When it comes to engineering, the pulp and paper industry is not one that generally springs to mind. Engineers, however, play an essential role in this industry. Without engineers, the industry could not exist, and the world as we know it would change drastically.

What is the pulp and paper industry?

Companies in the pulp and paper industry manufacture pulp, paper, paperboard, and other paper products mainly using wood as a feedstock. Rags, flax, cotton linters, sugar cane residues, and used paper can also be used in the manufacturing process.

Although paper usage has slowed in an increasingly digital world, the industry’s impact on the global economy is enormous. The global pulp and paper market was valued at USD 518.83 billion in 2019 and is expected to reach USD 679.72 billion by 2027.

Paper and paper products are essential in today’s world. Without the pulp and paper industry, there would be no packaging, toilet paper, or books. It is important, therefore, that engineers help keep the industry running.

How does the industry work?

Trees are the first step in the pulp and paper industry. Trees are cut down and debarked before being fed into a chipper. The wood, being made of cellulose fibers, is what will be turned into pulp. Cellulose fibers are held together with a natural glue called lignin, which must be separated from the cellulose so paper can be made. Before pulping, the wood chips must be partially digested with steam to separate the cellulose fibers and to partially dissolve the lignin in a thermomechanical refiner.

Pulping can happen in several different ways, including mechanical pulping, thermo-mechanical pulping, chemi-thermo-mechanical pulping, chemical pulping, and organosolv pulping. 

• With mechanical pulping, wood is ground with grindstones to mechanically separate the fibers from the lignin.  
• In thermo-mechanical pulping, wood chips are preheated with steam under pressure, and a mechanical force is applied to the chips. This method ensures better separation of the fibers and lignin because of the pressurized steam. 
  Chemi-thermo-mechanical pulping involves treating the wood with chemicals and steam before mechanical separation. 
• With chemical pulping, which is the most widely used pulping method for producing high-quality paper, the wood chips are treated with chemicals to remove hemicellulose and lignin while leaving the cellulose fibers intact.
• Organosolv pulping involves using organic solvents to break the wood down into lignin, hemicellulose, and cellulose fibers.

The pulp is then refined to remove excess lignin and hemicellulose and can be bleached to produce light colored or white paper. 

Next, the pulp is diluted. Now in the form of fibers, the pulp is fed to a paper machine, where it is moved onto mesh screens to make a sheet. The water in the pulp is pressed out, and the pulp is dried. The water is then sent to the wastewater treatment section of the process to be treated and disposed of.

The pulp is then run through heated rollers to remove any excess water and to compress it into a roll of paper. After paper is formed, it can be coloured or treated with chemicals to change its properties. It is then cut and shipped to a different facility for further processing.

Any waste produced from the process is treated and disposed of. Some of the pulp is recycled back into the process to eliminate waste. When used paper is used as a feedstock, it is purified and de-inked. This paper is often blended with virgin cellulose fibers from wood chip feedstocks to produce paper more effectively.

How are engineers involved?

As the above conveys, there are a number of processes involved in producing paper. That means that there’s a lot that an engineer is responsible for in the pulp and paper industry. Going through the process again: an engineer would be responsible for maintenance of all equipment in the papermaking process. This could include identifying problematic equipment, developing maintenance schedules, or completing a root cause analysis if equipment breaks down. If one piece of equipment goes down, the papermaking process grinds to a halt. 

Engineers would also be responsible for any equipment used to support the papermaking process but are not directly involved in it, such as chemical tanks. This would include regular maintenance and corrosion management. Choosing the process’ operating parameters is a task for an engineer. These parameters must be chosen to produce as much paper as possible as cheaply and safely as can be done. Such parameters could include pulp flow rate into the process, steam pressure and temperature, roller temperature, chemical concentrations, and recycle loop flow rates.

An engineer could be tasked with making the papermaking process more efficient by increasing production or eliminating wastage. For example, the rollers used to separate the water from the fibers could be heated to a higher temperature so that more water is removed. Process changes could include changes such as using different equipment or recycle loops.

Chemical management is often dealt with by engineers in the pulp and paper industry. Chemicals are used, for example, to treat wood chips and to bleach paper. Engineers must choose the appropriate chemicals to do this. The wrong chemicals can change the paper’s colour, weaken the paper, or make the paper toxic.

Waste treatment is a big part of the pulp and paper industry. The water and chemicals used in the papermaking process must be dealt with somehow. The water is contaminated and must be treated before it can be disposed of. Processes such as clarification, which removes solids, biological treatment, which is used to remove organic matter, and chemical treatment, which is used to eliminate chemicals from the water, are used in water treatment.

An engineer might also be responsible for the design of control systems. These systems are used, for example, to shut down the papermaking process if it goes outside safe operating parameters. These control systems are used to safeguard people and equipment.

What kinds of engineers are involved?

Because of the variety of processes involved in pulp and paper facilities, mechanical engineers, industrial engineers, chemical engineers, process engineers, and electrical engineers are commonly found in the industry. Different tasks in a pulp and paper facility would fall to different engineers.

Is this industry worth pursuing a career in?

It depends on your interests. The pulp and paper industry can certainly provide a challenging, rewarding career. Many pulp and paper facilities are in forested, remote areas, so if you want to be an engineer in this industry you will have to be willing to relocate to a small town. For some this will be a huge incentive; for others not so much.

It’s worth noting that career prospects can be tough. As of May 2019, there were 3,700 engineers employed in the pulp and paper industry in the United States. Although there are always engineers retiring, 3,700 jobs to compete for in a country of 330 million is not a lot.

There has also been a lot of consolidation in the industry. Many smaller facilities have been closed or have been acquired by large companies. This, unfortunately, means fewer jobs for engineers. In May 2019, the mean hourly wage for engineers in the pulp and paper industry was $44.12, and the annual mean wage was $91,770. Although this is a respectable wage, it is not as high as it is in other engineering industries, a factor maybe worth considering.

Signing off

The pulp and paper industry is important in the global economy. It would fall apart without engineers. They are responsible for much of the equipment and processes in this industry. There are opportunities for several engineering disciplines in this industry, and it offers an exciting career for those who choose to join it. Could it be for you?