Zhang-2008-Ultra-stability of gas hydrates at
Chemical Engineering Science63(2008)2066–
2074
https://www.docsj.com/doc/1710015954.html,/locate/ces
Ultra-stability of gas hydrates at1atm and268.2K
Guochang Zhang,Rudy E.Rogers?
Swalm School of Chemical Engineering,Mississippi State University,Mississippi State,MS39762,USA
Received17August2007;received in revised form19December2007;accepted2January2008
Available online17January2008
Abstract
This paper details creation of methane sI hydrates that are much more stable at1atm and268.2K than any previously reported.Extraordinarily stable natural gas sII hydrates at1atm and268.2–270.2K are reported for the?rst time.Test innovations that achieved ultra-stabilities give insight into hydrate self-preservation mechanisms.Water–surfactant liquid solutions were used to nucleate hydrate crystals that adsorbed as extremely small particles on surfaces of high thermal conductivity.The small hydrate particles packed and consolidated symmetrically upon Al or Cu cylindrical surfaces,minimizing internal void spaces and fractures in the accumulated250–400g hydrate mass.Resulting hydrate stability window is268.2–270.2K at1atm.Methane sI,as well as natural gas sII,hydrates exhibit only minimal decomposition upon reducing con?ning system pressure to1atm in the268.2–270.2K stability window.Total gas that evolved after24h at1atm in the stability window typically amounted to less than0.5%of originally stored gas,and this ultra-stability was shown to persist when the test was allowed to run 256h before terminating.The entire methane sI or natural gas sII hydrate mass remains stable during pressure reduction to1atm,whereas previous reports de?ned hydrate anomalous stability for only about50%of fractional hydrate remnants.
?2008Elsevier Ltd.All rights reserved.
Keywords:Energy;Nucleation;Particle formation;Surfactant;Hydrates;Gases
1.Introduction
1.1.Discovery of hydrate anomalous stability
For equilibrium stability of methane gas hydrates at at-mospheric pressure,temperature must be lowered to193K. However,if the polycrystalline methane hydrates are formed on the surface of ice at high pressures,an anomalous stability for methane sI hydrates occurs when pressure is lowered to1atm within a temperature window between about245and270K (Stern et al.,2001,2002a,b,2004;Takeya et al.,2001).Circone and co-workers(2004)report that at temperatures above or below the anomalous stability envelope,sI methane hydrates decompose at rates of orders of magnitude greater than in the metastable window.Curiously,natural gas sII hydrates con-taining predominantly methane and forming under similar pro-cedures from ice precursor did not demonstrate the anomalous ?Corresponding author.Tel.:+16623255106;fax:+16623252482.
E-mail address:rogers@https://www.docsj.com/doc/1710015954.html,(Rudy E.Rogers).
0009-2509/$-see front matter?2008Elsevier Ltd.All rights reserved. doi:10.1016/j.ces.2008.01.008stability(Stern et al.,2002a,b).The anomalous stabilities are based on the remnant mass of hydrates after loss of up to50% of the original hydrates by decomposition.The hydrates that decompose are thought to help preserve the fraction remain-ing(Takeya et al.,2001).It should be noted that methane or natural gas hydrates decompose rapidly as temperatures are raised through the ice point—no matter the means of prepara-tion(Stern et al.,2001).
The ice precursor procedure for studying hydrate self-preservation reported by Circone et al.(2004)begins with ice particles of180.250 m diameter packed in a cylindrical core. When subjected to slow temperature increases,outer surfaces of discrete ice particles liquefy,and this periphery melt re-acts with cold methane pressurized to27–30MPa to form a shell of gas hydrate around the remaining ice.After the hy-drate rind surrounds the ice,subsequent reaction and reaction rate of the interior ice is limited by the diffusion of methane through hydrate(Stern et al.,1996).The pressurized condi-tion is maintained for12–15h until all ice converts to about 30g hydrates in a cylindrical core2.5cm diameter by9.5cm long.After conversion of ice,resulting hydrate mass exhibits
G.Zhang,R.E.Rogers/Chemical Engineering Science63(2008)2066–20742067
approximately29%porosity.Upon compaction,the hydrate
cores become substantially shortened as the pores collapse
(Durham et al.,2003).The resulting polycrystalline methane
hydrate particles are approximately250.300 m diameter
(Circone et al.,2004).These gas hydrates of CH4·5.89H2O form in a gas-rich environment where free gas is in excess.
Circone et al.(2004)relate that cryogenic SEM analyses
of250.300 diameter hydrate particles,generated from ice
in which hydrates started forming on the outer surface of the
melting ice particles and proceeded inward,showed frequent
hollow shells of hydrate.The shells indicate sheaths of hydrate
initially encasing unreacted core ice or liquid;micro-fracturing
of the shell possibly occurred upon phase change expansion.
Those observations check with Davidson et al.(1986),who
postulated anomalous hydrate stability as resulting when an ice
shell,created from partial hydrate decomposition,surrounds
remnant hydrate with enough strength to withstand decompo-
sition pressures.Due to weakening of the ice shield,or due to
pressure buildup in the core,fracturing of the shell presaged
more rapid decomposition.The ice melt exiting from the core
apparently annealed fractures and melded surrounding particles
of the hydrate mass.In the belief that some ice may remain
unreacted in the core,Stern et al.(2004)suggest the need for
beginning with small grain-size ice in order to avoid the center
cavity surrounded by a hydrate shell observed by their cryo-
genic SEM.Smaller ice grain sizes present greater gas/ice in-
terfacial areas per unit volume of the ice and thus more rapid
hydrate formation(Staykova et al.,2003).This relationship of
larger interfacial areas promoting hydrate formation rates hold
for other surfaces,such as the renewed water–gas interfacial
area of a stirred system(Vysniauskas and Bishnoi,1983).
In order to study the self-preservation phenomenon,Takeya
et al.(2001)started with?nely ground ice and formed hy-
drate particles of about20.50 m mean diameter.Also,Kuhs
et al.(2000)used powdered ice ground in liquid nitrogen to a
few hundred m diameter to form gas hydrates for anomalous
stability studies.Hydrates began forming as a?lm around an
ice particle and proceeded to slowly cover the ice surface and
then grew inwardly as gas and water diffused through hydrate
capillaries.For the larger initial ice particles,unconverted ice
sometimes remained in the center—surrounded by gas hydrate.
Cryo-SEM studies showed the hydrates composed of sponge-
like networks of40–400nm diameter pores?lled with gas.The
pores perhaps occupied15–20%of the hydrate volume.The el-
liptical and branched pore networks were closed and inaccessi-
ble to water for further reaction;some channels with diameters
of a few m formed in the hydrate matrix(Kuhs et al.,2004).
Not only hydrates formed by the ice precursor method,but
hydrates formed as a?lm on liquid water surfaces exhibit
the sponge-like network of small pores(Salamatin and Kuhs,
2002).Shimada et al.(2005)formed methane hydrates in a
stirred,distilled water system;small hydrate particles?rst
formed but then agglomerated to spherical particles of about
20 m diameter,and these particles formed a roughly porous
network.
Therefore,in the ice precursor method of forming hydrates,
two nonconformities create decomposition surfaces that con-tribute to hydrate instability in the anomalous stability domain: porous structures between hydrate granules and voids within hydrate particles from unreacted ice.
Currier and Schulson(1982)report a decrease in fracture tensile strength of polycrystalline ice spheres as the diameter increases,as given by the following equation:
f= i+kD?0.50.(1) Here f is the fracture tensile strength(MPa); i is the exper-imental constant(0.60MPa);D is the ice grain diameter(m), and k is an experimental constant(0.02MPa m1/2).
In aggregates of ice grains,brittle micro-fractures propor-tional to the diameter of the grains of ice govern the magnitude of the aggregate’s tensile strength at a temperature approxi-mately0.96of the ice melting point.It is proposed by Schulson (1979)that as ice grain sizes decrease,a critically small diam-eter may be attained where ductile properties of the aggregate ice under tension prevail over brittle properties.
One surmises that the stability afforded by a given ice-shield thickness created around methane hydrate varies with the parti-cle size.The wall thickness to give stability to a spherical par-ticle pressurized internally is given by the following equation (Kreith,1997):
t=
pD
4 f
.(2)
Here,t is the required minimum wall thickness to maintain an internal pressure p in a sphere of diameter D; f is the allowable stress in the wall material.
Wall thickness is proportional to the diameter of the spherical particle.Assuming that hydrate equilibrium pressures prevail inside an ice-coated sphere,one may use Eqs.(1)and(2)to compare stabilities of different particle sizes.
If fractures are approximated as cylindrical shapes,then wall thicknesses of these fractures must be twice those of spheri-cal voids to remain stable.Therefore,fractures emanating from voids or high stress points within the mass during hydrate for-mation or subsequent storage create a weakening of the hydrate structure to internal pressures.Currier and Schulson(1982) found that larger ice crystals,as compared to the smaller crys-tals,promote fracturing with longer fractures when aggregates are subjected to tensile stress.
The mechanical strength of methane gas hydrate,if it has no signi?cant ice or water impurities,exceeds hexagonal water ice strength by a factor of40(Durham et al.,2003).Therefore,in a hydrate mass,small voids surrounded by hydrates instead of ice would afford greatest stability.
1.2.Anomalous stability extent at1atm:ice procedure
Fifty percent or more of methane sI gas hydrates decompose when system pressure is reduced either slowly or rapidly to 1atm while maintaining temperatures within a245–270K en-velope.The50%or less hydrate remnant then exhibits1atm anomalous stability.Circone et al.(2004)reported the50% methane hydrate remnant was stable for several weeks,while
2068G.Zhang,R.E.Rogers/Chemical Engineering Science63(2008)2066–2074
Ershov and Yakushev(1992)reported<10%of an original methane hydrate mass remaining stable for more than a year.
1.3.Mechanism of anomalous stability:ice procedure
Gas-hydrate thermal conductivity is also much lower than that of ice(Waite et al.,2002).
As hydrates decompose,the cooling effect may solidify wa-ter liberated from the hydrate structure.Possibly,an ice Ih ?lm envelops the hydrate particle after partial dissociation and thereafter this ice serves as a barrier to gas diffusion(Yakushev and Istomin,1992;Davidson et al.,1986).If the?lm is strong enough,localized pressure buildup in the interior of particles could reach stable equilibrium pressures(Davidson et al.,1986; Shimada et al.,2005).However,the ice?lm may not have suf-?cient mechanical strength to support a high equilibrium pres-sure.The diffusion coef?cient for gas through ice is much less than the value observed during decomposition,and the data more closely describe diffusion between granules of hydrate (Takeya et al.,2001).Ice coatings of remnant hydrate may be a secondary cause of hydrate stability,but many questions re-main to explain the hydrate anomalous stability mechanism.
