CN1922292A - Fuel for homogeneous charge compression ignition (HCCI) systems and a process for production of said fuel - Google Patents

Abstract

The invention provides a HCCI fuel or fuel component, which fuel includes at least n-paraffins and iso-paraffins having from 7 to 14 carbon atoms, and which fuel has an ignition delay of less than 7 ms, according to ASTM D6890. A process for preparing a HCCI fuel or fuel component.

Description

Be used for evenly filling the fuel of ignition (HCCI) system and the method for preparing described fuel

Invention field

The present invention relates to be used for evenly filling the fuel of ignition (HCCI) system and relate to the method for preparing this fuel.

Background technology

The HCCI engine is the relative new notion of being developed by some mechanisms and company.HCCI incendiary principle is: dilution, premix, with the homogeneous mixture of Piston Compression fuel and air the time its in whole cylinder volume internal reaction and burning.When mixture reached sufficiently high temperature, combustion reactions began with automatic igniting.These are reflected at many places and cause simultaneously, and it is very fast to carry out ground, and does not have localized high temperature regions or flame front fully.

In fact, described HCCI combustion method is sought be will be relevant with petrol engine low NOx (NOx) exhaust gas emission and the high thermal efficiency relevant with diesel motor or ignition (CI) engine combine.In theory, the possibility below HCCI provides: smokeless combustion and low-down oxynitride (NOx), and the energy efficiency that can be higher than the CI engine.

Therefore, realize that successfully the HCCI burning will increase the competitiveness of internal combustion (IC) engine for energy technologies (for example fuel cell), the lifetime (lifespan) that prolongs them thus.

Because HCCI has improved the IC engine effectively, do not hinder so do not exist, and the progressively employing of this technology as can be seen for the outside of its enforcement, its with various forms finally in main motor vehicle IC engine.In USDOE (US Department ofEnergy) prediction in the calendar year 2001 degree report that US Congress makes, along with successfully research and development, the passenger vehicle hcci engine can be commercialization in 2010.

Therefore exist being used for the demand of HCCI system and motor spirit.

Summary of the invention

According to an aspect of the present invention, provide HCCI fuel, this fuel comprises n-paraffin and isoparaffin at least, and this fuel has the spark delay that is lower than 7ms.This HCCI fuel also can be used as fuel element.

Usually, this fuel contains the hydro carbons of 7-14 carbon atom.

Described fuel can be substantially free of naphthenic hydrocarbon (cyclo-paraffin).Like this, described fuel can contain and is lower than 5 quality %, is usually less than the naphthenic hydrocarbon of 1 quality %.

In addition, its sulphur that contains the aromatic substance that is lower than 1wt% and can ignore degree.

In this manual, spark delay uses ASTM Method D6890 in the equal-volume incendiary projectile, igniting attribute test instrument (IQT ^TM) record.

The spark delay of fuel can be for being lower than 5ms.

The spark delay of fuel can be 2-5ms.

The weight % of n-paraffin can surpass any other one-component in the fuel.

N-paraffin can surpass 25 weight % of fuel.

N-paraffin can surpass 50 weight % of fuel.

N-paraffin can surpass 80 weight % of fuel.

N-paraffin can be about 95 weight % of fuel.

N-paraffin can be the n-paraffin that is obtained by Fischer-Tropsch (FT) reaction.

Isoparaffin can be the isoparaffin that is obtained by the FT reaction.

Fuel can contain alkene.

Described HCCI fuel can comprise oxide compound (oxygenate).

Described HCCI fuel can be substantially free of sulphur.

Described HCCI fuel can be substantially free of oxide compound.

Described fuel can have 90 ℃-270 ℃ ASTM D86 overhead product.

Described fuel comprises lubrication modifier and other fuel dope, makes to meet product specification.

Described fuel can be used as blend components and uses with conventional oil.

The invention provides the method for preparing HCCI fuel or fuel element, this fuel or fuel element comprise n-paraffin and isoparaffin at least, and this fuel has the spark delay that is lower than 7ms, and described method comprises and is selected from one or more following step:

A) the condensate fraction or derivatives thereof of hydrotreatment at least a portion Fischer-Tropsch (FT) building-up reactions product;

B) hydrogenation transforms the wax slop or derivatives thereof of FT synthetic product;

C) one or more hydrogenation conversion cuts through the condensate fraction and the step b) of the step a) of hydrotreatment of fractionation in single unit or separate units are to obtain ideal HCCI fuel or fuel fraction; And

D) randomly, with the two kinds or more of described components of required ratio blend, to obtain ideal HCCI fuel from step c).

