Page 186 - CW E-Magazine (30-4-2024)

Special Report Special Report

EMS-47: The strength of various cir-
ble ultra-sonic sound detectors for identi-
Energy conservation ideas for the chemical, culating absorbents or solvent is decided fi cation and early repair of the same. tion columns is decided based on many
constraints. In normal operation, it is
petrochemical and refi ning units (Part 2) based on solidifi cation possibility at EMS-51: Small capacity turbine- observed that margin exists in various
higher strength or limited by high tem-
constraints for manipulating pressure of
perature to avoid degradation or equip- driven pumps and compressors are pro- distillation column. Operation of distil-
very act of energy conservation nance based on leak test by soap solu- JOY M. SHAH ment limitation. One of the possibilities vided in design for improved reliability lation column at lowest possible pressure
is more than just common sense. I tions or Lower Explosive Limit (LEL) E-mail: shahjoym@hotmail.com of energy conservation in such system is and meet the steam balance requirement. will reduce temperature requirement and
Etell you, it is an act of patriotism – detectors; however the exercise is very to increase strength of absorbent or sol- However, it is often observed that back reduce refl ux ratio. It will reduce energy
Jimmy Carter. cumbersome and manpower-intensive. capacity of supply is limiting, such vent to operate at reduced fl ow. This will pressure turbine generates LP steam for consumption signifi cantly and also
Moreover, unapproachable locations leakage is not given focus. But it is not only save pumping energy, but save which there is no sink. Sometimes, to run improve product quality.
For reducing carbon footprint, the cannot be monitored. It is worthwhile to observed that such leakage can contrib- thermal energy for preheating of solvent. turbine using HP steam, steam is let down
fi rst step is to conserve energy and consider fugitive emission leak detec- ute up to 20-25% loss of energy in com- from Super High Pressure (SHP) header. EMS-56: When temperature diffe-
improve energy effi ciency of existing tion programme for complex chemical pressed air unless focused approach of EMS-48: Low temperature heat is Nowadays, increase in power reliability rence of top and bottom of any distillation
assets. It is possible to reduce specific energy plants using infra-red camera for moni- periodic leak detection, and survey of removed from process using circulating makes turbine-driven reliability redundant. column is not large, provision of vapour
consumption by 10-15% by improving toring, identifi cation and arresting of air, nitrogen and other compressed gas cooling water or released to atmosphere. In such cases, it will be economical and compression heat pump in place of over-
operational discipline and identifi cation leakage quickly. Although cost of these lines are taken up and repair of the In some applications, it is in millions prudent to replace steam turbines by head condenser and steam usage in its
of all low hanging fruits and execute the cameras is high, it can be paid back by same is carried out. of calories of heat. Such low level heat electric motors. reboiler can be justifi ed for signifi cant
ideas. It requires structured approach, careful regular monitoring in fi rst round can be utilised to generate work either in energy savings.
which is the energy management system. of leak detection programme. EMS-45: Standby pumps for high terms of electricity or refrigeration. One EMS-52: Multiple level steam headers
temperature service are provided with idea is application of Organic Rankine are connected by Pressure Reducing & EMS-57: Due to design margin as
In my previous article (Chemical EMS-43: Steam and condensate warm up line to avoid thermal shock Cycle (ORC) for energy recovery and Desuperheating Station (PRDS). In well as composition mismatch, many dis-
Weekly, April 23, 2024) I mentioned lines in plants are insulated. There is while start up, especially when pump is power generation. case of shortfall or surplus in any of the tillation columns are operating for better
about 40 ideas. In this article, I shall probability of corrosion under insula- multi-stage. Many pumps are provided header, stream is let down from one to product quality than design. In case there
talk about 41 which I practiced over the tion especially where there is cyclical with minimum circulation lines with RO, EMS-49: Plant is designed for auto other header. However, due to mismatch is no premium for superior quality, refl ux
years. You may check possibilities to temperature and wet atmosphere. The which ensures minimum circulation control and to certain extent feed forward, in demand-supply of any of the headers, can be optimised for quality give away of
implement at your plants. insulation gets damaged due to many through standby pumps all the time for cascade as well as sequence control. the let-down of steam from high pres- distillation column top and bottom pro-
reasons. It is observed that frequent keeping it warm. This recirculation is Advance process control (APC) is sure to lower pressure through PRDS is duct to reduce energy requirement.
