Process for producing biogas by utilizing methane-straw gas coproduction device

Abstract

The invention discloses a process for producing biogas by utilizing a methane-straw gas coproduction device. The device comprises a gathering tank, a solid-liquid separator, a heat exchanger, a UASB (Upflow Anaerobic Sludge Blanket) reactor, a granular sludge storage tank, an aeration tank, a settling pond, a straw gasification furnace, a biogas storage bin, a dehydrating tower and a desulfurizing tower, wherein the UASB reactor comprises an organic wastewater inlet, a three-phase separator, a liquid outlet and a methane outlet; the straw gasification furnace comprises an emptying tube, a fuel inlet, a furnace body, a fire grate, a tapered ash chamber, a water seal tank and a fuel outlet; and the biogas storage bin is a deformable elastic storage bin and comprises a methane inlet, a fuel inlet and a mixed gas outlet. The invention also discloses process steps of producing the biogas. The production pattern of methane-straw gas coproduction provided by the invention effectively solves the contradiction between the fermentation cost and the fermentation efficiency in case of independent operation of the traditional methane project, successfully realizes continuous dynamic fermentation of medium and high temperatures at low cost and greatly improves the productivity of the methane project.

Description

technical field [0001] The invention relates to a device and a production process for producing biogas and straw gas, in particular to a process for producing biogas by using a biogas and straw gas dual-gas cogeneration device. Background technique [0002] Biomass is all the organic matter on the earth that directly or indirectly originates from the photosynthesis of green plants and converts solar energy into chemical energy. In a broad sense, it refers to all organic matter (such as: animals, plants, microorganisms, etc.), and in a narrow sense, it is useless to humans. And harmful urban and rural organic waste (such as: crop straw, dead wood, human and animal manure, catering kitchen waste, etc.) and biomass energy crops artificially planted using marginalized wasteland. [0003] Biomass energy is the form of energy indirectly expressed by solar energy through biomass, and it is a renewable green energy with huge reserves; it is aimed at moist organic waste with high moi...

AI Technical Summary

Problems solved by technology

[0006] (1) The biggest key point of biogas engineering is how to obtain the best fermentation state and the highest fermentation efficiency with the lowest operating cost: as we all know, a good medium-high temperature fermentation state (rather than a very high temperature fermentation state) and a continuous flow fermentation state (rather than Non-stationary fermentation state or intermittent flow fermentation state) will greatly improve the efficiency of anaerobic fermentation; although the former can be achieved by artificially adding warming heat sources (such as: biogas boiler hot water, solar hot water, waste heat from generators, etc.) , the latter can be achieved by artificially adding stirring power (such as electric machinery, etc.); however, this addition requires energy consumption, and if more energy is added, the energy consumption will be large and the operating cost will be high, otherwise it will inevitably affect the fermentation efficiency (especially in the cold northern regions Worse); in a dilemma, under the last resort, domestic biogas projects generally adopt a compromise method of expanding original equipment investment (in order to increase fermentation volume) on the one hand, and reducing daily operating costs (in order to reduce heating and stirring) on ​​the other hand. Over time, it will inevitably be embarrassing

[0007] (2) The biggest profit point of biogas projects lies in biogas rather than biogas: the former is watermelon, and the latter is sesame; at present, domestic biogas projects that have invested heavily in construction generally focus on biogas rather than biogas, and even discard biogas; however, if If biogas is calculated separately, the cost is generally high and the benefit is low, or even negative benefit. Over time, it will be embarrassing

[0010] (1) The key point of the straw gasification project is how to obtain the highest gas quality at the lowest operating cost: as we all know, straw gas contains a large amount of tar, ash and other harmful impurities (≥500mg / m 3 ), if no effective purification treatment is carried out, the terminal system will be blocked and scrapped soon; at present, domestic straw gasification projects generally adopt the traditional fan-powered suction (hookah type) multi-stage cycle condensate washing process technology and equipment to remove it Coke dust removal and purification treatment, although the gas tar content can reach ≤50mg / m 3 The standard of the Ministry of Agriculture (even can reach ≤10mg / m 3 lower standard), but still failed to reach the quality standard of the pipeline network gas level (the gas tar content is approaching zero). Over time, the accumulation of traces of tar will still cause the system to eventually cause "vascular embolism" and "myocardial infarction" (the hazards are especially Especially with gas meter)

[0011] (2) The biggest profit point of the straw gasification project lies in whether the abundant gas heat energy generated during the gasification process can be effectively utilized: the initial temperature of the straw gas is about 400°C, and the flow rate is about 10m / s. The project generally adopts the traditional fan power suction (hookah type) multi-stage cycle condensate washing process technology and equipment to decoke and dedust and purify it. As a result, a large amount of precious gas heat energy and aerodynamic energy are unnecessarily buried in cooling, decoking, and dust removal. In the tower, and a large amount of dirty, unusable and extremely difficult to degrade high-temperature sewage is finally discharged, causing serious secondary environmental pollution problems

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