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Document Type and Number:
WIPO Patent Application WO/2022/229998
Kind Code:
Modular system for the recovery and collection of polluted sludge from the seabed to be reclaimed with a simultaneous process for the generation of syngas and subsequent transformation into electricity for self-consumption of the system and extraction of hydrogen, nitrogen and heavy metals. This new system has been studied to carry out fast, efficient and effective remediation with significant savings being a modular sludge collection plant using a robotic system with a subsequent procedure for the generation of a synthesis gas, capable of accepting as input a solid organic material having variable size, format, content of humidity and calorific power value, in order to be able to manage the widest bulk and type of incoming materials at the lowest possible cost and with an environmental impact close to zero.

Application Number:
Publication Date:
November 03, 2022
Filing Date:
April 27, 2022
Export Citation:
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International Classes:
E02F3/88; B09C1/00; B63B35/32; C02F11/10
Domestic Patent References:
Foreign References:
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[Claim 1 ] jModular system for the recovery of polluted sludge deposited on the seabed in areas to be reclaimed with subsequent transformation and production of syngas, hydrogen and nitrogen composed of:

A system for the aspiration of sludge through a bell-shaped casing made of metal or polymer with a diameter ranging from 30 cm to 500 cm, robotic and remote controlled connected to a sorbonne, made up of a pumping system which creates the vacuum inside the bell itself, which in turn accelerates and controls the sludge flow that reaches the screening and collection system via a flexible pipe

A reception stage of the sludge in the plant where the sludge is stored in tanks for a predetermined period of time

A system for the subsequent transfer of the sludge stored into a recovery plant with a water dosage controlled by a control unit functional to the type of incoming materials

A primary gasifier

A secondary gasifier

An HCL absorber (Scrubber)

An H2S absorber

An HE PA filter

An Activated Carbon Filter


A hydrogen and nitrogen extraction system

[Claim 2] Plant according to claim 1 , characterized in that electric motors are connected to the sludge extraction bell, with tilting propellers capable of detaching the bell from the bottom, and moving and repositioning the bell

[Claim 3] Plant according to claim 1 , characterized in that the system is provided with a screen selector of materials and with dryers and liquid, solid and muddy parts separators


SUBSTITUTE SHEETS (RULE 26) [Claim 4] Plant according to claim 1 , characterized in that the secondary gasifier uses a plasma torch.

[Claim 5] Plant according to claim 1 , characterized in that the stage for hydrogen extraction comprises a double system both steam reforming and conductive dense metal membranes

[Claim 6] Method of treatment of sludge coming from water treatment and contaminated sludge process consisting of the following phases:

Aspiration of sludge polluted from the seabed by bell

Store sludge in special tanks for a fixed time

Partial drying of the stored sludge with recovery of the excess water

Submit the partially dried sludge to energy recovery treatment throught gasification process

Utilization of synthesis gas generated from gasification for combustion in endothermic motors or turbines in order to produce electricity

Use a predetermined portion of syngas to extract nitrogen and azote

Vehicle hydrogen and nitrogen produced into existing gas methane pipes or store it in tanks

[Claim 7] Procedure according to claim 6 wherein the gasification process takes place via plasma torch!







[0001 ] The present invention refers to a modular system for the recovery and collection of polluted sludge from seabed to be reclaimed with a contextual process for the generation of a synthesis gas (syngas) and subsequent transformation into electricity for self-consumption of the plant itself and extraction of hydrogen, nitrogen and heavy metals.

Technical Field

[0002] The field for which the patent application is devised is the environmental remediation and restoration of marine areas or seabeds contaminated by hydrocarbons and derivatives directly on the site as required by art. 252-bis of Legislative Decree 152/2006, especially SIN . Sites of preeminent public interest for industrial conversion ". It provides that, with one or more decrees of the Minister for Economic Development, the following are identified:

[0003] The system is applicable to industrial areas where disposal of industrial waste, ELTs, exhausted oils, MSW, oil extraction waste from oil wells, wells and bituminous lakes, bilge water, biomass, etc. are necessary

Background Art

[0004] Currently, for the remediation of polluted marine areas there are no integrated systems or processes for the recovery of sludge directly from the site of provenance. Currently, remediation involves several steps, i.e. manual collection with mechanical systems, transport of contaminated sludge with heavy vehicles to incinerators or landfills for disposal or incineration. The entire chain is therefore expensive, complex and long with the risk of polluting materials leaking into the surrounding environment. These circumstances require long and complex l

SUBSTITUTE SHEETS (RULE 26) bureaucratic authorization procedures. Furthermore, traditional options do not allow the recovery of heavy metals and inert and destruction through traditional incinerators is a highly polluting process.

