On August 4th, the report meeting on high-value utilization of straw under the background of “dual carbon” held in Beijing made the industry focus on high-value straw.

Straw is the other half of agriculture, and the annual production in China exceeds 800 million tons

“In the lifetime of corn, wheat and other crops, the ear growth time only accounts for about 1/4. 40% of its biomass is converted into straw, and 25% to 30% of nitrogen and 20% of phosphorus exist in the straw. It can be said that , the product of agriculture is half the seed and half the straw. The straw is the other half of agriculture worthy of the name.”

According to Yin Chengjie, the former executive vice minister of the Ministry of Agriculture, straw has also become an important agricultural product in the period of accelerated development of modern agriculture. To develop a comprehensive utilization industry of biomass based on straw is to protect arable land, protect the blue sky, and protect the green mountains and clear waters.

“The annual output of straw in my country exceeds 800 million tons. The comprehensive utilization of crop straw can greatly change the low efficiency of agriculture. The quality and efficiency of our country’s agriculture are not very high, and the important reason is that we lose half of it. If we bring back the other half of agriculture, we can really improve economic, social and ecological benefits.” Yin Chengjie said.

Utilization quality needs to be improved urgently, the utilization rate of raw materials is only 1%

At present, the comprehensive utilization rate of straw in my country has reached 87.6%, but from the perspective of utilization structure, direct returning to the field is the main utilization method, and the utilization rate of raw material is only 1%.

Ren Shuben, former director of the Environmental Resources Department of the National Development and Reform Commission, emphasized in his keynote speech that the utilization of straw as a raw material is a new growth point for the development of agro-ecological industries and an important guarantee for the realization of high-value utilization of straw. Converting a steady stream of straw resources into commodities with high added value can effectively realize the industrial-agricultural complex industry, expand the agricultural industry chain, and increase employment opportunities and farmers’ income. Especially in the context of “double carbon”, the production process using straw as raw material has created a new market for enhancing the carbon sink value of enterprises, improving the carbon footprint value for downstream bio-based products, and achieving product carbon reduction and even product carbon neutrality. opportunity.

Polylactic acid and fulvic acid fertilizers become hot spots for high-value utilization methods

Before the report meeting on the high-value utilization of straw under the background of “double carbon” held on August 4, Li Rongjie, chairman of Fengyuan Group, walked into the venue wearing a white shirt and blue pants. He pointed to the clothes on his body and said with a smile: “This one is all made of polylactic acid.”

The use of straw to produce polylactic acid is the long-term tackling direction of Fengyuan. “This is the degradable tableware we supply for the Beijing Winter Olympics and Winter Paralympics. It is made of corn, straw and other biomass raw materials through fermentation and extraction to obtain lactic acid and then polymerized. No microplastics and toxic and harmful gases are produced during the degradation process. is an environmentally friendly material; this pure PLA cutting board is made of straw, the result of photosynthesis of carbon dioxide and water, free from bacteria and aflatoxin; this is the leather we produce, a bio-based polyurethane, its poly Lactic acid polyol and lysine isocyanate are both produced from biological materials, and the next step is to replace the chemical fiber base cloth, and the entire leather can be made of straw, which can replace TDI, MDI…”

In addition to polylactic acid, straw can also be used to produce many high value-added products. Yao Zonglu pointed out that the path of straw high-value technology can be divided into three types: solid state, liquid state and gaseous state according to the properties of the generated products. Through biochar upgrading, enzymatic hydrolysis, saccharification, and fermentation, straw can produce bio-based materials, including carbon-based fertilizers, energy storage materials, polylactic acid, degradable plastic films, fulvic acid fertilizers and other solid products. Straw can produce ethanol, butanol, platform compounds, high-quality fuel oil and other liquid fuels and chemicals through glycolysis, ABE, carbon chain extension, and aqueous biosynthesis. Through dark fermentation, light fermentation, chemical catalysis, etc., straw can produce clean energy such as biological natural gas and hydrogen.

According to Liu Jialei, a researcher at the Institute of Agricultural Environment and Sustainable Development of the Chinese Academy of Agricultural Sciences, “We found in the cotton planting experiment in Shihezi, Xinjiang that the polylactic acid degradable mulch film has the same seedling emergence rate, 20% increase in water retention, and control over traditional polyethylene mulch film. The capacity of weeds is close, and it can already meet the basic requirements of cotton production film mulching, which provides a new direction for the development of agricultural film.” Liu Jialei said.

Yao Zonglu also said that straw can be crushed and homogenized, acid-base softening and tempering, aerobic/anaerobic fermentation and other steps to produce fulvic acid fertilizer, which is widely used in agricultural planting, especially in the fields of fruit, vegetable and flower planting. The annual output of fulvic acid fertilizer in China is about 1.9 million tons, and the demand exceeds the supply. In addition, it is also a future trend to develop the technology to produce fulvic acid fertilizers from the by-products of the sugar-making process of straw technology and realize the high-value conversion of industrial by-products. The 10,000-ton industrial demonstration project of Fengyuan Group using this technology is expected to be put into trial operation in the middle and late August of this year.

“In addition, we are still developing the technology for producing fuel ethanol from straw. my country currently has 800 million to 900 million tons of straw and about 1 billion tons of agricultural and forestry waste. According to Fengyuan’s technical achievements, nearly 2 billion tons of agricultural waste biomass will be used. It can produce 200 million tons of bioenergy and 200 million tons of biomaterials. The full use of the value of straw can not only provide support for oil safety, but also meet the “dual carbon” goal.” Li Rongjie said.