Category: Posts

Introduction

The complex topic of sustainability has many facets within it.

Being sustainable means not only using the right energy resources, but also making the most of them by increasing one’s efficiency. This implies making maximum use of the energy source at one’s disposal to reap the maximum benefit.

Renewable energy technologies today have made great strides and are increasingly important in reducing the environmental footprint. Such resources, however, are often characterized by low efficiency. Just think, for example, of photovoltaic systems whose efficiency is estimated to be around 15-20%.

To overcome the problem of thermal waste and increase the efficiency of one’s business, it is necessary to implement special technologies capable of recovering energy that would otherwise be dissipated: ORC systems.

This technology, which also makes the most of low-temperature heat flows, makes use of a special turbine that provides not only improved efficiency. In fact, some of its main advantages are also reducing its environmental footprint by reducing the release of CO2 into the atmosphere, and producing electricity.

Technology

• A heat source [1] heats a carrier fluid (water or, in larger systems, thermal oil) circulating in a closed circuit. The carrier fluid conveys the absorbed heat to one or more primary heat exchangers, usually a preheater and an evaporator [2], where the heat is transferred from the carrier fluid to the working fluid.
• The fully biodegradable and environmentally friendly organic fluid is put under pressure by a pump [7] and sent to the exchanger-evaporator, where it is transformed, as it expands, from a liquid into a vapor.
• The organic fluid in the form of vapor, expanding, drives the Turbine[3] to whose shaft the rotor of an alternator is attached. The high-speed rotation (12,000÷18,000 Rpm) of the turbine will, once driven, generate electricity.
• The working fluid, still in the gaseous phase, is conveyed inside the condenser [5], where it is cooled by releasing its excess heat. Collected within a condenser tank, the working fluid is thus ready to be fed back into the system through a recycle pump, thus closing the cycle.
• The excess heat released into the condenser itself represents a source of low-temperature thermal energy that can be used for other purposes such as preheating or drying fuel biomass to increase its heating value, heating buildings, producing hot water, and so on. In case there is no way to employ it, the waste heat can be dissipated through an external cooling system (dry cooler) [6].

Application

The Organic Rankine Cycle, operating at low temperatures, lends itself excellently to the realization of heat recovery systems.

The sectors in which this technology finds application, providing different benefits, are diverse:

• Heat Recovery from Industrial Processes: ORC systems can recover waste heat from various industries such as paper, cement, glass, ceramics, and steel. Operating at low temperatures, the Organic Rankine Cycle, lends itself excellently to thermal recovery, , enhancing hitherto unnecessarily wasted thermal waste.
• Geothermal: Geothermal energy is a form of renewable energy derived from the earth’s internal heat. By inserting a thermal collection system into an existing hot spring or by injecting cold water into an ad hoc borehole drilled at appropriate locations on the earth’s surface, a flow of water with a high enough flow rate and temperature to drive one or more ORC systems can be obtained.
• Solar Thermodynamic: ORC systems lend themselves easily to the realization of solar thermodynamic or hybrid systems, due in part to their excellent performance under partial load-that is, when the thermal energy is below nominal specification values. Such systems are able to harness the relatively low temperature heat obtained from simple concentrating solar thermal panels as long as it is available. Hybrid systems can then switch automatically to the exploitation of alternative thermal sources (biomass or biogas boilers, geothermal heat….) if solar production is insufficient, such as at night or in inclement weather.
• Recovery from Engines: ORC modules, enhancing the low temperatures at which they operate, are an excellent choice for heat recovery from the most varied types of engines and generators (gensets) to which they can be safely and effectively interfaced through a simple closed circuit with hot or superheated water that guarantees efficiency, safety and plant engineering simplicity.

Advantages

Thermal recovery systems through ORC cycle, due to their technology provide a number of advantages:

• They enhance low-temperature thermal flows that would otherwise be lost
• They are applicable to different thermal sources (superheated acuqa, flue gas, etc.)
• They increase the efficiency of the systems in which they are installed
• They reduce the level of CO2 released into the atmosphere
• Reduce energy costs by producing electricity

Crediamo che l’efficienza sia il cuore di un economia sostenibile!