1.4.Objectives of the research
The subject research was undertaken to improve and possibly resolve unexplained properties of gas hydrate anomalous stabil-ity at1atm.The goals were the following:(1)Form ultra-stable natural gas sII hydrates for the?rst time,(2)form methane sI and natural gas sII hydrates exhibiting long-term ultra-stability at1atm,(3)achieve ultra-stability in a larger fraction of the initial hydrate mass,and(4)explore a path other than the ice-genesis process that could potentially produce hydrates rapidly on a larger scale.
The approach was based upon our previous studies of forming gas hydrates from anionic surfactant solutions.In a surfactant–water solution pressurized by hydrocarbon gas, the surfactant becomes hydrate nucleation centers subsurface of the water by assimilating hydrocarbon gas solute around the hydrophobic moieties and structured water around the hy-drophilic moieties.This nucleation process has been observed to initiate subsurface in the water in a water-rich,gas-lean environment.The surfactant/hydrate crystals adsorb on metal surfaces at the gas/water interface,so that hydrates collect uniformly on the metal walls of a cylindrical test cell in a manner thought to be a porous packing of extremely small hy-drate particles where gas can permeate the packing to further react with interstitial water.The hydrates grow radially and symmetrically on the metal walls(Zhong and Rogers,2000).
2.Experimental section
Methane hydrate stabilities were measured by the percent-ages of gas evolved for the?rst12min after a5s test cell de-pressurization,by the percentages of gas evolved during the ?rst24h,and by longer arbitrarily determined test periods.Percentages were based on the total gas occluded in hydrates before depressurization,as determined by a wet-test meter that was used to measure gas volumes evolved.
2.1.General formation procedure
The hydrates formed inside a500cm3stainless steel Parr test cell in the presence of a non-stirred water solution of sodium dodecyl sulfate(SDS).In the presence of SDS,methane or natural gas hydrates adsorb on the metal at the gas/water interface and build radially.For additional surface area an aluminum tube,copper tube,or solid copper cylinder was placed upright in the center of the test cell.Solutions with SDS concentrations between300and1000ppm were added in quantities of250–350ml.The cell was pressurized with hy-drocarbon gas between3.84and4.52MPa and submerged in a constant temperature bath of273.7K.After forming gas hydrates,the cell contents were further cooled to268.2K. Thereafter,upon depressurization to1atm in5s,gas hydrates proved to be ultra-stable below270.2K.To estimate the total amount of gases occluded in gas hydrates,gas hydrates were heated above273.2K to decompose all hydrates after moni-toring gas evolution during the ultra-stable period.The gases from the decomposition were measured with a wet-test meter to within±1ml of gas evolved.
Variations in the procedure,depending on whether natural gas sII or methane sI hydrates were being formed,were neces-sary to achieve ultra-stability.
2.2.Procedure(1)to form methane sI hydrates
In preparation of methane hydrates,a2.54cm diameter Al tube of13.97cm length was placed upright in the center of the 7.62cm diameter by15.24cm length test cell of stainless steel. Methane hydrates were generated from300ml of300ppm SDS distilled water solution at273.7K and under constant pressure of3.84MPa methane.After formation,hydrates were cooled to 268.2K and then depressurized to1atm in5s.The methane gas evolved was checked at268.2K by means of a wet-test meter.
2.3.Procedure(2)to form natural gas sII hydrates
During the formation of natural gas hydrates,a2.54cm diameter Cu tube of13.97cm length,or a solid copper cylin-der of the same dimensions,was placed upright in the center of the test cell.Natural gas hydrates were created in two steps. In the?rst step,250ml of600or1000ppm SDS in distilled water solution was added to the test cell,and then hydrates were produced at273.7K under constant pressure of3.84MPa of natural gas consisting of90%methane,6%ethane,and4% propane.In the second step,the system was cooled to271.7K at constant3.84MPa.After completing water conversion to hy-drates,the hydrates were cooled to268.2K and then depres-surized to1atm in5s.The gases that evolved as a function of time were measured with a wet-test meter.
G.Zhang,R.E.Rogers /Chemical Engineering Science 63(2008)2066–20742069
2.4.Procedure (3)to form natural gas sII hydrates
A 2.54cm diameter copper tube of 13.97cm length was placed upright in the center of the test cell.Then,250ml of 600or 1000ppm SDS solution was added.At ?rst,natural gas hydrates were created under constant temperature of 273.7K and constant pressure of 3.84MPa.Second,the pressure inside the test cell was increased to 4.53MPa to react any residual free water into hydrates.When hydrate formation was ?nished,SDS solution of up to 100ml was injected into the test cell to form gas hydrates again at 273.7K and 4.53MPa.After com-pletion,hydrates were cooled to 268.2K and then depressur-ized to 1atm in 5s.The gases evolved as a function of time were measured with a wet-test meter to within ±1ml.3.Results and discussion 3.1.Methane sI hydrate stability
Data for the ultra-stable methane hydrates are given in Table 1.Each of the two data sets in Table 1was from an indi-vidual run at a different time.Likewise,in Tables 2and 3each group of experiments denoted by the roman numerals is re-peated as indicated by the subgroup of experiments.In Table 1the methane hydrates that were formed by the surfactant pro-cess at 273.7K and 3.84MPa had hydrate numbers of 6.4–6.7as determined from mass balances.When occluded gas vol-umes were converted to a standard temperature–pressure basis and compared to volumes of hydrates,volume-gas/volume-hydrate ratios were determined to be in the range 149.7–154.4.Dissociation was noted upon releasing pressure to 1atm.See Table 1.Only 0.003%of total occluded gases in the methane sI hydrates evolved during the ?rst 12min at 268.2K.
After 24h of dissociation at 1atm and 268.2K,the methane sI hydrates retained more than 99.5%of the originally stored gas.The extremely small decomposition of methane hydrates over 24h applies to all hydrate mass formed initially—not just to a remnant after depressurization.When the tests were arbi-trarily terminated at the 24h point,ultra-stability had not deteri-orated.The ultra-stability may be explained by unique hydrate formation characteristics of the surfactant process.
Table 1
Methane hydrate stability at 268.2K and 1-atm:Procedure (1)Run
V wl (ml)a
C sds (ppm)b
12min Dissociation at 1atm and 268.2K 24h Dissociation c at 1atm and 268.2K V total (±1ml)f N e d V g/gh e
V olume gas
evolved (±1ml)
%Hydrates decomposed V olume gas
evolved (±1ml)%Hydrates decomposed I
130030023×10?3290480×10?360,061 6.7149.72
300
300
2
3×10?3
3
5×10?3
62,174 6.4154.4
a V olume
of distilled water–surfactant solution added to the test cell,ml.
b Concentration
of SDS in distilled water,ppm.
c Monitoring stopped;stability goes beyon
d this time.
d Hydrat
e number,mole number ratio o
f water to gas occluded in hydrates.e V olumes of gases occluded per volume of hydrates,STP.
f Total volume of gas recovered from the gas hydrates (measured by wet-test meter at 293.2K and 1atm).
The ultra-stabilities of the methane hydrates formed from the surfactant process were achieved because of properties im-parted to the hydrate mass from that process.
Hydrate decomposition occurs on exposed surfaces,and the rate of decomposition increases with gas/solid interfacial sur-face area.Therefore,fractures must especially be avoided be-cause of their surface area increase and their weaker structure in containing pressurized gas compared to spherical voids.In our surfactant system,it is believed that approximately the entire water mass in the particle had been converted to hy-drates.First,with anionic surfactant as nuclei,hydrates initiate around the gas associated with the hydrophobic moiety,and the hydrate crystal grows from there outwardly.Second,negligible unreacted water remained in the particle interior because the particle growth occurred where heats of formation were rapidly dissipated in a high heat transfer rate medium—?rst in the sub-surface of the water and then on a conductive metal surface at the water–gas interface.Therefore,the small,nearly spheri-cal particles were composed of hydrates throughout,and there was no phase change within the cores to fracture surrounding material.
Insigni?cant ice rind formed around the hydrate particles upon depressurization simply because the hydrate decomposi-tion itself was miniscule.Therefore,the stability of the basic hydrate particle was not due to an ice “rind”.
If we assume the hydrate mass is porous as Kuhs et al.(2004)found in most hydrates,the surrounding hydrate walls of the pores must have been stable.We believe this to have occurred because:(1)Pores were extremely small,(2)surrounding hy-drates afforded greater strength than ice,(3)pores were not interconnected.
We reason that the basic hydrate particles were especially small,giving close packing after being adsorbed on the metal surfaces and thus minimizing sizes of inter-particle pore spaces.Also,rapid solidi?cation as hydrate particles adsorbed on the cold,conductive metal surfaces at the water–gas interface cre-ated a porous network where interstitial water was accessible and reacted to near completion with surrounding,pressurized hydrocarbon gases that diffused through the network.
Consider in more detail the hypothesis of very small hy-drate particles.Hydrates nucleated around gas absorbed on the
2070G.Zhang,R.E.Rogers/Chemical Engineering Science63(2008)2066–2074 Table2
Natural gas hydrate ultra-stability at268.2K and1atm:Procedure(2)
Run V wl(ml)a C sds(ppm)b12min Dissociation at
1atm and268.2K Long-term dissociation c
at1atm and268.2K
V total(±1ml)d T D(h)e N e f V g/gh g
V olume gas evolved(±1ml)%Hydrates
decomposed
V olume gas
evolved(±1ml)
%Hydrates
decomposed
I1250100023×10?392×10?257,28724 5.8171.3 2250100012×10?324×10?354,87524 6.1165.1 3250100012×10?312×10?354,59024 6.1164.4 4h25010003673×10?37916×10?249,620248.1151.3 525010003053×10?35089×10?356,232247.1168.6
II125060012×10?347×10?356,39085 5.9169.0 22506002849×10?34274×10?356,62948 5.9169.6
III130010001321×10?33048×10?362,18824 6.4157.2 230010006911×10?2122200×10?361,01725.3 6.6154.6
a V olume of distilled water–surfactant solution added to the test cell,ml.
b Concentration of SDS in distilled water,ppm.
c Monitoring stopped;stability goes beyon
d this time.
d Total volum
e o
f gas recovered from the gas hydrates(measured by wet-test meter at293.2K and1atm).
e Time o
f hydrate dissociation at1atm,268.2K.Hydrates remain stable at experiment termination.
f Hydrate number,mole number ratio of water to gas occluded in hydrates.
g V olumes of gases occluded per volume of hydrates,STP.
h Copper solid cylinder.
