 Home > Coatings News > Coating Technologies > 【Deep Coating Society Industry Analysis】The large refining and chemical industry has been put into production one after another, how will the by-products carbon four, carbon five, and carbon nine develop? What are the downstream applications?

【Deep Coating Society Industry Analysis】The large refining and chemical industry has been put into production one after another, how will the by-products carbon four, carbon five, and carbon nine develop? What are the downstream applications?

 Last Update: 2022-10-25
 Source: Internet
 Author: User

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Carbon IV is usually a product or mixture
of butane, 1-butene, 2-butene, isobutene, butadiene, etc.
The comprehensive utilization of carbon four is also crucial
for petrochemical enterprises because of its abundant raw material sources, a wide range of downstream applications, and great differences in the physical and chemical properties of different components.
The source of
carbon four01 refineries mainly comes from the refinery's catalytic cracking unit, coking unit, hydrocracking unit, etc.
, of which the catalytic cracking unit accounts for the dominant
carbon four of the refinery.
Typically, carbon four is used as a component in liquefied gas and mixed with propane and the like as fuel
.
However, in recent years, with the integration of refining and chemical industry, ethylene raw materials have become lighter, and the added value of carbon four in refineries has gradually increased
.

02 Pyrolysis ethylene plant Pyrolysis ethylene plant generally has by-product carbon four, of which naphtha as raw material cracking has more carbon four content, other ethane, propane, butane cracking carbon four content is relatively small
.
Naphtha pyrolysis ethylene by-product crude carbon four, in which the component after extraction of butadiene is extracted as residual oil-1, and the component after continuing to pump isobutylene is divided into residual oil-2
.
There are also cracking ethylene plants that convert 2-butene in carbon four with ethylene to produce propylene
.

03 The by-product mixed carbon four of the MTO device accounts for a small proportion of hydrocarbon products, the main components are 1-butene and 2-butene, and the remaining components are butane, isobutylene and butadiene
.
Due to the small output of carbon four in the MTO, it is difficult to carry out deep processing alone, and the carbon four of social resources can be gathered together for comprehensive utilization
.

Oil and gas fields and shale gas moisture NGL In traditional oil and gas exploitation, there will be oilfield associated gas, which will contain carbon four components, but most of them are alkanes
.
Moisture in shale gas extraction can also contain butane
.
But different oil and gas fields have different
compositional content.
In addition to combustion purposes, n-butane in alkane carbon IV is suitable as a raw material for cracking ethylene, and isobutane is suitable for dehydrogenation to produce isobutylene
.

Carbon IV downstream applications Carbon IV has a wide range of downstream applications
, and can be applied downstream to
mixtures or single components thereof.
C4 has the lowest added value as a liquefied gas fuel, and the high olefin content also affects combustion performance
.
Butadiene in carbon IV of pyrolysis ethylene plant plant is one of the most bulk commodities, and the more mature applications are MTBE, methyl ethyl ketone, maleic anhydride and other products
.
The usual downstream applications of carbon four are as follows:
01 aromatized low molecular weight hydrocarbons are converted into mixed aromatic hydrocarbons
containing benzene, toluene and xylene through aromatization reactions.
Then, through a series of separations, the final result is a standard mixture, light aromatic and heavy aromatic hydrocarbon, as well as a by-product of low olefin liquefied gas and a small amount of dry gas
.
At a time when refined oil products were in short supply, local refineries had a lot of aromatization capacity, mainly for oil blending, but now the economy has decreased
significantly.

02 One of the largest products in butadiene carbon four, mainly used in synthetic rubber (styrene-butadiene, cis-butyl, nitrile, etc.
), ABS, styrene-butadiene latex, elastomer (SBS, SEBS, etc.
), adiponitrile, thiophene, tetrahydrophthalic anhydride and other uses
.
Butadiene is more difficult to store, usually under pressure, or at low temperatures to prevent autopolymerization
.
Butadiene boats and tankers can be used with LPG boats and tankers, but the pressure level and oxygen content required are more demanding
.

