CN1040995C

CN1040995C - Process to re-refine used oils

Info

Publication number: CN1040995C
Application number: CN93118174A
Authority: CN
Inventors: J·A·G·米那纳; R·希尔佩蒂; F·D·乔宛纳
Original assignee: VISCOLUBE ITALIANA SpA
Current assignee: VISCOLUBE ITALIANA SpA
Priority date: 1992-09-30
Filing date: 1993-09-29
Publication date: 1998-12-02
Anticipated expiration: 2013-09-29
Also published as: HU9401725D0; ITMI922271A1; TJ335B; DE69324905D1; SA95150447A; RU2099397C1; PL171473B1; EG20181A; ITMI922271A0; EP0618959B1; ATE180009T1; HK1013280A1; CN1086252A; CZ157994A3; PL297417A1; GR3030648T3; HUT68935A; CZ287418B6; WO1994007798A1; ES2132258T3

Abstract

Process to re-refine used oils, wherein the oils (A1) are initially subjected to a pretreatment (A) with a basic reagent (A2), then to a first preflash treatment (B) to eliminate the water (B1) and the most volatile fractions (B2) contained therein, and finally to a combined treatment of fractional distillation and of purification to eliminate the high polymers and heavy metals, carried out into a single filled-type column (21), in order to obtain one or more fractions of re-refined oils. The separation of the high polymers and heavy metals takes place, together with a cut of very heavy and viscous oils, from the bottom of the column (21) by means of a cyclone device (23). The re-refined oils (C3) are then subjected to a suitable decolorization treatment (D) and can be used as base oils for the production of lubrification oils.

Description

The method of re-refine used oils

The present invention relates to the method for a kind of high yield and the oligosaprobic waste lubricating oil of refining again.In this particular technology area, term " refining again " refers to and will change base oil into from engine and the waste oil of discharging and degras fat from other industrial use.With after suitable additive mixes, such base oil can be used as new lubricating oil, and its qualitative features safely challenges comparison with directly by the resulting oil of petroleum refining.

Nineteen sixties first has occurred and has been used for the factory of re-refine used oils, has been mainly to solve the serious ecological problem that soil or water treatment because of waste oil cause.In some years after this, on the one hand owing to the increase of consuming, on the other hand, because the raising of the cost of the virgin oil of initial refining makes refining oil have the critical positions that improves day by day again, even as raw material.Now, not only can say, and with regard to cost with regard to available, again refining oil all and directly from oil obtain oily equally matched.

The interest economically that recovered oil is increased day by day makes that government organs collect it and thickening problem is more paid close attention to, and has established federation to collect waste oil, and all users must provide waste oil to it.This trend is so far still in abundant development, in fact, in EU member country, about 400 ten thousand tons of the year consumption amounts of lubricating oil, the amount of callable waste oil equals about 200 50 ten thousand tons on its corresponding theory, have only 100 50 ten thousand tons of described waste oil in fact to be collected and to deliver to refining center again, the waste oil of its surplus is discharged from non-control mode, so be harmful to environment certainly.

Many two kinds of methods that have basically in common knowledge and that adopt technically can be carried out the refining again of waste oil: sulfuric acid method and propane method.In these two kinds of methods, at first remove water contained in the waste oil, purify with sulfuric acid or propane respectively then, to remove other impurity that exists.The latter mainly comprises high-molecular weight compounds contained in the oil additive, and or is directed to the metal of metal parts wearing and tearing, the perhaps metal of secondary source in fuel or oil additive, for example lead in the oil.

The sulfuric acid method is that first is familiar with and adopts, but is reducing use now, because it can cause the pollution problem of significant.Described method consists essentially of following step, and shown in the functional diagram of Fig. 1: A-is preflash waste oil A1 under medium vacuum, separating the overhead distillate of forming by water A2 and lighter hydrocarbons A3 (gas oil), and the tailings of forming by dehydrated oil A4.B-handles dehydrated oil A4 with the vitriol oil of 20-25wt%, and to obtain extract, decant has the high-molecular weight compound then, and the decant heavy metal; And

-with purified and acidifying oil B3 with have the acid sludge B2 that high-content contains oil distillate and be separated; C-oily the B3 that neutralizes, and with the mixture C 1 of lime and discoloring clay it is decoloured; And

-filter described oil, obtain the neutral oil C3 of decolouring and recovery and absorbed the roach C2 that high density contains oil distillate; D-high temperature underpressure distillation oil C3 isolates process water and gas oil D1 from cat head, and from the side exit of tower again refining oil D2 be separated into the different cut of viscosity; Go into superheated vapour from the tower rising pouring; E-oil is decoloured at last with discoloring clay E1 obtains lubricant base E3, reclaims to have absorbed the roach E2 that high density contains oil distillate.