Table3
Natural gas hydrate stability at268.2K and1atm:Procedure(3)
Run V wl(ml)a V inj(ml)b C sds(ppm)c12min Dissociation at
1atm and268.2K Long-term dissociation d
at1atm and268K
V total(±1ml)e T D(h)f N e g V g/gh h
V olume gas evolved(±1ml)%Hydrates
decomposed
V olume gas
evolved(±1ml)
%Hydrates
decomposed
I1150100100012×10?324×10?345,086247.4139.2 II1i180100100012×10?31940×10?347,3102567.9131.4 III12501001000392600×10?3524800×10?365,608487.1144.0 IV1250806009717×10?2114800×10?356,000247.9131.9 225056002137×10?33460×10?356,67024 6.0166.9 3250406006211×10?27013×10?255,614 6.4 6.9146.9
a V olume of distilled water–surfactant solution added to the test cell,ml.
b V olume of distilled water–surfactant solution injected to the test cell,ml.
c Concentration of SDS in distille
d water,ppm.
d Monitoring stopped;stability goes beyond this time.
e Total volume o
f gas recovered from the gas hydrates(measured by wet-test meter at293.2K and1atm).
f Time of hydrate dissociation at1atm,268.2K.Hydrates remain stable at experiment termination.
g Hydrate number,mole number ratio of water to gas occluded in hydrates.
h V olumes of gases occluded per volume of hydrates,STP.
i Ultra-stability achieved over dissociation temperature range of268.2–270.2K.
hydrophobic alkyl tails,or possibly micelles,of the surfactant in the water subsurface;crystals buoyed to the water surface, and adsorbed on metal at the water–gas interface.Growths of the embryo crystals in this gas-lean environment of the water subsurface were limited by the unavailability of hydrocarbon gas.A second limitation to crystal growth after nucleation in the water’s subsurface is thought to be physical particle segregation due to orientations of the12-carbon alkyl surfactant tails on the developing crystal surfaces.A third limiting factor to hydrate particle growth is thought to be that the crystals developed similar surface charges as they moved separately to the water’s surface;the like charges of the surfactant anions attached to the crystals are thought to have helped prevent agglomeration. During early experiments with surfactant solutions to gen-erate gas hydrates,Zhong and Rogers(2000)observed and ?lmed the?occulation of small hydrate particles that collected
G.Zhang,R.E.Rogers /Chemical Engineering Science 63(2008)2066–20742071
4.543.5
32.521.5
10.50
05001000150020002500300035004000
4500
Time Mi u nte
300295290
285280
275
270265T e m p e r a t u r e K
P r e s s u r e M P a
Hydrate formation
P T Depress u rize to 1 atm in 5 sec.
Fig.1.Formation of ultra-stable methane gas hydrates in the surfactant process.Hydrates were formed according to Procedure (1).
at metal surfaces of the gas–water interface after initiating in the water’s subsurface;the cloud of particles compacted on the conductive metal surfaces as the static electrical charges dissi-pated.We believe the electrical charges help segregate hydrate crystals and prevent agglomeration until the hydrate particles are immobilized on the cold metal surfaces.
In the temperature range of our stability tests,development of internal stresses from dissimilar materials (phase change,thermal expansion,or thermal conductivity differences)that might have led to fractures was minimized because hydrates are thought to have been uniformly and singularly formed through-out the mass.Also,the hydrates were collected on cylindrical metal surfaces and their symmetrical growth minimized stress points within the mass.
In Fig.1is a pressure versus temperature trace for Procedure (1)to establish methane sI hydrates.The temperature trace shows cool down of the system from an initial 293.2–273.7K.Shortly thereafter,hydrates formed rapidly as seen by the peaks for rapid temperature rise.After reducing system temperature to 268.2K and depressurization to 1atm in 5s,methane hydrates exhibited ultra-stability.
3.2.Natural gas sII hydrate stability
This study reports the ?rst ultra-stable generation of natural gas sII hydrates.In Fig.2are the pressure–temperature–time traces for the formation of ultra-stable natural gas sII hydrates.Higher rates of heat transfer at the hydrate formation site are helpful to achieve ultra-stability of natural gas sII hydrates as compared to methane sI hydrates.In the surfactant process,nat-ural gas sII ultra-stability results when hydrates adsorb and form on a cylindrical copper conductor.Although methane sI hy-drates demonstrated ultra-stability when formed on aluminum,the ultra-stability did not occur with sII natural gas hydrates
when they formed on an aluminum cylinder under these hy-drate formation conditions.Thermal conductivity of aluminum is 247W/(m K)whereas the value for copper is 398W/(m K).Thermal conductivity of the copper is 61%greater than alu-minum (Callister,1994).
A summary of ultra-stable natural gas hydrates formed by Procedure (2)in separate laboratory tests is presented in Table 2.Tests were stopped after arbitrary periods of hydrates being subjected to conditions of 1atm and 268.2K,and in each case the hydrates were maintaining ultra-stability at the time of ter-minating the test.One test was carried to 85h and had exhibited only 0.007%decomposition at termination.Another test was taken to 48h,at which time 0.074%of the original hydrates had decomposed.A majority of tests were extended to about 24h before terminating;all of these tests gave less than 0.16%hydrate decomposition up to the 24h.After remaining at 1atm and 268.2K for 24h,data subset 5of data set I in Table 2showed only 0.089%dissociation,whereupon the temperature was raised to 272.2K and hydrates started to decompose af-ter 2h.The gas to hydrate volume ratios in the ultra-stable natural gas hydrates ranged from 151.3–171.3(gas volume,STP/hydrate volume).
In Table 3are summarized tests under Procedure (3)that also gave ultra-stable natural gas hydrates.A slightly lower gas to hydrate volume of 131.4–166.9(gas volume,standard temperature and pressure/hydrate volume)resulted.The time that the hydrate mass was subjected to 1atm pressure and 268.2–270.2K was extended with ultra-stability to 256h (10.7days)in data set 2of Table 3.After 256h,only 0.040%of the original natural gas hydrates had decomposed;at the arbitrarily chosen 256h terminal point,the hydrates remained ultra-stable.In Fig.3are pressure and temperature traces for the forma-tion of ultra-stable natural gas sII hydrates formed by using Procedure (3)experimental procedure.
2072G.Zhang,R.E.Rogers /Chemical Engineering Science 63(2008)2066–2074
4.543.532.521.5
10.500
200
400
600
80010001200
Time Min u te
P r e s s u r e M P a
265
270
275280285290
295T e m p e r a t u r e K T P
1st hydrate formation 2nd
hydrate formation
Depressize to 1 atm in 5 sec
Fig.2.Natural gas sII ultra-stable hydrates formation.Hydrates formed by Procedure (2).Natural gas composed of 90/6/4methane/ethane/propane.
54.543.532.521.510.50
0500100015002000
2500
Time Min u te
P r e s s u r e M P a
295290285280275270265T e m p e r a t u r e K Depressize to 1 atm in 5 sec.
P T
Hy d r a te form a tion
Hy d r a te form a tion
Inject SDS sol’n a n d hy d r a te form a tion
Fig.3.Formation of natural gas sII ultra-stable hydrates.Hydrates formed by Procedure (3).
3.3.Factors promoting ultra-stability in surfactant process The 1atm ultra-stability of gas hydrates reported in this work achieved those stabilities between 268.2and 270.2K.This moves the envelope of ultra-stability to a slightly warmer max-imum temperature than previously reported.
Small hydrate particle sizes created by the surfactant pro-cess,high heat transfer rates,ef?cient mass transfer,minimum exterior surface area of the hydrate mass,and hydrate symme-try with fewer fractures characterize the surfactant process that achieved hydrate ultra-stability.All of these factors are believed to play important parts in hydrate ultra-stability.
3.3.1.Small hydrate particle sizes in surfactant process
When small gas hydrate particles form in the surfactant pro-cess,several factors enhance hydrate ultra-stability:(1)Surface areas of hydrate particles are high relative to volume,boosting heat and mass transfer rates.(2)Because of higher heat and mass transfer rates,complete reaction occurs throughout the hydrate particle,and negligible unreacted phase remains in the particle center.Hydrates grow outwardly from the crystal nu-clei in a gas-lean environment.That is,hydrocarbon gases ac-cumulate at nucleation centers,which are individual surfactant
molecules or molecular associations as micelles.This contrasts with the precursor-ice method where hydrate formation begins at outer boundaries of ice particles in a gas-rich environment.(3)Hydrate interstitial voids and sizes are minimal because of close packing of the small particles.Permeability of the stacked particles allows gas to access and react with interstitial water of the packing.(4)Electrostatic charges develop as hydrate crys-tals with attached surfactant anions move upward through the water to the metal adsorption sites,repelling adjacent particles,and hindering growth by agglomeration;because growth is in a gas-lean environment,particle sizes are additionally limited.Also,alkyl 12carbon chains of the SDS may physically hinder agglomeration and help limit particle sizes.
Although hydrate particle diameters formed in the anionic surfactant process could not be measured,very small diameters are indicated.Film shows individual crystals initiate subsurface of the surfactant–water solution,buoy to the solution surface,?occulate,and adsorb on metal surfaces at the gas–water in-terface.Charges on the ?occulant’s small particles dissipate at the conductive metal surface,and the particles compact into porous packings permeable to the pressurizing gas.
To achieve hydrate stability in the ice-to-hydrate process,Stern et al.(2004)alluded to high surface-to-volume ratios of
G.Zhang,R.E.Rogers/Chemical Engineering Science63(2008)2066–20742073
reacting ice grains and small grain sizes minimizing unreacted core volumes.It is believed that the surfactant process greatly enhances these desired attributes.If small voids are present throughout the hydrate mass formed in the surfactant process, the voids are thought to be small enough so that surrounding hydrates contain their equilibrium pressure.For example,if Eqs.(1)and(2)are used in tandem,it is determined that a 250 m diameter polycrystalline sphere requires a93 m thick ice coating to contain equilibrium methane sI hydrate pressures at273.7K,but a1 m diameter sphere would only require an 0.03 m thick shell to contain the equilibrium pressure.In the example,if hydrate was the surrounding material rather than ice,the strength could be as much as40times greater.
3.3.2.High heat transfer rates
When forming the ultra-stable gas hydrates from surfactant solutions,high heat transfer rates of metal surfaces help assure only a hydrate phase throughout the collected mass.The small particles collect on metal surface where interstitial water of the packing react to hydrates.
