New technology straw pulp destiny turning

A few years ago, Li Keshi of Shandong and Li Gangrong of Liaoning left home to Beijing to meet with Li Chaowang of Beijing to study a new kind of pulping and papermaking process, oxidation cleaning and pulping. Although jokingly referred to as "the layman of papermaking technology," the three of them have no less enthusiasm and energy devoted to the Paper Materials Technology Research Institute than those of paper-making experts. Now, although this new technology that has just passed the expert certification is still somewhat young, the direction represented by this technology will undoubtedly turn the destiny of the Chinese straw pulp and papermaking industry into a turning point.

Straw Pulp Paper Dilemma

The “grass and wood dispute” has been in China for a long time. People have been hard to decide whether to use straw pulp, paper or wood pulp. As China's wood resources have been relatively scarce, grass pulp, which is relatively abundant in resources and has a very low cost, has once become the main raw material for papermaking in China. However, the unavoidable pollution characteristics of straw pulp and paper technology also made us pay a heavy price for this. .
In the context of almost all papermaking countries in the world adopting wood fiber for papermaking, in 2001, the former State Development Planning Commission, the Ministry of Finance, and the Forestry Bureau jointly issued the “Several Opinions on Accelerating the Construction of Raw Material Forest Bases for Papermaking Industry.” Thus far, The dispute has initially concluded that the integration of forestry and paper has become the mainstream of China's paper industry. At the same time, the country has successively introduced a series of policies and regulations, which has caused the industry's center of gravity to tilt toward pulp and papermaking. Forest-paper integration has finally become an industry-recommended model with policy support and company support.

In sharp contrast with the rapid development of forestry and paper integration, straw pulping and papermaking is quietly exiting.

Li Keshi, who has been working in the paper industry for more than 30 years, is not as simple as grass-pulp and papermaking. Pulp and paper production for him, not only means lingering pollution problems, but also means the county's fiscal revenue of tens of millions of yuan a year, nearly a thousand jobs and farmers are hundreds of yuan per straw sales income.

Li Keshi had long served as a director of a medium-sized paper mill in Shandong. He knew the significance of a paper mill for local finances, employment, and farmers' income. Because it was difficult to overcome the pollution bottleneck, his paper mill was finally forced to close. He told reporters: “The paper industry is indeed a dilemma. Pollution of the environment is a crime for future generations. We all understand that the national requirements require us to understand. However, a (paper) factory means tens of millions of dollars after all. Yuan’s income and the income of nearly a thousand people.”

The experience of Li Keshi is actually the trick of most domestic pulp and paper mills. It is understood that most papermaking enterprises in China, especially small and medium enterprises, still use straw pulp as papermaking raw materials. Although the proportion of straw pulp in China's paper raw material structure is declining year by year, it still accounted for 49% of the share in 2003.

In fact, a large number of grass pulp and paper mills, in a sense, is also determined by China's specific national conditions. As many straw and paper mills are located in the plains of North China, East China, and South China, where forests are lacking but agriculture is well developed, the use of straw has become the most practical and even the only choice; in addition, due to the undeveloped economy in rural areas, Grass pulp and paper mills have relatively simple technology, low investment, sufficient raw materials, large markets, and quick results. They can easily become the major local tax revenue and employment force. It is not an exaggeration to say that “a paper mill can feed a county”. For local economic development, straw pulp mills are indeed an irresistible temptation.

However, the unavoidable pollution problem has become the lifeblood of straw pulp and paper. As we all know, the main source of pollution in China's paper industry today is waste liquids discharged from grass pulping and bleaching projects, especially the strong pollution of grass pulp black liquor (waste liquor produced by grass as raw material pulping process). It has become the "first offender" to destroy the environment. At present, the treatment technology of straw black liquor has become a recognized problem in the world. Especially for small and medium-sized enterprises, straw pulp is used as raw material, and production represents pollution.

Due to the fact that most of the world uses wood pulp to make paper, the current research on grass pulp reduction is mainly concentrated in China. In recent years, there have been some technologies that reduce or even eliminate grass pulp pollution, and have achieved good results, but have not been effectively promoted. The reason is that these technologies mainly deal with the black liquor produced, which is costly and requires a certain scale. This is inconsistent with the low-investment, small-scale characteristics of straw pulp and paper, so it has not been effectively promoted.

In addition, straw pulp paper consumes a lot of water resources during the production process. As China's paper industry is currently concentrating in some regions, and gradually forming a pattern of industrial clusters, it is easy to create water shortages, especially in the northern regions where water is scarce. For example, in Shandong, papermaking industry accounts for about 47% of the province's water consumption. In 2003, water consumption was 430 million cubic meters. To this end, Shandong Province, where water resources account for only one-sixth of the country's per capita possession, has formulated a plan to close all straw pulp mills in the province by around 2005.

So it seems that straw pulping is destined to be unable to escape its fate.

Technical breakthroughs in pulp and paper

As one of the inventors of the "oxidative clean pulping process," Li Chaowang, 49, told reporters that the greatest feature of the invention is pollution-free.

The invention he described is the new technology named "Oxidation Clean Pulp Process", and this technology may become the destiny for the development of straw pulp paper in China.

It is worth mentioning that the inventors of the technology, Li Keshi, Li Gangrong, and Li Chaowang, are self-financing, self-manufactured equipment, and self-developed, and built a demonstration line of 10,000 tons in Shunyi District, Beijing.