Fig. 1 also expresses the fluid mass that flows into and flow out each single square, is 100 with the inlet flow rate of waste oil A1.This shows the ultimate yield of sulfur process even does not reach 60%.

In fact, in acid sludge B2, contain the oil of a great deal of, but be difficult for therefrom reclaiming.The composition of described slag is in fact quite different, and comprises except that sulfuric acid and hydrocarbon compound, having high molecular weight polymers, organic or inorganic compound sulphur, chlorine, nitrogen and phosphorus, and heavy metal for example chromium, copper, zinc, iron, nickel and lead.

The solution (still adopting in existing factory) of eliminating such refuse on the ecology is to discharge with refuse or silica.Be everlasting with discharging in the lime and after the acid sludge, but make the volume and the discharge fee that can roll up discharge like this,, need the lime of 0.4-0.5 kilogram because to the per kilogram acid sludge.Also should not use incineration technology, because need foundation and complicated operation and expensive equipment to purify cigarette.

(volume is less mainly due to the pollution damage that causes because of the discharging acid sludge, but it endangers all infringements not second to causing by direct discharging waste oil), in a single day second kind of currently known methods of propane on market, occur utilizing, just stopped utilizing the new foundation of refinery plant again of vitriolic rapidly.

The functional diagram of second method as shown in Figure 2, its describing mode is similar to the description to above-mentioned sulfuric acid method, in the case, has also pointed out to flow into and flow out the different flow of single square, is 100 with the A1 flow of sending into.In the propane method, acid treatment step is entirely replaced by the operation B that purifies with petrogas.

In fact, described hydrocarbon easily is liquefied, and density of liquid phase is low.When mixing with waste oil, propane is separated the first liquid distillate B1 and the second liquid distillate B2 as thinner and liquid agent.This first liquid distillate B1 has high viscosity, contains high polymers and heavy metal, usually with " pitch " expression.This second liquid distillate B2 only comprise purifying with the dehydration oil.Certainly, provide the depropanizing processing of liquid distillate B2 and the device of the propane that circulation is reclaimed.

By thermal treatment, carry out successive filtration step C with discoloring clay C1, the result has not only reclaimed roach C2, and has reclaimed gaseous fraction C3, and it comprises that little part is contained in the gas oil among the B2.All the other gas oils are discharged with bleached oil C4, and reclaim with the D1 form in follow-up distilation steps D.Distilation steps D and final decolouring step e and preceding described identical are referring to the sulfuric acid method.

The propane method has significantly been improved the sulfuric acid method, is not only productive rate and is increased to approximately 68%, and pollutes and has reduced significantly.However, this method still has some inconvenience.At first, because its explosivity uses propane that the workman is caused safety problem, and, although above-mentioned depropanizing operation is arranged, still contain the propane of trace in the last running of pitch B1.The field that has interest as build the road and building field in, even a spot of propane also is hinder to use such pitch.In fact, the existence of propane is tending towards increasing significantly bituminous combustibility.On the one hand when formation bituminous matter road surface, be difficult to handle them, on the other hand, stoped its application, promptly form seal coating at the most interesting building field.In fact, the seal coating that forms with this pitch can not carry out melting welding and not have fire as common doing.

As a result, in the propane method, in all its bearings, pitch should be considered to waste product.By diluting with gas oil earlier, make it have sufficient flowability, the general then fuel that has high heating value but have the high pollution rate that is used as.It generally is used in the quenching furnance, provides special equipment with smoke evacuation in this quenching furnance, and also has been easy to eliminate existing pollutent in this pitch.

At last, from the energy viewpoint, the propane method is more desirable than sulfuric acid method, not only according to power consumption, and according to the fuel consumption of production technique steam and heated oil.

