CN106995708A - A kind of biomass charcoal making system and method - Google Patents

Abstract

The invention discloses a biomass charcoal production system and method. The system includes a biomass feeder, a carbonization furnace, a cyclone separator, a combustion furnace, an air preheater, a bag filter, an induced draft fan, a chimney, a blower, a circulation fan, Start the combustion chamber; the pyrolysis gas exhausted from the carbonization furnace undergoes gas-solid separation in the cyclone separator and then discharges from the separator into the combustion furnace. The jacket heats the carbonization furnace; part of the flue gas from the jacket returns to the carbonization furnace, and the oxygen in the flue gas reacts with the biomass to generate heat inside the carbonization furnace. The invention adopts an internal and external combined heating method, can flexibly control the carbonization temperature and reaction rate, and the generated biochar is high in quality and stable.

Description

A system and method for producing carbon from biomass

technical field

The invention relates to a method for making charcoal, in particular to a method for making charcoal from biomass.

Background technique

The charcoal made of biomass has the characteristics of smokeless, odorless, and high calorific value. It can be directly applied to the soil or used as a raw material for charcoal-based fertilizers. On the one hand, it improves the soil and increases its fertility. The storage time of carbon in the soil reduces the negative impact of the greenhouse effect on global climate change. In addition, biochar is a good adsorbent with a large specific surface area, and its surface is rich in oxygen-containing active functional groups, which can purify water quality and adsorb some common environmental pollutants in soil such as heavy metals and pesticides. Because of its low cost, it has been widely used in chemical industry, metallurgy, environmental protection, agriculture and other fields. At the same time, the carbonization of biomass into high value-added charcoal is one of the effective methods to improve the rural environment and solve the outlet for biomass.

Biomass carbonization furnaces are divided into internal heat type and external heat type according to the heating method: ①The internal heat type is to pass in a part of the air, use the biomass itself to generate heat, and use three combinations of heat conduction, heat convection, and heat radiation to provide carbonization equipment itself. required heat. The advantages are that no additional energy is required, the cost is low, the operation is simple, the carbonization time is short, and the carbon production capacity per unit volume is strong. The disadvantage is that the consumption of biomass raw materials is large and the temperature is not easy to control, and the quality of the charcoal is not as good as that produced by the external heating method; ②The external heating method uses heat conduction to transfer heat from an external heat source to the carbonization furnace. The advantage is that the charcoal is of high quality, and the carbonization temperature and heating rate can be flexibly controlled. The disadvantage is that it needs to consume additional energy, and the investment and operation costs are high. The temperature of the furnace is always lower than the temperature of the furnace wall, and it cannot ensure that raw materials of different shapes and particle sizes are heated evenly.

Biomass carbonization furnaces are divided into batch type and continuous type according to the feeding and discharging methods: ① The batch type includes tube type and kiln type, which cannot realize continuous feeding and has limited production capacity. And the carbonization time is long, the temperature is not easy to control, and the quality of biochar is difficult to control; ②The continuous biomass carbonization equipment can operate continuously, which is conducive to industrialization and is the development trend of biomass carbonization equipment.

In addition, a large amount of tar and pyrolysis gas will be produced in the process of biomass carbonization. If these by-products are not fully utilized, they will not only cause environmental pollution, but also cause waste of resources and reduce energy utilization.

At present, the existing biochar production systems will have at least one of the following problems: ①The production capacity is small, and it is difficult to meet the needs of large-scale production, such as kiln-type furnaces, kettle-type furnaces, and screw propeller furnaces; ②It is difficult to control the temperature in the furnace, and the biochar Difficult to guarantee quality, such as vertical flow furnace; ③ high requirements on raw materials, limited application range, such as rotary kiln; ④ high energy consumption, high production cost, and environmental pollution. For the above problems,

Contents of the invention

Purpose of the invention: The present invention provides a biomass charcoal system and method. The system adopts an internal and external heating method during the biomass charcoal production process so that the carbonization temperature and reaction rate can be flexibly adjusted; the present invention converts by-products produced during the carbonization process The tar and pyrolysis gas are burned, and the high-temperature flue gas produced by the combustion adopts a combined internal and external heating method to provide heat for the biomass carbonization process, realizing continuous feeding and discharging and energy cascade utilization.

