CN106732362A - A kind of kitchen garbage is the sludge base charcoal preparation method of presoma - Google Patents

Abstract

The invention relates to a method for preparing sludge-based biochar using kitchen waste as a precursor. In the invention, the bottom sludge of the municipal sludge is air-dried, put into an oven to dry to constant weight, crushed and ground through a 200-mesh sieve to obtain dry bottom sludge powder. Grind the kitchen waste and adjust it into a paste with a moisture content of 80%, put it in an oven and bake until it reaches a constant weight, crush and grind it through a 200-mesh sieve to obtain a dry kitchen waste powder. Soak the dry sediment powder in 1‑3mol/L KOH, filter the filter residue, put it in an oven at 105°C to dry out the water, take it out and cool it. The sludge dry powder and the kitchen waste dry powder are fully mixed according to the weight ratio of 1-5:1-2 and placed in an atmosphere muffle furnace for pyrolysis to obtain a pyrolysis product. Rinse with hydrochloric acid, soak in deionized water for 20 minutes, filter, repeat 5 times, and then dry to constant weight to obtain sludge-based biochar using kitchen waste as a precursor. The biochar prepared by the invention is applied to the treatment of sewage and waste water, and obtains good economic and environmental benefits.

Description

A preparation method of sludge-based biochar using food waste as a precursor

technical field

The invention relates to a sludge-based biochar, in particular to a method for preparing sludge-based biochar using kitchen waste as a precursor.

Background technique

Biochar refers to the material left after biomass is pyrolyzed at high temperature under anoxic conditions. Biochar has a large specific surface area and porous structure, and has good adsorption performance. It can be used as an adsorbent for sewage treatment to adsorb heavy metals, ammonia nitrogen, phosphate, etc. in water.

Food waste is food residue, which contains a large amount of organic components and presents great environmental risks and hazards. With economic development and improvement of living standards, the amount of kitchen waste is increasing year by year. At present, the volume of kitchen waste in my country has exceeded 20,000 t/d, and it is urgent to find a safe "export".

Food waste contains a large amount of organic matter, which can be used as raw materials for the preparation of biochar. Due to its complex composition, the quality and performance of the biochar produced are far from those of commercial biochar, and its application range and value are also limited.

Activated carbon technology is often used in water treatment, and its high efficiency is recognized by the industry. Sewage or wastewater treatment does not require high-quality activated carbon, so biochar produced from waste containing organic components can be used in the field of sewage (waste) water treatment.

Starting from the idea of "treating waste with waste", the present invention utilizes kitchen waste to prepare biochar, which is applied to sewage (waste) water treatment and achieves good results.

Contents of the invention

The purpose of the present invention is to provide a method for preparing sludge-based biochar using kitchen waste as a precursor. The method is simple, easy to operate, and can achieve the effect of "treating waste with waste".

1. Raw material preparation

The bottom sludge of municipal sludge (moisture content 72-80%) is air-dried under natural conditions, then put into an oven and baked at 105°C to constant weight, remove stones and other sundries, and then crush to 4-8mm, and then grind, pass through A 200-mesh sieve was used to obtain dry bottom mud powder.

Drain the kitchen waste and remove large particles of debris, grind it and adjust it into a paste with a moisture content of 80%, put it in an oven and dry it at 105°C to constant weight, crush it to 4-8mm, grind it, and pass it through a 200-mesh sieve to obtain Food waste dry powder.

2. Preparation steps

(1) Soak the dry powder of the sediment that has passed through a 200-mesh sieve in 1-3mol/L KOH for 8-24 hours, and put the filtered residue into an oven at 105°C to dry out the water until the weight is constant, then take it out and cool it.