In the case of ultra-stable methane sI gas hydrates formed by Procedure(1)on a vertical aluminum cylinder extending above the water/gas interface,latent energies of formation were quickly removed by conduction,promoting more complete con-version of interstitial water solution to hydrates.Ultra-stability of natural gas sII hydrates could only be achieved when hy-drates were formed on the more conductive copper surfaces. Since mechanical strength of hydrates is approximately 20–100times greater than that of ice(Stern et al.,2004), it is desired to have hydrates surrounding void and fracture decomposition surfaces.Because thermal conductivity of ice exceeds that of hydrates(Waite et al.,2002),in the absence of ice the high conductivity of metals near hydrate formation sites promotes hydrates as the shielding phase.
3.3.3.Ef?cient mass transfer
Ef?cient mass transfer occurs in the surfactant process during the two stages of hydrate formation.Hydrate crystal initiations, as observed and?lmed in the laboratory,begin subsurface in a gas-lean environment where surfactant hydrophobic moieties scavenge enough hydrocarbon gas to serve as nucleation sites and support crystal initiation.In the second stage of hydrate formation,a porous packing of the hydrates on metal surfaces at the gas–water interface provides permeability for interstitial water to react in a gas-rich environment.
3.3.
4.Minimum exterior surface area of the hydrate mass Hydrate decomposition rates increase with gas/solid interfa-cial surface areas,that is,the decomposition surfaces.For this reason,a larger hydrate mass in the478ml test cell contributed to stability.For example,when initial surfactant solution was 100ml,an annular space was left between hydrates building on stainless steel test cell walls and those building on the central Al cylinder,and more hydrate/gas interfacial surfaces for de-composition resulted.In an example where methane hydrates were not ultra-stable,6%of the20,690±1ml of
methane Fig.4.Photographs of test cell interior utilizing boroscope and?ber optics.
(A)Empty cell interior before test;Al tube upright in center for hydrate collection and heat conduction.(B)After methane hydrates form in test cell from100ml of300ppm water–SDS solution;water level below top of Al tube.Because of excess interfacial decomposition surface area,hydrates not ultra-stable.
gas stored in the hydrates evolved in12min and32%of the methane hydrates decomposed in24h.The hydrates cited in this example may be viewed in the photograph of Fig.4,which was taken with a?ber-optic probe transmitting light to and im-age from the test cell.Note that the methane hydrate presented in Fig.4b did not develop ultra-stability,presumably because of large exterior decomposition surface areas.
3.3.5.Symmetry of the hydrate mass
It is thought that the symmetry achieved in hydrate packing around cylinders in the surfactant process leads to fewer high stress points within the hydrate mass and consequently develops fewer fractures and attendant decomposition surfaces.
2074G.Zhang,R.E.Rogers/Chemical Engineering Science63(2008)2066–2074
3.4.Postulated mechanism for ultra-stability
The mechanism that provides ultra-stability from anionic sur-factant solutions is postulated to be the following.Concentra-tions of300–1000ppm of SDS increase localized solubility of methane or natural gas around individual surfactant hydropho-bic moieties,and these gas accumulation sites at the surface and in the subsurface of bulk water become hydrate nuclei.The em-bryo hydrate crystals rapidly buoy to the bulk water surface and adsorb on the cold metal at the water–gas interface.Although sizes of the adsorbing hydrate particles are undetermined,ex-tremely small diameters are indicated as detailed earlier in the paper.
Upon adsorbing on the metal surfaces,small particles solid-ify rapidly as formation heat is conducted away by the highly conductive surfaces.Hydrates build symmetrically from the cylindrical metal surfaces.Small hydrate particles pack closely and minimize sizes of void spaces.Hydrates accumulate as a porous and permeable mass.Hydrocarbon gas perme-ates the porous media and reacts with residual interstitial water–surfactant solution to meld particles into a consolidated mass.Negligible unreacted water is left within the solidi?ed hydrate particles.
Fractures and void spaces within the hydrate mass are mini-mal.Hydrates surround any voids and having a strength greater than ice are able to contain hydrate equilibrium pressures within defect spaces;hydrate mass better sustains high pressures in the smaller voids.
4.Conclusions
Comparable ultra-stabilities of natural gas hydrates as well as methane hydrates were achieved in the laboratory at1atm and268.2K;the ultra-stability extended to as high as270.2K for natural gas hydrates.Ultra-stability of natural gas sII hy-drates were maintained for as long as256h with decomposition measured to be only0.040%of the original gas occluded.The percentage decompositions are based on total hydrates—not on a hydrate remnant after depressurizing.
