WO2009136181A1

WO2009136181A1 - Method of purification of glycerine

Info

Publication number: WO2009136181A1
Application number: PCT/GB2009/050316
Authority: WO
Inventors: Bai Leng
Original assignee: Bai Leng
Priority date: 2008-05-07
Filing date: 2009-03-31
Publication date: 2009-11-12
Also published as: GB2459738A; GB2459738B; GB0808248D0

Abstract

The present invention relates to a method for purifying glycerine, by means of combination of physical processes. The present invention also relates to number of apparatus for purifying glycerine.

Description

METHOD OF PURIFICATION OF GLYCERINE

DESCRIPTION

The present invention relates to a method and apparatus for purifying glycerine. Distillation is a widely used technique for the purification of a number of liquids, including glycerine. Distillation of glycerine can produce high-grade glycerine of up to 99.7% of purity. To reduce energy costs of distilling glycerine (which has a boiling point of 290⁰C), very high vacuum conditions arc often employed to distil the glycerine at a lower temperature. However, providing such a vacuum is expensive to implement and service. Despite the boiling point of glycerine being lowered by means of a vacuum, the energy costs remain high and it is the major costs of the glycerine purification. Furthermore, it is widely believed that when glycerine is heated over 150 ^QC, it decomposes and produces acrolein (acraldehyde, or prop-2~enal), which is known to be poisonous. Glycerine is used in many industries, each of which requires different purity profiles. For example, the pharmaceutical industry requires extremely pure glycerine, whilst other non-tbod, non-pharmaceutical and non-cosmetic industries arc less stringent.

Glycerine of natural sources is produced as a by-product in a number of industries, such as during the production of soap, oleochemicals and bio-diescl. Bio-diesel production is now the major source of crude glycerine and the quality varies widely from producer to producer. Crude glycerine from biodiesel productions contains higher organic and inorganic impurities. Ionic impurities can be as high as 7-10%; water content can be as high as 15-20% or over, whilst organic impurities (MONG, materials organic non-glycerol) can be as high as 10% or over. It will be evident that the production of bio-diesel will increase as it is a more environmentally friendly fuel and reduces the dependence upon crude oil based fuels, and it follows that an increase in the production of surplus of glycerine will be experienced, Oleochemical production is the traditional source of crude glycerine and tends to produce crude glycerine of a higher quality. Crude glycerine from oleochemical producers contains high glycerol with lower organic and inorganic impurities and lower water content. Soap production is another traditional source of crude glycerine, but the quality is often poor and yield quantity relatively small.

Artificially-composted glycerine and glycerine obtained from fermentation (zymotcchnics) are other sources of glycerine. Artificial-composted glycerine was made from fossil oil, but volumes have greatly reduced in recent years due to high costs and the availability of glycerine from bio-diesel production. Fermentation (zymotechnics) was developed late last century and has not been widely adopted since. It uses agriculture products or agriculture wastes, such as cobs of corns as raw materials. Glycerine produced by zymotechnics contains very low glycerine and large amounts of bio and organic impurities and large amounts of water, requiring further concentration and purification. Residua left over from glycerine distillations is a mixture of organic and inorganic materials, the mixture of both having almost no commercial value and are difficult to separate. The residua produced in industrial glycerine processing plants is often in fairly large quantities. Such waste presents an environmental problem due to its nature of mixed organic and inorganic content. CZ284042 discloses a process of retrieving crude glycerine from industrial waste or solution containing very low levels of glycerine by means of a membrane. GB2437516 discloses a method for substantially purifying glycerine from liquids comprising passing the liquid through one or more filter membranes and a deionisation means. Whilst this method has proven successiul in purifying glycerine, it has been found that over time, the membranes can loose efficiency due to becoming blocked or fouled with impurities - such as fatty adds and/or esters.

It is an object of the present invention to overcome or alleviate one or more of the problems associated with the prior art.

Iu accordance with the present invention, there is provided a method for substantially purifying glycerine from liquids, the method comprising the steps of passing the liquid through one or more gravitational separation stages.

The present invention therefore provides for a low cost, energy efficient, low wastes and environmentally friendly and flexible processing technique, wliich can be used in the purification of glycerine as well as the treatment and recycling wastes. Advantageously, the present invention may provide a method of purifying glycerine, without the need for high temperature distillation and/or extreme low pressure vacuums. In addition, the present invention may provide a method of purifying glycerine, which is preferably both energy efficient and environmental friendly. Furthermore, it would be advantageous if the method would be able to purify glycerine to a pre-determined purification profile. - A -

The term "substantially purify³' is intended to mean the removal of some or the majority of impurities in a given liquid containing glycerol, which may or may not also include solvents, if the liquid is a solution. The term is also intended to refer to the refining of liquids containing glycerol, which may usually take place by means of distillation etc.

The use of liquid-liquid separation by means of gravitational separation enables glycerine purifications to be controlled precisely. The purified glycerine can be produced at a flexible manner not available before or in the past with different grades, such as animal feed grade, technical grade (in many sub-grades), food and pharmaceutical grade, etc, so as to match customers' requirements. Such manageable product grade selectivity in glycerine purification allows the glycerine producers additional benefits in cost savings, production efficiency and customer satisfaction. Additionally, the present invention also provides for a low costs, energy saving and an environmentally friendly method for the purification of glycerine having:: (1) low equipment cost; (2) low production cost; (3) significant energy saving; and (4) reduced waste (wastes separated during the method can be turned into valuable commodities).

The term "gravitational separation" is intended to include separation techniques such as floating, coalescence, accelerated ultra-high G-force (gravitational force) separation and solvent extraction and washing techniques.

Preferably, the one or more gravitational force separation stages comprises accelerated ultra-high G-forcc separation (AUHGS) and natural gravitational separation (GS). More preferably, the AUHGS induces the displacement of crude glycerine solution such that the components thereof can be separated according to specific gravity difference between the materials mixed in liquid, such as by ultra- centrifugation. Typically such separation techniques arc carried out at ultra-high speeds giving ultra-high centrifugal separation factors. Centrifugal separation factor (CSF) describes amount ofcentrifugal force applied to liquid or mass and it can be calculated by:

mRω² Rω²

Fc = = — —

or approximated by: Centrifugal Force x Density, such as Fc = 0.00007118rN²m where: Fc: centrifugal separation factor m: density of the liquid (g/cm³)

R: radius of the centrifugal apparatus (M) ω: angular speed of accelerated liquid (r/s) g: acceleration of gravity (9.8 lm/s²) r: radius of the centrifugal apparatus (cm) N: rotating speed (rpm) for example: 80% of glycerine (density = 1.22) is accelerated to a speed at 20,000 rpm in a centrifugal container with 200 mm inner diameter. Maximum CSF of the liquid is:

CSF_{(se%clyceφκ)} = Q.00001118 x lOx 20000² xl.22 = 54558

where, maximum CSF of fatty acids and esters (FAEs) (i.e. density = 0.88) in the crude glycerine liquid is:

CS^Fv>m*w = 0O00011I8 x lO x 20000^s x θ.88 = 39354

where, maximum CSF of protein or large molecule organic impurities (i.e. density = 1.01) in the crude glycerine liquid is:

CSF_(FBHyAcids) = 0.00001118 x lO * 20000^{2 χ} l.01 = 45167

undeT the same AUHGS process, 80% crude glycerine is accelerated to have maximum 54,558 times of separation force than its natural density, while FAEs in the glycerine liquid only gain maximum 39,354 times of separation force due to 28% lower density than that of glycerine liquid, and 45,167 times of separation force tor protein or large molecule organic impurities due to 17% lower density than that of glycerine liquid. MONG are separated from glycerine liquid by AUHGS process.

It is widely accepted that AUHGS is able to achieve liquid-liquid and liquid-solid separation at as little as 1.0% (0.01) of density differences.

In one embodiment, it is preferred that the AUHGS stage comprises accelerating the liquid containing glycerine to speeds having CSFs in the range of

5,000 to 60,000 or higher. It is more preferred that the centrifugatioii 'Stage comprises accelerating the liquid to speeds having CSFs in the range of 12,000 to

50,000. Most preferably, the centrifugatioπ stage comprises accelerating the liquid to speeds having CSFs in the range of 15.000 to 30,000. Any intermediate ranges of CSF may also be employed in the present invention, for example, 5,000 to 10,00O₅ 5,000 to 15,000, 5,000 to 20,000, 5,000 to 30,000, 5,000 to 40,000,

10,000 to 15,000, 10,000 to 20,000, 10,000 to 30,000, 1 O₅OOO to 60,000, 15,000 to

20,000, 15,000 to 30,000, 15,000 to 60,000, 20,000 to 30,000, 20,000 to 40,000,

20,000 to 60,000, 30,000 to 40,000, 30,000 to 60,000 or 40,000 to 60,000 It is preferred that the one or more AUHGS stages comprises accelerating the glycerine solution to speeds having the same or two or more different CSFs for a given period of time. In one embodiment, where the one or more AUHGS stages comprises centrifugation depending on the purity requirement, the liquid may be accelerated to a speed having the same or similar CSF for a given period of time or a lower CSF for a given period of time or accelerated to a speed having a higher CSF for a given period of time. Thus, the centrifugation stage may comprise a number of steps, each step having a manner of incremental CSF increases or decreases, or all kept at the maximum CSF that equipment allow. For example, the centrifugation stage may comprise a first step of accelerating the liquid to a speed having 5,000 CSF, a second step of accelerating the liquid to a speed having 12,000 CSF and a third step of accelerating the liquid to a speed having 15,000 CSF or 20,000 CSF or higher and so on, or all stages working at the same CSF such as an optimised CSF or the maximum CSF. The discrete steps will preferably be applied to the liquid sequentially. If desired_> the discrete steps of differing speeds may be applied to a single centrifugal apparatus, or undertaken in different centrifugal apparatus connected in series. Tt is to be understood that "a given period" of time is intended to mean a length of time for which the accelerated liquid is intentionally working at a constant centrifugal separation factor. It is preferred that one or more AUHGS stages arc performed in continuous feed liquid centrifugal apparatus, such as, for example, tubular centrifugal apparatus. Such apparatus will be known to the artisan skilled in the art and it will be apparent that the MONG will be separated by the ccntrifugation step, which can be removed via a controlled light phase outlet, whilst the heavy phase containing the cleaner crude glycerine can be removed via a controlled heavy phase outlet. It is to be noted that the present invention, in instances where centtϊfαgation is used, is the opposite to conventional wisdom and conventional use of centrifugation. In the present invention in such instances, the main liquid body (glycerine solution) is collected and thimbleful/minority matter is discarded as impurity in contrast to conventional wisdom where the thimbleful/minority content is usually the product to be extracted/enriched and recovered.

AUHGS can be by any suitable means. Essentially, displacement acceleration of the liquid must take place and this can be induced by use of centrifugation concept. The vessel within which the liquid is contained during AUHGS may or may not move at the same speed as the displaced liquid. The vessel may run at the same speed of the displaced liquid, or a speed slower than the speed of the displaced liquid, or may not move at all relative to the displaced liquid.

It is preferred that the method comprises at least three gravitational separation means and one solvent extraction and washing means in parallel each of them either works individually and independently or works in coordinate with one of the two others or all together.

