Recycling system and technique for producing wastewater by cellulosic ethanol

Abstract

The invention discloses a recycling system for producing a wastewater by cellulosic ethanol, and simultaneously provides a technique for recycling comprehensive utilization on a cellulosic ethanol wastewater by using the system. Biogas fermentation adopts a serial fermentation mode of high-temperature biogas fermentation and medium-temperature biogas fermentation, so that the fermentation efficiency is higher, the biogas capacity is higher, the chemical oxygen demand (CODCr) removal rate can effectively achieve 95-98%, and fermentation is more thorough, so that the reuse rate of fermented effluent is effectively improved, consumption of fresh water resources is reduced, and the subsequent wastewater throughput and treatment cost are reduced. First-stage high temperature fermentation adopts quick and abundant fermentation to produce the biogas, so that 80-85% of organic matter in the wastewater is effectively converted into the biogas, and the method is efficient and fast. A second-stage fermentation tank is further fermented by medium-temperature fermentation, and the organic matter in the water is fully converted into the biogas, so that the effluent of the biogas fermentation tank is improved, the organic matter content in the effluent is reduced to below 2-5%, and the reuse rate of the wastewater produced by the cellulosic ethanol is greatly improved.

Description

technical field [0001] The invention relates to the fields of environmental protection and new energy, in particular to a waste water recycling system and process method for cellulosic ethanol production. Background technique [0002] As the basis for the survival and development of modern society, energy has attracted great attention from all over the world. At present, fossil fuels such as oil, coal, and natural gas are facing the danger of resource depletion while their prices continue to rise. Moreover, the carbon dioxide and various polluting gases emitted during the production and use of fossil energy have caused varying degrees of pollution to the environment. Bioethanol has become an important alternative energy due to its environmental protection and renewable advantages. Different from the first-generation bio-ethanol that uses grain as raw material, the second-generation bio-ethanol and cellulosic ethanol use fibers such as straw, husk, bark and stem of crops as...

AI Technical Summary

Problems solved by technology

Direct discharge of waste water will not only cause serious environmental pollution, but also cause a great waste of resources

[0003] The invention patent with publication number CN 101580323A published on November 18, 2009 provides a treatment method for cellulosic ethanol production wastewater, using flocculation for cellulosic ethanol wastewater -The combined process of acid analysis-electrolytic catalytic oxidation-anaerobic fermentation can achieve the purpose of saving water and reducing sewage discharge in the production of cellulosic ethanol. Pretreatment followed by anaerobic fermentation requires a large number of pretreatment facilities, which increases investment, operating costs, and management difficulties; anaerobic fermentation uses medium temperature, and the temperature of cellulosic ethanol production wastewater is relatively high, so cooling treatment is required

Its disadvantages are: corn stalks are used as raw materials, and the pretreatment of pressure filtration and multi-effect evaporation is adopted. The liquid needs to be cooled to below 40°C before entering anaerobic fermentation, which results in high energy consumption and low biogas production capacity.

Images