Ultra-stability of sII natural gas hydrates is reported for the?rst time and is shown to achieve stabilities similar to sI methane hydrates in the surfactant process.
The results indicate a stability mechanism from small hydrate particles being generated by water–surfactant solutions in which defects representing decomposition surfaces in the hydrate mass are minimized.
Acknowledgments
The authors are grateful to US Department of Energy,NETL, for the support provided for portions of the work through grants including DE-FC26-01NT41297to study gas hydrate storage of methane and natural gas utilizing surfactant–water solutions. References
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50万吨年煤气化生产工艺
咸阳职业技术学院生化工程系毕业论文（设计） 50wt/年煤气化工艺设计 1.引言 煤是由古代植物转变而来的大分子有机化合物。我国煤炭储量丰富，分布面广，品种齐全。据中国第二次煤田预测资料，埋深在1000m以浅的煤炭总资源量为2.6万亿t。其中大别山—秦岭—昆仑山一线以北地区资源量约2.45万亿t，占全国总资源量的94%；其余的广大地区仅占6%左右。其中新疆、内蒙古、山西和陕西等四省区占全国资源总量的81.3%，东北三省占 1.6%，华东七省占2.8%，江南九省占1.6%。 煤气化是煤炭的一个热化学加工过程，它是以煤或煤焦原料，以氧气（空气或富氧）、水蒸气或氢气等作气化剂，在高温条件下通过化学反应将煤或煤焦中的可燃部分转化为可燃性的气体的过程。气化时所得的可燃性气体称为煤气，所用的设备称为煤气发生炉。 煤气化技术开发较早，在20世纪20年代，世界上就有了常压固定层煤气发生炉。20世纪30年代至50年代，用于煤气化的加压固定床鲁奇炉、常压温克勒沸腾炉和常压气流床K-T炉先后实现了工业化，这批煤气化炉型一般称为第一代煤气化技术。第二代煤气化技术开发始于20世纪60年代，由于当时国际上石油和天然气资源开采及利用于制取合成气技术进步很快，大大降低了制造合成
气的投资和生产成本，导致世界上制取合成气的原料转向了天然气和石油为主，使煤气化新技术开发的进程受阻，20世纪70年代全球出现石油危机后，又促进了煤气化新技术开发工作的进程，到20世纪80年代，开发的煤气化新技术，有的实现了工业化，有的完成了示范厂的试验，具有代表性的炉型有德士古加压水煤浆气化炉、熔渣鲁奇炉、高温温克勒炉（ETIW）及干粉煤加压气化炉等。 近年来国外煤气化技术的开发和发展，有倾向于以煤粉和水煤浆为原料、以高温高压操作的气流床和流化床炉型为主的趋势。 2.煤气化过程 2.1煤气化的定义 煤与氧气或（富氧空气）发生不完全燃烧反应，生成一氧化碳和氢气的过程称为煤气化。煤气化按气化剂可分为水蒸气气化、空气（富氧空气）气化、空气—水蒸气气化和氢气气化；按操作压力分为：常压气化和加压气化。由于加压气化具有生产强度高，对燃气输配和后续化学加工具有明显的经济性等优点。所以近代气化技术十分注重加压气化技术的开发。目前，将气化压力在P＞2MPa 情况下的气化，统称为加压气化技术；按残渣排出形式可分为固态排渣和液态排渣。气化残渣以固体形态排出气化炉外的称固态排渣。气化残渣以液态方式排出经急冷后变成熔渣排出气化炉外的称液态排渣；按加热方式、原料粒度、汽化程度等还有多种分类方法。常用的是按气化炉内煤料与气化剂的接触方式区分，主要有固定床气化、流化床气化、气流床气化和熔浴床床气化。 2.2 主要反应 煤的气化包括煤的热解和煤的气化反应两部分。煤在加热时会发生一系列的物理变化和化学变化。气化炉中的气化反应，是一个十分复杂的体系，这里所讨论的气化反应主要是指煤中的碳与气化剂中的氧气、水蒸汽和氢气的反应，也包括碳与反应产物之间进行的反应。 习惯上将气化反应分为三种类型：碳—氧之间的反应、水蒸汽分解反应和甲烷生产反应。 2.2.1碳—氧间的反应 碳与氧之间的反应有： C+O2=CO2（1）
煤气化工艺流程
煤气化工艺流程 1、主要产品生产工艺煤气化是以煤炭为主要原料的综合性大型化工企业，主要工艺围绕着煤的洁净气化、综合利用，形成了以城市煤气为主线联产甲醇的工艺主线。 主要产品城市煤气和甲醇。城市燃气是城市公用事业的一项重要基础设施，是城市现代化的重要标志之一，用煤气代替煤炭是提高燃料热能利用率，减少煤烟型大气污染，改善大气质量行之有效的方法之一，同时也方便群众生活，节约时间，提高整个城市的社会效率和经济效益。作为一项环保工程，（其一期工程）每年还可减少向大气排放烟尘万吨、二氧化硫万吨、一氧化碳万吨，对改善河南西部地区城市大气质量将起到重要作用。 甲醇是一种重要的基本有机化工原料，除用作溶剂外，还可用于制造甲醛、醋酸、氯甲烷、甲胺、硫酸二甲酯、对苯二甲酸二甲酯、丙烯酸甲酯等一系列有机化工产品，此外，还可掺入汽油或代替汽油作为动力燃料，或进一步合成汽油，在燃料方面的应用，甲醇是一种易燃液体，燃烧性能良好，抗爆性能好，被称为新一代燃料。甲醇掺烧汽油，在国外一般向汽油中掺混甲醇5?15勉高汽油的辛烷值，避免了添加四乙基酮对大气的污染。 河南省煤气（集团）有限责任公司义马气化厂围绕义马至洛阳、洛阳至郑州煤气管线及豫西地区工业及居民用气需求输出清洁能源，对循环经济建设，把煤化工打造成河南省支柱产业起到重要作用。 2、工艺总流程简介： 原煤经破碎、筛分后，将其中5?50mm级块煤送入鲁奇加压气化炉，在炉内与氧气和水蒸气反应生成粗煤气，粗煤气经冷却后，进入低温甲醇洗净化装置，除去煤气中的CO2和H2S净化后的煤气分为两大部分，一部分去甲醇合成系统，合成气再经压缩机加压至，进入甲醇反应器生成粗甲醇，粗甲醇再送入甲醇精馏系统，制得精甲醇产品存入贮罐；另一部分去净煤气变换装置。合成甲醇尾气及变换气混合后，与剩余部分出低温甲醇洗净煤气混合后，进入煤气冷却干燥装置，将露点降至-25 C后，作为合格城市煤气经长输管线送往各用气城市。生产过程中产生的煤气水进入煤气水分离装置，分离出其中的焦油、中油。分离后煤气水去酚回收和氨回收，回收酚氨后的煤气水经污水生化处理装置处理，达标后排放。低温甲醇洗净化装置排出的H2S到硫回收装置回收硫。空分
煤化工产业概况及其发展趋势
煤化工产业概况及其发 展趋势 集团标准化办公室：[VV986T-J682P28-JP266L8-68PNN]
我国煤化工产业概况及其发展趋势 煤化学加工包括煤的焦化、气化和液化。主要用于冶金行业的煤炭焦化和用于制取合成氨的煤炭气化是传统的煤化工产业，随着社会经济的不断发展，它们将进一步得到发展，同时以获得洁净能源为主要目的的煤炭液化、煤基代用液体燃料、煤气化—发电等煤化工或煤化工能源技术也越来越引起关注，并将成为新型煤化工产业化发展的主要方向。发展新型煤化工产业对煤炭行业产业结构的调整及其综合发展具有重要意义。 1 煤化工产业发展概况 1． 1 煤炭焦化 焦化工业是发展最成熟，最具代表性的煤化工产业，也是冶金工业高炉炼铁、机械工业铸造最主要的辅助产业。目前，全世界的焦炭产量大约为～亿t/a，直接消耗原料精煤约亿t/a 。受世界钢铁产量调整、高炉喷吹技术发展、环境保护以及生产成本增高等原因影响，工业发达国家的机械化炼焦能力处于收缩状态，焦炭国际贸易目前为2500万t/ a。 目前，我国焦炭产量约亿t/a，居世界第一，直接消耗原料煤占全国煤炭消费总量的14%。 全国有各类机械化焦炉约750座以上，年设计炼焦能力约9000万 t/a，其中炭化室高度为4m～5.5m以上的大、中型焦炉产量约占80%。中国大容积焦炉（炭化室高≧6m）已实现国产化，煤气净化技术已达世界先进水平，干熄焦、地面烟尘处理站、污水处理等已进入实用化阶段，焦炭质量显着提高，其主要化工产品的精制技术已达到或接近世界先进水平。 焦炭成为我国的主要出口产品之一，出口量逐年上升，2000年达到1500t/a，已成为全球最大的焦炭出口国。 从20世纪80年代起，煤炭行业的炼焦生产得到逐步发展，其中有的建成向城市或矿区输送人工煤气为主要目的的工厂，有的以焦炭为主要产品。煤炭行业焦化生产普遍存在的问题是：焦炉炉型小、以中小型焦炉为主，受矿区产煤品种限制、焦炭质量调整提高难度较大，采用干法熄焦、烟尘集中处理等新技术少，大多数企业技术进步及现代化管理与其他行业同类工厂相比有较大差距。 1．2 煤气化及其合成技术 1.2.1 煤气化 煤气化技术是煤化工产业化发展最重要的单元技术。全世界现有商业化运行的大规模气化炉414台，额定产气量446×106Nm3/d，前10名的气化厂使用鲁奇、德士古、壳牌3种炉型，原料是煤、渣油、天然气，产品是F-T合成油、电或甲醇等。 煤气化技术在我国被广泛应用于化工、冶金、机械、建材等工业行业和生产城市煤气的企业，各种气化炉大约有9000多台，其中以固定床气化炉为主。近20年来，我国引进的加压鲁奇炉、德士古水煤浆气化炉，主要用于生产合成氨、甲醇或城市煤气。
煤气化技术的现状及发展趋势分析
