Method for returning straw to field through pyrolysis

Abstract

A straw pyrolysis returning method comprises the following steps: preparing a carbonization furnace, then adding crushed straw into the carbonization furnace for heating treatment, then putting the heated material into a water-cooling deslagging device for water-cooling deslagging treatment, and leaving returning solid matters obtained by the water-cooling deslagging treatment; introducing the gas generated by heat treatment pyrolysis into a condenser for condensation treatment, separating and leaving condensed liquid therein, introducing the condensed liquid into a filter tank, and filtering to obtain returning liquid; scattering the returning solid matter and the returning liquid which are not used as the filter material into the farmland for returning to the field. The purpose of the invention is to provide a method capable of reducing straw in an extremely short time, avoiding accumulation of incomplete decomposition of straw in a field, completely killing sick eggs in the straw, and converting the sick eggs into an organic fertilizer and a soil conditioner in an extremely short time in a pyrolysis manner so as to improve the quality of soil and increase the fertility of the field. And meanwhile, the pollution of straw incineration to the environment is reduced.

Description

Technical Field

[0001] The invention relates to a method for returning straw to fields by pyrolysis. Background Art

[0002] Burning of straw and returning it to the fields will cause serious pollution to the environment. For this reason, the straw produced in large quantities every year is usually dealt with by crushing it and returning it directly to the fields.

[0003] Studies have found that after straw is crushed and returned to the field, the decomposition process in the soil can be divided into three stages: initial decomposition stage, mid-term decomposition stage and stable decomposition stage.

[0004] Initial decomposition stage: In the initial decomposition stage, the easily decomposable organic matter in the straw will be quickly decomposed, mainly by microorganisms and other decomposers in the soil. This stage usually lasts from a few months to about a year, depending on factors such as soil temperature, humidity and microbial activity. The amount of straw residue in the initial decomposition stage is relatively high, usually around 30%-50%.

[0005] Mid-term decomposition stage: After the initial decomposition stage, the decomposition speed will gradually slow down. At this time, the hard-to-decompose organic matter in the straw begins to be decomposed, and it takes a long time for these organic matter to be completely decomposed. The mid-term decomposition stage usually lasts from a few years to more than ten years, and the specific time also depends on the soil conditions and the nature of the straw. The amount of straw residue in the mid-term decomposition stage will be slightly lower than that in the initial decomposition stage, usually around 20%-40%.

[0006] Stable decomposition stage: After the mid-term decomposition stage, most of the organic matter in the straw has been decomposed, leaving only a small part of the difficult-to-decompose material. The decomposition rate in the stable decomposition stage is very slow, and it may take decades or even longer to be completely decomposed. After the stable decomposition stage is completed, the amount of straw residue is low, usually below 10%.

[0007] The specific time for straw to decompose after it is returned to the field depends on many factors, including soil conditions, climate conditions, the nature of the straw, and the activity of microorganisms in the soil. However, it is generally believed that long-term and large-scale straw return to the field will cause incomplete straw decomposition and gradual accumulation, thus bringing negative impacts on soil and crop growth and yield. The main points include the following:

[0008] 1. Nitrogen competition: The carbon and nitrogen content in straw is relatively high, and the decomposition process will consume nitrogen in the soil, resulting in insufficient nitrogen absorption by crops, affecting crop growth and yield.

[0009] 2. Acidification effect: Returning too much straw to the field will increase the acidity of the soil, lower the pH value of the soil, affect the biological activity and nutrient supply of the soil, and thus affect the growth and yield of crops.

[0010] 3. Transmission of pests and diseases: There may be pathogens and insect eggs in the straw. If it is directly returned to the field, it is easy to spread pests and diseases, causing crops to be attacked by pests and diseases and reducing crop yields.

[0011] 4. Decrease in crop quality: Returning too much straw to the fields may lead to an increase in the ash content in crops, affecting the quality of crops, especially grain crops.

[0012] From the above analysis, it can be seen that the problems caused by excessive return of straw to the fields have made it difficult to return the straw directly to the fields after crushing it. How to return the straw to the fields more scientifically has become a difficult problem that needs to be solved urgently in the field of straw treatment. Summary of the invention

[0013] The purpose of the present invention is to provide a straw pyrolysis and field return method that can reduce the amount of straw in a very short time, avoid the accumulation of incomplete decomposition of straw in the field, and completely kill the diseased and insect eggs in the straw, so as to make full use of the straw resources in the farmland and convert them into organic fertilizer and soil conditioner in a very short time by pyrolysis to improve the quality of the soil and increase the fertility of the farmland, while reducing the pollution of the burning of straw to the environment.

