| Cleaner Production Audit of a Refinery Process | China | 1993 | Full Scale |
Background
Refining is one of the processes enterprises of the Beijing Yanshan Chemical Corporation (BYPC) with 5800 employees. Founded in 1969 and located 50 km southwest of Beijing, China, the refinery has 16 processing units including crude distillation and FCC which have a total throughput capacity of 6.6 million tons of crude oil annually. The total assets of the enterprise amount to 1.46 billion RMB and a revenue of 3.144 billion RMB with a tax of 740 million RMB paid in 1993. The product line of the refinery includes gasoline, diesel, kerosene, lubes and wax.
The refinery produces large amounts of industrial wastes and is listed in '3000 Most Heavily Polluting Companies' in China. The refinery participated in the Sino-Norwegian cleaner production program in China to obtain economic benefits and to protect the environment. They strove for a sound use of resources and energy, a reduction in energy and raw materials consumption, and an increase in energy efficiency.
Cleaner Production Principle
Recovery, Reuse and Recycle; Housekeeping; Material substitution; Process modification
Cleaner Production Application
The FCC unit 2 (FCCU2) is one of the most important process units in the refinery. It was put into operation in Oct. 1983 and was modified to process vacuum residual (at a capacity of 800,000 tons feed a year) in 1985. There are three unit operations in the unit including reaction, fraction and absorption/stabilization desulfurization.
The feeds to the unit are heavy AGO and VGO which are cracked from catalyst involvement in the reactor, out of which comes lighter oil which goes through the distillation tower and stabilizer to produce the gasoline and diesel. The spent catalyst is regenerated and reused after cooking process.
Waste stream information:
Cleaner Production Options
After screening cleaner production options generated by the employees, a total of 28 cleaner production options were identified and evaluated. Ten of the options (Class A) were implemented immediately. Fourteen of the options (Class B) may result in a good economic return. After analyzing the fourteen options, three of the options (Class B) underwent a feasibility analysis and will be implemented. The other eleven Class B options are listed in a long-term plan. Four options that are difficult to implement will be put on file for future studies.
Housekeeping (Class A)
Technical improvement (Class B)
Research and Development (Class C)
Stage of Development
Ten Class A options were implemented immediately in 1995
For Class B options, three will be implemented in 1996. The other eleven will be implemented after 1996.
Environmental and Economic Benefits
Changes in the consumption of energy
Before CP program, steam consumption was 22.0 tons/h. After implementing A options, steam consumption was still 22.0 tons/h. After implementing 3 of the Class B options, steam consumption was 12.0 tons/h. After implementing the remaining eleven Class B options, steam consumption was reduced to 11.0 tons/h.
Changes in the consumption of water
Before CP program, soft water consumption was 17.0 tons/h. After implementation of the A options, soft water consumption was 16.2 tons/h. After implementing 3 of the Class B options, soft water consumption was 11.2 tons/h. After implementing the remaining eleven Class B options, soft water consumption will be reduced to 11.0 tons/h.
Changes in the waste streams
After implementation of the A class options, waste water discharge was reduced 13.2 thou. tons/yr. amounting to 9% of all waste water discharge. The COD discharge of waste water will be reduced 3.1 tons/year amounting to 32% of the total. The solid waste will be reduced 50 tons/year amounting to 10% of total.
Waste and Pollutants after Implementing Options
Profits from no investment options :
After implementation of Class A, waste water discharge will be reduced 13.2 thousand tons/yr. amounting to 9% of all waste water discharge. The COD discharge of waste water will be reduced 3.1 tons/year amounting to 32% of the total. The solid waste will be reduced 50 tons/year amounting to 10% of the total.
Profits from investment :
If the unit invests 10.15 mill. RMB on a cleaner production project, annual net savings will be 6.88 mill. RMB. The steam consumption will be reduced 77 thousand tons/year amounting to 45.5% of total. The soft water will be reduced 3.84 tons/year amounting to 29.4% of total.
Steam and energy consumption will be reduced and no new pollution would occur after option No. 22 is implemented. The flue gas can still be reused for gas expander or alkaline residual disposal.
After option No. 23 is implemented, the water pollution source will be eliminated by recycling soft water and reducing soft water consumption. No new pollution would occur.
After option No. 24 is implemented, the carbon dioxide in the flue gas reacted with the hydroxides in the alkaline residual to yield carbonate. And the pollutant in the flue gas is absorbed by alkaline residuals which is sent to the water treatment plant.
Investment Costs
Option 22. Recovering heat in regenerator flue gas by boiler
| Capital investment | (RMB) |
| Process equipment | 7,000,000 |
| Site preparation | 1,000,000 |
| connection to utility | 1,000,000 |
| site facilities | 1,000,000 |
| Total | 10,000,000 |
Option 23. Improving air cooling system to recover soft water
| Capital investment | (RMB) |
| Process equipment | 70,000 |
| connection to utility | 10,000 |
| construction & installation | 20,000 |
| Total | 100,000 |
Option 24. Neutralizing waste alkali with flue gas regenerator
| Capital investment | (RMB) |
| Process equipment | 20,000 |
| connection to utility | 10,000 |
| construction & installation | 20,000 |
| Total investment | 50,000 |
Operational and Maintenance Costs(RMB)
Option 22. Recovering heat in regenerator flue gas by boiler
| Total annual savings | 9,200,000 |
| Net savings | 7,810,000 |
Option 23. Improving air cooling system to recover soft water Saving on annual operation 69,100
| Net savings | 59,100 |
Option 24. Neutralizing waste alkali with flue gas regenerator
| Saving on annual operation | 30,000 |
| Net savings | 25,800 |
Cleaner Production Benefits
Profits with no investment :
After the implementation of cleaner production audit project, the workshop had a before-tax profit of 804,000 RMB per year. Waste water reduction at 13,200 tons/year amounted to 9% of total consumption. COD reduction in waste water was 3.1 tons/year and amounted to 32% of total consumption. Solid waste reduction was 50 tons/year and amounted to 10% of total consumption. Waste treatment fees were reduced by 0.79 million RMB.
Profits from investment :
If the workshop invests 10.15 million RMB on cleaner production projects, annual after-tax profit is estimated at 6.88 million RMB. Steam reduction will be 77,000 tons/year amounting to 45.5% reduction of total consumption. The soft water reduction will be 38,400 tons/year amounting to 29.4% of total consumption.
Investment Analysis
Payback Time
Option 22. Recovering heat in flue gas regenerators by boiler
| Payback period | 1.28 years |
| Internal Rate of Return (IRR) | 77.9% |
Option 23. Improving air cooling system to recover soft water
| Payback period | 1.69 years |
| IRR | 58.5% |
Option 24. Neutralizing waste alkali with flue gas regenerator
| Payback period | 1.94 years |
| IRR | 50.8% |
Constraints
None mentioned
Contacts
Review Status
This case study was submitted to UNEP IE by the Sino-Norwegian Cleaner Production Program. It was edited and formatted for the ICPIC diskette in May 1997.
Subsequently the case study has undergone a technical review by Dr Prasad Modak at Environmental Management Centre, Mumbai, India, in September 1998.