UTILIZATION OF NORMAL CARBON 4 (NC4) RECYCLE STREAM FOR SECONDARY AND TERTIARY PRODUCTS

Abstract

Certain embodiments are directed to an integrated process for the production of Maleic Anhydride (MAN), 1,4 Butanediol (BDO), Gamma-ButyroLactone (GBL), and PolyButylene Terephthalate (PBT) utilizing NC4 rich stream from a recycle stream after or before processing by a Total Hydrogenation Unit (THU).

Claims

1. A method of forming products from C4 hydrocarbons in an olefin producing plant; the method comprising: receiving, from a hydrogenation unit, a hydrocarbon stream comprising primarily C4 hydrocarbons; contacting, in a reactor unit, the hydrocarbon stream with a catalyst under reaction conditions to form maleic anhydride; and converting, in one or more finished product units, at least some of the maleic anhydride to one or more of: 1,4 butanediol (BDO), gamma-butyrolactone (GBL), or tetrahydrofuran (THF), wherein the hydrogenation unit is in fluid communication with the reactor unit and the reactor unit is in fluid communication with the one or more finished product units.

2. The method of claim 1, wherein the feed stream for the hydrogenation unit is a side product stream received from a butane separation unit.

3. The method of claim 2, wherein the feed stream for the butane separation unit is a side stream received from a methyl tertiary butyl ether (MTBE) production unit.

4. The method of claim 3, wherein a feed stream for the MTBE production unit is received from a selective hydrogenation unit (SHU).

5. The method of claim 4, wherein a feed stream for the SHU is received from a butadiene production unit.

6. The method of claim 5, wherein a feed stream for the butadiene production unit is received from a debutanizer unit coupled to steam cracking unit.

7. The method of claim 5, wherein a feed stream for the butadiene production unit is received from a steam cracking unit.

8. A method of forming products from C4 hydrocarbons in an olefin producing plant that utilizes a steam cracker unit; the method comprising: receiving, from a hydrogenation unit, a hydrocarbon stream comprising primarily C4 hydrocarbons, wherein the primary C4 hydrocarbon in the hydrocarbon stream is n-butane; contacting, in a reactor unit, the hydrocarbon stream with a catalyst under reaction conditions to form maleic anhydride; converting, in one or more finished product units, at least some of the maleic anhydride to one or more of: 1,4 butanediol (BDO), gamma-butyrolactone (GBL), or (THF), wherein the hydrogenation unit is in fluid communication with the reactor unit and the reactor unit is in fluid communication with the one or more finished product units; and reacting at least some of the BDO to form polybutylene terephthalate (PBT).

9. The method of claim 8, wherein the feed stream for the hydrogenation unit is a side product stream received from a butane separation unit.

10. The method of claim 9, wherein the feed stream for the butane separation unit is a side stream received from a methyl tertiary butyl ether (MTBE) production unit.

11. The method of claim 10, wherein a feed stream for the MTBE production unit is received from a selective hydrogenation unit (SHU).

12. The method of claim 11, wherein a feed stream for the SHU is received from a butadiene production unit.

13. The method of claim 12, wherein a feed stream for the butadiene production unit is received from a debutanizer unit coupled to steam cracking unit.

14. The method of claim 12, wherein a feed stream for the butadiene production unit is received from a steam cracking unit.

15. A method of forming products from n-butane in an olefin producing plant that utilizes a steam cracker unit; the method comprising: receiving, from a hydrogenation unit, a hydrocarbon stream comprising primarily n-butane, wherein no portion of the hydrocarbon stream is recycled to the steam cracker unit; contacting, in a reactor unit, the hydrocarbon stream with a catalyst under reaction conditions to form maleic anhydride; converting, in one or more finished product producing units, at least some of the maleic anhydride to one or more of: 1, 4 butanediol (BDO), gamma-butyrolactone (GBL), or (THF), wherein the hydrogenation unit is in fluid communication with the reactor unit and the reactor unit is in fluid communication with the one or more finished product units; reacting at least some of the BDO with purified terephthalic acid (PTA) to form polybutylene terephthalate (PBT); and converting at least some of the BDO to one or more of: N-methylpyrrolidone (NMP), M-ethylpyrrolidone (NEP), or 2-pyrrolidone.

16. The method of claim 15, wherein the feed stream for the hydrogenation unit is a side product stream received from a butane separation unit.

17. The method of claim 16, wherein the feed stream for the butane separation unit is a side stream received from a methyl tertiary butyl ether (MTBE) production unit.

18. The method of claim 17, wherein a feed stream for the MTBE production unit is received from a selective hydrogenation unit (SHU).

19. The method of claim 18, wherein a feed stream for the SHU is received from a butadiene production unit.

20. The method of claim 19, wherein a feed stream for the butadiene production unit is received from a debutanizer unit coupled to steam cracking unit, or directly from a steam cracking unit.

Description

DESCRIPTION OF THE DRAWINGS

[0019] The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of the specification embodiments presented herein.

