Modern Ruminant Livestock Paradigm: Reducing Methane Production and Increasing Feed Efficiency

The gases in the atmosphere that can capture the sun's heat are called greenhouse gases (GHG). Which includes greenhouse gases in the atmosphere, among others, are carbon dioxide (CO2), nitrogen dioxide (N2O), methane (CH4), and freon (SF6, HFC and PFC). Methane gas (CH4) is a dangerous gas for the earth's atmosphere and one of the greenhouse gas groups above because of the destructive power of methane gas 21 times carbon dioxide (CO2). This requires efforts to prevent methane gas and reduce its production. An example is the use of POME waste or palm oil mill effluent for biogas production. In this way, methane occurring in the open air (aerobic) will be avoided (methane avoidance scenario) and will not be released into the atmosphere with the biogas unit. The livestock sector also has the potential to produce, namely the group of ruminant farms or ruminant animals. The methane is produced in the ruminant's rumen as part of the digestion process. It is estimated that the contribution of methane from ruminant livestock is dominant and of course it needs to be reduced. The production of methane gas (CH4) besides being an environmental problem also causes a lot of energy loss in livestock. And it turns out that there is a process of reducing methane production which simultaneously improves health and increases body weight and milk production.

Large ruminant farms should be more aware of this condition and have a greater incentive to reduce methane production. Biochar is a feed supplement that can be used for the above purposes. The use of 1-3% biochar from dry feed ingredients has been shown to significantly increase body weight gain in beef cattle, as well as milk production in dairy cows. Experiments in Australia on beef cattle for 2 months have given a weight gain of 10% compared to those who do not use biochar. As for dairy cows, it has provided a profit of $ 70,000 per year. For more details, read here. Meanwhile, the reduction in methane gas emissions is estimated at 29% from the use of biochar. Once paddle 2-3 islands, so the saying goes.

Another effect of using biochar as a feed additive is that livestock manure becomes denser and less smelly. Biochar can also be used alone to deal with the smell and viscosity of livestock manure, so that the cage becomes cleaner and does not smell strong. In addition, if the manure is used for production, the biogas production will also increase, for more details, please read here. The composted digestate will also produce better organic fertilizer (compost) because of the additional biochar.

The quality of biochar is also very important, especially for animal feed supplements. Meat and milk are livestock production to meet human food needs, so that it will also affect humans in the end. The quality of biochar is determined by the raw materials used and the production process carried out. This indicates that not all biochar has the same quality, for example biochar from agricultural wastes with high ash content with traditional processes, with wood biomass raw materials with a small ash content and modern processes, of course the results are different, for example using the same modern technology will have different results. The differences mainly lie in their physical chemistry properties.

Biochar production should also be designed according to its objectives, for example the biochar feed supplement above must use selected biomass raw materials and modern processes so that the quality is stable and maintained. Meanwhile, the reference for biochar quality can be OMRI, USDA or IBI. World feed livestock associations or organizations such as FEFAC, IFIF and AFIA are currently very concerned about safety and sustainability, so this can be in line with biochar as a feed additive. Biochar as a feed additive, especially dairy cattle, has been accepted by almost all European Union countries. Meanwhile, for purposes such as reducing odors and the dilution of impurities, biochar is produced from any biomass and even by using simple technology (low tech).

Why Produce Electricity From Biogas Using Gas Engine Generators? Not With Gas Turbine Generators Or Steam Turbine Generators

  

The need for this type of power plant is always related to capacity, a number of technical factors and the investment costs required. Turbine with generator is a type of generator which is commonly used in industry, especially steam turbine and gas turbine. The grouping of turbine types above is based on the principle of operation and the fluid that moves them. At a palm oil mill, almost all of the electricity is generated from a steam turbine generator. In addition to electricity production, the steam generated from the boiler is also used to process fresh fruit bunches (FFB) to produce crude palm oil or CPO.

