**1. Preface**

Wheat cultivation area is the world's largest agricultural lands, wheat being the most prolific and most widely distributed food crops. At present, the global sum of wheat plant area is of more than 2.2 million ha, with the annual wheat grain output of 730 million tons, accounting for onethird of the world's total food production [1]. Wheat straw is a good fiber material, produced annually in huge quantities worldwide in a much shorter growing cycle than wood. The utilization of no-woody fiber materials to produce cellulosic pulps is the most economically justified solution fitting with the EU's environmental directives, which aim to reduce the consumption of wood fiber in paper and board products and replace it with other plant biomasses [2]. From the production point of view, the world's largest wheat production country is China, followed by India, the United States, and Russia, and these four countries produce 45% of the total world wheat production. Therefore, there are more than 650 million tons of wheat straws available annually [3, 4]. How to utilize these lignocellulosic biomass resources efficiently has been becoming a very urgent issue worldwide [3]. Practically, some countries start to produce electricity by using biomass fuel boilers, and some parts of the world feed straws back to agricultural land by cutting, but most of those resources have not been properly utilized. There are some countries making paper and paperboard products from wheat straw, such as China, Spain, and so on.

**Figure 1.** Baled wheat straw.

**Figure 2.** Cross section of wheat straw [5]. (1) Outer epidermal cells, (2) fibrous tissue band, (3) vessel, (4) bundle sheath,

Wheat Straw Pulping for Paper and Paperboard Production

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(5) vascular bundle, (6) xylem, (7) phloem, (8) parenchyma cell, (9) internal epidermal membrane.

**Figure 3.** Two types of pretreatment processes for wheat straw chip preparation [6, 8].

The term "pulping," in technical processes or methods for production of fibers from cellulosic raw materials, might be classified mainly as chemical pulping, chemi-mechanical pulping, and mechanical pulping processes. The principle of pulping is to separate cellular fibers from plant tissues by chemical cooking to remove lignin or mechanical separation combined with chemical softening, etc.
