Design of an Energy-Efficient Pilot-Scale Pyrolysis Reactor Using Low-Cost Insulating Materials

Abstract

A pilot-scale reactor prototype was designed to produce hydrocarbons through the catalytic pyrolysis process of low-density polyethylene, thereby extending its life cycle and contributing to energy efficiency and sustainability. The reactor consists of a stainless-steel tank encased in a ceramic jacket with refractory cement and clay bricks. The tank, made of 304 stainless steel, ensures mechanical strength and efficient heat transfer to the reactor core. A spiral condenser was incorporated into a water tank to cool the vapors and recover the liquid oil. The insulating materials, ceramic, refractory cement and clay brick, demonstrated a high combined thermal resistance of 0.159 m²·K/W. Simulations and energy flow calculations demonstrated that heat is efficiently directed to the reactor core, reaching 350 °C with only 3000–3800 W, while the outside of the jacket remained close to 32 °C. These results confirm that the proposed design improves thermal efficiency and optimizes energy use for catalytic pyrolysis. The novelty of this design lies in its energy-efficient configuration, which can be replicated in rural regions worldwide due to the accessibility of its construction materials. This reactor was developed based on a smaller-scale model that previously yielded excellent results.

1. Introduction

Energy is fundamental for human needs, economic growth, and social well-being. However, global energy demand is projected to increase by nearly 50% between 2018 and 2050 [1], while around 80% of primary energy still comes from fossil fuels, which generate large amounts of CO₂ emissions [2,3]. To address this challenge, research has focused on two main strategies: expanding renewable energy sources and improving efficiency through integrated systems that optimize energy use [4]. These approaches not only reduce emissions throughout the life cycle of energy systems but also align with regulatory policies on consumption and demand [5]. Achieving sustainable development requires a transition toward low-carbon models that foster economic growth, reduce inequalities, and protect the environment [6]. In this context, renewable sources such as solar, wind, and biomass play a key role [7,8].

Among emerging renewable technologies, catalytic pyrolysis of plastic waste offers a promising pathway to simultaneously address energy generation, emission reduction, and circular economy goals [9,10,11,12,13,14,15,16,17,18]. Plastic production has facilitated global packaging and transportation, yet poor recycling practices have turned plastics into one of the most pressing environmental threats, with global demand increasing by about 5% annually [17]. Currently, only around 10% of plastic waste is recycled, while the rest accumulates in landfills, rivers, and oceans, releasing toxic gases during incineration [19]. These challenges highlight the urgent need for innovative and sustainable recycling technologies that can contribute to the goals of the 2030 Agenda.

Pyrolysis represents a viable thermochemical route for converting plastic waste into valuable fuels while avoiding the toxic emissions associated with incineration [20,21,22]. In particular, catalytic pyrolysis using zeolite-based catalysts improves oil yield and quality at lower operating temperatures, producing high-energy bio-oil and gas [23,24,25,26,27]. Previous studies have reported yields up to 22.5% using catalysts, compared to 18% for thermal pyrolysis [28,29,30,31,32,33,34]. The process produces liquid hydrocarbon oil, non-condensable gas, and a solid residue. In previous work performed by our group, a laboratory-scale prototype demonstrated that this liquid fraction is composed of gasoline-like aromatic hydrocarbons, including benzene, toluene, and xylenes [35].

Scaling up this technology requires efficient reactor designs that ensure safety, thermal stability, and economic viability. Parameters such as heat transfer efficiency, condenser performance, and multilayer insulation play crucial roles in maximizing energy recovery and process sustainability [29,33,36]. While most existing designs remain at laboratory or small pilot scale, developing cost-effective semi-industrial reactors from locally available materials offers a practical solution, especially for rural contexts [35]. Such innovations support environmental sustainability and energy access objectives [36,37,38].

Various reactor configurations have been reported for plastic pyrolysis, including batch, semi-batch, fixed-bed, fluidized-bed, rotary kiln, and flow reactors. Batch and fixed-bed systems are simple and suitable for laboratory studies but often suffer from uneven heating and limited scalability. Fluidized-bed reactors provide uniform temperature distribution and continuous operation but require complex control systems and high construction costs. Rotary kilns can process larger feedstocks but entail higher energy consumption and mechanical complexity. Flow reactors, while efficient for gaseous or liquid feeds, are less adaptable for solid plastics [39,40,41].