[0005] The applicant raised the issue how to optimize the treatment and disposal of such polluted sludge and by virtue of the present problems at the state of the art, that make remediation activities difficult, a system was studied that overcomes these problems in order to be able to carry out fast, efficient and effective remediation with significant savings in costs and risks for the environment, in order to reduce significantly the quantity and danger of sludge in landfills, recovering the thermal energy contained necessary for self-sustenance of the process without the addition, therefore, of external auxiliary fuel and no contextual recovery of hydrogen, nitrogen and inerts.

[0006] The present invention provides for the construction of a modular sludge collection plant by means of a robotic system with a subsequent procedure for the generation of a synthesis gas capable of accepting as input a solid organic material having a size, bulk and a content of humidity and power variable calorific value, i.e. without the need for any waste pre-treatment system, apart from the dosage of the waste water itself, in order to be able to manage the widest matrix and type of incoming materials (polluted sludge of the seabed) at the lowest possible cost and with an environmental impact close to zero.

Furthermore, the plant and the process of the present invention have as an objective obtaining recovery by-products from this process, namely: recovery of heavy metals, crushed stone, salt, hydrogen and nitrogen. All this with a compact, modular and energetically self-sustaining system, but above all achievable within the same area to be reclaimed, thus cutting all the intermediate steps of transport and transfer to landfills or incinerators mentioned above.

Disclosure of Invention

[0007] The system is modular and can be replicated, with a disposal capacity that can be adapted to the specific needs of the remediation project, with efficiency and performance superior to current incineration technologies, thus allowing the


SUBSTITUTE SHEETS (RULE 26) recovery of metals and inert waste (gravel, crushed stone), hydrogen and nitrogen, which can be marketed or reused for various purposes.

[0008] The invention to be patented is simple and innovative and consists of an integrated process (FIG.1-2 ) divided into the following phases :

[0009] Through a special robotic system, polluted sludge (which mainly contains hydrocarbons, oils, sludges and heavy metals) is recovered from the seabed

[0010] Water is separated from the mud by drying in special tanks

[0011] The remaining mixture of mud and pollutants is fed into the recovery plant

[0012] The process of gasification of organic material is started with dosage of temperature, waste water and pressure in a specific environment, accelerating what normally occurs in nature, thus obtaining synthesis gas

[0013] Part of synthesis gas is utilized for extraction of hydrogen and nitrogen and the remaining part can optionally be used as fuel for engines or turbines for the recovery of electricity that will power the plant

[0014] The hydrogen extracted is conveyed to gas / methane pipes or stored in tanks

[0015] The syngas recovered from the polluted sludge, composed mainly of highly polluting hydrocarbons, transform the waste into a resource within the same reclamation area, at no cost with the recovery of heat, electricity, hydrogen, nitrogen, salt, aggregates and metals, but also without emissions into the environment, anticipating the restrictive regulations on the subject.

[0016] Using the high energy contained in the plasma, the organic waste molecules (in a reaction zone where the temperature ranges from 3000° to 4000 ° C) are decomposed in the presence of water vapor, thus producing a synthesis gas (syngas). The syngas is utilized for the production of electricity or for the extraction of the elements of which the syngas itself is composed.

[0017] The energy contained in the synthesis gas, after a proper washing, is recovered in different ways:

[0018] Total recovery of the chemical components of the syngas (extraction of hydrogen, nitrogen and inerts)


SUBSTITUTE SHEETS (RULE 26) [0019] Production of electricity by means of gas engines / turbines for integration to the power supply of the plant itself

[0020] Regulations. The scope of the activity falls within the scope of the provisions of Legislative Decree n. 46/2014, issued to supplement law no. 152/2006, as subsequently amended, defining a regulatory context that radically affects the approach to environmental and energy issues.