For the three gravitational separations, one of them comprises AUHGS, such as centrifugation, and the other comprises coalescence and/or floatation.

More preferably, the first stage comprises AUHGS or coalcsccnt filtration or floating means being a primary gravitational separation or comprises solvent extraction and washing process (SEWP), and all of the four primary separation methods followed by an optional MONG fine stripping stage, which is a fine coalescence process and/or with FAEs absorption process and/oτ solvent extraction and washing process.

A coalescer is a "filter type" device. Its fimction is to catch and merge suspended and/or dispersed and/or emulsified micro-droplets of FAEs containing in crude glycerine solution and to allow the micro-droplets to collide into each other to merge or grow to larger drops. When the droplets grow sufficiently large, they gain gravitational force to separaLe themselves from glycerine phase due to gravitational differences and immiscibility of the two mixed liquids. A coalescent filtration means may comprise a filter. A coalescent filter is also known as a "Coalesccr". It works on the basis of "Coalescence". Tn the present invention, the feed stock is preferably pre-processed to remove large particles which may foul the coalescer. The use of AUHGS also removes such particles from the liquid. Coalescence is a process in which two phase domains of essentially identical composition come into contact with one other and form a larger phase domain. Coalescence typically comprises passing a sample through one or more coalescenl filters, such as a deep-bed fibre matrix, where impurities in the sample arc intercepted when they impact fibres of the matrix. Surface tension causes the impurities to be captured by the capturing fibres and to collide each other. As more droplets impact those already captured, they continue to grow together or coalesce until the droplets reach such a mass and size that they dislodge from the capturing fibres and as the heavier or lighter of the two phases rise or drop with gravity. There will then be a two phase liquid and either phase can be recovered

The method preferably comprises one or more coalescent filtration stages. Each coalescent filtration stage preferably comprises passing the liquid through a coalescent filter.

The method preferably comprises one or more Coalescence process in parallel with ΛUHGS processes as one of primary MONG removal means.

In accordance with a further aspect of the present invention, there is provided an apparatus for purifying glycerine from liquids, the apparatus comprising AUHGS means located in parallel with at least one coalescent filtration means. Coalescent filtration can work independently as a primary MONG removal means, or work in coordinate with AUHGS and/or other primary MONG removal apparatus for better results of MONG removal if required.

Preferably the coalescent filtration means comprises at least one micro- droplet catching matrix. More preferably the coalescent filtration means comprises a plurality of micro-droplet catching matrices. The matrices may comprise a filter having a given fibre sizes preferably in a range of 0.2μm to l.OOOμm in diameter. More preferably the fibre sizes in a range of l.Oμm - 500μm in diameter. More preferably, where there are two or more such matrices, the fibre size between successive matrices is different. Preferably the matrices arc arranged such that the liquid flows from matrices having smaller fibre size in higher fibre density to those having a larger fibre size in lower fibre density. More preferably still the fibre size and density between successive matrices is graduated. Even more preferably still, the matrix comprises a filter.

The filter may comprise a hydrophobic or hydrophilic material, or non- hydrophilic non- hydrophobic material. The filter may be in the form of an thin or thick pad or thin or thick sheet and/or further formed to any applicable shapes and sizes with one or more layers of graduated fibre matrices from smallest fibre size and packed in higher density to larger fibre size and packed in lower density. The filter may comprise any one or more materials selected from the group comprising: polypropylene fibres, ceramic fibres or ceramic powders, activated carbon fibres etc.

The apparatus will preferably be used to implement the method as herein above described. The method preferably comprises one or more solvent extraction and washing stages or SEWP in parallel with AUIIGS and Coalescence processes as one of primary MONG removal methods. SEWP can work independently from AUHGS and Coalescence processes or work in coordinate with AUHGS and/or Coalescence processes. Each SEWP preferably washes glycerine liquid with an extraction and washing agent (EWA) by well mixing glycerine liquid with the EWA. An EWA preferably comprises one or more organic and inorganic solvents or a solvent mixture of two or more organic and inorganic solvents. SEWP uses EWA to purity glycerine liquid by the concept of taking effects on all of organic impurities include colours and water. Preferably SEWP applies once or many times. SEWP can give extremely low MONG content and lighter colour. Of SEWP, the quality or cleanness of glycerine liquid can be precisely controlled by the quantity of EWA being used, time and number of SEWP being carried out. Water content of glycerine liquid can be reduced by SEWP if the EWA contains quantity of solvent which is miscϊble with water.

EWA can be just a single solvent or a liquid mixture of two or more solvents mixed together in any proportion or mixing ratio. Each SEWP comprises a single solvent or mixed EWA solution wash or many times of solvent washes or mixed EWA solution washes in a given time. SEWP can be a single solvent throughout wash or washed by one solvent or EWA and followed by another types of solvent or EWA, or any pre-determined EWA in any order and any number of pre-detcrmined washes with a given EWA to Glycerine Ratio (EGR, volume/volume) within a given time. For example, the first SEWP uses a water immiscible single solvent followed by a water miscible solvent and then followed by a mixture of EWA solution, etc with a pre-detcπnined EGR and complete each EWA wash within a given time.

In one embodiment, it is preferred that any single EWΛ wash applies EWA to Glycerine Ratio (EGR) from 1:1,000 to 200:1. It is more preferred that a single EWA wash applies EGR in a range of 1 :20 to 10:1. Most preferably, a single EWA wash applies EGR in a range of 1 :5 to 2:1. Any intermediate EGR

' ranges of a single EWA wash may also be employed in the present invention, for example but not limit to 1 :1,000, 1:900, 1 :800, 1:700, 1 :600, 1:500, 1 :400, 1 :300,

1:250, 1:200, 1 :150, 1 :100, 1 :90, 1 :80, 1:70, 1:60, 1:50, 1 :40, 1 :30, 1 :25, 1:20, 1 :15, 1 :10, 1 :9, 1:8, 1:7, 1 :6, 1 :5, 1 :4, 1 :3, 1 :2.5, 1:2, 1:1.9, 1 :1.8, 1:1.7, 1 :1.6, 1:1.5, 1 :1.4, 1 :1.3, 1 : 1.2 1:1.1, 1:1, 1.1:1, 1.2:1, 1.3:1 , 1 ,4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.5:1, 3:1, 4:1 , 5:1 , 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 25:1, 30:1, 40:1, 50:1, 60: 1, 70:1, 80:1, 90:1, 100:1, 110:1, 120:1, 130:1, 140:1, 150:1, 160:1, 170:1, 180:1, 190:1 and 200:1. The method preferably comprises floating process as a primary MONG stripping means in main purification process either applied independently or in conjunction with other three MONG stripping processes individually or coordinates. Preferably uses air or inert gases or non- inert gases or mixture of air or gases at any mixing proportions or using other solid floating materials as floating agent. More preferably uses heated or non-heated dry air or dry inert gases or non- inert gases or mixtures of dry air or gases at any mixing proportions as the floating agent. Preferably crude glycerine liquid is heated and the liquid viscosity is greatly reduced under high liquid temperature. Low liquid viscosity helps to speed up floating process and shorten the processing time. Floating process can work in coordinate with AUHGS and Coalcscent processes to improve processing efficiency. Floating process can be a continuous or discontinuous process by mixing floating agent with crude glycerine solution. Gas to Glycerine liquid Ratio (GGR, volume/volume) can be any from 1:1,000 to 200: 1. Preferably GGR is in the range of 1 :20 - 20: 1. More preferably GGR is in a range of 1:5 - 5;1. Any intermediate GGR ranges of a single floating process may also be employed in the present invention, for example but not limit to 1 : 1,000, 1 :900, 1 :800, 1:700, 1:600, 1 :500, 1:400, 1:300, 1 :250, 1:200, 1:150, 1 :100, 1 :90, 1:80, 1 :70, 1 :60, 1:50, 1:40, 1:30, 1 :25, 1 :20, 1 :15, 1:10, 1 :9, 1:8, 1:7, 1 :6, 1:5, 1 :4, 1 :3, 1:2.5, 1:2, 1 :1.9, 1:1.8, 1 :1.7, 1:1.6, 1 :1.5, 1: 1.4, 1:1.3, 1 :1.2 1:1.1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.5:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 25:1, 30:1, 40:1, 50:1, 60: 1, 70:1, 80:1, 90:1, 100:1, 110:1, 120:1, 130:1, 140:1, 150:1, 160:1, 170:1, 180:1, 190:1 and 200:1.

The method may also comprise the step of deionising the liquid to substantially remove ionic impurities (cither monovalent and/or multivalent ions). It will be evident to one skilled in the art that the deionising step may be performed using a number of means, such as captive deionisatioπ or electrodialysis and/or electrodeionisation and/or ion exchange resins techniques. The precise deionisation method and equipment will be dependent upon the liquid being purified and cost/efficiency parameters. It will also be evident that the costs/efficiency of deiouisation will depend upon the content levels of salinity/total amount of salts in the liquid under purification. In one embodiment, electric field induced dcionisation means such as eletϊodialysis and/or clectrodeionisation should be the first means of desalination because of the high efficiency and low running costs. Ion exchange can be used instead or ill addition to electric field induced desalination. Preferably, if ion exchange is used in conjunction with electric field induced desalination, ion exchange is the last dcsalinization process for extremely low salt products as ion exchange offers better cost effective in dealing with very low salt solutions. The latest available commercially Capacitive Deionisation Technology (CDT) offers low running cost to deionisation on low salinity solutions. If, for example, the liquid is crude glycerine containing high and very high salts content, such as found in crude glycerine from bio-diesel productions, clcctrodialysis(ED)/electrodeionisation (EDI) techniques offer cost effective performances in total dcionisation. ED/EDI and ED/EDI based deionisation modifications are almost the first line of choice of deionisation for the solutions with high salinity, such as glycerine liquids derived from current bio-diesel productions.

Preferably, the deionisation should be capable of removing all ionic impurities from the liquid, whilst avoiding the use of an additional deionisation processing. Modifications of electrodeionisation, which are based on the electTodialysis (ED) process, include a number of variations such as EDI (ED plus ion exchange resin membrane), CEDI (continuous EDI), EDIR (EDI frequent reversal), and/or CEDIR (continuous EDI frequent reversal), etc. may also be employed in accordance with the present invention.

The ion exchange process should be able to remove almost all of ionic impurities from a given liquid at higher deionisalion costs. De-colourise ion exchange can also be used Io decolourise the liquid. The configuration of the ion exchange system may be either single, or multiple, e.g. twin, triple etc. ion exchange column set(s). The inclusion of an ion exchange system in a deionisation process enables extremely pure glycerine to be produced. Should an ion exchange system be employed, it may also be able to provide for line deionisation after the initial purification (if required) or as a stand-by deionisation device. More than one ion exchange systems may be provided if a continuous process is required. Parallel or multiple ion exchange systems will allow switching between individual ion exchange systems. For example, if a first ion exchange system is under reconditioning, a second ion exchange system may be brought online so as to provide continuous deionisation, or vice versa. When an ion exchange set has completed its reconditioning, it can then be put on stand-by, so that it is ready to replace the other sets when due reconditioning.