03 isobutylene because isobutylene and butylene in mixed carbon four usually coexist, it is difficult to separate by physical methods, generally through methanol etherification, in which isobutylene reacts with methanol to generate MTBE
.
MTBE can be used for gasoline blending or recracking to produce high-purity isobutylene
.
High-purity isobutylene is a raw material for the production of butyl rubber, and can also be isobutylene to synthesize MMA, polyisobutylene, antioxidants and other products
.
In recent years, the number of plants for the production of isobutylene by dehydrogenation of isobutane has also increased
.

04 1-butene and 2-butene can be converted
by isomerization.
1-butene can be used as a comonomer of LLDPE, synthesized poly1-butene, etc.
; 2-Butene is used in the production of methyl ethyl ketone, sec butyl acetate, etc.

Butylene is produced by oxidative dehydrogenation (not direct dehydrogenation), but the material consumption of raw materials is high, and the cost of carbon four extraction is high
.

05 butane is divided into n-butane and isobutane, n-butane in addition to combustion purposes, can be used to crack ethylene raw materials, synthesis of maleic anhydride, etc.
; The synthesis of maleic anhydride from n-butane will compete
with pure benzene as a raw material.
Isobutane has a poor yield as cracked ethylene and can be isoformed into n-butane, but isomerization is required for a certain scale to be economical
.
Isobutane can be synthesized with butylene for alkylated gasoline, and isobutylene can also be dehydrogenated to produce isobutylene
.

Pyrolysis C5 is a by-product
of the process of steam cracking ethylene (referred to as naphtha ethylene) from cracking raw materials such as naphtha or other heavy materials.
Pyrolysis C5 contains more than 30 components with similar boiling points, which have high utilization value, of which the components with more content are isoprene, meta-prene and cyclopentadiene, which account for about 40%~55% of the total amount of C5 (mass fraction, the same below).

Pyrolysis C5 also contains 15%~25% of monoolefins
such as 1-pentene, 2-methyl-1-butene, 2-methyl-2-butene.
The main source of
cracking C5 fraction Pyrolysis C5 fraction is mainly from naphtha or other heavy cracking raw materials steam cracking by-products to ethylene, generally accounting for about 10% of ethylene production, affected by the cracking raw material C5 fraction composition has changed accordingly, because it is rich in isoprene, metaprene, cyclopentadiene and other diolefin components have attracted much attention
。 Since 1982, when Shanghai Petrochemical Organization carried out joint research on the comprehensive utilization of carbon five, China has made great progress
in the comprehensive utilization of cracked C5 fractions for more than 30 years.

The main method
of cracking C5 fraction separation processing For cracking C5 fraction, using different fraction processes, C5 fraction products of different purities can be obtained, compared to other countries, China has not mastered the carbon five separation technology before, has been the by-product C5 fraction as a fuel direct use, and later in the former State Planning Commission highly valued and strongly supported, China has only begun to attach importance to the development and utilization
of pyrolysis C5 resources.

There are three main methods for the separation and processing of each fraction of pyrolysis C5: whole component separation, partial separation and direct utilization
.

Whole-component separation is the separation of isoprene, metaprene, dicyclopentadiene and single components from carbon five fractions; Partial separation is the separation of only some products in isoprene, metaprene, dicyclopentadiene and monoolefins from the carbon five fraction; Direct use is hydrosaturated as ethylene cracking raw material, or as a component of regulating gasoline
.

Downstream application and prospect
of pyrolysis C5 01 Main uses of isoprene isopreneThe main use of isoprene is in the rubber and fine chemical industry, in rubber applications isoprene is an important monomer of synthetic rubber, mainly used in the synthesis of isoprene rubber, styrene-isoprene-styrene (SIS) block copolymer and butyl rubber and other industries
.
The consumption of isoprene in the rubber industry accounts for 77.
4%
of the annual production of isoprene.