In recent years, develop the method for the third type, wherein, after traditional dehydrating step, waste oil has been delivered to thin film distillation technology.In described continuation method, waste oil is sent to heat and steams in the axle rotating cylinder (rotor) of tower, from described rotating cylinder, they is sprayed on the inwall of tower, by the heat-conducting liquid in the lining that flows to described tower, makes interior empty the maintenance at high temperature of tower.

Contact with the tower wall, but the light evaporated fraction of oil becomes gas phase immediately, and last running still is liquid, and enters the bottom of tower.Collect evaporated fraction then, and fractionation becomes desired cut in follow-up separation column.

This continuation method has high yield, but its development of a series of drawbacks limit is arranged.At first, need pre-treatment with purification waste oil, so that ongoing operation considerable time, and extra clean operation needn't be provided; Especially, it is very difficult that the existence of rotating cylinder makes that the dirt of this method stops up, and periodic cleaning is very expensive.Secondly, described method needs with high investment and working cost, and this can't compete mutually with the propane method economically.At last, owing to have to limit the height (this be because need pull out rotating cylinder fully in order to clean) of wiped film distillation column, if when feed rate is very big, need to use the tower of several parallel connections, this just makes being on a grand scale of equipment.

The purpose that the present inventor proposes a kind of technology of re-refine used oils is, reduces or abandons fully using and be difficult to discharging or harmful or to the adventurous reagent of personnel safety to environment; Adopt simple and small-sized equipment, do not increase production cost, cut down the consumption of energy; Operate in static fully equipment, single component does not wherein comprise the moving-member that very easily causes the dirt blockage problem in any typical waste oil treatment; And last, the still unsafty productive rate of raising already known processes not only improves the quality and quantity of recovered oil, and the possibility of the utilization of its pair product is provided, and to bring interests economically, makes described technology have bigger advantage.

According to the present invention, for reaching described purpose, in the re-refine used oils method of the type, described waste oil at first carries out preflash to be handled, to remove wherein contained water and most volatile fraction, carry out purification processes to remove high polymers and heavy metal, distill fractionation and handle, to obtain one or more distillates, as lubricant base, the processing of decolouring at last the method is characterized in that:

-described distillation fractionation is handled and is carried out in one filled-type tower;

-described purification processes is carried out with three consecutive steps: the first step pre-treatment, before described preflash is handled, add highly basic reagent, and make it to mix with oil; Second step, before the distillation fractionation is handled, the oil that decant is handled from preflash; Third step is discharged the heavy-fluid body cut that contains described superpolymer and heavy metal from the bottom of described separation column.

In order to be illustrated more clearly in the further feature and advantage of method of refining more of the present invention, below will be with reference to the accompanying drawings, describe a preferred device of implementing this method in detail, wherein:

Fig. 1 is a functional diagram, and the sulfuric acid that known type is described is method of refining again;

Fig. 2 is a functional diagram, and the propane that known type is described is method of refining again;

Fig. 3 is a functional diagram, and the method for re-refine used oils of the present invention is described;

Fig. 4 is a setting drawing of implementing the inventive method, and wherein alkaline reagents interpolation step and preflash step are illustrated in greater detail; And

Fig. 5 is a setting drawing of implementing the inventive method, wherein distills fractionating step and separates the last running step that contains high polymers and heavy metal and illustrated in greater detail.

The method of re-refine used oils of the present invention is different from currently known methods, because it has simplified purification processes significantly, and all distillations are handled (in currently known methods, they carry out in several placed in-line towers) and the operation that separates the last running contain superpolymer and heavy metal, be incorporated in the independent tower.And last separation is to be undertaken by the cyclonic separator that is positioned at the distillation tower bottom, and distillation tower does not require and uses any moving parts, so can not take place because the high viscosity and the caused dirt blocking problem of special composition of the material of handling.

Fig. 3 is the functional diagram of explanation the inventive method key step.As Fig. 1 and Fig. 2 of the aforementioned already known processes of similar explanation, this figure has indicated the fluid mass that flows into and flow out single square, is 100 with the flow of sending into of waste oil A1.