Due to the nature of ion exchange resins, it is preferred that the ion exchange system is reconditioned regularly when the ion exchange resins are saturated. Ion exchange systems are often employed to work in set groups of columns filled with ion exchange resins: (1) Two column set:- a cation exchange resin column and an anion exchange resin column; (2) Three column set:- a cation exchange resin column, an anion exchange resin column and a mixed column which contains both cation and anion exchange resins; and (3) One column set:- a single mixed column contains both cation and anion exchange resins.

Decolouring or product bleaching may be required if the glycerine is intended to be used in a number of industries, such as in high-end industrial uses and in food, pharmaceuticals and cosmetics. The liquid may be subjected to polishing means. Polishing refers to decolour, de-odour and/or further fine treatment. De-colouring can take place by, for example, contacting the liquid with activated carbon or de-colouring ion exchange resins or bleaching earth which is absorbent clay that removes colours from liquid. De-odour can take place by, for example, contacting the liquid with activated carbons or other odour absorption agents. Preferably de-odour is not carried out by the use of hot steam. Preferably, polishing takes place downstream of the one or more gravitational separation stages and de-salt or de-ionisatkm processes. Deionisation ion exchange resins may contribute to "absorb" or remove some or part of colours while they remove ions out of the solutions. During the ion exchange process in the glycerine purification, final remaining ions arc removed, as well as part of the colours. Due to the "re-generation" properties of ion exchange resins, ion exchange resins can be used repeatedly over a period of time. De-colourisation ion exchange resins or activated carbon or bleaching earth and other bleaching means may also be employed if there is an additional requirement for further decolourisation. De-colouring includes many other methods and not limited to above mentioned means or processes.

The method may also further comprise the step of substantially desalinising the liquid so as to substantially remove the content of salts in the liquid.

The method may additionally comprise extreme pure processing. This preferably comprises a SEWP which applies organic and inorganic solvents to extract and wash out any possible remaining MONG including part or all of colour and if the solvent is miscible with water, water can also be removed or - t7 - partially removed from glycerine liquid. The glycerine liquid may be contacted and mixed with one or more EWA. The EWA may comprise any one or more organic and/or inorganic solvents and/or can be either in single solvent or in solvent mixtures of any mixing proportions with two or more solvents having one or more of the following properties:

(a) immiscible or almost immiscible or very slightly miscible with glycerol, and/or

(b) miscible or partial miscible or immiscible or almost immiscible or very slightly miscible with water, and (c) has significant density difference irom the density of glyccrol-water solution and has significant density difference from water if miscible or partial miscible with water; and/or (d) has significant lower boiling pint than the glycerol-water solution

Examples of such EWA comprise any one or more of the following but not limit to: Acetone, Chloroform, Isoamyl acetate, Benzene, chlorbenzene, Ethyl chloracetatc, ethyl alcohol, n-Heptane, etc and/or any mixtures of such solvents with two or more solvents in any mixing proportion.

If appropriate, the deionisation wastes may be additionally treated. Wastes produced from deionisation processes tends to mainly comprise water and inorganic materials, such as salts. If a large amount of water exists in the deionisation waste, then the water may be separated and rc-used in the glycerine purification processes. Λ Reverse Osmosis (RO) process may be used to rc-claim excess water and is a low cost and a very efficient technology to separate water from organic and inorganic impurities. Water may therefore be re-claimed or rccycled from the waste via a RO process, and reused in the method or to serve other purposes if appropriate. If the impurities removed from the liquid comprise inorganic materials (as can be produced from the purification of crude glycerine produced from bio -diesel and oleo chemical productions), then inorganic materials

5 recovered from the waste may be further processed into commercially valuable products. For example, recovered inorganic materials may be processed into an inorganic fertilizer (Potassium Sulphate, K₃SO₄) or other commercially useful minerals.

Prior to j or during purification and/or deionisation, the glycerine solution l O may be conditioned so as to adjust one or more parameters. The parameters may be selected from one or more of the following: temperature, pressure, pH, hardness, softness and concentration. It is therefore preferably that the liquid is checked and conditioned appropriately so as to ensure that the method is as efficient as possible. If desired, the liquid may be heated prior to (or between) the

15 gravitational separation stage(s), so as to lower the viscosity of the liquid. If the glycerine undergoing purification is required to be (or remains) in a solvent, then after the purification it may be separated by evaporation process if required.

It will be apparent to one skilled in the art that a number of known concentration methods may be employed. For example, the glycerine may be

20 concentrated by means of water evaporation. Evaporation will not only remove water, but other evaporable liquid, such as methanol and other solvents. As water evaporation may be fairly costly, it is preferable that the solution having low glycerine content is concentrated first by removing as much water as possible from the glycerol-water solution before employing a heated evaporation process. Reverse Osmosis (RO) technique may be used initially to concentrate low concentration glycerol-water solution by removing at least some of the water from the solution and such a technique can save a considerable amount of energy when, compared with subjecting the low glycerol content solution directly to a water evaporation process.

If a concentration process is used in accordance with the method, it is preferred that a vacuum evaporator is used to evaporate the exceeding water at much lower temperature than distillation and so as to help in reduction of energy consumption. To avoid possible decomposition of the glycerine during the evaporation process, the process temperature shall be controlled below the temperature which could cause the glycerine to decompose on all the heating surfaces making directly contact with the liquid.

Prior to the one or more gravitational separation stages, the method may include a separation step to initially remove at least some element of MONG₃ including FAEs and some other impurities using one or more floating agents. Such agents have a lower density than the liquid and therefore have a propensity to rise to the surface of the liquid. As these agents rise through the liquid, they carry and/or raise FAEs and other impurities to the surface. These impurities can then be τemovcd from the surface of the liquid by any conventional means known to the skilled person. The one or more floating agent may comprise any one or more of the following: dry or wet air, gas, hollow glass micro-spheres and hollow ceramic micro-spheres, and any other solid or particulates which have lower density than the crude glycerine solution and tend to float or raise to the surface of crude glycerine after settlement over time. The settlement time can either be faster in units of minutes or slower in hours or days. Settlement time can be affected by a number of factors including the temperature and/or viscosity of the liquid irom which glycerine is to be purified. Where the floating agent comprises a gas, the gas may comprise any one or more of the following: air (dry air preferred) and inert gases such as nitrogen and argon etc or non-inert gases such as oxygen and ozone.

^■ The gas will typically be as dissolved gas and form micro-bubbles in the liquid and may be produced by the use of, for example, a liquid-gas/air mixer pump or aeration process (eg. diffusion aerator, dissolved air/gas flotation unit etc.). Hollow or non-hollow micro-spheres with very light density or specific gravity can be used as floating medium by mixing with crude glycerine solution. The micro-spheres tend to float to the surface of crude glycerine by giving efficient time and conditions for settlement. Ideally, such floating separation shall reserve efficient separation or settlement time to allow the best possible separation. The time required for floating process depends on type of floating medium and physical status of the crude glycerine. When circumstances allows, such floating process shall start as early as possible, such as at crude glycerine receiving point in order to have more separation time. The feed stock receiving point can be a unloading point of storage tanks at a glycerine refinery, a crude glycerine outlet point at a biodiescl plant, a loading point of wait-to-ship storage tanks, and even a bulk liquid tanker ship. The floating separation process may only require simple and compact equipment so it is possible to carry out in- sto rage process or in-transit or on-board (of bulk liquid tanker ship) pre-process if other conditions allow. Floating separation should be applied as early as possible in the process to allow more time for separation.

The glycerine may be heated or cooled to a pre-determined temperature prior to or during purification process. The pre-determined temperature of the glycerine will be dependent upon the operational temperature range of the processing equipment, but preferably, the pre-determined temperature is within the range of 30⁰C to 150°C_f except solvent washing process which may require much lower processing temperature in order to avoid the loss of solvent.. The preferred operating temperature ranges of various stages, if present in lhc method of the present invention, are set out below: a) Centrifugal apparatus, up to or over 300 °C, subject to specifications of maximum temperature of apparatus, b) Coalescence devices, up Io or over 250 ⁰C subject to specifications of the best performance temperature and/or maximum temperature of apparatus, c) ED/EDI. Subject to specifications of maximum temperature of apparatus, particularly the best performance temperature and/or maximum temperature of membrane, d) Ion exchange subject to specifications of the best performance temperature and/or maximum temperature of ion exchange resins, e) Polishing: follow specifications of the polishing agents or materials, such as best performance temperature of activated carbons, maximum temperature of de-colour ion exchange resins and/or other agents f) solvent washing. Preferably at room temperature at standard pressure or below room temperature if it is necessary to ensure that the solvent does not evaporate quickly. g) evaporation preferably 20 ⁰C up to 289 ⁰C, more preferably 60 ⁰C to 150 ⁰C, depends on dynamic changes of parts/amount of glycerol in glyccrol-water solution or dynamic changes of volatilities of glycerol- water solution under given vacuum conditions.

More preferably, the pre-determined temperature is within the range of 60⁰C to 150^DC, except solvent washing process. It will be apparent that the crude glycerine may be in a cold or hot/warm format, depending upon how it is supplied. For example, the two conditions when the crude glycerine has been delivered are either: (a) cold, after storage or transportation over a period of time; or (b) hot or warm, if piped in directly out of a biodiesel process or plant. The process may be part of a biodiesel processing plant or alternatively, the process can be carried out in an independent refiner.

Tf on arrival or after storage the crude glycerine is cold, or at a temperature below the lower temperature limit required by a given protocol optimised for the purification of glycerine, then it requires heating. By utilising the remaining heat available from glycerine purification processes such as secondary steam generated from the evaporator and hot glycerine out of concentration process both require cooling, the liquid feed can be heated without the need for, or greatly reducing the requirement of additional energy. The crude liquid is then purified according to the method when it has reached the minimum temperature requirement. In one embodiment, heat contained within the steam from the evaporator can be recovered. The recovered heat may be used to provide heat to warm glycerine in processes. Energy from the water vapour can also be recovered using, for example, heat exchangers. For example, secondary steam (which is evaporated water during product drying process) can be fed into a heat exchanger as heat source, and to be warmed glycerine in process can be fed through the heat exchanger to capture the heat from secondary steam. There may be multi-stage heat recovery heat exchanger, which allows one to maximise the heat recovery. The steam from the evaporator must be cooled down in order to maintain a vacuum. In general, secondary steam may be fed into a cooler and cooled down by a large amount of cooling water.

Alternatively, if the crude glycerine is hot, or its temperature is higher than the upper temperature limit required by a given protocol optimised for the purification of glycerine, then the crude glycerine requires cooling. If the temperature of the hot feed is not much higher than the limit defined in the protocol, the exceeded heat can be used cither to maintain the temperature of the feed in production, or to warm up the cold feed if such heat is needed. If the temperature of the hot feed is much higher than the upper limit of the protocol, the exceeded heat it carries can be used in one or all of following purpose(s): a) as a heat source for a heat exchange device so as to heat up the glycerine in process at earlier or later stage of processes b) to adjust feed concentration:- feeding the hot crude glycerine themselves directly into a vacuum evaporator to remove an initial amount of water. Removing part or the majority of water from the feeds themselves will reduce volume of feed in process hence saving energy in pumping and processing efforts in the production and the concentration of the final product c) as a heat source for material re-covering processes such as purification of FAEs, crystallising salts, or any part of processes requiring heat, or heat source for workshop or the plant heating.

