Engineering Concept of PGMCC Technology for Plasma Conversion of Municipal Solid Waste, Industrial Waste and Biomass into Methane, Hydrogen and Other Valuable Products

Authors: Lazar Potashnyik — Int-Energia Kft., Hungary;  Arian Mamayenko — Metaplasma S.L., Spain

Abstract

PGMCC®[1] technology is designed for integrated processing of municipal solid waste, industrial solid waste and biomass. The process is based on Plasma Gasification and Melting (PGM), using water vapour as the plasma-forming gas. The organic fraction of the prepared feedstock is converted into pyrolysis gas, while the inorganic fraction forms a mineral melt. Within PGMCC®, the downstream gas purification and chemical conversion system prepares gas streams, captures and utilises CO₂, and produces methane or hydrogen. Hydrogen for methane synthesis is generated within the process, without an electrolyser. Detailed engineering documentation covers equipment processing 100 kg/h of dry feedstock, with scale-up and material and energy balances calculated for methane and hydrogen modes at 1,000 kg/h. These results support site-specific plant engineering. In addition to methane production, the Sabatier–WGS reactor design allows a transition to hydrogen production by replacing catalytic cartridges.

1. Scope of Application and Process Products

PGMCC® processes municipal solid waste, industrial solid waste and biomass, which differ in moisture, ash content, elemental composition and particle size. The process includes feedstock preparation, plasma processing, pyrolysis gas purification and conversion.

The principal product is purified methane for electric power and heat generation or gas-network injection, subject to quality requirements. Other products include vitrified slag and carbonates obtained through CO₂ fixation.

2. Experimental Basis of PGM and the Use of Steam Plasma

Zhang et al. [1, 2] investigated municipal solid waste gasification and melting in a PGM reactor. Unlike PGMCC®, their configuration used air as the plasma-forming medium and separately supplied steam for gasification.

PGMCC® uses water vapour as the plasma-forming gas, avoiding nitrogen ballast from plasma-forming air and enabling hydrogen-containing pyrolysis gas. Plasma torch and steam-preparation energy demands are included in the energy balance. Independent steam-plasma studies [3, 4] use different operating conditions.

In the PGMCC® plasma reactor, thermochemical conversion of waste takes place in a high-temperature steam environment without the supply of air or free oxygen. Unlike combustion processes, the principal mechanisms of organic matter conversion are thermochemical decomposition and steam gasification under predominantly reducing conditions. This process arrangement suppresses the formation of dioxins and furans in the reaction zone, while subsequent rapid quenching of the pyrolysis gas by spray nozzles inhibits their re-formation.

3. Integrated PGMCC® Gas Purification and Conversion System

PGMCC® gas purification also underpins a system for methane-containing gases, including biogas. Both applications use similar purification and captured-component handling principles, with conditions and equipment adapted to inlet gas composition.

The system provides multistage removal of impurities, including acidic components, particulates and substances that interfere with subsequent catalytic processing. Depending on the configuration, reactive absorption, catalytic treatment and final adsorption purification are used. Captured CO₂ is chemically bound to produce useful carbonate products. Regeneration of process media, recovery of heat from exothermic reactions and recycling of valuable components recovered from gas streams are provided for. PGMCC® also provides for the return of methane recovered from residual gas streams to the process, reducing losses of the target product.

Methanation uses hydrogen generated within the PGMCC® process, without an external electrolyser. The principal reactions involved are:

CO₂ + 4H₂ → CH₄ + 2H₂O and CO + H₂O ⇌ CO₂ + H₂

Equipment sequence, operating conditions and recycles are defined in PGMCC® engineering documentation. Replaceable Sabatier–WGS catalytic cartridges allow switching the target product between methane and hydrogen. Hydrogen conditioning and purification depend on operating mode and intended use.

PGMCC® combines high-efficiency gas purification, reduced component losses and CO₂ utilisation. Depending on the operating mode, K₂CO₃, KHCO₃ and CaCO₃ may be produced; their commercial specifications depend on composition and intended use.