Regarding construction materials, most reactors are built using stainless steel (grades 304 or 316) due to their high-temperature resistance, corrosion protection, and mechanical strength [13,14,15]. Some designs incorporate carbon steel or nickel-based alloys to reduce cost, while refractory linings and ceramics are applied to minimize heat losses [16]. However, these industrial materials increase fabrication cost and limit accessibility for decentralized applications.

The present work addresses these challenges by proposing a pilot-scale reactor constructed from low-cost and locally available materials, including refractory cement, ceramic, and red clay brick for insulation, combined with a stainless-steel core for mechanical stability. This configuration balances energy efficiency, durability, and affordability, making it suitable for implementation in rural or low-resource regions [18,19,42].

Overall, this study helps bridge the gap between laboratory-scale systems and real-world applications, demonstrating that high thermal efficiency can be achieved through simple, replicable, and affordable reactor designs. The proposed reactor emphasizes heat retention through multilayer insulation, reduced energy consumption, and scalability for decentralized contexts. Unlike complex microwave-assisted or continuous-flow systems, this design highlights simplicity, energy efficiency, and adaptability. Its innovation lies in demonstrating that high energy performance can be achieved using low-cost, locally available materials, enabling decentralized implementation of catalytic pyrolysis in regions lacking industrial infrastructure.

2. Results

2.1. Prototype Description

The prototype comprises a reactor consisting of a steel tank encased in two layers of high-temperature ceramic and refractory cement, forming the external insulation (see Figure 1). The reactor lid is connected via tubing to a condenser, which consists of a water reservoir and a coiled tube and is further linked to a liquid–gas separator.

This study focuses on the thermal efficiency and mechanical design of the reactor’s insulated vessel. For clarity in the thermal model, essential components such as the feed system and external heat source have been considered but are not detailed in the figures. The design allows loading through a sealed flange on the lid and is intended to be heated by an integrated combustion chamber located below the vessel. This chamber is specifically designed to be fueled by high-calorific briquettes developed from local biomass waste, in line with the project’s goal of creating a low-cost and sustainable system.

During operation, plastic waste is introduced into the steel tank of the reactor. Upon heating, thermal energy is transferred to the plastic, inducing its thermochemical decomposition and phase transition from solid to liquid and gaseous products. The resulting vapors are conveyed through the tubing to the condenser, where the coil, immersed in water, promotes cooling and condensation. This process converts the gases into liquid hydrocarbons, known as pyrolysis oil.

2.2. Thermal Properties of Materials

Finding suitable alternative resources is essential to reduce traditional energy consumption and promote sustainable development. Energy efficiency is a key sustainability goal, and thermal insulation materials have been developed to meet this objective by combining low thermal conductivity, low density, and high thermal resistance [43]. Energy saving is a strategic objective that contributes to environmental protection and the preservation of natural resources. Thermal insulation is therefore an increasingly important tool for conserving energy.

Table 1. Thermal conductivity of materials used for the reactor jacket design.

Material	Thermal Conductivity $\mathbf{W}/\mathbf{m}·\mathbf{K}$	Thickness m
Ceramics	1.4	0.025
Refractory Cement	1.2	0.01
Red clay brick	0.9	0.12
Steel 304-2B	16.2	0.0016

and

Table 2. Thermal resistance of materials.

Material	Value of R (m2·K/W)
Ceramics	0.018
Refractory cement	0.0083
Red clay brick	0.133
Stainless steel 304-2B	0.000098

present the thermal properties of traditional insulation materials as reported under standardized testing [44].

To analyze energy efficiency in the reactor design, two key aspects were considered: thermal conductivity and thermal resistance. These properties were used to design the reactor jacket to minimize heat loss by conduction and convection.

Thermal resistance is defined as the ratio of the temperature difference between the two faces of a material to the rate of heat flow per unit area. Thermal resistance determines the heat insulation property of a material [45]. The higher the thermal resistance, the lower is the heat loss. The thermal resistance, R $(\mathrm{m}$²$·\mathrm{K}/\mathrm{W}$), is connected with the thermal conductivity, λ ($\mathrm{W}/\mathrm{m}·\mathrm{K}$), and the thickness, τ (m), as follows:

$$R={\displaystyle \frac{\tau }{\lambda }}$$

(1)

for example, the ceramic layer has

$$R=0.025 \left(\mathrm{m}\right)/1.4 (\mathrm{W}/\mathrm{m}·\mathrm{K})\approx 0.018 {\mathrm{m}}^2·\mathrm{K}/\mathrm{W}$$

As expected, the red clay brick, exhibits the highest R value, followed by the ceramics and refractory cement, while steel shows the lowest. The combined thermal resistance of the insulating layers is 0.1593 m²·K/W, which is over 1625 times higher than that of the steel layer alone (0.000098 m²·K/W). This confirms that the insulation layers substantially enhance heat retention and energy efficiency in the reactor design.

