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Energy Audit Project of Gas Refinery BidBoland
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Considering the exact amount
of needed energy for gas sweetening in planning and in the satisfactory amount within
international scale, a more efficient use of energy in a gas refinery commences
with a reduction of material loss and then continues with an optimization of process,
a promotion of technology, load and energy management, an increase in the efficiency
grade of equipment, with an alteration or exchange or similar cases. Energy auditing
as the beginning point for reaching the optimal consumption in a gas refinery bears
the duty of recognizing the amount and the method of energy use in different
consumers and also the determination of intensity coefficients so that it can suggest
strategies for curing the system. So in a first step of the energy audit of refinery
project, the current condition and the optimal state of the refinery are determined
and then some strategies are prepared so that the current state can reach the optimal
state.
In this project, the condition
of different parts of the refinery and its major equipments concerning the different
energy consumers have been studied by the aid of case study documents, reports,
interviews with the refinery staff, and then the real conditions of function have
been calculated through field activities. Then the condition of energy consumption
in refinery and other units has been determined quite carefully.
The Balance of Obtained Germ and Energy in One of the Refinery Units
Energy Consumption
Intensity determined for Sweetening Units and Planning Conditions
As examples, we can mention
some of the following factors: Determination of extra air percentage in boilers
and kilns and the waste amount resulting from that; determination of utilization
conditions of thermal transformers; operational conditions of tower such as condensation
cycle, percentage of gas to air and the number of transformation units; the conditions
of transformer utilization and the conditions of power transmission; problems such
as lack of setting the voltage level, existence of harmonic and lack of balance
in the network and …. Such activities demonstrate the required activities for promoting
the productivity level quite clearly.
Based on the studies and
measurements, which have been carried out and with the aid of technical possibilities
and economical assessments and determining the period of investment return, methods
of passing from the current level to the optimal level are offered. These plans
have been suggested to increase the energy consumption efficiency and to decrease
the energy consumption intensity in system and under the title of energy saving
opportunities. These plans are prepared based on the studies of audit group in refinery
in order to improve the condition systems. Each plan offers a new approach for a
better function and more efficient consumption in each special part of the refinery.
Among the most important plans in this project is the project of investigation the
problem of energy recycling in boilers by installing air and water pre-warming machine,
exchanging the solvent in sweetening units and recycling of hydraulic energy from
dirty amine current and the exchange of water purification system. As far as it
costs expensive and it requires the implementation of new machinery to realize such
plans, it has been tried to carry out the economical calculations, saving assessments,
which results from the project, and finally the investment return so that the managers
can take their decisions based on these amounts.
There will be a description
of saving opportunities of energy in the following:
1. Optimizing the exploitation
situation in sweetening units: simulation of sweetening units and investigating
the results of setting the process parameters such as density and power of amine
loading, temperature in different parts of the process and the operation way of
amine transformer to amine and … in both the intended planning and the optimal mood.
The results for the sweetening unit, which have come true with a small change in
exploitation conditions, are as following:
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Amine in cycle: 232100 kg/hr
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Density: 15,78 Wt%
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Loading: 0.3929 mol/mo
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Debby of sour gas: 142504 kg/hr
The savings per month in
this plan amounts to 127.680.000 Rials.
2. Solvent exchange in sweetening
units: an analysis of the results of solvent exchange between two sweetening units
of 300 and 400 and the determination of savings resulting from the plan and their
influence on intensity coefficient of energy consumption are as follows:
- Analysis condition: 300 and 400 sweetening
- Energy saving per month amounts to 177.100.000
Rials.
3. Hydraulic energy recycling
from dirty amine current: analysis of influences of recycling system; opting for
providing pump and hydraulic energy and its usage for providing clean amine pressure;
opting for appropriate equipment and providing pumps; economical analysis of the
plan and finally determining its efficiency grade in different moods of usage of
the saved energy and the way of providing the remained energy.
- Energy saving per year for each sweetening unit amounts to
1.680.000.000 Rials.
- Return period of this plan amounts to 8.6 months.
4. The exchange of production
system for distillated water:
Distillated water in the
gas refinery Bid Boland is produced with the evaporation method. In this plan, after
having considered different methods of producing water, the reversed osmosis was
recognized as an appropriate method. The current system was changed by the osmosis
one. The reverse osmosis plan was planned to show the economical aspect of the idea,
then the saving amount of the period and finally the return period was determined.
- The monthly saving amount of this plan amounted 135.000.000
Rials.
- The return period of this plan amounts 17 months.
5. Error removing from steam
turbo generators and producing LP steam and electricity
- entering steam to unit 300 by pressure-breaker valve 22 ton/hr
- entering steam to unit 400 by pressure-breaker valve 25 ton/hr
- Obtainable energy 3.7 MW
- The monthly saving in this plan amounts to 340.725.600 Rials
6. Energy recycling in boiler
with the aid of water and air pre-warmer:
During this plan, the recycling
of thermal energy from the exiting exhaust of the boilers in refinery has been studied
and the amount of recyclable energy, the required thermal level, the effects of
recycling on the function of boilers and the amount of saving have been determined
through different simulations.
- The augmentation of temperature from 104 Centigrade to 132
Centigrade
- Monthly savings on energy amounts to 48.000.000 Rials.
- Return period of the plan amounts 24 months.
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