In un momento storico come quello odierno in cui è fondamentale sfruttare le risorse rinnovabili, i sistemi Organic Rankine Cycle rappresentano una risorsa cruciale per la riduzione delle emissioni di CO2 e la diminuzione dei costi.

​In questo articolo di La Repubblica, Alessandro Zuccato, spiega il funzionamento e i benefici che i sistemi ORC made in Verona possono apportare ai diversi settori in cui è possibile impiegarli. In ottica di un economia circolare e pulita questa tecnologia, utilizzando una risorsa di scarto, permetterà ottenere energia elettrica ​ a bassissimo costo.

 

Oil & Gas

The ORC systems of Zuccato Energia allow the production of electricity up to 500 kW by recovering the waste heat from the Oil & Gas plants.

 

Applications:

It is possible to recover heat from each hot source present on the site: the hot water from the oil extraction, the fumes deriving from flaring, the thermal waste from the refineries, and the engines located in the natural gas liquefaction station and the gas station pumping.

 

ORC system operation

The ORC system through an exchanger (evaporator), recovers the heat from these hot sources and heats a non-toxic organic fluid. This fluid, in vapor form, is expanded in the turbine. This fluid expansion spins an impeller inside the turbine, generating mechanical energy which is converted into electricity by a direct-drive turbo-generator. The electricity produced in this way is used on-site or fed into the network. At the turbine outlet, the working fluid enters into a second heat exchanger (condenser), where it transfers its excess heat and condenses back to being a liquid. The working fluid in the liquid phase is then sent back to the exchanger-evaporator by a special pump, thus completing the closed circuit.

 

Fumes deriving from flare gas

Wasted gases are inevitably produced during the oil extraction operations. These gases must be burned using either appropriate torches or incinerators. ORC technology is ideal for converting those wasted gases into electricity. In this case, the ORC is positioned downstream of the gas combustion system and with the addition of a heat exchanger, it produces usable electricity in the entire system.

Case study – Flaring

ZE ORC System – Oil & Gas (Mexico)

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Heat recovery from engines’ thermal waste

 

The heat sources available in engines are two: exhaust gas and cooling jackets.

• Exhaust gases: high temperature
• Cooling jackets: low temperature

 

It is possible recover the exhaust gas with a heat exchanger while the cooling jackets can be directly exploit in the form of water.

 

FUNCTIONAL SCHEME

ADVANTAGES

Exploit both the thermal sources
Thanks to the arrangement of the machine components, it is possible to recover heat from both sources. In this way we have greater efficiency with a greater result in terms of electricity.

It lowers the consumption of the engine’s Dry Cooler
By placing an exchanger downstream of the engine dry cooler, the water that must return to the cooling jackets is first cooled by our heat exchanger. In this way, the dry cooler of the motor requires less power of action.

Better payback by installing only one machine
By installing just one machine, you have a better return on investment than buying two units. There are also advantages in terms of maintenance and component purchase costs.

 

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How recover the thermal energy from engines

 

CARILEC (Caribbean Electric Utility Services Corporation) allowed us to explain how our ORC modules are efficient for recovering the waste heat produced by the diesel and biogas engines.
This solution can offer clean electricity and the achievement of the environmental sustainability core business.

 

 

ORC plant start-up for industrial process

 

We are pleased to announce the start-up of our ORC system for an glass industrial process.

The Vetreria di Borgonovo glasswork in Piacenza, Italy. The factory, which covers 52.000m², produces about 45.000 tonnes of glass per year using two modern melting furnaces.

The system realized involves the operation of an ZE-200-LT ORC module produces up to 200 kW of electricity, recovering 1400 kWt from the furnace’s fumes. The module recovers the waste heat and through a closed process produces clean electricity to use in the overall plant. The recovery is carried out employing a heat exchanger which intercepts the flue gases from the furnaces and uses them to heat some water, the vector fluid necessary for the operation of the ORC system.

