Fluxara — Energy Recovery, CO₂ Monetisation & ETP Innovations

DISCOM constraint — 400 kWp is the hard ceiling: TSERC net metering rules cap solar installation at 80% of sanctioned load. Sanctioned load = 500 kW → max solar panel installation = 400 kWp. This is the regulatory limit, not an economic choice. DPR already has 250 kWp; incremental = +150 kWp to reach the 400 kWp cap.

Solar PV — 400 kWp Maximum (150 kWp incremental from DPR 250 kWp)

Sangareddy: 5.5–6.0 kWh/m²/day · DISCOM cap: 80% × 500 kW sanction = 400 kWp max installation

₹1.20 Cr

Total 400 kWp capex

₹0.13 Cr

Incremental saving/yr (+150 kWp)

2.4 yr

Payback (post-subsidy)

₹0.35 Cr

Total saving/yr at 400 kWp

400 kWp Installation Cap — Derating to Effective Output

Derating Factor	Loss %	Effective kW
Panel rated output (DISCOM cap)	—	400 kWp
Temperature derating (40-45°C ambient)	−8%	368 kW
Soiling + shading	−3%	357 kW
Inverter efficiency	−3%	346 kW
Cable + transformer losses	−2%	~339 kW

400 kWp installed → ~339 kW effective peak output. Covers 75% of operating load (454 kW) during peak sunshine (~6 hrs/day), displacing ~22% of 24-hour grid draw.

System Component	Cost (400 kWp)
Panels (Tata Solar / Waaree, 400 kWp)	₹56L
String inverters (SolarEdge / SMA)	₹20L
MS structure + cable trays	₹15L
AC/DC cables + protection	₹10L
Net meter + TSERC compliance	₹8L
Civil (ground mount foundation)	₹8L
EPC margin + commissioning	₹3L
TOTAL (400 kWp)	₹1.20 Cr

Incremental Economics (Beyond Existing DPR 250 kWp, up to DISCOM cap)

Existing (DPR)

250 kWp already in DPR

315,000 kWh/yr

₹0.22 Cr/yr saving

~₹75L capex (in DPR utilities bundle)

Incremental (to DISCOM cap)

+150 kWp to reach 400 kWp total

+189,000 kWh/yr additional

+₹0.13 Cr/yr saving

₹0.45 Cr capex (₹1.20 − ₹0.75)

Payback: 3.4 yr gross

Post TSREDCO Subsidy (30%)

TSREDCO + PM-KUSUM Component C

30% on ₹0.45 Cr = ₹13.5L subsidy

Net capex: ₹0.32 Cr

Payback: 2.4 yr ✓

Hard ceiling at 400 kWp: DISCOM will not approve solar net metering beyond 80% of your 500 kW sanctioned load — this is the regulatory limit, not an economic one. To go beyond 400 kWp you would need a load enhancement application to DISCOM (possible at Phase 1B/Phase 2 when installed load increases to 600–700 kW). At that point, the new 80% cap would be 480–560 kWp. Revisit this at Month 18 alongside Phase 1B sanction enhancement.

CO₂ Bottling Plant — 1.5 MT/day Industrial Grade

10% of 15.69 MT/day surplus · MEA absorption · Stripper heat from THU surplus (zero cost)

₹1.50 Cr

Capex

₹0.59 Cr

Revenue/yr

₹0.46 Cr

EBITDA/yr

3.2 yr

Payback

CO₂ Mass Balance — Where the Carbon Goes

Rice husk combustion
25.05 MT/day CO₂

Gross CO₂ produced

→

PCC precipitation
9.36 MT/day

Used in process (5% excess)

→

Surplus (currently vented)
15.69 MT/day

5,178 MT/yr to atmosphere

→

Capture 10%
1.5 MT/day

495 MT/yr bottled

→

Remaining surplus
14.19 MT/day

BCR credits potential (Y3+)

Process Flow

1. Flue gas cyclone
Remove fly ash + particulates

Already required for
TSPCB compliance

2. NaOH scrubber
Remove SOx to <10 ppm

Already planned for
flue gas cleaning (₹8-15L)