It is preferred that the glycerine is not heated to or close to a temperature exceed required by the process. It is also preferred that the glycerine is heated or cooled by means of heat recovery from within a step in the method. A number of heat recovery means may be employed and these will be apparent to the skilled addressee, for example, the heat recovery may be by means of heat-exchangers, or heat pipes.

The method may also utilise pre-heating as an energy saving measure can offer additional energy saving in the concentration process. Heat exchanges may be used to extract as much heat as possible from other heat recoverable sources prior to a heated water evaporation process. Sources of such heat may be from the initial crude glycerine (if the crude glycerine is supplied to the method already ύi a hot state), a hot final product (after the liquid has been subjected to water evaporation is hot, heating apparatus (such as steam or hot thermal oils), and/or multi-stage heat exchanges in order to maximize the heat recovery and minimize the loss of the heat. The final product may also be cooled down, or partially cooled down by passing its heat to a coolant. If required, the final product may also be subjected to further evaporation process so as to remove the majority or all of the solvent content if there is any. If appropriate, then additional glycerine may be recovered from waste material and residua. By the nature of the method, the re-gencration process of ion exchange resins will result in small amount loss of glycerine. Glycerine recovery may be possible and the method may also incorporate the step of recovering product from waste materials and residua.

In accordance with a further aspect of the present invention, there is provided a method for substantially purifying glycerine from liquids, the method comprising the steps of passing the liquid through one or more gravitational separation stages and a deionisation means. In accordance with a further aspect of the present invention, there is provided a method for substantially purifying glycerine from liquids, the method comprising the steps of passing the liquid through one or more centrifugation stages and a deionisation means.

In accordance with a further aspect of the present invention, there is provided an apparatus for substantially purifying glycerine from liquids, the apparatus comprising AUHGS means located upstream of at least one filtration means.

In accordance with a further aspect of the present invention, there is provided an apparatus for substantially purifying glycerine from liquids, the apparatus comprising AUHGS means located upstream of at least one coalescent filtration means.

Preferably the coalescent filtration means comprises at least one micro- droplet catching matrix. More preferably, the coalescent filtration means comprises a plurality of micro-droplet catching matrices. The matrices may coinprise a filter having a given fibre and pore sizes Preferably, the fibre diameter is from less than 0.5μm to larger than l OOOμm . The fibres are preferably arranged in different layers. More preferably still, the fibres are preferably arranged in layers where successive layers have differing densities of fibres, graduating from very high density to less density such that the glycerine containing fatty acids and esters meets the layer of smallest fibre first then goes through further layers of matrix with larger and larger fibres. The fibres catch droplets of impurities. Finest (smallest diameter) and high density fibres do better catches or vice versa. More preferably, where there are two or more such matrices, the fibre and pore size between successive matrices is different. Preferably the matrices are arranged such that the liquid flows from matrices having smaller fibre and pore size to those having a larger fibre and pore size. More preferably still the fibre and pore size between, successive matrices is graduated. Even more preferably still, the matrix comprises a filter. The filter may comprise a hydrophobic material. The filter may be in the form of an absorbent pad or sheet. The filter may comprise any one or more materials selected from the group comprising: polypropylene fibres, ceramic fibres or ceramic powders, activated carbon fibres etc.

The apparatus will preferably be used to implement the method as herein above described.

Preferably, the apparatus further comprises a deioniscr for substantially removing mono-valent and multi-valent ions from the liquid. The apparatus may further comprise a desalination device for substantially removing salts from the liquid. Additionally, the apparatus may further comprise a conditioning means to adjust one or more parameters of the liquid selected from the following: temperature, pressure, pH, harness, softness and concentration. Tt will he evident that the conditioning means may be more than one device, such as a heater to increase the temperature, or a device for supplying reagent (lor example a pH buffer) to the liquid. A concentration device may also be provided to remove moisture and excess water from the liquid,. Many concentration devices may be employed in the present invention, such as an evaporator or a reverse osmosis filter for example. The apparatus may further comprise a washing means adapted to supply a washing or cleaning fluid to the components of the apparatus if required. Such a washing means may be needed to clean the centrifugal apparatus, coalcscer or various components of the apparatus and are often referred to also as "flush fluids".

The apparatus may further comprise a heating or cooling means for heating or cooling the liquid. It is preferred that the heating and/or cooling means is coupled to a heat exchanger or a heat-pipe system and this will therefore allow the apparatus to operate efficiently and reduce the requirement for external energy to heat the apparatus. The heating means may comprise a heater, boiler, or similar device. A heater may be selected from one or more of the following: a thermal oil heater (using thermal oils as heating media, provides heat at low pressure); a steam boiler (using hot steam as heating media, operating under high pressure); and an electrical heater (producing heat by using electricity). The heating means used will of course largely be dictated by liquid being purified and efficiency requirements etc. In accordance with a further aspect of the present invention, there is provided an apparatus for substantially purifying glycerine solution, the apparatus comprising a AUHGS and GS means located upstream of a deionisation means. In yet another aspect of the present invention, there is provided glycerine purified from a liquid as purified according to the method as herein above described.

A specific embodiment of the present invention will now be described, by way of example only, with reference to the following fϊgure(s) in which: Figure 1 is an overview schematic flow diagram of a possible method of purifying glycerine in accordance with the present invention;

Figure 2 is a schematic flow diagram of a possible method of purifying glycerine in accordance with the present invention;

Figure 3 is a schematic flow diagram of a possible method of purifying glycerine in accordance with the present invention;

Figure 4 is a schematic flow diagram of a possible method of purifying glycerine in accordance with the present invention;

Figure 5 shows a schematic cross-section of a centrifugal apparatus as used in the method of the present invention; and Figure 6 shows a schematic diagram of an indicative illustrating coalescence process as being used in the method of the present invention.

With reference to Fig. 1_} there is provided an overview schematic flow diagram illustrating the purification of glycerine from a crude glycerine source. Tlic key stages of the process illustrated in Figure 1 can be summarised as follows:

.The key to the Fig. 1 is as follows: (G). Feed Stock; (1). Pre-process:- to remove solid impurities and part of MONG,

Crude glycerine liquid can be conditioned if required;

(2) MONG removal or Organic impurity removal processes. Vast majority of MONG including FAEs are removed in this process with number of different mechanisms and methods including AUHGS, Coalescent, Floating and SEWP processes followed by an optional MONG fine removal process which is able to produce much cleaner glycerine liquid to meet production requirement and/or product specifications.

(3) salts removal or deionisation and de-colourisation processes;

(4) polishing and extra fine purification (5) Concentration.

(6) Materials recoveries, re-cycle, water treatment and wastes process;

Pl -P4 glycerine product in varying grades of purity

P5-P6 materials reclaimed from crude glycerine during purification process. At various stages glycerine can be produced in varying grades of purity:

A, B, C, D, E and F of technical grade glycerine and Food and/or Pharmaceutical

(Food/Pharma) grade glycerine, with Food/Pharma glycerine and technical grade

Λ being the most pure and grade F the least pure. The feed stock or crude glycerine comprises glycerine and any one or more of the following: organic impurities, inorganic impurities, biological impurities and water. Typical biodiesel crude glycerine contains 80% or higher glycerol content and rest impurities. Impurities contained in biodiesel crude glycerine may fall into following categories:

(a) inorganic impurities: include salts, minerals and heavy metals;

(b) MONG: includes fatty acids, esters (mono-/di-/triglycerides), methanol, proteins, gelatines, gums, pesticide, herbicides, fertilizers, toxic or non-toxic metabolizing wastes of micro-organisms, such as from bacteria, moulds and yeasts/microzymes, etc any other organic materials presenting in vegetable oils, tallow and/or used cooking oils which are stored over period of time;

(c) biological impurities: such as bacteria, moulds, yeasts/microzymes and even virus, and (d) water.

For feed stock derived from used cooking oils (UCO), there are other impurities, such as sugar, food ingredients and flavouring agents. With reference to Figure 2, there is provided a schematic flow diagram illustrating the purification of glycerine from a crude glycerine source. The key stages of the process illustrated in Figure 2 can be summarised as follows:

(1) Pre-process, include general filtrations and/or general absorptions, gravimetric floating separation and conditioning;

(2) MONG removal, (3) de-salinization/de-ionisation,

(4) polishing processes, including SEWP to clear out any remaining MONG

(5) Materials recoveries, water treatment and wastes process; (6) Concentration and heat recovery

Glycerine purification process preferably starts from the Pre-process stage. In pre-process, general filtration can be used to remove particles with sizes from as small as 1 μm to larger and/or very large pieces objects and to remove some or quite majority of MONG from crude glycerine liquid. General filtration means the use of many types of filtration methods include but not limited to filtration mesh made of/from any materials with any number of mesh counts; earth materials large or small in size, such as sands, coals, carpolites, lava stones or lava rocks, any types of stones, slales and rocks, etc. being in layered or mixed formations in any order with any proportion and/or layer thickness in layered; and/or use of any type of fillings and/or accumulations of any solid materials or objects in any sizes and shapes with any amount/quantity and/or in forms of natural or processed/made and/or in broken or un-broken forms and/or in loose, shaped or formed forms or being in layered and/or mixed formations or structures in any orders, such as timber and/or timber pieces, barks, rinds, leaves, chaffs, straws, corn-cobs, charcoals, tree branches, coals^ pieces bricks, ceramics, glasses, concretes, plastics, rubber, shells, lava stone/rocks, etc.

Pre-process can also apply floating process. Floating process separates MONG from crude glycerine liquid and it can be carried out either on-site or off- site. The floating process preferably starts as early as possible for example to start from the very first receiving point of crude glycerine such as during manufacturers' wait-for-ship storage tanks and/or in long distance transportation and/or at the glycerine refinery's on-site receiving tanks. Many floating means can be used as flo citing media for example but not limit to dry or wet air or inert gases are convenient floating materials for off-site floating process.

There are four organic impurities stripping processing methods to remove MONG. 203 is primary or first line MONG removal process comprising AUHGS process, Coalescent process, Floating process and SEWP as illustrated by 203A, 203B, 203 C and 203D in Figure 3. After MONG removal processes 203, there is an additional and optional MONO fine stripping process which offers an option to further remove MONG by fine coalescent filtration followed by an optional fine absorption process which can strip FAEs down to extremely low level with higher production costs and more production wastes. SEWP is an option to replace the fine coalescent filtration and fine absorption processes. SEWP can further wash out remaining MONG and further clean up the glycerine liquid including remove some of or most of colours depending on quantity of EWA being used and number of SEWP being carried out, in general the more quantity of EWA and more number of SEWP are applied, less MONG left or much cleaner glycerine solution. Water in glycerine liquid can be reduced by SEWP if water miscible solvent presents in the EWA.

The key to the Fig, 2 is as follows:

101. Feed stock;

102. Pre-process:- to remove dirt and part of organic impurities; 201. Control point to send crude glycerine Teed being heated or not heated.

