Source: People's Daily - People's Daily
The picture shows farmers in Suixi County, Huaibei City, Anhui Province recycling straw.
Photo by Wan Shanchao (People’s Vision)
What can a bundle of straw do?
transforms into fibers to weave clothes that are no different from ordinary cotton; transforms into sheets to build beautiful huts with beautiful textures, waterproof and heat insulation; extracts polylactic acid to make degradable plastic bags and disposable tableware...
In recent years, a dazzling array of straw products have increasingly appeared in life. As a country with a large amount of straw resources, how is my country’s straw industrialization progress? What are some good ways to turn straw into treasure? What difficulties still exist in the process of straw utilization? The reporter conducted the interview.
Small straw, multi-purpose
Straw can be processed into fiber raw materials, plates, polylactic acid and other products.
After 7 processes of breaking up, sifting, cutting into sections, splitting, softening, grinding and bagging, a bundle of straw turns into a bag of straw fiber materials and automatically rolls off the production line in sequence. At Jinnong Straw Board Co., Ltd. in Xiayi County, Shangqiu City, Henan Province, straw has completed the first step of raw material conversion. After that, these fiber packages will be transported to processing plants across the country and processed into packaging paper, cartons, disposable lunch boxes...
"Currently, there are three main ways of industrial utilization of straw: as raw materials, as fuel, and as fertilizer." Chen Jiachuan, president of Qilu University of Technology Chen Jiachuan said that making raw materials is one of the ways with higher added value.
How competitive is straw materialization? Especially in the plant fiber market, competition is very fierce. How can straw fiber occupy a place?
Jinnong Straw Board Company General Manager Xu Ming said frankly that in terms of performance, there is not much difference between straw fiber and other plant fibers. However, in the process of converting straw into raw materials, a "treasure" will be produced, which is a magic weapon for enterprises to win.
It turns out that during the processing of straw, a viscous liquid will be produced, from which the formaldehyde-free, green and environmentally friendly adhesive can be extracted. Environmentally friendly boards can be synthesized by mixing the adhesive with waste straw agglomerates, wheat bran, wheat ears, etc. that cannot be made into fibers.
"The boards produced in this way not only do not contain formaldehyde, but also have excellent properties such as high strength, waterproofing, and flame retardancy, and are very popular in the market." Xu Ming said. The emergence of adhesives enables the straw raw material process to achieve 100% comprehensive utilization and zero waste emissions, expands the profit space of enterprises, reduces the cost of straw fiber, and enhances the competitiveness of products.
Straw raw materials have many applications and can be converted into a variety of chemicals for papermaking, textiles, plate processing and chemical raw materials. In recent years, in order to make the straw industry chain truly circular, new technologies and new attempts have continued to emerge.
Straw is "mixed and matched" with construction waste, turning waste into treasure to produce insulating bricks. According to reports, 30% of straw and 70% of construction waste can be made into a new "breathing" wall material through special processes. This kind of brick has thermal insulation and fireproof functions, and is lighter and cheaper than ordinary bricks at the same load-bearing level.
Polylactic acid extracted from straw has entered mass production, which is expected to fill the gap in my country's biodegradable material . Polylactic acid is a new type of polymer material that has all the basic characteristics of general polymer materials, and can also be completely decomposed into carbon dioxide and water under the action of natural microorganisms. "With our current technology, 4 tons of straw can extract 1.3 tons of polylactic acid at a price of 13,000 yuan/ton, which is far lower than the current polylactic acid import price of 20,000 yuan/ton." said Chen Liping, vice president of Anhui Fengyuan Group Co., Ltd.
opens up the transformation process from straw to polylactic acid, and the application scenarios of straw as a raw material are further broadened. In addition to being used as packaging materials and textile fabrics, polylactic acid can also be processed into tissue engineering scaffold materials, fracture internal fixation materials, surgical sutures and other medical supplies.
"Using polylactic acid extracted from straw to spin yarn and make clothes and other textiles, it not only inhibits bacteria and removes mites, but also has flame retardant functions. From raw materials to finished products, the added value increases by more than 10 times." Chen Liping said.
Data from the Ministry of Agriculture and Rural Affairs show that the amount of straw used nationwide in 2019 reached 634 million tons, and the utilization rate has further improved.
Collection, storage and transportation, solving problems
In the recycling process, companies have their own advantages and disadvantages in self-collection and contracting, and transportation and storage are still to be solved.
The industrial utilization of straw is in full swing. Some people have also raised questions. Returning straw to fields has obvious effects of increasing fertilizer and increasing production, and the cost is still low. Why should we promote the industrial utilization of straw?
Regarding this, Chen Jiachuan explained that currently, most places use the mode of crushing straw and returning it directly to the field. However, it takes a long time for straw to rot and mineralize. If the straw is not fully rotted, it is easy to cause additional diseases and insect pests, and may even affect the emergence or growth of seedlings, resulting in reduced crop yields. Another model of "returning the straw to the fields" is to dry and crush the straw to make roughage for dairy cows, and then return the cow dung to the fields as high-quality organic fertilizer. Although "returning the straw to the field" avoids the shortcomings of returning it directly to the field, the number of livestock in my country is limited and cannot fully digest the huge straw production.
According to reports, since the country launched a pilot program for comprehensive utilization of straw in 2016, a development pattern has been basically formed in which fertilizer utilization is the mainstay, feed utilization and fuel utilization are steadily advancing, and raw material utilization and base material utilization are supplemented. Taking Jilin, a province with a large amount of straw, as an example, its straw return utilization rate is about 37% as fertilizer, feed utilization rate is about 18%, energy utilization rate is about 21%, raw material utilization rate is about 2%, and base material utilization rate is about 1%. Chen Jiachuan said that among the five uses of straw, raw material use has the highest added value.