EMS-41: Source and price of energy leakage gets developed in steam and loss of energy. During normal operation, normally designed and executed after taking place on continuous basis to meet
has been very dynamic in last 10 years. condensate line, leading to loss of such continuous recirculation can be start-up and stabilisation of plant opera- LP steam requirement. In such case it is EMS-58: Nitrogen is an inert gas and
A scheme which is techno-economically expensive utilities. Similarly, due to stopped by providing automation to tion. For some complex plants, APC is worth considering mini-steam turbine in is used for blanketing, conveying, inertis-
feasible few years back is found un- frequent operation of trap as well as establish fl ow as and when required. not executed due to various reasons and place of PRDS for power generation. ing and pressure control in hydrocarbon
viable due to change of source and price. moving part damage, the trap also In some of the pump applications, it is plant operates with basic controller for industry. It is an expensive utility. In some
Vice versa is also true. Therefore, it is malfunctions, leading to loss of expen- possible to stop continuous warm up years. It is essential to give priority to EMS-53: In large vacuum columns, dry applications, pure nitrogen could be
essential to review position periodically. sive steam. Steam and condensate lines circulation and pump was warmed up APC to drive process to optimum opera- multi-stage ejector is provided. Steam replaced by available waste carbon diox-
One of the methods is to carry out perio- normally cannot be isolated, therefore just prior to start-up. ting points all the time. It is expected consumption in such ejector can be ide/reactor off gas after its drying.
dic energy audit of facilities to identify leaks are arrested by online sealing. that 2-3% energy saving can be achieved very high, if inert loading is more. It is
energy saving opportunities and prepare Prior to annual turnaround of any plant, EMS-46: Deaerator consumes Low by APC. observed at some locations that replacing all EMS-59: Converting normal lights
short-term and long-term road map for survey of leakage and severely corroded Pressure (LP) steam to increase tempera- or any one stage using vacuum pump can by LEDs reduces electricity consumption
energy conservation drive. lines and meticulous planning of repair ture of demineralised water (DMW). In EMS-50: Manual valves, control reduce steam consumption substantially signifi cantly. New installations also must
of these areas can bring signifi cant loss case low level heat is available, deaerator valves as well as pressure relief valves for energy savings. consider LED lights. However, old industry
EMS-42: Refi nery and petrochemi- reduction and energy saving. is operated at high pressure/temperature; can start passing after frequent opera- installations, as well as commercial
cal plants are very complex and have however it will reduce heat recovery tion. There are hundreds of such valves EMS-54: Azeotrope of any chemical buildings, lag in this initiative. Replace
many valves with gland packing, fl anges EMS-44: Compressed gas/air is from fl ue gas and may increase fl ue gas in a complex plant for pressure control can reduce latent heat of vaporisation. It standard lighting fi xtures by LEDs on
with gaskets, as well as rotary equip- used in process plants at various loca- temperature. In order to recover fl ue and regulation. Normally, leak or passing also reduces boiling point in many cases. priority in all industrial and commercial
ment seals to arrest any leakage. These tions. Over a period of time, leakage gas heat to maximum extent, deaerator of valves is not visible, although In some applications, it is observed that installation.
are prone for minor diffusion of line of compressed gas from union, joints, can be operated at low temperature and experienced operators can recognise it converting conventional distillation to
material and in case of wear and tear and pinholes due to corrosion can take low pressure too without compromise in based on change in sound pattern or visible Azeotropic distillation by addition of EMS-60: Public installation of solar
or aging, rate of diffusion and leakage place. Valve gland leakage leads to integrity of oxygen removal. It is possi- sweating on pipeline downstream of entrainer can reduce steam/heat require- lights are considered in area where
to atmosphere increases. Some com- increase in consumption of the utility ble to optimise deaerator temperature valve. It is possible to monitor leak and ment signifi cantly. electricity is not available. Due to risk
panies carry out accounting of fugitive carried. At many locations, utility point and pressure based on free heat available passing of control valves, safety valves of theft and maintenance requirement of
emission loss and periodic mainte- valves are not closed tightly. Till the in fl ue gas and cost of LP steam. and manual valves using fi xed or porta- EMS-55: Design pressure of distilla- battery, it is avoided in public places in

186 Chemical Weekly April 30, 2024 Chemical Weekly April 30, 2024 187

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