Paper and Pulp Industry

 The paper and pulp business, which has its roots in China and dates back more than 2,000 years, creates the various types of paper used for printing, bags, signage, cardboard, and other things. In 1690, German immigrant William Rittenhouse brought the business to colonial America. Rittenhouse, who came from a line of papermakers, settled close to Philadelphia, constructed a log mill, and started producing paper. The mill was run by the Rittenhouse family until 1820. The first newspaper in Philadelphia, The American Weekly Mercury, was established by Andrew Bradford, a partner in Rittenhouse, and it used Rittenhouse paper.

Evolution

Paper-making has its roots in ancient Egypt, where thin layers of papyrus plant were used to form sheets, and then stacked on top of each other at right angles and pounded together.

The true paper was first created in China, with evidence of the first paper making dating from around the 1st century BC.

Around 1799, the Fourdrinier Machine enabled continuous paper-making for the first time. Until this device, the paper had to be pressed and dried one sheet at a time. Originally developed in England by the French Fourdrinier brothers

The introduction of wood pulp processing in 1843 allowed papermaking to move beyond a reliance on used textile products. Until then, paper mills had resorted to employing “rag-pickers” to comb streets and garbage heaps for scraps that could be processed into paper.

Papermaking process

Steps

1. Trees to logs

2. Log washing and cutting

3. Debarking

4. Metal detection

5. Wood chipper

6. Digester

7. Bleaching

8. Preparation

9. Draining

10. Pressing

11. Drying

12. Calendar

 There are 2 categories of trees used for paper making; softwood trees like pines, larch, eucalyptus, etc; and hardwood trees like birch, hickory, aspen, etc.

Steps 1 and 2

First, the trees are cut into logs, these logs are then washed and cut into smaller sizes.

Step 3

Next, the logs are de-barked. Debarked is a process where the bark of the logs is removed.

Step 4

The debarked logs move through a metal detector to detect metal pieces as they need to be removed.

Step 5

The logs are fed into a wood chipper, where they are cut into small chips.

Step 6

These wood chips move into a digester, where they are boiled in an acid solution to dissolve the lignin and separate the fibres. The pulp that we get after this is woodfree and the fibres are washed to remove the acid solution.

Steps 7 and 8

Next pulp is mixed with bleach and water. Then calcium carbonate and clay are mixed to give the paper a controlled density, and then dyes and optical brighteners are added to improve its appearance.

Step 9

Now the pulp is poured into a drainer machine on a moving belt of fine mesh, and the water is squeezed out.

Step 10

Then the paper moves onto the wet press section, where the paper is pressed by rollers of wood felt.

Step 11

Then the paper is dried and the remaining water is removed in the drier section.

Step 12

The paper finally moves through the calendar section, where the paper is pressed between rollers to give the paper a smooth finish.

Now the paper is ready to be cut and made into different products.