3. MEA absorption column
85-90% CO₂ capture into amine solution

₹50L (local fab)

4. MEA stripper (heated)
Release CO₂ · heat from THU surplus

ZERO fuel cost
4.5 GJ/day from surplus

5. 3-stage compressor
Compress to 60 bar · Kirloskar/ELGi

₹30L · 15 kW avg power

6. Drying + liquefaction
Molecular sieves → −20°C liquid CO₂

₹10L dryer · integrated
with compressor last stage

7. Storage + filling
10 MT insulated tank · cylinder manifold

₹40L · 1 operator

Capex Breakdown

Item	₹ Lakhs	Note
MEA absorption + stripping (local fab SS316)	50	BHEL/Praj local fabricator
CO₂ compressor 3-stage (Kirloskar)	30	Made in India · spares local
Molecular sieve dryer	10	Standard skid
Liquid CO₂ storage (10 MT insulated)	25	Vacuum insulated vessel
Cylinder filling station + manifold	15	50 cylinders capacity
Civil + piping + E&I + SCADA	20	Adjacent to furnace
TOTAL CAPEX	150	= ₹1.50 Cr

Annual Economics

Item	₹ Cr/yr
Revenue: 495 MT/yr × ₹12/kg industrial CO₂	+₹0.59
Welding gas: ₹12–15/kg · Fire suppression: ₹15–18/kg
MEA solvent makeup + chemicals	−₹0.04
Electricity (compressor ~15 kW avg)	−₹0.02
1 additional operator (₹3.5L CTC)	−₹0.04
Maintenance	−₹0.03
Stripper heat (4.5 GJ/day from THU surplus)	₹0.00 cost
EBITDA	₹0.46 Cr/yr

EBITDA MARGIN

78%

PAYBACK

3.2 yr

Key advantage: The MEA stripper requires heat at ~120°C — this comes from the THU thermal oil circuit (83 GJ/day surplus). Needs only 4.5 GJ/day (5.4% of surplus). This is the only industrial CO₂ capture setup in India where stripping heat is free. Most competitors pay ₹800–1,200/GJ for this heat; Fluxara pays zero.

Y2 upgrade path: Once industrial CO₂ offtake is established, upgrade purification to food-grade (CO₂ purity 99.99%, add activated carbon + molecular sieve column, ₹15L additional). Food-grade CO₂ prices: ₹28–38/kg vs ₹12/kg industrial — EBITDA rises to ₹1.0+ Cr/yr with same capex base.

Prerequisite: Lock an offtake buyer before ordering the MEA column. Target: Air Liquide India / Inox Air Products / regional welding gas distributors in Hyderabad (Patancheru / Balanagar belt). They often prefer to operate the bottling themselves — negotiate a tolling model where they install the compressor/storage at their cost and pay you ₹7–9/kg for CO₂ at the plant gate. Lower your capex to ₹65–70L (just absorption + cyclone); their ROI is fine at ₹3–5/kg margin.

Heat Integration & Recovery Matrix

THU thermal oil circuit · 83 GJ/day surplus in Y1 · 74 GJ/day post Phase 1B

₹50L

Total capex (excl. causticiser)

₹1.19 Cr

Total saving/yr

0.4 yr

Blended payback

0.47

₹/1% NaOH recovery

Thermal Surplus Map — Where the Energy Actually Goes

HEAT AVAILABLE

Rice husk NCV (20 MT/day)

243.0 GJ/day gross

After boiler losses (82% eff.)

199.3 GJ/day useful

CaO slaking exotherm

15.2 GJ/day @ 80-100°C

Spray dryer exhaust

6.5 GJ/day @ 65-95°C

HEAT CONSUMED

Evaporation (with MVR)

58.5 GJ/day

NaOH leaching @ 90°C

42.7 GJ/day

Spray drying

15.1 GJ/day

CO₂ stripper (if built)

4.5 GJ/day

Phase 1B (Month 18)

9.0 GJ/day

SURPLUS (RECOVERABLE)

Y1 thermal surplus

83.0 GJ/day

After CO₂ stripper

78.5 GJ/day

After Phase 1B (Month 18)