2.3. Heat Transfer and Thermal Efficiency

Convective heat transfer is one of the three fundamental mechanisms of heat exchange between a solid surface and a surrounding fluid, such as air. It is described by Newton’s law of cooling, which relates the heat transfer rate to the surface area, the convective heat transfer coefficient, and the temperature difference between the surface and the fluid. The heat transfer in the reactor wall was analyzed considering convection and conduction layers, following Newton’s cooling law [46,47]. In the context of the jacketed reactor, convective heat flow plays a critical role in determining how heat is dissipated from the reactor surface to the surrounding environment. Accurate estimation of this heat transfer rate is essential to assess the thermal efficiency of the reactor, guide the design of the insulation system, and ensure that the desired internal temperatures are achieved while minimizing energy losses. At a steady state and under perfectly mixing conditions, the heat transfer rate can be evaluated as [48]

$$Q_H=h_T{A}_H(T_s-T_b)$$

(2)

where $h_T,A_H,T_s,\mathrm{a}\mathrm{n}\mathrm{d}{T}_b$ are the heat transfer coefficient, $Q_H$ is the heat transfer rate (W), $h_T$ is the heat transfer coefficient ($\mathrm{W}/{\mathrm{m}}^2·\mathrm{K}$) with a value for air of $h_T=15\mathrm{W}/{\mathrm{m}}^2\mathrm{K}$; $A_H$ is heat-transfer area (${\mathrm{m}}^2$), $A_H$= $0.78{\mathrm{m}}^2$; $T_s$ is the surface temperature of the heating (°C), $T_s$ = $350°\mathrm{C}$ and $T_b$ is the fluid temperature, $T_b$ = 25 °C. Thus, $Q_H\approx 3802\mathrm{W}$.

This calculation provides an estimate of the power needed to reach 350 °C, which was taken as the base parameter in the simulation.

The simulation results indicate that thermal energy is concentrated toward the center of the tank, while the multilayer insulation effectively minimizes heat loss to the surroundings. As shown in Figure 2, the internal temperature of the tank reaches 350 °C, whereas the external jacket surface remains below 32 °C, confirming the efficiency of the insulation system.

The convection coefficient ($h_T$) depends on factors such as temperature, wind speed, and surface orientation. For upward and horizontal heat flow, $h_T$ can reach ~9.26 W/m²·K for absorbent surfaces and ~4.31 W/m²·K for reflective ones. Under outdoor natural convection, typically ranges between 5 and 25 W/m²·K. Conversely, experimental studies report that for downward-facing surfaces $h_T$ ranges between 0.4 and 2.05 W/m²·K, while in closed spaces it is generally lower due to restricted air circulation [35,49].

Table 3. Results of applied energy and temperature under different convection scenarios.

Radiation Steel Emissivity	Heat Flux W/m2	Convection W/m2·K	Heat Power W	Temperature Max. °C	Temperature Min. °C	Surface Temperature °C
0.3	656.4	25	3000	268	49	151
0.3	1094.0	25	5000	411	66	238
0.3	2188.0	25	10,000	697	106	401
0.3	4376.0	25	20,000	1000	215	659
0.3	656.45	10	3000	507	161	265
0.3	1094.09	10	5000	645	199	310
0.3	1531.17	10	7000	757	234	364
0.3	1750.54	10	8000	806	251	375
0.3	2188.18	10	10,000	895	285	420
0.3	656.45	7	3000	551	214	340
0.3	875.27	7	4000	622	234	345
0.3	1094.09	7	5000	685	255	360
0.3	1312.91	7	6000	742	276	380
0.3	1750.54	7	8000	841	316	450
0.3	218.0	2	1000	467	322	400
0.3	328.0	2	1500	513	339	444
0.3	437.0	2	2000	556	355	456
0.3	656.0	2	3000	631	387	533
0.3	1094.0	2	5000	755	419	587

summarizes the applied conditions and the calculated values for the maximum and minimum internal temperatures of the tank, as well as its surface temperature.

