How to achieve the efficiency of the biogenerator. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

How to achieve the efficiency of the biogenerator. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Alternative energy sources

Comments on the article

For the efficient operation of a biogas plant, in addition to a strictly anaerobic environment, a number of requirements will have to be met. First, to maintain optimal temperature and acid conditions in the reactor. Secondly, to constantly monitor the presence of nutrients in the fermented medium, ensuring a low content of inhibitor substances in this medium, that is, substances that prevent the vital activity of microorganisms.

In fact, the formation of methane occurs in a fairly wide range of temperatures (8-60°C), while certain types of bacteria participate in the fermentation process at certain temperatures.

Three characteristic temperature levels are usually distinguished, which are preferred for certain types of bacteria. Psychrophilic mode is at a temperature of 8-20°C, mesophilic - at 30-40°C, thermophilic - at 45-60°C. More productive thermophilic and mesophilic modes of fermentation, however, all three modes have both their advantages and disadvantages. Modes with higher temperatures require more energy to maintain the optimum temperature, but by reducing the duration of digestion, it is possible to significantly reduce the volume of the bioreactor and thus increase the productivity of the biogas plant.

However, in practice, maintaining high temperatures in biomass is often associated with high energy costs for heating and thermoregulation of bioreactors, which in turn significantly increases the cost of biogas production. Thus, the cost of energy required to heat the contents of the fermentation chamber in thermophilic fermentation is so great that it exceeds any benefits associated with faster fermentation than in other cases. It follows that only mesophilic (30-40°C) or psychrophilic (8-20°C) methane fermentation is of practical importance in household conditions.

For the normal course of fermentation, a slightly alkaline reaction of the medium is necessary (pH = 6,7-7,6). With optimal (smooth) activity of acid-forming and methane bacteria (that is, with a steady fermentation process), the pH value is maintained within the desired limits "automatically". However, sometimes acid-forming bacteria begin to multiply faster than methane ones, due to which the concentration of volatile fatty acids in the fermentation chamber increases and so-called "acidification" occurs, as a result of which the biogas yield decreases and the acidity of the biomass increases. In this case, hot water, milk of lime, soda should be added to the contents of the bioreactor. If the balance between nitrogen and carbon is disturbed, it is restored by adding cow urine to the biomass.

The basis for the unhindered reproduction of anaerobic bacteria is, of course, the presence of nutrients in the fermented medium. And almost all the nutrients necessary for the growth of methane bacteria are contained in animal excrement, which is the main raw material for the production of biogas. The diversity of the species composition of methane-forming bacteria allows the use of almost all types of liquid and solid organic waste. But the best organic mass for biogas production is cattle manure mixed with plant residues (biomass moisture content is not less than 85-90%).

The fermented organic mass should not contain substances (antibiotics, solvents, etc.) that adversely affect the vital activity of microorganisms. Some non-organic substances do not contribute to the "work" of microorganisms, therefore, for example, water left after washing with synthetic detergents cannot be used to dilute manure.

Biogas production also depends on many other factors. For example, a floating crust periodically forms on the surface of the organic mass, interfering with the release of biogas. Therefore, it must be eliminated by stirring the contents of the bioreactor 1-2 times a day. Stirring also contributes to a uniform distribution of temperature and acidity in the biomass in the digestion chamber.

For the complete decomposition of organic matter, as a rule, it takes a long time. And at the same time, the duration of fermentation, taking into account the rate of decomposition inherent in this type of waste, depends on the required degree of decomposition of organic matter. Usually, the maximum yield of biogas and the best quality fertilizers are observed with the decomposition of organic matter (manure) up to 30-33%. Note that when the biomass stays in the bioreactor for 14-15 days, the completeness of its decomposition is 25%.

With a continuous method of digestion, when a certain volume of "spent" organic matter in the reactor is unloaded simultaneously with the loading of the same volume of fresh material, the largest amount of biogas is released, and with such an organization of the process for small-sized biogas plants in household plots, the dose of daily loading usually does not exceed 4 -5% usable volume of the fermentation chamber.

Author: Shomin A.A.

See other articles Section Alternative energy sources.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Alcohol content of warm beer 07.05.2024

Beer, as one of the most common alcoholic drinks, has its own unique taste, which can change depending on the temperature of consumption. A new study by an international team of scientists has found that beer temperature has a significant impact on the perception of alcoholic taste. The study, led by materials scientist Lei Jiang, found that at different temperatures, ethanol and water molecules form different types of clusters, which affects the perception of alcoholic taste. At low temperatures, more pyramid-like clusters form, which reduces the pungency of the "ethanol" taste and makes the drink taste less alcoholic. On the contrary, as the temperature increases, the clusters become more chain-like, resulting in a more pronounced alcoholic taste. This explains why the taste of some alcoholic drinks, such as baijiu, can change depending on temperature. The data obtained opens up new prospects for beverage manufacturers, ... >>

Major risk factor for gambling addiction 07.05.2024

Computer games are becoming an increasingly popular form of entertainment among teenagers, but the associated risk of gaming addiction remains a significant problem. American scientists conducted a study to determine the main factors contributing to this addiction and offer recommendations for its prevention. Over the course of six years, 385 teenagers were followed to find out what factors may predispose them to gambling addiction. The results showed that 90% of study participants were not at risk of addiction, while 10% became gambling addicts. It turned out that the key factor in the onset of gambling addiction is a low level of prosocial behavior. Teenagers with a low level of prosocial behavior do not show interest in the help and support of others, which can lead to a loss of contact with the real world and a deepening dependence on virtual reality offered by computer games. Based on these results, scientists ... >>

Traffic noise delays the growth of chicks 06.05.2024

The sounds that surround us in modern cities are becoming increasingly piercing. However, few people think about how this noise affects the animal world, especially such delicate creatures as chicks that have not yet hatched from their eggs. Recent research is shedding light on this issue, indicating serious consequences for their development and survival. Scientists have found that exposure of zebra diamondback chicks to traffic noise can cause serious disruption to their development. Experiments have shown that noise pollution can significantly delay their hatching, and those chicks that do emerge face a number of health-promoting problems. The researchers also found that the negative effects of noise pollution extend into the adult birds. Reduced chances of reproduction and decreased fertility indicate the long-term effects that traffic noise has on wildlife. The study results highlight the need ... >>

Random news from the Archive

Motion sickness watch 05.02.2001

A watch-like wrist device is manufactured in the USA and serves as a remedy for seasickness.

According to the manufacturer, Woodside Biomedical, the device stimulates with a weak electric current an active point on the skin of the wrist, irritation of which relieves dizziness and nausea. This point was known to ancient Chinese doctors and is still used in the practice of acupuncture.

The miniature battery lasts for 48 hours of continuous operation.

Other interesting news:

▪ Expanding the capabilities of the GSM / GPRS modem MAESTRO 100

▪ Robot vacuum cleaner for an apartment

▪ Lynx perfume

▪ Jawbone UP electronic bracelet keeps track of your health

▪ A quantum computer that does not use qubits

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Signal limiters, compressors. Article selection

▪ article Yes, vaudeville is a thing, but everything else is rotten. Popular expression

▪ article In which sport the rules have remained unchanged for more than two millennia? Detailed answer

▪ article The driver of the car UAZ-2206. Standard instruction on labor protection

▪ article A good crystal filter for CW and AM. Encyclopedia of radio electronics and electrical engineering

▪ article Powerful FET switch, 20 amps. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews