Process Heating Dan Zhou CREST Loughborough University Research - - PowerPoint PPT Presentation

Thermal Energy Storage for Medium Temperature Industrial Process Heating

Dan Zhou

CREST Loughborough University

Research Proposal

• Heat storage media:

Material preparation, thermal property measurement, thermal stability and reliability test, chemical stability test;

• Heat storage system design and build up

Heat storage tank, heat transfer method, high temperature heat exchanger, high temperature oil pump, flow meter and other equipment;

• Heat charging and discharging analysis:

Experimental and numerical;

• Valuation of the heat storage system and improvement:

Cost, running efficiency and heat transfer enhancement.

Binary system of molten salts

• A binary system of LiNO3 and

NaCl (87mol%/13mol%) is selected as the heat storage medium because

• f its high phase transition enthalpy.
• Thermal properties by DSC:

The samples were heated from 50°C to 260°C then cooled down to 50°C at a heating/cooling rate of 10 ºC/min and 15 ºC/min.

• Thermal stability and reliability by DSC and TGA:

11 heating/cooling cycles by DSC 5 heating/cooling cycles by TGA at a heating/cooling rate of 10 ºC/min

Binary system of molten salts

Binary system of molten salts

• Weight loss vs temperature

tested by TGA: 5 cycles.

• Corrosion test

Copper Alloy Steels Austenitic. Grade 304 Austenitic. Grade 316

Heat Storage System

Charging temperature at 280 °C Discharging temperature at 160°C

Heat Storage System

0.4 m 0.2 m 0.14 m O.D 0.015 m 1.5 do

𝑬: Diameter of the tank; 0.2m 𝒆𝒑: Outside diameter of the heat transfer tube; 0.015m H: Tank height; 0.5m F: Coil height; 80% of the tank height; 0.4m C: Top height; C=(H-F)+0.1=0.5- 0.4+0.1=0.2m A: Coil gap; A=1.5𝒆𝒑=0.022m r: Radius of the coil; 0.07m Heating power: Q=1.5kW Charging/ discharging time (approximately and ideally): 1.5 hour

Heat Storage System

• High temperature oil pump (Turbine

pump) STM Series, Low flow and high head; stainless steel 316L; capacity can up to 10 m3/h; head is up to 80 m Operating temperature: 300°C

• IC-LPM industrial paddle wheel

series flow meter: Flow range: 2-20 L/min Operating temperature: 350 °C Material: 304 stainless steel Out/Display: IC-MV-AN analogue 4/20mA out put module Repeatability: 0.1% of reading Linearity: 0.5% FSD

• Multifunction Data Acquisition

National Instruments USB-6225

• High temperature heat exchanger

Tube-in-tube heat exchanger (high temperature, high pressure and low flow) Material: stainless steel 316L Heat transfer rates to 29 kW Liquid flows to 38 L/min