202. Pre-heat;

203. Primary MONG removal process comprising four processing methods or elements in parallel as shown in Fig. 2 and Fig 3, they arc:

203A. accelerated ultra-high G-force centrifiigation (AUHGS) 203 B. coalcsccnt filtration, 203 C. floating separation, and

203D. solvent extraction and washing process (SEWP); By receiving heated feed from 202, there are three heated primary processing routes in 203 marked as A₅ B and C in Fig. 2 and 203A, 203B and 203C in Fig 3). The three heated processing routes apply different separation methods or working concepts in parallel or in conjunction or combined manners to remove MONG from heated crude glycerine in low viscosity and there is additional parallel primary SEWP route, marked as D in Fig. 2 and 203D in Fig 3, works with either heated or non-heated crude glycerine preferably non-heated or under room temperature. AU of four methods in primary MONG removal processes 203 can work independently and/or work in conjunction or combination with one or more than one of others and each has following characteristics: 203 A: an AUHGS process, applying accelerated ultra-high G-force onto crude glycerine liquid and non-sclectively separating all of MONG from glycerine liquid and preferably works with low liquid viscosity such as heated crude glycerine. 203B: a Coalescence process. Preferably works with heated glycerine liquid in low liquid viscosity. Coalescence process coalesces suspended, dispersed or emulsified micro -droplets of FAEs in glycerine liquid body into large drops and utilising gravitational separation force in a mixed liquid system containing two immiscible liquids having significant density differences. Having being coalesced into large drops, FAEs gain enough rising force due to their significant lower density than that of glycerine solution and rise to the top of the liquid and FAEs are separated from glycerine solution. Coalescence process is basically a selective process which selectively removes FAEs, but it may also have some effects on low density organic impurities or small and low density particles by carrying them to the top of liquid with the rising drops of FAEs.

203 C: a Floating process. Preferably works with heated feed with lower liquid viscosity. Floating process uses very small bubbles of air and/or gases preferably inert gases or other types of low density solid and small or large light objects as floating agent to carry micro-droplets of FAEs and low density small organic particles to the top of glycerine liquid. Preferably uses air and/or gases as floating agent. More preferably uses dry air, or dry inert gases or weak or mild oxidising gases as floating agent. Heated glycerine liquid in low viscosity will reduce processing time significantly and having higher processing efficiency. Some small organic materials and small particles which have lower density than glycerine liquid may also be driven to the top of liquid by floating agents.

203D; SEWP, may receive heated feed from 202 or receives un-heated and/or warm feed from 201 in room temperature such as 20 - 35°C. More preferably works with the feed in room temperature. SEWP removes all of organic impurities, including some of colours and odours, and water can be partially removed if the EWA presents with quantity of water miscible solvent. EWA left in glycerine liquid shall be removed at later stages by suitable means.

Any one of the four processes described ill 2003A₃ 203B, 203C and 203D can be carried out independently giving rise to product having different purity and factors to be considered in any suitable application will be: cost of apparatus and/or materials and/or production, production time or production efficiency and process simplicity and .or complexity. Selection of which process to be used/applied depends on number of factors such as quality of crude glycerine, product requirement or product specifications and/or requirement or limit of the apparatus for next processing stages, etc. In some circumstances it maybe necessary to install apparatus for all of four processes. The number of processes to be applied in a glycerine refining and/or production plant and/or how many apparatus to be installed will depend on actually purpose of the glycerine refinery, and range of glycerine products. Any one or more of the four processes can be applied in a glycerine refinery.

ATJHGS process (203A, Fig. 3) either receives heated or warmed up feed from 202 or teed at lower temperature from 102, higher feed temperature greatly improves separation efficiency than un-heated feed or feed at room temperature because the viscosity of glycerine liquid will be great reduced in higher liquid temperature. AUHGS applies ultra-high speed centrifugal force on feed liquid. Organic impurities are separated from glycerine because glycerine gains much greater separation force due to significant density difference from that of organic impurities. AUHGS process also clears solid particles from the liquid. Coalescent filtration process (203B, Fig. 3) receives heated feed from 202 and performs FAEs stripping process by utilising density differences of two immiscible liquid phases: glycerol-watcr phase and FAEs phase, to separate FAEs which are in either suspended, dispersed or emulsified state or all of the states from the main liquid body of glycerol-watcr solution. A Coalesccr comprises a number of filtering layers in series having a graduated micro-droplets capturing fibre sizes. The capturing fibres capture micro-droplets of FAEs in the liquid and allow micro-droplets to collide into each other and form larger drops hence to gain efficient gravitational force from their density and size and rise to top of the glycerine liquid and achieving separation.

Floating process (203 C, Fig 3) uses very small bubbles of air and/or gases preferably inert gases or other types of low density solid and small and large light objects as floating agent to carry micro -droplets of FAEs and small and light organic particles to top of glycerine liquid. Dry air and/or dry inert gases or weak or mild oxidising gases are preferably used as a floating agent. Small bubbles can be produced and introduced into glycerine liquid continuously or in predetermined intervals by a number of means widely used in industry with a predetermined Gas to Glycerine mixing ratio for a given length of running and settling time. Heated glycerine liquid with significant lower viscosity help to reduce processing time and having higher processing efficiency. Together with FAEs droplets, floating agent may also cany some of small and low density particles to the top of glycerine liquid.

Solvent extraction and washing process (SEWP, 203D in Fig. 3) receives heated feed from 202 or receives un-heated and/or warm feed from 102. Preferably SEWP works at lower temperature or room temperature such as 20 - 35⁰C. More preferably SEWP works in room temperature between 25 - 30⁰C. SEWP employs solvents to extract and wash out organic impurities. SEWP is a non- selective process. SEWP will remove all of organic impurities, therefore EWA process can replace both AUHGS process and Coalescent filtration process to separate MONG by means of solvent washing. In SEWP, crude glycerine feed should be at lower temperatirre which reduces the loss of EWA. EWA process may partially or almost dc-colour the crude glycerine depending on number of washes. If there is a significant quantity of water misciblc solvent present in the EWA solutions which will depend on total quantity of water rniscible solutions presented and number of EWA processes, the water content in the crude glycerine can be reduced or even almost completely removed together with the removal of organic impurities. The EWA process can remove water from glycerine liquid without a heating pre-step, hence save energy and cost. Any one or more of the four primary MONG stripping processes can be used depending upon the quality of feed crude glycerine, product requirement and/or product specifications, costs of productions, production conditions, environment, waste and many other issues. All of the four primary MONG removal methods of 203A, 203B, 203C and 203D can either work independently. All of the four primary MONG removal methods can also work in conjunction or combination with one or more than one of the others, such as: (a) glycerine feed to 203 A and/or 2O3B is a mixture of crude glycerine liquid and floating agents such as air/gas bubbles, rather than just the crude glyceriiic liquid itself. This will result much higher separation efficiency. Preferably not use solid floating agent in 203B, or (b) glycerine feed to 203 A or 2O3B is a mixture of crude glycerine liquid and

EWA, giving much higher separation efficiency, or ■ (^c) glycerine feed to 203A is the glycerine liquid after or having undergone processes of cither 203B, 203 C and/or 203D above.

204. Control point between process;

205. MONG fine stripping process, an optional fine process which further removes MONG and/or FAEs from process outlets of 203. It further reduces MONG content particularly FAEs content down to extremely low level. There are typically three means of the MONG fine stripping processes:

(a) fine coalescent filtration process - gives very low FAEs content.

(b) absorption process - gives extremely low FAEs. It employs specific absorbents to clean out remaining FAEs and reduce FAEs content in glycerine down Io <l-2 ppm or lower. There are wide range of available absorption materials in various forms such as pads, sheets and/or in many other forms made of polypropylene fibres, ceramic fibres or powders, activated carbon fibres etc.

(c) SEWP - fine SEWP gives extremely low MONG content. It employs EWA to wash out remaining MONG and further reduce MONG content in glycerine solution. The cleanness of glycerine solution depends on quantity of EWA being used and number of process being carried out. Some water and colour can also be removed by the fine SEWP. ^rPhe three fine processes can cither work independently or to be combined in any processing sequences or in any working orders. If FAEs are the major concern of product quality or for production efficiency, both coalescent filtration and absorption processes can be used as they selectively remove FAEs. SEWP is a non-selective process and it removes organic imparities including FAEs as whole. In addition, SEWP also removes colours and some of odours if exits. Water content of glycerine liquid can be reduced if the EWA contains quantity of water misciblc solvents. 301. Control point - to determine product quality, further de-salt or not de-salt. If no fiirther de-salt, collects technical grade D to F products (Pl) with high salt content, in lighter colour if has gone through SEWP in MONG removal processes or in dark colour if did not go through SEWP in earlier process..

302. Desalination and dc-lonisatioπ process. Desalination process deals with high salinity liquid by using electro-dialysis process. Deionisation process deals with liquid with lower salinity by using either EDI or ion exchange reins.

Depends on level of salinity and product specifications, de-salinization process can be carried out as an individual process with one of the means or as combined processes. ED₇ EDI and ion exchange can be combined in any processing sequences or in any orders, but ideal processing sequence shall be in such manner to process crude glycerine with high salt content: (a) ED (electro-Dialysis), (b)

EDI - clectro-deionisation, and (c) ion Exchange resins. ED/EDI can produce satisfactory low salt products for general industrial uses. Ion exchange resin is able to remove salts down to extremely low level, <1 ppm is achievable if required.

303 de-salinization and de-ionisation QC control point

401. Contro 1 points between process, whether to carry out polishing process; if no further polishing, collects technical grade C products (P2) with

MONG and salts removed, in lighter colour if has gone through SEW? or in darker colour if no SEWP applied.

402. Polishing means de-colour, dc-odour and/or further fine treatment etc in general (a) De-colour - by, for example, activated carbon or de-colouring resins, SEWP and (b) De-odour - by, for example, activated carbons or other odour absorption agents and SEWP. Some or all of odour may be removed if has gone through SEWP in earlier processes. Preferably de-odour is not carried out by the use of hot steam because it introduces water and/or large amount of water into glycerine. 403. Control point between process; determine to stay with technical grade or go for higher grade of food/pharma grade product.

404. Further extreme pure process - preferably applies one or more SEWP with clean or fresh EWA to wash out any possible remaining organic impurities and achieve the highest purity or food/pharmaceutical grade glycerinc- water solution. Colour and odours are completely removed at this stage, water content can be further lowered if quantity of water miscible solvents presents in the EWA. Used EWA from this process can be directly used as source EWA in earlier stages of MONG removal processes such as in 203 and/or 205. The EWA can comprise any one or more organic and/or inorganic solvents and/or can be either in form of single solvent or in form of solvents mixtures in any mixing proportions with two or more solvents having one or more of the following properties:

(b) misciblc or partially miscible or immiscible or almost immiscible or very slightly miscible with water, and

(c) has significant density difference from the density of glycerol- water solution and has significant density difference from water if miscible or partial miscible with water; and/or

(d) has significant lower boiling pint than the glycerol-water solution about to be washed

Examples include but not limit to Acetone, Chloroform, Isoamyl acetate,

Benzene, chlorbenzene, Ethyl chloracetate, ethyl alcohol, n-Heptane, etc and/or any mixtures of such solvents with two or more solvents in any mixing proportions

Clean EWA are fed in from EWA recycle process 601;

501. Control point - to switch between product concentration process and non-concentration; if no further concentration required, collects products (P3) which meet product specifications except water content at this point, such as

Technical grade B and/or Food/Pharma grade B glycerine with glycerol content

>80%. 502. Heat recovery, the main heat recovery system to recover heat from the secondary steam generated by concentration or water evaporation process and to use the heat containing in the secondary steam to heat up the product which is to be concentrated; 503. Product pre-heat, utilises the remaining heat from primary heat source (hot thermal oil or hot steam or any other type of primary heat sources) comes out of evaporation vessel after providing heat to evaporation;

504 Vacuum evaporation unit., to concentrate glycerine up to specified concentration up to or higher than 99.7% of glycerol by remove exceed water and solvent out of the glycerine, if there is requirement, glycerine liquid being or not being dc-salted, being or not being polished can undergo concentration process and produce highly concentrated technical grade glycerine with or without higher salt content and/or with colour. Products has gone through SEWP shall undergo evaporation process or other suitable or applicable solvent removal means to have exceed solvent completely removed, and such product may have much lighter colour and/or less or no odour.