[0014] The straw pyrolysis and field returning method of the present invention comprises the following steps:

[0015] A. Crush the straw to be returned to the field to less than 15 mm;

[0016] B. measuring the moisture content of the chopped straw, and drying the chopped straw whose weight percentage of moisture content is greater than 25% to make the weight percentage of moisture content of the chopped straw less than 25%;

[0017] C. Prepare a carbonization furnace, preheat the carbonization furnace to 300°C-500°C, then add chopped straw with a water content of less than 25% by weight into the carbonization furnace for heating treatment for 15-25 minutes, then put the heated material into a water-cooled slag discharger for water-cooled slag discharge treatment, leaving the solid matter returned to the field obtained by the water-cooled slag discharge treatment;

[0018] D. introducing the gas generated by the pyrolysis during the heating treatment into a condenser for condensation treatment, separating and retaining the condensed liquid therein, introducing the condensed liquid into a filter tank, using a portion of the returned solid matter obtained in step C as a filter material in the filter tank to filter the condensed liquid, and obtaining the returned liquid after filtering treatment;

[0019] The remaining gas generated by the pyrolysis during the heating process is introduced into the main furnace through the induced draft fan as fuel to heat the main furnace. The flue gas after combustion is discharged after dust removal, desulfurization and denitrification treatment.

[0020] E. The solid matter and liquid returned to the field that have not been used as filter media are spread on the farmland for return to the field treatment, and the solid matter used as filter media is used as raw material for making machine-made charcoal.

[0021] Preferably, in step A, the straw to be returned to the field is crushed to less than 10 mm; in step B, the weight percentage of water content in the crushed straw is made less than 20%; in step C, the carbonization furnace is preheated to 350°C-450°C.

[0022] Preferably, in step A, the straw to be returned to the field is crushed to less than 5 mm; in step B, the weight percentage of water content in the crushed straw is made less than 15%; in step C, the carbonization furnace is preheated to 380°C-420°C.

[0023] Preferably, the equipment for drying and processing the chopped straw, the carbonization furnace, the water-cooled slag discharger, the condenser and the dust removal, desulfurization and denitrification equipment for processing the flue gas after combustion are all integrated and installed on a straw returning vehicle that can travel in the farmland. The straw returning vehicle is provided with a hopper, and the straw returning vehicle is provided with a hopper that can be connected to the outlet of the combine harvester for processing the straw, and receive the processed straw recovered by the combine harvester.

[0024] The straw pyrolysis and returning method for returning to the field of the present invention comprises the following steps: preheating a carbonization furnace to 300-500°C, adding chopped straw with a water content of less than 25% by weight into the carbonization furnace for heating treatment for 15-25 minutes, preheating the carbonization furnace to 300-500°C, adding chopped straw with a water content of less than 25% by weight into the carbonization furnace for heating treatment for 15-25 minutes, and then placing the heated materials into a water-cooled slag discharger for water-cooled slag discharge treatment, leaving the returned solid materials obtained by the water-cooled slag discharge treatment; and placing the heated pyrolysis materials into a water-cooled slag discharger for water-cooled slag discharge treatment. The generated gas is introduced into a condenser for condensation treatment, and the condensed liquid is separated and left therein, and the condensed liquid is introduced into a filter tank, and a part of the returned solid matter is used as a filter material in the filter tank to filter the condensed liquid, and the returned liquid is obtained after filtering treatment; the remaining gas generated by the heating treatment pyrolysis is introduced into the main furnace through an induced draft fan as a fuel to heat the main furnace, and the flue gas after combustion is discharged after dust removal, desulfurization, and denitrification treatment; the returned solid matter and the returned liquid that are not used as filter material are spread into the farmland for returning treatment, and the solid matter used as filter material is used as a raw material for manufacturing machine-made charcoal. Due to the above-mentioned unique technical features of the present invention, the straw pyrolysis and field return method of the present invention has the characteristics of being able to reduce the amount of straw in a very short time, avoiding the accumulation of incomplete decomposition of straw in the field, and completely killing the diseased and insect eggs in the straw, and can make full use of the straw resources in the farmland, and convert it into organic fertilizer and soil conditioner in a very short time through pyrolysis to improve the quality of the soil, increase the fertility of the farmland, and reduce the pollution of the environment caused by the burning of straw.

