Application Area

Renewables & Recycling



Almost any organic substance - whether it is organic household waste, green waste, animal excrement such as liquid manure and dung, or renewable raw materials such as corn, sugar beets, straw or grass silage - can be converted into a mixture of methane and carbon dioxide in an anaerobic fermentation process. In this process, the material called substrate is usually continuously fed into large containers where, under exclusion of air and with the help of bacteria, the decomposition into a "green gas mixture" and the so-called fermentation residue takes place in a process lasting several weeks. If the gas mixture is now purified and separated into its components using chemical or physical biogas upgrading processes, green CO2 and biomethane are obtained. The carbon dioxide can be liquefied and used for technical purposes such as cooling or purification. The biomethane, which is under low pressure after the purification process, must then be conditioned according to the rules of the "German Gas and Water Industry" and its physical properties must be adapted to the usual H- and L-gas. It can then be compressed to the nearby gas pipeline and the respective pressure level and fed into the natural gas network.


NEUMAN & ESSER offers oil-free piston compressors of the compact V-design for biomethane utilization. After cleaning and calorific value adjustment of the gas, the NEA compressor either feeds the biomethane into the natural gas grid at a final pressure of up to 90 bar or feeds the surplus natural gas back into the existing transport grid.

Compression is basically oil-free, i.e. without contamination with oil in the cylinder chamber, thus ensuring gas quality in accordance with DVGW G260, among others. The crankcase is designed to be gas-tight and pressure-resistant, so that no leakage occurs. The NEA compressor is therefore a guarantee for emission-free compression in real operation. NEA compressors also meet the local implementation regulations that apply outside Germany as well as the individual feed-in standards of the individual transport companies or energy providers.

The biogas compressor is usually rigidly installed on a level base plate, which must be vibration-decoupled from the building. Delivery options also include a compressor skid-mounted on a stable base frame. The plant components are firmly anchored to the frame, ensuring smooth running during operation.

For operators who take the aspect of environmental protection into account, NEUMAN & ESSER offers the installation in the concrete container developed by NEUMAN & ESSER – as turnkey installation on a foundation. This protects the environment from noise emissions and playfully blends in with the surroundings.

The following design specifications are fulfilled by NEA compressor units for grid feeding:

▪ DVGW worksheets G 498 and G 497 - VP 265-1

▪ HL-VO/DIN 30690

▪ D GRL 97/23/EG

▪ Ex (DVGW-HWG 442)

▪ ATEX Directive 94/9EG

▪ Ex Zone 1

Wind & Solar

The raw material used for the extraction of pure silicon, which is used in the production of microchips and solar cells, is metallurgical grade silicon, a very hard and brittle metal with a purity level of approximately 99%.  The raw silicon is chemically purified in further high-tech procedures. For that purpose, the raw silicon metal is initially ground and brought to reaction with hydrogen chloride (HCl) in a reactor.  The raw silicon and the gaseous hydrogen chloride chemically react to form trichlor-silane, a liquid clear as water.

The trichlorsilane is distilled, separating the impurities in it.  Through great energy expenditure, the high-purity liquid extracted is transformed into the purest polysilicon, polycrystalline silicon, which is then poured in a block.  This transformation takes place in the trichlorsilane process.  In the process, a gaseous mixture of trichlorsilane and hydrogen is discharged into a quartz crucible.  Pure silicon and hydrogen chloride are produced at approximately 1,200°C.

A so-called bridge composed of thin silicon rods is found in the quartz crucible, onto which the elemental silicon condenses in polycrystalline form.  These rods can grow up to 300 mm in diameter.

NEA compressors are used in this process to prepare the gas mixture generated in the reaction for the fol- lowing purification, which means increasing the pressure up to approx. 17 bar.  In the gas processing plant, the chlorosilane remnants are first precipitated and then the hydrogen and hydrogen chloride are separated so that they may then be fed into the circulation again.

NEA compressors are in operation at almost all leading polysilicon manufacturers. The most common type is the single-stage TES130, ZS130, DS130 and DS190, which are mostly produced as series.

Material Separation

The separation, processing and reuse of material flows is becoming increasingly important in a responsible society. In order to implement these processes in the most energy-efficient and environmentally friendly way possible, NEA offers mechanical solutions for grinding and separating various materials. The separation units used, such as the GRC guide ring classifier, take advantage not only of the different grindability and resulting particle size of the various raw materials, but also in particular of the differences in the specific density of the individual components of the material mixture.

In this way, for example, graphite can be re-extracted from recycled batteries, or pollutants such as heavy metals can be removed from the residues of used catalysts. Recovered Carbon Black (rCB) is obtained from end-of-life tires, for example.


In the course of decarbonization, renewable resources such as biomass are becoming increasingly important. Biomass to X, also Bio-to-X (BtX), refers to all technologies for converting biomass into electricity, heat or other storable energy carriers. The conversion of biomass can take place via thermal-chemical, biochemical or physical-chemical methods. In addition to electricity and heat, the products include hydrogen, biofuels and various chemicals.

Biomass is produced i.e as a residual material in forestry and agriculture or in food production. BtX usually involves multi-stage processes in which an intermediate product such as biogas, syngas or ethanol is first produced by conversion. This is followed by a further processing step, such as steam reforming in the case of hydrogen production from biogas.