505 heat recovery, recovers heat containing in final product P4

506 Secondary steam, the steam produced from product concentration process. Secondary steam is fed into a heat recovery system for the purpose of utilising the heat to warm /heat up glycerine feed in process;

507 Heat source, a steam boiler or an electric powered thermal oil heater. Provides heat to concentration and product pre-heat process.

601 Glycerine recovery and FAEs separation and EWA recycle process. MONG comes out of 203 contains majority of MONG and small quantity of glycerine. Glycerine is separated from rejected MONG, returned to 202 and undergoes further processes. Used EWA comes out of 203 contains large amount of EWA with or without water, MONG and small quantity of glycerol, EWA is recycled and returned to processes of 404 or 205 or 203 C (Fig. 3). FAEs from 203 and EWA recycle process 601 are collected and further processed to remove other organic impurities, cleaned and dried and finally re-claim clean and dry FAEs P5;

602. Water treatment plant - a RO (Reverse Osmosis) system to recover water and produce de-ionised water for re-use. Recovered de-ionised water is returned back to ED/EDI and ion exchange process, most of wastewater are recycled.

603 Wastes process — treatment of solid and liquid wastes, to recover remaining feed stock and all possible re-claimable materials, including methanol;

Pl - Pό. Final products and re-claimed materials - either un- concentrated or concentrated in various grades depending at which stage of the process it is collected;

P7 Final wastes, mostly organic materials except glycerol and FAEs, and/or highly concentration salt water if any.

Vc shown as a upwards arrow on top of each process handling heated glycerine. All link together, they form a methanol collection system, collecting methanol vapour, lead to a chillier and turn methanol vapour into liquid methanol.

In use, the process is conducted in the following manner. Firstly, the feed stock 101 (comprising a liquid containing glycerine and impurities) undergoes pre-process 102 for clearing up dirt, such as solid impurities, small and large size solids, removing part or significant amount of FAEs and conditioning the feed crude glycerine (to control the pH, hardness, softness etc.) if required. The feed crude glycerine then enters a heat exchanger to heat up with remaining heat from the secondary steam or from primary heat source if required making the feed crude glycerine to a temperature and low viscosity required for next process, or feed crude glycerine comes out of 102 enters EWA process in 203 (203D, Fig 3) without being heated. Often, except undergoing SEWP, the temperature of the feed stock will need to be increased in order to allow the liquid having a lower viscosity and to flow more easily. The feed crude glycerine then enters the main process 2 starling from stripping of organic impurities or MONG removal processes. The removal of MONG is by means of an AUHGS or ultra-high speed centrifugation and/or SEWP or solvent extraction and washing process, both are non-selective MONG removal process. IfFAEs is the only and/or major concern, then in stead of applying AUHGS or SEWP, FAEs stripping processes (coalescent process and/or floating process as 203B and 2Q3C, Fig. 3) can be used which operates at ordinary gravitational separation without using expensive equipment or solvent. SEWP uses solvent extraction and washing mechanism to remove MONG and it can be an alternative MONG stripping process to replace AUHGS process. After MONG removal process 203, if there is still requirement for lower MONG and/or FAEs, there is an optional MONG fine stripping process (205) which employs either very fine coalescence process and/or FAEs absorption process, either can work independently or combined at any sequences preferably coalescence followed by absorption. Instead, MONG fine stripping process 205 can employ SEWP alone to strip MONG as well as FΛEs down to very low level. The MONG fine stripping process can be by-passed if there is no such requirement for very low MONG and/or FAEs content. If SEWP are carried out in 203 or 205, some of colours and odour can be also removed, and water can also be partially removed if water misciblc solvent were used. Light phase output of the AUHGS process is collected, remaining glycerine is separated and fed back to the starting point of MONG removal process; used EWA is collected, recycled and clean EWA returned back to glycerine purification processes, FAEs separated form the EWA recycle and MONG separation processes are reclaimed (P5) after further cleaning and/or treatment. If there is no requirement to remove salts, colour and higher concentration of product, low-end products are obtained (Technical grade D and F) at this point and if required products collected at this point can be further concentrated.

The glycerine then undergoes desalination and deionisation process (302) to remove salts. It produces de-salted and/or de-ionised glycerine. Wastewater is pumped to water treatment and recovery plant (602) of the materials recovery and waste treatment system (6). Recovered de-ionised water produced from water treatment plant (602) returns to desalination and deionisation process (302) and water is re-cycled.

The glycerine then passes through a quality control point 303 to check that the glycerine has the correct salt content. If QC failed, glycerine is returned back to the desalination and decolourisation 302 stage and/or may either repeats ED/EDI process or may directly go through ion exchange system for extremely fine de-ionisation process. If QC passed, it is then passed to a further control point (401) to assess whether it requires polishing. In general, polishing means de-colour, de-odour, further fine treatment etc. (a) De-colour - by activated carbon or de-colouring resins, and (b) De-odour - by activated carbons or other odour absorption agents. EWA process is able to remove colour and odour and it may require repeated EWA process to remove colour or odour completely. If extremely pure glycerine is required, such as top of technical grade and/or food/pharma grade glycerine, the control point 403 will divert the glycerine through EWA process which uses extraction and washing agent (EWA) to extract and wash out any possible remaining MONG with EWA comprises of but not limit to Acetone, Chloroform, Isoamyl acetate, Benzene, chlorbenzene, Ethyl chloracetate, ethyl alcohol, n-Heplane, etc. The EWA can be any organic and inorganic solvents and/or can be either in single solvent or in solvents mixtures of any mixing proportions with two or more solvents having one or more of the following properties: a) immiscible or almost immiscible or very slightly miscible with glycerol, and/or b) miscible or partially miscible or immiscible or almost immiscible of very slightly miscible with water, and c) has significant density difference from the density of glycerol-water solution and has significant density difference from water if miscible or partial miscible with water, and/or d) has significant lower boiling pint than that of the glycerol-water solution.

If no concentration is required, the glycerine is in the form of the filial product P3 with glycerine content as is. In most cases, concentration is required. Glycerine is firstly passed through heat recovery system, so as to recover the heat from secondary steam generated by evaporation process and is heated up by the heat of secondary steam The warmed up glycerine then gains higher temperature by passing through pre-heat device (503), which utilises the remaining heat left in the primary heat source coming out of the evaporator. The glycerine then passes through a vacuum evaporator 504 which uses primary heat from any type of heat sources, steam, hot thermal oil, direct electric heating, etc. to dehydrate the product and bring it to the correct concentration and in the form of the final product (P4). If required, a primary heat source can be used to supply heat for the evaporation as well as to the pre-heat heat exchanger. Secondary steam which comes out of evaporator can be fed into the pre-heat system as well as to other heat recovery devices, to heat or warm up crude feed or feed in process.

In respect of the materials recovery and waste treatment process 6, waste from EWA recycle and glycerine/MONG separation 601 and water treatment system 602 can undergo a further wastes process treatment 603 for the treatment of solid and liquid wastes, so as to recover remaining feed stock, if there is any, and possible re-claimablc materials, including but not limit to methanol. Reclaimed materials, such as organic and inorganic by-products can be collected, Reclaimed water from the water treatment system can also be a reclaimed material. The grading technical grade glycerine into A, B, C, D, E & F, with A presenting the best and F the poorest, is intend to reflect quality differences. Food/Pharma grade glycerine is the most pure glycerine. Technical grade A presents a class of technical glycerine in water white with >99.5% of glycerol content; Technical grade F represents a class of technical glycerine having highest organic and inorganic impurities, with colour and higher water content. Grade C, B, D and E are in between grade A and grade F, depending on contents of fatty acids, salts, colour and water.

With reference to Figure. 3, it illustrates four of primary MONG removal processes in parallel with different processing mechanisms or purification concepts. 203A undergoes an AUHGS process that applies ultra-high separation forces on the liquid and effects all of MONG; 203B applies coalescent mechanism and makes micro-droplet of FAEs become large drops and raise to the top of liquid due to significant density difference of the immiscible liquids; 203C is a floating process which applies bubbles of air and gases to help clear up of small particles and micro-droplets of FAEs by carrying them to the top of glycerine solution and 203D is a solvent extraction and washing process (SEWP) that employs EWA to wash out MONG including colours, odour and possible some water content. With reference to Fig. 4, there is provided a schematic flow diagram illustrating the purification of glycerine from a crude glycerine source.

The key stages of the process illustrated in Figure 4 can be summarised as follows:

(a) Pre-process; (b) Organic impurity removal, and fatty acids separation - AUHGS centrifugation + coalescence processes, same as described in Fig. 2 and Fig. 3

(c) Fine filtration - ultra- and/or nano-filtrations, to achieve the higher product purity; (d) De-Stalinisation, de-ionisation and de-colouring processcs_? same as the previous; and

(e) Diying and heat recovery. Heat containing in the steam from drying process is recovered via two steps - heat recover devices A and B. The key to the Fig. 4 is as follows:

01. Feed stock;

02. Pre-process:- general filtration to remove dirt and part of MONG, same as describes in Fig 2 and feed stock conditioning;

03. Main process; 04. Heat recoveries - methanol and any vaporisable gas when being heated arc also collected in heat recovery processes;

05. Materials recoveries, water treatment and wastes process;

06. Heating of feed stock, and Heat Recovery 2, to recover heat in secondary steam from dryer; 07. Organic impurity removal and fatty acids stripping processes - by

(1) ultra-high speed centrifugation to remove MONG, including almost all of FAEs, and (2) using coalescence process to further remove any remaining FAEs, down to very low level. Step (2) can be by-passed if there is no demand for extremely low fatty acids content; 08. Separate FAEs from other organic impurities, collect FAEs, and reclaim feed stocks;

09. Control point between process; 10. Ultra- and/or naiio-filtrations. Further removing remaining tiny amount of MONG, for extremely pure products; This stage can be by-passed if there is no demand for higher purity.