Although the theoretical amount of straw resources produced in my country every year is about 900 million tons, the interviewed companies said that the incomplete collection, storage and transportation system has become a bottleneck restricting the utilization of straw as raw material.
As an agricultural residue resource, the production of straw has a strong seasonality and is closely related to the growth of crops. The unstable supply of straw poses a great challenge to the collection, storage and transportation system, and processing companies have to rack their brains to find solutions.
The recycling link is the first hurdle that companies need to overcome.
"Count mine first, I have more, there are 80 bundles!" On May 10, Jinnong Straw Board Industry Company opened its straw recycling point in Huodian Town, Xiayi County, Henan Province, and was immediately surrounded by villagers.
It turns out that in order to better recycle straw, Xu Ming’s Jinnong Straw Board Industry Company purchased more than a dozen integrated harvesting and baling machines to form a fleet and go to the fields to help farmers harvest grain and recycle straw. After the all-in-one harvesting and bundling machine is turned on, the straw is automatically bundled, with each bundle weighing about 40 kilograms. In order to solve the problem of transporting straw bundles away from the fields, Xu Ming came up with the idea of "paying with points", allowing farmers to take the initiative to send straw to recycling points.
Farmers welcome this method. "It costs 1 yuan per bundle. My tricycle can transport 80 bundles. I can make three trips a day and earn more than 200 yuan!" Villager Guo Dongdong said cheerfully. Xu Ming is also happy, "Companies can recycle straw by themselves, with lower costs, controllable time, and guaranteed quality."
In Lianshui County, Jiangsu , the government department issued a subsidy "gift package" to encourage villagers to start their own businesses and become large purchasers and straw brokers to facilitate the subsequent use and processing of straw.
The autumn harvest is around the corner, and Xu Chunxue, a villager in Biandan Village, Gaogou Town, Lianshui County, is busy overhauling tractors, straw balers and other equipment. "Looking at the crops growing so vigorously in the fields, the amount of straw will definitely be indispensable this year!" The subsidy that had just arrived made him even more energetic. During the "Three Summers" period from last autumn to this year, he purchased and stored a total of 4,230 tons of rice and wheat straw, and received a subsidy of more than 145,000 yuan.
4 years ago, Xu Chunxue opened the Yangkou Zhenglin Straw Processing Factory. During the busy farming season, the factory's straw baling equipment is in constant rotation. The purchase prices of rice straw and wheat straw per ton are 120 yuan and 180 yuan respectively. After compression and packaging, they are sold at a unified price of 240-270 yuan.
China Agricultural University Professor Shi Yuanchun said that the straw broker system can not only free farmers from tedious work such as handling straw, but also help some companies compress their chains and stabilize supply, which is a good attempt.
Transportation and warehousing is another problem that companies need to solve.
Straw is low in price, large in quantity and light in weight. If transported over long distances, the cost will increase and the price advantage will be reduced.In this regard, Shi Yuanchun suggested that all parties in society should jointly establish a multi-level transportation and storage system, establish pre-processing centers in villages and towns where straw is concentrated, and use balers to compress the straw to increase the straw transportation volume of each truck and reduce transportation costs.
At the same time, straw processing companies also need to strengthen refined management capabilities and reasonably control warehousing costs. "Storage of straw is troublesome when the weather is dry and the earth is dry. It is also troublesome when it is windy or rainy. We must prevent fires and moisture." Xu Ming said that unlike the general trend of low inventory in other manufacturing companies, straw processing companies often have high inventories, and reasonable planning is the key.
Judging from current practice, straw processing enterprises still have problems such as small scale and fragmentation. Chen Jiachuan introduced that many straw processing companies often only cover county areas.
Good prospects and great potential
There is still great potential for the utilization of straw as raw material
Looking into the future, there is still great potential for the utilization of straw as raw material.
At present, the technology for extracting polylactic acid from straw has just entered the mass production stage. As a degradable and non-hazardous raw material, polylactic acid has a wide range of application scenarios. At the beginning of the year, the "Opinions on Further Strengthening the Control of Plastic Pollution" was issued, proposing that by the end of 2020, the production and sale of disposable foam plastic tableware and disposable plastic cotton swabs would be prohibited; by the end of 2025, postal express outlets nationwide would ban the use of non-degradable plastic packaging bags, plastic tapes, disposable plastic woven bags, etc. The continuous escalation of the "plastic ban order" has greatly increased the market demand for degradable materials represented by polylactic acid.
"We will launch a straw degradable material production line at the earliest by the end of the year and at the latest in the first half of next year to meet the market's demand for degradable materials." Xu Ming is full of confidence in the new business.
Another industry where straw is expected to show its talents is the paper industry.
Chen Jiachuan said that currently, my country is the world's largest paper producer and consumer, with both production and consumption of paper and cardboard exceeding 100 million tons. For a long time in the past, some companies in our country solved the problem of raw materials for papermaking by importing waste paper and wood chips. With the implementation of waste paper import restrictions, domestic papermaking companies have turned to imported raw materials, and their import dependence has increased to 50%.
Plant fiber made from straw is a very good raw material for papermaking. "Proper utilization of straw as raw material is not only expected to alleviate the shortage of fiber raw materials, but also can use modern biotechnology to replace the traditional high-temperature and high-alkali pulping process, which will help promote the green development of the paper industry." Chen Jiachuan said.
However, Chen Jiachuan also emphasized that although the straw raw material utilization industry is developing rapidly, various regions still need to adapt to local conditions in practice and avoid one-size-fits-all. There are no absolute advantages or disadvantages between using raw materials, fuels, and fertilizers, and adapting measures to local conditions is the key.
"People's Daily" (Page 18, September 30, 2020)
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