69.5 GJ/day

Phase 2 anchor

~69 GJ/day remaining

Heat Recovery Projects — Ranked by ROI

★ Draft-Tube Causticiser (CHAMPION ROI)

Capex₹30–35L

NaOH recovery82% → 86–88%

NaOH saving/yr₹0.94–1.88 Cr

PCC quality upliftd50 0.5–0.8 µm → sealant grade direct

Payback<0.4 years

How it works: Dorr-Oliver draft-tube design creates controlled turbulence in causticisation vessel → better Ca(OH)₂–Na₂CO₃ contact → 86–88% conversion vs 82% in standard tank. Finer CaCO₃ crystals (0.5–0.8 µm d50) are sealant grade directly without post-processing. Install at commissioning — not a retrofit.

CaO Slaking Exotherm Recovery

Capex₹10–12L

Heat available15.2 GJ/day @ 80-100°C

Recovery (30%)4.6 GJ/day

THU load reduction~4%

Saving/yr₹0.15 Cr

Payback0.8 yr

How it works: Slaker discharge (Ca(OH)₂ slurry at 80–100°C) passes through a plate heat exchanger before entering the causticiser. Pre-heats NaOH leach feed water from ambient to 60°C, cutting THU load on leach circuit. Equipment: one SS316 gasketed plate HX from Alfa Laval India. Zero moving parts. Sangareddy summers make this particularly valuable (ambient 40–45°C reduces temperature lift needed).

Spray Dryer Exhaust WHR Recuperator

Capex₹8L

Exhaust temp65–95°C

Heat recovered6.5 GJ/day

UsePre-heat incoming drying air

Saving/yr₹0.10 Cr

Payback0.8 yr

How it works: Air-to-air rotary heat exchanger (recuperator) on spray dryer exhaust duct. Pre-heats incoming ambient air from ~40°C to ~70°C before entering the spray dryer inlet heater. Reduces THU heat load on spray dryers by 6–8%. SS316 recuperator from Heatex India or local fab. Simple retrofit, no process change.

MVR on Evaporator (DPR Mandatory)

Capex₹150L (in DPR)

Without MVR167.1 GJ/day evap load

With MVR58.5 GJ/day (−65%)

Heat saved108.6 GJ/day

Without MVR25.6 GJ/day deficit → plant stops

StatusAlready in DPR · Non-negotiable

This is not optional. Without MVR, thermal deficit = 25.6 GJ/day and plant cannot operate at design throughput. Already included in ₹150L triple-effect evaporator line item. Also enables the 83 GJ/day thermal surplus that makes Phase 2 and CO₂ plant viable.

ZLD MVR (Included in ETP+ZLD)

CapexIncluded in ₹120L ZLD

ZLD water recovery80%

ZLD electricity~8 kWh/m³ treated

Fresh water makeup84 KLD (Ph1A)

StatusIn DPR from Day 1

ZLD MVR compresses the vapour from the first evaporation stage to heat the second stage — same principle as process MVR. Reduces ZLD electricity from ~25 kWh/m³ (multi-effect without MVR) to ~8 kWh/m³. Already designed into the ETP+ZLD ₹120L capex.

ORC Electricity Generation (Phase 2 / Y3+)

Available surplus (post Ph1B)~69 GJ/day

ORC efficiency10–12% (at 150–180°C)

Power potential~800–1,000 kW

Revenue/yr₹1.8–2.2 Cr/yr (grid export)

ORC capex₹8–12 Cr

Payback4–6 yr (not Y1/Y2)

Not recommended for Y1–Y2. ORC at this scale costs ₹8–12 Cr (Turboden/Exergy Europe). Revenue only ₹1.8–2.2 Cr/yr on a ₹10 Cr investment = 4–6 yr payback. Defer to Y3 or Phase 2 once capital is freed. Better use of the thermal surplus: add a second production line (Phase 2) which turns heat into ₹20+ Cr revenue, not ₹2 Cr in electricity.