As mentioned above, the processing of removing superpolymer and heavy metal of purification waste oil comprises with alkaline reagents and carries out pre-treatment A.For this purpose, preferred reagent is , before preflash is handled, will Be added among the A2, and mix with oily A1.Described pre-treatment does not directly act on the above-mentioned pollutent, but helps the wherein contained lipid acid of saponification on the one hand, impels its precipitation, the chlorine that neutralizes on the other hand and exist with bonding and free form.The saponification of lipid acid is except that helping being removed by decant, so improve the flowability of system, also destroy its volatility, so stoped the gasification of described acid in distillation tower, and the result of this gasification has directly polluted oil, has perhaps finally polluted the oil on it by polluting parts.Equipment has also been protected in the neutralization of chlorine, the kept away rabbit dangerous phenomenon of corrosive, the working life that has prolonged it.

Follow-up preflash treatments B relates to-as in the technology of known technology-separate butyraceous current B1 and gas oil stream B2.Before delivering to subsequent step, the dehydrated oil B3 that derives from the preflash processing will leave standstill for some time, is enough to make saponification or flocculation part decant to come out.

Deliver to hot diasphaltene processing and distillation fractionation processing C through the oily stream of above-mentioned processing, the distillation fractionation is handled C and is related to the separation of the light phase C1 that contains gas oil and separating of the heavy phase C2 that contains superpolymer and heavy metal simultaneously, and oil content heats up in a steamer and becomes three kinds of cut C3 with different densities.Be suitable for handling the cut of purifying with thus obtained these three kinds and deliver to last decolouring processing D (itself is known) by stripping, to wherein sending into discoloring clay stream D1, and therefrom shift out roach stream D2, and therefore obtaining again the main flow D3 of refining oil, productive rate is up to about 72%.As adding a step again, promptly reclaim the oil be absorbed among the roach D2, productive rate even can bring up to 75%.Another kind method is that the decolouring of refining oil D3 can be carried out with hydrogen treat again, also is well-known technically.

With reference to the equipment of representing among figure 4 and Fig. 5, describe square A in detail, the processing step among B and the C.

Fig. 4 illustrates square A and B.By pump 1 waste oil A1 is sent in the preflash tower 2.Alkaline reagents A2 also sends in the described pump outlet, by volume pump 3 dominant discharge.As above specified, described reagent preferably includes , add with 30% solution, its amount should make waste oil at the pH value in the exit of tower 2 between 10 and 13, preferably between 11.8 and 12.2.So the PH control device 4 in the exit by being positioned at tower 2 is regulated the flow of pump 3 automatically.

Waste oil A1 and reagent A 2 enter line mixing tank 5 thorough mixing, then are preheated to about 120 °-140 ℃ temperature in heat exchanger 6.This heat exchanger is by vapour line VAP heat supply.

Preflash tower 2 is remained under the medium vacuum degree, equal about 200mmHg.Keep this vacuum tightness by means of a squirt pump 7 that links to each other with vapour line VAP.The stream A3 that will send into then in the tower 2 is separated into the vapor phase that contains water and gas oil and contains dehydrated oil and the liquid phase of pollutent.By water-cooled condenser 8a with the vapor phase condensation and deliver to gravity separator 9.Steam from squirt pump 7 after the condensation, also enters this separator 9 in condenser 8b.

Separator 9 is isolated uncondensable gas phase GAS from two liquid stream B1 that stated and B2, it is delivered to high temperature combustion furnace, to destroy any gaseous pollutant that wherein exists by fire.Slightly,, deliver to together in the ecological purification device together with the process water of discharging in other device by the current B1 of oil pollution.This is actually the unique waste product in the inventive method, and waste water is no more than sends into 4% of material weight, can not cause any special problem to its normal eliminating.The gas oil B2 of excellent quality because oil is not handled with contamination reagent, can send into normal commercial fuel channel.

By the bottom product B3 of cooling ring 10 condensations, send in the holding tank 12 at last by pump 11.Calculate good jar 12 the size and the position of inlet outlet line, make the B3 stream residence time therein be at least 48 hours.In this way, use Handle and saponified lipid acid and other flocculation partly can termly with its discharge, carried a certain amount of impurity by vent pipe 13 secretly at the bottom of jar 12 decant.

Fig. 5 represents the hot diasphaltene that dehydrated oil stream B3 is carried out and distills fractionation and handle.At first in methane gas stove 20, described oil is heated to about 300 ℃ temperature.Then oil is delivered to the bottom of separation column 21, wherein vacuum tightness remains 10-20mmHg (at cat head) at least.Two

secondary squirt pump

22b and 22c by main injection pump 22a that all links to each other with the VAP pipeline and serial connection keep real brightness.More accurately, be sent to the top of cyclonic separator 23 through the oil with partly gasification of heating, this cyclonic separator is positioned at the bottom of tower 21, comprise that one is opened spiral (open-spvial) passage around big pipe core with what spiral down, big pipe core has connected the bottom of tower and the top of its adjacency.

