SULFAD system and catalyser

First of all we offer a tailor made, turnkey project where we give the hardware producer.

  • Feasibility study for 120.000 € which payment after to order the project will reduce from the total price.

1 Purpose
2 scope of supply for the study
2.L Technical base data of the pre-engineering
2,Z Scope of engineering and Coordination
2.3 List of deliverables
3 Time schedule
4 confidentiality
5 Drawings. descriptions and IP-rights
6 Price
7 payment schedule
8 payment conditions
9 Other Terms
10 Exclusions & exceptions
10.1 Other issues
+ Business plan

What is the benefit to using the SULFAD?



Ms Szabina Sebestyen            Jenő Marton
Marketing and Business         Development Manager Director

On behalf of Solar Research and Development Ltd.
30 Worthing Rd. HORSAM, UK. (Do not post address!)

Web page:

Trough (parabola and Fresnel) and Tower systems are very well known methods of using solar power and generate electricity. These systems currently work and produce energy in many countries around the world and new ones are built regularly. They are operated with Molten Salt that functions as a Heat Transfer Fluid to store the energy, what sun-collectors collect in sunshiny hours.

Our patent is a new Heat Transfer Fluid (from here: HTF) called SULFAD that mainly contains sulphur and a small percentage of catalyst. We would like to show you the advantages of SULFAD which are beyond the increased capacity of a power station.

CSP systems have been used in the past 30 years all over Europe, the Middle East and in the US. There are two types of these systems: Parabolic and Tower. Parabolic Troughs are now operated with Fresnel-trough that applies the more cost effective flat mirrors instead of parabolic ones. The currently used HTF is Molten Salt in both Tower and Fresnel-trough Systems.

Pipes in the trough cannot bear more than 500C (773K) heat. Towers could put up with more, but Molten Salt cannot be heated above 680C because it resolves to nitrogen and other compounds.

Sulphur is an element that can be used to transfer heat. Its melting point is 119C and its boiling point (when it turns into gas) is on 444.6C, where it’s eight atoms will gradually disintegrates to six-four and finally 2 atoms. Sulphur can be heated up to 1300C and can be stored on this temperature in ceramic and fireclay chamott containers as they can bear that high temperature.

This advantage of Sulphur as HTF opens up a range of new opportunities in the operation, capacity and profit earnings for solar businesses. I would like to feature some of these below.

The concept of utilizing liquid and vapor phase sulfur in Combined Trough and Tower Systems

We combine Trough and Tower systems for our operation as it is presented on the two images below. It is ideal because gas and liquid sulphur cannot be stored in the same space. The liquid would likely block the way of the gas. Hence liquid HTF is travelling in the Parabolic Trough until it heats up close enough to its boiling point when it can travel up to the tower as gas. To generate electricity this gas will be cooled down with water which transforms into steam by the HTF’s heat. The steam than rotates a turbine to generate electricity.

The main differences between the two system’s characteristics, besides their appearance, are the level of solar energy concentration (10-100 for trough systems and 600-2000 for tower systems) and the temperature level (~670K for trough systems and ~900K for tower systems).

Unlike Molten salts, sulphur is an element; therefore, it will never decompose at any temperature. It is non-corrosive, and can be safely stored and/or transported both in liquid and gas phase in carbon steel equipments.

Another advantage of applying sulfur as a heat transfer is that its boiling point is relatively low, it is 717,6 K at atmospheric pressure, 847 Kat 5 bar pressure, 993 at 20 bar pressure. Sulphur turns into gas on a low temperature and as it is only going back to a solid phase on 119C, it is less likely to numb into the pipe. Molten Salt is crystallized already on 280C.

Comparing the mass flow rates, given in equations between Molten Salt and Sulfur, it can be stated that to achieve the same capacity of power, there is 37% lower mass flow rate is needed of sulphur than of Molten Salt. For example in a 10 MWe tower 320 tones/hour Molten Salt needs to circulate, while only 200 tones/hour sulphur will supply the same capacity. Also, the market price of sulphur (400 USD) is less than Molten Salt’s (1500 USD). The investment to the combined tower is 20-25% cheaper.

Electric power generated and stored 24 hours a day

In the combined system HTF can be transferred in two directions. 70% can produce electricity and 30% can be transferred into a special tank during sunshiny ours where it will reach 1300C. This can keep its temperature in the tank for up to 5 days. The tank must be a metal tank with a ceramic layer to bear the heat and the pressure, as in the tank gas will be compressed to keep the temperature high. This is the gas law of Gay Lusac and Boyle-Mariott: V x P/T =constant. (V=volume, P=pressure, T=temperature).

This means that a 24 hour electricity production is guaranteed, while Molten Salt operated towers can only store energy for up to 6 hours after sunset.

When the power station is close to the sea, the tower system can be used for desalination of saline water, creating drinking water.

The currently used methods for desalination of saline water are expensive, as they are carried out as an individual project.

Desalination however can be a part of electricity production.

In a CSP project water is needed to cool down the heat-transfer fluid. At these times hot and high pressured steam arouses that turns the turbines. After the steam completed its task, it can be cooled down with saline water in vacuumed condenser units (where water boils only on 60C). As a result, salt will aggregate from clean drinking water.

The blue compensators’ are the seawater recovery from salt.

Recycling metals

We can recycle metals in the combined parabola and tower systems. On picture number 3 there is a tank marked with number 15. In this tank the Heat Transfer Fluid is 1300C. If it is directed into a coquille that contains metal it will melt it.

Creating Insoluble Sulphur

In the combined system HTF can be transferred in two directions. 70% can produce electricity and 30% can be transferred into a special tank during sunshiny ours. If we add more catalyst to this 30% and cool it down suddenly we gain insoluble sulphur. It’s current market price is 1600-1800 USD/tonne and it is used for tire making all over the world.


Electric power is guaranteed over 24 hours a day

One of the biggest challenges of current CSP operations is to find a solution for a 24 hour operation. Since SULFAD can be stored on 1300C for up to five days, it can mean a breakthrough in the industry.

By using Sulfad, not only the visible heat of the fluid but the latent heat of evaporation is also utilized. Thus, due to higher thermodynamic efficiency of power generation at higher temperatures (1000°C grade), approximately 20% more electricity can be produced with the same solar energy input current HTFs use.

SULFAD creates opportunities for extra profit earnings through collateral functions

1300C mean a lot more income opportunities than just profits on electricity production. On this temperature metals can be recycled into products, water can be desalinated for drinking water production, or insoluble sulphur can be created for tires and other rubber industry products. All this can be done as a collateral function at the same time when electricity is generated with the power the sun supplies.

SULFAD is cheap

SULFAD is a much cheaper than any other currently used HTFs, and as it isn’t corrosive, the maintenance cost of a plant is significantly reduced.

SULFAD is a green solution

Sulphur is a spin-off in the process of oil manufacturing and it is indeed difficult to find industries where most of this waste can be processed into a product. By choosing insoluble sulphur production as a collateral function, the irresponsible disposal of sulphur waste can be reduced.

Metal recycling is similarly an environmental friendly action and drinking water production would mean a relief in many parts of the world where people suffer the lack of it.


Invest your money

  • Into a brand new plant at any sunshiny part of the world

  • Into a refurbishment of an existing pant that currently operates with a different HTF

Invest your knowledge or work

If you are a manufacturer, a constructor or you can possibly relate your work to our activity in any way, we would like to hear from you.

The price of the SULFAD (sulphur and additives) 550 $/ton

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