Device and method for efficiently preparing biogas by two-stage high-temperature anaerobic fermentation of composite materials

Abstract

The invention discloses a device for effectively preparing biogas through secondary high-temperature anaerobic fermentation of a composite material and a method thereof. The device comprises a first primary anaerobic fermentation tank and a second primary anaerobic fermentation tank, wherein the first primary anaerobic fermentation tank is connected with one end of a first heat exchanger; the other end of the first heat exchanger is respectively connected with the first primary anaerobic fermentation tank and a secondary anaerobic fermentation tank; the second primary anaerobic fermentation tank is connected with one end of the second heat exchanger, and the other end of the second heat exchanger is respectively connected with a second primary anaerobic fermentation tank and the secondary anaerobic fermentation tank; a biogas transporting port is formed in the secondary anaerobic fermentation tank. The method comprises the following steps: (1) classifying the materials; (2) pre-processing the classified materials; (3) preparing a primary processing material and a secondary processing material; (4) feeding into the secondary anaerobic fermentation tank and refluxing; and (5) collecting the biogas generated by the secondary anaerobic fermentation tank. The device has the advantages of stable long-time running, strong endurance capacity on the ammonia nitrogen, the acid base and the volatile organic acid and high gas productivity.

Description

technical field [0001] The invention relates to the field of biogas preparation, in particular to a device and method for efficiently preparing biogas by secondary high-temperature anaerobic fermentation of composite materials. Background technique [0002] Urban and rural waste is an important source of pollution, polluting water, soil and the atmosphere. 60% of river pollution in our country comes from livestock and poultry manure, and environmental governance is very urgent. Since the adoption of conventional environmental protection treatment means is a negative investment, it brings a huge burden to the government. With the way of recycling waste, the current technology, whether it is the production of solid fertilizer or the utilization of biogas, cannot realize real industrialization due to the low return on investment. [0003] China has a long history of using anaerobic fermentation to produce biogas. As of the end of 2010 (statistics from the Ministry of Agricul...

AI Technical Summary

Problems solved by technology

[0015] 1. The materials are not classified together for pretreatment unit, and the pretreatment is more difficult due to the different properties of the materials

[0016] 2. The mixed materials enter the primary fermentation tank together, and the residence time is 15-20 days. The primary fermentation tank is the main fermentation tank of the system. Anaerobic fermentation is divided into acid production stage and methane production stage. Due to the different components of various materials, The time difference in the hydrolysis and acidification stage is very large. For example, the hydrolysis and acidification time of pig manure only needs 3 days, while the hydrolysis and acidification stage of kitchen waste requires 5 days. The hydrolysis and acidification stage of livestock carcasses takes longer, so the hydrolysis and acidification of mixed materials will take The probability of material rancidity increases. Even for a single material, the pH of the acid production stage decreases, and the best environment for the methanation stage is under weak alkaline conditions, so the growth of methanogenic bacteria will be inhibited, and the gas production efficiency will be greatly affected. At the same time, the acidic environment and time required for the hydrolysis and acidification stage will not be fully completed due to the interference of the methanation stage, and the insufficiency of the hydrolysis and acidification stage will also reduce the efficiency of methane production

[0017] 3. The residence time of the secondary anaerobic fermentation tank is 3-5 days. This part is mainly responsible for the collection of fermentation residual gas and the role of biogas storage cabinet, and has no effect on the overall fermentation process.

[0018] 4. The fermenter adopts a ring-shaped circulating water pipe to ensure the temperature of the fermenter. The hot water pipeline of the fermenter will scale and cause the heat conduction capacity to weaken. Long-term operation needs to increase the heat supply of the system. If it is repaired, clean the scale The system must be shut down to complete the emptying of the tank, and the maintenance cost is high

[0019] 5. This form of secondary fermentation system has low gas production load, poor resistance to ammonia nitrogen, pH and volatile fatty acids, and the system is very easy to acidify and run unstable, especially for materials with high fat and protein content. The processing capacity is quite poor

Images