Hydrogenation transforms and can be undertaken by hydrocracking.

According to this method prepared fuel character can be that any position is open hereinbefore and in specification sheets.

The blend of step d) can be that the FT wax derivative that transforms of FT condensation derivative and hydrogenation was with volume ratio blend in 1: 99 to 99: 1.

The typical case who has provided two kinds of cuts in the following table forms.

Typical FT product after being separated into two kinds of cuts (through distillatory volume %)

	FT condensation product (＜270 ℃ of cuts)	FT wax (＞270 ℃ of cuts)
			C5-160℃ 160-270℃ 270-370℃ 370-500℃ ＞500℃	44 43 13	3 4 25 40 28

The boiling point that contains significant quantity greater than 160 ℃ cuts is higher than the hydrocarbon materials of general petroleum naphtha.160 ℃-270 ℃ cut can be considered as light diesel fuel.This means that all material requires that overweight 270 ℃ are converted into lighter material by catalysis process (being commonly referred to hydrotreatment, for example hydrocracking).

The catalyzer that one of is used for step is the difunctionality type normally; That is to say: they contain the avtive spot that is useful on the cracked avtive spot and is used for hydrogenation.The catalytic metal active substance that is used for hydrogenation comprises the precious metal of VIII family, for example platinum and palladium or vulcanized VIII family base metal, and for example nickel, cobalt, it can comprise or not comprise vulcanized VI family metal, for example molybdenum.These metallic carriers can be any refractory oxide, the oxide compound of silicon oxide, aluminum oxide, titanium oxide, zirconium white, vanadium oxide or other III family, IV family, V family and VI family for example, and it can use separately or be used in combination with other refractory oxide.Alternatively, described carrier can partly or completely be made up of zeolite.

Specifically describe and embodiment

Following form has been summed up raw material and the carbon number range that is applicable to the recommendation fuel of hcci engine of the present invention.

Type	Typically (LTFT) charging	Form	Carbon number range
						C 7-C 9	C 7-C 14	C 10-C 14
			SR FT	The FT condensation product	Paraffinic hydrocarbons, alkene and oxygenant				X	X	X
HT SR FT	The FT condensation product	Major part is a linear paraffins				X	X	X
			HX FT	FT wax	Great majority are isoparaffin				X	X	X
GTL	FT condensation product and wax	It all is paraffinic hydrocarbons				X	X	X

Definition

SR FT: straight run fischer-tropsch reaction

HT SR FT: the delay fischer-tropsch reaction of hydrotreatment

HX FT: the fischer-tropsch reaction of hydrocracking

GTL: by the hydrogenation converted product of expection from fischer-tropsch reaction gas-liquid transfer equipment.

Described fuel can contain the hydro carbons with 7-14 carbon atom, and has been found the unique property that meets aspect vapour pressure and spark delay.In addition, standard has also been considered the highly paraffinic essence of fuel and the high straight chain of hydro carbons.

The carbon number range that has been found that C7-C14 does not comprise the pentane that for example has high-vapor-pressure and the hydrocarbon of hexane.Enough volatility are filled for the gas of setting up homogeneous in the combustion chamber and enough n-Hexadecane eigenwerts (tendency of igniting automatically), are important thereby light equably in whole volume.

The carbon number range that has been found that C7-C14 does not in addition comprise the hydrocarbon of the n-hexadecane that for example has 100 cetane value usually.The n-hexadecane number of HCCI fuel must not be too high and its spark delay must not be too short, to guarantee controlled combustor inner cylinder.

The inventor believes that ten binomials select almost to have summarized all actual selection for the synthetic HCCI fuel of FT base.

Crucial quality requirements for these fuel is summarized in table 1.