煤气化技术是现代煤化工的基础，是通过煤直接液化制取油品或在高温下气化制得合成气，再以合成气为原料制取甲醇、合成油、天然气等一级产品及以甲醇为原料制得乙烯、丙烯等二级化工产品的核心技术。作为煤化工产业链中的“龙头”装置，煤气化装置具有投入大、可靠性要求高、对整个产业链经济效益影响大等特点。目前国内外气化技术众多，各种技术都有其特点和特定的适用场合，它们的工业化应用程度及可靠性不同，选择与煤种及下游产品相适宜的煤气化工艺技术是煤化工产业发展中的重要决策。 工业上以煤为原料生产合成气的历史已有百余年。根据发展进程分析，煤气化技术可分为三代。第一代气化技术为固定床、移动床气化技术，多以块煤和小颗粒煤为原料制取合成气，装置规模、原料、能耗及环保的局限性较大；第二代气化技术是现阶段最具有代表性的改进型流化床和气流床技术，其特征是连续进料及高温液态排渣；第三代气化技术尚处于小试或中试阶段，如煤的催化气化、煤的加氢气化、煤的地下气化、煤的等离子体气化、煤的太阳能气化和煤的核能余热气化等。 本文综述了近年来国内外煤气化技术开发及应用的进展情况，论述了固定床、流化床、气流床及煤催化气化等煤气化技术的现状及发展趋势。 1．国内外煤气化技术的发展现状 在世界能源储量中，煤炭约占79%，石油与天然气约占12%。煤炭利用技术的研究和开发是能源战略的重要内容之一。世界煤化工的发展经历了起步阶段、发展阶段、停滞阶段和复兴阶段。20世纪初，煤炭炼焦工业的兴起标志着世界煤化工发展的起步。此后世界煤化工迅速发展，直到20世纪中叶，煤一直是世界有机化学工业的主要原料。随着石油化学工业的兴起与发展，煤在化工原料中所占的比例不断下降并逐渐被石油和天然气替代，世界煤化工技术及产业的发展一度停滞。直到20世纪70年代末，由于石油价格大幅攀升，影响了世界石油化学工业的发展，同时煤化工在煤气化、煤液化等方面取得了显著的进展。特别是20世纪90年代后，世界石油价格长期在高位运行，且呈现不断上升趋势，这就更加促进了煤化工技术的发展，煤化工重新受到了人们的重视。 中国的煤气化工艺由老式的UGI炉块煤间歇气化迅速向世界最先进的粉煤加压气化工艺过渡，同时国内自主创新的新型煤气化技术也得到快速发展。据初步统计，采用国内外先进大型洁净煤气化技术已投产和正在建设的装置有80多套，50%以上的煤气化装置已投产运行，其中采用水煤浆气化技术的装置包括GE煤气化27套（已投产16套），四喷嘴33套（已投产13套），分级气化、多元料浆气化等多套；采用干煤粉气化技术的装置包括Shell煤气化18套（已投产11套）、GSP2套，还有正在工业化示范的LurgiBGL技术、航天粉煤加压气化（HT-L）技术、单喷嘴干粉气化技术和两段式干煤粉加压气化（TPRI）技术等。
煤气化工艺流程
精心整理 煤气化工艺流程 1、主要产品生产工艺 煤气化是以煤炭为主要原料的综合性大型化工企业，主要工艺围绕着煤的洁净气化、综合利用，形成了以城市煤气为主线联产甲醇的工艺主线。 主要产品城市煤气和甲醇。城市燃气是城市公用事业的一项重要基础设施，是城市现代化的重要标志之一，用煤气代替煤炭是提高燃料热能利用率，减少煤烟型大气污染，改善大气质量行之 化碳 15%提 作用。 2 。净化 装置。合成甲醇尾气及变换气混合后，与剩余部分出低温甲醇洗净煤气混合后，进入煤气冷却干燥装置，将露点降至-25℃后，作为合格城市煤气经长输管线送往各用气城市。生产过程中产生的煤气水进入煤气水分离装置，分离出其中的焦油、中油。分离后煤气水去酚回收和氨回收，回收酚氨后的煤气水经污水生化处理装置处理，达标后排放。低温甲醇洗净化装置排出的H2S到硫回收装置回收硫。空分装置提供气化用氧气和全厂公用氮气。仪表空压站为全厂仪表提供合格的仪表空气。 小于5mm粉煤，作为锅炉燃料，送至锅炉装置生产蒸汽，产出的蒸汽一部分供工艺装置用汽
，一部分供发电站发电。 3、主要装置工艺流程 3.1备煤装置工艺流程简述 备煤工艺流程分为三个系统： （1）原煤破碎筛分贮存系统，汽运原煤至受煤坑经1#、2#、3#皮带转载至筛分楼、经节肢筛、破碎机、驰张筛加工后，6~50mm块煤由7#皮带运至块煤仓，小于6mm末煤经6#、11#皮带近至末煤仓。 缓 可 能周期性地加至气化炉中。 当煤锁法兰温度超过350℃时，气化炉将联锁停车，这种情况仅发生在供煤短缺时。在供煤短缺时，气化炉应在煤锁法兰温度到停车温度之前手动停车。 气化炉：鲁奇加压气化炉可归入移动床气化炉，并配有旋转炉篦排灰装置。气化炉为双层压力容器，内表层为水夹套，外表面为承压壁，在正常情况下，外表面设计压力为3600KPa（g），内夹套与气化炉之间压差只有50KPa（g）。 在正常操作下，中压锅炉给水冷却气化炉壁，并产生中压饱和蒸汽经夹套蒸汽气液分离器1
煤化工工艺流程
煤化工工艺流程 典型的焦化厂一般有备煤车间、炼焦车间、回收车间、焦油加工车间、苯加工车间、脱硫车间和废水处理车间等。 焦化厂生产工艺流程 1.备煤与洗煤 原煤一般含有较高的灰分和硫分，洗选加工的目的是降低煤的灰分，使混杂在煤中的矸石、煤矸共生的夹矸煤与煤炭按照其相对密度、外形及物理性状方面的差异加以分离，同时，降低原煤中的无机硫含量，以满足不同用户对煤炭质量的指标要求。 由于洗煤厂动力设备繁多，控制过程复杂，用分散型控制系统DCS改造传统洗煤工艺，这对于提高洗煤过程的自动化，减轻工人的劳动强度，提高产品产量和质量以及安全生产都具有重要意义。
洗煤厂工艺流程图 控制方案 洗煤厂电机顺序启动/停止控制流程框图 联锁/解锁方案：在运行解锁状态下，允许对每台设备进行单独启动或停止；当设置为联锁状态时，按下启动按纽，设备顺序启动，后一设备的启动以前一设备的启动为条件（设备间的延时启动时间可设置），如果前一设备未启动成功，后一设备不能启动，按停止键，则设备顺序停止，在运行过程中，如果其中一台设备故障停止，例如设备2停止，则系统会把设备3和设备4停止，但设备1保持运行。
2.焦炉与冷鼓 以100万吨/年-144孔-双炉-4集气管-1个大回流炼焦装置为例，其工艺流程简介如下：
100万吨/年焦炉_冷鼓工艺流程图 控制方案 典型的炼焦过程可分为焦炉和冷鼓两个工段。这两个工段既有分工又相互联系，两者在地理位置上也距离较远，为了避免仪表的长距离走线，设置一个冷鼓远程站及给水远程站，以使仪表线能现场就近进入DCS控制柜，更重要的是，在集气管压力调节中，两个站之间有着重要的联锁及其排队关系，这样的网络结构形式便于可以实现复杂的控制算法。
煤气化工艺流程
煤气化工艺流程 1、主要产品生产工艺 煤气化是以煤炭为主要原料的综合性大型化工企业，主要工艺围绕着煤的洁净气化、综合利用，形成了以城市煤气为主线联产甲醇的工艺主线。 主要产品城市煤气和甲醇。城市燃气是城市公用事业的一项重要基础设施，是城市现代化的重要标志之一，用煤气代替煤炭是提高燃料热能利用率，减少煤烟型大气污染，改善大气质量行之有效的方法之一，同时也方便群众生活，节约时间，提高整个城市的社会效率和经济效益。作为一项环保工程，（其一期工程）每年还可减少向大气排放烟尘1.86万吨、二氧化硫3.05万吨、一氧化碳0.46万吨，对改善河南西部地区城市大气质量将起到重要作用。 甲醇是一种重要的基本有机化工原料，除用作溶剂外，还可用于制造甲醛、醋酸、氯甲烷、甲胺、硫酸二甲酯、对苯二甲酸二甲酯、丙烯酸甲酯等一系列有机化工产品，此外，还可掺入汽油或代替汽油作为动力燃料，或进一步合成汽油，在燃料方面的应用，甲醇是一种易燃液体，燃烧性能良好，抗爆性能好，被称为新一代燃料。甲醇掺烧汽油，在国外一般向汽油中掺混甲醇5～15%提高汽油的辛烷值，避免了添加四乙基酮对大气的污染。 河南省煤气（集团）有限责任公司义马气化厂围绕义马至洛阳、洛阳至郑州煤气管线及豫西地区工业及居民用气需求输出清洁能源，对循环经济建设，把煤化工打造成河南省支柱产业起到重要作用。 2、工艺总流程简介： 原煤经破碎、筛分后，将其中5～50mm级块煤送入鲁奇加压气化炉，在炉内与氧气和水蒸气反应生成粗煤气，粗煤气经冷却后，进入低温甲醇洗净化装置
，除去煤气中的CO2和H2S。净化后的煤气分为两大部分，一部分去甲醇合成系统，合成气再经压缩机加压至5.3MPa，进入甲醇反应器生成粗甲醇，粗甲醇再送入甲醇精馏系统，制得精甲醇产品存入贮罐；另一部分去净煤气变换装置。合成甲醇尾气及变换气混合后，与剩余部分出低温甲醇洗净煤气混合后，进入煤气冷却干燥装置，将露点降至-25℃后，作为合格城市煤气经长输管线送往各用气城市。生产过程中产生的煤气水进入煤气水分离装置，分离出其中的焦油、中油。分离后煤气水去酚回收和氨回收，回收酚氨后的煤气水经污水生化处理装置处理，达标后排放。低温甲醇洗净化装置排出的H2S到硫回收装置回收硫。空分装置提供气化用氧气和全厂公用氮气。仪表空压站为全厂仪表提供合格的仪表空气。 小于5mm粉煤，作为锅炉燃料，送至锅炉装置生产蒸汽，产出的蒸汽一部分供工艺装置用汽，一部分供发电站发电。 3、主要装置工艺流程 3.1备煤装置工艺流程简述 备煤工艺流程分为三个系统： （1）原煤破碎筛分贮存系统，汽运原煤至受煤坑经1#、2#、3#皮带转载至筛分楼、经节肢筛、破碎机、驰张筛加工后，6~50mm块煤由7#皮带运至块煤仓，小于6mm末煤经6#、11#皮带近至末煤仓。 （2）最终筛分系统：块煤仓内块煤经8#、9#皮带运至最终筛分楼驰张筛进行检查性筛分。大于6mm块煤经10#皮带送至200#煤斗，筛下小于6mm末煤经14#皮带送至缓冲仓。 （3）电厂上煤系统：末煤仓内末煤经12#、13#皮带转至5#点后经16#皮
(能源化工行业)我国煤化工产业概况及其发展方向
（能源化工行业）我国煤化工产业概况及其发展方向
我国煤化工产业概况及其发展趋势 煤化学加工包括煤的焦化、气化和液化。主要用于冶金行业的煤炭焦化和用于制取合成氨的煤炭气化是传统的煤化工产业，随着社会经济的不断发展，它们将进壹步得到发展，同时以获得洁净能源为主要目的的煤炭液化、煤基代用液体燃料、煤气化—发电等煤化工或煤化工能源技术也越来越引起关注，且将成为新型煤化工产业化发展的主要方向。发展新型煤化工产业对煤炭行业产业结构的调整及其综合发展具有重要意义。 1煤化工产业发展概况 1．1煤炭焦化 焦化工业是发展最成熟，最具代表性的煤化工产业，也是冶金工业高炉炼铁、机械工业铸造最主要的辅助产业。目前，全世界的焦炭产量大约为3.2～3.4亿t/a，直接消耗原料精煤约4.5亿t/a。受世界钢铁产量调整、高炉喷吹技术发展、环境保护以及生产成本增高等原因影响，工业发达国家的机械化炼焦能力处于收缩状态，焦炭国际贸易目前为2500万t/a。 目前，我国焦炭产量约1.2亿t/a，居世界第壹，直接消耗原料煤占全国煤炭消费总量的14%。全国有各类机械化焦炉约750座之上，年设计炼焦能力约9000万t/a，其中炭化室高度为4m～5.5m之上的大、中型焦炉产量约占80%。中国大容积焦炉（炭化室高≧6m）已实现国产化，煤气净化技术已达世界先进水平，干熄焦、地面烟尘处理站、污水处理等已进入实用化阶段，焦炭质量显著提高，其主要化工产品的精制技术已达到或接近世界先进水平。 焦炭成为我国的主要出口产品之壹，出口量逐年上升，2000年达到1500t/a，已成为全球最大的焦炭出口国。 从20世纪80年代起，煤炭行业的炼焦生产得到逐步发展，其中有的建成向城市或矿区输送人工煤气为主要目的的工厂，有的以焦炭为主要产品。煤炭行业焦化生产普遍存在的问题是：焦炉炉型小、以中小型焦炉为主，受矿区产煤品种限制、焦炭质量调整提高难度较大，采用干法熄焦、烟尘集中处理等新技术少，大多数企业技术进步及现代化管理和其他行业同类工厂相比有较大差距。 1．2煤气化及其合成技术 1.2.1煤气化 煤气化技术是煤化工产业化发展最重要的单元技术。全世界现有商业化运行的大规模气化炉414台，额定产气量446×106Nm3/d，前10名的气化厂使用鲁奇、德士古、壳牌3种炉型，原料是煤、渣油、天然气，产品是F-T合成油、电或甲醇等。 煤气化技术在我国被广泛应用于化工、冶金、机械、建材等工业行业和生产城市煤气的企业，各种气化炉大约有9000多台，其中以固定床气化炉为主。近20年来，我国引进的加压鲁奇炉、德士古水煤浆气化炉，主要用于生产合成氨、甲醇或城市煤气。 煤气化技术的发展和作用引起国内煤炭行业的关注。“九五”期间，兖矿集团和国内高校、科研机构合作，开发完成了22t/d多喷嘴水煤浆气化炉中试装置，且进行了考核试验。 结果表明：有效气体成分达83%，碳转化率>98%，分别比相同条件下的德士古生产装置高1.5%～2%、2%～3%；比煤耗、比氧耗均低于德士古7%。该成果标志我国自主开发的先进气化技术取得突破性进展。 1.2.2煤气化合成氨 以煤为原料、采用煤气化—合成氨技术是我国化肥生产的主要方式，目前我国有800多家中小型化肥厂采用水煤气工艺，共计约4000台气化炉，每年消费原料煤（或焦炭）4000多万t，合成氨产量约占全国产量的60%。化肥用气化炉的炉型以UGI型和前苏联的Д型为主，直径由2.2m至3.6m不等，该类炉型老化、技术落后。加压鲁奇炉、德士古炉是近年来引进用于合成氨生产的主要炉型。