The application of isoprene in the fine chemical industry is mainly reflected in two aspects: first, methyl heptenone, vitamin E, linalool finally synthesized linaloate and other flavors and fragrances; The second is the synthesis of high-efficiency and low-toxicity pesticide pyrethroid insecticide intermediate cardia ester
by isopentenol.

Application prospects of isoprene According to the latest research progress, isoprene and polybutadiene can be synthesized into a random copolymer: butadiene/isoprene rubber; This random copolymer has special properties different from homopolymer (isoprene rubber and cis-butadiene rubber) properties, this rubber not only has excellent fatigue resistance, cold resistance, tear resistance, but also has good dynamic mechanical properties, wear resistance, wet slip resistance, etc.
, has not yet achieved industrial production, but has a good application prospect.

02 The main use of m-pentadiene m-pentadiene M-prene is currently mainly used in the production of C5 petroleum resin and curing agent methylhydrophthalic anhydride (including methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride); In addition, it can also produce: m-prene concentrate resin, specific high content monoolefin modified m-pretadiene concentrate resin, aromatic modified meta-prene concentrate resin, terpene modified meta-prene resin, aromatic and terpene modified meta-prene resin, etc.
; C5 petroleum resin has the characteristics of low acid number, good miscibility, water resistance, ethanol resistance and chemical corrosion resistance, and also has good adjustment viscosity and good thermal stability, and is widely used in rubber and adhesive tackifiers, coatings, road sign paints, inks, papermaking and other industries
.

M-prene can also produce methylhydrophthalic anhydride, methyl tetrahydrophthalic anhydride and methylhexahydrophthalic anhydride in methylhydrophthalic anhydride are liquid organic anhydride epoxy resin curing agents with excellent performance; Hydrated anhydride curing agent combined with low viscosity epoxy resin can form a cured substance with low viscosity, good impregnation, long service life and good comprehensive electromechanical properties, which is the preferred raw material for electronics, electrical industry and transformer casting products; Among them, methylhexahydrophthalic anhydride is also especially suitable for outdoor places such as light-emitting diodes, special-purpose capacitors, ignition coils, sports equipment and other epoxy resin curing fields
with UV resistance and good moisture resistance.

Application prospects of meta-prene Domestic enterprises produce C5 petroleum resin, mostly for the removal of most of the remaining C5 fraction after the removal of cyclopentadiene to produce mixed C5 petroleum resin, its quality and meta-prene petroleum resin is obviously different, with the continuous development of China's automotive industry and consumption upgrading background, the domestic demand for high-grade C5 petroleum resin and outdoor advanced curing agent will gradually expand, while increasing the demand for meta-pentadiene, in the current domestic production can not meet the demand, It is bound to further stimulate the increase
in imports.

03 The main uses of cyclopentadiene / dicyclopentadiene cyclopentadiene / dicyclopentadiene Due to the activity of cyclopentadiene (CPD) itself and the characteristics of process preparation, the industry generally first dimers cyclopentadiene into dicyclopentadiene (DCPD), and then depolymerizes or repolymerizes to obtain cyclopentadiene or dicyclopentadiene of various purities, according to its purity can be divided into polymerization grade (mass fraction≥ 99%), ethylene propylene rubber (EPDM) grade (95% ≤ mass fraction≤ 99%), polyester grade (80% ≤ mass fraction ≤85%), low purity grade (68% ≤ mass fraction ≤80%)
.

Unsaturated resin is a widely used thermosetting resin, generally produced by the polycondensation reaction of diacids and diols, linear polymer compounds with ester bonds and unsaturated double bonds, according to the functional use on the one hand can be used as a matrix material, through glass fiber reinforcement to make composite materials, used in wind power energy, rail transit, green building, lightweight engineering, medicine and other fields; On the other hand, it can be mixed with inorganic fillers to make non-reinforcing materials, which are used in artificial stone, coatings, casting crafts and other fields
.