Table 1: the selected qualitative characteristics of synthetic FT HCCI fuel

	Ideal range	Routine analyzer
			The cut scope	90-270℃	ASTM D86
Density	0.65-0.78kg/l	ASTM D1298
			Form	Hydrocarbon	GC-FID
Spark delay (IQT)	2-7ms	ASTM D6890-03
			Cetane value	25-75	ASTM D613-03a
Aromatic content	＜1.0wt％	ASTM D5186-99 ASTM D6591-00
			Sulphur content	＜1ppm wt	ASTM D5453
Oxygen level	＜5000ppm	GC-TCD

Spark delay is high pressure, the high temperature of the fuel good index of character of lighting a fire automatically, and can be relevant with the cut scope and the octane number of fuel, and this further relates to its chemical constitution.The condition of carrying out the spark delay measurement is at IQT ^TMIn, under 22.4 crust normal atmosphere and 565 ℃, carry out, this and HCCI fuel in hcci engine possibly the condition of experience be comparable, therefore, spark delay (ID) can be as the appropriate yardstick of measurement HCCI fuel ignition quality.This means that the time having the high fuel of firing tendency automatically in compression will have short spark delay (about 2-4ms), and the automatic igniting resistance (equaling higher octane spark point igniting gasoline) with increase will have the spark delay (about 7-11ms) than length.

Because be exposed at fuel under the specified pressure and temperature condition of hcci engine combustion chamber, automatically igniting resistance and scale resistance are as broad as long, so these sulphur (S) and nitrogen (N) heteroatoms that exist in the HCCI fuel that is obtained by crude oil will serve as oxidation retarder, cause longer spark delay and lower automatic firing tendency.

FT fuel is actually sulfur-bearing not, has the nitrogenous compound of lower level, and in hcci engine the time, does not exist these naturally occurring antioxidants will have benefit the FT fuel applications.Be better than conventional oil aspect this trend that causes them under the HCCI condition, to light a fire automatically.

Process flow sheet

In Fig. 1, comprised general block schema.Process choice for all four class HCCI fuel shows with simple format.Summed up base conditioning in the following table 2 for these fuel and charging.

The general requirement that table 2 is handled for the FT charging

Processing step	Technology is described	Reference
			Cut	Air distillation	(1)
Hydrotreatment	Saturated saturated other hydroconversion reaction of hydrogen that contains the oxygen-containing hydrocarbon of water form of the hydrogen of olefinic double bond	US 6475375
			Hydrocracking	(major part is saturated saturated other hydroconversion reactions of hydrogen with oxygen-containing hydrocarbon of water form of hydrogen of paraffinic hydrocarbons olefinic double bond in the cracking of weight molecule	EP 1129155

(1) for this unit operation many reference is arranged.For example, referring to PASchweitzer, Handbook of Separation Techniques for ChemicalEngineers (McGraw-Hill, 1979) or RH Perry and Chilton, ChemicalEngineers ' Handbook (McGraw-Hill, 5 ^ThEdition, 1973).

The preparation of synthetic HCCI fuel element can realize according at least four kinds of technology settings.A kind of selection for concrete device is to implement to require the technology of extra site and market specifying information synthetic.

First group of HCCI fuel-be referred to herein as SR FT-can be prepared by in distillation unit 1, fractionating out the synthetic FT hydrocarbon flow 10 of lightweight.This fractionation unit of operation carry out to(for) the requirement product specification has obtained product group 11.

Second group of HCCI fuel-be referred to herein as SR HT FT-can by at first in hydrogenation unit 2 hydrogenation remove the synthetic FT hydrocarbon flow 10 of oxygen cause lightweight with saturated olefinic double bond with from oxidizing substance and obtain.Hydrogenation products is fractionated to required specification in fractionation unit 3 then, obtains product group 13.

The 3rd group of HCCI fuel-be referred to herein as HX FT-can obtain lighter saturated hydrocarbons by hydrocracking in hydrocracking unit 4 and obtain by overlapping into FT hydrocarbon flow 14.Product through the hydrogenation deterioration can obtain product group 16 through being fractionated to required specification in fractionation unit 5 then.

Prepare the 4th kind of HCCI fuel-be referred to herein as GTL (the GTL=gas phase is to liquid phase)-alternatives can be prepared by the product of above-mentioned hydrotreatment of direct blend and hydrocracking.In an optimal way, this can be undertaken by using conventional separation column unit 6, to obtain required specification, has obtained product group 18.

Can also by a shared conventional fractionator or after fractionation blended product 11 and 16, obtain synthetic HCCI fuel.

The by product that in all these method options, has non-HCCI hydrocarbon flow, promptly lighter or heavier product than related HCCI synthetic product.The former can be described as the hydrogen petroleum naphtha and the latter is described as the heavy gas oil materials flow.These can be used for fuel or non-fuel purposes.

All fuel of any group can be as the blend components of final HCCI fuel in next comfortable these four groups.