[0020] FIG. 1. Illustrates a schematic of one embodiment of the invention diagramming integrated process that minimizes inefficiency in processing a steam cracking product stream. Abbreviation used include: H.sub.2=hydrogen; MeOH=methanol; MTBE=methyl tertiary butyl ether; PTA=purified terephthalic acid; PBT=polybutylene terephthalate; MAN=maleic anhydride; BDO=1,4 butanediol; GBL=gamma-butyrolactone; THF=tetrahydrofuran; SHU=selective hydrogenation unit, and THU=total hydrogenation unit.

DESCRIPTION

[0021] The full utilization of recycle streams has been always a major target for optimization. The elimination of recycles, in general, always improves the efficiency of the recipient unit opening the door for increasing actual capacity and better technical and operational performance. The processes, systems, and methods described herein utilize the NC4 recycle stream for secondary and tertiary production, which increases efficiency in the utilization of infrastructure. In certain aspects the utilization of NC4 to eliminate/minimize the recycle option in the steam crackers is targeted and used for production of secondary and tertiary products. In certain aspects these multiple products from NC4 increases production and expands products. Production can be increased by increasing available volumes to greater than 10 kilo-ton per hour (KTPH) of rich NC4 stream. The NC4 stream can be provided by a THU using the steam cracker recycle stream as feedstock for a maleic anhydride (MAN) unit, with an estimate of around 44,000 ton/year of MAN and with production of 60.14 tons/hour of high pressure steam (HPS) at 725 psig leading to 5.5 Ton/Hour fuel savings. This HPS production from MAN unit can reduce fuel consumption and utilization of two boilers.

[0022] The NC4 stream can be augmented by including or integrating other appropriate systems, processes, and appropriate recycle or side-product streams. These other streams can be obtained from other units working in parallel or in series, as well as collecting recycle streams from other facilities. As shown in FIG. 1, an alternate or additive NC4 source can be derived from a steam cracker indirectly coupled to a MAN unit by selecting a number streams or side products from a series of processing units. The steam cracker is coupled to a debutanizer that is coupled to a butadiene unit. The butadiene unit is indirectly coupled to the MAN unit via a selective hydrogenation unit (SHU), MTBE conversion unit, a butane separation unit, and the THU upstream of the MAN unit. This additional volume could increase the proposed Maleic Anhydride plant production capacity up to 64,000 ton/year with 87.47 tons/hour of HPS at 725 psig, resulting in 8 ton/hour fuel savings. It is estimated from operational data that one ton of fuel gas from reboilers produces approximately 11-12 tons of HPS (100 bar).

[0023] In another embodiment a process, which can be integrated with other processes or systems, can be used where hydrogenated olefins from C4 hydrogenation unit is recycled and co-cracked in the steam cracker unit. In certain aspects a NC4 stream from the THU can be introduced into a MAN unit. The MAN unit can provide for a feedstock for: (i) an established BDO/THF/GBL unit, or (ii) partial or total BDO feed for a PBT unit that together with a PTA stream can be used as feedstocks for PBT production. Utilizing the design described herein integration between a steam cracker complex and purified terephthalic acid (PTA) is achieved. MAN (Maleic Anhydride Technology). Utilization of crude MAN form the MAN unit can be a source of feedstock for downstream process and systems.

[0024] An estimated 50% of world maleic anhydride output is used in the manufacture of unsaturated polyester resins (UPR). Chopped glass fibers are added to UPR to produce fiberglass reinforced plastics which are used in a wide range of applications such as pleasure boats, bathroom fixtures, automobiles, tanks and pipes.

[0025] GBL and BDO are widely used industrial chemicals serving as critical ingredients in many different products and applications. GBL offers excellent solvent qualities with low toxicity and diminished environment concerns. GBL is involved in the manufacture of products including hospital supplies, beverage filtration and purification aids. GBL is also used for applications including circuit board cleaning in the electronics and high technology industries; the production of herbicides; and as a processing aid in the production of vitamins and pharmaceuticals. While there are solvent applications for GBL, the majority of the GBL manufactured is used by industrial companies as an intermediate in the manufacturing process of other chemicals.

[0026] THF is a moderately polar aprotic solvent. It finds its application as a solvent for adhesives, lacquers, printing ink and unvulcanized rubber. It is used as a chemical intermediate in the preparation of polytetramethylene glycol; butyrolactone; succinic acid; adipic acid; 1.4 butanediol diacetate; and tetrahydrothiophene.

[0027] PTA is the main raw material for polyethylene terephthalate (PET) and polyester fibers, and is produced by oxidizing paraxylene. Some of the most common uses of PET include food, beverage, and consumer good packaging. Polyester fibers are used mainly in rugs, clothing, furniture and industrial applications, as well as other consumer products.

[0028] By using the process and design described herein each of these secondary or tertiary products can be produced in a more efficient and cost effective manner. Each unit will comprise the necessary devices, reactors, and apparatus for performing the process assigned to that particular unit as well as including all valves, piping, tubing, pumps, etc. needed to introduce feed streams and move products, side-products, or recycle streams to and from units in order to perform the processes described herein.