ETP / ZLD Innovations — Sangareddy Conditions

Semi-arid climate · 2,000 mm/yr evaporation · 5 acre land (3 TSIIC + 2 buffer) · 84 KLD fresh water input

₹27L

Total capex

₹0.13 Cr

Annual benefit

2.1 yr

Blended payback

80%

ZLD water recovery

ETP Water Balance — How 84 KLD Moves Through the Plant

Fresh water intake
84 KLD

Groundwater + TSIIC supply

→

Process use
84 KLD

Leaching · causticisation · spray drying

→

ETP treatment
~100 KLD

pH adj · coagulation · clarification

→

ZLD evaporation
80% recovery

67 KLD recycled back to process

→

ZLD concentrate
~17 KLD

To evaporator → salt cake

Solar Evaporation Pond

What: 0.25 acre HDPE-lined evaporation pond receives ZLD concentrate (17 KLD) before the MVR evaporator. Sangareddy has 2,000 mm/yr evaporation rate — the pond evaporates 3–5 KLD naturally, reducing MVR evaporator duty by 20–30%.

Capex: ₹5L (HDPE liner 400 gsm + earthwork + inlet pipe)
Saving: Reduces ZLD electricity 15–20% = ₹3–4L/yr on power bills
Monsoon management: Install a polyethylene roof cover or seasonal bypass during Jun–Sep (Sangareddy: 700–900 mm monsoon). This pond is the cheapest KLD of treatment in the entire plant.

Also captures: Sodium compounds in concentrate begin crystallising → reduces scaling in the MVR evaporator (extends cleaning intervals from 6-monthly to annual).

ETP Polished Water — Fish Pond

What: ZLD polished water (pH 7.5–8.5, BOD <5 mg/L, TSS <10 mg/L) is suitable for freshwater aquaculture. 0.5 acre pond fed from ETP tertiary treated water. Stock catla, rohu, and tilapia (all Telangana-native, fast-growing, high local demand).

Capex: ₹7L (pond excavation + HDPE liner + fingerling stock + net)
Yield: 2–2.5 MT fish/yr at 2,000 fingerlings/0.5 acre stocking density
Revenue: ₹130/kg at local Sangareddy fish market = ₹2.6–3.2L/yr

Dual benefit: (1) Revenue, (2) TSPCB inspector goodwill — demonstrating beneficial use of treated water is excellent for CTO renewal. Sangareddy fishing community may also be interested in a lease arrangement (they manage it, you get ₹1L/yr ground rent).

ZLD Salt Cake Partial Recovery

What: ZLD evaporator produces a mixed salt cake. The Fluxara process generates primarily sodium carbonate (Na₂CO₃) and calcium carbonate (CaCO₃) in the concentrate. A simple crystallisation step on a side-stream can separate a partial Na₂CO₃ fraction.

Capex: ₹15L (crystallisation vessel + centrifuge, small-scale)
Yield: 30–40 MT/yr Na₂CO₃ partial-grade (not reagent-pure, but suitable for wastewater treatment or tile manufacturing)
Revenue: ₹10,000/MT = ₹3.5–4L/yr
Benefit: Also reduces hazardous waste disposal cost (ZLD salt cake classified as industrial waste needing approved disposal = ₹3,000–8,000/MT disposal fee). Every tonne recovered is ₹10K earned + ₹5K disposal avoided.

Alternative: License the salt cake to a cement manufacturer (CaCO₃-rich ash can substitute 5–10% of limestone in clinker) at ₹500–1,000/MT gate. No processing needed. ₹1.5–3L/yr, zero capex.

ETP Design for Sangareddy Conditions — Key Specifications

Climate Adaptations

→Design ETP for 45°C summer peak — polymer doses shift with temperature
→Monsoon (Jun–Sep): ETP flow doubles from storm run-off — size clarifier for 2× peak
→RCC sump (not HDPE tank) for main equalization — cheaper and permanent at this scale
→Use local lime (CaO from Nalgonda) for pH neutralisation — ₹6,000/MT vs proprietary pH chemicals ₹25,000+/MT

TSPCB Compliance Focus

→ZLD mandatory from Day 1 (TSPCB condition for process plant in this category)
→Online pH + TSS sensor to TSPCB portal (auto-log, required for CTO)
→Fish pond acts as informal bio-indicator — TSPCB inspectors respond positively
→Monthly self-monitoring lab report to TSPCB as required by consent conditions