[0021] Process description


[0023] 1) The area to be reclaimed is delimited with a checkerboard system by immersing bulkheads in the water in order to avoid product leaks from the work area. The area boundary bulkheads can be made of metal or polymer (Fig. 3-4)

[0024] 2) Into the delimited space a steel or polymer robotic bell with a diameter between 30 and 500 cm is immersed, to which a sorbonne is connected, which through a vacuum system, sucks all the sludge from the bell until it reaches the desired depth.

[0025] 3) These sludges are pumped from the bell to draining boxes, vibrating filter bed, boxes collecting coarse material, vibrating screen with pumping system.


[0027] The drained sludge, consisting mainly of hydrocarbons of different nature, and water are conveyed and stored in storage tanks where a separation phase takes place, through which the drained sludge undergoes a partial drying process and is separated from the water, obtaining mud and water. The residual water will be stored in special tanks for subsequent reuse.



SUBSTITUTE SHEETS (RULE 26) [0029] Muddy sludge is conveyed to the recovery plant. A special dispenser controlled by a control unit will dose the ratio between water and sludge, functionally to the characteristics of the hydrocarbon present inside and its consistency (Fig . 5 ). The excess water will be recovered and sent back to the system. The recovery with relative inertization of the polluting substances takes place through a process of thermochemical decomposition of organic and inorganic substances in the absence of oxygen.

[0030] The peculiar characteristics of the process are to combine in a single compact integrated system: (i) the molecular decomposition process at high temperatures, (ii) the advanced gasification, (iii) the subsequent vitrification of residues into inert material, gas cleaning and recovery of hydrogen and nitrogen.

[0031] Gasification is the reaction process of the organic fraction with FI20 and a limited quantity of air appropriately dosed for the production of a synthesis gas containing mainly CO and H2.

[0032] The synthesis gas (syngas) produced is further washed and used for the production of energy through gas turbines or reciprocating internal combustion engines. The hot water and steam generated are utilized in a combined energy co generation cycle, within the entire process.

[0033] Vitrification is the process by which the inorganic fractions of the treated substances are permanently trapped in the vitrified waste and which are usable in a variety of commercial applications.

[0034] 3.1 Gasification and vitrification

[0035] Primary gasification and vitrification (Fig. 8)

[0036] Thermal conversion of organic matter into syngas consisting mainly of CO and H2.

[0037] The organic fraction of the material leaves the primary gasification furnace as raw synthesis gas, consisting mainly of CO and H2, but also containing a certain amount of carbonaceous soot, acid gases, moisture and partially decomposed


SUBSTITUTE SHEETS (RULE 26) hydrocarbons. The synthesis gas leaves the primary gasifier at a temperature of about 700 ° C.

[0038] Inorganic materials are melted and produce inert slag that can be used safely in various applications.

[0039] An inert slag is produced, whose release properties are much lower than the limits imposed by the TCLP ( Toxicity Characteristics Leaching Procedure ).

[0040] The molten material (slag), the temperature of which is maintained above 1550 ° C, is poured by an automatic system and recovered as an ingot or transformed into granules.

[0041] Granulation is achieved by rapidly cooling molten slag with water, which, once vitrified, is 10 times harder than concrete and can be used in a variety of commercial applications.

[0042] Other dangerous inorganic substances remain permanently trapped in the vitrified slag.

[0043] b) Secondary gasification

[0044] The raw synthesis gas is sent to a secondary gasifier, heated by a plasma torch to over 1 ,000 ° C.

[0045] The secondary gasifier is essentially a plasma eductor , designed to mix the raw syngas flow with air and moisture and expose this highly reactive mixture to the extreme plasma temperatures. This process ensures that all complex organic molecules and soot particles are converted into CO and H 2

[0046] The synthesis gas leaving the secondary gasifier is cooled with water, from over 1000 °C to less than 100° C in less than 0.5 seconds. In this way the composition of the hot gas is maintained and the formation of dioxins, furans or other complex molecules is prevented. This process completes the heat treatment and gives rise to convert the treated material into three products of marketable value: metal, crushed stone and fuel.