11. MONG and feed stock separation, to recover feed stock; 12. Desalination and de-colourisation processes;

13. Water treatment plant - to recover water and produce de-ionised water required by process (12);

14. Control point - to check salt content;

15. Control point - to switch between non-evaporation (no drying) process and evaporation (drying) process;

16. Heat recovery 1, to recover the heat from secondary steam generated by drying process, use the heat containing in secondary steam to heat up the product which to be dried;

17. Product pre-heat, utilises the remaining heat left in primary heat source (hot thermal oils or steam or any other type of primary heat sources) comes out of drying vessel;

18. Evaporator, Uses primary heat from any type of heat sources, steam, hot thermal oils, etc. to dehydrate the product and bring it to a very high concentration. Heat in secondary steam produced from evaporation process will be recovered. Heat in product will also recovered;

19. Final products - either un-concentrated, or concentrated, at various grade, depending processes involved and product specifications;

20. Heat source. This is the primary heat source to supply heat for the evaporation process; 21. Secondary steam comes out of the evaporator. Heat contains in this secondary steam will he recovered by heat recovery device A;

22. Secondary steam comes out of the evaporator and being cooled once. Heat value in this steam is much lower now, but there is still recoverable heat;

23. Wastes process - treatment of solid and liquid wastes, to recover remaining feed stock and possible re-claimable materials, including but not limit to methanol;

24. Rc-claimed materials; and 25. Final wastes - to be disposed.

In use, the process is conducted in the following manner. Firstly, the feed stock 01 (comprising a liquid containing glycerine and impurities) undergoes pre- process 02 for conditioning (to control the pH, hardness, softness etc.) and micro- filtration or general filtration 02 (to remove dirt and surfaced FAEs). The stock then enters a heat recovery system B 06, in order to heat the stock to the correct temperature for fiirther processing. Often, the temperature of the stock will need to be increased in order to allow the liquid to reduce its viscosity and to flow more easily. The stock then enters the main process 03 and organic impurities, including FAEs are removed by MONG stripping processes (centrifugation + fatty acids removal) 07. The removal of all organic impurities (including almost all of fatty acids) is by means of AUHGS oτ ultra-high G-force centrifugal separation to remove organic impurities, and by using coalescence process to further reduce the remaining FAEs down to very low level. The coalescence process can be bypassed if there is no demand for a glycerine having an extremely low FAEs content. Tf desired, FAEs can ^"be separated 08 from other organic impurities, collected, and feed stocks reclaimed 11 under the waste recovery process 05. Low-end product can be collected after MONG removal process 07, and the product characterises low FAEs but having high salt content, colour and water. If extra pure glycerine is required, the control point 09 will divert the glycerine through ultra/nano-filtralion 10. The resulting Tesidua can be fed into the material separation and recovery system 1 1 of the waste recovery process 05. The ultra/nano-filtration 10 is used to remove further remaining organic impurities having very large molecular weights or very high Daltons, for higher product purity. Dilution of feed glycerine solution is required in order to allow the glycerol across ultra/nano-filtration membranes at reasonable flux rate. The glycerine then undergoes desalination and decolourisation 12, From the desalination and decolourisation 12 stage, wastewater is passed to the water treatment system 13 in the waste recovery process 05. Recovered de- ionised water ftom the water treatment system 13 is then passed back to the desalination and decolourisation 12 stage hence water is rc-cycled.

The glycerine then passes through a control point 14 to check that the glycerine has the correct salt content. If the salt content of the glycerine is failed quality control, it is returned back to the desalination and decolourisation 12 stage until passes quality control. If the salt content of the glycerine is OK, it is then passed to a further control point 15 to assess whether it requires concentration. If no concentration is required, the glycerine is in the form of the final product, a lower grade glycerine product at lower concentration with low fatty acids and low salt in light colour or water-white and very clear liquid. In cases of higher or highest product concentration is required, the glycerine is passed to a heat recovery system A 16_} so as to recover the heat from secondary steam generated by evaporation process and using the heat containing in secondary steam to heat up the glycerine which to be concentrated. The glycerine is then passed to a pre- heat system 17, which utilises the heat left in primary heat source (hot thermal oils or primary steam or any other type of primary heat sources) which comes out of evaporation vessel after providing heat for evaporation process. The glycerine then has much higher temperature and passes through a vacuum evaporator 18 which uses primary heat from any type of heat sources, steam, hot thermal oils, etc. to dehydrate the product and bring it to the correct concentration and in the form of the final product 19. Tf required, a primary heat source 20 can be used to supply heat for the evaporation and as well as for the pre-heat system 17 as it still contains a lot of heat when flows out of evaporator. Secondary steam which comes out of the evaporator 18 can be fed through 21 into the heat recovery device A 16, and further feed into heat recovery device B 06. The heat value in this secondary steam 22 is much lower, but the remaining heat still be recoverable. Finally the secondary steam is sent to a cooler and turned into liquid in order to maintain system vacuum. Heat in secondary steam can be used to heat up other materials if required, or if there is no requirement for heat recovery, the secondary steam can be directly cooled down by a cooler.

In respect of the waste recovery process 05, waste from materials separation and recovery 11 and water treatment system 13 can undergo a iurther wastes process treatment 13 for the treatment of solid and liquid wastes, so as to recover remaining feed stock and possible rc-claimable materials, including but not limit to methanol. Reclaimed materials 24, such as organic and inorganic byproducts can be removed. Reclaimed water from the water treatment 13 system can also be a reclaimed material 24. Any material which can not be recovered will exit the process as waste 25.

With reference to Figure 5, there is illustrated a tubular shaped centrifugal apparatus 700 which can be used in the MONG removal process 203 of Figure 2 or 203A of Figure 3 and the centrifugation step 07 of Figure 4. The centrifugal apparatus 700 has a liquid container body 702 having a generally upright cylindrical shape, inside which liquid is displaced and accelerated at extremely very high speed around a central longitudinal axis 704 in a given direction (indicated clockwise by arrow 706) clockwise or counter-clockwise depends on actual device designs The liquid container body has a base 708, 710 indicates bottom feed of glycerine liquid preferable central feed inlet but the feed can be edge- feed (through bottom of side wall or bottom-edge of liquid container body) or the feed can enter the liquid container 702 through feed inlet points located at any suitable location on the base of container, through which, the liquid to be purified 712 can flow in. Towards the top of the liquid container body 702, the centrifugal apparatus 700 has two outlets. The first outlet 714 comprises a central collection point 716 which is the outlet of light -phase liquid 718 which is pushed inwardly towards centre of along central longitudinal axis 704 of interior liquid body (not necessary a physical object) forming a central portion of light phase liquid. Outlet 714 channels light phase liquid 718 through light phase liquid collection point 716 positioned in the centre and interior of the liquid container to extemal outlet point 720 of the centrifugal apparatus. The second outlet 722 is arranged to collect material or heavy phase liquid in the outer portion 726 of the interior of the liquid container and heavy phase liquid is discharged from a centrifugal apparatus. Heavy phase liquid collection points can also be arranged on side wall at the top of the container body or top side- wall outlet or collection point. The material in the outer portion 726 will be heavy phase liquid 724.

During operation, the centrifugal apparatus will accelerate the liquid and make the liquid rotate about the axis 704 at a pre-determined speed or CSF, as will be discussed later. Crude liquid glycerine 712 is fed into the interior of the centrifugal apparatus through any bottom feed inlet point (indicated by 710) at its base 708. The rotation of the liquid at ultra-high speed inside 702 results in the accelerated ultra-high gravimetric separation force or CSF to separate heavy and light phases of the liquid. The heavy phase is forced outwardly towards the outer portion of 726 or towards the inner wall, whilst the light phase remains in the central portion 718 of the interior liquid body. As there is a continuous flow of crude glycerine into the aperture 710, the light phase 718 is forced out of the light phase outlet 714, whereas the heavy phase 724 is forced out of the heavy phase outlet 722. Over time, solids 728 may accumulate towards the base of the inner wall of the liquid container body 702. If required, these solids can be removed by automated washing steps or simply stopping the centrifugal apparatus and manually and physically removing the solids.

Whilst only one centrifugal apparatus body is shown in Figure 5_? the method of the invention may employ a number of such centrifugal apparatus connected in series for higher liquid quality or connected in parallel for higher processing quantity. These centrifugal apparatus may make the liquid displaced at different speeds resulting/having different CSF or at the same speed with the same CSF. Such centrifugal apparatus are able to generate AUHGS force. Multiple centrifugal apparatus connected in parallel or group of parallel centrifugal apparatus multiples the processing power and process larger quantity of crude glycerine feed. By linking number of such group in series in two or more tiers will achieve both higher processing quantity and higher quality. Such parallel grouped apparatus linked in series at two or more tiers can be a solution for large glycerine refineries. The provision of multiple centrifugal apparatus allows for a higher purity of the glycerine from the heavy phase outlets.

The AUHGS stage can involve accelerating the liquid to speeds gaining/obtaining CSFs in the range of 5,000 to 50,000 or higher. The AJHGS stage can involve accelerating the liquid to different speeds with different CSFs. For example, the AUHGS stage may have a first step of accelerating the liquid to a speed having 5,000 CSF, a second step of accelerating the liquid to 10,000 CSF and a third step of accelerating the liquid to 30,000 CSF. The discrete steps will preferably be applied to the liquid sequentially. The differing speeds may be applied to a single centrifugal apparatus, or undertaken in different centrifugal apparatus. Alternatively, the centrifugal apparatus may simply operate at an optimised speed and/or the maximum speed.

The AUHGS force is applied to the crude glycerine feed by using ultrahigh speed centrifugation. Organic impurities (denoted as MONG in Figure 5 - materials organic noii-glycerol) will be separated as a mixture of light phase liquid from the heavy phase liquid (crude glycerine), and discharged form light phase outlet 714. Cleaner crude glycerine will he discharged from the heavy phase outlet 722.

One or more than one such ultra-high speed centrifugal apparatus can be linked together in series and to purify the glycerine by one or more than one steps of AUHGS. More than one such ultra-high speed centrifugal apparatus linked together in series can be further arranged in parallel sets in order to process larger volume of crude glycerine simultaneously. In order to achieve higher processing efficiency, the feed crude glycerine can be heated to reduce this viscosity of the liquid. When the liquid is at lower viscosity, the separation of the dispersed and emulsified micro-droplets is easier.

With reference to Figure 6, there is shown, in a schematic diagram, the use of a coalescent filter for coalescing the FAEs and the removal of organic impurities majority of it are FAEs. The Coalescer 800 is formed from fibre 802 matrices. The filter is formed having many consecutive interconnected or intersected fibre components (4 illustrated in Fig. 6, for the purpose of concept explanation only), a first filler 804, a second filter 806, a third filter 808 and a fourth filter 810. The pore and fibre sizes increase from the first filter 804 towards the fourth filter, 810. The glycerine is fed through the filter 800, from the first filter 804 through to the fourth filter and in doing so, droplets 812 of FAEs (denoted FA) merge 814 along the fibres S02, so as form larger drops 816 which then gain rising velocity and rise to the top of glycerine liquid because of the difference gravities of the two liquid hence separates from glycerine The coalescence process can be a primary FAEs removal process to strip out the dispersed, emulsified and emulsified micro -droplets of FAEs. The coalescence process can also be used as a fine FAEs removal process by using higher density fibre matrices to strip out the remaining dispersed, emulsified and emulsified micro-droplets of FAEs still remaining in the glycerine solution after AUHGS and/or primary coalescence processes. In particular, the coalcscent filter is to remove the FAEs remaining in the glycerine liquid (denoted "FAEs" in Figure 6).

