The chemical processing industry is one of the largest and most expansive industries that fall under the umbrella of liquid processing. According to the American Chemistry Council, as of July 2021, 96% of all manufactured goods are directly touched by the chemical industry and 25% of the US GDP is supported by chemical manufacturers. Despite the variety of applications the industry influences, chemical processing can be reduced to one goal - take raw materials and facilitate a chemical reaction to convert the raw materials into consumable goods. The final products of chemical processing are used independently or as ingredients in larger chemical recipes. The chemical industry is traditionally broken into three categories of chemical production: commodity chemicals, specialty chemicals, and fine chemicals.
Commodity chemicals are manufactured on a very large scale and are standardized across manufacturers. They are used as ingredients or as a standalone product, like acetone, ethanol or sorbitol. Commodity chemicals are further segmented into organic and inorganic chemicals, defined by the presence of carbon in their chemistry. Examples of organic chemicals are hydrocarbons, phosphorus compounds, and nitrates. Widely used inorganic chemical compounds are water, salts and acids.
Specialty chemicals are uniquely formulated for specific applications and are produced in smaller batches to be used as ingredients or additives across the industry. These chemicals are sold based on their function instead of their composition. Where commodity chemicals provide bulk supplies across the industry, specialty chemicals are produced with one or two core uses. Often used in cosmetic additives, colors and flavors, cleaning materials like detergents, and lubricants, specialty chemicals present a more competitive market within the industry overall.
Lastly, fine chemicals are produced in the smallest but highest dollar value batches. Fine chemicals are isolated or synthesized chemicals that are frequently used in specialty chemical manufacturing. Pharmaceutical manufacturers use fine chemicals as active ingredients in medicine, and food and beverage manufacturing use them in flavoring their products. They require finely tuned processes to acquire purity and are highly specialized to their application.
Because of the breadth of the industry, chemicals are divided into specialty sub-categories based on application.
- Agrochemicals are chemicals that are used in fertilizers, herbicides, fungicides, and soil acidifiers. The agrochemical industry is highly regulated by environmental agencies because of the inherent toxicity of the concentrated ingredients. Bio-based technologies are gaining ground in the agrochemical ecosystem for sustainability and reduced pest resistance over time.
- Petrochemicals are chemicals derived from petroleum (crude oil) and natural gas. These chemicals are critical components for plastics and packing industries, as well as the creation of synthetic rubber commonly used for making tires. Many major brands of consumer and industrial detergents use petrochemicals as surfactants.
- Elastomer is the technical term for the chemical group that makes rubber and rubber-like materials. Elastomers are characterized by the elasticity between the polymer chains that bind the material together. Rubber has many industrial applications and can be tear abrasion resistant and can tolerate high heat and chemical corrosiveness. Commonly used elastomers are silicone, neoprene, nitrile, and polyurethane.
- Polymers are used across the chemical industry but are primarily used in plastic manufacturing. Plastics come in a variety of forms, but can be generalized into two categories: soft and hard plastic. Soft plastics, like the ones used in stretch wrap and plastic bags, are flexible and can soften again if the correct amount of heat is applied. Hard plastics, like the kind used to make PVC piping or molded trim for vehicles, are rigid and cannot be melted back down for reuse. Polyethylene, polystyrene, and polyvinyl chloride are the most commonly used and versatile polymers in the industry.
- Oleochemicals are compounds derived from animal and vegetable fats and oils. As the demand for “green” chemicals grows, oleochemicals are steadily replacing petrochemicals in many formulas in the cosmetics, pharmaceutical, paint and lubricant industries. Oleochemicals are generally safer to use and store, especially in consumer products. They are also renewable and cheaper as the pricing and regulation of crude oil increases. You can find basic oleochemicals in your local grocery store, sold as-is like coconut oil, or as a chemical component like palm oil.
- Aroma chemicals are ingredients that give flavor and fragrance to food, beverages, and personal care products. Depending on the use, they are synthetic and organic chemicals that undergo a chemical reaction to create the final product. Synthetic aroma chemicals are typically cheaper to produce and more consistent compositions. Organic aroma chemicals, like essential oils and other plant derivatives are generally safer but can be less consistent in the reaction process. Commonly used plant based compounds include fragrances and flavors derived from orange blossoms, sandalwood bark, and ginger root. Synthetic aroma chemicals come in various forms of alcohols, ketones and esters.
Chemicals at any level of concentration or volatility can have dramatic and costly effects on processing equipment if not paired with the correct materials. Every part of a processing tank or mixer must be considered when setting up a chemical processing system, from wetted materials to seals and bearings, to motor safety requirements.
For mixing and storage tank fabrication, carbon steel or stainless steel are the most commonly used materials. Carbon steel is extremely durable and a cost effective solution to mixing or storing dry goods. Carbon steel is typically not recommended for wet mixing because it lacks the properties necessary to prevent rust and corrosion over time. Stainless steel comes in numerous levels of quality, or grades. 304 Stainless Steel and 316 Stainless Steel are the two universally used in liquid processing. Both offer superior chemical and heat resistance over carbon steel due to the addition of rust-resistant chromium and, in 316SS, molybdenum for increased chemical resistance.
Mixers and agitators are also highly susceptible to damage by chemical corrosion if not managed correctly. Impellers, shafts and seals are critical to ensuring an effective and safe mixing operation. A shaft and impeller that are affected by chemical corrosion are often weakened and even low shear force can cause catastrophic damage to the mixture, tank and mixer motor if either were to break. Again, as in tank fabrication, 304 stainless steel and 316 stainless steel are excellent, safe and durable options for a shaft and impeller. Mixer seals come in a variety of materials that are rated for specific applications and resistances as well. Chemical mixing seals face different conditions than a standard fluid seal. They must be resistant to chemical attack and premature aging due to the exposure to the mixing chemicals. From a safety perspective, chemical mixing seals must resist leaking to prevent introducing and inducing a chemical reaction with the mixer fluids and mixing materials.
For industries with sanitary requirements like food and beverage, cosmetics and pharmaceuticals, mixing tanks and mixers can be customized to fit the unique regulations of each. Stainless steel tanks can be highly polished to ensure ease of cleaning and reduced transfer of materials from one batch to the next. Impellers and shafts can be welded together and polished to prevent microscopic build-up of leftover materials, or can be coated with non-stick coatings like Teflon. Mixer motors can be cased in stainless steel or coated with white epoxy for washability. Additionally, some chemical mixing applications are highly volatile and require explosion proof motors that are sealed tightly against sparking and igniting vapors from the chemical ingredients. Air motors are also a great hazardous environment solution as they use compressed air systems to rotate the shaft, in place of electric components. Explosion proof electric motors give the user more versatility in controlling speed and batch processes, but air motors are the safest option available by nature of mechanics alone.
Temperature control is another crucial factor in processing chemicals. Most chemical processing requires inducing and sustaining chemical reactions with precision. Heat transferring systems are an effective way to manage temperature of processing liquids, and can be custom designed to manage your specific application needs. Exothermic reactions generate heat that needs to be carried away from the vessel safely. Heating skids do this by running cooled water through a tank jacket and recirculating the warm or hot water away and into piping channels where the water is cooled and continuously recirculated. The same can be done if the temperature of the processing fluids needs to be increased, using heated transfer fluids to warm the vessel to the appropriate temperature.
Chemical mixing poses more challenges than most other fluid mixing, but advancements in technology and engineering have improved the chemical manufacturing process significantly allowing for greater and safer output of the chemicals we use every day. Our engineers are available for your questions or process solutions!