Processing of palm oil mill effluent (POME) into biogas and subsequently mostly used for power generation. Almost all of the electricity from biogas is used to meet the needs outside the palm oil mill and the surrounding community. With the potential for palm oil mills in Indonesia that are estimated at more than 1000 units supported by 15 million hectares of palm oil plantations, the potential for electricity generated will be more than 1.5 GW. Approximately 0.7 m3 of liquid waste is produced by the palm oil mill from each tonne of FFB processed. Biogas usually consists of 50-75% methane (CH4), 25-45% carbon dioxide (CO2), and a number of other gases. If wastewater management is not controlled, methane in biogas is released directly into the atmosphere. As a greenhouse gas (GHG) methane has a 21 times greater effect than CO2. The production of electricity from biogas from palm oil mill effluent (pome) is also an effort to reduce environmental hazards. The electricity production from the biogas all uses a gas engine generator and none of them uses a steam engine generator. This is because the production of electricity with steam turbines is not only more complex but also less efficient. The gas engine generator is a power plant that is most suitable for the conversion of biogas to electricity. Gas engines whose engines are similar to gasoline engines, with only the change of fuel into gas (biogas) or similar to vehicle engines such as public buses that run on gas fuel are also more familiar to most people. 

Gas turbine generators are generally used for large capacity power plants. Gas power plants in Indonesia generally use gas turbine generators. Gas turbines are equipment that uses high pressure combustion gases to turn a turbine that can be connected to a generator to generate electricity. Apart from generating power, gas turbines are also used in boats, racing cars and jet planes. The main parts of gas turbines include: compressor, combustion chamber, gas turbine and workload. Each part or segment has a number of critical components which are connected in one axis. During the operation of the gas turbine, some of the power generated by the turbine is used to drive the compressor. The large capacity and technical factors of gas turbine generators make the unit expensive and not used for the production of electricity from biogas. The electricity capacity of biogas from wastewater treatment like POME is not too large, that is, for a palm oil mill with a capacity of 30 tonnes / hour of FFB it will produce about 1 MW of electricity and its multiples. This is the reason why gas engine generators are used in biogas power plants, especially in the palm oil industry.

Urgency of the Biogas Unit in the Palm Oil Mills

In palm oil mills with a big vision, business development is important and always receives special attention. Palm oil mills which generally only produce CPO (crude palm oil) and only a few produce PKO (palm kernel oil). Biomass wastes generated such as empty fruit bunches (EFB), fiber and palm kernel shells (PKS) have great potential to be developed into businesses. In addition, the kernel (palm kernel) which has only been sold to other parties can actually be processed by ownself into a PKO. Even CPO itself can also be developed into various derivative products such as cooking oil, stearin, olein and various other oleochemical products. To process the above material, will always need energy and the availability of energy especially those which become a major obstacle to various business developments in the palm oil mill.

Biogas from POME or palm oil mill effluent is a potential energy source that can be created to support a number of business developments based on the palm oil mill. Liquid waste in the form of POME is generally not utilized and is still a problem for most palm oil mills today. By processing it into biogas, it can then be converted to heat and electricity so that it can be utilized for business development that mentioned above. Under certain conditions the biogas produced can even be upgraded to CBG (Compressed Biomethane Gas) with the use as a substitute for fuel in trucks used in the palm oil industry.

There are two types of biogas reactors being developed at this time, namely by maing then covering the pool with a special rubber material (covered lagoon) and a continous stirred tank reactor (CSTR). Although it requires a wider area, the type of covered lagoon is more widely used because in addition to being simpler it can also accommodate more biogas volume. A palm oil mill using centrifugal oil separator will produce a lot of sludge which increases the COD (Chemical Oxygen Demand) thereby increasing the amount of biogas produced. While palm oil mills use decanters, the sludge will be separated so that the COD is low and so is the biogas product produced.

Biogas Water Absorber

The use of biogas to convert to thermal energy (in external combustion engines such as furnaces and boilers) is simpler than the conversion to electrical energy with a gas engine (typical of internal combustion engine). When biogas is converted into heat, the gas purification process is not even carried out and directly burned in the gas burner, so existing boiler of the palm oil can be used. But when it converted into electricity with a gas engine , the biogas purification process becomes important, because the quality of the gas is very influential on the performance and durability of the gas engine and automatically the electricity product produced. Biogas with a lot of H2S content will be corrosive so as to damage the gas engine unit and biogas with high CO2 content will reduce the calorific value so that the gas engine performance will decrease.