An Innovative Approach S.K. Goel BPCL Mumbai Refinery 1 Hydrogen - - PowerPoint PPT Presentation

1

Hydrogen Unit debottlenecking – An Innovative Approach

S.K. Goel BPCL Mumbai Refinery

International Conference on Refining Challenges & Way Forward

Hydrogen Unit Process Details

3

Need for Innovation

Unit Capacity 49,000 MTPA (148.5 MTPD) Plant Commissioned In August 2005. Hydrogen availability low because of reduced thruput, impacting HSD Production Issues – Low Pre-reformer temperature, close to hydration limits This required lower firing in bottom section of reformer, which in turn caused higher skin temperature in upper sections of the reformer.

4

Bottlenecks

Unit was revamped in 2008 to include CRU off gas as part

• f the feed. This helped to some extent to increase pre-

reformer temperature Problem aggravated with switch over reformer feed from naphtha to natural gas, since the reformer firing

• reduced. There was a sharp drop in Pre-reformer

temperature. There were 5 tube failures, causing expensive shut down’s. Unit was operated at reduced throughput & tube max skin temperature limited to 945 deg C.

5

Possible solutions

Licenser suggested to augment heat transfer area in reformer convection section. This was not found feasible, due to space limitations in the unit & needed a major revamp. Other Licensers suggested duct firing or a convective

• reformer. These were capital intensive & also needed

higher energy consumption.

6

BPCL Innovation

The innovation emerged from the following thought process.

Can we use steam superheat space for process pre-heat? or Can we augment process pre-heat instead of steam superheating to such a high degree, which was really not needed.

A closer look at the process revealed that part of lower temperature steam from feed heat exchanger can be exported directly, which would augment process pre- heat. The concept was agreed by Process Licenser, who supported for finalizing the process Design.

7

NHGU Prereformer Temperature Profile 410 430 450 470 490 510 20 40 60 80 100 % Catalyst Bed

Temperature

Naphtha feed case

Prereformer Temperature Profile

N H G U P re re fo rm e r Te m p e ratu re P ro file 4 1 0 4 3 0 4 5 0 4 7 0 4 9 0 5 1 0 2 0 4 0 6 0 8 0 1 0 0 % C ataly s t B e d

Te m p e r at u r e

N a phtha fe e d c a s e R L N G + C R U offg a s fe e d c a s e

8

Steam Network

320 °C

9

Steam Network

320 °C

10

Post Modification – Pre-reformer Bed Temperatures

410 420 430 440 450 460 470 480 490 500 510 10 20 30 40 50 60 70 80 90 100

Naphtha Case RLNG Case After Modification

11

Results Achieved

• Pre-reformer minimum bed temperature increased by 15

deg C & tube skin temperature dropped by 10 deg C

• Fuel reduction – 4 MT/D
• CRU off gas – No longer essential in the feed, thus unit

load can be increased independently during CRU shut down.

• Unit rated capacity achieved with 962 deg C max skin

temperature & natural gas feed.

The idea won BPCL Chairman’s award at Ideas 2011 Platform. This is the highest in-house award to nurture Innovation & Talent in the organization

12

Thank you