In the ingress of tower 21, stream B3 almost completely gasifies, and cyclonic separator 23 makes gas phase separate for a full due from liquid phase, contains very heavy oil distillate and all pollutents in the liquid phase, and pollutent comprises superpolymer and heavy metal.Liquid phase C2 often is called " pitch ", delivers to holding tank by pump 24.

The gas phase that discharges from cyclonic separator 23 moves up along tower 21, runs into four tactic packing layers 25, these packing layers are positioned at these filler plates on each liquid collecting plate 26, in known manner, allow to rise and pass through, and retain the liquid of condensation to the gas phase at top.Separation column 21 of the present invention so designs, make and enter flow point and heat up in a steamer and become the overhead distillate that mainly contains process steam and gas oil, three middle runningss with refining oil again of different densities (are labeled as C3/I, C3/II and C3/III, can be used for different commercial uses), and the tailings C2 that had described.

For obtaining this result, filler should have very low resistance to flow (every layer of filler is at most 5-10mmHg), and high gas/liquid surface in contact.In order to obtain fabulous result, use metallic stuffing, comprise that side by side synergetic, the metal sheet of folding shape forms the crooked passage that spirals steam is risen, its mean sizes is 1 to several centimetres.Such filler is made by stainless steel, by Glitsch Italiana, and Campoverdedi Aprilia (Latina), Italy makes, and commercially available trade mark is GEMPACK.

At top liquid collecting plate 26a, promptly be positioned at the liquid distillate of collecting on the liquid collecting plate below the first layer filler 25, by pump 27a, flow into the tower district that just is positioned at described liquid collecting plate under again, and after water interchanger 28 cooled off, it was sent to the top of tower 21.Surpass the part that needs that refluxes and in C1, collect,, can put on market together with isolating stream B2 in the preflash step in front as gas oil.

The liquid distillate of collecting on two liquid collecting plate 26b of lower floor and 26c flows into the just tower district under described liquid collecting plate again respectively by recycle pump 27b and 27c.The part of these two liquid distillates that surpassing refluxes needs is sent to respectively in the different intervals of the stripping tower 29 with three different intervals, and the liquid distillate of collecting on the liquid collecting plate 26d of bottom also flows directly in these three intervals.In three intervals of stripping tower, by with from the VAP pipeline and in stove 20 superheated water vapor counter current contact, these three liquid distillates are further purified.

The liquid distillate of collecting in stripping tower 29, by pump 30b, 30c and 30d behind air-cooler 31, finally deliver to holding tank.

From main injection pump 22a with from the stream of

secondary squirt pump

22b and 22c, contain process steam, uncondensable gas and gas oil steam, condensation in water condenser 32 is collected then and is entered gravity phase separator 33.In separator 33, will from technology water and uncondensable gas phase, separate from the gas oil phase of overflowing in the top of tower 21.Gas oil is sent C1 to, carried out possibly depolluting handle after, current 34 are recycled to steam and produce vaporizer; And uncondensable gas is sent into GAS, enters roasting kiln then to eliminate any possible dusty gas.

The cut of refining oil again of Huo Deing like this, heavy oil C3/I, middle oily C3/II, light oil C3/III is admitted to final decolouring device, with public and mode, described oil with the processing of decolouring of discoloring clay or hydrogen, is made it to be suitable for market demands.

Owing to not having solvent and in fact containing, as the carrier of pollutent, very heavy very sticking oil distillate (bright stock), asphalt oil C2 can be commercially available, in favourable economically mode, forms bitum road surface, makes it to have special snappiness and noise reduction characteristic.

The technology of re-refine used oils of the present invention is compared favourable especially with known technology.In fact, decapacitation is implemented with quite simple device, thereby reduces outside the installation costs, owing to do not have moving parts fully in alkaline purification pre-treatment and the equipment, has also reduced the demand to periodicmaintenance.