煤气化制甲醇工艺流程
煤气化制甲醇工艺流程 1 煤制甲醇工艺 气化 a）煤浆制备 由煤运系统送来的原料煤干基（<25mm）或焦送至煤贮斗，经称重给料机控制输送量送入棒磨机，加入一定量的水，物料在棒磨机中进行湿法磨煤。为了控制煤浆粘度及保持煤浆的稳定性加入添加剂，为了调整煤浆的PH值，加入碱液。出棒磨机的煤浆浓度约65%，排入磨煤机出口槽，经出口槽泵加压后送至气化工段煤浆槽。煤浆制备首先要将煤焦磨细，再制备成约65%的煤浆。磨煤采用湿法，可防止粉尘飞扬，环境好。用于煤浆气化的磨机现在有两种，棒磨机与球磨机；棒磨机与球磨机相比，棒磨机磨出的煤浆粒度均匀，筛下物少。煤浆制备能力需和气化炉相匹配，本项目拟选用三台棒磨机，单台磨机处理干煤量43～ 53t/h，可满足60万t/a甲醇的需要。 为了降低煤浆粘度，使煤浆具有良好的流动性，需加入添加剂，初步选择木质磺酸类添加剂。 煤浆气化需调整浆的PH值在6～8，可用稀氨水或碱液，稀氨水易挥发出氨，氨气对人体有害，污染空气，故本项目拟采用碱液调整煤浆的PH值，碱液初步采用42％的浓度。 为了节约水源，净化排出的含少量甲醇的废水及甲醇精馏废水均可作为磨浆水。 b）气化 在本工段，煤浆与氧进行部分氧化反应制得粗合成气。 煤浆由煤浆槽经煤浆加压泵加压后连同空分送来的高压氧通过烧咀进入气化炉，在气化炉中煤浆与氧发生如下主要反应： CmHnSr+m/2O2—→mCO+（n/2-r）H2+rH2S CO+H2O—→H2+CO2 反应在6.5MPa（G）、1350～1400℃下进行。 气化反应在气化炉反应段瞬间完成，生成CO、H2、CO2、H2O和少量CH4、H2S等气体。 离开气化炉反应段的热气体和熔渣进入激冷室水浴，被水淬冷后温度降低并被水蒸汽饱和后出气化炉；气体经文丘里洗涤器、碳洗塔洗涤除尘冷却后送至变换工段。 气化炉反应中生成的熔渣进入激冷室水浴后被分离出来，排入锁斗，定时排入渣池，由扒渣机捞出后装车外运。 气化炉及碳洗塔等排出的洗涤水（称为黑水）送往灰水处理。 c）灰水处理 本工段将气化来的黑水进行渣水分离，处理后的水循环使用。 从气化炉和碳洗塔排出的高温黑水分别进入各自的高压闪蒸器，经高压闪蒸浓缩后的黑水混合，经低压、两级真空闪蒸被浓缩后进入澄清槽，水中加入絮凝剂使其加速沉淀。澄清槽底部的细渣浆经泵抽出送往过滤机给料槽，经由过滤机给料泵加压后送至真空过滤机脱水，渣饼由汽车拉出厂外。 闪蒸出的高压气体经过灰水加热器回收热量之后，通过气液分离器分离掉冷凝液，然后进入变换工段汽提塔。 闪蒸出的低压气体直接送至洗涤塔给料槽，澄清槽上部清水溢流至灰水槽，由灰水泵分别送至洗涤塔给料槽、气化锁斗、磨煤水槽，少量灰水作为废水排往废水处理。 洗涤塔给料槽的水经给料泵加压后与高压闪蒸器排出的高温气体换热后送碳洗塔循环
国内煤气化技术评述与展望
2012年 第15期 广 东 化 工 第39卷 总第239期 https://www.docsj.com/doc/1710015954.html, · 59 · 国内煤气化技术评述与展望 付长亮 (河南化工职业学院，河南 郑州 450042) [摘 要]依据煤气化技术的常用分类标准和评价指标，分析研究了国内所用的煤气化技术的优势与不足。综合考虑原料广泛性、技术先进性、投资成本等因素，认为航天炉干粉煤气化技术具有适应的煤种多、气化效率高、生产能力大、碳转化率高、投资省、操作费用低等优势，在未来的煤化工产品生产中将会得到普遍的应用。 [关键词]煤气化技术；评述；展望 [中图分类号]TQ [文献标识码]A [文章编号]1007-1865(2012)15-0059-02 Review and Prospects of Domestic Coal Gasification Technology Fu Changliang (Henan V ocational College of Chemical Technology, Zhenzhou 450042, China) Abstract: According to common classification standard and evaluation index, advantages and disadvantages of domestic coal gasification technology were analyzed and studied. Considering comprehensively the raw material extensive, technology advanced and investment cost, it was thought that HT-L dry powder coal gasification had the vast potential for future development, because of the more quantity of coal type used, higher gasification efficiency, larger production capacity, higher carbon conversion, lower investment cost. Keywords: coal gasification technology ；review ；prospects 1 煤气化及其评价指标 煤气化指在高温下煤和气化剂作用生成煤气的过程。可简单表示如下： +???→高温 煤气化剂煤气 其中的气化剂主要指空气、纯氧和水蒸汽。煤气化所制得的煤气是一种可燃性气体，主要成分为CO 、H 2、CO 2和CH 4，可作为清洁能源和多种化工产品的原料。因此，煤气化技术在煤化工中处于非常重要的地位。 煤气化反应主要在气化炉(或称煤气发生炉、煤气炉)内进行。不同的煤气化技术主要区别在于所用的气化炉的形式不同。 通常，对煤气化技术的评价主要从气化效率、冷煤气效率、碳转化率和有效气体产率四个方面进行。气化效率衡量原料(煤和气化剂)的热值转化为可利用热量(煤气的热值和产生蒸汽的热值)的情况，是最常用的评价指标，标志着煤气化技术的能耗高低。冷煤气效率衡量原料的热值转化为煤气热值的情况，是制得煤气量多少及质量高低的标志。碳转化率衡量煤中有多少碳转化进入到煤气中，是煤利用率高低的标志。有效气体产率衡指单位煤耗能产出多少有效气体(CO+H 2)，是对煤气化技术生产有价值成分效果好坏的评价。这四个指标不完全独立，从不同的方面反映了煤气化技术中人们最关注的问题。 2 煤气化技术的分类 煤气化的分类方法较多，但最常用的分类方法是按煤与气化剂在气化炉内运动状态来分。此法，将煤气化技术分为如下几种。 2.1 固定床气化 固定床气化也称移动床气化，一般以块煤或煤焦为原料。煤由气化炉顶加入，气化剂由炉底送入。流动气体的上升力不致使固体颗粒的相对位置发生变化，即固体颗粒处于相对固定状态。气化炉内各反应层高度亦基本上维持不变。因而称为固定床气化。另外，从宏观角度看，由于煤从炉顶加入，含有残炭的灰渣自炉底排出，气化过程中，煤粒在气化炉内逐渐并缓慢往下移动，因而又称为移动床气化。目前，国内采用此方法的煤气化技术主要有固定床间歇气化法和加压鲁奇气化法。 2.2 流化床气化 流化床煤气化法以小颗粒煤为气化原料，这些细粒煤在自下而上的气化剂的作用下，保持着连续不断和无秩序的沸腾和悬浮状态运动，迅速地进行着混和和热交换，其结果导致整个床层温度和组成的均一。目前，国内属于此方法的煤气化技术主要有恩德粉煤气化技术和ICC 灰融聚气化法。 2.3 气流床气化 气流床气化是一种并流式气化。气化剂(氧与蒸汽)与煤粉一同进入气化炉，在1500~1900 ℃高温下，将煤部分氧化成CO 、H 2、CO 2等气体，残渣以熔渣形式排出气化炉。也可将煤粉制成 煤浆，用泵送入气化炉。在气化炉内，煤炭细粉粒与气化剂经特殊喷嘴进入反应室，会在瞬间着火，发生火焰反应，同时处于不充分的氧化条件下。因此，其热解、燃烧以及吸热的气化反应，几乎是同时发生的。随气流的运动，未反应的气化剂、热解挥发物及燃烧产物裹挟着煤焦粒子高速运动，运动过程中进行着煤焦颗粒的气化反应。这种运动形态，相当于流态化技术领域里对固体颗粒的“气流输送”，习惯上称为气流床气化。属于此类方法的煤气化技术较多，国内主要有壳牌干粉煤气化法、德士古水煤浆气化法、GSP 干粉煤气化法、航天炉干粉煤气化等[1-3]。 3 国内主要煤气化技术评述 3.1 固定床间歇式气化 块状无烟煤或焦炭在气化炉内形成固定床。在常压下，空气和水蒸汽交替通过气化炉。通空气时，产生吹风气，主要为了积累能量，提高炉温。通水蒸汽时，利用吹风阶段积累的能量，生产水煤气。空气煤气和水煤气以适当比例混合，制得合格原料气。 该技术是20世纪30年代开发成功的。优点为投资少、操作简单。缺点为气化效率低、对原料要求高、能耗高、单炉生产能力小。间歇制气过程中，大量吹风气排空。每吨合成氨吹风气放空多达5000 m 3。放空气体中含CO 、CO 2、H 2、H 2S 、SO 2、NO x 及粉灰。煤气冷却洗涤塔排出的污水含有焦油、酚类及氰化物，对环境污染严重。我国中小化肥厂有900余家，多数采用该技术生产合成原料气。随着能源和环境的政策要求越来越高，不久的将来，会逐步被新的煤气化技术所取代。 3.2 鲁奇加压连续气化 20世纪30年代，由德国鲁奇公司开发。在高温、高压下，用纯氧和水蒸汽，连续通过由煤形成的固定床。氧和煤反应放出的热量，正好能供应水蒸汽和煤反应所需要的热量，从而维持了热量平衡，炉温恒定，制气过程连续。 鲁奇加压气化法生产的煤气中除含CO 和H 2外， 含CH 4高达10 %~12 %，可作为城市煤气、人工天然气、合成气使用。相比较于固定床间歇气化，其优点是炉子生产能大幅提高，煤种要求适当放宽。其缺点是气化炉结构复杂，炉内设有破粘机、煤分布器和炉篦等转动设备，制造和维修费用大，入炉仍需要是块煤，出炉煤气中含焦油、酚等，污水处理和煤气净化工艺复杂。 3.3 恩德粉煤气化技术 恩德粉煤气化技术利用粉煤(<10 mm)和气化剂在气化炉内形成沸腾流化床，在高温下完成煤气化反应，生产需要的煤气。 由于所用的原料为粉煤，煤种的适应性比块煤有所放宽，原料成本也得到大幅度降低。得益于流化床的传质、传热效果大大优于固定床，恩德粉煤气化炉的生产能力比固定床间歇制气有较大幅度的提高。由于操作温度不高，导致气化效率和碳转化率都不高，且存在废水、废渣处理困难等问题。此技术多用于替代固定床间歇制气工艺[4-6]。 [收稿日期] 2012-07-21 [作者简介] 付长亮(1968-)，男，河南荥阳人，硕士，高级讲师，主要从事化工工艺的教学与研究。
煤气化技术的现状和发展趋势
