Energy storage method and device for biomass cascade pyrolysis coupled with new energy power generation

An energy storage method of an energy storage device for biomass cascade pyrolysis coupled with new energy power generation, wherein the energy storage device for the biomass cascade pyrolysis comprises a feeding system, a cascade pyrolysis system, a post-treatment system and an output system, wherein

• the feeding system comprises a biomass feedstock bin, a feedstock-conveying device, a first gas locker and a second gas locker sequentially connected;
• the cascade pyrolysis system comprises a low-temperature pyrolysis device and a high-temperature pyrolysis device, and the low-temperature pyrolysis device is connected with a heat transfer oil storage box;
• the post-treatment system comprises a condensation system, a power generation system and an exhaust treatment device, the power generation system comprises a booster fan, an internal combustion engine and a power generator;
• the output system comprises a high-temperature storage bin and a low-temperature storage bin, the high-temperature storage bin is configured to store bio-char delivered by the high-temperature pyrolysis device and discharge the pre-cooled bio-char into the low-temperature storage bin, wherein an electric energy required by various systems of the energy storage device for the biomass cascade pyrolysis is supplied by a new energy power generation system;
• when the new energy power generation system aims to realize stable electric energy output, the energy storage device for the biomass cascade pyrolysis further comprises a mixing device;
• the condensation system comprises a first gas-liquid heat exchanger, a spray tower heat exchanger and a gas storage tank sequentially connected;
• a high-temperature pyrolytic gas outlet of the high-temperature pyrolysis device is connected with an inlet of the first gas-liquid heat exchanger, an outlet of the first gas-liquid heat exchanger and a low-temperature pyrolytic gas outlet of the low-temperature pyrolysis device are both connected with an inlet of the spray tower heat exchanger, and the mixing device mixes a bio-oil captured by the condensation system with the bio-char from the low-temperature storage bin to prepare a slurry fuel;
• when the new energy power generation system aims to consume redundant electric energy, the energy storage device for the biomass cascade pyrolysis further comprises a hydrogen making device, the condensation system comprises a first gas-liquid heat exchanger, a second gas-liquid heat exchanger, a spray tower heat exchanger and a gas storage tank sequentially connected;
• the high-temperature pyrolytic gas outlet of the high-temperature pyrolysis device is connected with the inlet of the first gas-liquid heat exchanger;
• the low-temperature pyrolytic gas outlet of the low-temperature pyrolysis device is connected with an inlet of the second gas-liquid heat exchanger;
• an outlet of the second gas-liquid heat exchanger is connected with the inlet of the spray tower heat exchanger;
• the high-temperature pyrolytic gas of the high-temperature pyrolysis device sequentially runs through the first gas-liquid heat exchanger, the second gas-liquid heat exchanger, and the spray tower heat exchanger to produce low-temperature, medium-temperature and high-temperature bio-oils by three-stages condensation mode;
• the low-temperature pyrolytic gas of the low-temperature pyrolysis device is connected to the condensation system through the second gas-liquid heat exchanger to produce the medium-temperature and high-temperature bio-oils sequentially by condensation, the medium-temperature and low-temperature bio-oils produce corresponding products by hydrogen added by the hydrogen making device, and the high-temperature bio-oil is configured to subsequently prepare an electrochemical high-quality activated carbon;
• a bottom liquid outlet of the spray tower heat exchanger is configured to output a condensed bio-oil, and a top gas outlet is connected with the gas storage tank;
• an outlet of the gas storage tank is connected with an inlet of the booster fan;
• an outlet of the booster fan is connected with the internal combustion engine;
• the internal combustion engine is connected with the power generator;
• the power generator supplies power to the high-temperature pyrolysis device;
• an exhaust of the internal combustion engine sequentially flows through the low-temperature pyrolysis device and the biomass feedstock bin for recovery of heat energy in the exhaust and finally is discharged after being treated by the exhaust treatment device;
• wherein a heat exchange amount of the first gas-liquid heat exchanger in the condensation system is configured to heat the heat transfer oil for use by the low-temperature pyrolysis device, and heat exchange amounts of the second gas-liquid heat exchanger and the spray tower heat exchanger are configured to dry and preheat a raw biomass in the biomass feedstock bin;
• the energy storage method comprises the following steps:
• 1) device startup stage:
• subjecting the electric energy supplied by the new energy power generation system to preheat the low-temperature pyrolysis device and the high-temperature pyrolysis device, wherein by electric heating, the heat transfer oil storage box is heated to 250 to 500° C.;
• wherein the low-temperature pyrolysis device is connected with the heat transfer oil storage box and a circulating heat transfer oil is introduced to the heat transfer oil storage box to provide heat required for low-temperature pyrolysis;
• 2) conveying the raw biomass in the biomass feedstock bin by the feedstock-conveying device to the low-temperature pyrolysis device for pre-pyrolysis, wherein the circulating heat transfer oil of the heat transfer oil storage box provides a heat source required for the pre-pyrolysis;
• wherein the heat source of the heat transfer oil storage box comes from the electric energy of the new energy power generation system, the exhaust heat energy of the power generation system, and the high-temperature heat energy recovered from the condensation system and the high-temperature storage bin, comprising the followings:
• 2.1) heating the heat transfer oil storage box by electric heating of the new energy power generation system;
• 2.2) subjecting the exhaust discharged by the power generator of the power generation system to run through the heat transfer oil storage box, and recovering and transferring the heat energy in the high-temperature exhaust to the heat transfer oil in the heat transfer oil storage box;
• 2.3) connecting a liquid side of the first gas-liquid heat exchanger in the condensation system with the heat transfer oil storage box, connecting a gas side inlet with the high-temperature pyrolytic gas, and recovering heat in the high-temperature pyrolytic gas for the heat transfer oil storage box in the low-temperature pyrolysis device;
• 2.4) configuring the high-temperature storage bin to store a bio-char delivered by the high-temperature pyrolysis device, and with circulating nitrogen as a heat exchange medium inside, recovering and transferring the high-temperature heat energy in the high-temperature bio-char to the heat transfer oil in the heat transfer oil storage box;
• 3) subjecting a pre-pyrolysed char in the low-temperature pyrolysis device subsequently to enter the high-temperature pyrolysis device for deep pyrolysis, wherein a temperature of the deep pyrolysis is 500 to 700° C.;
• the electric energy required by the high-temperature pyrolysis device is supplied by the new energy power generation system;
• 4) storing the high-temperature pyrolytic gas and the low-temperature pyrolytic gas in the gas storage tank after the bio-oil is separated out by condensation;
• after the energy storage device for the biomass cascade pyrolysis runs stably, connecting the gas storage tank to a burner for combustion based on requirements to supplement the heat energy and electric energy required by the low-temperature pyrolysis device and the high-temperature pyrolysis device;
• meanwhile, recovering the heat energy from products to, based on different temperatures, supplement the heat required by the low-temperature pyrolysis device and the biomass feedstock bin;
• wherein a heat exchange amount of the first gas-liquid heat exchanger in the condensation system is configured to heat the heat transfer oil for use by the low-temperature pyrolysis device, and heat exchange amounts of the second gas-liquid heat exchanger and the spray tower heat exchanger are configured to dry and preheat a raw biomass in the biomass feedstock bin.