4. Feedstock Preparation and Vitrified Slag

The ability to process heterogeneous municipal and industrial waste and biomass is primarily ensured by feedstock preparation. Vacuum thermal drying is provided for wet streams; the design considers initial moisture content of up to 80%, subject to appropriate pretreatment. This figure characterises incoming feedstock, not the moisture content of the material fed directly into the plasma reactor. Specific applicability depends on the morphological and chemical composition of municipal and industrial solid waste and biomass.

Inorganic constituents melt in the PGMCC® reactor and cool into a basalt-like vitrified slag. Its glassy structure promotes heavy-metal immobilisation and reduced leachability, consistent with published waste-melting research [6].

The chemical composition of vitrified slags obtained from plasma processing of municipal solid waste was investigated by the accredited laboratory of the Radon Moscow Scientific and Industrial Association in 2008–2009 [7, 8], and by the Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences in 2009 [9]. The analyses confirm a predominantly silicate-oxide composition of the materials examined. A technical assessment of their potential use in mineral insulation production yielded calculated acidity moduli of 4.05 and approximately 2.04 for two slag samples [9], meeting the raw-material suitability criteria for mineral wool production cited in that study.

Vitrified slag may be used in the production of building materials and mineral insulation, in road construction, or as a filler, provided that its properties meet the applicable standards.

5. Material and Energy Balances

Equipment was scaled to 1,000 kg/h dry feedstock; material and energy balances were calculated for methane and hydrogen modes to support equipment selection and operating specifications.

Material balances include feedstock, moisture, steam, reagents, methane, condensate, mineral and carbonate products, and separated impurities. Carbon, hydrogen and oxygen balances link plasma processing to downstream conversion. Energy calculations cover plasma torches, steam generation, preparation, compression, cooling, purification and catalysis, with potential heat recovery.

A comparison of the calculated output indicators for the two modes at 1,000 kg/h of dry municipal solid waste is presented in Table 1.

Table 1

Indicator	Methane mode	Hydrogen mode
Dry feedstock, kg/h	1,000	1,000
Main gaseous product	CH₄	H₂
Calculated output of main gaseous product, kg/h	361–447	157.9
H₂ output, Nm³/h[2]	—	≈ 1,760

Source of figures: PGMCC® proprietary engineering calculations for methane and hydrogen operating modes.

These balances support plant design; actual resource consumption and product yields depend on assumed feedstock composition and site-specific conditions.

6. Industrial Implementation and Scale-Up

Engineering documentation for 100 kg/h equipment and scaling to 1,000 kg/h support detailed site-specific design. Further engineering covers the master plan, civil works, layout, utilities, automation, safety and environmental protection under local regulations.

PGMCC® integrates waste and biomass processing, controlled-quality methane production, CO₂ utilisation, vitrified slag formation and heat recovery. Its gas-purification technology can also serve other methane-containing gases in a stand-alone system.

A related methane-containing gas purification installation underwent practical tests in Spain with Bureau Veritas participation. Gas composition, methane and potassium carbonate yields, and energy parameters were recorded using developer-supplied data.

Figure 1. Experimental biogas purification installation in Spain, developed on the technological basis of PGMCC® and independently inspected by Bureau Veritas.

7. Example of Industrial Scale-Up of PGMCC® in Methane Production Mode

The scale-up example considers a PGMCC® complex comprising five parallel methane production lines. Each line processes 1,428.57 kg/h of wet waste at 30% moisture, equivalent to 1,000 kg/h of dry waste before separation. The material balance is based on the characteristics of municipal solid waste from one region of Germany. The total complex throughput is 5,000 kg/h of dry waste, or approximately 7,143 kg/h of wet waste.

Figure 2 shows calculated flows for one PGMCC® line: feedstock preparation, steam-plasma gasification, primary purification, methanation, CO₂ removal, drying and methane delivery, including gas and condensate recycles, reagents and potassium carbonate.