[0047] This process called PRRS (Plasma Resource Recovery System) has many advantages over incineration. The incineration produces large quantities of clinker, fumes and dust while the PRRS process of gasification and vitrification does not produce solid waste because all the inorganic material is converted into inert slag


SUBSTITUTE SHEETS (RULE 26) and metal ingots, the treatment of the fumes is eliminated and the transfer to landfill of secondary materials practically zero.

[0048] Incineration involves the use of large quantities of caustic soda, lime, urea and activated carbon to treat acid gases ( HCI , SOx , NOx ), heavy metals, mercury, dioxins and furans. In the PRRS process, NOx formation is almost completely inhibited because chemical reactions take place in a reducing atmosphere.

[0049] Dioxins and furans are almost non-existent in the gasification process since the temperature is far above the critical temperature range and all thermal reactions occur in a reducing atmosphere. Furthermore, the rapid cooling maintains the high thermodynamic equilibrium of the system, preventing the reformation of dioxins and furans.

[0050] Between this phase and the subsequent washing of the syngas, the system is interfaced and connected to the hydrogen and nitrogen extraction system as better described below.

[0051] Syngas cleaning system ( Fig. 9)

[0052] The synthesis gas is subjected to a series of integrated subsystems:

[0053] Quenching

Provides rapid gas cooling

Prevents the formation of dioxins and furans

[0054] Venturi

Removes coarse particles

[0055] FICL absorber ( Scrubber )

Neutralizes HCI [0056] H 2 S absorber Removes Sulfur [0057] HEPA filter Removes fine particles [0058] Activated Carbon Filter


SUBSTITUTE SHEETS (RULE 26) Removes volatile heavy metals


Keeps the system under constant negative pressure Prevents any fugitive emissions

[0060] Energy and hydrogen recovery (Fig. 10)

[0061] The energy contained in the clean synthesis gas is recovered in different ways:

[0062] Production of hydrogen and nitrogen by steam reforming and combined membranes

[0063] Possible production of electricity by means of gas engines / turbines as an integration for the power supply of the plant itself

[0064] Extraction of hydrogen and nitrogen (Fig. 11 )

[0065] The extraction of hydrogen and nitrogen takes place through a double steam system combined membrane reforming .

[0066] Observing only the H2 production, membranes have an efficiency that can reach 76,5%.

[0067] Steam-reforming systems : membranes

[0068] Membranes are selective gas separators, i.e. devices that remove a single type from a gas stream, using as the driving force the difference between the partial pressure of the specie between the feed side and the extraction side (permeate side).

[0069] The gas fed is divided into two fractions: one containing the removed species (permeate) and one containing all the other species ( retentate ): to decrease the partial pressure of the permeate it is possible to feed a " sweep gas", that is an inert (generally N2) which, by diluting the species involved in the separation, decreases its concentration.

[0070] The use of sweep gas allows to obtain high efficiencies with small membrane surfaces.


SUBSTITUTE SHEETS (RULE 26) [0071] The main characteristics of a membrane are:

Ability to process a large flow rate at the interface

Stability during the operating conditions

Resistance to contaminants

High selectivity

Ease of manufacture

Low cost

[0072] To perform the extraction of hydrogen from syngas 2 types of membranes have been used in parallel, that will be used according to the characteristics and temperatures of syngas. Membranes for the selective separation of hydrogen are of different categories, depending on the construction technology, materials and operating temperatures:

Dense metallic membranes

Conductive membranes

Dense metallic membranes

[0073] Metallic palladium membranes with a porous ceramic substrate based on zirconium, vanadium and niobium work in a range between 300 and 600 ° C.

[0074] The functioning of dense metallic membranes is based on a “solution-diffusion” mechanism.

[0075] Conductive membranes

[0076] On the supply side, the dissociation of hydrogen into protons and electrons takes place, as in dense metallic membranes; H+ and e- are then transported across the membrane and recombined on the permeate side. The interface processes charge transfer reactions.

[0077] The selectivity of hydrogen is very high (> 99%) and therefore a subsequent purification of the permeated flow is not required. The hydrogen produced can be stored or conveyed inside methane gas pipes.