Summary of the invention: The biomass carbon production system provided by the present invention includes a biomass feeder, a silo, a carbonization furnace, a jacket, a separator, a combustion furnace, an air preheater, a dust collector, an induced draft fan, a chimney, a blower, and a discharge Warehouse, circulation fan, start combustion chamber. The silo is connected with the biomass feeder, and the biomass feeder is connected with the feed port of the carbonization furnace; there is a jacket outside the carbonization furnace; the pyrolysis gas outlet on the top of the carbonization furnace is connected with the pyrolysis gas inlet of the separator; the lower part of the separator It is the carbon powder outlet, the carbon powder outlet is connected to the discharge bin, the pyrolysis gas outlet on the upper part of the separator is connected to the pyrolysis gas inlet of the burner; the high-temperature flue gas outlet of the burner is connected to the high-temperature flue gas inlet of the jacket, The blower communicates with the combustion gas inlet of the burner through the air preheater; the flue gas outlet of the jacket communicates with the air preheater and the circulation fan respectively; Connect with the chimney; start the combustion chamber and connect the carbonization furnace.

Due to the high heat and mass transfer rate of the fluidized bed reactor, the temperature in the bed is uniform and easy to control, the operation without moving parts is reliable and the cost is low, the operating flexibility range is wide, and the production capacity of a single device is large, which meets the needs of modern large-scale production. There are two types of fluidized bed reactors: bubbling fluidized bed and circulating fluidized bed. Considering that the circulating fluidized bed wears heavily on the bed material, the cost of subsequent industrial promotion is high, and the density of biomass is low, the content of volatile matter is high, and it is easier to make charcoal compared with coal. The carbonization furnace of the present invention adopts a bubbling fluidized bed

The biomass feeder of the present invention adopts a spiral frequency conversion type biomass feeder, which is beneficial to continuous feeding and controls the feeding speed.

The working principle of the biomass carbon production system provided by the present invention: first ignite the starting combustion chamber of the carbonization furnace, when the temperature in the carbonization furnace rises to a certain temperature range, the starting combustion chamber will be extinguished, and the corresponding fuel valve and air supply valve will be closed , at this time, put the biomass raw material into the silo, the biomass raw material in the silo enters the biomass feeder, and the biomass feeder continuously sends the biomass raw material into the carbonization furnace; the biomass raw material is in the carbonization furnace The pyrolysis gas entrained with carbon powder generated by the reaction under heat is discharged from the pyrolysis gas outlet on the top of the carbonization furnace into the separator, and the gas-solid separation is realized in the separator. The carbon powder is discharged from the lower part of the separator, and the pyrolysis gas The pyrolysis gas is discharged from the outlet of the top of the separator to the burner; the pyrolysis gas and the charcoal powder that has not been separated by the cyclone separator are fully burned in the combustion furnace, and the high-temperature flue gas generated by the combustion first enters the jacket of the carbonization furnace, which is beneficial to the carbonization. The furnace is heated externally to provide part of the heat for the pyrolysis of biomass in the carbonization furnace. The flue gas from the jacket is divided into two paths: ① one path returns to the carbonization furnace through the circulating fan, the oxygen in the flue gas reacts with the biomass, and heat is released inside the carbonization furnace to provide part of the heat for the carbonization of the biomass; ② one path enters the air The preheater heats the combustion air required by the combustion furnace. The flue gas from the air preheater passes through the dust collector and the induced draft fan in turn, and then is emptied through the chimney.

Beneficial effect:

(1) The present invention adopts an internal and external combined heating method, and controls the heat transferred inside the carbonization furnace jacket by adjusting the flue gas temperature and flow rate out of the combustion furnace; Circulating the amount of flue gas, controlling the heat release of the carbonization furnace itself. This combined internal and external heating method can flexibly adjust the carbonization temperature and reaction rate, which can not only ensure a higher reaction rate, but also ensure the quality of biochar and obtain a higher carbon production rate.

(2) The present invention adopts a bubbling fluidized bed as a carbonization furnace, and the entire cross-section reacts uniformly without local overheating or overcooling. Biomass has strong applicability and can adapt to granular fuels such as peanut shells, rice husks, corn cobs, wood pellets, and crop straw briquettes. A single unit has a large processing capacity, which is conducive to large-scale industrial application.