煤气化技术的现状和发展趋势 1、水煤浆加压气化 1.1 德士古水煤浆加压气化工艺（TGP） 美国Texaco 公司在渣油部分氧化技术基础上开发了水煤浆气化技术，TGP 工艺采用水煤浆进料，制成质量分数为60%~65％的水煤浆，在气流床中加压气化，水煤浆和氧气在高温高压下反应生成合成气，液态排渣。气化压力在2.7~6.5MPa，提高气化压力，可降低装置投入，有利于降低能耗；气化温度在1 300~1 400℃，煤气中有效气体（CO+H2）的体积分数达到80％，冷煤气效率为70％~76％，设备成熟，大部分已能国产化。世界上德士古气化炉单炉最大投煤量为2 000t/d。德士古煤气化过程对环境污染影响较小。 根据气化后工序加工不同产品的要求，加压水煤浆气化有三种工艺流程：激冷流程、废锅流程和废锅激冷联合流程。对于合成氨生产多采用激冷流程，这样气化炉出来的粗煤气，直接用水激冷，被激冷后的粗煤气含有较多水蒸汽，可直接送入变换系统而不需再补加蒸汽，因无废锅投资较少。如产品气用作燃气透平循环联合发电工程时，则多采用废锅流程，副产高压蒸汽用于蒸汽透平发电机组。如产品气用作羟基合成气并生产甲醇时，仅需要对粗煤气进行部分变换，通常采用废锅和激冷联合流程，亦称半废锅流程，即从气化炉出来粗煤气经辐射废锅冷却到700℃左右，然后用水激冷到所需要的温度，使粗煤气显热产生的蒸汽能满足后工序部分变换的要求。 1.2 新型（多喷嘴对置式）水煤浆加压气化 新型（多喷嘴对置式）水煤浆加压气化技术是最先进煤气化技术之一，是在德士古水煤浆加压气化法的基础上发展起来的。2000 年，华东理工大学、鲁南化肥厂（水煤浆工程国家中心的依托单位）、中国天辰化学工程公司共同承担的新型（多喷嘴对置）水煤浆气化炉中试工程，经过三方共同努力，于7 月在鲁化建成投料开车成功，通过国家主管部门的鉴定及验收。2001 年2 月10 日获得专利授权。新型气化炉以操作灵活稳定，各项工艺指标优于德士古气化工艺指标引起国家科技部的高度重视和积极支持，主要指标体现为：有效气成分（CO+H2）的体积分数为~83％，比相同条件下的ChevronTexaco 生产装置高1.5~2.0 个百分点；碳转化率＞98％，比ChevronTexaco 高2~3 个百分点；比煤耗、比氧耗均比ChevronTexaco 降低7％。 新型水煤浆气化炉装置具有开车方便、操作灵活、投煤负荷增减自如的特点，同时综合能耗比德士古水煤浆气化低约7％。其中第一套装置日投料750t 能力新型多喷嘴对置水煤浆加压气化炉于2004 年12 月在山东华鲁恒升化学有限公司建成投料成功，运行良好。另一套装置两台日投煤1 150t 的气化炉也在兖矿国泰化工有限公司于2005 年7 月建成投料成功，并于2005 年10 月正式投产，2006 年已达到并超过设计能力，目前运行状况良好。该技术在国内已获得有效推广，并已出口至美国。 2、干粉煤加压气化工艺 2.1 壳牌干粉煤加压气化工艺（SCGP） Shell 公司于1972 年开始在壳牌公司阿姆斯特丹研究院（KSLA）进行煤气化研究，1978 年第一套中试装置在德国汉堡郊区哈尔堡炼油厂建成并投入运行，1987 年在美国休斯顿迪尔·帕克炼油厂建成日投煤量250~400t 的示范装置，1993年在荷兰的德姆克勒（Demkolec）电厂建成投煤量2 000t/d 的大型煤气化装置，用于联合循环发电（IGCC），称作SCGP 工业生产装置。装置开工率最高达73％。该套装置的成功投运表明SCGP 气化技术是先进可行的。 Shell 气化炉为立式圆筒形气化炉，炉膛周围安装有由沸水冷却管组成的膜式水冷壁，其内壁衬有耐热涂层，气化时熔融灰渣在水冷壁内壁涂层上形成液膜，沿壁顺流而下进行分
现代煤气化技术发展趋势及应用综述_汪寿建
2016年第35卷第3期CHEMICAL INDUSTRY AND ENGINEERING PROGRESS ·653· 化工进展 现代煤气化技术发展趋势及应用综述 汪寿建 （中国化学工程集团公司，北京 100007） 摘要：现代煤气化技术是现代煤化工装置中的重要一环，涉及整个煤化工装置的正常运行。本文分别介绍了中国市场各种现代煤气化工艺应用现状，叙述汇总了其工艺特点、应用参数、市场数据等。包括第一类气流床加压气化工艺，又可分为干法煤粉加压气化工艺和湿法水煤浆加压气化工艺。干法气化代表性工艺包括Shell炉干煤粉气化、GSP炉干煤粉气化、HT-LZ航天炉干煤粉气化、五环炉（宁煤炉）干煤粉气化、二段加压气流床粉煤气化、科林炉（CCG）干煤粉气化、东方炉干煤粉气化。湿法气化代表性工艺包括 GE水煤浆加压气化、四喷嘴水煤浆加压气化、多元料浆加压气化、熔渣-非熔渣分级加压气化（改进型为清华炉）、E-gas(Destec)水煤浆气化。第二类流化床粉煤加压气化工艺，主要有代表性工艺包括U-gas灰熔聚流化床粉煤气化、SES褐煤流化床气化、灰熔聚常压气化（CAGG）。第三类固定床碎煤加压气化，主要有代表性工艺包括鲁奇褐煤加压气化、碎煤移动床加压气化和BGL碎煤加压气化等。文章指出应认识到煤气化技术的重要性，把引进国外先进煤气化技术理念与具有自主知识产权的现代煤化工气化技术有机结合起来。 关键词：煤气化；市场应用；气化特点；参数数据分析 中图分类号：TQ 536.1 文献标志码：A 文章编号：1000–6613（2016）03–0653–12 DOI：10.16085/j.issn.1000-6613.2016.03.001 Development and applicatin of modern coal gasification technology WANG Shoujian （China National Chemical Engineering Group Corporation，Beijing100007，China）Abstract：Modern coal gasification technology is an important part of modern coal chemical industrial plants，involving stable operation of the entire coal plant. This paper introduces application of modern coal gasification technologies in China，summarizes characteristics of gasification processes，application parameters，market data，etc. The first class gasification technology is entrained-bed gasification process，which can be divided into dry pulverized coal pressurized gasification and wet coal-water slurry pressurized gasification. The typical dry pulverized coal pressurized gasification technologies include Shell Gasifier，GSP Gasifier，HT-LZ Gasifier，WHG (Ning Mei) Gasifier，Two-stage Gasifier，CHOREN CCG Gasifier，SE Gasifier. The typical wet coal-water slurry pressurized gasification technologies include GE (Texaco) Gasifier，coal-water slurry gasifier with opposed multi-burners，Multi-component Slurry Gasifier，Non-slag/slag Gasifier (modified as Tsinghua Gasifier)，E-gas (Destec) Gasifier. The second class gasification technology is fluidized-bed coal gasification process. The typical fluidized-bed coal gasification technologies include U-gas Gasifier，SES Lignite Gasifier，CAGG Gasifier. The third class gasification technology is fixed-bed coal gasification process. The typical fixed-bed coal gasification technologies include Lurgi Lignite 收稿日期：2015-09-14；修改稿日期：2015-12-17。 作者：汪寿建（1956—），男，教授级高级工程师，中国化学工程集团公司总工程师，长期从事化工、煤化工工程设计、开发及技术管理工作。E-mail wangsj@https://www.docsj.com/doc/1710015954.html,。
煤气化工艺资料
煤化工是以煤为原料，经过化学加工使煤转化为气体，液体，固体燃料以及化学品的过程，生产出各种化工产品的工业。 煤化工包括煤的一次化学加工、二次化学加工和深度化学加工。煤的气化、液化、焦化，煤的合成气化工、焦油化工和电石乙炔化工等，都属于煤化工的范围。而煤的气化、液化、焦化（干馏）又是煤化工中非常重要的三种加工方式。 煤的气化、液化和焦化概要流程图 一.煤炭气化
煤炭气化是指煤在特定的设备内，在一定温度及压力下使煤中有机质与气化剂（如蒸汽/空气或氧气等）发生一系列化学反应，将固体煤转化为含有CO、H2、CH4等可燃气体和CO2、N2等非可燃气体的过程。 煤的气化的一般流程图 煤炭气化包含一系列物理、化学变化。而化学变化是煤炭气化的主要方式，主要的化学反应有： 1、水蒸气转化反应C+H2O=CO+H2 2、水煤气变换反应CO+ H2O =CO2+H2 3、部分氧化反应C+0.5 O2=CO 4、完全氧化（燃烧）反应C+O2=CO2 5、甲烷化反应CO+2H2=CH4 6、Boudouard反应C+CO2=2CO 其中1、6为放热反应，2、3、4、5为吸热反应。 煤炭气化时，必须具备三个条件，即气化炉、气化剂、供给热量，三者缺一不可。 煤炭气化按气化炉内煤料与气化剂的接触方式区分，主要有： 1) 固定床气化：在气化过程中，煤由气化炉顶部加入，气化剂由气化炉底部加入，煤料与气化剂逆流接触，相对于气体的上升速度而言，煤料下降速度很慢，甚至可视为固定不动，因此称之为固定床气化；而实际上，煤料在气化过程中是以很慢的速度向下移动的，比
较准确的称其为移动床气化。 2) 流化床气化：它是以粒度为0-10mm的小颗粒煤为气化原料，在气化炉内使其悬浮分散在垂直上升的气流中，煤粒在沸腾状态进行气化反应，从而使得煤料层内温度均一，易于控制，提高气化效率。 3) 气流床气化。它是一种并流气化，用气化剂将粒度为100um以下的煤粉带入气化炉内，也可将煤粉先制成水煤浆，然后用泵打入气化炉内。煤料在高于其灰熔点的温度下与气化剂发生燃烧反应和气化反应，灰渣以液态形式排出气化炉。 4) 熔浴床气化。它是将粉煤和气化剂以切线方向高速喷入一温度较高且高度稳定的熔池内，把一部分动能传给熔渣，使池内熔融物做螺旋状的旋转运动并气化。目前此气化工艺已不再发展。 以上均为地面气化，还有地下气化工艺。 根据采用的气化剂和煤气成分的不同，可以把煤气分为四类：1.以空气作为气化剂的空气煤气；2.以空气及蒸汽作为气化剂的混合煤气，也被称为发生炉煤气；3.以水蒸气和氧气作为气化剂的水煤气；4.以蒸汽及空气作为气化剂的半水煤气，也可是空气煤气和水煤气的混合气。 几种重要的煤气化技术及其技术性能比较 1.Lurgi炉固定床加压气化法对煤质要求较高，只能用弱粘结块煤，冷煤气效率最高，气化强度高，粗煤气中甲烷含量较高，但净化系统复杂，焦油、污水等处理困难。 鲁奇煤气化工艺流程图