During an interview with the production line, the reporter found that compared with the traditional process, the process was different in terms of procedures, and additional processing machinery such as honing machine and electro-oxidation reactor was added. The addition of this process is to avoid contamination at the source of the straw production, which is the most important feature of the technology - no black liquor is produced.

It is understood that the main source of grass pulp pollution is to add lye and chlorine water to the pulp during the bleaching and rinsing process. Although these two strong oxidants have good bleaching effect, on the one hand they need to consume a lot of water to dilute them. On the other hand, black liquor is produced. Due to its great toxicity, even if it is diluted, the impact on the environment will remain great if it is not dealt with in time.

According to Li Chaowang, the key to the "oxidative clean pulping process" is to avoid the addition of alkalis, chlorine, and other chemical auxiliary materials. Instead, it uses a non-polluting oxidant to bleach the pulp, which completely solves the black liquor problem of the pulp slurry. He This process is called "self-oxidation." Due to company secrets and professional knowledge, the reporter could not further understand its reaction mechanism. However, the expert assessment meeting organized by the Science and Technology Department of the State Environmental Protection Administration approved the fact that “Pulping does not produce black liquor”.

On September 14th this year, a review committee, including the experts from the State Environmental Protection Administration, including the academician of the Chinese Academy of Engineering Liu Hongliang and others, reviewed the “oxidative clean pulping process”. The reporter saw from the “accreditation opinion” that the experts We evaluated the process as "chlorine-free, low-pollution, high-yield bleaching process," scientific and innovative, and in line with China's pulp and paper industry, "taking a new-type industrialization path of circular economy, full utilization of resources, and sustainable development," and even Some experts privately praised it as "a technological breakthrough in the paper industry."

In writing, experts focus on the evaluation of new technologies in three ways:

First of all, there is no black liquor in the whole production process and there is basically no pollution. The state's allowable COD (chemical oxygen demand of major pollutants in water) discharge standard is 88 kg/ton of bleached wood pulp and 135 kg/ton of bleached grass pulp, while the COD dissolved amount of new process pulp stock liquid is only 18 kg/ton. After the clarification of the sewage, most of the circulated water is used without any discharge, which controls the discharge of pollutants from the production terminal.

Second, save water, save energy, and save labor. According to China's industrial water quota, it produces 170 tons of water for 1 ton of natural wood pulp, 190 ton for natural grass pulp, 270 to 300 tons for bleached wood pulp, and 360 tons of bleached grass pulp, and only water is used for new process natural wood and straw pulp. Tons of bleached wood and straw pulp only use 10 tons of water, which is only 1/10 of the world's current minimum water consumption (30 tons of water), and the new technology also saves half of the electricity consumption of the old process.

Third, raw materials are extensive. The raw material of “Oxidation Clean Pulping Process” covers all plants with fiber content, including branches and culms that could not be pulped previously, fast-growing forests below 3 years, and corn sorghum stalks. In fact, a wide range of raw materials is itself a major feature of straw pulping. At present, the proportion of straw pulp in China's papermaking raw materials is relatively large.

New technologies still need to be tested

Li Keshi told reporters that as an entrepreneur who has worked in the paper industry for many years, he is very clear that the biggest disadvantage of straw pulp and papermaking compared to wood pulp and paper is pollution and waste, but he is more aware of the relative importance of straw pulp and paper to wood pulp. The advantages of papermaking: low investment, simple process, wide raw materials, and quick results.

He said that China’s forestry resources are still insufficient, and even if a new forestry base is established, it will take years to be effective, and straw pulp and paper use is the most abundant wheatgrass and other weeds in agricultural areas, and it will be effective in that year. "If the peasants want to plant trees, they will have to sell them after seven or eight years to know if they are making a profit or losing money. If it is grass, then it will be good in the coming year." Li Keshi also said that with the link of straw pulp and paper, rural areas can enter into a virtuous circle of raw material cultivation, industrial manufacturing, farmers, and local benefits.

The inventors are quite confident about the prospect of this new technology, but after all, this new technology is still in the experimental stage. Only the trial scale of 10,000 tons can only be called a drop in the ocean. In the paper industry, only the production capacity of over 100,000 tons can be regarded as “scale”, and paper mills under 50,000 tons are classified as “small paper”.

The application of a new process technology to a large-scale production process is by no means a simple mathematical amplification. In the review opinion of the expert review meeting, there are two main points of suggestion for this new technology, that is, industrialized experimental research and improvement of automation, continuous and large-scale production. The inventors also admitted that the application of a production scale of 100,000 tons or more is currently a test for this new technology. Because they are self-funded for research and have limited capabilities, they cannot be as comprehensive as large research institutions and multinational companies. Therefore, they may encounter unforeseen problems in their future practice.

During the interview, the reporter had met with some local government officials and business leaders who had come to seek cooperation after hearing the news. They were optimistic about the application prospect of this technology. For example, Chen Peng, vice chairman of Weinan Luyuan Paper, said that they plan to use the oxidative clean pulping process to establish a 300,000-ton pulp mill in southern Fujian to meet the needs of several nearby paper mills. According to Chen Peng, the pollution-free nature of the new technologies is very attractive. “The main reason is that they (technical) emissions are not polluted, or else if we want to build it, it will not be granted in the province.”

However, there are only 10,000-ton new things in this demonstration capability. Some partners are not without their own concerns. "So look more and discuss with the inventors."