During the pyrolysis process, the working pressure inside the tank is assumed to be approximately 1 bar. However, the prototype has been designed to withstand higher pressures of several bars. To ensure safe operation, a pressure gauge has been installed for continuous monitoring, and a relief valve has been incorporated to mitigate the risk of overpressure due to potential blockages in the outlet pipe. The simulation model was conceptually validated against our previous experimental work on a smaller-scale prototype. That published study demonstrated the feasibility of the thermal concept and the effectiveness of the operating parameters. Therefore, the present study uses those parameters as a reference to model the scalability and thermal performance of the pilot-scale design, which is a critical step prior to construction.

3. Discussion

The steady-state simulations highlight the decisive role of convection in determining the energy demand to achieve pyrolysis conditions. Under adiabatic conditions, where all applied energy is retained by the reactor, variations in the convection coefficient strongly influence the heating power required to reach 350 °C. In free-air conditions (25 W/m²·K), pyrolysis was only achieved at 10,000 W, evidencing extensive heat loss due to natural convection. When the convection coefficient was reduced to 10 W/m²·K, the required power decreased to 7000 W, while a further reduction to 7 W/m²·K lowered the demand to 5000 W. The most pronounced effect was observed at 2 W/m²·K, which approximates a near-adiabatic condition in the insulated reactor jacket, where pyrolysis was reached with only 1000 W. These results confirm that multilayer insulation effectively minimizes heat loss by reducing direct contact with ambient air.

Overall, the findings underscore the decisive role of convection control in pyrolysis reactor design. Open-air configurations demand much higher energy input, whereas insulation and reduced air movement drastically reduce the required heating power, enhancing both energy efficiency and process sustainability. Although all four scenarios surpassed the pyrolysis threshold, the energy demand varied by an order of magnitude, from 10,000 W in open-air conditions to just 1000 W under near-adiabatic conditions. Minimizing convective heat transfer is therefore essential to achieve substantial energy savings in thermal processes.

The proposed prototype design directly addresses these challenges. The insulating jacket was conceived to minimize heat losses by limiting direct contact with ambient air, while the selected materials are suitable for high-temperature operation. Refractory ceramic, with thermal conductivity between 1.4 and $3.0\mathrm{W}/\mathrm{m}·\mathrm{K}$, withstands 1650–2500 °C, while refractory cement, with conductivity values ranging from 1.2 to $4.0 \mathrm{W}/\mathrm{m}·\mathrm{K}$, operates up to 2200 °C. Red brick, composed primarily of clay, provides additional thermal resistance. For the reactor tank, 304 2B stainless steel was selected due to its favorable thermal conductivity ($16.2\mathrm{W}/\mathrm{m}·\mathrm{K}$), which promotes efficient heat transfer toward the reactor core and supports efficient pyrolysis. Figure 3, summarizes the influence of convection on reactor performance and highlights how insulation strategies translate into lower energy demand.

These results not only demonstrate the thermal efficiency of the proposed design but also provide a scalable framework for energy optimization in larger systems. The same insulation principles can be applied to semi-industrial pyrolysis units to reduce operational costs and energy consumption. The proposed design methodology is based on accepted principles, including ASME Section VIII codes for pressure vessels and standard heat transfer equations. Thus, although the specific values of the calculations correspond to an 800-L pilot reactor, the methodology used can be adapted to the design of larger-scale reactors by simply adjusting the input parameters (dimensions, materials, and operating conditions).

4. Materials and Methods

4.1. Reactor Tank Material

For reactor design, stainless steel is a good choice due to its mechanical, thermal, and oxidation-resistance characteristics. Stainless Steel 304-2B is an austenitic stainless-steel alloy with a surface finish known as 2B, which refers to a cold-rolled surface that is then treated with a passivation treatment. Stainless steel 304 is widely used due to its good corrosion resistance and its versatility in various industrial applications [49].

