5. The state of design and construction of the shaft reactor for waste treatment plant based on plasma-steam-oxygen technology

#### 5.1. Features of the project

index of the energy efficiency of the gasification equipment are valid up to 17% of the mineral

A more rigorous problem of the non-stoichiometric gasification regime, self-consistent with respect to energy consumption, is also considered. It was solved on the basis of varying the values of L in the reaction (21) for a given value of K. The value of L was determined at which the compensation of the emerging thermal energy deficit ΔQ is attained due to the energy of the plasma jet introduced with the indicated quantity K of water steam at a certain enthalpy. In other words, it was determined at which values of L the condition ΔQ(L) – QPL = 0 is reached. The main regularities, which ultimately represent the efficiency of the non-stoichiometric gasification process with a small enthalpy of HPL = 0.72 kWh/kg of the plasma jet and in its

Figure 4. The main regularities characterizing the energy efficiency of non-stoichiometric modes of sewage sludge gasification as a function of the amount of water vapor K introduced into the reaction with the enthalpy of the plasma jet HPL = 0.72 kWh/kg (a), and also, in its absence, for wet sewage sludge (b): 1—the oxygen content L introduced into the reactor; 2—additional energy ΔQ, which should be introduced into the volume to reach the operating temperature, equal to the energy introduced by the steam-plasma jet QPL (the latter—with the exception of wet sewage sludge); 3—the energy of the syngas WSG\*; 4—coefficient of nonstoichiometrykNS; 5a and 5b—energy consumption for the production of oxygen

, respectively; 6a and 6b—energy efficiency index of the process at the

content in sewage sludge to be vitrified.

182 Gasification for Low-grade Feedstock

at a specific consumption of 0.35 and 1 kWh/Nm3

indicated energy inputs for the production of oxygen, respectively.

absence, that is, for wet bottom sludge are shown in Figure 4.

In 2017, the Institute of Gas of the National Academy of Sciences of Ukraine completes the execution of the state order for development of steam-plasma technology for the processing of sewage sludge with the support of the Ministry of Education and Science of Ukraine. The result will be a reactor module for waste treatment based on plasma-steam-oxygen technology, which can become the core of plants for the recycling of hazardous waste: bottom sediments of aeration stations of urban water purification systems, unsorted solid household wastes (they are dangerous because of the risk of entering into their composition of chlorinated compounds), medical waste, overdue pesticides and chemical treatments for plants, etc. The module is designed in such a way as to ensure its payback through the production of electrical energy through the products of gasification of carbon compounds in the waste. At the heart of the implementation of this project lie precisely the above calculations.

Unlike the previous development [9], the peculiarity of this shaft reactor is the loading of raw materials through its side wall. This will allow, on the one hand, to comply with the operating mode of the reactor, which meets the requirements of the Directive 2000/76/EC [15] for the processing of chlorine-containing waste. On the other hand, the operation of the PT will contribute to the achievement of the temperature regime characteristic for the vitrification of the ash residue, thus solving the problem of handling wastes containing heavy metals. The reactor capacity will be up to 500 kg/h depending on the type of waste. In terms of annual capacity, this will be up to 4000 tons per year, based on the 11-month cycle of work. The reactor will be tested this year, completely with equipment previously developed as part of a medical waste treatment plant [9]. The general view of the reactor of this plant is shown in Figure 5.

Researchers of LEI are also projecting a novel plasma volume reactor (Figure 6) to create steady non-transferred plasma ambient. It will allow the destruction wide range of hazardous substances.

The primary shield of the reactor is made up of steel (1500 mm of height 1500 mm of width) with high temperature ceramic inner lining. Initially, it has hopper for waste feeding with single door arrangement. The door operation is manual. The chamber has several ports, 350 mm above the bottom of the chamber for mounting air or nitrogen PT. It is expected the plasma arc reactor have very high destruction efficiency and will be very robust. It is considered that it will be able to treat any waste with minimal or no pretreatment and produce a single waste form as gas and slag. The designed arc reactor has carbon anode and will strike an arc in a bath of molten slag. The higher temperatures will be reached by the arc convert the organic waste into light organics and primary elements. The system is under further development.