The coalesccnt filter works on the principle of coalescence separation, which is achieved by passing the liquid through a number of micro-droplets catching mechanisms (fibre matrices in this instance), making micro-droplets emerge and growing into much larger drops which are many times bigger in size.

As the results, the bigger FA drops gain stronger rising forces enabling themselves to separate from the glycerine phase because of difference in density or specific gravity.

The coalescent filter will merge tiny dispersed, emulsified and emulsified

FA micro-droplets into much larger drops/droplets. Larger size FA drops/droplets will gain enough force to overcome the viscosity and gravity of the liquid body and rise to the top of glycerine- water solution or separator, then easy to be cleared away by conventional methods.

Micro air-bubbles can also be used in conjunction with the coalescence separation as well as AUIIGS processes to achieve better FA separation. Vast amount of micTo air bubbles will attached to the surface of micro droplets of FA and bring the droplets to the top of glycerine solution. Other non-gas or rigid floating medium may affect equipment working efficiencies if being put to work in conjunction with either centrifugal or coalescent separations.

Actual equipment and/or devices to be installed will be determined by individual producers to their choices. Production operating parameters should follow the specifications of the glycerine refining system as well as the operating guidance issued by manufacturers of the installed equipment and/or devices.

The invention is not restricted to the details of the forgoing embodiment.

O:\410-420\LAK3\418412\GB\draftPCT.doc

Claims

1. A method for substantially purifying glycerine, the method comprising the step of subjecting a solution containing glycerine to one or more gravitational separation stages.

2. A method as claimed in claim 1 wherein the gravitational separation comprises gravitational liquid-liquid separation.

3. A method as claimed in claim 2 wherein the one or more gravitational liquid-liquid separations stages comprises any one or more of the following: general filtration, floating, coalescent filtration, accelerated ultra-high G-forcc separation, solvent extraction and washing, and absorption

4. A method as claimed in claim 3 wherein the gravitational force liquid-liquid separation comprises accelerated ultrahigh G-tbrce separation.

5. A meLhod as claimed in claim 4 wherein the accelerated ultra-high G- force liquid-liquid separation comprises acceleration of liquid or liquid ultra- centrifugat ion.

6. A method as claimed in any one of claims 3 to 5 wherein the one or more gravitational liquid-liquid separation stages comprises accelerated ultra-high G-forcc separation.

7. A method as claimed in any one of claims 3 to 6 wherein the one or more gravitational separation stages comprises accelerated ultra-high G-force separation, coalescent filtration, floating, solvent extraction and washing and absorption.

8. A method as claimed in claim 7 wherein accelerated ultrahigh G-force separation precedes in parallel with coalescent filtration and absorption or solvent extraction and washing process.

9. A method as claimed in claim 7 wherein accelerated ultrahigh G-force separation can also co-equalize with coalescent filtration and/or absorption.

10. A method as claimed in any one of claims 4 to 9, wherein the one or more glycerine solution centriiugation/acceleration stages comprises accelerating the liquid Io centrifugal separation factor in the range of 5, 000 to GO₅OOO or higher.

11. A method as claimed in any one of claims 4 to 10, wherein the one or more centrifugation stages comprises accelerating the liquid to two or more different centrifugal separation factors for a given period of time.

12. A method as claimed in claim 11, wherein the liquid is accelerated to a lower centrifugal separation factor for a given period of time and then accelerated to a higher centrifugal separation factor for a given period of time and to a constant centrifugal separation factor for a given period of time and to a constant and maximum centrifugal separation factor for a given period of time

13. A method as claimed in any preceding claim, wherein the ultra-high G- force separation stages are performed using a continuous feed centrifugal apparatus.

14. A method as claimed in claim 13, wherein the continuous feed centrifuge comprises a tubular centrifuge

15. A method as claimed in any preceding claim further comprising desalinisation and dcionisation.

16. A method as claimed in claim 15 wherein the method further comprises the step of desalinising the liquid to substantially remove salts.

17. A method as claimed in claim 13 to 14 wherein the desalinisation and deionising means utilises electro dialysis, electrodcionisation techniques, ion exchange or captive deionisation,

18. A method as claimed in any preceding claim, wherein prior to, or during purification, the glycerine solution is conditioned so as to adjust one or more parameters.

19. A method as claimed in claim 18, wherein the parameters are selected from one or more of the following: temperature, pressure, flow-rate, pH, hardness, softness and concentration

20. A method as claimed in any preceding claim, wherein after the glycerine solution has been passed through one or more ultra-centrifugation stages, the glycerine solution is passed through a fine coalescent filter or by-passed it.

21. A method as claimed in any preceding claim, wherein after the glycerine solution has been passed through one or more coaleεcent filtration stages, the glycerine solution is passed through a fine coalescent filter or by passed it.

22. A method as claimed in claim 20 to 21, wherein the coalescent filter comprises a fibre matrix.

23. A method as claimed in claim 20 to 21, wherein the fine coalescent filter comprises a fibre matrix with high density and/or finer filtration means

24. A method as claimed in any one of the previous claims further comprising an absorption step preceding or following coalescence.

25. A method as claimed in any preceding claim, wherein after removal of part or all of oTganic and inorganic impurities, the concentration of the glycerine is adjusted to a predetermined value.

26. A method as claimed in claim 25, wherein the liquid is concentrated by means of water evaporation.

27. A method as claimed in any preceding claim, wherein the liquid is heated or cooled to a pre-determiDed temperature prior to or during purification.

28. A method as claimed in claim 27, wherein the liquid is heated or cooled by means of heat recovery from within a step in the method.

29. A method as claimed in claim 28, wherein the heat recovery is at least partially achieved by means of heat-exchangers.

30. A method as claimed in any one of the previous claims further comprising the step of contacting the liquid with one or more washing agents.

31. A method as claimed in claim 309 wherein the washing agent comprises any one or more of the following: Acetone, Chloroform. Isoamyl acetate, Benzene, chlorbenzene, Ethyl chloracetate, ethyl alcohol, n-Heptane, etc.

32. A method as claimed in any one of the previous claims further comprising the step of polishing.

33. An apparatus for substantially purifying glycerine, the apparatus comprising gravitational separation means.

34. An apparatus as claimed in claim 33 further comprising a coalescent filter located at the same process level and/or downstrean of the accelerated ultra-high G-force separation means.

35. An apparatus as claimed in claim 34, further comprising a filter means located between the centrifugation means and the deionisation means

36. An apparatus as claimed in claims 33, 34 or 35, wherein the apparatus iurther comprises a desalination device.

37. An apparatus as claimed ill any one of claims 33 to 36, wherein the apparatus further comprises a conditioning means to adjust one or more parameters of the glycerine solution selected from the following: temperature, pressure, pH, harness, softness and concentration.

38. Λn apparatus as claimed in any one of claims 33 to 37, wherein the apparatus further comprises a concentration device to remove moisture and excess water from, the glycerine solution.

39. An apparatus as claimed in claim 3 S, wherein the concentration device comprises a water evaporator.

40. An apparatus as claimed in any one of claims 33 to 39, wherein the apparatus further comprises one or more filters.

41. An apparatus as claimed in claim 40, wherein the apparatus further comprises a washing means adapted to supply a washing fluid to the filters and/or other components of the apparatus.

42. An apparatus as claimed in any one of claims 33 to 41 , wherein the apparatus further comprises a heating or cooling means for heating or cooling the glycerine solution.

43. An apparatus as claimed in claim 42, wherein the heating and/or cooling means is coupled to a heat exchanger.

44. An apparatus as claimed in any one of claims 33 to 43, wherein the apparatus is used to perform the method as claimed in any one of claims 1 to 32.

45. A method for substantially purifying glycerine from liquids, the method comprising the steps of passing the liquid through one or more gravitational separation stages and a deionisation means.

46. A method for substantially purifying glycerine, the method comprising the steps of passing the glycerine through one or more ultra-centrifugation stages and a deionisation means.

47. A method as claimed in any one of the previous claims further comprising the pre-step of filtration and/or floatation.

48. A method as claimed in any one of the previous claims comprising AUGHS, coalescence, floating and/or SEWP.

49. A method as claimed in any one of the previous claims wherein the ratio of floating agent to Glycerine is in the range from 1:1,000 to 200:1, 1:20 - 20:1 or 1:5 - 5:1.

50. A method as claimed in any one of the previous claims wherein the ratio of solvent to Glycerine is in the range from 1 :1,000 to 200:1, 1:20 - 20:1 or 1:5 - 5:1.

51. A method as claimed in any one of the previous claims wherein the solvent comprises any one or more organic and/or inorganic solvent.

52. A method as claimed in claim 51 comprising the use of one or more solvent having one or more of the following properties: a. immiscible or almost immiscible or very slightly miscible with glycerol, and/or b. miscible or partial miscible or immiscible or almost immiscible or very slightly miscible with water, and c. has significant density difference from the density of glycerol- water solution and has significant density difference from water if miscible or partial miscible with water; and/or d. has significant lower boiling pint than the glycerol- water solution

53. A method as claimed in claim 51 wherein the solvent comprises any one or more of the following: Acetone, Chloroform, Isoamyl acetate, Benzene, chlorbenzene, Ethyl chloracetate, ethyl alcohol, n-Hcptane, etc and/or any mixtures thereof

54. An apparatus for substantially purifying glycerine, the apparatus comprising accelerated ultra-high G- force separation means located at the same level at least one coalescent filtration means.

55. An apparatus for substantially purifying glycerine, the apparatus comprising accelerated ultra-high G-force separation means located upstream of at least one coalescent filtration means.

56. An apparatus as claimed in claim 54 or 55 wherein the coalescent filtration means comprises at least one suspended and/or dispersed and/or emulsified free fatty acids and esters catching matrix.

57. An apparatus as claimed in claim 56 wherein the coalescent filtration means comprises a plurality of suspended and/or dispersed and/or emulsified free fatty acids and esters catching matrices.

58. An apparatus as claimed in claim 57 wherein the matrices comprise a filter having a given fibre and pore sizes.

59. An apparatus as claimed in claim 58 wherein there are two or more matrices, the fibre and pore sizes between successive matrices being different.

60. An apparatus as claimed in claim 59 wherein the matrices are arranged such that the liquid flows from matrices having smaller fibre and pore sizes to those having a larger fibre and pore sizes.

61. An apparatus as claimed in any one of claims 54 to 60 wherein the matrix comprises a filter.

62. An apparatus as claimed in any one of claims 54 to 61 wherein the filter comprises a hydrophobic or non- hydrophilic and/or non-hydrophobic materials.

63. An apparatus as claimed in claim 62 wherein the filter comprises any one or more materials selected from the group comprising; polypropylene fibres, ceramic fibres, ceramic powders and/or glass fibre.

64. An apparatus for substantially purifying glycerine, the apparatus comprising a ultra-centrifugation means located upstream of a deionisation means.

65. Glycerine purified according to the method as claimed in any one of claims 1 to 53.

66. A method for substantially purifying glycerine from liquids, the method comprising the steps of passing lbe liquid through one or more centrifugation stages and a deionisation means.