Pumps for Chemical and Pharmaceutical Industry: Selection Guide by Material and Fluid Family

1. Centrifugal pump for chemical process: material matrix by family

Material selection for a chemical process centrifugal pump always starts from identification of the fluid family.

There is no universal material: the resistance of the same material changes with concentration, temperature, fluid velocity and impurities such as chlorides. A material suited to an alkaline solution may be attacked by a dilute acid, and austenitic stainless steels may suffer localized corrosion in chloride media.

The matrix below therefore does not recommend material by concentration: it shows what must be confirmed for each family and which options are documented in the FB series. The final choice uses the material manufacturer corrosion tables, tests or plant history.

2. Inorganic and organic acids: critical material boundary

Inorganic acids — sulfuric, hydrochloric, nitric, phosphoric, hydrofluoric — are the most challenging fluids for material selection. Behavior depends strongly on concentration and temperature, and the recommendation can change with a few degrees or a few percentage points of concentration.

Sulfuric acid is the classic example: the behavior of carbon steel, stainless steels and special alloys changes with concentration and temperature — a material acceptable in one range can be attacked quickly in another — and, inside the pump, fluid velocity aggravates erosion-corrosion. Material is therefore chosen not by the acid name but by the real service condition.

Organic acids such as acetic, formic, lactic, citric and oxalic acid also require assessment by concentration, temperature and impurities. The organic or inorganic classification alone does not rank corrosiveness or select the pump material. Provide these data and the history of the material used in the plant to check compatibility under the actual conditions.

3. Volatile organic solvents and classified areas

Pumping volatile solvents — toluene, xylene, hexane, ethyl acetate, isopropyl alcohol — involves two concerns: material compatibility, generally less critical for clean solvents than for acids, and safety in explosive atmospheres.

These solvents have low flash points and form flammable mixtures with air; the area is classified by the project per ABNT NBR IEC 60079-10-1. In Brazil, NR-10 (item 10.9.2) requires conformity assessment of equipment for potentially explosive atmospheres, with compulsory certification of electrical equipment covered by Inmetro Ordinance No. 115/2022.

For the FBCN in solvent service, the points are: wetted-part material (cast iron, carbon steel or CF8M stainless, according to compatibility); an Ex motor suited to the zone, gas group and temperature class of the classification; a coupling guard in non-sparking material, an option in the manual; equipotential grounding; and sealing chosen for containment — for example, a double seal with barrier fluid defined with the seal manufacturer, or seal chamber execution S1, indicated for toxic or aggressive fluids.

FB Bombas quotes the assembly with a motor certified by the motor manufacturer.

4. Polymers, resins and thermal oil loops

Polymer and resin manufacturing involves reactions at elevated temperature, often with viscosity increasing as the polymer forms.

A typical plant has agitated reactors heated by thermal oil, monomer feed lines (often volatile), cooling circuits and product transfer lines to storage.

In this environment, the FB series complement each other: FBCN for low-viscosity monomers and water circuits, with material according to the chemistry; FBE and FBEI for viscous products, selected for the maximum cycle viscosity (FBE: recommended speed per band up to 100,000 SSU; FBEI: independent maximum of 140,000 cP); and FBOT for the reactor thermal oil circuit (series limit: 350 °C). Each point is selected from its own fluid and operating data.

5. Pharmaceutical industry: GMP, ANVISA and the sanitary boundary

In Brazil, ANVISA RDC No. 658/2022 establishes the General Guidelines for Good Manufacturing Practices for Medicines and adopts the PIC/S guidelines as minimum requirements.

For pumps in direct contact with medicines in process, the buyer defines the sanitary requirements — surface finish, absence of crevices, drainability, connections and compatibility with cleaning and sterilization — in its user requirement specification (URS), often referring to bioprocessing equipment standards such as ASME BPE. These requirements are met by dedicated sanitary pumps.

FB Bombas serves the utilities and chemical steps outside the sanitary core — utility water, cooling and heating, transfer of solvents, acids and bases in intermediate synthesis — with FBCN in A743 CF8M stainless among the manual options. Application engineering advises on this boundary case by case and assesses pumping duties using the plant data.