Youngchul Byun et al. [7], in terms of present value to the daily capacity of the reactor 12 TPD, this is noticeably less. The latter is due to the low cost of labor in present-day Ukraine. The estimates obtained in this article make it possible to compare its economic indicators with other developments presented in the Ukrainian market, among them, Waste-to-Energy Plant "Energy-2" from Brno [34], Integrated Multifuel Gasification technology (IMG) of Bellwether Recuparative Gasification Ltd. [35] and Westinghouse Plasma Corporation [36]. Table 7 shows the main technical and economic indicators that characterize the operation of these plants according to the references given. These include: C—annual capacity of equipment (t/a), P power generation of electricity to consumers per year (MW∙h/a), I—investments. As can be

C, t/a 224,000 100,000 534,000 4000 P, MW∙h/a 63,000 68,000 427,000 4200

I/C, USD(€)/t 580 650 575 300 P/C, kW∙h /t 240 680 800 1050 Payback (in the absence of operating costs), years 61.9 28.7 20 8

I, USD(€) 130 mln. € 65 mln. € 307.5 mln. USD 1.2 mln. USD

Table 7. Comparison of the main technical and economic indicators of some waste-processing plants in Ukraine (see

"Energy-2" [34] IMG [35] WPC [36] IG NASU (project,

Efficiency of Plasma Gasification Technologies for Hazardous Waste Treatment

http://dx.doi.org/10.5772/intechopen.74485

185

this paper)

Figure 6. Plasma arc reactor. 1—Plasma torch; 2—Metallic shield; 3—Lining alloy; 4—Graphite plate; 5—Circular chan-

nel; 6—Observation window.

explanation in the text).

Indicator Technology

#### 5.2. Economic assessments

Estimated construction cost of the plant for processing hazardous waste using the proposed reactor module will be about 1.2 million USD. If we compare it with the data of the publication

Figure 5. The reactor module body for plasma-steam-oxygen waste treatment in the stage of its installation.

energy through the products of gasification of carbon compounds in the waste. At the heart of

Unlike the previous development [9], the peculiarity of this shaft reactor is the loading of raw materials through its side wall. This will allow, on the one hand, to comply with the operating mode of the reactor, which meets the requirements of the Directive 2000/76/EC [15] for the processing of chlorine-containing waste. On the other hand, the operation of the PT will contribute to the achievement of the temperature regime characteristic for the vitrification of the ash residue, thus solving the problem of handling wastes containing heavy metals. The reactor capacity will be up to 500 kg/h depending on the type of waste. In terms of annual capacity, this will be up to 4000 tons per year, based on the 11-month cycle of work. The reactor will be tested this year, completely with equipment previously developed as part of a medical waste treatment plant [9]. The general view of the reactor of this plant is shown in Figure 5.

Researchers of LEI are also projecting a novel plasma volume reactor (Figure 6) to create steady non-transferred plasma ambient. It will allow the destruction wide range of hazardous

The primary shield of the reactor is made up of steel (1500 mm of height 1500 mm of width) with high temperature ceramic inner lining. Initially, it has hopper for waste feeding with single door arrangement. The door operation is manual. The chamber has several ports, 350 mm above the bottom of the chamber for mounting air or nitrogen PT. It is expected the plasma arc reactor have very high destruction efficiency and will be very robust. It is considered that it will be able to treat any waste with minimal or no pretreatment and produce a single waste form as gas and slag. The designed arc reactor has carbon anode and will strike an arc in a bath of molten slag. The higher temperatures will be reached by the arc convert the organic waste into

Estimated construction cost of the plant for processing hazardous waste using the proposed reactor module will be about 1.2 million USD. If we compare it with the data of the publication

Figure 5. The reactor module body for plasma-steam-oxygen waste treatment in the stage of its installation.

light organics and primary elements. The system is under further development.

the implementation of this project lie precisely the above calculations.

substances.

184 Gasification for Low-grade Feedstock

5.2. Economic assessments

Figure 6. Plasma arc reactor. 1—Plasma torch; 2—Metallic shield; 3—Lining alloy; 4—Graphite plate; 5—Circular channel; 6—Observation window.

