation analysis;