(3) The combustible components and tar produced by the carbonization furnace are passed into the combustion furnace. On the one hand, energy cascade utilization is realized, without energy waste, without relying on or minimizing dependence on external energy sources, and realizing the transformation of biomass into powdered carbon , low operating cost; on the other hand, effectively solve the problem of environmental pollution.

(4) Continuous feeding and discharging is conducive to large-scale industrial application.

(5) The system flow is simple, convenient and controllable, and each unit equipment is a mature product with safe and stable operation, and obvious economic and environmental benefits.

Description of drawings

Fig. 1 is a schematic structural diagram of the biomass charcoal production system of the present invention.

In terms of materials, a-cooling water; b-high-temperature flue gas; c-pyrolysis gas; d-biochar; e-bottom residue; f-start-up fuel (diesel, natural gas or liquefied petroleum gas); h-fly ash.

detailed description

As shown in Fig. 1, the silo 2 of the biomass charcoal system of the present invention is connected with the biomass feeder 1, and the biomass feeder is a screw feeder adjusted by frequency conversion, which can continuously feed the carbonization furnace 3 into raw material. Material raw materials, and the feeding speed can be adjusted; the biomass feeder 1 is connected to the feed port of the carbonization furnace 3; the carbonization furnace 3 is provided with a jacket 4, and the high-temperature flue gas in the jacket 4 releases heat , heating the carbonization furnace 3; the pyrolysis gas outlet at the top of the carbonization furnace 3 is connected with the pyrolysis gas inlet of the separator 5; The pyrolysis gas outlet is connected to the pyrolysis gas inlet of the burner 6; the high-temperature flue gas outlet of the burner 6 is connected to the high-temperature flue gas inlet of the jacket 4, and the blower 11 is connected to the gas-supporting gas inlet of the burner 6 through the air preheater 7; The flue gas outlet of the jacket 4 communicates with the air preheater 7 and the circulating fan 13 respectively; the circulating fan 13 is connected with the inside of the carbonization furnace 13, and the air preheater 7 is finally connected with the chimney 10 through the dust collector 8 and the induced draft fan 9 in turn; start The combustion chamber 14 contains starting fuel, which can heat the carbonization furnace and preheat the carbonization furnace.

In order to enhance the heat exchange effect and prolong the residence time of the high-temperature flue gas in the jacket, the jacket material is made of heat-resistant steel 0Cr25Ni20, and the jacket is equipped with fins and deflectors.

The process of carbon production using the biomass carbon production system in Figure 1 is as follows:

There are many types of biomass, and wheat straw is taken as an example.

(A) ignite the start-up fuel in the start-up combustion chamber 14, preheat the carbonization furnace, and when the central temperature of the carbonization furnace is stable at 300-650°C, put the biomass raw material wheat straw into the feed bin 2, and the wheat straw 6.6% moisture, 7.9% ash, 70.7% volatile matter, 14.8% fixed carbon; start the biomass feeder 1 to send the biomass raw material into the carbonization furnace 3, and then start the combustion chamber 14 to extinguish and close the corresponding fuel valve and air supply valves;

(B) Biomass raw materials are heated and reacted in the carbonization furnace 3. The carbonization furnace 3 is a bubbling fluidized bed. The temperature of the dense phase zone and the dilute phase zone of the carbonization furnace 3 is controlled at about 420°C, and the slight negative pressure in the furnace is about -100Pa Left and right, the state wind speed is about 3m/s; the pyrolysis gas entrained with carbon powder produced by the reaction of biomass raw materials is discharged from the top of the carbonization furnace 3 into the separator 5, and the gas-solid separation is realized in the separator, and the carbon powder is discharged from the separator 5 The charcoal powder discharge outlet of the lower part is discharged into the discharge bin 12, and the temperature of the charcoal discharged from the lower part of the discharge bin 12 needs to be lower than 80° C. to prevent the charcoal from burning after contacting with air. Pyrolysis gas and charcoal powder not decomposed by the separator 5 enter the combustion furnace 6;

(C) Start the blower 11, the combustion-supporting air enters the interior of the combustion furnace 6 through the air preheater 7, and the pyrolysis gas and the charcoal powder that has not been decomposed by the separator 5 enter the combustion furnace 6 and burn fully; the temperature in the combustion furnace is controlled at 800 ° C About, lower than the sintering temperature of wheat, the oxygen content of the high-temperature flue gas produced by combustion is controlled at about 2%; After the flue gas outlet of set 4 is discharged, it is divided into two paths, and one path is returned to the carbonization furnace 3 through the circulating fan 13. The oxygen in the flue gas reacts with the biomass raw material, and heat is released inside the carbonization furnace 3 to provide a part of the carbonization of biomass. The heat; the other way enters the air preheater 7 to heat the combustion air required by the combustion furnace 6;

(D) The flue gas discharged from the air preheater 7 is discharged into the air through the dust collector 8, the induced draft fan 9, and the chimney 10 in sequence.