Youngchul Byun et al. [7], in terms of present value to the daily capacity of the reactor 12 TPD, this is noticeably less. The latter is due to the low cost of labor in present-day Ukraine. The estimates obtained in this article make it possible to compare its economic indicators with other developments presented in the Ukrainian market, among them, Waste-to-Energy Plant "Energy-2" from Brno [34], Integrated Multifuel Gasification technology (IMG) of Bellwether Recuparative Gasification Ltd. [35] and Westinghouse Plasma Corporation [36]. Table 7 shows the main technical and economic indicators that characterize the operation of these plants according to the references given. These include: C—annual capacity of equipment (t/a), P power generation of electricity to consumers per year (MW∙h/a), I—investments. As can be


Table 7. Comparison of the main technical and economic indicators of some waste-processing plants in Ukraine (see explanation in the text).

seen, the traditional waste-processing plant [34] "Energy-2" requires specific investments I/C, close to the plasma technologies [35, 36]. On the contrary, it has the worst indicators P/C concerning the possibility of investment return due to the production of additional electric energy for external consumers. All three samples of technologies [34–36] have a very high cost; it cannot be compensated by production of additional electric energy. Some additional reduction of payback is achieved by the presence of a "green tariff" in Ukraine for electric energy.

Author details

References

Victor Zhovtyansky<sup>1</sup> and Vitas Valinčius2

tute. 2000;78(4):157-171

2003;45:957-969

2008. pp. 465-468

\*Address all correspondence to: vitas@mail.lei.lt

2 Lithuanian Energy Institute, Kaunas, Lithuania

Material Processes. 2009;13(3–4):299-313

InTechOpen; 2012. pp. 183-210

on Plasma Science. 2013;41(12):3233-3239

\*

Efficiency of Plasma Gasification Technologies for Hazardous Waste Treatment

http://dx.doi.org/10.5772/intechopen.74485

187

1 Institute of Gas of the National Academy of Sciences of Ukraine, Kyiv, Ukraine

[1] Gorokhovski M, Karpenko EI, Lockwood FC, Messerle VE, Trusov BG, Ustimenko AB. Plasma technologies for solid fuels: Experiment and theory. Journal of the Energy Insti-

[2] Rutberg PG. Plasma pyrolysis of toxic waste. Plasma Physics and Controlled Fusion.

[3] Chernets OV, Korzhyk VM, Marynsky GS, Petrov SV, Zhovtyansky VA. Electric arc steam plasma conversion of medicine waste and carbon containing materials. In: Jones JE, editor. Proceedings of XVII GD; 7–12 September, 2008; Cardiff, Wales: Cardiff University;

[4] Hrabovsky M, Hlina M, Konrad M, Kopecky V, Kavka T, Chumak O, Maslani A. Thermal plasma gasification of biomass for fuel gas production. Journal of High Temperature

[5] Ducharne C. Technical and economic analysis of Plasma-assisted Waste-to-Energy pro-

[6] Brattsev AN, Kuznetsov VA, Popov VE, Ufimtsev AA. Arc gasification of biomass:

[7] Byun Y, Cho M, Hwang S-M, Chung J. Thermal plasma gasification of municipal solid waste (MSW). In: Yun Y, editor. Gasification for Practical Applications. Rijeka, Croatia:

[8] Zhang Q, Dor L, Fenigshtein D, Yang W, Blasiak W. Gasification of municipal solid waste

[9] Zhovtyansky VА, Petrov SV, Lelyukh YI, Nevzglyad IО, Goncharuk YA. Efficiency of renewable organic raw materials conversion using plasma technology. IEEE Transactions

[10] Fabry F, Rehmet C, Rohani V-J, Fulcheri L. Waste gasification by thermal plasma: A review. Waste and Biomass Valorization. 2013;4(3):421-439. DOI: 10.1007/s12649-013-9201-7

in the plasma gasification melting process. Applied Energy. 2012;90:106-112

cesses. Earth Engineering Centre, Columbia University. 2010. p. 50

Example of wood residue. High Temperature. 2011;49:244-248

Thus, the proposed plasma-steam-oxygen technology of waste treatment has the highest calculated efficiency indicators compared with the developments under discussion. At the same time, it provides high levels of environmental safety. Further to improve the efficiency of this technology, it can facilitate the transition to more efficient methods of electricity production from syngas obtained [13]. This will lead to increasing value ηЕЕ and, respectively, further decrease of the part of synthesis gas that is used for energy self-sufficiency of gasification equipment. Such prospects are associated primarily with fuel cell technology that has significantly greater efficiency than gas-diesel power stations.