Water Cost Optimisation

→Bore well + TSIIC supply dual feed — bore is ₹3–5/KL vs TSIIC ₹40–60/KL
→84 KLD makeup × ₹5/KL bore rate = ₹1.5L/yr vs ₹18.5L/yr TSIIC water — saves ₹17L/yr
→ZLD 80% recovery means only 84 KLD fresh needed for 420 KLD total process water
→Groundwater NOC from CGWB — apply through TS-iPASS single window

Total Add-On Capex

₹2.64 Cr

All 5 projects (solar corrected)

Total Add-On EBITDA

₹1.91 Cr/yr

When all fully operational

Blended Payback

1.4 yr

Portfolio-weighted average

Funding Source

Y1–Y2 accruals

Zero additional bank debt

Portfolio Summary — All Capital Projects Ranked by Payback

Project	Capex	EBITDA/yr	Payback	Payback Visual	Fund From	Priority
▶ COMMISSION DAY 1 — Install at build, no additional fundraising
Draft-tube causticiser NaOH 82%→87% + sealant PCC direct	₹0.35 Cr	₹0.94 Cr	0.4 yr	0.4yr	Add to commissioning budget	P1 · NOW
CaO slaking HX + spray dryer WHR Plate HX + recuperator	₹0.20 Cr	₹0.25 Cr	0.8 yr	0.8yr	Commissioning budget	P1 · NOW
ETP fish pond + solar evap pond + salt recovery 3 small ETP innovations	₹0.27 Cr	₹0.13 Cr	2.1 yr	2.1yr	Y1 minor capex	P2 · Y1
▶ FROM Y1 ACCRUALS — After Phase 1B (₹1.50 Cr) is funded
Solar 400 kWp total (DISCOM cap) +150 kWp incremental · TSREDCO 30% subsidy · 80% of 500 kW sanction	₹0.32 Cr net	₹0.13 Cr	2.4 yr	2.4yr	Y1 end / Y2 early	P2 · Y1-Y2
CO₂ bottling plant (1.5 MT/day) MEA absorption · THU surplus heat · industrial grade	₹1.50 Cr	₹0.46 Cr	3.2 yr	3.2yr	Y2 accruals (after Ph1B)	P3 · Y2
▶ REFERENCE — Already in DPR (not additional capex)
MVR on process evaporator Mandatory · in DPR ₹150L	₹1.50 Cr (DPR)	₹3.30 Cr	0.5 yr	DPR	Bank term loan	MANDATORY
Solar 250 kWp existing Already in DPR utilities bundle	~₹0.75 Cr (DPR)	₹0.22 Cr	3.4 yr	DPR	Bank term loan	IN DPR
TOTAL Add-On Projects (P1–P3, solar corrected)	₹2.64 Cr	₹1.91 Cr/yr	1.4 yr avg		Y1–Y2 accruals only

Funding Waterfall — Y1 Accruals (Full Optimisation Scenario)

Y1 Cash Available (Full Optimisation)

EBITDA+₹5.04 Cr

Less: interest (moratorium)−₹2.11 Cr

Y1 net cash+₹2.93 Cr

T-IDEA SGST rebate (Y1–Y5)+₹1.26 Cr

Total Y1 deployable cash+₹4.19 Cr

Y1 Cash Allocation Priority

#1 Phase 1B (non-negotiable)₹1.50 Cr

#2 Heat integration (Day 1 capex)₹0.20 Cr

#3 ETP innovations₹0.27 Cr

#4 Solar incremental (+ subsidy)₹0.52 Cr

Total deployed from Y1₹2.49 Cr

Remaining for CO₂ plant (Y2)₹1.70 Cr

The sequencing logic: Draft-tube causticiser (₹35L, 0.4 yr payback) is the highest-priority addition — install at commissioning, not as a retrofit. Heat integration pays back in <1 year. CO₂ plant (₹1.50 Cr) waits for Y2 once Phase 1B revenue is established, and ideally use the tolling model (₹65L capex vs ₹1.50 Cr) to get CO₂ revenue stream running earlier with less risk.