Energy and Water Conservation Ideas in Chemicals, Petrochemicals and Refinery Sectors - 3 of 3

This article was published in IIChE News Letter - August 2024, Vol 16, Issue 2 under the series of Climate change and Sustainable Manufacturing

“Anyone who can solve the problems of water will be worthy of two Nobel prizes - one for peace and one for science” - John F. Kennedy

Introduction:

India has 18 percent of the world’s population, but only 4 percent of its water resources and only 2.45 percent of surface water, making it among one of the most water-stressed in the world. A large number of Indians face high to extreme water stress, according to a recent report by the government’s policy think tank, the NITI Aayog. Per Capita availability of water is reduced from 5177 Cu.m to 1486 Cu.m over last 70 years as per ministry of water resources. It is likely to further reduce to 900 Cu.m. by 2050. The conditions are worsened and more challenging due to climate change, intense flood in one area where as drought in other areas as well as very erratic monsoon.

Government of India realised the water scarcity in India and have taken proactive action by many schemes to make water available to citizen of India as well as Industries in India. In November 2019, the?Ministry of Jal Shakti for the first time set up a committee of independent experts to draft the new National Water Policy (NWP). ?The NWP is based on the consensus that has emerged through these wide-ranging deliberations and focuses on:

·???A shift?away from a supply-centric approach?involving dam construction and groundwater extraction, to managing demand and distribution of water.

·???Diversifying?public procurement operations?to include nutri-cereals, pulses and oilseeds to? encourage farmers to change their cropping patterns and save water.?

• Reduce-Recycle-Reuse for integrated urban water supply?and wastewater? management,?treatment of sewage and eco-restoration of urban river stretches?through decentralised wastewater management.
• Non-potable?uses of water?such as flushing, fire protection, vehicle washing?must mandatorily? shift to treated wastewater.
• The NWP points to huge amounts of water stored in big dams, which are still not reaching? farmers and explains?how irrigated area can be?expanded at very low cost by deploying? pressurised closed conveyance pipelines, combined with Supervisory Control and Data? Acquisition (SCADA) systems and pressurised micro-irrigation.
• Supply of water through?“nature-based solutions” such as the rejuvenation of catchment areas? through compensation?for eco-system services.
• Blue-green infrastructure in the form of rain gardens and bio-swales, restoration of rivers with? wet meadows, constructed wetlands for bio-remediation, urban parks, permeable pavements,? green roofs etc are proposed for urban areas.

Industries can participate, not only achieve water conservation in their own premises but improve water availability in near by areas to support new water policy.

Jal Jeevan Mission established in 2019, is envisioned to provide safe and adequate drinking water through individual household tap connections in rural area by 2024 by recharge and reuse through grey water management, water conservation, rain water harvesting as well as Amrit Lake. Jal Jivan Mission looks to create a jan andolan for water, thereby making it everyone’s priority, as it also increases water requirement. The transformation is shown in below mentioned figure which will also increase water requirement and increases stress on water availability.

?In this article, I shall talk about ideas for water conservation which I practiced in Industry over the years. You may check possibilities to implement at your plants.

WMS 1 : 5R principle: Most of the water conservation ideas in industries and commercial establishment follow 5R principles, i.e. Refuse, reduce, reuse,? recover, recycle. Always ask for 5R in every design, operation and maintenance related to water. You will see the glimpses of 5R in subsequent ideas.

WMS 2 :? First step in water conservation is to identify source and sink of water. Carry out water balance and identify gaps to understand actual consumption by each unit. Carry out audit to establish baseline water usage. Also establish quality of water required for various purpose and quality of waste water produced from different units. If required, provide water flow meters at all users to monitor and control water usage. Once unit knows the current state of water usage, further action can be possible. My experience says that most of people are ignorant of water balance of their site/plant.

WMS 3 : The largest water consumer in chemical industries is normally cooling tower. Cooling water Cycle of concentration (CoC) and it's blow down requirement is decided based on either allowable Chloride level or Calcium hardness level. By careful design and monitoring of water treatment program, operating chloride and calcium hardness can be increased to increase CoC and lead to water conservation significantly.

WMS 4 : Major water usage in cooling tower is evaporation loss to cool down water. For high load of cooling in condensers or cooling of high temp streams; process- process exchanger for energy recovery or use of air finned cooler can be economical option leading to reduction of?significant water evaporation in cooling tower.

WMS 5 : Cooling tower blow down is high TDS, high Silica stream but normally free of TOC/COD. It is reused for fire water being treated water, washing, flushing and cleaning of floor and equipment as well as for direct contact cooling by some of the operators.

WMS 6 : Boiler blowdown can be reduced and boiler drum CoC can be increased by careful design and monitoring of water? treatment of boiler drum. Change from fixed blowdown rate to on demand blowdown practices. Provide online conductivity meter to minimise blowdown.

WMS? 7 : Service water utility points are given in all chemical plants. Major loss of water can be running hose from such utility points even if it is not required. To minimise water wastage, install automatic shut-off nozzles to hoses, switch to high pressure- low volume nozzles.

WMS 8 : Many times running water hose are required for hot work in high hazards industries as per procedure. Review procedure and provide water hose with quick shut off valve / ball valve which can be opened in case of requirement.

WMS 9 : Normally water pumps gland is leaking lead to wastage of water. Check possibility to replace gland by single mechanical seal and stop water leakage.

WMS 10 : Condensate recovery in plants are observed 50-70% due to losses in traps, leaks, pressure loss in system. Strive to improve condensate recovery more than 90% by careful audit of malfunctioned trap, arresting leakages by online sealing as well as stopping very low pressure steam venting, reduce vent steam from low pressure vessels and deaerators, which is very much feasible.

WMS 11: Many of the industries require regular floor cleaning due to dust accumulation. Normally fresh water is used. It is possible to use treated effluent for floor cleaning.

WMS 12 : Water is mainly used in industries for once through cleaning of equipment, floor etc. Now with technology advancement, for many applications, water free cleaning process or circulating water cleaning processes are developed. Identify such alternate equipment and floor cleaning process which are free of freshwater. E.g. vacuuming to remove solids and dust, UV bath for filter elements,? back flushing, oxidation etc.

WMS 13: Use of non-potable water/ treated effluent water for industrial services, e.g. Fire water, effluent water pH adjustment or dilution, floor washing, equipment cleaning, atmospheric scrubbers etc. Many industries uses drinking water for above mentioned services, it can be replaced by non-potable water / treated effluent water/ cooling tower blowdown.

WMS 14: Condensate is recovered and? recycled after polishing to remove contaminants. However, when treatment of boiler drum and steam is working well, iron pick up from steam and condensate system is negligible. In such cases, it is possible to recycle/reuse major part of the condensate directly to deaerator for energy and water saving. The stream for direct recycle to be selected based on risk assessment of possibility of contamination due to process upset or process fluid leakage.

WMS 15 : Cleaning of filter, equipment, etc is periodically done many times. Review and reduce cleaning?schedule from periodic and regular?to need based cleaning. Use water bath instead of cleaning under continuous sprinklers. Provide necessary indication e.g. DP meter; to assess cleaning requirement.

WMS 16 : Water pinch analysis for chemical, petrochemical and refinery complex is not new concept. As the plants are built in phases, this concept is normally overlooked while design. It is essential to carry out water pinch analysis for reuse, recover and recycle water. I propose following stages to prepare road map for zero liquid discharge.

·??Carry out pinch analysis and identify reuse of water based on quality requirement and re-route it.

·??Segregate low TDS stream which can be recycled with minimum reject and with minimum treatment.

·??Segregate high TDS water where water is free of silica and Calcium / magnesium salts. I.e. only sodium salts. This can be recovered and recycled at slightly higher level of treatment.

·??Balance water can be recycled with extensive treatment.

·??If target is for zero liquid discharge, identify waste steam/ heat available with in process which is lost to atmosphere and plan for water recovery in multi stage evaporators.

WMS 17 : Water conservation while land-scaping. Many commercial and industrial facilities have landscapes that require irrigation. In my recent assessment of one of facility, water consumption of gardening was very high.? Taking action to make this efficient can save a lot of water.

·??Use native plants or other plants that require little water to thrive in your region.