According to the adopted material balance, one process line has a calculated product methane output of 446.72 kg/h, while the five-line complex produces 2,233.60 kg/h. Consumption of 50% KOH solution is 3,670.38 kg/h per line, and the calculated output of 50% K₂CO₃ solution is 4,471.63 kg/h. The total external material balance for one line is 5,399.19 kg/h for both input and output streams.

Conclusions

PGMCC® is an integrated engineering solution for plasma conversion of municipal solid waste, industrial solid waste and biomass into methane or hydrogen and useful mineral products. The process combines feedstock preparation, plasma gasification using water vapour as the plasma-forming gas, cooling and purification of the resulting gas, subsequent catalytic conversion and utilisation of captured CO₂. The engineering documentation developed for equipment processing 100 kg/h, the scale-up of process solutions to 1,000 kg/h, and the calculated material and energy balances provide an engineering basis for further design of industrial PGMCC® complexes. The Sabatier–WGS reactor design provides for selection of methane or hydrogen as the target gaseous product through replacement of catalytic cartridges.

Based on the characteristics of municipal solid waste from a region in Germany, calculations were performed for a PGMCC® industrial complex comprising five process lines with a total throughput of 5,000 kg/h of dry feedstock. The calculated output of product methane is 2,233.60 kg/h. The resulting material and energy balances confirm the feasibility of scaling up the technology on a calculated basis and provide a foundation for further engineering of the industrial complex, taking into account feedstock composition and site-specific conditions.

References

[1] Zhang Q. et al. Gasification of municipal solid waste in the Plasma Gasification Melting process. Applied Energy 90 (2012), 106–112. DOI: 10.1016/j.apenergy.2011.01.041.

[2] Zhang Q. et al. Performance analysis of municipal solid waste gasification with steam in a Plasma Gasification Melting reactor. Applied Energy 98 (2012), 219–229. DOI: 10.1016/j.apenergy.2012.03.028.

[3] Rutberg P. G., Kuznetsov V. A., Serba E. O., et al. Novel three-phase steam–air plasma torch for gasification of high-caloric waste. Applied Energy. 2013. Vol. 108. P. 505–514. DOI: 10.1016/j.apenergy.2013.03.052.

[4] Jothiprakash G., Sundararaju P., Subburamu K., et al. Plasma gasification of agro-residues for syngas production: process optimization and system performance. Waste Disposal & Sustainable Energy. 2026. Vol. 8. P. 533–545. DOI: 10.1007/s42768-026-00289-y.

[5] Int-Energia Kft. PGMCC® — developer materials: https://int-energia.com/solutions/.

[6] Jung C. H., Matsuto T., Tanaka N. Behavior of metals in ash melting and gasification-melting of municipal solid waste (MSW). Waste Management. 2005. Vol. 25, No. 3. P. 301–310. DOI: 10.1016/j.wasman.2004.08.012.

[7] Radon Moscow Scientific and Industrial Association. Chemical analysis report No. 1/8-2008 on vitrified slags obtained from plasma processing of municipal solid waste. 24 November 2008. Samples P-1 to P-4. Laboratory report.

[8] Radon Moscow Scientific and Industrial Association. Chemical analysis report No. 1/15-2009 on vitrified slags obtained from plasma processing of municipal solid waste. 8 October 2009. Samples ShP 16-7, ShP 16-8 and ShP 16-10. Laboratory report.

[9] Evaluation of a Possibility of Using Vitrified Slag for Manufacturing Heat Insulation Material. Technical Note. With appended results of vitrified slag analyses by the Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, dated 9 December 2009, and acidity modulus calculations. Technical document.

[1] PGMCC® (Plasma Gasification and Melting with Carbon Capture) — technology for plasma gasification and melting of municipal and industrial solid waste and biomass, followed by CO₂ capture and utilization to produce methane or hydrogen and other useful products.

[2] Nm³ — gas volume expressed at normal conditions: a temperature of 0 °C and an absolute pressure of 101.325 kPa.