The emission behavior of synthetic FT HCCI fuel

Be that synthol is than conventional oil generation noxious emission still less for what people accepted extensively.This point repeatedly has been incorporated into known field-for example referring at San Antonio, texas, the National Petrochemical that hold in March, 2000; " benefit that the Fischer-Tropsch synthetic crude is handled and its product and conventional oil the are merged "-paper AM-00-51 that provides among the RefinersAssociation Meeting.This document has been mentioned FT petroleum naphtha and FT diesel oil.

The typical quality of synthetic FT HCCI fuel

Table 3 contains by the typical quality of the synthetic FT HCCI fuel of above-mentioned preparation and meets selected requirement.Table 3 has shown the contrast of HT SR FT and crude oil derived fuel.

The typical quality of the synthetic FT HCCI fuel of table 3

	Required scope		SR FT			HT SR FT
									C 7-C 9	C 7-C 14	C 10-C 14	C 7-C 9	C 7-C 14	C 10- C 14
			The cut scope	90-270	℃	103- 183	103- 251	164- 251							90- 160	90- 254	165- 254
Density	0.65-0.78	kg/l							0.67	0.71	0.76	0.71	0.74	0.76
			Form
The ■ n-paraffin		wt％							52.5	63.1	68.4	94.6	94.9	95.1
			The ■ isoparaffin		wt％	0.4	1.6	2.2							5.4	5.1	4.9
■ alkene		wt％							38.5	26.5	20.5	0	0	0
			The ■ oxygenant		wt％	8.6	8.8	8.9							0	0	0
Spark delay (IQT TM)	2-7	ms							3.34	2.79	2.60	3.44	2.74	2.54
			Cetane value	30-70		60	75	83							58	77	86
Aromatic content	＜1.0％	wt％							＜0.1	＜0.1	＜0.1	＜0.1	＜0.1	＜0.1
			Sulphur content	＜1ppm	wt	＜1	＜1	＜1							＜1	＜1	＜1
Oxygen level	＜5000	ppm (wt)							700	2000	2150	＜80	＜80	＜80

	Required scope		HX			GTL
									C 7-C 9	C 7-C 14	C 10- C 14	C 7-C 9	C 7-C 14	C 10- C 14
			The cut scope	90-270	℃	80-163	80-250	135- 250							90-163	90-250	155- 250
Density	0.65-0.78	kg/l							0.68	0.72	0.74	0.69	0.72	0.75
			Composition
The ■ n-paraffin		wt％							46.0	30.7	26.6	57.5	41.0	38.0
			The ■ isoparaffin		wt％	54.0	69.3	73.4							42.5	59.0	62.0
■ alkene		wt％							0	0	0	0	0	0
			The ■ oxygenant		wt％	0	0	0							0	0	0
Spark delay (IQT TM)	2-7	ms							4.92	4.06	3.50	4.55	3.34	3.08
			Cetane value	30-70		41	49	57							44	60	66
Aromatic content	＜1.0％	wt％							＜0.1	＜0.1	＜0.1	＜0.1	＜0.1	＜0.1
			Sulphur content	＜1ppm	wt	＜1	＜1	＜1							＜1	＜1	＜1
Oxygen level	＜5000	ppm (wt)							＜80	＜80	＜80	＜80	＜80	＜80

Table 4: the synthetic FT fuel that is used for HCCI fuel of equivalent and the contrast of crude oil derived fuel

	Required scope		HT SR FT			Crude Derived Fuels
									C 7-C 9	C 7- C 14	C 10- C 14	C 7-C 9	C 7-C 14	C 10-C 14
			The cut scope	90-270	℃	90- 160	90- 254	165- 245							80-159	80-257	151-257
Density	0.65-0.78	kg/l							0.71	0.74	0.76	0.7329	0.7715	0.7961
			Composition
The ■ n-paraffin		wt％							94.6	94.9	95.1	28.2	23.8	24.7
			The ■ isoparaffin		wt％	5.4	5.1	4.9							32.8	53.0	55.3
■ alkene		wt％							0	0	0	0.4	0.4	0.5
			The ■ oxygenant		wt％	0	0	0							0	0	0
■ aromatics		wt％							0	0	0	10.3	14.2	18
			The ■ petroleum naphtha		wt％	0	0	0							28.3	8.6	1.5
Spark delay (IQT TM)	2-7	ms							3.44	2.74	2.54	6.17	5.22	4.79
			Cetane value	30-70		58	77	86							34.1	39.0	42.0
Sulphur content	＜1	ppm wt							＜1	＜1	＜1	50	50	50

Below table 5 shown the embodiment of quality characteristic of the blend of C7-C9 GTL HCCI fuel and equivalent petroleum fractions.The benefit that contains synthetic FT fuel in conventional blend is quite obvious.