The application of dicyclopentadiene in unsaturated resin is mainly to partially replace phthalic anhydride modified unsaturated polyester resin, and the amount of styrene modified by DPCD is reduced by 10% compared with traditional unsaturated polyester resin, which can also improve the heat resistance and corrosion resistance of the resin while reducing production costs, especially in the air dryness and flexural strength; Compared with ordinary petroleum resin, dicyclopentadiene (DCPD) hydrogenation resin has unsaturated bonds disappeared after DCPD hydrogenation, increased chemical stability and retained the cyclic structure, which is easy to form molecular entanglement with rubber in the matrix polymer, and has relatively suitable adhesion with polar and non-polar materials; Especially suitable for ready-to-use disposable sanitary materials, such as food packaging supplies, disposable diapers, pressure-sensitive adhesives, women's sanitary napkins, etc
.

EPDM rubber is one of the three major synthetic rubber varieties in the world, which is widely used in the field of wire and cable, auto parts, waterproof membrane and other rubber miscellaneous parts
.

Future prospects for cyclopentadiene/dicyclopentadiene

In 2018, China's production capacity of dicyclopentadiene through cracking C5 fractions was about 445,000 tons, with an output of about 268,000 tons; bicyclic unsaturated resin consumed about 171,000 tons of dicyclopentadiene, accounting for about 64%; DPCD hydrogenated petroleum resin consumes about 84,000 tons of dicyclopentadiene, accounting for about 31%; The ethylene describene (ENB) industry consumes about 07,700 tons of dicyclopentadiene, accounting for about 3%; In addition, about 7,500 tons of dicyclopentadiene produced by export pyrolysis of C5, accounting for about 3%.

At present, the domestic demand for DCPD hydrogenated petroleum resin reaches 400,000 tons per year, from 2015 before there is no domestic manufacturer to produce DCPD hydrogenated resin, to 2018 100,000 t/a production capacity, the average annual growth rate is about 3%, in the current domestic annual demand of about 400,000 tons stimulated, it is expected that DCPD hydrogenated petroleum resin production capacity will increase at a 5% growth rate in the next three years , which has recently further driven the demand
for dicyclopentadiene (DPCD).

The C9 fraction by-product of the ethylene plant, referred to as pyrolysis C9
.
Pyrolysis of C9 is the fraction remaining after the cracking of liquid raw materials such as naphtha or light diesel oil, and the separation of C5 fraction and C6-C8 fraction from the pyrolysis by-product, usually accounting for 10% ~ 15%
of the total ethylene production.

Source of pyrolysis of C9

First, the by-product of steam cracking to produce ethylene, containing a large number of unsaturated components, about 150 kinds of components Second, reforming C9, xylene bottom oil
of the refinery reforming unit.
The first route of cracking C9 processing and utilization is to separate a variety of products through rectification, which can separate DCPD, dimethylcyclopentadiene (DMCPD), separate alkyl benzene fractions to hydrogenate to produce high aromatic solvent oil and gasoline blending components, separate styrene and indene fractions and repolymerize them into petroleum resins, separate recombinants to produce fuel or bitumen, and separate naphthalene and methylnaphthalene; The second is first polymerization and then separation and hydrogenation, the monoolefin component in the C9 fraction polymerizes to separate the substances that have not been reacted and the components with low boiling point to obtain petroleum resin, and flash oil will be produced in the production of petroleum resin at the same time, and the high aromatic solvent oil and gasoline blending components are obtained by hydrogenation; The third is the direct hydrogenation to produce gasoline blending components
.
The main use of C9 is to crack C9 fractions with about 150 kinds of chemical components, containing a large number of olefins, easy to polymerize, high colloidal content, component dispersion, low content of each component, boiling point is very close, and the use of single components is
difficult.
From the perspective of synthetic chemistry, the composition can be divided into two categories: active components (styrene, indene, dicyclopentadiene, etc.
), polymerized into petroleum resin, or hydrogenated as inactive components; Inactive ingredients (alkyl benzene and polycyclic aromatic hydrocarbons such as indene, xylene, naphthalene, methylnaphthalene, etc.
) as aromatic solvents, or paraxylene (PX) production raw materials
.