SUBSTITUTE SHEETS (RULE 26) Advantageous Effects of Invention

[0078] Use of small areas where everything extracted from the polluted seabed is immediately transformed and recovered entirely (Fig. 7)

[0079] Innovative high efficiency technology

[0080] Possibility of selling the recovered product (hydrogen and nitrogen) to neighboring refineries or on the market (bottled or through piping) for the needs of local needs

[0081] Reduction of the dispersion of contaminants during the sludge recovery phase

[0082] Reduction in the consumption of water resources as the same waste water from the sludge is reused

[0083] Abatement of water discharges

[0084] Reduction of the quantity and danger of special waste present in the area

[0085] Zeroing of gaseous emissions into the atmosphere

[0086] Integrated monitoring carried out continuously

[0087] Normal activity during recovery operations is not interrupted and is not compromised if the reclamation is to be carried out in areas such as ports, refineries or industrial areas.

Brief Description of Drawings

[0088] The drawings attached to this patent application show the scheme of the process, the main components of the system and the process described here.

[0089] Fig. 1 shows the general flow of the contaminated sludge up to its complete recovery.

[0090] Fig. 2 shows the general layout and the scheme of the system showing the sludge collection stage by means of a bell with a vacuum system and the connection with the screening, storage and recovery system.

[0091] Fig. 3 shows the detail of the sludge collection system with bell and caissons specifically composed of the following parts: 1) pumping system; 2) water


SUBSTITUTE SHEETS (RULE 26) drainage; 3) container for the collection of coarse material; 4) vibrating screen; 5) draining caissons; 6) filtering vibrating bed; 7) sludge collection bell

[0092] Fig. 4 shows the detail of the bell designed for the collection of sludge. Specifically is shown: 8) connection pipe; 9) motorized bell; 10) delimitation bulkheads

[0093] Fig. 5 shows the detailed layout of the recovery and transformation of sludge into syngas and hydrogen by means of primary, secondary gasifier, gas cleaning system and hydrogen and nitrogen extraction system consisting of the following parts: 11 ) contaminated sludge inlet; 12) water dispenser; 13) primary gasifier; 14) secondary gasifier; 15) gas cleaning system; 16) plasma hydrogen extraction system with membranes; 17) gas turbine; 18) internal combustion engine

[0094] Fig. 6 shows the typical chemical composition that can be found in contaminated sea beds containing a significant amount of hydrocarbons.

[0095] Fig. 7 is an example of the proposed system as regards to a mobile system placed on a self-moving container are shown.

[0096] Fig. 8 shows the exploded view of the primary and secondary gasifier with their main components specifically: 19) graphite electrodes; 20) output of the raw syngas; 21 ) voltage input; 22) hole for the collection of molten slag; 23) refractory insulation; 24) primary gasifier; 25) secondary gasifier; 26) plasma jet; 27) heat treatment area; 28) synthesis gas; 29) pretreated material.

[0097] In Fig. 9 the process scheme of cleaning the raw syngas is shown

[0098] Fig. 10 there is an example of a mass balance with a pilot plant of 3,000 tons / year.

[0099] Fig. 11 shows the hydrogen extraction system connected to the recovery plant consisting of the following parts: 30) Reactor; 31 ) catalyst); 32) term insulation; 34) high temperature thermal insulation; 35) steel; 36-37) secondary inlet and exit ; 38) heat exchanger

Industrial Applicability

[0100] This system arises from the need to optimize and make the most of the recovery of materials and resources from waste / by-products and the remediation of contaminated sea beds, in compliance with the recent European Community


SUBSTITUTE SHEETS (RULE 26) regulations, which require Member States and manufacturing companies an adaptation for the protection of health and the environment, exploiting and integrating the most advanced technologies, with the aim of reducing emissions and obtaining the maximum recovery of material and energy. The proposed system makes it possible to fully recover the waste / by-products within the areas to be reclaimed.

[0101 ] Thanks to the system and the applied technologies, a modular system has been set up, with a disposal capacity that can be adapted to the specific remediation needs. This system is aimed at collecting, recovering and transforming all polluting materials, from organic materials with a high presence of hydrocarbons to contaminated inerts, up to metals and heavy oils (typical composition of contaminated marine mud.