(2) Fully mix the dry sludge powder and the dry kitchen waste powder in a ratio of 1 to 5:1 to 2 parts by weight, put the mixed material into an atmosphere muffle furnace for pyrolysis, and inject 100-200mL/min nitrogen gas for 15 minutes, and then Heat to 400-600°C at a heating rate of 10-20°C/min, stay for 2-3 hours, stop heating and cool down to 80°C to discharge, and cool in a desiccator to obtain pyrolysis products.

(3) Rinse the pyrolysis product obtained in step (2) with 1mol/L hydrochloric acid for 5 minutes.

(4) Filter out the hydrochloric acid in step (3), soak the solid matter in deionized water for 20 minutes and then filter, repeat the steps of soaking in deionized water and filtering for 5 times until the pH of the filtrate is 7-8. Then put the supernatant into an oven and dry at 105°C to a constant weight, and finally obtain sludge-based biochar using kitchen waste as a precursor.

The kitchen waste used in the present invention refers to all kitchen residues in hotels, restaurants and canteens.

The advantages of the present invention are:

Starting from the concept of "recycling of waste", a new use of turning waste into treasure has been given to kitchen waste. The biochar made from it is used in sewage (waste) water treatment, and good economic and environmental benefits have been achieved. .

detailed description

Example 1

(1) Air-dry the bottom sludge (moisture content 72%) of municipal sludge under natural conditions, then put it in an oven and dry it at 105°C to constant weight, remove stones and other sundries, and then crush it to 4-8mm, then grind, pass A 200-mesh sieve was used to obtain dry bottom mud powder.

Drain the kitchen waste and remove large particles of debris, grind it and adjust it into a paste with a moisture content of 80%, put it in an oven and dry it at 105°C to constant weight, crush it to 4-8mm, grind it, and pass it through a 200-mesh sieve to obtain Dry food waste powder: Soak the dry food waste powder passed through a 200-mesh sieve in 1mol/L KOH for 24 hours. After filtering, put the filter residue into an oven at 105°C to dry out the water until it reaches a constant weight, then take it out and cool it.

(2) Take 50g of sludge dry powder and kitchen waste dry powder in a ratio of 1:1 by weight and mix them thoroughly, and put the mixed materials into an atmosphere muffle furnace for high-temperature pyrolysis treatment. First pass nitrogen gas at a rate of 200mL/min for 15 minutes, then start heating, increase the temperature at a rate of 10°C/min to 400°C and maintain the temperature for 3 hours, turn off the heating system and let it cool down to 80°C naturally, take out the material and put it in the dryer Cool to get pyrolysis products.

(3) After the pyrolysis product is cooled to room temperature, soak it with 1mol/L hydrochloric acid for 5 minutes.

(4) Filter out the hydrochloric acid, soak the filter residue with deionized water, stir and wash for 15 minutes and then filter, repeat the steps of immersing with deionized water and filtering for 5 times. Finally, put the filtered matter into an oven and dry it at 105° C. to a constant weight, take it out, dry it and cool it, and then obtain the finished sludge-based biochar product described in this embodiment with kitchen waste as a precursor.

Determination of iodine value: the iodine value and specific surface area of the sediment-based biochar prepared by the steps in this example are 489.9 mg/g and 463.7 m ² /g, respectively.

For the treatment of phosphorus-containing wastewater: when the dosage is 1g/L, the biochar prepared in this example can treat phosphorus-containing wastewater in the electromechanical polishing process with a TP concentration of 186mg/L, and the TP concentration in the effluent is 6.51mg/L, and the TP removal The rates were 96.5%.

For leachate pretreatment: When the dosage is 800mg/L, the biochar prepared in this example has the main water quality indicators: COD _Cr concentration 3546mg/L, NH ₄ ⁺ -N concentration 867mg/L, TP concentration 16.7 mg/L landfill leachate pretreatment, the removal rates of the above three indicators were 79.3%, 33.2% and 96.7%, respectively.

The municipal sludge described in this example was taken from a sewage treatment plant in the urban area of Fuzhou City.