The quality of the blend of table 5:C7-C9 GTL HCCI fuel and equivalent petroleum fractions

		The GTL fuel content
							0％	25％	50％	75％	100％
		Density	kg/l	0.733	0.722	0.711						0.700	0.690
Composition
		N-paraffin	wt％	28.2	35.4	42.8						50.1	57.5
Isoparaffin	wt％						32.8	35.1	37.6	40.0	42.5
		Alkene	wt％	0.4	0.3	0.2						0.1	0.0
Oxygenant	wt％						0.0	0.0	0.0	0.0	0.0
		Aromatics	wt％	10.3	7.8	5.2						2.6	0.0
Petroleum naphtha	wt％						28.3	21.3	14.2	7.1	0.0
		Total amount	wt％	100.0	99.9	100.0						99.9	100.0
Spark delay (IQT TM)	ms						6.17	5.75	5.22	4.75	4.55
		Cetane value		34.1	36.0	39.1						41.9	44.0
Sulphur content	ppm						50	38	25	13	＜1

Claims (22)

1. HCCI fuel or fuel element, this fuel comprise and comprise n-paraffin and the isoparaffin with 7-14 carbon atom at least, and according to ASTM D6890, this fuel has the spark delay that is lower than 7ms.

2. the fuel of claim 1, this fuel comprise the aromatic substance that is lower than 1 weight % and can ignore the sulphur of level.

3. each fuel in the aforementioned claim, this fuel has the spark delay that is lower than 5ms.

4. each fuel in the aforementioned claim, this fuel has the spark delay of 2-5ms.

5. each fuel in the aforementioned claim, wherein the quality % of n-paraffin surpasses the content of any other one-component in the fuel.

6. each fuel in the aforementioned claim, wherein the quality % of n-paraffin surpasses 25 quality % of this fuel.

7. each fuel in the aforementioned claim, wherein the quality % of n-paraffin surpasses 50 quality % of this fuel.

8. each fuel in the aforementioned claim, wherein the quality % of n-paraffin surpasses 80 quality % of this fuel.

9. each fuel in the aforementioned claim, wherein the quality % of n-paraffin surpasses 95 quality % of this fuel.

10. each fuel in the aforementioned claim, wherein n-paraffin is the n-paraffin that derives from Fischer-Tropsch (FT) reaction.

11. each fuel in the aforementioned claim, wherein isoparaffin is the isoparaffin that derives from fischer-tropsch reaction.

12. each fuel in the aforementioned claim, this fuel comprise following one or more: alkene, lubrication modifier and oxygenant.

13. each fuel among the claim 1-11, this fuel are substantially free of heteroatoms for example nitrogen, sulphur and oxygen.

14. each fuel in the aforementioned claim, this fuel have 90 ℃-270 ℃ ASTM D80 cut.

15. among the claim 1-14 each HCCI fuel or fuel element as with the purposes of the blend components of traditional fuel.

16. be used to prepare the method for HCCI fuel or fuel element, this fuel or fuel element comprise n-paraffin and isoparaffin at least, this fuel has the spark delay that is lower than 7ms, and described technology comprises and is selected from following one or more steps:

A) the condensate fraction or derivatives thereof of hydrotreatment at least a portion Fischer-Tropsch (FT) building-up reactions product;

B) hydrogenation transforms the wax slop or derivatives thereof of FT synthetic product;

C) one or more hydrogenation conversion cuts through the condensate fraction and the step b) of the step a) of hydrotreatment of fractionation in single unit or separate units are to obtain ideal HCCI fuel or fuel fraction; And

D) randomly, with the two kinds or more of described components of required ratio blend, to obtain ideal HCCI fuel from step c).

17. the method for claim 16, it is to be undertaken by hydrocracking that hydrogenation wherein transforms.

18. the method for claim 16 or 17, wherein the blend of step d) is with 1: 99 to 99: 1 the volume blend ratio blend FT condensation derivative and the FT wax derivative of hydrogenation conversion.

19. each method among the claim 16-18, wherein the fuel by this prepared is the fuel in each in claim 1-14.

20. the HCCI fuel or the fuel element of claim 1, basically as described herein and the record.

21. the technology of claim 16 is basically as describing herein and putting down in writing.

22. describe as this paper basically and novel HCCI fuel or fuel element, the perhaps novel method of record.

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