Method of continuous pyrolysis and carbonization of agricultural and forestry biomass

Patent metadata

Field	Value
Publication number	US-10253263-B2
Application number	US-201515322128-A
Country	US
Kind code	B2
Filing date	Apr 2, 2015
Priority date	Jun 24, 2014
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

The invention belongs to the field of biomass energy utilization, and a continuous pyrolysis and carbonization method of agricultural and forestry biomass is disclosed. The method comprises the following steps: feeding biomass feedstock to a dryer for drying, then transporting to a continuous pyrolysis apparatus for pyrolyzing to obtain pyrolysis semicoke and pyrolysis volatiles; and transporting the pyrolysis semicoke to a carbonization apparatus for carbonization to obtain biomass charcoal and semi-coke carbonized volatiles; then discharging the pyrolysis volatiles and the semi-coke carbonized volatiles, and cooling to obtain tar, wood vinegar and pyrolysis gas; introducing the pyrolysis gas into a combustion apparatus for combustion to obtain a high temperature flue gas; and finally transporting the high temperature flue gas into pyrolysis apparatus and carbonization apparatus for supplying heat, then the flue gas after supplying heat is delivered to the dryer and discharging tail gas. In the method, continuous and stable pyrolysis and carbonization of biomasses is realized, the pyrolysis step and the carbonization step are finished in the same system with separate step, transport efficiency is significantly increased, reaction conditions are steady and controllable, and the energy utilization efficiency is high.

First claim

The invention claimed is:

1. A method of continuous pyrolysis and carbonization of agricultural and forestry biomass, characterized in: using a continuous pyrolysis process to initially pyrolyze biomass, then using a fixed bed carbonization process to fully carbonize pyrolytic semicoke of a primary pyrolysis product, comprising the following steps in detail:
(1) transporting biomass feedstock into a drying oven for drying by a feeding apparatus;
(2) transporting the dried biomass feedstock to a continuous pyrolysis apparatus for pyrolysis by a feeding apparatus, wherein the resulting products are pyrolysis semicoke and pyrolysis volatiles;
(3) transporting the pyrolysis semicoke to a carbonization apparatus for carbonization to obtain biomass charcoal and semicoke carbonization volatiles; collecting the biomass charcoal;
(4) discharging the pyrolysis volatiles and the semicoke carbonization volatiles, cooling them to obtain tar, wood vinegar and pyrolysis gas, and collecting tar and wood vinegar;
(5) feeding the pyrolysis gas into a combustion furnace for combustion to obtain a high temperature flue gas;
(6) transporting the high temperature flue gas through a distribution valve into the pyrolysis apparatus and carbonization apparatus respectively for supplying heat to the pyrolysis apparatus and carbonization apparatus, then the flue gas after supplying heat is transported to the drying oven, thereby drying the biomass feedstock, and finally tail gas is discharged;
wherein the pyrolysis of step (2) and the carbonization of step (3) are performed continuously and subsequently, and after the dried biomass feedstock comes into the pyrolysis apparatus, it is transported to the carbonization apparatus for carbonization by a spiral transporting rod while being pyrolyzed.

2. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 1 , characterized in that:
the drying temperature of step (1) is less than 200° C., and the drying time is 10-30 min;
the pyrolysis temperature of step (2) is 400-600° C., and the pyrolysis time is 3-8 min;
the carbonization temperature of step (3) is 500-800° C., and the carbonization time ≥30 min.

3. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 1 , characterized in that: the drying medium of the drying oven of step (1) is the flue gas after supplying heat to the pyrolysis apparatus and the carbonization apparatus, the flue gas comes into the drying oven for drying the feedstock after supplying heat to the pyrolysis apparatus and carbonization apparatus; and the flue gas is the product from the combustion of pyrolysis gas obtained after the pyrolysis and carbonization of the biomass feedstock.

4. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 1 , characterized in that: the biomass charcoal of step (3) is transported to a charcoal storage box from the carbonization apparatus, cooled naturally and discharged;
and the pyrolysis volatiles and the semicoke carbonized volatiles of step (4) are discharged together from the carbonization apparatus into a condenser for condensation.

5. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 1 , characterized in that: the apparatus used in the method of continuous pyrolysis and carbonization of agricultural and forestry biomass is a continuous pyrolysis and carbonization apparatus of agricultural and forestry biomass;
the apparatus comprises a feeding apparatus, a pyrolysis apparatus, a carbonization apparatus, and a heating apparatus for heating the pyrolysis apparatus and carbonization apparatus; the pyrolysis apparatus comprises a pyrolysis furnace, a pyrolysis tube throughout the pyrolysis furnace and a spiral conveyor installed inside the pyrolysis tube; an outlet end of the pyrolysis tube is connected to the carbonization apparatus; and the carbonization apparatus comprises a shell and a heat exchange tube installed inside the shell.

6. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 5 , characterized in that: the heating apparatus comprises the combustion furnace, an oil-gas combustor and the distribution valve; the combustion furnace is built inside the pyrolysis furnace, and the oil-gas combustor is installed outside the combustion furnace;
the distribution valve has a heat inlet, two heat outlets and a gas distributing valve; the heat inlet of the distribution valve is connected to a flue gas outlet of the combustion furnace, the two heat outlets of the distribution valve are connected to the pyrolysis furnace in the pyrolysis apparatus and the heat exchange tube in the carbonization apparatus respectively.

7. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 5 , characterized in that: the continuous pyrolysis and carbonization apparatus of agricultural and forestry biomass further comprises the drying oven, a pyrolysis feeding hopper and a spiral conveyor; a material input end of the drying oven is connected to an output end of the feeding apparatus, and a material output end of the drying oven is connected to an input end of the spiral conveyor; an output end of the spiral conveyor is connected to an input end of the pyrolysis feeding hopper, and an output end of the pyrolysis feeding hopper is connected to an input end of the pyrolysis tube.

8. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 7 , characterized in that: a drying medium inlet of the drying oven is connected to a gas outlet of the pyrolysis furnace and an outlet of the heat exchange tube by pipelines respectively.

9. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 5 , characterized in: further comprising a condenser and a liquid collecting box; wherein a material inlet of the condenser is connected to the carbonization apparatus, a liquid outlet of the condenser is connected to an inlet of the liquid collecting box, and a gas outlet of the condenser is connected to a fuel supply inlet of the oil-gas combustor.

10. The method of continuous pyrolysis and carbonization of agricultural and forestry biomass according to claim 5 , characterized in: further comprising a gas storage tank and a three-way valve; wherein a gas inlet of the gas storage tank, the gas outlet of the condenser and the fuel supply inlet of the oil-gas combustor are connected by the three-way valve, and gas outlet of the gas storage tank is connected to the fuel supply inlet of the oil-gas combustor.

Assignees

• Univ South China Agricult

Inventors

• Jiang Enchen
• Wang Mingfeng
• Guo Xinhui
• Xu Xiwei
• Shi Dongdong
• Li Shibo
• Zhang Shijun

Classifications

• Y02E50/14

  Cross-Sectional Technologies · mapped topic

• C10B47/44

  with conveyor-screws · CPC title

• Y02P20/145

  the feedstock being materials of biological origin · CPC title

• C10B49/02 Primary

  with hot gases or vapours, e.g. hot gases obtained by partial combustion of the charge · CPC title

• C10B57/02

  Multi-step carbonising or coking processes · CPC title