Chemical engineers solve problems that sit at the intersection of chemistry, physics, and large-scale production. Their core skill is figuring out how to transform raw materials into useful products safely, efficiently, and at massive scale. That work spans dozens of industries, from energy and pharmaceuticals to food and sustainable materials. Here’s a closer look at the specific challenges they tackle.
Scaling Lab Discoveries to Factory Production
One of the most persistent problems in chemical engineering is scale-up: taking a process that works perfectly on a lab bench and making it work in a facility producing thousands of kilograms. The procedures used in a laboratory simply cannot be mimicked on an industrial scale. Mixing behavior changes, heat doesn’t transfer the same way, and reactions that took minutes in a flask may take hours in a massive vessel.
In pharmaceutical manufacturing, roughly 30% of scale-up problems occur during chemical reactions, another 30% involve crystallization (crystals forming too slowly or in the wrong way), and the remaining 40% hit during other processing steps like filtration or drying. Multi-phase mixtures, where solids, liquids, and gases coexist in the same vessel, are especially prone to surprises. A chemist in a lab might solve a “thick” mixture by adding more solvent. An engineer looking at the same problem might redesign the mixing equipment instead, saving materials and time. Chemical engineers bridge that gap between bench-scale chemistry and reliable, repeatable manufacturing.
Internal studies at pharmaceutical companies have found that a significant proportion of processes run at pilot scale produce unforeseen results. The consequences range from minor delays to batches of product that are completely unusable. To manage this, engineers use structured risk assessments that combine a chemist’s knowledge of the chemistry with an engineer’s understanding of how large equipment actually behaves. The goal is to anticipate problems before they cost millions of dollars.
Capturing and Converting Carbon Emissions
Climate change has pushed carbon capture to the top of the chemical engineering agenda. The core challenge is separating CO2 from industrial exhaust streams and either storing it permanently or converting it into something useful. Both paths are riddled with engineering trade-offs.
For capture, engineers design membranes and chemical solvents that pull CO2 out of gas mixtures. The problem is balancing selectivity (grabbing CO2 while letting other gases pass) with permeability (processing enough gas to be practical). Every capture method also carries an “energy penalty,” meaning it takes energy to run the capture system itself. If that penalty is too high, the process costs more than it saves, making it economically pointless. Chemical engineers work to shrink that penalty through better materials and smarter process design.
On the conversion side, researchers are developing pathways that combine electrochemical CO2 reduction with biological processes to turn captured carbon into useful chemicals. Others are trying to convert CO2 into solid carbon products like nanotubes and nanofibers, though significant challenges remain in making those processes reliable at scale.
Making Green Hydrogen Viable
Hydrogen produced from water using renewable electricity, known as green hydrogen, could decarbonize heavy industry and transportation. But chemical engineers face problems at every stage of the value chain.
Production relies on electrolyzers, devices that split water into hydrogen and oxygen. The main types each have drawbacks. PEM electrolyzers are efficient and responsive but depend on expensive catalysts like platinum and iridium. Alkaline electrolyzers are cheaper but slower to react, making them a poor match for the fluctuating output of solar and wind farms. Solid oxide electrolyzers can be highly efficient but operate at extreme temperatures and have durability problems. Engineers are working to develop cheaper catalysts, more durable membranes, and designs that can scale up without ballooning in cost.
Storage is equally tricky. Compressed hydrogen stores well by weight (about 33,000 watt-hours per kilogram) but requires high-pressure tanks that pose safety and leak risks, costing $2.60 to $4.50 per kilogram. Liquid hydrogen holds more energy per liter but must be kept at cryogenic temperatures, and some inevitably boils off during storage, pushing costs to $4.80 to $8.60 per kilogram. Metal hydride storage is safer but far heavier and needs high temperatures to release the hydrogen. Ammonia is cheap to store at $0.50 to $1.50 per kilogram but is toxic and corrosive. Each option presents a different engineering puzzle, and chemical engineers are central to solving them.
Keeping Food Safe and Extending Shelf Life
Chemical engineers design the processing and packaging systems that keep food safe from the factory to your refrigerator. This involves controlling temperature, moisture, oxygen exposure, and microbial growth across supply chains that can span weeks and thousands of miles.
One active area is replacing synthetic preservatives with naturally sourced alternatives. Rose essential oil, for example, has been shown to significantly suppress microbial growth on fruits when applied as a vapor. Algal extracts can improve the quality of chilled fish during storage. These aren’t just chemistry experiments. Turning them into reliable, scalable preservation methods is an engineering problem involving extraction, formulation, and integration into existing food production lines.
Packaging innovation is another frontier. Engineers are developing bio-based films that serve double duty: extending shelf life while also signaling when food has spoiled. One example uses a film made from plant-derived gums embedded with natural dyes from blueberries or beetroot that change color as fish loses freshness. Other engineers focus on optimizing storage conditions. Osmotic dehydration before freezing, for instance, can extend the shelf life of frozen cherry tomatoes by up to 3.5 times compared to standard freezing. Modified atmosphere packaging, which adjusts the gas composition around the product, can dramatically slow spoilage of delicate items like microgreens.
Designing Safer Industrial Processes
Chemical plants handle flammable, toxic, and high-pressure materials every day. Chemical engineers design the safety systems that prevent catastrophic failures and protect both workers and surrounding communities.
Relief systems are a cornerstone of this work. These allow controlled, safe release of hazardous materials through scrubbers or vents rather than risking an uncontrolled rupture of a pressurized vessel. Containment buildings are designed to isolate toxic spills, with automatic or remote controls that let personnel evacuate while the area is continuously monitored. In the most critical applications, like deepwater oil wells, engineers design redundant control systems where independent backup pods can seal a well if all communication, power, and hydraulic connections are lost simultaneously.
Safety isn’t a separate discipline bolted onto a design after the fact. It’s embedded in every stage of process design, from choosing reaction conditions that minimize hazardous byproducts to selecting materials that withstand corrosion over decades of service.
Developing Sustainable Materials
Petroleum-based plastics are cheap and versatile but environmentally damaging, persisting in landfills and oceans for centuries. Chemical engineers are working to replace them with bio-based and biodegradable alternatives that break down naturally after use.
The chemistry of the polymer backbone determines whether a plastic will biodegrade and how quickly. Engineers manipulate chemical structure, bonding, and molecular arrangement to achieve the right balance of durability during use and decomposition after disposal. True biodegradable plastics break down in biologically active environments through the action of bacteria, fungi, and algae, ultimately becoming water, CO2, and organic matter. The engineering challenge is making these materials perform well enough to replace conventional plastics in real applications, from food packaging to agricultural films, while keeping production costs competitive.
Tools Chemical Engineers Use
Modern chemical engineers rely heavily on simulation software to model processes before building them. Tools like Aspen Plus and Aspen HYSYS allow engineers to simulate entire chemical plants on a computer, testing different configurations, temperatures, pressures, and feed compositions without spending a dollar on physical equipment. These platforms support design studies, debottlenecking (finding and fixing the slowest step in a process), control system testing, operator training, and the creation of digital twins that mirror a real plant’s behavior in real time.
Career Outlook
The U.S. Bureau of Labor Statistics reports a median annual salary of $121,860 for chemical engineers as of May 2024. Employment is projected to grow 3% from 2024 to 2034, roughly in line with the average for all occupations, with about 21,600 positions in the field today. The modest growth rate reflects a mature profession, but the breadth of industries that need chemical engineers, from energy and pharmaceuticals to semiconductors and food production, means demand stays steady even as individual sectors shift.