Example 2

⑴ Air-dry the bottom sludge (moisture content 78%) of municipal sludge under natural conditions, then put it into an oven and bake it at 105°C until it reaches a constant weight, remove stones and other sundries, and then crush it to 4-8mm, then grind, pass A 200-mesh sieve was used to obtain dry bottom mud powder.

Drain the kitchen waste and remove large particles of debris, grind it and adjust it into a paste with a moisture content of 80%, put it in an oven and dry it at 105°C to constant weight, crush it to 4-8mm, grind it, and pass it through a 200-mesh sieve to obtain Food waste dry powder;

Soak the dry food waste powder passed through a 200-mesh sieve in 2mol/L KOH for 16 hours. After filtering, put the filter residue into an oven at 105°C to dry out the water until it reaches a constant weight, then take it out and cool it.

(2) Take 90g of sludge dry powder and 30g of food waste dry powder in a ratio of 3:1 parts by weight and mix them thoroughly, and put the mixed materials into an atmosphere muffle furnace for high-temperature pyrolysis treatment. First pass nitrogen gas at a rate of 200mL/min for 15 minutes, then start to heat up and heat up to 500°C at a rate of 10°C/min and maintain the temperature for 2.5 hours, turn off the heating system and let it cool down to 80°C naturally, take out the material and put it in the dryer Internal cooling produces high temperature pyrolysis products.

(3) After cooling the high-temperature pyrolysis product to room temperature, soak it with 1mol/L hydrochloric acid for 5 minutes. .

(4) Filter out the hydrochloric acid, soak the filter residue with deionized water, stir and wash for 15 minutes and then filter, repeat the steps of immersing with deionized water and filtering for 5 times. Finally, put the filtered matter into an oven and dry it at 105° C. to a constant weight, take it out, dry it and cool it, and then obtain the finished sludge-based biochar product described in this example with kitchen waste as a precursor.

Determination of iodine value: the iodine value and specific surface area of the sediment-based biochar prepared by the steps in this example are 526.2 mg/g and 503.5 m ² /g, respectively.

For phosphorus-containing wastewater treatment: when the dosage is 1g/L, the biochar prepared in this example can treat phosphorus-containing wastewater in the electromechanical polishing process with a TP concentration of 186mg/L. The TP concentration in the effluent is 5.20mg/L, and the TP removal The rates were 97.2%.

For leachate pretreatment: When the dosage is 800mg/L, the biochar prepared in this example has the main water quality indicators: COD _Cr concentration 3546mg/L, NH ₄ ⁺ -N concentration 867mg/L, TP concentration 16.7 mg/L landfill leachate pretreatment, the removal rates of the above three indicators were 80.2%, 33.4% and 97.1%, respectively.

The municipal sludge described in this example is taken from a sewage treatment plant in the urban area of Fuzhou City.

Example 3

⑴ Air-dry the bottom sludge (moisture content 78%) of municipal sludge under natural conditions, then put it into an oven and bake it at 105°C until it reaches a constant weight, remove stones and other sundries, and then crush it to 4-8mm, then grind, pass A 200-mesh sieve was used to obtain dry bottom mud powder.

Drain the kitchen waste and remove large particles of debris, grind it and adjust it into a paste with a moisture content of 80%, put it in an oven and dry it at 105°C to constant weight, crush it to 4-8mm, grind it, and pass it through a 200-mesh sieve to obtain Food waste dry powder.

Soak the dry food waste powder passed through a 200-mesh sieve in 3mol/L KOH for 8 hours. After filtering, put the filter residue into an oven at 105°C to dry out the water until it reaches a constant weight, then take it out and cool it down.

(2) Fully mix 100g of sludge dry powder and 40g of kitchen waste dry powder in a ratio of 5:2 parts by weight, and put the mixed materials into an atmosphere muffle furnace for high-temperature pyrolysis treatment. First pass nitrogen gas at a rate of 200mL/min for 15 minutes, then start heating, increase the temperature at a rate of 10°C/min to 600°C and maintain the temperature for 2 hours, turn off the heating system and let it cool down to 80°C naturally, take out the material and put it in the dryer cool down.

