Chemical process diagram is a graphic representation of the chemical production process, and the drawing of chemical process diagram must comply with the "Unified Regulations on Content and Depth of Chemical Process Design and Construction Drawings" (HG 20519) standard. The article pushed by the editor today will include process flow diagrams, equipment layout diagrams, and pipeline layout diagrams. I hope it can be helpful to all chemical process engineers.
1. Process flowchart
A process flowchart is a graphical representation of the chemical production process and all required equipment, pipelines, accessories, and instruments.
According to different stages, the process flow chart includes scheme flow chart and material flow chart in the preliminary design stage, as well as process flow chart with control points, process pipeline and instrument flow chart used in the construction design stage.
1.1 Scheme flowchart
The schematic flowchart is a drawing provided during the preliminary design phase, which unfolds the equipment and process flow lines from left to right according to the order of the equipment and pipeline process flow, drawing a series of equipment graphics and relative position diagrams to express the production overview of the entire factory, workshop or process.
Drawing method of scheme flowchart:
1) The format of the scheme flowchart is generally not specified, and the frame and title bar can be omitted; The preliminary design does not need to add control points or draw according to the legend. Use thin solid lines to draw the equipment schematic diagram in the order of the process, and annotate the equipment name and tag number. Leave a distance between the equipment to draw the process line. Only one set of equipment can be drawn for the same equipment.
2) Draw the main process material flow line with thick solid lines, and draw the flow lines of other auxiliary materials with medium thick solid lines. Arrows indicate the flow direction of materials, and the flow lines are generally drawn horizontally or vertically to avoid excessive back and forth crossing of the flow lines. When the process lines intersect, the latter process line is usually disconnected or bent through.
3) Often using a combination of graphics and tables, accompanied by material flow lines, and marking the names, flow rates, and equipment characteristic data of each material on the flow lines.
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Process plan flowchart
1.2 Material Flow Chart
A material flow chart is a graphical representation that combines graphics and tables to reflect the results of material and energy balance calculations. Describe the main types, flow directions, flow rates, and equipment characteristic data of the main process materials within the boundary area. The material flow chart only adds some technical parameters on the basis of the scheme flow chart.
The process flowchart with control points, also known as the construction flowchart, is a detailed process flowchart drawn on the basis of the scheme flowchart.
1) Content of process flow chart with control points
a. Graphics - schematic diagrams of all equipment and flow lines of various materials should be drawn, as well as symbols for valves, pipeline fittings, instrument control points, etc.
b. Annotation - Detailed annotation of equipment's tag number and name, pipe section number, control points, and necessary explanations.
c. Legend - Provide explanations of the codes, symbols, and other annotations in the diagram, sometimes including indexes of equipment tags.
d. Title bar - annotate the image name, image number, and signature, etc.
2) Drawing method of process flow diagram with control points
a. Drawing and labeling of equipment
① Equipment drawing:
According to the process of the main materials, use a schematic unfolding drawing method to draw from left to right with thin solid lines and specified legends, roughly proportionally.
Common equipment and machine legends are shown in the table below.
Adequate distance should be left between each device to arrange connecting pipelines.
When there are two or more identical systems or backup equipment, only one set should be drawn, and the rest should be represented by a thin double dotted line box, with the system name and number indicated inside the box;
When the process is complex, a separate local system flowchart can be drawn, and the local system can be represented by a thin double dot line box in the overall flowchart.
Common equipment and machine legends
② Equipment labeling