The allowable stress or resistance limit of 304-2B stainless steel may vary depending on the norm or standard used, as well as the specific load and temperature conditions. Thus, it is important to consult the applicable technical specifications or standards for accurate allowable stress data. For reference, the typical yield stress of 304 stainless steel is in the range of 205 to 275 MPa. This stress must be taken into account in the design due to the pressures to which the material will be subjected, and the tensile strength, which is generally between 515 and 690 MPa. These values may vary depending on the condition of the material and the heat treatments applied [45,50]. The thermal conductivity of 304-2B stainless steel is $16.2\mathrm{W}/\mathrm{m}·\mathrm{K},$ which is relevant for heat transfer in the pyrolysis reactor and its simulation.

Three thicknesses and their compositions are considered: 1.5, 2.0 and 3.0 mm as shown in

Table 4. Chemical composition of base metal (% by weight) [51].

Thickness (mm)	C	Mn	Si	Cr	Ni	Mo
1.5	0.09	1.04	0.44	17.75	7.69	0.13
2.0	0.05	0.99	0.56	17.60	8.00	0.14
3.0	0.09	1.02	0.40	17.97	8.06	0.20

.

4.2. Reactor Tank Design

The design of vessels operating under internal pressure is based on NRF-028-PEMEX-2004 [16], Chapter 8, paragraph 8.1.2, which refers to the UG part of Section VIII, Division 1. This part of the ASME Code [15], provides formulas and parameters that must be considered for the design. These variables are mainly pressure $\left(P\right)$ and design temperature (T). For circumferential stresses, as taken from ASME Section VIII, Division 1, construction of internal pressure vessels, the following expression is used [52,53]:

$$P={\displaystyle \frac{SE\tau }{r+0.6\tau }}$$

(3)

$$\tau ={\displaystyle \frac{PR}{SE-0.6P}}$$

(4)

where τ is the minimum wall thickness (mm), $P$ is the design pressure Psi (MPa), $r$ is the internal radius in $\left(\mathrm{m}\mathrm{m}\right)$, $S$ is the maximum stress of the material at the desired temperature Psi (MPa), $E$ is the material joint efficiency.

For an 800-L tank made of 14-gauge 304-2B stainless steel plate $1.92 \mathrm{mm}$ thick, the following values were used: $\tau =1.92\mathrm{m}\mathrm{m}$, $r=500\mathrm{m}\mathrm{m}$, $S=250\mathrm{M}\mathrm{P}\mathrm{a}$ stainless steel stress, E is 1 (ASME Section VIII division 1).

The design pressure was calculated as: P $={\displaystyle \frac{\left(250\mathrm{M}\mathrm{P}\mathrm{a}\right)\left(1\right)\left(1.92\mathrm{m}\mathrm{m}\right)}{500\mathrm{m}\mathrm{m}+0.6\left(1.92\mathrm{m}\mathrm{m}\right)}}$.

The calculations indicate that $P$ has a value of $0.958\mathrm{MPa}$. Considering a 50% safety factor, the working pressure is P ≈ 0.48 MPa. Figure 4 shows the tank design with the characteristics specified above.

The volume of the tank is $800\mathrm{L}$ ($0.8{\mathrm{m}}^3),$ and the density of LDPE is $920\mathrm{k}\mathrm{g}/{\mathrm{m}}^3$. The density of LDPE (0.92 g/cm³) was taken from ASTM D792-13 [54]. The maximum mass of plastic the tank can hold is calculated as

m = v p

(5)

where m is the mass (kg), v is the volume (${\mathrm{m}}^3$), p is the density ($\mathrm{k}\mathrm{g}/{\mathrm{m}}^3$).

Thus, m = ($0.8{\mathrm{m}}^3$)($920\mathrm{k}\mathrm{g}/{\mathrm{m}}^3$) = $736\mathrm{k}\mathrm{g}.$

The feed load in batch pyrolysis reactors is commonly expressed as a fill ratio (per-centage of reactor volume occupied by feedstock). This has a significant impact on heat transfer, particularly in indirect heating designs such as the one proposed. Batch configurations can suffer from poor heat transfer characteristics when processing low-conductivity materials such as plastics. To ensure more uniform heating, a low fill ratio is preferable. Therefore, an operating fill ratio range of 10% to 15% has been selected for this 800 L pilot reactor. This corresponds to a workload between 73.6 kg (at 10%) and 110.4 kg (at 15%) of LDPE per batch [55,56].

Figure 5 shows a cross-section of the tank and its interior volume view for containing plastic during the catalytic pyrolysis process.