(3) After the pyrolyzed product is cooled to room temperature, soak it with 1M hydrochloric acid for 5 minutes. .

(4) Filter out the hydrochloric acid, soak the filter residue with deionized water, stir and wash for 15 minutes and then filter, repeat the steps of immersing with deionized water and filtering for 5 times. Finally, put the filtered matter into an oven and dry it at 105° C. to a constant weight, take it out, dry it and cool it down to obtain the finished product of this embodiment.

Determination of iodine value: the iodine value and specific surface area of the sediment-based biochar prepared by the steps in this example are 349.9 mg/g and 362.8 m ² /g, respectively.

For phosphorus-containing wastewater treatment: when the dosage is 1g/L, the biochar prepared in this example can treat phosphorus-containing wastewater in the electromechanical polishing process with a TP concentration of 186mg/L, and the effluent TP concentration is 11.90mg/L, and the TP removal The rates were 93.6%.

For leachate pretreatment: When the dosage is 800mg/L, the biochar prepared in this example has the main water quality indicators: COD _Cr concentration 3546mg/L, NH ₄ ⁺ -N concentration 867mg/L, TP concentration 16.7 mg/L landfill leachate pretreatment, the removal rates of the above three indicators were 73.4%, 30.8% and 90.3% respectively.

The municipal sludge described in this example is taken from a sewage treatment plant in the urban area of Fuzhou City.

Claims (7)

1. A kind of food waste is the preparation method of the sludge-based biochar of precursor, it is characterized in that: 1) Raw material preparation Air-dry the bottom sludge of municipal sludge with a moisture content of 72-80%, put it in an oven at 105°C and bake it to constant weight, crush it to 4-8mm, and then grind it and pass it through a 200-mesh sieve to get dry powder of the bottom sludge; Drain and remove large particles, mince and adjust to a paste with a moisture content of 80%, put it in an oven and dry at 105°C until constant weight, crush to 4-8mm, grind, and pass through a 200-mesh sieve to obtain dry food waste powder ; 2) Preparation steps (1) Soak the dry powder of the sediment that has passed through a 200-mesh sieve in KOH. After filtering, put the filter residue into an oven to dry at 105°C to remove moisture until the weight is constant, then take it out and cool it; (2) Fully mix the dry sludge powder and the dry kitchen waste powder in a ratio of 1-5: 1-2 parts by weight, put the mixed material into an atmosphere muffle furnace for pyrolysis, and cool it in a desiccator to obtain a pyrolysis product . 2. (3) Soak the pyrolysis product obtained in step (2) with 1 mol/L hydrochloric acid for 5 minutes. 3. (4) Filter out the hydrochloric acid in step (3), soak the solid in deionized water for 20 minutes and then filter, repeat the steps of soaking in deionized water and filtering 5 times until the pH of the filtrate is 7-8. 4. Put the supernatant into an oven and dry at 105°C to constant weight, and finally obtain sludge-based biochar using kitchen waste as a precursor. 5. A method for preparing sludge-based biochar with kitchen waste as a precursor according to claim 1, characterized in that said soaking in KOH, the concentration of KOH is 1-3mol/L, soaking for 8-3mol/L 24h. 6. A kind of food waste according to claim 1 is the preparation method of the sludge-based biochar of precursor, it is characterized in that described pyrolysis, at first pass into the nitrogen of 100-200 mL/min 15min, afterwards with Heat up to 400-600°C at a heating rate of 10-20°C/min, stay for 2-3 hours, stop heating and cool down to 80°C to discharge. 7. A kind of food waste is the preparation method of the sludge-based biochar of precursor according to claim 1, it is characterized in that described food waste refers to all food leftovers of hotels, restaurants and canteens.