How to effectively use straw after it is banned from direct combustion

16/06/2022
biomass straw pellet machine
wood pellet machine manufacturer

High-value utilization of straw is highly valued in China

High-value utilization and resource utilization of straw is an important part of China's carbon peaking action plan in 2030. The successive introduction of national and local policies will accelerate the process of straw industrialization.

Policy background of the straw burning ban and high-value utilization

On October 26, 2021, China's State Council issued the "Carbon Peaking Action Plan before 2030". The circular economy in the "Plan" proposed to help reduce carbon emissions: strengthen the comprehensive utilization of bulk solid waste, and by 2025, bulk solid waste The annual utilization reaches about 4 billion tons. By 2030, the annual utilization will reach about 4.5 billion tons. As an important solid waste resource in rural areas, straw is mentioned in the action to accelerate the high-value utilization of straw, improve the collection, storage, and transportation system, and strictly prohibit burning.

Grain production has increased, and crop straw waste has also greatly increased

China is an important agricultural country in the world, and the output of major food crops and other agricultural and sideline products has maintained a leading global level all year round. In 2021, all localities will consolidate their responsibility for grain production at all levels, implement the strictest arable land protection system, further increase support for grain production, and increase farmers' enthusiasm for growing grain. The country's total grain output reached 1,365.7 billion catties, a record high, an increase of 26.7 billion catties or 2.0% over 2020. In terms of varieties, the production of rice, wheat and corn increased. The output of rice was 425.7 billion catties, an increase of 2 billion catties, or an increase of 0.5%; the output of wheat was 273.9 billion catties, an increase of 5.4 billion catties, or an increase of 2.0%; the output of corn was 545.1 billion catties, an increase of 23.8 billion catties, an increase of 4.6%. China is rich in straw resources, and the amount of collectable resources is relatively high, or it may become the main raw material for bio-manufacturing.

Status Quo of Straw Resource Utilization

In developed countries such as Europe and the United States, as well as China, part of the straw (mainly the roots) is used for fertilizer treatment, and the part above the roots is used for making feed or burning directly. The direct burning of straws pollutes the environment greatly and has been banned at present.The original intention of returning straw to the field as fertilizer is good, but after a long period of practice, the drawbacks of this method have also emerged. Chopped straw is buried in the soil in the fall and then sown. Due to the large gap between the straws, it is difficult for the seeds to directly contact the soil, which greatly affects the germination rate. Moreover, it takes a long time for the straw to be buried in the ground before it can be turned into fertilizer, which is not practical to use.

Moreover, returning the straw to the field is also easy to increase the pests and diseases of the soil. Many egg pathogens are parasitized on the straw, and the eggs also arrive in the field after the straw is returned to the field. The eggs hatch in the soil to give birth to new pests that will harm the growth of crops. Storage and transportation when used as feed is a big problem for people. Straw reuse can also be used as fuel ethanol and to make high-value chemicals, but the initial investment and production costs of these two methods are very high, and they require relatively strict environmental conditions, which are not suitable for most people.

A new way out of straw utilization

Processing straw into compressed pellet fuel is an advanced way of biomass utilization. Ash generated after combustion is an excellent natural fertilizer. At present, biomass "granular" fuel gasification combustion is a clean and environmentally friendly combustion method, which is in line with national conditions and is of great significance for reducing pollutant emissions and protecting the atmospheric environment.

In addition, straw and straw raw materials are made into pellets, which can not only be used as fuel but also be used as feed for cattle and sheep. Making feed pellets largely solves the inconvenience of direct transportation and storage of straw. Making straw into fuel pellets has less up-front investment and production costs than fuel ethanol and chemicals. You just need to find a professional and experienced pellet equipment manufacturer, they will design a biomass pellet production line scheme that meets your use according to your raw material situation and output requirements.

The basic steps of making pellets from straw, forage, etc

Process flow:

1. Rotary cutting and crushing: use a rotary cutting mill to crush the straw to below 8mm;
2. Drying: The crushed materials are dried by a tumble dryer;
3. Granulation: The dried material enters the silo and enters the granulator through the screw dragon.
4. Cooling: high temperature particles enter the cooler for cooling through the conveyor belt;
5. Packaging: The cooled pellets enter the packaging machine for packaging.

The development prospect of straw fuel pellets

Straw fuel pellets are shaped clean fuels that are reprocessed by using agricultural and forestry wastes. There is no pollution when burning and has little impact on the environment. It belongs to sustainable renewable energy - biomass energy. Straw pellet fuel can completely replace coal, although the heat is slightly inferior to coal, but it is better than coal in other aspects.Under the background of China's strong promotion of green, energy-saving and environmentally friendly carbon neutral policies, biomass energy will replace traditional non-renewable resources together with new energy sources such as solar energy, wind energy, and natural gas.