[0025] Other details and features of the straw pyrolysis and field return method of the present invention can be clearly understood by reading the embodiments described in detail below. DETAILED DESCRIPTION

[0026] The present invention produces high-quality wood vinegar by treating the condensate of the charcoal carbonization furnace by using a membrane processor process, a micro-nano flotation process, a carbon powder and an activated carbon oscillation adsorption process, and uses the carbon powder of the charcoal residue produced by the carbonization furnace as a raw material for rapid treatment of the condensate of the carbonization furnace, and can use the charcoal powder adsorbed with tar and wood vinegar as a charcoal fertilizer for the production of soil conditioners. The condensate of the carbonization furnace can be directly and rapidly treated without using a large number of liquid storage tanks to statically separate the condensate of the carbonization furnace. The condensate of the carbonization furnace can be processed once to produce high-quality wood vinegar. Therefore, the present invention is particularly suitable for using the wood vinegar produced in the production of charcoal to produce a variety of series of products, improve the quality of wood vinegar, and upgrade existing production equipment.

[0027] The straw pyrolysis and field returning method of the present invention comprises the following steps:

[0028] A. Crush the straw to be returned to the field to less than 15 mm;

[0029] B. measuring the moisture content of the chopped straw, and drying the chopped straw whose weight percentage of moisture content is greater than 25% to make the weight percentage of moisture content of the chopped straw less than 25%;

[0030] C. Prepare a carbonization furnace, preheat the carbonization furnace to 300°C-500°C, then add chopped straw with a water content of less than 25% by weight into the carbonization furnace for heating treatment for 15-25 minutes, then put the heated material into a water-cooled slag discharger for water-cooled slag discharge treatment, leaving the solid matter returned to the field obtained by the water-cooled slag discharge treatment;

[0031] D. introducing the gas generated by the pyrolysis during the heating treatment into a condenser for condensation treatment, separating and retaining the condensed liquid therein, introducing the condensed liquid into a filter tank, using a portion of the returned solid matter obtained in step C as a filter material in the filter tank to filter the condensed liquid, and obtaining the returned liquid after filtering treatment;

[0032] The remaining gas generated by the pyrolysis during the heating process is introduced into the main furnace through the induced draft fan as fuel to heat the main furnace. The flue gas after combustion is discharged after dust removal, desulfurization and denitrification treatment.

[0033] E. The solid matter and liquid returned to the field that have not been used as filter media are spread on the farmland for return to the field treatment, and the solid matter used as filter media is used as raw material for making machine-made charcoal.

[0034] As a further improvement of the present invention, in the above step A, the straw to be returned to the field is crushed to less than 10 mm; in the step B, the weight percentage of water content in the crushed straw is made less than 20%; in the step C, the carbonization furnace is preheated to 350°C-450°C.

[0035] As a further improvement of the present invention, in the above step A, the straw to be returned to the field is crushed to less than 5 mm; in the step B, the weight percentage of water content in the crushed straw is made less than 15%; in the step C, the carbonization furnace is preheated to 380°C-420°C.

[0036] As a further improvement of the present invention, the above-mentioned equipment for drying and processing chopped straw, carbonization furnace, water-cooled slag discharger, condenser and dust removal, desulfurization and denitrification equipment for processing post-combustion flue gas are all integrated and installed on a straw returning vehicle that can travel in farmland. The straw returning vehicle is provided with a hopper. The straw returning vehicle is provided with a hopper that can be connected to the outlet of a combine harvester for processing straw, and receive the processed straw recovered by the combine harvester.

[0037] The equipment for drying and processing chopped straw, carbonization furnace, water-cooled slag discharger, condenser and dust removal, desulfurization and denitrification equipment for processing post-combustion flue gas are all integrated and installed on a straw return vehicle that can travel in the farmland. Combined with the existing combine harvester, the straw recovery and crushing can be carried out simultaneously, which can greatly improve the efficiency of straw pyrolysis and return to the field.