The design of the cover is flat to adapt to the tank flange, aiming to achieve a total seal and prevent gas escape. The connection pipe to the condenser and the pump was also included to allow vacuum creation, and the cover is also made of stainless steel, as shown in Figure 6.

A flanged joint will be placed on both the flat cover and the tank. Its design follows the ASME Section VIII code:

$$\tau =D\sqrt{{\displaystyle \frac{c\ast p}{S\ast E}}}$$

(6)

where τ is the minimum flange thickness (mm), p is the design pressure (0.48 MPa), D is the flange diameter (550 mm), S is the maximum stress of the material (250 MPa), E is the material joint efficiency (1), and c is the factor for the type of cover joint (bolted plates: 0.162).

The minimum flange thickness for the cover and tank is t = 10 mm + 10% safety = 11 mm. The flange, designed to fit the tank opening, is shown in Figure 7.

To calculate the force on each screw, the cover area (1963 cm²) is multiplied by the working pressure obtained from Equation (1). This gives a total force of $94 \mathrm{k}\mathrm{N}.$ Since the design uses eight screws, the load per screw is $11.75 \mathrm{k}\mathrm{N}.$ Such a load can be safely supported by a half-inch diameter screw or its metric equivalent [57].

4.3. Reactor Jacket

The objective of the jacket design is to improve energy efficiency by minimizing heat loss through convection and concentrating it within the reactor tank. The proposal follows an ecological approach by reducing energy consumption and involves the construction of a jacket that covers the tank with three thermally insulating layers, selected based on their material characteristics. The first layer is a high-alumina, hydraulic-setting castable refractory cement, suitable for applications exceeding 1000 °C. The second layer consists of a high-purity alumina-silica ceramic fiber blanket, a lightweight insulating material with a service temperature rating of up to 1200 °C. The third layer is made of red clay brick wall, as shown in Figure 8. The materials chosen provide a significant safety margin against possible temperature overshoots and ensure the long-term structural durability of the jacket over many operating cycles.

4.4. Simulation Parameters

A thermal simulation of the prototype was performed in SolidWorks 2011 SP05 [58] using the following parameters: the reactor tank, constructed of 14-gauge 304 stainless steel with a thermal conductivity of $16.2 \mathrm{W}/\mathrm{m}·\mathrm{K}.$ The jacket surrounding the tank consists of three layers: (i) refractory cement ($1.2 \mathrm{W}/\mathrm{m}·\mathrm{K}$), (ii) ceramic insulation ($1.4 \mathrm{W}/\mathrm{m}·\mathrm{K})$, and (iii) red clay brick ($0.9 \mathrm{W}/\mathrm{m}·\mathrm{K}$).

A heating power input of 3000 W was applied. Furthermore, a parametric analysis was conducted by varying the heating power and setting different convection coefficients (25, 10, 7, and 2 W/m²·K) to assess the reactor’s performance under different operational conditions. A constant emissivity of 0.3 was used for the external surfaces. The analysis focused exclusively on heat transfer, assuming external atmospheric pressure conditions, and did not evaluate the mechanical stress related to the reactor’s internal design pressure of 0.48 MPa.

5. Conclusions

This study presents the design and simulation of a pilot-scale catalytic pyrolysis reactor for the recycling of low-density polyethylene (LDPE). The reactor achieved an internal temperature of 350 °C using only 3000–3800 W, while the external surface temperature remained below 32 °C, confirming the high thermal efficiency of the multilayer insulation system. The combined thermal resistance of the multilayer insulation system was 0.1593 m²·K/W, over 1600 times higher than that of the stainless-steel wall alone, significantly reducing heat losses.

The simulations showed that reducing the convection coefficient from 25 W/m²·K (open air) to 2 W/m²·K (insulated condition) decreased the power demand from 10,000 W to only 1000 W, representing an order of magnitude improvement in energy efficiency. These results validate the concept of using low-cost, readily available materials such as ceramic, refractory cement, and clay bricks to achieve high performance.

The novelty of this design lies in its simplicity, replicability, and accessibility: it can be built and installed in rural or low-resource areas without the need for complex equipment. The prototype was scaled up from a smaller reactor that previously demonstrated excellent experimental results, confirming the feasibility of the approach.

Future work will include experimental validation of the pilot reactor and quantitative comparison between simulated and measured data. Furthermore, a detailed optimization study will be carried out to analyze the cost–benefit ratio of the insulation layer thicknesses, refining the thermal model and confirming its scalability.