A method for recycling agricultural waste straw

Abstract

The invention discloses a method for recycling waste crop straw. The method comprises the following steps: (1) smashing crop straw, namely cutting the crop straw into sections, and blasting at the pressure of 0.2-2.0MPa for 0.5-1 minute with steam, wherein each section of the crop straw has a length of 3-15cm; (2) fermenting, namely adding ammonia, peptone, bran and chopped peanut shells into the blasted crop straw sections, regulating the molar ratio of carbon to nitrogen (C to N) to 20:30, adding activated sludge from a methane-generating pit, and carrying out solid state fermentation at a temperature of 20-55 DEG C for 10-20 days until combustible gases are generated; and (3) squeezing fermented waste residue to remove part of water, mixing with unfermented smashed crop straw, phosphoric acid or potassium chloride, drying a mixture until water left therein is not more than 10%, molding by extruding, carbonizing, activating with steam, cooling, and smashing to obtain activated carbon, wherein the raw materials molded by extruding contain 90-95% of fermented waste residue, 5-10% of unfermented smashed crop straw, 1-5% of phosphoric acid or potassium chloride and the balance of water, and the crop straw is wheat straw, rice straw, corn straw or soybean straw.

Description

technical field [0001] The invention relates to a method for recycling waste crop stalks. Background technique [0002] my country is a large agricultural country, and the vast rural areas will produce a large amount of plant straw every harvest season. Since most of the young people in rural areas have all moved to the cities to work, there is a shortage of labor, and the workload of plant straw recycling is heavy, and the recycled straw has low reuse value, so they have to be directly burned in the field. Due to the smog caused by burning straw, planes cannot land, highway accidents occur frequently, and air pollution is severe, causing a sharp increase in respiratory diseases. In order to ban the burning of straw, governments at all levels spend a lot of energy every year to strictly investigate the burning of straw. The state invests a lot of money every year to promote straw gasification and straw biogas technology. [0003] There are many existing technologies for p...

AI Technical Summary

Problems solved by technology

First, crop straws and rice husks after processing are burned in large quantities. Although the relevant state departments have banned the burning of straws and chaffs many times, due to the limited use of straws and chaffs in rural areas, there are still a lot of bans. There are still a large number of Straw and chaff are burned, which seriously pollutes the air environment

The second is that untreated poultry manure is discharged into rivers and lakes randomly, causing water pollution and increasing the load of biochemical oxygen demand (BOD), threatening the survival of fish, shellfish and algae; at the same time, agricultural waste pollutes irrigation water, using The ammonia nitrogen and protein nitrogen content in the water are too high, and excessive nitrate is produced in the underground aquifer, which endangers the growth of crops and breeds a large number of flies and other pests, seriously endangering human health

The third is that the excessive use of chemical fertilizers and pesticides in my country's planting industry has caused soil compaction, soil fertility decline, rampant pests and diseases, and agricultural environment pollution.

Usually, wood chips and charcoal are used as the main raw materials, and each ton of activated carbon needs to consume about 4 cubic meters of wood. With the increasing shortage of wood resources, the manufacturing cost of activated carbon continues to increase. In addition, manufacturers in my country use dried potatoes to ferment citric acid every year About 100,000 to 125,000 tons of waste residue is produced, and there is no ideal treatment method at present, causing environmental pollution