The electricity production is zero emissions: the glasswork can avoid 274 TOE and 376 tonnes of CO₂ per year.

ORC Plant – Vetreria di Borgonovo Spa

Container top view – Vetreria di Borgonovo Spa

Waste heat recovery through ORC technology becomes the means to achieve the goal of “environmental sustainability”: recovering heat at medium and low temperatures indeed, allows to reduce the environmental impact of industrial processes and at the same time to reduce their economic impact allowing them to exploit their waste and to convert them into electricity, with high flexibility, minimal maintenance requirements and with custom made components.

 

 

 

 

ORC system produces electricity from heat recovery in the treatment and disposal of waste.

 

Energy recovery takes place from the recovery of the exhaust fumes of incinerators or engines powered by the biogas produced by the waste itself.

One of our ORC systems has found application in a waste management plant and uses the waste gases of the incinerator.

An incinerator is a waste disposal facility that works by destroying inert materials. In practice, the waste is burned or, as the word itself suggests, “incinerated”. The fumes deriving from combustion must be adequately monitored and filtered and can be used precisely in the Organic Rankine Cycle.

The heat recovered from the incineration processes is converted and used to generate electricity.

Our ZE-200-LT ORC system is applied by recovering 2000 kW of thermal power. In this way, the waste treatment plant manages to dispose of its waste and at the same time produce clean electricity without CO2 emissions into the atmosphere.

 

 

COMPARISON OF FOUR TYPES OF RADIAL TURBINES FOR A 250KW ORC POWER INSTALLATION

 

Maksim Smirnov, Natalia Kuklina, Aleksandr Sebelev, Alessandro Zuccato and Nikolay Zabelin

Peter the Great St. Petersburg Polytechnic University (SPbPU), St. Petersburg, Russia

Zuccato Energia Srl, via della Consortia 2, Verona, Italy

*Corresponding Author: m.smirnov.turbo@gmail.com

 

 

ABSTRACT

 

This paper seeks to compare four solutions for an ORC power plant rated at 250 kW running with R1233zdE as the working fluid: a radial inflow – axial outflow turbine with a typical reaction about of 0.5, a radial centripetal turbines with reaction of 0.36 and 0.05 and an impulse centrifugal turbine. All these turbines are single stage and high-speed. Steady state CFD simulations were carried out to assess the performance at the design and partial load as well as the axial force values.

As expected, the radial inflow turbine has exhibited the best performance, followed then by the centripetal reaction turbine with 4% of a relative efficiency decrease. Both impulse turbines have shown 11% less efficiency at the design point comparing to the radial inflow stage. Under the partial load, the turbines have exhibited different trends of their efficiency behaviour.

In particular, with a power output reduction from 100 to 40%, the radial inflow and the centripetal turbine have lost 7% of their efficiency, while the centripetal impulse turbine 20% and the centrifugal impulse just 5%.
The axial force of the radial inflow and both centripetal stages may be balanced to reach a desired value by means of the modification of the disk back seal. Instead, the centrifugal impulse stage fails to provide such a balancing, which results in high values of the axial thrust even despite an impulse nature of this stage.

 

 

ORC System – Heat recovery

 

Alessandro Zuccato, CEO of Zuccato Energia, explains to Glass International how ORC (Organic Rankine Cycle) technology is particularly effective for recovering the dispersion of waste heat produced by glass production. This technology helps glassmakers to produce clean electricity with consequent economic savings and achieve a vision focused on environmental sustainability.

 

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The ceramics sector is classified among the energy-intensive, being the fourth industrial sector for energy consumption. In fact, 1.67 MWh of energy is required to produce just one ton of ceramic tiles.

Thanks to our projects, the ceramic industry can see an ecological change in its production through the recovery of residual heat. It is possible to intervene on several levels, by positioning an exchanger in the fumes line upstream of the bag filter or in the hottest part of the cooling stages of the oven.

From an oven with an available thermal power of 1239 kWt, it is possible to put our 175 kWe ORC module into operation.

Here is the case study with the business plan.

 

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