[0038] The straw pyrolysis and returning method for returning to the field of the present invention comprises the following steps: preheating a carbonization furnace to 300°C-500°C, adding chopped straw with a water content of less than 25% by weight into the carbonization furnace for heating treatment for 15-25 minutes, preheating the carbonization furnace to 300°C-500°C, adding chopped straw with a water content of less than 25% by weight into the carbonization furnace for heating treatment for 15-25 minutes, and then placing the heated materials into a water-cooled slag discharger for water-cooled slag discharge treatment, leaving the returned solid materials obtained by the water-cooled slag discharge treatment; and removing the heat-treated materials from the carbonization furnace; The gas is introduced into a condenser for condensation treatment, and the condensed liquid therein is separated and retained. The condensed liquid is introduced into a filter tank, and a part of the returned solid matter obtained in step C is used as filter material in the filter tank to filter the condensed liquid, and the returned liquid is obtained after filtering; the remaining gas generated by the heating treatment and pyrolysis is introduced into the main furnace through an induced draft fan to be used as fuel to heat the main furnace, and the flue gas after combustion is discharged after dust removal, desulfurization, and denitrification treatment; the returned solid matter and returned liquid that are not used as filter material are spread on the farmland for returning treatment, and the solid matter used as filter material is used as a raw material for manufacturing machine-made charcoal. Due to the above-mentioned unique technical features of the present invention, the straw pyrolysis and field return method of the present invention can reduce the amount of straw in a very short time, avoid the accumulation of incomplete decomposition of straw in the field, and completely kill the diseased and insect eggs in the straw. It can make full use of the straw resources in the farmland and convert them into organic fertilizers and soil conditioners in a very short time through pyrolysis to improve the quality of the soil, increase the fertility of the farmland, and at the same time reduce the pollution to the environment caused by the burning of straw.

[0039] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineers and technicians in the field should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for returning straw to the field by pyrolysis, characterized in that The steps include: A. Crush the straw to be returned to the field to less than 15 mm; B. measuring the moisture content of the chopped straw, and drying the chopped straw whose weight percentage of moisture content is greater than 25% to make the weight percentage of moisture content of the chopped straw less than 25%; C. Prepare a carbonization furnace, preheat the carbonization furnace to 300°C-500°C, then add chopped straw with a water content of less than 25% by weight into the carbonization furnace for heating treatment for 15-25 minutes, then put the heated material into a water-cooled slag discharger for water-cooled slag discharge treatment, leaving the solid matter returned to the field obtained by the water-cooled slag discharge treatment; D. introducing the gas generated by the pyrolysis during the heating treatment into a condenser for condensation treatment, separating and retaining the condensed liquid therein, introducing the condensed liquid into a filter tank, using a portion of the returned solid matter obtained in step C as a filter material in the filter tank to filter the condensed liquid, and obtaining the returned liquid after filtering treatment; The remaining gas generated by the pyrolysis during the heating process is introduced into the main furnace through the induced draft fan as fuel to heat the main furnace. The flue gas after combustion is discharged after dust removal, desulfurization and denitrification treatment. E. The solid matter and liquid returned to the field that have not been used as filter media are spread on the farmland for return to the field treatment, and the solid matter used as filter media is used as raw material for making machine-made charcoal.

2. The method for returning straw to the field by pyrolysis according to claim 1, characterized in that In the step A, the straw to be returned to the field is crushed to less than 10 mm; in the step B, the weight percentage of the water content of the crushed straw is made less than 20%; in the step C, the carbonization furnace is preheated to 350°C-450°C.

3. The method for returning straw to the field by pyrolysis according to claim 2, characterized in that In the step A, the straw to be returned to the field is crushed to less than 5 mm; in the step B, the weight percentage of the water content of the crushed straw is made less than 15%; in the step C, the carbonization furnace is preheated to 380° C.-420° C.

4. The method for returning straw to the field by pyrolysis according to claim 1, 2 or 3, characterized in that The equipment for drying and processing the chopped straw, the carbonization furnace, the water-cooled slag discharger, the condenser and the dust removal, desulfurization and denitrification equipment for processing the flue gas after combustion are all integrated and installed on a straw returning vehicle that can travel in the farmland. The straw returning vehicle is provided with a hopper. The straw returning vehicle is provided with a hopper that can be connected to the outlet of the combine harvester for processing straw and receive the processed straw recovered by the combine harvester.