The utilization of C9 mainly has the following aspects: 01 C9 petroleum resin production C9 petroleum resin is a thermoplastic resin produced by the by-product of petroleum cracking C9 fraction, through pretreatment, polymerization reaction, distillation and other processes.
It is not a polymer, it is an oligomer
with a molecular weight of 300~3000.
Because it has a low acid number, good miscibility, water resistance, chemical resistance, and stable chemical properties, it is widely used in coatings, paints, rubber and other industries
as accelerators, regulators and modifiers.
However, the produced petroleum resin is darker in color, the product performance is insufficient, and it needs to be hydrotreated
.
Hydrogenation is difficult and costly, and the technology needs to be improved
.
02The DCPD content in the C9 fraction produced by high-purity dicyclopentadiene (DCPD) is generally above
30%.
High-purity DCPD is mainly used in fine chemicals, such as polydicyclopentadiene materials, optical plexiglass materials, epoxy resins, and metal-organic compounds, chemical intermediates, preparation of ferrocene, chemical additives, adamantane, glutaraldehyde, ethylene propylene rubber, preparation of high-energy fuels and other products
.
03 Most enterprises in the production of high-quality aromatic hydrocarbon solvents first synthesize petroleum resin, or after extracting DCPD, after consuming most of the active components, the remaining components are hydrogenated in the first and second stages to make solvent oil
。 Or after cutting the components above C9, removing the gum, reducing the content of arsenic, sulfur, etc.
, after a period of hydrogenation, after saturating most of the olefins, it can be used as a high-octane gasoline blending component; After the second stage of high-temperature hydrogenation to remove impurities such as sulfur and remaining olefins, it can be used as high aromatic solvent oil and extracted aromatic hydrocarbons
.
Due to the large amount of olefins, it is easy to polymerize, the arsenic and gum content are high, and it is difficult to hydrogenate, and it needs to be cut through the process to remove the recombinant components, and this will lose about 30% of high-value aromatics
.

04Extract high value-added one-component components such as indene, xylene, naphthalene, methylnaphthalene, etc.
, and the utilization
of carbon nine tar.

Conclusion C4, C5, C9 are valuable resources for the comprehensive utilization of chemical industry, which has gradually shifted from the initial mixed utilization to the separation of single components, and has developed
in the direction of preparing refined, diversified and high-end products.
Large domestic and foreign enterprises have also included the development of C4, C5 and C9 industrial chains as part of their
global strategies.
At present, typical C4 and C5 separation and utilization related technology developers include ExxonMobil, Lyander Basel, IFP, BASF, UOP, Sinopec, Asahi Kasei, Ruion, PetroChina, Lummus, etc
.
In general, there is still a big gap
between the advanced level of China and foreign countries.
Taking C5 as an example, isoprene has achieved large-scale production, the industrial chain is relatively complete, the production concentration is high, and the downstream market development is better
.
The downstream of cyclopentadiene and metaprene are mainly private enterprises and foreign-funded enterprises, with low production concentration and low-end products
.

Under the background of the continuous change of global petrochemical raw material supply form and the imminent development of China's chemical industry, the C4, C5 and C9 product chains have gradually been pushed to the key competitive areas of
the petrochemical industry.
In the future, how enterprises design new C4, C5 and C9 resource product solutions, and how traditional petrochemical enterprises optimize the industrial structure, are of great significance
for enhancing the lasting competitiveness of enterprises, improving efficiency and adding value of the entire industry.
The development of C4, C5 and C9 industries will also bring great opportunities
to related engineering technology and equipment suppliers.
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