Claims (7)

1. a kind of biomass charcoal making system, including biomass feeding machine (1), feed bin (2), retort (3), chuck (4), separator (5), combustion furnace (6), air preheater (7), chimney (10), air blower (11), discharging bin (12), circulating fan (13) and startup burning Room (14)；It is characterized in that：

Feed bin (2) is connected with biomass feeding machine (1), and biomass feeding machine (1) is connected with retort (3) charging aperture；Retort (3) it is outside to be provided with chuck (4)；Pyrolysis gas outlet and separator (5) pyrolysis gas inlet communication at the top of retort；Under separator (5) Portion is powdered carbon outlet, and powdered carbon outlet is connected with discharging bin (12), the pyrolysis gas outlet and burner on separator (5) top (6) pyrolysis gas inlet communication；The high-temperature flue gas outlet of burner (6) is connected with chuck (4), and air blower (11) passes through air preheater (7) connected with burner (6)；

The exhanst gas outlet of chuck (4) is connected with air preheater (7) and circulating fan (13) respectively；In circulating fan (13) and retort Portion is connected, and air preheater (7) is connected with chimney (10)；

Start combustion chamber (14) connection retort (3).

2. a kind of biomass charcoal making system according to claim 1, it is characterised in that：The air preheater (7) passes sequentially through Deduster (8) and air-introduced machine (9) are finally connected with chimney (10).

3. a kind of biomass charcoal making system according to claim 1, it is characterised in that：Chuck (4) material uses heat resisting steel Fin and deflector are provided with 0Cr25Ni20, chuck (4).

4. a kind of biomass charcoal making method, comprises the following steps：

(A) the startup ignited fuel in combustion chamber (14) will be started, when retort central temperature is risen in certain limit, Biomass material is put into feed bin (2), starts biomass feeding machine (1) and sends into biomass material in retort (3), now Combustion chamber (14) will be started to extinguish and close corresponding fuel valve and air-supply valve；

(B) biomass material is heated in retort (3) and reacted, the entrainment powdered carbon for the generation that reacted by biomass material Pyrolysis gas be discharged into separator (5) at the top of the retort (3) and realize gas solid separation, charcoal of the powdered carbon from separator (5) bottom Powder outlet is discharged, into discharging bin (12), and the powdered carbon that pyrolysis gas and the device (5) that is not separated are decomposed enters combustion furnace (6)；

(C) start air blower (11), it is internal that combustion air enters combustion furnace (6) by air preheater (7), pyrolysis gas and be not separated The powdered carbon that device (5) is decomposed enters combustion furnace (6) fully burning afterwards；The high-temperature flue gas that combustion furnace (6) comes out enters retort Chuck (4) carries out external heat to retort, and flue gas is divided into two-way after the exhanst gas outlet discharge of chuck (4), all the way by following The oxygen that ring blower fan (13) is back in retort (3), flue gas reacts with biomass material, is put inside retort (3) Going out heat, there is provided a part of biomass carbonated required heat；Another road enters air preheater (7), to combustion-supporting needed for combustion furnace Air is heated；

(D) flue gas discharged from air preheater (7) is sequentially passed through during deduster (8), air-introduced machine (9), chimney (10) be drained into air.

5. a kind of biomass charcoal making method according to claim 4, it is characterised in that：Retort (3) central temperature is controlled At 300~650 DEG C, tiny structure -100Pa or so in stove, state wind speed about 3m/s.

6. a kind of biomass charcoal making method according to claim 4, it is characterised in that：Discharging bin (12) bottom is ejected The temperature of charcoal is less than 80 DEG C.

7. a kind of biomass charcoal making method according to claim 4, it is characterised in that：Furnace temperature control 650~ 850 DEG C, but no more than biomass sintering temperature.