As for running cost, method of the present invention has very high competitive power, referring to following comparison sheet.These statistical tables and reports have been accused the cost of running stores, and handle the required expense of waste material.As can be seen, it is 25% of a cost that sulfur process requires, is 60% of propane cost that technology requires.

At last, the waste material that is produced in present method only is included in the preflash step isolated water from oil.The amount of described water is very little, is initially to send into about 4% of material A1.With regard to the discharge problem, as mentioned above, in any case do not cause ecological problem.

Table

Product (waste oil per ton)	Technology type
Product (waste oil per ton)	Technology type	Running stores: Sweet natural gas electric current additive reagent propane acid nitrogen decolouring handmade paper, desires such as strainer are discharged: the roach acid sludge	The present invention of sulfuric acid propane
SM ³ 160.2 215.8 98.61 Kwh 75.6 102 58.53 US$ 3.44 4.9 2 Kg - - 17 Kg - 5 - Kg 178.3 - - Kg 2.5 2.5 2.35 Kg 88.9 119.4 81.5 US$ 2.08 1 2 Kg 239.87 190.67 131 Kg 356.25 - -			The present invention of sulfuric acid propane
	Total expenses		US$ 200 100 60
(waste oil per ton) productive rate total expenses	Total expenses

		58.2％ 68.79％ 72％
	US$ 344 145 83	58.2％ 68.79％ 72％
		(generating refining oil more per ton) reference price :-Sweet natural gas-electric current-reagent-propane-acid-nitrogen-discoloring clay-discharge roach-discharge acid sludge
US$/Sm ³ 0.18 US$/Kwh 0.095 US$/Kg 0.16 US$/Kg 0.45 US$/Kg 0.12 US$/Kg 0.37 US$/Kg 0.25 US$/Kg 0.056 US$/Kg 0.28

Claims

1. the method for a re-refine used oils, wherein said waste oil (A1) is handled (B) to remove water (B1) and the most volatile fraction (B2) that wherein contains through first preflash, through purification processes to remove superpolymer and heavy metal, handle (C) to obtain the oil distillate that one or more can be used as lubricant base through the distillation fractionation, handle (D), it is characterized in that after decolour:

-described distillation fractionation is handled (C) and is carried out in one filled-type tower (21);

-described purification processes is carried out with three consecutive steps: first step pre-treatment (A), handle (B) before in described preflash, add highly basic reagent (A2) and mix second step mutually with oil (A1), handle (C) before in the distillation fractionation, decant is handled the oil (B3) of (B) from preflash; Third step is discharged the heavy-fluid body cut (C2) that contains described superpolymer and heavy metal from the bottom of described separation column (21).

2. according to the process of claim 1 wherein that described filled-type separation column (21) is a level Four tower, total resistance to flow is no more than 40mmHg.

3. according to the process of claim 1 wherein that described filled-type separation column (21) is a level Four tower, total resistance to flow is no more than 20mmHg.

4. according to the process of claim 1 wherein that the filler (25) in the described tower (21) comprises side by side, synergetic, the metal sheet of folding shape.

5. according to the method for claim 1, wherein be admitted to the cyclonic separator (23) of the bottom that is arranged in separation column (21) from the oil (B3) of preflash processing (B), this oil is separated into gaseous fraction and contains the heavy-fluid body cut (C2) of superpolymer and heavy metal in this cyclonic separator, gaseous fraction is sent to the top of tower (21), and heavy-fluid body cut is discharged from.

6. according to the process of claim 1 wherein described separation column (21), even, all there is not movable part in the tower bottom that cyclonic separator is housed.

7. according to the process of claim 1 wherein that described highly basic reagent (A2) is 。

8. according to the method for claim 7, the introducing amount of wherein said reagent (A2) is enough to make pH value from the dehydrated oil of preflash step between 10 to 13, preferably, and between 11.8 and 12.8.

9. according to the process of claim 1 wherein that described decant carries out in jar (12), jar (12) are positioned between preflash tower (2) and the separation column (21), and the residence time is at least 48 hours.

According to the process of claim 1 wherein from separation column (21) discharge (C3/I, II III), decolouring processing (D) before, handle in stripping tower (29) through the distillatory oil distillate.

11. according to the process of claim 1 wherein that described decolouring handles (D) and carry out with discoloring clay (D1).

12. according to the process of claim 1 wherein that (D) handled in described decolouring is hydrogen treat.