·??Do not turf grass in all open areas. Plant turf grass only in areas where people will use it actively for recreation.

·??Use efficient water sprinklers for watering of turf grass and maintain it in good condition.

·??Use drip irrigation and/ or micro irrigation for watering of plants.

·??Organize your landscape into hydrozones.?Hydrozones are areas of landscape with plants and vegetation that have similar water requirements.? This prevents overwatering of some plants and avoids under-watering of others.

·??Keep soil healthy and add mulch to prevent water loss through evaporation.

·??If watering with a hose, make sure it has a shut-off nozzle.

·??Water landscapes in the morning to prevent water loss due to evaporation.? Avoid watering when it is windy.

·??Use a rain barrel and rain pond to collect water for use in the landscape.

?WMS 18 : Domestic water consumption reduction

There are many possibilities to reduce or recycle Domestic water consumption by

·?Stopping leakage of water from sink, toilets, safety showers etc. immediately after it is identified.

·? Installation of water efficient faucets, shower heads and toilet flush

·?Provide auto stop valves or sensor based valve operation for wash basin and urinals

·?Use of water less urinals to minimise water usage.

·?Use of treated effluent water for Toilet flush

·?Provide sewage treatment plant and reuse water for process requirement as many old buildings have still soak pit

·?Provide water level controllers for overhead tanks

·?Target for water consumption of less than 30 lits per person per day.

?WMS 19 : Water Harvesting

Rain water harvesting is now a day, very well accepted practice in water scarce area. Rain water can be harvested in

·?Open pond for reuse it for process

·?Recharge to ground to increase ground water level and extraction by bore well after monsoon.

·?Normal practices are to harvest rain water from roof and clean area and recharge to ground in the monsoon season.

·?For large water pond available in nearby area, rain water can be diverted to open pond by gravity or by pump.

·?Provide piezo meter, if rain water is charged to ground to see its effectiveness.

WMS 20: Water Audit

Water audits are very effective way to identify water conservation opportunities as it is focused approach. Carry out first party and second party water audit once a year and third party water audit at least once in three years. Take help of experts for innovations and initiatives.

?WMS 21 : Water Manager

Nominate water manager in your facility to ensure all water conservation measures, training as well as audits are regularly taking place. Also associate and involve all employees and contract work man for water conservation drive. Establish system for incentive linked suggestions scheme for water conservation.

?WMS 22 : Water Dash board

Peter Drucker’s famous quote, “What gets measured, gets done.” It is essential to make dash board and map water balance, actual and design water consumption for each consumers as well as actual and design water quality required.

?WMS : 23 Fire water line leak

In high hazards industries, fire water lines are provided under ground. Due to internal or external corrosion, line leaks lead to very high loss of fire water and continuous operation of its Jocky pump. It is preferable to provide fire water line above ground to identify and arrest leakage. If already provided underground, ensure, it is flushed periodically and water is recovered to avoid stagnancy and subsequent corrosion.

?I am sure that Professional Chemical Engineers will appreciate their role to actively take up the ideas to execution for sustainable manufacturing and becoming water neutral or water positive.

In last three articles, we discussed about energy and water conservation ideas. I shall appreciate, if you can pick up some of the ideas and send me feedback.

?# “Water is critical for sustainable development, including environmental integrity and the alleviation of poverty and hunger, and is indispensable for human health and well-being.” – United Nations

?The author is Founder and Chief Consultant, Innov8 ProTech Solutions, The Sustainability and Management Consultant. Formerly, he was Sr. Vice President (Head- Technical) at Reliance Industries Ltd. He is also a member of the IIChE Chemical Process Safety, Energy and Environment Committee from 2018 to 2024.

Since last Six years, he is consulting for Energy and Water Management, Green company advisor and branding for Sustainable Manufacturing as well as Process Safety and Risk Management.

The author holds following degrees and certifications.

(B.E. (Chem.), C. EA, F.CMA, IGBC AP, ISO50001:2018 Auditor, ISO45001:2018 internal Auditor, Early Professional in Climate change and Environment Sustainability), Finalist of Indian Climate Change Champion League 2020.

Email: [email protected]; Mob: +919374715109